Factors contributing significantly to antibiotic use included ward bed capacity, physician to nurse ratio, average hospital stay, and pneumonia to preterm infant ratio. Our data suggested that the use of antibiotics among inpatient newborns in advanced hospitals in mainland China was prevalent and should be subject to rigorous monitoring, and highlighted the need to explore how newborn ward bed capacity potentially impacts antibiotic use.Previous surveys of neonatal medicine in China have not collected comprehensive information on antibiotic use in newborns. The goal of the present study was to assess the trends in antibiotic use in inpatient newborns from advanced hospitals in mainland China and to evaluate the contributing factors. We extracted retrospective data on newborn clinical units from a database containing key clinical subspecialty area indicators from provincial or ministerial (Class A level III) hospitals over three consecutive years (2008–2010) and in 25 of 31 provincial districts of mainland China. Fifty-five newborn units were included in the study. The results showed that two thirds (65.7% ± 23.1%) of inpatient newborns were prescribed antibiotic products. Antibiotic use rates were significantly different by newborn ward bed capacity ( Overuse of antibiotics is now a major health concern worldwide, primarily due to the spread of antibiotic resistance and its public health consequences but also because of its impact on individual health outcomes. ExposurMore reports of antibiotic use from China are related to adults and children than newborns. Results from a meta-analysis showed that country-wide, 50.3% of adult outpatients were prescribed antibiotics, with higher rates of prescription in the less developed areas of western China. A natioResearch suggests that there are a number of underlying factors that influence antibiotic prescription including, financial incentives provided by pharmaceutical industry, 12, a pIn 2011, three ministries including National Health and Family Planning Commission of the People’s Republic of China (NHFPC) initiated a national initiative to develop key clinical subspecialties for the country. We usedWe used retrospective cross-sectional data covering a period of three consecutive years 2008–2010). Data were extracted from proposals submitted to the NHFPC. All participating hospitals were required to provide detailed information, including indicators of institutional infrastructure, workforce, health-care service, education, and research08–2010. . The infOf the 31 provincial districts in mainland China, three provinces  that were relatively underdeveloped with respect to socioeconomic and health, did not submit applications. In all,We selected indicators of health infrastructure, workforce, health service, and social and economic factors. Due to the unequal geographical distribution of the Chinese population and participating hospitals, we used the four broad geographical classifications according to the National Bureau of Statistics of China: Northern China (North China and Northeast China), East China, South Central China, and Western China (Southwest China and Northwest China). The newborn units were situated in three different hospital types: CH, GH, and MCH.Data on health infrastructure and workforce reflect the situation at the end of 2010. Subspecialty beds are those registered at health authorities. The health workforce consists of full-time physicians and nurses with practicing certificates. Workforce indicators are number of physicians, number of nurses, nurse to bed ratio, physician to nurse ratio, proportion of physician with graduate degree, and proportion of nurses with at minimum a college certificate.Given the fact that different newborn units may have different disease compositions, we chose pneumonia to preterm infant ratio, namely the proportion of pneumonia to preterm infants according to hospital discharge diagnosis codes, as a rough indicator of disease compositions. This approach was based on the facts that, within the investigation period, pneumonia and preterm infants were the two most common diseases in newborn units in China; and infants with pneumonia were prescribed antibiotic for treatment, while preterm infants with the gestational age between 34 and 36 weeks, who accounted for a majority of premature birth, may not be routinely prescribed antibiotic for treatment. Thus, a lower pneumonia to preterm infant ratio may suggest that a unit treated more immature babies, and a higher ratio may suggest that a unit was more likely to use antibiotics.The primary outcome was the rate of inpatient antibiotic use, defined as the proportion of hospital discharges in which a patient received at least one dose of an antibiotic during the stay year, 24. AnnWe used means and standard deviations (SD) to explore the data. Arithmetic means of rates were used to compare antibiotic prescription rates across cities. We first conducted one-way analyses of variance (ANOVA) to compare different rates of antibiotic use across regions, hospital types, newborn ward capacity , as well as admission to physician or nurse ratio, proportion of physician with graduate degree, and ratio of nurse with college or above degree (each indicator divided in quartiles). We reduced the variables of workforce and workload to two components  by using Factor Analysis with a principal components extraction. Due to the versatility of the generalized estimating equation (GEE) approach in analyzing longitudinal measures with repeated and categorical data, we condInfrastructure and workforce of the participating hospitals were somewhat different . OverallOver the three years, the mean rate of antibiotic use was 65.7%±23.1% (median: 68.1%). The rate of antibiotic use varied from 13.7% to 100% across the 55 hospitals. There was a decline of 5.4% over the three-year span, but the difference was not significant: 2008 (67.8%±23.0%), 2009 (66.8%±23.0%), and 2010 (62.4%±24.2%).p = 0.023). Newborn units with more than 100 beds had the highest rate of antibiotic use (77.1%), compared to units with 50 or fewer beds (60.6%), and those with 51–100 beds (61.3%). We found no significant differences in antibiotic use across type of hospital, geographic area, physician or nurse academic degree, or annual admission to physician or nurse ratio  of inpatient newborns were prescribed antibiotic products during the period 2008 to 2010. A number of factors are shown to predict the rate of antibiotic prescription namely infrastructure (newborn ward capacity), workforce (physician to nurse ratio), and medical service uptake .The wide variation and overuse of antibiotic agents in newborns is a world-wide concern. One study of 127 NICUs in the USA found that overall antibiotic use varied 40-fold, from 2.4% to 97.1% of patient-days (median: 24.5%). A high The study finding on contributing factors should be considered with care. It is understandable that the nature of diseases impacts antibiotic usage. For example, infants with pneumonia can be routinely treated with antibiotics in China, while premature births may not be an indicator of antibiotic use unless infection is suspected. The finding that antibiotic use was positively associated with high physician to nurse ratio, may suggest that shortage of nurses in newborn units increases the possibility of hospital infection, and thus antibiotic prescription for sick newborns. Meanwhile, studies prove that nurse to patient ratio influences many nurse-sensitive patient outcomes, 32, andTo our knowledge, this is the first report that newborn ward capacity influences antibiotic usage in inpatient newborns. This finding of the association between unit bed capacity and antibiotic usage can be supported by a national survey in China showing that hospitals with fewer than 300 beds had a significantly higher rate of antibiotic usage than those with more than 300 beds; and a systematic review of antibiotic utilization showing that hospital levels influenced the rate of antibiotic prescriptions among outpatients in China, where level I hospitals (primary care centers) were associated with higher antibiotic use than hospitals in high-level hospitals. FurtherThere is much room left to reduce antibiotic overuse in newborn units. The report by The Centers for Disease Control and Prevention in the USA stated that one-third of antibiotic prescriptions in hospitals involved potential prescribing problems, such as unnecessary antimicrobial therapy, prescribing an antibiotic without proper testing or evaluation, or giving an antibiotic for too long , 37. TheOn a more encouraging note, our results show a decreasing trend in antibiotic usage over the three-year period, which constitutes a decrease of 17% compared to the results (83.4% in newborns) from 178 hospitals of China in 2001.This study has several limitations. First, our results draw on administrative data on level III neonatal hospitals in China, meaning that the results do not reflect the situations of level one and level two hospitals. Second, we did not detail antibiotic prescribing patterns in the units to explore correlations with the presence of any indication, due to the fact that the available data were not acquired from an antibiotic-oriented site investigation. The strengths of the study are twofold. First, to our knowledge, it is the first study to systematically explore a range of factors that may contribute to the prescription of antibiotics. Second, the study examines usage over a three-year period, and thereby providing a baseline for future longitudinal studies.This retrospective analysis provides a comprehensive description of antibiotic use in inpatient newborns across advanced provincial and ministerial hospitals in China over a three-year period. Factors that contribute to antibiotic prescription include newborn ward bed capacity, physician to nurse ratio, disease composition, and average hospital stay. The data highlight the need to explore how subspecialty scale of newborn medicine potentially impacts the rate of antibiotic use among inpatient newborns.S1 Table(DOCX)Click here for additional data file.


This study found that inappropriate antibiotics were prescribed in 17% of bacteremia patients presenting at the ED and that high pulse rate was an indicator for appropriate antibiotic prescription. Patients with inappropriate antibiotic administration had longer hospitalization and higher 28-day mortality than those who received appropriate antibiotic treatment.Sepsis is a condition that requires appropriate antibiotic treatment at the emergency department (ED). Most previous studies conducted on inappropriate antibiotic use at the ED were conducted in developed countries with a low percentage of sepsis. This study aimed to find additional clinical predictors for appropriate antibiotic use in bacteremia patients presenting at the ED from a developing country, in which there is a higher proportion of patients with sepsis. We included adult patients who presented at the ED with clinical suspicion of infection and bacteremia. Patients allocated to the appropriate antibiotic group were those in whom the prescribed antibiotic was sensitive to the pathogen. Predictors and outcomes of appropriate antibiotic use were analyzed. A total of 3133 patients who met the study criteria presented at the ED during the study period. Of those, 271 patients were diagnosed with bacteremia, 48 of whom (17.71%) received inappropriate antibiotic prescriptions. Only pulse rate was an independent factor for appropriate antibiotic treatment, with an adjusted odds ratio of 1.019 . In terms of clinical outcomes, the inappropriate antibiotic group had higher proportions of 28-day mortality (29.17% vs. 25.25%;  Sepsis is a life-threatening condition that is a major problem worldwide. In the United States, there were over 750,000 cases in 1995, 61% of whom were admitted through the emergency department (ED) . In ChinAppropriate and adequate antibiotic treatment is one of the key factors that determine the outcomes in cases of sepsis . AlthougThis was a descriptive, analytical, retrospective study that was conducted at the ED of Khon Kaen University’s university hospital (Thailand). The inclusion criteria were: Age over 18 years, having presented at the ED with clinical suspicion of infection as diagnosed by the emergency physician, having provided at least two sets of blood cultures, and infection with a bacterial pathogen. Patients with a history of antibiotic administration or with contaminated/non-bacterial pathogens were excluded. This study was a part of the SEPSIS project at Khon Kaen University’s ED. Patients were enrolled between January and July, 2018. The study protocol was approved by the ethics committee in human research, Khon Kaen University, Thailand (HE611518).The pathogen was identified by positive blood culture with a similar pathogen for at least one sample with clinical relevance, while contaminated pathogens were those without clinical relevance. Eligible patients were divided into two groups: Those who were given appropriate antibiotic treatment and those whose antibiotic treatment was inappropriate. Patients allocated to the appropriate antibiotic group were those in whom the prescribed antibiotic was sensitive to the pathogen, based on an antimicrobial susceptibility test reported by the blood cultures. The charts and emergency medical records of eligible patients were reviewed retrospectively. Baseline clinical characteristics and clinical outcomes were evaluated. Outcomes included antibiotic treatment within 60 min, mortality rate, intensive care unit (ICU) admission, and length of hospital stay.Sample size calculation: Based on a population proportion estimation with specified absolute precision, the acceptable incidence of appropriate antibiotic administration was 80%. We determined that the required sample size was 246 patients, with a confidence of 95% and a power of 80%.p-value of less than 0.20, based on univariate logistic regression analysis, were included in subsequent multivariate logistic regression analysis. The final model was tested for goodness of fit using the Hosmer–Lemeshow method. Results were presented as adjusted and unadjusted odds ratios  for appropriate antibiotic prescription. Statistical analyses were performed using STATA version 10.1 .Statistical analysis: Descriptive statistics were used to evaluate differences between the two groups. Factors associated with appropriate antibiotic administration were analyzed using univariate and multivariate logistic regression analysis. Clinically relevant factors or those with a n = 2674), contaminated blood culture results (n = 80), or fungal infection (n = 2), leaving 271 to undergo analysis. The three most common sources of infection were urinary tract infection (20.30%), biliary tract infection (16.97%), and primary bacteremia (16.61%), as shown in Escherichia coli was the most common pathogen (33.21%).A total of 3133 patients who met the study criteria presented at the ED during the study period. Of those, 2862 were excluded due to negative hemoculture , and patients in the appropriate antibiotic group had significantly higher body temperature . However, only pulse rate was an independent factor for appropriate antibiotic treatment after adjusting for other factors, as shown in p-value = 0.157).Forty-eight of the patients enrolled (17.71%) received inappropriate antibiotic prescriptions . There wp-value = 0.022) than the appropriate antibiotic group and hospital admission of greater than or equal to seven days  . In terms of clinical outcomes, the inappropriate antibiotic group had higher proportions of 28-day mortality  . The medThe prevalence of inappropriate antibiotic prescription at the ED was 17.71%, which was comparable with that found in another study conducted at Massachusetts General Hospital in the United States (18%) , but lowp-value = 0.02). In this study, for each 10-beat increase in pulse rate, the risk of inappropriate antibiotic administration went up by 19%  and the 28-day mortality rate (29.17%). Although delayed antibiotic administration can result in poor outcomes , these rThe main strength of this study is that most of the patients enrolled (189/271) were likely to have sepsis. Approximately 70% of patients had a qSOFA score that met the criteria of sepsis, as shown in Inappropriate antibiotics were prescribed in 17% of bacteremia patients presenting at the ED. High pulse rate was an indicator for appropriate antibiotic prescription. Patients presenting at the ED with clinical suspicion of infection and positive blood culture who underwent inappropriate antibiotic administration had longer hospitalization and higher 28-day mortality than those who received appropriate antibiotic treatment.


The waste in the perishable goods supply-chain has prompted many global organizations , to develop the Hazard Analysis and Critical Control Points (HACCP) protocol that ensures a high degree of food quality, minimizing the losses in all the stages of the farm-to-fork chain. It has been proven that good warehouse management practices improve the average life of perishable goods. The advances in wireless sensors network (WSN) technology offers the possibility of a “smart” storage organization. In this paper, a low cost reprogrammable WSN-based architecture for functional warehouse management is proposed. The management is based on the continuous monitoring of environmental parameters , and on their combination to extract a spatial real-time prediction of the product shelf life. For each product, the quality decay is computed by using a 1st order kinetic Arrhenius model to the whole storage site area. It strives to identify, in a way compatible with the other products’ shelf lives, the position within the warehouse that maximizes the food expiration date. The shelf life computing and the “first-expired first-out” logistic problem are entrusted to a Raspberry Pi-based central unit, which manages a set of automated pallet transporters for the displacement of products, according to the computed shelf lives. The management unit supports several commercial light/temperature/humidity sensor solutions, implementing ZigBee, Bluetooth and HTTP-request interfaces. A proof of concept of the presented pro-active WSN-based architecture is also shown. Comparing the proposed monitoring system for the storage of e.g., agricultural products, with a typical one, the experimental results show an improvement of the expected expiration date of about 1.2 ± 0.5 days, for each pallet, when placed in a non-refrigerated environment. In order to stress the versatility of the WSN solution, a section is dedicated to the implemented system user interfaces that highlight detecting critical situations and allow timely automatic or human interventions, minimizing the latter. About 1.3 billion tons of food  and $35 billion per year (in the US) , legislaIn this context, shelf life (SL) has become a pillar concept to describe the current state of product quality, as stated in its definition provided by the Institute of Food Science and Technology: “the period of time under defined conditions of storage, after manufacture or packing for which a food product will remain safe and be fit for use” .There are several predictive SL models ,6, whichBy combining the environmental real-time monitoring capability of the Wireless Sensor Networks (WSN) with the integration, on portable devices and platforms, of predictive SL models, it becomes possible to detect interruptions in the cold chain, and act in advance to compensate abnormal SL failure ,7.Continuous monitoring of the goods, with the possibility to follow the pallets during the transit.Implementation of a specific pallet’s SL prediction model extended all over the storage site. It guarantees the identification of the storage location, inside the warehouse, that optimizes the specific SL. Integration on the central control unit of a Quality Controlled Logistic (QCL) algorithm. It implements a first-to-expire first-out (FEFO) warehouse management .Pallets’ automatic displacement according to the SL prediction model and QCL algorithm outcomes.Easy re-programmability of the platform by in loco operations or by remote actions.Low cost, easy installation and operation.In this paper, a WSN-based architecture for the real-time environmental monitoring and the fully automatic management of pallets in a smart storage site for agricultural products  is detailed. The proposed architecture addresses, together, a number of still unsolved challenges  such as:The monitoring and the management of the automated warehouse are based on the continuous acquisition of the key environmental parameters: temperature (T), light exposure (L) and relative humidity (H). Then, a monitoring algorithm has been developed based on the product quality degradation via a 1st order kinetic Arrhenius model. The algorithm identifies, compatibly with the other products’ SL, the position that maximizes the food expiration, preparing the system for the FEFO logistic problem.The SL computing, as well as the sensor interfacing, are realized on a Raspberry Pi 2 B+ (RPi) that represents the central control unit. Through a set of Python scripts, the unit analyzes the shelf lives and manages a set of automated robots for product displacement, maximizing the SL of each single product.The RPi-based system has been designed to support several commercial light/temperature/humidity (L/T/H) sensors solutions, implementing Zigbee, Bluetooth and HTTP-request communication protocols.The paper is structured as follows: The advances in the WSN technology concerning the number of manageable sensing nodes, as well as the power consumption optimization for sensor systems (continuous monitoring), jointly with the cost reduction of coordination platforms  have led to several literature works in the context of reliable monitoring of perishable goods ,13,14,15To collect the data, the system exploits a tree-topology ZigBee-based WSN with 20 sensor nodes, five router nodes, and one coordinator (sink node) placed in the greenhouse. The system integrates a GPRS module connected with the coordinator via a RS-232 serial port to transmit the received data to the monitoring center. A web-based management subsystem to acquire and analyze the data via the Internet completes the architecture. In , an IoT The Central Control unit consists of a Raspberry Pi 2 B+ working with Raspbian Jessie. It is equipped with an ATmega256RFR2 , for the ZigBee communication and an HC-05 for the Bluetooth interfacing. The RPi implements a set of Python 2.7 scripts for the SL computing, FEFO management and automated robot dispositions. This unit is the core of the system and it is able to interact with each single secondary unit.The Environmental Monitoring Unit consists of L/H/T sensors that acquire statically the data from a specific position of the storage room, sending them to the Central Unit via ZigBee. The Central Unit uses these data to realize a heat map of the storage site.The Storage Unit is composed of the pallet to be monitored and a dedicated L/H/T node placed on the surface. It communicates via ZigBee with the Central Unit. The dedicated node is used to precisely define the product shelf life, because the use of parameters derived mathematically from the Environmental Monitoring Unit, can lead to an avoidable propagation of errors .The Central Control Unit collects data from the Storage and Environmental Monitoring units and implements a predictive SL computing on the chosen pallet. The calculation, repeated on each available position, is useful to identify the optimal site for a specific pallet. Once this place is identified, the control unit opens a Bluetooth communication channel with a dedicated pallet transporter  asking for intervention.As a proof of concept, the WSN-based monitoring and management system has been implemented in a real-life context by using ten ZigBee nodes, equipped with temperature, relative humidity and light exposition sensors. Two of these were applied on the pallet to be monitored . A dedicated and easy reprogrammable (via USB) script was uploaded on the ATmega328 microcontroller, containing the servomotors direction for the steering (PWM management) and the DC motor activation, depending of the tasks provided by the Central Control Unit. Even if in the areas in which the automated robots operate, no obstacles are typically present, the automatons are equipped with ultrasonic sensors , to avoid crashes with human components or pallets out of their correct place.The chosen L/H/T sensor consists of an NXP JN5164 microcontroller  interfacing a 10-bit resolution ADC, for sensor data and digitization, and a Digi XBee 802.15.4 RF module for ZigBee protocol data transmission.The ZigBee protocol is preferable respect e.g., Bluetooth, when the primary importance specifications concern: (i) the low power consumption , (ii) the number of nodes to be monitored , (iii) the flexibility in the network topology ,17,18,19Each sensor node uses three 1.5 AA batteries and, complete of a plastic shell, has the size: 6.85 cm × 6.35 cm × 3.30 cm for a total weight of 160 g. The transmitting power stays under 1 mW, allowing the node to be powered for 1.5 years if the read-sleep cycle is: 1 reading/30 s, and 2.5 years if read-sleep cycle is: 1 reading/60 s.Finally, an adaptive calibration process has been done on the temperature readings, identifying a measures-based correction factor variable around −4 °C, matching the sensor producer reading guidelines . Table 1Three main communication networks have realized the proof of concept for the proposed architecture as sketched in The Environmental Control Unit is managed through a multipoint ZigBee-based network .In this context, it has been proven ,20 that A number of literature studies ,15,16,17k of a reaction with the absolute temperature T, through the following equation:The empirical law ,22 that ref: k value at the dedicated reference temperature Tref.Since the Arrhenius law parameters are typically determined with non-linear regression of empirical data, such as the one in ,21,22, iAccording to  for climFor this reason, this proof of concept bases its functioning on the tomatoes’ firmness as the only parameter for the quality level determination . HoweverIn the firmness evaluation context, the extracted data, analyzed in the following, were inspired to the standardized measurements in , where t0 is the initial quality value, ceq is the quality factor at a specific equilibrium value, t is the storage time and k is the rate determined by Equation (2).A first order approximation about the product quality is given by Equation (3):Then, known a specific quality factor c′ at a given time t, the SL can be calculated as:Together, Equations (2)–(4), allow calculating the products’ remaining life, estimating with a first order model its degradation in the presence of temperature changes. A compendium of the parameters implemented in the proposed monitoring system, extracted tomatoes-centred studies ,21,22, aThe initial shelf life, imposed by the kinetic parameters in The model used to describe a food quality parameter, such as the firmness, is generic and remains valid for every kind of product and quality parameter . The only difference concerns the empirically derived kinetic parameters, which characterize the specific product.−(T1) and k+(T2) with T1 = T + 2 °C and T2 = T − 2 °C. For the same reason, the SL ranges between SL−(k(T1)) and SL+(k(T2)) according to Equations (3) and (4).It is notable that the implemented prediction model exhibits a certain degree of approximation, showing a linear degradation of the SL. Since the temperature sensors shows an accuracy of ±2 °C, the degradation rate k can assume, according to the Equations (1) and (2), values between kref , virtually divided into a 5 × 5 lattice. The eight L/H/T sensors described in 1 = 6.3 m, while the y-axis on the wall with length l2 = 6.7 m. Annotating the sensors coordinates in the form Sn, with n the ID of the specific sensor, the monitoring nodes are placed in: S1, S2, S3, S4, S5 , S6, S7, S8. The internal room heat-map has been derived following the procedure in Considering a top view of the room such as the one in Since the internal room heat-map is mathematically derived by an average procedure described in For this aim, a section of the room was divided in a 3 × 3 lattice and two setups were realized, as shown by The assessment of the absolute temperature error (ε) was done according to Equation (5):Numerical evolution panel, which reports in real-time the SL, quality (C), temperature and information about the displacement aChart of SL in some selected positions ,  … ), for a specific pallet , as shown in A gnuplot panel c that al*ID Connect Port*/lth_sensor_' + i + '/temperature.json'>>string_T='http://devicecloud.digi.com/ws/DataStream/dia/channel/auth=)>>T=requests.get, and the yellow one represents the door of the room.For the validation of the proposed WSN-based system, the testing room has been monitored for about 10 days and 11 h. The placement of the environmental sensors inside the room is sketched in Control loop. Typical profiles of temperature and RH readings during a span of 24 h are shown in QCL Algorithm and SL monitoring. For the QCL algorithm validation, four pallets have been initially placed at the coordinates reported in The proposed algorithm intervenes on the pallets positions by SL priority-based movements as described in The last column of the In this paper, an automated infrastructure for perishable goods supply chain monitoring and their functional management has been presented. It exploits wireless sensor network technologies for goods monitoring and a parallel “real-time” processing for the shelf life prediction and maximization. The low cost of the overall platform and its easy implementation offer a suitable solution for continuous monitoring of the goods, from the farm to the fork, opening to the possibility of packaging monitoring also during the transit. Indeed, e.g., RPi Central Control Unit can manage only a certain number of pallets, and it can be made mobile and transportable, in order to follow the pallets along the whole supply chain.Moreover, the proposed system offers an effective tool for the reduction of the waste and losses in the supply chain by the integration of Quality Controlled Logistic algorithm that ensures the maximization of the product shelf life and manages the first-to-expire first-out stack. The recorded improvements on agriculture products management show an increment of about 1.2 days (15% of maximum product useful life) of the expected expiration date. In the context of pallets management, the proposed proof of concept showed the logic network for the complete management of autonomous transporters, here based on low-cost platforms.The re-programmability of the Central Control Unit allows one to implement more complex shelf-life prediction methods, or simply to modify the kinetics parameters in


Antimicrobial overuse and misuse of broad-spectrum antibiotics increases the risk for antimicrobial resistance. Investigating unwarranted variation in antibiotic prescription has therefore gained global priority.We examined recent time trends in the utilization of narrow- and broad-spectrum antibiotics as well as the variation in antibiotic use by sex, age, and municipality of residence. Complete individual-level data on all redeemed out-of hospital prescriptions for antibiotics in the entire adult population of Central Denmark (1.3 million inhabitants) was obtained for the period 2006–2015.Following an initial increase of 2% between 2006 and 2011, the overall rate of redeemed prescriptions for antibiotics per 1000 person years declined by 17% between 2011 and 2015. Among persons aged over 65 years, the decline in use began later (from 2013) and was less pronounced. Antibiotic use in 2015 remained substantially higher among females (289/1000 person-years) vs. males (182/1000 person-years) and among the very old (520/1000 person-years in >85y old) vs. middle-aged (204/1000 person-years in 45-65y old). A decreasing trend in antibiotic use over time was observed in all municipalities, mainly due to a decrease in narrow-spectrum antibiotics. However, a striking and unexplained 1.6-fold geographical variation in antibiotic use, including tetracyclines, macrolides and fluoroquinolones remained in 2015. Of concern, among females aged ≥65 years and males aged ≥85 years, a continuous increasing trend in broad-spectrum antibiotic use was observed.Antibiotic use has decreased almost 20% in Central Denmark after 2011, possibly related to a nationwide antibiotic stewardship program in Denmark. However, substantial geographical variation in antibiotic prescription remains and the use of broad-spectrum antibiotics has increased in adults of older age. Continuous focus on avoiding unnecessary use of broad-spectrum antibiotics is requested.The online version of this article (10.1186/s12879-019-3964-9) contains supplementary material, which is available to authorized users. Healthcare systems worldwide face the threat of antibiotic resistance, rendering patients at risk of ineffective treatment and increasing healthcare costs. Antimicrobial overuse and misuse is an important risk factor for antimicrobial resistance and appropriate antibiotic prescribing behavior is consequently important to ensure patient safety and quality of care –4. HowevStudies on antibiotic utilization in the European countries have shown increasing overall antibiotic prescribing rates during the early 2000s, while the prescribing rates apparently decreased in the United States from 2006 to 2010 , 8, 11. In 2012, after the total consumption of antibiotics in humans had steadily increased throughout the 2000s in Denmark, the national Danish Health Authorities published “Guidelines on prescribing antibiotics for physicians and others in Denmark” . The natUnlike most countries, the availability of population-based community pharmacy prescription data at the individual person level in Denmark makes it possible to investigate not only time trends in overall antibiotic utilization, but also use of individual antibiotic prescriptions, including their dose and treatment duration, by patient sex, age group, and geographical residence. We therefore conducted a population-based drug utilization study to examine changes in antibiotic prescribing within the last decade including particular types of antibiotics in relation to age, sex and municipality.We conducted a population-based cohort study among all inhabitants above 15 years living in Central Denmark Region from 2006 to 2015. The Central Denmark Region is one of five regions in Denmark, which covers both urban and rural areas. The region has 1.3 million inhabitants, corresponding to 23% of the Danish population . The popThe Danish Civil Registration System was used to identify cohort of inhabitants above 15 years living in Central Denmark Region. The Danish Civil Registration System contains electronic records on vital status , and place of residence for the entire Danish population since 1968, which allow us to keep track of the inhabitants included. The registry is updated daily .The Danish National Health Service Prescription Database was used to obtain data on antibiotic use. The database contains complete data on all reimbursed prescription medications dispensed from community pharmacies . The druUse of antibiotics was defined, as antibiotic for systemic use including all drugs within Anatomical Therapeutic Chemical (ATC)-group J01. Data was aggregated at the level of active chemical substance using ATC classification. We dived the use of antibiotics into tetracyclines (J01A), amphenicols (J01B), beta-lactam antibacterial penicillins (J01C), cephalosporins (J01D), trimethoprim and sulphonamides (J01E), macrolides and lincosamides (J01F), aminoglycosides (J01G), quinolones (J01 M) and other antibacterials (J01X).We calculated the annual prescribing rates of antibiotic use per 1000 person-years calculated as the number of inhabitants who filled at least one antibiotic prescription divided by the total cumulated person time in the observation year and multiplied by 1000. We presented the prescribing rates of antibiotic use stratified for sex and age group . We also estimated the volume of antibiotic use as Defined Daily Dose (DDD) per 1000 inhabitants per day as overall and stratified for sex and age. Furthermore, we investigated temporal trends 2006–2016 in both prescribing rates and volume of antibiotic use. To investigate intra-regional differences in the use of antibiotics, we estimated sex and age standardized prescribing rates of antibiotic use, and age and sex standardized volume of antibiotic use (DDD per 1000 inhabitants per day) by each municipality in the region stratified by year. The standardization was performed in relation to data from the entire Central Denmark Region in 2006.We repeated the analyses for narrow- and broad-spectrum antibiotics separately. Narrow spectrum antibiotics were defined as beta-lactamase sensitive penicillins (J01 CE), beta-lactamase resistant penicillins (J01CF), first-generation cephalosporins (J01DB), and macrolides (J01FA01). Broad-spectrum antibiotics included combinations of penicillins including beta-lactamase inhibitors (J01CR), penicillins with extended spectrum (J01CA), second-generation cephalosporins (J01 DC), third-generation cephalosporins (J01DD), macrolides, lincosamides and streptogramins (J01F). We also investigated the use of each of the following classes of antibiotics: Tetracyclines (J01AA), penicillins with extended spectrum (J01CA), beta-lactamase sensitive penicillins (J01 CE), beta-lactamase resistant penicillins (J01CF), combinations of penicillins including beta-lactamase inhibitors (J01CR), trimethoprim and sulphonamides (J01E), macrolides, lincosamides and streptogramins (J01F), fluoroquinolones (J01MA), metronidazol  and other antibacterials (J01X). We calculated both antibiotic prescribing rates and volume of antibiotic use (DDD per 1000 inhabitants per day) of the subgroups of antibiotics.Additionally, we examined the subgroups of antibiotics within the municipalities and calculated the mean duration of antibiotic use per prescription by adding the total days of antibiotic exposure (DDD*packsize) divided by the total number of prescriptions retrieved for the calendar year 2015.All analyses were performed using SAS version 9.4.The overall age and sex standardized prescribing rates of antibiotic use in Central Denmark Region increased slightly from 285/1000 person-years in 2006 to 290/1000 person-years in 2011 after which the antibiotic prescribing rates decreased to 236/1000 person-years in 2015. Figure When estimating the volume of antibiotic, we saw a similar picture with decrease in overall volume of antibiotics from 5589 DDD/1000 persons in 2011 to 4709 DDD/1000 persons in 2015 , and penicillins with extended spectrum (J01CA) Fig. . The use CE, and Differences in the age and sex standardized volume of different antibiotics were also observed between the municipalities  and was less pronounced in the older age groups, whereas a similar decline was seen for both sexes. However, the pattern of much higher antibiotic use in females versus males, and among older versus younger people has remained also in the most recent years. The overall use of narrow-spectrum antibiotics decreased substantially over the years, while the prescribing rates of broad-spectrum antibiotic use first declined from 2011 onwards. Of concern, among females aged ≥65 years and males aged ≥85 years a continuously increasing trend in broad-spectrum antibiotic use was observed from 2006 to 2015, primarily related to increasing use of combinations of penicillins including beta-lactamase inhibitors. There was a clear decline in antibiotic use in all municipalities over time, although striking geographical differences remained in antibiotic use in 2015 that were not explained by age and sex differences.Clostridium difficile colitis, interactions with other medications in those with polypharmacy, or risk of treatment-induced cognitive disturbances [Our results regarding the notably high antibiotic use among older persons match those observed in earlier studies from Denmark and United States, , 26, 27.urbances –30.The overall prescribing rates of antibiotic use were relatively stable from 2006 to 2011, however when we examined prescribing rates according to narrow- and broad spectrum antibiotics a different picture was seen Fig. , as the .The increase in use of broader spectrum antibiotics is worrying as their use is related to resistance and adverse drug events including gastrointestinal disturbances, secondary infections (including yeast and C difficile infections), nephrotoxicity, neurological or psychiatric effects, sensory or motor disturbances, and allergic reactions . OccurreWithin the broad-spectrum antibiotics, a large increase was observed for the combination penicillins with beta-lactamase inhibitors, in particular among older people. One could speculate that this may be related to changes in regional and national recommendations for treatment of moderate exacerbations in patients with chronic obstructive pulmonary disease (COPD) in 2007, where amoxicillin with clavulanic acid became a first line drug in Denmark instead of narrow-spectrum penicillins . DenmarkA major strength of this study is the use of complete individual-level prescription drugs bought at monopolized community pharmacies. All antimicrobial agents in Denmark can be bought as prescription medication only and redeemed prescriptions will therefore be a truthful reflection of the actual utilization out of hospitals. Our study also has some limitations. The study was restricted to Central Denmark Region, but the homogeneity of the Danish Healthcare System makes it likely that our results can be generalized to the four other regions in Denmark . MoreoveOur data show that there is room for improvement in antibiotic prescribing. The decrease in overall antibiotic use mainly stems from a decrease in narrow-spectrum antibiotics, which in general should be the preferred antibiotics due to lower risk of transmissible resistance development in bacteria. The very large increase observed for use of combinations of penicillins with beta-lactamase inhibitors is worrying and tailored interventions for reducing the use is needed. Furthermore, there remains huge variation between Danish municipalities in the use of critical antibiotics including tetracyclines, macrolides and fluoroquinolones. The fast trends in use of individual antibiotics and the huge variation between Danish municipalities may suggest that the use of antibiotics could be moved by safety concerns or market factors including pricing, availability and advertising rather than current guidelines , 36. IncThis study provides evidence for substantially decreasing prescribing rates for antibiotics in Central Denmark after 2011. At the same time, the use of broad-spectrum antibiotics has increased and now for the first time surpasses the use of narrow-spectrum antibiotics in Denmark.Additional file 1:Table S2. shows volume of antibiotics DDD per 1000 person-years from 2006 to 2015 according to sex and age groups. Table S3 shows volume of narrow- and broad-spectrum antibiotics DDD per 1000 person-years from 2006 to 2015, stratified by sex and age group and Table S4 shows age and sex standardized volume of subgroup of antibiotics, stratified by the municipalities in Central Denmark Region in 2015. Furthermore the file contains Figures S7 and S8, which shows prescribing rates and volume of antibiotic per 1000 person-years from 2006 to 2015, stratified by sex and age group. (DOCX 1211 kb)


Urinary tract infection (UTI) is common in primary care and leads to a high number of antibiotic prescriptions. Antimicrobial resistance is a global health problem; better antimicrobial prescribing is one way to limit antimicrobial resistance. We aimed to describe the number of consultations for patients diagnosed with lower urinary tract infection (LUTI) and pyelonephritis and changes in prescribing of antibiotics to men and women with LUTI and pyelonephritis in Swedish PHC between the years 2008 and 2013.We performed a descriptive study of changes in UTI diagnosis and antibiotic prescribing in UTI for the years 2008, 2010 and 2013. The Primary Care Record of Infections in Sweden, a database regarding diagnosis linked antibiotic prescribing in primary care, was analyzed concerning data for men and women of all ages regarding UTI visits and antibiotic prescribing. The results were analyzed in relation to current national guidelines.There was a variability in consultation incidence for LUTI with an increase between 2008 and 2010 and a decrease between 2010 and 2013, resulting in a slight rise in consultation incidence between 2008 and 2013. The use of recommended nitrofurantoin or pivmecillinam in LUTI in women increased from 54% in 2008 to 69% in 2013. Fluoroquinolones or trimethoprim were prescribed in 24% of LUTI cases in women in 2008 and in 7% of cases in 2013. Prescriptions of pivmecillinam or nitrofurantoin in male LUTI cases increased from 13% in 2008 to 31% in 2013. Fluoroquinolones or trimethoprim were prescribed in 54% of male LUTI cases in 2008 and 32% in 2013.Swedish GPs seem to follow national guidelines in the treatment of LUTI in women. In male LUTI cases, the prescriptions of fluoroquinolones remain high and further research is needed to follow prescription patterns and enhance more prudent prescribing to this group of patients. Escherichia coli and this was one of the reasons behind the revised recommendations for the treatment of lower urinary tract infection (LUTI) in women, which were published in 2007 and for men in 2014 [The increasing frequency of bacteria resistant to antibiotics is a global health problem. Inappropriate use of antibiotics favors the emergence and selection of resistant bacterial strains . In gene in 2014 . Pivmeci in 2014 . The tot in 2014 .In Swedish primary health care (PHC), LUTI is the greatest cause of antibiotic prescribing . Among wAcute pyelonephritis is far less common than LUTI. The incidence of pyelonephritis is highest among young women, followed by infants and elderly people. The annual rates of outpatient pyelonephritis were 12–13 cases in women and 2–3 cases in men per 10,000 respectively .Using large diagnosis linked prescribing registers, trends in antibiotic prescribing in primary care in the UK during 1995–2011 and in the Netherlands during 2007–10 have been described, , 11 or iWe aimed to describe the number of consultations for patients diagnosed with LUTI and pyelonephritis and changes in prescribing of antibiotics to men and women with LUTI and pyelonephritis in Swedish PHC between the years 2008 and 2013.This retrospective descriptive study was based on information from the PRIS record for the years 2008, 2010 and 2013.To evaluate the prescribing rate and the adherence to clinical guidelines, the PRIS record (Primary Care Record of Infections in Sweden) was created by the Unit of Research and development (R&D) in Primary Care in Jönköping in 2007. The PRIS record consists of diagnosis based data and uses information from medical records from patients in primary health care., 13 The st for the respective year.Primary Health Care Centers (PHCCs) from all parts of Sweden were invited each year to report patient data on all infectious diagnoses to the PRIS record. In Sweden, general practitioners (GP) work in primary health care and a full time GP handles 1500–2000 registered persons. The inhabitants are encouraged to register with any public or private PHCC within their region. In 2008 a total of 47 PHCCs with 460,529 registered persons were included in the PRIS register. An increasing number of PHCCs subsequently joined the PRIS register and in 2013 a total of 88 PHCCs with 785, 070 registered persons were included. Included PHCC were both small and large units, private and public, situated in rural and urban areas in all parts of Sweden. The number of registered persons in the PRIS record in 2013 represented 8% of Sweden’s population. The ages for the patients included in the study was known but the age distribution of all registered persons was not known. Due to the large number of registered persons in the material, the age- distribution of total registered persons for all included PHCC was assumed to correspond to the age-distribution of the total inhabitants of Sweden as of December 31All visits during office hours that resulted in a diagnosis of infection were registered according to the International Classification of Disease and Related Health Problems-Tenth Revision (ICD-10) introduced by the World Health Organization (WHO). Prescribed antibiotics were registered according to the Anatomical Therapeutic Classification System (ATC). The ATC-coding system is used to classify drugs in order to facilitate studies on drug-use in Sweden . FurtherPRIS-data from the years 2008, 2010 and 2013 were analyzed focusing on visits related to UTI. Inclusion criteria were a diagnosis classified as UTI . For eacIncluded patients were stratified into age-groups. The incidence of UTI and prescribed antibiotics was described by age group 0–15, 16–30, 31–50, 51–70, 71- years. The same age-groups were used in both men and women. Intervals in age-groups were not equal in size but were defined according to the following: children, young adults, adults, older alduts and elderly. Calculations on incidence of UTI per 1000 registered person and year for men and women in each age group were based on figures on age distribution in Sweden from Statistics Sweden for the actual years [Percentage of consultations due to infections, prescribed antibiotics and prescribing rate from the 37 PHCCs that participated all investigated years  were analyzed separately and compared to that of all included PHCCs. This sensitivity analysis was published by Tyrstrup et al . FurtherP-values ≤ 0.05 were considered statistically significant. We reported 95% confidence intervals for ratios, assuming a normal distribution.The data collected in the study were analyzed using Excel  and SPSS Statistics 22 . Data were mainly descriptive with numbers and frequencies presented in tables. Differences between groups were tested using the two-sided Chi-square test for categorical variables (CHISQ.TEST function of Microsoft Excel). Confidentiality for patients was ensured by using a one-way encrypted ID-number. The study was approved by the Regional Ethical Review Board in Linköping, Sweden, for the PRIS register. (Dnr 2010/227-31).The total number of registered persons and the number of PHCCs included in the PRIS database increased from 2008 to 2013 . ConsultThe number of antibiotic prescriptions to women with LUTI was 60/1000 registered women in 2008, 63/1000 in 2010 and 58/1000 registered women in 2013. The number of women with LUTI linked to an antibiotic prescription, who were prescribed pivmecillinam or nitrofurantoin, increased from 54% in 2008 to 67% in 2010 and to 69% in 2013. The proportion of trimethoprim or fluoroquinolones decreased from 24% in 2008 to 13% in 2010 and to 7.% in 2013 . The numThe number of antibiotic prescriptions to men with LUTI was 7/1000 in 2008, 7/1000 in 2010 and 8/1000 men in 2013.Antibiotic prescriptions to men diagnosed with LUTI are presented in LUTI was not common among men younger than 50 years of age. The frequency of prescriptions for LUTI in men increased with age . The proWomen made up almost three-quarters of visits by patients diagnosed with pyelonephritis. Pyelonephritis was most common among women aged 16–30 years  and among women 51 years and older . Fluoroquinolones were the most common antibiotics prescribed .Visits related to pyelonephritis were uncommon in younger men . The incidence rates increased with age and pyelonephritis was most common in the age-group 71 years and older . Fluoroquinolones were the most commonly prescribed antibiotics .The frequency of prescriptions of antibiotics without a UTI diagnosis in the PRIS database decreased from 21% in 2008 to 15% in 2010 and 14% in 2013. Antibiotic prescriptions with no registered diagnosis could due to prescription of pivmecillinam and nitrofurantoin (that are prescribed to treat UTI exclusively) be allocated to probable UTIs in 31% (2008), 25% (2010) and 36% (2013) of the cases.This register based study on LUTI showed a variability in consultation incidence with an increase between 2008 and 2010 and a decrease between 2010 and 2013, resulting in a slight rise in consultation incidence due to LUTI between 2008 and 2013. The proportion of patients not receiving antibiotic prescription in spite of a diagnosis of LUTI increased, especially in women. In both women and men the number of prescriptions of pivmecillinam and nitrofurantoin increased and the prescriptions of trimethoprim and fluoroquinolones decreased.According to the Swedish treatment recommendations from 2007 the first choice antibiotics for the treatment of LUTI in women were pivmecillinam and nitrofurantoin. Trimethoprim could be used as a second choice antibiotic but only after urinary culture. Prescribers were also recommended to minimize the use of fluoroquinolones , 17. PRIExpert recommendations regarding male LUTI were formally released in 2014. Nitrofurantoin and pivmecillinam are now recommended as first choice antibiotics also in the treatment of LUTI without fever in men , 5, 17.The Swedish strategic programme against antibiotic resistance (STRAMA) recommended that fluoroquinolones should make up less than 10% of UTI antibiotics in women aged 18–79 years . The proThe increased ratio of narrow spectrum antibiotics and a decrease in fluoroquinolones in the treatment of LUTI seen in the present study is positive and one step in the work to decrease the use of fluoroquinolones, which is of importance, since they often promote the development of antimicrobial resistance. We still need to follow prescription patterns in this group of patients and we also have to evaluate the effect of narrower antibiotics in the treatment of LUTI, especially in men where few studies have been done.The bacterial etiology, resistance patterns and national recommendations for antibiotic therapy in LUTI differ between European countries. Treatment recommendations are most likely based on traditions, availability of antibiotics and differences in antimicrobial resistance patterns. In a 2013 article, national recommendations from six European countries were described. Nitrofurantoin and pivmecillinam were the most agreed upon first choice antibiotic treatments for women and were recommended in five and three countries respectively [According to the present study, Swedish GPs show good adherence to clinical recommendations in the treatment of female LUTI. In the UK, diagnosis linked prescribing data were used to describe trends in prescribing of UTI antibiotics in primary care during 1995–2011. The use of recommended short course trimethoprim for UTI in women increased from 8% to 50% between 1995 and 2011 .To implement new recommendations in health services, a wide variety of conditions must be satisfied , 23. ResThe main strengths of the present study are the large number of patients studied and the inclusion of male LUTI. In order to monitor the use of antibiotics in the public health care system, we need register-based diagnosis linked prescribing data. The PRIS register, which has more than half a million infection-related visits, gives us the opportunity to follow changes in antibiotic prescribing and adherence to clinical guidelines over time. Previous studies conducted in Sweden on prescribing in PHC are mainly based on sales data in order to assess whether antibiotics are used adequately; diagnosis linked prescription data from PHC is needed.Previous studies describing trends in antimicrobial prescribing in primary care have not shown data on male LUTI , 10. To The number of PHCCs included in PRIS increased progressively from 2008 to 2013, which may have affected measurements over that period. We did a sensitivity analysis and did not find any difference between the PHCCs that participated all the years and the total PHCCs .One limitation of the study is the possibility that PHCCs interested in participating in the PRIS register may be more interested in quality assessment and more prone to follow clinical guidelines when treating UTI than PHCCs not participating in PRIS. We found many visits registered as UTI or pyelonephritis without prescribing of antibiotics. Considering the serious condition of pyelonephritis this could be alarming. However, we believe that many patients diagnosed with pyelonephritis were referred to the emergency ward and thus not prescribed antibiotics at the PHCC. Furthermore, this could also represent patients revisiting for check-up after the infection.A limitation is that PRIS does not contain information about treatment failure, drug allergies, adverse events from antibiotic treatment or recurrent infections which could interfere with the number of antibiotic prescriptions and the choice of antibiotic in relation to UTI diagnosis.One limitation with register-based studies is that we are dependent on clinicians registering the correct diagnosis when prescribing antibiotics. The clinicians are not obliged to register a diagnosis when prescribing antibiotics and in some cases clinicians may think that antibiotics with only one indication  can replace the need for a diagnostic code. A diagnosis labelling may legitimate an antibiotic prescription in cases where the clinical UTI diagnosis is doubtful. This study found that a diagnosis was often missing when prescribing nitrofurantoin and pivmecillinam, we therefore believe that the incidence of UTI in PHC is higher than described in this study.The major change in prescribing of antibiotics commonly used in the treatment of LUTI among patients in primary health care is in line with the Swedish guidelines published in 2007 for women and in 2014 for men. Swedish GPs follow clinical recommendations in the treatment of LUTI in women. Prescriptions of nitrofurantoin and pivmecillinam in this group increased during the studied period and prescriptions of fluoroquinolones and trimethoprim decreased. In male LUTI patients, the prescriptions of fluoroquinolones and sulfamethoxazole-trimethoprim have decreased but are still high and further research is needed to follow prescribing patterns and enhance more prudent prescribing to this group of patients. It is important to follow changes in antibiotic treatment of infections frequently managed in primary care in order to set treatment goals and monitor adherence to clinical guidelines so as to be able to improve antibiotic management.S1 AppendixList of diagnostic codes for lower urinary tract infection and pyelonephritis.(DOCX)Click here for additional data file.S2 AppendixCharacteristics of the infectious disease dataset and the urinary tract infection dataset.(DOCX)Click here for additional data file.


Glass fiber-reinforced polymers (GFRPs) have received increasing attention in recent years due to their overall performance of light weight, low cost and corrosion resistance, and they are increasingly used as reinforcement in concrete structures. However, GFRP material has low elastic modulus and linear elastic properties compared with steel bars, which introduces different bonding characteristics between bars and concrete. Therefore, a reliable monitoring method is urgently needed to detect the bond slip in GFRP-reinforced concrete structures. In this paper, a piezoceramic-based active sensing approach is proposed and developed to find the debonding between a GFRP bar and the concrete structure. In the proposed method, we utilize PZT (lead zirconate titanate) as two transducers. One acts as an actuator which is buried in the concrete structure, and the other acts as a sensor which is attached to the GFRP bar by taking advantage of machinability of the GRRP material. Both transducers are strategically placed to face each other across from the interface between the GFRP bar and the concrete. The actuator provokes a stress wave that travels through the interface. Meanwhile, the PZT patch that is attached to the GFRP bar is used to detect the propagating stress wave. The bonding condition determines how difficult it is for the stress wave traveling through the interface. The occurrence of a bond slip leads to cracks between the bar and the concrete, which dramatically reduces the energy carried by the stress wave through the interface. In this research, two specimens equipped with the PZT transducers are fabricated, and pull-out tests are conducted. To analyze the active sensing data, we use wavelet packet analysis to compute the energy transferred to the sensing PZT patch throughout the process of debonding. Experimental results illustrate that the proposed method can accurately capture the bond slip between the GFRP bar and the concrete. Corrosion of steel reinforcement embedded in reinforced concrete (RC) is one of the most significant factors limiting the service life of RC structures ,2. It isThere are many nondestructive testing (NDT) and structural health monitoring (SHM) ,18,19 apPiezoceramic material is very versatile and is commonly used in SHM and damage detection ,36,37,38For its effectiveness and simplicity, the piezoceramic-based active sensing method has been proposed and applied for the debonding detection in recent years. Ihn and Chang used active sensing methods for detecting cracks and debonds in metallic and composite structures . MustaphThe piezoceramic-based active sensing method has been used in the detection of the debonding status between concrete and the rebars ,56. HoweThe rest of the paper is organized as follows. Piezoceramic material, as a type of piezoelectric material, has superior properties of low cost, quick response, high reliability, solid-state actuation, wide frequency range and energy harvesting capacity ,58,59. AAn active sensing method ,63,64 usIn this paper, an active sensing technique using piezoceramic transducers is proposed to detect the debonding status of GFRP bars in RC structures. The PZT patch embedded in the GFRP bar is used as a sensor to detect stress waves which are generated from a PZT actuator fixed in the concrete specimen cube. The detecting principle is illustrated in A pull-out test is used to cause the damage between the GFRP bar and the concrete specimen. When a bond slip happens, with the appearance of the internally cracked zone shown in b, which Wavelet packet analysis is an effective method for signal processing which has been widely used in structural health monitoring ,66,67,68j represents the decomposed wavelet packets. With the wavelet packet-based method, the severity of bond slip can be analyzed based on the total energy of the received signal.Wavelet packet analysis is an excellent signal-processing tool which has been widely used to extract damage features. In this paper, we use Wavelet Toolbox provided by MATLAB to compute the total energy of the signal. The energy of each wavelet packet The design of the specimen with the PZT-enabled active sensing approach is shown in 3 in size working as sensor is embedded in the GFRP bar by taking advantage of the machinability of the GFRP. With this special design, a recess that matches the dimension of the PZT patch is processed, and then the PZT patch is placed in the recess with a thin layer of epoxy. In this way, the original shape of the GFRP bar is restored. Both transducers are strategically placed across from the interface to best monitor the interface condition via the active sensing approach. A bond slip between the GFRP bar and the concrete introduces a crack along the interface and adversely impacts the stress wave propagation across the interface.As shown in The length and diameter of the GFRP bar are 560 mm and 20 mm, respectively, and the tensile strength and the modulus of elasticity of the GFRP bar are 83 MPa and 72 GPa, respectively. Each specimen has the dimensions of 200 mm × 200 mm × 200 mm. The strength of the concrete is 35 MPa. Two specimens are fabricated, and As shown in The pull-out test schematic is shown in The instrument system, as shown in Experiment 1.The specimen is the one with the 5D length of GFRP bar. The loading rate is 0.5 mm/min. The experiment lasted 18 min and 30 s.Experiment 2.The specimen is the one with the 4D length of GFRP bar. The loading rate is 0.3 mm/min. The experiment lasted 32 min and 5 s.In this experimental test, the loads and the extensions applied on the specimen are controlled by the universal material test machine. Please note that in this research two experiments that involved two different specimens are conducted via pull-out tests. Both experiments are conducted under the displacement control mode. For both the strain gauge and PZT-enabled active sensing, the data are collected every 5 s. During both experiments, a bond slip is often accompanied by a loud sound. The experiment will be terminated if a sharp drop in the loading time history is observed.The BPE model, which is named after Bertero, Popov and Eligehausen, is generally used to describe the bond slip of a steel bar in concrete . CosenzaWe conduct both experiments by following the procedures described in At the beginning of the loading process, the strain of the GFRP bar (black line) increases with the load until 14.3 min, after which the strain starts to decrease as shown in The strain gauge which is bonded on the surface of the GFRP through the epoxy is used to measure the local strain of the GFRP. The bonding condition changes during the loading process, which adds uncertainty to the strain monitoring. In addition, the strain gauge can only measure the strain in a small localized area. Therefore, it is difficult to effectively detect the bond slip between the GFRP bar and the concrete by using the strain value.Also from Similar results are also observed in experiment 2 with the second specimen. In this experiment, only a single major bond slip is observed, which is verified by both the energy reading of the PZT-enabled active sensing and the strain gauge. The failed specimen is shown in In this paper, a PZT-enabled active sensing technique was proposed and implemented to detect the bonding slip between a GFRP bar and RC structure. Two PZT transducers were employed: one in the form of a piezoceramic smart aggregate and the other in the form of a patch. Both transducers were strategically placed to face each other across from the interface between the GFRP bar and the concrete. A piezoceramic smart aggregate working as actuator was buried in the concrete to generate a stress wave that propagated and traveled through the interface. Meanwhile, the PZT patch that was embedded in the GFRP bar worked as sensor to detect the arriving stress wave. The bonding condition determines how the stress wave travels through the interface. The occurrence of a bond slip introduced a crack between the bar and the concrete, and dramatically reduced the energy the stress wave carried through the interface. In this research, two specimens were fabricated and two pull-out tests were conducted. The experimental pull-out test results demonstrated that the PZT-enabled active sensing approach could accurately capture the bond slip between a GFRP bar and concrete. The energy metric based on wavelet packet analysis can indicate the bond slip occurrence as the energy of arriving stress wave significantly drops. This active sensing technique provides a reliable real-time debonding damage monitoring method for GFRP-reinforced concrete structures.


The idea of sustainable development assumes that natural resources must be treated as limited goods and that waste must be managed rationally. This idea and the constant striving to reduce production costs make the use of waste materials as substitutes for traditionally used raw materials from non-renewable sources increasingly popular. In cement concrete technology, there are many possibilities to use waste as components of mortars and concretes. The subject of this paper is a fine-grained material, obtained as a by-product during the preparation of aggregate for mineral-asphalt mixtures. The aim of the research was to test the suitability of the selected type of powder, namely limestone powder, as a component of cement composites. The paper presents an evaluation of the potential of using the limestone powder as a substitute for the fine aggregate, focusing on the impact of such a modification on aspects of durability. The sulfate degradation and chloride ion diffusion in concrete were investigated. The overall desirability function has been determined. It was demonstrated that the satisfactory value of the general desirability can be attributed to most of the investigated concretes. Positive test results support the potential of replacing part of natural fine aggregate with the tested waste limestone dust without a negative impact on the durability of concrete. The idea of sustainable development assumes that natural resources should be treated as limited goods and the wastes should be rationally managed. Increasing amounts of collected waste, up to 2500 million tonnes per year over the world  encouragThe modern engineering of building materials enables significant modification of the composites used in construction. New directions of research on the building materials include, among others, the waste management issues. The assumptions for these strategies and the constant striving to reduce production costs make the use of the waste materials as the substitutes for traditional raw materials from non-renewable sources increasingly important.In cement concrete technology there are many possibilities of using wastes as components of mortars and concretes . The wasProduction of cement . The initial stage of HMA production is drying combined with aggregate dedusting. As a result of this process, large amount of mineral dust is accumulated in the filters of dryers and temporarily stored in silos. A small part of it is used for the production of HMA. In most cases, however, it is disposed as a filler for excavations or embankments, which definitely do not exhaust the potential of the mineral powder material. What is specific for HMA production is that the obtained waste includes a whole group of materials diversified due to the different raw materials, i.e., the types of rock used in production, as well as the specifics of the production process. Due to the good adhesion of the asphalt binder to the basalt and lime coarse aggregate, they are most frequently used in the production of HMA. Due to technological conditions, the time of aggregate preparation should be constant. Therefore, depending on the humidity and temperature of the prepared aggregate, it is necessary to modify the blowing force and temperature of the dryer, which results in different characteristics of the collected waste.The aim of the article is to present an evaluation of the suitability of a selected type of waste limestone powder as a substitute for the fine aggregate in cement composites, focusing on the impact of such a modification on the properties related to durability.The waste limestone dusts currently used in concrete technology come mainly from the production of aggregates obtained from the rock deposit. An assessment of the impact of this type of waste has been the subject of many publications, including those concerning the durability of concrete.The permeability can be a measure of durability resulting from the resistance of concrete to penetration and movement of aggressive substances, both liquid and gaseous, inside the concrete . TherefoAnother factor related to the durability of concrete is its absorbability. The addition of limestone dust as a partial substitute for sand in the amount of 15% results in a decrease in concrete absorbability ,23. AccoOne of the most aggressive factors causing corrosion of steel in reinforced concrete are chlorides. Uysal et al.  demonstrSulphates are another aggressive factor related to cement concrete. Uysal and Sumer , in ordeStudies on the application of calcium waste dust from the preparation of aggregate in concrete in HMA plants have not been published so far, except for works by Esquinas et al. ,34. The The purpose of the conducted research was to determine the impact of partial substitution of the fine aggregate by the waste limestone powder on the chemical resistance of cement concrete. Concrete samples were prepared according to the experimental design. The prepared samples were subjected to the following tests: compressive strength after 28 days, resistance to chloride ions penetration and resistance to sulfate degradation.3)n  was used as dispersing agent. The concentration of the solution was 0.2%. The ultrasounds were used for 1 minute to break up the potential agglomerates of particles. The obtained specific area for tested powder was 26,444 cm2/cm3. The average diameter was 27.5 μm and the mode diameter was 14.2 μm. The particle size distribution is presented in the The waste limestone powder used in the experiment was obtained from HMA production. The base aggregate used to that production was limestone. The basic properties of the powder are presented in the 3 is 84.85 %wt. Content of SiO2 is 7.06 %wt. and Al2O3 2.38 %wt. . The scanning electron microscope FEI Quanta 250 FEG  was used for current investigation  in the range of 0.35 ÷ 0.55 and the level of sand substitution with the waste powder, expressed as a mass ratio of waste to cement in the range of 0–20% (P/C) which means 0–10.8% of natural sand mass. Due to the planned statistical analysis, a bi-factorial polyseck-rotal-quasiuniformal plan was adopted with a two-fold repetition of the measurement at the central point  36]..36].3. The crushed granite aggregate of the group of fractions 2/16 and river sand were used. The grain size curve was selected according to the standard composition by EN 1766:2001 . An air-entraining admixture in a constant amount of 0.2% of cement mass was applied, as well as a water reducing admixture in a variable amount dosed to obtain a constant consistency of S3 for all mixes.The composition of the reference, unmodified concrete mix  was adopted in accordance with EN 1766:2001. Therefore, the concrete mixes were prepared with the use of a fixed amount of cement CEM I 42.5 R NA HSR amounting to 375 kg/mDeff). It was determined according to EN 13396, using the Fick’s law. Cubic samples of 150 mm side lengths were prepared for testing. The specimens were cured for the first 24 h covered with the plastic sheet and then were stored for 27 days in a climatic chamber . After this time, the specimens were cut in half to open the structure and then protected on each side, with the exception to the cut surface, with an epoxy resin to prevent chloride ions penetration through surfaces other than the tested one. The prepared specimens were placed in 3% NaCl solution made with demineralized water. The samples were positioned so that the test surface was perpendicular to the solution level and the samples were covered with at least 10 mm of solution , mass change (Δm) and appearance of the samples-changes occurring on the surface of the specimens. In order to intensify the corrosive action of sulfates, small cubic samples with a side of 50 mm, formed by cutting the cubic samples with a side of 100 mm, were used. The specimens were cut after 28 days of curing (one day under the plastic sheet and 27 days in water under laboratory conditions). From each composition 24 samples were prepared. A summary of the number of samples to be tested is presented in the The sulfate resistance of cement composites is usually tested as an expansion of beam mortar specimens during exposure on sulfate solution ,40. Prel2SO4 solution, as appropriate. Twelve specimens from each composition were stored in water and twelve in Na2SO4 solution prepared with demineralized water. The concentration of SO42− ions was 10 g/dm3. Both the solution and the water were replaced every two weeks. After three months, the first group of samples was examined. Second group of samples was tested after six months. The specimens were tested according to the The specimens to be tested for mass changes were dried to the constant mass in the oven at 105 °C and then weighed and placed in water or in the NaConducted investigation covered the testing of the compressive strength, resistance to chloride ions penetration and resistance to sulfate degradation. The results are presented in the fc, Deff and ∆fc,6m (compressive strength change after 6 months of storing in sulfate ions solution) and finding the overall desirability function. For the prognostic calculations, StatSoft’s Statistica software was used. The generalized additive models (GAM)  (For the obtained Equation (3) the coefficient of determination was calculated Rd [Cobb] . It coulfc,6m is greater than the effect of P/C in the range of studied values  . As expefc,6m  with the increase in substitution level. In case of concrete with lower W/C, increase of content of waste limestone powder results in decrease in resistance to sulfates at low substitution level and an increase in resistance to sulfate at high substitution levelOn the basis of the conducted research it was found that sand substitution with waste limestone powder results in:Deff measurement is an issue related only to diffusion. It can be assumed that the reduction of capillary dimension in the range greater than the dimension of Cl− ions favours capillary diffusion. In the case of sulphate degradation, the effects of filling pores with corrosion products are the subject of measurement. Smaller capillaries fill faster and prevent the further migration of SO42− ions from the solution, which inhibits the degradation process. This effect is observed only at low W/C ratios, in which the initial capillary size is small. The mechanisms described above explain different conclusions concerning the effect of calcium waste powder on chloride diffusion and sulphate degradation.Both the phenomenon of chlorine contamination of concrete and the phenomenon of sulphate destruction are associated with the diffusion of ions in porous liquid in capillaries. The results of studies on the influence of P/C growth (i.e. increase in the share of limestone powder in concrete) on these two features are different.


The controlled electrodeposition of nanoparticles at the surface of an emulsion droplet offers enticing possibilities in regards to the formation of intricate structures or fine control over the locus or duration of nanoparticle growth. In this work we develop electrochemical control over the spontaneous reduction of aqueous phase Au(III) by heterogeneous electron transfer from decamethylferrocene present in an emulsion droplet – resulting in the growth of nanoparticles. As gold is a highly effective conduit for the passage of electrical current, even on the nanoscale, the deposition significantly enhances the current response for the single electron transfer of decamethylferrocene when acting as a redox indicator. The nanostructures formed at the surface of the emulsion droplets were imaged by cryo‐TEM, providing an insight into the types of structures that may form when stabilised by the interface alone, and how the structures are able to conduct electrons. ΔGorgaqbetween the two phases.Liquid/liquid interfaces have numerous applications in phase separation procedures, sensing, catalysis, and growth or assembly of nanoscale structures. Due to the high surface tension between two immiscible liquids there is a significant energetic benefit to the assembly of nanostructures between the two fluids to reduce the area in contact. Such systems have been observed since early work on the spontaneous deposition of metals or the development of Pickering emulsions.However, it is also possible to control heterogeneous redox reactions at the surface of a Pickering emulsion, including metal reduction protocols.4]−.4]− (1). If a low DMFc concentration is employed, then the species is rapidly depleted,forming DMFc+ within the droplet as the gold is deposited. Under an applied potential, DMFc is instead replenished at the electrode enabling further gold deposition (2). Once the Au0 begins to build up at the surface of the droplet it is able to act as a conduit for the electrons between the electrode and the reducing agent (3). As this process increases the effective surface area of the electrode the current for the DMFc←→DMFc+redox reaction is seen to increase significantly.As shown previously, ferrocene and its derivatives are effective reducing agents for aqueous − is depleted in the aqueous phase, less DMFc is consumed through reduction leading to a more symmetrical CV.The system can be evaluated through cyclic voltammetry. In order to see the initial depletion of the organic phase DMFc through the spontaneous reduction of aqueous −, verifying the applicability to the electrochemical system. Microscope images of the droplets under electrochemical conditions are provided for comparison .Whilst not under electrochemical control, we have been able to image the particles on the surface of an emulsion in situ by cryo‐TEM Figure  and SI. 4]− is consumed from the aqueous phase.When imaging, it was found that the oil droplets would preferentially sit on the carbon film itself, adjacent to the holes in the grid. The arrows in Figure In conclusion, this work demonstrates the possible introduction of electrochemical control to the growth of gold nanoparticles by inhibiting the spontaneous chemical reaction and driving the redox process sequestered within organic droplets attached to an electrode surface. The organic species DMFc acts as both a reducing agent and redox species. A significant increase in current is observed following the deposition of Au which is able to conduct electrons, therefore extending the electrode surface area. If instead there is no direct contact between the 3 phases then the current is reduced through blocking of the interface. The observed increase in electron transfer current is supported by cryo‐TEM which shows extended Au nanostructures on the surface of the droplets. With incisive application of ligands which remove the particles from the surface of the droplets this system may be developed to drive the continuous growth of nanoparticles under electrochemical control.x mM DMFc where x=20 or 100 mM) and background electrolyte  in trifluorotoluene (TFT) was added to an aqueous electrolyte (0.1 M LiClO4) containing y mM HAuCl4 . The phases were shaken for 30 s and the electrodes added. Electrochemical measurements were performed on an Autolab PGSTAT20, using a 3‐electrode set up with a glassy carbon working electrode, coiled Pt counter electrode and Ag/AgCl reference electrode in 1 M KCl. Cryo‐TEM was performed on a FEI Tecnai Spirit G2 BioTWIN TEM using a Gatan 626 cryogenic sample holder at −179 °C. Complete experimental details are provided within the SI.To form the emulsion, DMFc  should be addressed to the authors.SupplementaryClick here for additional data file.


In this paper, we present a WiFi-based intrusion detection system called Wi-Alarm. Motivated by our observations and analysis that raw channel state information (CSI) of WiFi is sensitive enough to monitor human motion, Wi-Alarm omits data preprocessing. The mean and variance of the amplitudes of raw CSI data are used for feature extraction. Then, a support vector machine (SVM) algorithm is applied to determine detection results. We prototype Wi-Alarm on commercial WiFi devices and evaluate it in a typical indoor scenario. Results show that Wi-Alarm reduces much computational expense without losing accuracy and robustness. Moreover, different influence factors are also discussed in this paper. Intrusion detection is a dynamic process of monitoring whether there exists any entity breaking into a given area, then making alarms if necessary. It gains more and more attention and has great potential in many applications, such as border protection , smart hMost WiFi-based DFP approaches take advantage of the transmission characteristics of opportunistic WiFi signal in wireless channels, such as a received signal strength indicator (RSSI)  and chanAmong existing CSI-based systems of intrusion detection, considerable effort has been devoted to data preprocessing. Some do preprocessing to gain useful phase information ,9, otherIn this paper, we propose a novel and real-time system to detect intrusion. We call it Wi-Alarm because WiFi signals work as an alarm to warn people of intrusion here. Firstly, CSI samples are collected with CSI Tool . Then, wWe focus on the real-time performance of the whole system, which is neglected in previous research. In order to save computational expense significantly, we omit data preprocessing and extract features from raw CSI directly for intrusion detection, based on our analysis of the data preprocessing part in other systems and experimental verification. Given that real-time performance is critical, any effort to reduce computational expense is worthwhile if high detection accuracy can be maintained.We propose a simple but robust feature couple for intrusion detection where low latency is necessary. The feature couple could be promising for commercial use.Dynamic walking speeds are considered in our training phase. This improves Wi-Alarm’s sensitivity to human motion and enhances detection accuracy even when an intruder walks quite slowly.Different influence factors including MIMO, LOS/NLOS, size of sliding window and walking speed are discussed to guide better implementation of our system to improve the detection accuracy and robustness.Our main contributions are summarized as follows:The rest of this paper is organized as follows. In this section, we review the most related works on WiFi-based DFP detection.Kosba et al. proposed a system named RASID , in RASIGenerally, RSSI-based systems need to deploy more WiFi sensing nodes to reduce the influence of multipath effect for higher accuracy.CSI-based systems can be divided into two categories: using the amplitude of CSI and using both amplitude and phase of CSI. In the first class, robust passive motion detection (R-PMD)  passes tIn the second class, Kun et al. firstly employed a liner transformation to eliminate the significant random noise in CSI phase in passive detection of moving humans with dynamic speed (PADS) , it usesThe fine-grained information, CSI, not only makes it possible to sense human body, but also could recognize more subtle activity. WiFall  proposedDespite that many works have investigated CSI for device-free detection, the computational expense of the whole system is lack of study, and usually they just consider few influence factors. In this paper, we propose a low cost system for intrusion detection without losing accuracy. Moreover, different factors including MIMO, LOS/NLOS, size of sliding window and dynamic walking speeds are considered in this paper.In this section, we briefly introduce the architecture and flowchart of our system.As shown in Our system works as In this section, we give the details of Wi-Alarm system. Generally, we aim to propose a low-latency intrusion detection system with high accuracy. Therefore, the main indicators of the whole system are the performances of real-time and accuracy. In order to improve the real-time performance, we devote much effort to reduce the computational cost of each step without reducing detection accuracy.CSI is a channel attribution of communication link which describes attenuator factor on each transmission path including scattering, environmental weakness, distance attenuation, etc. Different from RSSI, which demonstrates superimposition of signals, CSI could be considered as the channel response depicting the amplitudes and phases of 30 subcarriers, so CSI is finer-grained and more stable.X and Y are the transmit and receive vector respectively while N is the ambient noise vector, then H is the CSI required. The estimated H could be expressed as:As shown in i-th subcarrier. In 802.11n protocol, it can range from 2.4 GHz to 2.4835 GHz. For each OFDM subcarrier, CSI is defined as:For each sample, the CSI can be expressed as: M transmit antennas and N receive antennas (NIC 5300 had three antennas), then there were n-th link could be expressed as a i-th package in n-th link.Since the CSI collection system is a MIMO system, suppose there are W, then W. Moreover, the time of data collection depended on the length of W. In this part, the length of sliding window was significant. If the size was too small, the CSI samples were too few to calculate an effective feature, which will reduce the detection accuracy. Otherwise, larger size means more time to collect more CSI samples, that will undermine the real-time performance of the system. In our system, through experiment analysis, it was appropriate to set to transmit 100 packages per second, i.e., CSI sampling frequency is 100 Hz. Therefore, the time needed for single CSI collection can be denoted as:Usually, we will not receive CSI packages endlessly, given a specific sliding window with length In Wi-Alarm, we extracted features from raw CSI data without preprocessing in order to save computational cost for better real-time performance. There was no doubt that omitting preprocessing will reduce much computational cost, in this part, we discuss the feasibility of preprocessing omission.In previous works, preprocessing was important to minimize environmental noise and usually done between raw CSI collection and feature extraction. This motivated us to think: how to understand the dynamic fluctuation, which is considered as noise before? With human motion, CSI values fluctuate during transmission. More dynamic fluctuation would make our detection easier. However, preprocessing in previous systems would suppress signal fluctuation which usually carries an intruder’s motion information.In order to validate the feasibility of preprocessing omission, we repeated the data preprocessing in R-PMD , a well-m-th package was averaged by previous Secondly, 1D linear interpolation algorithm is applied to fill the spaced samples. Lastly, environment noise was reduced by weighted moving average (WMA), CSI of the Then subsequent features were extracted from CSI values with or without preprocessing behaved quite differently. In conclusion, preprocessing omission is feasible. We decided to omit this step and extract features from raw CSI.Feature extraction plays an important role in intrusion detection. The features we choose should meet the following requirements.The features should be sensitive to human presence. The features extracted from the CSI of static environment should be quite different from the ones extracted from the CSI with human motion.The features should be easy to calculate. For real-time consideration, less computation cost on feature extraction would be better.In our system, only CSI amplitude was applied. Compared with raw CSI amplitude, raw CSI phase behaved with much randomness due to environment noise and an unsynchronized time clock between transmitter and receiver. We propose a simple but robust feature couple for Wi-Alarm in consideration of low latency. Various features have been applied in former research for detection, such as mean, variance, and distribution distance. However, the computational expense of distribution distance is much higher, which makes it inappropriate for real-time processing. Motivated by our experiment observations that, compared with static environment, human motion leads to higher CSI amplitudes with greater variances, we proposed the mean and variance of CSI amplitude to be a couple of good indicators for intrusion detection. Denote the feature couple as F is derived from one CSI sequence, given a specific sliding window W. Specifically, we calculated the mean/variance of all packages for one subcarrier firstly, then got the mean of all 30 subcarriers as the final In a fixed WiFi link, one feature couple F of one CSI sequence was calculated, it could be exploited in later SVM classifier generation and real-time intrusion detection.Then one feature couple With features we extracted, we needed to conduct an appropriate classifier on preliminary measurements collected from several cases. There were mainly two categories of methods that can be adopted for calibration-free detection: threshold-based and cluster-based. The former distinguish different states based on the threshold value which is gained from pre-collected data. The latter classifies different clusters as different states by comparing the centre distance of each cluster. Although environment calibration and threshold training were avoided in the cluster-based method, it assumed that in each group of measurements, there were at least two states involved. Otherwise, it would lead to one cluster or several clusters corresponding to a same state, which means miss or false detection. Consequently, the threshold based scheme was adopted in Wi-Alarm.Support vector machine (SVM), as a low cost threshold based classification, is one of the most popular machine learning techniques. A considerable number of CSI-based detection systems ,16,17,18C which controls overfitting of the model, and In this paper, we adopt the radial basis function (RBF) kernel (a.k.a. Gaussian kernel) as the kernel function so that a non-linear regression model can be constructed. This SVM has two such training factors: The training phase in our system was different from former works. Previous works only contain static fingerprint construction. In Wi-Alarm, shown in In this section, the experiment setup and evaluation of Wi-Alarm are illustrated.To evaluate the performance of Wi-Alarm, we conducted experiments on commercial devices. The configuration of our system is shown in As we mentioned that the train phase contained four cases, for each case, we conducted three measurements and each lasted for 2 min. In dynamic cases, the person can walk freely and easily without rules or restrictions. The detection results would be divided into two categories: with/without intrusion as shown in Since the influence of LOS/NLOS conditions were considered, the AP and DP were placed at two heights: 0.8 m and 2 m. In the condition of 0.8 m, the movement of a human would block LOS while not in the condition of 2 m.True negative (TN) rate: the probability that the human motion is correctly detected.True positive (TP) rate: the probability that the static environment is correctly classified.False negative (FN) rate: the probability that the human motion is incorrectly detected.False positive (FP) rate: the probability that the static environment is incorrectly classified.We use following four metrics to evaluate the performance of proposed Wi-Alarm system:We calculated TN/TP/FN/FP rates of all conditions and the discussion of our experiment results are shown as follows:Impact of preprocessing omission: among all the experiments with LOS and the size of sliding window s. R-PMD  was repeImpact of sliding window size: generally, choosing the size of the sliding window is critical. If the size is too small, the CSI samples are too few to calculate an effective feature. Otherwise, larger size means more time to collect more CSI samples, undermining the real-time performance of the system. According to our experiments, in Impact of different antennas: we considered four cases here: each individual antenna and the combination of all three antennas. The way of combination is taking the mean of all three antennas. Impact of LOS/NLOS: we changed the height of AP and DP to create two different detection environments: LOS and NLOS, the former one means that LOS would be blocked by human motion during the monitoring phase by low placement of AP and DP, while the latter one would not by relatively high placement. C, as C controls overfitting of the model, so it should not be too big and 0.8 was a good setting. On the other hand, as Impact of SVM parameters: the selection of SVM parameters also had a significant impact on the detection rate of Wi-Alarm. Through our experiment evaluations, on one hand, higher detection rates were achieved with bigger In this paper, we present a passive intrusion detection system called Wi-Alarm, which is based on CSI using WiFi. In our system, attacks are performed when an intruder is entering the monitoring area unexpectedly wherever he comes from. Wi-Alarm is proposed mainly to distinguish two states (human presence and absence) and detect whether there exist any people in the area of interest. It could be applied in the field of safety monitoring.Motivated by our observation that raw CSI of WiFi is sensitive enough to detect human motion, we omit data preprocessing and utilize raw CSI amplitude for feature extraction, SVM algorithm is used as a classifier in our system. We have conducted extensive experiments, evaluate results to validate the robustness, high detection rate and real-time of Wi-Alarm. Besides, different influence factors are considered in our experiments which will guide better implemention of Wi-Alarm.However, there still exists some limitations. Firstly, when installed in a different scenario, our system needs to be trained again to find a suitable threshold. Moreover, usually there already exists someone in the given area which means the original environment is not static before any intrusion occurs. Consequently, we should explore new features to model the motion introduced by the intruder coming from the outside aiming to distinguish it from the motion inside.Future work will focus on exploring novel and effective features to enhance the adaptability of our system and the functions of detecting more types of attacks.