11082409
Answering relationship queries on the web
Finding relationships between entities on the Web, e.g., the connections between different places or the commonalities of people, is a novel and challenging problem. Existing Web search engines excel in keyword matching and document ranking, but they cannot well handle many relationship queries. This paper proposes a new method for answering relationship queries on two entities. Our method first respectively retrieves the top Web pages for either entity from a Web search engine. It then matches these Web pages and generates an ordered list of Web page pairs. Each Web page pair consists of one Web page for either entity. The top ranked Web page pairs are likely to contain the relationships between the two entities. One main challenge in the ranking process is to effectively filter out the large amount of noise in the Web pages without losing much useful information. To achieve this, our method assigns appropriate weights to terms in Web pages and intelligently identifies the potential connecting terms that capture the relationships between the two entities. Only those top potential connecting terms with large weights are used to rank Web page pairs. Finally, the top ranked Web page pairs are presented to the searcher. For each such pair, the query terms and the top potential connecting terms are properly highlighted so that the relationships between the two entities can be easily identified. We implemented a prototype on top of the Google search engine and evaluated it under a wide variety of query scenarios. The experimental results show that our method is effective at finding important relationships with low overhead.
6802163
Transaction reordering with application to synchronized scans
Traditional workload management methods mainly focus on the current system status while information about the interaction between queued and running transactions is largely ignored. An exception to this is the transaction reordering method, which reorders the transaction sequence submitted to the RDBMS and improves the transaction throughput by considering both the current system status and information about the interaction between queued and running transactions. The existing transaction reordering method only considers the reordering opportunities provided by analyzing the lock conflict information among multiple transactions. This significantly limits the applicability of the transaction reordering method. In this paper, we extend the existing transaction reordering method into a general transaction reordering framework that can incorporate various factors as the reordering criteria. We show that by analyzing the resource utilization information of transactions, the transaction reordering method can also improve the system throughput by increasing the resource sharing opportunities among multiple transactions. We provide a concrete example on synchronized scans and demonstrate the advantages of our method through experiments with a commercial parallel RDBMS.
379901
Answering linear optimization queries with an approximate stream index
We propose a SAO index to approximately answer arbitrary linear optimization queries in a sliding window of a data stream. It uses limited memory to maintain the most “important” tuples. At any time, for any linear optimization query, we can retrieve the approximate top-K tuples in the sliding window almost instantly. The larger the amount of available memory, the better the quality of the answers is. More importantly, for a given amount of memory, the quality of the answers can be further improved by dynamically allocating a larger portion of the memory to the outer layers of the SAO index.
235091
Efficient detection of empty-result queries
Frequently encountered in query processing, empty query results usually do not provide users with much useful information. Yet, users might still have to wait for a long time before they disappointingly realize that their results are empty. To significantly reduce such unfavorable delays, in this paper, we propose a novel method to quickly detect, without actual execution, those queries that will return empty results. Our key idea is to remember and reuse the results from previously-executed, empty-result queries. These results are stored in the form of so-called atomic query parts so that the (partial) results from multiple queries can be combined together to handle a new query without incurring much overhead. To increase our chance of detecting empty-result queries with only a limited storage, our method (1) stores the most "valuable" information about empty-result queries, (2) removes redundant information among different empty-result queries, (3) continuously updates the stored information to adapt to the current query pattern, and (4) utilizes a set of special properties of empty results. We evaluate the efficiency of our method through a theoretical analysis and an initial implementation in PostgreSQL. The results show that our method has low overhead and can often successfully avoid executing empty-result queries.
10289907
Partial Materialized Views
Early access to partial query results is highly desirable during exploration of massive data sets. However, it is challenging to provide transactionally consistent, immediate partial results without significantly increasing queries' execution time. To address this problem, this paper proposes a partial materialized view (PMV) method to cache some of the most frequently accessed results rather than all the possible results. Compared to traditional materialized views, the proposed PMVs do not require maintenance during insertion into base relations, and have much smaller storage and maintenance overhead. Upon the arrival of a query, the RDBMS first searches the PMV and returns to the user the cached partial results. Since a large portion of the PMV is cached in memory, this usually finishes within a millisecond. Then the RDBMS continues to execute the query to find the remaining results. The efficiency of our PMV method is evaluated through a simulation study, a theoretical analysis, and an initial implementation in PostgreSQL.
14324910
Challenging issues in iterative intelligent medical search
Searching for medical information on the Web is highly popular these days. To facilitate ordinary people to perform medical search and preliminary disease self-diagnosis, we have built an intelligent medical Web search engine called iMed. iMed introduces and extends pattern recognition and expert system technology into the search engine domain. It uses medical knowledge and an interactive questionnaire to help searchers form queries. Due to searcherspsila limited medical knowledge and the taskpsilas inherent difficulty, searchers often cannot find desired search results in a single pass and have to search iteratively for multiple passes. For this purpose, iMed provides an iterative search advisor that guides searchers to refine their inputs. Based on our experience in building and using iMed, this paper summarizes the common difficulties faced by ordinary medical information searchers and the research issues that deserve attention from people working in the pattern recognition and medical search areas.
1980102
Dynamic Rate Assignment and Power Control in Uplink UMTSW-CDMA Systems
Power control and rate assignment are important tools to maximize system resource utilization while satisfying quality of service (QoS) in a code division multiple access (CDMA) system. In this paper, we propose an algorithm of simultaneously adapting transmission power and data rate to maximize system throughput and minimize the power consumption in a wideband CDMA (W-CDMA) network. The greedy rate packing (GRP) allocation scheme, where high date rates are assigned to users with favorite channel conditions and lower interference, is employed for the rate adaptation. Compared with the results using Zhao et al. (2005) (algorithm 2), close-loop power control (CLPC) alone, and rate adaptation alone approaches, our proposed power and rate transmission scheme (algorithm 1) significantly improves transmission efficiency
18530879
Detection of Hidden Information in Webpages Based on Randomness
An effective detection algorithm based on the randomness is devised in this paper for stego-webpages with different steganographies. The parts where secret information embedded in a webpage can generally be represented as two states, which can be described in binary code string. The randomness of the states varies a great deal depending on the webpage part carrying secret information or not. This paper presents a procedure to transform the binary code string into octal string to capture the randomness, from which some statistical features have been discovered. The theoretical description and proof are given that these features can be employed as a criterion to test whether a webpage contains secret information or not. Experiments show that this algorithm can effectively detect the stego-webpages based on letter changing in tags and invisible characters embedding.
18783200
A Novel Low-Power Clock Skew Compensation Circuit
The clock is a periodic synchronization signal used as a time reference for data transfers in synchronous digital systems. However, the clock skew constrains the improvement of clock frequencies and affects the reliability of systems. One skew reduction technique is the use of clock deskew circuits. They can be classified into two methods: delay-locked loop (DLL) deskewing and synchronous mirror delay (SMD) deskewing. The DLL deskewing achieves a fine accuracy, but suffers from slow locking. Reversely, the adjustment of the SMD deskewing is fast, but suffers from a poor accuracy. In this paper, a low-power full-digital hybrid clock deskew circuit is presented. It uses a SMD as coarse delay line and a digital-DLL as a fine delay line. The SPICE simulation shows that the proposed clock deskew circuit achieves fine accuracy , fast locking, and low power.
13494891
Tracking Telescope Aiming Point for Bioptic Driving Surveillance
Bioptic telescope is a visual aid used by some people with impaired vision for driving and to qualify for licensing. Data on how and when bioptic drivers use the telescope and what they look at with it are important in biop- tic driving studies. A video-based technique to track bioptic drivers' spectacle frames, which represent telescope aiming point, is presented in this paper. With three retro-reflective markers pasted on the bioptic spectacles frame, aiming point is determined from the angles formed by the three markers. Telescope aiming points projected on a scene camera image is calculated by means of interpolation based on a novel calibration method in which a laser pointer is mounted on the spectacle frame. A large number of calibration points are sampled automatically when the driver scans across the scene. Preliminary experiment demonstrated that the average error over a 65° ×48° field was only 0.89 degree.
30097914
Improved Method for Network Danger Evaluation Based on Immunology Principle
This paper proposes an improved immunological surveillance for network danger evaluation model, focusing on intrusion detection and countermeasures with respect to widely-used networks. An improved intrusion detection mechanism based on self-tolerance, clone selection, and immune surveillance is established. A new network security evaluation method using antibody concentration to quantitatively analyze the degree of intrusion danger level is presented. Additionally, this new hierarchical management framework of the proposed model adopt to improve the detection efficiency and to overcome the shortcoming of the local optimum. The experimental results show that the proposed model is a good solution for network security evaluation.