25318357
Towards Fuzzy Compositional Modelling
Compositional modelling (CM) has been applied to synthesize automatically plausible scenarios in many problem domains with promising results. However, it is assumed that the generic and reusable model fragments within the knowledge base can all be expressed by precise and crisp information. This paper presents an initial attempt to extend the existing CM work to allow the generation of scenario spaces which are capable of representing, storing and supporting inference about imprecise or ill-defined data, by the use of fuzzy sets. A knowledge representation formalism for both fuzzy parameters and fuzzy constraints is incorporated into the representation of conventional model fragments. The applicability of the proposed method is illustrated by means of a simple worked example for supporting crime investigation.
2587320
Dynamic Flexible Constraint Satisfaction
Existing techniques for solving constraint satisfaction problems (CSPs) are largely concerned with a static set of imperative, inflexible constraints. Recently, work has addressed these shortcomings of classical constraint satisfaction in the form of two separate extensions known as flexible and dynamic CSP. Little, however, has been done to combine these two approaches in order to bring to bear the benefits of both in solving more complex problems. This paper presents a new integrated algorithm, Flexible Local Changes, for dynamic flexible problems. It is further shown how the use of flexible consistency-enforcing techniques can improve solution re-use and hence the efficiency of the core algorithm. Empirical evidence is provided to support the success of the present approach.
17008570
A rough-fuzzy approach for generating classification rules
The generation of effective feature pattern-based classification rules is essential to the development of any intelligent classifier which is readily comprehensible to the user. This paper presents an approach that integrates a potentially powerful fuzzy rule induction algorithm with a rough set-assisted feature reduction method. The integrated rule generation mechanism maintains the underlying semantics of the feature set. Through the proposed integration, the original rule induction algorithm (or any other similar technique that generates descriptive fuzzy rules), which is sensitive to the dimensionality of the dataset, becomes usable on classifying patterns composed of a moderately large number of features. The resulting learned ruleset becomes manageable and may outperform rules learned using more features. This, as demonstrated with successful realistic applications, makes the present approach effective in handling real world problems.
16338653
Fuzzy-rough data reduction with ant colony optimization
Feature selection refers to the problem of selecting those input features that are most predictive of a given outcome; a problem encountered in many areas such as machine learning, pattern recognition and signal processing. In particular, solution to this has found successful application in tasks that involve datasets containing huge numbers of features (in the order of tens of thousands), which would be impossible to process further. Recent examples include text processing and web content classification. Rough set theory has been used as such a dataset pre-processor with much success, but current methods are inadequate at finding minimal reductions, the smallest sets of features possible. To alleviate this difficulty, a feature selection technique that employs a hybrid variant of rough sets, fuzzy-rough sets, has been developed recently and has been shown to be effective. However, this method is still not able to find the optimal subsets regularly. This paper proposes a new feature selection mechanism based on ant colony optimization in an attempt to combat this. The method is then applied to the problem of finding optimal feature subsets in the fuzzy-rough data reduction process. The present work is applied to complex systems monitoring and experimentally compared with the original fuzzy-rough method, an entropy-based feature selector, and a transformation-based reduction method, PCA. Comparisons with the use of a support vector classifier are also included.
14492081
Linguistic Bayesian Networks for reasoning with subjective probabilities in forensic statistics
Recent work in forensic statistics has shown how Bayesian Networks (BNs) can be used to infer the probability of defence and prosecution statements based on forensic evidence. This is an important development as it helps to quantify the meaning of forensic expert testimony during court proceedings, for example, that there is "strong support" for the defence or prosecution position. Due to the lack of experimental data, inferred probabilities often rely on subjective probabilities provided by experts. Because these are based on informed guesses, it is very difficult to express them accurately with precise numbers. Yet, conventional BNs can only employ probabilities expressed as real numbers. To address this issue, this paper presents a novel extension of probability theory. This allow the expression of subjective probabilities as fuzzy numbers, which more faithfully reflect expert opinion. By means of practical a example, it will be shown that the accurate representation of this lack of precision in reasoning with subjective probabilities has important implications for the overall result.
37663323
Prioritising Behaviours in Qualitative Simulation
4966601
Power controlled network protocols for Multi-Rate ad hoc networks
In this paper, we propose for multi-rate ad hoc networks a cross-layer design using power control, called MRPC. MRPC consists of two parts. First, we propose a multi-rate power controlled MAC protocol, called MRPC-MAC. By carefully controlling the transmission power, it can enable concurrent transmissions, which is otherwise impossible for the IEEE 802.11 standard. Second, we propose a multi-rate power controlled routing protocol, called MRPC-Routing. Different from traditional routing protocols, MRPC-Routing is not intended to find end-to-end paths, rather, it determines the next hop right before transmitting packets at the MAC layer. In this protocol, it uses the effective transport capacity as the routing metric such that short links with high bandwidth are preferred and more concurrent transmissions can be enabled. Having these coupled power controlled MAC protocol and routing protocol, MRPC can greatly improve the spatial reuse and the network throughput. Simulation results also show MRPC-MAC, MRPC-routing, and especially MRPC, can improve the network throughput significantly.
7724198
Admission Control for Providing QoS in Wireless Mesh Networks
An admission control algorithm should be properly designed to guarantee the quality of service (QoS) in wireless mesh networks (WMNs). Based on channel business ratio, an admission control algorithm (ACA) is proposed to provide QoS for realtime and non-realtime traffic. For realtime traffic, all the nodes on a route make the admission control decision based on the estimation of available bandwidth. For non-realtime traffic, a rate adaption algorithm is proposed to adjust the sending rates of the source nodes to prevent a network from entering a saturated status. Finally, we demonstrate the effectiveness by simulations in NS-2.
15138853
A Cluster Warhead Projection-Time Self-Adaptive Algorithm and Simulation
This paper proposes a self-adaptive algorithm for the projection-time of the cluster warhead, which is applicable to the realization of the engineering project with low cost. On the basis of keeping the simplified correction strategy that keeps the constant distance of the projection points and through detecting the deviation of the actual trajectory data at a specific time with respect to the pre-determined trajectory data, this algorithm adopts the simple functional relationship to calculate the correction of the projection time. It adopts Monte Carlo computer simulation method to verify. The circular probable error of the projection point, caused by this algorithm, at the horizontal distance is 8.2 meters. The working content and the flow procedures for the setter and the fuze projection-time self-adaptive controller, which adopts this algorithm, are finally concluded. While being free from influencing the precision, this algorithm can effectively simplify the design of the projection-time self-adaptive projection controller, can reduce the volume and the circuit power consumption, and is applicable to be used on the fuze.
45281264
Optimum Power Assignment for Maximum Throughput in CDMA Personal Communication Systems with Integrated Voice/Data Traffic
A CDMA personal communication system with integrated voice/data traffic is considered, in which the link error performance is controlled according to the voice error rate requirement, and the acceptable data traffic error rate is ensured by ARQ. Optimum power assignment (or allocation) between voice and data users is investigated to maximize the total system throughput. A graphical method (the tangent method) is described to obtain this optimum power allocation. The maximum throughput is expressed as a function of other system parameters. The tangent method is further used to measure the impact of transmission quality on the maximum data throughput. Numerical results and a design example are given for a power controlled wideband IS-95 type wireless personal communication system.
15141835
Design of Range Correction Fuze Trajectory Calculation and Control Device
For a range correction fuze of a rocket range-extended projectile, a DSP-based trajectory calculation and correction controller that is cooperated with MCU is designed to examine the axial acceleration during the flying of a projectile, and to perform the trajectory calculation and the start-up time calculation of a correction mechanism, and to control the action of a resistance-correction mechanism. When designing the hardware and the software, the tasks for DSP and MCU are reasonably assigned. The DSP mainly completes the collection of the acceleration data, the trajectory calculation and the start-up time calculation of the resistance-correction mechanism, while MCU mainly completes the time counting and controls the startup of the resistance-correction mechanism according to the time calculated by DSP. This device also can store the flying acceleration measurement data of the projectile, the trajectory calculation results, etc., which can be adopted as the basic data for analyzing the working correctness of the range correction fuse at the research stage. It is proved in the range test that this device can resist the high-impact overloading during the emission, and can normally complete the tasks such as the trajectory calculation and the resistance-correction mechanism startup control during the flying of the projectile.