1105765
Service discovery and measurement based on DAML-QoS ontology
As more and more Web services are deployed, Web service's discovery mechanisms become essential. Similar services can have quite different QoS behaviors. For service selection and management purpose, it is necessary to clearly specify QoS constraints and metrics definitions for Web services. We investigate on the semantic QoS specification and introduce our design principles on it. Based on the specification refinement and conformance, we introduce the QoS matchmaking algorithm with multiple matching degrees. The matchmaking prototype is designed to prove the feasibility. Well-defined Metrics can be further utilized by measurement organizations to monitor and evaluate the promised service level objectives.
1982773
QoS measurement issues with DAML-QoS ontology
With the industry's efforts in promoting the use of Web services, a huge number of Web services are being developed for the Web. To improve the service provider's competition advantage, it is necessary to support QoS-aware service discovery mechanism as well as the corresponding measurement system. In this paper we present a QoS measurement framework based on the DAML-QoS ontology, together with the measurement code generator. The DAML-QoS ontology is designed to specify QoS constraints for Web services. It works as a complement to DAML-S to provide QoS-aware service discovery. This paper focuses on its measurement framework to check the service provider's runtime compliance with the advertised service level. The code generator helps to generate the measurement code according to the DAML-QoS specification. This ontology level specification tries to reduce the service's integration complexity and achieve better interoperability, automation and extensibility
971957
DAML-QoS ontology for Web services
As more and more Web services are deployed, Web service's discovery mechanisms become essential. Similar services can have quite different QoS levels. For service selection and management purpose, it is necessary to explicitly, precisely, and unambiguously specify various constraints and QoS metrics for Web services descriptions. This paper provides a novel DAML-QoS ontology as a complement for DAML-S ontology to provide a better QoS metrics model. Three layers are defined together with clear role descriptions for developments. Cardinality constraints are utilized to describe the QoS property constraints. Basic profile is presented for general Web service's description and the speed startup of ontology definition. Matchmaking algorithm for QoS property constraints is presented and different matching degrees are described. When incorporated with DAML-S, multiple service levels can be described through attaching multiple QoS profiles to one service profile. Well-defined Metrics can be further utilized by measurement organizations to guarantee the promised service level.
16619155
QoS-Aware and Federated Enhancement for UDDI
With more and more Web services appearing on the Web, Web serviceâ€™s discovery mechanisms become essential. UDDI is an online registry standard to facilitate the discovery of business partners and services. Service requesters can choose good performance Web services by manual test and comparison. However, this method of choosing is inefficient and costly in terms of time and money. The ability to predict the quality of service is missing in UDDI. Furthermore, UDDI registries in federated organizations should be able to share more about the service requesterâ€™s connection information to make better predictions for servicesâ€™ performances. To address these problems, we propose UX (UDDI eXtension), a system that facilitates requesters to discover services with good performance. In each enterprise domain, the requestersâ€™ QoS feedback is received and then stored in a local UX server. By sharing these experiences from all the requesters in the local domain, the system can predict the serviceâ€™s future performance. To support the discovery between different cooperation domains, we design a general federated service and then enhance the UX systemâ€™s federated discovery ability based on this federated service. The system handles the federated inquiry and provides a simple view over the whole federation. Meanwhile the UX serverâ€™s inquiry interface will still conform to the UDDI Specification.
14695460
Evaluation of a Decentralized Architecture for Large Scale Collaborative Intrusion Detection
An important problem in network intrusion detection is how to detect large scale coordinated attacks such as scans, worms and denial-of-service attacks. These coordinated attacks can be difficult to detect at an early stage, since the evidence of the attack may be widely distributed across different subnetworks in the Internet. A critical issue for research is how to detect these large scale attacks by correlating information from multiple intrusion detection systems in an efficient manner. Several collaborative detection systems have been proposed in the literature. However, these proposals have lacked large scale testing in real networks, and the practicalities of how to optimize the trade-off between detection accuracy and reaction time of these systems has not been demonstrated. To address these challenges, we propose LarSID, a scalable decentralized large scale intrusion detection framework. LarSID provides a service for defending against attacks by sharing potential evidence of intrusions between participant intrusion detection systems via a distributed hash table (DHT) architecture. In particular, we investigate how to optimize the trade-off between detection accuracy and reaction time of LarSID based on an analysis of a large, real-world intrusion detection dataset (DShield Dataset), which has been collected from over 1600 firewall administrators across the world. LarSID has been deployed and tested on the PlanetLab testbed, and is built on top of OpenDHT - a public DHT service. Our experimental results show significant reductions in detection latency compared to a centralized detection architecture. Currently, LarSID has been deployed on 128 PlanetLab nodes as a large scale intrusion detection service.
9275481
RoboCup 2004 Competitions and Symposium: A Small Kick for Robots, a Giant Score for Science
RoboCup is an international initiative with the main goals of fostering research and education in artificial intelligence and robotics, as well as of promoting science and technology to world citizens. The idea behind RoboCup is to provide a standard problem for which a wide range of technologies can be integrated and examined, as well as being used for project-oriented education, and to organize annual events open to the general public, at which different solutions to the problem are compared. The eighth annual RoboCup -- RoboCup 2004 -- was held in Lisbon, Portugal, from 27 June to 5 July. In this article, a general description of RoboCup 2004 is presented, including summaries concerning teams, participants, distribution into leagues, main research advances, as well as detailed descriptions for each league.
17258053
Hybrid fuzzy control of the inverted pendulum via vertical forces
In this article, we look at the excellent effect of vertical force as regards the stabilization of the inverted pendulum (IP) and demonstrate how the fuzzy control design methodology can be used to construct a hybrid fuzzy control system that incorporates PD control into a Takagi–Sugeno fuzzy control structure for stabilizing the IP via a vertical force. By gaining an intuitive understanding of the dynamics of the IP, the IP state space is fuzzily divided into six regions. In each region, a PD controller is designed to satisfy the stability conditions obtained by Lyapunov’s direct and indirect methods. It shows that the proposed hybrid fuzzy control scheme provides a more flexible and intuitive way to stabilize the IP via a vertical force. © 2005 Wiley Periodicals, Inc.
1882154
Providing Quality of Service in IEEE 802.11 WLAN
This paper aims to provide quality of service (QoS) for IEEE 802.11 wireless local area network (WLAN). Specifically, we develop a new scheduling algorithm in link layer to support multimedia services with guaranteed QoS in WLAN. The proposed scheduling algorithm makes use of the idle system time to reduce average packet loss of real-time (RT) variable-bit-rate (VBR) services, while satisfying required transmission delay and bandwidth requirements of all RT services. Detailed analysis is given by taking into account several key statistical factors, such as service traffic model, the ratio between the polling period and the contention period (CP), burst generation probabilities. Performance is evaluated through OPNET simulation. Simulation results demonstrate that our proposed joint scheme is effective in terms of both system resource utilization and QoS provisioning
9173348
Particle Swarm Optimization for Simultaneous Optimization of Design and Machining Tolerances
Tolerance assignment is an important issue in product design and manufacturing. However, this problem is commonly formulated as nonlinear, multi-variable and high constrained model. Most of the heuristics for this problem are based on penalty function strategy which unfortunately suffers from inherent drawbacks. To overcome these drawbacks, this paper presented a new powerful tool-Particle Swarm Optimization algorithm (PSO) and meanwhile proposed a sophisticated constraints handling scheme suitable for the optimization mechanism of PSO. An example involving simultaneously assigning both design and machining tolerances based on optimum total machining cost is employed to demonstrate the efficiency and effectiveness of the proposed approach. The experimental result based on the comparison between PSO and GA show that the new PSO model is a powerful tool.