Abstract

Abstract
As the vision of Service Oriented Computing matures the need for well defined architectures and protocols is essential. The SOC paradigm has several requirements to work properly: service composition and cooperation in a loosely coupled fashion, ability to adapt autonomously to environmental and business changes, proper integration between services, modularity and service dynamics. The OSGi[13] platform embodies key aspects of the SOC paradigm by defining a modular and dynamic architecture. However there is still room for improvement, namely on the creation of architectures and mechanisms to improve the dependability of the platform by strengthening key properties such as availability, reliability, integrity, safety and maintainability. In this paper we propose a OSGi based middleware layer that offers the strong modular and dynamic properties required in a SOC environment, while addressing dependability concerns. The starting point to achieve this is by instrumenting a OSGi implementation with means to monitor and manage it accordingly to business and environmental requirements. By relying on group communication facilities and some properties from the OSGi specification we are able to migrate OSGi environments among nodes, thus minimizing service outage in the presence of faults and addressing, at the same time, Service Level Agreement properties by migrating (or shutting down) services that are consuming more resources than agreed/expected. © 2008 ACM.

Abstract
In this paper we describe a regular expression pattern matching approach for reconfigurable hardware. Following a Non-deterministic Finite Automata direction, we introduce three new basic building blocks to support constraint repetitions syntaxes more efficiently than previous works. In addition, a number of optimization techniques are employed to reduce the area cost of the designs and maximize performance. Our design methodology is supported by a tool that automatically generates the circuitry for the given regular expressions and outputs Hardware Description Language representations ready for logic synthesis. The proposed approach is evaluated on network Intrusion Detection Systems (IDS). Recent IDS use regular expressions to represent hazardous packet payload contents. They require high-speed packet processing providing a challenging case study for pattern matching using regular expressions. We use a number of IDS rulesets to show that our approach scales well as the number of regular expressions increases, and present a step-by-step optimization to survey the benefits of our techniques. The synthesis tool described in this study is used to generate hardware engines to match 300 to 1,500 IDS regular expressions using only 10-45 K logic cells and achieving throughput of 1.6-2.2 and 2.4-3.2 Gbps on Virtex2 and Virtex4 devices, respectively. Concerning the throughput per area required per matching non-Meta character, our hardware engines are 10-20 x more efficient than previous Field Programmable Gate Array approaches. Furthermore, the generated designs have comparable area requirements to current application-specific integrated circuit solutions.

Abstract

Abstract
A long-period-grating-based fiber optic Michelson modal interferometer with coherence addressing and heterodyne interrogation is studied as a sensing structure for measuring environmental refractive index, temperature, and liquid level. The effects of several system parameters on the measurements are investigated. Experimental results show that the sensitivity to the external refractive index increases with the order of cladding mode and with a reduction of the fiber diameter. The decrease of the fiber diameter from 125 mu m down to 70 mu m enhances the sensitivity to the external index by a factor of 2.7. It is also shown that the use of a silica-core fiber increases the sensitivity to the external index by a factor of 1.4 and reduces the thermal sensitivity by a factor of 2.5 compared to a standard fiber. (C) 2008 Society of Photo-Optical Instrumentation Engineers.

Abstract