Incorporating sensor nodes with data aggregation capability to transmit less data flow in wireless sensor networks could reduce the total energy consumption. This calls for the efficient and effective data-centric routing algorithm to facilitate this advantage. In the first part of this paper, we model the data-centric routing problem by rigorous mixed integer and linear mathematical formulation, where the objective function is to minimize the total transmission cost subject to multicast tree constraints. With the advancement of sensor network technology, sensor nodes with configurable transmission radius capability could further reduce energy consumption. The second part of this paper considers the transmission radius assignment of each sensor node and the data-centric routing assignment jointly. The objective function is to minimize the total power consumption together with consideration of construction of a data aggregation tree and sensor node transmission radius assignment. The solution approach is based on Lagrangean relaxation in conjunction with the novel optimization-based heuristics. From the computational experiments, it is shown that the proposed algorithms calculate better solution than other existing heuristics with improvement ratio up to 169% and 59% with respect to fixed transmission radius and configurable transmission radius for network with 300 random generated nodes.

In optical burst switching (OBS) networks, the contention of optical bursts is the most serious problem due to the lack of buffers within the networks. Various deflection routing schemes and a routing scheme based on pre-calculated multiple paths have been proposed to resolve the contention. The latter routing scheme can successfully maintain a relatively limited transfer delay of optical bursts. This paper proposes a new decentralized routing scheme based on multiple paths to effectively resolve the contention of optical bursts. In this scheme, each source node splits the traffic load into pre-calculated multiple paths adaptively according to the measured loss rate of the optical bursts transferred through each path. This scheme does not require frequent notification of the measured loss rate because each source node selects one of the multiple paths probabilistically. In the OBS networks, the average transfer delay in the multi-path routing always exceeds that in a single-path routing because alternative paths with a larger transfer delay are also utilized in the multi-path routing. Thus, this paper proposes an adaptive load splitting method in which load splitting ratios for the multiple paths are autonomously adjusted to minimize the average transfer delay based on the condition that the required loss rate of optical bursts is satisfied. The performance of the proposed scheme was evaluated by computer simulation and based on the evaluation results; the ability of the proposed scheme to adjust the load splitting ratios for the multiple paths autonomously and avoid the contention of optical bursts adaptively is clarified even if the traffic load applied to the OBS network changes.

A design of a linearly-polarized non-resonant waveguide broad-wall transverse slot linear array with suppressed grating lobes is presented. Each unit element in the array consists of a transverse slot, an inductive post and a parasitic dipole-pair at a height of half of the free space wavelength. It is designed as an isolated unit without considering mutual coupling by using the Method of Moments (MoM) for radiation suppression in grating beam direction and reflection cancellation at the input. The elements thus designed are used in a travelling wave array environment. It is predicted that the reflection is less than -20 dB at 11.95 GHz while the grating lobes are suppressed by more than 15 dB. The design and the characteristics of the array are confirmed by measurements.

The relative permittivity and permeability are discontinuous at the grating profile, and the electric and magnetic flux densities are continuous. As for the method of analysis for scattering waves by surface relief gratings placed in conical mounting, the spatial harmonic expansion approach of the flux densities are formulated in detail and the validity of the approach is shown numerically. The present method is effective for uniform regions such as air and substrate in addition to grating layer. The matrix formulations are introduced by using numerical calculations of the matrix eigenvalue problem in the grating region and analytical solutions separated for TE and TM waves in the uniform region are described. Some numerical examples for linearly and circularly polarized incidence show the usefulness of the flux densities expansion approach.

Mobile agent technology is applied to enhance the remote network management of large-scale networks, and real-world oriented entertainment systems, and so forth. In order to communicate, the agents exchange messages mutually and migrate repeatedly among terminals. Although these systems efficiently accomplish the tasks by using a large quantity of mobile agents, they have a serious problem in that the number of messages between agents increases in proportion to the square of the number of agents. These systems have to reduce the communication costs, such as the number of hosts relaying messages; however, the conventional message-delivering schemes alone cannot keep the communication costs to a minimum under all conditions. To minimize the communication costs, we propose a hybrid message-delivering scheme which dynamically selects the optimal message-delivering schemes. Firstly, we evaluate the communication costs of conventional schemes, and we design the hybrid message-delivering scheme. Then we perform simulation evaluations to derive the threshold value for switching a scheme to minimize the communication costs.

Current Web services testing techniques are unable to assure the desired level of trustworthiness, which presents a barrier to WS applications in mission and business critical environments. This paper presents a framework that assures the trustworthiness of Web services. New assurance techniques are developed within the framework, including specification verification via completeness and consistency checking, test case generation, and automated Web services testing. Traditional test case generation methods only generate positive test cases that verify the functionality of software. The proposed Swiss Cheese test case generation method is designed to generate both positive and negative test cases that also reveal the vulnerability of Web services. This integrated development process is implemented in a case study. The experimental evaluation demonstrates the effectiveness of this approach. It also reveals that the Swiss Cheese negative testing detects even more faults than positive testing and thus significantly reduces the vulnerability of Web services.

In this letter, a new channel-adaptive beamforming method is proposed for OFDMA systems with smart antennas. In the method, the size of a cluster for resource unit is determined adaptively according to a region-splitting criterion. It is shown by simulations that the proposed method shows good performance in both frequency-flat and frequency-selective channels.

In recent years, considerable attention has been devoted to continuously running software systems whose performance characteristics are smoothly degrading in time. Software aging often affects the performance of a software system and eventually causes it to fail. A novel approach to handle transient software failures due to software aging is called software rejuvenation, which can be regarded as a preventive and proactive solution that is particularly useful for counteracting the aging phenomenon. In this paper, we focus on a high assurance software system with fault-tolerance and preventive rejuvenation, and analyze the stochastic behavior of such a highly critical software system. More precisely, we consider a fault-tolerant software system with two-version redundant structure and random rejuvenation schedule, and evaluate quantitatively some dependability measures like the steady-state system availability and MTTF based on the familiar Markovian analysis. In numerical examples, we examine the dependence of two fault tolerant techniques; design and environment diversity techniques, on the system dependability measures.

Automated reasoning of inductive theorems is considered important in program verification. To verify inductive theorems automatically, several implicit induction methods like the inductionless induction and the rewriting induction methods have been proposed. In studying inductive theorems on higher-order rewritings, we found that the class of the theorems shown by known implicit induction methods does not coincide with that of inductive theorems, and the gap between them is a barrier in developing mechanized methods for disproving inductive theorems. This paper fills this gap by introducing the notion of primitive inductive theorems, and clarifying the relation between inductive theorems and primitive inductive theorems. Based on this relation, we achieve mechanized methods for proving and disproving inductive theorems.

Grid computing is an open, heterogeneous and highly dynamic environment based on the principles of service oriented computing. It focuses on basic infrastructure for coordinated resource sharing among virtual organizations to achieve high performance and availability. However, use of existing Grid computing environment is quite complex and requires a lot of human intervention. In order to avoid this intervention, enhancements are required in bringing autonomy and semantics in existing Grid infrastructure. Semantics would act as glue for autonomy in the process of efficient resource discovery and utilization. Several ontologies and ontology languages have been proposed in this regard which not only have some shortcoming but also poses a sort of overhead for the Grid environment. On the other hand, agents are autonomous problem solving entities, and can negotiate semantically for interoperation with each other in dynamic environments. Inspired from the concept of Autonomous Decentralized Systems, we propose that the above mentioned goals can be achieved by integrating FIPA Multi Agent Systems with the Grid Service Architecture and hence to lay the foundation for Autonomous Semantic Grid. Autonomous Semantic Grid system architecture is aimed to provide an improved infrastructure by bringing autonomy, semantic interoperability and decentralization in the Grid computing for emerging applications. This paper then presents implementation details of first milestone toward Autonomous Semantic Grid realization based on a middleware, namely AgentWeb Gateway for integration of Multi Agent Systems and Grid Service Architecture. Evaluation of the system has also been performed over a number of application scenarios.

There are three well-known approaches to using scan design to apply two-pattern testing: broadside testing (functional justification), skewed-load testing and enhanced scan testing. The broadside and skewed-load testing use the standard scan design, and thus the area overheads are not high. However fault coverage is low. The enhanced scan testing uses the enhanced scan design. The design uses extra latches, and allows scan-in any two-pattern testing. While this method achieves high fault coverage, it causes high area overhead because of extra latches. This paper presents a new scan design where two-pattern testing with high fault coverage can be performed with area overhead as low as the standard scan design. The proposed scan-FFs are based on master-slave FFs. The input of each scan-FF is connected to the output of the master latch and not the slave latch of the previous FF. Every scan-FF maintains the output value during scan-shift operations.

White-light emitting diode lamps for general illumination can be realized by a combination of a blue light-emitting diode semiconductor die and phosphors. Newly developed oxynitride and nitride phosphors are promising candidates for this application because they have suitable excitation and emission wavelengths and stable optical properties in a high temperature environment. High brightness warm-white LED lamps have been realized using a yellowish-orange α-SiAlON oxynitride phosphor. High color-rendering index white LED lamps have been also realized using three color oxynitride/nitride phosphors.

A polarization-independent liquid crystal (LC) grating with a microscale LC molecular alignment pattern is proposed. The microscale LC alignment pattern is achieved using a microrubbing technique. The optical properties of the proposed LC grating are theoretically discussed in detail using Jones matrix method. Optimum condition for obtaining maximum +1st or -1st diffraction efficiencies is derived. The diffraction efficiency of the LC grating is measured and the diffraction efficiency characteristics are compared with the theoretical result. Furthermore, the dependence of the polarization direction of the incident light on the diffraction efficiency is discussed.

Recently, there are so many researches on Autonomous Distributed Manufacturing Systems (ADMSs), where cooperation among agents is used to solve problems, such as the scheduling problem and the vehicle routing problem. We target ADMSs where an ADMS consists of two sub-systems: a Production System (PS) and an Autonomous Transportation System (ATS). This paper discusses an on-line Tasks Assignment and Routing Problem (TARP) for ATSs under conditions of given production schedule and finite buffer capacity. The TARP results in a constrained version of the Pickup and Delivery Problem with Time Windows (PDPTW), and this paper gives a mathematical formulation of the problem. This paper, also, proposes a cooperative algorithm to obtain suboptimal solutions in which no deadlocks and buffer overflows occur. By computational experiments, we will examine the effectiveness of the proposed algorithm. Computational experiments show that the proposed algorithm is able to obtain efficient and deadlock-free routes even though the buffer capacity is less.

A sampling frequency offset estimation scheme for MB-OFDM UWB systems is proposed based on technical specification and multi-band utilization of the MB-OFDM. An estimation scheme using simple weighting factor based on the received signal power of each sub-channel is also introduced to efficiently combine estimates obtained from all the sub-carriers and to improve the estimation performance.

Timing optimization is an important goal of global routing in deep submicron era. To guarantee the timing performance of the circuit, merely adopting topology optimization becomes inadequate. In this paper, we present an efficient timing-driven global routing algorithm with buffer insertion. Our approach is capable of applying topological-based timing optimization and buffer insertion simultaneously with routablity considerations. Compared with previous works, we efficiently solve the timing issues under a limited buffer usage. The experimental results have demonstrated significant delay improvement within short runtime with very small number of buffers inserted.

In this paper, a three-way divider is proposed for a partially-corporate feed in an alternating phase-fed single-layer slotted waveguide array. The divider is placed at the middle of the feed waveguide and reduces the long line effects; the frequency bandwidth is doubled. It is a kind of cross junction with one input port and three output ports; most of the power is equally divided into the right and left halves of the feed waveguide while the rest of power goes straight into the center radiating waveguide. Based upon the moment method design of the three-way divider, an inductive post is introduced for wide band power dividing control to the radiating waveguide. Reflection is below -20 dB over a wide bandwidth of 24.3-26.3 GHz, and the range of power dividing ratio ranges from 1/43 to 1/4. The amplitude and the phase from the two output ports to the feed waveguide are well balanced, and the differences are less than 0.1 dB and 5.0 degrees, respectively. The MoM analysis and the wide band design are verified experimentally in the 4 GHz band.

In this paper, we propose a parametric model checking algorithm for a subclass of Timed Automata called Parametric Time-Interval Automata (PTIA). In a PTIA, we can specify upper- and lower-bounds of the execution time (time-interval) of each transition using parameter variables. The proposed algorithm takes two inputs, a model described in a PTIA and a property described in a PTIA accepting all invalid infinite/finite runs (called a never claim), or valid finite runs of the model. In the proposed algorithm, firstly we determinize and complement the given property PTIA if it accepts valid finite runs. Secondly, we accelerate the given model, that is, we regard all the actions that are not appeared in the given property PTIA as invisible actions and eliminate them from the model while preserving the set of visible traces and their timings. Thirdly, we construct a parallel composition of the model and the property PTIAs which is accepting all invalid runs that are accepted by the model. Finally, we perform the extension of Double Depth First Search (DDFS), which is used in the automata-theoretic approach to Linear-time Temporal Logic (LTL) model checking, to derive the weakest parameter condition in order that the given model never executes the invalid runs specified by the given property.

Time-Division-Multiplexing (TDM) is usually aimed at digital signals, while Continuous Wave Time-Division- Multiplexing (i.e. CWTDM) presented in this paper mainly addresses the problem of multiple continuous signals to share a channel. According to the idea in Ref.[1], this paper proposes a novel method for implementing CWTDM, which can make multiple band-limited continuous signals time-division-multiplexed into one continuous signal without significantly expanding the frequency band. The new method has several important applications. In particular, it can be used to implement an on-board FDMA-CWTDM conversion to develop a new system of satellite communications with more efficient performance.

A rack-mounted DC power-supply system utilizing Li-ion batteries, which have higher energy density than conventional VRLA batteries, was developed. The system was designed to have the management functions of Li-ion batteries, such as overcharge protection, over-discharge protection, and cell-voltage equalization, by taking operational requirements into consideration. The volume and weight of the entire system were decreased to one-fourth and three-fifths, respectively, of the volume and weight of a conventional system, making the proposed system ideal as a high-energy-density backup power supply. The functions, system configuration, and characteristics of this rack-mounted DC power supply system utilizing Li-ion batteries are described.