A novel Adaptive Resource-based Probabilistic Search algorithm (ARPS) for P2P networks is proposed in this paper. ARPS introduces probabilistic forwarding for query messages according to the popularity of the resource being searched. A mechanism is introduced to estimate the popularity and adjust the forwarding probability accordingly such that a tradeoff between search performance and cost can be made. Using computer simulations, we compare the performance of ARPS with several other search algorithms. It is shown that ARPS performs well under various P2P scenarios. ARPS guarantees a success rate above a certain level under all circumstances, and enjoys high and popularity-invariant search success rate. Furthermore, ARPS adapts well to the variation of popularity, resulting in high efficiency and flexibility.

Several structured peer-to-peer networks have been created to solve the scalability problem of previous peer-to-peer systems such as Gnutella and Napster. These peer-to-peer networks which support distributed hash table functionality construct a sort of structured overlay network, which can cause a topology mismatch between the overlay and the underlying physical network. To solve this mismatch problem, we propose a topology-aware hierarchical overlay framework for DHTs. The hierarchical approach for the overlay is based on the concept that the underlying global Internet is also a hierarchical architecture, that is, a network of networks. This hierarchical approach for the overlay puts forth two benefits: finding data in a physically near place with a high probability, and smaller lookup time. Our hierarchical overlay framework is different from other hierarchical architecture systems in a sense that it provides a specific self-organizing grouping algorithm. Our additional optimization schemes complete the basic algorithm which constructs a hierarchical structure without any central control.

This paper proposes the P-1 radiation model for the calculation of low voltage arc plasma. The influence of both emission and self-absorption are taken into account in this model. Based on the couple of electric field, magnetic field, flow field and thermal field, a three-dimensional arc chamber model is constructed and its radiation energy is calculated by the P-1 model with the spectrum divided into six bands. From the obtained distributions of temperature, incident radiation intensity, plasma velocity and current density by P-1 model, it is observed that temperature is obviously different from the result by net emission coefficient (NEC) method in the low temperature region. Arc column edges near the arc root also absorb radiation energy. Furthermore, compared with the result by NEC method, the arc column voltage calculated by P-1 model is lower and more close to the experimental result.

We propose the "Two-Step Search scheme with Linear search based Second step (TSS-LS)" by improving the conventional "Two-Step Search scheme with Bit reversal search based Second step (TSS-BS)" for reliable as well as rapid acquisition of Ultra Wide Band (UWB) signals in multipath channels. The proposed TSS-LS utilizes two different thresholds and search windows to achieve fast acquisition. Furthermore, unlike the TSS-BS in which the bit reversal algorithm is applied in both steps, the linear search is adopted for the second step in the proposed TSS-LS to correctly find the starting point in the range of effective delay spread of the multipath channels, and to obtain reliable bit error rate performance of the UWB systems.

The sputter erosion of arcing contacts is a very complex phenomenon, which is determined by the interaction between electromagnetic force, heat conduction and surface tension of liquid metal. A new model for evaluating the sputter erosion of electrodes is described in this paper, which is based on the electromagnetic forces against the molten pool, flowing velocity, kinetic energy and the surface tension of the molten pool. Erosion tests on AgSnO2, AgNi10 and AgNi0.15 contacts under the loads of resistance, lamp and inductance respectively at 14 VDC have been carried out. Experimental results indicate good agreement with the model's simulation. The model shows how the current and density, specific heat and other parameters of material affect the erosion rate.

We propose a novel clustering scheme considering non-uniform correlation distribution derived by experimental environment property. Firstly, we investigate the entropy property of actual environment, and then show that its spatial correlation is not uniformly distributed. Based on this result, we present the clustering strategy which provides the efficient data aggregation. Through the simulation under the non-uniform correlation distribution, we show the advantage of the proposed scheme in terms of the energy consumption property per node and the network lifetime.

We propose a recursive clustering and order restriction (R-CORE) method for learning large-scale Bayesian networks. The proposed method considers a reduced search space for directed acyclic graph (DAG) structures in scoring-based Bayesian network learning. The candidate DAG structures are restricted by clustering variables and determining the intercluster directionality. The proposed method considers cycles on only cmax(«n) variables rather than on all n variables for DAG structures. The R-CORE method could be a useful tool in very large problems where only a very small amount of training data is available.

The dependence of arcing duration and energy in break operations for automotive relays was analysed with breaking current/voltage waveforms. Endurance tests were conducted with AgSnO2, AgNi10 and AgNi0.15 contacts under the loads of resistance, lamp and inductance, respectively, at 14 VDC. The experimental results shows breaking current (or break arc) duration is usually low and stable before welding occurs. The welding may appear suddenly or randomly without any preceding cumulated increases in the arc duration, the quantity of electric charges, nor the arcing energy. The welded contacts may be re-opened in the later break operation and, thereafter, can keep on working normally for many times.

A two-dimensional compressible magnetohydrodynamic (MHD) computational model has been developed to study the effect of gassing material on air arc behavior in low voltage circuit breaker. The properties of arc plasma and the electric, magnetic and radiative phenomena have been taken into account in the model. Based on the model, steady state solutions have been performed to study the effect of gassing material on the arc radius and electric field in the arc column. Then, the effect of gassing material on the transient process of arc motion also has been simulated. In addition, using the two-dimensional optical fiber measurement system, experiments have been done to measure the average velocity of arc motion with one model chamber and to verify the simulation model and prediction results. It demonstrates that the action of gassing material may yield the stronger electric field, less arc radius and higher arc motion velocity.

Ag and Pd electrical contact pairs are separated at constant separating speeds (5, 10 and 20 mm/s) in a DC 42 V/8.4 A resistive circuit. The motion of the breaking arc is observed with a high-speed video camera. For Ag contacts, the motion of the breaking arc becomes stable at a certain critical gap at separating speeds of 10 mm/s and 20 mm/s, and the breaking arc moves extensively at the separating speed of 5 mm/s. For Pd contacts, the breaking arc moves extensively regardless of the separating speed. These results are attributed to the following causes. For Ag contacts, the difference in the motion of arc spots at each separating speed is changed by the difference in the total energy input to the contacts. For Pd contacts, the temperature of the contact surfaces is kept high because of the lower thermal conductivity of Pd than Ag.

The paper presents a method for testing transport of composite contacts materials under electrical arc conditions at high currents and for polarized electrodes. Tests and the discussion of results were carried out for silver-metal, silver-metal oxide and silver-tungsten carbide contact materials. Additionally, tungsten electrode was used as the second contact which was either cathode or anode. Spectrometric analysis of arc erosion components transported onto the second electrode and into the surroundings was carried out.

The purpose of our study is to develop an algorithm that would enable the automated detection of lacunar infarct on T1- and T2-weighted magnetic resonance (MR) images. Automated identification of the lacunar infarct regions is not only useful in assisting radiologists to detect lacunar infarcts as a computer-aided detection (CAD) system but is also beneficial in preventing the occurrence of cerebral apoplexy in high-risk patients. The lacunar infarct regions are classified into the following two types for detection: "isolated lacunar infarct regions" and "lacunar infarct regions adjacent to hyperintensive structures." The detection of isolated lacunar infarct regions was based on the multiple-phase binarization (MPB) method. Moreover, to detect lacunar infarct regions adjacent to hyperintensive structures, we used a morphological opening processing and a subtraction technique between images produced using two types of circular structuring elements. Thereafter, candidate regions were selected based on three features -- area, circularity, and gravity center. Two methods were applied to the detected candidates for eliminating false positives (FPs). The first method involved eliminating FPs that occurred along the periphery of the brain using the region-growing technique. The second method, the multi-circular regions difference method (MCRDM), was based on the comparison between the mean pixel values in a series of double circles on a T1-weighted image. A training dataset comprising 20 lacunar infarct cases was used to adjust the parameters. In addition, 673 MR images from 80 cases were used for testing the performance of our method; the sensitivity and specificity were 90.1% and 30.0% with 1.7 FPs per image, respectively. The results indicated that our CAD system for the automatic detection of lacunar infarct on MR images was effective.

The realization of k-nearest-matches search capability in fully-parallel mixed digital-analog associative memories by a sequential autonomous search mode is reported. The proposed concept and circuit implementation can be applied with all types of distance measures such as Hamming, Manhattan or Euclidean distance search, and the k value can be freely selected during operation. A test chip for concept verification has been designed in 0.35 µm CMOS technology with two-poly, three-metal layers, realizes k-nearest-matches Euclidean distance search and consumes 5.12 mm2 of the chip area for 64 reference patterns each with 16 units of 5-bit.

In this paper, we propose a stochastic dynamic local search (SDLS) method for Multiple-Valued Logic (MVL) learning by introducing stochastic dynamics into the traditional local search method. The proposed learning network maintains some trends of quick descent to either global minimum or a local minimum, and at the same time has some chance of escaping from local minima by permitting temporary error increases during learning. Thus the network may eventually reach the global minimum state or its best approximation with very high probability. Simulation results show that the proposed algorithm has the superior abilities to find the global minimum for the MVL network learning within reasonable number of iterations.

In July 2006, International Telecommunication Union-Telecommunication Standardization Sector (ITU-T) Study Group 13 initiated the approval process for a batch of framework Recommendations on the Next Generation Network (NGN) Release 1. One of the new Recommendations, Y.2012, illustrates the NGN from the viewpoint of a functional architecture consisting of various functional blocks, namely functional entities. In conjunction with this Recommendation, this paper explains how the NGN can be built and how the NGN utilizes functional entities to provide expected services and required capabilities. This paper also identifies open issues for extending the functional architecture towards Release 2.

In this paper we focus on building a large scale keyword search service over structured Peer-to-Peer (P2P) networks. Current state-of-the-art keyword search approaches for structured P2P systems are based on inverted list intersection. However, the biggest challenge in those approaches is that when the indices are distributed over peers, a simple query may cause a large amount of data to be transmitted over the network. We propose in this paper a new P2P keyword search scheme, called "Proof," which aims to reduce the network traffic generated during the intersection process. We applied three main ideas in Proof to reduce network traffic, including (1) using a sorted query flow, (2) storing content summaries in the inverted lists, and (3) setting a stop condition for the checking of content summaries. We also discuss the advantages and limitations of Proof, and conducted extensive experiments to evaluate the search performance and the quality of search results. Our simulation results showed that, compared with previous solutions, Proof can dramatically reduce network traffic while providing 100% precision and high recall of search results, at some additional storage overhead.

To drastically reduce the power dissipation (P) of an absolute difference accumulation (ADA) circuit for H.26x/MPEG4 motion estimation, a fast block-matching (BM) algorithm called the Multiple Block-matching Step (MBS) algorithm has been developed. The MBS algorithm can drastically improve the block matching speed, while achieving the same visual quality as that of a full search (FS) BM algorithm. Power dissipation (P) of a 0.18-µm CMOS absolute difference accumulator (ADA) circuit employing the MBS algorithm is significantly reduced to the range of about 0.3% to 12% that of the same ADA circuit adopting FS.

Recently, self-reconfigurable devices which can be partially reprogrammed by other part of the same device have been proposed. However, since conventional self-reconfigurable devices are LUT-array-based fine-grained devices, their time efficiency is spoiled by overhead for reconfiguration time to load large amount of configuration data. Therefore, we have to improve architectures. At the architecture design phase, it is difficult to estimate the performance, including reconfiguration overhead, of self-reconfigurable devices by static analysis, since it depends on many architecture parameters and unpredictable run-time behavior. In this paper, we propose a simulation-based platform for design exploration of self-reconfigurable devices. As a demonstration of the proposed platform, we implement an adaptive load distribution model on the devices of various reconfiguration granularities and evaluate performance of the devices.

A fully integrated broadband up-conversion mixer with low power consumption is demonstrated on 90 nm CMOS technology in this paper. This mixer has a single-ended input and a multi-layer stacked Marchand balun is used for converting the differential output of the single-balanced mixer topology to a single-ended output. This balun employs inductive coupling between two metal layers and includes slotted shields to reduce substrate losses. The circuit size is 650 µm570 µm. At 22.1 GHz, the integrated mixer achieves a conversion gain of 2 dB with a maximum power dissipation of only 11.1 mW from a 1.2 V dc power supply at LO power of 5 dBm. Input referred 1-dB compression point is -14.8 dBm. The LO and RF return loss are better than 10 dB for frequencies between 20-26 GHz.

Cache performance optimization is an important design consideration in building high-performance embedded processors. Unlike general-purpose microprocessors, embedded processors can take advantages of application-specific information in optimizing the cache performance. One of such examples is to use modified cache index bits (over conventional index bits) based on memory access traces from key target embedded applications so that the number of conflict misses can be reduced. In this paper, we present a novel fine-grained cache reconfiguration technique which allows an intra-program reconfiguration of cache index bits, thus better reflecting the changing characteristics of a program execution. The proposed technique, called dynamic reconfiguration of index bits (DRIB), dynamically changes cache index bits in the function level. This compiler-directed and fine-grained approach allows each function to be executed using its own optimal index bits with no additional hardware support. In order to avoid potential performance degradation by frequent cache invalidations from reconfiguring cache index bits, we describe an efficient algorithm for selecting target functions whose cache index bits are reconfigured. Our algorithm ensures that the number of cache misses reduced by DRIB outnumbers the number of cache misses increased from cache invalidations. We also propose a new cache architecture, Two-Level Indexing (TLI) cache, which further reduces the number of conflict misses by intelligently dividing indexing steps into two stages. Our experimental results show that the DRIP approach combined with the TLI cache reduces the number of cache misses by 35% over the conventional cache indexing technique.