This paper first examines the issues related to scheduling loop applications on a software distributed shared memory (DSM) system. Then, a dynamic scheduling scheme is developed based on the examined issues to enhance the performance of loop applications on DSM. Compared with previous works, the proposed scheme has several specialties. The first is that the workload of processors can be effectively balanced even when the computational capabilities of processors and the computational needs of threads are not identical. The second is it divides thread mapping into two phases, each with one consideration, i.e., load balance or communication cost, and adopts thread migration and exchange in the two phases, respectively. The third is the exploitation of data sharing among threads to reduce data-consistency communication, and the last is to attack the negative effect of the unnecessary inter-node sharing caused by thread re-mapping. The proposed scheme has been implemented on a page-based DSM system called Cohesion. Our experiments show that the proposed scheme is more effective to improve the performance of the test programs than related schemes.

This paper presents a three-dimensional polarimetric detection result of targets buried in snowpack by synthetic aperture FM-CW radar system. Since the FM-CW radar is suitable for short range sensing and can be equipped with fully polarimetric capability, we further extended it to a polarimetric three-dimensional SAR system. A field experiment was carried out to image and detect targets in a natural snowpack of 280 cm deep. The polarimetric detection and identification schemes are the polarimetric filtering, three-component decomposition, and the power polarization anisotropy coefficient. These approaches to acquired data show the usefulness of three-dimensional polarimetric FM-CW SAR system.

In this paper, the effective uses of Gerschgorin radii of the similar transformed covariance matrix for source number estimation are introduced. A heuristic approach is used for developing the detection criteria. The heuristic approach applying the visual Gerschgorin disk method (VGD), developed from the projection concept, overcomes the problems in cases of small data samples, an unknown noise model, and data dependency. Furthermore, Gerschgorin disks can be formed into two distinct, non-overlapping collections; one for signals and the other for noises. The number of sources can be visually determined by counting the number of Gerschgorin disks for signals. The proposed method is based on the sample correlation coefficient to normalize the signal Gerschgorin radii for source number detection. The performance of VGD shows improved detection capabilities over Gerschgorin Disk Estimator (GDE) in Gaussian white noise process and was used successfully in measured experimental data.

In this letter, we remark a well-known nonlinear filtering technique realize immediate effect to suppress the influence of the additive measurement noise in the input to a set theoretic linear blind deconvolution scheme. Numerical examples show ε-separating nonlinear pre-filtering techniques work suitably to this noisy blind deconvolution problem.

In this paper we develop a CORDIC-based floating-point vectoring algorithm which reduces significantly the amount of microrotation steps as compared to the conventional algorithm. The overhead required to accomplish this is minimized by the introduction of an angle selection function which considers only a few of the total amount of bits used to represent the vector being rotated. At the same time, the cost of individual microrotations is kept low by the utilization of a fast rotations angle base.

A repeating watermarking technique based on visual secret sharing (VSS) scheme provides the watermark repeated throughout the image for avoiding the image cropping. In this paper, the watermark is divided into public watermark and secret watermark by using the VSS scheme to improve the security of the proposed watermarking technique. Unlike the traditional methods, the original watermark does not have to be embedded into the host image directly and, thus, it is hard to be detected or removed by the pirates or hackers. The retrieved watermark extracted from the watermarked image does not require the complete original image, but requires a secret watermark. Furthermore, the watermarking technique suits the watermark with an adaptive size of binary image for designing the watermarking system. The experimental results show that the proposed method can withstand the common image processing operations, such as filtering, lossy compression and the cropping attacking etc. The embedded watermark is imperceptible, and that the extracted watermark identifies clearly the owner's copyright.

The optimization of channel assignment in cellular mobile networks is an NP-complete combinatorial optimization problem. For any reasonable size network, only sub-optimal solutions can be obtained by heuristic algorithms. In this paper, six channel assignment heuristic algorithms are proposed and evaluated. They are the combinations of three channel assignment strategies and two cell ordering methods. What we found are (i) the node-color ordering of cells is a more efficient ordering method than the node-degree ordering; (ii) the frequency exhaustive strategy is more suitable for systems with highly non-uniformly distributed traffic, and the requirement exhaustive strategy is more suitable for systems with less non-uniformly distributed traffic; and (iii) the combined frequency and requirement exhaustive strategy with node-color re-ordering is the most efficient algorithm. The frequency spans obtained using the proposed algorithms are much lower than that reported in the literature, and in many cases are equal to the theoretical lower bounds.

The use of intelligent agents is on the rise, fueled by the unprecedented growth in the Internet and web based applications. Consequently, agent-oriented software is becoming large and complex. To support a systematic development of such software, an agent-oriented software development methodology is necessary. This paper focuses on the modeling phase of agent-oriented software life cycle and, presents an approach for agent modeling consisting of Agent Elicitation, Intra, and Inter Agent modeling methods. Agent Elicitation deals with identifying and extracting agents from "classes" in the real world. Intra Agent Modeling involves expressing agent characteristics - Goal, Belief, Plan and Capability - whereas, Inter Agent modeling incorporates agent mobility and communication in a multi-agent system.

An experiment was conducted to measure and compare the physiological effects of three types of CRT on users. We proposed a new strategy for measuring the user's level of relaxation. In this strategy, called "Task Break Monitoring (TBM)," the subjects took a break with eyes closed after each interaction with the computer. During each break, electroencephalogram (EEG), especially alpha 1 waves, electrocardiogram (ECG) and galvanic skin resistance (GSR) were monitored and recorded. The results show that the type of CRT display which emits far-infrared rays modulated by a FIR-fan induce less fatigue in users while they are working and reduce the recovery time after the task was completed. We believe "TBM" to be an important innovation in human computer research and development because the after effects of computer use have an obvious bearing on recovery time, user endurance and psychological attitude to the technology in general etc.

This paper has two parts. In the first part of the paper, we note the property that under the para perspective camera projection model of a camera, the set of 2D images produced by a 3D point can be optimally represented by two lines in the affine space (α-β space). The slope of these two lines are same, and we observe that this constraint is exactly the same as the epipolar line constraint. Using this constraint, the equation of the epipolar line can be derived. In the second part of the paper, we use the "same slope" property of the lines in the α-β space to derive the affine structure of the human face. The input to the algorithm is not limited to an image sequence of a human head under rigid motion. It can be snapshots of the human face taken by the same or different cameras, over different periods of time. Since the depth variation of the human face is not very large, we use the para perspective camera projection model. Using this property, we reformulate the (human) face structure reconstruction problem in terms of the much familiar multiple baseline stereo matching problem. Apart from the face modeling aspect, we also show how we use the results for reprojecting human faces in identification tasks.

The visual inspection of printed circuit boards (PCBs) at the final production stage is necessary for quality assurance and the requirements for an automated inspection system are very high. However, consistent inspection of patterns on these PCBs is very difficult due to pattern complexity. Most of the previously developed techniques are not sensitive enough to detect defects in complex patterns. To solve this problem, we propose a new optical system that discriminates pattern types existing on a PCB, such as copper, solder resist and silk-screen printing. We have also developed a hybrid defect detection technique to inspect discriminated patterns. This technique is based on shape measurement and features extraction methods. We used the proposed techniques in an actual automated inspection system, realizing real time transactions with a combination of hardware equipped with image processing LSIs and PC software. Evaluation with this inspection system ensures a 100% defect detection rate and a fairly low false alarm rate (0.06%). The present paper describes the inspection algorithm and briefly explains the automated inspection system.

Scheduling directed a-cyclic task graphs (DAGs) onto multiprocessors is known to be an intractable problem. Although there have been several heuristic algorithms for scheduling DAGs onto multiprocessors, few address the mapping onto a given number of completely connected processors with an objective of minimizing the finish time. We present an efficient algorithm called ClusterMerge to statically schedule directed a-cyclic task graphs onto a homogeneous completely connected MIMD system with a given number of processors. The algorithm clusters tasks in a DAG using a longest path heuristic and then iteratively merges these clusters to give a number of clusters identical to the number of available processors. Each of these clusters is then scheduled on a separate processor. Using simulations, we demonstrate that ClusterMerge schedules task graphs yielding the same or lower execution times than those of other researchers, but using fewer processors. We also discuss pitfalls in the various approaches to defining the longest path in a directed a-cyclic task graph.

In this paper, we propose a combination system of point to multipoint (P-MP) time division multiple access (TDMA) broadband wireless access (BWA) system and indoor wireless local area network (WLAN). In order to realize a high speed wireless communication, a wide bandwidth is required for both access lines and local area networks. The proposed system shares the frequency between BWA and WLAN to achieve an efficient use of frequency resources. This is based on the idea that an uplink band of the P-MP TDMA BWA system will provide relatively small interference slots, which are not used by subscriber stations nearby. In other words, there are useful small interference slots for another system using same frequency according to its position. Then we use such small interference slots for WLAN. In addition, direct sequence code division multiple access (DS-CDMA) can suppress such TDMA interference by spreading it over wide bandwidth. Therefore in the proposed system, DS-CDMA is used for WLAN in the same band with the BWA uplink. We also discuss WLAN packet error rate reduction techniques for this system. To confirm the availability of the proposed system, we evaluate the system performance by numerical analysis and computer simulation.

This paper presents a heuristic graph coloring algorithm named MIPS_CLR, a MInimal-state Processing Search algorithm for the graph CoLoRing problem. Given a graph G(V, E), the goal of this NP-complete problem is to find a color assignment to every vertex in V such that any pair of adjacent vertices must not receive the same color but also the total number of colors should be minimized. The graph coloring problem has been widely studied due to its large number of practical applications in various fields. In MIPS_CLR, a construction stage first generates an initial minimal state composed of as many as colored vertices by a simple greedy algorithm, after a maximal clique of G is found by a maximum clique algorithm. Then, a refinement stage iteratively seeks a solution state while keeping minimality in terms of a cost function by a minimal-state transition method. In this method, the schemes of a best color selection, a random color selection, a color assignment shuffle, and a gradual color expansion are used together to realize the discrete descent search with hill-climbing capabilities. The performance of MIPS_CLR is evaluated through solving DIMACS benchmark graph instances, where the solution quality is generally better than existing algorithms while the computation time is comparable with the best existing one. In particular, MIPS_CLR provides new lower bound solutions for several instances. The simulation results confirm the extensive search capability of our MIPS_CLR approach for the graph coloring problem.

Saltiness elicited by salt is one of the basic tastes. However, components of salt on the market differ depending on manufacturing processes and its taste as well. Salt manufactured by ion-exchange membrane process is composed of more than 99% pure sodium chloride, while bay salt contains trace coexisting components. Despite reports on sensory evaluation, the differences in taste are still uncertain because of a small amount of coexisting components. We studied the taste of salt with trace coexisting components; the bittern ("nigari" in Japanese) was evaluated objectively and quantitatively using a multichannel taste sensor with lipid/polymer membranes. A taste sensor is comprised of several types of lipid/polymer membranes for transforming information of taste substances into electric signals. The model samples were composed of sodium chloride and trace coexisting components such as magnesium sulfate, magnesium chloride, calcium chloride and sodium chloride. The taste sensor clearly discriminated each sample according to the response patterns. Based on the sensor outputs, we evaluated the taste by means of the combination of principal component analysis and ionic strength. The results show the taste of salt with nigari has a correlation with ionic strength.

A new method for measuring the scattering coefficient using a metal-plate reflector was developed in order to provide a non-destructive way for the assessment of microwave materials in free space. By displacing the position of the metal-plate reflector on the specimen to be tested, the incident wave and the scattered wave from the measured area were determined without the influence of extraneous waves such as the direct coupling between transmitting and receiving antennas and scattered waves from background objects. Because the behavior of a metal-plate reflector is similar to that of an optical shutter in optics, our new scattering measurement system enables us to measure both backward- and forward-scattering coefficients of small regions of the specimen for various types of materials in a non-destructive manner. Our study examined the metal-plate size dependence of the complex reflection and transmission coefficients of some dielectric sheet samples. The measured data indicated that the reflection and transmission coefficients of a Bakelite flat plate and Styrofoam sheet were constant for various sizes of metal plates at the X-band.

This paper deals with the scattering of a TE plane wave by an apodised sinusoidal surface. The analysis starts with the extended Floquet solution, which is a 'Fourier series' with 'Fourier coefficients' given by band-limited Fourier integrals of amplitude functions. An integral equation for the amplitude functions is derived and solved by the small perturbation method to get single and double scattering amplitudes. Then, it is found that the beam shape generated by the single scattering is proportional to the Fourier spectrum of the apodisation function, but that generated by the double scattering is proportional to the spectrum of the squared apodisation. As a result, the single scattering beam and the double scattering beam may have different sidelobe patterns. It is demonstrated that the sidelobes are much reduced if Hanning window or Hamming window is used as an apodisation function.

In this paper we consider the k-clustering problem for a set S of n points pi=(xi) in the d-dimensional space with variance-based errors as clustering criteria, motivated from the color quantization problem of computing a color lookup table for frame buffer display. As the inter-cluster criterion to minimize, the sum of intra-cluster errors over every cluster is used, and as the intra-cluster criterion of a cluster Sj, |Sj|α-1 Σpi Sj ||xi - - x (Sj)||2 is considered, where |||| is the L2 norm and - x (Sj) is the centroid of points in Sj, i. e. , (1/|Sj|)Σpi Sj xi. The cases of α=1,2 correspond to the sum of squared errors and the all-pairs sum of squared errors, respectively. The k-clustering problem under the criterion with α = 1,2 are treated in a unified manner by characterizing the optimum solution to the k-clustering problem by the ordinary Euclidean Voronoi diagram and the weighted Voronoi diagram with both multiplicative and additive weights. With this framework, the problem is related to the generalized primary shatter function for the Voronoi diagrams. The primary shatter function is shown to be O(nO(kd)), which implies that, for fixed k, this clustering problem can be solved in a polynomial time. For the problem with the most typical intra-cluster criterion of the sum of squared errors, we also present an efficient randomized algorithm which, roughly speaking, finds an ε-approximate 2-clustering in O(n(1/ε)d) time, which is quite practical and may be used to real large-scale problems such as the color quantization problem.

In a multihop network, radio packets are often relayed through inter-mediate stations (repeaters) in order to transfer a radio packet from a source to its destination. We consider a scheduling problem in a multihop network using a graphtheoretical model. Let D=(V,A) be the digraph with a vertex set V and an arc set A. Let f be a labeling of positive integers on the arcs of A. The value of f(u,v) means a frequency band assigned on the link from u to v. We call f antitransitive if f(u,v)f(v,w) for any adjacent arcs (u,v) and (v,w) of D. The minimum antitransitive-labeling problem is the problem of finding a minimum antitransitive-labeling such that the number of integers assigned in an antitransitive labeling is minimum. In this paper, we prove that this problem is NP-hard, and we propose a simple distributed approximation algorithm for it.

This paper introduces the construction of a family of complex-valued scaling functions and wavelets with symmetry/antisymmetry, compact support and orthogonality from the Daubechies polynomial, and applies them to solve electromagnetic scattering problems. For simplicity, only two extreme cases in the family, maximum-localized complex-valued wavelets and minimum-localized complex-valued wavelets are investigated. Regularity of root location of the Daubechies polynomial in spectral factorization are also presented to construct these two extreme genus of complex-valued wavelets. When wavelets are used as basis functions to solve electromagnetic scattering problems by the method of moment (MoM), they often lead to sparse matrix equations. We will compare the sparsity of MoM matrices by the real-valued Daubechies wavelets, minimum-localized complex-valued Daubechies and maximum-localized complex-valued Daubechies wavelets. Our research summarized in this paper shows that the wavelets with smaller signal width will result in a more sparse MoM matrix, especially when the scatterer is with many corners.