In many parallel programs, run-time array redistribution is usually required to enhance data locality and reduce remote memory access on the distributed memory multicomputers. In general, array distribution can be classified into regular distribution and irregular distribution according to the distribution fashion. Many methods for performing regular array redistribution have been presented in the literature. However, for the heterogeneous computation environment, irregular array redistributions can be used to adjust data assignment at run-time. In this paper, an Essential Cycle Calculation method for unequal block sizes array redistribution is presented. In the ECC method, a processor first computes the source/destination processor/data sets of array elements in the first essential cycle of the local array it owns. From the source/destination processor/data sets of array elements in the first essential cycle, we can construct packing/unpacking pattern tables. Since each essential cycle has the same communication pattern, based on the packing/unpacking pattern tables, a processor can pack/unpack array elements efficiently. To evaluate the performance of the ECC method, we have implemented this method on an IBM SP2 parallel machine and compare it with the Sequence method. The cost models for these methods are also presented. The experimental results show that the ECC method greatly outperforms the Sequence method for all test samples.

A mobile ad hoc network (MANET) is a self-organizing and adaptive wireless network constructed by the dynamic gathering of mobile nodes (MNs). The communication among MNs in MANETs is carried out without base stations or access points and the transmission of data packets is completed through relays among nodes. Due to the mobility of MNs, the topology of a MANET frequently changes and thus results in the disability of on-the-fly data transmission routes. To cope with the intrinsic properties of MANETs, Dynamic Backup Routes Routing Protocol (DBR2P), a distributed backup routes mechanism for quick reconnection during link failures, is proposed in this paper. DBR2P is an on-demand routing protocol which can set up many backup routes to reach a destination node in a given period of time. The information of backup routes can be saved in a specific on-the-route node and enables backup routes to be found immediately in situation regarding disconnection. When a link fails, routes from the source node to the destination node are analyzed to obtain backup routes and to sustain quick reconnection. As a result, DBR2P could more thoroughly improve the quality of routing than previous routing protocols.

Multi-projector technology has been under consideration in recent years. This technology allows the generation of wide field of view and high-resolution images in a cost-effective manner. It is expected to be applied extensively to training simulators where vivid immersive sensations and precision are required. However, in many systems the viewing frustums cannot be automatically assigned for distributed rendering, and the required manual setup is complicated and difficult. This is because the camera should be coincide exactly with a desired eye point to avoid perspective distortions. For the actual applications, the camera is seldom able to be set up at the desired eye point because of physical constraints, e.g., a narrow cockpit with many instruments. To resolve this issue, we have developed a "virtual camera method" that yields high-precision calibration regardless of the camera position. This method takes advantage of the quadratic nature of the display surface. We developed a practical real-time multi-projector display system for applications such as training simulators, that require high-accuracy in geometry and rapid response time.

This paper presents a way of using a linear regression model to produce a single-valued criterion that indicates the perceived importance of each block in a stream of speech blocks. This method is superior to the conventional approach, voice activity detection (VAD), in that it provides a dynamically changing priority value for speech segments with finer granularity. The approach can be used in conjunction with scalable speech coding techniques in the context of IP QoS services to achieve a flexible form of quality control for speech transmission. A simple linear regression model is used to estimate a mean opinion score (MOS) of the various cases of missing speech segments. The estimated MOS is a continuous value that can be mapped to priority levels with arbitrary granularity. Through subjective evaluation, we show the validity of the calculated priority values.

Since sentences are the basic propositional units of text, knowing their themes should help in completing various tasks such as automatic summarization requiring the knowledge about the semantic content of text. Despite the importance of determining the theme of a sentence, however, few studies have investigated the problem of automatically assigning a theme to a sentence. In this paper, we examine the notion of sentence theme and propose an automatic scheme where head-driven patterns are used for theme assignment. We tested our scheme with sentences in encyclopedia articles and obtained a promising result of 98.96% in F-score for training data and 88.57% for testing data, which outperform the baseline using all but the head-driven patterns.

To find the best transformation between a "model" point set and an "image" point set is the main purpose of point pattern matching. The similarity measure plays a pivotal role and is used to determine the degree of resemblance between two objects. Although some well-known Hausdorff distance measures work well for this task, they are very computationally expensive and suffer from the noise points. In this paper, we propose a novel similarity measure using the Hilbert curve named Hilbert scanning distance (HSD) to resolve the problems. This method computes the distance measure in the one-dimensional (1-D) sequence instead of in the two-dimensional (2-D) space, which greatly reduces the computational complexity. By applying a threshold elimination function, large distance values caused by noise and position errors (e.g. those that occur with feature or edge extraction) are removed. The proposed algorithm has been applied to the task of matching edge maps with noise. The experimental results show that HSD can provide sufficient information for image matching within low computational complexity. We believe this sets a new direction for the research of point pattern recognition.

This paper presents new algorithms for the Tate pairing on a prime field. Recently, many pairing-based cryptographic schemes have been proposed. However, computing pairings incurs a high computational cost and represents the bottleneck to using pairings in actual protocols. This paper shows that the proposed algorithms reduce the cost of multiplication and inversion on an extension field, and reduce the number of calculations of the extended finite field. This paper also discusses the optimal algorithm to be used for each pairing parameter and shows that the total computational cost is reduced by 50% if k = 6 and 57% if k = 8.

We have proposed Rate-based Multi-path Transmission Control Protocol (R-M/TCP) for improving reliability and performance of data transfer over the Internet by using multiple paths. Congestion control in R-M/TCP is performed in a rate-based and loss-avoidance manner. It attempts to estimate the available bandwidth and the queue length of the used routes in order to fully utilize the bandwidth resources. However, it has been reported that when the used routes' characteristics, i.e. available bandwidth and delay, are much different, R-M/TCP cannot achieve the desired throughput from the routes. This is because R-M/TCP originally transmits data packets in a round-robin manner through the routes. In this paper, therefore, we propose R-M/TCP using Packet Scheduling Algorithm (PSA). Instead of using the round-robin manner, R-M/TCP utilizes PSA that accounts for time-varying bandwidth and delay of each path so that number of data packets arriving in out-of-order at the receiver can be minimized and the desired throughput can be achieved. Quantitative simulations are conducted to show effectiveness of R-M/TCP using PSA.

Machine learning and data mining algorithms are increasingly being used in the intrusion detection systems (IDS), but their performances are laggard to some extent especially applied in network based intrusion detection: the larger load of network traffic monitoring requires more efficient algorithm in practice. In this paper, we propose and design an anomaly intrusion detection (AID) system based on the vector quantization (VQ) which is widely used for data compression and high-dimension multimedia data index. The design procedure optimizes the performance of intrusion detection by jointly accounting for accurate usage profile modeling by the VQ codebook and fast similarity measures between feature vectors to reduce the computational cost. The former is just the key of getting high detection rate and the later is the footstone of guaranteeing efficiency and real-time style of intrusion detection. Experiment comparisons to other related researches show that the performance of intrusion detection is improved greatly.

Security protocols flaws represent a substantial portion of security exposures of data networks. In order to evaluate security protocols against any attack, formal methods are equipped with a number of techniques. Unfortunately, formal methods are applicable for static state only, and don't guarantee detecting all possible flaws. Therefore, formal methods should be complemented with dynamic protection. Anomaly detection systems are very suitable for security protocols environments as dynamic activities protectors. This paper presents an intrusion detection system that uses a number of different anomaly detection techniques to detect attacks against security protocols.

Finding intracranial aneurysms plays a key role in preventing serious cerebral diseases such as subarachnoid hemorrhage. For detection of aneurysms, magnetic resonance angiography (MRA) can provide detailed images of arteries non-invasively. However, because over 100 MRA images per subject are required to cover the entire cerebrum, image diagnosis using MRA is very time-consuming and labor-intensive. This article presents a computer-aided diagnosis (CAD) system for finding aneurysms with MRA images. The principal components are identification of aneurysm candidates (= ROIs; regions of interest) from MRA images and estimation of a fuzzy degree for each aneurysm candidate based on a case-based reasoning (CBR). The fuzzy degree indicates whether a candidate is true aneurysm. Our system presents users with a limited number of ROIs that have been sorted in order of fuzzy degree. Thus, this system can decrease the time and the labor required for detecting aneurysms. Experimental results using phantoms indicate that the system can detect all aneurysms at branches of arteries and all saccular aneurysms produced by dilation of a straight artery in 1 direction perpendicular to the principal axis. In a clinical evaluation, performance in finding aneurysms and estimating the fuzzy degree was examined by applying the system to 16 subjects with a total of 19 aneurysms. The experimental results indicate that this CAD system detected all aneurysms except a fusiform aneurysm, and gave high fuzzy degrees and high priorities for the detected aneurysms.

To clarify the correspondence between Shielding Effectiveness (SE) of shielding materials and their physical property, we propose an equivalent circuit for a shielding effectiveness test apparatus using a dual TEM cell, and show its validity. By considering the structure of dual TEM cell that consists of a pair of cells coupled via an aperture in their common wall, we defined the capacitance C and mutual inductance M, that respectively express the electric coupling and magnetic coupling between two center conductors. By the measurement of unloaded S-parameter, we determined the values of C and M for a dual TEM cell in hand. Next, the shielding material was approximated by the apparent sheet resistivity Rs, and was used in the equivalent circuit of loaded aperture. As a result, the coupling level calculated from the equivalent circuit agreed well with the measured data in frequencies below 300 MHz.

The network performance of a single joint multicasting capable optical cross-connect (jMC-OXC) integrating both space- and frequency-splitters is simulated. The results show that the jMC-OXC architecture with limited frequency-splitters can obtain a close performance to that with full frequency splitters. The improvement offered by jMC-OXCs on the performance of multicasting routing is also discussed.

Based on the concept of Equivalent Transformation Method of Material Constant (ETMMC), a thin and light weight EM-wave absorber is newly proposed. It becomes possible to merge both the competing characteristics of changing the matching frequency toward a higher frequency region by means of punching out small holes in the magnetic absorber and of changing the matching frequency toward a lower frequency region by attaching periodical conductive patterns to the surface of it. First, the ETMMC idea is introduced in this paper. The detailed matching characteristics of the present absorber are investigated based on FDTD analysis. The matching mechanism is clarified from input admittance chart viewpoints. The matching characteristics can be changed from 2.4 GHz to above 6.0 GHz using carbonyl iron with the thickness of 2 mm and improved below -20 dB.

We propose a new security class, called plaintext simulatability, defined over the public-key encryption schemes. The notion of plaintext simulatability (denoted PS) is similar to the notion of plaintext awareness (denoted PA) defined in [3], but it is "properly" a weaker security class for public-key encryption. It is known that PA implies the class of CCA2-secure encryption (denoted IND-CCA2) but not vice versa. In most cases, PA is "unnecessarily" strong--In such cases, PA is only used to study that the public-key encryption scheme involved meets IND-CCA2, because it looks much easier to treat the membership of PA than to do "directly" the membership of IND-CCA2. We show that PS also implies IND-CCA2, while preserving such a technical advantage as well as PA. We present two novel CCA2-secure public-key encryption schemes, which should have been provided with more complicated security analyses. One is a random-oracle version of Dolev-Dwork-Naor's encryption scheme [8],[9]. Unlike the original scheme, this construction is efficient. The other is a public-key encryption scheme based on a strong pseudo-random permutation family [16] which provides the optimal ciphertext lengths for verifying the validity of ciphertexts, i.e., (ciphertext size) = (message size) + (randomness size). According to [19], such a construction remains open. Both schemes meet PS but not PA.

In this paper, we present a new class of public-key cryptosystem (PKC) using algebraic coding on the basis of superimposition and randomness. The proposed PKC is featured by a generator matrix, in a characteristic form, where the generator matrix of an algebraic code is repeatedly used along with the generator matrix of a random code, as sub-matrices. This generator matrix, in the characteristic form, will be referred to as K-matrix. We show that the K-matrix yields the following advantages compared with the conventional schemes: (i) It realizes an abundant supply of PKCs, yielding more secure PKCs, (ii) It realizes a short public key.

In this paper, we propose a construction method of three-dimensional deformable models that represent tree-shaped human organs, such as bronchial tubes, based on results obtained by statistically analyzing the distributions of bifurcation points in the tree-shaped organs. The models are made to be used as standard templates of tree-shaped organs in medical image recognition, and are formed by control points that can be uniquely identified as structural elements of organs such as bifurcation tracheae in bronchial tubes. They can be transfigured based on the statistical validity of relationships between the control points. The optimal state of that transfiguration is determined within the framework of energy minimization. Experimental results from bronchial tubes are shown on actual CT images.

This paper presents an improved gate drive circuit for high power GTO thyristors. The energy-storage/transfer characteristics of an air-core reactor and the fast switching characteristics of FET are employed to make a high gate current of sharp pulse form. The power loss in the gate drive circuit is reduced by using the low resistance and the hysteresis comparator to detect and control the steady on-gate current. The proposed gate drive circuit is analyzed and its usefulness is confirmed by experiments.

We present a depth video enhancement algorithm in order to provide high quality haptic interaction. As the telecommunication technology emerges rapidly, the depth image-based haptic interaction is becoming viable for broadcasting applications. Since a real depth map usually contains discrete and rugged noise, its haptic interaction produces the distorted force feedback. To resolve these problems, we propose a two-step refinement and adaptive sampling algorithm. In the first step, noise is removed by the median-filtering technique in 2D image space. Since not all pixels can be used to reconstruct the 3D mesh due to limited system resources, the filtered map is adaptively sampled based on the depth variation. Sampled 2D pixels, called feature points, are triangulated and projected onto 3D space. In the second refinement step, we apply the Gaussian smoothing technique to the reconstructed 3D surface. Finally, 3D surfaces are rendered to compute a smooth depth map from Z-buffer.

The adaptive Volterra filter (AVF) is attractive in adaptive filtering applications because its expansion is a linear combination of the input and output signals. However, the formidable computational work of AVF is prohibitive for practical applications. In this letter, we present a parallel fast recursive least squares (RLS) second-order adaptive Volterra filter (PAVF) to reduce computational load. Our discussion is based on the approach of the fast RLS AVF [3], by which the computational complexity has been reduced to O(N3) multiplications per time instant, where O(·) denotes "order of," and N is the filter length. Proposed PAVF consists of several subfilters partitioned from the conventional AVF, with parallel implementation, the computational work can be reduced effectively. Several simulation results are presented to validate the proposed method.