Yasuharu MIZUTANI Fumihiko INO Kenichi HAGIHARA
This paper describes the design and implementation of a testbed for predicting master/slave (M/S) programs written using Message Passing Interface (MPI) programs. The testbed, named M/S Emulator (MSE), aims at assisting developers in evaluating the performance of M/S programs and dynamic load-balancing strategies on clusters of PCs. In order to realize this, MSE predicts the communication time by using a realistic parallel computational model, an extension of the LogGPS model. This extended model improves the prediction accuracy on a large number of processors, because it captures the master's bottleneck: the overhead required for retrieving arrival messages from the slaves. Current MSE also employs a best effort emulation method for predicting the calculation time. In our experiments, MSE demonstrated an accurate prediction on clusters, especially on a larger number of nodes. Therefore, we believe that our extended model enables us to analyze the scalability of the M/S program performance.
Zonghuang YANG Yoshifumi NISHIO Akio USHIDA
The paper discusses the spatio-temporal phenomena in autonomous two-layer Cellular Neural Networks (CNNs) with mutually coupled templates between two layers. By computer calculations, we show how pattern formations, autowaves and classical waves can be regenerated in the networks, and describe the properties of these phenomena in detail. In particular, we focus our discussion on the necessary conditions for generating these spatio-temporal phenomena. In addition, the influences of the template parameters and initial state conditions of CNNs on the spatio-temporal phenomena are investigated.
Masayuki KUROSAKI Hitoshi KIYA
A scheme of error correction for JPEG2000 codestream is proposed in this paper. The scheme uses a forward error correction code (FEC) and a data hiding technique. The headers and the higher quality layers of the codestream are coded using FEC codes. Then the parity data are separated from the FEC-coded data and hidden in the JPEG2000 codestream. The hidden data are used for error correction at the decoder. Several error correction codes with different strength are selected for the main header, the tile-part headers, the packet headers, and the bodies. The codestream generated by the proposed scheme has backward compatibility with a standard JPEG2000 codestream. Thus, it can be decoded with a general decoder. Simulation results demonstrated the effectiveness of the proposed scheme.
Akihiko HIGUCHI Kazutoshi KOBAYASHI Hidetoshi ONODERA
This paper proposes an instruction-level power estimation method for an embedded RISC processor, the power consumption of which fluctuates so much by applications and input data. The proposed method estimates the power consumption from the result of ISS (Instruction Set Simulator) and energy tables according to Hamming Distance of Registers (HDR) of all instructions. It is over 105 times faster than the gate-level detailed logic simulation, while the estimated power curves have the same tendency with those from the logic simulation. The proposed method realizes both accurate and fast power estimation of embedded processors.
In this paper, we introduce the following m-layered hard constrained convex feasibility problem HCF(m): Find a point u m, where 0:=H (a real Hilbert space), i: = arg min gi(i-1) and gi(u):=wi,jd 2(u,Ci,j) are defined for (i) nonempty closed convex sets Ci,jH and (ii) weights wi,j > 0 satisfying wi,j=1 (i {1,,m}, j {1,,Mi}. This problem is regarded as a natural extension of the standard convex feasibility problem: find a point u Ci, where Ci H (i {1,, M}) are closed convex sets. Unlike the standard problem, HCF(m) can handle the inconsistent case; i.e., i,j Ci,j = , which unfortunately arises in many signal processing, estimation and design problems. As an application of the hybrid steepest descent method for the asymptotically shrinking nonexpansive mapping, we present an algorithm, based on the use of the metric projections onto Ci,j, which generates a sequence (un) satisfying limn d(un,3) = 0 (for M1 = 1) when at least one of C1,1 or C2,j's is bounded and H is finite dimensional. An application of the proposed algorithm to the pulse shaping problem is given to demonstrate the great flexibility of the method.
Shih-Hsuan YANG Chun-Yen LIAO Chin-Yun HSIEH
Although watermarking techniques have been extensively developed for natural videos, little progress is made in the area of graphics animation. Following the former successful MPEG-1 and MPEG-2 coding standards that provide efficient representations of natural videos, the emerging MPEG-4 standard incorporates new coding tools for 2D mesh animation. Graphics animation information is crucial for many applications and may need proper protection. In this paper, we develop a watermarking technique suitable for MPEG-4 2D mesh animation. The proposed method is based on the multiresolution analysis of 2D dynamic mesh. We perform wavelet transform on the temporal sequence of the node points to extract the significant spectral components of mesh movement, which we term the "feature motions. " A binary watermark invisibly resides in the feature motions based on the spread-spectrum principle. Before watermark detection, a spatial-domain least-squares registration technique is used to restore the possibly geometrically distorted mesh data. Each watermark bit is then detected by hard decision with cryptographically secure keys. We have tested the proposed method with a variety of attacks, including affine transformations, temporal smoothing, spectral enhancement and attenuation, additive random noise, and a combination of the above. Experimental results show that the proposed watermarks can withstand the aforementioned attacks.
Behrouz Homayoun FAR Wei WU Mohsen AFSHARCHI
Software agents are knowledgeable, autonomous, situated and interactive software entities. Agents' interactions are of special importance when a group of agents interact with each other to solve a problem that is beyond the capability and knowledge of each individual. Efficiency, performance and overall quality of the multi-agent applications depend mainly on how the agents interact with each other effectively. In this paper, we suggest an agent model by which we can clearly distinguish different agent's interaction scenarios. The model has five attributes: goal, control, interface, identity and knowledge base. Using the model, we analyze and describe possible scenarios; devise the appropriate reasoning and decision making techniques for each scenario; and build a library of reasoning and decision making modules that can be used readily in the design and implementation of multiagent systems.
In this paper, we present a novel energy compaction method, called the selective block-wise reordering, which is used with SPIHT (SBR-SPIHT) coding for low rate video coding to enhance the coding efficiency for motion-compensated residuals. In the proposed coding system, the motion estimation and motion compensation schemes of H.263 are used to reduce the temporal redundancy. The residuals are then wavelet transformed. The block-mapping reorganization utilizes the wavelet zerotree relationship that jointly presents the wavelet coefficients from the lowest subband to high frequency subbands at the same spatial location, and allocates each wavelet tree with all descendents to form a wavelet block. The selective multi-layer block-wise reordering technique is then applied to those wavelet blocks that have energy higher than a threshold to enhance the energy compaction by rearranging the significant pixels in a block to the upper left corner based on the magnitude of energy. An improved SPIHT coding is then applied to each wavelet block, either re-ordered or not. The high energy compaction resulting from the block reordering can reduce the number of redundant bits in the sorting pass and improve the quantization efficiency in the refinement pass of SPIHT coding. Simulation results demonstrate that SBR-SPIHT outperforms H.263 by 1.28-0.69 dB on average for various video sequences at very low bit-rates, ranging from 48 to 10 kbps.
Online shopping is becoming more and more popular in recent years. However, users are still unable to find what they want on the online market very efficiently. In our previous paper we suggested a system that helps to find short-sleeved T-shirts for young women on the online market. Then we conducted several verification experiments and proved that the system was effective. In this paper, we modified the system by adopting the following schemes in order to make it more versatile; First, all information is presented in a unified format. Second, users are provided with multiple-choice key words. Third, users search results are used to select information that is truly useful for the user. Lastly, we conducted several verification experiments and proved that these schemes were effective.
Giedre SABALIAUSKAITE Shinji KUSUMOTO Katsuro INOUE
For more than twenty-five years software inspections have been considered an effective method for defect detection. Inspections have been investigated through controlled experiments in university environment and industry case studies. However, in most cases software inspections have been used for defect detection in documents of conventional structured development process. Therefore, there is a significant lack of information about how inspections should be applied to Object-Oriented artifacts, such as Object-Oriented code and design diagrams. In addition, extensive work is needed to determine whether some inspection techniques can be more beneficial than others. Most inspection experiments include inspection meetings after individual inspection is completed. However, several researchers suggested that inspection meetings may not be necessary since an insignificant number of new defects are found as a result of inspection meeting. Moreover, inspection meetings have been found to suffer from process loss. This paper presents the findings of a controlled experiment that was conducted to investigate the performance of individual inspectors as well as 3-person teams in Object-Oriented design document inspection. Documents were written using the notation of Unified Modelling Language. Two reading techniques, namely Checklist-based reading (CBR) and Perspective-based reading (PBR), were used during experiment. We found that both techniques are similar with respect to defect detection effectiveness during individual inspection as well as during inspection meetings. Investigating the usefulness of inspection meetings, we found out that the teams that used CBR technique exhibited significantly smaller meeting gains (number of new defect first found during team meeting) than meeting losses (number of defects first identified by an individual but never included into defect list by a team); meanwhile the meeting gains were similar to meeting losses of the teams that used PBR technique. Consequently, CBR 3-person team meetings turned out to be less beneficial than PBR 3-person team meetings.
Jian-Qing LI Hong-Shik PARK Hyeong-Ho LEE
A new partitioning configuration that divides a given network into overlapped protection areas is investigated. If two working sub-paths are in the adjacent different working areas, their corresponding protection sub-paths can share a wavelength on the link that belongs to the overlap between two adjacent protection areas. The objective of overlapping is to increase sharing of the protection sub-paths that belong to the adjacent protection areas. The performances of resource utilization and recovery time are improved without any significant degradation of other performances.
Mitsuji MUNEYASU Yumi WAKASUGI Ken'ichi KAGAWA Kensaku FUJII Takao HINAMOTO
A multiple channel active noise control (ANC) system with several secondary sources, error sensors, and reference sensors has been used for complicated noise fields. Centralized multiple channel ANC systems have been proposed, however implementation of such systems becomes difficult according to increase of control points. Distributed multiple channel ANC systems which have more than a controller are considered. This paper proposes a new implementation of distributed multiple channel ANC systems based on simultaneous equations methods. In the proposed algorithm, communications between controllers are permitted to distribute the computational burden and to improve the performance of noise reduction. This algorithm shows good performances for noise cancellation and tracking of changes in the error paths.
Yasuyuki SUGAYA Kenichi KANATANI
Feature point tracking over a video sequence fails when the points go out of the field of view or behind other objects. In this paper, we extend such interrupted tracking by imposing the constraint that under the affine camera model all feature trajectories should be in an affine space. Our method consists of iterations for optimally extending the trajectories and for optimally estimating the affine space, coupled with an outlier removal process. Using real video images, we demonstrate that our method can restore a sufficient number of trajectories for detailed 3-D reconstruction.
The paper presents a novel stroke decomposition approach based on a directional filtering technique for recognizing Chinese characters. The proposed filtering technique uses a set of the second-order Gaussian derivative (SOGD) filters to decompose a character into a number of stroke segments. Moreover, a new Gaussian function is proposed to overcome the general limitation in extracting stroke segments along some fixed and given orientations. The Gaussian function is designed to model the relationship between the orientation and power response of the stroke segment in the filter output. Then, an optimal orientation of the stroke segment can be estimated by finding the maximal power response of the stroke segment. Finally, the effects of decomposition process are analyzed using some simple structural and statistical features extracted from the stroke segments. Experimental results indicate that the proposed SOGD filtering-based approach is very efficient to decompose noisy and degraded character images into a number of stroke segments along an arbitrary orientation. Furthermore, the recognition performance from the application of decomposition process can be improved about 17.31% in test character set.
Takashi KURAFUJI Yasunobu NAKASE Hidehiro TAKATA Yukinaga IMAMURA Rei AKIYAMA Tadao YAMANAKA Atsushi IWABU Shutarou YASUDA Toshitsugu MIWA Yasuhiro NUNOMURA Niichi ITOH Tetsuya KAGEMOTO Nobuharu YOSHIOKA Takeshi SHIBAGAKI Hiroyuki KONDO Masayuki KOYAMA Takahiko ARAKAWA Shuhei IWADE
We apply a selective-sets resizable cache and a complete hierarchy SRAM for the high-performance and low-power RISC CPU core. The selective-sets resizable cache can change the cache memory size by varying the number of cache sets. It reduces the leakage current by 23% with slight degradation of the worst case operating speed from 213 MHz to 210 MHz. The complete hierarchy SRAM enables the partial swing operation not only in the bit lines, but also in the global signal lines. It reduces the current consumption of the memory by 4.6%, and attains the high-speed access of 1.4 ns in the typical case.
Tohru KONDO Kouji NISHIMURA Reiji AIBARA
FEC (Forward Error Correction) can repair the damage to communication quality due to packet loss. The growing requirement of FEC for high-quality video transmission is inevitable on broadband networks. We have designed and implemented FEC, and integrated it to our developed video transmission system named "mpeg2ts." Our goal is to make it possible to deploy this system on the broadband Internet. However, the problem with constant redundancy of FEC is that weakness to fluctuation of network condition. To resolve this problem, in this paper, we propose and evaluate an efficient FEC method for high-quality video transmission. The proposed mechanisms can provide robustness as well as saving of processing load and optimization of bandwidth consumption. Moreover, we integrate it into a system to deploy it on the real broadband Internet. Transmission experiment demonstrates availability of developed system deployed on the network.
Jun ZHANG JeoungChill SHIM Hiroyuki KURINO Mitsumasa KOYANAGI
The IP routing lookup problem is equivalent to finding the longest prefix of a packet's destination address in a routing table. It is a challenging problem to design a high performance IP routing lookup architecture, because of increasing traffic, higher link speed, frequent updates and increasing routing table size. At first, increasing traffic and higher link speed require that the IP routing can be executed at wire speed. Secondly, frequent routing table updates require that the insertion and deletion operations should be simple and low delay. At last, increasing routing table size hopes that less memory is used in order to reduce cost. Although many schemes to achieve fast lookup exist, less attention is paid on the latter two factors. This paper proposed a novel pipelined IP routing lookup architecture using selective binary search on hash table organized by prefix lengths. The evaluation results show that it can perform IP lookup operations at a maximum rate of one lookup per cycle. The hash operation ratio for one lookup can be reduced to about 1%, less than two hash operations are needed for one table update and only 512 kbytes SRAM is needed for a routing table with about 43000 prefixes. It proves to have higher performance than the existing schemes.
Sung Won YOON Hai Kwang LEE Jeong Hoon KIM Myoung Ho LEE
Image segmentation is an essential technique of image analysis. In spite of the issues in contour initialization and boundary concavities, active contour models (snakes) are popular and successful methods for segmentation. In this paper, we present a new active contour model, Gaussian Gradient Force snake (GGF snake), for segmentation of an endoscopic image. The GGF snake is less sensitive to contour initialization and it ensures a high accuracy, large capture range, and fast CPU time for computing an external force. It was observed that the GGF snake produced more reasonable results in various image types : simple synthetic images, commercial digital camera images, and endoscopic images, than previous snakes did.
Hiroyuki MICHINISHI Tokumi YOKOHIRA Takuji OKAMOTO Toshifumi KOBAYASHI Tsutomu HONDO
This paper proposes a new supply current test method for detecting floating gate defects in CMOS ICs. In the method, unusual increase of the supply current caused by defects is promoted by superposing an AC component on the DC power supply. Feasibility of the test is examined by some experiments on four DUTs with an intentionally caused defect. The results showed that our method could detect clearly all the defects, one of which may be detected by neither any functional logic test nor any conventional supply current test.
Normally, flow field is described with governing equations, such as the Navier-Stokes equations. However, for complex flow including multiphase and reactive flow such as combustion, this approach may not be suitable. As an alternative approach, Lattice Gas Automata (LGA) has been used to simulate fluid with mesoscopic particles by assuming that space and time are discrete, and the physical quantities take only a finite set of values. In this study, the model for combustion simulation is proposed, with the reaction probability depending on the local temperature to simplify the chemical reaction. Here, counter-flow twin flames are simulated. In order to validate this approach, some results of non-reactive flow are presented, compared with those by solving Navier-Stokes equations.