Kumiko NOMURA Satoshi TAYU Shuichi UENO
In this paper we show that an outerplanar graph G with maximum degree at most 3 has a 2-D orthogonal drawing with no bends if and only if G contains no triangles. We also show that an outerplanar graph G with maximum degree at most 6 has a 3-D orthogonal drawing with no bends if and only if G contains no triangles.
Shigeyuki SAKAZAWA Yasuhiro TAKISHIMA Yoshinori KITATSUJI Yasuyuki NAKAJIMA Masahiro WADA Kazuo HASHIMOTO
This paper presents a novel data transmission protocol "SVFTP," which enables high-speed and error-free video data transmission over IP networks. A video transmission system based on SVFTP is also presented. While conventional protocols are designed for file transmission, SVFTP focuses on video data as a continuous media. In order to fit a flexible video transmission system, SVFTP achieves higher throughput on the long distance link as well as transmission interruption/resumption and progressive download and play back. In addition, a rate shaping mechanism for SVFTP is introduced in order to control greediness and burst traffic of multiple-TCP sessions. Laboratory and field transmission experiments show that SVFTP achieves high performance and functionality.
Sineenard PINYAPONG Toshikazu KATO
Nowadays more people have started using their mobile phone to access information they need from anywhere at anytime. In advanced mobile technology, Location Service allows users to quickly pinpoint their location as well as makes a recommendation to fascinating events. However, users desire more appropriate recommendation services. In other words, the message service should push a message at a proper place in time. In consequence, customers obtain a higher level of satisfaction. In this paper, we propose a framework of time, place, purpose and personal profile based recommendation service. We illustrate scenarios in "push", "pull" and "don't disturb" services, where our DB queries can recommend the relevant message to users. The three factors: time, place and purpose are mutually dependent and the basic rules to analyze the essential data are summarized. We also create algorithms for DB query. We are filtering messages by one important factor: personal profile such as user's preference and degree of preference. Furthermore, we discuss an implementation of the prototype system, including results of experimental evaluation.
Broadening the frequency bandwidth of antennas has been one of the major subjects concerning antenna design technologies. Two of the major subjects for microstrip antennas, which appeared in the 1970s, have also been the broadening of the frequency bandwidth and the sharing of multifrequency bands. In this paper, we describe the broadband and multiband techniques of printed antennas, and show the configurations of realized broadband and multiband antennas and their characteristics. Here, resonant-type microstrip antennas, planar monopole antennas, fractal antennas and ultra-wideband printed antennas are introduced. The optimum design techniques using a genetic algorithm are introduced for developing broadband and multiband printed antennas. The usefulness of this method is verified by the simulation and experimental results of the fabricated planar monopole antenna which has ultrawide-band characteristics.
Younchan JUNG J. William ATWOOD
The playout delay for voice over IP applications is adjusted on every talkspurt. The parameter β that controls the delay/packet loss ratio is usually fixed, based on high jitter conditions. In this letter, a β-adaptive playout algorithm is presented, where the β is adjusted. The buffering delays and lateness rates are compared against the existing algorithm with the fixed β. We show that the β-adaptive system improves the lateness loss performance, especially for low jitter conditions, while maintaining almost identical buffering delay/lateness loss performance when jitter is high.
Jittima NITTAYAWAN Suwan RUNGGERATIGUL
Several regular topologies have been proposed to be used as the logical topology for WDM networks. These topologies are usually evaluated and compared based on the metrics related to network performance. It can be simply shown that this is generally not sufficient since better network performance can be achieved by increasing more network facilities. However, doing this eventually increases the network cost. Thus, the comparison of topologies must be performed by using an evaluation function that includes both the network performance metric and the network cost. In this paper, we propose a model to find the optimum regular logical topology for wavelength routed WDM networks. ShuffleNet, de Bruijn graph, hypercube, Manhattan Street Network, and GEMNet are the five well-known and commonly used regular topologies compared in this paper. By solving the two subproblems on node placement optimization, and routing and wavelength assignment, we obtain the evaluation function used in the topology comparison. Numerical results show that GEMNet is the optimum logical topology for the wavelength routed WDM networks, where it can take one of the three forms of ShuffleNet, de Bruijn graph, and its own configurations.
Satoru AKIYAMA Takao WATANABE Nobuhiro OODAIRA Tsuyoshi ISHIKAWA Digh HISAMOTO
To realize a high-density on-chip memory, the authors have proposed a novel logic-process-compatible memory cell. This cell consists of two logic transistors, and placing a planar MIM (metal insulator metal) capacitor on a copper wire above the transistors produces a memory area of 26 F2, which is approximately 60% smaller than a 6T SRAM cell. A suitable cell-bias design and a dual precharge scheme solve the coupling problem inherent in the cell and allow standard logic transistors to be used. This cell--applying the proposed schemes--can handle 10-ns cycle time at a bit-line voltage of 0.7 V. The random cycle is about three times faster than that of a conventional VBL precharge scheme. These results indicate that the umbrella cell is a strong candidate for providing a high-density memory for SOC applications.
The performance of en-route web caching mainly depends on where the caches are located and how the cache contents are managed. In this paper, we address the problem of proxy placement in en-route web caching for tree networks, i.e., computing the optimal locations for placing k web proxies in a network such that some specified objectives are achieved. Based on our proposed model, we formulate this problem as an optimization problem and compute the optimal locations using a computationally efficient dynamic programming-based algorithm. We also extend our solution for tree networks to solve the same problem for autonomous systems. Finally, we implement our algorithms and evaluate our model on several performance metrics through extensive simulation experiments. We also compare the performance of our model with the best available heuristic KMPC model, as well as the random proxy placement model. The implementation results show that our model outperforms all the other models with respect to all performance metrics considered. The average improvements of our model over the KMPC model and the random proxy placement model are about 31.9 percent and 58.6 percent in terms of all the performance metrics considered.
Jang Yeon KWON Do Young KIM Hans S. CHO Kyung Bae PARK Ji Sim JUNG Jong Man KIM Young Soo PARK Takashi NOGUCHI
Poly-Si TFT (Thin Film transistor) fabricated below 170 using excimer laser crystallization of sputtered Si films was characterized. In particular, a gate insulator with a breakdown field exceeding 8 MV/cm was deposited by using ICP (Inductively Coupled Plasma) CVD (Chemical Vapor Deposition). A buffer layer possessing high thermal conductivity was inserted between the active channel and the plastic substrate, in order to protect the plastic substrate from the thermal energy of the laser and to increase adhesion of Si film on plastic. Using this method, we successfully fabricate TFT with a stable electron field-effect mobility value greater than 14.7 cm2/Vsec.
A new hybrid method for characterizing the irregular power/ground plane pair is developed in this paper by combining the conventional eigen-mode expansion method with the new-presented inverted composition method and a simple model order reduction. By the approach, the eigen-mode expansion method can be extended to the characteristics research of the power/ground plane pair with holes. In this gridless method, ports and decoupling capacitors can be arbitrarily placed on the plane pair. The numerical example demonstrates its good validity.
Hideaki TAKADA Shiro SUYAMA Kenji NAKAZAWA
We are developing a simple three-dimensional (3-D) display method that uses only two transparent images using luminance division displays without any extra equipment. This method can be applied to not only electronic displays but also the printed sheets. The method utilizes a 3-D visual illusion in which two ordinary images with many edges can be perceived as an apparent 3-D image with continuous depth between the two image planes, when two identical images are overlapped from the midpoint of the observer's eyes and their optical-density ratio is changed according to the desired image depths. We can use transparent printed sheets or transparent liquid crystal displays to display two overlapping transparent images using this 3-D display method. Subjective test results show that the perceived depths changed continuously as the optical-density ratio changed. Deviations of the perceived depths from the average for each observer were sufficiently small. The depths perceived by all six observers coincided well.
Satoshi NAKAMURA Kazuya TAKEDA Kazumasa YAMAMOTO Takeshi YAMADA Shingo KUROIWA Norihide KITAOKA Takanobu NISHIURA Akira SASOU Mitsunori MIZUMACHI Chiyomi MIYAJIMA Masakiyo FUJIMOTO Toshiki ENDO
This paper introduces an evaluation framework for Japanese noisy speech recognition named AURORA-2J. Speech recognition systems must still be improved to be robust to noisy environments, but this improvement requires development of the standard evaluation corpus and assessment technologies. Recently, the Aurora 2, 3 and 4 corpora and their evaluation scenarios have had significant impact on noisy speech recognition research. The AURORA-2J is a Japanese connected digits corpus and its evaluation scripts are designed in the same way as Aurora 2 with the help of European Telecommunications Standards Institute (ETSI) AURORA group. This paper describes the data collection, baseline scripts, and its baseline performance. We also propose a new performance analysis method that considers differences in recognition performance among speakers. This method is based on the word accuracy per speaker, revealing the degree of the individual difference of the recognition performance. We also propose categorization of modifications, applied to the original HTK baseline system, which helps in comparing the systems and in recognizing technologies that improve the performance best within the same category.
Sang Gu KANG Doo Hyung WOO Hee Chul LEE
Transferring the image information in analog form between the focal plane array (FPA) and the external electronics causes the disturbance of the outside noise. On-chip analog-to-digital (A/D) converter into the readout integrated circuit (ROIC) can eliminate the possibilities of the cross-talk of noise. Also, the information can be transported more efficiently in power in the digital domain compared to the analog domain. In designing on-chip A/D converter for cooled type high density infrared detector array, the most stringent requirements are power dissipation, number of bits, die area and throughput. In this study, pipelined type A/D converter was adopted because it has high operation speed characteristics with medium power consumption. Capacitor averaging technique and digital error correction for high resolution was used to eliminate the error which is brought out from the device mismatch. The readout circuit was fabricated using 0.6 µm CMOS process for 128 128 mid-wavelength infrared (MWIR) HgCdTe detector array. Fabricated circuit used direct injection type for input stage, and then S/N ratio could be maximized with increasing the integration capacitor. The measured performance of the 14 b A/D converter exhibited 0.2 LSB differential non-linearity (DNL) and 4 LSB integral non-linearity (INL). A/D converter had a 1 MHz operation speed with 75 mW power dissipation at 5 V. It took the die area of 5.6 mm2. It showed the good performance that can apply for cooled type high density infrared detector array.
Gweon-Do JO Min-Joung SHEEN Seung-Hwan LEE Kyoung-Rok CHO
As the code division multiple access (CDMA) based third generation cellular infrastructure requires high performance signal processing in a baseband modem, an application-specific integrated circuit or a field-programmable gate array has commonly been used for chip rate processing. In this paper, the use of digital signal processors (DSP) is explored for a cdma2000 and a wideband CDMA channel modem with the goal of increasing flexibility. The design concepts of the prototype software-defined radio platform we implemented to estimate the potential and feasibility of commercial SDR platforms are presented. We discuss the hardware and software architecture of the platform, considerations for reconfigurability, and the test results. We also address practical issues for real-time chip rate processing and optimization schemes of DSP software, and provide detailed measurement results of DSP performance.
Bandpass sampling algorithm is effectively adopted to obtain the digital signal with significantly reduced sampling rate for a single radio frequency(RF) signal. In order to apply the concept to multiple RF signals, we propose bandpass sampling algorithms with the normal and the inverse placements since we are interested in uniform order of the spectrum in digital domain after bandpass sampling. In addition, we verify the propose algorithms with generalized equation forms for the multiple RF signals.
We consider the edge-linking approach for accurate locating of moving object boundaries in video segmentation. We review the existing methods and propose a scheme designed for efficiency and better accuracy. The scheme first obtains a very rough outline of an object by a suitable means, e.g., change detection. It then forms a relatively compact image region that properly contains the object, through a procedure termed "mask sketch." Finally, the outermost edges in the region are found and linked via a shortest-path algorithm. Experiments show that the scheme yields good performance.
Jianqing WANG Tetsuji TSUCHIKAWA Osamu FUJIWARA
The use of metal-coated plastics is increasing as shielding materials of electronic and information products due to their lightweight. In this paper, a finite-difference time-domain (FDTD) algorithm, based on the derivation of a time-domain representation of the surface impedance of an equivalent resistive film, was developed to analyze the electromagnetic penetration of pulsed electromagnetic fields through metal-coated plastics. The validity of the proposed algorithm, in both the far-field and near-field cases, was verified by comparing the calculated penetrated electromagnetic fields or shielding effectiveness with theoretical and measured ones. Good agreement between them demonstrated the usefulness of the FDTD algorithm.
Shinichiro OHNUKI Takashi HINATA
Transient scattering from parallel plate waveguide cavities is studied by using the combination of a point matching technique and numerical inversion of Laplace transform. We thoroughly investigate the scattering mechanism for a half-sine pulse and modulated-sine pulse incidence. The advantages and disadvantages on the target recognition are clarified in terms of the internal objects, incident waveforms, and polarizations.
Md. Saidur RAHMAN Noritsugu EGI Takao NISHIZEKI
A plane graph is a planar graph with a fixed embedding. In a no-bend orthogonal drawing of a plane graph, each vertex is drawn as a point and each edge is drawn as a single horizontal or vertical line segment. A planar graph is said to have a no-bend orthogonal drawing if at least one of its plane embeddings has a no-bend orthogonal drawing. In this paper we consider a class of planar graphs, called subdivisions of planar triconnected cubic graphs, and give a linear-time algorithm to examine whether such a planar graph G has a no-bend orthogonal drawing and to find one if G has.
Ippei SHAKE Hidehiko TAKARA Ikuo OGAWA Tsutomu KITOH Minoru OKAMOTO Katsuaki MAGARI Takuya OHARA Satoki KAWANISHI
This paper presents 160-Gbit/s full channel time-division demultiplexing using a semiconductor optical amplifier hybrid integrated demultiplexer on a planer lightwave circuit. Error-free demultiplexing from a 160-Gbit/s signal to 8 channel 20 Gbit/s signals is successfully demonstrated. Results of a 160-Gbit/s optical time-division-multiplexed full channel OTDM signal transmission experiment using the circuit and successful 80-km transmission are presented.