bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of taurine in diabetes and the development of diabetic complications
Authors: Hansen Svend Høime
Published: August 2002

The ubiquitously found β‐amino acid taurine has several physiological functions, e.g. in bile acid formation, as an osmolyte by cell volume regulation, in the heart, in the retina, in the formation ofN‐chlorotaurine by reaction with hypochlorous acid in leucocytes, and possibly for intracellular scavenging of carbonyl groups. Some animals, such as the cat and the C57BL/6 mouse, have disturbances in taurine homeostasis. The C57BL/6 mouse strain is widely used in diabetic and atherosclerotic animal models. In diabetes, the high extracellular levels of glucose disturb the cellular osmoregulation and sorbitol is formed intracellularly due to the intracellular polyol pathway, which is suspected to be one of the key processes in the development of diabetic late complications and associated cellular dysfunctions. Intracellular accumulation of sorbitol is most likely to cause depletion of other intracellular compounds including osmolytes such asmyo‐inositol and taurine. When considering the clinical complications in diabetes, several links can be established between altered taurine metabolism and the development of cellular dysfunctions in diabetes which cause the clinical complications observed in diabetes, e.g. retinopathy, neuropathy, nephropathy, cardiomyopathy, platelet aggregation, endothelial dysfunction and atherosclerosis. Possible therapeutic perspectives could be a supplementation with taurine and other osmolytes and low‐molecular compounds, perhaps in a combinational therapy with aldose reductase inhibitors. Copyright © 2001 John Wiley & Sons, Ltd.
Islet autoantibodies in cord blood: maternal, fetal, or neither?
Authors: Rewers Marian
Published: August 2002

In high‐risk type 1 diabetes populations, up to 3% of the general population newborns may express islet autoantibodies in cord blood and the vast majority of those appear to be maternal autoantibodies that disappear usually before the age of 9 months. Despite recent progress in standardization of autoantibody assays, some of the findings appear to be artifacts or non‐IgG‐mediated binding phenomena. It remains unclear whether transplacentally transmitted maternal autoantibodies play any role in protecting the offspring of diabetic women from diabetes. The evidence for fetal production of islet autoantibodies is very limited and remains to be validated in large prospective studies currently underway. Copyright © 2002 John Wiley & Sons, Ltd.
Thyroid hormone regulation of a transcriptional coactivator in Xenopus laevis: Implication for a role in postembryonic tissue remodeling
Authors: Amano Tosikazu , Leu Kimberly , Yoshizato Katsutoshi , Shi Yun‐Bo
Published: August 2002

Thyroid hormone (TH) affects biological processes by regulating gene transcription through TH receptors (TRs). In the presence of TH, TR activates target gene transcription by recruiting one or more transcription coactivators belonging to diverse groups. Here, we demonstrate that during TH‐dependent anuran metamorphosis, one such coactivator gene, the Xenopus laevis homolog of human Trip7, is up‐regulated by TH. Kinetic studies suggest that Xenopus Trip7 is most likely induced indirectly by TH in a tissue‐dependent manner. In the intestine, which undergoes extensive remodeling as the animal changes from being herbivorous to carnivorous, Trip7 is expressed at high levels during but not before or after metamorphosis. It is also up‐regulated in other growing or remodeling tissues such as the brain and limb but not in degenerating tadpole tail skin. By using frog oocyte as a model, we show that Trip7 influences basal transcription in a chromatin structure‐dependent manner but enhances the function of liganded TR regardless of the chromatin structure of the target promoter. In vitro studies indicate that Trip7 interacts directly with TR. These results suggest that during Xenopus metamorphosis, TH up‐regulates, albeit indirectly, Trip7 to enhance TR function during larval‐to‐adult tissue transformation. © 2002 Wiley‐Liss, Inc.
Mouse dystrophin enhancer preferentially targets lacZ expression in skeletal and cardiac muscle
Authors: Marshall Philip , Chartrand Nathalie , De Repentigny Yves , Kothary Rashmi , Pelletier Louise , Mueller Rudi , Worton Ronald G.
Published: August 2002

Duchenne muscular dystrophy is a muscle wasting disease that results from a dystrophin deficiency in skeletal and cardiac muscle. Studies concerning the regulatory elements that govern dystrophin gene expression in skeletal and/or cardiac muscle in both mouse and human have identified a promoter and an enhancer located in intron 1. In transgenic mice, the muscle promoter alone targets the expression of a lacZ reporter gene only to the right ventricle of the heart, suggesting the need for other regulatory elements to target skeletal muscle and the rest of the heart. Here we report that the mouse dystrophin enhancer from intron 1 can target the expression of a lacZ reporter gene in skeletal muscle as well as in other heart compartments of transgenic mice. Our results also suggest that sequences surrounding the mouse dystrophin enhancer may affect its function throughout mouse development. © 2002 Wiley‐Liss, Inc.
Gradients and forward spreading of vertebrate Hox gene expression detected by using a Hox/lacZ transgene
Authors: Gaunt Stephen J.
Published: August 2002

Elucidation of the kinetics with which vertebrate Hox expression patterns develop may help us to choose between various models already proposed to explain this process. The chick Hoxa‐7/lacZ transgene, expressed in mouse embryos, changes over time in the distribution of its activity along the developing posterior to anterior axis. During an establishment (E) phase (lasting at least up to 10 days) expression is graded from highest levels posteriorly, to low levels anteriorly. Within the graded domain, the overall level of expression spreads forward with time along both neurectoderm and paraxial mesoderm. Spreading in expression is not due to movement of cells, but to increases in both the proportion of lacZ expressing cells and the intensity of expression per cell. By 10.8 days, embryos have reached a late (L) phase in which an anterior up‐regulation in expression, together with a posterior down‐regulation, cause the graded nature of the expression to be lost. E and L phases are also seen for Hox gene expression detected by in situ hybridization. The switch from E to L occurs at progressively later times as we move 3′ to 5′ along the Hox cluster. The results are in keeping with models in which Hox genes become differentially expressed according to a graded concentration of an inducer. Binding motifs for the caudal (cdx) proteins, already proposed as such inducers, are conserved in mouse and chick Hoxa‐7 enhancer elements. © 2001 Wiley‐Liss, Inc.
An SNF2 factor involved in mammalian development and cellular proliferation
Authors: Raabe Eric H. , Abdurrahman Luby , Behbehani Greg , Arceci Robert J.
Published: August 2002

Members of the SNF2 (Sucrose Non‐Fermenter) family of chromatin‐remodeling proteins function in processes ranging from DNA repair to transcription to methylation. Using differential display, we recently identified a novel member of the SNF2 family that is highly expressed at the mRNA level in proliferating cells and is down‐regulated during apoptosis. We have named this gene PASG (Proliferation‐Associated SNF2‐like Gene). Northern blot analysis of adult mouse tissues shows PASG to be highly expressed in proliferating organs such as thymus, bone marrow, and testis and absent from nonproliferative tissues such as brain and heart. In situ hybridization analysis of mouse embryos shows that PASG is differentially expressed during development, with highest expression in developing face, limbs, skeletal muscle, heart, and tail. In vitro, PASG expression correlates with a shift from a quiescent to a proliferative state. Mice null for PASG (also known as LSH or Hells) are reported to die perinatally, although the mechanism for lethality is unclear (Geiman and Muegge, 2000). To test the hypothesis that PASG functions in cell proliferation, we compared 5‐bromodeoxyuridine (BrdU) incorporation in C33A cells transiently transfected with PASG versus empty vector and found that PASG transfected cells showed a significant decrease in the amount of BrdU incorporation. These findings suggest that PASG plays a role in cell proliferation and may function in the development of multiple cell lineages during murine embryogenesis. © 2001 Wiley‐Liss, Inc.
Smoothelin expression during chicken embryogenesis: Detection of an embryonic isoform
Authors: Deruiter Marco C. , Rensen Sanders S.M. , Coolen Gisela P.G.M. , Hierck Beerend P. , Bergwerff Maarten , Debie Wiel M.H. , Gittenberger‐De Groot Adriana C. , Van Eys Guillaume J.J.M.
Published: August 2002

Two isoforms of a novel smooth muscle cell (SMC) ‐specific cytoskeletal protein, smoothelin, have been described. In the adult chick, the 55‐kDa smoothelin‐A is expressed in visceral SMC, whereas the 120‐kDa smoothelin‐B is the major product in vascular SMC. Chicken was chosen to study smoothelin expression during embryogenesis and neonatally. Smoothelin‐B was found in vascular SMC from stage 20 onward. In visceral SMC, smoothelin‐B was present from stage 29 until hatching. Perinatally, a strong up‐regulation of smoothelin synthesis was observed in visceral tissues, coinciding with a switch to the A‐isoform. Transient smoothelin synthesis was observed in the somites and the developing heart. Western blotting revealed in these tissues a 62‐kDa smoothelin isoform, designated smoothelin‐C. Expression of the smoothelin isoforms seems to be strictly controlled with respect to cell type and developmental stage and may be related to the mode of contraction of the different cells. © 2001 Wiley‐Liss, Inc.
The Dyslexia Ecosystem
Authors: Nicolson Roderick I.
Published: August 2002

It is all too easy, in everyday interactions in dyslexia, to see the interactions in a semi‐adversarial fashion—parents competing to get more support for children, researchers competing to get more support for their theories, schools trying to get more money for their programmes. Such a set of analyses may be described as ‘zero‐sum’. If one party gains, the other one loses. If, by contrast, one views the dyslexia community as a complex, inter‐dependent ‘ecosystem’, a much more positive view emerges. It becomes clear that there are solutions for the system as a whole that are in a sense optimal for the system as a whole, solutions that are ‘win–win’, that is, all parties gain and none lose. In this article I develop this concept of the ‘dyslexia ecosystem’, and outline targets that would lead to progress for the ecosystem as a whole. Copyright © 2002 John Wiley & Sons, Ltd.
Development of the body checking questionnaire: A self‐report measure of body checking behaviors
Authors: Reas Deborah L. , Whisenhunt Brooke L , Netemeyer Rick , Williamson Donald A.
Published: August 2002

Objective

The purpose of this study was to develop a brief self‐report inventory to assess body checking behaviors.

Method

Using exploratory and confirmatory factor analyses, the 23‐item Body Checking Questionnaire (BCQ) was developed. The BCQ measures the global construct of body checking behaviors with three correlated subfactors that assess checking related to overall appearance, checking of specific body parts, and idiosyncratic checking rituals.

Results

The BCQ was found to have good test‐retest reliability (.94) and the subfactors had good internal consistency (.88, .92, and .83). The measure correlated highly with other measures of negative body image and eating disorders, demonstrating its concurrent validity. Additionally, the BCQ was found to differentiate normal controls and eating disorder patients, as well as nonclinical participants scoring high and low on a measure of concern with body size and dieting.

Discussion

Due to the potential role of ritualistic body checking in the maintenance of body dissatisfaction by directing excessive attention to body shape/weight, the BCQ may prove to be a useful clinical tool in the assessment and treatment of eating disorder patients. © 2002 by Wiley Periodicals, Inc. Int J Eat Disord 31: 324–333, 2002; DOI 10.1002/eat.10012
Imagery rescripting within cognitive behavior therapy for bulimia nervosa: An illustrative case report
Authors: Ohanian Vartouhi
Published: August 2002

Objective

This case report describes the use of imagery rescripting as an adjunct to cognitive behavior therapy (CBT) for bulimia nervosa.

Methods

The patient was a 22‐year‐old woman, who had a 6‐year history of diagnosable eating problems, with no comorbid diagnosis. She had a history of emotional abuse by her family. The single session of imagery rescripting was aimed at effecting change in the core beliefs that were hypothesized to result from that emotional abuse, and hence in the associated bulimic psychopathology.

Results

While eight sessions of conventional CBT reduced symptom behaviors by 50%, one session of imagery rescripting led to an almost complete cessation of the remaining binge‐purge behaviors. This effect was maintained at 14 weeks post‐imagery.

Conclusions

Imagery rescripting appears to be a valuable adjunct to conventional CBT in working with cases where there is an early history of trauma. Implications for treatment of eating disorders using this technique are considered, and relevant research designs are discussed. © 2002 by Wiley Periodicals, Inc. Int J Eat Disord xx:352–357, 2002. DOI 10.1002/eat.10044
Performance improving in skew‐coordinates DCT method for images by entropy coding based on Gaussian mixture distribution model
Authors: Yamane Nobumoto , Morikawa Yoshitaka , Nariai Takeshi
Published: August 2002

In the skew‐coordinates DCT coding method, an image is partitioned along the edge into variably shaped blocks and coded using the skew‐coordinates DCT adopted to the edge direction. Compared with the conventional square block DCT, it is known that the skew‐coordinates DCT can improve power packing efficiency and can reduce mosquito noise in the reconstructed image. In this paper, the entropy coding method of the skew‐coordinates DCT is studied in order to improve the compression ratio. As an entropy coding method, we adopt an adaptive code allocation method based on the Gaussian mixture distribution model and study the construction of the mixture model. Statistical characteristics of the DCT coefficients in real images are investigated and it is shown that the warping effect of the skew‐coordinates DCT can reduce the local variation of the variance distribution of the DCT coefficients and that, consequently, a simple mean‐power model is suitable as the mixture model. Finally, the result of a computer simulation experiment shows that the proposed method is useful in improving coding performance. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 84(7): 37–44, 2001
Time sidelobe reduction technique for binary phase coded pulse compression
Authors: Sato Reiji , Shinriki Masanori
Published: August 2002

A time sidelobe (TSL) reduction technique in binary code pulse compression is proposed. A code with a small peak sidelobe (PSL) is searched. Many codes have been obtained that have much smaller PSL than the conventional binary code with the compression ratio in the range from 5 to 16. Simulations are carried out for some of these codes and the optimum IF filter bandwidth is evaluated. It is confirmed that the waveform is stable for Doppler and the PSL value is kept small. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 84(12): 52–60, 2001
A new technique for measuring dispersion of optical fibers using a frequency‐shifted feedback fiber laser. part I: Measurement of group velocity dispersion
Authors: Yoshida Masato , Miyamoto Toshiyuki , Nakamura Koichiro , Ito Hiromasa
Published: August 2002

With the continually improving performance of long‐distance optical communication systems, it becomes important to administer and control wavelength dispersion of the optical fiber. In this paper, a method of measurement of the group velocity dispersion (GVD) of an optical fiber using optical frequency domain reflectometry is proposed. In this scheme, frequency‐chirped light is used as a light source and the total dispersion of the GVD of the optical fiber is measured from the variations of the optical frequency chirp rate after transmission through the fiber. In this method, the GVD value versus the optical wavelength can be measured directly. Another characteristic is that the effect of measurement error due to fluctuations of the fiber under test can be neglected. An experimental verification of the present scheme was performed with a frequency‐shifted feedback laser, which is an ideal linear chirped light source. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 85(2): 1–7, 2002
An 80 Gb/s optical I/O interface ATM switch MCM
Authors: Kawano Ryusuke , Yamanaka Naoaki , Oki Eiji , Okazaki Katsuhiko , Ohki Akira
Published: August 2002

For extensive proliferation of multimedia communications, high‐speed, large‐capacity node systems are required in addition to the technologies for transmission and access systems. Although the performance of the node system has progressed along with the technical advances of LSI, the LSI interconnection is now a bottleneck due to rapid advances in technology, and consequently this bottleneck may limit the performance of the node system. One way to resolve this situation and extract the performance of the LSI at the maximum is the multichip module (MCM) technology. Using this technology, high‐speed, multiply parallel signal transmission can be realized within MCM. However, the input and output of the signal to this MCM still suffers from bottlenecks in terms of connection distance, cable physical volume, transmission speed, flexibility, and antinoise properties so long as the conventional electric I/O is used. In order to resolve this interconnect bottleneck, the authors have developed an optical I/O interface ATM switch MCM in which the optical signal can directly enter and exit the MCM. This module is realized with 0.25‐μm CMOS LSI technology, 40‐layer ceramic MCM technology, ultra parallel optical interconnection technology and cooling technology. The size is 220 × 174 × 15 mm3and the switch throughput is 80 Gb/s. The optical I/O interface ATM switch MCM developed here is bookshelf installed in a rack and its fundamental operations are confirmed. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 85(2): 61–68, 2002
Theoretical Study of a Wave Absorber with Resistive Film for Metallic Cylinder
Authors: Iyomasa Kazuhiro , Hashimoto Osamu
Published: August 2002

This paper discusses the wave absorber which is best suited to use on cylinders with a resistive film. Mode expansion is applied in the analysis. Various design charts are provided. The effectiveness of the method is verified by designing a wave absorber using the design charts and calculating the absorbed power. This wave absorber is analyzed by calculating the power scattered by the wave absorber and the actually absorbed power. In addition, the degradation of absorbance due to deformation of the spacer in fabricating an absorber of this kind is examined by the point matching method. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 85(4): 53–60, 2002
Configuration and performance of a measuring system for spatiotemporal characteristics of multipath fading channels using a virtual planar array
Authors: Sekizawa Shinya , Taira Kazumasa , Kamio Yukiyoshi , Mizuno Mitsuhiko
Published: August 2002

As a remedy for multipath fading in land mobile communications, an adaptive array combined with an equalizer has been studied. For hardware realization and development of an adaptive algorithm for the fading prevention technique based on this temporal and spatial processing, it is necessary to clearly determine such spatiotemporal characteristics as the delay time and the directions of arrival of multipath waves. In this paper, in order to measure the spatiotemporal characteristics of multipath channels, a spatiotemporal propagation measurement system at 3.35 GHz has been developed by using a virtually realized planar array and a delay profile measuring equipment. The effectiveness of the present system is confirmed by measurement of the spatiotemporal characteristics in the simulated propagation path on an open site, and also in a real propagation channel in an indoor environment. © 2002 Scripta Technica, Electron Comm Jpn Pt 1, 85(6): 11–22, 2002
A multisensor tracking system with an airborne sensor to mitigate the effect of cross‐range errors
Authors: Kawamoto Daisuke , Kawase Tetsuya , Hashirao Masataka , Sasase Iwao
Published: August 2002

In this paper, we propose a multiple radar target tracking system that uses a mobile station, which is effective in reducing cross‐range errors. The mobile station is an airplane equipped with radar and tracks the target by radar while in flight. By controlling the motion of the mobile state according to the proposed algorithm, the beams from the radars to the moving target can be orthogonal to or nearly orthogonal to each other compared to a multiple radar target tracking system that uses only conventional stationary stations. Combining the measurements from radars placed so that their beams to the target are orthogonal or nearly orthogonal can lessen the effect of increases in the cross‐range errors and can obtain excellent tracking accuracy. Computer simulations compare the proposed method to a multiple radar target tracking system that used only conventional stationary stations and demonstrate its ability to obtain excellent tracking accuracy for distant targets. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(8): 1–12, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1113
An analysis of the effective radiation efficiency of the normal mode helical antenna close to the human abdomen at 150 MHz and consideration of efficiency improvement
Authors: Ogawa Koichi , Koyanagi Yoshio , Ito Koichi
Published: August 2002

In this paper, a new radiation efficiency based on the available power is defined with regard to a normal mode helical antenna at 150 MHz placed close to the human abdomen, so that the power loss caused by impedance mismatch and by the resistance of the antenna itself can be taken into consideration in the treatment. In this way, the variation of the effective radiation efficiency of the antenna in a practical situation caused by the antenna length and the distance to the human body is analytically derived. Further, by deriving the loss power in each section, the factors causing degradation of the radiation efficiency are analyzed and the mechanisms for efficiency degradation are clarified. Based on the results, the possibility of improved radiation efficiency of the antenna near the human body is discussed. It is shown that the radiation efficiency of the antenna near the body is less than −20 dB, that its main cause is impedance mismatch, and that improvement of the radiation efficiency by more than 10 dB is possible by always maintaining conjugate match near the human body. These findings are experimentally confirmed. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(8): 23–33, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1115
An analysis of a door seal structure of a microwave oven with an inserted sheet‐type lossy material using FDTD method
Authors: Matsumoto Kouta , Kusama Yuusuke , Hashimoto Osamu
Published: August 2002

By means of the three‐dimensional FDTD, the shield effect is studied for a sheet‐type lossy material inserted in the gap between a microwave oven body and its door as a way to suppress the microwave leakage in place of the generally used choke structure. Specifically, the shield effect versus the inserted length of the lossy material and the gap is studied by means of the TE40 mode, which has the closest shape to the leakage field among various higher‐order modes. It is shown that a shield effect of more than 30 dB can be exhibited if a certain lossy material completely fills the gap and that the inserted length of more than 50 mm is needed to obtain a shield effect of more than 30 dB if there is gap of 1 mm. Hence, the shield effect in a practical situation is quantitatively confirmed. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(9): 13–20, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1121
A frame timing and carrier frequency synchronization scheme for OFDM using frequency‐shifted signal
Authors: Konishi Muneo , Hosokawa Taisuke , Maeda Tsuyoshi , Takahata Fumio
Published: August 2002

This paper proposes a scheme for realizing simultaneously frame timing and carrier frequency synchronization in OFDM systems for wireless packet communications. Data symbols, which are frequency shifted by the half of subcarrier spacing based on the pattern of Barker sequence, are utilized as pilot symbols for the synchronization. The reduction of transmission efficiency could be minimized by carrying the data information on the pilot symbols. The performance evaluation by means of computer simulation demonstrates the good characteristics of the proposed system against the small Doppler frequency shift. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(10): 74–83, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1133
A study on efficient information search with agents in a large‐scale network
Authors: Sugawara Shinji , Ohshima Takamitsu , Yamaoka Katsunori , Sakai Yoshinori
Published: August 2002

In this paper, we study improving the efficiency of search methods to search a huge, superdistributed data space like the Internet. Specifically, in a search for information by agents, we first classify the search problems into several models based on the type of agent. Next, we determine the optimal search method that minimizes the communication and processing costs and the time costs for the basic model. Then we extend the optimal technique, propose highly efficient search methods for the other models, and evaluate their characteristics. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(10): 84–95, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1134
A consideration of multipath detection in navigation systems
Authors: Tajima Hirohisa , Fukushima Sonosuke , Yokoyama Hisasi
Published: August 2002

Some navigation systems measure the range or the angle by detecting the position of the pulse waveform. They cause some position detection errors, if the multipath wave overlaps with the direct wave with different position and phase. This paper presents a multipath detection method to improve the integrity of these systems. The results of simulation and ground‐based experiment for DME/P are described as an example, which use dual function of time‐of‐arrival detection. Each function is supposed to have a different multipath error characteristic. In addition, its multipath error detection method and application to MLS and GPS are also described. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(11): 52–59, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1137
An adaptive access control scheme for a reservation TDMA/adaptive modulation system
Authors: Watanabe Kazumi , Sampei Seiichi , Morinaga Norihiko
Published: August 2002

In realizing multimedia communication systems in land mobile communications, high‐frequency efficiency must be achieved, while satisfying various requirements for transmission quality depending on the media. In the proposed system, voice and the data of long message size are transmitted by the reservation TDMA (time division multiple access) system, and data of shorter message size are transmitted by the slotted ALOHA system, using slots which are not used for voice or long data. In order to ensure a larger number of idle slots for short data transmission, the voice activation technique and adaptive modulation are utilized in voice transmission. This paper considers the reservation TDMA/adaptive modulation system, and the transmission of voice/data integrated traffic at high speed and high efficiency through the common radio channel. An adaptive access control system is proposed in which the threshold for separating long and short data is automatically controlled according to traffic variation. It is verified by a simulation that the proposed system is effective in integrating data with high efficiency and in reducing delay in data transmission, while maintaining the voice transmission capacity. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(11): 77–86, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1140
Raising accuracy in the finding of radiated emission sources utilizing the CISPR emission measurement system
Authors: Ishida Yasuhiro , Murakawa Kazuo , Yamashita Kouji , Tokuda Masamitsu
Published: August 2002

In order to mitigate the emission radiated from electrical equipment, emission source finding methods need to be studied. In this regard, the finding method utilizing CISPR emission measurement system, which uses only amplitude data, has been proposed. However, there were some problems related to calculation convergence and dependence on initial source positions, as a result of which the finding accuracy decreases in some cases. In this paper, it is shown that the finding accuracy in this method is greatly raised when the calculation convergence is improved by optimizing Marquardt's constant, and the estimated sources are initially given at the optimum positions by taking into account the deviation (Norm) between the measured electric field and the estimated one. In order to experimentally verify this finding, unknown sources were estimated by using electric field data measured at a distance of 3 m in a semianechoic chamber, where two simulated emission sources were placed 0.4 m apart. Accurate estimated values were obtained, namely, a position estimation deviation of 0.09 m and an amplitude estimation deviation of 0.29 dB at 500 MHz. Additionally, the finding accuracy is raised by adding the directivity of the source and the receiving antenna. Furthermore, results in a fully anechoic chamber, in which the floor is covered with an electric wave absorber, show good finding accuracy, equivalent to that in a semianechoic chamber. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(6): 50–59, 2001
Performance evaluation of PRML systems using rate 9/10 trellis codes
Authors: Saito Hidetoshi , Okamoto Yoshihiro , Osawa Hisashi
Published: August 2002

Trellis codes are a form of recording codes considered to have good compatibility with PRML systems, which are signal‐processing systems that are effective for digital magnetic recording. In this paper, trellis codes which are compatible with PR4 and EPR4 are constructed by a set partitioning method. The best trellis codes are constructed by defining a signal constellation on the basis of output symbols allowing a partial response scheme and by partially dividing sets on a multidimensional Euclidean space. It is shown that trellis codes having a coding rate of 9/10 and bundle lengths of 6 and 7 can be obtained for PR4 and EPR4 systems using Nyquist equalization, and that the SN ratios are improved by 2.4 and 2.3 dB for the existing 8/9 (0,4/4) codes for the PR4 system and 16/17 (0,6/6) codes for the EPR4 system at a bit error rate of 10–4. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(7): 58–65, 2001
Production of binary holograms with laser punch
Authors: Iwai Yoshiaki , Nakajima Masato
Published: August 2002

A method for fabrication of binary holograms with a laser punch is proposed. In the present method, the hologram pattern is first computed in a computer so that a given reconstruction image can be obtained. This hologram pattern is binarized by a newly proposed algorithm. Based on the binary hologram pattern, laser illumination and motion of the stage with a film attached are computer controlled. In this way, holes with a fixed diameter are punched into the film to form binary holograms. Further, in order to verify the method's effectiveness, it is confirmed that excellent reconstruction images can be obtained from the holograms fabricated by the proposed method. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(10): 17–23, 2001
Content distributing algorithm for replicated Web servers based on market models
Authors: Nishimura Kenji , Yamamoto Miki , Ikeda Hiromasa
Published: August 2002

A content distributing algorithm based on market models for a replication distribution scheme of Web contents is proposed. In general, replication distribution is considered to effectively utilize the time and space local properties of access from a client and has been the topic of numerous studies. However, maintaining QoS (such as shortening the content obtaining time) in replicated servers when servers are in a congested state has not been considered in these studies. Since replicated servers constitute a resource shared by multiple ISPs (Internet Service Providers), the accesses need to be limited to replicated servers in case of a congested state to maintain the QoS enjoyed by each client. Thus, in this paper, a scheme for determining allocation of access to replicated servers for each content during congestion based on market models is proposed. The analytical and simulation results have confirmed that the proposed method controls the QoS in accordance with the access arrival rate to each content. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(11): 9–19, 2001
In‐situ observation of GaAs surface in high vacuum by contact angle measurement
Authors: Matsushita Koichi , Monbara Takuya , Nakayama Ken , Naganuma Hiroshi , Okuyama Sumio , Okuyama Katsuro
Published: August 2002

We developed an apparatus to measure the contact angle formed by a Ga droplet adhering to a GaAs substrate and the GaAs surface to understand the surface state of a GaAs substrate maintained at a substrate temperature in the range of 20 to 550 °C in a high vacuum. The following results were obtained by this apparatus. The contact angle of a Ga droplet on a GaAs(100) substrate with a grown oxide film had the value of 140° in a vacuum independent of the substrate temperature and showed no variation in the wettability. The contact angle decreased as the wettability improved and the substrate temperature increased when the oxide film was removed. Furthermore, the degree of wetting depends on the surface orientation of the GaAs substrate. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(11): 51–59, 2001
Asynchronous current‐mode multiple‐valued VLSI system based on two‐color two‐rail coding
Authors: Hanyu Takahiro , Kameyama Michitaka
Published: August 2002

In deep submicron VLSI, the asynchronous data protocol is a known technique to solve the performance degradation and increase in power dissipation problems arising from wiring such as cross queues. In this paper, we propose a new asynchronous multiple‐valued data communication scheme without rest phases in multiple‐valued data transfers. This scheme uses two‐railR‐value complementary signal pairs, and the sum of the two‐rail signal pair is always a constant for “valid data.” Along with defining a two‐rail signal pair with each signal having an odd phase or an even phase, each signal level in the even phase is set to always be larger than in the odd phase. The sum of a two‐rail signal pair becomes the minimum and the maximum, respectively, of the odd phase and the even phase. Consequently, if the sum of the two‐rail signal pair is examined, the monotonicity can be maintained in data transitions in two phases, and valid data can be detected by a simple threshold calculation. Furthermore, an asynchronous control circuit layout based on the linear sum of a two‐rail signal pair focuses on “the ability to implement the linear addition of current only at the connections” and clearly shows the ability to implement a more compact system than current‐mode multiple‐valued circuit systems. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(11): 60–67, 2001
Scattering analysis of large‐scale cavities using the nonstandard FDTD method
Authors: Ohtani Tadao , Kudo Hironori , Kashiwa Tatsuya
Published: August 2002

The nonstandard FDTD method has been proposed for highly accurate numerical analysis of large structures. However, the conventional nonstandard FDTD has been defined only with isotropic grids, and hence the treatment of arbitrary cavity shapes has been severely restricted. In order to remove this restriction in this paper, the nonstandard FDTD method is extended to more general noniso‐tropic grids. First, the FD Laplacian for the nonisotropic grids is newly defined. From the expression for decomposition by the first‐order difference operator, the nonstandard FDTD equations are derived for nonisotropic grids. The physical meaning of the nonstandard FD method used in the nonstandard FDTD method is clarified. Next, by means of the nonstandard FDTD method extended to nonisotropic grids, a scattering analysis of large‐scale cavities is performed and its effectiveness is demonstrated. The results obtained by the nonstandard FDTD method agree well with the measured values, confirming that the nonstandard FDTD method is effective as a highly accurate scattering analysis method for large‐scale cavities. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(12): 8–16, 2001
Speeding up multiagent reinforcement learning by coarse‐graining of perception: The hunter game
Authors: Ito Akira , Kanabuchi Mitsuru
Published: August 2002

Reinforcement learning is a promising technique for making agents learn to cooperate in the real world. When we try to apply the technique to a practical problem, however, the slowness of learning due to the increased number of states becomes a bottleneck. We try to speed up learning by reducing the effective number of states by coarse‐graining of perceptions at the early stage of learning, and at the same time try to ensure the overall performance by switching back to complete perception later. By only switching the perception granularity, however, it is difficult to rectify bad habits acquired at the early stage of learning. Hence, we make a coarse‐grained perception learner and a complete perception learner work in parallel, and switch the learner used for action selection at an appropriate time. This technique makes possible both fast early‐stage learning and overall good performance. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(12): 37–45, 2001
Finding all solutions of piecewise‐linear circuits by using linear programming
Authors: Yamamura Kiyotaka , Tanaka Shigeru
Published: August 2002

An efficient algorithm is proposed for finding all solutions of piecewise‐linear (PWL) resistive circuits using linear programming (LP). This algorithm is based on a simple test (termed the LP test) for nonexistence of a solution to a system of PWL equations of the formPg(x) +Qx–s= 0 in a given region. In the LP test, the system of PWL equations is transformed into an LP problem, to which the simplex method is applied. Such an LP problem is obtained by surrounding the PWL functions by rectangles. In this paper, it is shown that the LP test can be performed very efficiently mostly by Phase II of the simplex method. Using the proposed techniques, the number of pivotings in the LP test becomes much smaller, which makes the algorithm very efficient. By numerical examples, it is shown that the proposed algorithm could find all solutions of relatively large scale circuits (including those where the number of variables is 200 and the number of linear regions is 10200) in practical computation time. © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 84(7): 1–11, 2001
Calculating the upper bound of the Multiple‐Choice Knapsack Problem
Authors: Nakagawa Yuji , Kitao Masachika , Tsuji Mitsuhiro , Teraoka Yoshinobu
Published: August 2002

An upper bound or a lower bound of the Multiple‐Choice Knapsack Problem can be calculated by solving LP relaxation. In 1979, Sinha and Zoltners proposed a branch‐and‐bound algorithm for solving the Multiple‐Choice Knapsack Problem, and provided a method to obtain the strict upper bound. In this paper, we propose a new calculation method to obtain a stricter upper bound than the upper bound of Sinha–Zoltners and compare the results of the two methods. © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 84(7): 22–27, 2001
Precise interpolation for band‐limited digital signals based on sampling theorem incorporated with window functions
Authors: Asai Takahiro
Published: August 2002

This paper proposes an interpolation method called the “window function method” in which the sampling theorem and the window functions are combined. The cause of the generation of the interpolation error is the folding distortion due to the multiplication of the time‐limited window to the input signal. The conditions to enable precise interpolation are that the functions are continuous, the windows with large spectral decays in the side lobes are normalized such that the window function values are unity at the interpolation points, and the main lobe width is set to an optimum. When the interpolation precision is compared with those by other interpolation methods, the present one is about the same as that in the “filter method” (the conventional method using the filter to eliminate the unwanted image components) but is somewhat poorer than that in the “least RMS error method” (theoretical limit) if Kaiser–Bessel windows are used. However, the number of input signal data to obtain the same interpolation precision is larger only by 10%. Hence, the operating time to obtain the required interpolation precision is close to optimum. The calculation of the coefficients needed for interpolation is basically a simple substitution and can avoid a design of higher‐order filters (in the filter method) and solution of the ill‐conditioned simulation equations (in the least RMS error method). © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 84(7): 63–77, 2001
Development of template matching hardware and its high‐speed processing strategy
Authors: Muramatsu Shoji , Kobayashi Yoshiki , Takahashi Kazuya , Shimizu Eiji
Published: August 2002

The template matching technique is now applied to tracking of outdoor object and position measurement, and there is increasing demand for application of template matching based on the normalized correlation coefficient, which is robust against the variation of illumination. In order to apply the technique based on the normalization technique to practical application problems, however, high‐speed calculation of the normalized correlation coefficient is required. This paper intends to improve the speed by implementing by hardware the calculation of the normalized correlation coefficient, which requires a large amount of computation. The proposed method decomposes the normalized correlation coefficient calculation into five operational components, each of which is implementated by hardware. The speed of processing is improved being combined with a parallel processing with a high degree of freedom based on the local property owned by the template matching process. For further improvement of the speed, the application of the pyramid structure is considered. Hardware that can handle the pyramid structure is realized. An evaluation was tried using an actual machine. The performance of the developed hardware is evaluated. The effectiveness of the approach is verified by applying the method to the traffic flow measurement system, as an example of an actual outdoor system. © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 84(11): 1–10, 2001
On selection rules for database compression using KDD
Authors: Aisaka Kazuki , Tsukamoto Masahiko , Harumoto Kaname , Nishio Shojiro
Published: August 2002

Despite the drop in disk prices in recent years, the costs associated with disks still represent the primary costs for large‐scale databases such as those used in data warehouses. Compression and storage of such databases is seen as an effective means to reduce these costs. The authors' research group has already proposed a compression method that exchanges the priority for rules and data after extracting rules latent in data by using knowledge discovery as a database compression method which can access a database in its compressed state. However, this proposed method has the problem of producing differences in the compression ratio due to the priority with which the extracted rules are used for compression. Simply finding all the combinations for the priority for the use of such rules is not practical, and so in this paper the authors propose a rule selection method which provides comparatively good compression ratios without excessive computational requirements, then demonstrate the validity of their method using experimental results. © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 84(11): 11–20, 2001
Recognition of human activities by gas sensor response using genetic algorithm
Authors: Hayashi Takahiro , Kimura Haruhiko , Oyabu Takashi
Published: August 2002

In this paper, a scheme for estimating gas concentration change signals for each gas generating source in a room from output signals of a combustible gas sensor installed in the room, and for estimating event signals synthesized from them by a genetic algorithm (GA), is proposed. It is shown by computer simulation that more accurately estimated concentration change signals or event signals are obtained by applying selective weeding, crossing, mutation, and so on, repeatedly to an individual group, while applying an appropriate evaluation function to concentration change signals and event signals estimated for each gas generating source expressed by a GA individual. In addition, it is shown that the estimated concentration change signals and estimated event signals obtained from the output signals of a gas sensor installed in an occupied room by the proposed scheme correspond approximately to human activities. In addition, it is shown that the proposed scheme is effective in detecting human activities with a gas sensor, since appropriate signals can be estimated robustly even though components such as noise may be present in the sensor output signals. © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 85(1): 50–61, 2002
Transient analysis of nonuniform transmission line using the finite difference time domain method
Authors: Sekine Toshikazu , Kobayashi Kunikatsu , Yokokawa Senji
Published: August 2002

With a view to accurate and fast time domain analysis of nonuniform transmission lines, a method is presented for applying the FDTD method to a finite length nonuniform transmission line. A step response analysis is carried out for a parabolic line as one of the nonuniform transmission lines. Effectiveness of this approach is confirmed by comparison with analytical solutions and other methods. An equation for the voltage at the initial rising duration of the step response of a nonuniform transmission line is derived. It is shown that if the nonuniform transmission line has the characteristic impedance with a continuous distribution the initial arriving voltage can be determined by the characteristic impedance at both ends of the transmission line. As an application, a method is described for approximating the step response waveform of a parabolic line to a step wave. © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 85(2): 22–31, 2002