bluuebunny/crossref_metadata_2025_split huggingface dataset:
Linked regulation of motility and integrin function in activated migrating neutrophils revealed by interference in remodelling of the cytoskeleton
Authors: Anderson Stephen I. , Behrendt Barbara , Machesky Laura M. , Insall Robert H. , Nash Gerard B. 
Published: January 2003

AbstractNeutrophils migrate rapidly by co‐ordinating regulation of their β2‐integrin adhesion with turnover of filamentous F‐actin. The seven‐protein Arp2/3 complex regulates actin polymerisation upon activation by proteins of the WASP‐family. To investigate links between actin polymerisation, adhesion, and migration, we used a novel osmotic‐shock method to load neutrophils with peptides: (1) WASP‐WA and Scar‐WA (which incorporate the actin‐ and Arp2/3‐binding regions of WASP and Scar1), to compete with endogenous WASP‐family members; (2) proline rich motifs (PRM) from the ActA protein of L. monocytogenes or from vinculin, which bind vasodilator‐stimulated phosphoprotein (VASP), a regulator of cytoskeleton assembly. In a flow system, rolling‐adherent neutrophils were stimulated with formyl tri‐peptide. This caused rapid immobilisation, followed by migration with increasing velocity, supported by activated β2‐integrin CD11b/CD18. Loading ActA PRM (but not vinculin PRM) caused concentration‐dependent reduction in migration velocity. At the highest concentration, unstimulated neutrophils had elevated F‐actin and were rigid, but could not change their F‐actin content or shape upon stimulation. Scar‐WA also caused marked reduction in migration rate, but WASP‐WA had a lesser effect. Scar‐WA did not modify activation‐dependent formation of F‐actin or change in shape. However, a reduction in rate of downregulation of integrin adhesion appeared to contribute to impaired migration. These studies show that interference in cytoskeletal reorganisation that follows activation in neutrophils, can impair regulation of integrin function as well as motility. They also suggest a role of the Arp2/3 complex and WASP‐family in co‐ordinating actin polymerisation and integrin function in migrating neutrophils. Cell Motil. Cytoskeleton 54:135–146, 2003. © 2003 Wiley‐Liss, Inc.
A study on millimeter‐wave absorber coating for V band and W band
Authors: Soh Tetsu , Hashimoto Osamu 
Published: January 2003

AbstractIn order to realize a coating‐type millimeter wave absorber superior in weather resistance for outside use, the absorption characteristics at 50 to 110 GHz are studied for titanium dioxide and epoxy resin containing carbon particles. It is found that the frequency dependence of the complex relative permittivity of the material doped with 32 phr of titanium dioxide and 1 phr of carbon particles varies almost in parallel with the reflectionless curve and that both the real and imaginary parts tend to decrease as the frequency is increased. It is shown theoretically and experimentally that coating‐type millimeter wave absorbers made to have absorption characteristics of more than 23 dB at the maximum can be obtained at an arbitrary frequency in the 50 to 110 GHz range by simply changing the thickness, and that the frequency range with an absorption of more than 20 dB exceeds 5 GHz. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(5): 52–58, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10017
Transmission performance of reservation ALOHA access schemes with variable length packets
Authors: Umeda Hiroyuki , Tanabe Hidehiko , Hayano Mitsuru 
Published: January 2003

AbstractWe propose a hybrid reservation ALOHA access scheme as an efficient transmission access scheme for variable length packets. A packet group having an integral packet length distribution from 1 to m, where m = 2k for a positive integer k, is divided into a group of m/2‐long fixed length packets and a group of 1 to m/2‐long packets. The fixed length packets become the reservation packets. The remaining packets are transmitted by the ALOHA access scheme. The maximum throughput in this scheme reaches about 0.39. Furthermore, the 2‐multiplexed hybrid ALOHA reservation scheme divides the packet group of packets having packet lengths from 1 to m/2 into m/4‐long fixed length packets and a packet group having packets of lengths of m/4 or less, and transmits the m/4‐long fixed length packets in the second reservation slot and the packets having the remaining lengths in the ALOHA slot to reach a maximum throughput of 0.57. These throughput values are used to study the suitability from the two perspectives of a theoretical analysis and a simulation. Finally, we try to improve the delay performance by assigning a number to the ALOHA slot and efficiently retransmitting the collision packets according to the number table. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(5): 42–51, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10019
A beam pattern selection diversity technique using adaptive array antenna for DS/CDMA cellular systems
Authors: Watanabe Katsumi , Sampei Seiichi , Morinaga Norihiko 
Published: January 2003

AbstractThis paper proposes a beam pattern selection diversity technique using an adaptive array antenna. In the system using an adaptive array antenna, beam control in the uplink is carried out for all terminals in the cell. Hence, it is necessary to determine the antenna weights for all terminals at the base station, so that the amount of computation is increased and the base station configuration becomes complex in a cellular system that seeks to be capable of handling as many terminals as possible. In this paper, the beam patterns are generated only for a limited number of terminals in the cell, while other terminals share the generated radiation patterns, so that the amount of computation can be reduced substantially. In general, in a system using an adaptive array antenna, the interference suppression capability is significantly affected by the angle of arrival of the propagation channel. In this paper, the angle of arrival of the channel is modeled by a normal distribution and the proposed system is investigated in a micro‐cell environment. As a result of numerical simulation, it is found that the proposed method can reduce the processing effort by 20% in the micro‐cell environment, while the characteristics are sufficiently competitive with the results obtained when optimum radiation patterns are generated for all terminals. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(5): 32–41, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10020
An influence on radiation characteristics by FSS on a beam‐waveguide feed with FSS
Authors: Miyahara Norio , Mizuno Tomohiro , Matsumoto Soichi , Deguchi Hiroyuki , Urasaki Shuji 
Published: January 2003

AbstractDual reflector antennas fed with a beam waveguide are widely used for base stations of satellite communication and for radio astronomy. When the antenna is used at several frequencies, it is effective to carry out diplexing with a frequency selective surface (FSS) in the beam waveguide. Traditionally, when an antenna containing an FSS on the reflector surface is designed, or its radiation characteristics are evaluated, it is assumed that the FSS is ideal and it is modeled by a metal plate or a transparent plate in order to derive the radiation characteristics of the antenna at the frequency range in which the FSS is used for transmission or reflection. Next, the return loss or transmission loss of the FSS alone is derived. This loss has been considered as gain reduction of the radiation characteristics of the antenna with an ideal FSS. However, since the reflection and transmission characteristics of the FSS differ depending on the angle of incidence and polarization angle of the wave incident on the FSS, the radiation pattern of the entire antenna system and that of the wave that is incident on the focusing reflector connected to the FSS are different from those obtained when using a focusing reflector modeled by an ideal FSS. Hence, for accurate design and evaluation of a dual reflector antenna fed by a beam waveguide using an FSS, the effect of the reflection and transmission characteristics of the FSS on the radiation characteristics must be considered in addition to the loss caused by the FSS. This paper studies the effect of the FSS on the radiation characteristics when a dual reflector fed by a beam waveguide with an FSS partially installed is excited by the fundamental mode (EH11) of the primary radiator. For calculation of the electromagnetic field in the beam‐waveguide feed, the beam mode expansion method is used, so that the wave effect is taken into account. For calculation of the reflection and transmission characteristics of the FSS, a simple method is used in which the electromagnetic field scattered by the FSS is expanded in terms of Floquet modes and the electric field on the FSS is determined by the method of moments. Further, in order to reduce the effect on the radiation characteristics resulting from the difference in reflection phase at the metal part and at the FSS, the location of installation of the FSS is offset so that the phase difference of the reflected waves from two regions is compensated. This proposed method is found effective. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(5): 21–31, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10041
Calculation of electric far field radiated from transmission line attached to a ferrite core above a ground plane
Authors: Maekawa Tetsuya , Fujiwara Osamu 
Published: January 2003

AbstractThe use of magnetic materials has drawn attention as a method of simultaneously realizing suppression of electromagnetic (EM) noise radiated from information devices and improvement of the immunity of such equipment against the EM noise from these devices. Suppression effect of the electromagnetic noise radiated from printed circuit boards (PCB) traces and cables by ferrite cores and sheets has been studied. However, little is known about the relationship between the mounting location of the ferrite materials and the noise suppression effect. In this paper, a transmission line on the ground plane for the transverse electromagnetic mode is treated. The radiated field at a sufficient distance relative to the transmission line length is analyzed. It is shown that the field level in this case is proportional to the spatial average value of the current distribution on the transmission line in the length direction and hence that reduction of the field level is possible by suppressing the average value of the current. Next, a computational formula is derived for the field level from the ferrite core‐attached transmission line. Using this formula, the suppression effect of the field level by core attachment is numerically studied. It is found that a suppression effect is recognizable if the ferrite core is installed at the near end of the transmission line. On the other hand, the field level actually increases if the ferrite core is installed at the far end. These numerical results are confirmed to agree well with experimental results obtained in a six‐surface anechoic chamber. Hence, the formula derived in this paper is valid. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(5): 12–20, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10050
Performance of the delay profile information channel based subcarrier transmit power control technique for OFDM/FDD systems
Authors: Maeda Noriyuki , Sampei Seiichi , Morinaga Norihiko 
Published: January 2003

AbstractThe convolutionally encoded OFDM (Orthogonal Frequency Division Multiplexing) scheme, is an effective approach that is superior in its robustness to frequency‐selective fading and in assuring high transmission quality in a broadband wireless transmission system. However, since the burst length becomes shorter as the transmission speed becomes higher, there are problems of reduced coding gain due to lack of interleaving effect and of increased transmission power with increased bandwidth. These problems are particularly significant in the application to indoor environments in which the demand for high‐speed transmission is high and the Doppler frequency is small. Hence, further improvement of receiver sensitivity and reduction of transmit power are indispensable. In this paper, a subcarrier transmit power control technique is proposed in which the delay profile information estimated using a pilot channel is reported to the message sender and the transmit power is controlled to make the receiving condition for each subcarrier constant based on the obtained delay profile information, so that the receiver sensitivity is improved by transmit power control. Further, the use of PNPA (Partial Non‐Power Allocation), which suppresses excessive transmit power caused by the application of the subcarrier transmit power control, is considered. When the transmission characteristics of the proposed scheme are evaluated by computer simulation, it is confirmed that the error correcting capability can be improved drastically by the proposed scheme and that the transmit power can be reduced substantially. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(5): 72–80, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1163
Performance enhancement and compensation of carrier frequency offset using CRA‐AA for uplink in SDMA system
Authors: Kishiyama Yoshihisa , Nishimura Toshihiko , Ohgane Takeo , Ogawa Yasutaka , Doi Yoshiharu 
Published: January 2003

AbstractRecently, the Space Division Multiple Access (SDMA) scheme has been proposed to improve channel utilization efficiency. SDMA requires separation and detection schemes in the base station because serious interference develops among all of the users accommodated by the same channel. In this paper, we propose the Channel Response Assisted Adaptive Array (CRA‐AA) that estimates the channel response in the uplink and uses this result to indirectly control the directivity, and compare its performance to those of MMSE adaptive array and joint detection. We also study a scheme to compensate for the carrier frequency offsets generated at each user. We found that CRA‐AA had superior performance in the presence of both fast fading and carrier frequency offsets. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(5): 81–91, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1164
Performance evaluation of all‐optical network with limited‐range wavelength conversion: The case of multiple fibers on a link
Authors: Miyamoto Kentaro , Harai Hiroaki , Murata Masayuki , Miyahara Hideo 
Published: January 2003

AbstractNetwork performance is improved by performing wavelength conversions in an all‐optical network. However, performing wavelength conversions entirely by current wavelength conversion techniques is difficult. Although the network performance is improved by having multiple optical fibers on each link, the network cost is inevitably increased. In this paper we propose a layered graph method which can simply describe a routing/wavelength assigning problem of a network with a limited‐range wavelength conversion capability in which a link has multiple fibers, together with an algorithm for routing/wavelength assignment using a hierarchical graph. In addition, the effects of wavelength conversions and multiple fibers and the performance from the cost point of view are studied by simulation. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(5): 92–101, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1165
Full‐vector finite‐element beam propagation method for three‐dimensional nonlinear optical waveguides
Authors: Fujisawa Takeshi , Koshiba Masanori 
Published: January 2003

AbstractA full‐vector beam propagation method based on the finite‐element method (VFE‐BPM) for analysis of a three‐dimensional nonlinear optical waveguide is newly developed with all slowly varying electric field components as unknown variables. The derived electric field can be used directly for evaluation of the nonlinear refractive index, so that a nonlinear refractive index directly corresponding to the electric field can be obtained. Various methods are included for improving the performance of the VFE‐BPM such as the edge/nodal hybrid elements for suppressing generation of spurious solutions, the anisotropic perfectly matched layer for prevention of spurious reflection from the analysis domain edges, and an iteration method to relax the step width in the propagation direction. Further, a beam propagation analysis is carried out for spatial soliton emission phenomena in a three‐dimensional nonlinear optical waveguide for performance evaluation of the VFE‐BPM developed here. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(2): 19–27, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10079
Calculation of radiation pattern from nonperiodic dielectric waveguide and synthesis of conical beams
Authors: Kubo Hiroshi , Fukuoka Yasuhiko , Awai Ikuo 
Published: January 2003

AbstractSynthesis of radiation patterns is carried out by installing many shape variations on the surface of a dielectric rod waveguide. First, an approximate analysis method using a four‐port circuit is presented for calculating the radiation characteristics in a short time. This method for calculation is combined into a genetic algorithm to derive the configuration of the shape variations. Several modifications are used in the genetic reconstruction method in order to adapt the problem to a synthesis of the radiation patterns by the configuration of the shape variations. Synthesis of conical beams with different radiating angles and beam widths is carried out. The radiation characteristics are compared with those by the periodic waveguide structure. In regard to the radiation pattern of a dielectric rod antenna with derived shape configuration, the results by the approximate method and the FDTD (finite difference time domain) method agree well. This is confirmed by experiment. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(2): 9–18, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10084
A 50% duty‐cycle correction circuit for PLL output
Authors: Ogawa Toru , Taniguchi Kenji 
Published: January 2003

AbstractWe proposed a circuit for correcting the fluctuations in the duty cycle caused by the increase in the device fluctuations due to the miniaturization of MOS devices and faster operating speeds. This correction circuit uses feedback control consisting of duty‐cycle detection and correction to correct the fluctuations in the duty cycle of a phase‐locked loop (PLL) circuit produced during the manufacturing process. A prototype of the proposed circuit having a 5‐V power supply voltage was fabricated using a 0.6‐µm process and measured. The variations in the duty cycle of the output voltage for an input signal having 20% to 80% duty cycle fluctuations could be suppressed to 0.21%, which is a 1/300 suppression of the input signal duty cycle fluctuations. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(2): 1–8, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10085
Model‐based speaker normalization methods for speech recognition
Authors: Naito Masaki , Deng Li , Sagisaka Yoshinori 
Published: January 2003

AbstractA speaker normalization method using a speech generation model is proposed in order to achieve high‐performance speaker adaptation with a small amount of adaptation data. The speaker‐ and phoneme‐dependent vocal tract area function is approximated by the corresponding area function produced by the articulatory model of a standard speaker, combined with phoneme‐independent feature quantities of the vocal‐tract shape of the normalized target speaker as estimated from the formant frequencies of two vowels. The frequency warping functions are determined from the formant frequencies of speech calculated from the vocal‐tract area functions thus obtained, and normalization of the uttered speech is performed by stretching the speech spectrum in the frequency‐axis direction. Continuous phoneme recognition experiments using phoneme connection rules show that the recognition error using a gender‐dependent model is reduced by about 30% in the proposed method and that recognition performance superior to that of vocal‐tract length normalization is obtained. The recognition performance of the proposed method is also equivalent to that of speaker adaptation by moving vector field smoothing (VFS) using 10 phonetically balanced sentences, showing that high‐performance speaker adaptation using a small amount of adaptation data can be achieved by the proposed method. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(2): 45–56, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10119
A DFT method for BIST of RTL data paths based on single‐control testability
Authors: Izutsu Minoru , Wada Hiroki , Masuzawa Toshimitsu , Fujiwara Hideo 
Published: January 2003

AbstractIn this paper, as a built‐in self‐test (BIST) scheme for register transfer level data paths, we will propose a BIST of the test per clock scheme based on hierarchical testing. In this technique, test pattern generators and response analyzers are added only to primary inputs and primary outputs of circuit under test; and for the respective combinational circuit elements, the test patterns and corresponding responses are propagated by using paths on a data path. In this paper, as a data path capable of BIST based on this hierarchical testing, we will define a single‐control testable data path, and propose a design for testability method for changing the design from a given data path to a single‐control testable data path. Moreover, the evaluation of the proposed technique is performed using benchmark circuits. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(2): 84–93, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10122
Use of a percolation model to analyze the characteristics of a novel scheme for fabricating silicon‐based visible light‐emitting layers by photochemical etching
Authors: Yamamoto Naokatsu , Takai Hiroshi 
Published: January 2003

AbstractResearch focusing on efforts to create visible light‐emitting materials starting with silicon is important to the development of future silicon‐based optoelectronic devices. In this paper, we describe a novel process based on surface photochemical reactions, that is, “photochemical etching,” for fabricating silicon‐based visible light‐emitting materials. We studied the characteristics of visible‐light emission from the photochemically etched layers by observing the photoluminescence excited by a He‐Cd laser, and the structural characteristics of these layers by monitoring their hydrogen content using the method of hydrogen forward scattering. We found that the photochemically etched layers exhibited strong photoluminescence, which could easily be detected by the naked eye in bright ambient light. In this paper we also attempt to qualitatively describe the etching process, using what we refer to as the “inverse percolation model.” This model allowed us to correlate the emission characteristics of the photochemically etched layer with its structural characteristics. By using this percolation‐based model, we were able to investigate the photochemical etching method theoretically, from which we concluded that it can be the basis for an important process that will lead to the fabrication of silicon‐based materials capable of emitting visible light with high emission intensity. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(2): 36–44, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.1117