bluuebunny/crossref_metadata_2025 huggingface dataset:
Communication control mechanism to adapt the quality change of a communication channel
Authors: Taniguchi Hideo , Noguchi Yusuke , Nomura Yoshinari
Published: August 2002

In this paper, we describe a communication control mechanism that can dynamically adapt to the quality changes of a communication channel. Specifically, we propose a communication control mechanism that adapts to the quality changes of the communication channel. To implement this mechanism, we model the communication flow and derive equations for the communication time and the optimum window size that minimizes the communication time. The problems of existing communication control protocols are explained, and a new communication control protocol that solves these problems is presented. Furthermore, to implement a communication control mechanism employing the optimum window size, we propose a simple equation for the optimum window size and demonstrate its effectiveness by evaluating the implementation of the communication control mechanism. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(11): 1–12, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10015
Mobile communications higher‐order‐mode microstrip antennas for road vehicle communications
Authors: Kazama Yasuhiro , Morita Nagayoshi , Tokumaru Shinobu
Published: August 2002

Car antennas for road vehicle communications systems should be able to receive constantly the signals of beacon antennas at positions from just below the beacon antenna to a great distance along the road. In this paper, we restrict the discussion to the case of microstrip antennas and investigate what kind of patch shape is suitable for car antennas used in road vehicle communications systems. As a measure for evaluating the receiving power level, we define and use the “effective directivity,” which takes account of the distance between the beacon antenna and car antenna and the relative arrangement of both antennas. This effective directivity represents the effective received electric field intensity. We examine various patch shapes from the viewpoint that the desirable ones have constant effective directivity irrespective of car position. As a result, three types of simple‐structure higher‐order‐mode microstrip antennas are proposed. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 84(11): 54–60, 2001
Multireflector offset antennas eliminating cross‐polarization component based on beam mode analysis
Authors: Furuno Takayoshi , Urasaki Shuji , Katagi Takashi , Ikuno Hiroyoshi
Published: August 2002

This paper presents the general cross‐polarization elimination condition for multireflector offset antennas consisting of one primary horn and many reflectors. It clarifies that the derived condition is a frequency‐independent geometrical relationship. We apply this condition to an offset parabolic antenna, a dual reflector offset antenna, a trireflector offset antenna, and a four‐reflector offset antenna, and show that a trireflector offset antenna is consistent with the already derived relationship. Furthermore, the configurations for the reflector system obtained by applying this condition to a four‐reflector beam waveguide feed are shown, and the general broadband characteristic condition is derived, which is especially important for the broadband design.

To determine the validity of the theory, a design example is presented for a beam waveguide feed satisfying the cross‐polarization elimination condition and the broadband characteristic condition, and minimizing the spillover loss within the structural restriction of using a four‐reflector beam waveguide feed. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 84(12): 1–12, 2001
Performance analysis of noncollision PRMA for data and voice traffic
Authors: Tadenuma Mioko , Arakawa Osamu , Sasase Iwao
Published: August 2002

In reservation radio packet transmission protocols, non‐collision packet reservation multiple access (NC‐PRMA) is known to be able to transmit packets without any collision and to attain higher throughput than packet reservation multiple access (PRMA). However, so far only NC‐PRMA in voice‐only traffic has been studied. In this paper we evaluate NC‐PRMA in integrated voice and data traffic. First, considering data terminals, we formulate an equilibrium point analysis by guaranteeing the number of slots for data packet transmission in one frame. The number is decided according to the number of terminals. Next, we evaluate the throughput and the voice packet dropping probability by theoretical analysis and computer simulation. It is shown that in integrated voice and data traffic NC‐PRMA attains better throughput and voice packet dropping probability than PRMA. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 84(12): 13–21, 2001
A theory of unwinding optic fiber's motion for fiberoptic data link bobbin
Authors: Akiyama Akira , Shibata Mitsuru , Araki Shinji , Ishii Hiromitsu
Published: August 2002

Recently, development of mobile communications facilities using fiberoptic data link bobbins have been carried out in which highly densely wound, extremely fine, high‐capacity, low‐loss optical fiber is unwound into free space over a long distance from a supersonic platform. In unwinding during high‐speed flight, air resistance, tension, friction, and inertia are applied suddenly to the ultrafine optical fiber. These forces jointly deform the winding shape of the optical fiber suddenly, with the result that transmission loss may be increased and the optical fiber may be broken. For the development of fiberoptic data link bobbins with ultrafine optical fiber, an analysis of the unwinding motion of the optical fiber, systematically taking account of the forces acting on the fiber, is indispensable. In this paper, a spatial unwinding theory is derived that can handle the dynamic behavior of the optical fiber as the basis for design and fabrication of fiberoptic data link bobbins that unwind optical fiber into the air. The solution method and a numerical simulation are compared with the results of an underwater unwinding test, simulating the Reynolds similarity rule with a high‐speed unwinding bobbin fabricated for test. It is shown that the present theory can effectively analyze the unwinding behavior of the optical fiber when a high‐speed unwinding bobbin is used. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 85(3): 61–73, 2002
Least‐mean‐squares design of filters controlling subband coefficient powers with applications to image coding
Authors: Ito Hiroshi
Published: August 2002

In image coding, the relationship between the coding rate and distortion depends on the input image. In coding that decomposes a signal into multiple frequency bands (subbands) as in the DCT and the wavelet transform, the power distribution of the decomposed signal (subband coefficients) is the primary factor that determines the rate‐distortion characteristics. In this paper, we propose a design method for prefilters that controls the powers of the subband coefficients. This design method assigns a target gain for the prefilter to each subband and determines the filter coefficients by least mean squares estimation. The input signal is used in the least mean squares calculation. Thus, if this filter is used in the stage prior to coding, the target rate distortion characteristics adapted to the input signal can be more faithfully achieved. By smoothly assigning the target gains to adjacent subbands, this prefilter can accurately achieve the target gains even for a low‐order analysis filter as in DCT. In addition, computer simulations demonstrated satisfactory performance when applied to image coding. © 2002 Scripta Technica, Electron Comm Jpn Pt 1, 85(5): 11–24, 2002
Timing and frequency‐based channel segregation of base stations for high‐speed wireless access systems
Authors: Iwatani Junichi , Okada Takashi , Aikawa Satoru , Matsue Hideaki
Published: August 2002

A method is proposed to segregate channels used by each base station in both time and frequency in the case of a high‐speed wireless access system. By means of this method, many base stations can be established in a high‐speed wireless access system in which the number of frequency channels is reduced as the bandwidth per wave becomes wider. Further, the frequency‐use efficiency is improved in the entire system. In this paper, the timing and frequency‐based channel segregation method is proposed. The base station channel segregation algorithm in which this method is applied to a specific system is presented. By means of computer simulation, the possibility of achieving base station segregation is evaluated. It is shown that the proposed method is effective in a high‐speed wireless access system. Experiments using test apparatus show the correct operation of the system. © 2002 Scripta Technica, Electron Comm Jpn Pt 1, 85(6): 64–74, 2002
Uplink polarization diversity measurement with human body effect at 900 MHz
Authors: Nakano Masayuki , Satoh Toshio , Arai Hiroyuki
Published: August 2002

A series of experiments were conducted on the uplink diversity characteristics for a mobile communication system using the random field method. In contrast to past belief, it was found that polarization diversity systems are much more effective than space diversity systems for mobile communications. This is due to the orientation of mobile antennas that are tilted about 60° from the zenith in normal conversation state and by the horizontal polarization component that is generated by the human body and mobile phone casing.

In addition to the above, a comparison of antenna radiating elements was also made— vertical/horizontal versus 45° crossed dipoles— on the diversity effect of the receiving system at the base station. It was found that the 45° crossed dipoles were slightly more effective than the vertical/horizontal elements in the case of line‐of‐sight coverage, but for out‐of‐sight coverage, the difference was not significant. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(7): 32–44, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/ecja.1109
Studies on design of optical receiver for TCM/TDMA passive double star systems
Authors: Tamaki Norio , Miki Noriki , Kumozaki Kiyomi , Watanabe Ryuichi
Published: August 2002

In order to transmit the communication services presently provided over an optical access network, a design of the optical transmission system of TCM/TDMA‐PDS (Time Compression Multiplexing/Time Division Multiple Access‐Passive Double Star) type is described. The gain control and timing extraction needed for TCM/TDMA transmission are clarified. It is shown that a transmission frame with a preamble is effective for these requirements. Further, design of the present frame is described. A design example of 49.152 Mbs TCM/TDMA‐PDS system and the measured results are presented. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(7): 61–70, 2002; Published online in Wiley Interscience (www.interscience. wiley.com). DOI 10.1002/ecja.1112
Analysis of tracking errors by direct observation of C/A code waveforms in GPS
Authors: Tachita Ryobun , Tsuchiya Manabu , Sasaki Masahiro , Ishigaki Toshihiro , Yasuda Akio
Published: August 2002

Delay Lock Loops (DLLs) are often used in code tracking in GPS receivers. The delay lock loop can reduce the code tracking errors produced by the multipath by decreasing the time difference in the reconstructed code being compared. Then, the bandwidth of the receiver is much wider than the chip rate of the code. In this paper, we propose a GPS receiver capable of measuring the code waveforms of satellite signals and use this prototype receiver to analyze the effects that the receive bandwidth has on the tracking error. We also propose a code tracking scheme called the Sampled Code Edge Lock Loop (SCELL) that implements this function. We then show that a method for analyzing the relationship between the receive bandwidth of the measured code waveform and the code tracking error caused by multipath, and the SCELL can suppress the errors in the code tracking caused by multipath. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(9): 42–50, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1124
A multiagent‐based adaptive QoS management scheme
Authors: Kosuga Masakatsu , Yamazaki Tatsuya , Ogino Nagao , Matsuda Jun
Published: August 2002

With the improvement of speed in personal computers and workstations for communication networks and communication terminals, various applications have been emerging in recent years based on multimedia communications, including stream‐type media. In these communication applications, there must be a framework by which the QoS of its stream is determined and adjusted to meet its own purposes according to the user's request and the situation of the terminal and the network. When such an adaptive QoS control mechanism is built in an individual communication application, however, the communication application will become complicated. It is thus desirable that the adaptive QoS control mechanism should be realized as a common basis for various communication applications. This paper proposes a framework to realize an adaptive QoS control mechanism that can serve as the common basis for various communication applications, based on direct or indirect collaboration by multiple agents. The proposed framework is implemented and its operation is verified. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(10): 96–105, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1135
Cavity‐backed slot array antenna with backward excitation
Authors: Yamamoto Manabu , Ishizaki Kosuke , Muramoto Mitsuru , Sasaki Kanemi , Itoh Kiyohiko
Published: August 2002

The slot array antenna with backward excitation is promising as a constituent element of a planar multisector antenna. This paper deals with a slot array antenna with backward excitation that prevents radiation into the backside by installing a cavity. With a view to simplifying the fabrication process, all slots in the array share one cavity. A design guideline is discussed for reducing mutual coupling between the elements. It is found that the cavity width should cause the TE10 mode to be cut off. For a four‐element array with a cavity satisfying this condition, the characteristics are evaluated by the spectral domain moment method. It is shown that a beam tilt toward the end fire direction can be obtained, similarly to the case without a cavity. The antenna characteristics are evaluated in terms of cavity length and depth. It is demonstrated that the effect of the cavity length on the antenna characteristics is significant and that the cavity thickness can be reduced. Further, a test experiment is conducted at 19 GHz to confirm the validity of the numerical study. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(11): 68–76, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1139
Color balancing filters using liquid crystal for image pickup
Authors: Yonai Jun , Fujikake Hideo , Aida Tahito , Kikuchi Hiroshi , Kawakita Masahiro , Takizawa Kuniharu , Iwashita Kenichi , Umeda Shinya
Published: August 2002

In order to correct the color deviation due to variation of illumination in film shooting, a liquid‐crystal filter with dichroic dyes that can control the color temperature of the transmitted light in real time has been developed. By using Planck's radiation rule and the Lambert–Beer law, the absorption spectra of the dyes are designed. It is found that the color balance can be adjusted continuously between 4450 and 2530 K. The time needed for control is about 80 ms. When a liquid‐crystal filter is used for actual television film shooting, it is confirmed that the color balance of the image can be corrected naturally. The present device is useful in location film shooting for television when the color temperature of the image changes drastically under such conditions as the lighting changing from indoor light to solar light. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(10): 40–48, 2001
Hybrid Finite‐Element Analysis of Surface Acoustic Waveguides with One‐Wavelength Period along Propagation Direction
Authors: Hasegawa Koji , Koshiba Masanori
Published: August 2002

The finite‐element analysis method based on the hybrid variational principle is proposed for analysis of the dispersion characteristic of periodic surface acoustic waveguides with a one‐wavelength period. A new formulation is used for finite element approximation applied to the periodic function part of Floquet modes. This approach allows elimination of the uniform field without sinusoidal variations in the periodic direction, which has been included in the conventional hybrid finite‐element analysis to directly approximate the entire field distribution. Hence, an analysis of periodic waveguide structures with a one‐wavelength period is now possible. Specifically, the reflection properties are studied for a metallic grating reflector with a one‐wavelength period formed on an X‐112°Y LiTaO3 substrate and for a DART and an EWC‐SPUDT. Comparison of experimental values and numerical results confirms the validity and usefulness of the method. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 85(1): 31–40, 2002
Refractive Index Control of Polyimide by Synchrotron Radiation, and the Application to Fabrication of a Waveguide Grating
Authors: Kobayashi Junya , Ishii Tetsuyoshi , Maruo Yasuko , Tamamura Toshiaki
Published: August 2002

Synchrotron radiation alters the refractive index of fluorinated polyimide, and it is possible to adjust the refractive index to within 10–2 by varying the irradiation dose. The chemical condition of the polyimide after irradiation was investigated by XPS, and it was shown that the refractive index change was caused by decreasing molecular volume following separation of fluorine atoms. Using this refractive index controllability and the linearity of the synchrotron radiation, a method of fabrication of a waveguide diffraction grating using only synchrotron irradiation of a fluorinated polyimide optical waveguide through an X‐ray mask having a diffraction grating pattern was proposed. The waveguide diffraction grating fabricated by this method exhibited a reflectivity of 60% and a half‐value width of 0.25 nm. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 85(1): 59–66, 2002
Symmetric Mach‐Zehnder‐type all‐optical switches and ultrafast all‐optical signal processing
Authors: Tajima Kazuhito , Nakamura Shigeru , Ueno Yoshiyasu
Published: August 2002

Symmetric Mach‐Zehnder (SMZ) type all‐optical switches, namely, the SMZ, polarization‐discriminating SMZ (PD‐SMZ), and delayed interference signal wavelength converter (DISC), are described in detail. All of these all‐optical switches are characterized by push–pull operation and allow ultrafast switching not limited by the relaxation time of high‐efficiency nonlinear optical materials that are suitable for low‐power operations. They make possible a low‐chirp switching window of a quasi‐square type that is important in practice. Ultrafast all‐optical signal processing with an SMZ, namely, 168 → 10.5 Gbit/s error‐free DEMUX (using a hybrid‐integrated SMZ, HI‐SMZ), zero‐penalty optical signal pulse regeneration at 84 and 168 Gbit/s, and error‐free all‐optical wavelength conversion are reported. In experiments with pulse regeneration and wavelength conversion, the error rate is evaluated after DEMUX to 10.5 Gbit/s by HI‐SMZ because the signal light after signal processing has ultrahigh speed. © 2002 Scripta Technica, Electron Comm Jpn Pt 2, 85(2): 1–17, 2002
The influence of background carbon concentration on the transient enhanced diffusion of boron
Authors: Saito Tomoya , Xia Jianxin , Kim Ryangsu , Aoki Takenori , Furuta Yoshikazu , Kamakura Yoshinari , Kobayashi Hiroyuki , Taniguchi Kenji
Published: August 2002

We have observed transient enhanced diffusion (TED) in silicon substrates with boron doping superlattices and varying background carbon concentrations after ion implantation with silicon ions followed by low‐temperature annealing. Our results clarify the effects of low‐level carbon concentrations on this process. In addition, we have found that the effective diffusion coefficient of self‐interstitial Si atoms is inversely proportional to the square of the substrate carbon concentration. We also discovered that the carbon atoms segregate out in the ion‐implantation damage regions, forming boron–carbon clusters. © 2002 Scripta Technica, Electron Comm Jpn Pt 2, 85(2): 54–60, 2002
Reducing the numerical dispersion in the FDTD analysis by modifying the speed of light
Authors: Suzuki Kosuke , Kashiwa Tatsuya
Published: August 2002

In FDTD analysis, the numerical dispersion caused by the discretization of time and space becomes a problem. Previously, the numerical dispersion was corrected by changing the speed of light. However, such an approach is limited to isotropic meshes. In this paper, a generalized formulation is introduced such that this correction method can also be used in nonisotropic meshes. As an application example, the method is used for the analysis of a large cavity, demonstrating the effectiveness of the method. © 2002 Scripta Technica, Electron Comm Jpn Pt 2, 85(2): 61–69, 2002
A neural network combined two‐stage algorithm for route assignment problems with reliability satisfaction in multihop radio networks
Authors: Baba Takayuki , Funabiki Nobuo , Tajima Shigeto
Published: August 2002

The radio network is a large‐scale communication network in which a large number of stations are distributed over a wide area. Each station can communicate directly by radio packets only with neighborhood stations. Packet communication between stations which cannot communicate directly is realized by passing packets through multiple stations between them. For this purpose, when a packet communication request arises, the route for the packet and the transfer timing must be chosen so that the total transfer time is minimized and the efficiency of the radio network is maximized. It should be noted that the reliability, representing the probability that the required performance is achieved, fluctuates among the stations in the network due to the differences in the time of installation, the designed performance, and communication congestion. Consequently, this paper proposes a two‐stage algorithm in which the route is assigned so that its reliability is larger than the required value. The proposed algorithm is composed of the iterative reliability satisfaction extraction procedure, in which a set of path candidates satisfying the reliability condition for the given transfer request, and the greedy neural network procedure, in which the route minimizing the cost is selected from the set of path candidates. The effectiveness of the proposed algorithm is demonstrated by simulation for networks with up to 500 stations. © 2002 Scripta Technica, Electron Comm Jpn Pt 3, 85(6): 63–73, 2002
Design of stabilized laser for optically pumped atomic frequency standards
Authors: Hisadome Kenji , Kihara Masami
Published: August 2002

The influence of a stabilized laser's fluctuations in an optically pumped atomic frequency standard is considered. It is important to use a laser with narrow linewidth and select the modulation frequency where the laser's free‐running frequency fluctuation at twice the modulation frequency is the lowest. Employing these considerations, the stabilized laser for our optically pumped cesium beam frequency standard is designed. © 2001 Scripta Technica, Electr Eng Jpn, 136(2): 31–37, 2001
Equivalent circuit and characteristics of an induction motor with reduced turns of terminal coils
Authors: Hitosugi Kazuyoshi , Moriyasu Shoji , Nanba Noriyuki
Published: August 2002

The use of a PWM inverter with high switching characteristic for adjustable speed drive systems causes an overvoltage with steep‐fronted waveform on the motor terminals. Since this steep‐fronted transient voltage in an inverter drive heavily loads the terminal coils of the motor winding, insulation failure in the motor winding occurs mostly in the terminal coils. Therefore, it is reasonable to reduce the turns of only the terminal coils and to increase the dielectric strength of the interturn insulation.

This describes an equivalent circuit taking the space harmonic into account and discusses the starting and operating characteristics of the induction motor with reduced turns of the terminal coils. © 2001 Scripta Technica, Electr Eng Jpn, 137(4): 64–75, 2001
Life cycle CO2 emissions of a photovoltaic/wind/diesel generating system
Authors: Kemmoku Yoshishige , Ishikawa Keiko , Nakagawa Shigeyasu , Kawamoto Teru , Sakakibara Tateki
Published: August 2002

A photovoltaic/wind/diesel generating system with a battery (PWD system) is discussed from the viewpoint of total CO2 gas emissions during system lifetime. The total emissions are the sum of the emissions occurring at manufacturing and operating. First, the manufacturing CO2 emissions of the photovoltaic generator and the wind turbine generator are calculated by “the process analysis method.” This method considers the material used in each generator, its weight and its CO2 emission rate. On the other hand, the manufacturing CO2 emissions of the diesel generator and the battery are calculated using “the interindustry (input‐output) table.” Second, the PWD system is operated on a computer so that the fuel consumption of the diesel generator is a minimum assuming that hourly series data of electric load, insolation intensity, wind speed, and air temperature are known during the year. And CO2 emissions occurring at system operation are obtained from the annual fuel consumption of the diesel generator.

The results show that CO2 total emissions of the PWD system are lower than those of the conventional diesel generator system. The CO2 total emissions reach a minimum when the photovoltaic/wind generating ratio is 50/50. The CO2 emissions of manufacturing decrease with increasing of the wind generating ratio from 100/0 to 0/100. The CO2 total emissions decrease as the natural energy ratio increases. It is, however, saturated to about 60% when the ratio is more than 60%. And the CO2 total emissions increase with increasing of the battery capacity. It is concluded that the PWD system plays an important role in decreasing considerably the CO2 total emissions while the total system cost is high under the present price circumstances. © 2001 Scripta Technica, Electr Eng Jpn, 138(2): 14–23, 2002
Multidimensional binary search calculation of the neuron model
Authors: Chujo Naoya , Kuroyanagi Susumu , Doki Shinji , Okuma Shigeru
Published: August 2002

Artificial neural networks have the potential for parallel processing with integrated circuit technology. Over 1 million gates are now available in the latest FPGA (Field Programmable Gate Array). However, the sum‐of‐product circuit used for evaluating inputs of the neuron model is complex and not effective for hardware implementation by FPGAs. In this paper, an improved calculation algorithm of the perceptron‐type neuron model is proposed, based on multidimensional binary search. Since the search does not need the sum‐of‐product circuit, the designed neuron circuit is small and fast. It is suitable for hardware implementation. © 2001 Scripta Technica, Electr Eng Jpn, 138(2): 24–32, 2002
Dual mode synchronous positioning with switching of master–slave axes by using a torque signal for contour control of articulated robot arms
Authors: Nakamura Masatoshi , Yamanaka Shinji , Goto Satoru , Kyura Nobuhiro
Published: August 2002

Dual mode synchronous positioning control with switching of master and slave axes is proposed to realize accurate contour control of industrial robot arms. The axis which is contaminated with disturbance is selected as the master axis, then the disturbances in both first axis and second axis can be compensated. The effectiveness of the proposed method was verified by experimental results of an actual articulated robot arm. © 2001 Scripta Technica, Electr Eng Jpn, 138(2): 33–40, 2002
A load dispatch method using fractional programming and semidefinite programming
Authors: Kobayashi Yasuhiro , Sawa Toshiyuki , Furukawa Toshiyuki , Kawamoto Shigeru
Published: August 2002

This paper describes a load dispatch method which minimizes power cost—[fuel cost]/[electric output]—for a power system with thermal plants and energy storage facilities. The proposed method employs fractional programming to convert a minimization problem with fractional objective function to a series of quadratic minimization problems, and semidefinite programming to solve converted problems. The method provides the optimum time‐dependent power output/input and storage level of energy storage facilities as well as time‐dependent power output of thermal plants.

The method has been applied to a power system with five thermal plants, two energy storage facilities of various performances, and five load demands. The optimum load scheme of four time mesh points is obtained for the thermal plants and energy storage facilities. The fractional programming successfully converges the optimal scheme through a few iterations. The semidefinite programming deals with a variable matrix of 164 dimensions, and 185 inequality constraints. © 2001 Scripta Technica, Electr Eng Jpn, 138(2): 49–58, 2002
A harmonic compensation brushless synchronous condenser using a cascade induction machine
Authors: Fukami Tadashi , Ishii Naoto
Published: August 2002

In this paper, a new brushless synchronous condenser termed the BSC‐Filter is presented. It consists of two wound‐rotor induction machines connected in a cascade, and acts not only as a synchronous condenser but also as a passive filter with a capacitor connected to its stator field winding. An equivalent circuit model seen from the sixth harmonic in the field system is illustrated using the method of symmetrical coordinates. Based on this equivalent circuit model, a fundamental formula is derived to select the capacitor value properly. The validity of the theoretical analysis is verified through experiments, and basic characteristics of the BSC‐Filter are clarified. In addition to phase compensation, this new machine is capable of reducing low‐order fifth and seventh harmonics in power lines. © 2001 Scripta Technica, Electr Eng Jpn, 138(2): 71–78, 2002
Fabrication and evaluation of LaCrO3 thin film heaters
Authors: Hayashi Shinichiro , Sofue Satoshi , Yoshikado Shinzo
Published: August 2002

Lanthanum chromium oxide (LaCrO3) has excellent high‐temperature properties. LaCrO3 doped with alkaline earth metals also has high electric conductivity. The purpose of this study is to fabricate thin film heaters using LaCrO3 doped with Ca by RF magnetron sputtering method. The crystal structure of thin films was evaluated and the surface form was studied. The results show that the thin film deposited on Si(100) single crystal and quartz glass substrates in Ar gas had a strong orientation and that its surface form was comparatively smooth. The crystal structure of the thin films deposited on Si(100) and quartz glass substrate at temperatures of 700 and 800 °C by sputtering in a mixture of Ar and O2 gases was the same as the crystal structure of LaCrO3. The heating characteristics of a thin film heater on Si(100) substrate with Pt electrodes were evaluated by measurement of the equilibrium temperature‐current (T–I) and resistance‐equilibrium temperature (R–T) characteristics. The maximum equilibrium heating temperature was about 1100 °C. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 139(3): 18–25, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.1156
Propagation and radiation field characteristics of nanometer electromagnetic waves in x‐ray dielectric waveguides with random media
Authors: Miyazaki Yasumitsu
Published: August 2002

X‐rays in the nanometer electromagnetic region are useful for nanospace fabrication, information and high‐energy transmission and control techniques of angstrom‐size structures in biomedical sciences and technology. In this paper, the electromagnetic fields in X‐ray gradient fiber with random refractive index media are studied. Statistical mode conversion of beam propagation, beam broadening, and beam center are investigated by the stochastic process theory of electromagnetic fields. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 139(3): 53–61, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.10002/eej.1160
Environmental indicators of transition
Authors: Ichikawa Nobuko , Tsutsumi Rie , Watanabe Kohei
Published: August 2002

This paper uses a range of environmental indicators in order to assess the progress being made in addressing environmental transition challenges within the EBRD's 26 countries of operation. [In 2001, FR Yugoslavia joined the EBRD's member countries. As of February 2002, the EBRD's countries of operation are 27 countries.] The assessment is based on a survey carried out in summer 2000 among environment ministries in the region, which aimed to obtain information about economic/environmental interactions, environmental quality changes and developments in policy, institutional capacities and public participation. The paper evaluates the various national responses to the region's environmental problems. This includes an examination of environmental policy developments, frameworks for establishing environmental liability and systems of environmental funds. The final section looks at the development of public environmental initiatives and non‐governmental organizations. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment.
Greenhouse gas emission policies in the UK and Germany: influences and responses
Authors: Schrader Bettina
Published: August 2002

Climate change is considered to be one of the greatest environmental threats. In response to this threat, developed countries agreed in Kyoto to legally binding targets, which will reduce their atmospheric emissions. In April 1999 Germany introduced an environmental tax. At the same time the UK announced the introduction of a levy on energy consumption, from April 2001. This paper investigates the proposals from both governments and the influences upon them of a variety of institutions (NGOs, industry and business organizations). The similarities and differences between the consultation experiences, and the resulting policies, will be discussed for the two countries. Lessons are drawn applicable to the wider context of EU environmental legislation. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment
Crossed categorization effects on the formation of illusory correlations
Authors: Meiser Thorsten , Hewstone Miles
Published: August 2002

This study investigates how stereotypes are formed and whether stereotype formation is reduced by the prevalence of multiple categorizations. Illusory correlations between the desirability of behaviours and two dimensions of social categorization, both containing a majority and a minority category, were assessed in single categorization and crossed categorization conditions. In the single categorization conditions, the usual illusory correlation in favour of the majority category was obtained. In the crossed condition, the combination of the two majority categories was positively discriminated from the remaining three combinations, while no differences were found among the latter. A source‐monitoring analysis of assignment frequencies replicated earlier findings that illusory correlations are due to an evaluative guessing bias, rather than to enhanced memory for individual instances of behaviour. The results show inconsistencies with a distinctiveness‐based and a social categorization account of illusory correlations, but they can be explained in terms of information loss. Copyright © 2001 John Wiley & Sons, Ltd.
Challenge and threat responses during downward and upward social comparisons
Authors: Mendes Wendy Berry , Blascovich Jim , Major Brenda , Seery Mark
Published: August 2002

We examined cardiovascular responses indicating challenge and threat during social comparisons. Experiment 1 manipulated comparison direction (i.e. upward/downward) within a cooperative social interaction, during which we measured cardiovascular responses, evaluations of demands and resources, and self‐reports. Participants interacting with upward comparison partners evaluated the task as more ‘threatening’ (demands relative to resources) than participants cooperating with downward comparison partners. Moreover, participants cooperating with upward comparison partners exhibited cardiovascular reactivity consistent with threat (i.e. increased ventricle contractility, no changes in cardiac output, and vasoconstriction). In contrast, participants interacting with downward comparison partners exhibited challenge responses (i.e. increased contractility, increased cardiac output, and vasodilation). This basic finding was extended in Experiment 2 with the examination of a classic moderator of social comparison, attitudinal similarity of the comparison partner. Participants paired with attitudinally dissimilar partners exhibited exacerbated reactions relative to participants paired with attitudinally similar partners. That is, relative to similar partners, dissimilar partners engendered greater threat responses during upward comparisons and a tendency toward greater challenge responses during downward comparisons. These results are discussed within an assimilative/contrast model of social comparisons. Copyright © 2001 John Wiley & Sons, Ltd.
Frequencies and relative levels of clustered damages in DNA exposed to gamma rays in radioquenching vs. nonradioquenching conditions
Authors: Sutherland Betsy M. , Bennett Paula V. , Weinert Emily , Sidorkina Olga , Laval Jacques
Published: August 2002

Clustered damage induced by ionizing radiation—two or more oxidized bases, abasic sites, or strand breaks within a few DNA helical turns—have been postulated to be major lethal and/or mutagenic sites. Although they have recently been shown to be induced in genomic DNAs by ionizing photons and particles, little is known of the factors that affect their yields or the relative levels of the classes of clusters. Toward this aim we have investigated the effect of DNA milieu, specifically, a nonradioquenching (phosphate) or radioquenching (Tris) solution, upon the generation of clustered lesions in a well‐defined molecule, T7 bacteriophage DNA. Irradiation of DNA in Tris reduces the yields of all clustered damages to 1–3% of the levels formed in phosphate. Further, although the percentage of the total clusters in oxidized purine clusters is largely unchanged, and the level of abasic clusters decreases, the frequencies of double‐strand breaks and oxidized pyrimidine clusters increase in the radioquenching solution. The ratio of the level of oxidized pyrimidine clusters to double‐strand breaks in a DNA in radioquenching solution is similar to that obtained in DNA in human cells, also a radioquenching environment. Environ. Mol. Mutagen. 38:159–165, 2001. Published 2001 Wiley‐Liss, Inc.
Assessing the communication of environmental policies: a chaotic model
Authors: Winnard G.M. , Cannibal G.L.
Published: August 2002

There is nothing more difficult to carry out, nor more doubtful of success,
nor more dangerous to handle, than to initiate a new order of things.
Machiavelli.

This study assessed the communication methods used to promote energy reduction within a city council, and suggested ways of improving them. These methods were assessed using Lichtenstein's chaotic logic of organizational transformation, which uses chaos theory to divide a cultural change process into three stages. The council was identified as not having completed stage one of that change process, which involves the identification of reasons as to why a change process is necessary, and communicating about the change process to everybody in the entire organization. This was judged to be because the organization‐wide formal and informal communication network necessary for efficient cultural change had not been built. In order to improve the efficiency of communication, education and training methods, recommendations were made that included a council‐wide survey around energy issues, a series of informal meetings and the utilization of peer pressure and formal, informal, qualitative and quantitative feedback. Copyright © 2001 John Wiley & Sons, Ltd and ERP Environment
Assessing the biotic distance between groups of biological populations by means of replicated counts
Authors: Marcheselli M.
Published: August 2002

The problem of assessing the difference in species composition between groups of biological populations is considered when the vectors of relative abundances are estimated through replicated counts. A Monte Carlo study was employed to investigate the performance of classical MANOVA and Smith's permutation test. The use of MANOVA represents a promising strategy provided that an adequate number of populations is assigned to those groups in which a greater variability of abundance estimates arises. Copyright © 2002 John Wiley & Sons, Ltd.
Gray box identification of flexible structures: application to robust active vibration suppression control
Authors: Forrai A. , Hashimoto S. , Isojima A. , Funato H. , Kamiyama K.
Published: August 2002

The paper deals with gray box identification of flexible structures and active vibration suppression from a robust control perspective. First, the linearized mathematical model of an N‐storey flexible structure is presented. Next, the generalized mathematical model is particularized for the investigated three‐storey flexible structure. The considered flexible structure is identified based on black box and gray box identification methods and the model's parametric uncertainties are deduced. Furthermore, control constraints are presented for the design problem, in case of velocity as well as acceleration feedback, from a robust control perspective. Finally, the effectiveness of the control system is tested through experiments, when the input disturbance is assumed to be a sinusoidal one as well as a historical earthquake record (1940 El Centro record). Copyright © 2001 John Wiley & Sons, Ltd.
Influence of reed stem density on foredune development
Authors: Arens S. M. , Baas A. C. W. , Van Boxel J. H. , Kalkman C.
Published: August 2002

Vegetation density on foredunes exerts an important control on aeolian sediment transport and deposition, and therefore on profile development. In a long‐term monitoring field experiment, three plots were planted with regular grids of reed bundles in three different densities: 4, 2 and 1 bundles per m2. This study reports on the differences in profile development under the range of vegetation densities.

Topographic profiles were measured between May 1996 and April 1997. Results indicate important differences in profile development for the three reed bundle densities: in the highest density plot a distinct, steep dune developed, while in the lowest density a more gradual and smooth sand ramp was deposited. When the stems had been completely buried, differences in profile evolution vanished. After a second planting of reed stems in January 1997 the process was repeated. In May 1997, all plots had gained a sand volume ranging from 11·5 to 12·3 m3 m−1, indicating that the sediment budget is relatively constant, regardless of the particular profile evolution.

The field evidence is compared with simulations of profile development, generated by the foredune development model SAFE. The model successfully reproduces the overall profile development, but in general, the equations used for vegetation–transport interaction overestimate the effect of vegetation. This causes some deviations between field and model results. Several reasons for this are discussed. Based on the experiments reported here, recommendations are given for further research. Copyright © 2001 John Wiley & Sons, Ltd.
Assessment of shallow landslide susceptibility by means of multivariate statistical techniques
Authors: Baeza Cristina , Corominas Jordi
Published: August 2002

Several multivariate statistical analyses have been performed to identify the most influential geological and geomorphological parameters on shallow landsliding and to quantify their relative contribution. A data set was first prepared including more than 30 attributes of 230 failed and unfailed slopes. The performance of principal component analysis, t‐test and one‐way test, allowed a preliminary selection of the most significant variables, which were used as input variables for the discriminant analysis. The function obtained has classified successfully 88·5 per cent of the overall slope population and 95·6 per cent of the failed slopes. Slope gradient, watershed area and land‐use appeared as the most powerful discriminant factors. A landslide susceptibility map, based on the scores of the discriminant function, has been prepared for Ensija range in the Eastern Pyrenees. An index of relative landslide density shows that the results of the map are consistent. Copyright © 2001 John Wiley & Sons, Ltd.
Use of the mass spectrometer for heat release rate analysis in fire calorimeters
Authors: Enright P.A. (Tony) , Vandevelde Paul
Published: August 2002

This document outlines the concept of replacing the conventional gas analysis train in fire calorimeters, with a mass spectrometer (MS). This concept is motivated by a desire to improve upon aspects of the conventional technique. These are cumbersome equations, time delays, time lags and ‘noisy’ results. The theoretical advantages and disadvantages of using a MS are presented. This document should form the basis of an experimental programme to value the worth of the concept. Copyright © 2002 John Wiley & Sons, Ltd.
The fire performance of electrical insulating materials used in fluorescent lighting fixtures
Authors: Zicherman Joseph
Published: August 2002

Analysis of a major fire incident at a home furnishings warehouse led to the conclusion that extended exposure of electrical insulating materials composing a lampholder in a fluorescent lamp were the initial items ignited. It was thought that these items, composed of thermoset polymers, were ignition‐resistant materials. However, analysis showed that thermally induced degradation caused the material to degrade into an easily ignited, char‐like residue. The parent polymer, highly cross‐linked urea formaldehyde, had been initially cast into the lampholder configuration to prevent high voltage conditions and arcing.

Thermal and elemental analyses as well as the investigation conducted at the fire site, helped to determine that the original polymer had pyrolysed into a residue differing in both chemical composition — reduced hydrogen and oxygen content — and physical characteristics when compared with the parent material. The changes in the chemical and physical properties of the original polymer explain the observed thermal inertia of the residue and its tendency to smolder (as opposed to the ‘parent polymer’). They are characterized by (1) an increased accessibility to oxygen, (2) reduced thermal conductivity and (3) increased proportion of carbon. Copyright © 2002 John Wiley & Sons, Ltd.