bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conditions of half‐frequency oscillation in high‐power amplifier with FET and its suppression method using quarter‐wavelength open‐circuited stub
Authors: Uchida Hiromitsu , Itoh Yasushi , Miyazaki Moriyasu , Urasaki Shuji 
Published: October 2002

AbstractWith regard to the half‐frequency oscillation observed in the nonlinear operation of a microwave power amplifier based on FETs, the voltage and current of the FET in a large‐signal mode at an excitation frequency of 2f0 are expanded as Fourier series in half this frequency, that is, f0. Then, the condition that the Fourier coefficient for the f0 component is nonzero, namely, the condition of half‐frequency oscillation, is derived. It is shown that the half‐frequency oscillation takes place when the determinant is zero for the matrix defined by the fundamental excitation components and time averages of the gate‐to‐source capacitance, mutual conductance, and drain conductance, as well as the load impedance condition at frequency f0. Also, a method for suppression of the half‐frequency oscillation by connecting an open stub one‐quarter wavelength long at the half‐frequency to the output side of the FET is proposed, and its effectiveness is confirmed by experiment. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(6): 11–19, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10008
Two‐dimensional parallel optical interconnect module formation based on microoptical bench concept
Authors: Aoki Yasuhiko , Shimada Yuji , Koyama Fumio , Iga Kenichi 
Published: October 2002

AbstractParallel optical interconnect technology is arousing high hopes for applications to very short reaches between optical communication transmission devices and to interconnection between high‐speed computers. However, no sufficient study has been carried out on the integration technology for two‐dimensional array‐type optical components, which are indispensable for large‐scale integration of the optical components used for parallel optical interconnects. This paper presents a method of integration of parallel optical components, using the microoptical bench (MOB) proposed by the authors as an integration technique for two‐dimensional array‐type optical components, together with characteristic evaluation of the planar microlens, as the key component, and an extension of the parallel optical interconnect module using wavelength division multiplexing. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(7): 30–36, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10027
Realizing eye movement in reading
Authors: Ishihara Yukio , Morita Satoru 
Published: October 2002

AbstractA feature of human viewpoint movement in reading English has been pointed out from the psychological aspect, namely, that the first viewpoint on the word concentrates at the center of the word. This paper focuses on the three factors that seem to induce the above feature of viewpoint movement in reading English, which are the use of foveal vision, the use of the edge density of letters (characters), and the use of the space between words. The movement of the viewpoint is realized on a computer, and the major factor responsible for the feature that the viewpoint concentrates at the center of the word is examined. The attention region is defined in realizing viewpoint movement that is restricted. The viewpoint is actually moved for the cases where each of the three factors is followed or not followed, and the features of viewpoint movement are examined. The features of viewpoint movement realized on the basis of each factor are compared to those of previously reported human viewpoint movement. Based on the comparison, it is shown that the three factors are actually inducing the feature that the viewpoint concentrates at the center of the word. By varying the size of the attention region, the effect on the viewpoint movement is examined, and it is shown that the size of the attention region is the factor that manifests the features of human viewpoint movement. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(8): 34–43, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10064
The effect of an externally applied radio‐frequency electromagnetic field on the performance of a disk MHD generator
Authors: Fujino Takayasu , Watanabe Yukihiro , Okuno Yoshihiro , Yamasaki Hiroyuki 
Published: October 2002

AbstractThe effects of an externally applied radio‐frequency (rf) electromagnetic field on the nonequilibrium performance of a disk MHD generator were examined experimentally. As a preliminary experiment, plasma production by the applied rf electromagnetic field was attempted in the disk generator (Disk‐PIA), in which rf induction coils were embedded in the one‐side disk wall, under the conditions of no seeding, no flow, and no magnetic field. From the results of the preliminary experiment, it was confirmed that the argon plasma (∼110 Torr) was produced uniformly in the azimuthal direction by the rf electromagnetic field even in the presence of exposed anodes in the faced disk wall and metallic support at the disk center. In MHD power generation experiments with the Disk‐PIA installed in the shock‐tube facility, the increase in the electrical output and more indiscrete discharge attributed to the rf electromagnetic field were verified with good reproducibility for the first time. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(4): 46–53, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10009
Quantitative analysis of the influence of conductors and ferromagnetic structures in power facilities on an ELF magnetic field environment using the finite element method
Authors: Kato Katsuji , Goto Naoki , Uga Yuji , Shimizu Masaji , Yoshida Akio , Okubo Hiroshi 
Published: October 2002

AbstractRecently, electric power transmission/substation systems need to be extended and they tend to be more compact. From the backgrounds of electromagnetic field environment, especially the magnetic field environment in and around electric power facilities becomes more important. However, many factors must be considered when investigating it, such as complicated current conditions, configurations of conductors and ferromagnetic structures, and so on. For more precise investigation of magnetic field environments, we must understand the quantitative influence of conductors and ferromagnetic structures.In this paper we describe how conductive and ferromagnetic materials influence the ELF magnetic field distribution. We carried out the measurement and finite element analysis of magnetic flux density distribution around an aluminum plate, a soft magnetic iron plate, and a 1/40 reduced model of an actual transmission tower. Based on the results, we clarified the influence of conductors and ferromagnetic substances on the magnetic flux density distribution around them. Finally, we showed the effectiveness of finite element analysis for evaluating the magnetic field around actual power facilities. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(3): 44–52, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10021
A transmission line fault‐location system using the wavelet transform
Authors: Hisakado Takashi , Tanaka Kohji , Okumura Kohshi 
Published: October 2002

AbstractThis paper describes the locating system of line‐to‐ground faults on a transmission line by wavelet transform. The possibility of the location with the surge generated by a fault has been theoretically proposed. In order to make the method practicable, we realize very fast processors. We design wavelet transform and location chips, and construct a very fast fault location system by processing the measured data in parallel. This system is realized by a computer with three FPGA processor boards on a PCI bus. The processors are controlled by UNIX and the system has the graphic user interface with X window system. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(4): 27–37, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10040
Improvement of performance of disk MHD generator with argon by introduction of swirl
Authors: Torii Syunsuke , Tsutsumi Masashi , Okuno Yoshihiro , Yamasaki Hiroyuki 
Published: October 2002

AbstractAn experimental study of performance of the disk MHD generator with argon was carried out using a shock‐tube driven facility. An inlet swirl was introduced in the MHD channel in order to improve the enthalpy extraction and the isentropic efficiency. The experimental results were compared with those of the disk MHD generator without the inlet swirl. A high enthalpy extraction of 25.7% was obtained and the highest isentropic efficiency for argon was achieved at the same time in the present experiment. The measured static pressure in the MHD channel was kept lower than that without the inlet swirl. This has suggested that the introduction of the inlet swirl reduces the retarding force for the flow and that the increase of the enthalpy extraction is ascribed to the increase of the flow velocity and of the electrical efficiency. Furthermore, the flow without shock wave was observed at low seed fractions and low load resistances. At the same time, it was found for the first time that when there was no shock wave, the isentropic efficiency became higher than that with the shock wave. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(1): 18–25, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10045
Performance evaluation of continuous levitation in an active‐maglev system using YBCO bulk and multiple electromagnets
Authors: Ueda Hiroshi , Hayashi Hiroki , Ishiyama Atsushi , Tsuda Makoto 
Published: October 2002

AbstractWe have designed and constructed a new type of active‐maglev system using YBCO bulk and two electromagnets and have demonstrated that levitation height was remarkably improved by continuous levitation. In the active‐maglev system, however, the upper and lower coils differed in the coil size and an iron plate beneath the lower coil was used to enhance the magnetic field around the bulk. Considering the real application to maglev transporter in the axial direction, we must realize continuous leviation using a larger number of electromagnets without such iron plate and enable the levitation height to be controlled freely. In this paper, we demonstrate continuous levitation while controlling the leviation height using three‐ and five‐electromagnet systems and investigate electromagnetic behavior within the bulk using an FEM computer program. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(2): 25–33, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10055
A multi‐agent approach to unit commitment
Authors: Nagata Takeshi , Ohno Masumi , Sasaki Hiroshi , Fujita Hideki 
Published: October 2002

AbstractThis paper proposes a multiagent system to power system unit commitment problems. Multiagent is a new paradigm for developing software applications. Coordinating the behavior of autonomous agents is a key issue in agent‐oriented programming techniques today. Recently, agents are being used in an increasingly wide variety of applications, ranging from comparatively small systems such as E‐mail filters to large, open, complex systems such as air traffic control. Though some agent frameworks have been proposed in the power system field, the number of studies is limited.In this paper, we developed a power system unit commitment application by multiagent architecture. Our multiagent system has the following characteristics: (1) The system consists of a single facilitator agent, two mobile agents, and one or more generator agents which are elements of power system network. (2) The facilitator agent is developed to act as a manager for the process by using the singleton design pattern. The mobile agents migrate to generator‐agents to increase or decrease their power generations. The generator agents have their operational data. (3) Message object is developed to communicate between the agents using KQML‐like object. The proposed approach is applied to a simple model system, and the results show that the multiagent system is an efficient decentralized approach for solving power system unit commitment problems. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(2): 41–47, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10057
Development of TCSC application to fault current limiters
Authors: Yamazaki Yuji , Sugimoto Shigeyuki , Ogawa Shigeaki , Konishi Hiroo , Kikuchi Akira 
Published: October 2002

AbstractA new Fault Current Limiter (FCL) is proposed which consists of a conventional Current Limiting Reactor (CLR) and a Thyristor‐Controlled Series Compensator (TCSC) in series. In normal operation, it works to compensate for impedance of the CLR and a line, while it limits short‐circuit currents during system faults. After the fault clearance, it damps power oscillations. Effectiveness of fault current suppression and damping effects on power system oscillations were studied by digital simulations and by an analogue simulator. It was found that the proposed FCL could decrease impedance of a conventional CLR reactor due to inductive impedance of the TCSC and have good damping characteristics. From investigation of cooperative protection system for the FCL, it showed that fast bypasses of the thyristors in the TCSC were useful for overvoltage protection, fault current limit and decrease in capacity of protective arresters connected in parallel with the TCSC. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(3): 53–60, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.2004
Climate protection through tradable permits: the EU proposal for a CO2 emissions trading system in Europe
Authors: Gagelmann Frank , Hansjürgens Bernd 
Published: October 2002

AbstractOn 23 October 2001 the European Commission adopted a proposal for a directive for trade in greenhouse gas emissions. Following the US experience of emissions trading systems, this marks the first large‐scale attempt to deploy this instrument of environmental policy in Europe. The proposal places European climate protection policy on a completely new footing. The prospects of its implementation have increased since the climate change conference in Marrakech.This paper introduces the draft directive and gives an initial economic appraisal. It concludes that the directive deliberately—and wisely—limits the scope of the first trading phase, starting in 2005. Consequently, there is still considerable scope for increasing its efficiency (resulting from gains from trading) in later phases, namely by extending both the number of participants and the gases included. The number of participants in the first phase and the institutional arrangements, however, appear sufficient to enable a liquid, functioning market. In this respect, the (politically difficult) decision to start with a compulsory system is also to be welcomed.Important issues not yet sufficiently clarified include the concrete rules for defining the total permit quantity issued to participants by each member state, and whether other economic sectors, which are to be treated by ‘other policies and measures’, will bear a comparable burden. Furthermore, the essential questions of primary allocation and treatment of newcomers—which are in principle left up to member states—as well as the linkage of emissions trading with existing policies affecting the participating sectors must be solved before legal implementation is recommended. Copyright © 2002 John Wiley & Sons, Ltd and ERP Environment.
The developmental approach to young children's strategic social cognition and behaviour
Authors: Leonova Tamara , Dubois Nicole 
Published: October 2002

AbstractThis study explores the development of strategic behaviour related to kindness and intelligence dimensions in 3‐ to 8‐year‐old children. Previous research systematically highlighted the affective bias that limited young children's thinking and behaving in strategic terms. We argue that young children are able to grasp specific dimensions of social affordances from personality traits and behaviour exemplifying these traits. The results obtained in the partner choice paradigm revealed a developmental increase in social utility understanding. This supports our hypothesis of early social affordances understanding and provides empirical evidence that affective bias did not drastically influence strategic partner choice in 4‐ to 8‐year‐old children. Copyright © 2002 John Wiley & Sons, Ltd.
Aroclor 1254 alters morphology, survival, and gene expression in Xenopus laevis tadpoles
Authors: Jelaso Anna M. , Lehigh‐Shirey Elisabeth , Predenkiewicz Amy , Means Jay , Ide Charles F. 
Published: October 2002

AbstractPCBs are persistent environmental contaminants that cause a variety of adverse health effects in wildlife and humans. This article describes the use of signature gene expression patterns that link increased PCB exposure with progressive, adverse biological effects. Developing Xenopus laevis tadpoles of two age classes were exposed to the PCB mixture Aroclor 1254 for 2 days. Real‐time PCR was used to quantitate mRNA expression for 11 physiologically relevant, potential bioindicator genes. Younger tadpoles (5 days postfertilization) were resistant to Aroclor 1254 and showed few changes in gross morphology, swimming behavior, survival, or gene expression. Older tadpoles (11 days postfertilization) were more susceptible to Aroclor 1254. Exposure to 25 and 50 ppm Aroclor 1254 caused alterations in gross morphology and swimming behavior and statistically significant decreases in survival. These tadpoles showed statistically significant decreases in gene expression for 9 out of the 11 genes measured. Tadpoles exposed to 10 ppm showed incipient health changes but had gene expression profiles similar to the tadpoles treated with higher doses of Aroclor 1254. Tadpoles exposed to 1 ppm did not exhibit any observable adverse health effects, yet statistically significant decreases in gene expression occurred in these tadpoles (4 out of 11 genes). After prolonged exposure, tadpoles exposed to 1 and 10 ppm Aroclor 1254 exhibited health effects similar to those exposed to higher concentrations. Therefore, changes in expression of specific genes may serve not only as molecular bioindicators of Aroclor 1254 exposure but also as predictors of impending adverse health effects. Environ. Mol. Mutagen. 40:24–35, 2002. © 2002 Wiley‐Liss, Inc.
Determination of mechanical properties of traditional masonry walls in dwellings of Faial Island, Azores
Authors: Costa Aníbal 
Published: October 2002

AbstractThe determination of mechanical properties of masonry walls is a fundamental pre‐requisite for the characterization of the seismic response of traditional buildings, which helps on the definition of adequate rehabilitation and strengthening procedures.This paper presents a testing campaign carried out in the Cedros region of Faial Island, Azores, hit by the July 98 earthquake, aiming at the determination of physical and mechanical properties of stone masonry walls, namely the mass density and Young's modulus.The paper describes the developed testing techniques as a contribution to the study and the preservation of traditional masonry buildings. Copyright © 2002 John Wiley & Sons, Ltd.
Probabilistic analysis of peak response of MDOF systems with uncertain PSD function
Authors: Hong H. P. , Wang S. S. 
Published: October 2002

AbstractThe use of uniform hazard spectra which have the same probability of exceedance at different frequencies has been proposed for the future version of the National Building Code of Canada. Commonly used combination rules to estimate the peak responses of multi‐degree‐of‐freedom (MDOF) systems are the square root of sum of squares rule and the complete quadratic combination rule. However, the probability that the peak response of a MDOF system exceeds the one estimated by using these rules with the peak modal responses from the uniform hazard spectra cannot be inferred directly. The assessment of the probability of exceedance of the peak response of MDOF systems is presented by considering that the uncertainty in seismic excitation due to all potential earthquakes can be lumped in the power spectral density function of the ground acceleration with uncertain model parameters. This probability is evaluated based on the random vibration of linear systems and the first‐order reliability method. It is found that the under‐ or over‐estimations are less than about 5 or 10% if the modal contributions are not within 10–90% of, or not within 20–80% of, the absolute sum of the effective modal peak responses, respectively. Otherwise, severe under‐ or over‐estimation could result. Copyright © 2002 John Wiley & Sons, Ltd.
Geological controls on the formation of alluvial meanders and floodplain wetlands: the example of the Klip River, eastern Free State, South Africa
Authors: Tooth S. , McCarthy T. S. , Brandt D. , Hancox P. J. , Morris R. 
Published: October 2002

AbstractFloodplain wetlands are common features of rivers in southern Africa, but they have been little studied from a geological or geomorphological perspective. Study of the upper Klip River, eastern Free State, South Africa, indicates strong geological controls on the formation of alluvial meanders and associated floodplain wetlands. Along this river, pronounced and abrupt changes in valley width are strongly linked to lithological variations. Where weakly cemented sandstone crops out, the Klip has laterally eroded bedrock and carved valleys up to 1500 m wide. In these valleys, the river meanders (sinuosity up to ∼1·75) on moderate gradients (<0·001) within extensive floodplains marked by numerous oxbow lakes, backswamps and abandoned channels, many of which host substantial wetlands. In contrast, where highly resistant dolerite crops out, lateral erosion of bedrock is restricted, with the Klip tending instead to erode vertically along joints or fractures. Here, valleys are narrower (<200 m), channel‐bed gradients are steeper (>0·003), the river follows a much straighter course (sinuosity ∼1·10–1·34), and floodplains are restricted in width.Long‐term landscape development in the Klip and numerous similar catchments depends on the interaction between fluvial processes in the sandstone and dolerite valleys. In the sandstone valleys, vertical erosion rates are controlled by erosion rates of the more resistant dolerites downstream. Hence, in the short‐ to medium‐term (decades to tens of thousands of years), lateral erosion dominates over vertical erosion, with the river concomitantly planing sandstone in the channel floor and reworking floodplain sediments. The thickness of alluvial fill in the sandstone valleys is limited (<4 m), but the resultant meanders are naturally dynamic, with processes such as point bar deposition, cutoff formation and channel avulsion resulting in an assemblage of fluvial landforms. In the longer term (greater than tens of thousands of years), however, vertical erosion will occur in the sandstone valleys as the downstream dolerites are lowered by erosion, resulting in channel incision, floodplain abandonment, and desiccation of the wetlands. Identification of the geological controls on meander and wetland formation provides information vital for the design of effective management guidelines for these ecologically rich habitats, and also contributes to a better understanding of rivers that are intermediate between fully alluvial and fully bedrock. Copyright © 2002 John Wiley & Sons, Ltd.