bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inverse scattering method for one‐dimensional inhomogeneous lossy medium using linear prediction method
Authors: Watanabe Hideaki , Uehara Yoshiyuki , Noguchi Akira 
Published: July 2007

AbstractA method of solution based on a linear prediction method is presented for an inverse scattering problem in which the permittivity ε(x) and the conductivity s̀(x) in a one‐dimensional inhomogeneous lossy material are estimated from the reflected and transmitted waves. The present method is shown in the following manner. First, from Maxwell's equation governing the medium, coupled equations for the forward and backward waves are derived which subsequently are discretized. In the discretized coupled equations, the permittivity ε(x) and the conductivity s̀(x) are included as coupling potentials. Also, if these discretized coupled equations are used, the transmitted and reflected waves for the incident impulse are an AR and an ARMA process, respectively. Their AR and MA parameters are closely related to the coupling potentials. Hence, from the reflected and transmitted waves for the incident impulse, the permittivity and permeability of the medium can be determined via the coupling potentials. To confirm the validity of the forementioned method, several computer simulations have been carried out.
A high‐speed SRAM using BICMOS technology
Authors: Douseki Takakuni , Ohmori Yasuo 
Published: July 2007

AbstractTo realize a large‐capacity, high‐speed ECL‐compatible SRAM with an access time comparable to that of bipolar ECL RAMs, we have investigated a circuit configuration and optimizing method for SRAMs with peripheral circuits consisting of BiCMOS circuitry except for memory cells on the basis of submicron BiCMOS technology. A predecoder configuration with a bipolar small‐amplitude logic circuitry is proposed and the number of predecoders that minimizes the decoder power dissipation is determined. Also, a word‐driver circuit that utilizes an NMOS transistor as the driving transistor with BiCMOS inverters is proposed, and its highspeed operation is confirmed. Next, a multiplexer which selects a pair of bit‐lines by switching the pull‐up voltage with an NMOS transistor and drives data‐lines with emitter‐follower circuits is proposed and its high‐speed operation confirmed. Finally, an optimized memory cell array configuration that minimizes the delay time from the memory cell to the multiplexer is proposed.
Evaluation of mode‐field‐diameter definitions and conditions for single‐mode fibers by transmitted field pattern methods
Authors: Kuwaki Nobuo , Ohashi Masaharu , Tanaka Chihaya , Uesugi Naoshi 
Published: July 2007

AbstractThis paper investigates the relative effectiveness of three different definitions of mode‐field diameter in evaluation of splice losses of current and dispersion‐shifted fibers. As a result, it is shown that the difference in splice losses, due to various definitions, increases with decreasing V value. Further, it is confirmed theoretically and experimentally that by using Petermann's new definition, it is possible to estimate the splice loss very well. Next, using NFP and FFP methods, the measurement conditions of mode field diameter are also investigated. As a result, it is shown theoretically and experimentally that to keep the measurement error below 1 percent, it is necessary for the dynamic ranges of NFP and FFP methods to be larger than 25 and 35 dB, respectively. Under these conditions, it is shown that the measured results of both methods are in good agreement.
Elliptical micro‐fresnel lenses fabricated by electron‐beam writing technique
Authors: Shiono Teruhiro , Setsune Kentaro , Yamazaki Osamu 
Published: July 2007

AbstractElliptical micro‐Fresnel lenses can exhibit astigmatic characteristics; and hence, an astigmatic optical system made of a conventional combination lens can be made much thinner by their use. The authors have developed an electron‐beam writing system which has a function suitable for fabrication of thin‐film micro‐optical elements. The function of this writing system has been expanded so that elliptical micro‐Fresnel lenses can be fabricated. It has been confirmed that the fabricated lenses have a good sawtooth cross section. For the focusing characteristics of the lens, the eccentric ratios and the observation position dependence have been investigated theoretically and experimentally. The obtained focused spots almost reach the theoretical diffraction limit in both the major and minor directions. The intensity distribution of the focusing spots agree with the theoretical prediction. Hence, the fabricated lenses have focusing characteristics in agreement with the designed ones. Compared to the conventional microlens, these elliptical Fresnel lenses have a size smaller by one order of magnitude and their focusing efficiency is as high as 72 percent. Hence, it is expected that these lenses are new elements for micro‐optics.
Conduction mechanism of polycrystalline silicon thin‐film transistors
Authors: Saito Yoji , Abe Kazuhiko , Kawamoto Chinami , Kuwano Hiroshi 
Published: July 2007

AbstractThe drain current in polycrystalline silicon (polysilicon) TFTs (Thin Film Transistors) increases with increase of the gate voltage even if the polarity of the gate voltage is opposite to that of the drain voltage. This behavior is different from that in single‐crystal silicon MOSFET's. In this paper, to clarify the mechanism of this drain current, the dependence of the reverse bias current of polysilicon p+in+ diode with an MOS gate on voltage and temperature is examined. As a result, it is found that the mechanism of this current is Poole‐Frenkel current. Moreover, a simple model to explain the voltage and temperature dependence of this drain current is proposed, and its propriety is shown.
Relation between the loading characteristics and the mutual synchronization characteristics of microwave oscillators
Authors: Fukumoto Katsumi , Nakajima Masamitsu 
Published: July 2007

AbstractThe mutual synchronization characteristics at microwave frequencies have been studied from a practical viewpoint to combine the outputs from several oscillators and obtain a high power. However, in most of the studies, Van der Pol oscillators are used as a model of the oscillator. It is well known that the experimental results of the injection locking characteristics of Van der Pol oscillators cannot be predicted accurately as the injection signal becomes larger. In the previous report, an oscillator model was proposed with which the load characteristics of the microwave oscillator are expressed much more accurately. It was demonstrated that the analysis on the injection locking characteristics based on this model agree well with experimental data. In this paper, a new oscillator model is used and a quantity called the degree of coupling between the oscillator and the transmission line is introduced. In the system in which the oscillators are coupled with frequency‐dependent transmission lines, the effect of the oscillator coupling system on the synchronization characteristics is investigated. The circuit condition for power combining is found. Good agreement with the experimental results is confirmed.
A measurement and a classification of arcing phenomena of AgPd alloy contacts in low pressure
Authors: Sone Hideaki , Takagi Tasuku 
Published: July 2007

AbstractTo understand the arcing phenomena observed when contact is breaking, an apparatus was developed to observe and record arc voltage waveforms. The apparatus is formed by adding a waveform acquisition circuit composed of an A/D converter, memories and control circuits to the conventional contact measurement system. Using this equipment, the voltage waveforms were observed for Ag, Pd or their alloys contacts for 500 operations under various surrounding ambient pressures. The waveforms were analyzed with respect to length, slope and fluctuation. The waveform tendencies were classified by the combination of ambient pressure and alloy ratio. For example, when the Ag content is high or the ambient pressure is high, the transition to gaseous phase becomes smoother with the increase of operation repetitions. When the Pd content increases and the ambient pressure is low, only a short metallic phase arc occurs. Using the measurement and classification, data for establishing the relationship between the ambient pressure and the contact material was acquired. The classification carried out by using contact resistance was similar to that by arc waveforms.
Direct core observation method using thermal radiation of silica fibers with dopants
Authors: Katagiri Toshiaki , Tachikura Masao , Ishihara Koushi 
Published: July 2007

AbstractVarious direct core observation methods have been developed for directly observing the core itself of a single‐mode optical fiber such that the axial alignment is performed and the splicing loss can be evaluated. In the conventional methods, special devices are needed such as an He‐Cd laser and a collimated illuminating optical source. In this paper, the optical fiber core can be observed directly by thermal radiation when Ge‐doped optical fibers are spliced by glow discharge heating. Also, this phenomenon can be used for splicing. When a Ge‐doped fiber is placed near the glow discharge heating region, the core shines in contrast to the clad. This is because the absorbing loss of the core is larger than that of the clad and hence a stronger thermal radiation occurs from the core. Further, near the wavelength of 420 nm, Ge luminescence exists due to the ultraviolet (UV) light from the glow discharge. The rate of the luminescence of the total radiation from the core is at most one‐twentieth the thermal radiation in a steady‐state splicing situation. Further, the apparent core location is expanded by the amount of refractive index due to the lens effect of the clad. Hence, the true location of the core must be calibrated.
Multilevel storage memory using serial—parallel–serial charge—coupled device
Authors: Nakamura Taichi 
Published: July 2007

AbstractSince the CCD can handle analog signals directly, it is used widely for delay lines, filters, imaging elements and imaging memories. This paper considers the multilevel storage memory of an SPS (serial‐parallel‐serial)‐CCD applied to field memories of image signals. First, a charge transfer model for an SPS‐CCD is created. By means of the transfer function derived from this model, it is clarified that the transfer losses of the serial register and the parallel register degrade the frequency characteristics of the amplitude and phase. It is pointed out that this degradation can be improved significantly by compensation of the transfer losses of the two serial registers and the parallel register. Since realization of a circuit for rigorous compensation of the transfer loss is extremely difficult, a simple transfer loss compensation method is also studied in which the SPS‐CCD is considered as a cascade connection of two serial registers. It is found that the difference in the effect of simple and rigorous compensations is at most 0.6 percent in the case of 50 percent eye degradation. Hence, the effectiveness of the simple compensation is confirmed. Also, by using a commercially available CCD, an experiment for eight‐level storage memory is carried out in which a simple transfer loss compensation is applied. It is confirmed that agreement of the calculated and measured signal error rates is excellent.
CMOS comparator suitable for mixed analog—digital LSIs
Authors: Tsukahara Tsuneo , Ishikawa Masayuki 
Published: July 2007

AbstractA method of analyzing the effects of clock feedthrough and power supply noise on CMOS comparators is described. In addition, a new flip‐flop type comparator with large tolerance to clock feedthrough and power supply noise is developed.First, a method of analyzing clock feed‐through and power supply noise tolerance using small signal analysis of the inverter chopper comparator is described. Next, a new flip‐flop comparator whose tolerance to clock feedthrough and power supply noise is significantly greater than that of the inverter chopper comparators is proposed. Experimental results are also described. The new comparators fabricated using 1.5 μm CMOS technology show a small offset voltage (⩽ 1.5 mV) which is caused mainly by clock feedthrough imbalance. The power supply noise tolerance of these new comparators is almost twenty times larger than that of the inverter chopper comparators.
Design considerations for mode—conversion type optical branching waveguides
Authors: Sawa Shinnosuke , Ono Kazuo , Mori Seiji 
Published: July 2007

AbstractA few comprising methods of mode‐conversion type low‐loss optical branching waveguides are proposed anew, and the fundamental properties are clarified by numerical analysis based on the coupled mode theory. For the analytical model, we select a singlemode slab waveguide, and assume that the waveguide possesses mode transducers at the input and output sides, respectively. The mode transducers are designed in the best possible way for mode conversion from the input to the main part of the branch waveguide and also from that main part to the output waveguide, that is, so as to minimize the radiation loss at the output end of the branching waveguide. The waveguide thus designed has a taper at the input side, and the cross‐sectional shape varies in the direction of the transmission axis. For the analysis, first we calculate the coupling coefficients between the coupled modes of the tapered and branch sections of the three‐layered slab waveguide, respectively. Then we substitute the coefficients into the corresponding coupled mode equation whose solutions are obtained numerically by the Runge‐Kutta‐Gill method. The result of numerical simulations shows that the comprising methods proposed in this paper can reduce the mode conversion loss more remarkably than the other methods known till now.
Geometrical optics field of guided waves. A geometrical interpretation for the field amplitude
Authors: Hashimoto Masahiro 
Published: July 2007

AbstractFollowing a previous report [1], this paper describes the geometrical optics theory applied to waveguides. The ray theory to be used as a foundation is based on the Maupertuis principle. It has been pointed out that the theory is not the one based on Hamilton's principle. Both theories are different in concept. However, the difference in the ray trajectory appears only in anisotropic media. In this paper, the anisotropic medium is assumed to be uniform along the waveguide axis whereas it is inhomogeneous in the cross section. Hence, the conventional isotropic waveguides are included in the present theory. The objective of the paper is to construct geometrically the field of the eigenmode propagating in such a waveguide. Since the construction method for the phase of the field has already been reported, the field amplitude is derived mainly from geometrical considerations. Since some examples coincide with the known results obtained from the field theory, it is presumed that the geometrical interpretation of amplitude holds, in general. New geometrical formulas that cannot be derived from the solutions of the wave equation are obtained.
Analysis of two‐core single‐mode optical fibers for subscriber lines
Authors: Yoshikawa Hiroshi , Ohno Yutaka , Kimoto Hisakazu 
Published: July 2007

AbstractMulticore optical fiber, consisting of several cores in the same clad, has been developed for use as optical fiber cable for subscriber lines, by which high‐density cable can be realized. One of the problems of multicore fiber is crosstalk between adjacent cores. In this paper, a two‐core single‐mode optical fiber, which is the basic structure of the multifiber, is analyzed and an optimum refractive index profile for desired crosstalk and possible high density is discussed. In the analysis, comparison was made between step‐type, W‐type, α‐power and inverse α‐power index profiles, considering the mode field diameter which is an important parameter for a single‐mode optical fiber. The results show that: (1) under the same mode field diameter, the crosstalk for α‐power or for inverse α‐power refractive index profile has little difference with that for the step‐type profile; (2) by the use of the W‐type refractive index profile, high density becomes possible. Based on these results, the design and evaluation of the multifiber can be carried out. To analyze the coupled fiber with a radially inhomogeneous refractive index profile, the point matching method and homogeneous multilayer division method are combined. Although scalar approximation is made in the method, in the case of a weak waveguide, the relative error of coupling coefficients was found to be less than 0.1% even for strong coupling.
Steady‐state analysis of electromagnetic field by vertical electrical dipole over lossy ground
Authors: Ichikawa Satoshi , Karasudani Takashi 
Published: July 2007

AbstractThe lightning discharge effect is shown by a model in which a lightning current climbs to a lightning cloud from the ground. The electromagnetic field induced at the observation point is the integration of the contribution due to an infinitesimal vertical dipole placed on the discharge path integrated along the path from the ground surface to the height of the cloud. When the conductivity of the ground is taken into account, the expression of the electromagnetic field due to the infinitesimal electric dipole contains a term given by a complicated infinite integral called the Sommerfeld integral that includes the Bessel function. For a wave source with an isolated waveform lasting for a short period of time such as the lightning discharge current, the frequency components exist over a broad range. Hence, in the analysis of the transient electromagnetic field by the lightning discharge, the frequency changes significantly with the source location. As a result, the behavior of the integrand in the Sommerfeld integral changes significantly. This paper treats a case in which the wave source varies sinusoidally so that the transient analysis is anticipated and a useful result is obtained for the steady state. To this end, the analysis of the electromagnetic field induced by a vertical electric dipole on the lossy ground is described with special attention given to the numerical processing of the Sommerfeld integral.
Miniaturized optical fiber couplers based on direct–jointing architecture: Loss improvement by a new space–sharing technique
Authors: Sasaki Issei , Yoneta Masaji 
Published: July 2007

AbstractA miniaturized optical fiber directional coupler based on a new space‐sharing technique has been investigated. To obtain a miniaturized size, we propose a direct‐jointing technique, in which the optical fibers to be coupled are directly jointed without an intermediate of any other optical component. Moreover, an intrinsic excess loss of ‐0.0015 dB in the direct‐jointing architecture is theoretically possible for graded‐index multimode optical fiber systems.Instead of the conventional power‐sharing technique with a half‐mirror, we use a space‐sharing technique, in which the optical power is divided in space with a distributed digital reflectance (R = 1 or 0) mirror. The present method is advantageous in that it improves the loss characteristics, particularly at a 1:1 division ratio. The excess loss of the conventional half mirror coupler may be more than 2 dB, but the new technique produced a loss lower than 0.5 dB (at λ = 1.55 μm) in a test sample.
Financial analysis: The methods and their application to employee training
Authors: Mosier Nancy R. 
Published: July 2007

AbstractTraining and development is big business; therefore it should be evaluated in the same way as other large investments, in terms of costs and benefits. In this context, training becomes another tool for a firm's survival. According to Nancy Mosier, although training directors recognize the importance of cost considerations, many still use intuitive methods rather than collecting and analyzing hard numbers to justify their programs. Managers can now take heart because Mosier describes some basic and useful techniques to get the cost‐returns analysis rolling. The same applications as are used to justify capital, land, or other resources can be used to justify training and development. Mosier reviews common capital budgeting techniques; for example, payback time, average rate of return, present value or present worth, internal rate of return, and cost‐benefit ratio, and contrasts these techniques with those now being used in training and development. Much of what is available in training focuses on costs and advocates making decisions only on the basis of costs. Her message is clear—financial analysis in training and development must be made on the basis of both costs and returns for the like of the project, and this article helps training directors to look at the complete picture.
The relationship between trainee responses on participant reaction forms and posttest scores
Authors: Dixon Nancy M. 
Published: July 2007

AbstractIn many organizations, the responses to participant reaction forms are the only data managers use when they decide to offer or revise a training course. Is this appropriate? To address this question the author studied the relationship between posttests (tests taken after the course is finished) and the responses on participants' forms for 1,200 trainees in a large manufacturing company. Although the study found no useful correlation between posttest scores and participants' perceptions of (a) the relevance of the course, (b) their own learning, (c) their enjoyment, or (d) the skill of the instructors, it found significant correlations between participants' enjoyment and the ratings of the instructors.
The pretraining environment: A conceptualization of how contextual factors influence participant motivation
Authors: Cohen Debra J. 
Published: July 2007

AbstractHow a training program is introduced may influence a person's motivation to attend and participate actively in the program. A pretraining environment consisting of factors such as the supervisor's style, co‐workers' attitudes toward and experiences with training, the company's publicity about the program, the program's credibility, and corporate attendance policies may have an important effect on an individual's perception of the importance of training and motivation for attending and performing well in the program. An analysis of these contextual factors suggests propositions to predict the influence of the pretraining environment.
A comparison of data collection methods for assessing training needs
Authors: Preskill Hallie 
Published: July 2007

AbstractThis study determined the relative effectiveness of three different data collection methods for conducting needs assessments and concurrently assessed the professional development needs of human resource development employees in a large metropolitan area. A survey using only closed‐ended items, an open‐ended item questionnaire survey, and focus group interviews were used to understand HRD practitioners' training needs, incentives for participating in professional development activities, preferred scheduling options, and reasons that limit professional development. A combined approach using a closed‐ended survey with focus group interviews resulted in a needs assessment method that was both effective and efficient.
Validity in organizational research: A heuristic model
Authors: McKay David A. , Mink Oscar 
Published: July 2007

AbstractThis article outlines the role of the HRD practitioner as organizational research investigator and describes a model for validating measurement instruments, constructs, and strategies in organizational research. The authors review theoretical and conceptual foundations for validating organizational research and present a validation model anchored in communication theory. Common errors and current issues in validation of measurement in HRD research and practice are identified, and uses of the heuristic validation model are illustrated.