bluuebunny/crossref_metadata_2025 huggingface dataset:
Eye movement based on 3D image of short‐term memory
Authors: Morita Satoru , Oosaki Mituharu , Ishihara Yukio
Published: December 2003

Humans perceive a wide range of space by moving their eyes quickly with an essentially narrow view field, but there is no feeling that the viewpoint is moved quickly. This phenomenon is interpreted as follows. Even though the image of the gaze point moves greatly, the image stored in short‐term memory does not change much. Consequently, this paper proposes a model in which the gaze point can be moved over a wide range by moving the gaze point based on a 3D image stored in short‐term memory. A method is also proposed which generates a 3D image that looks like a human view, using both eyes. Based on the features of the 3D image in short‐term memory, movement of the gaze point over a wide range is actually realized. Movement of the gaze point by both eyes based on the 3D image in short‐term memory is simulated in a virtual world constructed by CG. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(1): 76–85, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10213
Unsharp masking based on the multiscale gradient planes
Authors: Okazaki Hidetoshi , Nakashizuka Makoto
Published: December 2003

In this paper, control of emphasis by the multiscale brightness gradient is introduced for unsharp masking. This provides an improved image emphasis method for realizing effective emphasis for any image with superposed Gaussian noise and low‐contrast images. Unsharp masking is a method of obtaining an enhanced image by applying a high‐pass filter to blurred images so that the obtained high‐pass components are superposed on the original image. However, unsharp masking has the deficiency that the noise is also enhanced due to its principle of operation when noise is superposed on the blurred image. In order to alleviate this problem, this paper proposes a characteristic quantity of image edges (edge information) using the amplitude shift between the scales of the multiscale brightness gradient, and applies it to the control of the emphasis of unsharp masking. The proposed edge information takes a positive value on the image edge and the amplitude is proportional to the smoothness and brightness difference of the edges. Since the proposed edge information takes a positive value at the smoothed edges regardless of the variance of the superposed Gaussian noise and the image contrast, it is possible to reduce the effect of noise in the emphasis result by controlling the image emphasis by discriminating positive or negative values. In the experiment, the proposed edge information is introduced into unsharp masking using a fuzzy rule and into third‐order unsharp masking. The effectiveness of the proposed edge information is confirmed by image emphasis. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(4): 40–54, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10113
Method of evaluation of fractal dimensions in terms of fractional integro‐differential equations
Authors: Koga Hiroyuki , Nakagawa Masahiro
Published: December 2003

In order to evaluate fractal dimensions based on the self‐affine characteristics of time series signals, a method of estimation of fractal dimensions by using fractional integro‐differential equations is proposed. The time series of fractional Brownian functions can be converted to uncorrelated random noise by fractional integro‐differentiation of an appropriate order. By comparing the correlation characteristics of the converted data and the reference data by the maximum likelihood estimation method, the fractal dimension can be evaluated from the minimum of the likelihood function. The estimation accuracy of the proposed method is improved by a factor of about 1.5 in comparison with the maximum likelihood estimation method in which the dimension of the reference data is varied. The standard deviation of the estimation results per reference datum is reduced by a factor of about 0.8. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(4): 30–39, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10136
Unequal error control codes with two‐level burst and bit error correcting capabilities
Authors: Namba Kazuteru
Published: December 2003

In some computer and communication systems, such as in holographic memories, burst errors often occur, and some parts of the word have lower reliability, that is, higher error rate, than the other parts. This paper considers words to be divided into two blocks according to the error rate: a block with higher error rate X1, and the other block with lower error rate X2. This presents a code which corrects l‐bit (≥2) burst errors occurring in X1 as well as single‐bit errors occurring in X2. This also demonstrates an evaluation of the codes on code length and the parallel decoder hardware amount. The check bit length of the proposed code is as short as the bound when the length of block X1 is less than 2l. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(4): 21–29, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10147
Generalized linear‐phase paraunitary nonuniform filter banks
Authors: Kobayashi Yuhiro , Kawada Masahiro , Ikehara Masaaki
Published: December 2003

Uniform filter banks such as the DCT used in JPEG and MPEG have been studied widely. On the other hand, the frequency characteristics of the signal have irregularity. The wavelet transform makes use of such characteristics in nonuniform processing. However, the conventional nonuniform filter banks are constructed with a tree structure of identical two‐channel filter banks. Since the frequency characteristic of each subband filter cannot be designed directly, such a filter bank may not be optimum with regard to the coding efficiency. In the present paper, a method of configuration of generalized linear‐phase paraunitary nonuniform filter banks is presented. A realization using a lattice structure that preserves orthogonality and the linear‐phase property is proposed. Finally, the obtained nonuniform filter bank is applied to image coding and the effectiveness of the proposed method is confirmed. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(4): 12–20, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10150
Closed‐form expression of RLCG transmission line and its application
Authors: Tanji Yuichi , Ushida Akio
Published: December 2003

In this paper, a closed‐form expression and a macro model for simulation are proposed for the RLCG transmission line expressed in terms of the telegrapher's equation. First, the hyperbolic functions contained in the admittance matrix of the transmission line are analytically expanded in terms of poles and residues, deriving a close expression of the admittance matrix. Next, from the closed‐form expression, rigorous poles of the admittance matrix are obtained. By using the closed‐form expression, a macro model of the RLCG transmission line is obtained. The passivity of the macro model, a method for determination of the order, and a simulation method in the time domain are discussed. As a numerical example, a closed‐form expression and a traditional discretized model of a transmission line are compared. In this way, the effectiveness of the macro model obtained from the closed‐form expression is confirmed. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(4): 1–11, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10155
Development of Robovie as a platform for everyday‐robot research
Authors: Kanda Takayuki , Ishiguro Hiroshi , Ono Tetsuo , Imai Michita , Maeda Takeshi , Nakatsu Ryohei
Published: December 2003

In the design of everyday robots which communicate with humans in ordinary life, particular attention must be devoted to interactions and relationships in order to achieve natural and smooth communications. For this purpose, Robovie, which we developed, is equipped with hardware mechanisms suitable for communication, such as a rich inventory of sensors, an appearance that is readily personified, and a gesture expression ability comparable to that of humans. In addition, its programs have a software architecture that was designed for easy realization of interactive functions. As a result of these distinctive features, Robovie is suitable for use as a platform for research on humanized robots, such as research on communications between robots and humans, and on the body form of robots. This paper describes its hardware and software architecture. The usefulness of Robovie as a research platform is demonstrated by experiments designed to verify its interactive functions. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(4): 55–65, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10169
Texture segmentation using amplitude and phase information of Gabor filters
Authors: Tanaka Hideo , Yoshida Yasuo , Fukami Kimihiko , Nakano Hiroki
Published: December 2003

This paper proposes a method in which the amplitude and phase information of a two‐dimensional Gabor filter output are utilized in the supervised segmentation of texture images. The segmentation procedure is as follows. The amplitude and the phase difference between adjacent pixels of the multiple filter outputs are used as the feature parameters. By applying maximum‐likelihood estimation of each pixel in the test image, it is decided to which supervised image the pixel belongs. Then, based on the result of segmentation, maximum a posteriori probability estimation is iteratively applied and the final result of segmentation with region integration is obtained. It is shown that when the number of filters in the frequency space is smaller, the phase difference feature parameter contains information which cannot be obtained by using only the amplitude feature parameter. In particular, it is experimentally shown to be effective to weight the phase difference feature parameters by the amplitude. The accuracy of segmentation can be improved by thus combining the phase difference with the amplitude feature parameter. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(4): 66–79, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10170
High‐repetition‐frequency short pulses in a VHF discharge‐excited slab‐type carbon dioxide laser using an ultrasonic vibrator
Authors: Mori Akira , Suzuki Kaoru
Published: December 2003

We propose a novel method for producing high‐repetition‐frequency short pulses with a halved confocal configuration consisting of an unstable concave–convex resonator in a very high frequency (VHF) discharge‐excited slab‐type carbon dioxide laser. This method utilizes a fully reflective concave mirror with variable curvature which can be controlled by a piezoelectric device.

In general, slab lasers are modulated directly by varying the pulse voltage. However, because plasma fluctuation occurs at the pulse transitions, the repetition frequency is less than 10 kHz and the minimum pulse width is 1 µs. On the other hand, in our method there is no disturbance of the plasma, because the power source is not modulated. There is also little mechanical constraint, because we use a piezoelectric device. As a result, pulse shortening with a high repetition rate is possible. The pulse shape is well reproduced by a three‐level rate equation.

The mechanism of the method involves changes in ejection efficiency with periodic variation of the radius of curvature of the mirror. Good agreement between observations and calculations was also obtained for the peak power and the pulse width.

In this paper we compare measurements with calculations. The possibility of achieving high repetition rate oscillation and pulse shortening by this method is examined. The results confirm the possibility of achieving a repetition frequency between 1.4 kHz and 170 kHz. The shortest pulse width that can be achieved is 160 nanoseconds. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(3): 1–7, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10127
Precise position control of an ultrasonic motor using the PID controller combined with NN
Authors: Tanaka Kanya , Oka Masato , Uchibori Akihiko , Iwata Youichirou , Morioka Hiroshi
Published: December 2003

The input‐output characteristic of an ultrasonic motor (USM) has nonlinear elements and changes with a temperature rise or fluctuation of load‐mass. Therefore, it is difficult to accomplish satisfactory control performance by using conventional PID controllers. In this paper, we propose a PID controller combined with a neural network (NN‐PID controller). In this design method, the controller gains consist of constant gains of the PID controller and variable gains of the NN controller. The weights of the NN are adjusted by the backpropagation method so that the control error can be minimized. This method does not require long learning time of the NN. The effectiveness of the proposed design method is confirmed by experiments using an existing USM. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(3): 46–54, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10199
A power compensation and control system for a partially shaded PV array
Authors: Mishima Tomokazu , Ohnishi Tokuo
Published: December 2003

The power–voltage and current–voltage characteristics of a PV array change with the variation of insolation and temperature. In particular, the output power of a PV‐panel block consisting of series‐PV modules inevitably goes down due to partial shading caused by peripheral obstacles. This results in a significant reduction of the total output power from the PV power generation system where a couple of PV blocks are parallel to the DC terminal of interactive inverter because of mismatch of the optimum operating voltages between the PV blocks.

In this paper, we propose a power conversion system to compensate the output power of a partially shaded PV array. The proposed system can control the output power of the PV array on a PV block basis, which contributes to a more efficient and simpler implementation of the PV power compensation system than that by individual controls of PV modules using DC–DC converters. In addition, inverter DC voltage is appropriately controlled so that the maximum output power from the overall PV array can be obtained. Then, the feasibility of the system is investigated and verified from the simulation and experimental results. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(3): 74–82, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10203
Dielectric characteristics of oil‐filled transformer in the presence of nonstandard lightning surge waveforms
Authors: Okabe Shigemitsu , Kawashima Takeshi , Inoue Tamotsu , Teranishi Tsuneharu , Nagaoka Satoshi
Published: December 2003

To achieve a rational insulation design for transformers, it is important to evaluate dielectric strength against surges actually impinging on equipment on‐site. This paper deals with the breakdown voltage characteristics of an oil gap under nonstandard lightning surge waveforms combined with oscillatory voltages. It is found that the breakdown voltages of the oil gap under nonstandard impulse waveforms are higher than standard lightning impulse voltages. The results can be ascribed to V–t characteristics of the oil gap in short‐time impulse voltage ranges. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(3): 39–45, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10229
Gain‐scheduled velocity and force controllers for electrohydraulic servo system
Authors: Sugiyama Takahiro , Uchida Kenko
Published: December 2003

The load variation of the electrohydraulic servo system causes degradation of the control characteristic. This is because the flow characteristic of the flow control valve depends on the load condition. Here, we propose the flow calculation formula to have continuous flow between turbulent and laminar flow so that we compose the linear plant model with a scheduling parameter. Then, we design gain‐scheduled controllers for the velocity and hydraulic force control. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(3): 65–73, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10239
Interior structure of UPQC‐type QCC at the low‐voltage side in the FRIENDS
Authors: Noda Toshiyuki , Wang Guobin , Kita Hiroyuki , Tanaka Eiichi , Hasegawa Jun
Published: December 2003

Recently, the worldwide deregulation of the electric power industry is progressing. Further, it is expected that a many distributed generation facilities and energy storage systems will be installed at the end point of the power systems. Therefore, the future power system must be able to cope with these various qualities of power in the deregulated situation. The authors have proposed the FRIENDS (Flexible, Reliable, and Intelligent ENergy Delivery System) concept as a new distribution system that copes with a new framework of the electric power business in the near future. The most typical aspect of FRIENDS is the introduction of new equipment; Quality Control Centers (QCC) between distribution substations and customers. In this paper, the authors propose a concrete interior structure and investigate some control methods for realizing unbundling power quality supply and power conditioning using the proposed UPQC‐type QCC. The effectiveness of the proposed method is confirmed through the instantaneous value analysis using PSCAD/EMTDC. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(3): 26–38, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10243
Sensorless controls of salient‐pole permanent magnet synchronous motors using extended electromotive force models
Authors: Ichikawa Shinji , Chen Zhiqian , Tomita Mutuwo , Doki Shinji , Okuma Shigeru
Published: December 2003

In this paper, we propose a new mathematical model for synchronous motors and a sensorless control method based on it. To control permanent magnet synchronous motors, knowledge of rotor position and velocity are necessary. Heretofore, expensive sensors have been used to detect rotor position information. Although many sensorless control methods based on the electromotive force (EMF) have been developed for non‐salient‐pole permanent magnet motors, they cannot be applied for salient‐pole motors without approximation because of complications in the mathematical model; this is turn may lead to problems of instability. To solve this problem, we propose an extended electromotive force model for synchronous motors. The proposed model has a simple structure, making position estimation possible without approximation. Experimental results show that the proposed model and method are valid. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(3): 55–64, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10257
Generation planning including distributed generators under uncertainty of demand growth
Authors: Muroaka Yukari , Oyama Tsutomu
Published: December 2003

This paper addresses the problem of generation planning in the competitive power market with uncertainty of demand growth. The distributed generator (DG) is given attention against a large‐scale generator to correspond to uncertain demand growth. Optimization consists of minimizing the average cost and hedging risk over the scenario trees of demand growth. At first, based on the idea of a Real Option, Dynamic Programming using the utility function is applied to generation planning. Utility functions can model investor's risk‐return profile. The decisions in the first stage indicate that they are influenced by the type of utility functions and demand growth scenarios, and data of generators. Next, a Monte Carlo simulation is applied to a Brownian motion model of demand growth. This model can increase the possible number of demand levels. With this simulation, the case that the distributed generator has an advantage over the large‐scale generator is quantitatively discussed. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(3): 17–25, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10276
High frequency model of transformer winding
Authors: Shibuya Yoshikazu , Fujita Shigeto
Published: December 2003

A high frequency model of transformer winding is used to analyze the voltage oscillations due to various excitations such as the very fast transient overvoltage which occurs at the time of disconnecting switch operations. Usually, a circuit of interlinked inductances and capacitances is used for this purpose, in which circuit parameters have to be properly determined. Previously, those constants have been estimated taking the coil section pair as a unit. In the method proposed here, the section pair can be further subdivided. The time‐domain calculation is conducted combining the frequency analysis and FFT technique. The voltage oscillations of the winding subjected to the lightning impulse are calculated. The correspondence with the experimental results is satisfactory. The response to a chopped impulse shows this method's applicability to high frequency analysis. Since the constants are calculated directly from the design parameters of transformer winding, this technique is particularly useful in developing and designing transformers. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(3): 8–16, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10280
Chinese perceptions of implied hazard for signal words and surround shapes
Authors: Yu Rui‐feng , Chan Alan H.S. , Salvendy Gavriel
Published: December 2003

With the increase of international trade and communications, the issue—whether people in different cultures similarly interpret and understand the extent implied by signal words and their associated panels in warning design—is getting more and more interesting and important. Two experiments were conducted to collect data on perception of arousal strength of signal words and surround shapes of the Chinese population and to determine whether those findings for Chinese are validated for Americans. A total of 120 Chinese mainland subjects were tested in each of the experiments. In Experiment 1, 16 Chinese signal words were tested for their arousal strength. The results indicated that the words could imply different levels of hazard for the Chinese population. The comparative results revealed that both the Chinese and the Americans perceived similar levels of hazard in a signal word. In Experiment 2, six signal words and five different shapes were factorally combined to receive ratings on the perceived hazard level. Data indicated that both surround shapes and their interaction with signal words could connote different levels of hazard by the Chinese population. Their rank ordering of the shapes was found to be almost consistent with that of the Americans. Strong gender, age, and career effects were found in the two experiments. In general, there is only a minor difference in the perceived hazard for signal words and surround shapes between Chinese and American participants. However, it is suggested that care should be taken when the warning signs in facilities are designed for different populations. © 2004 Wiley Periodicals, Inc. Hum Factors Man 14: 69–80, 2004.
Potential uses of technology to communicate risk in manufacturing
Authors: Smith‐Jackson Tonya L. , Wogalter Michael S.
Published: December 2003

Technological advances already implemented in other systems can be used to design and deliver warnings and other risk communications in a variety of occupational settings, including manufacturing environments. This article discusses technologies that could be used to design and deliver risk communications. Examples are discussed in terms of potential applications and protocols. As with many advancements, there are new challenges, including ethical considerations both inside and outside the workplace environment. These issues are discussed along with initial approaches to resolve expected ethical conflicts and implement advanced risk communication systems (ARCS). © 2004 Wiley Periodicals, Inc. Hum Factors Man 14: 1–14, 2004.
Situation awareness and attention allocation measures for quantifying telepresence experiences in teleoperation
Authors: Riley Jennifer M. , Kaber David B. , Draper John V.
Published: December 2003

This study assessed the utility of measures of situation awareness (SA) and attention allocation for quantifying telepresence, the sense of being present at a remote site, in a teleoperation task scenario. Attention and SA have been identified as cognitive constructs potentially underlying telepresence. The motivation for this research was to establish an objective measure of telepresence and investigate the relationship between telepresence and teleoperation performance. Twenty‐four research participants performed a virtual ordnance disposal task at varying levels of difficulty (LODs). The task involved locating, identifying, and disposing of virtual land mines in an outdoor environment using a simulated remote‐control rover with a robotic arm. Performance, SA, and attention allocation were recorded along with subjective assessments of telepresence. Results demonstrated LOD effects on performance and telepresence. Regression analysis revealed LOD and attention to explain significant portions of the variance in telepresence. Results of the study provide further evidence that telepresence may share a relationship with performance, and that cognitive constructs, such as attention and SA, may serve as alternative, objective measures of telepresence. © 2004 Wiley Periodicals, Inc. Hum Factors Man 14: 51–67, 2004.
Identifying mobile phone design features critical to user satisfaction
Authors: Han Sung H. , Kim Kwang J. , Yun Myung H. , Hong Sang W. , Kim Jongseo
Published: December 2003

A variety of mobile phones are available to consumers. They differ from each other in many design features including shape, color, size, and material. This study attempts to identify some of the design features of a mobile phone critical to user satisfaction. Empirical models linking design features to satisfaction levels were developed and used to identify critical design features. Design properties common to “desirable” and “undesirable” phones were then extracted by comparing the values of the critical design features. The approach used in this study may help the product designers identify critical design features with their desirable properties in a systematic manner. © 2004 Wiley Periodicals, Inc. Hum Factors Man 14: 15–29, 2004.
Using feedforward neural networks and forward selection of input variables for an ergonomics data classification problem
Authors: Chen Chuen‐Lung , Kaber David B. , Dempsey Patrick G.
Published: December 2003

A method was developed to accurately predict the risk of injuries in industrial jobs based on datasets not meeting the assumptions of parametric statistical tools, or being incomplete. Previous research used a backward‐elimination process for feedforward neural network (FNN) input variable selection. Simulated annealing (SA) was used as a local search method in conjunction with a conjugate‐gradient algorithm to develop an FNN. This article presents an incremental step in the use of FNNs for ergonomics analyses, specifically the use of forward selection of input variables. Advantages to this approach include enhancing the effectiveness of the use of neural networks when observations are missing from ergonomics datasets, and preventing overspecification or overfitting of an FNN to training data. Classification performance across two methods involving the use of SA combined with either forward selection or backward elimination of input variables was comparable for complete datasets, and the forward‐selection approach produced results superior to previously used methods of FNN development, including the error back‐propagation algorithm, when dealing with incomplete data. © 2004 Wiley Periodicals, Inc. Hum Factors Man 14: 31–49, 2004.
Improving performance and quality of working life: A model for organizational health assessment in emerging enterprises
Authors: Shoaf Christin , Genaidy Ash , Karwowski Waldemar , Huang Samuel H.
Published: December 2003

The organization of work has been addressed through numerous perspectives by a diverse set of disciplines. While job stress research has focused on the promotion of worker well‐being, contemporary business‐improvement initiatives (e.g., lean manufacturing, six sigma) have sought to optimize effectiveness through work processes. However, these two aims, although traditionally viewed as contradictory, are actually interdependent variables in the determination of long‐term profitability. The concept of organizational health blends the pursuit of individual wellness with organizational effectiveness to yield a strategy for economic resilience. This article introduces a novel model for organizational health assessment using a systemic approach that addresses work factors at the individual, job, process, and organizational levels. © 2004 Wiley Periodicals, Inc. Hum Factors Man 14: 81–95, 2004.
Relationship between platinum wire temperature and catalytic heat release rate on platinum in unsteady‐state hydrogen–air mixture
Authors: Nakamura Daisuke , Nagata Harunori , Totani Tsuyoshi , Kudo Isao
Published: December 2003

The authors have proposed a hydrogen concentration probe using a catalytic reaction on the surface of a platinum wire. To use this probe for detecting the concentration change in a supersonic mixing layer, the response of the catalytic heat release rate must depend only on the change of concentration around the probe. The catalytic heat release rate on the surface of the platinum wire in an unsteady state was measured by a constant‐temperature hot‐wire anemometer and a shock tube to investigate the relationship between the response of the catalytic heat release rate and the temperature of the platinum wire. The catalytic heat release rate began increasing upon the introduction of the shock wave. The rate of increase of catalytic heat release depended on the temperature of the platinum wire when the temperature of the hot wire was low. However, the dependence was very weak when the temperature of the hot wire was above 400°C. This shows that it is not the catalytic reaction but rather molecular transfer from the flow to the surface of the platinum wire is the controlling step when the temperature of the platinum wire is high. In conclusion, the temperature of the platinum wire must be above 400°C to use the hydrogen concentration probe in a supersonic mixing layer. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(1): 1–11, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10129
A simple method for predicting the performance of a heat exchanger mounted in an air conditioner (1st report, proposed reduced‐mesh analysis modeling method)
Authors: Kudoh Mitsuo , Sasaki Shigeyuki , Hatada Toshio , Morimoto Motoo
Published: December 2003

To analyze the performance of a heat exchanger (HEX) used in air conditioners within a realistic time frame, a simple method—based on a reduced‐mesh calculation model—was developed. The pressure loss caused by the HEX is given by a momentum source term, and the heat‐transfer performance of the HEX is approximated by using a wall function as the boundary condition. The analytical results from this simple analysis model (under a fin‐pitch range of 1.0 to 1.6 mm) were compared with experimental measurements of pressure loss and heat‐transfer performance. This comparison showed that the pressure loss from the simple analysis model agrees with the experimentally measured loss (within 3% error) and that the heating capacity determined by the simple model agrees with the experimentally measured one (within a 1% error). © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(1): 12–23, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10130
Experimental study on flow characteristics of a sleeved jet into a main crossflow
Authors: Wu H.L. , Chen T.K. , Luo Y.S. , Gong W.Q.
Published: December 2003

Experiments were carried out on the hydraulic mechanism of the thermal shock caused by cold jet injection at a T‐junction with thermal sleeve in the reactor cooling system using digital particle imaging velocimetry (DPIV) technique to measure the flow in the main duct and in the annular space of the sleeve tube. The flow and vorticity characteristics were investigated at jet‐to‐crossflow velocity ratios of 0.5 to 4. There was a stream of discharge from the annular space at the rear part of the sleeve near the jet exit, which resulted in decreasing the influence of the jet on the downstream wall. The intensive vorticity in the near wake mainly originated from the shear layer vorticity of the jet and the annular discharge stream. The intensive vorticity soon broke down and dissipated, and further developed into the counterrotating vortex pair in the far wake. The flow in the annulus was closely dependent on R, and thermal protection of the sleeve would become evident at higher R. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(1): 24–31, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10131
Numerical simulation of high‐temperature phase change heat storage system
Authors: Xing Yu‐Ming , Xu Xin , Yuan Xiu‐gan , Cui Hai‐Ting , Zhang Yun‐hao
Published: December 2003

In this paper, numerical results pertaining to cyclic melting and freezing of an encapsulated phase‐change material (PCM) have been reported. The cyclic nature of the present problem is relevant to latent heat thermal energy storage system used to power solar Brayton engines in space. In particular, a physical and numerical model of the single‐tube phase change heat storage system was developed. A high‐temperature eutectic mixture of LiF‐CaF2 was used as the PCM and dry air was used as the working fluid. Numerical results were compared with available experimental data. The trends were in close agreement. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(1): 32–41, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10132
Design of miniature loop heat pipe
Authors: Chu C.I. , Wu S.C. , Chen P.L. , Chen Y.M.
Published: December 2003

In the present study, the loop heat pipe (LHP) was miniaturized for application to electronic cooling. According to the capillary limitation, the wick structure parameters that would affect the heat transfer capacity were analyzed theoretically. Among the various wick parameters, this study especially investigated the effect of wick thickness, which has rarely been mentioned in the literature. Here, various thicknesses were analyzed theoretically and then tested experimentally. The results showed that the temperature on the evaporator wall dropped with decreasing wick thickness. This effect would lead to the raising of heat transfer capacity and the descending of thermal resistance. According to the analysis and the practical demand for electronic cooling, a miniature LHP was fabricated with the evaporator outer diameter of 13 mm and the evaporator length of 50 mm. The testing results showed that, at the allowable working temperature of 80 °C, the maximum heat transfer capacity was up to 200 W and the thermal resistance was 0.17 °C/W. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(1): 42–52, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10133
Numerical simulation of coupled radiation‐convection heat transfer of high‐temperature developing flow in tube
Authors: Xia Xin‐Lin , Zhang Hao‐Chun , Tan He‐Ping , Ma Guo‐Song
Published: December 2003

By combining the discrete ordinate method with the control volume method, the coupled radiation‐convection heat transfer of high‐temperature developing laminar flow in a tube is investigated numerically. The radiative transfer is solved by the discrete ordinate method and its contribution to thermal balance is dealt with as a source term in the energy equation, which is solved, as well as the momentum equation, by the control volume method. The effects of medium optical thickness and tube wall temperature on the temperature distribution in medium as well as the heat flux and local Nusselt number on wall are analyzed. The results show that the radiation heat transfer of high‐temperature medium influences the temperature distribution and convection heat transfer greatly, and plays an important role in the heat transfer of developing laminar flow in a tube. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(1): 53–63, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10135
Coupled radiation‐convection heat transfer of high‐temperature participating medium in heated/cooled tubes
Authors: Xia Xin‐Lin , Huang Yong , Tan He‐Ping , Ren De‐Peng
Published: December 2003

The coupled radiation‐convection heat transfer of high‐temperature participating medium in heated/cooled tubes is investigated numerically. The medium flows in a laminar and fully developed state with a Poiseuille velocity distribution, but the thermal status is developing. By the discrete ordinate method, the nonlinear integrodifferential radiative transfer equation in a cylindrical coordinate form is solved to give the radiative source term in the energy equation of coupled heat transfer. The energy equation is solved by the control volume method. The local Nusselt number and wall heat flux of convection as well as the total wall heat flux are employed to evaluate the influence of radiation heat transfer on convection. The analysis shows that the radiation heat transfer weakens the convection effect, promotes the temperature development, and significantly shortens the tube length with obvious heated/cooled effect. There is an obvious difference between the coupled heat transfer in a heated tube and that in a cooled tube, even though the medium properties are kept constant. The wall emissivity, the medium thermal conductivity and scattering albedo have significant influences on the coupled heat transfer, but the effect of medium scattering phase function is small. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(1): 64–72, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10137
Year‐round observations of the energy and water vapour fluxes above a boreal black spruce forest
Authors: Arain M. A. , Black T. A. , Barr A. G. , Griffis T. J. , Morgenstern K. , Nesic Z.
Published: December 2003

Fluxes of energy and water vapour were measured continuously over an ∼120‐year‐old black spruce (Picea mariana (Mill.) B.S.P.) forest in northern Saskatchewan, Canada, from 6 May 1999 to 5 May 2001 using the eddy covariance technique as part of the Boreal Ecosystem Research and Monitoring Sites (BERMS) program. These results demonstrate that long‐term eddy covariance fluxes can reliably be measured during the harsh boreal winter. Typical daytime bulk surface conductance values were about 5–8 mm s−1 during the growing season. Surface conductance sharply declined after midday in response to increasing vapour pressure deficit. The monthly mean values of energy balance components showed that, in spring (March–June), partitioning of available energy flux was mainly in the form of sensible heat, which changed to almost equal proportions of sensible and latent heat in the summer (July–October). In winter (November–February), most of the net radiation was balanced by sensible heat flux. The monthly mean values of net radiation, sensible heat and latent heat flux were about −20 to 20 W m−2, −10 to 25 W m−2 and 5 to 10 W m−2 respectively in winter. The average mid‐day Bowen ratios were approximately 3·5, 1·7 and 5·2 in the spring, summer and winter seasons respectively. The maximum daily evaporation was about 3·5 mm day−1 in summer and 0·1–0·25 mm day−1 in winter. Over the 2 year period, the accumulated precipitation was 835 mm; this compared with 711 ± 70 mm of evapotranspiration, which showed that more than 85% of water was returned to the atmosphere through evapotranspiration. This study reports the first complete annual cycles of energy and water vapour fluxes at this black spruce site. Since black spruce is the dominant tree species in the North American boreal forest, these results have significance for regional and global energy and water cycles. Copyright © 2003 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Spring flood analysis using the flood‐duration–frequency approach: application to the provinces of Quebec and Ontario, Canada
Authors: Javelle Pierre , Ouarda Taha B. M. J. , Bobée Bernard
Published: December 2003

Most often, flood frequency analysis describes a flood event only by its peak. However, the true flood severity is also defined by its volume and duration. This paper presents an approach allowing flood events to be considered in a more complete way: the flood‐duration–frequency (QdF) approach. In a similar manner to the rainfall intensity–duration–frequency analysis, averaged discharges are computed over differentfixeddurationsd. For each duration a frequency distribution of maximum averaged discharges is studied. Finally, a continuous formulation is fitted, as a function of the return periodTand the durationdover which discharges have been averaged. The proposed model has been tested for 169 catchments in the provinces of Quebec and Ontario, Canada. The shapes of the QdF curves enabled us to define different types of flood behaviour and to identify the corresponding geographic regions. This mapping of flood behaviour was the basis for the delineation of seven homogeneous geographical regions, containing catchments having the same hydrological behaviour as is required for regional flood frequency analysis. Copyright © 2003 John Wiley & Sons, Ltd.
Assessment of the impact of meteorological network density on the estimation of basin precipitation and runoff: a case study
Authors: St‐Hilaire André , Ouarda Taha B. M. J. , Lachance Marius , Bobée Bernard , Gaudet Jocelyn , Gignac Claude
Published: December 2003

In recent years in North America, a number of government agencies and industries have begun to reinvest in meteorological networks. This investment must be based on sound scientific advice. Increased meteorological station network density can be beneficial for a number of purposes, including flood forecasting. This study aimed at investigating the impact of network density at two temporal scales, i.e. for the estimation of total annual precipitation and for the estimation of daily precipitation during specific rain events. This was done using kriging as a means to estimate the spatial distribution and variance of rainfall. Kriged precipitation from two network scenarios (sparse and dense) were used as input into the HSAMI hydrological model and simulations were compared on five drainage basins in the Mauricie area (Québec, Canada).

A comparison of the distribution of total annual precipitation interpolated from the two network scenarios showed that adding stations changed the distribution and magnitude of rainfall in the study area. High precipitation cells were better defined with the denser network, and decreases in the relative spatial variance were observed. Similarly, kriged daily precipitation provided a more defined spatial distribution of rainfall during important rain events of 1999, and variance was also reduced when the denser network was used.

Finally, simulations performed with the HSAMI model were generally improved when the precipitation inputs were estimated using a denser station network for most drainage basins studied, as expressed by increased Nash coefficients and a decreased root‐mean‐square error. Peak flows during important summer flood events were generally better simulated when a denser network was used to calculate the mean daily precipitation used as input. Total cumulated volume estimations during the rain events were also generally improved with a denser network.

This study showed that the estimation of variance remains an important tool for rain gauge network design. Moreover, network density was shown to have an important impact on the quality of flow simulations, even when a lumped model is used. Copyright © 2003 John Wiley & Sons, Ltd.
An analysis of the ground‐penetrating radar direct ground wave method for soil water content measurement
Authors: Galagedara L. W. , Parkin G. W. , Redman J. D.
Published: December 2003

The spatial variability of soil water content can be measured with the ground wave velocity of ground‐penetrating radar (GPR) using short antenna offsets, but picking the correct ground wave arrival time is rather difficult. In applying the GPR ground wave method to soil water content estimation it is also important to know the effective sampling depth of the method. Uniform drainage experiments were conducted with 100 and 450 MHz GPR antennas using 1·0 and 2·0 m fixed antenna separations on a sandy loam soil to investigate time zero picking methodologies and to estimate the sampling depth of the GPR method. The GPR water content data were compared with time‐domain reflectometry (TDR)‐measured data using six vertical TDR probes of different lengths. Time zero was calculated from an air calibration at a 2·0 m antenna separation and from wide‐angle reflection and refraction data, and a difference was found between the two time‐zero calibration methods. A method was analysed to determine the arrival time of the leading edge of the direct ground wavelet using the arrival time of the peak amplitude, since the arrival time of the leading edge of the ground wave can be difficult to pick. Regression analysis showed that the GPR (100 MHz) measured water content was not different from the water content measured with TDR at 0–0·1 m depth, implying that this may be a reasonable estimate of the GPR ground wave method's sampling depth. A similar analysis based on the differences between the 0–0·2 m TDR and the GPR shows that the effective sampling depth of the direct ground wave of the 450 MHz data is less than the sampling depth of the 100 MHz data. Copyright © 2003 John Wiley & Sons, Ltd.