bluuebunny/crossref_metadata_2025 huggingface dataset:
ChemInform Abstract: Synthesis of a Highly Unsaturated Fatty Acid Moiety of Lipo‐ Oligosaccharides Determining Host‐Specificity in Rhizobium.
Authors: VERDUYN R. , LAGAS R. M. , DREEF C. E. , VAN DER MAREL G. A. , VAN BOOM J. H.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Reaction of Coenzyme PQQ with Amino Acids. Oxidative Decarboxylation, Oxidative Dealdolation (Cα‐Cβ Fission) and Oxazolopyrroloquinoline (OPQ) Formation.
Authors: ITOH S. , MURE M. , SUZUKI A. , MURAO H. , OHSHIRO Y.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Structure of Penicillin V Benzyl Ester Sulfoxide
Authors: SHIN W. , KIM JAHEON , KIM JOOHYUN
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Structure of Concanamycin A Pentahydrate.
Authors: NAKAI H. , MATSUTANI S.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: New Stereocontrolled Approach to the Insect Sex Pheromone Serricornin.
Authors: SZURDOKI F. , NOVAK L. , BAITZ‐GACS E. , SZANTAY CS.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Chemical Phase Diagrams for the YBa2Cu3O7 Family
Authors: KAREN P. , BRAATEN O. , KJEKSHUS A.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Design, Synthesis, and Evaluation of Functional Analogues of CC‐1065 and the Duocarmycins: A Study of Structural Features Effecting DNA Binding Selectivity
Authors: BOGER D. L.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Stereochemistry of Methyl and Methoxy Substituents in Polycyclic Hydrocarbons
Authors: BRIANT C. E. , JOHNSON O. , JONES D. W. , SHAW J. D.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Cycloaddition and Cyclization Reactions of Unsaturated Sulfones in Organic Synthesis
Authors: PADWA A. , MURPHREE S. S.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis of Pyrido(3,2,1‐kl)phenothiazine, Quino(8,1‐bc)(1,4) benzothiazepine and Their Derivatives
Authors: CATSOULACOS P. , CATSOULACOS D.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: High‐Tc Superconductors: A Background for μSR Measurement
Authors: GOUGH C. E.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: The Impact of NMR Spectroscopy in Molecular Sieve Characterization. Part 2. Investigations of Highly Siliceous Systems
Authors: FYFE C. A. , GRONDEY H. , FENG Y. , GIES H. , KOKOTAILO G. T.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Direct marketing and online consumer information services (OLCISs): Implications and challenges
Authors: Wayne Talarzyk W. , Widing Robert E.
Published: July 2007

For over 25 years the idea of consumers using computers to shop electronically, and to receive all types of information directly into their homes, has been put forth as the wave of the future. During the early 1980s a number of such services were tested and brought to the marketplace. But consumers showed little interest in the electronic information services and the ability to shop via such services. Today there seems to be a renewed interest in such computer information services and the potential they offer for direct marketing. A few online consumer information services (OLCISs) have shown slow but steady growth during the past few years, and a number of new services have been introduced with some market acceptance more recently. Several such systems are mentioned as part of Business Week's cover story articles on interactive media (20) and retailing's new frontier (27). We believe that a critical mass of OLCISs is beginning to form and that it is time for marketers and academics to give more attention to these emerging technologies. Our comments toward that end are organized in several major areas. At the outset it is important to look at the beginnings of OLCISs to help achieve an appreciation of how these services have developed. Then we want to examine some of the relevant literature on the retailing status and potential of OLCISs. To provide a more current perspective on OLCISs and where they are likely to lead in the coming years, we present survey results concerning the opinions and attitudes of 100 key informants about OLCISs in general, and their use for retailing in particular. We conclude with implications and challenges for direct marketers and academics.
Using motivation as a basis for understanding and improving direct marketing relationships
Authors: Corey Robert J. , Wilson David T.
Published: July 2007

This article describes a practicable framework for research directed toward understanding and improving direct marketing relationships. Rhetorical theory is used to describe the vocabularies of motive underlying the formation of buyer–seller relationships. The perspectives and adaptive strategies revealed in buyers’ language form the basis for understanding the demands and requirements of direct marketing strategies intended to improve buyer–seller relationships. The use of the framework is illustrated by identifying and comparing language in a business-to-business direct marketing context. We conclude the article with a discussion of managerial implications and directions for future research.
Inquiry Management: Contact Decision Rules
Authors: Hansotia Behram J.
Published: July 2007

This article develops the technology for evaluating contact decisions over time. It is assumed that a company has a database of inquirers and wishes to determine who should be selected to receive a potential stream of contacts. Individuals are first evaluated for receiving the initial contact with a break-even rule based on customers’ lifetime values and the potential of receiving up to four contacts. Those contracted who fail to respond are reevaluated for the second contact, and so on. The latter half of the article discusses the longitudinal response model that is needed to predict conditional response probabilities for evaluating the decision rules. This model is based on recent work on discrete survival models using logistic regression.
Consumer awareness of name removal procedures: Implications for direct marketing
Authors: Culnan Mary J.
Published: July 2007

Providing consumers an opportunity to remove their names from mailing lists is one method for addressing rising consumer concerns about privacy. Name removal is also central to the success of the industry's self-regulatory programs. However, 52 percent of the public, including 45 percent of those who shop by mail, are not aware of name removal procedures. This study investigates how consumers who are aware of name removal differ from those who are not, based on an analysis of the raw data from the 1991 Harris-Equifax Consumer Privacy Survey (17). Consumers who are unaware of name removal are more likely to be young and to be African-American, and less likely to be well-educated, to have shopped by mail, and are less likely to be concerned about privacy than consumers who are aware.
Mail order catalog design and consumer response behavior: Experimentation and analysis
Authors: Seaver Bill L. , Simpson Eithel
Published: July 2007

A mail order firm wanted a strategy to increase response rates through catalog design. The strategy involved an indistinguishable experimental section within the main catalog to avoid prohibitive costs of putting together 16 totally unique catalogs and utilized Plackett–Burman screening designs, multivariate methods, and robust methods. The end result was an economically feasible new strategy that provided an increased profit-cost ratio, better catalog design, prediction of customer response data, important product perspectives, and marketing strategies for long-term impact.
Direct marketing and the use of individual-level consumer information: Determining how and when “privacy” matters
Authors: Nowak Glen J. , Phelps Joseph
Published: July 2007

The desire to maximize marketing effectiveness and reduce communication costs has increased direct marketers’ reliance on computerized databases, customized persuasion, and other consumer information intensive strategies and tactics (28,54). The belief that the success of marketing efforts is positively related to the amount and specificity of individual-level consumer information (7), however, has raised questions about how far companies should be allowed to go in learning about or attempting to persuade consumers (6,40). In the process, privacy has become widely evoked, but often elusive concept. This article develops a framework for addressing privacy concerns that arise when direct marketers utilize consumer information. It does so by identifying the underlying dimensions of the privacy construct and examining the relationships between those dimensions and direct marketers’ consumer information practices. This approach not only helps identify situations when privacy matters, but suggests productive strategies and tactics for alleviating consumer concerns related to the use of individual-level consumer information.
Chaotic phenomena in an oscillator controlled by DC current pulse
Authors: Inaba Naohiko , Saito Toshimichi , Mori Shinsaku
Published: July 2007

Chaos is a general term for irregular phenomena appearing in deterministic systems which can be represented by differential or difference equations, and it has been studied widely in various fields of natural science. Chaotic phenomena have long been known to occur also in nonlinear electrical circuits. The proof for the generation of chaos, however, is insufficient and circuit experiments are not satisfactory. This paper proposes a chaos generator with which chaos generation can be verified and its confirmation by circuit experiments also is possible. The circuit is constructed from a negative resistance LC oscillator and dc current pulse source. Also, when the amplitude exceeds a certain value, a current pulse of the opposite direction is added, thereby controlling the amplitude. For the analysis a mapping method is used and its Poincaré map is derived strictly as a one‐dimensional mapping having a form similar to the Logistic map. Using this map, such phenomena as period doubling bifurcation, chaos, islands and windows, that are generated in the circuit can be explained. In addition, these phenomena are confirmed experimentally.
Synthesis of single‐amplifier switched‐capacitor filters
Authors: Hayahara Etsuro , Suzuki Takao , Kadowaki Seijiro
Published: July 2007

In the monolithic IC switched capacitor filters (SCF) it is desirable to use as small a member of operational amplifiers (OPA) as possible to save the chip area. This paper presents a circuit configuration of single‐OPA SCF. In the synthesis, a given transfer function is realized by active RC circuits containing ideal phase inversion transformers and then the RC circuits portion is replaced by equivalent SC networks. The characteristics of the realized SCF are sensitive to element variations and its application should be limited to transfer functions of the second to third order with a relatively low Q. High‐order transfer functions may be realized with a relatively small number of OPA's by the cascade realization with this configuration and biquad sections.
Input regulation control based on periodical monitoring using call gapping control
Authors: Fukuda Akira
Published: July 2007

This paper considers input regulation control based on periodical monitoring using call gapping control in a finite‐capacity queueing model. Two Poisson streams arrive at a system, and one of the streams is controlled to enter the system as follows. The system is monitored at periodical epochs. Thus when the number of calls in the system at the beginning of each interval exceeds a threshold, call gapping control which adjusts the call arrival interval is activated during that interval. The state equations of this control are established both for transient and steady states, and various evaluation measures are derived. Call gapping control, no‐control, and call reject control (all low‐priority calls are rejected) are compared through numerical examples and as a result, the following points are clarified.

As for the transient state, the oscillation observed in the control and traffic characteristics of the call reject scheme, can be suppressed by the introduction of call gapping control.

As for the steady state: (i) call gapping control is effective because the loss probability and the mean waiting time are reduced compared with the no‐control case; (ii) the processing volume for the regulation control is reduced in the proposed control compared with call reject control, but an extraprocessing for call gapping control is needed; and (iii) the proposed control scheme becomes effective with the monitoring interval from the viewpoint of protecting high priority calls.
Identification of impulse response by use of smooth input signals
Authors: Adachi Shu‐Ichi , Ibaragi Masahiro , Sano Akira
Published: July 2007

Among the many identification methods of impulse response of linear discrete system, the recursive least squares method is well known because of its ease of handling and excellent convergency. This paper analyzes why the least squares estimates of an impulse response sequence degrade in convergency when one utilizes smooth input signals for identification and the number of data is finite. It also presents an effective identification method even under such a condition. The magnitude of the eigenvalue of the correlation matrix of input signal is adopted as a quantitative index of input signal smoothness and it is demonstrated that small valued eigenvalues increase the mean squares error of least squares estimate. Using the idea of eigenvalue expansion, we also present a new online identification method which truncates small eigenvalues associated with the input autocorrelation matrix. It is shown that the optimal number of eigenvalues can be theoretically determined in consideration of the tradeoff between the parameter error due to observation noise and the parameter error due to the truncation of small eigenvalues. Moreover, by recursively estimating the eigenvalues and the eigenvectors using the power method, the proposed method is generalized to a recursive estimation method to evaluate the estimate at each time instance. By also recursively updating the optimal number of eigenvalues, the proposed method is shown to have an excellent convergency through numerical examples compared to the conventional recursive least squares method.
A method of yield analysis for analog–integrated circuits using spherical surface random numbers
Authors: Jyo Yoichi , Ikeda Hiroshi , Minamoto Suemitsu , Kojima Yoshiaki
Published: July 2007

This paper considers the analog‐integrated circuit in which the element values are correlated with each other, with the deviations following the n‐dimensional normal distribution. A computation method for the yield is proposed. In the method, the deviation of the element value is decomposed into the magnitude and the direction by a transformation of variables. Then only the direction is simulated using the unit spherical surface random number. For each random number, the yield is calculated by the integration of the probability density in regard to the magnitude in the acceptable region determined from the design specification. The final expression for the yield is given in the form of a finite series, which is suited to the computation by a computer. The determination of the acceptable region is discussed. The statistical error in the proposed method is compared with that of the general Monte‐Carlo method, demonstrating that the yield calculation with a high accuracy can be realized by the proposed method. Various improvement techniques for the efficiency in the Monte‐Carlo method are also applicable to the proposed method, and the method is a useful means for the yield calculation in a large‐scale integrated circuit.
An identification method of nonlinear systems by volterra series
Authors: Ichikawa Satoshi , Yamamoto Masanori , Nishigawara Yasuhiro
Published: July 2007

Numerical models whose input‐output relations are expressed by Volterra series, are used to identify nonlinear systems from observed set of inputs and outputs according to given evaluation criterion. Parameters of systems to be identified are Volterra kernels of various orders. Since these kernels are multivariable functions, considerable calculation and memory capacities are required for identification. This paper presents a method without Volterra series which are multivariable functions for identification and output estimation. Our identification method follows the report by Hsieh; the evaluation function is expressed using inner products in Hilbert space, employing operators from fixed input and the Hilbert space to which outputs belong. Next, the Volterra kernel of each order is regarded as a mapping from adjoint space, and the optimization is done for one variable function in adjoint space. The computing method is as follows: the problem in Hilbert space is replaced by a problem in a finite‐dimensional vector space by discretizing the time axis, the orthogonal vector system is obtained, and the optimization by one‐dimensional time sequence is done. Afterward, it is shown that the output estimation can be done for other inputs without obtaining Volterra kernels which are multivariable functions, by using the adjoint solution obtained as described in the foregoing, and constructing its computer algorithm.
A preemptive packet transfer scheme with virtual cells in a long packet
Authors: Watanabe Naoya , Hirano Miki , Kobayashi Masayuki , Yukimatsu Ken‐Ichi
Published: July 2007

In heterogeneous packet‐switching systems that handle packets of various sizes, such as short packets for voice and long packets for image or video, resource occupation by long packets causes an intolerable transfer delay of short packets. To avoid this problem, we propose a preemptive packet transfer scheme, where a long packet, composed of a number of virtual cells, can be preempted by short packets only at the end of each transferred cell. First, this paper analyzes the relationship between the transfer delay of short packets and cell size. Next, a division process for a long packet necessitated by short packet arrival is formulated. Then the amount of long packet processing and long packet transfer overhead are calculated. Finally, a design method for the proposed scheme is discussed and a packet format example for this scheme is proposed.
A fast algorithm of running fourier transform
Authors: Kamei Hiroyuki , Harada Tetsuya , Kawarada Hiroshi
Published: July 2007

A short‐time Fourier transform can be derived by low‐pass filtering of the product of an input signal and exp(j2°ft). According to this method, called the Running Fourier Transform (RFT) in this paper, running power spectra with arbitrary center frequencies and arbitrary Q values can be obtained.

This paper proposes a fast algorithm of discrete RFT (FRFT). In the FRFT, a first‐order lag system is adopted as the low‐pass filter (LPF), and by approximating the impulse response of the LPF with a step function, the amount of multiplications is reduced. The calculation of the complex exponentials is omitted by referring to a table of sin(2°k/K) (k =0, …, K).
Identification of transfer function model in consideration of III‐conditioning
Authors: Adachi Shuichi , Izumisawa Tooru , Sano Akira
Published: July 2007

Often in the identification of the transfer function of a discrete‐time system, the least‐squares estimation does not work well if the system has a pole near z =1, even if the input signal is white sequence. This is because the output correlation function has a small decay, making the corresponding normal equation ill conditioned. This paper proposes an identification method to ameliorate the ill condition of the correlation matrix for such a system. In the proposed method, the identification model is rewritten so that the difference of the output signal is represented explicitly, providing a matrix transformation for the parameters to be identified. The method prepares, for the n‐th order system, n identification models with the highest order (L) being from 0 to (n‐1). The least‐squares estimation is performed for the identification models, and the values of the evaluation functions obtained by the estimations are compared. Then the estimation minimizing the evaluation function is adopted; L determined by the proposed method is related closely to the number of poles near z =1, which is the cause of the ill condition. This situation is examined by computer simulations.
Design of narrowband FM receiver with delay‐flat IF filter for mobile radio communication
Authors: Shimizu Isao
Published: July 2007

This paper discusses the design of the IF filter for the mobile communication receiver, realizing narrowband and low‐distortion FM transmission characteristics. In the traditional mobile communication system with 25‐kHz channel spacing, a Chebyshev IF filter with a steep stop‐band roll‐off has been employed to prevent interference from adjacent channels. If the same design is applied to the narrowband mobile communication system with 12.5‐kHz channel spacing, the linear distortion due to the IF filter increases the demodulation distortion. First, this paper derives the expressions for the demodulation distortion and the adjacent channel selectivity in the narrowband FM transmission system, using the TBT filter as the model for the receiver. Then, based on the result, the condition for the narrowband IF receiver filter is derived to realize the low distortion and the required adjacent channel selectivity. Finally, a receiver was constructed experimentally on the breadboard, and it was verified that the theory and measurement are in good agreement.
Traffic analysis for token ring systems with limited service
Authors: Kimura George , Takahashi Yoshitaka
Published: July 2007

The token ring system is one of the typical LAN systems. In LAN, several kinds of traffic with different properties occur in bursts. The analysis has not been made for the case where the calls arrive in batch following the general distribution (GIx input). In the actual system, the buffer capacity is finite, and the analysis must consider such a property. This paper considers the asymmetric (i.e., the arrival process and the service time distribution are different for different stations) and single‐limitation (i.e., when the token arrives, only the first call is served) GIx/G/ 1 token system (where the suffix [X] indicates the batch arrival). The first half of the paper discusses the case where the buffer capacity of the station is infinite. The diffusion approximation is proposed using the elementary return as the boundary condition, and the quantitative expressions are given for the call distribution and mean waiting time for each station. The second half of the paper discusses the case where the buffer capacity in each station is finite. By combining the diffusion approximation used in the first half and the iteration, the blocking probability and the mean waiting time are derived quantitatively. For each case, simulation was made with the result indicating that the proposed approximation is reasonable.
Degradation of antenna pattern by snow accretion on radome
Authors: Shimba Minoru , Sato Kazuhiro , Koike Hiroo , Sato Takashi
Published: July 2007

Sheet radomes are used sometimes to prevent the degradation of antenna characteristics during snowfalls at simple Earth stations for satellite communication. If the snow accretion over the radome is uniform, the antenna has only a slightly lower level of signal reception. However, if the snow accretion over the radome is not uniform, there may be a large attenuation. In this paper we clarified the mechanism of the degraded antenna pattern due to a nonuniform accretion of snow over the radome. In the worst case, the antenna pattern is changed greatly and we showed that there was up to 40‐dB attenuation along the boresight of the antenna. We measured the process of changing the antenna pattern as the snow accretion changed with the passage of time. We clarified these processes.
Characteristic analysis of continuous‐service‐type multipacket transmission with restriction on number of packets in a frame
Authors: Komatsu Masaharu
Published: July 2007

Multipacket transmission can achieve higher transmission efficiency because many packets are inserted into a frame and per‐packet overhead is small. However, in practice, too many packets cannot be inserted into a frame and too long a frame has higher probability of error. Therefore, the number of packets in a frame must be restricted. This paper analyzes the continuous‐service‐type multipacket transmission with restriction on the number of packets in a frame. Also, the distribution for the number of transmission waiting packets is derived along with the number of packets in buffer, z‐transform of the distribution for the number of packets in a frame, transmission efficiency, average queue length, and average packet delay time. From numerical examples, we examine the influence of the restriction on these performance measures.
Packet‐switched network design with constraints on the circuit discreteness
Authors: Kamimura Kunio
Published: July 2007

The packet‐switched network design problem can be formulated as a capacity and flow assignment problem (CFAP). The CFAP of an elementary network consisting of one tandem switch (TS) and n local switches (LSs) has been analyzed, and economical configurations shown in previous papers. This paper extends the study to include cases in which there are constraints on circuit discreteness. A large‐scale network usually employs a hierarchical structure with elementary networks used as structural units. In addition, the most economical structure of an elementary network in a hierarchical network is ascertained.

The first assumption is that circuit speed is restricted to a predetermined discrete number (multiple of unit speed), and either one or no circuit can be installed per link. When the elementary network represents the entire small‐scaled network, economical regions of star, mesh and combined star/mesh are complicated. This is because effective traffic packing to a discrete capacity circuit sometimes yields more economical network configurations. When the elementary network is a structural unit in a large‐scale network, star occupies most of the economical region because a tandem circuit is always installed for carrying external traffic. The second assumption is that circuit speed is fixed. If a number of circuits can take real numbers, combined star/mesh is always the minimum cost topology in which internal traffic is assigned to the direct circuit, and external traffic through a tandem switch is assigned to the tandem circuit. When the number of circuits is a natural number, it is more economical in some cases to assign some part of the traffic to a tandem circuit because of the integrity of the number of circuits.
Design of audiographic teleconferencing terminal
Authors: Kotera Hiroshi , Sakai Yoshinori , Unemoto Kazuo , Arikawa Tomohiko , Tutt Timothy
Published: July 2007

This paper considers the design and experimental result of an audiographic teleconferencing terminal which applies document and telewriting as media for teleconferences via 64 kbit/s transmission lines, in addition to voice. For an effective teleconference, it is desirable that the terminal realize common visual space and have a paperless facility. First, this paper shows that distributed memory allocation is appropriate to the file configuration and proposes a document retrieval method which uses visual information. Also input/output function and display function suitable for teleconferencing terminals are discussed. Next, human interface which is suitable for teleconferencing terminals is discussed, and a key design pattern and its operational characteristics are shown. Finally, the experimental result of a fabricated prototype is shown.
Performance evaluation for spread‐spectrum multiple‐access communication systems
Authors: Nishida Takeshi , Miyahara Hideo
Published: July 2007

The performance of the spread‐spectrum multiple‐access communication system is analyzed assuming that channel access from each terminal (station) is random. By distinguishing the retransmission traffic load from the freshly originating traffic load, a more accurate formula for message delay can be derived. By comparing the performance between this communication system and the FDMA, this system is shown to have higher usage efficiency of the channel bandwidth. Moreover, the processing gain optimizing the system performance is obtained as the function of the mean offered load. Using this fact, we consider the group random access scheme where all terminals are grouped according to their utilization forms if possible. Then each group uses the separate channel whose bandwidth is determined in accordance with the offered load, and its performance is evaluated.
Analysis of DC‐DC converter using voltage‐resonant switching mode
Authors: Onodera Toshihiro , Masuda Youichi
Published: July 2007

The frequency of switching dc‐dc converters has become higher when their size and weight must be reduced. When a higher frequency is chosen, some related phenomena become problems. These include the increase of the transition loss of the switching, the increase of magnetic energy in leakage inductances of a transformer, and high‐frequency noises. These problems can be solved at the same time by utilizing the resonance‐arc of the switching mode. Notably, a mode in which the applied switching voltage becomes the resonance‐arc is suitable for an increase of the frequency.

This paper analyzes a dc‐dc converter, based on the concept of a class‐E power amplifier which is useful for solving the three forementioned problems. The design of the converter and its characteristics which are useful for understanding the behavior of the converter, are also given. As an inherent characteristic of the resonant switching mode, there is a period in which a part of the energy stored in the resonance circuit returns to its input. By using the duty ratio of the switch in this period, the switching characteristics, such as the transition of a mode and the input/output voltage ratio, were found.
Scattering of electromagnetic plane wave by an infinite plane grating on a dielectric slab for oblique incidence
Authors: Noda Takeaki , Uchida Kazunori , Matsunaga Toshiaki
Published: July 2007

In this paper, the problem of scattering for an obliquely incident electromagnetic wave by a planar grating on a dielectric slab has been analyzed accurately by the method in which the sampling theorem is applied to the Fourier transform. First, by means of the unknown surface current on the planar grating, the Fourier‐transformed functions of the scattered field are given analytically. Next, this current is expanded in terms of weighted Fourier series so that its Fourier transform is given. Finally, the sampling theorem is applied for the purpose of discretization to the relationship for the perfect conductor condition expressed in the Fourier transform domain so that simultaneous equations for the unknown expansion coefficients of the surface current are obtained. By means of the numerical calculations, accuracy of the method is confirmed and the numerical values are given for the transmitted and reflected powers and the surface current.
An image data compression method using extrapolative prediction‐discrete sine transform; in the case of two‐dimensional coding
Authors: Yamane Nobumoto , Morikawa Yoshitaka , Hamada Hiroshi
Published: July 2007

This paper considers the highly efficient coding of the gray‐level image. The extrapolative prediction‐discrete sine transform scheme, which was previously proposed by the authors for the case of one‐dimensional coding, is extended to the case of two‐dimensional coding. In the proposed method, the image is partitioned into square blocks. The correlations among blocks are eliminated by applying the two‐dimensional extrapolative prediction for each block from the restored boundary pixel. The correla‐in the block is eliminated by applying the orthogonal transformation to the prediction errors. In this paper, the correlation function of the image is assumed as the isotropic exponential function, and a two‐dimensional extrapolative prediction method is derived, which can be realized as a simple manipulation. The transformation of the prediction errors is performed by the variable‐separation type two‐dimensional extrapolative prediction‐discrete sine transform, where the one‐dimensional extrapolative prediction‐discrete sine transform is applied to rows and columns. Then the rate‐distortion characteristic is calculated, indicating that the proposed method is useful. It is shown that the proposed method with 4 × 4 block size has almost the same coding efficiency as the discrete cosine transform coding with 16 × 16 block size. A computer simulation was made for the actual image, leading to a result validating the theoretical estimation. The proposed method requires less computation per pixel, compared with the discrete cosine transform coding. The method is especially useful from the viewpoint of hardware implementation, since the block size is as small as 1/16.
Low temperature optical loss‐increase for optical fibers in compound‐filled cable splice closure
Authors: Sasaki Jun
Published: July 2007

To completely protect optical fibers from external water and chemicals, the development of compound‐filled cable splice closure was planned. To this end, the optical loss mechanism at low temperatures in an optical fiber placed in a compound such as epoxy or polyurethane has been investigated. In this paper, as the optical loss generating source in an optical fiber in a compound‐filled cable splice closure at a low temperature, the conventional bucking model of the fiber in a fiber jacket and a new bucking model of the entire jacketed fiber in the compound are considered. It is demonstrated that a phenomenon corresponding to either model appears depending on the kind of compound or jacketed fiber configuration. Next, an experimental equation is derived which shows the relationship between the optical loss and the average rate of curvature of a bucked and sinusoidally bent GI fiber. The optical loss in a GI fiber placed in a compound at a low temperature was estimated and compared with the experimental results. It is found that the experimental and theoretical values agree well even if the compound and the jacketed fiber are replaced. This implies that the two models are valid. Quantitative understanding of the optical loss after bucking is now possible.
Analysis of demand‐assignment schemes with adaptive reservation on bus‐type LANs for integrated communications
Authors: Tokinaga Shozo
Published: July 2007

In the demand assignment scheme on a bust‐type LAN for the integrated communications, the priority using the transmission reservation information is introduced and adaptive channel capacity allocation algorithm is proposed. Data traffic to be transmitted is classified into class 1 (voice), class 2 (data), and class 3 (file). In the usual transmission, higher priority is assigned to class r with smaller r, but in the case where the waiting time of the packet in buffer grows more than a threshold, then the class lower than r obtains a higher priority, instantaneously. As a result, while maintaining the voice packet discard rate below a certain threshold, the excessive delay of the other data traffic can be avoided. This paper proposes adaptive packet transmission prioritization algorithms for each of the four basic DAMA systems–RAM, ADAM, TPAM, and SDAM–and evaluates their performance by numerical calculation. It is shown that by adaptive prioritization excessive waiting time for data and file packets are avoided for the channel speed around 1 Mbit/s.
Improvement on singular value decomposition vector quantization
Authors: Saito Takahiro , Komatsu Takashi , Harashima Hiroshi
Published: July 2007

For high‐efficiency image compression, previously, an SVD (singular value decomposition)‐based coder was developed using vector quantization, called SVD‐VQ. This paper proposes an improved quantization SVD‐VQ scheme. For every input subblock, the SVD‐VQ coder scalar‐quantizes a singular value and vector‐quantizes two singular vectors, separately. The SVD‐VQ decoder reproduces a subblock as the product of these quantization outputs, but does not necessarily produce a reconstruction with the minimum distortion in an image space. This paper develops a quantization scheme where the minimum‐distortion reconstruction is always provided in the original image space and presents its design algorithm. The improved SVD‐VQ shows A/N performance improvement of 0.5 ‐ 1.0 dB over the conventional SVD‐VQ, and is similar in performance to the adaptive DCT (discrete cosine transform) coder.
Evaluations on the common application protocols in osi
Authors: Shiroshita Teruji , Nomura Masayuki
Published: July 2007

For the OSI message exchange protocol, the MHS (message handling system) was recommended in 1984 by CCITT. The implementation of this protocol is being considered by network service enterprises and computer manufacturers in various countries. MHS is constructed as an application of OSI common application protocol. ROS (remote operations service) and RTS (reliable transfer service), specified by MHS, and performing the acknowledgement of send/receive of application data and the interruption/recovery, can also be used in common with other applications of OSI. This paper presents an analysis and evaluation of ROS and RTS from the viewpoint of the number of transmitted/received packets and the transfer time. The relation between the window size and the transfer efficiency in RTS is derived. For the system combining ROS and RTS, the method for controlling the window size corresponding to the response time, as well as the method for setting the session data length corresponding to the interruption rate, are presented. As to the method of combining ROS and RTS, it is shown that a large amount of application data can be transferred in a stable way, even if the interruption rate is large, by applying RTS to ROS.
Experimental studies on fading reduction by four‐direction antenna pattern diversity reception with variable multithreshold switching strategy
Authors: Takeuchi Tsutomu , Ikegami Fumio , Yoshida Susumu
Published: July 2007

An antenna pattern diversity reception system was constructed experimentally as a means to cope with multipath fading in mobile communication, where the four‐direction antenna is used as the diversity branches, which themselves have the fading reduction effect. The variable threshold switching method is employed as the output scheme from the diversity branches. The switching algorithm for the four‐branch multithreshold reception is discussed. From the computer simulation based on the actually measured fading data, the optimal values for the parameters of the branch switching control algorithm are determined.

A field experiment is made using the experimental system, and it is verified that the short‐term fading is improved in the actual multipath environment with the value close to the theoretical value, for the selection switching by four receivers using uncorrelated branches with Rayleigh distribution.
Circuit simulation analysis of power dissipation in the main switch of a forward converter
Authors: Yamasaki Mikio , Murakami Naoki
Published: July 2007

Optimum conditions for the on‐resistance and output capacitance of a power MOSFET used as the main switching element of a single‐ended forward converter are derived by circuit simulation. In the simulation, a device model of the power MOSFET suitable for analysis of a switching power supply is introduced, enabling analysis of the factors contributing to generation of main switch loss. First, the simulation clarifies that the power considered to become a loss in the conventional concept is partly recovered. A new evaluation method is proposed for the main switching loss, taking this phenomenon into account. Next, the main switch loss is analyzed by using as an independent variable the on‐resistance or the output capacitance, which have high device sensitivity to the main switch loss. The results are shown by an equi‐loss diagram. Finally, this diagram is used to derive the optimum on‐resistance and output capacitance with the largest CR product to make fabrication easiest within the allowable main switch loss.
Medical data transmission using mobile satellite communication
Authors: Murakami Hajime , Shimizu Koichi , Yamamoto Katsuyuki , Mikami Tomohisa , Hoshimiya Nozomu , Kondo Kimio
Published: July 2007

A “mobile telemedicine” is attempted where the mobile satellite communication and remote medicine are applied. This study aims at improving emergency care in a ship on the ocean or in an aircraft flying an international route. The problem has several special points which differ from the usual data communication or telemedicine. These points must be overcome to realize the system.

This paper presents first the analysis, investigation and design for mobile telemedicine, and indicates its feasibility. Based on these results an experimental transmission system is constructed. The fundamental transmission characteristics are measured through the satellite link. By the measurement, the threshold of operation for this system for deteriorated C/N0 is determined, and it is verified that even an experimental system can realize a reliability which is sufficient in practice. Then a transmission experiment is made from a ship navigating close to the shore of Japan, and the basic operation as the mobile telemedicine is verified.
Delay performances of tandem stop‐and‐wait arq scheme
Authors: Sugimachi Nobuyuki , Hayashida Yukuo , Yoshida Yoshinori
Published: July 2007

This paper considers the stop‐and‐wait ARQ scheme, which is the most fundamental error control method. The scheme is applied to the satellite tandem communication system composed of two links, and the average transmission delay is investigated.

First, the tandem system with relay retransmission buffer with a finite capacity is considered, and the generating function for the transmission delay is derived. Using the obtained result, the effect of the buffer size of the relay node and the round‐trip propagation delay on the average transmission delay is investigated. It is shown as a result that the tandem‐type stop‐and‐wait ARQ scheme is better also in terms of the average transmission delay than the standard scheme without the relay‐retransmission buffer. The delay improving factor (the ratio of the average transmission delay to the average transmission delay providing the limit of the improvement with the infinite buffer size) is defined. A design principle is proposed for the buffer size, where not only the throughput but also the average transmission delay are considered.
Triplate‐type planar antenna and its array
Authors: Haneishi Misao , Matsui Akinori , Nakayama Masao , Saito Sakuyoshi
Published: July 2007

A new type of electromagnetically coupled planar antenna made of a shielded triplate transmission line is studied and its design method is investigated. To this end: (1) studies are made on the radiation characteristics of the present planar antenna which are important when it is used as an array element. It is found that this planar antenna is sufficiently available as a linearly and circularly polarized array element. (2) The radiation characteristics are studied theoretically and experimentally for the array made of linearly polarized planar antenna elements. It is proven that this type of antenna system can be a useful form for a new type of linearly polarized array. (3) A method of configuration is studied for a circularly polarized array made of this type of planar antenna element. An antenna system is realized which has a broadband characteristic with about 5 percent bandwidth for the axial ratio of less than 3 dB.