bluuebunny/crossref_metadata_2025 huggingface dataset:
Glutathione S‐Transferase, Acetylcholinesterase Inhibitory and Antibacterial Activities of Chemical Constituents of Barleria prionitis.
Authors: Kosmulalage Kalhari S. , Zahid Shamsulhaq , Udenigwe Chibuike C. , Akhtar Sarfraz , Ata Athar , Samarasekera Radhika
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Butyl 2‐(4‐[1.1′‐Biphenyl]‐4‐yl‐1H‐imidazol‐2‐yl)ethylcarbamate, a Potent Sodium Channel Blocker for the Treatment of Neuropathic Pain.
Authors: Liberatore Anne‐Marie , et al. et al.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Neuropathic Pain: Molecular Complexity Underlies Continuing Unmet Medical Need.
Authors: Kennedy Jeffrey D.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
N‐Methyl‐D‐aspartate Antagonists and Neuropathic Pain: The Search for Relief.
Authors: Childers Wayne E. Jr. , Baudy Reinhardt B.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Electronic Structure and Bonding in Actinyl Ions and Their Analogues
Authors: Denning Robert G.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Heavy Fermions: Electrons at the Edge of Magnetism
Authors: Coleman P.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Phase Field Modeling of Phase Boundary Shape and Topology Changes Due to Electrochemical Reactions in Solid and Liquid Systems
Authors: Powell Adam C. , Pongsaksawad Wanida , Pal Uday B.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Main‐Chain Organometallic Polymers: Synthetic Strategies, Applications, and Perspectives
Authors: Williams Kyle A. , Boydston Andrew J. , Bielawski Christopher W.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Metalloid Group 14 Cluster Compounds: An Introduction and Perspectives to this Novel Group of Cluster Compounds
Authors: Schnepf Andreas
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Photoinduced Valence Tautomerism in Co Complexes
Authors: Sato Osamu , Cui Aili , Matsuda Ryotaro , Tao Jun , Hayami Shinya
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Pyrrolo[2,1‐b]thiazoles
Authors: Tverdokhlebov Anton V.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Spiro Compounds for Organic Optoelectronics
Authors: Saragi Tobat P. I. , Spehr Till , Siebert Achim , Fuhrmann‐Lieker Thomas , Salbeck Josef
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Catalytic Asymmetric Hydrogenation of Heteroaromatic Compounds, Indoles
Authors: Kuwano Ryoichi
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Total Syntheses of FR901464
Authors: Koide Kazunori , Albert Brian J.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Artificial Nucleobases for Hole Transport
Authors: Tanaka Kazuo , Okamoto Akimitsu , Saito Isao
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
New Insights into the Oxidative Electrochemistry of Vitamin E
Authors: Webster Richard D.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
The Organic Chemistry of Silver Acetylides
Authors: Halbes‐Letinois Ulla , Weibel Jean‐Marc , Pale Patrick
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Acylketenes
Authors: Kollenz G. , Ebner S.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
The Chemistry and Biology of Cyclotides
Authors: Craik David J. , Cemazar Masa , Daly Norelle L.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Sulfa Drugs as Model Cocrystal Formers
Authors: Caira Mino R.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Final Report on the Safety Assessment of Polyethylene
Authors: Anon. Anon.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Practical Applications of Computational Studies of the Glycosylation Reaction
Authors: Whitfield Dennis M. , Nukada Tomoo
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Old Materials with New Tricks: Multifunctional Open‐Framework Materials
Authors: Maspoch Daniel , Ruiz‐Molina Daniel , Veciana Jaume
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
HPLC Separation of Amino Acid Enantiomers and Small Peptides on Macrocyclic Antibiotic Based Chiral Stationary Phases
Authors: Ilisz Istvan , Berkecz Robert , Peter Antal
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Adaptive bandwidth management in ATM networks
Authors: Dziong Zbigniew , Montanuy Olivier , Mason Lorne G.
Published: July 2007

A framework for adaptive bandwidth management in ATM based networks is proposed. It is based on a layered approach which includes bandwidth allocation to virtual networks. The central concept of this approach is adaptive estimation of the effective bandwidth required, by connections carried in the network. To achieve reliable results the estimation process takes into account both the traffic source declarations and the connection superposition process measurements on the network links. This is done in an optimization framework provided by estimation theory. A study, based on a linear two‐state Kalman filter, shows that the proposed approach provides good adaptation to undeclared changes in traffic parameters and that the network performance is significantly improved when compared to the effective bandwidth allocation based solely on the source parameters declarations. These features allow more relaxed source parameter declarations and at the same time permit less stringent source policing. Thus the two bottlenecks influencing bandwidth management in ATM networks can be significantly widened.
Modelling VBR video over networks end‐to‐end using deterministic smoothing at the source
Authors: Shroff Ness , Schwartz Mischa
Published: July 2007

Video traffic is expected to become increasingly important with the large scale deployment of broadband ISDN. In the literature, it is suggested that smoothing variable bit rate (VBR) video traffic1,2 before transmitting it onto the network would help reduce the probability of cell loss. In this paper we show why deterministic smoothing at the source approximates the minimum achievable loss over the network end‐to‐end of all possible smoothing schemes. Furthermore, we develop a powerful yet simple analytical technique that can efficiently calculate the loss probability at any point in a network carrying video traffic. We validate our analytical results using traces of actual video segments. The results can be used for admission control and traffic management. We find that in the case of highly correlated traffic such as motion JPEG video, the way to control loss is to ensure that the fraction of time the arrival process exceeds the service process is small. We also find that for such sources increasing the buffer size only marginally decreases the loss.
A distributed media access protocol for packet radio networks and performance analysis. Part 2: Network set‐up time and data rate
Authors: Pond Lawrence C. , Li Victor O. K.
Published: July 2007

In this, the second part of a two‐part paper, the required time for establishing a mobile packet radio network using the virtual circuit and time division multiple access protocol developed in Part 1 is analysed. Tools are developed to determine the virtual circuit and network set‐up times in terms of the channel bandwidth allocated to establish and maintain the network. The tools are then extended to include the effects of user mobility. Then these results are combined with the network capacity results of Part 1 to analyse the trade‐off between the data rate and set‐up time of the network. Next a hierarchical architecture is proposed and the network data rate versus set‐up time trade‐off of this architecture is analysed using these tools. This architecture is shown to both provide a higher data rate and establish faster than flat networks of the same number of nodes.
Evolutionary architecture for an all‐services ATM access network
Authors: Stein K. U. , Straten G. V. D. , Moehrmann K. H. , Lutz K. A. , Geyer S.
Published: July 2007

This paper presents a flexible concept for a broadband subscriber access network which minimizes investment costs by predominantly using the existing network infrastructure. The target network may consist of either a coaxial tree‐and‐branch structure or symmetrical copper pairs to the subscriber, and is connected to the central head station with the aid of optical feeder lines which can be implemented or enhanced by a passive optical network (PON). In the event of an increase in bit rate requirements, the coaxial network can be expanded by dividing it into smaller, optically fed subnetworks or by supplementing it with optical overlay systems. Flexibility, expandability and low costs are achieved through the standard ATM format implemented for the signals of all interactive services down to the network termination units on the subscriber side. Those signals are transmitted in the coaxial network in frequency bands above the CATV band in accordance with a multiple of the CATV channel width to ensure that the modulation and demodulation is implemented in a cost‐efficient manner while providing ‘bit rate on demand’ for a suitably high number of subscribers. Separation of the network termination unit from the customer premises equipment enables a flexible, cost‐efficient subscriber configuration to be selected, existing domestic wiring to be used and several completely different subscriber terminals to be simultaneously connected.
A method for determining the absorbing clamp position in the detection of power line induced noise
Authors: Nagasawa Yoji , Sato Risaburo
Published: July 2007

Numerous methods have been prescribed to measure the radiation noise from electonic apparatus in different bands over a wide frequency range. For the range from 30 to 300 MHz, in one of the methods the radiation noise is coupled to the power line and the resulting noise power propagating along the power line is measured by an absorbing clamp. However, in this method, the detected noise power depends heavily on the clamp position on the power line resulting in a very unstable measurement. In particular, in the case of click noise the determination of the clamp position is very difficult. In this paper we propose to capitalize on the noise current standing wave along the power line. Thus, by bypassing the high‐frequency noise current to the ground, a stable standing wave can be generated without being affected by the impedance variation on the power line side and hence the proper clamp position on the power line can be determined accurately, which has been confirmed experimetnally. A simple frequency was used in the experiment but from the impulse response of the measurement system the proper clamp position can be determined for impulsive noise as well, as in the case of a single frequency. Measurement of click noise using an absorbing clamp in the measurement system with a household iron as a device under test confirmed that the maximum detection position agrees reasonably well with that predicted theoretically.
A class of limit‐cycle‐free floating‐point digital filters with minimum roundoff noise
Authors: Akamine Masami , Higuchi Tatsuo
Published: July 2007

For state‐space digital filters using floating‐point arithmetic, the roundoff error and the coefficient quantization error are analyzed in the time domain. The problem to synthesize a digital filter with minimum coefficient sensitivity and minimum roundoff error is formulated. The synthesis method for digital filters with minimum coefficient sensitivity is proposed, and the algorithm for finding the optimum order of additions is derived. The results of analysis are in good agreement with the results of simulation.
Effects of error propagation on the performance of coding schemes for still pictures
Authors: Unno Takehiro , Takahashi Kenichi , Tasaka Shuji
Published: July 2007

This paper investigates the effects of noise‐induced transmission errors on the performance of compression coding methods for still pictures. The following four coding methods are considered: (1) adaptive cosine transform coding; (2) DPCM coding; (3) adaptive block coding; and (4) vector quantization coding. First, the relations among the bit error rate, signal‐to‐noise ratio (SNR), and code lengths by these coding methods are compared in the case of transmission without error control. Adaptive cosine transform coding and adaptive block coding require control information for adaptivity; therefore, they are investigated with and without transmission errors in the coding control information. Further, transmission with error control is studied for sending control information. Considering the error control methods, both automatic repeat request and forward error correction are considered. In these cases SNR deterioration by transmission noise beyond error correction capability and the amount of additional data required for error detection/correction or retransmission are examined. BCH codes are used for error detection and correction.
An analysis for interdeparture process of a polling system with single message buffer at each station
Authors: Takine Tetsuya , Takahashi Yutaka , Hasegawa Toshiharu
Published: July 2007

This paper considers the polling system with the single message buffer at the station. Most of the past studies on the polling system have been concerned primarily with the mean delay and the mean throughput. To analyze the multihop system which appears in the interconnection of information networks, however, the interdeparture process in the system must be analyzed. This is because the output process in each system is related closely to the input process in other systems. From such a viewpoint, this paper analyzes the interdeparture process in the polling system with the single message buffer at the station, and presents the Laplace‐Stieltjes transform of the interdeparture time distribution. Using the obtained result, numerical examples are presented, indicating some interesting results concerning the coefficient of variation of the interdeparture time distribution.
Development of the transmission equations using electromagnetic field theory on a transmission line coupled with external fields
Authors: Amemiya Yoshifumi , Tokushige Kango
Published: July 2007

Researchers in the past initially assumed the existence of transmission line equations in deriving the transmission equations for two parallel lines which are exposed to the external field. They used a method which mixed the theory of electromagnetic fields and the circuit theory. In this paper we do not initially assume the existence of the transmission line equations, nor do we mix the circuit theory. We established one equation of the vector potential on the line from the viewpoint of the field theory. After we introduced the concept of line voltage, it was divided into one pair of two equations concerning the vector potential and the line voltage. Under the assumption that line diameter is sufficiently small, we obtained two equations as one pair for the line current and the line voltage together with the representation of the series inductance and the parallel capacitance as coefficients. These equations are the same as those derived by previous researchers. Strictly speaking, the line current is obtained as the solution of an integral equation. This solution consists of the solutions of the transmission equations and many strongly decreasing higher‐order terms according to the distance because of nonzero diameter of the line. However, higher‐order terms are in practice, negligibly smaller than the former solutions (for example, of the order of 10‐3). Therefore, the forementioned transmission line equations are considered to be correct with a good approximation.
Studies on subscriber line equalizer using decision feedback equalizing circuit
Authors: Tamaki Norio
Published: July 2007

The metallic subscriber line is composed of the cascade connection of cables with different core radius and the openended branch line called bridge‐tap. Previously, the line equalizer for such a line has been constructed by combining the f equalizer, which has the equalization function for the single core cable, and the DFE circuit. The DFE circuit has a structure suited to LSI implementation, but has a problem in that a decision error propagates to succeeding bits, since the result of the decision is fed back as the compensation waveform for the intersymbol interference. This paper proposes a line equalizer based on the DFE circuit, which includes the DFE pre‐equalizer to stabilize the DFE circuit. The design principle is presented. More precisely, the error propagation in the DFE circuit is analyzed. Combined with the analysis of the subscriber line characteristics, the required characteristics for the DFE equalizer are shown. Then a discussion is made on the number of taps in the DFE circuit, which determines the scale of the DFE circuit. Finally, a design example is presented for 320 kbit/s TCM transmission‐line equalizer based on the design method presented. By experiment, the desired characteristics are verified.
High reliability FRP strength member for nonmetallic optical fiber cable
Authors: Kuwabara Nobuo , Koga Hiroaki
Published: July 2007

It is possible to employ nonmetallic optical cables in regions with strong electromagnetic disturbances such as the vicinity of railroads, etc. However, the method to evaluate the reliability of the strength members of FRP in these cables is not yet known. In this paper, experimental investigations are carried out on bending strain characteristics, which is the main problem in reliability of FRPs. The method to estimate the lifetime of FRP with known temperature and humidity conditions and under fixed bending radius is described. Next, using this method, experiments on evaluation of FRPs with different comprising materials are carried out. It is indicated that there is a remarkable improvement in reliability by using glass fibers of high strength which are very suitable to be used as highly reliable FRPs in optical cables. As the result, it is shown that by using these FRPs in optical cables, the allowable bending radius of the optical cable is reduced by the factor of one‐half and the modulus of elasticity of the optical cable is increased by a factor of 1.4, compared to the optical cables with previous FRPs.
A design method for cost minimization of highly reliable communication networks
Authors: Tanaka Yoshiaki , Akiyama Minoru , Wallstrum Bengt
Published: July 2007

In designing a highly reliable nonhierarchical communication network, it will be more practical if not only the required number of disjoint routes is ensured, but also the cost is minimized. Under certain assumptions, the communication network cost can be evaluated by a simple matrix calculation. The branch cost and its associated switching node cost are evaluated by the sum of the fixed cost and the traffic proportional cost. It is assumed that the traffic is carried through a minimum cost route in a normal state and, based on this assumption, the traffic offered to each branch is calculated. Then the communication network cost for given nodes, branches, and traffic matrix, is obtained by matrix calculation. Moreover, the approximate formula, which has already been proposed, is used to calculate the number of disjoint routes. Therefore, the minimization of the network cost under the constraints of the number of disjoint routes can be done by matrix operation. Since the matrix calculation is especially suitable for a supercomputer, relatively large‐scale networks can be designed systematically by the proposed design method.
Multimode‐fiber‐type optical directional coupler for otdr using acoustooptical deflector
Authors: Horiguchi Tsuneo , Nakazawa Masataka , Tokuda Masamitsu
Published: July 2007

The optical directional coupler is one of the key devices for an optical time domain reflectometer (OTDR). In this paper, an optical directional coupler employing an acoustooptical deflector was used to investigate the backscattered light from a multimode fiber. First, the fundamental characteristics of an acoustooptical deflector, diffraction efficiency, and rise time were evaluated. For this evaluation, the theoretical value of the diffraction efficiency was obtained by the ray tracing method. The length and height of the transducer in an acoustooptical deflector were optimized. The relationship between the rise time of the acoustooptical deflector and the focusing distance of a lens in the collimator was also obtained. Using the results, an optical directional coupler was designed and fabricated. Finally, the optical directional coupler was built in an OTDR and excellent performance was confirmed.
Polarization noise due to vibration of a birefringent singl‐mode fiber: Computer simulation analysis and experiment
Authors: Imai Masaaki , Ohtsuka Yoshihiro , Terasawa Yoshiaki
Published: July 2007

In optical birefringent fiber links with misaligned joint section, forced vibrations by a loudspeaker will cause the polarization state to fluctuate. If the output light from the fiber is detected through an analyzer, the “polarization noise” can be observed. As a quantitative measure, the mean value of intensity fluctuations to standard deviation, that is, the signal‐to‐noise ratio (S/N ratio), is introduced. S/N ratios are measured by varying the incident angle to linearly polarized light (α) and misalignment angle of principal axes of fibers (). If S/N ratios of various birefringent fibers (elliptical jacket, Bow‐Tie and Panda types) with α = 0 and α = 90° are compared, it is confirmed that the latter could be reduced by about 15 dB. As the degradation of the S/N ratio due to polarization noise, the intensity fluctuations of the propagating light are formulated under the assumption that the polarized coupled mode is generated at one place inside the fiber. Computer simulations are carried out to analyze fluctuation of extinction ratio and phase difference of normal modes for Gaussian probability distributions. Consequently, the analytical results are in good agreement with experimental ones of S/N ratio, for proper mean value and standard deviation. Therefore, using this method, it becomes possible to estimate the fluctuation parameters.
Burst multiplexing method of multimedia signals by commuication terminal
Authors: Sakai Yoshinori
Published: July 2007

This paper proposes a new multimedia burst multiplex system for efficiently multiplexing such multimedia signals as speech and image on the digital channel. The performance is analyzed by approximation. The signals for each medium are encoded, put into packets, and stored in the buffer memory. The controller shared by media monitors the number of packets in the buffer memory as well as the maximum waiting time. The results are weighted for evaluation; and, according to the proposed rule, the packets are sent out to the line. By an approximate analysis, the proposed system is compared with FIFO and another system with priorities. It is seen that the proposed system, in terms of the performance, is in between FIFO and the priority systems. It can control and prioritize according to the property and state of the media, and is suited to multiplexing of media with various properties.
Loss probability characteristics of two‐dimensional traffic
Authors: Ohmae Yoshitsugu , Fukuda Mitsuko
Published: July 2007

In multimedia telecommunication, multidimensional traffic is formed, where signals such as voice, data and image exist on the same system. It is known that the traffic characteristics are different in such a case from those of the one‐dimensional traffic based on telephone calls. However, no quantitative study has been made on such traffic characteristics. This paper considers the two‐dimensional traffic of the loss system where two classes of calls exist: basic and wide‐band. The loss characteristics are derived and provide a guide for the design including wide‐band calls.
Star wiring network for premises
Authors: Nara Shin‐Ichi
Published: July 2007

It is known by experience that a single‐layer star wiring network is suited for the design of premises distribution network with a small number of terminals. On the other hand, it is anticipated that the star wiring network with more than one layer will be better when there are a large number of terminals. In the design of the star wiring network with more than one layer, there are a number of parameters to be determined, e.g. the number of nodes, the placement of nodes, and the reduction of cables. However, no method has been presented by which the optimal distribution network configuration can be determined. This paper aims at the determination of the optimal configuration for the premises distribution network with two‐layer star structure. A model is presented for the modified two‐layer star wiring network, including anew the tandem connection. The cost function is derived, and the network configuration is determined to minimize the cost function. As a result, parameters which are important in the design can be determined for the practical rectangular area, where the important design parameters such as the number of nodes, the placement of nodes and the necessity for reducing the cable, are determined from the given area size and the number of terminals.
Study of multidimensional coded modulation in land mobile radio communication
Authors: Kato Eiji , Sasaoka Hideichi
Published: July 2007

A high reliability in communication is required in data transmission, such as personal computer communication and facsimile, in the digital land mobile communication. One means to cope with this problem is the coded modulation.

This paper discusses the multidimensional coded modulation which is one such coded modulation method. Little consideration has been given to the application of this method to land mobile communication. In this study, 16 QAM is employed, applying the fading distortion compensation to the modulation method. The interleaving method is combined, and the bit‐error rate of the multidimensional coded modulation system under the fading environment is investigated.

The four‐, eight‐, and 16‐dimensional cases are investigated by computer simulation, and a gain of approximately 3 dB is indicated for the eight‐ and 16‐dimensional cases. The reason for such a small improvement is due to the unbalance of the error‐rate performance in the coded symbol block. From such a viewpoint, the bit‐error rate is analyzed by dividing the bit sequence in the symbol block into three parts, considering only the eight‐dimensional case. As a result of the effort to reduce the unbalance of the bit‐error rate performance under fading, the improvement of approximately 6 dB is realized for the bit‐error rate of 103, thereby increasing the performance improvement.
620 Mbit/s high‐speed switching equipment design
Authors: Hiraide Kazuhiro , Murakami Kenjiro , Otsuka Yoshihiro
Published: July 2007

This paper considers the design method to realize the high‐speed switching equipment at the level of 600 Mbit/s, which can switch the PCM‐coded NTSC and HDTV signals. In the switching of the high‐speed signals at the level of 600 Mbit/s, the equipment must be designed at the level close to the performance limit of the devices and implementation, which are generally available at the present stage.

A method is provided which can estimate the upper limit of the switching equipment performance at the stage of design by relating the performance of the devices. More precisely, the single‐stage space‐division switch is analyzed, and it is shown that the 620‐Mbit/s switching equipment can be realized by applying ECL with the transmission delay of some 0.4 ns and providing the retiming for each board. The feasibility is demonstrated by an experimental setup and the usefulness of the proposed method is indicated. By the proposed method, it is also possible to estimate the number of parallel bits, when the parallel switching is planned using low‐speed components. The maximum operating speed is discussed also for the switching using retiming methods.
ATM switching network with route‐associated buffers and its traffic‐handling characteristics
Authors: Han Chimoon , Akiyama Minoru
Published: July 2007

Asynchronous transfer mode (ATM) switching is studied widely as the switching method in the broadband ISDN and numerous switching methods have been proposed. In most of those methods, the deterioration of the throughput due to the internal collision of the cells is prevented in the switching network by a complex control protocol or by increasing the internal speed. In the highspeed broadband switching system such as ATM, however, it is desirable for the system that the structure and the control be simple, the internal speed not be increased, and the highly efficient switching network be realized with a nonblocking property.

This paper attempts to satisfy the forementioned requirements and proposes the route‐associated buffer system in which the buffers are provided corresponding to the input and the output route, while improving the efficiency of the use of the buffers. The network configuration and the traffic control process are presented.

In the traffic analysis, the poling model is defined, where the number of cells to be taken out from the individual buffer is adjusted according to the number of waiting cells. The traffic processing performance of the switching network is analyzed using the approximate method of analysis for the cyclic multiple queues. The usefulness of the method is shown by numerical analysis and simulation.
Direct sequence/spread spectrum communication systems sending with reference pn sequence for power line data transmission
Authors: Tachikawa Shin‐Ichi , Marubayashi Gen
Published: July 2007

This paper proposes a novel direct sequence/spread spectrum communication system for use in power line data transmission where the transmission characteristic varies largely and rapidly. In the proposed system, two similar PN sequences are used, one of which is loaded with data and the other is used as a reference PN. Waveform distortion during transmission can be cancelled out by an appropriate process utilizing two PN sequences. Data can be recovered as the sign of correlations between two PN sequences at the receiver. Results of computer simulation show considerable improvement in the data error rate over the conventional DS/SS system.
Antenna performance evaluation with reflector distortion data using Akima's interpolation scheme
Authors: Itanami Takao , Kobayashi Takehiko , Ohata Kohei
Published: July 2007

As multibeams begin to be used in satellite communication, the satellite‐borne antennas have become larger. Hence, development of an antenna with a large aperture with a lightweight and high surface accuracy is being carried out. Unlike conventional small antennas, this antenna experiences a large thermal deformation due to severe environmental conditions on the geostationary orbit. In addition, a large deformation due to gravity occurs in the performance confirmation test on the ground. In the development of such a large antenna, it is indispensable to develop a method to appropriately evaluate the change of electrical performance by the deformation.

In this paper, an antenna characteristic computation method is presented which can compute the radiation characteristics of the reflector surface for arbitrarily deformed shapes. The present method uses Akima's interpolation scheme for the deformation data so that data needed for computation of the radiation characteristics are obtained and highly accurate computations are realized.

The analysis results of the deformation of the reflector surface of a reflector by a general‐purpose structural analysis program (NASTRAN) is linked to the present computation method so that the variation of the antenna electrical performance by deformation is obtained and the results of the present method are presented. Further, it is shown that the measured antenna characteristics and the numerical results of the electrical performance by the reflector surface measurement data agree well. Hence, the present antenna characteristic computation method is extremely useful for the evaluation of the antenna characteristics.
Wide‐band characteristics of fin ferrite electromagnetic wave absorber
Authors: Naito Yoshiyuki , Mizumoto Tetsuya , Nose Hiroyuki , Takahashi Michiharu
Published: July 2007

Fin electromagnetic wave absorbers are proposed in which the sintered ferrite plates are placed in the direction perpendicular to the electric field of the incident electromagnetic field. By numerical calculations, it is shown that this structure has a broadband reflection suppressing characteristic. The characteristics of the absorbers in terms of the structural parameters of the absorber and ferrite permeability are shown, and it is found that the optimum structure of the absorber for a broadband operation depends on the permeability of the ferrite. Further, by means of the model experiment, the broadband characteristics of the proposed absorber are demonstrated.
Analysis of the pyramid electromagnetic wave absorber‐an approximated model and its application of TE wave
Authors: Anzai Hiroki , Saikawa Makoto , Mizumoto Tetsuya , Naito Yoshiyuki
Published: July 2007

No detailed analysis has been available on the return loss characteristics of a pyramidal electromagnetic wave absorber. Therefore, an approximate analysis method for the pyramidal absorber has not been established in a rigorous sense.

In this paper, the return loss characteristics for the normal incident on the pyramidal absorber are derived by the numerical simulation based on the spatial network method. Also, as an approximate method for the wave absorber that can approximate the obtained results well, a method called the synthesized capacitance model is proposed. By comparison of the numerical results by the two methods, it is found that the approximate results by the synthesized capacitance model provide more accurate results than those by the previous approximate models. Further, by means of the synthesized capacitance model for the normal incidence, the oblique incidence characteristics of the TE wave were computed and the results agreed well with the measured data.
Method of estimating bit error due to lightning surge taking into account arrester operation
Authors: Motomitsu Tamio , Yamane Hiroshi , Hattori Mitsuo , Tokuda Masamitsu
Published: July 2007

The bit errors caused by the lightning surge contain one triggered by the operation of the lightning arrester installed in communication equipment and one caused by the superposition on the signal voltage the lightning surge (transverse lightning surge) appearing between two conductor wires due to the unbalance of the telecom system. In this paper, a method of estimating and evaluating the bit error by simulation (numerical calculation) is proposed in which these two bit errors are taken into account. By means of the proposed method, the average bit error per thunderstorm day by the lightning surge in the subscriber terminal of the AMI bit digital transmission system was derived. It was found that the bit error due to the operation of the arrester is proportional to ‐1.8 power of the operating voltage of the arrester while the bit error due to the transverse lightning surge is proportional to ‐1.8 power of the threshold level. The bit error at the time of appearance of the lightning can be substantially larger than the bit error inherent to the digital transmission system. Further, the relationship between the number of samples used in the simulation and the estimation error was studied. It was found that the adequate number of samples is 50 to 100.
Neural processing‐type optical wavelength division multiplexing demultiplexer using a grating
Authors: Aisawa Shigeki , Noguchi Kazuhiro , Matsumoto Takao , Tsunetsugu Hideki , Yuda Masahiro
Published: July 2007

A neural processing‐type optical wavelength division multiplexing (WDM) demultiplexer (NP‐ODEMUX), which consists of diffraction grating, detector array, and neural network LSI, is proposed in order to improve receiver sensitivity while maintaining flexible demultiplexing characteristics. In previous work, a neural processing‐type optical WDM demultiplexer using a multimode optical waveguide was proposed. This conventional NP‐ODEMUX and the proposed grating‐type NP‐ODEMUX are compared using power penalty calculation simulations. The results show that receiver sensitivity is improved using the proposed grating‐type NPODEMUX.

Also, a standard diffraction grating demultiplexer without neural processing is compared with the proposed NP‐ODEMUX using power penalty and it is shown that the proposed NP‐ODEMUX can demultiplex WDM signals without degrading receiver sensitivity. Next, the results of the demultiplexing experiment for six‐channel WDM signal which has been directly modulated at 150 Mb/s using nonreturn to zero (NRZ) pseudorandom signal by grating‐type NP‐ODEMUX prototype are described. Bit‐error rate measurement for both the conventional diffraction grating demultiplexer and the grating‐type NP‐ODEMUX using neural processing for the unequally spaced WDM signals revealed that the receiver sensitivity can be greatly improved and that it can flexibly compensate wavelength change.
A fair and efficient bandwidth allocation algorithm for high‐speed local area networks
Authors: Saito Tadao , Aida Hitoshi , Kim Byung‐Suk , Aoki Terumasa
Published: July 2007

With the advent of broadband integrated services digital network (B‐ISDN), there is the increasing need for high‐speed multimedia systems also in the area of local area networks (LANs). It is obvious that the conventional systems such as CSMA/CD or token ring cannot cope with those requirements. At present, several new access control methods are proposed for slotted ring (or bus) LANs suited to transmission rates above 155 Mbps.

This paper reviews the characteristics of those methods in a systematic way and proposes a new access control method called distributed reset algorithm (DRA). DRA can provide high throughput while maintaining the almost strict access fairness by using a new control called “access bit control” in addition to the already known window control.
A new access control method based upon frame addressing for distributed access subscriber network
Authors: Saito Tadao , Aida Hitoshi , Kim Byung‐Suk
Published: July 2007

A distributed access network in which the optical fiber is shared among terminals through media access control has been examined as the subscriber part of broadband integrated services digital network (B‐ISDN). In a distributed access subscriber network, unlike peer‐to‐peer communications which can be seen in local area networks, the main traffic flows are between exchange node and terminals. Therefore, a new access control scheme based on this characteristic should be developed. In this paper, a new access control method based on frame addressing is proposed and simulation analysis is performed. Compared with other methods, it is shown that, by employing cyclic reset and back‐pressure mechanism into the access control, a fair and efficient network access can be achieved for various types of traffic.
Transient model of wafer temperature in a furnace for semiconductor fabrication process
Authors: Mokuya Kinji , Matsuba Ikuo , Matsumoto Kuniaki , Yoshinaka Akira
Published: July 2007

The nonuniform temperatures that develop over silicon wafers on insertion and removal from the furnaces used in the oxidation and diffusion processes of semiconductor fabrication are one factor in reduced yields. For example, because of temperature differences in the oxidation process there are thermal stresses and differing thermal hystereses over the wafer surface which degrade the uniformity of the oxide layer formed. The most pronounced temperature differences, occurring when the wafers are inserted into the furnace, develop mainly because of the effect of the boat jig which supports the wafers. Since the heat capacity of the boat is much greater than that of the wafers, during the slower rise in the boat temperature radiant heat exchange with the wafer bottoms keeps the temperature of the bottoms lower than the temperature of the wafer tops, which are almost unaffected by the boat. This transient in the wafer temperature depends on such process parameters as the boat insertion speed, the ratio between the wafer and furnace reactor tube diameters, and the wafer spacing. In order to analyze this temperature characteristic the process is modelled and the results of numerical simulation are compared with experiment. The model for the wafer temperatures inside the furnace is a system of coupled partial differential equations for the mostly radiant heat fluxes of the boat and wafers. With an insertion speed of 2 m/sec, both the experimental data and the model give a maximum temperature difference over the wafer surface of 230°C near the end of insertion, thus confirming the model.
A novel Bi‐CMOS technology with upward and downward diffusion technique
Authors: Sato Kazuo , Shimizu Keiichiro , Nakamura Yutaka , Okas Koji , Nakamura Fumihisa , Kimura Takeji
Published: July 2007

A Bi–CMOS technology with novel upward and downward isolation diffusion is investigated. This new structure permits the simultaneous realization of high‐performance, high–density CMOS and bipolar devices on the same LSI chip, which is necessary for advanced digital and analog circuitry.

Beginning with a preliminary buried diffusion, the upward and downward isolation diffusion technique forms the MOS transistor n‐channel region and the bipolar device isolation regions. Adoption of this technique permits simplification of the fabrication process while using only a thin epitaxial layer (α.5 μm). Thus, very small, high‐performance (fT × 1.5 GHz) bipolar devices are obtained. Further, since the CMOS structure has both n+ and p+ buried layers and polysilicon electrodes, the CMOS devices are very dense and their latchup immunity characteristics are improved (by a factor of 3 over the usual CMOS).
Cmos device model for accurate circuit simulation application
Authors: Sano Eiichi , Kimura Tadakatsu
Published: July 2007

Circuit simulation programs with much higher accuracy than those presently available are required to achieve analog circuits with higher accuracy. For the simulation method which is a factor in determining the accuracy of circuit simulation, a charge‐oriented simulation method has been proposed and utilized effectively. On the other hand, in terms of a device model which is another factor, there has been no current and capacitance model consistent with the forementioned simulation method and available for submicron devices. This paper proposes a submicron CMOS device model which is used in the charge oriented circuit simulation to achieve higher‐accuracy circuit analysis. The features of this model are: (1) continuity of drain conductance at the pinch‐off voltage ensures accurate expression of the drain conductance which is especially important in designing analog circuits; (2) minority carriers in the pinch‐off region are considered to express accurately the current and capacitance characteristics in the saturation region. By comparing the drain current vs. drain voltage characteristics for 0.6 μm and 1.0 μm devices and the capacitance characteristics for a 0.8 μm device reported elsewhere it is shown that the calculated values are in good agreement with the measured values. Thus, our model is confirmed to be applicable to the high‐accuracy design of submicron CMOS circuits.