bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simple OHP equipment for demonstrating centrifugal spherical waves and group of minute articles by using moiré and reversal moiré and their evaluation
Authors: Kitagaki Ikuo 
Published: July 2007

AbstractThis paper describes simple OHP equipment as an aid in the teaching of physics, for example, electromagnetics by demonstrating centrifugal spherical waves and a group of minute articles radially progressing. A Moiré pattern is produced by using two grated transparencies having certain lattices, one fixed, and the other rotated. In this paper, rotating type Moiré patterns are used since they are easy to operate. Each lattice is designed as a function of the propagation velocity of each phenomenon to be demonstrated. The model of the movements of a group of minute articles is used for the divergence in a vector analysis. A reversal Moiré is used for this model. This paper discusses the method of designing the grated transparencies required for these models. Another model for demonstrating the electric force around a dipole is described, formed by overlapping two identical transparencies in a slightly shifted position. It is proven in this paper that this overlapped pattern agrees with the pattern of an electric field formed by a set of parallel lines charged positively and negatively, respectively, and with a homogeneous density. The responses of students to this equipment are analyzed via factor analysis, and the factor axis representing “idea” gains a relatively high mark.
Optimum capacity‐flow assignment problems with respect to fairness in loop networks
Authors: Iwakuma Yoshaki , Tanno Kuninobu , Nakamura Tadao 
Published: July 2007

AbstractConventionally, the problem of capacity‐flow assignment in packet switching computer networks has been considered mainly for the purpose of improving the network performance and the effective usage of the resources in the networks. The problem of the fair allocation of the network resources to each user (fairness) has been investigated little. Because one of the most important purposes of the computer network is that a plural number of users can use the network resources which are arranged dispersively in the network, we must make sufficient study of fairness in the problem of the flow assignment of the packet and the problem of the distribution of the line capacity. However, no clear definition of the fair allocation has been proposed to dare. In this paper, we adopt the “power” (function) as the performance measure and discuss the problem of the network capacity‐flow assignment in which maximized network. power ensures effective usage of networks, and equalized power for each user realizes the fairness. The results of this study provide a new guideline to solve the problem of distributing the resources effectively and fairly. The method in this paper can be discussed generally without limitation of the network topology. However, since the concrete numerical calculation is so complicated, we take loop networks for the object of the analysis.
ϵ‐Kalman filter—a method of signal estimation considering sudden changes of signals
Authors: Arakawa Kaoru , Harashima Hiroshi , Miyakawa Hiroshi 
Published: July 2007

AbstractA digital filter is developed to estimate signals containing discontinuities from observations contaminated with low‐amplitude white noise. Called an ϵ‐Kalman filter, this is a Kalman filter combined with a nonlinear function. It is very effective for signals with known statistical properties. Principles of operation and realization of the filter are discussed. It is compared with another nonlinear filter called an ϵ‐filter also proposed by the authors. Results 01. computer simulations are shown to demonstrate the effectiveness of the new filter. Pictorial examples are also provided.
Clock path phase errors
Authors: Kihara Masami , Takama Tohru , Makino Masatoshi 
Published: July 2007

AbstractThis paper aims at the total design of synchronizing clock phase quality in a master‐slave synchronization network and studies the clock path phase errors. In master‐slave synchronization, reference clock distribution paths are a major source of phase errors. It is useful to examine the phase errors using Time Interval Error (TIE), specified in units of time. In this paper, the TIE of clock paths containing multiplexers, digital transmission lines and digital synchronous terminals is analyzed. Then measurements taken for multiplexers are presented by varying a stuffing ratio. Field data taken for a 7‐link clock path, the longest effective link path in Japan, shows that in practice a TIE of less than 100 ns over a 102 – 103 s measurement period is measured, which agrees well with theoretical data.
Approximation of multivariable linear systems by lower‐order models
Authors: Maekawa Sadao , Hinamoto Takao , Nakamura Yoshinari 
Published: July 2007

AbstractThis paper is concerned with the rational approximation of multivariable time‐invariant discrete‐time linear dynamical systems. An efficient method is developed for approximating given matrix Markov parameters (impulse response) by a low‐order rational function. This is a generalization of the approximation theory reported by Mullis and Roberts, and obtainable by extending their technique for single‐input single‐output systems to multiinput multi‐output case. The parameters of a rational function can be obtained by solving linear equations by means of a recursive algorithm. In addition, the stability of the approximating rational function is always ensured.
Performance of spread spectrum synchronous access communication system by orthogonal sequences
Authors: Zhu Jinkang , Nomura Tamiya , Yamada Takahiro 
Published: July 2007

AbstractIn conventional spread spectrum communication systems characterized by asynchronous multiple access SSRA (spread spectrum random access), interchannel interference is not zero and consequently the number of simultaneously communicable channels is small and the frequency utilization efficiency is low. The near‐far problem is also important. For performance improvement SSSA (spread spectrum synchronous access) systems with orthogonal sequences have been proposed. This paper discusses performance of an SSSA communication system which is based on the use of a set of orthogonal sequences formed by adding +1 to each of the M sequences. Because interference does not exist under the condition of perfect synchronism between channels, it may be expected that the multiple access capability is improved, the constraints of the nearfar problem are loosened, and the system will be immune to jamming. The performance in the absence of synchronism between channels and with imperfect demodulation of the spread code is studied by theoretical analysis and simulation.
Yagi‐uda array antenna composed of twin‐delta loops
Authors: Tou Shigefumi , Tsukiji Takehiko 
Published: July 2007

AbstractWhen two regular triangular loops with peripheral lengths which are approximately equal to the wavelength are placed on a plane and fed in parallel to form an antenna, it acquires high gain and wide bandwidth. The overall properties of this antenna can be modified by changing the geometry of the loops. We propose a Yagi‐Uda antenna consisting of these triangular elements which has high gain and wide bandwidth with a small number of loops. Some numerical results when two or three loops are used are obtained by means of the moment method based on the Hallen integral equations, and the results are compared with experimental results. With a 2‐element array antenna consisting of a radiator and a reflector, the gain variation is small over an octave frequency range (the absolute gain is as high as 9.6 dB) and the impedance is also wideband. A high‐gain, wideband operation will be achieved with a small number of elements when combined with conventional dipole directors.
Parallel queues with common service process and their input controls
Authors: Fukuda Aki'Ra , Sato Shoji , Mukumoto Kaiji 
Published: July 2007

AbstractIn the parallel queue with common service process, there are m independent arrival processes to m waiting spaces. When customers are waiting in all of the waiting areas, the server accepts a customer from each waiting space, and the service is made simultaneously to the m customers. This paper discusses the fundamental properties of such a system, presenting the approximate analysis, qualitative interpretations, and simulation. It has been well known that this kind of system is essentially unstable for any load. This paper presents first the qualitative interpretation for the instability and discusses its relation to the cointossing. Then several heuristic input control schemes are proposed. Their usefulness, control characteristics and the effect of the dalay in the control path are discussed. It is shown as a result that the system can easily be stabilized by a weak input control, and can be stabilized for the case of m =2, even if only one of the queues is controlled. It is indicated also that a too strong control has an adverse effect if there exists a delay in the control path. Several additional observations are made.
Transient probability of complete system failure for an electronic switching system
Authors: Masuda Kohsaku 
Published: July 2007

AbstractThe redundant construction of a switching system, such as n‐tuple, n active plus m standby and n‐tuple plus m standby systems, can be represented by the birth‐death process model, which is a finite‐order Markov process. It is shown that the transient probability for the system failure is given by Pn(t) Pn[1 – exp(– 1/2 {1/TnP t + 1/Tn‐δ)Pn (t – δ)}], where Pn is the steady‐state probability that the redundant structure is in system failure, and P =Un/(Tn + Un); Tn and Pn are the mean times in which the system arrives at the system failure state n from the normal state 0 for the first time, and the time to arrive at the state 0 from the state n, respectively. They are equal to M.T.T.F (Mean Time to Failure) and M.T.T.R. (Mean Time to Repair), respectively; δ is a constant which is determined separately, and is given by =(n – 1) 1/μ where 1/μ is the mean repair time of the unit. It was verified that the approximation is close to the transient solution of the differential equation representing the actual situation. The result is then applied to the analysis of the switching system to derive the unavailability Pn(t) of various redundant structures.
Consideration of characteristics of multipacket transmission in erroneous channel
Authors: Komatsu Masaharu 
Published: July 2007

AbstractIn multipacket transmission, one or more packets is inserted in one frame. Thus, the overhead per packet is smaller than that of single‐packet transmission. However, a larger frame length suggests a higher error probability, a larger packet retransmission rate, and a larger transmission delay. In this paper, considering packet retransmission by error detection, we analyze two basic multipacket transmission schemes, gating‐service‐type and exhaustive‐service‐type, and the ordinary single‐packet transmission scheme. Also, from numerical examples, it is shown that the gating‐service‐type multi‐packet transmission scheme is superior to the other two schemes both in throughput and packet delay characteristics.
Realization of grounded/ungrounded and equal/unequal‐valued switched‐resistors
Authors: Fukai Sumio , Tsukahara Masahisa , Ishikawa Hirobumi 
Published: July 2007

AbstractAs a method for realizing equivalent resistance useful for monolithic integrated circuits, a switched‐resistor circuit has been proposed. In this method, the linear resistance region of the FET is used, and hence the device works as a continuous time system. However, the proposed circuit is only for the case of realizing a single resistor. There does not appear to be any proposals for realization of several resistors. In this paper, from the viewpoint of the number of elements, a circuit configuration is proposed in which grounded/ungrounded and equal/unequal‐valued resistors are realized with a small number of elements. The circuit configuration is based on the single pretune circuit in a pretuned structure used in a time domain multiplex. A switching circuit controlled by a multiphase clock is used. The new pretune circuit here is suited for realization of the case in which the grounded and ungrounded resistors coexist. Two pretune circuits and two switching circuits are presented. Two cases are shown for realization of unequal‐valued resistors. As an application, a third‐order high‐pass filter with three switched resistors is demonstrated.
Multibeam array antenna for data relay satellite
Authors: Teshirogi Tasuku , Chujo Wataru , Akaishi Akira , Hirose Haruzo 
Published: July 2007

AbstractAs the use of space expands, the demand for data relay systems between satellites used for real time data transmission between the ground station and a satellite has increased. This paper proposes a data relay multiple‐access system between satellites which is suited for a relatively small number of users in Japan. The paper also describes the 19‐beam multibeam array antenna developed for this system. Compared to NASA's AGIPA system, the present on‐board multibeam system has a number of advantages: effective use of frequency and power; simplification; and cost effectiveness of the ground station if the number of user satellites is small. Next, a multibeam antenna system suited for this system is studied. It is found that the multibeam array is suited in the case where many beams are formed with a relatively small aperture. The configuration and design method are described. As individual elements, a newly developed broadband microstrip array and a small beam‐forming circuit with a good beam‐forming capability are described. Based on these devices, a 19‐element array antenna with 19 multibeams and one scanning beam is developed. Its technical possibility is proven as a satellite‐borne antenna.
Some encryption networks and an evaluation function for cryptosystems
Authors: Ikeno Nobuichi 
Published: July 2007

AbstractThis paper considers a problem of realizing encryption circuits in the form of the cascade connection of basic circuits and finds a very simple basic circuit which enables an arbitrary encryption. A simple circuit form in the minimum stage circuits is proposed. Next, a quantity is defined which seems to be a criterion for measuring the strength of encryption and not only are several of its properties shown, but also how this quantity appears for a few crypto‐systems including the cryptosystem based on the forementioned circuit form.
Design of sound source with fresnel‐zone pattern and its field analysis
Authors: Hidaka Ryo , Kikuchi Tsuneo , Moriizumi Toyosaka , Shiokawa Showko , Nomura Tooru 
Published: July 2007

AbstractWhen an interdigital transducer (IDT) is loaded with a liquid, an acoustic beam can be excited in the liquid. To focus this acoustic wave in the liquid, the authors have used an IDT that is divided in a Fresnel zone type in the direction of the electrode aperture. From a theoretical calculation of the focused acoustic field generated by the Fresnel zone IDT, it is found that the point of maximum sound pressure is closer to the electrode than the designed focal point. To find the cause of this discrepancy, the acoustic field excited by the Fresnel zone source is analyzed. It is found that a modification in the design model of Fresnel zone IDT's is needed due to the difference between the two‐ and three‐dimensional fields. A new optimum design method is proposed in which the focal point obtained from field analysis and that obtained from the electrode design model coincide.
A telephone network overload control scheme using adaptive control
Authors: Satake Yasuhiro 
Published: July 2007

AbstractThis paper proposes an input regulation overload control scheme of a telephone network using a self‐tuning regulator as one of the adaptive controls. The exchange node is modeled by a simple queue and servers and input traffic is regulated by a switch according to the control signal. In this scheme, dynamic characteristics are estimated using control signals and state variables of the system. The control signal is determined based on these characteristics so that it minimizes the mean square of the difference between the state variable and the control reference which prevents the throughput deterioration. Simulation studies show that the proposed control scheme can maintain the throughput even under extreme overload traffic and large control delay.
Analysis of error propagation and design of filter cutoff frequency in a quantized feedback dc‐restoration system
Authors: Yamaguchi Haruo 
Published: July 2007

AbstractIn the regenerative repeater in digital transmission, the low‐frequency component of the transmitted pulse is cut off by the coupling circuits at the input and the output. However, by applying the quantized feedback dc‐restoration circuit in the repeater the digital regenerative transmission with low dc‐balance transmission code can be achieved. In the quantized feedback system, the component lost in the low‐frequency cutoff characteristics of the transmission system is restored by feeding back the low‐frequency component of the pulse regenerated in the repeater to the decision circuit input. Because of this mechanism, however, an error propagation occurs where an error component is fed back to produce a distortion and to enlarge the error, when a decision error is produced in the repeater. This paper derives the state‐transition diagram which approximates the error propagation. By the analysis of the state‐transition diagram, the relation between the filter cutoff frequency and the error propagation characteristics is determined. Furthermore, it is shown by a simulation experiment that the result of the analysis is a good approximation to the error propagation. Based on these results, a design method is presented for the cutoff frequencies of the forward and the feedback low‐pass filters in the quantized feedback system.
Evaluation of transient intermodulation distortion in operational amplifiers
Authors: Kitamori Susumu 
Published: July 2007

AbstractWhen a transient signal with rapid rising is applied to an operational amplifier, and the input amplitude is increased, the output is influenced by the slew‐rate. If multiple signals are amplified simultaneously by such an amplifier, transient intermodulation distortion arises in the output. In this paper, first, the transient intermodulation distortion rate is measured for the variation of input voltage to a general‐purpose operational amplifier when a rectangular wave or the convolution of a triangular wave and sine wave are used as input signals. Next, as a method for estimating quantitatively the influence of this transient intermodulation distortion over tone quality, we obtain a d' value by applying signal detection theory to experimental results on the audibility. Then, by determining that transient intermodulation, distortion can be discriminated on the sense continuous body when d' =1, and by obtaining the value of the transient intermodulation distortion rate corresponding to the case, we estimate transient intermodulation distortion in an operational amplifier.
Height estimation of a cruising aircraft via a radar for air traffic control
Authors: Nagaoka Sakae 
Published: July 2007

AbstractInformation on the three‐dimensional position of aircraft is necessary for air traffic control. The current height information of aircraft does not always show a geometric altitude since it is based on an onboard barometric altimetry system. Therefore, a method for monitoring the height of aircraft independently of barometric sensors is desirable.This paper describes a method of height estimation for an aircraft flying at a constant speed, level and straight using a radar for air traffic control currently in use or to be used in the near future, and presents the results of consideration on the estimation accuracy of the proposed method. In this method, the data taken by approximately ten times the scans by a fan beam are used for height estimation based on the curve which fits under the assumptions that the data acquisition area is nearly 10 NM the distance from the antenna.Height estimation accuracy by this method is evaluated by a computer simulation. The results show that height estimation accuracy depends strongly on the data acquisition area (that is, the geometrical relation between aircraft and the radar sensor), and the influence of range measurement accuracy is predominant at a cruising altitude of 29,000 ft (= 8.84 km). The height estimation accuracy is estimated to be approximately 100 m (1s̀) under the best conditions assuming that the standard deviation of range measurement errors is 30 m (1s̀) and that of azimuth errors is 0.06 deg (1s̀).
Electromagnetic scattering by a perfectly conducting rectangular cylinder located near the conducting plane
Authors: Ogura Takao , Kozaki Shogo 
Published: July 2007

AbstractThe scattering problem is analyzed in the case where an electromagnetic wave is incident on a perfectly conducting rectangular cylinder located near the conducting plane. Since it is difficult to solve this problem directly as the boundary value problem, the problem is replaced with that of scattering by two conducting rectangular cylinders by means of the method of electrical image. The analysis is based on the point matching method and the amount of computation is reduced by reducing the number of simultaneous equations derived from the boundary conditions into one‐half by using the symmetry of the electromagnetic field. As the numerical examples, the near field and the scattering patterns are presented which have not been reported often. Numerical results are compared for the perfectly conducting circular cylinder located near the conducting plane with those of the rectangular cylinder. To confirm the theory, a model experiment is conducted at microwave frequencies so that reliability of the theory is tested.
A proposal on digital watermark in document image communication and its application to realizing a signature
Authors: Komatsu Naohisa , Tominaga Hideyoshi 
Published: July 2007

AbstractWith the advance of telematic technology, increasing document image information utilized in the state of soft copy is expected. In these situations, copies of obtained document image information are made illegally with ease, and hence the validity authentication of the information itself and its provider becomes more necessary. Since document image information to be authenticated exists in a form which can be read at an unidentified number of receiver terminals, the realization of an authentication scheme where document image and signature are combined is necessary. This is characteristic of document image information including nature pictures and photographs.This paper proposes a new concept of signature, which is called “digital watermark” for document image communication. A digital watermark is the coding scheme in which secret information is embedded into a document image similar to a watermark. Image coding schemes already proposed are available to realize a digital watermark. We present a method of obtaining a digital watermark using a well‐known predictive coding algorithm. Also, we define a criterion for security and show to what extent the digital signature is safe using simulation results, where two or three illegal actions are considered.