摘要:

AbstractSince the model for the voice/data multitraffic processing system was proposed, various analyses have been made for the system. However, the traditional analysis derived only the average and the variance of the data call queues.A general and practical method of analysis has not been presented for the waiting time distribution of the data calls, which is important as the service criterion. This paper proposes an approximate method of traffic analysis for the integrated voice/data system, which is applicable to data calls with the holding time following the general probability distribution.The method is to represent the holding time distribution of the data call following the general probability distribution as a sum of several pseudo‐data calls following exponential distributions. By this method, not only the average waiting time but also the distribution of the waiting time can be calculated relatively easily.As in the design for a voice communication network, the integrated network can be designed so that the given service criterion is satisfied by 99 percent of the data calls in the data system. As an example, the case of facsimile as the data source is examined. The result by the proposed method agreed well with the result of simulation, indicating that a practically sufficient accuracy is realize

ISSN:8756-6621    

DOI:10.1002/ecja.4410731101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThis paper presents an excellent two‐moment approximation via an N‐environment diffusion model of a queueing system with Markov modulated Poisson process (MMPP) arrivals and general service time distribution. By choosing residual workload as a performance criterion, an approximation error of less than 3 percent can be achieved.We give a closed form solution for all moments of the waiting time distribution with two‐state MMPP arrivals. We also propose an algorithm for the approximate solution of single server queueing systems withn‐state MMPP arrivals. The proposed sufficiency condition for the existence of a stationary solution has not been proved for then‐state case

ISSN:8756-6621    

DOI:10.1002/ecja.4410731102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThis paper considers the speed of communication where NTSC and HDTV video signal is encoded into digital forms, and proposes a high‐speed broadband circuit switching system which realizes the integrated services covering communication services and distribution services. The former include the end‐to‐end communication such as TV conference and the video retrieval such as image inquiry system, and the latter includes the CATV.The proposed method has the following features: (1) The communication services and the distribution services are distinguished by using layer 3 of I interface protocol. The video channel selected by the subscriber is transferred between the subscriber and the service processing node of the video distribution system, using the high‐level layer signal; (2) considering the uncertain demand, a building block structure is adopted, where the unit is the small‐scale independent switching and distribution module with several tens to several hundreds of subscribers; (3) the load‐function distributed control scheme is adopted.In the communication services, the functions are divided into the modules of subscriber accommodation, intermodule connection, inter‐office signal processing and system management. In the distribution services, the divided modules such as the selection of video channel and the interface processing to the video operation center are executed in the almost complete processing within the module, which helps to reduce the communication traffic be

ISSN:8756-6621    

DOI:10.1002/ecja.4410731103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThis paper discusses the technical feasibility of the multimedia metropolitan area network based on the tree‐shaped broadband network, employing two‐way CATV technology. In the proposed network, all information can flow on any transmission line through the headend. This leads to the following features, which cannot be realized in the star network as in the telephone network:1Flexible services are provided.2An efficient information communication service can easily be realized.3It is easy to provide the highspeed broadband service at a low cost.4The security of the network can be improved.The following systems were developed by the authors as examples of the information communication services utilizing those features: TDMA circuit switching service using “time‐slotted bus with control window,” CSMA/CD packet switching service using “beat signal level detection,” and TDMA video switching service, where several video signals are multiplexed as analog signals. Those services can be provided to more than 10,000 subscribers in a service area of diameter 20 km or more. The system is expected to provide the basis for the information communication in local communities, together with the widespread use of ur

ISSN:8756-6621    

DOI:10.1002/ecja.4410731104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractRecently, to realize broadband ISDN, ATM has been studied vigorously. As the switching network for ATM, the delta network and other switching networks have been investigated by a number of researchers. The delta network performs the self‐routing based on the multistage connection of 2 × 2 sized matrix switches. However, this network has a problem in that the throughput is decreased drastically when the traffic imposed on the switching network is nonuniform.To avoid such a situation, a method is proposed to make the whole network a Benes network by placing a distribution network preceding the delta network to balance out the traffic. The addition of the distribution network, however, has only been investigated for the case where all matrix switches are of the same size.With this as the background, this paper discusses the switching network with several sizes of matrix switches. The method of placing the distribution network is discussed together with the characteristics, and application examples are present

ISSN:8756-6621    

DOI:10.1002/ecja.4410731105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractA high‐speed multiplex transmission system has recently been proposed based on ATM, where the information is divided into fixed‐length blocks called cells, and transmitted on asynchronous multiplexing basis. As the switch to be used in the transit node in such a transmission system, various kinds of switching networks have been proposed, composed of two‐input × two‐output switch elements with internal buffers. Among those, the multistage buffered Banyan structure, which is a cascade connection of two Banyan networks as the distribution and routing networks, is of a distributed structure, being suited to LSI implementation. The network is a promising candidate since it realizes the self‐routing and is stable against a variety of traffic. However, this switching network has a problem in that the delay is increased with the scale of the network, and the in‐service expansion of the switching network is not easy.This paper proposes a new network topology of the Banyan network with bypass links, together with the self‐routing method, and describes its performance. The network is composed of the distribution and routing networks with bypass links between individual unit switches. By transferring cells from the distribution network to the routing network through the bypass links at appropriate stages, the delay is reduced. The in‐service expansion of the sys

ISSN:8756-6621    

DOI:10.1002/ecja.4410731106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe conventinal shared buffer‐type switch in ATM multiplexes the cells, and a large number of cells is stored in a memory. This produces a problem in that the speed within the switch must be increased, which is limited by the speed of the circuit.This paper proposes a shared buffer‐type switch in which a number of memories are provided, each storing a cell, and the switching is executed without the cell multiplexing. Several features are realized as follows.The required number of buffers is less than in the output buffer type. The priority control and the broadcasting can be realized. There is a flexibility in that the number of input and output lines are arbitrary. If the proposed switch with a high speed is used in the multistage switching network, a switch with an excellent performance such as low‐loss rate and high throughput can be obt

ISSN:8756-6621    

DOI:10.1002/ecja.4410731107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThis 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 a

ISSN:8756-6621    

DOI:10.1002/ecja.4410731108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractSmall‐signal dynamic analysis of a class E resonant dc‐dc converter is presented where voltage regulation is done by an auxiliary switch without changing the switching frequency. This converter is suitable for high‐frequency operation because both the main and the auxiliary switches can be turned ON/OFF at zero voltage level and the switching loss is very low.Small‐signal dynamic characteristics are determined by an averaging model obtained by the use of Fourier series expansion where the terms higher than second order have been neglected. Experiments are performed on a 1‐MHz switching converter and the applicability of this analysis is

ISSN:8756-6621    

DOI:10.1002/ecja.4410731109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractFrequency selective surfaces (FSS) have been developed for applications to the 45‐m telescope of the Nobeyama Radio Observatory (NRO), the National Astronomical Observatory (NAO), Japan, for simultaneous observations of radio astronomical sources at the 40‐ and 80‐GHz bands.The Jerusalem‐cross array configuration has been used for the conducting array. The designed characteristics satisfy requirements for radio astronomy: small insertion losses and little distortion of polarization. The measured characteristics were in good agreement with the calculated ones. The fabricated FSS has low insertion loss of 0.1 and 0.6 dB at the 40‐ and 80‐GHz bands, respectively.It was found that the distortion of circular polarization is not significant for polarized radio astronomical sources of polarization degree of more than 5 percent. The characteristics of the developed FSS satisfy solar radio astronomical r

ISSN:8756-6621    

DOI:10.1002/ecja.4410731110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY