This paper proposes an efficient algorithm that constructs 3 dimensional solid object from orthographic views. The 3D object construction algorithm inputs vertices and edges information of 3 orthogonal views, generates 2 dimensional surfaces of input views, 3 dimensional possible vertices, possible edges and possible surfaces, compares 2 dimensional projections of 3 dimensional possible surface with two dimensional surfaces from orthogonal views and then determines the solution. This algorithm has been proved to be efficient in reducing the time taken and is useful for CAD system, 3 dimensional scene analysis system and object modellings for 3D graphics. The algorithm has been implemented in C language on the IBM PC/AT.

This paper proposes a new feature extraction method which is effectively used in character recognition, and validate the effectiveness through various computational methods for similiarity degree. To get feature vectors used in this method, Hough transform is applied to character image, which is used for edge extraction in image processing. By that transformation technique, strokes could be extracted and feature vectors constructed suitably. The characteristic of this method is solving the difficulties in stroke extraction through transform space analysis, which is induced by noise and blurring, and representing high recognition rate 99.3% within 10 candidates in relative low dimension.

In this paper, we present a motion compensated video compression method based on both block and object motions. A simplified objectoriented motion parameter is estimated from the block based motion vectors. A decision rule for the global or local MCP modes is established. Simulation results show that the proposed method has lower bit-rates than the BMA based method at the same reconstruction errors.

A capability of performing the optical logic and arithmetic operations is followed by an effective encoding technique. In this paper, we proposed the color light encoding technique. By using this encoding technique, the space bandwidth product(SBP) is minimized in the output plane. In addition, we proposed the pre-operation pro-carry processing method that performs faster than the same time operation and carry processing method in optical computing. We proposed that the color liquid crystal device(CLCD) is used as the encoded color light input source.

Constant false alarm rate(CFAR) processors are useful for detecting radar targets in background for which all parameters in the statistical distribution are not known and may be nonstationary. The well known "cell averging" (CA) CFAR processor is known to yield best performance in homogeneous case, but exhibits severe performance in the presence of an interfering target in the reference window or/and in the region of clutter edges. The "order statistics"(OS) CFAR processor is known to have a good performance above two nonhomogeneous cases. The modified OS-CFAR processor, known as "trimmed mean"(TM) CFAR processor performs somewhat better than the OS-CFAR processor by judiciously trimming the ordered samples. This paper proposes and analyzes the performance of a new CFAR processor called the "maximum trimmed mean"(MX-TM) CFAR processor combining the "greatest of"(GO) CFAR and TM-CFAR processors. The MAX operation is included to control false alarms at clutter edges. Our analyses show that the proposed CFAR processor has similar performance TM- and OS-CFAR processors in homogeneous case and in the precence of interfering targets, but can control the false rate in clutter edges. Simulation results are presented to demonstrate the qualitative effects of various CFAR processors in nonhomogeneous clutter environments.

FIR형은 하드웨어 규모가 커져서 구성이 어렵다는 단점을 가지고 있으나, IIR형은 적은 차수로써 큰 차수의 FIR필터를 대신할 수 있다. IIR형은 적은 계산량과 간단한 하드웨어 구성이라는 장점을 갖고 있으나 수렴성에 있어서는 어려움이 있다. 본 연구에서는 적은 차수로 양호한 수렴특성을 갖는 IIR 필터를 구성하기 위하여 연속시간영역의 직교필터를 이산시간영역으로 변환하고 직교성을 유지하도록 정규화한 정규직교함수계에 의해서 설정된 전달함수를 적응 디지틀필터에 적용하였다. 이 방법을 확인하기 위하여 FIR형에 비교해서 적은 차수로 컴퓨터 시뮬레이션을 수행한 결과 양호한 수렴특성을 확인하였다.

In this paper, we use LFSR(Linear Feedback Shift Register) as a kind of pseudo-random one-time pad. Key generator is constructed using r separate LFSR's with IP(Irreducible Polynominal) which are relatively prime. Key generated in this method has high linear complexity. And also, file cryptosystem for file encryption and decryption is constructed.

Spectrum Analyzer is a useful measure instrument to display the distributed power of electrical signal as a function of frequency. It adopts the superheterodyne receiver, which mixes RF with L0 to output IF. So in this paper, two GHz-order microstrip low-pass filters, 2-section wilkinson power divider, and singly balanced diode mixer have been designed and implemented necessary to make the frequency converter applied to RF spectrum analyzer.

When the noise has both additive and signal-dependent components, locally optimum detector test statistics are obtained for detection of weak composite signals using the generalized Neyman-Pearson lemma. In order to consider the non-additive noise as well as purely-additive noise, a generalized observation model is used in this paper. The locally optimum detector test statistics are derived for several different cases according to the relative strengths of the known signal component, the random signal component, and the signal-dependent noise component. Schematic diagrams of the locally optimum detector structures are also included.

This paper proposes an efficient adaptive echo canceller using pilot filter approach to achieve improved convergence speed. The pilot filter is an adaptive filter with only a few filter coefficients to filter the received signal for the purpose of whitening the signal. Thus the convergence speed of the main LMS-TDL filter combined with the pilot filter is improved. In the proposed echo canceller, an adaptive lattice predictor as the pilot filter is used and its inverse filter is used to equalize the distorted near end talker signal. Simulation results for colored signal show that the convergence speed of the proposed echo cancellation algorithm is faster than that of the conventional LMS-TDL echo cancellation algorithm.

In this paper we derived the asymptotic distribution of the MUSIC null-spectrum, from which an exact expression of the asymptotic variance of the MUSIC null-spectrum can be obtained. From this result in addition an explicit expression of the normalized standard deviation (NSD) has been derived and it is shown that the NSD is affected by the number of sensors and the number of signals.

In this paper, a new adaptive IIR notch filter employing all pass filter is proposed. Proposed all pass filter is composed of all pole and all zero sections, each of which utilizes modulation lattice filter [11]. And, adaption algorithm for proposed notch filter is also derived. In addition, the error surface for proposed IIR adaptive notch filter is analyzed. Computer simulation results reveal that the proposed adaptation algorithm works well for low SNR(signal to noise ratio) single and multiple sinusoids. And it is shown that for estimation time varying frequency, the parameter which is related to notch bandwidth is important than any other parameters.

A generalization of null-spectrum for use in the estimation of directions of arrival of signal sources is considered in this paper. The upper and lower bounds of the generalized null-spectrum, the maximum and minimum null-spectra, are also derived. We observed that the maximum null-spectrum has higher resolution capability than other null-spectra including the two well-known null-spectra, the multiple signal classification null-spectrum and the Min-Norm null-spectrum.

한국통신 연구개발단에서 개발한 국제망관리시스템(INMS)에서 필요로하는 망관리 데이터는 각 국제교환기로부터 발생즉시 온라인으로 수집되어 분석 처리되어야한다. 이들 망관리 데이터는 양이 많을뿐아니라 여러곳에 분산되어져 있는 교환기로부터 실시간으로 신뢰성있는 데이터를 온라인으로 수집하여야한다. 본 논문에서는 INMS의 온라인 수집시스템을 소개하고, 비동기식 데이터 통신에서의 전송에러검출 기법을 적용한 온라인 프로토콜에 의한 온라인 데이타 수집기법을 소개하였다.

The TDX-10 Time Switch architecture has modularity, high reliability and considerable large switch fabric having separated and both-way 1K time slot interchange switching circuit elements. In this paper, we present key functions, architecture, features and traffic characteristic of TDX-10 Time Switch. And we also describe some basic implementation technologies such as Frame Base Read-Write Separation Method, Multi-Write Method and Read-Write Separation Technique with Dual-port Memory.

In this paper, we analyze the performance of ATM switch with output buffer which has a space priority control mechanism. As we assumed that the input traffic consists of loss tolerable voice and loss sensitive data, we modeled it with MMPP(Markov Modulated Poisson Process). We confirmed that the loss probability of loss sensitive traffic decreases when we use the space priority control mechanism.

In this paper, an algorithm is proposed to analyze the approximating reliability of the capacity considered communication networks. In the case ofthe former methods to evaluate the source-to-termianl node reliability, it is very difficult to contract and delete the jointed terms in the simple path group. Therefore, the reliability bounds are used and compared to the exact reliability by TURBO PROLOG, the natural lanquage of artficial intelligence. In the reliability bounds, the upper bound used the valid cutset that isthe group of simple path and the lower bound used the minimal cutset by complement operation and the esact reiability is compared to this reliability bounds.

As subsriber's requirements for high quality of telecom service are increased, a telecommunication network becomes complex and huge, and its management becomes an essential and an important factor in the evolution of telecommunication networks. In this paper, we focus on the network performance management and discuss the strategy of near real-time performance evaluation and control in Korea Telecome (KT) networks.

In this paper, we investigate key issues and the CCITT activities related to the quality of service in the B-ISDN based on the ATM. We first clarify the relationships between the QOS(Quality of Service). NP(Network Performance), and GOS(Grade of Service). Using the GOS, network design and tuning method is suggested. Also, we examine the performance impairments and key NP parameters in ATM networks.

본 논문에서는 한국전기통신공사에서 도입 추진하고 있는 No.7 공통선 신호방식의 망관리를 위하여 사용될 OMAP의 구성과 기능에 대하여 소개하였다. 국내에서는 아직 공통선 신호방식이 상용화 되지않았으며, 그 관련 기준들도 확정되지 않았으며, 더구나 운용유지보수관리를 위한 OMAP에 대해서는 프로토콜 범위조차 확고히 정립되지 않은 상태이다. 따라서 본 고에서는 THN과 OMAP의 관계를 살펴봄으로써 THN을 구성하기 위하여 필요한 국내의 OMAP 구성방안을 제시하여, OMAP의 프로토콜 정립과 OMAP을 이용한 관련 시스팀들의 구현에 방향을 제시하고자 한다.

본 논문에서는 한국통신 연구개발단에서 개발중인 국간중계회선의 종합관리 시스팀의 기능, 시스팀 구성, 시스팀간 통신에 대한 개략적인 소개를 하였다. 국간중계회선 종합관리시스팀은 현재 한국통신에서 대부분을 수작업에 의존하고있는 국간중계관련 업무를 종합전산화하는 시스팀으로 1991년부터 1996년까지 6년 개발과제로 1994년 1차 시범운용을 통해 시스팀 기능을 시험, 보완하므로써 1996년 이후부터 계획된 실제 운용을 대비하여 시스팀 사용자의 요구 및 실제 운용환경에 부합하는 시스팀을 개발할 예정이다.

현재까지 가입자 트래픽 예측방법은 계량학적 방법중 추세분석 방법을 이용하고 있는데, 이 방법은 급변하는 시장상황이나 지역여건을 고려하지 못하고 하나의 통계적 기술에 의한 획일화된 예측방법으로서 트래픽예측치가 실제 운용트래픽값과는 다소 차이가 있어왔다. 이러한 원인을 제거할 수 있는 하나의 방법으로서 Box-Jenkins 시계열 분석에 의한 트래픽 예측방법을 제안하고자 한다. 이 방법에 대한 이론을 살펴보고, 시뮬레이션을 통하여 얻은 결과를 각각 분석하여 문제점을 파악하고 실측치와 비교분석함으로서 본 논문에서 제안한 방법이 기존방법보다 타당함을 입증하려 하였다.

ATM, the core technology of BISDN, provides a high degree of flexibility with regard to varying bandwidth requirements for different services. In ATM networks, since users may exceed the traffic volume negotiated at the call setup, traffic from users may need to be monitored and enforced to comply with traffic parameters. The leakybucket mechanism is one of the typical traffic enforcement methods based on the use of transmission tokens for each cell. In this mechanism the major system parameters are size of input buffer, size of token pool, and token generation ratio. In order to represent ATM cell arrivals we assume a Poisson process. In this paper, a state transition analysis technique is used to study the cell loss rates for various values of system parameters.

In this paper, we survey traffic control issues for the B-ISDN based on the ATM. We first investigate traffic descriptors to represent the characteristics of various ATM traffics in a standardized form. Also, we examine key issues related to the connection admission control, usage parameter control, network parameter control, priority control, and congestion control.

현재의 국제전화망의 상태 및 성능을 파악하기 위해서 교환기의 과금정보를 이용하여 국제망관리자료를 산출하는 방법 및 그 결과를 논하였다. 교환기에서 측정되는 망관리자료를 수집하는데는 시간이 많이 걸리며, 또 다양한 자료를 얻을 수 없기 때문에 망의 상태를 파악하기가 어렵다. 과금정보로부터 망관리자료를 추출한 결과, 통화량이 많아 중요하게 여겨지는 루트 및 착신지의 소통상황을 실시간으로 파악할 수가 있었으며, 문제가 되는 구간의 복구를 빨리 할 수 있는 상세한 자료를 얻을 수 있었다.

통신망의 가용율을 최대로 유지시켜 가입자에게 만족스러운 서비스를 제공하기 위해서는 통신망을 실시간으로 감시하여 망에서 발생하는 장애 및 과부하 트래픽을 망차원에서 관리해 주어야한다. 그러나 현재 운용중인 운용시스팀의 대부분이 특정기종의 통신설비 및 서비스제공에 관련된 시스팀들로서 망차원에서 통신망을 효율적으로 관리하기에는 미흡한 점이 많이 있다. 본 논문에서는 통신망을 최적의 효율로 운용하기 위한 망관리의 개념에 대해 설명하고 망차원에서 통신망을 관리하기 위해 필요한 지역망관리 시스팀의 일환으로 개발한 지역망 감시 시스팀(RNNS:Regional Network Monitoring System)의 구조 및 설계방법과 아울러 본 시스팀에서 구현한 망감시 기능에 대해 논한다.

This paper addresses the traffic source modeling issues in ATM networks and reviews some related results. Especially these issues are based on the related papers presented in the 13th International teletraffic congress(ITC).

분산 시스팀 환경하에서 여러 다양한 구성요소사이의 상호작용과 통신을 관장하는 규칙들인 프로토콜을 설계하는데 있어서 컴퓨터 과학 및 공학 영역의 형식방법과 소프트웨어 공학기법이 적용되고 있다. 그 결과로서 새로운 영역인 프로토콜 공학(Protocol Engineering)의 중요성이 점차 대두되고 있다. 본 연구에서는 프로토콜 공학 사이클(프로토콜과 서비스 명세, 프로토콜 검정과 검증, 프로토콜 종합, 프로토콜 변환, 성능 평가, 자동 구현, 그리고 적합성 시험) 중에서 적합성시섬 즉, 적합성 시험언어인 TTCN(Tree and Tabular Combined Notation) 특성, 시험시나리오, 그리고 추상적 시험 시나리오를 수행하는 시험언어 번역기(TTCN2C)에 관해서 논하였다.

Recent telecommunication technology trends have made possible the concept of Intelligent Network, which is expected to lead to additional revenues for both telecommunication administers as well as business service customers. In this paper international Korea Telecommunication Network configuration with special services are described and introducing the Intelligent Network Services into the international Korea Telecommunication Network in a phased manner is studied considering of interworking between international and domestic Intelligent Network services.

The conventional modeling equations for planar MOSFET can not be directly used for zero or minus junction depth concave MOSFET. In this paper, we suggest a new model which can simulate the electrical characteristics of concave MOSFET. The threshold voltage modeling was achieved using the charge sharing method considering the relative difference of source and drain depletion widths. To analyze the ID-VDS characteristics, the conventional expressions for planar MOSFET were employed with the electrical channel length as an effective channel length and the channel length modulation factor as ${\alpha}$ΔL. By comparing the proposed model with experimental results, we could get reasonably similar curves and we proposed a concave MOSFET conditiion which shows no short channel effect of threshold voltage(V${\gamma}$).

We briefly compared GaAs MESFET model and s셔요 on the method of parameter extraction for PSPICE simulation. The parameter determined from above method were substituded into a commercial version of PSPICE which supports the hyperbolic tangentent model. The result of simulation is reasonably good at the lower VGS and is significantly fitted overall by optimization.

This paper is equivalent model transform which reduces the restriction of digitalization in the discrete linear system. This algorithm is the method that weight is given to contribillity and obserbility gramian, the regular matrix T of coordinate transform is obtained and then the state space coefficents of weighted model can be obtained. This study shows the frequency reponse of low quantization error according to the order of weighting function. The result shows that frequency response of the proposed algorithm is better than that of the balanced realization in the system of smaller bit.

Uninterruptible Power Supply(UPS) Systems are widely used in a varietyof fields as highly reliable power sources. This paper describes the operation and performance of an UPS using sinusoidal Pulse Width Modulation (PWM)techniques. A newly developed UPS adopted switching element -power TR, power MOSFET, IGBT- is introduced. Experimental results showed that sinusoidal PWM techniques have good features for UPS systems.