Radix-2 트리 ATM 스위치를 위한 멀티캐스팅 알고리즘에 관한 연구

김홍열,임제택 대한전자공학회 1997 電子工學會論文誌, S Vol.s34 No.1

A wide class of networking application services, such as video teleconferencing, VOD, LAN bridging, and distributed data processing require multipoint communications. The essential component inteh network to achieve this is a multicast packet switch which is capable of packet replication and switching. In this paper, we propose an efficient mukticast addressing scheme using the smallest number of routing bits which is deterministic lower bound. The new scheme performs all point-to-multipoint connection in radix-2 tree ATM switch like banyan network. Also, we provide a simple radix-2 switch block diagram for achieving our algorithm. And we investigate several addressing schemes for implementing multicasting in radix-r tree ATM switch and evaluate several performance factors, such as complexity of the additional header bits, requirement of the internal speedup and complexity of the major hardware.

PAM 신호의 비대칭 분포를 형성하기 위한 방법과 이를 이용한 3차 통계 자력 등화기의 성능 비교

정교일,임제택 대한전자공학회 1996 전자공학회논문지-B Vol.b33 No.6

We propose a 3rd order blind equalizer that incorporates a new transform method using either square root operation ($\sqrt{x]$) or reciprocal operation (1/x) in order to transform symmetric distribution of PAM signals at the transmitter, to asymmetric one. At the receiver, either the square operation or the reciprocal operation is needed to recover the asymmetrically transformed signals to the original ones after eualization. The reslts of the computer simulation, using the new method are better than the existing transform method using natural logarithm operation by the maximum of 8 dB in MSE. In addition, as the skewness of the asymmetrically transformed distribution has small values, the performances are improved.

신경회로망을 이용한 선형/비선형 시스템의 식별과 적응 트래킹 제어

조규상,임제택 대한전자공학회 1996 전자공학회논문지-B Vol.b33 No.5

In this paper, a parameter identification method for a discrete-time linear system using multi-layer neural network is proposed. The parameters are identified with the combination of weights and the output of neuraons of a neural network, which can be used for a linear and a nonlinear controller. An adaptive output tracking architecture is designed for the linear controller. And, the nonlinear controller. A sliding mode control law is applied to the stabilizing the nonlinear controller such that output errors can be reduced. The effectiveness of the proposed control scheme is illustrated through simulations.

비대칭 분포의 PAM 신호와 3차 통계에 의한 자력 등화 기법

정교일,임제택 대한전자공학회 1996 전자공학회논문지-A Vol.33 No.7

The probability distributio function (pdf) of transmitted symbols should be asymmectric for recovering the received data in the 3rd order blind equalizer system. In this paper, we hav edesigned the blind equalizer using symmetric-asymmetric (SA) and asymmetric-symmetric (AS) transforms for less computational complexities and robustness in the noisy environments. The method of SA and AS transform was peformed using natural logarithmic operation. This paper proves that the proposed in this paper can be performed as real time operation. This paper proves that the compression factor k has no effet on transmitted symbols. Also 3rd order equalization method proposed in this paper can be performed as real time operation. As a result of computer simulatio, the computational complexity of proposed algorithm is reduced to be an half of 4th order method and MSE is enhanced as 10dB at the case of 4-PAM and 15dB at the case of 8-PAM respectivley. Conclusively, we have found that 3rd order blind equalizer can be implemented when the pdf of transmitter is asymmetric.

신경회로망의 쟈쿄비안을 이용한 feedforward/feedback 병합제어기 설계

조규상,임제택 대한전자공학회 1996 전자공학회논문지-B Vol.b33 No.2

This paper proposes a combined feedforward/feedback controller which uses jacobians of neural network. The jacobians are calculated form the neural network that identifies the nonlinear plant, which are used for designing a jacobian controller and for training a neural network controller. Normally, it takes much time to train the neural network controller. Combining the neural and the jacobian controller, it can be a stable controller from the beginning of training phase of neural network, and it can be implemented as a learning-while-functioning controller. Simulated resutls for the proposed controller show its effectiveness and better performances.

개방 시스템 응용을 위한 개선된 ASN.1 컴파일러 설계 및 구현

김홍열,임제택 대한전자공학회 1996 전자공학회논문지-A Vol.33 No.3

Syntax notation one (ASN.1) defined by ITU-T and ISO, is a formal abstrct specification language which has been widely used in international standards specifiation to inteconnect distributed open systems. It si necessary to have well defined encoder/decoder modules which taranslate ASN.1 datum to BER octets stream to interconnect distributed open systems. In this paper, we designed and implemented a new ASN.1-to-C compiler, called HYASNC (hanyang ASN.1-to-C), which atutomatically translates and ASN.1-to-C compiler, called HYASNC (hanyang ASN.1-to-C), which automatically translates an ASN.1 specification into C-language BER encoders and decoders with simple and neat I/F for the defined ASN.1 data types, and enhanced BER (basic encoding rules)encoding/decoding libraries, called HY(hanyang)BER library, and useful utility functions. And this paper discusses HYASNC compiler, HY BER runtime library's design and implementation principles, and also evaluates the perfomrance of HY BER library and the interoperability with other ASN.1 compilers.

수렴속도 개선을 위한 하이브리드 자력 등화기

정교일,임제택 대한전자공학회 1996 전자공학회논문지-A Vol.33 No.12

In this paper, we propose a hybrid blind equalizer with TEA and SG (stop & Go) algorithm with switching point a 0 dB of MSE value for improvement of convergence performance, where TEA is used initially to open the eye and then SG algorithm as rapid convergence is employed. The switching point is selected at the point of 0 dB MSE level because of settling the coefficients of blind equalier. As a result of computer simulatons for 8-PAM in the non-minimum phase channel, the proposed algorithm has better convergence speed as 3,500 ~ 4,500 iterations and has better MsE about 3 ~ 6 dB than those of original TEA. Also, computational cost of proposed algorithm is reduced as 5 ~ 16% than that of original TEA. and, the proposed algorithm has better convergence than SG algorithm as 8,500 ~ 17,500 iteratins but, the MSE is similar to original SG.

Weight 최소화법을 이용한 외로 설계

김희석,임제택 대한전자공학회 1985 전자공학회지 Vol.22 No.2

MCO 문제의 해석을 하기 위한 weight P-norm방법을 연구하여 새로운 non-inferior해를 구하였다. Weight 최소화방법을 MOSFET NAND 게이트에 적용하여 최적 non-inferior해를 구하였다. 또한 본 논문에서 응용한 최소화방법은 목적함수가 non-convex일때도 적용된다. 본 논문의 최소화 방법의 결과를 Lightner의 결과와 비교하여 효율성을 입증하였다. A new non-inferior solution is obtained by investigating method of weight p- norm to explain the conception of MCO (multiple criterion optimization) problem. And then the optimum non-inferior solution is obtained by the weight minimization method applied to objective function of MOSFET NAND rATEAlso this weight minimization method using weight P- norm methods can be applied to non-convex objective function. The result of this minimization method shows the efficiency in comparison with that of Lightner.

입체각을 이용한 관골구와 대퇴골두의 접촉영역 측정

최교환,임제택,김선일 대한전자공학회 1998 電子工學會論文誌, S Vol.s35 No.2

We developed a method for the solid angle estimation of acetabular coverage of the femoral head in 3D space. The superior half of the femoral head is modeled as part of a sphere. And the tangent lines connecting from a set of points of the acetabular outline to the center of the fitted sphere are obtained. The lines passthrough the unit sphere whose center is the same as that of the femoral head. The interesecting points form a boundary on the unit sphere. With the points on the unit sphere, we calculate the covered area of the femoral headand estimate the solid angle. Solid angle is defined asthe suface area within the boundary on the unit sphere. In this measurements, the solid angle of normal subjects is on an average 4.3(rad) and the corresponding acetabular coverage is 68%. Unlinke the conventional methods, this solid angle estimation shows real 3D acetabular coverage.