• Journal of the Korea Computer Industry Society
• /
• v.3 no.1
• /
• pp.95-104
• /
• 2002

This paper presents some studies on the Internet TCP/IP(Transmission Control Protocol-Internet Protocol) traffic over ATM(Asynchronous Transfer Mode) UBR(Unspecified Bit Rate) and ABR(Available Bit Rate) classes of service. Fuzzy logic prediction has been used to improve the efficiency and fairness of traffic throughput. For TCP/IP over UBR, a novel fuzzy logic based cell dropping scheme is presented. This is referred to as fuzzy logic selective cell drop (FSCD). A key feature of the scheme is its ability to accept or drop a new incoming packet dynamically based on the predicted future buffer condition in the switch. This is achieved by using fuzzy logic prediction for the production of a drop factor. Packet dropping decision is then based on this drop factor and a predefined threshold value. Simulation results show that the proposed scheme significantly improves TCP/IP efficiency and fairness. To study TCP/IP over ABR, we applied the fuzzy logic ABR service buffer management scheme from our previous work to both approximate and exact fair rate computation ER(Explicit cell Rate) switch algorithms. We then compared the performance of the fuzzy logic control with conventional schemes. Simulation results show that on zero TCP packet loss, the fuzzy logic control scheme achieves maximum efficiency and perfect fairness with a smaller buffer size. When mixed with VBR traffic, the fuzzy logic control scheme achieves higher efficiency with lower cell loss.

• Journal for History of Mathematics
• /
• v.20 no.3
• /
• pp.105-126
• /
• 2007

The present paper considers how to teach mathematical concepts. In particular, we aim to a balanced, unified achievement for three elements of concept loaming such as concept understanding, computation and application through one's mathematical intuition. In order to do this, we classify concepts into three patterns, that is, intuitive concepts, logical concepts and formal concepts. Such classification is based on three kinds of philosophy of mathematics : intuitionism, logicism, fomalism. We provide a concrete, practical investigation with important nine concepts in theory of vectors from the viewpoint of three patterns of concepts. As a consequence, we suggest certain solutions for an effective concept learning in teaching theory of vectors.

• Journal of Advanced Navigation Technology
• /
• v.16 no.1
• /
• pp.62-69
• /
• 2012

Multiple-control Toffoli(MCT) gates are macro-level multiple-valued gates needing quantum technology dependent primitive gates, and have been used in Galois Field sum-of-product (GFSOP) based synthesis of quantum logic circuit. Reversible logic is very important in quantum computing for low-power circuit design. This paper presents a reversible GF4 multiplier at first, and GF4 multiplier based quaternary MCT gate realization is also proposed. In the comparisons of MCT gate realization, we show the proposed MCT gate can reduce considerably primitive gates and delays in contrast to the composite one of the smaller MCT gates in proportion to the multiple-control input increase.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.23 no.4
• /
• pp.787-795
• /
• 1998

In this paper, we have improved the speed of gradient operation, which needs to calculate Optical Flow for estimating a moving object, and proposed a method which estimate the contour of a moving object by the logical operationg of Optical Flow and edge in noisy images. The proposed method, which recognize to a moving ogject and traking a moving object, using logical operation of Optical Flow and edge in low-level has a advantage that is simpler than the known method for moving objects estimation. In addition, we have simulated several images using method I and method II on improved Gradient operation speed. When we have compared the average value of total operation time, method I is improved with 12% of operation speed compared with the known method, method II is improved with 38% operation speed.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2005.11a
• /
• pp.427-430
• /
• 2005

지능형 로봇이 성장동력 산업으로 선정되면서 국내에서도 로봇 산업이 급속도로 성장하고 있다. 지능형 로봇과 관련해서는 특히 자율 이동 로봇, 그리고 그것의 경로계획과 주행에 관한 연구가 널리 진행되고 있다. 자율 이동 로봇은 주어진 환경에서 효율적인 주행을 하기 위하여 환경 지도를 구성하고, 이를 기반으로 목표 지점에 대한 효율적인 광역 주행 경로를 계산하게 되고, 계산된 광역 경로를 주행하여 목표 지점에 이르게 된다. 본 논문에서는 퍼지 환경 지도를 제안하고, 퍼지 환경 지도로부터 최단시간 광역 경로 계산 알고리즘을 소개하며, 주행 제어를 위한 퍼지 논리 제어기를 제안한다.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2012.07a
• /
• pp.163-166
• /
• 2012

본 논문에서는 퍼즐을 활용하여 초등정보영재교육 방안을 제안하고자 한다. 현재의 정보영재 교육과정을 살펴보면 프로그래밍학습과 알고리즘 학습에 치중하고 있다. 이것은 직접 체험하고 조작하며 학습하는 초등학생의 특성상 효과적인 방법이 아니다. 따라서 흥미와 재미의 요소를 포함하고 정보교과의 부담을 줄여주며 논리적인 사고력을 향상시켜줄 수 있는 퍼즐을 활용한 초등정보영재교육을 제안한다. 또한 최근 컴퓨터 과학에서 강조하고 있는 계산적 사고(Computational Thinking)와 퍼즐활용교육과의 관계를 살펴보고 퍼즐활용 교육을 통해 계산적 사고를 기를 수 있음을 제시한다. 추후에 초, 중, 고 정보영재교육을 연계를 위한 퍼즐 교육에 많은 연구가 필요하다.

• Journal of the Korean Data and Information Science Society
• /
• v.6 no.2
• /
• pp.17-27
• /
• 1995

We propose a framework for representing and processing uncertain knowledge on the basis of constraint satisfaction. A system of equations and/or inequalities can be considered as a set of constraints that should be solved, and each constraint in the set is transformed into a corresponding logical formula which can be solved through a constraint solving program. Most of rule-based systems, for instance, use a simple probabilistic theory in order to maintain uncertain knowledge, therefore uncertain knowledge can be represented and processed in the constraint satisfaction program quite efficiently.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.7 no.2
• /
• pp.3-15
• /
• 1997

In order to apply fuzzy logic, two major tasks need to be performed: the derivation of fuzzy rules and the determination of membership functions. These tasks are often difficult and time-consuming. This paper presents an algorithmic method for generating membership functions and fuzzy rules applicable to decision-making problems; the method includes an entropy minimization for clustering analog samples. Membership functions are derived by partitioning the variables into desired number of fuzzy terms, and fuzzy rules are obtained using minimum entropy clustering. In the mle derivation process, rule weights are also calculated. Inference and defuzzification for classification problems are also discussed.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.18 no.5
• /
• pp.30-34
• /
• 1981

This paper deals with the testability evaluation method for the digital systems. This method uses two factors: the complexity and the accessibility. The complexity depends on the ratio in combinational and sequential circuits, number of input/output terminals, and the circuit count by using the gate input level method. The accessibility is how easily to handle the data from I/O terminals. The system testability has a normalized value. Thus, analyzing the testability evaluation, and redesigning the circuit to improve testability, the systems increase interests for the maintenance and have high reliability. Finally, in comparison with Stephenson and Grason's technique, this technique gives sufficiently accurate results for much less computation effort.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2011.01a
• /
• pp.89-92
• /
• 2011

본 논문에서는 컬러 영상에 대해 삼각형 타입의 소속 함수를 적용하여 스트레칭의 상한과 하한을 동적으로 설정하고 영상을 스트레칭 하는 방법을 제안한다. 제안된 퍼지 스트레칭 방법은 평균 밝기 값을 기준으로 가장 어두운 픽셀 값과 가장 밝은 픽셀 값의 거리를 계산하여 밝기의 조정율을 결정한 후, 최소 밝기 값 및 최대 밝기 값을 구하고 삼각형 타입 소속 함수의 구간에 적용한다. 영상의 픽셀 값들을 소속 함수에 적용하여 소속도를 구하고 cut를 적용하여 가장 낮은 픽셀 값을 스트레칭 하한으로 가장 높은 픽셀 값을 스트레칭 상한으로 설정하여 컬러 영상을 스트레칭 한다. 다양한 영상에 적용한 결과, 기존의 스트레칭 방법보다 제안된 퍼지 스트레칭 방법이 효율적인 것을 확인하였다.