• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 1998.10a
• /
• pp.384-389
• /
• 1998

본 논문은 특정 응용에 적합한 퍼지 제어기의 최적 설계 파라메터(퍼지 규칙과 소속 함수)를 찾는데 역전파 학습 과정과 유전 알고리즘을 결합한 Lamarckian 상호적응 기법을 이용한 뉴로-퍼지 제어기의 새로운 설계 방법을 제안한다. 설계 파라메타들은 진화에 의한 전역적 탐색을 통해 높은 포함값과 유용한 퍼지 규칙들을 갖는 규칙 베이스와 작은 근사화 오차와 좋은 제어 성능을 갖는 소속 함수들을 얻도록 제어기간 파라메타 조절을 수행하며, 학습에 의한 국부적 탐색을 통해 각 퍼지 제어기가 원하는 제어 결과를 나타내도록 제어기내 파라메타 조절을 수행한다. 제안한 상호적응 설계 방법은 유전 알고리즘의 모든 세대에서 역전파 학습이 이루어지므로 보다 좋은 근사화 능력을 나타나고, 사용한 무게 중심 비퍼지화기가 정확한 비퍼지화값을 계산하므로 보다 좋은 제어 성능을 가지며, 퍼지 규칙 베이스와 소속 함수들의 최적화 탐색 과정이 입출력 공간의 같은 퍼지 분할 상에서 통합된 적응 함수에 의하여 동시에 수행되므로 탐색을 위한 작업 공간이 아주 작아지는 장점이 있다. 시뮬레이션 결과는 Lamarckian 상호 적응에 의해 얻어진 FLC가 퍼지 규\ulcorner 수, 근사화 능력, 제어 성능등 모든면에서 다른 방법에 의해 얻어진 FLC보다 가장 우수함을 보여준다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.2
• /
• pp.269-272
• /
• 2005

For the efficient image encryption, we proposed the encryption algorithm using the chaotic function and elementary matrix operation defined on the bit plane decomposition. Though the chaotic encryption algorithm is faster than block encryption, it uses a real number computation. In this sense, we use the row and column operations on the bit-plane decomposed images combined with logistic function for the recursive rounding number, too.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.17 no.7
• /
• pp.970-976
• /
• 2007

In this study, Polynomial Network Pattern Classifier(PNC) based on Fuzzy Inference Mechanism is designed and its parameters such as learning rate, momentum coefficient and fuzzification coefficient are optimized by means of Particle Swarm Optimization. The proposed PNC employes a partition function created by Fuzzy C-means(FCM) clustering as an activation function in hidden layer and polynomials weights between hidden layer and output layer. Using polynomials weights can help to improve the characteristic of the linear classification of basic neural networks classifier. In the viewpoint of linguistic analysis, the proposed classifier is expressed as a collection of "If-then" fuzzy rules. Namely, architecture of networks is constructed by three functional modules that are condition part, conclusion part and inference part. The condition part relates to the partition function of input space using FCM clustering. In the conclusion part, a polynomial function caries out the presentation of a partitioned local space. Lastly, the output of networks is gotten by fuzzy inference in the inference part. The proposed PNC generates a nonlinear discernment function in the output space and has the better performance of pattern classification as a classifier, because of the characteristic of polynomial based fuzzy inference of PNC.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.14 no.5
• /
• pp.458-465
• /
• 2003

In this paper, we analyze the transient electromagnetic response from three-dimensional(3-D) dielectric bodies using a time-domain electric field integral equation formulation. The solution method in this paper is based on the Galerkin＇s method that involves separate spatial and temporal testing procedures. Triangular patch basis functions are used for spatial expansion and testing functions for arbitrarily shaped 3-D dielectric structures. The time-domain unknown coefficients of the equivalent electric and magnetic currents are approximated as an orthonormal basis function set that is derived from the Laguerre functions. These basis functions are also used as the temporal testing. Numerical results involving equivalent currents and far fields computed by the proposed method are presented.

• Journal of KIISE:Software and Applications
• /
• v.28 no.2
• /
• pp.168-178
• /
• 2001

진화 알고리즘은 자원 관리, 스케줄링, 패턴 인식 등의 다양한 문제들에 적용되는, 일반적이고 효율적인 최적화 방법이다. 그러나 이러한 진화 알고리즘의 문제점은 탐색해야할 변수가 증가할수록 그에 따른 차원의 증가로 인하여 기하급수적으로 늘어나는 탐색공간에 약하다는 것이다. 이러한 문제점을 해결하기 위해 Potter와 DeJong은 개개의 종족을 독립적으로 진화시킴으로써 탐색공간을 대폭 줄인, 협력 공진화 알고리즘을 제안하였다. 그러나 이것 또한 변수 의존성이 강한 문제들에 대해서는 비효율적인 탐색을 하는 문제점이 있다. 본 논문에서는 종족의 분할과 병합을 이용한 효율적인 공진화 알고리즘을 제안한다. 이 알고리즘은 최적화하려는 변수들이 서로 의존성이 없는 경우에는 종족의 분할을 통하여 탐색공간의 축소의 잇점을 얻고, 최적화하려는 변수들이 서로 의존성이 있는 경우에는 종족의 병합을 통하여 전역탐색을 하도록 한다. 제안하는 알고리즘을 몇 가지 벤치마크 함수 최적화 문제와, 상품 재고 제어문제로 실험하여 현존하는 어떤 공진화 알고리즘 보다도 효율적인 것을 보여준다.

• Korean Journal of Cognitive Science
• /
• v.4 no.1
• /
• pp.123-152
• /
• 1993

This paper discusses how to automatically extract fuzzy rules from given data.The fuzzy space which contain given data are fitst subdivided into a set of hypercubes.each of which contains the homogeneous data belonging to the same class, and then a fuzzy rule is defined based on the constructed hypercube.In order to dynamically agjust the size of a hypercube. the fuzzy space is to be splitted based on a center vector and then the splitted subspaces are to be merged throungh the adjacency relation.The membership functions.which are to be embedded in a fuzzy rule.are to be formed through analyzing the cummulative histogram of given data along each axis of the constructed hypercube.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.35C no.9
• /
• pp.21-28
• /
• 1998

In this paper, we propose an efficient linear ordering algorithm, called LIME, for netlist partitioning. LIME incrementally merges two segments which are selected based on the proposed cost function until only one segment remains. The final resultant segment then corresponds to the linear ordering. LIME also runs extremely fast, because it exploits sparsity of netlist. Compared to the earlier work, the proposed algorithm is eight times faster in producing linear ordering and yields an average of 17% improvement for the multi-way scaled cost partitioning.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.42 no.3 s.303
• /
• pp.7-14
• /
• 2005

In this paper we proposed the block-based color image segmentation method using the cylindrical metric to solve the problems such as long processing time and over segmentation due to noise and texture properties in the conventional methods. In the proposed method we define the new similarity function and the merge condition between regions to merge initial regions with the same size considering the color and texture properties of chromatic and achromatic regions which is defined according to the HSI color values, and we continue to merge boundary blocks into the adjacent region already segmented to maintain edges until the size of block is one. In the simulation results the proposed method is better than the conventional methods in the evaluation of the segmented regions of texture and edge region, and we found that the processing time is decreased by factor of two in the proposed method.

• Journal of Korea Spatial Information System Society
• /
• v.12 no.1
• /
• pp.37-48
• /
• 2010

In this paper, we analyze the shortcomings of the previous declustering methods, which are based on grid-like partitioning and a mapping function from a cell to a disk number, for high-dimensional space and propose a solution. The problems arise from the fact that the number of splitting is small(for the most part, binary-partitioning is sufficient), and the side length of a range query whose selectivity is small is quite large. To solve this problem, we propose a mathematical model to estimate the performance of a grid-like partitioning method. With the proposed estimation model, we can choose a good grid-like partitioning method among the possible schemes and this results in overall improvement in declustering performance. Several experimental results show that we can improve the performance of a previous declustering method up to 2.7 times.

• Water for future
• /
• v.19 no.2
• /
• pp.139-148
• /
• 1986

The hydrologic response function in a small basin is expressed by the distribution function of slope length. The characteristics of topographical factors is represented to the concentration time, and the instantaneous unit hydrograph is derived as a hydrologic rsponse function by application of probobility density function. The averaging process of runoff characteristics within watershed was analyzed for a few small watershed where was split up the small basin itself. The method of calculation of the effective rainfall should play important roles in the transformation process from hydrologic response function to runoff hydrograph. In this paper, the Horton's infiltration quation is used as a method of calculation of effective rainfall, a new response function of runoff process is derived. The $\Phi$-index method and the infiltration method are tested by comparing the observed and estimated values.