• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.81-82
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• 2020

Non-convex 최적화 문제의 복잡도를 완화하도록 해주는 오목함수 결정규칙을 제안한다. 전송용량을 나타내는 유틸리티 함수는 신호와 간섭의 함수이며, non-convex이다. 유틸리티 함수를 간섭관점에서 분석한다. '상대간섭'과 '간섭주요화'를 정의한다. 상대간섭은 D2D 수신단에서의 간섭레벨을 나타낸다. 간섭주요화는 간섭을 주요간섭으로 간략화한다. 간섭주요화를 기반으로 하는 오목함수 결정규칙을 제안한다. 실험결과를 통하여 유틸리티 함수는 상대간섭 0.1 이하에서는 오목함수임을 확인하였다.

• The KIPS Transactions:PartC
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• v.12C no.7 s.103
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• pp.1007-1014
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• 2005

A generation of rules or patterns for detecting attacks from network is very difficult. Detection rules and patterns are usually generated by Expert's experiences that consume many man-power, management expense, time and so on. This paper proposes statistical methods that effectively detect intrusion and attacks without expert's experiences. The methods are to select useful measures in measures of network connection(session) and to detect attacks. We extracted the network session data of normal and each attack, and selected useful measures for detecting attacks using relative entropy. And we made probability patterns, and detected attacks using likelihood ratio testing. The detecting method controled detection rate and false positive rate using threshold. We evaluated the performance of the proposed method using KDD CUP 99 Data set. This paper shows the results that are to compare the proposed method and detection rules of decision tree algorithm. So we can know that the proposed methods are useful for detecting Intrusion and attacks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.7A
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• pp.1017-1027
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• 2000

In this paper, we propose a new coding method based on the distance between vertex segments for vertex positions in the vertex-based shape coding. The pixel lines are divided into the segments of a fixed length, and the segments that have vertex pixels are called vertex segments. We analyze the probability distribution of the relative distance between vertex segments and prove that it depends only on the ratio between the number of vertices and the number of segments. Considering the coding efficiency and implementation complexity, we choose a particular ratio to make a code table. For each input image, the segment size is chosen according tothe ratio, and the relative segment distances are entropy coded. It is shown that the proposed method is efficient for the images with many vertices.

• Journal of the Korea Society of Computer and Information
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• v.25 no.7
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• pp.75-83
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• 2020

We consider the D2D utility optimization problem in the cellular system. More specifically, we develop a concave function decision rule which reduces the complexity of non-convex optimization problem. Typically, utility function, which is a function of the signal and the interference, is non-convex. In this paper, we analyze the utility function from the interference perspective. We introduce the 'relative interference' and the 'interference majorization'. The relative interference captures the level of interference at D2D receiver's perspective. The interference majorization approximates the interference by applying the major interference. Accordingly, we propose a concave function decision rule, and the corresponding convex optimization solution. Simulation results show that the utility function is concave when the relative interference is less than 0.1, which is a typical D2D usage scenario. We also show that the proposed convex optimization solution can be applied for such relative interference cases.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.91-93
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• 2005

대용량 데이타에 대한 복잡한 질의 처리가 요구되는 응용에서 빠른 시간 안에 응답을 돌려주기 위해, 데이타를 작은 크기로 근사하여 질의를 처리하는 방법이 연구되고 있다. 빠른 응답을 위해 주어진 저장 공간의 제약 하에서 얼마나 원본 데이타와 유사하게 근사할 수 있는지가 데이타 근사의 성능을 결정한다. 본 논문에서는 데이타 근사에서 유사도의 척도 중 하나인 최대 상대 오차를 줄이기 위하여 Haar 웨이블릿을 변형한 조화 웨이블릿 기법을 제안한다. 조화 웨이블릿은 데이타 변환 과정 중 조화평균을 이용하여 상대 오차 정보를 손쉽게 얻어낼 수 있어 근사 데이타의 상대 오차를 최소화하는 데 적합한 기법이다.

• Broadcasting and Media Magazine
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• v.7 no.3
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• pp.75-82
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• 2002

In this report, the complexity analysis of the JVT(Joint Video Team) codec, which has jointly developed the next video coding standard, is performed. Three types of configurations in terms of coding efficiency are set and the analysis of the memory band width and computation time for each configuration is performed. ATOMIUM complexity analysis tool is used for both the memory access statistics and computation time calculation of JVT codec. Also the complexity of each video coding tool in the encoder and decoder is shown in relative complexity.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.14 no.24
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• pp.71-81
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• 1991

인체의 운동은 많은 수의 자유도를 지닌 조인트(JOINT)와 링(LINK)의 복잡한 운동으로 표현될 수 있다. 이들 링크(LINK)의 회전 운동은 SINE, COSINE 자승 형태의 비선형 운동으로 이루어져있으나, 최근 PERSONAL COMPUTER의 발달로 복잡한 인체 운동의 수학적 모델에 대한 동력학적 DATA 계산이 가능해졌다. 본 연구에서는 5개의 링크(LINK)로 연결된 인체 움직임에 있어 링크(LINK)의 절대 운동(ABSOLUTE MOTION) 및 상대운동(RELATIVE MOTION)을 고려한 PLAGENHOEF의 운동 모델을 PERSONAL COMPUTER를 이용하여 인체 움직임의 동력학적 DATA를 얻을 수 있도록 BASIC 언어로 프로그램을 제기하였다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.14 no.23
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• pp.7-18
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• 1991

인체의 운동은 많은 수의 자유도를 지닌 조인트(JOINT)와 링(LINK)의 복잡한 운동으로 표현될 수 있다. 이들 링크(LINK)의 회전 운동은 SINE, COSINE 자승 형태의 비선형 운동으로 이루어져있으나, 최근 PERSONAL COMPUTER의 발달로 복잡한 인체 운동의 수학적 모델에 대한 동력학적 DATA 계산이 가능해졌다. 본 연구에서는 5개의 링크(LINK)로 연결된 인체 움직임에 있어 링크(LINK)의 절대 운동(ABSOLUTE MOTION) 및 상대운동(RELATIVE MOTION)을 고려한 PLAGENHOEF의 운동 모델을 PERSONAL COMPUTER를 이용하여 인체 움직임의 동력학적 DATA를 얻을 수 있도록 BASIC 언어로 프로그램을 제기하였다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.4
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• pp.422-429
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• 2018

To make students recognize the danger of fire smoke that may occur in ships and to improve the response capability, spaces for safety educ ation were built inside the training ship, and scenarios were developed. This study is an analysis of the movement characteristics of the students acquire d under each scenario. Followings are the summary of the analysis results. In the non-smoke environments, there was no difference in the velocity of escape movement between the case of without block on the familiar route and the case of with unexpected block. However, when the indoor was filled with smoke, the visibility became very low because of the smoke density and the average velocity was 62.5 % slower than the case where it was not. Regardless of the scenarios, the average equivalent velocity on the complex path was faster than the simple straight path, and the standard deviation was smaller. Under the smoke-fullfilled environment, although the relative velocity probability distributions of the complex passage and the entire passag e are very similar, the inter-individual fluctuation of the relative velocity ratio of the complex passage to that of the entire passage was very large. On the other hand, equivalent velocity could be expressed by the logarithmic function of the visibility. Also, as the tension of the students increased, the equivalent velocities were accelerated on all scenarios.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.11
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• pp.995-1004
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• 2011

Object X-ray method commonly used for hole search in overset grids requires huge amount of time due to complicated vector calculations to search the cross-points as well as time-consuming hole search algorithm with respect to background grids. Especially, when the grid system is in motion relative to the background, hole points should be searched at every time step, leading to hung computational burden. To cope with this difficulties, this study presents an efficient hole search algorithm mainly designed to reduce hole searching time. To this end, virtual surface with reduced grid points is suggested and logical operators are employed as a classification algorithm instead of complicated vector calculations. In addition, the searching process is further accelerated by designating hole points in a row rather than discriminating hole points with respect to each background grid points. If there exists a relative motion, the present algorithm requires much less time because only the virtual surface needs to be moved at every time step. The hole searching time has been systematically compared for a few selected geometries.