두 점과 분할 카디날리티가 주어진 퍼지 균등화조건을 갖는 퍼지분할

김경택(Kyeongtaek Kim)․,김종수(Chong Su Kim)․,강성열(Sungyeol Kang) 한국산업경영시스템학회 2008 한국산업경영시스템학회지 Vol.31 No.4

Fuzzy partition is a conceptual vehicle that encapsulates data into information granules. Fuzzy equalization concerns a process of building information granules that are semantically and experimentally meaningful. A few algorithms generating fuzzy partitions with fuzzy equalization have been suggested. Simulations and experiments have showed that fuzzy partition representing more characteristics of given input distribution usually produces meaningful results. In this paper, given two points and cardinality of fuzzy partition, we prove that it is not true that there always exists a fuzzy partition with fuzzy equalization in which two of points having peaks fall on the given two points. Then, we establish an algorithm that minimizes the maximum distance between given two points and adjacent points having peaks in the partition. A numerical example is presented to show the validity of the suggested algorithm.

구간 데이터를 위한 가변정밀도 러프집합 모형

김경택(Kyeongtaek Kim) 한국산업경영시스템학회 2011 한국산업경영시스템학회지 Vol.34 No.2

Variable precision rough set models have been successfully applied to problems whose domains are discrete values. However, there are many situations where discrete data is not available. When it comes to the problems with interval values, no variable precision rough set model has been proposed. In this paper, we propose a variable precision rough set model for interval values in which classification errors are allowed in determining if two intervals are same. To build the model, we define equivalence class, upper approximation, lower approximation, and boundary region. Then, we check if each of 11 characteristics on approximation that works in Pawlak’s rough set model is valid for the proposed model or not.

An Application of Quantum-inspired Genetic Algorithm for Weapon Target Assignment Problem

Jung Hun Kim(김정훈),Kyeongtaek Kim(김경택),Bong-Wan Choi(최봉완),Jae Joon Suh(서재준) 한국산업경영시스템학회 2017 한국산업경영시스템학회지 Vol.40 No.4

Quantum-inspired Genetic Algorithm (QGA) is a probabilistic search optimization method combined quantum computation and genetic algorithm. In QGA, the chromosomes are encoded by qubits and are updated by quantum rotation gates, which can achieve a genetic search. Asset-based weapon target assignment (WTA) problem can be described as an optimization problem in which the defenders assign the weapons to hostile targets in order to maximize the value of a group of surviving assets threatened by the targets. It has already been proven that the WTA problem is NP-complete. In this study, we propose a QGA and a hybrid-QGA to solve an asset-based WTA problem. In the proposed QGA, a set of probabilistic superposition of qubits are coded and collapsed into a target number. Q-gate updating strategy is also used for search guidance. The hybrid-QGA is generated by incorporating both the random search capability of QGA and the evolution capability of genetic algorithm (GA). To observe the performance of each algorithm, we construct three synthetic WTA problems and check how each algorithm works on them. Simulation results show that all of the algorithm have good quality of solutions. Since the difference among mean resulting value is within 2%, we run the nonparametric pairwise Wilcoxon rank sum test for testing the equality of the means among the results. The Wilcoxon test reveals that GA has better quality than the others. In contrast, the simulation results indicate that hybrid-QGA and QGA is much faster than GA for the production of the same number of generations.

무기할당 모형을 이용한 탄도미사일 방어

장준건(Jun-Gun Jang),김경택(Kyeongtaek Kim),최봉완(Bong-Wan Choi) 한국산업경영시스템학회 2015 한국산업경영시스템학회 학술대회 Vol.2015 No.추계

When offense launches missiles at valuable assets of the defense, the defense must assign its weapons to these missiles so as to maximize the total value of surviving assets threatened by them. Recently, a new asset-based linear approximation model was proposed for weapon target assignment problem with shootlook- shoot engagement policy and fixed set-up time between each anti-missile launch from each defense unit. In this paper, we apply the proposed to several ballistic missile defense examples and we show their weapon target assignment results specified with launch order time.

자산기반 무기할당 문제의 선형 근사 모형

장준건(Jun-Gun Jang),김경택(Kyeongtaek Kim),최봉완(Bong-Wan Choi),서재준(Jae Joon Suh) 한국산업경영시스템학회 2015 한국산업경영시스템학회지 Vol.38 No.3

A missile defense system is composed of radars detecting incoming missiles aiming at defense assets, command control units making the decisions on weapon target assignment, and artillery batteries firing of defensive weapons to the incoming missiles. Although, the technology behind the development of radars and weapons is very important, effective assignment of the weapons against missile threats is much more crucial. When incoming missile targets toward valuable assets in the defense area are detected,the asset-based weapon target assignment model addresses the issue of weapon assignment to these missiles so as to maximize the total value of surviving assets threatened by them. In this paper, we present a model for an asset-based weapon assignment problem with shoot-look-shoot engagement policy and fixed set-up time between each anti-missile launch from each defense unit. Then, we show detailed linear approximation process for nonlinear portions of the model and propose final linear approximation model. After that, the proposed model is applied to several ballistic missile defense scenarios. In each defense scenario, the number of incoming missiles, the speed and the position of each missile, the number of defense artillery battery, the number of anti-missile in each artillery battery, single shot kill probability of each weapon to each target, value of assets, the air defense coverage are given. After running lpSolveAPI package of R language with the given data in each scenario in a personal computer, we summarize its weapon target assignment results specified with launch order time for each artillery battery. We also show computer processing time to get the result for each scenario.

딥러닝을 이용한 핸드크림의 마찰 시계열 데이터 분류

김지원(Ji Won Kim),이유민(You Min Lee),한상헌(Shawn Han),김경택(Kyeongtaek Kim) 한국산업경영시스템학회 2021 한국산업경영시스템학회지 Vol.44 No.3

The sensory stimulation of a cosmetic product has been deemed to be an ancillary aspect until a decade ago. That point of view has drastically changed on different levels in just a decade. Nowadays cosmetic formulators should unavoidably meet the needs of consumers who want sensory satisfaction, although they do not have much time for new product development. The selection of new products from candidate products largely depend on the panel of human sensory experts. As new product development cycle time decreases, the formulators wanted to find systematic tools that are required to filter candidate products into a short list. Traditional statistical analysis on most physical property tests for the products including tribology tests and rheology tests, do not give any sound foundation for filtering candidate products. In this paper, we suggest a deep learning-based analysis method to identify hand cream products by raw electric signals from tribological sliding test. We compare the result of the deep learning-based method using raw data as input with the results of several machine learning-based analysis methods using manually extracted features as input. Among them, ResNet that is a deep learning model proved to be the best method to identify hand cream used in the test. According to our search in the scientific reported papers, this is the first attempt for predicting test cosmetic product with only raw time-series friction data without any manual feature extraction. Automatic product identification capability without manually extracted features can be used to narrow down the list of the newly developed candidate products.

유도가열을 활용한 동절기 콘크리트의 발열양생 효율성 평가

이진복(Lee, Jinbok),김경택(Kim, Kyeongtaek),최진수(Choi, Jinsoo),안치형(Ahn, Chi-Hyung),신현오(Shin, Hyun-Oh) 한국방재학회 2020 한국방재학회논문집 Vol.20 No.6

본 연구에서는 유도가열 기법을 활용한 동절기 콘크리트의 발열양생 효율성을 평가하였다. 거푸집의 크기 및 형태에 따른거푸집 콘크리트 발열성능을 검증하였으며, 콘크리트 배합 종류별 발열양생 효율성을 양생 후 압축강도 비교를 통해 평가하였다. 실험결과, 콘크리트 및 거푸집의 단면적이 증가할수록 유도가열에 의한 콘크리트 중심부 및 외부 거푸집의 온도분포 차이가발생하여 전단면의 고른 양생이 어려움을 확인하였다. 이러한 문제는 단면 내부에 추가로 유도 및 열전달이 가능한 재료를넣어줌으로 인해 보완이 가능함을 확인하였다. 0 ℃의 저온 챔버에서 거푸집 유도에 의해 가열 양생된 콘크리트는 15시간에충분한 조기강도를 확보하였으며, 물/시멘트 비가 감소할수록 온도증가에 의한 수화 가속효과가 증가하여 강도증진 효과가향상되었다. 추가적으로, 본 연구에서는 유도가열 시 발생할 수 있는 전자파에 의한 인체 유해성을 평가하였으며, 실험결과유도가열양생 과정에서 발생한 자속밀도 평균은 13.9 μT로 전자파 적합성기준을 만족하였다. In this study, we evaluated the heat curing performance of cold-weather concrete using the induction heating technology. Specifically, we studied the effects of the size and shape of steel forms as well as different concrete mixtures on the heat curing performance. The test results showed that increasing the cross-section of concrete reduced the homogeneity of temperature distribution throughout it. This problem can be compensated for by adding more conductive materials in the concrete cross-section. The concrete specimens that were cured using induction heating achieved a satisfactory early age strength even though they were stored in a 0 °C low-temperature chamber. Furthermore, we evaluated the electromagnetic compatibility (EMC) of the induction heating process and the magnetic flux density of 13.9 μT thus obtained satisfied the EMC requirement.

An Analysis of Quality Efficiency of Loan Consultants in a Bank using Shannon’s Entropy and PCA-DEA Model

Jang Ki Choi(최장기0,Kyeongtaek Kim(김경택),Jae Joon Suh(서재준) 한국산업경영시스템학회 2017 한국산업경영시스템학회지 Vol.40 No.3

Loan consultants assist clients with loan application processing and loan decisions. Their duties may include contacting people to ask if they want a loan, meeting with loan applicants and explaining different loan options. We studied the efficiency of service quality of loan consultants contracted to a bank in Korea. They do not work as a team, but do work independently. Since he/she is not an employee of the bank, the consultant is paid solely in proportion to how much he/she sell loans. In this study, a consultant is considered as a decision making unit (DMU) in the DEA (Data Envelopment Analysis) model. We use a principal component analysis-data envelopment analysis (PCA-DEA) model integrated with Shannon’s Entropy to evaluate quality efficiency of the consultants. We adopt a three-stage process to calculate the efficiency of service quality of the consultants. In the first stage, we use PCA to obtain 6 synthetic indicators, including 4 input indicators and 2 output indicators, from survey results in which questionnaire items are constructed on the basis of SERVQUAL model. In the second stage, 3 DEA models allowing negative values are used to calculate the relative efficiency of each DMU. In the third stage, the weight of each result is calculated on the basis of Shannon’s Entropy theory, and then we generate a comprehensive efficiency score using it. An example illustrates the proposed process of evaluating the relative quality efficiency of the loan consultants and how to use the efficiency to improve the service quality of the consultants.

혼입재료에 따른 유도가열 기반 발열양생 콘크리트의 특성

이진복 ( Jinbok Lee ),김경택 ( Kyeongtaek Kim ),최진수 ( Jinsoo Choi ),조승환 ( Seunghwan Jo ),신현오 ( Hyun-oh Shin ) 한국농공학회 2020 한국농공학회 학술대회초록집 Vol.2020 No.-

본 연구에서는 피가열체를 전자기유도에 의해 직접 가열하는 유도가열기반 발열양생기법의 효율성을 평가하였다. 특히 외부 거푸집을 통해 발열양생을 실시하는 것 뿐 아니라 콘크리트 내부에 전도체인 강섬유와 전기로산화슬래그를 혼입하여, 이의 유도가열 양생 성능을 평가하고 SEM 촬영을 통해 미세구조를 분석하였다. 본 실험에 앞서서 콘크리트에 혼입되는 전도체인 강섬유와 전기로산화슬래그 자체의 유도성능을 평가하였으며, 실험결과 재료 자체의 유도성능은 강섬유가 전기로산화슬래그 보다 높지만 두 종류의 혼입재료 모두 유도가열에 적합함이 확인되었다. 강섬유와 전기로산화슬래그의 혼입률에 따른 유도가열양생 성능을 평가하기 위하여 갈고리형 강섬유(Hooked-End Steel Fiber)를 콘크리트의 1vol.% 및 2vol.% 혼입하였으며, 전기로산화슬래그는 잔골재의 50%를 대체하여 혼입하였다. 실험결과는 상온양생과 유도가열양생을 비교하였으며, 15시간 양생을 기준으로 압축강도를 평가하였다. 실험결과 상온양생 실험체 대비 유도가열양생 실험체의 압축강도가 기본배합의 경우 168%를 나타내었으며, 강섬유를 1% 및 2% 혼입한 배합에서는 193% 및 189%로 증가하는 것을 확인할 수 있었다. 전기로산화슬래그를 잔골재의 50% 대체한 배합의 경우, 상온양생 대비 187%의 압축강도 발현률을 나타내었다. 이를 통해 콘크리트 내부 전도체 혼입은 유도효율을 증대시켜 전체적인 유도가열 양생성능을 향상시키는 것으로 확인되었다.

근사적 동적계획을 활용한 요격통제 및 동시교전 효과분석

이창석(Changseok Lee),김주현(Ju-Hyun Kim),최봉완(Bong Wan Choi),김경택(Kyeongtaek Kim) 한국항공우주학회 2022 韓國航空宇宙學會誌 Vol.50 No.4

저고도 궤적의 장사정포 위협이 대두됨에 따라 이를 방어할 요격 시스템의 개발이 시작될 예정이다. 이러한 장사정포의 공격을 방어하는 문제는 전형적인 동적 무기 표적 할당 문제다. 동적 무기 표적 할당 문제에서는 한 시점에서의 의사결정 결과가 이후 시점의 의사결정 과정에 영향을 주며, 이는 마코브 의사결정 모형의 특징이기도 하다. 장사정포의 공격을 방어하기 위한 의사결정 과정에 허용되는 시간은 공격자와 방어자의 거리를 고려할 때 저고도 궤적의 동시 다발성 발사체에 대한 대응은 수 초 이내에 결정되어야 하나, 짧은 시간 내에 마코브 의사결정 과정으로 최적해를 구하는 것은 불가능하다. 본 논문에서는 장사정포 공격을 방어하는 동적 무기 표적 할당 문제를 마코브 의사결정 문제로 나타내고, 3가지 시나리오를 작성한 후 근사적 동적계획 방법을 적용하여 요격이 가능 시간 안에 해의 도출이 가능한지를 시뮬레이션을 통하여 확인하였다. 도출된 해의 품질을 검증하기 위하여 각 시나리오에 대하여 근사적 동적계획을 적용한 결과와 Shoot-Shoot-Look 방법을 적용한 결과를 비교하였다. 시뮬레이션 결과, 장사정포의 방어 시나리오에 대하여 근사적 동적계획의 결과가 Shoot-Shoot-Look 방법을 이용한 결과보다 우수함을 보였다. As low altitude long-range artillery threat has been strengthened, the development of anti-artillery interception system to protect assets against its attacks will be kicked off. We view the defense of long-range artillery attacks as a typical dynamic weapon target assignment (DWTA) problem. DWTA is a sequential decision process in which decision making under future uncertain attacks affects the subsequent decision processes and its results. These are typical characteristics of Markov decision process (MDP) model. We formulate the problem as a MDP model to examine the assignment policy for the defender. The proximity of the capital of South Korea to North Korea border limits the computation time for its solution to a few second. Within the allowed time interval, it is impossible to compute the exact optimal solution. We apply approximate dynamic programming (ADP) approach to check if ADP approach solve the MDP model within processing time limit. We employ Shoot-Shoot-Look policy as a baseline strategy and compare it with ADP approach for three scenarios. Simulation results show that ADP approach provide better solution than the baseline strategy.