• 대한전기학회논문지:전력기술부문A
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• 제52권11호
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• pp.639-646
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• 2003

Nowadays traction motors in the urban rail transit vehicle are controlled by VVVF inverter and have capability of regenerative braking. The algorithms to deal with the regenerating vehicle in simulation for the DC traction power supply is introduced in this paper. Substations have to be separated from the system to represent reverse biased rectifiers in substations. The model of the trains in regenerative braking has to be changed from the ideal current source to the constant voltage source since the train input voltage has to be controlled below the certain train maximum voltage. Some mismatches are unevitable because the constraint of the regenerated power can not be imposed with the constant voltage source. The mismatches represent the unused regenerated power. A computer program is developed to verify the validity of the algorithm. The test run result shows the program behaves as it is expected and proves the algorithm's validity.

• 대한기계학회논문집
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• 제18권1호
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• pp.12-23
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• 1994

This paper proposes an optimal design software for the open-chain dynamic systems whose governing equations are expressed as differential equation. In this software, an input module and an automatic creation module of the equation of motion are developed to contrive the user's convenience. To analyze the equation of motion of the dynamic systems, variable-order and variable-stepsize Adams-Bashforth-Moulton predictor-corrector method is used to improve the efficiency. For the optimization and the design sensitivity analysis, ALM(augmented lagrange multiplier)method and adjoint variable method are adopted respectively. An output module with which the user can compare and investigate the analysis and the optimization results through tables and graphs is also provided. The developed software is applied to three typical dynamic response optimization problems, and the results compare very well with those available in the literature, demonstrating its effectiveness.

• 산업경영시스템학회지
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• 제21권46호
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• pp.119-125
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• 1998

In this study, a traditional concept of sampling inspection plan for the quality assurance system is extended to a consideration of economic aspects in total production system by representing and analyzing the effects between proceeding / succeeding production process including inspection. This approach recognizes that the decision to be made at one manufacturing process (or assembly process) determine not only the cost and the average outgoing quality level of that process but also the input parameters of the cost and the incoming quality to the succeeding process. By analyzing the effects of the average incoming and outgoing quality, manufacturing / assembly quality level and sampling inspection plan on the production system, mathematical models and solution technique to minimize the total production cost for a single product manufacturing system with specified average outgoing quality limit(AOQL) are suggested.

• 한국멀티미디어학회:학술대회논문집
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• 한국멀티미디어학회 2003년도 춘계학술발표대회논문집
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• pp.423-426
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• 2003

Adaptive algorithm used in Acoustic Echo Canceller (AEC) needs fast convergence algorithm when reference signal is colored speech signal. Set-Membership Affine Projection (SMAP) algorithm is derived from the constraint, which is the minimum value adaptive filter coefficient error. In this paper, we test the characteristic about noise of the SMAP algorithm and proposed modified version of SMAP algorithm fur using at AEC. As the projection order increase, the convergence characteristic of the SMAP algorithm is improved where no noise space. But if the noise uncorrelated with input signal exists, the AEC shows bad performance. In this paper, we propose normalized version of adaptive constants using estimated error signal for robust to noise and show the good performance through AEC simulation.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2019년도 추계학술발표대회
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• pp.795-797
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• 2019

In this paper, we propose a method to generate adversarial examples for toxicity detection neural networks. Our dataset is represented by a one-hot vector and we constrain that only one character is allowed to be modified. The location to be changed is founded by the maximum area of input gradient, which represents the most affecting character the model to make decisions. Despite the fact that we have strong constraint compared to the image-based adversarial attack, we have achieved about 49% successful rate.

• 한국멀티미디어학회논문지
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• 제22권2호
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• pp.210-224
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• 2019

Given a positive integer k as input, a spatial preference query finds the k best data objects based on the scores (e.g., qualities) of feature objects in their spatial neighborhoods. Several solutions have been proposed for spatial preference queries in Euclidean space. A few algorithms study spatial preference queries in undirected spatial networks where each edge is undirected and the distance between two points is the length of the shortest path connecting them. However, spatial preference queries have not been thoroughly investigated in directed spatial networks where each edge has a particular orientation that makes the distance between two points noncommutative. Therefore, in this study, we present a new method called ALPS+ for processing spatial preference queries in directed spatial networks. We conduct extensive experiments with different setups to demonstrate the superiority of ALPS+ over conventional solutions.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권11호
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• pp.4463-4482
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• 2020

Mesh model generated from 3D reconstruction usually comes with lots of noise, which challenges the performance and robustness of mesh simplification approaches. To overcome this problem, we present a novel method for mesh simplification which could preserve structure and improve the accuracy. Our algorithm considers both the planar structures and linear features. In the preprocessing step, it automatically detects a set of planar structures through an iterative diffusion approach based on Region Seed Growing algorithm; then robust linear features of the mesh model are extracted by exploiting image information and planar structures jointly; finally we simplify the mesh model with plane constraint QEM and linear feature preserving strategies. The proposed method can overcome the known problem that current simplification methods usually degrade the structural characteristics, especially when the decimation is extreme. Our experimental results demonstrate that the proposed method, compared to other simplification algorithms, can effectively improve the quality of mesh and yield an increased robustness on noisy input mesh.

• 스마트미디어저널
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• 제12권6호
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• pp.9-14
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• 2023

최장 증가 부분서열(longest increasing subsequence)은 컴퓨터 과학 분야에서 오랫동안 연구되어온 주요 문제이다. 본 논문에서는 최장 조건을 극대로 완화한 극대 증가 부분서열(maximal increasing subsequence) 문제를 고려한다. 본 논문에서는 두 가지 버전의 증가 개념(단조증가, 순증가)에 대해, 알파벳 Σ 에 대한 서열의 극대 증가 부분서열을 구하는 선형시간 알고리즘을 제안한다. 극대 단조증가 부분서열을 구하는 알고리즘은 O(1) 공간을 사용하고, 극대 순증가 부분서열을 구하는 알고리즘은 O(|Σ|) 공간을 사용한다.

• 정보처리학회논문지B
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• 제13B권5호
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• pp.547-552
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• 2006

클래스의 속성과 메소드 참조관계를 고려한 응집도 측정 방법은 다양한 형태로 연구되어 왔다 이러한 응집도의 측정 방법은 일반적으로 하나의 클래스에서 이루어진다. 단일 클래스에서 두 개의 클래스로 참조 범위를 확장하면 두 클래스 사이에 발생할 수 있는 참조관계를 알 수 있다. 본 논문에서는 메소드의 위치 결정을 위하여 신경망 학습모델을 제안하였다. 신경망은 입출력 패턴에 대한 반복학습 후, 학습 패턴에 포함되지 않았던 입력 패턴의 목적 값을 예측하고, 일반화(generalization)하는데 효과적이다. 두 개의 클래스 안의 속성과 메소드를 5개 이하로 제한하였고, 학습 벡터는 30개의 이진 값으로 구성된 입력 벡터와 메소드 위치 결정 값인 이진 목적 값으로 생성되었다. 제안된 신경망은 교차검증에서 약 95%, 테스트 데이터에 대해서는 약88%의 예측율을 보였다.

• 정보관리연구
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• 제38권1호
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• pp.75-98
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• 2007

인터넷이 발달함에 따라 기하급수적으로 늘어나는 각 서비스 도메인들은 그들만의 특성에 맞는 서비스를 제공하여 그에 따른 부가가치를 창출하고 있다. 또한 각 도메인 내에는 업무의 특성별로 서비스가 구분되며 서비스를 제공받기 위해서는 현실적으로 대부분 개인의 인력정보를 제공해야 하며, 그렇지 않으면 서비스를 일부 제한받거나 전혀 받을 수 없다. 본 논문에서는 서비스 제공기관에서 요구하는 인력정보를 분석하여 공통 항목에 대하여 중복입력을 방지하고 공동 활용할 수 있는 에이전트 설계 및 구현방법에 대해 제시하고자 하였다.