• The Journal of the Acoustical Society of Korea
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• v.10 no.2
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• pp.5-12
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• 1991

In this paper, we have recognized Korean connected-digits. To reduce the processing time the method of combining VQ one-stage DP is introduced and to reduce the number of reference pattern a new group labelling technique is proposed. Group-labelling is a method to segment and label connected-digit into groups by VQ. As experimental results with 3 connected-digits, the number of reference patterns are reduced in proportion to the number of groups which are labelled.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.5
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• pp.1-7
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• 2004

A regular logical topology requires little processing time for routing purposes which may be a desirable property for high-speed networks. Asymmetric bilayered ShuffleNet, proposed by us as a logical topology, can be used to a wavelength division multiplexing ring network to increase the network capacity compared to ShuffleNet. In this paper, asymmetric bilayered ShuffleNet is imbedded on a wavelength division multiplexing ring with the objective of minimizing the total number of wavelengths assigned.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1493-1496
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• 2005

연결형 dominating set기반의 라우팅 알고리즘에서 잦은 dominating set의 재구성은 루트 손실로 인한 전송 에러를 발생시키기 때문에, 노드의 잔여 전력량과 이동성을 고려하여 게이트웨이 노드를 선택하여야 한다. 또한 같은 지역에 노드가 집중되어 있다면 매체를 공유하는 무선 네트워크의 특성상 병목으로 인한 충돌 및 지연 등이 야기 될 가능성이 크다. 따라서 본 논문에서는 노드의 잔여 전력량 및 이동성, 이웃 노드수의 가중 가산 값에 비례하여 이웃 구성 통보 메시지 (neighbor set advertisement message)의 브로드캐스팅을 지연시키는 방법을 통해 연결형 dominating set의 재구성을 최소화 하여 신뢰성 있고 효율적인 데이터 전송을 보장하는 새로운 연결형 dominating set 구성 방법을 제안하고 다양한 상황에서의 실험을 통해 그 성능을 비교 평가하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.11a
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• pp.241-244
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• 2004

일반적으로 메쉬(mesh)는 비정규 연결 형태(irregular connectivity)로 되어 있다. 리메싱(remeshing)은 비정규 연결 형태의 메쉬를 정규 연결 형태(regular connectivity)로 바꾸어 주는 작업이다. 메쉬의 기하 정보가 2D 그리드에 저장이 되어 있는 기하이미지(geometry Images)는 비정규 연결 형태의 메쉬를 완전 정규 형태(completely regular connectivity)로 리메싱하는 데 사용된다. 원본 메쉬를 기하 이미지로 생성하는 방법은 변형되는 크기를 최소화 하는 스트레치 메트릭(stretch metric)을 기반으로 이루어 졌다. 이 방법은 리메싱된 메쉬의 언더샘플링(undersampling)을 줄여 주게 된다. 하지만 리메싱 과정에서 생기는 오버샘플링(oversampling)은 줄여 주지 못한다. 본 논문에서는 정점(vertex)의 법선 벡터(normal vector)를 이용하여 기하이미지의 오버샘플링을 줄이는 방법을 제시한다.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2143-2145
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• 2005

Power semicondcutor인 IGBT MOSFET, GTO, SI-Thyristor등은 높은 스위치 신뢰성과 life time, 그리고 fast repetition rate 등을 지니고 있기 때문에 medium/High voltage영역에서 스위치 사용이 대두되어 왔으나, Thyratron이나 Trigatron(Gap switch)와 비교하여 낮은 전압/전류를 스위칭하기 때문에 전통적으로 직렬연결을 통해 high voltage 영역의 스위치로 사용되어 왔다. 하지만, 직렬연결되어 있는 각각의 power semiconductor와 gate driving circuit의 on/off synchronization이 맞지 않기 때문에 부하의 급격한 변화에 따른 전압의 balance에 문제가 가장 심각하게 대두되어 왔다. 이러한 문제를 해결하기 위해서 gate driving circuit에서 제어를 해주는 방법과 power semiconductor에서 제어를 해주는 방법이 있으나 두 방식 모두 문제점이 있다. 본 논문에서는 기존의 zener clamping방식에서 벗어나 새로운 active clamping방식의 직렬연결을 제안했으며 시뮬레이션과 실험을 통해 나타난 이 결과들은 on/off transient 시 symmetry를 유지하는데 효과적이라는 것을 보여주고 있다.

• Journal of KIISE:Software and Applications
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• v.30 no.10
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• pp.904-911
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• 2003

In this paper, we propose an effective method for the distinction between machine-printed and handwritten Korean address images. It is important to know whether an input image is handwritten or machine-printed, because methods for handwritten image are quite different from those of machine-printed image in such applications as address reading, form processing, FAX routing, and so on. Our method consists of three blocks: valid connected components grouping, feature extraction, and classification. Features related to width and position of groups of valid connected components are used for the classification based on a neural network. The experiment done with live Korean address images has demonstrated the superiority of the proposed method. The correct classification rate for 3,147 testing images was about 98.85%.

• The Korean Journal of Applied Statistics
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• v.31 no.4
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• pp.517-528
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• 2018

We provide R scripts to detect outliers in multivariate data and visualization. Detecting outliers is provided using three approaches 1) Robust Mahalanobis distance, 2) High Dimensional data, 3) density-based approach methods. We use the following techniques to visualize detected potential outliers 1) multidimensional scaling (MDS) and minimal spanning tree (MST) with k-means clustering, 2) MDS with fviz cluster, 3) principal component analysis (PCA) with fviz cluster. For real data sets, we use MLB pitching data including Ryu, Hyun-jin in 2013 and 2014. The developed R scripts can be downloaded at "http://www.knou.ac.kr/~sskim/ddpoutlier.html" (R scripts and also R package can be downloaded here).

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.4
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• pp.263-270
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• 2020

This study evaluates the structural behavior of connected long-span beams applied for excavation in urban areas with a narrow street. Generally, the reliability of the connection is reduced owing to the defect of the upper flange in the connection. An improved connection part was developed to complement the defects in the connected long-span beam. A finite element analysis based on a commercial program, ABAQUS, was employed to evaluate the behavior of the improved connection part. A numerical analysis model was proposed to analyze the high-strength bolt connection and the composite behavior of steel and concrete applied to the improved connection. The suitability of the proposed numerical analysis was verified by comparing the experimental and numerical analysis results of the references. Using the proposed numerical analysis method, the improved and general connections were analyzed and compared with each other. The stress distribution and elastic-plastic behavior of the long-span beam were analyzed numerically. The analysis confirmed that 25% of the compressive stress was improved, resulting in the improvement of structural safety and performance.

• 한국HCI학회:학술대회논문집
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• 2008.02b
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• pp.456-459
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• 2008

We are now in the era of digital convergence with CE products and PC at the center, but product diversification occurs in the same breath. Each device may perform its own functions itself independently, but proportion of the inter-device usage is increasing gradually by concept of a home network and ubiquitous widely prevailed. The consumer's need of inter-device connection will take the dominative position of the market. Therefore, we can easily forecast that diversification of the products may inevitably lead connectivity patterns complicated considering recent market situation and trends. In this paper, we propose the methodology for designing inter-device connectivity which covers issues such like segmenting numerous number of connectivity pattern, and establishing their structure of control. Our methodology also supports the inter-device connection with extensive latitudes and a multi-device simultaneous control. In order to present inter-device connectivity guideline, we define four stages of a user experience - Connection, Configuration, Use, Disconnection. Based on the 4 user experience stages, we suggest a specific connectivity designing guideline for each step.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.3
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• pp.316-321
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• 2007

We propose a quatitative annotation method for edges in Bayesian networks using given sets of condition-specific data. Bayesian network model has been used widely in various fields to infer probabilistic dependency relationships between entities in target systems. Besides the need for identifying dependency relationships, the annotation of edges in Bayesian networks is required to analyze the meaning of learned Bayesian networks. We assume the training data is composed of several condition-specific data sets. The contribution of each condition-specific data set to each edge in the learned Bayesian network is measured using the ratio of likelihoods between network structures of including and missing the specific edge. The proposed method can be a good approach to make quantitative annotation for learned Bayesian network structures while previous annotation approaches only give qualitative one.