• The KIPS Transactions:PartC
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• v.8C no.6
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• pp.731-740
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• 2001

Multi-distributed web cluster model expanding conventional cluster system is the cluster system which processes large-scaled work demanded from users with parallel computing method by building a number of system nodes on open network into a single imaginary network. Multi-distributed web cluster model on the structured characteristics exposes internal system nodes by an illegal third party and has a potential that normal job performance is impossible by the intentional prevention and attack in cooperative work among system nodes. This paper presents the mutual authentication protocol of system nodes through key division method for the authentication of system nodes concerned in the registration, requirement and cooperation of service code block of system nodes and collecting the results and then designs SNKDC which controls and divides symmetrical keys of the whole system nodes safely and effectively. SNKDC divides symmetrical keys required for performing the work of system nodes and the system nodes transmit encoded packet based on the key provided. Encryption packet given and taken between system nodes is decoded by a third party or can prevent the outflow of information through false message.

• The Transactions of the Korea Information Processing Society
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• v.6 no.4
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• pp.1045-1057
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• 1999

Packet-switched multistage interconnection networks(MINs) have been widely used for digital switching systems and super computers. In this paper we show that multiple packets in a switching element can move to the succeeding switching element in one network cycle by fully utilizing the cycle bandwidth. Only one packet movement was usually assumed in typical MINs. we present an analytical model for the MNs with the multiple packet movement scheme, and validate it by computer simulation. Comparisons with the traditional MINs of single packet movement reveal that the throughput is increased up to about 30% for practical size MINs. Similar result was also obtained for delays. The performance increase is more significant when the network traffic is nonuniform.

• Investigative Magnetic Resonance Imaging
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• v.3 no.2
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• pp.179-187
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• 1999

Purpose : This paper introduces a computationally inexpensive context-dependent classification of multi-echo MRI with Bayes compound decision model. In order to produce accurate region segmentation especially in homogeneous area and along boundaries of the regions, we propose a classification method that uses contextual information of local enighborhood system in the image. Material and Methods : The performance of the context free classifier over a statistically heterogeneous image can be improved if the local stationary regions in the image are disassociated from each other through the mechanism of the interaction parameters defined at he local neighborhood level. In order to improve the classification accuracy, we use the contextual information which resolves ambiguities in the class assignment of a pattern based on the labels of the neighboring patterns in classifying the image. Since the data immediately surrounding a given pixel is intimately associated with this given pixel., then if the true nature of the surrounding pixel is known this can be used to extract the true nature of the given pixel. The proposed context-dependent compound decision model uses the compound Bayes decision rule with the contextual information. As for the contextual information in the model, the directional transition probabilities estimated from the local neighborhood system are used for the interaction parameters. Results : The context-dependent classification paradigm with compound Bayesian model for multi-echo MR images is developed. Compared to context free classification which does not consider contextual information, context-dependent classifier show improved classification results especially in homogeneous and along boundaries of regions since contextual information is used during the classification. Conclusion : We introduce a new paradigm to classify multi-echo MRI using clustering analysis and Bayesian compound decision model to improve the classification results.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.681-682
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• 2006

일반적으로 축구 비디오 데이터는 멀티모달과 멀티레이어 속성을 지닌다. 이러한 데이터를 다루기 적합한 모델은 동적 베이지안 네트워크(Dynamic Bayesian Network: DBN) 형태의 위계적 은닉 마르코프 모델(Hierarchical Hidden Markov Model: HHMM)이다. 이러한 HHMM 중 다중속성의 특징들이 서로 상호작용하는 PHHMM(Product Hierarchical Hidden Markov Model)이 있다. 본 논문에서는 PHHMM 을 축구 경기의 Play/Break 이벤트 검색 및 분석에 적용하였고 바람직한 결과를 얻었다.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.11a
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• pp.441-446
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• 2001

본 논문에서는 다중 사용자간의 상호 작용과 공동 작업을 가능하게 하는 3차원 그래픽 기반의 가상 현실 시스템 모듈의 설계에 관하여 제안하였다. 본 논문에서 제안하는 시스템은 3차원 가상 공간을 기반으로 하여 네트워크를 통한 다중 사용자의 참여와 참여자간의 인터렉션을 가능하게 하는 기반 시스템이라고 할 수 있다. 본 시스템은 클라이언트-서버 모델을 기본으로 하여 구성되었으며, 인증/보안, 분산 처리, 데이터베이스, 객체와 지역관리, 전송 데이터 압축, 동적인 Scene Graph 구성 등 여러 가지 세부 모듈이 복합적으로 사용되었다. 개발된 시스템은 3차원 가상 공간상에서 자신의 아바타를 자유롭게 조작, 네비게이션할 수 있으며, 다른 사용자들의 움직임을 실시간으로 관찰할 수 있다. 향후, 시스템에 여러 가지 모듈을 추가하여 확장하게 되면 교육, 다중 사용자들의 공동 작업, 게임, 3차원 기반의 커뮤니티 형성 등 다양한 분야에 응용될 수 있을 것이다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.160-165
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• 2007

무선 센서 망에서 다중싱크 이동성에 관련된 연구는 단순히 독립된 단일싱크 이동성 확장에 기인한다. 하지만, 다중 싱크의 경우 싱크 상호간의 이동 결집도에 따라 두 가지 그룹으로 분류될 수 있다: 싱크간의 산재된 싱크그룹(loosely coupled sink group)과 밀집된 싱크그룹(tightly coupled sink group)이다. 전자는 기존 다중싱크 연구에서 가정하고 있는 일반적인 모델이다. 반면, 후자의 예로는 전쟁터에서 동일한 작전을 수행하는 작은 분대 단위의 군인들의 이동성 등이 있다. 본 논문은 밀집된 싱크그룹 이동성을 갖는 다중 싱크를 위한 데이터전달 프로토콜을 제안한다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1355-1360
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• 2011

The interaction between the cell and the substrate is the most prominent feature affecting the migration of a crawling cell. This paper proposes a three-dimensional dynamic model using the diffuse interface description that reveals the effects of the interaction between a single crawling cell and the substrate during chemotactic migration. To illustrate the effects of interaction between the cell and the substrate, we consider the interfacial energy between the coexistent materials. Multiple mechanisms including the interface energy, chemotaxis effect, and diffusion, are addressed by employing a diffuse interface model.

• The KIPS Transactions:PartB
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• v.10B no.7
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• pp.751-756
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• 2003

Ant Colony Optimization (ACO) is new meta heuristics method to solve hard combinatorial optimization problem. It is a population based approach that uses exploitation of positive feedback as well as greedy search. It was firstly proposed for tackling the well known Traveling Salesman Problem (TSP) . In this paper, we introduce Multi Colony Ant Model that achieve positive interaction and negative interaction through Intensification and Diversification to improve original ACS performance. This algorithm is a method to solve problem through interaction between ACS groups that consist of some agent colonies to solve TSP problem. In this paper, we apply this proposed method to TSP problem and evaluates previous method and comparison for the performance and we wish to certify that qualitative level of problem solution is excellent.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.5
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• pp.3-16
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• 2001

With the development of Internet, it is widely spreaded to a Intranet based on Internet technology. Intranet is a private, unique network to share the information of organization such as incorporate, research institute and university. With the increase of Intranet using, Intranet environment is developing into Extranet environment which is connected many Intranet. Currently such Intranet and Extranet environments, above all, it is important to solve security problems which can appear through use of information between domains. Thus, in this paper, we propose SSO(Single Sign-on System) model with authorization management and single sign-on operation, and we extend it to enable mutual authentication through inter-working based on PKI(Public Key Infrastructure) in Extranet environments.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.377-380
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• 2001

본 논문에서는 실내에서 액티브 카메라를 사용하여 다중 인물의 얼굴의 위치를 검출하고. 추적할 수 있으며 조명과 배경 등의 영향에 강인한 추적 알고리즘을 제시하고자 한다. 알고리즘은 얼굴영역 검출, 추적의 2단계로 구성되며, 빠르고 효율적인 얼굴영역 검출은 추적 알고리즘의 성능향상으로 이어지므로, 이를 위해 독특한 색상영역 분포를 갖는 피부 색상 특징을 이용하였다. 표본영상에서 추출된 피부색상 픽셀들을 바탕으로 YCbCr 색상계를 사용하여 얼굴 색상모델을 구축한 후, Gaussian 함수를 사용하여 입력 영상의 픽셀과 얼굴색상모델과의 유사도를 결정하였다. 최종 얼굴 영역은 추출된 영역에 대한 얼굴의 타원특징, 해부학적 특징을 이용하여 결정된다. 추적은 추출된 얼굴영역과 temporal Gaussian 필터를 적용한 움직임 추정을 통한 움직임 검출의 조합으로 이루어진다. 또한, 예측버퍼의 사용으로 탐색영역의 축소로 인한 계산량 감소와 처리 속도의 증가시켰으며, pan/tilt가 가능한 카메라를 사용하여 상호 피드백이 가능하도록 하였다. 제시된 알고리즘은 PC 상에서 시뮬레이션되었으며, 좋은 결과를 얻을 수 있었다.