• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.522-523
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• 2013

Delay Tolerant Network (DTN)란 노드 간 통신의 지연 시간이 길고 연결 단절이 자주 일어나는 네트워크 상황에서 데이터를 안정적으로 전달할 수 있도록 지원할 수 있는 네트워크를 말한다. DTN은 노드들 간의 연결 정도의 강약을 파악하여 연결 정도가 높은 노드를 통해 목적 노드로 메시지를 전달하는 방식을 사용한다. 노드들의 움직임이 빠르고 서로간의 거리가 멀어 지속적인 종단 간 연결성이 보장 되지 않는 상황일 때 DTN을 사용하면 안정적인 전송이 가능하다. 이때 이 노드들의 움직임을 예측 할 수 있다면 더 효과적인 메시지 전달이 가능 할 것이다. 이 논문에서는 이동 노드의 속도와 목적지 등과 같은 이동성 정보를 이용해 노드의 위치를 예측하여 효과적인 메시지 전달 경로를 결정하는 이동 예측 기반의 DTN 알고리즘을 제안한다. 이 알고리즘은 Mobility Strategy Sharing Location Service Protocol을 발전시켜 위치 정보 업데이트의 오버헤드를 최소화한다.

• Smart Structures and Systems
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• v.13 no.5
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• pp.775-796
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• 2014

This study presents a vibration-based health monitoring strategy for short span bridges utilizing an inspection vehicle. How to screen the health condition of short span bridges in terms of a drive-by bridge inspection is described. Feasibility of the drive-by bridge inspection is investigated through a scaled laboratory moving vehicle experiment. The feasibility of using an instrumented vehicle to detect the natural frequency and changes in structural damping of a model bridge was observed. Observations also demonstrated the possibility of diagnosis of bridges by comparing patterns of identified bridge dynamic parameters through periodical monitoring. It was confirmed that the moving vehicle method identifies the damage location and severity well.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.45
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• pp.33-45
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• 1998

The typical characteristic of PDM(Product Data Management) System seperates the databases to store the meta data and applications. Therefore, meta data contains the information for the location of file, user profiles, relationships between the files, and process. PDM utilizes these information efficiently and does file management, configuration management, and process management. In this view, the integration strategy of PDM is to merge data and process. In the view of architecture, the interface between data and application and the actions of each application execute seamlessly. This architecture is viewed as integrated data and process among enterprises and implemented with client/server technology in distributed process environment that interfaced with open object-oriented technology which is developed with business object in the object-oriented infrastructure. In this paper, we studied the definition, function, and scope of PDM and researched the core technologies to implement the PDM integration environment. We also researched the PDM utilization in distributed enterprise environment and implementation of PDM integration environment with this technical background.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.4
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• pp.322-329
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• 2005

This paper considers the application of mobile robot to the herding problem. The herding problem involves a ‘pursuer’ trying to herd a moving ‘evader’ to a predefined location. In this paper, two mobile robots act as pursuer and evader in the fenced area, where the pursuer robot uses a fuzzy cooperative decision strategy (FCDS) in the herding algorithm. To herd evader robot to a predefined position, the pursuer robot calculates strategic herding point and then navigates to that point using FCDS. FCDS consists of a two-level hierarchy: low level motion descriptors and a high level coordinator. In order to optimize the FCDS, we use the multi­thread evolutionary programming algorithm. The proposed algorithm is implemented in the real mobile robot system and its performance is demonstrated using experimental results.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.3
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• pp.220-225
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• 1999

This paper presents an UPFC (Unified Power Flow Controller) model for stability study using PSS/E. The proposed UPEC model was implemented by IPLAN which is a high level language. As a control strategy for damping electromechanical oscillations, energy function method was adopted. By the adopted control law, the damping effect is robust with respect to loading condition, fault location and network structure. Furthermore, the control imputs are based on local signals. The effect of control of the UPFC model was demonstrated on an one machine infinite bus system and a two area system.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.157-159
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• 2001

최근 이동 단말 사용자의 수가 급증함에 따라 네트워크 트래픽을 줄여 신속한 호 설정을 가능하게 하는 것이 중요하게 되었다. 이러한 목적을 달성하기 위하여, 빈번하게 호 요청을 하는 이동 단말들에 대해서는 캐쉬를 사용하는 기법이 제안되었다. 그러나, 기존의 캐쉬 기법은 낮은 캐쉬 실패와, 캐쉬 실패 발생시 불필요한 네트워크 지연을 초래하는 문제점이 있다. 본 논문에서는 이동 단말 사용자들이 이동 지역성을 가진다는 점을 이용하여 캐쉬 실패가 발생하더라도 HLR까지 질의하지 않고 포워딩 포인터를 따라 인접 VLR들을 질의하게 함으로써 시스템 전반적으로 위치 질의 비용을 줄여 신속한 호 설정을 가능하게 한다. 이는 HLR로 집중되는 네트워크 트래픽을 감소시켜 PCS 네트워크 사용자들에게 보다 나은 QoS를 제공하는데 이용될 수 있다. 아울러 제안하는 기법이 기존의 위치 관리 기법들보다 위치 관리비용 측면에서 보다 효율적임을 수학적 성능 분석 모델을 통하여 보인다.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.123-126
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• 2008

This research develops a methodology for standard design of spatial Database utilizing the disaster ethnography. Especially, the disaster response operation is sensitive to the size of the disaster, location, damage situation, resource a variability, etc. Moreover, there are many unknown and unexpected factors that will affect the disaster response strategy. But, the future Crisis Management Systems is needed that past disaster teaching. In another words, from now on the response systems need to prepare several scenarios and spatial data and manual etc. before the disaster. Then, this research is the experimental research which examined the relationship between the disaster-ethnography and the GIS spatial data of disaster.

• Journal of information and communication convergence engineering
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• v.11 no.1
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• pp.24-29
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• 2013

In this paper, we propose a fuzzy inference model for a navigation algorithm for a mobile robot that intelligently searches goal location in unknown dynamic environments. Our model uses sensor fusion based on situational commands using an ultrasonic sensor. Instead of using the "physical sensor fusion" method, which generates the trajectory of a robot based upon the environment model and sensory data, a "command fusion" method is used to govern the robot motions. The navigation strategy is based on a combination of fuzzy rules tuned for both goal-approach and obstacle-avoidance based on a hierarchical behavior-based control architecture. To identify the environments, a command fusion technique is introduced where the sensory data of the ultrasonic sensors and a vision sensor are fused into the identification process. The result of experiment has shown that highlights interesting aspects of the goal seeking, obstacle avoiding, decision making process that arise from navigation interaction.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.536-541
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• 2002

This paper proposes an approach of automatically calculating the center location of fiducial marks up to sub-pixel accuracy with model-free condition. The conceptual model, composed of two assumptions, about general geometric property of fiducial area and fiducial mark is established. The proposed approach is primarily based on the strategy of calculating the center of symmetry and is composed of three steps of processing: (a) determining horizontal center of fiducial area, (b) locating center of a fiducial mark, and, (c) finally calculating the exact center up to sub-pixel accuracy. Evaluation with respect to RMK style marks and RC style ones shows that the proposed approach can be evaluated as robust one. However there are several images which can't be analyzed by the proposed approach.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.269-272
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• 1998

This paper presents an UPFC(Unified Power Flow Controlled model that considered rating for stability study. The proposed UPFC model was implemented by PSS/E and IPLAN. As a control strategy for damping electromechnical oscillations, energy function method was adopted. By the adopted control law, the damping effect is robust with respect to loading condition, fault location and network structure. The effect of control of the UPFC model was demonstrated on a one machine infinite bus system.