• Journal of information and communication convergence engineering
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• 제17권4호
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• pp.246-254
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• 2019

This paper proposes a solution to the problem of finding a subgraph for a given instance of many terminals on a Euclidean plane. The subgraph is a tree, whose nodes represent the chosen terminals from the problem instance, and whose edges are line segments that connect two corresponding terminals. The tree is required to have the maximum number of nodes while the length is limited and is not sufficient to interconnect all the given terminals. The problem is shown to be NP-hard, and therefore a genetic algorithm is designed as an efficient practical approach. The method is suitable to various probable applications in layout optimization in areas such as communication network construction, industrial construction, and a variety of machine and electronics design problems. The proposed heuristic can be used as a general-purpose practical solver to reduce industrial costs by determining feasible interconnections among many types of components over different types of physical planes.

• Journal of information and communication convergence engineering
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• 제20권3호
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• pp.160-165
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• 2022

This paper proposes an efficient method of reconstructing interconnections when the terminals of each plane change in real-time situations where randomly divided planes are interconnected. To connect all terminals when the terminals of each plane are changed, we usually reconstruct the interconnections between all terminals. This ensures a minimum connection length, but it takes considerable time to reconstruct the interconnection for the entire terminal. This paper proposes a solution to obtain an optimal tree close to the minimum spanning tree (MST) in a short time. The construction of interconnections has been used in various design-related areas, from networks to architecture. One of these areas is an ad hoc network that only consists of mobile hosts and communicates with each other without a fixed wired network. Each host of an ad hoc network may appear or disappear frequently. Therefore, the heuristic proposed in this paper may expect various cost savings through faster interconnection reconstruction using the given information in situations where the connection target is changing.

• Journal of information and communication convergence engineering
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• 제20권2호
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• pp.90-95
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• 2022

This paper proposes a method to find a tree with the maximum number of terminals that can be connected by a given length when numerous terminals distributed in a cluster form are given to the Euclidean plane R2 with several constraints. First constraint is that a given terminal is distributed in a cluster form, second is that a given length cannot connect all terminals in the tree, and third is that there is no curved connection between each terminal. This paper proposes a method to establish more efficient interconnections within terminals distributed in a cluster form by improving a randomly distributed memetic genetic algorithm. The construction of interconnections has been extensively used in design-related fields, from networking to architecture. Additionally, in real life, the construction of interconnections is mostly distributed in the form of clusters. Therefore, the heuristic algorithm proposed in this paper can be effectively utilized in real life and is expected to provide various cost savings.

• International Journal of Internet, Broadcasting and Communication
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• 제7권1호
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• pp.1-5
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• 2015

In this study, we consider the transportation problem in port container terminals. It aims to determine positions in yards to place the containers at the adequate times. The containers on ship must be unloaded one by one from top to bottom, and placed in the main yard in order to reduce additional cost required for unnecessary unloading when getting out by customer with given timetable. The cost for transportation at container terminals could be reduced by a new approach in scheduling: move the containers from ship and stack them onto main yard that minimizes cost of yard crane operation when unloading for customer.

• 한국시뮬레이션학회논문지
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• 제5권1호
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• pp.53-66
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• 1996

Container handling facilities in Korean ports have increased rapidly according to Korean industrialization and the worldwide containerization. Over 98% of total containers handles in Korean ports are handled in Puan ports. This paper presents the estimation method of annual container handling capacity of container terminals by the computer simulation models. Simulation models are developed utilizing SIMAN IV simulation package. Annual handling capacity of real container terminals such as BCTOC and PECT was estimated by the proposed simulation models. Also, Annual handling capaicty of planned or expected terminals in Puan port was estimated. The comparisons between container forecast demand and estimated handling capacity of Pusan port from 1996 through 2001 were made. It showed that Pusan port will have over two million TEU handling capacity shortage during that period and will face enormous port congestion. Lastly, mid term and long-term capacity expansion plansof container terminals in korean ports were discussed.

• 한국컴퓨터정보학회논문지
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• 제17권3호
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• pp.85-93
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• 2012

본 논문에서는 MF-TDMA (Multi Frequency-Time Division Multiple Access) DAMA (Demand-Assigned Multiple Access) 방식을 사용하는 위성 망에서 지상 단말이 네트워크 제어기에게 자원을 요청할 때, 자신에게 유입되어지는 트래픽에 대한 이전 정보(History) 즉, 트래픽 발생 패턴이나 트래픽 종류 등을 바탕으로 자원을 요청하고, 네트워크 제어기는 지상 단말들이 이전에 요청했던 정보(History)를 바탕으로 보다 효율적으로 위성 자원을 할당하여 위성 망 자원 할당 시간의 지연으로 인한 다량의 데이터 폐기를 최대한 억제하기 위한 MF-TDMA DAMA 방식 위성 시스템을 설계하였다. 미군의 전략적 군사 정보망 (Warfighter Information Network-Tactical, WIN-T) 커뮤니티에서는 L-3 Linkabit 다중 주파수-시간 분할 다중 접속 (MF-TDMA) 요청에 의해 할당되어지는 다중 접속 (DAMA) 네트워크 중심 파형 (Network Centric Waveform, NCW)을 full-mesh IP over SHF 위성 통신을 위한 네트워크 표준으로 선택하였다. MF-TDMA 위성 망에서는 네트워크 제어기(Network Controller, NC)가 최대 255개의 지상 단말들 (Earth Terminals, ETs)의 주기적인 자원요청에 대하여 동적으로 위성 망 자원을 할당하여 단말들 간의 통신을 가능하도록 한다.

• 한국컴퓨터정보학회논문지
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• 제11권1호
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• pp.167-176
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• 2006

본 논문에서는 가족 구성원들이 원하는 다양한 제어 단말을 통하여 위치에 상관없이 댁내의 정보가전을 제어하고 모니터링하기 위한 홈 네트워크 액세스 에이전트를 설계 구현한다. 제안되는 액세스 에이전트는 홈 게이트웨이(또는 홈 서버) 상에서 유무선 네트워크를 통합하고, 웹, PDA, 휴대폰 등과 같은 다양한 제어 단말을 사용하여 일관된 메시지 형식으로 홈 네트워크에 접근이 가능하도록 설계한다. 또한 액세스 에이전트의 동작 및 유용성 검증을 위해 다양한 제어 단말의 사용자 인터페이스를 설계하고, 이를 사용하여 접근 제어되는 홈 네트워크 테스트베드를 구현한다.

• 대한전자공학회논문지TC
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• 제44권1호
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• pp.106-112
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• 2007

본 논문에서는 다중-홉(multi-hop) 무선통신시스템에서 보조 및 관리단말을 추가로 갖는 시공간 협동 다이버시티 중계 시스템을 제안한다. 한 협동그룹에 1개 이상의 중계단말을 추가하여, 프레임 에러여부 및 채널정보 등의 상태정보만을 공유한다. 상태가 좋은 수신신호를 가지는 단말을 선택하며, 선택된 각 중계단말은 같은 시공간 부호로 다중안테나 송신다이버시티 중계전송을 한다. 그리고 협동그룹 내에 중계단말 간의 교신 프로토콜을 제안한다. 이 방식에 대해, 수신신호 대 송신신호 비($E_r/E_s$)를 측정하여 성능개선 됨을 증명하였으며, 플랫 페이딩(flat-fading) 채널에서의 시뮬레이션은 기존의 협동다이버시티에 비해 혁신적인 성능향상을 보인다.

• Journal of Multimedia Information System
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• 제2권1호
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• pp.153-162
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• 2015

In today's pervasive computing environments, multimedia content should be adapted to meet various conditions of network connections, terminals, and user characteristics. Scalable Video Coding (SVC) is a key solution for video communication over heterogeneous networks, where user terminals have different capabilities. This paper presents a standard-compliant approach that adapts an SVC bitstream to support multiple users. The adaptation problem is formulated as an optimization problem, focusing on the tradeoff between qualities of different spatial layers of an SVC video. Then the adaptation process is represented by standard metadata of MPEG-21, which can be solved by universal processing to enable interoperable and automatic operation. Our approach provides the users with optimal quality, a wide flexibility, and seamless adaptation. To the best of our knowledge, this is the first study that shows the adaptation tradeoff between spatial layers of a conforming SVC bitstream.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1997년도 Proceedings International Workshop on New Video Media Technology
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• pp.75-81
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• 1997

A new DTPP (Desk-Top Program Production) system has been developed that enables multiple program producers (directors) working at different locations to collaborate over a computer network and prepare a single program for broadcasting. In this system, information is shared among users by exchanging data edited on non-linear editing terminals in program post-production work over a network in real time. In short, the new DTPP system provides a collaborative work space for producing TV programs. The system does not make use of a special server for collaborative work but rather multiple interconnected editing terminals having the same functions. In this configuration, data at a terminal which has just been edited by some operation is forwarded to all other connected terminals for updating. This form of information sharing, however, requires that some sort of data synchronizing method be established since multiple terminals are operating on the same data simultaneously. We therefore adopt a method whereby the system synchronizes the clocks on each terminal at the time of connection and sends an operation time stamp together with edited data. This enables most recently modified data to be identified and all information on all terminals to be updated appropriately. This paper provides an overview of this new collaborative DTPP system and describes the techniques for exchanging edited data and synchronizing data.