• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.10
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• pp.654-663
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• 2014

Heterogeneous network (HetNet) with the various types of cells, e.g., with the different cell size and transmit power, has been introduced to improve the cell coverage and areal capacity in cellular mobile communication system. In this paper, we consider a practical situation in which all cells share the same wireless resource while some of them have a limited backhaul capacity. More specifically, we formularize a cell association problem that utilizes the minimum wireless resource while satisfying the quality of service (QoS) of all users in terms of their transmission time constraint, and propose a distributed algorithm to find the optimal solution. In the event of bottleneck at the backhaul link in some small cells, the proposed algorithm off-loads some users to the adjacent cell with the less congested backhaul capacity. Finally, we verify that the proposed algorithm supports the more numbers of users to satisfy the specified level of QoS than the conventional user association scheme under the limited access and backhaul capacities.

• Journal of the Economic Geographical Society of Korea
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• v.20 no.4
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• pp.522-535
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• 2017

It is necessary to develop a new location model to support the application of smart technology and confluence in the 4th industrial revolution era. In this study, we propose 'network-type industrial complex' as a method to link several industrial integrated spaces which are dispersed in an area. As a result of conducting a survey of companies in order to develop a new location model, about 89% of companies recognized the necessity of network-type industrial complex. As a condition for activation of the industrial complex, 'complementary function formation', and 'convenience of nodular transportation' were selected. It is expected that it will be possible to supply low-cost, high-efficiency industrial complexes through opening and linking with urban space and infrastructure sharing.

• Journal of the Korea Society of Computer and Information
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• v.10 no.1 s.33
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• pp.125-132
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• 2005

Visual programs consist of user interfaces and process logics. Because most visual IDEs(Integrated Development Environment) are utilized by only one developer, many developers can't cooperate simultaneously in one large-scaled visual Program to promote the development efficiency. This paper suggests a co-development environment for visual programs through which developers can cooperate with each other in the type of distribution. Developers can maintain the coincidence and the confidence of cooperation through a communication window and a job controller to process the Priority of the events that developers make in co-development work. Especially in large-sealed visual Program, the suggested environment reduces the burden that developer takes about the heavy development work, and many developers can divide and take the complex and large program modules according to their ability. We hope that the suggested environment can improve the development productivity and effectivity because it can reduce the time and effort for developing user interfaces in visual programs.

• Journal of the Korea Society of Computer and Information
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• v.15 no.3
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• pp.55-63
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• 2010

On Handoff, existing AP search has chosen one of various APs according to signal strength. However IEEE 802.11 uses Medium Access method with CSMA/CA(Carrier Sensing Multiple Access /Collision Avoidance) that competes to obtain a channel by sharing common medium. For that reason, network performance is heavily affected by the number of nodes and network congestion aside from signal strength. Consequently, in this paper we propose the method that choose one AP which ensures more improved network performance and set up a link, reflecting AP network information in Handoff area, on Handoff in the process of AP selection. We also demonstrate through simulation that it gets maximum performance even in the wireless network which many users concurrently access to, and it has considerable effects on aspects of resources and network management by distribution of users.

• Journal of the Korean Society for information Management
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• v.20 no.2
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• pp.114-133
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• 2003

Recently, the organizations related to cultural contents are gradually expanding access to cultural contents for general public through the distributed network. However, since cultural contents have different characteristics than general contents, the objects, the of cultural contents seldom contain the words generally used for organization and search of information. If the cultural contents system is created without any consideration of such differences. We cannot effectively identify and search resources. Moreover, because the names, expressions and meanings are different between metadata elements of various cultural contents, it is very difficult to interconnect or share information between different systems. In order to solve these problems, proper organization ad management of metadata is vital. In this studym we have comparatively analyzed the data elements of each format based on Dublin Core, EAD, VRA, CDWA, CIMI, and Object ID, the metadata formats approached from various aspects in the cultural contents area. Through this study, we tried to provide the basic materials for integration of cultural contents by securing interoperability of different metadata formats.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.12
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• pp.642-652
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• 2001

Recently, the advent of World-Wide-Web(WWW) and the explosive popularity of the Internet gave birth to collaborative applications which were enabled by computers and networks as their primary media. The progress of 3D computer graphics enabled collaborative application with 3D virtual environments or distributed virtual environments. In this paper, we explain our implementation of the Share collaboration engine which is for collaboration applications based on a distributed virtual environment. We introduce Virtual Architectural Engineering 2000 (VAE2000) that is our pilot application implemented with the Share collaboration engine. The Share collaboration engine proposes a new Share network architecture for management of participants, and it provides some synchronization methods for 3D objects in virtual collaboration. VAE2000 is an experimental application that tries to prevent wastes of human, material and time resources in networked virtual collaboration.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.2
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• pp.19-29
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• 2004

In this paper, the beam steering dipole phased array antenna systems for IMT-2000 base station have been designed. The designed beam steering dipole phased array antenna systems are constituted by the antenna part and the beam steering control system part. The antenna part is designed by the proposed flat dipole for the broadband characteristics, and the 8${\times}$8 dipole way antenna is constructed by the Proposed flat dipole for the directional radiation pattern. Besides the vertical Power divider is designed for the vertical power distribution. The beam steering control system part is designed the horizontal power divider for the horizontal power distribution, the 4-bit phase shifters and the driving circuit of phase shifters for the horizontal beam tilting. In order to evaluate a performance of the designed antenna systems, they were fabricated and the radiation characteristics were measured. From the measured results, we found that the horizontal beams were tilted by the each control signals, and the measured radiation characteristics showed good agreement with the design goals.

• Journal of Korean Society of Archives and Records Management
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• v.20 no.4
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• pp.81-105
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• 2020

This study examines the possibility of applying various recordkeeping methods through a platform built in 2019 by the National Archives of Korea. In particular, it aims to develop a way to track and store transactions using blockchain and to design and present the method of records management automation using smart contracts. In this regard, a literature review, a system analysis of CAMS and MAM, interviews with the experts, designing, implementation, and the development of the system's proof of concept were performed. These efforts resulted in the proposal of an archives and records management strategy utilizing blockchain, which guarantees transparency and accountability by preserving an audit trail on recordkeeping activities.

• Strategy21
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• s.46
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• pp.277-303
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• 2020

2000년 이후 중국 해군은 빠르게 성장하고 있고 이러한 해군의 성장과 더불어 중국은 남중국해 내 도서를 군사기지화 하고 대함 미사일을 개발하고 있다. 이는 제1도련선 내 중국의 해양통제를 위한 노력으로써 인도-태평양 지역 내 미 해군 전력 및 기지에 심각한 위협으로 작용하여 미국의 해양 지배력을 약화시키는데 기여하고 있다. 이를 극복하기 위해서 미국은 인도-태평양 지역내 동맹국과 파트너국들과 함께 시간, 공간, 전력(화력, 군수) 측면에서 작전개념을 발전시켜야 한다. 우선 시간적인 측면에서 중국의 위협에 신속하게 대응하기 위해서 인도-태평양 지역내 국가들의 공중전력(UAVs)과 해상전력(Aegis ships)을 활용하여 대중 정보공유 체계를 강화시켜야 한다. 다음으로 공간적인 측면에서 중국의 위협으로터 인도-태평양 지역 내 미해군의 전력 및 기지를 보호하기 위해서 미 해군 전력을 일본과 호주로 분산 배치시키고 동맹국과 파트너국들의 이지스함, 잠수함 및 무인 수중전력을 적극 활용해야 한다. 전력 측면에서는 해상 기반 화력과 지상 기반 화력을 통합하여 화력의 치명성을 강화해야 하고 인도와의 협력 및 인도-태평양 지역내 함정 손상통제 시설의 확충을 통해서 해상 군수지원 능력을 발전시켜야 한다. 이러한 미 해군의 작전개념 발전 방향이 주는 한국 해군에의 함의는 다음과 같다. 첫째, 미·중간 남중국해 분쟁 발생시 중국의 미사일 위협으로부터 한국 내 위치하고 있는 한·미 해군 전력 보호를 위해 미사일 방어체계(이지스함, 사드 등)를 발전시켜야 한다. 둘째, 대중 감시·정찰 및 미 항공모함단 방호 전력으로 활용 가능한 한국형 원자력 잠수함을 개발해야 한다. 셋째, 미국 뿐만 아니라 인도-태평양 지역내 파트너 국가들을 포함하는 연합훈련을 확대·발전시킴으로써 남중국해내 중국의 해양통제 노력에 대응해야 한다. 넷째, 인명손실을 최소화하고 효율적으로 해군력을 현시할 수 있는 무인 수중·수상체계를 지속적으로 발전시켜 나가야 한다.

• Journal of the Korea Society of Computer and Information
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• v.16 no.7
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• pp.13-23
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• 2011

Grid computing is a new generation computing technology which organizes virtual high-performance computing system by connecting and sharing geographically distributed heterogeneous resources, and performing large-scaled computing operations. In order to maximize the performance of grid computing, job scheduling is essential which allocates jobs to resources effectively. Many studies have been performed which minimize total completion times, etc. However, resource costs are also important, and through the minimization of resource costs, the overall performance of grid computing and economic efficiency will be improved. So in this paper, we propose a multi-objective job scheduling model considering both time and cost. This model derives from the optimal scheduling solution using NSGA-II, which is a multi objective genetic algorithm, and guarantees the effectiveness of the proposed model by executing experiments with those of existing scheduling models such as Min-Min and Max-Min models. Through experiments, we prove that the proposed scheduling model minimizes time and cost more efficiently than existing scheduling models.