• Journal of Communications and Networks
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• v.11 no.2
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• pp.157-165
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• 2009

In this paper, we investigate a dynamic spectrum sharing problem for the centralized uplink cognitive radio networks using orthogonal frequency division multiple access. We formulate a large-scale joint rate and power allocation as an optimization problem under quality of service constraint for secondary users and interference constraint for primary users. We also suggest admission control to nd a feasible solution to the optimization problem. To implement the resource allocation on a large-scale, we introduce a notion of using the conservative factors $\alpha$ and $\beta$ depending on the outage and violation probabilities. Since estimating instantaneous channel gains is costly and requires high complexity, the proposed algorithm pursues a practical and implementation-friendly resource allocation. Simulation results demonstrate that the large-scale joint rate and power allocation incurs a slight loss in system throughput over the instantaneous one, but it achieves lower complexity with less sensitivity to variations in shadowing statistics.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.7B
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• pp.422-430
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• 2007

WDM-PON has been receiving much attention as a key technology to FTTH. As the cost of WDM-PON heavily depends on the number of transceivers implemented at ONU, one of its shortcomings comes from the fixed provision of wavelength resource, which is tightly coupled with costly transceivers. In this paper, we propose a cost-effective WDM-PON architecture for dynamic resource provision. The proposed architecture is based on hierarchical grouping of multiple ONUs into a logical group and hierarchical sharing the resource. For high utilization of dynamic resource, the dynamic resource allocation algorithm is also proposed. We analyze the system efficiency in term of dynamism of system resource and system cost. We also verify that the proposed resource allocation algorithm achieves a high dynamism on resource allocation, and at the same time maintains the fairness between ONUs.

• The Journal of Society for e-Business Studies
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• v.1 no.1
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• pp.227-247
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• 1996

Presented in this paper is a control model for developing virtual factory simulator, which is being operated under the distributed environment. The control model consists of production activity plan and information flows. To incorporate elements of the characteristics of the distributed control system, we suggested a collaboration model. This model is working under the client/server architecture, and also designed for cooperative-distributed shop control(CDSC) system in order to exploit several advantages of client/server architecture. Collaboration among each agent(or client) is done through negotiation and task sharing. Based on a contract net model, the CDSC system has three kinds of agents-order agent, resource agent, and communication forwarding agent. Each agent performs shop scheduling and control through negotiation on contract net. No node in CDSC system can have authority over other node. A bidding scheme is employed far negotiation between order agent and resource agents. The CDSC system can support re-negotiation among resource agents and an algorithm for re-negotiation is also developed. Experimental results are shown to advocate the effectiveness of the CDSC system for CIM environments.

• Knowledge Management Research
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• v.4 no.2
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• pp.35-53
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• 2003

In recent years, knowledge has emerged as a major source of competitive advantage due to the continuous development of information and communication technology, the acceleration of globalization, and the entry into knowledge-based society. Thus interests in knowledge management have been increased significantly. Nevertheless theoretical backgrounds of knowledge management are not actively discussed. Studies on the knowledge management of R&D groups initiating knowledge creation and sharing are not actively conducted either. This study, therfore, provides a research model of knowledge management to investigate relationships among resource and institutional characteristics, knowledge management activities, and knowledge management performance of R&D groups based on knowledge-based theories and institutionalization theories. This study further offers research propositions inherent in the model.

• Journal of Information Management
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• v.34 no.4
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• pp.19-42
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• 2003

Reference services have taken a central place in library and information services. But current digital libraries focus more on access to digital information, and hardly lay emphasis on the service aspects. This paper looks at the current state of research in reference services in digital libraries. It first analyses some representative definitions of digital reference services. It then provides a brief overview of the various online reference and information services currently available on the Web. The paper also reviews the types of the digital reference service in major 'Aska' service sites. Finally, the paper proposes new digital reference service model that specifically bases on the sharing of the human and information.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.3
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• pp.1057-1073
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• 2015

In this paper, we consider cooperative D2D communications in cellular networks. More precisely, a cellular user leases part of its spectrum to facilitate the D2D communication with a goal of improving the energy efficiency of a D2D pair. However the D2D pair is untrusted to the cellular user, such resource sharing may result in the information of this cellular user unsecured. In order to motivate the cellular user's generosity, this D2D pair needs to help the cellular user maintain a target secrecy rate. To address this issue, we formulate a joint spectrum and power allocation problem to maximize the energy efficiency of the D2D communication while guaranteeing the physical layer security of the cellular user. Then, a theorem is proved to indicate the best resource allocation strategy, and accordingly, an algorithm is proposed to find the best solution to this resource allocation problem. Numerical results are finally presented to verify the validity and effectiveness of the proposed algorithm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1311-1317
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• 2010

In this paper, for a uplink space division multiple access system named cooperative spatial multiplexing(CSM), radio resource management(RRM) algorithms are proposed based on sharing uplink channel information among a serving base station(BS) and interfering BSs in a uplink coordinated wireless communication system. A constrained maximum transmit power algorithm is proposed for mobile station(MS) to limit uplink inter-cell interference(ICI). And joint scheduling algorithm among coordinated BSs is proposed to enhance uplink capacity through ICI mitigation by using channel information from interfering BSs. It is shown that the proposed RRM algorithm provides a considerable uplink capacity enhancement by effective ICI mitigation only with moderate complexity.

• Journal of Information Management
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• v.38 no.1
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• pp.75-98
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• 2007

Each domain of web services increased in geometrical progression by remarkable growth of the Internet serves various services or functions, and earns an income. And all services are divided by individual goal in each domain. What counts is that we must offer a personal data, our human resource information to use web service in the majority of cases. Otherwise we have to act under constraint in using the many web services. In this paper, we analyze the database structure or schema for managing human resource information from several web sites or service demands, and propose an agent design and implementation method for preventing duplication input of personal human resource information and sharing the human resource data.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.2
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• pp.35-43
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• 2020

Cloud computing integrates computing resources such as servers, storage, and networks with virtualization technology to provide suitable services according to user needs. Due to the structural characteristics of sharing physical resources based on virtualization technology, threats to availability can occur, so it is essential to respond to availability threats in cloud computing. Existing over-provisioning method is not suitable because it can generate idle resources and cause under-provisioning to degrade or disconnect service. System resources must be allocated in real-time according to the system load to guarantee the cloud system's availability. Through appropriate management measures, it is necessary to reduce the system load and increase the performance of the system. This paper analyzes the work response time according to the allocation or migration of virtual machines and discusses an efficient resource management method considering the system load.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06a
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• pp.352-354
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• 2011

The performance of multihop cognitive radio networks (CRN) can be improved significantly by using multiple channels in spectrum underlay fashion. However, interference due to the sharing of common radio channel and congestion due to the contention among those flows that share the same links become an obstacle to meet this challenge. How to control efficiently congestion and allocate power optimally to obtain a high end-to-end throughput is a key objective in this work. We reexamined the Network Utility Maximum (NUM) problem with a new primary outage constraint and proposed a novel resource allocation strategy to solve it effectively and efficiently.