• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.6
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• pp.2848-2869
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• 2017

Mobile Wireless Sensor Networks (MWSN) are usually constrained in energy supply, which makes energy efficiency a key factor to extend the network lifetime. The management of the network topology has been widely used as a mechanism to enhance the lifetime of wireless sensor networks (WSN), and this work presents an alternative to this. Software Defined Networking (SDN) is a well-known technology in data center applications that separates the data and control planes during the network management. This paper proposes a solution based on SDN that optimizes the energy use in MWSN. The network intelligence is placed in a controller that can be accessed through different controller gateways within a MWSN. This network intelligence runs a Topology Control (TC) mechanism to build a backbone of coordinator nodes. Therefore, nodes only need to perform forwarding tasks, they reduce message retransmissions and CPU usage. This results in an improvement of the network lifetime. The performance of the proposed solution is evaluated and compared with a distributed approach using the OMNeT++ simulation framework. Results show that the network lifetime increases when 2 or more controller gateways are used.

• Journal of the Korea Computer Industry Society
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• v.3 no.8
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• pp.1049-1062
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• 2002

As the distributed resources in the networks have become increasingly popular, the accesses to these resources having been activated. Especially, the accesses to the distributed resources using the mobile agent technologies provide the mechanisms supporting mobility with mobile users as well as the dynamic accesses to the resources in the fixed networks. Proxy-based mobile agent model is defined as mobile agent network model which allocates the hierarchical domains to the distributed resources changed dynamically, assigns one proxy server for each domain, and promotes the management and the cooperation of the mobile agents. In this paper, we introduce the architecture and the execution scenario for proxy-based mobile agent model which is suitable for the hierarchical management domains. In simulation, we evaluate the proxy server's route optimization functionality and the performance reducing execution time of the mobile agents.

• Journal of Internet Computing and Services
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• v.4 no.1
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• pp.53-65
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• 2003

I/O processing speed of relatively sluggish storage devices incurs overall performance degradation in computer systems. As a solution to improve the situation, SAN(Storage Area Network) has been proposed. In order to utilize a SAN system more effectively, where storage devices are directly connected with a high speed network such as Fibre Channel, a proper management tool is needed. In this paper, we present a design and implementation of a performance monitoring and configuration management tool for the SANtopia system which supports global file sharing in the SAN environment The developed tool is to monitor the performance of the Linux hosts composing the SANtopia system and to manage the configuration of the hosts and storage devices. It also supports GUI(Graphic User Interface) environment using the JAVA programming language.

• The Journal of Society for e-Business Studies
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• v.3 no.1
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• pp.23-41
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• 1998

In a centralized database system, all system components reside at a single platform. In recent years there has been a rapid trend toward the integration of information systems over multiple sites that are interconnected via a communication network, and users' needs are changed to integration of multiple information sites. Multi database System is one of solutions for integrating distributed heterogeneous databases. However the problems in multi database system are restriction in distributed environment support, limitation in integrating heterogeneous media type data, static integration, and data-only of integration. In order to solve these problems, we propose a hybrid database integration model, HyDIM. HyDIM is used for the integrating legacy multimedia data, adopting CORBA, MDS, and mediator. We demonstrate a prototype system far PDM application domain.

• Convergence Security Journal
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• v.4 no.2
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• pp.43-51
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• 2004

Operating systems and application programs have security vulnerabilities derived from the software development process. Recently, incident cases related with the abuses of these vulnerabilities are increasing and the damages caused by them are becoming very important security issues all over the nations. Patch management is one of the most important processes to fix vulnerabilities of softwares and to ensure a security of systems. Since an institute or a company has distributed hierarchical and heterogeneous systems, it is not easy to update patches promptly. In this paper, we propose patch management framework to safely distribute and install the patches on Windows, Linux, and Solaris client systems. Besides, we considered extensibility and hierarchical structure for our patch management framework to support large scaled network environment.

• Journal of Information Processing Systems
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• v.16 no.6
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• pp.1447-1458
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• 2020

This paper describes a structured overlay network scheme based on multiple different time intervals. Many types of data (e.g., sensor data) can be requested at specific time intervals that depend on the user and the system. These queries are referred to as "interval queries." A method for constructing an overlay network that efficiently processes interval queries based on multiple different time intervals is proposed herein. The proposed method assumes a ring topology and assigns nodes to a keyspace based on one-dimensional time information. To reduce the number of forwarded messages for queries, each node constructs shortcut links for each interval that users tend to request. This study confirmed that the proposed method reduces the number of messages needed to process interval queries. The contributions of this study include the clarification of interval queries with specific time intervals; establishment of a structured overlay network scheme based on multiple different time intervals; and experimental verification of the scheme in terms of communication load, delay, and maintenance cost.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.3
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• pp.67-78
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• 2013

In this paper, We proposed an development method of application framework for using the precision time protocol(PTP) based on physical layer devices to synchronize clocks across a network with IEEE1588 capable devices. The algorithm was not designed as a complete solution across all conditions, but is intended to show the feasibility of such a for the PTP(Precision Time Protocol) based on time synchronization of heterogeneous network between devices that support in IEEE 1588 Standard application framework. With synchronization messages per second, the system was able to accurately synchronize across a single heavily loaded switch. we describes a method of synchronization that provides much more accurate synchronization in systems with larger networks. In this paper, using the IEEE 1588 PTP support for object-oriented modeling techniques through the 'application framework development Development(AFDM)' is proposed. The method described attempts to detect minimum delays, or precision packet probe and packet metrics. The method also takes advantage of the Tablet PC(Primary to Secondary) clock control mechanism to separately control clock rate and time corrections, minimizing overshoot or wild swings in the accuracy of the clock. We verifying the performance of PTP Systems through experiments that proposed method.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.1
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• pp.108-117
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• 2007

For a PERT network the sensitivity analyses are valuable tools for effective management and control of a project. In a previous article, a method was developed for the sensitivity analysis of the expected project completion time (${\mu}_{T}$) with respect to the expected duration of an activity (${\mu}_{i}$) under the assumption that the durations of activities are independent and normally distributed. In the present article, a method is presented for the sensitivity analysis of ${\mu}_{T}$ with respect to ${\mu}_{i}$ when the durations of activities are independent and follow discrete distributions, which utilizes the previous sensitivity analysis method with modifications. The accuracy of the proposed method is assessed using various example PERT networks, and the computational results indicate that the accuracy is comparable to that of direct Monte Carlo simulation.

• Korean Management Science Review
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• v.10 no.1
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• pp.107-125
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• 1993

Modern telecommunication switching systems are SPC(Stored Program Control) machines handling voice, data and other kinds of traffic, in an environment which tends to be fully digital switching and transmission. The throughput of such systems is determined by the real time capacity of its centralized or distributed control processors and by the traffic capacity of the switching network. Designers must verify the traffic and call processing capacity of the switching system and check its performance under traffic load before it is put into service. Verification of traffic and call processing capacity of switching systems is one of the problems treated by teletraffic studies ; teletraffic studies are based on stochastic process, queueing theory, simulations and other quantitative methods of decision making. This study suggests the general methodology to evaluate the throughput and performance of the ISDN switching system. TDX-10 ISDN switching system are employed to give illustrative examples of the methodologies discussed in this study.

• Korean Institute of Interior Design Journal
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• v.16 no.4
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• pp.110-118
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• 2007

Technology has been viewed at various stages of civilization as leading to future progress. The building, its services systems and management of the work process all contribute to the well-being of people within an organization. Productivity relies on there being a general sense of high morale and satisfaction with the workplace. Now buildings are considered as providing a milieu for human creativity. Flexibility, adaptability, service integration and high standards of finishes offer an intelligence threshold. Building Automation System(BAS) - controlled lighting systems may offer incremental energy saving. Conventional Lighting control systems often control equipment in a single room or over the limited area, because they are centralized control systems, which means that all the controlled circuits must be wired to a single control panel. The computers used by these systems are typically dedicated microprocess that perform only lighting control functions. By comparison, modern Building automation systems are distributed control system, which means that their computing hardware and software are distributed as a network that microprocessor-based control modules and standard PC. PLC(Programmable Logic controller) is extensible virtually without limits, so that all the lighting in a facility can be controlled by single, unified system - the same system that also can control and monitor the building's HVAC, security, and manufacturing processed, elevators, and more. A Building automation system can control light using schedules, manual controls, occupancy sensors, and photosensors, either singly or in combination. Building Lighting control and monitoring system will be for a energy saving and efficient building management system.