• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.119.4-119
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• 2001

It is the advantage of PLC that digitalization and networking of existing facility can be organized at low price because there is no need further construction of communication line considering that home appliance, information device and various kind of control devices are digitalized at low price. Moreover, AMR(Automatic Meter Reading) is very attractive to utility company because not only does it reduce the cost of reading meter, but also it can control and monitor the demand for energy. So, it can solve the consumers problem best and easily. It also can be easily realized that the utilities can expand there areas to values-added service through existing network. The performance of the PLC modem which is being developed now is not moven enough and much more test for outdoor modem is needed especially. Therefore, we, KEPRI, concentrate our efforts on configuring AMR system for test and investigation of the actual performance of various kinds ...

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1082-1085
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• 2002

By improving Ec/Io of pilot channel in CDMA mobile communication, the transmitting quality of mobile phone may be improved, channel capacity may be increased, and further investment and operation cost may be reduced to build a network. In this paper suggested new cell pattern decision method for base station as one of ways to improve Ec/Io of pilot channel and verified its utility through simulation and field application data.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.433-436
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• 2008

A demand on the spatial data management has been rapidly increased with the introduction and diffusion process of ITS, Telematics, and Wireless Sensor Network, and many different people use the digital map that offers various thematic spatial data. Spatial data for digital map can manage to tile-based and feature-based data. The existing tile-based digital map management systems have difficult problems of data construction, history management, and updating based on a spatial object. In order to solve these problems, this paper proposed the data model for the feature-based digital map management system that is designed for feature-based seamless map, history management, real-time updating of spatial data, and analyzed the validity and utility of the proposed model.

• Proceedings of the IEEK Conference
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• 2003.11b
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• pp.179-182
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• 2003

In this paper, we developed those OpenLS(Open Location Service) Core Services based on the Web-Service, because Web-Service environments provide a suitable method to gather requested information in an appropriate way. The proposed architecture cooperate with OpenLS Core Services( Directory Service, Location Utility Service and Router Determination service) and is an interoperability one - it identifies those global elements of the global Web-Services network that are required in order to ensure interoperability between Web-services. In this paper, a new architecture of OpenLS Core Services is proposed and tested in OpenLS Core Services environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.487-492
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• 2005

As the portable medical equipments consume the power and transmission of the information, they need the system to use long. Although the current wireless transform systems for medical equipments use Bluetooth protocol system, an electricity consumption is big because it uses long and there is the difficulty in the utility We designed a module using the Zigbee protocol which an electricity consumption is more small though a transmission speed is slower than Bluetooth and drew the plan the wireless transmit system for medical equipments to use long.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.352-354
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• 2002

The sag is phenomenon that magnitude of load voltage temporarily decreases because of power system fault. If a certain equipment in industrial process have any trouble result from sag. it can cause utility to be charged for enormous economics loss. Therefore it need to analyze the characteristic of sag and then mitigation method for sags in distribution system in odor to increase reliability. This paper gives an overview of sags characteristic due to short circuit fault in distribution system and after a general discussion of the various forms mitigation, gives a sags mitigation method with concentrating on changing the distribution system like spot network, on-site generation.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.216-218
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• 2002

This study is the modeling of resistive type SFCLs. There was numerical modeling and simulation using EMTP in the conventional modeling of SFCL. The numerical modeling was presented an analysis of numerical characteristic of SFCL. And the modeling using EMTP was made up of the study for setting method of specific parameters of a SFCL. This paper proposes the model of resistive type superconducting fault current limiter using EMTDC(Electromagnetic transients for DC analysis program). The simulation schemes that can be applied to the utility network readily and cheaply under various conditions considering the sort of fault, the capacity of systems as well are strongly expected and emphasized among researchers.

• Korean Management Science Review
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• v.26 no.1
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• pp.21-35
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• 2009

There is a controversy on Internet pricing, flat-rate vs. usage-based. This study gives a comparative analysis between flat-rate and two-part tariff which is realistic alternative of usage-based pricing. In a basic economic model, two-part tariff based on ISP's cost structure satisfies allocative efficiency and relatively expand the number of subscribers. But the characteristics of Internet service like consumers' uncertainty on cost, measurement cost of traffic and network externality induce increase of cost or decrease of marginal utility. The analysis shows that small impact of these can make flat-rate more efficient.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.2
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• pp.559-573
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• 2016

In this paper, we investigate the problem of achieving proportional fairness in hierarchical wireless sensor networks. Combining clustering formulation and scheduling, we maximize total bandwidth utility for proportional fairness while controlling the power consumption to a minimum value. This problem is decomposed into two sub-problems and solved in two stages, which are Clustering Formulation Stage and Scheduling Stage, respectively. The above algorithm, called CSPF_PC, runs in a network formulation sequence. In the Clustering Formulation Stage, we let the sensor nodes join to the cluster head nodes by adjusting transmit power in a greedy strategy; in the Scheduling Stage, the proportional fairness is achieved by scheduling the time-slot resource. Simulation results verify the superior performance of our algorithm over the compared algorithms on fairness index.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.114-119
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• 2010

최근 설계, 시공되는 건축물은 초고층 또는 대단지 주거시설로서 화재발생시 초기에 빠른 대응이 요구 되나 근무자의 첨단 소방시설관리에 대한 지식은 부족한 실정이다. 본 연구에서는 건축물의 대형화로 인한 네트워크제어방식의 효용성을 알아보고 기시공된 현장의 화재수신기 네트워크 운영 실태 및 현황을 파악 하여 관리에 일조하고자 한다. 이를 위해 10개 대형현장의 네트워크를 조사한 결과 경보시스템에 대한 낮은 신뢰도 때문에 타설비와의 시트템구축을 기피하고 있었다. 또한 방재관련 법규의 제한된 규정으로 인한 통신선 사용에 있어서의 문제점도 개선될 필요가 있었다. 아울러 관리자의 잦은 이직으로 인한 기술적 축적 방안 마련, 복지문제와 면적이 넓은 네트워크시스템에 대한 신호처리방법 및 반응시간등에 대한 규정제정이나 운영상 표준화가 필요하였다.