• Journal of Communications and Networks
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• v.16 no.2
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• pp.140-145
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• 2014

In this paper, we propose an anti-interference cooperative spectrum sharing strategy for cognitive system, in which a secondary system can operate on the same spectrum of a primary system. Specifically, the primary system leases a fraction of its transmission time to the secondary system in exchange for cooperation to achieve the target rate. To gain access to the spectrum of the primary system, the secondary system needs to allocate a fraction of bandwidth to help forward the primary signal. As a reward, the secondary system can use the remaining bandwidth to transmit its own signal. The secondary system uses different bandwidth to transmit the primary and its own signal. Thus, there will be no interference felt at primary and secondary systems. We study the joint optimization of time and bandwidth allocation such that the transmission rate of the secondary system is maximized, while guaranteeing the primary system, as a higher priority, to achieve its target transmission rate. Numerical results show that the secondary system can gain significant improvement with the proposed strategy.

• Proceedings of the Korea Database Society Conference
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• 2010.06a
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• pp.65-74
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• 2010

Most university has provided the information system that fit with their university peculiarity only, but there is not proper evaluation on the user satisfaction by that. In this study, first of all, it analysed which factors give satisfaction to the users when university operated the information systems and inquired the needed outcome variables in order to operate successful university information system. Through the inquisition of fitting supposition, we got something that organizational support and computer self efficacy which is personal factors were effected as an affirmative side to make a user satisfactions of information system. In more detail, organizational support and personal factors effected as an affirmative side to the quality of information system. And, so the quality of information system was influenced to user satisfaction that it raised the work result and increased the work products in organization through personal outcomes.

• Journal of Positioning, Navigation, and Timing
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• v.9 no.4
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• pp.387-395
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• 2020

Accuracy of an integrated Global Positioning System (GPS) / Inertial Navigation System (INS) relies heavily on the visibility of GPS satellites. Especially, its accuracy is dramatically degraded in urban canyon due to signal obstructions due to large structures. In this paper, we propose a new integrated positioning system that effectively combines INS, GPS, ultrasonic sensor, and barometer in GPS-denied environments. In the proposed system, the ultrasonic sensor provides velocity information along the forward direction of moving vehicle. The barometer output provides height information compensated for the pressure variation due to fast vehicle movements. To evaluate the performance of the proposed system, an experiment was carried out by mounting the proposed system on a test car. By the experiment result, it was confirmed that the proposed system bears good potential to maintain positioning accuracy in harsh urban environments.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.5
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• pp.608-614
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• 2014

Recent developments and trends in the electric power consumption clearly indicate an increasing use of DC in end-user equipment. According to the trends, new DC power distribution systems have been researched and developed although we presently enjoy a predominantly AC power distribution system. We can use various grounding schemes in DC distribution system as well as in AC distribution system to protect human body and equipments. However, we need to evaluate carefully which grounding scheme is appropriate for a specific system before applying those schemes. In this paper, we analyze the human safety and system effect according to various grounding schemes in Low Voltage DC (LVDC) distribution system. Some components in LVDC distribution system are modeled and computer simulations are conducted by using ElectroMagnetic Transient Program (EMTP).

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.243-251
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• 2000

In general, Rough Set theory is used for classification, inference, and decision analysis of incomplete data by using approximation space concepts in information system. Information system can include quantitative attribute values which have interval characteristics, or incomplete data such as multiple or unknown(missing) data. These incomplete data cause the inconsistency in information system and decrease the classification ability in system using Rough Sets. In this paper, we present various types of incomplete data which may occur in information system and propose INcomplete information Processing System(INiPS) which converts incomplete information system into complete information system in using Rough Sets.

• Journal of the Korea Society of Computer and Information
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• v.20 no.8
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• pp.35-43
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• 2015

Recently, internal information leaks is increasing rapidly by internal employees and authorized outsourcing personnel. In this paper, we propose a method to integrate internal control systems like system access control system and Digital Rights Managements and so on through expansion model of SIEM(Security Information Event Management system). this model performs a analysis step of security event link type and validation process. It develops unit scenarios to react illegal acts for personal information processing system and acts to bypass the internal security system through 5W1H view. It has a feature that derives systematic integration scenarios by integrating unit scenarios. we integrated internal control systems like access control system and Digital Rights Managements and so on through expansion model of Security Information Event Management system to defend leakage of internal information and customer information. We compared existing defense system with the case of the expansion model construction. It shows that expanding SIEM was more effectively.

• Korean Journal of Remote Sensing
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• v.37 no.1
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• pp.153-160
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• 2021

Land Surface Temperature (LST) is the radiological surface temperature which observed by satellite. It is very important factor to estimate condition of the Earth such as Global warming and Heat island. For these reasons, many countries operate their own satellite to observe the Earth condition. South Korea has many landcovers such as forest, crop land, urban. Therefore, if we want to retrieve accurate LST, we would use high-resolution satellite data. In this study, we made LSTs with 4 LST retrieval algorithms which are used widely with Landsat-8 data which has 30 m spatial resolution. We retrieved LST using equations of Price, Becker et al. Prata, Coll et al. and they showed very similar spatial distribution. We validated 4 LSTs with Moderate resolution Imaging Spectroradiometer (MODIS) LST data to find the most suitable algorithm. As a result, every LST shows 2.160 ~ 3.387 K of RMSE. And LST by Prata algorithm show the lowest RMSE than others. With this validation result, we choose LST by Prata algorithm as the most suitable LST to South Korea.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.11-12
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• 2006

An algorithm to improve the efficiency of the hierarchical routing in ZigBee Networks is proposed. By forwarding the data to the nearest neighbor in the hierarchy, more efficient path can be achieved without any control and memory overhead. Simulation results shows the proposed algorithm provides about 20% shorter path.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.169-175
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• 2001

It is not easy for business workers to find proper information for his job, because of the following problems:(1) information exist in various information system both internal and external with diverse formats(2) he cannot estimate relevance of all the information and (3) he cannot select proper information among large volume of information. The requirements for the systems are the following things:(1) search of relevant information from various internal and external information systems(2) proving an integrated view of information for workers, and (3) information processing and decision-making are seamlessly integrated fro business workers. We proposed an agent system to fulfill the requirements. We focus on the purchasing job, and developed a prototype system. PIPA(Purchasing Information Process Agent). The PIPA performs not only information processing jobs(information search gathering, display, business form -making)but also decision-making support job (evaluation of supplier candidates, and apply of sourcing policy) for sourcing manager. The framework of the PIPA can be appled to other information processing and desision-making jobs.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.8 no.4
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• pp.260-263
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• 2008

In this paper we propose Personal Information Management System for Library Database. It manages personal search pattern for the given user and provide specific book list for library book search system. With the proposed system, the conventional overlap searching time will be decreased with personalized information and search history. This system manages the individual data according to personal searching pattern, sequence and usability. Therefore, the user can locate necessary book information more accurately with their distinct interest and search history.