• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.1
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• pp.63-74
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• 2005

The telematics device, which is a typical embedded system on the transportation or vehicle, requires the embedded spatial DBMS based on RTOS (Real Time Operating System) for processing the huge spatial data in real time. This spatial DBMS can be developed very easily by SQL3 functions of the ORDBMS such as UDT (user-defined type) and UDF (user-defined function). However, developing index suitable for the embedded spatial DBMS is very difficult. This is due to the fact that there is no built-in SQL3 functions to construct spatial indexes. In this study, we compare and analyze both Generalized Search Tree and Relational Indexing methods which are suggested as common ways of developing User-Defined Indexes nowadays. Two implementations of R-Tree based on each method were done and region query performance test results were evaluated for suggesting a suitable indexing method of an embedded spatial DBMS, especially for telematics devices.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.10
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• pp.1553-1571
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• 1993

A significant amount of research has focused on the development of highly parallel architectures to obtain far more computational power than conventional computer systems. These architectures usually comprise of a large number of processors communicating through an interconnection network. The VLSI (Very Large Scale Integration) and WSI (Wafer Scale Integration) cellular arrays form one important class of those parallel architectures, and consist of a large number of simple processing cells, all on a single chip or wafer, each interconnected only to its neighbors. This paper studies three fundamental issues in these arrays : fault-tolerant reconfiguration. functional reconfiguration, and their integration. The paper examines conventional techniques, and gives an in-depth discussion about fault-tolerant reconfiguration and functional reconfiguration, presenting testing control strategy, configuration control strategy, steps required f4r each reconfiguration, and other relevant topics. The issue of integrating fault tolerant reconfiguration and functional reconfiguration has been addressed only recently. To tackle that problem, the paper identifies the relation between fault tolerant reconfiguration and functional reconfiguration, and discusses appropriate testing and configuration control strategy for integrated reconfiguration on VLSI and WSI cellular arrays.

• Journal of Information Technology Applications and Management
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• v.16 no.4
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• pp.205-222
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• 2009

Considering time-lag in the performance evaluation of information system (IS) investment is important because its effect reveals after certain period of time passed. Particularly it is more in the systems of e-government informatization projects which the amount of investment and the scale of business are huge. Many methods to solve this issue have been proposed such as system dynamics methods, simulations, structural equations etc. However, it is still difficult and unsolved problem because collecting practical data for time-lag analysis is very hard. In this paper, we analyze IS time-lag effect through factor analysis using the accumulated practical operational DB data. For the performance evaluation of the G4C system, the representative e-government web portal, we selected eleven factors reflecting time passing in G4C DB data. With these factors this paper conduct time-lag analysis in four view points. First, we conducted 'Stabilizing of G4C system' and got a result that IS is needed about three years for the stabilization. Second, we conducted 'Utilization of G4C system' and got a result that the utilization reaches appropriate level after in three years later after the introduction of G4C system. Third, we conducted 'Cost reduction effect' and got a result that cost reduction is stable in the third year after the introduction of G4C system. Lastly, we conducted 'System maturity effect' and got a result that the system reaches to the quality level that users expect after third to fourth years. According to the results of this research, we found that performance of IS improv continuously not immediately, and it needs three or four years of time-lag.

• Journal of The Korean Association of Information Education
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• v.10 no.1
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• pp.143-152
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• 2006

The aim of this study was to analyze effects of a blended learning program based on case study approach and to suggest implications in appropriately evaluating blended learning in practices for corporate education and training. In order to achieve the goal, issues such as the ones related to blended learning including development and status quo of blended learning programs in the field of corporate education and training and operation models for the blended learning were reviewed. Then, the outcomes of a blended learning program were completely analyzed through systems approach. The methodology of the study was a mixed research method which was comprised of quantitative and qualitative approaches. The results of quantitative analysis showed that blended learning itself seemed to have significant effects on the leadership capability in general assessment and self assessment. The most viable effects of blended learning in leadership training are said to be actual change of actions and activities in leadership capability of the participants followed by changes in their job tasks contributing to improving the managerial performance of the company, good transfer to current job tasks, and implementation of the practice plans.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.2
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• pp.259-265
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• 2012

Recently, many research works are focusing on DVC (Distributed Video Coding) system for low complexity encoder. Most DVC systems need feedback channel for parity bit control to achieve the good RD performances, however, this causes the system to have high decoding latency and is considered as one of the most critical problems for real implementation. In order to overcome this problem, this paper proposes an effective distributed video decoding method using adaptive LDPCA frame-based parity bit request estimation. The proposed method applies for the pixel-domain Wyner-Ziv system and exploits the statistical characteristics between adjacent LDPCA frames to estimate adaptively the parity bit request. Through computer simulations, it is shown that the proposed method achieves about 80% of latency reduction compared to the conventional no-estimation DVC system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.205-208
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• 2011

In recent years, the user interest has increased for DDS (Data Distribution Service) which is a data centric middleware based on publish-subscribe communication as the demands for real-time data exchange in distributed systems have been growing rapidly. To reflect these needs, many vendors and research groups provide their DDS middleware. However, there has been a problem with interoperability between DDS middlewares because of a lack of common communication rules such as the message exchange and the discovery manner. For this reason, OMG defines RTPS (Real-Time Publish-Subscribe) specification which is the standard network protocol used to exchange data between different implementations of DDS. In this paper, we analyze and design the SDP (Simple Discovery Protocol) of RTPS which enable DDS middleware to provide interoperable discovery mechanism.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.629-631
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• 2015

Recently, the actual demand for electricity usage to out of demand forecasting demand appears to be based on the power of Government to address the insecurity is there are a lot of efforts on a more efficient energy management. In 2011, the first major outage, blackout since the current rate of no more than 10% of our power plants, such as power supply and demand crisis is being repeated. In addition, energy management systems, the demand for care and social areas are being expanded. In this paper, Building power supply and wired/wireless router and to optimize the DDNS (Dynamic Domain Name Service) for remote control and monitoring device for electric consumption Presonal Energy Management System offers a way to implement it. In the future, remote control and access the user's can minimize the settings for additional research is needed.

• Journal of the Korean Data and Information Science Society
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• v.27 no.3
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• pp.711-724
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• 2016

Under variable complex operating environment, various factors can affect the lifetimes of systems. In this research, we study bivariate reliability models having multiple dynamic competing risks. As competing risks, in addition to the natural failure, we consider the increased stress caused by the failure of one component, external shocks, and the level of stress of the working environment at the same time. Considering two reliability models which take into account all of these competing risks, we derive bivariate life distributions. Furthermore, we compare these two models and also compare the distributions of maximum and minimum statistics in the two models.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.4
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• pp.1-7
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• 2009

In this paper, the author presents the MIMO(Multi-Input Multi-Output) receiver algorithm with the capability of inter-cell or inter-sector interference cancellation over multi-antenna OFDM(Orthogonal Frequency Division Multiplexing) systems. As contrast with the previous research dealing with the filtering scheme at the time domain, the proposed algorithm is presented as the pre-filtering scheme which can be applicable to the frequency domain. Note that the proposed one can be implemented only by pilot symbols which are used in the channel estimation. In addition, it is analytically confirmed that the proposed scheme can be applied for either MIMO( C-SM(Collaborative-Spatial Multiplexing)) interference or SIMO(Single-Input Multi-Out) interference. The proposed receiver algorithm is verified by simulations over UL-PUSC SR off in IEEE 802.16e standard. From simulation results, it is confirmed that the proposed one can be applicable regardless of the kind of interference. Furthermore, it is verified that the performance is guaranteed even under Ole severe effect of interference and the improvement of system throughput is guaranteed.

• Spatial Information Research
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• v.20 no.1
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• pp.59-69
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• 2012

For the USN(Ubiquitous Sensor Network) environment which generally uses spatial sensor data as well as aspatial sensor data, a sensor database system to manage these sensor data is essential. In this reason, some sensor database systems such as TinyDB, Cougar are being developed by many researchers. However, since most of them do not support spatial data types and spatial operators to manage spatial sensor data, they have difficulty in processing spatial sensor data. Therefore, this paper developed a spatial sensor database system by extending TinyDB. Especially, the system supports spatial data types and spatial operators to TinyDB in order to manage spatial sensor data efficiently and provides the memory management function and the filtering function to reduce the system overload caused by sensor data streams. Lastly, we compared the processing time, accuracy, and memory usage of the spatial sensor database system with those of TinyDB and proved its superiority through the performance evaluation.