• Journal of the Korea Society of Computer and Information
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• v.23 no.11
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• pp.9-15
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• 2018

The Ministry of National Defense announced 'Defense Reform 2.0' that aims to strengthen the country's security for decrease of regional uncertainties, growing requirements for advanced technologies, and a need for more efficiency in the Republic of Korea(RoK) Armed Forces this year. It said RoK Armed Forces have to change efficiently in preparation for rapid decline in military service resources as demographic cliff turning into reality, and the rapid evolution of the "battlefield environment" caused by developments in military science and technologies. RoK Navy combat Management System(CMS) made by domestic proprietary technology since 2000s and development centered on Agency for Defense Development require design changes for added requirements. So in this paper, I propose method of design a low cost and high efficiency navy CMS architecture based on high performance server and virtualization technology. And I create a test environment for analysis performance and compare the performance of proposed navy CMS and existing navy CMS.

• Journal of Korea Society of Digital Industry and Information Management
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• v.19 no.3
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• pp.233-244
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• 2023

Although artificial intelligence and machine learning technologies have been used in various fields, problems with personal information protection have arisen based on centralized data collection and processing. Federated learning has been proposed to solve this problem. Federated learning is a process in which clients who own data in a distributed data environment learn a model using their own data and collectively create an artificial intelligence model by centrally collecting learning results. Unlike the centralized method, Federated learning has the advantage of not having to send the client's data to the central server. In this paper, we quantitatively present the performance improvement when federated learning is applied using the building change detection learning data. As a result, it has been confirmed that the performance when federated learning was applied was about 29% higher on average than the performance when it was not applied. As a future work, we plan to propose a method that can effectively reduce the number of federated learning rounds to improve the convergence time of federated learning.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.8
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• pp.927-938
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• 2014

A number of crime and disease relief situation show a clear increasing trend in domestic and overseas country. In particular, we desperately need a fast location information sharing with high accuracy for dealing with this situation efficiently. In this paper, we propose a DGPS framework and performance evaluation based on Web service enable increase location accuracy using low-cost GPS or AGPS. The framework consists of mobile station to realize the final service by receiving the correction values that are created in the base station closest to the current position from DGPS server, base station system to transmit the correct values to DPGS server by installing at base point and DGPS framework working at DGPS server. Our framework is fundamentally designed to respond based on XML to service request. In addition, for performance evaluation, we make use of 3 sites of Level 2 city base-station among the base stations being operated in Suncheon-si. Through performance evaluation, we show that our framework outperforms about 10%~15% in terms of error improvement rate, compared with the existing schemes. And we have the advantage that various services can be expanded owing to receiving the correction values through mobile device such as, smart phone, smart pad, net-book by using XML based Web services.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.935-940
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• 2023

Digital-twin technology is emerging as an innovative solution for all industries, including manufacturing and production lines. Therefore, this paper optimizes all the energy used in a biomass plant based on unused resources. We will then implement a digital-twin prototype for biomass plants and evaluate its performance in order to improve the efficiency of plant operations. The proposed digital-twin prototype applies a standard communication platform between the framework and the gateway and is implemented to enable real-time collaboration. and, define the message sequence between the client server and the gateway. Therefore, an interface is implemented to enable communication with the host server. In order to verify the performance of the proposed prototype, we set up a virtual environment to collect data from the server and perform a data collection evaluation. As a result, it was confirmed that the proposed framework can contribute to energy optimization and improvement of operational efficiency when applied to biomass plants.

• Journal of The Korean Digital Architecture Interior Association
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• v.13 no.4
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• pp.33-39
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• 2013

As lighting energy consumption in buildings occupies high ratio, technical researches to solve it have been constantly carried out. However, basic studies on light environment performance evaluation is actually deficient and only at a level of a simple illumination monitoring. Thus, this study has suggest a light environment energy performance evaluation based on actual residence environments to allow setting lighting interoperation and user required illumination. Conclusions from the study are as follows: 1) As the performance evaluation suggested by this study has not only derived lighting energy usage as well as monitored simple indoor illumination distribution, it is quantitative and allows derivation of visual results. 2) The performance evaluation suggested by this study allows inputs of user required illumination through the performance evaluation server, which is able to support for performance evaluations for various works and users. 3) This study has verified validity of the performance evaluation method by analyzing results of lighting energy reduction by executing performance evaluation on changes of light shelf that is a natural lighting system through the suggested performance evaluation method. This study is significant from a viewpoint that it has suggested a quantitative performance evaluation method on the basis of actual residence environments. Those researches concerned on the energy performance evaluation should be constantly progressed from an aspect that they are another solution of the energy problems.

• Journal of Korea Spatial Information System Society
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• v.1 no.2 s.2
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• pp.137-149
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• 1999

Spatial database systems in client-server environment have network overload due to the large amount of spatial data transmission. Users use the window query that loads partial region of a whole map for quick response time in the environment. A series of window query such as screen movement, enlargement or shrinkage requires data in similar region and this increases network overload by re-transmitting the same data in intersected region with the earlier transmitted region. Removing the transmitted data from query results can solve this problem. In this paper, we design and implement a spatial object manager in order to remove the intersected region occurred by a series of window query. The spatial object manager manages the object identifiers of transmitted objects and removes transmitted objects from spatial objects of the query result by using the removal technique of the intersected region for the transmission and comparison. We utilize GEOMania Millennium server, an open client-server spatial database system, as spatial object manager in this paper. The result of the performance evaluation shows that the spatial object manager removes the transmission of the data redundancy, reduces network overload and improves the overall system performance.

• Journal of Internet Computing and Services
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• v.19 no.1
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• pp.67-76
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• 2018

This paper addresses the problem of efficient processing of region monitoring queries. The centralized methods used for existing region monitoring query processing assumes that the mobile object periodically sends location-updates to the server and the server continues to update the query results. However, a large amount of location updates seriously degrade the system performance. Recently, some distributed methods have been proposed for region monitoring query processing. In the distributed methods, the server allocates to all objects i) a resident domain that is a subspace of the workspace, and ii) a number of nearby query regions. All moving objects send location updates to the server only when they leave the resident domain or cross the boundary of the query region. In order to allocate the resident domain to the moving object along with the nearby query region, we use a query index structure that is constructed by splitting the workspace recursively into equal halves. However, However, the above index structure causes unnecessary division, resulting in deterioration of system performance. In this paper, we propose an adaptive split method to reduce unnecessary splitting. The workspace splitting is dynamically allocated i) considering the spatial relationship between the query region and the resultant subspace, and ii) the distribution of the query region. We proposed an enhanced QR-tree with a new splitting method. Through a set of simulations, we verify the efficiency of the proposed split methods.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.2
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• pp.100-107
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• 2004

The development of a Web-based powertrain performance simulation system is introduced. The development approach of system architecture and each module is introduced along with the H/W and S/W used. The interface with all users is developed via a JAVA Applet. The powertrain modeling and other job history data of a user is managed systematically on the server by database to increase the reusability of the data. A self-developed program using object-oriented programming is used as a solver for the performance simulation. The graph tool for the analysis of simulation results has the collaboration support developed based on JAVA so that synchronous users can view the same result. As a result, the powertrain simulation is possible only with Web-browser for the user and the collaboration support among the relevant engineers is possible.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.2
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• pp.15-25
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• 2017

A System can be more Dependable from some types of Threats if the Dependability Level Against the Threat on the System is Increased. However, The Dependability-performance Tradeoff should be Considered because the Increased Dependability may Degrade the Performance of the System. Therefore, it is Efficient to Temporally Increase the Dependability Level to High only when an Threat is Predicted on the System in a Short time while Maintaining the Level in Low or mid in Normal Situations. In this Paper, we Present a Threat Prevention Strategy for a Networked Node by Dynamically Changing the Dependability Level According to the Threat Situation on its Logically/physically Neighboring Nodes. As case Studies, we Employ our Strategy to an Internet Server Against TCP SYN Flood Attacks and to a Checkpoint and Rollback System Against Transient Faults. Our Performance Analysis Shows that our Strategy can Effectively Relieve the Damage of the Failure without Serious Performance Degradation.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.5
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• pp.55-64
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• 1996

This paper presents performance evaluation of a new high speed inter-processor communication(HIPC) network for large capacity and high performance digitral switching system. The HIPC structure implements the fast reservation and concurrent arbitration technique (modified round-robin arbitration). The performance evaluation of HIPC was performed by not only computer simulation but also numerical approximation method which was derived for a single server multi-queue system with nonexhaustive cyclic service. The approximation results are almost same with that of computer simulation. The TDX-10 basic callscenario was applied to the HIPC netowrk and analyzed. these results were compared with TDX-10 IPC and shows that the difference of th emean waiting time in the TX buffer of NTP node increases sharply according to the increase of the message arrival rate.