• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.61-64
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• 1996

Currently many researches are going on a Picture Archiving and Communication System (PACS) which can handle a large number of image data very efficiently. However, the price of those systems are very expensive to a small and medium hospital. In this paper, we developed a PC based Mini-PACS at a low price with a high performance. The main components of the designed system are: Image processing and display for a diagnosis, Client/Server database management system, Multi-monitor display system, Connection through the World Wide Web with Common Gateway Interface.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.5 s.23
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• pp.29-43
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• 2002

Accesses to lands, houses, the Internet and other utilities are regarded as basic human needs to escape poverty and are required to recognize the relationships between the digital divide and socio-economical inequality. The digital divide might not be a single technical disparity, but stems from a complicated mixture of economic and socio-technical symptoms of inequality. There is growing awareness of scrutinizing causal mechanisms between the digital divide and poverty since combating poverty could be a primary step to mitigate the digital divide. In this paper, the Hexad model is proposed to explicate poverty interpretation by using 6 parameters as a major tool for partly assisting in poverty monitoring system in connection with land information. A solution model of the Internet is suggested to break the digital divide. It expounds a conceptual framework and new idea for poverty management to notify spatio-temporal locations of poor actors and geography of the digital divide when efforts of poverty eradication hinge on understandings of geographic location of digital disadvantaged groups through parcel-based land information.

• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.293-298
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• 2001

This paper propose the DoubleQ web server that classifies incoming requests according to whether the requested document is cached or not. Requests that demand a cached document is put into the Service Queue while other requests are added to the Defer Queue. The DoubleQ web server services requests that are in the Service Queue before it services requests in the Defer Queue. This strategy is used to reduce disk accesses that have been the predominant overhead of traditional web servers. Experimental results using synthetic data show that improvements in the average user response time and the throughput of the web server may be achieved.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.1
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• pp.41-49
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• 2012

This paper describes the operation mode development for the grid-tied PMSG(permanent magnet synchronous generator) wind power system combined with a battery energy storage. The development of operation modes was carried out through simulations with PSCAD/EMTDC software and experiments with a 10kW hardware prototype. The detailed simulation models for PMSG wind power system and battery energy storage were developed using user-defined models programed with C-code. A 10kW hardware simulator was built and tested in connection with the local load and the utility power. The simulation and experimental results confirm that the grid-tied PMSG wind power system combined with battery energy storage can supply highly reliable power to the local load in various operation modes.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.258-260
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• 2004

This paper analyse a operating characteristics when the Community Energy System (CES) is operated islanding mode. In the near future, CES might be one of major energy supply structures. The basic concept of CES is that it supplies electrical and thermal energy to the local customer loads through the islanded power network separated from the grid. The CES must be supplying local load with stable energy on the islanding mode, analysing necessary to thoroughly the operation feature. In order to show them, in this paper, we model the CES with 2.34 MVA DG and simulate the operating feature on the islanding mode of CES. The simulation results show that, in order to stability operate, the CES need the efficient load management and generation control schemes during the transition periods.

• Journal of Korea Multimedia Society
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• v.12 no.12
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• pp.1796-1808
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• 2009

Elementary school students have a little awareness of privacy protection since they do not have many opportunities for systematic education on information and communication ethics. Hence, they are likely to expose their own information to others and sometimes bring on a lot of misuses by using others' information. In this paper, we provide an idea for teaching and learning methods which the elementary school students acquire privacy protection and management methods and raise their practical capabilities. We develop a role play teaching and learning model in connection with various Information and Communication Technology (ICT) activities and establish the instruction plans. Moreover, we apply them to the actual classes at grade five and six of the elementary school students respectively, and finally analyze the results. The proposed teaching and learning method shows that the students participated in a series of learning activities have higher learning effects on awareness of privacy protection than those learned with the conventional methods.

• Journal of Auto-vehicle Safety Association
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• v.13 no.1
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• pp.31-37
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• 2021

SCMS is a security credential management system for V2X communication, which performs generation/ provision/validation of device's security certificates. In this paper, we will explain about the main functions of SCMS and the role of each institution, and propose the following improvement measures in the process of establishing the Korean V2X security certification system. First, connection scheme of ERA (Enrollment certificate RA) between SCMS and Vehicle Manager Information System (VIMS) will be proposed. Second part is the problem of certificate revocation and proposal of improvements.

• Journal of information and communication convergence engineering
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• v.20 no.4
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• pp.273-279
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• 2022

Owing to the need to establish a cooperative-intelligent transport system (C-ITS) environment in the transportation sector locally and abroad, various research and development efforts such as high-tech road infrastructure, connection technology between road components, and traffic information systems are currently underway. However, the current central control center-oriented information collection and provision service structure and the insufficient road infrastructure limit the realization of the C-ITS, which requires a diversity of traffic information, real-time data, advanced traffic safety management, and transportation convenience services. In this study, a network construction method based on the existing received signal strength indicator (RSSI) selected as a comparison target, and the experimental target and the proposed intelligent edge network compared and analyzed. The result of the analysis showed that the data transmission rate in the intelligent edge network was 97.48%, the data transmission time was 215 ms, and the recovery time of network failure was 49,983 ms.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.1
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• pp.1-7
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• 2023

TCP is considered a major candidate transport protocol even for constrained IoT networks due to its ability to integrate into the existing network infrastructures. Since TCP implementations such as uIP TCP often allow only a single TCP segment per connection to be unacknowledged at any given time due to resource constraints, the congestion control relies only on RTO management. In our previous work, to address the problem that uIP TCP performs poorly particularly when a radio duty cycling mechanism is enabled and the hidden terminal problem is severe, we proposed a RTO scheme for uIP TCP and validated the performance through Cooja simulation. In this study, we investigate the effect of other factors that were not considered in our previous work. More specifically, the effect of traffic intensity, the degree of the hidden terminal problem, and RDC is investigated by varying the offered load and the transmission range, and the RDC channel check rate. Simulation results imply that we need to further investigate how to improve TCP performance when the radio duty cycling mechanism is used.

• Journal of Korea Multimedia Society
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• v.25 no.2
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• pp.325-334
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• 2022

Digital twin has the advantages of quality improvement and cost reduction, so it is widely applied to various industries. In this paper, a method to implement the major technologies of digital twin easily and quickly is presented. These include data management and relay servers, real-time monitoring applications including remote control interfaces, and direct connection protocols for video streaming. In addition, an algorithm for controlling a two-wheeled vehicle with a 2D interface is also proposed. The implemented system performs near real-time synchronization between the real environment and the virtual space. The delay time that occurs in remote control of the vehicle in the real environment was compared with the results of applying the proposed delay time reduction method. In addition, in the case of 2D interface-based control, an algorithm that can guarantee the user experience was implemented and applied to the actual environment and verified through experiments.