• Journal of the Korea Society of Computer and Information
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• v.15 no.2
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• pp.155-162
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• 2010

To ensure accurate measurements of wireless network performance, it should be collected real-time data which are transmitted between a large number of nodes in the actual network environment. Therefore, it is necessary to develop simulation tool for finding optimal network system design method such as media access control, routing technique, ad-hoc algorithm of node deployment while overcoming spatial and temporal constraints. Our research attempts to provide an improved architecture and design method of simulation tool for wireless network is an application of multi-threading technique in these issues. We finally show that usability of the proposed simulator by comparing results derived from same test environment in the wireless LAN model of our simulator and widely used network simulation package, NS-2.

• The Journal of Korean Association of Computer Education
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• v.8 no.4
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• pp.87-95
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• 2005

A large part of the wireless Internet contents which the young people access through their mobile phones is mobile games. However, mobile games currently available in the market are mostly simple entertainment packages, and there are hardly any educational game contents. This research divided the middle school computer education curriculum into five parts-common PC knowledge, operating systems, word processor, Internet, and multimedia-and designed and implemented a crossword puzzles mobile game. The mobile game designed in this research was given an emphasis to allow access of school lesson contents anywhere and anytime through actual mobile telecommunication networks, so that the students may experience less barrier to more fun and entertaining educational contents. The developed educational mobile game was applied on 2nd year middle school students. The mobile game had positive educational effects.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1289-1300
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• 2011

In recent computer systems with high-performance, users execute programs needing large memory and programs intensively accessing files simultaneously. Such a large memory requirement makes virtual memory systems access swap spaces in disk, and intensive file accesses require file systems to access file system partitions in disk. Executing the two kinds of programs at once incurs large disk seeks between swap spaces and file system partitions frequently. To solve the problem, this paper proposes a new scheme called SAF to create several swap spaces in a file system partition, where pages to be paged out are stored. When a page is paged out, the scheme stores the page to one of the swap spaces close to a disk location where the most recently accessed file is located. The chosen swap space in the file system partition is closer to the disk location than the traditional swap space, so that our scheme can reduce the large disk seek time spent to move to the traditional swap space in paging out a page. The experiment of our scheme implemented in FreeBSD 6.2 shows that SAF reduces the execution time of several benchmarks over FreeBSD ranging from 14% to 42%.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.10
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• pp.413-420
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• 2013

Redundant arrays of independent disks (RAID) without a power-fail-safe component in small and mid-sized business suffers from intolerably long resynchronization time after a unclean power-failure. Data blocks and a parity block in a stripe must be updated in a consistent manner, however a data block may be updated but the corresponding parity block may not be updated when a power goes off. Such a partially modified stripe must be updated with a correct parity block. However, it is difficult to find which stripe is partially updated (inconsistent). The widely-used traditional parity resynchronization manner is a intolerably long process that scans the entire volume to find and fix inconsistent stripes. This paper presents a fast resynchronization scheme with a negligible overhead for small and mid-sized RAIDs. The proposed scheme is integrated into a software RAID driver in a Linux system. According to the performance evaluation, the proposed scheme shortens the resynchronization process from 200 minutes to 5 seconds with 2% overhead for normal I/Os.

• Convergence Security Journal
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• v.18 no.5_1
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• pp.67-73
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• 2018

From a software engineering point of view, tracing is a special form of logging that records program execution information. Tracers using dedicated hardware are often used because of the characteristics of tracers that need to generate and decode huge amounts of data in real time. Intel(R) PT uses proprietary hardware to record all information about software execution on each hardware thread. When the software execution is completed, the PT can process the trace data of the software and reconstruct the correct program flow. The hardware trace program can be integrated into the operating system, but in the case of the window system, the integration is not tight due to problems such as the kernel opening. Also, it is possible to trace only a single process and not provide a way to trace multiple process streams. In this paper, we propose a method to extend existing PT trace program to support multi - process stream traceability in Windows environment in order to overcome these disadvantages.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.2
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• pp.1-8
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• 2011

An underwater robot S/W framework consists of various sub-modules such as sensory data processing module, thruster control module, cognition module and behavior control module. Performance of a robot is determined by not only the efficiency of algorithms used but also effectiveness of their implementations. One most important factor of the effective implementation is the efficiency of data sharing module, as it transmits signals and data between the sub-modules and thus is directly related to the cycles of sensing and control The ideal data sharing module enables immediate access to any data source irrespective of system configurations. In reality, however, there are lots of obstacles including limitation of processing capacity of source modules, delay over network, and scheduling latency of operating systems. The paper proposes a new data sharing architecture and programming models to effectively handle such obstacles in implementation of underwater S/W framework on a small scale distributed computing system.

• Journal of Internet Computing and Services
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• v.3 no.4
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• pp.95-102
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• 2002

A continuous development of new hardware and operating systems brings the importance of portable programming, which can be imported into multi-platform environment. Also, the recent development of computer communication technology brings us many choices of accessing into the other platforms, which also becomes a burden for the programmers who should consider developing software fitting into diverse platforms The present GNU system tools creates a part of the source code automatically, and suggests a direction towards a new platform. but the source code must be prepared by the programmer at the source level. In this paper, we describe design and implementation of on interactive tool for developing multi-platform software, The tool is designed to help a programmer to build a portable program for multi-platform, even though the programmer does not know very well about various UNIX platforms, And, the tool uses existing GNU system tools, such as autoconf, autoheader, automake and etc, and is able to insert a portable code into a right position by interacting with a programmer.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.750-753
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• 2006

e-Learning 분야는 정부, 기업, 학교 등 많은 조직에서 교육을 위한 수단으로 사용되어지고 있다. 이러한 e-Learning은 독립적인 운영플렛폼의 개발부터 웹 기반의 코스웨어(Courseware)까지 발전해왔다. 코스웨어는 컴퓨터 전달 체제를 통하여 교수-학습 과정을 촉진시켜 명시된 교수 목표 하에 학습자의 지식과 기능의 바람직한 변화를 목적으로 설계 및 개발된 교육용 소프트웨어와 데이터라고 할 수 있다. 또한 컴퓨터 언어 및 저작도구(Authoring Tools)를 이용하여 각 과목별 교육내용을 음성, 그림, 애니메이션, 동영상 등의 다양한 형태로 제시될 수 있도록 저작된 프로그램으로 주로 눈으로 보고 귀로 들으면서 학습하는 유형이다. 현재 코스웨어에서 제공되는 정보는 학습에 대한 정보와 교수정보 그리고 Client의 학습 진행 상황 등을 제공한다. 하지만 학습에 연관된 다른 학습이나 학습에 관련된 교수들의 전공정보, 또한 학습에 관련된 어플리케이션 등을 검색하려 할 때는 하나하나 따로 검색을 해야 하는 어려움이 따른다. 본 논문에서는 이러한 문제점을 해결하기 위하여 학습에 대한 목적과 관련학습, 관련교수, 관련연구, 관련 어플리케이션 등의 연관성을 토픽맵(TopicMap)을 이용하여 학습에 대한 더 정확한 정보를 쉽게 검색할 수 있게 한다. Client가 찾으려는 토픽을 중심으로 연관된 토픽과 카테고리를 나열하여 수작업으로 인한 검색시간과 잘못된 키워드 검색을 해결하였다.

• Science of Emotion and Sensibility
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• v.9 no.2
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• pp.93-100
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• 2006

This paper aims at the development and clinical evaluation of the wireless gyro-mouse system. The wireless gyro-mouse system is a computer interface with gyro-sensor and wireless communication, for the patients with upper-extremity disabled from the traffic accident or stroke to use the computer software i.e. internet browser. In the development, we focused on, firstly, to make the system wireless for the patients to manipulate the mouse easily even on the bed or wheelchair, secondly, to insert the gyro-sensor into a headband for easy don-and-doff and aesthetic appearance, thirdly, to devise a click switch in case of $C5{\sim}C6$ patients and a head nodding detection in case of C4 patients for sending click message to computer operating system. We performed evaluation experiment for patients with upper-extremities disabled from spinal cord injury. The results show that the displacement error of the cursor position against the target position during linear (vertical/horizontal) movement manipulation decreased with trial number. The click rate per minute also increased with trial number. This indicates the developed wireless gyro-mouse system would be more useful to the patients with repetitive use.

• KOMUNHWA
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• no.57
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• pp.301-314
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• 2001

1) Traditional university museums use displays and photo collections of antiquities as means for educating present and future generations. But the success in their mission hinges on whether they can induce the gallery to visit the places. Fortunately, sin