• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.11
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• pp.2404-2410
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• 2011

This paper describes the design overview of cluster file system $SANique^{TM}$ based on SAN(Storage Area Network) environment. The design issues and problems of the conventional global buffer manager are also illustrated under a large set of clustered computing hosts. We propose the efficient global buffer management method that provides the more scalability and availability. In our proposed global buffer management method, we reuse the maintained list of lock information from our cluster lock manager. The global buffer manger can easily find and determine the location of requested data block cache based on that lock information. We present the pseudo code of the global buffer manager and illustration of global cache operation in cluster environment.

• Journal of Korea Multimedia Society
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• v.7 no.4
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• pp.505-517
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• 2004

This paper overviews the design details of the cluster file system $\textrm{SANique}^{TM}$ on the SAN environment. $\textrm{SANique}^{TM}$ has the capability of transferring user data from shared SAN disk to client application without control of centralized file server. We, especially, focus on the characteristics and functions of recovery manager CRM of $\textrm{SANique}^{TM}$. The process component for failure detection and its overall procedure are described. We define the split-brain problem that cannot be easily detected in cluster file systems and also propose the recovery management method based on SAN disk in order to detect and solve the split-brain situation.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.547-549
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• 2007

Recently with increasing the use of parallel computing and cluster system which was connected high speed network, the interest about distributed and parallel file system is increasing. Specially, there are many researches, which focused on optimizing the performance of distributed and parallel file system for the more efficient use of cluster system. In this paper, we analyzed the performance of PVFS(Parallel Virtual File System) in small cluster system. In addition, to improve the PVFS performance we proposed the chancing the size of flow buffer according to the network speed and we optimized the PVFS performance on small cluster system.

• KIISE Transactions on Computing Practices
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• v.20 no.11
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• pp.592-597
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• 2014

In this paper, we propose an adaptive transformation engine that provides smart devices with optimal user interfaces and media contents to their characteristics so as to conveniently control home networks remotely using smart devices in the wired and wireless home networks which various kinds of smart devices and home network devices are connected. The proposed engine dynamically transforms UI contents and transfers them using device profiles and UI transformation policies to make it suitable for smart devices. Moreover, the proposed engine offers suitable media contents for smart devices through capabilities of real-time media transcoding and streaming considering device and media profiles.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.2
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• pp.99-105
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• 2007

In this paper, diskless personal multimedia player(PMP) that can access and decode the remote large multimedia data is implemented via wireless network. To implement this, WLAN based NFS protocol is used to connect PMP to the remote server and text image and movie files are decoded and played using ARM9 cored PXA255 embedded processor and Linux OS. The fuction and performance of the PMP is evaluated and verified using variuos types of contents. Linux kernel elements are configured and built in according to the hardware and software on the target board to install on the target board. The confirming result shows the required functions and performances.

• Annual Conference of KIPS
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• 2003.05a
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• pp.675-678
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• 2003

현대 사회에서 가스 산업은 기반 기순 산업으로 영향력이 매우 커지고 있으며, 동시에 위험요소를 내포하고 있다. 본 논문은 가스밸브의 연결부분에서 폭발성 발화물질인 오일성분에 의한 안전사고를 방지하고자 유지분 검출시스템을 개발하였다. 용기 밸브의 영상을 $200{\times}200$ 크기의 흑백 이미지로 획득하고, 제안한 유지분 검출 알고리즘을 적용한다. 먼저, 영상에 소벨(Sobel) 연산자를 이용하여 에지(Edge)를 검출하고 오일이 존재하는 영상과 오일이 존재하지 않는 영상을 영상프로파일(image profile) 분석과 영상 감법 둥의 검출방법으로 비교 분석하였다. 첫 번째 방법은 영상프로파일기법으로 3가지 영역인 부분영역, 하위영역, 전체영역으로 오일을 삽입한 후 다항식 근사로 오일의 존재여부를 판별하였고, 두 번째는 영상감법으로 밸브의 특정한 위치에 위치조정표시를 한 후 두 영상의 차를 구하였다. 실험에서는 제안한 검출방법의 실용화 가능성을 확인하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1049-1061
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• 2013

In this paper, a relative heat exchange rate is numerically compared for cast-in-place concrete energy piles with different heat exchange pipe configurations, and a new design method for energy piles is proposed. An equivalent heat exchange rate was estimated for the W-type (one series loop), multiple U-type (four parallel loops), and coil-type heat exchanger installed in the same large-diameter drilled shaft. In order to simulate a cooling operation in summer by a CFD analysis, the LWT (leaving water temperature) into a energy pile was fixed at $35^{\circ}C$ and then the EWT (entering water temperature) into a heat pump was monitored. In case of continuously applying the artificial maximum cooling load for 100 hours, all of the three types of heat exchangers show the marginally similar heat exchange rate. However, in case of intermittently applying the cooling load with a cycle of 8 hours operation-16 hours off for 7 consecutive days, the coil type heat exchanger exhibits a heat exchange rate only 86 % of the multiple U-type due to measurable thermal interference between pipe loops in the energy pile. On the other hand, the W-type possesses the similar heat exchange rate to the multiple U-type. The equivalent heat exchange rates for each configuration of heat exchangers obtained from the CFD analysis were adopted for implementing the commercial design program (PILESIM2). Finally, a design method for cast-in-place concrete energy piles is proposed along with a design chart in consideration of typical design factors.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.538-585
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• 1998

이동 컴퓨팅 환경에서 이동 호스트는 무선망을 통해 서버와 연결된 후에서야 데이터를 획득 및 처리할 수 있다. 그러나, 이동 호스트는 낮은 대역폭과 이로 인한 지연, 네트워크 단절(disconnection)과 같은 무선망의 특성으로 인하여 사용상에 많은 불편함과 비효율성이 발생하고 있는 실정이다. 특히, 이동 호스트가 네트워크 단절로 인해 서버에 접근이 불가능하고 작업에 필요한 데이터가 캐쉬에 없을 경우에는 작업 처리가 불가능하다. 본 논문에서는 이와 같은 문제점을 해결하기 위하여 이동 호스트가 미래에 작업할 데이터를 미리 인출해서 캐쉬에 저장하는 선인출 메카니즘을 제안하였다. 본 논문의 선인출 메카니즘을 기록기, 분석기, 선인출 목록 생성기, 그리고 비교기로 구성된다. 기록기와 분석기는 이동 호스트의 파일 참조 패턴들을 기반으로 프로파일을 생성하며, 선인출로 인한 성능 감소를 최소화하기 위해 선인출과 캐쉬 교체 전략을 통합한 선인출 메카니즘을 제시하였다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.2
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• pp.99-104
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• 2015

This study analyzed the effects on displacement and stress as a result of improving the profile fastening method targeting rectangular-shaped and cube-shaped specimens. For the rectangular-shaped specimens, the improved fastening method reduced maximum displacement to 41.7% and maximum stress to 18.3% compared to the existing fastening method. For the cube-shaped specimens, maximum displacement and maximum stress results were found to be similar to those of the rectangular-shaped specimens. Thus, as a result of comparing the stress and displacement of the existing and improved fastening methods, it was found that the improved fastening method is superior to the existing fastening method in terms of load support.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.06a
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• pp.37-41
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• 2001

모바일 인터넷 시대가 열리면서 언제, 어디서든지 네트워크에 연결될 수 있는 휴대용 디지털 기기의 인터넷에 대한 관심이 증대되고 있다. 모바일 단말기에서의 자바 플랫폼 기반 지니 홈네트워크 접속은 자바 기술의 특성을 가장 잘 살린 컴퓨팅 환경이다. 지니를 지원하기 위해서는 자바 가상 기계라는 소프트웨어가 실행을 하고 있는 환경이어야 하고 RMI를 지원해야 하는데 Java2ME의 K-자바 가상 기계는 이를 지원하지 못한다. 본 논문에서는 Java2ME CLDC를 기반으로 지니에 접속할 수 있는 자바 가상 기계에 대해 논의하였다. 지니 KVM 은 각 모바일 단말기에 맞는 프로그램을 하지 않아도 되는 환경을 제공 할 뿐만 아니라, 표준 자바 클래스 파일 포맷과 CLDC 클래스 파일을 지원하고, 지니에 접속할 수 환경을 제공함으로써, 모바일 단말기의 본격적인 네트워킹을 할 수 있도록 한다.