• The KIPS Transactions:PartA
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• v.16A no.2
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• pp.101-112
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• 2009

Existing techniques for defragmentation of the file system need intensive disk operation for some periods at specific time such as disk defragmentation program. In this paper, for solving this problem, we design and implement the automatic and continuous defragmentation free system by distributing the disk operation. We propose the Automatic Layout Scoring(ALS) mechanism for measuring defragmentation degree and suggest the Lazy Copy mechanism that copies the defragmented data at idle time for scattering the disk operation. We search the defragmented file by Automatic Layout Scoring mechanism and then find for empty spaces for that searched file. After lazy copy of searched fils to empty space for preventing that file from being lost, the algorithm solves the defragmentation problem by updating the I-node of that file. We implement these algorithms in Linux and evaluate them for small and defragmented file to get the layout scoring. We outperform the Linux EXT2 file system by $2.4%{\sim}10.4%$ in layout scoring evaluation. And the performance of read and write for various file size is better than the EXT2 by $1%{\sim}8.5%$ for write performance and by $1.2%{\sim}7.5%$ for read performance. We suggest this system for solving the problem of defragmentation automatically without disturbing the I/O task and manual management.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.3
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• pp.8-15
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• 2010

Due to the increasing demand of network convergence, in future, hybrid/integrated satellite and terrestrial systems will play an important role. In that case, compatibilities between the satellite and terrestrial systems are very important for efficiency of the systems. 3GPP Long Term Evolution (LTE) is one of the most powerful candidates of the 4G system Therefore, in this paper, we introduce the design of interleaver for mobile satellite system based 3GPP LTE specification. The 4G system including the LTE specification adopted adaptive modulation and coding (AMC) schemes for efficient usage of resources, and the updating interval of resource allocation is an order of msec. However, because of the long round trip delay of satellite systems, we cannot employ the same AMC scheme specified for the terrestrial system, and thus it cannot effectively counteract to short term fadings. Therefore, in order to overcome these problems, we propose an interleaver scheme combined with AMC. We present the interleaγer design results considering mobile satellite system based on the LTE and analyze the simulation results.

• The KIPS Transactions:PartD
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• v.12D no.7 s.103
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• pp.947-956
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• 2005

Software(S/W) reengineering is one of the effective technologies to produce a business worth and en and the S/W ROI continuously. In spite of, S/W reengineering has been recognized a cost-consumptive works with inefficient productivity. In fact we have used to transform to confusion system with destructive system architecture by extending and updating legacy system in a temporary expedients. Moreover it is impossible to provide the time-market products for coping with rapid changeable system environment and meeting to complicated customer's requirements. Therefore, we need a systematic reengineering methodology to fulfill the changeable environment, as appearance of new IT techniques, various alteration of business information model, and increment of business logic. Legacy systems can be utilized as the core property in business organization through reengineering methodology. In this paper, we target to establish the reengineering process, proposed MaRMI-RE consisting of initial Planning phase, reverse engineering and component transformation phase. To describe the MaRMI-RE, we presented the concrete tasks and techniques and artifacts per individual phase in process, and the case study is showed briefly.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.5
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• pp.402-415
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• 2001

Advantages of flash memories are their shock resistance and fast read speed, which is much faster than that of a HDD. Because of these characteristics, they are increasingly used in the traditional household electric appliance and portable handset and therefore, development of file systems which use them as storage medium is increasingly needed. But they have two problems as storage medium. First, data stored in them cannot be overwritten: it must be erased before new data can be stored. Unfortunately, this erase operation usually takes about one second. Consequently, updating data in flash memories takes long time. In this paper, their problem is solved by using a data update mechanism like LFS(Log-structured File System). Second, their erase operations are restricted. We propose novel cleaning policy in order to increase the life cycle. We implemented FAT file system, which is suitable to small storage medium and solved problems, which usually happen in implementing FAT. We evaluated the performance of sequential writes and random writes on our implemented flash file system.

• Journal of Korea Game Society
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• v.9 no.3
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• pp.139-150
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• 2009

This paper attempts to investigate the establishment of an interactive knowledge base for action planning by virtual agents and an interactive knowledge-based planning system. A fixed knowledge base is unable to properly handle a change in circumstances because fixed planning is only available under a fixed knowledge base. Therefore, this paper proposes the establishment of an interactive knowledge base which is applicable to diverse environments and an artificial intelligence planning system in which an interactive knowledge base is available. The interactive knowledge base proposed in this paper consists of motivation, behavior, object and action. The association relationship between knowledge base and its input is set using an automation tool. With this tool, a user can easily add to or amend the components of the knowledge base. With this knowledge base, a character plans all action items and chooses one of them to take an action. Since a new action can be applicable by updating the knowledge base even when the character environment changes, it is very useful for virtual reality content developers. This paper has established a relationship between scalable interactive knowledge base components and other components and proposes a convenient input tool and a planning system algorithm effective for an interactive knowledge base. The results of this study have been verified through testing in a virtual environment ('virtual library').

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.175-178
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• 2008

While read operation on flash memory is fast and doesn't have any constraints, flash memory can not be overwritten on updating data, new data are updated in new area. If data are frequently updated, garbage collection, which is achieved by erasing blocks, should be performed to reclaim new area. Hence, because the number of erase operations is limited due to characteristics of flash memory, every block should be evenly written and erased. However, if data with access locality are processed by cost benefit algorithm with separation of hot block and cold block, though the performance of processing is high, wear-leveling is not even. In this paper, we propose CB-MG (Cost Benefit between Multi Group) algorithm in which hot data are allocated in one group and cold data in another group, and in which role of hot group and cold group is exchanged every period. Experimental results show that performance and wear-leveling of CB-MG provide better results than those of CB-S.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.1
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• pp.1-7
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• 2003

Practical use is increasing on the aerial ortho image recently, and much researches for geographic information system build that use high resolution satellite image cause this are progressing. Also many researches that use KOMPSAT-1 satellite image of resolution 6.6m are performing in these days, estimation for between aerial photo and satellite image is needed. In this treatise scanned image of aerial photo, using aerial photo resampling image of resolution equal with KOMPSAT-1 image using aerial photo, and KOMPSAT-1 satellite image use for experimental image making each orthoimage, classified feature for estimate. We evaluated to what level that an separation item could be able to estimate in each orthoimage. As result of estimation analysis, In the classified feature in aerial photo orthoimage with aerial photo resampling image orthoimage is about 61%, KOMPSAT-1 satellite image orthoimage is almost 41% could estimated. Through this investigation estimate, KOMPSAT-1 satellite sue to map updating, geographic information og non-approach area and environment inspect.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.6 s.52
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• pp.103-114
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• 2006

Forced vibration testing is important for correlating the mathematical model of a structure with the real one and for evaluating the performance of the real structure. There exist various techniques available for evaluating the seismic performance using dynamic and static measurements. In this paper, full scale forced vibration tests simulating earthquake response are implemented by using a hybrid mass damper. The finite element (FE) model of the structure was analytically constructed using ANSYS and the model was updated using the results experimentally measured by the forced vibration test. Pseudo-earthquake excitation tests showed that HMD induced floor responses coincided with the earthquake induced ones which were numerically calculated based on the updated FE model.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1197-1202
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• 2017

Security services that support electric energy service gateway require relatively high reliability. In particular, the application services that accompany communications and data are run organically. Each of the security services should support a secure service platform that supports a secure, scalable life cycle for existing services which should be extends security layer of Universal Middleware. In this convergence platform, it is the study of security transfer modular services that allow independent life cycle management of systems through Universal middleware. First, It is modular in terms of energy consumption service and data, enabling real-time operation, communications, remote management and applications. Second, the life cycle of the secure module to support start, stop and updating of the security module by applying the security policy module layer concept. It is modular system enabling to design of dyanmic models in the smart grid, the service was intended to be standardized and applied to the security service platform.

• Journal of Communications and Networks
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• v.17 no.1
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• pp.75-83
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• 2015

In mobile ad-hoc networks (MANETs), nodes are mobile in nature. Collaboration between mobile nodes is more significant in MANETs, which have as their greatest challenges vulnerabilities to various security attacks and an inability to operate securely while preserving its resources and performing secure routing among nodes. Therefore, it is essential to develop an effective secure routing protocol to protect the nodes from anonymous behaviors. Currently, game theory is a tool that analyzes, formulates and solves selfishness issues. It is seldom applied to detect malicious behavior in networks. It deals, instead, with the strategic and rational behavior of each node. In our study,we used the dynamic Bayesian signaling game to analyze the strategy profile for regular and malicious nodes. This game also revealed the best actions of individual strategies for each node. Perfect Bayesian equilibrium (PBE) provides a prominent solution for signaling games to solve incomplete information by combining strategies and payoff of players that constitute equilibrium. Using PBE strategies of nodes are private information of regular and malicious nodes. Regular nodes should be cooperative during routing and update their payoff, while malicious nodes take sophisticated risks by evaluating their risk of being identified to decide when to decline. This approach minimizes the utility of malicious nodes and it motivates better cooperation between nodes by using the reputation system. Regular nodes monitor continuously to evaluate their neighbors using belief updating systems of the Bayes rule.