• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.2
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• pp.87-95
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• 2010

A Vehicular Ad-Hoc Network (VANET) is form of the Mobile Ad-hoc Network (MANET) to provide temporary communication among vehicles via wireless links. In VANET, the vehicle is one of the nodes in networks and communicates with each other. However, the wireless links disconnect very frequently, because vehicles have mobility and move freely. The reason why data accessibility degrades is that disconnection occurs frequently. To improve data accessibility, data replica allocation methods that made group to allocate data replica have proposed in MANET. However, those are not suitable because it is difficult to maintain stable links among the nodes moving fast by centralized group. In this paper, we proposed TBG (Tree Based Grouping) to allocate data replica with the distributed grouping method. Each node has own TBG and allocates data replica based on stability of links to improve data accessibility. The experiment demonstrates that the proposed method outperforms traditional methods in term of data accessibility.

• Journal of Korea Multimedia Society
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• v.11 no.7
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• pp.928-939
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• 2008

The grid database management system is used for large data processing, high availability and data integration by grid environment. It has a replica for processing performance and high availability in each node. The grid database has a problem of inconsistency, when the update is occurred with a coincidently frequent. To solve this problem, in this paper proposed a version management method for consistency in the grid database. Proposed version manager manages a version of each replica. The version manager keeps a consistency of update operation when is occurred at each node by using a pending queue and waiting queue. Also the node keeps a consistency using a priority queue. So, proposed method has stable and fast update propagation. The proposed method shows stable and faster update propagation than traditional method by performance evaluation.

• Korean Journal of Microbiology
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• v.32 no.3
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• pp.186-191
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• 1994

The origin of the leading strand replication (ori) and of lagging strand replication (M-O) of R-plasmid pSBK203 was identified and its base sequence was determined. About 50 bp of ori sequence residues overlapped with the structural gene of rep. Sequence comparison reveals that pSBK-ori shares obvious identities with those of pT181 family and consists of two regions, one is conserved and the other is variable region. Of two palindrome sequence located one after another in upstream region of rep gene, palA' instead of palA which shares sequence homology with diverse family of plasmids such as pOX6, pC194, and pE194 seems to act as a signal for conversion of primarily replicated ssDNA to dsDNA (minus origin (M-O)).

• Journal of Internet Computing and Services
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• v.12 no.6
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• pp.1-17
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• 2011

The performance of DHCS depends on the algorithm which schedules input DAG. However, as the task scheduling problem in DHCS is an NP-complete problem, heuristic approach has to be made. Task scheduling algorithm consists of task prioritizing phase and processor allocation phase, and most of studies are considering both phases together. In this paper, we focus on task prioritizing phase and propose a WPD algorithm which is optimized for task duplication based processor allocation method. For an evaluation of the proposed WPD algorithm, we combined WPD algorithm with processor allocation phase of HMPID, HCPFD, HCT algorithms, which are using task duplication based processor allocation method. The results show that WPD algorithm makes a better use of task duplication than conventional task prioritizing methods and provides 9.58% better performance than HCPFD algorithm, 1.31% than HCT algorithm.

• The Journal of the Korea Contents Association
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• v.15 no.5
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• pp.550-559
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• 2015

Despite of the long history of comic industry in Korea, self-motivated sound ecosystem is not determinded due to the pirated contents. The file-sharing literature has focused mainly on how pirated contents could be eradicated, with less attention to the effective strategy. This research is focusing more on pirate comic market within the framework of users. The target user is people who pay for using file sharing site. The research methods are a online survey and a written interview. The goal of this research is to analyze the correlation between morality and websites uses, the user convenience of file-sharing site and the main factors for attracting user to legal portal site. According to our results, legal portal sites needs to improve purchasing factors such as diversity of contents, improvement of payment system and offer of a detailed information.

• Journal of Internet Computing and Services
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• v.4 no.6
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• pp.87-93
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• 2003

Data Replication makes distributed system and database system improved in availability and performance. But it is difficult to keep strict consistency in data update. Existing algorithms keep strict consistency, but have problems of cost a great deal and delay time. It is to introduce hybrid update propagation algorithm which permits eager update for original copy and propagates lazy update for other copies. Hybrid update propagation algorithm also permits group update in ownership. This algorithm menages replica version in order to control group update consistency. Consistency and performance is improved by combining eager update and lazy update with group ownership. Simulation shows improvement of transaction throughput and response time depending on application and execution environment.

• Annual Conference of KIPS
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• 2008.11a
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• pp.1276-1279
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• 2008

최근 모바일 장치의 증가와 무선 네트워크 환경의 발전은 모바일 애드혹 네트워크에 대한 관심을 증가시키고 있다. 최근까지의 연구는 모바일 애드혹 네트워크에서 데이터 접근성(Accessibility) 향상을 위해 복제의 활용이 효율적임을 증명하고 있다. 복제 기법이 모바일 애드혹 네트워크에서 실제로 활용되기 위해서는 원본과 복제본 사이에 일관성(Consistency)이 확보되어야만 한다. 기존의 연구에서는 일관성 확보를 위해 원본을 가진 노드에게 확인하는 기법을 활용하고 있다. 그러나, 시간제약을 가지는 응용의 경우 원본을 가진 노드에게 확인하는 기법은 효율적이지 못하며, 때로는 심각한 문제를 일으킬 수도 있다. 본 논문에서는 시간제약응용을 위한 캐쉬 무효화 기법을 제안하고 있다. 제안하는 기법을 통해 기존의 일관성 확인 기법에서 일어나는 '롤백(Rollback)' 문제를 해결할 수 있었으며, 접근시간(Access time) 측면에서 성능향상을 얻을 수 있었다. 실험 결과는 본 논문의 접근시간 측면에서의 효율적임을 증명하여 준다.

• The KIPS Transactions:PartD
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• v.8D no.5
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• pp.605-612
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• 2001

In order to solve the overload of academic affairs management system, we propose a method builds a distributed Replication server and uses this server with the present centralized system. Normal query transactions which are not required for data modification are composed of almost all DML sentences. So we construct the distributed replication servers according to the data characteristics and make them perform the query transaction without modification. In this way, we can simultaneously distribute users and data, and cut down processing time for every transaction. Also Replication server has the advantages of implemental efficiency and economical because it uses resources of present centralized system without and additional configurations. Usually, to distribute the overload of server, they can use way, Client-side overload distribution that user program get present overload status then can choose a less overloaded server, and the other way, Server-side overload distribution that make use of Application Layer Scheduling Technique and IP Layer Scheduling Technique. Our Replication server can reduce the overload of centralized system by eliminating or complementing those defects of overload distribution, referred to in the forehead.

• Journal of Internet Computing and Services
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• v.2 no.5
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• pp.71-79
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• 2001

Replication in distributed databases is to improve efficiency, availability, and autonomy, But applying the strict consistency in real systems is very difficult. In this paper, I introduce a hybrid protocol permitting group update through eager update propagation and weakening consistency through lazy update, This protocol manages replica version number for the group update consistency and generates partially ordered replica spanning tree for the serializability of lazy update transactions. It preserves weak consistency by combining synchronous and asynchronous update mechanism. Study of performance analysis for the efficiency of the protocol be included in next paper.

• Cartoon and Animation Studies
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• s.46
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• pp.207-231
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• 2017

Printmaking is a field of fine arts and is placed on a vague boundary that is perceived as a commercial product with a popular character due to the speciality of editions. Advances of modern science and technology has developed a new technique of printmaking, and the fusion of printmaking and computer has shown the possibility of reproduction art. Reproduction printmaking has been heavily influenced by photography and extended areas, and the various forms of printing have brought about many changes and attempts by stimulating the possibilities of indirect art at various angles. As the history of printmaking and technology closely relate, the development of computer makes widespread expansion of plural artistry, technological and artistic change. A new conceptual shape can be created on the copied image simply by placing the material of the print on the smoothly flat surface expressed in digital form. The process and the result of such work show the area of unique work which is different from the value of the $\grave{a}$ la carte art or the characteristics of the material given by the print. The deprecated perception of reproducibility evaluated the value of the work in a direct sense of printmaking. It is undeniable that it is devalued by a bundle of works regardless of the value of each edition. However, the physical properties of the prints on the paper are brought up with hand drawings drawn on the canvas by hand. And it becomes an opportunity to show new aspect and change through the process of combining digital print information on paper. The diversity of media is sometimes a controversy of identity between art and technology. In the future, it should be discussed how the limit of the media which can be enjoyed in the field of art can be set as a standard.