• Journal of the Korea Society of Computer and Information
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• v.16 no.4
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• pp.205-214
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• 2011

With the success of Kindle, an electronic book reader developed by Amazon.com, there has been a growing interest in both electronic books and readers in Korea. In this paper, we analyze electronic book user needs through fuzzy analytic hierarchy process (AHP) and conjoint analysis. First, we select the important factors which can affect the intention to purchase electronic book readers by applying the fuzzy AHP with the help of electronic book experts. Next, we perform conjoint analysis to reveal the detailed needs of electronic book users for each of the selected factors. Some useful implications and research limitations are also presented with future research directions.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10a
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• pp.364-366
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• 2000

컴포넌트 기반의 개발과 컴포넌트 개발에 대한 관심이 높아지면서 이를 위하 개발 방법론과 개발 도구들의 도입이 확산되고 있다. 또한 컴포넌트의 재사용 범위를 확장시키기 위해 컴포넌트 개발 시 나타나는 Hot Spot 처리를 위한 분석, 설계 기법에 대한 관심이 높아지고 있다. 따라서 본 논문에서는 이러한 분석, 설계기법을 이용하여 융통적인 계층적 접근 권한에 대한 분석, 설계 모델을 제시한다. 본 논문에서는 다지인 모델링을 위한 표기법으로서 객체지향 모델링 기법인 UML(Unified Modeling Language)를 이용하여 모델링 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.7
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• pp.1617-1625
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• 2010

Recently, the standardization of SVC technology which can provide adaptive video quality in diverse service environments has been completed. This paper proposes a layered encryption technique which takes into account the prioritized layer characteristics of SVC and control constant encryption complexity satisfying the target computational complexity. In particular, it analyzes the importance of NAL unit in the SVC video layer and suggests a method to apply appropriate encryption complexity proper for it. The effectiveness of the proposed method is proved through the comparison of time required for encryption and the reconstructed video quality using imperfect decryption key.

• Journal of KIISE:Information Networking
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• v.30 no.3
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• pp.316-328
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• 2003

In this paper, we propose and analyze two adaptive channel allocation schemes for supporting multimedia traffics in hierarchical cellular systems. It is guaranteed to satisfy the required quality of service of multimedia traffics according to their characteristics such as a mobile velocity for voice calls and a delay tolerance for multimedia calls. In the scheme 1, only slow-speed voice calls are allowed to overflow from macrocell to microcell and only adaptive multimedia calls can overflow from microcell to macrocell after reducing its bandwidth to the minimum channel bandwidth. In the scheme II, in addition to the first scheme, non-adaptive multimedia calls can occupy the required channel bandwidth through reducing the channel bandwidth of adaptive multimedia calls. The proposed scheme I is analyzed using 2-dimensional Markov model. Through computer simulations, the analysis model and the proposed schemes are compared with the fixed system and two previous studies. In the simulation result, it is shown that the proposed schemes yield a significant improvement in terms of the forced termination probability of handoff calls and the efficiency of channel usage.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05c
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• pp.303-307
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• 2002

디지털 영상압축 방법인 ITU-T H.263++ 부호화기법 중에는 계층 모드(scalability mode)를 지원한다. 계층 모드는 한 개의 송신 영상에 대해서도 복호기와 전송로에 따라서 여러 가지 화질의 재생 영상을 얻을 수 있게 한다. 계층 모드는 시간적, 공간적, SNR(signal-to-noise ratio)로 나누어진다. 그 중에서 SNR 계층 모드는 고급계층에 따라서 다양한 해상도를 가질 수 있다. 계층부호화에는 크게 기본계층과 고급계층으로 나누어지는데, 기본계층은 QoS를 보장하여, 화질은 떨어지나 에러 없이 영상을 전송하고, 고급계층에서는 기본계층에 해상도 에러에 대한 나머지 정보를 전송한다. 고급계층으로 전송되는 정보는QoS가 보장되지 않으므로 비트에러나, 팻킷 에러가 발생 할 수 있다. 따라서 고급계층에 에러가 발생하게 되고, 에러 전파 현상이 일어난다. 본 논문에서는 단일계층부호화와 2 Layer 계층부호화에서 발생되는 에러의 차이점을 알아보고, 데이터 손실 없는 기본계층과 에러가 발생하는 고급계층에 상관관계를 분석하여, SNR계층부호화에서 맞는 고급계층 에러은닉 기법을 제안한다.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.9-21
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• 2013

Tracking is a process which explores user equipment (UE) in the area of tracking in terms of cells. In this paper, two tracking schemes based on macrocell-microcell tiers in hierarchical LTE networks, PMMT and IMMT, are evaluated. In this network, UE can receive a signal from macrocells and overlapping microcells, and can be called from each macrocell or microcell-tier in the PMMT. Also, the UE can be called from the combined macrocell-tier and microcell-tier in the IMMT. Finally, we analyze the optimization of load balance between marcocell-tier and microcell-tier, and an analytical model is developed to evaluate those two arrangements.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.5
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• pp.457-461
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• 2008

Previous studies on overlay ad hoc multi-casting are mainly divided into two categories: hierarchical structure-based multicast schemes and non-hierarchical structure-based multicast schemes. They do not reflect their real-time location information for routing updates. This can be a cause of low performance on energy consumption, throughput, and latency. For improving the problems, we propose an implicit cluster based overlay ad hoc multicast scheme with analysis of related work, and then we evaluate performance through computer simulation.

• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.440-447
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• 2011

Selecting a suitable place is to determine the attributive conditions and qualified areas for the aim as factors and is to be fulfilled systematically for selecting the area which satisfies all these. This research tries to achieve a rational suitability analysis of residential development using the GIS modeling method and the hierarchical analysis process. A spatial and attributive analysis has been systematized for selecting a suitable place for the study and GIS analysis model has been used for the effective conclusion drawing for different levels. As a next step, a quantitative and qualitative evaluation index was created through complex consideration of the criteria and decision factors of the location selection, and weights were added depending on the relative importance of these factors. In particular, 3D terrain model simulation method has been used in order to reflect the aesthetic factors of the scenery which is an element of the subjective evaluation factors and considered qualitative and subjective evaluation factors which were not considered for the existing AHP technique. After the research, a location that satisfies complex requirements was found rapidly and accurately through the GIS model and hierarchical analysis.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.709-711
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• 1998

범 구조적 병렬 컴퓨팅 모델인 린다 모델의 비결합성, 확장성, 부하균등, 동기화 문제 해결과 같은 많은 특성을 가지고 있는 반면, 튜플 스페이스로의 메시지 집중 현상으로 전체 시스템의 성능을 저하시키는 결정적인 문제를 안고 있다. 따라서 본 논문에서는 계층적 튜플 스페이스를 제공함으로써 기존 린다 모델의 장점을 모두 수용함과 동시에 메시지 집중 현상을 줄일 수 잇는 계층적 튜플 스페이스 린다 몰델을 제안한다. 또한 RP층적 튜플 스페이스를 구성하기 위한 병렬 코드 생성 방법을 모색하고, 그 과정에서 분석결과 및 프로그램성능 분석을 통해 실제 시스템에 균등하게 사상함으로써 전체적인 프로세서의 효율적인 수행을 가능하게 하는 사상 기법을 제안한다.

• Journal of Information Management
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• v.40 no.2
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• pp.95-115
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• 2009

Author resolution is to disambiguate same-name author occurrences into real individuals. For this, pair-wise author similarities are computed for author name entities, and then clustering is performed. So far, many studies have employed hierarchical clustering techniques for author disambiguation. However, various hierarchical clustering methods have not been sufficiently investigated. This study covers an empirical evaluation and analysis of hierarchical clustering applied to Korean author resolution, using multiple distance functions such as Dice coefficient, Cosine similarity, Euclidean distance, Jaccard coefficient, Pearson correlation coefficient.