• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.331-333
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• 2015

네트워크와 모바일 기기의 확산으로 데이터가 폭발적으로 증가하고 있으며 기존의 추천 기법으로는 급증하는 데이터를 효율적으로 처리하는데 문제가 있다. 따라서 가장 널리 사용되는 추천 기법인 협업 필터링 기법의 확장성 문제를 어떻게 해결할 것에 대한 연구들이 진행되고 있다. 본 논문에서는 협업 필터링 기법에 분산 병렬처리 방식인 MapReduce를 적용하여 확장성 문제를 줄이고 정확성을 높이는 기법을 제안한다. 제안하는 기법은 사용자 기반 협업 필터링 기법에 MapReduce와 색인기법을 적용하여 유사도 계산에 사용되는 이웃의 수와 이웃의 적합성을 개선하는 방식으로 확장성과 정확성을 개선하는 효과를 기대할 수 있다.

• International Journal of Contents
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• 제16권1호
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• pp.25-33
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• 2020

We develop a simulation method that affords very high variability of virtual pedagogical situations involving many independent plans, still achieves authoring (or implementation) scalability. While each individual plan would be coherently drawn up by an agent for its respective goal, those independently-made plans might be coincidentally intertwined in their execution. The inevitable non-determinism involved in this multi-event plan encompassing pre-planned and unforeseen events is resolved by (multi-phase) dynamic planning and articulated sequencing of events in contrast to static planning and monolithic authoring in conventional narrative systems. Connections between events are dictated by their associated rules and their actual connections are dynamically determined in execution time by current conditions of background-world. This unified connection scheme across pre-planned and unforeseen events allows a multi-plan, multi-agent situation to be coherently planned and executed in a global scale. To further the variability of a situation, the inter-event coupling is made in a fine level of action along with a limited episteme of each agent involved. We confirm analytically the viability of our approach with respect to the situation variability and authoring scalability, and demonstrate its practicality with an implementation of a composite situation.

• 한국컴퓨터정보학회논문지
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• 제25권9호
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• pp.1-9
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• 2020

이 논문에서는 NoSQL 데이터베이스의 동작 과정에서 발생하는 라이브러리 콜과 관련 정보들을 기록하여 내부 동작 과정을 심층적으로 분석하는 방법을 제안한다. 이를 통해 지정한 라이브러리 콜을 관찰 및 기록하며, 기록된 라이브러리 콜 정보를 통해 NoSQL 데이터베이스 간 내부 동작 차이를 비교하고, 입력 데이터 개수의 변화에 따라 발생하는 라이브러리 콜의 변화를 관찰하여 각 데이터베이스의 특징 및 확장성을 평가한다. 컴퓨팅 성능의 발전과 빅테이터의 활성화에 따라 다양하고 많은 양의 데이터를 기록 및 분석하기 위한 여러 종류의 NoSQL 데이터베이스가 등장하였으며, 각 환경에 적합한 데이터베이스를 선택하기 위해 각 데이터베이스의 확장성을 평가할 필요가 있다. 그러나 벤치마크, 성능 모델을 통한 외부 동작 관찰 또는 설계에 따른 구조적 특징 분석과 같은 기존의 방식으로는 데이터베이스가 동작하는 과정을 분석 또는 예측하기 어렵다. 따라서, 더욱 심층적인 분석을 통해 동작 과정 및 확장성을 파악하는 본 논문에서 제안하는 기법의 활용이 필요하다.

• Journal of Communications and Networks
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• 제13권6호
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• pp.602-611
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• 2011

The inter-domain routing scalability issue is a major challenge facing the Internet. Recent wide deployments of multihoming and traffic engineering urge for solutions to this issue. So far, tunnel-based proposals and compact routing schemes have been suggested. An implicit assumption in the routing community is that structured address labels are crucial for routing scalability. This paper first systematically examines the properties of identifiers and address labels and their functional differences. It develops a simple Internet routing model and shows that a binary relation T defined on the address label set A determines the cardinality of the compact label set L. Furthermore, it is shown that routing schemes based on flat address labels are not scalable. This implies that routing scalability and routing stability are inherently related and must be considered together when a routing scheme is evaluated. Furthermore, a metric is defined to measure the efficiency of the address label coding. Simulations show that given a 3000-autonomous system (AS) topology, the required length of address labels in compact routing schemes is only 9.12 bits while the required length is 10.64 bits for the Internet protocol (IP) upper bound case. Simulations also show that the ${\alpha}$ values of the compact routing and IP routing schemes are 0.80 and 0.95, respectively, for a 3000-AS topology. This indicates that a compact routing scheme with necessary routing stability is desirable. It is also seen that using provider allocated IP addresses in multihomed stub ASs does not significantly reduce the global routing size of an IP routing system.

• 한국정보보호학회:학술대회논문집
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• 한국정보보호학회 2002년도 종합학술발표회논문집
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• pp.195-199
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• 2002

VPN(Virtual Private Networks)을 적절히 설계하기 위한 필요조건은 확장성, 효율성, 신뢰성, 관리의 용이성, 상호운용성과 보안이다. 이러한 요구사항들을 지원하기 위한 중요한 기술이 tunneling 이 될 것이다. 본 논문에서는 현재 주로 사용되고 있는 VPN tunneling 기술에 대해 조사하고 VPN에서 문제시되는 확장성과 Mobile VPN 환경에서 Mobile Station 의 자원제한을 고려한 VPN 서비스 모델을 제안한다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2010년도 추계학술대회
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• pp.188-191
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• 2010

The study investigated the optimal configuration of SVC (Scalable Video Coding) to apply to the satellite broadcasting service, and compared the performance of the SVC with that of the AVC (Advanced Video Coding). To get the optimal configuration, we analyzed the optimal bit rate allocation between the layers and the optimal scalability which requires the least bit rate for the required PSNR for various kinds of contents using JSVM. As a result of investigation, we found that the optimal bit rate allocation occurs when the bit rate of the base layer is minimum, and the spatial scalability shows the best performance. The performance of SVC is similar to that of AVC for spatial scalability, but it depends on contents.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권5호
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• pp.537-542
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• 2014

The three-dimensional (3-D) NAND flash structure with fully charge storage using edge fringing field effect is presented, and its programming characteristic is evaluated. We successfully confirmed that this structure using fringing field effect provides good program characteristics showing sufficient threshold voltage ($V_T$) margin by technology computer-aided design (TCAD) simulation. From the simulation results, we expect that program speed characteristics of proposed structure have competitive compared to other 3D NAND flash structure. Moreover, it is estimated that this structural feature using edge fringing field effect gives better design scalability compared to the conventional 3D NAND flash structures by scaling of the hole size for the vertical channel. As a result, the proposed structure is one of the candidates of Terabit 3D vertical NAND flash cell with lower bit cost and design scalability.

• Journal of Computing Science and Engineering
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• 제6권4호
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• pp.294-309
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• 2012

In the age of multi-core and specialized accelerators in high performance computing (HPC) systems, it is critical to understand application characteristics and apply suitable optimizations in order to fully utilize advanced computing system. Often time, the process involves multiple stages of application performance diagnosis and a trial-and-error type of approach for optimization. In this study, a general guideline of performance optimization has been demonstrated with two class-representing applications. The main focuses are on node-level optimization and inter-node scalability improvement. While the number of optimization case studies is somewhat limited in this paper, the result provides insights into the systematic approach in HPC applications performance engineering.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 춘계학술대회
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• pp.86-87
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• 2018

블록체인 기술은 여러 산업 분야에서 신뢰 모델과 비즈니스 프로세스를 혁신적으로 바꾸어 놓을 수 있는 잠재력이 있는 만큼, 응용 분야가 무궁무진할 것으로 예상된다. 그러나 이 기술은 아직까지 초기 단계에 있으며, 특히 블록의 증가에 따른 트랜잭션 데이터가 누적되면서 생기는 확장성이 심각한 문제로 부상하고 있다. 본 연구에서는 이러한 확장성 문제를 해결하는 현재까지 제시된 다양한 방법들에 대해 살펴보고 가능한 대안을 제시하고자 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권4호
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• pp.452-474
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• 2010

Formidable growth of Internet technologies has revealed challenging issues about its scale and performance evaluation. Modeling and simulation play a central role in the evaluation of the behavior and performance of the large-scale network systems. Large numbers of nodes affect simulation performance, simulation execution time and scalability in a weighty manner. Most of the existing simulators have numerous problems such as size, lack of system theoretic approach and complexity of modeled network. In this work, a scalable discrete-event modeling approach is described for studying networks' scalability and performance traits. Key fundamental attributes of Internet and its protocols are incorporated into a set of simulation models developed using the Discrete Event System Specification (DEVS) approach. Large-scale network models are simulated and evaluated to show the benefits of the developed network models and approaches.