• Journal of the Korea Society of Computer and Information
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• v.22 no.12
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• pp.87-93
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• 2017

The purpose of this study is to design and develop of digital contents to improve computational thinking in the online education environment. First, we planned the design and development of contents with 19 experts of Software education. Digital content was designed from the point of view of improving the educational quality and the quality of contents for the improve of computing thinking. The content type is classified into the SW education area; computer science, programming, physical computing, convergent computing, computing thinking, and software education that improves the computing thinking. And we designed 45 learning programs for each SW education area. Designed learning contents were developed in 464 lessons to suit the online education environment. The content validity of the proposed content was verified by the expert group and the average CVI value was over .83. Through this, we could analyze that the developed contents will help learners to expand their computing thinking.

• Journal of Computing Science and Engineering
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• v.7 no.1
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• pp.44-52
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• 2013

This paper addresses the problem of resource scheduling in a grid computing environment. One of the main goals of grid computing is to share system resources among geographically dispersed users, and schedule resource requests in an efficient manner. Grid computing resources are distributed, heterogeneous, dynamic, and autonomous, which makes resource scheduling a complex problem. This paper proposes a new approach to resource scheduling in grid computing environments, the hierarchical stochastic Petri net (HSPN). The HSPN optimizes grid resource sharing, by categorizing resource requests in three layers, where each layer has special functions for receiving subtasks from, and delivering data to, the layer above or below. We compare the HSPN performance with the Min-min and Max-min resource scheduling algorithms. Our results show that the HSPN performs better than Max-min, but slightly underperforms Min-min.

• The Journal of Information Systems
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• v.16 no.2
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• pp.69-91
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• 2007

The mobile computing environment has already matured and mobile services are activated throughout many industries. In the following years, these changes are expected to evolve into a ubiquitous computing environment. In the meantime, whether newly developed information technologies will thrive or diminished depends on user's intention to adopt them. Hence, the necessity of user-centered research considering ubiquitous computing in mobile computing environment is obvious. This study, thus, investigated ubiquitous factors in various literature related to ubiquitous computing and technology acceptance and it proposes a research model of the ubiquitous factors affecting user's intention to use mobile services, in terms of meaning(connectivity, mobility), service(contextual offer), compatibility(compatibility), and infrastructure(privacy, truth). The proposed model is expected to help both researchers and practitioners extend their understanding about the ubiquitous factors in mobile computing environment

• Journal of Information Processing Systems
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• v.12 no.3
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• pp.538-547
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• 2016

Cloud computing is a new style of computing in which dynamically scalable and reconfigurable resources are provided as a service over the internet. The MapReduce framework is currently the most dominant programming model in cloud computing. It is necessary to protect the integrity of MapReduce data processing services. Malicious workers, who can be divided into collusive workers and non-collusive workers, try to generate bad results in order to attack the cloud computing. So, figuring out how to efficiently detect the malicious workers has been very important, as existing solutions are not effective enough in defeating malicious behavior. In this paper, we propose a security protection framework to detect the malicious workers and ensure computation integrity in the map phase of MapReduce. Our simulation results show that our proposed security protection framework can efficiently detect both collusive and non-collusive workers and guarantee high computation accuracy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.5
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• pp.1998-2014
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• 2016

In recent years, cloud computing services based on smart phones and other mobile terminals have been a rapid development. Cloud computing has the advantages of mass storage capacity and high-speed computing power, and it can meet the needs of different types of users, and under the background, mobile cloud computing (MCC) is now booming. In this paper, we have put forward a new classification-based virtual machine placement (CBVMP) algorithm for MCC, and it aims at improving the efficiency of virtual machine (VM) allocation and the disequilibrium utilization of underlying physical resources in large cloud data center. By simulation experiments based on CloudSim cloud platform, the experimental results show that the new algorithm can improve the efficiency of the VM placement and the utilization rate of underlying physical resources.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.731-736
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• 2007

Ubiquitous computing is a model of computing in which computer functions are integrated into everyday life, providing services and information in anywhere and anytime fashion. Augmented Reality is one of ubiquitous computing technologies to provide new paradigm utilized to interact between human and computer. By adding computer-generated non-visual information to real information and their interaction. user can get the improved and more knowledgeable information about real world. The purpose of this paper is the integration of AR and knowledge-base reasoning technology in ubiquitous computing. Through the introduced concept, it is enable to provide adequate knowledge in the process of ship design and manufacturing easily (Knowledge Everywhere). That is, this is a basic research to construct knowledge-based ubiquitous environment (KAD/KAM) in shipbuilding industry.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.133-134
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• 2018

본 논문에서는 Edge Computing 알고리즘의 성능 분석 및 평가를 위해 SDN 무선 테스트베드를 구현하는 방안을 제안한다. Edge Computing 환경은 수 많은 노드를 연결해 테스트해야 하며, 따라서 무선 테스트베드가 적합하다. Edge Computing 기술이 발전함에 따라 네트워크가 점점 더 복잡해지고 정확하고 확장 가능한 테스트베드 기술에 대한 필요성이 급증하고 있다. 네트워크 연구를 위해 대규모 테스트 베드가 필수적이다. 본 논문에서는 Raspberry-Pi를 이용해 Wireless SDN 테스트베드 구축 방안에 대해 소개하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.70-71
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• 2017

Volunteer Computing은 대규모 프로젝트를 많은 분산된 데스크탑, 랩탑 PC, 그리고 스마트 폰과 같은 모바일 디바이스의 idle(유휴 상태)인 컴퓨팅 자원을 기여(Volunteer)받아 수행하는 환경이다. 그러나 기여된 컴퓨팅 자원이 idle과 used(사용 상태) 간의 상태전이가 빈번히 일어나거나, idle로 지속되는 시간이 짧은 자원의 경우, 프로젝트를 수행하는데 비효율적이다. 따라서 본 논문에서는 이러한 자원을 구분하고, 해당 자원의 다음 상태전이확률테이블을 계산하여 결과에 따라 해당 자원에 적합한 작업을 할당하는 방법을 제안한다.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1547-1550
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• 2002

Reconfigurable computing is a new computing paradigm which has more potential in terms of performance and flexibility. Reconfigurable computing systems are opening a new era in digital signal processing such as multimedia, communication and consumer electronics because they can filter data rapidly and excel at pattern recognition, image process- ing and encryption. Although many reconfigurable computing systems use a conventional programmable device, they carry several serious problems to be solved. This paper proposes a logic block architecture of programmable device suit-able for the reconfigurable computing. Compared to conventional logic blocks, our logic block can improve implementation density, efficiency and speed.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.612-614
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• 1998

As chip feature size decrease, interconnect delay gains more importance. A accurate timing analysis required to estimate interconnect delay as well as cell delay. In this paper, we present a timing-level delay calculation tool of which the accuracy is bounded within 10% of SPICE results. This delay calculation tool generates delay values in SDF(Standard Delay Format) for parasitic data extracted in SPEF(Standard Parasitic Exchange Format). The efficiency of the tool is easily seen because it uses AWE(Asymptotic Waveform Evaluation) algorithm for interconnect delay calculation, and precharacterized library and effective capacitance model for cell delay calculation.