• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.250-253
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• 2011

Chip manufacture nowadays turned their attention from accelerating uniprocessors to integrating multiple cores on a chip. Moreover desktop graphic hardware is now starting to support general purpose computation. Desktop users are able to use multi-core CPU and GPU as a high performance computing resources these days. However exploiting parallel computing resources are still challenging because of lack of higher programming abstraction for parallel programming. The 2-dimensional discrete cosine transform (2D-DCT) algorithms are most computational intensive part of JPEG encoding. There are many fast 2D-DCT algorithms already studied. We implemented several algorithms and estimated its runtime on multi-core CPU and GPU environments. Experiments show that data parallelism can be fully exploited on CPU and GPU architecture. We expect parallelized DCT bring performance benefit towards its applications such as JPEG and MPEG.

• International Journal of Computer Science & Network Security
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• v.23 no.5
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• pp.65-72
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• 2023

Cloud Computing is one of the current research areas in computer science. Recently, Cloud is the buzz word used everywhere in IT industries; It introduced the notion of 'pay as you use' and revolutionized developments in IT. The rapid growth of modernized cloud computing leads to 24×7 accessing of e-resources from anywhere at any time. It offers storage as a service where users' data can be stored on a cloud which is managed by a third party who is called Cloud Service Provider (CSP). Since users' data are managed by a third party, it must be encrypted ensuring confidentiality and privacy of the data. There are different types of cryptographic algorithms used for cloud security; in this article, the algorithms and their security measures are discussed.

• The Journal of Korean Association of Computer Education
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• v.11 no.4
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• pp.23-36
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• 2008

It's known by recent surveys that many students have difficulty in understanding the concepts of programming algorithms, and don't feel interested in learning them. Dynamic programming, one of the most important and widely-used algorithms in computer science, is especially feared by students and unlike other algorithms, it also requires understanding of the process of problem solving and storage space design as well as basic principles of the algorithm. And so it has not been properly covered in classes. In this paper, we developed a visual simulator to solve the above problems in learning dynamic programming. This learning simulator is designed for students to run the algorithms themselves and learn how it works by visualizing each step of dynamic programming and corresponding states of storage space.

• The Journal of Korean Association of Computer Education
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• v.14 no.5
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• pp.1-8
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• 2011

The purpose of this study is to explore vocational high school students' understanding levels and misconceptions regarding the time-efficiency of algorithms. In this study, a questionnaire with nine questions was developed. The questionnaire is base on three misconceptions about the time-efficiency of algorithms that are examined through prior studies. The questionnaire was applied to 51 students who completed a programming course. The result shows that the students didn't sufficiently understand the concept of time-efficiency of algorithms and several common misconceptions appeared repeatedly. Finally, teaching strategies using simulation and assesment framework for algorithm's time-efficiency were presented and some recommendations were suggested for refining the curriculum relating computer programming and algorithms.

• Journal of Communications and Networks
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• v.6 no.1
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• pp.46-59
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• 2004

In this paper, we present two algorithms for efficiently aggregating link state information needed for quality-of-service (QoS) routing. In these algorithms, each edge node in a group is mapped onto a node of a shufflenet or a node of a de Bruijn graph. By this mapping, the number of links for which state information is maintained becomes aN (a is an integer, N is the number of edge nodes) which is significantly smaller than N2 in the full-mesh approach. Our algorithms also can support asymmetric link state parameters which are common in practice, while many previous algorithms such as the spanning tree approach can be applied only to networks with symmetric link state parameters. Experimental results show that the performance of our shufflenet algorithm is close to that of the full-mesh approach in terms of the accuracy of bandwidth and delay information, with only a much smaller amount of information. On the other hand, although it is not as good as the shufflenet approach, the de Bruijn algorithm also performs far better than the star approach which is one of the most widely accepted schemes. The de Bruijn algorithm needs smaller computational complexity than most previous algorithms for asymmetric networks, including the shufflenet algorithm.

• Industrial Engineering and Management Systems
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• v.11 no.1
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• pp.123-132
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• 2012

Recently, global environmental problems have become serious due to human economic activities. Therefore, in order to build a sustainable society in which human economic activities coexist with nature, it is important to promote and enhance environmental education. As a preceding study, a board and computer game of "Ecopoly," which is the game for education on global environmental problems, were developed. This study further aims to develop algorithms which make decisions in Ecopoly, to automate decision-makings of opponents using the algorithms, and to develop the environmental educational game "Ecopoly V" which enables self-learning. In order to develop the algorithms, the board game of Ecopoly was played, and each player's decision-makings at the all points at which players make a decision were observed and analyzed. From the analyses, it became clear that the decision-makings were distinguished by 3 characteristics; Ecology type, Economy type, and Balance type. Based on the characteristics, the factors and standard values of each decision-making were made clear. Algorithms were developed based on the factors and standard values. Ecopoly V was developed by incorporating the algorithms into the computer game of Ecopoly. Experimental testing of the game was conducted and the validity of the game was verified.

• Journal of The Korean Association of Information Education
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• v.22 no.6
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• pp.671-679
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• 2018

Sorting algorithms are the basic building blocks that computer science students need to learn. In recent years, sorting algorithms also have begun to be taught in K-12 classrooms using "the educational sorting game" described in CSUnplugged. However, although the educational sorting game was developed for students aged 8 and up, it is hard for K-12 teachers to play with their students because it is difficult for teachers to understand all of the algorithms and some popular algorithms do not work well in the educational sorting game. In this paper, we discuss what teachers should know, and experimentally analyze the performance of the existing algorithms when applied to the educational sorting game.

• International Journal of Computer Science & Network Security
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• v.23 no.8
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• pp.204-209
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• 2023

Dynamic Bandwidth Allocation (DBA) methods in telecommunication network & systems have emerged with mechanisms for sharing limited resources in a rapidly growing number of users in today's access networks. Since the DBA research trends are incredibly fast-changing literature where almost every day new areas and terms continue to emerge. Co - citation analysis offers a significant support to researchers to distinguish intellectual bases and potentially leading edges of a specific field. We present the visualization based analysis for DBA algorithms in telecommunication field using mainstream co-citation analysis tool-CiteSpace and web of science (WoS) analysis. Research records for the period of decade (2009-2018) for this analysis are sought from WoS. The visualization results identify the most influential DBA algorithms research studies, journals, major countries, institutions, and researchers, and indicate the intellectual bases and focus entirely on DBA algorithms in the literature, offering guidance to interested researchers on more study of DBA algorithms.

• Journal of the Korea Society of Computer and Information
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• v.28 no.4
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• pp.1-11
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• 2023

In this paper, instead of using recurrent neural network, we compare a classification performance of time series imaging algorithms using convolution neural network. There are traditional algorithms that imaging time series data (e.g. GAF(Gramian Angular Field), MTF(Markov Transition Field), RP(Recurrence Plot)) in TSC(Time Series Classification) community. Furthermore, we compare STFT(Short Time Fourier Transform) algorithm that can acquire spectrogram that visualize feature of voice data. We experiment CNN's performance by adjusting hyper parameters of imaging algorithms. When evaluate with GunPoint dataset in UCR archive, STFT(Short-Time Fourier transform) has higher accuracy than other algorithms. GAF has 98~99% accuracy either, but there is a disadvantage that size of image is massive.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1999-2005
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• 2005

Collaboration in wireless sensor networks must be fault-tolerant due to the harsh environmental conditions in which such networks can be deployed. This paper focuses on finding signal processing algorithms for collaborative target detection based on the generalized approach to signal processing in the presence of noise that are efficient in terms of communication cost, precision, accuracy, and number of faulty sensors tolerable in the wireless sensor network. Two algorithms, namely, value fusion and decision fusion constructed according to the generalized approach to signal processing in the presence of noise, are identified first. When comparing their performance and communication overhead, decision fusion is found to become superior to value fusion as the ratio of faulty sensors to fault free sensors increases. The use of the generalized approach to signal processing in the presence of noise under designing value and decision fusion algorithms in wireless sensor networks allows us to obtain the same performance, but at low values of signal energy, as under the employment of universally adopted signal processing algorithms widely used in practice.