• Journal of Satellite, Information and Communications
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• v.11 no.4
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• pp.102-106
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• 2016

With the popularity of smart phones and the help of high-speed wireless communication technology, high-quality multimedia contents have become common in mobile devices. Especially, the release of Oculus Rift opens a new era of virtual reality technology in consumer market. At the same time, 3D audio technology which is currently used to make computer games more realistic will soon be applied to the next generation of mobile phone and expected to offer a more expansive experience than its visual counterpart. This paper surveys concepts, algorithms, and systems for modeling 3D sound virtual environment applications. To do this, we first introduce an important design principle for audio rendering based on physics-based geometric algorithms and multichannel technologies, and introduce an audio rendering pipeline to a scene graph-based virtual reality system and a hardware architecture to model sound propagation.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.1
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• pp.67-71
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• 2009

Recently, the string non-inclusion related problems have been studied vigorously. Given a set of strings F over a constant size alphabet, consider a string x such that x does not include any string in F as a substring. We call x a Common Non-SuperString(CNSS for short) of F. Among the CNSS's of F, the longest one with finite length is called the Longest Common Non-SuperString(LCNSS for short) of F. In this paper, we first propose a new graph model using prefixes of F. Next, we suggest an O(N)-time algorithm for finding the LCNSS of F, where N is the sum of the lengths of all the strings in F.

• The KIPS Transactions:PartD
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• v.14D no.3 s.113
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• pp.347-354
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• 2007

It is not easy for the customers to search the valuable information on the goods among countless items available in the Internet. In order to save time and efforts in searching the goods the customers want, it is very important for a recommender system to have a capability to predict accurately customers' preferences. In this paper we present a refined neighbor selection algorithm for clustering based collaborative filtering in recommender systems. The algorithm exploits a graph approach and searches more efficiently for set of influential customers with respect to a given customer; it searches with concepts of weighted similarity and ranked clustering. The experimental results show that the recommender systems using the proposed method find the proper neighbors and give a good prediction quality.

• The KIPS Transactions:PartB
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• v.16B no.5
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• pp.377-384
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• 2009

A new algorithm in order to classify various contents in the image documents, such as text, figure, graph, table, etc. is proposed in this paper by classifying contents using texture-based PCA, and by segmenting document images using local entropy-based histogram. Local entropy and histogram made the binarization of image document not only robust to various transformation and noise, but also easy and less time-consuming. And texture-based PCA algorithm for each segmented region was taken notice of each content in the image documents having different texture information. Through this, it was not necessary to establish any pre-defined structural information, and advantages were found from the fact of fast and efficient classification. The result demonstrated that the proposed method had shown better performances of segmentation and classification for various images, and is also found superior to previous methods by its efficiency.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.2
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• pp.55-64
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• 2000

In this paper, we propose an efficient datapath placement algorithm to minimize track density. Here, we consider each datapath element as a cluster, and merge the most strongly connected two clusters to a new cluster until only one cluster remains. As nodes in the two clusters to be merged are already linearly ordered respectively, we can merge two clusters with connecting them. The proposed algorithm produces circular linear ordering by connecting starting point and end point of the final cluster, and n different linear ordering by cutting between two contiguous elements of the circular linear ordering. Among the n different linear ordering, the linear ordering to minimize track density is final solution. In this paper, we show and utilize that if two clusters are strongly connected in a graph, the inner product of the corresponding vectors mapped in d-dimensional space using spectral method is maximum. Compared with previous datapath placement algorithm GA/S $A^{［2］}$, the proposed algorithm gives similar results with much less computation time.

• Journal of the Korea Society of Computer and Information
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• v.19 no.7
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• pp.131-140
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• 2014

In this paper, we present an efficient implementation of Kruskal's algorithm to obtain a minimum spanning tree. The proposed method utilizes the union-find data structure, reducing the depth of the tree of the node set by making the nodes in the path to root be the child node of the root of combined tree. This method can reduce the depth of the tree by shortening the path to the root and lowering the level of the node. This is an efficient method because if the tree's depth reduces, it could shorten the time of finding the root of the tree to which the node belongs. The performance of the proposed method is evaluated through the graphs generated randomly. The results showed that the proposed method outperformed the conventional method in terms of the depth of the tree.

• Journal of IKEEE
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• v.5 no.2 s.9
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• pp.190-200
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• 2001

This paper is addressed to welding defect feature vector selection and implementation method of welding defect classifier using fuzzy techniques. We compare IAV, zero-crossing number as time domain analysis, power spectrum coefficient as frequency domain, histogram as both domain for welding defect feature selection. We choose histogram as feature vector by graph analysis and find out that maximum frequent occurrence number and section of corresponding signal scale in relative histogram show obvious difference between normal welding and voiding with penetration depth defect. We implement a fuzzy welding defect classifier using these feature vector, test it to verify its effectiveness for 695 welding data frame which consist of 4000 sampled data. As result of test, correct classification rate is 92.96%. Lab experimental results show a effectiveness of fuzzy welding defect classifier using relative histogram for practical Laser welding monitoring system in industry.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.955-969
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• 2019

Analyzing on-line consumer responses is directly related to the management performance of food companies. Therefore, this study collected and analyzed data from an on-line portal site created by consumers about food companies with issues and examined the relationships between the data and the management performance. Through this process, we identified consumers' awareness of these companies obtained from big data analysis and analyzed the relationship between the results and the sales and stock prices of the companies through a time-series graph and correlation analysis. The results of this study were as follows. First, the result of the text mining analysis suggests that consumers respond more sensitively to negative issues than to positive issues. Second, the emotional analysis showed that companies' ethics issues (Enterprise 3 and 4) have a higher level of emotional continuity than that of food safety issues. It can be interpreted that the problem of ethical management has great influence on consumers' purchasing behavior. Finally, In the case of all negative food issues, the number of word frequency and emotional scores showed opposite trends. As a result of the correlation analysis, there was a correlation between word frequency and stock price in the case of all negative food issues and also between emotional scores and stock price. Recently, studies using big data analytics have been conducted in various fields. Therefore, based on this research, it is expected that studies using big data analytics will be done in the agricultural field.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.413-421
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• 2005

Intra-block remarshalling is the task of rearranging into some target bays those containers which are scattered within around the block. If multiple transfer cranes installed in the block are all used together we may be able to complete the remarshalling task as early as possible. However, when multiple cranes are used simultaneously, there may occur significant delays if we do not carefully consider interferences between the cranes at the time of scheduling. Especially, delays caused by interferences occur more frequently in case of using non-crossing cranes. This paper presents an efficient heuristics method for assigning moves of containers to each crane and for determining an appropriate container moving order in a manner sensitive to the interferences. Simulation experiments have shown that the proposed method can effectively reduce delays in various environments.

• Korean Journal of Oriental Medicine
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• v.14 no.3
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• pp.113-119
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• 2008

In pulse diagnosis, the indentation pressure is one of the most important factors as well as the change of pulse shape and the distribution of pressure via time. But, on the oriental medical doctor's indentation pressure control, the understandings of the neurophysiological meanings and mechanisms have been lacked. So, in this paper, we considered on these issues and then proposed a proper system which can imitate the OMD's indentation pressure control mechanisms. As a result, both tactile information and kinesthetic information were found to be essential to the indentation pressure control so that a system, which can measure both the physical indent pressure and the displacement of an indentation arm, has been proposed. With this proposed system, while the indentation was being controlled through the moving step number of the step motor, the physical indentation pres sure and displacement of the indentation arm were measured. From these measured data, the relationships between the moving step number and both physical indentation pressure and displacement were revealed to have linear characteristics in early phase and to have nonlinear characteristics in latter phase. Additionally, three types of graph were generated whose X axis means the moving step number, the physical indentation pressure and the displacement respectively and Y axis means the pulse pressure. By comparing these graphs, we come to conclude that different concepts on indentation pressure control cause different diagnostic results on floating/sinking degrees for the same subject. Consequently, an indentation system for the pulse diagnosis should be able to provide both the tactile information and kinesthetic information, that is, the physical indentation pressure and the displacement of the indentation arm. In future, the proposed system should be optimized to the pulse diagnosis environment and how to combine the both information for more reliable diagnosis should be studied.