• The KIPS Transactions:PartD
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• v.13D no.3 s.106
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• pp.357-368
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• 2006

This paper discusses the way of processing time-series subsequence matching under time warping. Time warping enables finding sequences with similar patterns even when they are of different lengths. The prefix-querying method is the first index-based approach that performs time-series subsequence matching under time warping without false dismissals. This method employs the $L_{\infty}$ as a base distance function for allowing users to issue queries conveniently. In this paper, we extend the prefix-querying method for absorbing $L_1$, which is the most-widely used as a base distance function in time-series subsequence matching under time warping, instead of $L_{\infty}$. We also formally prove that the proposed method does not incur any false dismissals in the subsequence matching. To show the superiority of our method, we conduct performance evaluation via a variety of experiments. The results reveal that our method achieves significant performance improvement in orders of magnitude compared with previous methods.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.9
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• pp.898-903
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• 2010

Popularity of smartphones such as Google Android phones and Apple iphones, is increasing the demand on more reliable high performance file system for flash memory. In this paper, we propose two techniques to improve the performance of YAFFS (Yet Another Flash File System), while enhancing the reliability of the system. Specifically, we first propose to manage metadata and user data separately on segregated blocks and indexing information piggy-back technique for reducing mount time and also enhancing performance. Second, we tailor the wear-leveling to the segregated metadata and user data blocks. Performance evaluation results based on real hardware system with 1GB NAND flash memory show that the YAFFS with our proposed techniques realized outperforms the original YAFFS by six times in terms of mount speed and five times in terms of benchmark performance, while reducing the average erase count of blocks by 14%.

• Journal of the Korea Society of Computer and Information
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• v.17 no.2
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• pp.167-176
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• 2012

In this paper we design and implement a new Hybrid Equipment Data Acquisition System (HEDAS) for data collection of semiconductor and optoelectronic manufacturing equipments in the equipment engineering system(EES) framework. The amount of the data collected from equipments have increased rapidly in equipment engineering system. The proposed HEDAS efficiently handles a large amount of real-time equipment data generated from EES framework. It also can support the real-time ESS applications as well as non real-time ESS applications. For the real-time EES applications, it performs high-speed real-time processing that uses continuous query and filtering techniques based on memory buffers. The HEDAS can optionally store non real-time equipment data using a HEDAS-based database or a traditional DBMS-based database. In particular, The proposed HEDAS offers the compression indexing based on the timestamp of data and query processing technique saving the cost of disks storage against extremely increasing equipment data. The HEDAS is efficient system to collect huge real-time and non real-time equipment data and transmit the collected equipment data to several EES applications in EES framework.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.1
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• pp.85-91
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• 2011

The technique, which is able to detect and recognize characters in videos such as a movie or TV drama, can be used for applications which are database management of a general user's facial images for the suppliers of PVR(personal video recorder), mobile phones, and multimedia, etc. In this paper, we propose a face detection algorithm. It searches the character through cast indexing when the scene is changed in video. It is consisted of three stages. The first step is the detection-step of the scene change after producing a paused image. The second step is the face detection-step using color information. The final step is the detection-step which detects its features by the facial boundary. According to the experimental result, it has detected faces in different conditions successfully and more advanced than the existing other one that are using only color information.

• Journal of Biosystems Engineering
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• v.21 no.3
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• pp.325-335
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• 1996

Visual features are crucial for monitoring the growth state, indexing the drying performance, and grading the quality of oak mushrooms. A computer vision system with neural net information processing technique was utilized to quantize quality factors of a dried oak mushrooms distributed over the cap and gill sides. In this paper, visual feature extraction algorithm were integrated with the neural net processing to deal with various fuzzy patterns of mushroom shapes and to compensate the fault sensitiveness of the crisp criteria and heuristic rules derived from the image processing results. The proposed algorithm improved the segmentation of the skin features of each side, the identification of cap and gill surfaces, the identification of stipe states and removal of the stipe, etc. And the visual characteristics of dried oak mushrooms were analyzed and primary visual features essential to tile quality evaluation were extracted and quantized. In this study, black and white gray images were captured and used for the algorithm development.

• International Journal of Knowledge Content Development & Technology
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• v.12 no.1
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• pp.17-34
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• 2022

This informetrics study was conducted to find out the distribution of articles and authors that published in African Journal of Library, Archives and Information Studies [AJLAIS]) from 2009 to 2018; considering the year-wise growth of research articles; authorship pattern and collaboration ratio; subject and geographical distributions of authors; and authors' productivity level. A descriptive informetrics research design was adopted. Quota sampling technique was used to select all the articles published within the ten-year period. Data collected through a self-designed checklist was analyzed using frequency count and percentage. The findings revealed that 141 articles, contributed by 266 authors were published by AJLAIS during the period. An annual average growth of 1.20% was recorded. Overall year-wise authorship pattern revealed that majority of articles (62.41%) published in AJLAIS were multiple authored. Also, articles on Informetrics and ICT dominated the journal. Some subject areas not covered were identified such as: indexing and serial collections management. Average collaborative index across the 10-year period for the journal was 0.62. South Africa and Nigeria were the two major prolific contributors to AJLAIS, just as evidence-based research papers of survey type (65.25%) were the most common to the journal. There should be increased numbers of articles in each edition over the coming years, and awareness should be created by the publishers to familiarize the researchers with the publishing requirements of the journal. Also, LIS researchers should concentrate more on areas usually left untouched by previous studies. The study is original as no other similar study was found on publication pattern of articles in AJLAIS covering a ten year period of 2009-2018. The findings of the study will also serve as a feedback mechanism for the Publisher of the Journal and LIS researchers on how to improve the journal and LIS research in general.

• The KIPS Transactions:PartD
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• v.14D no.3 s.113
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• pp.355-362
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• 2007

With development of mobile communications terminal and expansion of mobile Internet, a large number of users can use mobile web contents at anytime and anywhere and will demand service of greater contents. Due to such demand, many studies are being carried out on transcoding contents so that wired web contents can be used in mobile web. However, transcoding and creation of mobile web contents involve difficulties because specifications available from telecommunications companies and mobile terminals have not been standardized. Especially, in order for serving dynamic object of wired web page contents to dynamically change according to time or user, it is required not only to program scripts to suit each terminal, but also to transcode the resources used in advance. for solution to this problem, this study uses the hierarchy structure of DOM (document object model) to display structural characteristics of wired web page. In other words, this study proposes the following technique. Wired web pages are analyzed and the results are established as data structure. Then, dynamic object is extracted and the domain is indexed so that, when serving mobile web page, information can be extracted at the indexed position to create mobile web contents for service on real-time basis. Also, this study aims at developing an editing device to edit mobile web contents and mobile web service server to service the edited contents by applying the above technique.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.3
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• pp.319-332
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• 2004

Due to their high strength to weight ratios and excellent durability, fiber reinforced polymer(FRP) is widely used in construction industries. In this paper, a shape optimum design of FRP bridge decks haying pultruded cellular cross-section is presented. In the problem formulation, an objective function is selected to minimize the volumes. The cross-sectional dimensions and material properties of the deck of FRP bridges are used as the design variables. On the other hand, deflection limits in the design code, material failure criteria, buckling load, minimum height, and stress are selected as the design constraints to enhance the structural performance of FRP decks. In order to efficiently treat the optimization process, the cross-sectional shape of bridge decks is assumed to be a tube shape. The optimization process utilizes an improved Genetic Algorithms incorporating indexing technique. For the structural analysis using a three-dimensional finite element, a commercial package(ABAQUS) is used. Using a computer program coded for this study, an example problem is solved and the results are presented with sensitivity analysis. The bridge consists of a deck width of 12.14m and is supported by five 40m long steel girders spaced at 2.5m. The bridge is designed to carry a standard DB-24 truck loading according to the Standard Specifications for Highway Bridges in Korea. Based on the optimum design, viable cross-sectional dimensions for FRP decks, suitable for pultrusion process are proposed.

• Journal of Korea Multimedia Society
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• v.13 no.5
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• pp.663-673
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• 2010

As a tool used for video maintenance, Video segmentation divides videos in hierarchical and structural manner. This technique can be considered as a core technique that can be applied commonly for various applications such as indexing, abstraction or retrieval. Conventional video segmentation used adaptive threshold to split video by calculating difference between consecutive frames and threshold value in window with fixed size. In this case, if the time difference between occurrences of cuts is less than the size of a window or there is much difference in neighbor feature, accurate detection is impossible. In this paper, Improved Adaptive threshold algorithm which enables determination of window size according to video format and reacts sensitively on change in neighbor feature is proposed to solve the problems above. Post-Processing method for decrement in error caused by camera flash and fast movement of large objects is applied. Evaluation result showed that there is 3.7% improvement in performance of detection compared to conventional method. In case of application of this method on modified video, the result showed 95.5% of reproducibility. Therefore, the proposed method is more accurated compared to conventional method and having reproducibility even in case of various modification of videos, it is applicable in various area as a video maintenance tool.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.648-653
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• 2008

With development of mobile communications terminal and expansion of mobile Internet, a large number of users can use mobile web contents at anytime and anywhere and will demand service of greater contents. Due to such demand, many studies are being carried out on transcoding contents so that wired web contents can be used in mobile web. However, transcoding and creation of mobile web contents involve difficulties because specifications available from telecommunications companies and mobile terminals have not been standardized. Especially, in order for serving dynamic object of wired web page contents to dynamically change according to time or user, it is required not only to program scripts to suit each terminal, but also to transcode the resources used in advance. For solution to this problem, this study uses the hierarchy structure of DOM (document object model) to display structural characteristics of wired web page. In other words, this study proposes the following technique Wired web pages are analyzed and the results are established as data structure. Then, dynamic object is extracted and the domain is indexed so that, when serving mobile web page, information can be extracted at the indexed position to create mobile web contents for service on real-time basis.