• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.5
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• pp.1087-1096
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• 2011

Vehicular Ad Hoc Network(VANET) using wireless network is offering the communications between vehicle and vehicle(V2V) or vehicle and infrastructure(V2I). VANET is being actively researched from industry field and university because of the rapid developments of the industry and vehicular automation. Information, collected from VANET, of velocity, acceleration, condition of road and environments provides various services related with safe drive to the drivers, so security over network is the inevitable factor. For the secure message authentication, a number of authentication proposals have been proposed. Among of them, a scheme, proposed by Jung, applying database search algorithm, Bloom filter, to RAISE scheme, is efficient authentication algorithm in a dense space. However, k-anonymity used for obtaining the accurate vehicular identification in the paper has a weak point. Whenever requesting the righteous identification, all hash value of messages are calculated. For this reason, as the number of car increases, a amount of hash operation increases exponentially. Moreover the paper does not provide a complete key exchange algorithm while the hand-over operation. In this paper, we use a Received Signal Strength Indicator(RSSI) based velocity and distance estimation algorithm to localize the identification and provide the secure and efficient algorithm in which the problem of hand-over algorithm is corrected.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.5
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• pp.471-479
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• 2009

In this paper, we proposed an improved ray tracing method with an amelioration of visible tree structure, a visible face determination method, and non-uniform random test point method. In a proposed visible tree structure, it reduces tree nodes by means of merging similar nodes. In a visible face determination method, it shows that a ray hit test with a packet ray method can reduce a test time. A ray tracing method involving with a packet ray hit test method can improve a tree construction time up to 3.3 times than a ray tracing method with a single ray hit test method. Furthermore, by seeding a non-uniform and random test point on a face, tree construction time is improved up to 1.11 times. Received powers from the proposed ray tracing results and measured results have good agreement with 1.9 dB RMS error.

• Journal of Digital Contents Society
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• v.12 no.2
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• pp.217-223
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• 2011

AI(Artificial Intelligence) refers to the area of computer engineering and IT technology that focuses on the methodology and creation of intelligent agents. The Othello game is often produced with AI, since it is played with relatively simple rules on a board and on a limited space of 8 rows and 8 columns. Previous algorithms take longer time than desirable and often fail to face new circumstances, as they search for all the possible cases and rules. In order to solve this crucial weakness, we propose that a CBR algorithm be applied to Orthello. Case-Based Reasoning(CBR), is the process of solving new problems based on the solutions of the past similar problems. We can apply this process to Othello and expedite the process of computer reasoning for a solution to new cases based on the data from accumulated past cases. Then, these new solutions are dynamically added to the set of past cases so that it becomes harder for players(users) to be able to read the pattern. The proposed system in which a CBR algorithm is applied to the Othello game makes the computation process faster and the game harder to play.

• Journal of Digital Convergence
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• v.10 no.6
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• pp.1-6
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• 2012

In modern society, the amount of information has been significantly increased according to the development of IT convergence technology. That leads to develop information obtaining and searching technologies from lots of data. However, they don't seem to have been actually effective for users' health care and promotion not only for limitations of Web-based information and but for lack of personalization. Health information support services have been generally developed in a format of inputting data on bio-information acquired into the computer for the existing network-based transmission. In this paper, a life habits disease system that uses the existing medical data and Framingham risk factor(FRS) performs neural network is proposed. Based on the proposed system, it is possible to provide the fundamental data and guideline to doctors for recognizing the life habits disease diagnosis of patients and that represents increases in the welfare of patients.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.6
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• pp.137-145
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• 2010

Digital vessel have to accurate and efficient mange the digital data from various sensors in the digital vessel. But, In sensor network, it is difficult to transmit and analyze the entire stream data depending on limited networks, power and processor. Therefore it is suitable to use alternative stream data processing after classifying the continuous stream data. In this paper, We propose efficient processing method that arrange some sensors (temperature, humidity, lighting, voice) and process query based on sliding window for efficient input stream and pre-clustering using multiple Support Vector Machine(SVM) algorithm and manage hash table to summarized information. Processing performance improve as store and search and memory using hash table and usage reduced so maintain hash table in memory. We obtained to efficient result that accuracy rate and processing performance of proposal method using 35,912 data sets.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1183-1190
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• 2017

With the development of network and IT technology, people are searching and purchasing items they want, not bounded by places. Therefore, there are various studies on how to solve the scalability problem due to the rapidly increasing data in the recommendation system. In this paper, we propose an item-based collaborative filtering method using Tag weight and a recommendation technique using MapReduce method, which is a distributed parallel processing method. In order to improve speed and efficiency, the proposed method classifies items into categories in the preprocessing and groups according to the number of nodes. In each distributed node, data is processed by going through Map-Reduce step 4 times. In order to recommend better items to users, item tag weight is used in the similarity calculation. The experiment result indicated that the proposed method has been more enhanced the appropriacy compared to item-based method, and run efficiently on the large amounts of data.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.326-331
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• 2008

We present the seamless browsing - a new Zooming technique based on the zoom ratios and the distances of the hyperlinks from the pointer. In most cases, users have to activate the interesting link after guessing the target content of it, just based on the insufficient information from the link label or title. We propose that a web browser displays a limited number of hyperlinks in an area around the pointer in a distinguished way, e.g. in different sizes of thumbnails, transparency or style. If a user zooms in on the pointer area, to new web browser displays the varying images of hyperlink-targets according to the zoom ratio, and finally it transfers to the new target page which was nearest to the pointer position. This method allows users to easily select a hyperlink based on rich information given by zoomable thumbnails and seamlessly to transit through web pages just with zooming. 1n our experiments, results show that the seamless browsing significantly outperforms the legacy way.

• Journal of Korea Spatial Information System Society
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• v.5 no.1 s.9
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• pp.65-74
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• 2003

Location-based service is an important spatiotemporal database application area that provides the location-aware information of wireless terminals via positioning devices such as GPS. With the rapid advances of wireless communication systems, the requirement of mobile application areas including traffic, mobile commerce and supply chaining management became the center of attention for various research issues in spatiotemporal databases. In this paper we present the A-Quadtree, an efficient indexing method for answering location-based queries where the movement vector information (e.g., speed and velocity) is not presented. We implement the A-Quadtree with an index structure for object identifiers as a.Net component to apply the component to multiplatforms. We present our approach and describe the performance evaluation through various experiments. In our experiments, we compare the performance with previous approaches and show the enhanced efficiency of our method.

• Korean Journal of Microbiology
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• v.32 no.3
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• pp.232-237
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• 1994

Microorganism producing glutaryl 7-aminodeacetoxycephalosporanic acid (GL-7-ADCA) acylase was screened from soil. The microorganism was identified as Alcaligenes sp. J-421 by its morphology and biochemical properties. Cultural conditions of Alcaligenes sp. J-421 were investigated for the production of GL-7-ADCA acylase. Optimum medium composition was 1% glucose, 1% beef extract, 0.5% yeast extract, 0.2% monosodium L-glutamate, 0.1% glutaric acid, 0.2% NaCl, 0.5% $K_2$ $HPO_4$, and 0.05% $CuSO _4{\cdot}5H_2O$. Optimum cultivation conditions for the production of the enzyme in 5 l jar fermentor were $37^{\circ}C$, tip speed 300 rpm, aeration 1 vvm. Optimum reaction pH of the enzyme was 8.0 and the enzyme was stable at pH7.0-11.0.

• Journal of Applied Biological Chemistry
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• v.53 no.3
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• pp.179-183
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• 2010

To produce the functional food materials from edible mushrooms, hot-water extracts from 70 kinds of mushroom mycelia were examined for anti-complementary activity and Phellinus linteus showed the highest activity through the complement fIxation test. The maximum production of Phellinus linteus mycelia with anti-complementary activity was observed in culture medium containing soluble starch 3.0%, peptone 0.3%, yeast extract 0.4%, $MgSO_4{\cdot}7H_2O$ 0.1%, $K_2HPO_4$ 0.2% and in the culture conditions controlled at initial pH 7.0, $30^{\circ}C$ and 150 rpm by the rotary shaker. In addition, the maximum production of mycelial dry weight was 15 mg/mL after 18 days under the optimal conditions, and anti-complementary activity was reached to 88% in 5 L-jar fermenter.