• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.5
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• pp.601-608
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• 2014

In this study we propose an image denoising algorithm appropriate for mobile smart phone equipped with limited computing ability, which has better performance and at the same time comparable quality comparing with previous studies. The proposed image denoising algorithm for mobile smart phone cameras in low level light environment reduces computational complexity and also prevents edge smoothing by extracting just Gaussian noises from the noisy input image. According to the experiment result, we verified that our algorithm has much better PSNR value than methods applying mean filter or median filter. Also the result image from our algorithm has better clear quality since it preserves edges while smoothing input image. Moreover, the suggested algorithm reduces computational complexity about 52% compared to the method applying original Laplacian mask computation, and we verified that our algorithm has good denoising quality by implementing the algorithm in Android smart phone.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.1
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• pp.55-61
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• 2010

An impact bending test method was used to evaluate the reliability for the solder joint of lead-free solder ball. In order to standardize the test method, the four point impact bending test was applied under the conditions of various frequencies and amounts of +/-amplitude respectively. Effects on the results were analysed. The optimum condition for impact bending test achieved in this study was the frequency of 10 Hz, and the amplitude of (+12/-1)~(+15/-1). 3 kinds of surface finishes Cu-OSP (Organic Solderability Preservative), ENIG (Electroless Nickel Immersion Gold), and ENEPIG (Electroless Nickel, Electroless Palladium, Immersion Gold) were used. Fracture surface showed that cracks were initiated and fractured along the intermetallic layer in the case of surface finishes of Cu-OSP and ENIG, while in the case of ENEPIG the cracks were initiated and propagated in the solder region.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.6
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• pp.1045-1053
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• 2014

In this paper, we assume that the information leakage through side-channel signal may occur from the card payment terminal and newly introduce a real application attack model. The attack model is a side channel attack based on vibration signals, which are detected by a small sensor attached on card terminal by attacker. This study is similar to some other studies regarding side channel attack. However, this paper is different in that it is based on the non-language model. Because the financial transaction information such as a card number, password, mobile phone number and etc cannot have a constant pattern. In addition, there was no study about card terminal. Therefore, this new study is meaningful. We collected vibration signals on card terminal with a small wireless sensor and analyzed signal data with statistical signal processing techniques using spectrum of frequency domain and principal component analysis and pattern recognition algorithms. Finally, we evaluated the performances by using real data from the sensor.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.126-131
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• 2003

Kochang (Chollabuk-Do) located in the west-southern area of the Korea and passed by the West Coast Highway has yellow collar soil(Hwang-To) pertaining primarily clay. Hwang-To serve as a great soil for growing watermelon and yam but are not strong enough to be used as subgrade material for constructing roads. Subgrade material of the study site was not qualified for standard of material quality. Properties of subgrade layers showed that strength of subgrade material is not strong enough to sustain the subgrade strength in constructing roads since No. 200 passing ration is 25 - 82 ％ and ground water level is nearly equal to subgrade level. The objective of this study is to present the methods obtaining proper subgrade strength of cutting area to construct secure and solid highways in the fragile area.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.10a
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• pp.210-211
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• 2009

The container has the inherent number which for distinguish among containers. When containers were handled, the container No. identify work must be precede. The work goes by fond in Most of the ports. It has not only inefficient time and cost but also error as worker's condition. The measure is operated that to use the camera on the spreader of quay crone to solve that problem. This measure, however, showed up the difference q recognition rates at weather, camera's condition, etc The ways could be considered both improvement of hardware and conversion of error number to solve the measure. This paper defines the problem and study an efficient solution.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.294-300
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• 2017

This paper proposes a method for 3-D sound source localization (SSL) using region selection and TDOA. 3-D SSL involves the estimation of an azimuth angle and an elevation angle. With the aim of reducing the computation time, we compare signal energies to select one out of three regions. In the selected region, we compute only one TDOA value for the azimuth angle estimation. Also, to estimate the vertical angle, we choose the higher energy signal from the selected region and pair it up with the elevated microphone's signal for TDOA computation and elevation angle estimation. Our experimental results show that the proposed method achieves average error values of $0.778^{\circ}$ in azimuth and $1.296^{\circ}$ in elevation, which is similar to other methods. The method uses one energy comparison and two TDOA computations therefore, the total processing time is reduced.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.614-621
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• 2004

At present, the electronic document is being processed in WYSWYG mode. For this, a document is structured by the logical structure and the physical structure, and is presented by the markup language. After XML is announced, an application scope of the electronic document is extended from interchanging to searching. However, in point of output quality, a XML document image on a browser has lower quality than a general document image on desktop publishing. The reason is which output function of a browser has not capability for high quality printing. The W3C developed XSL-FO(XSL-formatting Object) for style sheet formatting and PDL(Page Description Language) as like Postscript is already developed and used widely. In this paper, we designed the Postscript-Converter to get a high quality document image by converting XSL-FO into Postscript format.

• Journal of Navigation and Port Research
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• v.27 no.4
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• pp.485-489
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• 2003

The region of Kochang(Chollabuk-Do) located in the west-southern area of the Korea and passed by the West Coast Expressway has the yellow collar soil(Hwang-To) primarily containing clay. Hwang-To serves as a soil appropriate for growing the watermelon and yam, but as a subgrade material not strong for constructing the roads. Particularly, the subgrade material of this study site was not qualified for the standard of the subgrade material quality. The properties of the subgrade layer showed that the strength of the subgrade material was not strong enough to sustain the subgrade strength in constructing the roads since the passing ratio of the No. 200 sieve was about 25％ to 82％ and the ground water level was early equal to subgrade one. Thus, the objective of this study was to present the methods obtaining the proper subgrade strength of cutting area to construct the secure and solid expressways in the fragile area.

• Journal of Navigation and Port Research
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• v.37 no.6
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• pp.681-687
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• 2013

Free Trade Agreement(FTA) aims at abolishing tariffs on trade among nations or regions resulting in having a significant impact on maritime transportation and port. Korea made the first FTA with Chile in 2004 and the trade volume between two countries has seen significant increase. The literature on such impact, however, seems to be very limited. The main purpose of this study is, therefore, to analyze the impact of Korea-Chile Free Trade Agreement on the imported container throughput from Chile at the Busan Port. For this both cross-sectional and time series data are collected that comprise container throughput, Gross Domestic Product (GDP), import tariff, and maritime freight rate, from 2000 to 2011, and the gravity model is applied. The main result of the study shows that the dependent variables, GDP and import tariff are statistically significant, but the maritime freight rate is not consistent with regarding to statistical significance and parameter sign.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1514-1519
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• 2009

We fabricated the GaNLED emitting 400 nm wavelength and improved the optical extraction efficiency by making surface patterns on n-GaN layer and ITO layer above p-GaN. In addition, the light reflection metal under the n and p pad is made and the light reflection metal is installed on the backside of the chip. The light extraction efficiency is increased by 20 % with texturing n-GaN layer and 18% with texturing ITO layer at 20 mA. Compared to planar-surface LED, the light extraction efficiency for surface texturing both n-GaN and ITO is increased by 32% at 20mA.