• Proceedings of the Korea Contents Association Conference
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• 2014.11a
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• pp.361-362
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• 2014

본 연구는 기상청에서 제공하는 기상정보를 활용하여 제주도의 대표적인 관광자원 중 하나인 올레길 방문자들에게 더 나은 서비스 제공을 위한 콘텐츠를 개발하는데 목적이 있다. 콘텐츠 개발에 앞서 현재 제주도에 서비스되는 기상정보의 종류를 살펴보고, 올레길 방문자들의 기상정보 활용실태를 설문조사 하였다. 마지막으로 설문결과를 참고하여 올레길 방문자들이 쉽게 활용할 수 있는 스마트폰 앱 콘텐츠를 개발하였다.

• Journal of the Korean Graphic Arts Communication Society
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• v.19 no.1
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• pp.28-41
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• 2001

Rheological properties of ink and Ink-Water balance are the important factors in lithographic printing. Laboratory test method which determines the emulsification rate of dampening solution and ink has been described. The emulsification theory and laboratory test method deduced from Surland and it has become a useful tool for the industry. The effects of pH value and surface tension of dampening solution on the emulsification rate has been tested by many researcher. In this paper we focused on the factors which influence in the emulsification such as pH and surface tension of dampening solution and emulsifying temperature. To study on the factors determining the emulsion velocity, we have measured water pickup and calculated emulsion velocity constant 'k' and activation energy.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.7
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• pp.116-126
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• 1996

In this paper, we propose a new termination rule for the iterative restoration of degraded images, by which the number of iterations can be dramatically reduced. This rule uses a parameter, called noise suppression factor (NSF), to appropriately teminate the iteration process, reduces a lot the computational load, and avoids the amplification of noise for the better quality. We also propose a method using the morphological filters, when applied to the resulting image, that will significantly reduce the ringing effect which would otherwise exist in the boundary of the image. Simulation with the blurred lena image with gaussian noise showns that the proposed termination rule combined with the morphological filtering gives the restored image with much improved quality.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.11
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• pp.1383-1392
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• 1995

In this paper, the method to incorporate TCVQ(Trellis Copded Vector Quantizer) into the encoding of the wavelet trans formed(WT) image followed by a variable length coding(VLC) or an entropy coding(EC) is considered. By WT, an original image is separated into 10 bands with various resolutions and directional components. TCVQ used to compress these WT coefficients is a finite state machine that encodes the input source on the basis of the current input and the current state. Wavelet basis used in this paper is designed by orthogonal spline function. A modified set partitioning algorithm to Wang's is also presented. A simple modification to Wang's algorithm gives a highly time-efficient result. Proposed WT-TCVQ encoder shows a very competitive result, giving 37.46dB in PSNR at 1.002bpp when encoding 512$\times$512 LENA.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10A
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• pp.1486-1491
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• 2000

A Multicarrier system required a lower speed paralled-type of signal processing in contrast to a fast serial processing in a single carrier CDMA system. For the analysis we evaluate MC-CDMA system performance with that of a single-carrier CDMA system and a multi-carrier CDMA system based on the various jamming conditions. Also we studied to the capacity level against the threat environment through the performance comparison in commercial CDMA system and Limiting repeater system. as a result we found that M-CDMA system has a robustness to narrowband interference and multipath environments like as a Rayleigh fading.

• Proceedings of the Korea Contents Association Conference
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• 2018.05a
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• pp.63-64
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• 2018

강수확률예보에 대한 사용자 행동을 이해하고, 만족도의 변화를 분석하기 위해 2017년 조사된 설문조사 결과를 도입하고, 예보의 가치평가 분야에서 널리 활용되어 온 가치스코어를 만족도 평가에 사용하였다. 분석 결과 예보사용자들은 확률예보를 효율적으로 사용할 수 있는 적절한 임계확률을 인지하지 못한 것으로 나타났다. 동일한 예보라도 분석 시기에 따라 사용자의 불만족 정도가 만족도에 미치는 영향은 다르게 나타날 수 있으므로 사용자들이 민감하게 반응하는 시기를 적절히 구분하여 분석할 수 있어야 할 것이다. 그리고 분석 기간 및 연령에 따라 사용자들의 의사결정 기준인 확률예보의 임계확률을 변화시키는 것만으로 일부 사용자 그룹의 만족가치를 향상시킬 수 있는 것으로 나타났다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.745-748
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• 2009

본 논문은 ZigBee 기술을 이용하여 실내 위치 인식 알고리즘을 설계하고 구현하였다. ZigBee의 가장 큰 장점은 RFID, 적외선, 초음파 기술 등과 비교하여 저전력으로 오랜 시간 동안 사용할 수 있으면서도 가격이 저렴하다는 것이다. 본 논문은 ZigBee를 이용한 위치 인식 기술에 RSSI와 삼각 측량법, 그리고 다수의 데이터에서 정확한 RSSI값을 선택하는 알고리즘을 설계하였고, 위치 인식의 정확도를 높이는데 초점을 두었다. RSSI값을 미리 실측하여 Curve Fitting을 이용하여 각각의 고정 AP마다 RSSI와 거리의 관계식을 산출하여 위치 계산에 사용하였다. 또한 실제 위치 인식 시스템을 기존의 삼각 측량법만을 사용하는 방법과 본 논문에서 제안하는 방법을 각각 구현하였다. 또한 모의실험을 통해 실제 모바일 노드의 위치와 측정된 위치의 오차율을 비교하여 성능을 측정하였다. 모의실험을 통해 성능을 비교하여 모바일 노드의 위치 인식 오차율을 줄이고, 정확도를 향상하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6A
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• pp.864-870
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• 1999

A key difference between a tactical military and commercial satcom system is that the military system is expected to provide a service in the presence of ECM threats such as jamming. In this paper, we analyzed the three different type of link system applicable to the military satellite and directly compared to each system in order to find system performance according to the maximum jammer power. For the analysis, we modeled and simulated the SHF satellite system based on uplink jamming. From the results, it is found for each different type of link the maximum jammer power that can be tolerated with link operating at its suggested nominal rate. Also, we studied to the survivability level against the jamming condition through the performance comparison in shipborne and portable terminal consistent with frequency.

• The KIPS Transactions:PartB
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• v.13B no.3 s.106
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• pp.315-322
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• 2006

Ant Colony System(ACS) is easily applicable to the traveling salesman problem(TSP) and it has demonstrated good performance on TSP. Recently, ACS has been emerged as the useful tool for the pattern recognition, feature extraction, and edge detection. The edge detection is wifely utilized in the area of document analysis, character recognition, and face recognition. However, the conventional operator-based edge detection approaches require additional postprocessing steps for the application. In the present study, in order to overcome this shortcoming, we have proposed the new ACS-based edge detection algorithm. The experimental results indicate that this proposed algorithm has the excellent performance in terms of robustness and flexibility.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6C
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• pp.594-601
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• 2003

High-speed WLAN(Wireless Local Area Network) systems operating in 5GHz band use OFDM transmission technique. OFDM technique transmits data in parallel and has many advantage compared with the serial transmission system-for example, robustness to time variance of channel. OFDM technique use the orthogonal multicarriers. The ICI(InterChannel Interference) caused by the orthogonality destruction between subcarriers. hamper the BER performance. In this paper, we propose the synchronization techniques for high-speed WLAN system designed to support user data rates up to 54Mbps at 5GHz. The proposed synchronization techniques are the reduced complexity structure having the similar performance compared with the conventional synchronization techniques.