• Journal of Communications and Networks
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• v.11 no.4
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• pp.384-389
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• 2009

Optical wireless communication (OWC) systems are rapidly gaining popularity as effective means of transferring data at high rates over short distances. OWC facilitates rapidly deployable, lightweight, high-capacity communication without licensing fees and tariffs. Nevertheless, the performance of this new technology depends strongly on the atmospheric conditions and the characteristics of the link. In this work, we study the influence of these parameters on both the average (ergodic) capacity and the outage capacity of an OWC system over moderate to strong turbulence channels modeled by gamma-gamma distribution. Moreover, we compare the results that we obtain estimating the average and outage capacities.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05c
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• pp.2169-2172
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• 2003

네트웍을 이용한 외부의 침입을 탐지하기 위해 침입탐지시스템이 1980년대부터 연구되었다. 침입탐지 시스템은 침입을 발견하면 경보데이터나 로그데이터를 생성하는데 서로 상이한 데이터 집합으로 인해 별도의 데이터 매핑이 필요한 문제점을 해결하고자 IETF 의 침입탐지 관련 그룹인 IDWG 에서 IDMEF를 제안하였다. 본 논문에서는 이러한 IDMEF 형식을 지원하는 경보데이터 구조를 설계하고, 이를 통하여 상위의 보안제어서버에서 상이한 침입탐지 시스템으로부터의 경보데이터를 저장, 관리할 수 있는 방법을 제공한다 이러한 기본적인 경보데이터 관리 이외에 저장된 경보데이터를 통한 공격자 정보 추출, 피해 호스트 정보 추출등의 부가적인 방법 또한 제공한다.

• Journal of the Korea Safety Management & Science
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• v.4 no.4
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• pp.63-71
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• 2002

Accident analyses are used to identify common factors contributing to occupational accidents and to give recommendations for accident prevention. This study concerns with the accident characteristics and prevention in the telecommunication service industry. To investigate the accident characteristics, we used workers' compensation reports and employers' accident analysis reports. Three hundred and forty-five injury accidents which results in more than 4 days absence were surveyed. These data were used to investigate the accident characteristics in terms of company size, injured person's age, work experience, accident time, activity at time of accident, accident type, injured body part, and accident agency. We propose the accident prevention policy based on the accident characteristics. These results can be used to develop more effective occupational safety management policies in the telecommunication service industries.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.257-258
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• 2007

In real-time video communications, the large fluctuation of bits generated from contiguous frames may lead to the buffer oveflow and the delay of transmitting video data. This paper proposes a method that the bits generated from each frame may be in the range of specified fluctuation. The method uses a scene change detector and ignores the time information of detected frames. The experimental results indicate that our scheme achieves average PSNR gain of 2.0dB over TMN8.

• Journal of Korean Institute of Industrial Engineers
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• v.27 no.2
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• pp.176-180
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• 2001

In Korea, the mobile telecommunication service market is expanding rapidly and becoming more competitive. For service providers in such a dynamic environment, it is very important to accurately forecast demand including market potential in order to work out marketing strategies. In this paper, we suggest a general approach to forecast the market potential using a multinomial logit model, which is applied to individual-level market survey data. Then we develop a dynamic market potential model that can adapt to changes in the external environment without requiring further market survey. The proposed model is applied to the mobile telecommunication service market in Korea.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.152-154
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• 2018

사물인터넷 기술이 에너지 분야에 이미지 데이터가 사용되면서 데이터 보안과 프라이버시에 대한 문제가 점차 커지고 있다. 이미지 데이터는 일반적인 텍스트 데이터와는 달리 가로, 세로 그리고 대각선의 인접한 픽셀 정보들이 강한 연관성과 상관성을 가지기 때문에, 기존에 사용되었던 암호화 알고리즘과는 다른 기술이 사용되어야 한다. 본 논문에서는 이미지의 직관성과 인접 픽셀 간의 강한 연관성을 제거하기 위해 루빅스 큐브 방식을 활용하는 암호화 알고리즘을 제안한다. 제안된 알고리즘을 구현하고, 널리 사용되는 암호화 알고리즘들과의 비교실험을 통해 제안된 알고리즘이 선택적 평문 공격에 대해 강성을 갖는다는 것을 보인다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.2
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• pp.657-667
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• 2019

This paper studies synthetic aperture radar (SAR) imaging problem which the scatterers are often distributed in block sparse pattern. To exploiting the sparse geometrical feature, a Kronecker constrained SAR imaging algorithm is proposed by combining the block sparse characteristics with the multiway sparse reconstruction framework with Tucker modeling. We validate the proposed algorithm via real data and it shows that the our algorithm can achieve better accuracy and convergence than the reference methods even in the demanding environment. Meanwhile, the complexity is smaller than that of the existing methods. The simulation experiments confirmed the effectiveness of the algorithm as well.

• International Journal of Advanced Culture Technology
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• v.11 no.1
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• pp.370-375
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• 2023

As we enter a super-aged society, studies are being conducted to reduce complications and deaths caused by falls in elderly adults. Research is being conducted on interventions for preventing falls in the elderly, wearable devices for detecting falls, and methods for improving the performance of fall detection algorithms. Wearable devices for detecting falls of the elderly generally use gyro sensors. In addition, to improve the performance of the fall detection algorithm, an artificial intelligence algorithm is applied to the x, y, z coordinate data collected from the gyro sensor. In this paper, we develop a wearable device that uses a gyro sensor, body temperature, and heart rate sensor for health management as well as fall detection for the elderly. In addition, we develop a fall detection and health management system that works with wearable devices and a guardian's mobile app to improve the performance of the fall detection algorithm and provide health information to guardians.

• Journal of Advanced Navigation Technology
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• v.8 no.1
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• pp.1-9
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• 2004

In this paper, we have studied the reliable scheme for transmission of digital watermarking-inserted image data through wireless channel. Multimedia data and watermarking data are degraded because of the high BER (Bit Error Rate) and the effect of fading in wireless channel. We adapt the error correction scheme for mitigating the degradation in watermarking data. We have evaluated the error performance of watermarking data modulated by OFDM/16QAM and sent through Rician fading channel. The simulation results show that when error correcting scheme is used the watermarking data can be detected without severe error even though watermarking-inserted image data is suffered from severe damage.

• Journal of Digital Convergence
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• v.12 no.9
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• pp.177-192
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• 2014

Telematics is a compound word derived from telecommunication and informatics, which provides wireless data service such as traffic information, living information, remote control, maintenance and etc. in a vehicle using GPS(Global Positioning System) and telecommunication. Telematics acceptance was investigated to analyze characteristics of telematics service and its market by using a theoretical technology acceptance model based on literature review. In this paper, valid factors, influencing telematics service acceptance, have been drawn in terms of user ease-of-use, usefulness and service characteristics. Modified measuring variables were used by referring to previous researches.