• Review of KIISC
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• v.8 no.3
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• pp.83-104
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• 1998

인터넷의 급속한 확산과 전세계 통신서비스의 확장으로 인해 세계는 정보의 공유와 다양한 삶의 변화를 가져오고 있다. 교통수단의 발달로 전세계가 일일생활권에 접어들었다면 인터넷과 통신수단의 발전으로 인해 세계는 동일문화권을 형성하고 있다. 주체할 수 없이 수많은 정보와 서비스속에서 사고 있지만, 아직도 좀더 편리하고 안전한 정보의 공유와 윤택한 삶을 영유하기 위한 많은 문제점이 있으며, 이러한 발전 속에서 더 많은 문제점들이 나타나고 있는 것이 현실이다. 또한 이러한 문제점들을 해결하기 위한 다양한 해결책들이 쏟아져 나오고 있다. 본 고에서는다루게 될 내용은 전체적인 공개키 기반구조를 살펴보고 이를 디지털 위성방송 한정 수신 시스템에 적용한다. 공개키 기반구조에 대해서는 인터넷에서 사용자를 인증하기 위한 X.509 인증서에 대해 살펴보고, 인증서를 이용한 서비스에 대해 살펴본다. 또한 최근 각 나라별 공개키 기반구조 표준안의 진행 상황을 알아보고 IETF PKIX 표준안으로서 공개키 관리 프로토콜, CRL CRL 확장, 인증서, 그리고 인증서 확장에 대해 살펴본다. 곧 실현될 디지털 위성방송의 유료화 서비스는 가입자 인증과 서비스에 대한 접근 통제가 가능해야 한다. 따라서 가입자에 대한 관리부분에 공개키 기반구조를 적용함으로써 가입자에 대한 인증과 서비스 및 접근 통제를 가능하게 한다.

• Proceedings of the Korea Association of Information Systems Conference
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• 2004.11a
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• pp.454-461
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• 2004

성과간에 차이가 발생하고 있다. 따라서 고객의 확보와 사용 확대를 통해 창출된 가치로부터 수익을 얻는 가치 전유(Value Appropriation)에 대한 전략적 관심이 증대되고 있다. 본 연구는 가치 전유 측면에서 인터넷 비즈니스의 성공 방안을 제시한다. 인터넷 비즈니스의 성공을 위해서는 더 많은 가치를 창출하는 것만으로는 부족하며, 동시에 그 가치의 더 많은 부분을 전유하는 것이 필수적이다. 인터넷 비즈니스에서 가치 전유의 특성을 분석하고 한국 포털 사업의 사례를 통하여 가치 전유의 방법을 도출한다. 인터넷 매체는 가치의 전유를 어렵게 하며, 특히 고객으로부터의 가치 전유가 매우 중요하다. 인터넷 비즈니스에서 가치 전유는 크게 '직접적인 유료화', '간접 수익의 확대', 그리고 '가치 창출에 고객의 참여 유도'의 측면에서 이루어지고 있다.

• Journal of the Korea society of information convergence
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• v.7 no.1
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• pp.47-53
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• 2014

This study was carried out recognition and status changes of optician for glasses fitting. It based on a survey results of twice in relation to the glasses fitting. The results are as follows. The ratio of glasses fitting about optician operation appeared to increase gradually. The positive awareness change appeared from the customer and optician about the cost charging about the glasses fitting. In the case of a plastic glasses, the burden for the inconvenience feeling and fitting frequency showed an increase with relation to the temple fitting. To reduce the burden of glasses fitting, The continuous education for the correct glasses usage need.

• Journal of Digital Convergence
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• v.13 no.7
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• pp.333-340
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• 2015

Mileage system in some online media, I have a lot of use. In addition, there are a lot of companies that are making money by using the mileage system. A mileage system is the first airline in such a way that the service in the late 1980s, many states now listed sungineung and features. In addition, there are many industries that reported good results using a mileage system used by carriers in other industries. However, mileage of the current game industry has not been introduced, it is not the service by using the concept of point returning to the user is purely a function of mileage. So a lot of developed payment systems in the mobile industry since 2010, proposed a better and more current online payment systems industry has an easy hybrid revenue model for mobile games service convergence mileage using this system.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.327-337
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• 2018

The Korean-style Collection RPG is a unique sub-genre of RPG developed in a new environment of the smartphone era. Based on CCG in Japan, the Korean collection RPG was able to have its own color by adding action style based on the experience of MMORPG development. Since the genre, many games have been released and have had amazing success. This success is not only limited to domestic but also extends overseas. In this study, I try to find out the reasons for the emergence and success of the Korean collection RPG, and analyze "Seven Knights", which has been a great success in Korea, and "Summoners War", which has achieved great success in the world. Through this, I will contribute to the competitiveness of Korean smartphone game industry.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6C
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• pp.648-658
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• 2003

As the usage of image/video contents increase, a security problem for the payed image data or the ones requiring confidentiality is raised. This paper proposed an image encryption methodology to hide the image information. The target data of it is the result from quantization in wavelet domain. This method encrypts only part of the image data rather than the whole data of the original image, in which three types of data selection methodologies were involved. First, by using the fact that the wavelet transform decomposes the original image into frequency sub-bands, only some of the frequency sub-bands were included in encryption to make the resulting image unrecognizable. In the data to represent each pixel, only MSBs were taken for encryption. Finally, pixels to be encrypted in a specific sub-band were selected randomly by using LFSR(Linear Feedback Shift Register). Part of the key for encryption was used for the seed value of LFSR and in selecting the parallel output bits of the LFSR for random selection so that the strength of encryption algorithm increased. The experiments have been performed with the proposed methods implemented in software for about 500 images, from which the result showed that only about 1/1000 amount of data to the original image can obtain the encryption effect not to recognize the original image. Consequently, we are sure that the proposed are efficient image encryption methods to acquire the high encryption effect with small amount of encryption. Also, in this paper, several encryption scheme according to the selection of the sub-bands and the number of bits from LFSR outputs for pixel selection have been proposed, and it has been shown that there exits a relation of trade-off between the execution time and the effect of the encryption. It means that the proposed methods can be selectively used according to the application areas. Also, because the proposed methods are performed in the application layer, they are expected to be a good solution for the end-to-end security problem, which is appearing as one of the important problems in the networks with both wired and wireless sections.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5C
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• pp.664-672
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• 2004

Widespread popularity of wireless data communication devices, coupled with the availability of higher bandwidths, has led to an increased user demand for content-rich media such as images and videos. Since such content often tends to be private, sensitive, or paid for, there exists a requirement for securing such communication. However, solutions that rely only on traditional compute-intensive security mechanisms are unsuitable for resource-constrained wireless and embedded devices. In this paper, we propose a selective partial image encryption scheme for image data hiding , which enables highly efficient secure communication of image data to and from resource constrained wireless devices. The encryption scheme is invoked during the image compression process, with the encryption being performed between the quantizer and the entropy coder stages. Three data selection schemes are proposed： subband selection, data bit selection and random selection. We show that these schemes make secure communication of images feasible for constrained embed-ded devices. In addition we demonstrate how these schemes can be dynamically configured to trade-off the amount of ded devices. In addition we demonstrate how these schemes can be dynamically configured to trade-off the amount of data hiding achieved with the computation requirements imposed on the wireless devices. Experiments conducted on over 500 test images reveal that, by using our techniques, the fraction of data to be encrypted with our scheme varies between 0.0244％ and 0.39％ of the original image size. The peak signal to noise ratios (PSNR) of the encrypted image were observed to vary between about 9.5㏈ to 7.5㏈. In addition, visual test indicate that our schemes are capable of providing a high degree of data hiding with much lower computational costs.