• Journal of Science and Technology Studies
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• v.18 no.3
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• pp.217-255
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• 2018

Bitcoin, which appeared in 2008, was merely a conceptual virtual currency, but it now enjoys the status as actual money. Bitcoin is an electronic money system that can be traded directly without a central trust institution. Thanks to the popularization of Bitcoin, blockchain technology has become a widespread concern. That technology is expanding not only the currency mechanism, but also a variety of other services. The possibility of a blockchain in relation to actual currency is ongoing. This paper investigates the technological characteristics and social construction of the blockchain by comparing the cases of Bitcoin, Namecoin, and MediBloc among blockchain applications. Namecoin emerged in 2013 is an attempt to replace the centralized Internet Domain Name System(DNS). There has been controversy over that current system for a long time, but replacing the already established system is not easy. Nevertheless, Namecoin has potential as an alternative. Meanwhile, MediBloc is an application that involves distributed management of medical data in South Korea. MediBloc claims that the key producers of medical data are patients themselves. This is to challenge to the question who is a knowledge producer of medical data. Through these three cases, it has discussed that blockchain technology does supports to form more democratic decision-making or simply provide a technical solution as automation. As a citizen, we can intervene in the realization of blockchains by presenting social agenda. This will be a method of the social construction of technology.

• Journal of the Korea Society of Computer and Information
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• v.25 no.3
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• pp.81-88
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• 2020

The Renewable Portfolio Standard(RPS) which is in operated by country for many years is eco-friendly energy business. Although a variety of institute are accessing the RPS, it consists of a centralized system. Also, it shows opacity of data access in user's point of view. And each institutes is possessing their own data collected by themselves. Therefore decentralization and integrated control is demanded. Also, when institutes are attacked, the interruption of RPS can be existed. For resolving this issue, this study proposes the RPS using blockchain. Using the consortium method of blockchain, every institutes has possessing same data inserting REC data in block data, it is resolvable that transparency and security issue as transaction through verification of certain block. Furthermore, in case of one institute is paused by external attack, the role can be replaced by other institutes. This study tried the processing of putting data through ethereum network, therefore it presents the possibility of introducing the blockchain method in RPS.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.5
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• pp.993-999
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• 2015

OTP(One time password) is widely used as an authentication method for financial and other security-sensitive transactions. OTP provides strong security since each password is used only one time while normal password-based authentications use passwords as long term secrets. However, OTP-based authentications relatively lack usability since they require users to hold an OTP card or generator. To overcome such a problem, smartphones start replacing OTP cards and such a method is called smart OTP. However, smart OTP inherits security vulnerabilities that smartphones have. In this paper, we propose a smart OTP authentication based on an extremely light authentication protocol called HB+. HB+ protocol is developed for low-cost devices and has small communication and computation costs. We present our solution and discuss its security, efficiency and practicality. Our contribution is providing a method to securely use smart OTP without losing its efficiency and usability.

• Journal of Korea Game Society
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• v.10 no.2
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• pp.67-80
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• 2010

Investigating the trend of online gamers plays an important role in forecasting, marketing and making policy decision in gaming industry. In this regards, various studies on gamers' trend and characteristics have been conducted. However, these precedent studies show limitation that they're static analysis since they are usually based on the surveys at a certain point. Therefore, this paper aims to identify some implications on forthcoming directions of gaming industry by analyzing dynamic trend of gamers based on the 8 years(from 2002 to 2009) of data from White Paper on Korean Games. Major implications found in this paper are as follows. Negative perception of games increases as the number of gamers increases. Among juveniles, games became a substitute for TV and the amount of time they play games depends on the existence and type of popular games of that time. Also, most item trading is intensively done by a small number of gamers.

• Journal of the KSME
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• v.17 no.4
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• pp.235-256
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• 1977

과거일제하에서는 그 식민정책으로 기계공업을 억제하고 경공업에 치중하였다가 1940년대 전쟁 물자 조달과 대륙침략야옥의 필요상 부분적으로 국내 생산을 하게 되었고 따라서 이에 관련된 토목기계, 광석기계, 농기구, 수송기계, 등의 기계공업이 일어나기 시작한 것이다. 그러다가 조국 이 해방된 기쁨은 안았으나 산업의 위축은 더할 나위 없이 되었고, 6,25동난을 당하여 그나마 대 부분 파괴되었던 과거를 가지고 있는 것이다. 그러다가 1960년대 이후 우리나라 경제개발 1,2,3, 차5개년 계획을 수행하여 현재에 이른 것이다. 먼저 기계공업의 특징을 보면 기계공업은 모든 산업의 생산수단인 기계설비 생산하는 산업이며, 그 파급효과는 전 산업에 미친다. 산업구조의 고도화와 산업의 근대화는 기계공업의 발전없이 이루어질 수 없다. 기계공업은 중화학공업에 있 어서 중구적인 산업이니만큼 기계공업의 발전없는 경제성장에는 한계가 있는것이다. 선진공업 국가들은 수출상품중 기계류수출비중이 일반적으로 50%를 전후하고 있다. 기계류는 다른 상품과 달리 단위 거래규모가 크기 때문이다. 다음에 기계공업은 기술집약, 노동집약 현 산업이다. 우리 나라는 비교적 풍부한 노동력을 가지고 있을뿐아니라 이들 인력은 교육수준이 대체로 높다. 그러기 때문에 기술노동집약적인 기계공업은 고용증대를 갖어오는 반면에 높은 교육수준의 풍부 한 노동력을 통한 발전이 기대되고 있다. 특히 기계고업은 국방력강화라는 점에서 큰 역할을 담당하게 된다. 그러므로 기계공업은 국방력 강화의 기초산업이다. 우리나라 현재의 여건으로서 기게공업은 방의산업으로서의 역할이 크게 요청되고 있다. 우리나라의 경제는 수출의 증대를 통 해서 고도의 경제성장을 유지해야 하겠고 80년대의 자립경제 기반을 구축키 위한 공업화 정책을 추진하고 있어서 중화학공업의 핵심산업으로서 기계공학 및 기술의 획기적인 육성과 발전은 우리나라 경제의 당면 과제인 것이다. 보고에서 필자는 여러 문헌들을 통하여 우리나라 기계공업 의 발 자취를 살피고 현향을 소개하며 아울러 대망의 80년대의 우리나라 기계공업을 전망해 보고 저 한다.

• The Journal of the Korea Contents Association
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• v.17 no.6
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• pp.32-38
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• 2017

Despite the opinion that certificate is useless, half of the population in Korea (approx. 35 million) get an certificate, and use it for internet banking, internet shopping, stock trading, and so on. Most users store their certificates on a usb memory or smartphone, and certificates or passwords stored on such storage media can be easily attacked and used to disguise as legitimate users. Due to these security problem of certificate, a various authentication technologies has been proposed such as smartphone owner authentication using SMS, and a personal authentication using biometric authentication. However, a safe technique is not presented yet without user password, and certificate. In this paper, I proposed a method to secure certificate/private key without a user password using a combination of USIM card and smartphone's information. Even if a hacker gets the user password, the certificate, and the private key, he can not use the certificate. User do not need to remember complex password which is a combination of alphabetic / numeric / special characters, and use his certificate safely.

• Journal of Distribution Research
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• v.12 no.4
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• pp.27-47
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• 2007

Using survey data and the Heckit model that adequately controls the sample selection bias, we analyze shoppers expenditure through two major emerging shopping channels: Internet shopping and TV home shopping channels. Age, Internet experience, daily Internet usage, the number of computers are factors that affect the ratio of consumers' expenditure through Internet shopping relative to the expenditure through TV home shopping. Shopping frequency which represents the shoppers' incentives to reduce transaction costs also has a positive effect on the proportion of shoppers' expenditure through the Internet shopping. Shoppers' perceptions of convenience, reliability, speed, and diversity are also shown to affect shoppers' relative expenditure ratio through Internet shopping. In contrast, shoppers' perception of prices does not seem to affect their purchasing behavior.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.6071-6080
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• 2012

Regarding the official authentication method which is a strong encrypt method for financial transactions, there has recently been a concern for the problem of storage. As a solution for such problems, this study provides the anonymous authentication method based on the smart card used for such a purpose by utilizing the pseudo ID replacing the user's personal data. Such an anonymous authentication method makes it possible to prevent any inside leakage, intermediary attack, limited re-transmission attack, service-denying attack, directional safety attack and secret inspector attack in regard to the user's personal data. As a result, there would be no concern for the leakage of any personal data. In comparative analysis, after executing the comparison and analysis process through the experiment for the authentication process by using the previously-used smart card, the new one has shown about 10% a high level of efficiency for the encrypt and decrypt process together with excellent features in terms of flexibility in regard to the user's anonymity and tracking ability.

• Journal of the Korean Regional Science Association
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• v.33 no.2
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• pp.39-46
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• 2017

This study estimated indirect economic benefits of the introduction of Korean Spatial Information System. Korean academic society has been reluctant to consider indirect benefits as an item of benefits in cost-benefit analysis. Nevertheless, other countries including England recommend to consider some indirect benefits like option value as an important item of cost-benefit analysis, especially in the case of transportation projects. This study estimated indirect benefits of the introduction of Korean Spatial Information System using Contingent Valuation Methods: Indirect benefits of the project are so significant in terms of statistics and substantial in terms of magnitude that decision making can differ from the case without consideration of such indirect benefits.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.292-292
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• 2012

현재 투명전극은 주로 ITO를 사용하고 있으며, ITO는 인듐산화물(In2O3)과 주석산화물(SnO2)이 9대 1의 비율로 혼합된 화합물로 인듐이 주성분이다. 따라서 ITO 사용량의 증가는 인듐의 수요 증가를 이끌어 2003년 이후 인듐 잉곳의 가격이 급등하였다. LCD에 응용되는 금속재료의 가격추이를 비교해보면, 인듐이 가장 큰 변화를 보이고 있으며, 2005년 인듐 가격은 2002년 대비 1,000% 이상 상승하였다가 2007년 이후 500%p 하락하여 2008년 2월 22일 기준으로 톤당 49만 달러에 거래되고 있다. 같은 기간 동안 알루미늄의 가격은 76.6% 상승하였으며 구리는 394%, 주석은 331% 상승하였다. 이러한 인듐의 가격 상승폭은 동일한 기간 동안 다른 금속 재료와 비해 매우 크며, 단위 질량당 가격도 20배 이상 높은 수준이다. ITO의 주성분인 인듐의 이러한 가격의 급등 및 향후 인듐의 Shortage 예상으로 인해 ITO 대체재 확보의 필요성이 증가되고 있다. 태양광 발전산업에서 현재 주류인 결정질 실리콘 태양전지의 변환효율은 꾸준히 향상되고 있으나, 태양전지의 가격이 매년 서서히 하강되고 있는 실정에서 결정질 실리콘 가격의 상승 등으로 고부가 가치 산업유지에 어려움이 있으며, 생산 원가를 낮출 수 있는 태양전지 제조기술로는 2세대 태양전지로 불리는 박막형이 현재의 대안으로 자리매김하고 있으며, 박막태양전지 산업분야가 현재의 정부정책 지원 없이 자생력을 갖추고 또한 시장 경쟁력을 확보하기 위해서는 박막태양전지 개발과 더불어 저가의 재료개발도 시급한 상황이다. 본 연구에서는 In-line magnetron sputtering system을 사용하여 소다라임 유리기판 위에 박막태양전지용 투명전도성 ZnO(Al) 박막을 제작하였고, 특히 이 박막은 n-형 반도체 특성을 가져야하기 때문에 홀이동도와 개리어농도의 상관관계 및 박막의 두께, 광투과율 특성, 온도 의존성을 조사하였고, 이를 논하고자 한다. (본 연구는 중소기업청의 기술혁신개발사업 연구지원금으로 이루어졌음).