• 디지털콘텐츠학회 논문지
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• 제8권4호
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• pp.607-613
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• 2007

Current changes in the written language curriculum have lead to emphasis being placed on the process involved in writing rather than the product. Writing is being viewed as a means of exploration, with text being manipulated in revision until a clear message is conveyed. This study focuses on the use of the computer in written language, as a tool to facilitate learning, increase interaction and alter children's attitudes. Some children from a local primary school participated in a project which gave them access to a computer and guidance during the process of revision. Evaluation of this study showed a two-fold effect. Firstly the writing behaviors of the children developed with their increased involvement in the process. For example, the children began to read what they had written thereby independently evaluating the content. Secondly, arising from this, as a sense of control over their writing was gained the children's attitudes towards writing became more positive.

• Journal of Information Processing Systems
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• 제13권4호
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• pp.653-667
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• 2017

The significant advances in information and communication technologies are changing the process of how information is accessed. The internet is a very important source of information and it influences the development of other media. Furthermore, the growth of digital content is a big problem for academic digital libraries, so that similar tools can be applied in this scope to provide users with access to the information. Given the importance of this, we have reviewed and analyzed several proposals that improve the processes of disseminating information in these university digital libraries and that promote access to information of interest. These proposals manage to adapt a user's access to information according to his or her needs and preferences. As seen in the literature one of the techniques with the best results, is the application of recommender systems. These are tools whose objective is to evaluate and filter the vast amount of digital information that is accessible online in order to help users in their processes of accessing information. In particular, we are focused on the analysis of the fuzzy linguistic recommender systems (i.e., recommender systems that use fuzzy linguistic modeling tools to manage the user's preferences and the uncertainty of the system in a qualitative way). Thus, in this work, we analyzed some proposals based on fuzzy linguistic recommender systems to help researchers, students, and teachers access resources of interest and thus, improve and complement the services provided by academic digital libraries.

• Journal of information and communication convergence engineering
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• 제2권2호
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• pp.128-131
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• 2004

We suggest resource authorization system based on RBAC admitting someone to access resources. In existing grid environment, The authorization mechanism on user's resource is to give users an authority on the basis of DN(Distinguished Name) of proxy certificate and map file mapped in local system ID by one-to-one. In this case, it is difficulty in resource management such as each accounting management, memory resource, and disk resource, if the number of users, who want to use them is increased. To solve this problem, we specify the role of user's task in extension fields of his proxy certificate instead of the authorization mechanism of user's ID and propose resource authorization system being able to access his resource.

• 한국산학기술학회논문지
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• 제8권6호
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• pp.1394-1401
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• 2007

안전한 접근제어는 많은 수의 사용자와 정보자원을 가지고 있는 대규모의 조직, 정보시스템에서 매우 중요한 관심사이다. 많은 경우에 시스템 개발자들은 응용 시스템의 일부로서 접근제어 모듈을 구현해야 한다. 이러한 방식은 접근제어 모듈의 수정을 어렵게 하고, 새로운 응용 시스템을 개발할 때마다 반복적으로 접근제어 모듈을 개발해야 하는 문제가 있다. 본 논문에서는 Java를 사용하는 개발 환경을 위한 접근제어 Java API 라이브러리의 구현에 대해 제시한다. 개발자들은 제안된 라이브러리를 활용하여 쉽게 접근제어 모듈을 구현할 수 있다. 제안된 라이브러리는 주요 접근제어 모델뿐만 아니라 도메인 기반, 객체 중심의 접근제어와 같은 새로운 모델도 지원한다. 또한 여러 접근제어 모델을 동시에 적용할 수 있는 기능을 포함하고 있다.

• 정보관리학회지
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• 제7권1호
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• pp.96-120
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• 1990

학술 연구 전산망은 연구자에게 정보 자원과 부가 가치가 높은 정보 서비스를 제공 하며 결과적으로 연구자의 연구 활동과 연구 생산성에 큰 변수로써 영향을 미치고 있다. 본 고는 연구자들간에 유용한 정보 유통 도구로써 정착해 가고 있는 학술 연구 전산망의 제기 능과 연구 활동에 있어서 그의 역할을 고찰하였으며, 한국의 학술 연구 전산망 현상을 조사 분석하고 그 방향을 전망하였다.

• Journal of Communications and Networks
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• 제5권3호
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• pp.187-196
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• 2003

We consider the use of error control coding in direct sequence-code-division multiple access (OS-COMA) systems that employ multiuser detection (MUO) and space diversity. The relative performance gain between Reed-Solomon (RS) code and convolutional code (CC) is well known in [1] for the single user, additive white Gaussian noise (AWGN) channel. In this case, RS codes outperform CC's at high signal-to-noise ratios. We find that this is not the case for the multiuser interference channel mentioned above. For useful error rates, we find that soft-decision CC's to be uniformly better than RS codes when used with DS-COMA modulation in multiuser space-time channels. In our development, we use the Gaussian approximation on the interference to determine performance error bounds for systems with low number of users. Then, we check their accuracy in error rate estimation via system's simulation. These performance bounds will in turn allow us to consider a large number of users where we can estimate the gain in user-capacity due to channel coding. Lastly, the use of turbo codes is considered where it is shown that they offer a coding gain of 2.5 dB relative to soft-decision CC.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권10호
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• pp.4136-4156
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• 2020

Recently, data can be safely shared or stored using the infrastructure of cloud computing in various fields. However, issues such as data security and privacy affect cloud environments. Thus, a variety of security technologies are required, one of them is security technology using CP-ABE. Research into the CP-ABE scheme is currently ongoing, but the existing CP-ABE schemes can pose security threats and are inefficient. In terms of security, the CP-ABE approach should be secure against user collusion attacks and masquerade attacks. In addition, in a dynamic cloud environment where users are frequently added or removed, they must eliminate user access when they leave, and so users will not be able to access the cloud after removal. A user who has left should not be able to access the cloud with the existing attributes, secret key that had been granted. In addition, the existing CP-ABE scheme increases the size of the ciphertext according to the number of attributes specified by the data owner. This leads to inefficient use of cloud storage space and increases the amount of operations carried out by the user, which becomes excessive when the number of attributes is large. In this paper, CP-ABE access control is proposed to block access of withdrawn users in dynamic cloud environments. This proposed scheme focuses on the revocation of the attributes of the withdrawn users and the output of a ciphertext of a constant-size, and improves the efficiency of the user decryption operation through outsourcing.

• International Journal of Advanced Culture Technology
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• 제4권4호
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• pp.70-74
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• 2016

Electronic commerce (E-commerce) using virtual reality (VR) has the advantage of being able to purchase products without restrictions of time and location by overcoming the limitations of existing offline transactions. It is still a rudimentary but fast growing technology, and the use of E-commerce in VR is expanding. The barriers that consumers might face in utilizing E-commerce in VR is the relevance to Information and Communications Technologies (ICT) technology. Fundamentally, it requires Internet access and use through PCs or mobile devices such as smart phones. Because unlike off-line markets, it is difficult to determine the purchase patterns of customers, customer purchasing behavior analysis must be done using computer access records. In order to expand and develop E-commerce in VR in the future, learning ability should be improved through combining with artificial neural network by deep learning that is recently in the spotlight, and the ability to overcome errors need to be improved to enable use in various fields.

• 방송공학회논문지
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• 제21권1호
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• pp.113-116
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• 2016

무선 인지 네트워크(cognitive radio network)는 주파수 사용을 허가받지 않은 이차 사용자들이 일차 사용자의 통신을 방해하지 않으면서 일차 사용자의 주파수를 사용하도록 하는 기술이다. 본 논문에서는 무선 인지 네트워크에서 다수의 이차 사용자(secondary user)가 하나의 일차 사용자(primary user)의 주파수를 사용할 때 이차 사용자들 간의 충돌을 줄이면서 스펙트럼을 사용할 수 있는 다중 접속(multiple access)을 제안한다. 다중 접속은 p-persistent와 non-persistent 방법을 이차 사용자 네트워크에 적합하게 변형하여 사용하였다. 각 다중 접속 방식에 대해서 전체 이차 사용자의 처리율(throughput)을 수식으로 유도하였고, 이를 몬테카를로(Monte Carlo) 모의실험을 통해 검증하였다. 모의실험 결과 채널 접속 확률 및 최대 대기 프레임 숫자를 적절하게 잡아야 처리율이 최대가 됨을 확인하였다.

• 한국컴퓨터정보학회논문지
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• 제7권2호
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• pp.46-52
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• 2002

모바일의 확산, 이동성, 그리고 휴대성은 유선 인터넷의 추세를 점차 무선 인터넷으로 전이시키고 있다. 이에, 기업의 일선 업무 담당자들과 일반인들은 모두 모바일 폰. PDA를 활용하여 지역에 관계없이 이동을 하면서 기업정보와 국가정보에 접근할 수 있게 되었다. 이에 따라 기업정보 도용과 개인정보를 악용하는 경우가 자주 등장함에 따라 정보보호가 사회전반에 큰 이슈화되고 있다. 본 논문에서는 정보보호를 위한 침입탐지 시스템을 설계하고자, 유선 인터넷의 침입 유형과 침입탐지 기법을 살펴보았다. 본 논문은 모바일 무선 인터넷에 의한 시스템 접근 시에 침입을 탐지, 분리하며, 정상으로 가장하여 시스템 내부에 침입한 경우를 탐지하고자 circuit patrol을 시스템 내부에 위치시켜 정상적인 것처럼 시스템에 들어온 침입에 대한 공격을 탐지하는 모델을 제시하였다.