• ETRI Journal
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• v.32 no.1
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• pp.112-119
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• 2010

We present a useful design for a free access mat which supports two frequency bands of 2.4 GHz and 5 GHz. The free access mat is a sheet-shaped waveguide which consists of a tightly coupled double-layered microstrip resonator array. It provides easy access for devices in short-range wireless communications. Interference is a common problem with conventional applications which use free space transmission. Our proposed wireless access system uses a subsidiary waveguide, the free access mat. Wireless devices are proximately coupled to the free access mat through which the coupled electromagnetic (EM) wave transmits. The arrival domain of the EM wave of an application is therefore limited to an area close to the free access mat. Wireless devices can be coupled to the free access mat at an arbitrary position without contact. We previously presented a free access mat for a single frequency band. This paper presents a free access mat for the two frequency bands of 2.4 GHz and 5 GHz. The free access mat uses a ring patch resonator array which is easily excited by typical antennas and is resistant to interference. These characteristics are demonstrated by numerical simulation and confirmed by experiment.

• Journal of Satellite, Information and Communications
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• v.5 no.2
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• pp.14-18
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• 2010

The future of communication systems is expected to combine with the terrestrial and satellite networks. A commonality between wireless interfaces is important consideration for cost of user equipment in the integrated satellite and the terrestrial system. Because IMT-Advanced system take into account LTE based on the terrestrial system for the next generation of communication, a study of the LTE-based satellite system is especially required. A frame of the existing terrestrial wireless networks is designed to use for a random access up to the maximum cell radius of 100 km. However, the random access scheme for the terrestrial system cannot be used in the satellite system, because the satellite systems generally have large coverage than the terrestrial system. Therefore, we propose that the efficient random access procedure to reduce latency and complexity for the satellite system maintaining commonality with the terrestrial system in this paper.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10b
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• pp.847-850
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• 2001

본 논문에서는 최근에 많은 관심이 증가하고 있는 보안 운영체제를 위한 접근제어에 대해 기술하고 이 접근제어를 FreeBSD 에 구현한 것에 대해 설명한다. 강제적 접근제어(MAC), 신분 기반 접근제어(DAC), 그리고 역할기반 접근제어(RBAC) 과 같은 접근제어 정책들을 안전한 FreeBSD 운영체제를 위해 접근제어 정책으로 사용하였다. MAC 과 ACL 의 구현은 POSIX1003.le 의 표준에 기준 하였고 RBAC 의 구현은 NIST의 표준을 기준으로 하였다. 강제적 접근제어는 군기관이나 정부 기관의 보안 요구사항들을 만족시켜주지만 보안관리 측면에서는 유동적이지 못한 면이 있다. 반면에 역할기반 접근제어는 상업적 접근제어 정책 요구 사항들을 만족시켜주는 정책으로 유동적이고 다양한 보안 관리 정책의 요구사항들을 만족 시켜준다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.952-957
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• 2008

In this paper, explain about collect that Access Point signal and Implementation of Location Tracking System of Wireless Access Point based PDA. Collect Access point signal in PDA then Signal transmits by computer so Computer is analyze collected signal and is seen on picture. we show the Present problem of wireless LAN and position feeler algorithm through this writing paper.

• Journal of the Korea Society of Computer and Information
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• v.22 no.8
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• pp.55-61
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• 2017

Cloud computing is cost-effective in terms of system configuration and maintenance and does not require special IT skills for management. Also, cloud computing provides an access control setting where SSO is adopted to secure user convenience and availability. As the SSO user authentication structure of cloud computing is exposed to quite a few external security threats in wire/wireless network integrated service environment, researchers explore technologies drawing on distributed SSO agents. Yet, although the cloud computing access control using the distributed SSO agents enhances security, it impacts on the availability of services. That is, if any single agent responsible for providing the authentication information fails to offer normal services, the cloud computing services become unavailable. To rectify the environment compromising the availability of cloud computing services, and to protect resources, the current paper proposes a security policy that controls the authority to access the resources for cloud computing services by applying the authentication policy of user authentication agents. The proposed system with its policy of the authority to access the resources ensures seamless and secure cloud computing services for users.

• Journal of Korea Multimedia Society
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• v.17 no.4
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• pp.433-440
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• 2014

Wireless communication offers the flexibility to the node movement at the spatial dimension more than the wire communication not only in IP architecture but also in Content-Centric Networking. Although it gives such advantage, the intra-domain movement of a node especially the data source node affects the communication to the access point node which in the end affects the acceptance ratio of the client node that requests the data packets from the data source node. In this paper, we use time-division access method to maintain the acceptance ratio of the client node as the effect of the intra-domain data source node movement in Content-Centric Networking. The simulation result shows that the acceptance ratio of the client node can be maintained using the time-division access method as long as the interval access time is less than the coherence time.

• Journal of the Korea Society of Computer and Information
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• v.10 no.1 s.33
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• pp.141-148
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• 2005

Nowadays, it is possible to access sharing data from unauthorized People. Access control prevents unauthorized access to computing resource, information resources, and communication resources. It is very important to defend the critical system resources from the unauthorized. The importance of this study is to develop Protection Profile for Mandatory Access Control (MAC) that satisfies TCSEC assurance level B2. protection profile for MAC will help developers to use reference for the development of requirements and formulating security specification.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.657-663
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• 2010

Today, rapid evolution of Internet makes various types of services in ubiquitous environment are intelligent and active. As a result, user's demand on high quality of life increases and health care service based on ubiquitous environment draws a lot of attention. However, user's private information used for health care service is illegally distributed and exposed, causing serious individual and social problems. Therefore, this thesis is intended to suggest a secure health care service to prevent unauthorized third party's access and to protect user's privacy in health care systems. The proposed scheme establishes a session key through communication channel between health care system and user based on explicit mutual authentication and provides secure communication and access control, improving security as one of the leading health care systems.

• Journal of Korean Library and Information Science Society
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• v.20
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• pp.155-186
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• 1993

This study aims at defining the concept of OPAC, tracing of research trends and development of it, and clarifying various methods of subject access and patterns of bibliographic searching in OPAC as well as strategies for improving to implement online catalogs. Although OPAC is so far the most user-friendly bibliographic searching method, there are still a lot of issues including online subject access in particular. Therefore a more effective and useful method for computer end-users have to be developed, for instance, improvement of an indexing system, a n.0, pplication of the classification system as a searching tool, a new design and construction of standardized thesaurus, betterment of user interface, introducing of expert system into bibliographic searching, establishment of subject authority file. Those would raise the success-rate of users seeking bibliographic information in the library catalogs. Korean libraries are in very early stage of OPAC implementation so that every efforts and concerns to improve strategies and techniques for subject access to OPAC have been strongly asked.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.474-479
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• 2003

We discussed the usage of a radio resource, the spectrum allocation and the trends of policy about 5㎓ band in other countries, We studied about the technical regulation on high speed wireless access system and the spectrum allocation of ISM bard in 5㎓ bard for other countries. We also analyzed the efficient use of radio resource, the method of frequency sharing and the calculation of spec01m requirement in noel to progress the high speed wireless access system In addition We proposed the schemes of domestic spectrum allocation for high speed wireless access system at 5㎓ band