• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.3
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• pp.3-8
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• 2008

In this paper, an planar antenna which has omnidirectional radiation pattern in H-plane and low profile is proposed. By adding inductance elements of an ENG shell structure, a capacitance element of an electrically small antenna is easily achieved with impedance matching. An ENG shell structure is consist of a inductive loading structure which has symmetrical four stepped L-shape slots. The simulated result shows, the impedance bandwidth of the proposed antenna is 150MHz (2.5 ~ 2.65GHz). The simulated maximum radiation gain of proposed antenna is 1.12 dBi at center frequency 2.56GHz. Omnidirectional radiation pattern is achieved. The proposed antenna will be applied to wireless lan access point system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.1996-2001
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• 2006

Open System Authentication Method, Shared Key Method, Mac Based Authentication Method are very hard to use in wireless network that needs security. So now, many researches have been performed about 802.1x and user authentication method applying PKI. but certificate verification protocol has been used abolished list called CRL since it's first usage of PKI, there were still has a problem about distribution point. This paper applied CVS to use CA direct not to use CRL and OSCP server in order to improve this problems. Also It suggested the system that can make authentication steps more shorter using authentication server and Mutual authentication system by public certificate(small size/low speed wireless terminal can access to wireless network fast and safely)

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.73-81
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• 1999

Inchon Port is the second largest import-export port of Korea, and has the point ant issue such as the excessive logistics cost because of the limits of handing capacity and the chronic demurrage. There is few research activities on the analysis and improvement of the whole port operation, because Inchon Port not only has the dual dock system and various facilities but also handles a various kind of cargo. The purpose of this paper is to develop the simulation program as a long-term strategic support tool, considering the dual dock system and the TOC(terminal operation company) system executed from March, 1997 in Inchon Port. The basic input parameters such as arrival intervals, cargo tons, service rates are analyzed and the probability density function for this parameters are estimated. The main mechanism of simulation model is the discrete event-driven simulation and the next-event time advancing. The program is executed based on the knowledge base and database, and is constructed using VISUAL BASIC and ACCESS database. From the simulation model, it is possible to estimate the demurrage status through analyzing scenarios such as the variation of cargo ton and cargo handing level, the increase of service rate, and so on, and to establish the long-term port strategic plan.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1146-1151
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• 2007

In this paper, it is investigated to the security services and vulnerability tools of IEEE802.11 wireless LAN, and it is considered the employment state of wireless LAN AP (access point) and analyzed the state of security vulnerability. In according to this study, among wireless LAN APs, which are operated in each company or each factory, in center around industrial of Cheonan city, 50% of AP, which is used, is not operated on WEP, and therefore, it is stated the weakness of security so far. From the result of this study, in case of mid and small company, it can be distinguished the necessity of the security training for the informaton system manager.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.5
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• pp.109-116
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• 2016

Today various IoT platforms exist, but most of them only consider IPv6, without other types of network including private network. They support, therefore, the private network to use virtual private network or through the hardware gateway. To solve this limitation, we propose a IoT platform that provides IoT Services on private networks. Also we verify this platform though constructing a testbed.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.495-498
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• 2014

최근 스마트폰을 이용한 인터넷 사용이 증가하면서 카페나 영화관과 같은 공공장소에 많은 Access Point(AP)들이 설치되어 있다. 하지만 이러한 AP 대부분이 외부 공격에 무방비하게 노출되어 위험성이 대두되고 있다. 대표적인 공격으로 사용자와 AP간 통신에 끼어들어 데이터를 도청하거나 위 변조하는 Man-In-The-Middle(MITM) 공격이 있다. MITM 공격에 대한 대응책으로 통신간 암호화가 있지만, 모든 통신에 암호화를 적용하는 것은 많은 비용이 발생하기 때문에 현실적으로 불가능하다. 실제로 구글 플레이스토어에 등록된 100개의 무료 인기 어플리케이션 중 모든 메시지에 암호화 통신을 사용하는 어플리케이션은 없으며, 부분적으로 사용하는 어플리케이션은 43개임을 확인하였다. 본 논문에서는 앞서 설명한것과 같이 통신간 암호화를 하지 않는 어플리케이션을 MITM 공격으로부터 보호하기 위한 메시지 인증 기반 무결성 검증 방법을 제안하여 안전한 어플리케이션-서버 통신 모델 개발에 기틀을 마련한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04b
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• pp.1285-1288
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• 2002

Bluetooth wireless technology is a publicly available specification proposed for Radio Frequency (RF) communication for short-range and point-to- multipoint voice and data transfer. It operates in the 2.4GHz ISM(Industrial, Scientific and Medical) band and offers the potential for low-cost, broadband wireless access for various mobile and portable devices at range of about 10 meters. In this paper, we describe the structure and the test results of the bluetooth baseband module we have developed. This module was developed based on IP reuse. So Interface of each module such as link controller UART, and audio CODEC is designed based on ARM7 comfortable processor. We also considered various interfaces of related external chips. The fully synthesizable baseband module was fabricated in a $0.25{\mu}m$ CMOS technology occupying $2.79{\times}2.8mm^2$ area including the ARM TDMI processor. And a FPGA implementation of this module is tested for file and bit-stream transfers between PCs.

• Journal of Korean Society of Rural Planning
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• v.2 no.2
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• pp.67-80
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• 1996

Less Favored Area(LFA) is a newly shaped regional concept and just appearing as a new community design target, where the topogeographical, industry-locational condition and the daily living environment have been outstandingly inferior to any other regions. Community Design(CD) principles that cover a spatial order of settlements are introduced in this study when the CD concept is applied to the LFA. The study puts a great stress on the horizontal and vertical order of communal spatial units and living activities oriented to residents'socio-economic activities, on which a CD district and an inner spatial organization of community is based. Therefore the various relationships between residents' activities and particular places, such as that between agricultural production and land, access to living services and community-outer settlements, is analysed through the field study. The emphatic point is that the spatial unit and organization of community, namely settlement order is casted not only by the horizontal coverage but also by the vertical hierarchy forming a cubic-like spatial order. Applying the CD idea to LFA has limit because the CD has been oriented on urban architectural style and community participation process. Nevertheless, that has a new possibility to understand the fundamental and archetypical change of a spatial pattern of community uncovering the accumulated layer of settlement order especially in the drastically changed mountain community from past to now.

• Current Research on Agriculture and Life Sciences
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• v.26
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• pp.45-54
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• 2008

The purpose of this research is to develope street trees management program for more an effective street trees management. The principal point of this program is to relate spatial data and attribute data that is the main concept in GIS(Geographic Information System). To do this function, MapObjects which is ESRI's mapping and GIS components was used to process spatial data and Access which had been developed by MS was used to manipulate attribute data in this program. Visual Basic also was used to design and develop user interfaces and procedures, relate two sort of data, and lastly complete Application. Relational data model was adopted to design tables and their relation, Antenucci's GIS development model was selected to design and complete this program. The configuration of this application is composed of management data and reference data. The management data includes the location of street tree, a growth condition, a surrounding environment, the characters of tree, an equipments, a management records and etc. The reference data include general information about tree, blight and insects.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.515-517
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• 2003

In this paper we examine the effects of the required portions of guard timing spaces in a MAC frame of ETSI BRAN HIPERLAN/2 system such as inter-mobile guard timing space in UL(Up Link) duration, inter-RCH(Random CHannel) guard timing space, sector switch guard timing space. In particular, we calculate the number of OFDM(Orthogonal Frequency Division Multiplexing) symbols required for these guard timing spaces in a MAC frame. We them evaluate the throughput of HIPERLAN/2 system as we vary parameter such as the guard time values defined in [2], the number of DLCCs(Data Link Control Connections), and the number of RCHs. Finally we show by numerical results that the portions for the 새심 summation of required guard timing spaces in a MAC frame are not negligible, and that they should be properly considered when trying to evaluate the performance of MAC protocol of HIPERLAN/2 system and also when determining the number of RCHs as well as the number of DLCCs in UL PDU trains at an AP/CC(Access Point/Central Controller).