• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.11
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• pp.1667-1674
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• 2010

The fatigue life is estimated while determining the reliability of aircraft structures. In this study, the estimation of fatigue life was carried out on the basis of a cumulative damage theory; the working S-N curve and the equivalent stress on the engine support structure significantly affect the safety of the aircraft. The maximum stress observed was 1,080 MPa in the case of scissors link under crash load condition, and there was a 5% margin for the allowable stress corresponding to the temperature reduction factor. The maximum stress was 876 MPa, and the stress equation coefficient had a maximum value of 0.019 MPa/N in the case of scissors link under fatigue loads. In the results of the fatigue life analysis, the safety life in a fretting area of scissors link upper part was 416,667 flight hour, and other parts showed to infinite life. Therefore, it was demonstrated that the fatigue life requirement of aircraft engine support structure (scissors link, straight link) could be satisfied.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.2
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• pp.128-136
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• 2001

This paper evaluates the performance of an optic link in a frequency conversion based fiber-radio system. The proposed link structure simplifies a BS(base station) via making the MMW(millimeter wave) optical pilot tone generated in the CS(control station) be used in the uplink as well as in the downlink. To acquire the optical pilot tone, an EOM(electro-optic modulator) in the CS is biased in three different ways, i.e., MAB(maximum bias), MIB(minimum bias), QB(quadrature bias). We, depending on the biasing of the EOM, evaluate the link performances in two cases; one is for constant laser source power and the other for constant received DC optical power at a PD(photo detector). Based on the simulation results on the downlink CNR and the uplink SFDR(spurious free dynamic range), we finally deduce the effective EOM biasing for each case.

• Journal of Korean Library and Information Science Society
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• v.43 no.2
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• pp.247-271
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• 2012

The institutional repository and linked data share a purpose, co-creation and joint usage of information resources. Therefore, a new approach linking these two concepts can be utilized for co-production and utilization of resources. This study hoped to configure the Korean dCollection repository as linked data. For this purpose, first, we analyzed the current data structure of dColleciton. Second, we investigated the resource types which dCollection is targeting. Third, we focused and analyzed a case study of resource types targeted by dCollection constructed as linked data. Fourth, this study examined in detail how to build the linked dCollection data and how to connect this linked data to the linked cloud. Finally, we discussed the problems that might oc cur in the process of building the linked data.

• Journal of Satellite, Information and Communications
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• v.12 no.2
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• pp.21-27
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• 2017

The combat systems in Korea navy have been operating some kinds of tactical data link systems such as Link-11, ISDL and JTDLS. Each tactical data link system has the ability to transmit and receive tactical information like track, engagement, weapon information by using unique message of theirs. And each unique message has their own format. But a number of tactical data link system make combat effectiveness worse because their major functions are duplicated unnecessarily. So, many advanced countries are trying to make united data link system. Similarly, the combat systems in Korea navy will operate C4I data link system, and it is combined version current ISDL, KNCCS and JTDLS data link system. In this paper, we consider the development current tactical data link systems in Korea navy. Also, compare the characteristics between I-message used in ISDL and Host-Interface message used in C4I. From these results, we analyze advanced points about C4I data link system.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.7
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• pp.865-874
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• 2016

This research is concerned with the experimental investigation on the vibrations of a flexible two-link system for verifying the theoretical result from simplified equations of motion for the system along with the kinematical synthesis are proposed to simulate the elastic vibrations of a previous study. The structure consists of flexible two-links; The link 2 is attached to the end of the link 1. The link 1 is made of composite fiber reinforced polymer and the link 2 is an aluminum beam. In order to verify the theoretical result, a flexible two-link system operated by the AC and RC servo motors was constructed. Experimental results show that the dynamic modeling approach and the kinematical synthesis proposed in this paper are effective.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10a
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• pp.184-186
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• 2000

이 연구에서는 텍스트 문서를 웹에서 HTML 문서 형태로 효율적으로 검색할 수 있는 변환 시스템을 개발하였다. 웹상에 사용자가 원하는 부분만을 HTML 문서 형태로 제공하도록 문서의 논리적인 구조를 파악하며 그 구조에 대한 정보와 각 논리 단위에 해당하는 부분의 범위 정보를 저장할 수 있도록 관계형 데이터베이스 스키마를 개발하였다. 개발한 시스템은 문서의 목차 테이블을 자동으로 구축하고 목차 테이블의 각 항목에 하이퍼링크를 설정한다. 문서를 웹에서 검색하기 위한 첫 화면은 목차 테이블이며, 그 중 한 항목이 클릭되면 그 항목의 내용이 제공되고, 만약 그 하위에 속하는 항목들이 있다면 그들에 대한 링크를 역시 제공한다. 이러한 방법으로 한 문서의 전체를 그 논리 구조에 따라 사용자가 원하는 대로 검색할 수 있다. 이 시스템은 멀티미디어 타입의 문서를 하이퍼미디어 문서 형식으로 변환할 수 있도록 확장하여 보완 개발될 수 있고, 장래에 전자 출판과 전자 도서관에 응용될 수 있다.

• Journal of Advanced Navigation Technology
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• v.19 no.6
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• pp.595-600
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• 2015

The implementation possibility of the flexible optical network configuration using the non-midway optical phase conjugator (OPC) in the dispersion-managed (DM) optical link for wavelength division multiplexed (WDM) transmission is demonstrated in this paper. It is confirmed that the implementation possibility of flexible link configuration is more increased, as number of fiber spans is more bigger and the residual dispersion per span (RDPS) is more large. It is also confirmed that the non-midway OPC link, in which RDPS of the latter half transmission section (after OPC) is decided by the averaged RDPS of the former half transmission section (before OPC), has more advantage for the flexible network configuration.

• Journal of Advanced Navigation Technology
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• v.13 no.1
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• pp.27-33
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• 2009

New optical transmission link techniques improving performance of WDM channels, each channel have bit rate of 40 Gbps, are proposed. The proposed optical link configuration consist of optical phase conjugator (OPC) placed at middle of total transmission length, and dispersion management (DM) as a role of compensating dispersion cumulated in transmission line. It is confirmed that Q-factor of total channels are improved by combining OPC and DM in optical transmission link as a result of following fact; DM not only mitigate the cumulated dispersion in total transmission line but also help OPC to compensate optical nonlinearities. And, it is confirmed that the improvement of Q-factor of overall WDM channels depends on net residual dispersion (NRD) of optical link.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11B
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• pp.1640-1650
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• 2010

To prepare for the network centric warfare, Korea Joint Tactical Data Link System(KJTDLS) has been developed by the South Korean military recently and its development is divided into two phases: basic and complete ones. Due to the limited bandwidth and low transmission efficiency of the developing KJTDLS (basic), lots of problems could be occurred when the TDMA protocol in Link-16 is applied. In this paper, a new dynamic TDMA frame structure for KJTDLS(basic) is proposed and the performance of the proposed is evaluated through the implementation of simulation.

• Journal of the Korean Society for Library and Information Science
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• v.37 no.2
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• pp.153-168
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• 2003

A hyperlink on academic World Wide Web has started to be recognized as a form of collaborative communication network connecting individual researchers and research groups and expanding their collaboration relations by making possible easy and direct online contact among people or groups anywhere in the world. This paper describes the structure of academic hyperlinks embedded in universities' Web sites hosted at the 10 Asian countries and further, examines the association between the structure of the hyperlink network and collaborative communication pattern among those countries based on their frequency of co-authoring articles. This research found that the number of inter-hyperlinks among universities' Web sites was significantly correlated with the frequency of co-authored articles across the 10 countries.