• Journal of the Korean BIBLIA Society for library and Information Science
• /
• v.10 no.1
• /
• pp.213-222
• /
• 1999

The purpose of this study is to identify important web pages in a particular area The basic premise is that citation analysis can show a similar relationship among different web pages. Web pages about‘weather’were found using a search engine Each web page was examined by hyperlink from other web pases and/or to other web pages. After this process, seven web pases are linked by many web pages. Seven web pages were analyzed by co-citation analysis. The result shows that selected web pages are linked by characteristics of information provided.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.10a
• /
• pp.607-608
• /
• 2013

무선 애드훅 네트워크에서는 무선링크의 성능을 표현하는 다양한 품질 척도가 있다. 그것은 노드가 움직임이 없는 상태에서 주변 무선 상태를 반영한다. 하지만 해상 환경에서는 선박의 이동성 뿐만 아니라 바람과 파고에 의해 선박이 움직이는 특성이 있다. 따라서 선박에 위치한 안테나의 흔들림을 유발하여 신호의 수신을 불안정하게 만든다. 본 논문은 선체운동에 따른 무선 링크 성능을 분석한다. 이를 위해 자이로 센서를 이용하여 서로 다른 해상 환경에서 선체운동을 측정 및 분석하고, 하드웨어 및 소프트웨어에 의한 무선 링크 안정화 방안을 제시한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.1
• /
• pp.42-49
• /
• 2011

Telemetry link requires high data rate to transmit the multimedia data for lunar explorations in space communications. In this paper, we analyze a data rate with the modulation and channel coding schemes based on Consultative Committee for Space Data Systems (CCSDS) in S, X, Ku and Ka bands, respectively. Then, we suggests modulation and channel coding schemes to meet the link margins and have a maximum data rate for lunar explorations in telemetry links.

• Proceedings of the KIPE Conference
• /
• 2017.07a
• /
• pp.200-201
• /
• 2017

무선전력전송 시스템의 전력 수신부는 많은 경우 송신부에 비해 크기가 작으므로 자계결합 에너지링크 코일의 권선을 비대칭으로 설계할 필요가 있다. 본 논문은 직렬 공진 보상 구조의 자계결합 무선전력전송에서 에너지링크 전압이득과 전력전송효율을 동시에 고려해 전력변환회로 관점에서의 비대칭 코일의 도식적인 분석 및 설계 방법을 제안한다. 제안하는 설계평면을 통해 에너지링크 코일의 정렬이 어긋날 때 혹은 부하요구가 변할 때 에너지링크의 전압이득과 전력전송효율 변화를 직관적으로 예측할 수 있으며 주어진 설계조건에 따라 에너지 링크를 간단히 설계할 수 있다. 본 제안방법은 회로 시뮬레이션을 통해 검증 되었다.

• The Journal of the Convergence on Culture Technology
• /
• v.7 no.1
• /
• pp.539-544
• /
• 2021

The tactical data link is a military data network to improve the ability to recognize battlefield situations. The ROK military is promoting the tactical data link performance improvement programs. Tactical data link is essential to combine and integrate various platforms, sensor data, and command and control (C2) systems. Therefore, the research on related technical fields is required. However, the tactical data link has not disclosed detailed technical information due to the characteristics of military operation. In this paper, we propose a data-based automated analysis methodology using intellectual property information to understand the technology trend of tactical data link. In this paper, data related to intellectual property is automatically collected and pre-processed, and analyzed in terms of time series. In addition, the current status of each institution of patent technology information was generated, and the process of identifying key-researchers through network analysis was presented with providing results of our approach in this paper.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.36S no.8
• /
• pp.17-29
• /
• 1999

Inter-Satellite Links(ISL) technique in the Polar Orbit Satellite plays the key role in the communication methods in IRIDIUM system, where the ISL is commonly established between neighbor satellites. The system has major drawbacks in maintaining the multi-hopping link connectivities while the satellite nodes are communicating each other. The proposed system is newly designed to allow diagonal link connections between the satellites and shows how it does improve the performance. The optimized number of satellites in the terms of their altitudes and visible distance are calculated. The traffic parameters and the probability of blocking are analyzed to compare the visible satellite link method with the neighbor link method mathermatically.

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

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.8B
• /
• pp.1341-1347
• /
• 2000

For the DRT satellite transponder system, BER and total SNR to be required in the earth terminal are evaluated under the condition of HPA nonlinearity in the FBJ(full-band jamming) or PBJ(partial-band jamming) of uplink and downlink. In case that the satellite Inter bandwidth( Ws) is same to the earth terminal bandwidth($W_r$),in conditions of uplink JSR 10[dB], downlink JSR 10[dB] and processing gain 30[dB], linear transponder system shows that uplink SNR needs to be 14.2[dB] to achieve the total SNR 10[dB] requirement in downlink SNR 14[dB]. However, Nonlinear transponder system with OBO(output backoff) 2[dB] requires 20.1 [dB] uplink SNR. From the above results, the nonlinearity of HPA in the satellite transponder causes the degradation of BER performance so that it is of interest to consider the power increase.

• Journal of Information Management
• /
• v.43 no.4
• /
• pp.119-142
• /
• 2012

This study analyzed the characteristics of hyperlink service from news articles in chosun.com and washington Post sites. The study showed that the Washington Post revealed many hyperlink-related elements and an increase in interactivity while Chosun.com was not established consistent hyperlink service. Also, this study analyzed news distribution based on genre, as a result, the life section was occupied the highest proportion with 32.4% for Chosun.com, while the news sections were evenly distributed for the Washington Post. Finally, as a result of classifying the linked words into 3 categories(Informational, navigational, and transactional), the highest contents category in both Chosun.com and Washington Post turned out to be informational words. Theses results can be used to develop and provide the effective link service of news articles in internet newspaper sites.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.6A
• /
• pp.563-574
• /
• 2006

This paper implements SCM(Spatial Channel Model), a kind of ray-tracing method which has characteristics similar to realistic wave propagation environments, for link-level performance analysis of OFDM(Orthogonal Frequency Division Multiplexing) based multiple antenna systems. The SCM is proposed by 3GPP & 3GPP2 Spatial Channel AHG(Ad-hoc Group) for system-level performance validation. In this paper, we modify the system level parameters and channel coefficient of SCM to compare the link-level performances of OFDM based multiple antenna systems. Through computer simulations, we manifest the implemented SCM channel characteristics. We analyze a realistic link-level performance of OFDM based conventional MIMO(Multiple Input Multiple Output) system and smart antenna system in the implemented channel. We also include the link-level performance of OFDM based multiple antenna systems in I-METRA(Intelligent Multi Element Transmit and Receive Antenna) and independent channel environments with the same system parameters. We suggest appropriate multiple antenna system in the given environment by comparing the link-level performance in the spatial channels that have different channel correlation values.