• Journal of the Korean Society for Library and Information Science
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• v.40 no.3
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• pp.191-214
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• 2006

Recently, some bibliometric researchers tried to use the centrality analysis methods and the centrality measures which are standard tools in social network analysis. However the traditional centrality measures originated from social network analysis could not deal with weighted networks such as co-citation networks. In this study. new centrality measures for analyzing bibliometric networks with link weights are suggested and applied to three real network data, including an author co-citation network, a co-word network, and a website co-link network. The results of centrality analyses in these three cases can be regarded as Promising the usefulness of suggested centrality measures, especially in analyzing the Position and influence of each node in a bibliometric network.

• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.2
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• pp.150-155
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• 2008

This paper is related to developing new Bit Error Rate (BER) simulator, Sam sung BER simulator (SBERS), in order to evaluate the link compliance and all kinds of effects of link compliance in a real environment. SBERS allows to generate transmit pulse accurately by using the various parameters, and obtain the eye diagram and bathtub curve, which represents the performance of link, by calculating the transmit pulse and the measured frequency response characteristics. SBERS give results as same as real environment after taking account of distribution and value of noise. To verify the accuracy of simulator, we derive the simulated and measured result and compare eye opening. The difference came out to be within 5% error. It is possible to estimate the real environment and design the transmitter and receiver circuit effectively using new BER simulator, SBERS.

• Journal of the Korean Society for information Management
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• v.25 no.2
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• pp.167-181
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• 2008

In this study, web link analysis of the Korean National Archives has been Performed using LexiURL to show the dynamic web flow of the National Archives and to identify which closely related institutions the archives should seek to cooperate with for developing an institutional strategic plan. Inlink and co-inlink analysis were performed and, to identify related institutions of the Korean National Archives. a comparison was made with other countries such as Australia, England and the United Stats. Through web link analysis, several features can be detected and future directions are suggested. Most inlinks and co-inlink of the Korean National Archives were from public institutions, indicating that relationships with educational or research institutions are weak. Moreover, Korean National Archives involve fewer web links related to international activities than other countries. Proceeding from these results, educational function, research function and international activities should be fortified. Korean National Archives need to provide more materials for supporting educational and research activities and more cultural interchange among related institutions. Further research with different heritage institutions such as libraries or museums is needed.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.1944-1953
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• 2014

This paper shows the design and control methods of the bidirectional DC-DC converter to generate the proper DC-link voltage of a PMSM drive. Conventionally, because the controllable power of the PWM based voltage source inverter is limited by its DC-link voltage, the DC-DC converter is used for boosted DC-link voltage if the inverter source cannot generate enough operating voltage for the PMSM drive. In this paper, to obtain more utilization of this DC-DC converter, optimal DC-link voltage control for PMSM drive will be explained. First, the process and current path of the DC-DC converter will be illustrated, and a control method of this converter for variable DC-link voltage will then be explained. Finally, an improvement analysis of the optimal DC-link voltage control method, especially on the deadtime effect, will be explained. The DC-DC converter of the proposed control method is verified by the experiments by comparing with the conventional constant voltage control method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1574-1580
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• 2021

This paper designs and presents the results of an air network simulation radio transmission link applied with a multi-beam active phase array antenna simulator in a testbed system for verifying an air network currently underway as a technology development task. Using the Ku band, the Radio transmission link was designed in consideration of the link budget to satisfy the requirements for the system being developed. Considering short-distance links and long-distance links, the required EIRP and G/T performance scales of multi-beam repeaters and mission planes were applied to confirm the minimum and maximum link margins based on Eb/No. In this Radio Transmission Link design, the application analysis results such as rainfall availability are used to effectively establish standards when selecting the operating radius of the multi-beam relay system and related system standards.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.83-86
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• 2019

This study proposes a methodology for predicting co-authorship of contributors to a highly anticipated paper through link analysis and learning, taking into account the result of collaborative research. Previous studies predict the co-authorship with high accuracy, but this shows limitations in that the quality of the predicted relationship is not considered. Therefore, to solve the above problem, we propose three steps to predict the co-authorship that will help with the expected performance: (1) Construct a heterogeneous graph to measure results of collaborative research. (2) Analyze and learn links based on results of collaborative research. (3) Predict links that are anticipated to have high expectation. It is expected to be useful for increasing confidence in the predicted co-authorship.

• Journal of Power Electronics
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• v.2 no.3
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• pp.181-188
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• 2002

The utility interfaced sinewave modulation Inverter for the solar photovoltaic power conditioner with a high frequency transformer is presented for residential applications. As compared with the conventional full-bridge hard switching slnewave PWM inverter with a high frequency link, the simplest single-ended edge-resonant soft switching sinewave inverter with a sinewave duty cycle pulse control scheme is implemented, resulting in size and weight reduction, low cost and high efficiency This paper presents a prototype system of the sinewave zero voltage soft switching sinewave inverter for solar power conditioner, along with its operating principle and unique features. In addition to these, this paper discusses a control implementation to deliver high quality output current. Major design of each component and the power loss analysis under actual power processing is also discussed and evaluated from an experimental point of view A newly developed utility-connected sinewave power conditioning circuit which achieves 92.5% efficiency under 4kW output is demonstrated.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.9
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• pp.3412-3431
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• 2015

This paper considers the effect of co-channel interference on hybrid satellite-terrestrial relay network. In particular, we investigate the problem of amplify-and-forward (AF) relaying in hybrid satellite-terrestrial link, where the relay is interfered by multiple co-channel interferers. The direct link between satellite and terrestrial destination is not available due to masking by surroundings. The destination node can only receive signals from satellite with the assistance of a relay node situated at ground. The satellite-relay link is assumed to follow the shadowed Rice fading, while the channels of interferer-relay and relay-destination links experience Nakagami-m fading. For the considered AF relaying scheme, we first derive the analytical expression for the moment generating function (MGF) of the output signal-to-interference-plus-noise ratio (SINR). Then, we use the obtained MGF to derive the average symbol error rate (SER) of the considered scenario for M-ary phase shift keying (M-PSK) constellation under these generalized fading channels.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.3
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• pp.422-429
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• 2022

In this paper, the intermediate frequency transmission signal level between the network system-based baseband and RF unit consisting of multi-channel airborne relay devices and a lot of mission devices, which are currently undergoing technology development tasks, is kept constant at the reference signal level. Considering the other party's receiving input range, despite changes in the short-range long-range wireless communication environment, it presents a multi-link protection and MLP-A algorithm that allows signals to be transmitted stably and reliably through signal detection automatic gain control, and experiments and analysis considering short-distance and long-distance wireless environments were performed by designing, manufacturing, and implementing RF units to which MLP-A algorithms were applied, and applying distance calculation equations to the configuration of multiple air movements and verification networks. Through this, it was confirmed that a stable and reliable RF communication system can be operated.

• Knowledge Management Research
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• v.15 no.2
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• pp.129-145
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• 2014

As a community of practice (CoP) is known to facilitate team learning, it is increasingly important to understand the mechanisms of CoP, thereby enabling organizations to fully utilize it and optimize its benefits. To explain how CoP improves organizational performance, we focus on its effects on social capital and knowledge management activities, and propose a research model suggesting that shared goals and trust in CoP improve its performance through knowledge integration. Our analysis uses structural equation modeling, with field data collected from 372 members of 46 CoPs in three companies; the analysis validates our research model. Our findings also suggest that CoP diversity can strengthen the link between knowledge integration and CoP performance.