• Journal of Technology Innovation
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• v.16 no.2
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• pp.17-40
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• 2008

The collaboration among academia, industry, and public research sector gains importance in these days. This is essential for implement competent regional and national innovation systems. There have been many governmental programs for activating collaboration among innovation actors. Most policy programs for collaboration have aimed at increasing S&T and innovation potential and constructing S&T infrastructure. However, Korea has not produced a sufficient level of collaboration, especially on regional level. Most policy programs could not reach regions and many regions have no enough innovation actors. In order to activate R&D collaboration, therefore, we suggest that Korean S&T community should build and implement "collaborative research centers" all over the regions. This concept is very new approach, especially because it focuses on collaboration among regional innovation actors. In this paper, we discuss a concept, type, and execution strategy of collaboration research centers. We expect that these centers will play an important role in implementing successful regional innovation systems, as they will link regional innovation actors very closely.

• The Journal of Korea Robotics Society
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• v.8 no.1
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• pp.8-19
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• 2013

One of the important issues for structural and electrical specifications in developing a robot is to determine lengths of links and motor specifications, which need to be appropriate to the purpose of robot. These issues become more critical for a gait rehabilitation robot, since a patient wears the robot. Prior to developing an entire gait rehabilitation robot, designing of a 1DOF assistive knee joint of the robot is considered in this paper. Human gait motions were used to determine an allowable range of knee joint that was rotated with a linear type actuator (ball-screw type) and links. The lengths of each link were determined by using an optimization process, minimizing the stroke of actuator and the total energy (kinetic and potential energy). Kinetic analysis was performed in order to determine maximum rotational speed and maximum torque of the motor for tracking gait trajectory properly. The prototype of 1 DOF assistive knee joint was built and examined with a impedance controller.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.3775-3788
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• 2014

With the increasing number of the wireless and mobile networks, the way that people use the Internet has changed substantively. Wireless multimedia services, such as wireless video streaming, mobile video game, and mobile voice over IP, will become the main applications of the future wireless Internet. To accommodate the growing volume of wireless data traffic and multimedia services, cognitive radio (CR) and Information-Centric Network (ICN) have been proposed to maximize the utilization of wireless spectrum and improve the network performance. Although CR and ICN have high potential significance for the future wireless Internet, few studies have been conducted on collaborative operations of CR and ICN. Due to the lack of infrastructure support in multi-hop ad hoc CR networks, the problem is more challenging for video streaming services. In this paper, we propose a Cross-layer Video Streaming Mechanism (CLISM) for Cognitive Radio Ad Hoc Information Centric Networks (CRAH-ICNs). The CLISM included two distributed schemes which are designed for the forwarding nodes and receiving nodes in CRAH-ICNs. With the cross-layer approach, the CLISM is able to self-adapt the variation of the link conditions without the central network controller. Experimental results demonstrate that the proposed CLISM efficiently adjust video transmission policy under various network conditions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.171-172
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• 2018

Performance measurement and management in the construction industry has traditionally been regarded as the major factor for successful business execution. In addition, there is emphasis on the function of performance measurement and management that can early warn potential risks and poor performance in project execution environment changes. Previous studies have made various attempts to measure the quantitative performance of construction projects, and the research to derive the link between the results and the issue that can meet the future needs is expected to provide valuable information. The purpose of this study is to analyze the research trends based on the keywords presented in previous studies on the performance measurement and management of construction projects. Considering that the results presented in the existing literature can be an indicator of the evolution of the sector before it is applied to industry, the result of this study is expected to be used as a basic data to support the establishment of research direction in the future.

• The Korean Journal of Rehabilitation Nursing
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• v.19 no.2
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• pp.100-107
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• 2016

Purpose: The goal of this study was to examine the association between perceived racial discrimination and substance use and the potential moderating effect of perceived parental affection between the two variables. Methods: A total of 101 Korean American adolescents participated in this cross-sectional study utilized an online survey. Descriptive statistics were used to describe for means and frequencies and the patterns of substance use. Logistic regression analysis was also used to examine the association between perceived discrimination and substance use. Results: Ninety percent of the participants reported perceiving racial discrimination, and 21% had used at least one kind of substance in the month prior to taking the survey. The most frequently used substance was alcohol, followed by marijuana and tobacco products. Logistic regression analysis revealed a link between perceived racial discrimination and substance use (OR = 1.74, 95% CI = 1.01, 3.00). However, parental affection did not moderate between racial discrimination and substance use. Conclusion: These findings suggest that perceived racial discrimination is positively associated with substance use among Korean American adolescents, and health care providers, counselors, and school nurses should screen for discrimination-related stress and substance use in this population.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.12
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• pp.561-569
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• 2006

Because of the trend of deregulation, power industry is going through an unprecedented transformation in North America and Europe, and there are a host of acquisitions and mergers by the private sector to position themselves to take advantage of new business opportunities. Deregulation has accelerated the development of smaller generators and fuel cells will gradually become more attractive to mainstream electricity users as they improve in capability and decrease in cost. Fuel Cell technology is surveyed and the potential of using fuel cell as a distributed generation source is presented. This paper recommends the fuel cell power plants as alternative energy sources for distributed generation in Jeju Island, Korea. This will help in increasing fuel efficiency, at least double the current thermal plants', increasing the reliability of power supply, reducing the dependency on the HVDC link, providing quality power to the growing infrastructure, and maintaining clean air in meeting the free-trade international island.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.1905-1907
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• 1998

The multi-level approach seems to be best suited to high power, high voltage ac drives with low torque ripple and fast dynamic response. If high control performance is required, space vector control becomes desirable, and the task becomes time critical. In this paper, a simplified space vector PWM method for the control of a three level inverter is proposed. As the PWM is simple in structure, it is easy to implement and the fluctuation of the neutral point potential of DC link can be supressed effectively. The simulation results demonstrate that the proposed PWM strategy can be applied to high power, high voltage inverter systems. And its application to multi-level inverter is easily done on the same principle.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.2
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• pp.145-151
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• 2005

Cheju-Haenam HVDC link transmits electrical power up to 300[MW] Because of its size, HVDC system has a great potential for damping power system oscillations. This paper with the frequency control of the KEPCO HVDC system linking Haenam to Cheju island. Frequency control at Cheju island ensures that the island AC system frequency is maintained Performance are evaluated using a reduced Cheju network and a detailed model of the fm system modelled in the PST software. Transient oscillations for the 3 phase fault carried out with HVDC frequency control are well damped as the control parameters have been adjusted.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.4
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• pp.451-462
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• 2016

Photovoltaic energy conversion becomes main focus of many researches due to its promising potential as source for future electricity and has many advantages than the other alternative energy sources like wind, solar, ocean, biomass, geothermal etc. In Photovoltaic power generation multilevel inverters play a vital role in power conversion. The three different topologies, diode-clamped (neutral-point clamped) inverter, capacitor-clamped (flying capacitor) inverter and cascaded h-bridge multilevel inverter are widely used in these multilevel inverters. Among the three topologies, cascaded h-bridge multilevel inverter is more suitable for photovoltaic applications since each pv array can act as a separate dc source for each h-bridge module. This paper presents a single phase Cascaded H-bridge five level inverter for grid-connected photovoltaic application using sinusoidal pulse width modulation technique. This inverter output voltage waveform reduces the harmonics in the generated current and the filtering effort at the input. The control strategy allows the independent control of each dc-link voltages and tracks the maximum power point of PV strings. This topology can inject to the grid sinusoidal input currents with unity power factor and achieves low harmonic distortion. A PID control algorithm is implemented in Arm Processor LPC2148. The validity of the proposed inverter is verified through simulation and is implemented in a single phase 100W prototype. The results of hardware are compared with simulation results. The proposed system offers improved performance over conventional three level inverter in terms of THD.

• Journal of the Korean Geotechnical Society
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• v.29 no.11
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• pp.49-60
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• 2013

The plan for major design-build projects of railway link among countries in gulf area (GCC) and freight rail construction is recently announced, but Korean companies have a hard time tendering due to special geotechnical condition in the Middle East. The major geotechnical risks during railway construction in the Middle East are related to ground improvement of soft Sabkha ground, wind-blown sand mitigation measure, dune sand compaction, and construction of large-scale cut and embankment. In this study, the characteristics of special geotechnical condition and potential geotechnical risks during railway construction in the Middle East are discussed on the basis of field observation, literature review, and field and laboratory test results.