• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.2
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• pp.162-170
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• 2009

As one of promising solutions to overcome high oil price and energy crisis, the construction market of high value-added LNG plants is spotlighted world widely. The purpose of this manuscript is to introduce domestic activities to develop risk assessment technology against overseas monopolization. After analyzing relevant specific features and their technical levels, risk assessment program, non-destructive reliability evaluation strategy and safety criteria unification class are derived as core technologies. These IT-based convergence technologies can be used for enhancement of LNG plant efficiency, in which the modular parts are related to a system with artificial optimized algorithms as well as diverse databases of facility inspection and diagnosis fields.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.6
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• pp.550-557
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• 2015

The Jeju Special Self-Governing Province is currently promoting the "Carbon-free Island by 2030" policy, which requires the use of renewable energy instead of fossil fuel so that the island will have no carbon gases generated by 2030. To implement this policy, the island plans to build a wind power plant capacity of 1.09 GW in 2020; this wind power plant is currently ongoing. However, when wind power output is greater than the power demand of the island, the stability of Jeju Island power system must be prepared for it because it can be a problem. Therefore, this study proposes a voltage source-type MMC-HVDC system linked to mainland Korea to expand the wind power penetration limits of Jeju Island under the stable operation of the Jeju Island power system. To verify the effectiveness of the proposed scheme, computer simulations using the PSCAD/EMTDC program are conducted, and the results are demonstrated. The scenarios of the computer simulation consist of two cases. First, the MMC-HVDC system is operated under variable wind power in the Jeju Island power system. Second, it is operated under the predicted Jeju Island power system in 2020.

• Nuclear Engineering and Technology
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• v.41 no.6
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• pp.785-796
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• 2009

A KALIMER-600 concept which is a type of sodium-cooled fast reactor, has been developed at KAERI. It uses sodium as a primary coolant and is a pool-type reactor to enhance safety. Also, a supercritical carbon dioxide ($CO_2$) Brayton cycle is considered as an alternative to an energy conversion system to eliminate the sodium water reaction and to improve efficiency. In this study, a simplified model for analyzing the thermodynamic performance of the KALIMER-600 coupled with a supercritical $CO_2$ Brayton cycle was developed. To develop the analysis model, a commercial modular modeling system (MMS) was adopted as a base engine, which was developed by nHance Technology in USA. It has a convenient graphical user interface and many component modules to model the plant. A new user library for thermodynamic properties of sodium and supercritical $CO_2$ was developed and attached to the MMS. In addition, some component modules in the MMS were modified to be appropriate for analysis of the KALIMER-600 coupled with the supercritical $CO_2$ cycle. Then, a simplified performance analysis code was developed by modeling the KALIMER-600 plant with the modified MMS. After evaluating the developed code with each component data and a steady state of the plant, a simple power reduction and recovery event was evaluated. The results showed an achievable capability for a performance analysis code. The developed code will be used to develop the operational strategy and some control logics for the operation of the KALIMER-600 with a supercritical $CO_2$ Brayton cycle after further studies of analyzing various operational events.

• Journal of The Korea Institute of Healthcare Architecture
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• v.25 no.2
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• pp.51-62
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• 2019

Purpose: This study aims to examine spatial characteristics of ambulatory care department Chronologically through case studies; and to consider the social implication of these spatial changes. Methods: In this study, a total of eight ambulatory care departments, one or two for each period, were selected in order to analyze the spatial characteristics. Results: First, since the 1990s, the outpatient department of the US has been changed into a patient-centered space by providing high quality outpatient medical services through individual exam room planning. Second, the exam room has been changed from open/semi-open/group exam room to individual exam room since 1990, and the trend is shifting from the cluster type to the modular type consisting of universal exam rooms in order to achieve the flexibility of exam room. Third, the diagnostic/testing area has been deployed to the ambulatory clinic to enable 'one-stop shopping' for patients-centered care since 1990s, however, it has been disappearing since 2000 due to Reduce medical expenses. Fourth, the Central Nursing Station type first appeared in the outpatient department In the 2000s, followed by the type of decentralized nursing station type since 2010s. And fifth, the area of medical support has been placing to be concentrated on one place due to the Lean Design strategy since 2010. Implications: In the future, it is expected that Korea will be more focused on efficiency, visual control, and flexibility in the planning of the ambulatory care department as in the case of the United States.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.1
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• pp.26-32
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• 2022

This paper proposes a power system that includes a 120k W fuel cell DC-DC converter (FDC) and 30 kW bidirectional DC-DC converter (BHDC) for a 150 kW fuel-cell vehicle. With a high DC link voltage of 800 V, the efficiency and power density of the power electronic components are improved. Through the modular design of FDC and BHDC, electric components are shared, resulting in reduced mass production costs. The switching frequency of 30 kHz of full SiC devices and optimal design of coupled inductor reduce the volume, achieving a power density of 8.3 kW/L. Furthermore, a synergetic operation strategy using variable limiter control of FDC and BHDC was proposed to efficiently operate the fuel cell vehicle considering the fuel cell stack efficiency according to the load. Finally, the performance of the prototype was verified by Highway Fuel Economy Driving Schedule testing, EMI test, and the linked operation between FDC and BHDC. The full load efficiencies of the FDC and BHDC prototypes are 98.47% and 98.74%, respectively.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.4
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• pp.315-333
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• 2021

Due to the Global Navigation Satellite System (GNSS) modernization, recently launched GNSS satellites transmit signals at various frequency bands such as L1, L2 and L5. Considering the Korean Positioning System (KPS) signal and other GNSS augmentation signals in the future, there is a high probability of applying more complex communication techniques to the new GNSS signals. For the reason, GNSS receivers based on flexible Software Defined Radio (SDR) concept needs to be developed to evaluate various experimental communication techniques by accessing each signal processing module in detail. This paper proposes a novel SDR-based A-GNSS receiver capable of processing multi-GNSS/RNSS signals at multi-frequency bands. Due to the modular structure, the proposed receiver has high flexibility and expandability. For real-time implementation, A-GNSS server software is designed to provide immediate delivery of satellite ephemeris data on demand. Due to the sampling bandwidth limitation of RF front-ends, multiple SDRs are considered to process the multi-GNSS/RNSS multi-frequency signals simultaneously. To avoid the overflow problem of sampled RF data, an efficient memory buffer management strategy was considered. To collect and process the multi-GNSS/RNSS multi-frequency signals in real-time, the proposed SDR A-GNSS receiver utilizes multiple threads implemented on a CPU and multiple NVIDIA CUDA GPGPUs for parallel processing. To evaluate the performance of the proposed SDR A-GNSS receiver, several experiments were performed with field collected data. By the experiments, it was shown that A-GNSS requirements can be satisfied sufficiently utilizing only milliseconds samples. The continuous signal tracking performance was also confirmed with the hundreds of milliseconds data for multi-GNSS/RNSS multi-frequency signals and with the ten-seconds data for multi-GNSS/RNSS single-frequency signals.

• Journal of Engineering Education Research
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• v.11 no.3
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• pp.5-11
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• 2008

Far greater than ever before is the present industrial demand for skilled professionals in innovative product design and development. Yet there is an apparent lack of a sufficient curricular provision for training design professionals in almost all engineering schools. The present study is to propose a systematic procedure for developing a strategy for building an innovative product design curriculum and demonstrate its application. The procedure consists of three major steps: strategic element derivation, task formulation, and task execution roadmap construction. The proposed procedure was applied to develop a modular curriculum (a cluster of several related courses) covering various subjects in relation to innovative product design and development. The procedure seems quite effective and useful for developing a curriculum that is strategically well differentiated based on the unique characteristics of a particular educational institute and its applicability seems not limited to a specific domain.

• Journal of KIISE:Software and Applications
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• v.31 no.3
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• pp.255-266
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• 2004

In the Web-based information systems, separating the business process logic from the data and presentation logic brings about a wide range of advantages. However, this separation is not easily achieved; even the data logic may be not separated from the presentation layer. So, it requires to define an model for business processes, and then to map the model into the user's dynamic interface using the logic separating strategy. This paper presents a stylesheet method to recognize the process by extending XSLT (Extensible Stylesheet Language Transformations), in order to achieve the logic separation. To do this, it provides an specification of the business process, and a scheme that extracts business model factors and their interactions using a Petri-net notation to show the business model into the process point of view. This is an attempt to separate users' interaction from the business process, that is, dynamic components of interaction Web document from the process structure of Web applications. Our architecture consist mainly of an XSLT controller that is extended by a process control component. The XSLT controller is responsible for receiving the user requests and searching the relevant templet rule related to different user requests one by one. Separation of concerns facilities the development of service-oriented Web sites by making if modular. As a result, the development of service-oriented Web sites would be very easy, and can be changed without affecting the other modules, by virtue of the modularization concept. So, it is easy to develop and maintain the Web applications in independent manner.