• Current Optics and Photonics
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• v.2 no.4
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• pp.308-314
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• 2018

Visible light communication (VLC) is considered a strong future candidate for indoor wireless communication. However, its performance seems to be relatively unsatisfactory when compared to wireless local area network (WLAN) communication using millimeter waves. To improve the performance of VLC, numerous technologies have been proposed so far, in both electrical and optical domains. Among the proposals, optical beamforming (OB) is an optical-domain technology that can concentrate light in a specific direction or on a target spot. It can significantly improve VLC performance and can be widely used, because it does not depend on electrical modulation schemes. Therefore, this review discusses the concept, principle, and types of OB, the structure of a VLC system using OB, performance results of OB, and the combination of OB with electrical signal modulation in VLC. OB is expected to be one of the key techniques in future VLC implementations, similar to radio-frequency beamforming in millimeter-wave communication.

• The Journal of Sustainable Design and Educational Environment Research
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• v.3 no.1
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• pp.46-59
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• 2003

In this study, analyzing class method, curriculum and demand performance of materials and user according to the 7th educational curriculum which, it is surveyed that materials design performance standards of floor and window suitable to future educational environment. Based on this study, It is needed for development of special materials suitable educational facilities, making standards fitting demand, study of variable and special field for educational facilities, study for security of objective data of materials, study of performance evaluation method subdivided, and desirable positive use of intimate environmental materials.

• Journal of KIBIM
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• v.8 no.4
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• pp.13-22
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• 2018

Future performance prediction of bridges is challenging task for structural engineers. Well-organized information from design, construction and operation stages is essential for the assessment of structures. Digital twin model is a new concept to realize more reliable data platform for management of infrastructures. Damage history including degradation of material, cracking, corrosion, etc. needs to be accumulated in the digital model. The digital model is linked to the analysis model for the assessment of structural performance considering changed mechanical properties of structural components. In this paper, initial definition digital twin model of a PSC-I girder bridge is proposed.

• Journal of the Korea Society for Simulation
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• v.26 no.2
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• pp.41-49
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• 2017

In the acquisition program, the conceptual design is the most important step toward specifying the military objectives, establishing requirements and determining future developmental directions, of a target system. However, if both the requirements and directions are incorrectly set due to the lack of development experiences and literature backgrounds in the target systems, such as future ground combat vehicles, it may become a major risk in the future design phases and the entire acquisition program. In order to correct these errors in the future phases, time, effort and cost are required. Therefore, it is necessary to reduce the errors that occur in the initial stages to effectively acquire the future ground combat vehicles. This paper describes the initial design method for verifying the requirements and the developmental directions and estimating the system performance at the conceptual design through the system-level physical modeling and simulation (M&S) and the target system performance analysis. The system-level physical M&S use cutting-edge design tools, model-based designs and geometric-based designs. The system performance estimation is driven from the results of the system-level physical M&S and the specialized system analysis software.

• 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.

• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.3
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• pp.21-37
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• 2001

Riding on the wave of the information technology revolution, a slow of internet venture businesses (IVB) came into being. Hence, one of the recent developments in Korean capital market has been the proliferation of IVB, which is in accordance with the worldwide trend of ‘new economy’. Although the fair valuation is crucial for the nourishment of IVB, it is difficult to apply traditional valuation methods to these firms without reservation. It is due to the facts that most venture firms have little records of performance, grow unprecedently fast, and have highly uncertain future. The main purpose of this study is to suggest performance evaluation system of IVB and to develop KPE (Key Performance Indicators). Our empirical study is based upon Kaplan & Norton’s Balance Scorecard (BSC) approach. Specifically, our research has been conducted by the following two subsequent procedures: Firstly, seven internet venture firms have been selected and their executives have been interviewed by FGI(Focus Group Interview) method. Based upon these results, performance indicators have been developed. Secondly, by using the above mentioned BSC items (i.e., financial perspective, customer perspective, internal perspective and innovation & learning perspective), questionnaires have been constructed and sent to IVB through e-mail as well as over the Fax. Among the collected 110 samples, reliable 106 samples have been used to build BSC model and to draw our conclusion. In the future study, it would be much better to consider the role of strategy in IVB and the causal relationship among Key Performance Indicators of BSC.

• Korean Journal of Computational Design and Engineering
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• v.20 no.3
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• pp.221-229
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• 2015

M&S (Modeling & Simulation) based design is widely accepted for the development of the future weapon system with better performance in a cheaper and faster way. Integrated simulation environment (ISE) is needed for the M&S based design. On the ISE, system engineers can not only verify design options but also validate system requirements. In this paper, we propose architectural models of the integrated simulation environment (ISE) which incorporates mission effectiveness M&S (Modeling & Simulation), system performance M&S, the optimization model of integrated performances, digital mockup and virtual prototype. The ISE architectural models may be used to implement the ISE for the development of the future unmanned ground combat vehicle.

• ETRI Journal
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• v.36 no.3
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• pp.490-497
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• 2014

The market performance of WiBro in Korea has not been as expected, and its rapid diffusion in the near future is unlikely owing to the existence of competing services. There has been little research on the factors affecting this low market diffusion. This study is based on an analytical framework in which a lack of service capability and the insufficiency of service-related activities have resulted in the current poor market performance. An expert survey was conducted on WiBro specialists and verified using the analytical hierarchy process method. The result of this analysis is as follows: underinvestment in network deployment and marketing, insufficient promotional policies, and a shortage of service capabilities are to be analyzed as the main causes of WiBro's low market diffusion.

• Journal of Aerospace System Engineering
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• v.9 no.2
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• pp.47-50
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• 2015

MSIP(Ministry of Science, ICT and Future Plaaning) established the 'space technology commercialization plan' at 2012. According to this plan, MSIP and KARI(Korea Aerospace Research Institute) are nuturing space-related venture companies so that those companies are increasing from 2013. In addition, MSIP and KARI held space-related idea festivals last two years, and will run start-up program (STAR-Exploration) this year.

• Structural Monitoring and Maintenance
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• v.2 no.1
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• pp.49-64
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• 2015

This paper presents a method for assessing the risk of wave run-up and overtopping of existing coastal defences and for analysing the probability of failure of the structures under future hydraulic conditions. The recent UK climate projections are employed in the investigations of the influence of changing environments on the long-term performance of sea defences. In order to reduce the risk of wave run-up and overtopping caused by rising sea level and to maintain the present-day allowances for wave run-up height and overtopping discharge, the future necessary increase in crest level of existing structures is investigated. Various critical failure mechanisms are considered for reliability analysis, i.e., erosion of crest by wave overtopping, failure of seaside revetment, and internal erosions within earth sea dykes. The time-dependent reliability of sea dykes is analysed to give probability of failure with time. The results for an example earth dyke section show that the necessary increase in crest level is approximately double of sea level rise to maintain the current allowances. The probability of failure for various failure modes of the earth dyke has a significant increase with time under future hydraulic conditions.