• Smart Structures and Systems
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• v.6 no.7
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• pp.851-866
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• 2010

This paper presents a new concept of using PZT (lead zircornate titanate) transducers as a non-destructive testing (NDT) tool for evaluating quality of concrete. Detection of defects in concrete is very important in order to check the integrity of concrete structures. The electro-mechanical impedance (EMI) response of PZT transducers bonded onto a concrete specimen can be used for evaluating local condition of the specimen. Measurements are carried out by electrically exciting the bonded PZT transducers at high frequency range and taking response measurements of the transducers. In this study, the compression test results showed that concrete specimens without sufficient compaction are likely to fall below the desired strength. In addition, the strength of concrete was greatly reduced as the voids in concrete were increased. It was found that the root mean square deviation (RMSD) values yielded between the EMI signatures for concrete specimens in dry and saturated states showed good agreement with the specimens' compressive strength and permeable voids. A quality metric was introduced for predicting the quality of concrete based on the dry-saturated state of concrete specimens. The simplicity of the method and the current development towards low cost and portable impedance measuring system, offer an advantage over other NDE methods for evaluating concrete quality.

• International Journal of Advanced Culture Technology
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• v.12 no.2
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• pp.167-179
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• 2024

This study addresses the challenge of objectively evaluating the performance of early-stage startups amidst limited information and uncertainty. Focusing on companies selected by TIPS, a leading private sector-driven startup support policy in Korea, the research develops a new indicator to assess technological efficiency. By analyzing various input and output variables collected from Crunchbase and KIND (Korea Investor's Network for Disclosure System) databases, including technology use metrics, patents, and Crunchbase rankings, the study derives technological efficiency for TIPS-selected startups. A prediction model is then developed utilizing machine learning techniques such as Random Forest and boosting (XGBoost) to classify startups into efficiency percentiles (10th, 30th, and 50th). The results indicate that prediction accuracy improves with higher percentiles based on the technical efficiency index, providing valuable insights for evaluating and predicting startup performance in early markets characterized by information scarcity and uncertainty. Future research directions should focus on assessing growth potential and sustainability using the developed classification and prediction models, aiding investors in making data-driven investment decisions and contributing to the development of the early startup ecosystem.

• Proceedings of the Technology Innovation Conference
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• 2003.02a
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• pp.101-119
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• 2003

Assessing the effectiveness of R&D organization is hampered by the lack of measurable goals and identifiable outcome criteria. In this review, key issues In evaluating effectiveness are identified and Insights on the application of major assessment approaches are provided. This paper presents System-Process Model on assessing the effectiveness of R&D organization(Korean Government-supported Research Institutes). System-Process Model has attempted to integrate different approaches. It is useful In sensitizing evaluators to the importance of goal, internal process, system resource and feedback in improving organizational effectiveness.

• Journal of Biomedical Engineering Research
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• v.9 no.2
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• pp.233-238
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• 1988

Human body sways continuously to maintain balance during upright stance. A computer-aided instrumentation system using a force platform has been developed to investigate the body balance. The Kistler force platform and amplifiers were only used to obtain the precise measurements, and the data acquisition and analysis software operating on an IBM PC with A/D converter was developed. This study presents methods for the display of platform center of pressure data on stability study. This system can be used as a tool in evaluating the man's ability to balance and disorders of the nervous system.

• Journal of the Ergonomics Society of Korea
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• v.15 no.1
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• pp.53-67
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• 1996

Since Romberg's test in 1953, the analysis of postural sway during upright stance has been widely used as a tool for evaluating balance and disorders of the postural control system. This review describes the methods that have been used to evaluste the static and dynamic performance of the postural control system. Various identification methods of postural control system based on standing balance are discussed and measures of postural sway are described. The application areas of standign balance research, with an emphasis on postural control evaluations, are also briefly described. This review can be used to gain an understanding of the dynamics of human standing balance.

• Journal of Korean Institute of Industrial Engineers
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• v.9 no.1
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• pp.33-43
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• 1983

This paper develops a general methodology for evaluating inspection (mainly, safety inspection) policies, standard and regulations in a complex system with lots of components. Based on practically available data, this methodology enable planners and regulators to estimate the costs and effectiveness of different inspection policies when applied under different system working conditions. As main tools, the concepts of detection probability and earliness of detection are developed in this paper.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1991.06a
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• pp.12-20
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• 1991

It is of great importance for any vessel under way especially in rough sea to be maneuvered safely with proper seakeeping performance. In this paper the author aims to develope a navigational safety evaluation system in rough sea by analysis and the theory of evaluating the seakeeping performance The author suggests a computer model of navigational safety evaluation system and examined the validity of the model by computer simulation.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.463-470
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• 1999

In this paper, a numerical method for evaluating the efficiency of vibration reduction of substructure under slab track is developed for optimal design of floating slab track. The equation of motion for train and track interaction system is derived by applying compatibility condition at the contact points between wheels and rails. The train is modelled by 3-masses system and the track by continuous support beam system. Numerical analyses are carried out to investigate the effect of train speed, stiffness and damping of slab-pad, and track irregularity upon vibration reduction in substructure under the track.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.1
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• pp.79-86
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• 2017

This research focused on deciding optimal manufacturing WIP (Work-In-Process) limit for a small production system. Reducing WIP leads to stable capacity, better manufacturing flow and decrease inventory. WIP is the one of the important issue, since it can affect manufacturing area, like productivity and line efficiency and bottlenecks in manufacturing process. Several approaches implemented in this research. First, two strategies applied to decide WIP limit. One is roulette wheel selection and the other one is elite strategy. Second, for each strategy, JIT (Just In Time), CONWIP (Constant WIP), Gated Max WIP System and CWIPL (Critical WIP Loops) system applied to find a best material flow mechanism. Therefore, pull control system is preferred to control production line efficiently. In the production line, the WIP limit has been decided based on mathematical models or expert's decision. However, due to the complexity of the process or increase of the variables, it is difficult to obtain optimal WIP limit. To obtain an optimal WIP limit, GA applied in each material control system. When evaluating the performance of the result, fitness function is used by reflecting WIP parameter. Elite strategy showed better performance than roulette wheel selection when evaluating fitness value. Elite strategy reach to the optimal WIP limit faster than roulette wheel selection and generation time is short. For this reason, this study proposes a fast and reliable method for determining the WIP level by applying genetic algorithm to pull system based production process. This research showed that this method could be applied to a more complex production system.

• The Research Journal of the Costume Culture
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• v.28 no.5
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• pp.705-718
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• 2020

The goal of this study was to develop a haptic communication system that can convey the tactile sensation of fashion materials in a virtual environment. In addition, the effectiveness and how realistically the virtual fabric image of this system delivers the tactile sensation of actual fabric was verified. First, a literature review was conducted through which the tactile attributes of fashion materials were defined that would be implemented in the haptic communication system. Then, a questionnaire for evaluating the tactile attributes of fashion materials was developed. Next, a haptic communication system was designed to convey fashion image experiences in a virtual environment, from which a haptic rendering model was suggested. The effectiveness of the haptic communication system was evaluated by verifying user experiences with questions developed through a user evaluation experiment. The validity of the evaluation questions pertaining to the tactile attributes and the effects of the haptic communication system were verified. Factor analysis was conducted to verify the evaluation of the tactile sense attributes of the fashion material, which identified density, thickness, and elasticity of the material as key factors. As a result of comparisons between the tactile sense through haptic characteristics and through touching, it was observed that regarding density and thickness, tactile sense experience led to greater perceived reality, while this was not the case for elasticity.