• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2471-2474
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• 2003

This paper focuses on the stability and operability of a man-machine system considering a human operator. Some papers' main interest has been the stability only, but the operability such as fatigue is also the other main interest. In a man-machine system, feelings such as motional, visual, and kinesthetic are important since those enable operators to work easily or fatigue operators. A model of a man-machine system has been developed. Motional, visual, and kinesthetic feelings may be considered as feedbacked sensor signals. We also have quantified the degree of fatigue with respect to reference operation. This is a performance index to be optimized. Several methods are presented to optimize the degree of fatigue and the stability of the integrated system. Examples are presented to show that the usefulness of the proposed modeling method and fatigue mitigating algorithm.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.478-492
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• 2021

In this study, hull dimensions of an FPSO were optimized to maximize its operability at Brazil field. In contrast with the previous works which have used simplified models to evaluate some indicators related to stability and hydrodynamic performances of FPSOs for its own optimal design, we developed a generic hull and compartment modeler and sophisticated stability and hydrodynamic calculation modules. With the aid of the developed tools, the hull optimization was performed with initial dimensions of an FPSO originally designed for west Africa field. The optimization results indicated the relative importance of hydrodynamic performances compared with stability performances for the FPSO hull dimensioning by showing that there were 3 active constraints related to them, which were the natural periods of heave and roll and the maximum pitch angle under 1-year return period waves at full load condition. To the author's knowledge, this study is the first attempt to combine altogether the hull and compartment modeling and full set of stability and hydrodynamic calculations precisely to optimize an FPSO's hull dimensions within 30 min. Also, it is worthwhile to mention that the developed methods are generic enough to be applied to all types of ship-shaped offshore platforms.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.835-840
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• 1989

We present new efficient interaction measures which can be used for control operability analysis and Control Structure selection in decentralized control systems. These measures can indicate not only the stability of decentralized control systems but also the true closed-loop Performance of the decentralized control structure. Relationships between published measures and proposed ones are clarified. Some important characteristics of these. measures are rigorously analyzed. The significance and the usefulness of the proposed method have been illustrated through examples found in the literature.

• Journal of Distribution Science
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• v.15 no.2
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• pp.27-36
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• 2017

Purpose - This study was intended to find the selection attribution factors and service satisfaction determinants of third party logistics suppliers in Dongdaemun wholesale market. Research design, data, and methodology - A questionnaire survey was performed, and the retailers and wholesalers in Dongdaemun wholesale market were asked to fill in it. Company employees using third party logistics service were selected by a random sampling method. Results - It is easy for both retailers and wholesalers to use third party logistics service. The logistics companies in Dongdaemun wholesale market have paid more heed to the security of freight and the operability. That is, the freight safety and operating service are the most important factors in selecting third party logistics suppliers, and they both have a close relationship with user satisfaction. There is no relation between service level and recognition in selection factors of third party logistics suppliers. All the responsiveness, operability and informativeness of third-party logistics providers has a significant relationship with user satisfaction. Conclusions - Third party logistics service is entirely different from the existing delivery or transport service. The most market vendors' wish for third party logistics suppliers is the stability of freight and robust operating service. They also demand the responsiveness for special or emergency situation with having information strength.

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.137-145
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• 2022

The usability evaluation of the remote fluid monitoring device, which was introduced to reduce the work of nurses and increase the efficiency, was performed due to the expansion of the non-face-to-face medical system. Remote fluid monitoring is a fusion of various technologies such as fluid measurement and analysis, error correction technology, and transmission technology. The range of use by users, the information they want to obtain, and the control device, etc. are wide, and the factors that evaluate the product are also diverse. Therefore, it is difficult to improve the product through evaluation. In this study, a quantitative index was developed to help improve the product for commercialization by conducting 20 usability evaluations in three areas of product stability, operability, and satisfaction with the remote sap monitoring system device. It was performed through infrared and load cell-type sap monitoring devices. In terms of stability, there was a difference in installation work such as fixing the pole of the device, and high satisfaction was shown for operability and accuracy. In terms of product satisfaction, the satisfaction of load cell devices was generally high.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.4
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• pp.155-162
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• 2023

PURPOSE: The primary objective of this study was to develop a virtual reality-based vestibular rehabilitation system to enhance balance perception, target rehabilitation specialists, and evaluate its usability. A key goal was establishing a system refinement strategy based on the collected data. METHODS: We conducted a study involving ten adults aged 10 to 29 in Gwangju Metropolitan City to evaluate the usability of a virtual reality-based vestibular rehabilitation system to enhance balance perception. After introducing the product and explaining its use to the participants, balance assessments and training were conducted using computerized dynamic posturography (CDP) (also called the test of balance [TOB]). Subsequently, participants were given a questionnaire to evaluate subjective stability, operability, and satisfaction. Frequency analysis was utilized to determine the frequency of the variable values of the measurement items in the survey for descriptive statistics. RESULTS: We found that the average usability score was 2.587. When broken down by category, stability received an average rating of 2.725, operability scored an average of 2.783, and satisfaction averaged 2.454. These findings suggest that most participants experienced positive sentiments and considerable satisfaction. CONCLUSION: The study successfully developed a virtual reality-based vestibular rehabilitation system, which was an improvement over the previous model and addressed its shortcomings. The results show that users with vestibular impairments are satisfied and more engaged with this system, indicating that additional studies are warranted.

• Journal of Hydrogen and New Energy
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• v.28 no.6
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• pp.712-720
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• 2017

As Korean government has activated the renewable portfolio standard (RPS) since 2012, producers have been seeking and using the various renewable resources to meet the RPS quota. One of these efforts, Power Bio-Fuel oil demonstration project is being conducted to check the operability and compatibility with fossil fuel, Fuel oil (B-C) from 2014. The oil is a mixture of vegetable oil and animal fat or fatty acid ester of them and should satisfy some specification to use the power generation. The oil's quality and combustion characteristics are different from conventional oil, Fuel oil (B-C) in current power plant facility. In this study, it was investigated the storage stability and malodor intensity of Bio-Fuel oil.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.3
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• pp.119-126
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• 2017

In the clinical setting, the pressure bio-feedback device is used for the spinal rehabilitation of patients with back pain, but it has several disadvantages. The purpose of this study was to develop a digitalized pressure biofeedback system that provides precise exercise method and posture in real time during the spinal rehabilitation exercise by sensing and monitoring body movements and balance of users and providing biofeedback to users. After that, the usability testing for a digitalized pressure biofeedback system will be conducted to identify problems such as safety, performance, operability, and satisfaction, and suggest improvement directions. A total of 33 subjects were participated in the usability testing. The experts group and the users group evaluated the developed digitalized pressure biofeedback system on a scale of 5 points after using the equipment. In the user group, safety was 3.59, operability was 4.38, satisfaction was 4.49. In the expert group, safety was 2.86, operability was 3.91, and performance was 4.28. Based on the usability evaluation, if the problems of stability of the cradle for tablet PC, air injection, screen display, etc. are solved, it becomes a exercise device capable of accurately exercising and evaluating the function of the spine by checking its own motion state while the spinal stabilization exercise.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.6
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• pp.639-643
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• 1997

This paper presents how nonlinear PID control algorithms can be applied on chemical processes for a more stable operation and perfect automation. A pass balance controller is designed to balance the exiting temperatures of a heater and a heat exchange network. The proposed controller has gain-varying integral action and deals with the operational constraints in an efficient manner. Also, the use of a PID gap controller is proposed to maximize energy saving and operation stability and to minimize operator intervention in operation of air fan coolers. The proposed controller adjusts the opening of a louver automatically in such a way that it keeps the air fan pitch position within the desired range. All these nonlinear PID controllers have been implemented on the distributed control system (DCS) for good reliability and operability. Operator acceptance was very high and the implemented controllers have shown good performance and high service factor still now on. The proposed methodology can be directly applied to similar processes without any modification.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.5
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• pp.2719-2722
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• 2016

Circulatory miR-133a is a marker shared by several types of cancer. In this study we evaluated the feasibility of using miR-133a levels in gastric juice to screen for gastric cancer. A total of 204 samples of gastric juice and mucosa from gastric cancer, atrophic gastritis, gastric ulcer, superficial gastritis and healthy cases were collected by gastroscopy. The results showed that miR-133a levels in gastric juice and carcinoma tissues of patients with gastric cancer were significantly downregulated and positively correlated. Moreover, miR-133a in gastric juice has high operability, high reliability, high sensitivity, high specificity and relative stability, fit for clinical diagnosis of gastric cancer.