• 제목/요약/키워드: stability and operability

검색결과 21건 처리시간 0.037초

Consideration of Human Operators in Man-Machine Systems

  • Jin, Jae-Hyun;Ahn, Sung-Ho;Park, Byung-Suk;Yoon, Ji-Sup;Jung, Jae-Hoo
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2003년도 ICCAS
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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.

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Parametric optimization of FPSO hull dimensions for Brazil field using sophisticated stability and hydrodynamic calculations

  • Lee, Jonghun;Kim, Byung Chul;Ruy, Won-Sun;Han, Ik Seung
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제13권1호
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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.

New interaction measures for decentralized control systems

  • Lee, Moonyong;Park, Sunwon
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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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.

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A Study on the Determinants of Third Party Logistics Service Suppliers in Dongdaemun Market

  • Zhang, Yu-Liang;Yoo, Chang-Gwon;Kim, Gi-Pyoung
    • 유통과학연구
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    • 제15권2호
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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.

비대면 환자 간호시스템 적용을 위한 융합기술의 원격 수액모니터링 장치 사용성평가 지표 개발 및 결과 분석 (Development of usability evaluation index of convergence technology remote fluid monitoring device for non-face-to-face patient nursing system application and analysis of results)

  • 김선칠
    • 한국융합학회논문지
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    • 제13권4호
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    • pp.137-145
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    • 2022
  • 비대면 의료시스템의 확대로 간호사의 업무 경감 및 효율성을 높이기 위해서 도입되는 원격수액모니터링 장치의 사용성평가를 수행하였다. 원격 수액 모니터링은 수액 측정시술과 분석, 오차 교정기술, 전송기술 등 다양한 기술이 융복합되어 있다. 사용자가 사용하는 범위와 얻고자 하는 정보, 조절 장치 등 사용범위가 넓으며 제품을 평가하는 요소도 다양하다. 따라서 평가를 통해 제품을 개선하는데 어려움이 있다. 본 연구에서는 원격수액모니터링 시스템장치를 제품의 안정성, 조작성, 만족도의 3개 영역에서 20개의 사용성평가를 실시하여 상용화를 위한 제품개선에 도움을 주고자 정량적인 지표를 개발하였다. 적외선 방식과 로드셀 방식의 수액모니터링 장치를 통해 수행하였으며, 안정성에서는 장치의 폴대고정 등 설치작업에 대해 차이가 있었으며, 조작성과 정확성에 대해서는 높은 만족도를 나타내었다. 제품의 만족도에서는 로드셀 장치의 만족도가 대체로 높게 나타났다.

균형감각 증진용 가상현실 기반 전정재활 시스템 개발 및 사용성 평가 (Development and Usability Evaluation of A Virtual Reality-Based Vestibular Rehabilitation System for Balance Enhancement)

  • 박근홍;이현민
    • 대한물리의학회지
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    • 제18권4호
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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.

바이오중유의 저장안정성 및 악취특성 연구 (A Study on the Storage Stability and Malodor of Bio-Fuel oil)

  • 장은정;박천규;이봉희
    • 한국수소및신에너지학회논문집
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    • 제28권6호
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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.

척추재활운동을 위한 디지털 압력바이오피드백 장치의 사용성 평가 (Usability Testing of Digital Pressure Bio-feedback for Spinal Rehabilitation Exercise)

  • 김태호;오도봉;김다연
    • 재활복지공학회논문지
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    • 제11권3호
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    • pp.119-126
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    • 2017
  • 임상현장에서 압력 바이오피드백 장치는 요통 환자들의 척추재활운동에 사용되고 있으나, 여러 가지 단점을 갖고 있다. 본 연구는 사용자에게 신체의 움직임과 균형을 센싱하고 모니터링하여 사용자에게 바이오피드백을 제공함으로써 척추재활운동시 실시간으로 정확한 운동방법과 자세를 제공하는 디지털화된 압력 바이오피드백 장치를 개발하고자 하였다. 그 후 사용성 평가를 진행하여 안전성, 수행성, 조작성, 만족성 등의 문제점을 파악하고 개선방향을 제시하고자 한다. 본 연구에 참여한 대상자는 총 33명으로 전문가 평가 집단 11명, 사용자 평가 집단 22명으로 실제 개발된 장비를 사용 후 5점 척도로 평가하였다. 사용자 집단에서는 안전성 3.59점, 조작성 4.38점, 만족성 4.49점으로 나타났으며, 전문가 집단에서는 안전성 2.86점, 조작성 3.91점, 수행성 4.28점으로 나타났다. 본 사용성 평가를 바탕으로 태블릿PC 거치대의 안정성 문제, 공기주입, 화면 표시 등의 문제점을 개선한다면 척추안정화 운동을 하면서 실시간 자신의 운동상태를 확인하여 정확한 운동과 기능 평가가 가능한 운동장치가 될 것이다.

비선형 PID 제어기의 최적 설계및 실제 적용 (Optimal design and real application of nonlinear PID controllers)

  • 이문용;구도균;이종민
    • 제어로봇시스템학회논문지
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    • 제3권6호
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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.

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Downregulated MicroRNA-133a in Gastric Juice as a Clinicopathological Biomarker for Gastric Cancer Screening

  • Shao, Juan;Fang, Peng-Hua;He, Biao;Guo, Li-Li;Shi, Ming-Yi;Zhu, Yan;Bo, Ping;Zhang, Zhen-Wen
    • Asian Pacific Journal of Cancer Prevention
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    • 제17권5호
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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.