• 제목/요약/키워드: stable limits

검색결과 151건 처리시간 0.026초

Effects of Aquatic and Ground Obstacle Training on Balance and Muscle Activity in Patients With Chronic Stroke

  • Hwang, Hyun-chul;Kim, So-hee;Kim, Tae-ho
    • 한국전문물리치료학회지
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    • 제26권4호
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    • pp.35-41
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    • 2019
  • Background: Obstacle training affects lower limb muscle activity, balance, reducing the risk of falls, and making gait more stable. Objects: This study aimed to investigate the effects of aquatic and ground obstacle training on balance and muscle activity in patients with chronic stroke. Methods: The study subjects included 30 patients with stroke, who were divided into aquatic ($n_1=15$) and ground ($n_2=15$) groups. Groups underwent obstacle training three times per week, 30 min per session, for six weeks that went as follows: walking over sites with the paralyzed leg, stepping onto and down from a box step, and walking over obstacles with the non-paralyzed leg. Results: The experimental results were obtained by comparing muscle activity. Activity of the rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius were significantly increased in the aquatic group (p<.05). Activity of the biceps femoris and tibialis anterior were significantly increased in the ground group (p<.05); however, the rectus femoris and gastrocnemius were not significantly different. In the comparison of maximal distance regarding the limits of stability, it was significantly increased on the non-affected side, affected side, and anterior and posterior distance in the aquatic group (p<.05). It was significantly increased in the non-affected side and anterior and posterior distance the ground group (p<.05); however, maximal distance on the affected side distance was not significantly different. Conclusion: Gait training with aquatic and ground obstacles is effective for improving balance and gait ability of patients with stroke. However, it was more effective for the aquatic group than for the ground group.

품질손실을 고려한 경제적 CUSUM 관리도 (A Design of Economic CUSUM Control Chart Incorporating Quality Loss Function)

  • 김정대
    • 산업경영시스템학회지
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    • 제41권4호
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    • pp.203-212
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    • 2018
  • Quality requirements of manufactured products or parts are given in the form of specification limits on the quality characteristics of individual units. If a product is to meet the customer's fitness for use criteria, it should be produced by a process which is stable or repeatable. In other words, it must be capable of operating with little variability around the target value or nominal value of the product's quality characteristic. In order to maintain and improve product quality, we need to apply statistical process control techniques such as histogram, check sheet, Pareto chart, cause and effect diagram, or control charts. Among those techniques, the most important one is control charting. The cumulative sum (CUSUM) control charts have been used in statistical process control (SPC) in industries for monitoring process shifts and supporting online measurement. The objective of this research is to apply Taguchi's quality loss function concept to cost based CUSUM control chart design. In this study, a modified quality loss function was developed to reflect quality loss situation where general quadratic loss curve is not appropriate. This research also provided a methodology for the design of CUSUM charts using Taguchi quality loss function concept based on the minimum cost per hour criterion. The new model differs from previous models in that the model assumes that quality loss is incurred even in the incontrol period. This model was compared with other cost based CUSUM models by Wu and Goel, According to numerical sensitivity analysis, the proposed model results in longer average run length in in-control period compared to the other two models.

부하 임피던스 변화에 따른 6.78MHz 전류모드 D급 전력증폭기 특성 해석 (Performance Analysis of 6.78MHz Current Mode Class D Power Amplifier According to Load Impedance Variation)

  • 고석현;박대길;구경헌
    • 한국항행학회논문지
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    • 제23권2호
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    • pp.166-171
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    • 2019
  • 본 논문은 6.78 MHz무선전력전송 송신기의 전송 효율을 높이고 송수신 코일 간격 변화에도 안정적 특성을 확보하기 위해 전류 모드 클래스 D 전력증폭기를 설계한다. 선형증폭기의 이론적인 효율을 제한하는 트랜지스터의 기생 커패시터 성분에 의한 손실을 적게 만들어 전력증폭기의 효율을 향상시킨다. 회로 설계 시뮬레이터를 이용하여 고효율 증폭기를 설계하고 부하 임피던스 변화에 따른 전력 출력, 효율 특성을 시뮬레이션하여 검증하였다. 시뮬레이션에서 DC 바이어스 30 V일 때 42.1 dBm의 출력과 95%의 효율을 갖도록 설계하였다. 전력증폭기를 제작하여 42.1 dBm (16 W)의 출력에서 91%의 효율을 보였다. 드론 무선전력전송에 적용될 송수신 코일을 제작하였으며, 송수신 코일 간격에 따른 부하변화에 따라 전력부가효율이 최대 88% 이고 출력전력 $42.1dBm{\pm}1.7dB$의 특성을 나타내었다.

Loosely Coupled Resonant DAB 컨버터의 안정적인 초기 구동을 위한 동작 주파수 설계 (Operating Frequency Design for Stable Initial Operation of Loosely Coupled Resonant DAB Converter)

  • 백승혁;김성민;이재홍;이승환
    • 전력전자학회논문지
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    • 제26권6호
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    • pp.437-445
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    • 2021
  • This paper proposes an operating frequency design method that limits the voltage applied to aload-side converter during the initial operation of a loosely coupled resonant dual-active bridge (LCR-DAB) converter and an initial operating strategy that applies it. The LCR-DAB converter uses two wireless power transfer coils instead of the high-frequency transformer of the general DAB converter. The wireless power coil has a physical distance of several tens of millimeter or more between the two coils; thus, the LCR-DAB converter is a bidirectional isolated power conversion system that can easily achieve high insulation performance. However, for the initial operation of the LCR-DAB, if the power-side converter is operated at the resonance frequency while the load-side converter is not operating, then a very high voltage due to resonance is applied to the load-side converter, thereby causing damage to the converter. Therefore, a method that can stably charge the DC link voltage of the secondary-side converter during the initial operation is needed. This paper proposes a method to initially charge the secondary-side DC link by operating the primary-side converter at a frequency with limited voltage gain rather than at a steady-state operating frequency. The validity of the proposed frequency design method and initial operating sequence is verified through simulation and experimentation of the 1 KW LCR-DAB converter.

Clinical and preclinical tolerance protocols for vascularized composite allograft transplantation

  • Yang, Jerry Huanda;Johnson, Ariel C.;Colakoglu, Salih;Huang, Christene A.;Mathes, David Woodbridge
    • Archives of Plastic Surgery
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    • 제48권6호
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    • pp.703-713
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    • 2021
  • The field of vascularized composite allografts (VCAs) has undergone significant advancement in recent decades, and VCAs are increasingly common and accepted in the clinical setting, bringing hope of functional recovery to patients with debilitating injuries. A major obstacle facing the widespread application of VCAs is the side effect profile associated with the current immunosuppressive regimen, which can cause a wide array of complications such as infection, malignancy, and even death. Significant concerns remain regarding whether the treatment outweighs the risk. The potential solution to this dilemma would be achieving VCA tolerance, which would allow recipients to receive allografts without significant immunosuppression and its sequelae. Promising tolerance protocols are being studied in kidney transplantation; four major trials have attempted to withdraw immunosuppressive treatment with various successes. The common theme in all four trials is the use of radiation treatment and donor cell transplantation. The knowledge gained from these trials can provide valuable insight into the development of a VCA tolerance protocol. Despite similarities, VCAs present additional barriers compared to kidney allografts regarding tolerance induction. VCA donors are likely to be deceased, which limits the time for significant pre-conditioning. VCA donors are also more likely to be human leukocyte antigen-mismatched, which means that tolerance must be induced across major immunological barriers. This review also explores adjunct therapies studied in large animal models that could be the missing element in establishing a safe and stable tolerance induction method.

팬톤 올해의 컬러와 메이크업 기법을 적용시킨 아트메이크업 작품연구 (A Study on Art Makeup Works that Applied Pantone Color of the Year and Makeup Techniques)

  • 이설하;김혜균
    • 패션비즈니스
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    • 제26권3호
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    • pp.19-32
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    • 2022
  • This study aimed to analyze the relationship between makeup and Pantone color by reflecting the visual elements of modern people who react sensitively to trends, and to research and propose art makeup using various techniques based on the results. The scope of this study was the last 5 years for researching trend colors. The range of colors was from 2016 to 2020, and the research method was designed after examining makeup trends using Pantone colors from 2016 to 2020; the characteristics of color and trend makeup were analyzed to design art makeup using various techniques. With respect to research data, literature review was conducted on the makeup design using Pantone colors with trend makeups. By referring to data in Pantone's official website, the characteristics and meanings of each color were analyzed. Based on research data, illustrations were made and makeup was designed and suggested. According to the study results, one-color makeup created a stable and uniform mood as a whole and could highlight the characteristics of each color. On the other hand, the makeup design that mixed Pantone colors harmonized the complementary colors and created an original and beautiful makeup design. The researcher identified the relationship and characteristics of trend colors and makeup and suggested various techniques, and expects that by linking the effect of trend color with makeup, designs and visual effects that go beyond the limits of the makeup market will be suggested and expanded.

DEVELOPMENT OF LIGHTWEIGHT OPTICAL TELESCOPE KIT USING ALUMINUM PROFILE AND ISOGRID STRUCTURE

  • Park, Woojin;Lee, Sunwoo;Han, Jimin;Ahn, Hojae;Ji, Tae-Geun;Kim, Changgon;Kim, Dohoon;Lee, Sumin;Kim, Young-Jae;Kim, Geon-Hee;Kim, Junghyun;Kim, Ilhoon;Pak, Soojong
    • 천문학회지
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    • 제55권1호
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    • pp.11-22
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    • 2022
  • We introduce the Transformable Reflective Telescope (TRT) kit that applies an aluminum profile as a base plate for precise, stable, and lightweight optical system. It has been utilized for optical surface measurements, developing alignment and baffle systems, observing celestial objects, and various educational purposes through Research & Education projects. We upgraded the TRT kit using the aluminum profile and truss and isogrid structures for a high-end optical test device that can be used for prototyping of precision telescopes or satellite optical systems. Thanks to the substantial aluminum profile and lightweight design, mechanical deformation by self-weight is reduced to maximum 67.5 ㎛, which is an acceptable misalignment error compared to its tolerance limits. From the analysis results of non-linear vibration simulations, we have verified that the kit survives in harsh vibration environments. The primary mirror and secondary mirror modules are precisely aligned within 50 ㎛ positioning error using the high accuracy surface finished aluminum profile and optomechanical parts. The cross laser module helps to align the secondary mirror to fine-tune the optical system. The TRT kit with the precision aluminum mirror guarantees high quality optical performance of 5.53 ㎛ Full Width at Half Maximum (FWHM) at the field center.

pH조절 분배추출에 의한 식물체 중 Methoxyfenozide와 Bentazone의 HPLC 분석 (Analysis of Methoxyfenozide and Bentazone in Plant with HPLC by pH-Adjusted Liquid-liquid Partition Cleanup)

  • 노석초;황철환;유기용;한성수
    • 한국환경농학회지
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    • 제26권3호
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    • pp.246-253
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    • 2007
  • 이 연구는 액액분배과정 중 pH 조절에 의한 diacylhyazine계의 곤충생장조정(IGR)계 살충제 methoxyfenozide와 benzothiadiazinone계의 제초제 bentazone의 분배효율을 향상시키기 위하여 수행하였다. 현미시료는 두 약제 모두 "추출$\rightarrow$응고법$\rightarrow$분배추출$\rightarrow$florisil column chromatography"의 동일한 과정을 거쳤다. 볏짚시료에 있어서 methoxyfenozide는 "추출$\rightarrow$1 M-NaOH 용액에 의한 알칼리화$\rightarrow$분배추출$\rightarrow$응고법$\rightarrow$florisil column chromatography"의 과정을 거친 후 용리액인 acetonitrile : 20 mM sodium acetate(75:25, v/v)로 정용, HPLC로 분석하였다. Bentazone의 경우는 "추출$\rightarrow$1 M-NaOH 용액 첨가에 의한 알칼리화$\rightarrow$유기용매 세척$\rightarrow$12 M-HCl 의한 산성화$\rightarrow$분배추출$\rightarrow$florisil column chromatography"의 과정을 거쳤으며, acetonitrile : 75 mM sodium acetate(pH 6.0) (40:60, v/v)로 정용, HPLC로 분석 하였다. Methoxyfenozide의 회수율은 현미 83.5-97.4%, 볏짚 86.4-97.3%였으며, 분석법의 검출한계는 현미 0.02 mg/kg 볏짚 0.04 mg/kg이었다. Bentazone의 회수율은 현미 86.8-101.9 %, 볏짚 88.3-94.5%였으며, 분석법의 검출한계는 현미 0.005 mg/kg, 볏짚 0.01 mg/kg이었다. 본 연구결과에서 얻은 위 방법은 재현성 있는 안정적 분석조건을 제공한다는 점에서 두 약제의 잔류분석에 유용하게 적용될 수 있을 것으로 생각된다.

다량조리 튀김식품 종류에 따른 대두유의 가열산화 (Effects of Thermooxidation of Soybean Oil in Association with Fried Foods on Quantity Food Production)

  • 최은수;길복임
    • 동아시아식생활학회지
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    • 제21권5호
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    • pp.723-730
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    • 2011
  • 본 연구는 튀김식품의 종류에 따른 대두유의 가열산화변화를 여러 이화학적 품질지표들을 측정함으로써 장시간 가열처리에 따른 대두유의 산화안정성을 살펴보았다. 튀김유로 대두유를 사용하여 $180^{\circ}C$에서 72시간 동안 프렌치프라이, 치킨너겟, 도넛을 튀겼다. 튀김유의 가열산화 변화를 알아보기 위해 유리지방산가, 과산화물가, 총극성화합물 함량, 공액이중산가를 측정하였고, 유전항수, 굴절률, 요오드가, 발연점, 지방산 조성 중 불포화지방산과 포화지방산의 비(U/S)를 분석하였다. 튀김 시간에 비례하여 유리지방산가, 총극성화합물 함량, 공액이중산가, 유전항수, 굴절률은 증가하고, 요오드가, 발연점, U/S 비는 감소하였다. 모든 튀김유 시료에서 법적 규제치인 산가는 2.0% 이하와 총극성화합물 함량 25% 이하를 나타냈다. 그러나 과산화물가는 튀김 시간과 무관하게 증가와 감소를 반복하였다. 치킨너겟 튀김유가 프렌치프라이나 도넛 튀김유에 비해 가열산화에 더 안정한 것으로 나타나, 튀김식품의 종류가 튀김유 변질 속도에 영향을 주는 것을 알 수 있었다. 튀김유의 품질을 나타내는 여러 이화학적 지표 중 굴절률이나 유전항수는 간편법으로 산업 현장에서 유용하게 이용될 수 있을 것이다.

중소기업간 금융결제를 지원하는 e-MP 서비스 활성화 방안 (e-MP service activation research to support SME financial settlement)

  • 유순덕;남기정
    • 디지털융복합연구
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    • 제11권12호
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    • pp.61-67
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    • 2013
  • B2C의 "신용카드"를 대체할 만한 "결제수단"으로 2001년 신용보증기금과 은행, (물류업체), e-MP(Market Place)가 참여하여, 기업간 e-MP(기업간 전자결제 결제 시스템)를 통한 전자상거래에 의한 구매를 신용보증기금이 보증해 주는 B2B 전자상거래보증제도를 도입하였다. 기업간 전자상거래를 지원하는 전자결제시스템인 e-MP 서비스는 지난 10년 동안 운영되어 중소기업의 성장에 많은 기여를 하였다. 기업 간 전자상거래보증은 구매기업에게 거래한도 확장으로 안정적인 구매처를 확보하고 업무 프로세스 개선을 통한 기업 경쟁력 강화에 기여하였다. 그러나, 신용보증기관의 보증지원을 기반으로 한 사업으로서 규모의 한계를 보유하고 있다. 신용보증기관의 보증지원을 기반으로 한 사업으로서 규모의 한계를 극복하기 위해서는 정부의 중소기업에 대한 직접 또는 간접지원의 강화 운영을 e-MP 사업기반으로 해야 한다. 또한 e-MP서비스를 통한 새로운 모델 개척이 필요하다. 기업간 전자상거래 활성화 측면 뿐만 아니라 e-MP의 새로운 수익모델을 위해 신용보증기관이 직접 개입하여 운영하는 기업간 통합온라인장터 구축과 이를 활용하는 기업에게 구매자금을 동시에 제공하는 모델에 대한 검토가 필요하다.