• 제목/요약/키워드: Virginia Tech

검색결과 138건 처리시간 0.021초

Fall Risk Assessments Based on Postural and Dynamic Stability Using Inertial Measurement Unit

  • Liu, Jian;Zhang, Xiaoyue;Lockhart, Thurmon E.
    • Safety and Health at Work
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    • 제3권3호
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    • pp.192-198
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    • 2012
  • Objectives: Slip and fall accidents in the workplace are one of the top causes of work related fatalities and injuries. Previous studies have indicated that fall risk was related to postural and dynamic stability. However, the usage of this theoretical relationship was limited by laboratory based measuring instruments. The current study proposed a new method for stability assessment by use of inertial measurement units (IMUs). Methods: Accelerations at different body parts were recorded by the IMUs. Postural and local dynamic stability was assessed from these measures and compared with that computed from the traditional method. Results: The results demonstrated: 1) significant differences between fall prone and healthy groups in IMU assessed dynamic stability; and 2) better power of discrimination with multi stability index assessed by IMUs. Conclusion: The findings can be utilized in the design of a portable screening or monitoring tool for fall risk assessment in various industrial settings.

미국의 디지털 도서관 구축현황 (Current Status of Digital Library Programs in USA)

  • 최호남
    • 정보관리연구
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    • 제26권3호
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    • pp.32-53
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    • 1995
  • 디지털 도서관은 정보하부구조에 있어서 가장 으뜸가는 요소로 부각되고 있다. 일반적으로 미국대학도서관의 디지털 도서관 추진형태는 정보기술 하부구조 구축, 본문 데이터베이스 구축, 프로젝트 중심의 설계로 집약된다. 본 고에서는 미국의 미시건대학교, 카네기멜론대학교, 버지니아공과대학교 도서관을 중심으로 디지털도서관 구축실태와 현황을 고찰하였다.

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항공기 엔진용 유체 마운트의 성능해석

  • 안영공
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 1998년도 강연회 및 연구개발 발표회 논문집
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    • pp.220-227
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    • 1998
  • This paper evaluate the performance of a Magneto-Rheological (MR) fluid mount. The mount incorporates MR fluid in a conventional fluid mount to open and closed the inertia track between the fluid chambers of the mount. It is shown that such switching of the inertia track improves the mount's isolation effect, by eliminating the large transmissibility peak that commonly exists at frequencies higher than the notch frequency for conventional fluid mounts. The switching frequencies of the MR mount is evaluated, based on the parameters of the mount. A simple control scheme for switching the mount between the open and closed states is proposed, and the performance of the controlled mount is compared with conventional mounts. A sensitivity analysis is conducted to evaluate the effect of parameter errors in estimating the switching frequencies and mount performance. The results show that the switching frequencies can be accurately determined from mount parameters that are easily measured or estimated.

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직물의 소리가 주관적 감각에 미치는 영향 (Effect of Fabric Sound on Subjective Sensation)

  • 조길수
    • 한국감성과학회:학술대회논문집
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    • 한국감성과학회 1999년도 춘계학술발표논문집 논문집
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    • pp.265-269
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    • 1999
  • This study was carried out to evaluate human subjective sensation for fabric rustling sounds and predict the sensation with quantified sound color measurements and mechanical properties of fabrics. Thirty subjects at Virginia Tech were asked to evaluate seven sound sensation descriptors by semantic differential scale after hearing eight different fabric sounds. Sound measurements were quantified by calculating total sound pressure(LPT), level range(ΔL), and frequency difference (Δf). Mechanical properties of fabrics were measured by KES-FB. Subjective sensation for fabric sound showed significant differences among fabrics except clearness sensation. Subjective sensation predicted by sound measurements showed well fitted regression equation with ΔL and LPT> Sharpness, clearness, and highness were significantly released with mechanical properties of fabrics. All sensation was found to be predicted with sound measurements L:PT and Δf and mechanical properties such as LT, 2HG5, WC, T, and W.

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Impact of nonphysician, technology-guided alert level selection on rates of appropriate trauma triage in the United States: a before and after study

  • Megan E. Harrigan;Pamela A. Boremski;Bryan R. Collier;Allison N. Tegge;Jacob R. Gillen
    • Journal of Trauma and Injury
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    • 제36권3호
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    • pp.231-241
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    • 2023
  • Purpose: Overtriage and undertriage rates are critical metrics in trauma, influenced by both trauma team activation (TTA) criteria and compliance with these criteria. Analysis of undertriaged patients at a level I trauma center revealed suboptimal compliance with existing criteria. This study assessed triage patterns after implementing compliance-focused process interventions. Methods: A physician-driven, free-text alert system was modified to a nonphysician, hospital dispatcher-guided system. The latter employed dropdown menus to maximize compliance with criteria. The preintervention period included patients who presented between May 12, 2020, and December 31, 2020. The postintervention period incorporated patients who presented from May 12, 2021, through December 31, 2021. We evaluated appropriate triage, overtriage, and undertriage using the Standardized Trauma Assessment Tool. Statistical analyses were conducted with an α level of 0.05. Results: The new system was associated with improved compliance with existing TTA criteria (from 70.3% to 79.3%, P=0.023) and decreased undertriage (from 6.0% to 3.2%, P=0.002) at the expense of increasing overtriage (from 46.6% to 57.4%, P<0.001), ultimately decreasing the appropriate triage rate (from 78.4% to 74.6%, P=0.007). Conclusions: This study assessed a workflow change designed to improve compliance with TTA criteria. Improved compliance decreased undertriage to below the target threshold of 5%, albeit at the expense of increased overtriage. The decrease in appropriate triage despite compliance improvements suggests that the current criteria at this institution are not adequately tailored to optimally balance the minimization of undertriage and overtriage. This finding underscores the importance of improved compliance in evaluating the efficacy of TTA criteria.

건축물에서의 친환경개념에 대한 건축공학전공 대학생의 태도 (The Attitude of Construction Students toward Sustainability in the Built Environment)

  • 안용한;권혁수
    • 공학교육연구
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    • 제11권3호
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    • pp.70-77
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    • 2008
  • 이 연구는 친환경 개념에 대한 건축공학 대학생의 친숙함과 흥미의 정도, 태도, 그리고 친환경 개념에 대한 학생들의 태도를 향상시키기 위한 요인들을 조사하고 있다. 연구의 목적을 이루기 위해, 이 연구는 저자들에 의해 개발된 설문 조사 방법을 채택하고 있다. 이는 미국 버지니아주 버지니아 공대의 건축공학과 학생들을 대상으로 하는 설문조사를 기반으로 한 기술/상관 연구이다. SPSS를 이용한 기술통계와 다중회귀분석을 통하여 다음과 같은 결과를 제시하고 있다. 첫째, 건축공학 전공 학생들은 대체로 친환경 건축에 대한 높은 친밀감과 흥미를 가지고 있다. 둘째, 친환경 개념에 대한 건축공학 전공 학생들의 태도는 친환경 건축 수업, 친환경 관련 수업과 연구를 담당하는 교수진, 친환경적인 학생들의 학습환경 또는 시설들, 그리고 친환경 건설 관련 학교 행사와 실천과 같은 요인들에 기반해 달라지는 것으로 나타났다. 마지막으로, 친환경 개념에 대한 건축공학 학생들의 태도는 특히, 건축공학 프로그램에서 친환경 건축관련 수업을 제공함으로 향상될 수 있다.

Verification of a novel fuel burnup algorithm in the RAPID code system based on Serpent-2 simulation of the TRIGA Mark II research reactor

  • Anze Pungercic;Valerio Mascolino ;Alireza Haghighat;Luka Snoj
    • Nuclear Engineering and Technology
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    • 제55권10호
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    • pp.3732-3753
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    • 2023
  • The Real-time Analysis for Particle-transport and In-situ Detection (RAPID) Code System, developed based on the Multi-stage Response-function Transport (MRT) methodology, enables real-time simulation of nuclear systems such as reactor cores, spent nuclear fuel pools and casks, and sub-critical facilities. This paper presents the application of a novel fission matrix-based burnup methodology to the well-characterized JSI TRIGA Mark II research reactor. This methodology allows for calculation of nuclear fuel depletion by combination and interpolation of RAPID's burnup dependent fission matrix (FM) coefficients to take into account core changes due to burnup. The methodology is compared to experimentally validated Serpent-2 Monte Carlo depletion calculations. The results show that the burnup methodology for RAPID (bRAPID) implemented into RAPID is capable of accurately calculating the keff burnup changes of the reactor core as the average discrepancies throughout the whole burnup interval are 37 pcm. Furthermore, capability of accurately describing 3D fission source distribution changes with burnup is demonstrated by having less than 1% relative discrepancies compared to Serpent-2. Good agreement is observed for axially and pin-wise dependent fuel burnup and nuclear fuel nuclide composition as a function of burnup. It is demonstrated that bRAPID accurately describes burnup in areas with high gradients of neutron flux (e.g. vicinity of control rods). Observed discrepancies for some isotopes are explained by analyzing the neutron spectrum. This paper presents a powerful depletion calculation tool that is capable of characterization of spent nuclear fuel on the fly while the reactor is in operation.

Performance of Protection Systems during Catastrophic failures in Power Systems

  • Phadke Arun G.
    • KIEE International Transactions on Power Engineering
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    • 제5A권2호
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    • pp.103-108
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    • 2005
  • Catastrophic failures in power systems are rare but not uncommon events. Protection systems play an important role in the progression of events during a catastrophic failure. This paper will examine some of the historical records, and suggest possible improvements to protection systems which can have a positive impact on power system performance during catastrophic failures.