• 제목/요약/키워드: dynamic science assessment

검색결과 191건 처리시간 0.024초

Fall experience and dual-task during gait performance for community-dwelling persons with stroke

  • Kim, Min-Kyu;Kim, Eunjeong;Hwang, Sujin;Son, Dongwook
    • Physical Therapy Rehabilitation Science
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    • 제7권3호
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    • pp.109-113
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    • 2018
  • Objective: The purpose of this study was to investigate the effects of fall experience and task complexity on gait performance in community-dwelling persons with chronic hemiparetic stroke. Design: Cross-sectional study. Methods: Thirty-three persons who had a history of stroke participated in this study. The participants included 18 persons (aged mean 54.0, mean score of 24.6 points on the Montreal Cognitive Assessment, MoCA) with fall experience (faller group) and 15 persons (aged mean 53.7, mean score of 24.7 points on the MoCA) without fall experience (non-faller group) in the previous six months. This study measured balance and gait performance at two different conditions (with/without 70% of water filled in a 200 cc cup). The participants were clinically assessed using the 10-meter walk test (10MWT), 6-minute walk test (6MWT), Berg Balance scale (BBS), Dynamic Gait Index (DGI), and Timed Up-and-Go (TUG) test. Results: After analyzation, persons in the faller group performed significantly better on the 10MWT, 6MWT, BBS, DGI, and the TUG test in the no-cup-carrying condition than those in the cup-carrying condition (p<0.05). The persons in the non-faller group also performed significantly better in all outcome measures with the no-cup-carrying condition than those in the cup-carrying condition (p<0.05). However, there was no interaction between fall experience and task complexity in the two groups. Conclusions: Our results showed that balance and gait performance depended on fall experience and task complexity but fall experience did not interact with task complexity. Clinicians should consider fall prevention and task complexity during therapeutic approaches in persons with hemiparetic stroke.

Collaborative Governance in Philippine Science and Technology Parks: A closer look at the UP - Ayala Land Technohub

  • Sale, Jonathan P.
    • World Technopolis Review
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    • 제4권1호
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    • pp.23-32
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    • 2015
  • Public-private partnerships (PPPs) are very popular governance practices, as they enable the private partner to engage in business and have profits while the public partner improves the provision of public services. PPPs are organizational arrangements with a sector-crossing or sector-blurring nature, and are modes of governance - governance by partnerships or collaborative governance (Schuppert 2011). New models and applications of PPPs have been developed over time. Collaborative governance entails information exchange, action or movement harmonization, resource sharing, and capacity enhancement among the partners (Sale 2011; 2012a). As the national university, the University of the Philippines (UP) serves as a research university in various fields of expertise and specialization by conducting basic and applied research and development, and promoting research in various colleges and universities, and contributing to the dissemination and application of knowledge, among other purposes. (Republic Act 9500) It is the site of two (2) science and technology parks (Sale 2012b), one of which is the UP - Ayala Land Technohub. A collaboration between industry and the academe, the Technohub is envisioned as an integrated community of science and technology companies building a dynamic learning and entrepreneurial laboratory (UP-AyalaLand Technohub). This paper takes a closer look at the UP - Ayala Land Technohub as an example of a PPP or collaborative governance in science and technology parks. Have information exchange, action or movement harmonization, resource sharing, and capacity enhancement taken place in the Technohub? What are some significant outcomes of, and issues arising from, the PPP? What assessment indicators may be used? Is a governance instrument needed?

Global STI Capacity Index: Comparison and Achievement Gap Analysis of National STI Capacities

  • Bashir, Tariq
    • STI Policy Review
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    • 제6권2호
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    • pp.105-145
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    • 2015
  • Science, technology and innovation (STI) is crucially important to eradicating poverty, and making advances in various areas such as agriculture, health, environment, transport, industry, and telecommunications. Therefore, it is vital to the overall socioeconomic development of nations. The indispensable role of STI in the competitive globalized economy led to several attempts to measure national STI capacities. The present study outlines STI capacity around three sets of capabilities: technological capabilities, social capabilities, and common capabilities. The Global Science, Technology and Innovation Capacity (GSTIC) index was developed to provide current evidence on the national STI capacities of the countries, and to improve the composite indicators used for such purposes. The GSTIC ranks a large number of countries (167) on the basis of their STI capacities and categories them into four groups: i.e. leaders, dynamic adopters, slow adopters, and laggards. For more meaningful assessment of the STI capacities of nations, it captures the achievement gaps of individual countries with the highest achiever. The study also provides ranking and achievement gaps of nations in the nine GSTIC pillars: technology creation, R&D capacity, R&D performance, technology absorption, diffusion of old technologies, diffusion of recent innovations, exposure to foreign technology, human capital, and enabling factors. A more detailed analysis of the strengths and weaknesses in different pillars of STI capacity of ten selected countries is also provided. The results show that there are significant disparities among nations in STI capacity and its various aspects, and developing countries have much to catch-up with the developed nations. However, different countries may adopt different strategies according to their strengths and weaknesses. Useful insight into the strengths and weaknesses of the national STI capacities of different countries are provided in the study.

Analytical solution for natural frequency of monopile supported wind turbine towers

  • Rong, Xue-Ning;Xu, Ri-Qing;Wang, Heng-Yu;Feng, Su-Yang
    • Wind and Structures
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    • 제25권5호
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    • pp.459-474
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    • 2017
  • In this study an analytical expression is derived for the natural frequency of the wind turbine towers supported on flexible foundation. The derivation is based on a Euler-Bernoulli beam model where the foundation is represented by a stiffness matrix. Previously the natural frequency of such a model is obtained from numerical or empirical method. The new expression is based on pure physical parameters and thus can be used for a quick assessment of the natural frequencies of both the real turbines and the small-scale models. Furthermore, a relationship between the diagonal and non-diagonal element in the stiffness matrix is introduced, so that the foundation stiffness can be obtained from either the p-y analysis or the loading test. The results of the proposed expression are compared with the measured frequencies of six real or model turbines reported in the literature. The comparison shows that the proposed analytical expression predicts the natural frequency with reasonable accuracy. For two of the model turbines, some errors were observed which might be attributed to the difference between the dynamic and static modulus of saturated soils. The proposed analytical solution is quite simple to use, and it is shown to be more reasonable than the analytical and the empirical formulas available in the literature.

Seismic reliability evaluation of steel-timber hybrid shear wall systems

  • Li, Zheng;He, Minjuan;Lam, Frank;Zhou, Ruirui;Li, Minghao
    • Earthquakes and Structures
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    • 제13권3호
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    • pp.289-297
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    • 2017
  • This paper presents seismic performance and reliability evaluation on steel-timber hybrid shear wall systems composed of steel moment resisting frames and infill light frame wood shear walls. Based on experimental observations, damage assessment was conducted to determine the appropriate damage-related performance objectives for the hybrid shear wall systems. Incremental time-history dynamic analyses were conducted to establish a database of seismic responses for the hybrid systems with various structural configurations. The associated reliability indices and failure probabilities were calculated by two reliability methods (i.e., fragility analysis and response surface method). Both methods yielded similar estimations of failure probabilities. This study indicated the greatly improved seismic performance of the steel-timber hybrid shear wall systems with stronger infill wood shear walls. From a probabilistic perspective, the presented results give some insights on quantifying the seismic performance of the hybrid system under different seismic hazard levels. The reliability-based approaches also serve as efficient tools to assess the performance-based seismic design methodology and calibration of relative code provisions for the proposed steel-timber hybrid shear wall systems.

Bayesian demand model based seismic vulnerability assessment of a concrete girder bridge

  • Bayat, M.;Kia, M.;Soltangharaei, V.;Ahmadi, H.R.;Ziehl, P.
    • Advances in concrete construction
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    • 제9권4호
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    • pp.337-343
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    • 2020
  • In the present study, by employing fragility analysis, the seismic vulnerability of a concrete girder bridge, one of the most common existing structural bridge systems, has been performed. To this end, drift demand model as a fundamental ingredient of any probabilistic decision-making analyses is initially developed in terms of the two most common intensity measures, i.e., PGA and Sa (T1). Developing a probabilistic demand model requires a reliable database that is established in this paper by performing incremental dynamic analysis (IDA) under a set of 20 ground motion records. Next, by employing Bayesian statistical inference drift demand models are developed based on pre-collapse data obtained from IDA. Then, the accuracy and reasonability of the developed models are investigated by plotting diagnosis graphs. This graphical analysis demonstrates probabilistic demand model developed in terms of PGA is more reliable. Afterward, fragility curves according to PGA based-demand model are developed.

웹 페이지의 감성에 관한 연구 (A Study on sensibility of Web page)

  • 선지현;조경자;한광희
    • 감성과학
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    • 제6권4호
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    • pp.33-40
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    • 2003
  • 본 연구는 웹 페이지 디자인의 감성모형을 구축하기 위해 실시되었다. 감성요소를 추출하기 위하여 첫째, 감성을 표현하는 어휘를 수집하고, 둘째, 감성어휘를 의미미분법을 사용해서 분류하고 셋째, 요인분석과 다차원척도법의 통계분석을 사용하였다. 본 연구결과로 얻어진 18개의 대표 어휘는 '독특하다. 신선하다, 화려하다. 소프트하다. 차갑다, 따뜻하다. 생생하다, 간단하다, 간결하다, 이색적이다, 도회적이다, 환하다, 칙칙하다, 밝다, 어둡다. 동적이다, 남성적이다, 딱딱하다'였으며, 세 개의 '밝다-어둡다', '소프트하다-딱딱하다', '간단하다-화려하다'의 감성 공간을 얻을 수 있었다.

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식생 물 부족 지수의 추계학적 거동과 기후변화가 그에 미치는 영향 (Stochastic Behavior of Plant Water Stress Index and the Impact of Climate Change)

  • 한수희;유가영;김상단
    • 한국물환경학회지
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    • 제25권4호
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    • pp.507-514
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    • 2009
  • In this study, a dynamic modeling scheme is presented to describe the probabilistic structure of soil water and plant water stress index under stochastic precipitation conditions. The proposed model has the form of the Fokker-Planck equation, and its applicability as a model for the probabilistic evolution of the soil water and plant water stress index is investigated under a climate change scenario. The simulation results of soil water confirm that the proposed soil water model can properly reproduce the observations and show that the soil water behaves with consistent cycle based on the precipitation pattern. The simulation results of plant water stress index show two different PDF patterns according to the precipitation. The simple impact assessment of climate change to soil water and plant water stress is discussed with Korean Meteorological Administration regional climate model.

Probabilistic seismic performance evaluation of non-seismic RC frame buildings

  • Maniyar, M.M.;Khare, R.K.;Dhakal, R.P.
    • Structural Engineering and Mechanics
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    • 제33권6호
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    • pp.725-745
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    • 2009
  • In this paper, probabilistic seismic performance assessment of a typical non-seismic RC frame building representative of a large inventory of existing buildings in developing countries is conducted. Nonlinear time-history analyses of the sample building are performed with 20 large-magnitude medium distance ground motions scaled to different levels of intensity represented by peak ground acceleration and 5% damped elastic spectral acceleration at the first mode period of the building. The hysteretic model used in the analyses accommodates stiffness degradation, ductility-based strength decay, hysteretic energy-based strength decay and pinching due to gap opening and closing. The maximum inter story drift ratios obtained from the time-history analyses are plotted against the ground motion intensities. A method is defined for obtaining the yielding and collapse capacity of the analyzed structure using these curves. The fragility curves for yielding and collapse damage levels are developed by statistically interpreting the results of the time-history analyses. Hazard-survival curves are generated by changing the horizontal axis of the fragility curves from ground motion intensities to their annual probability of exceedance using the log-log linear ground motion hazard model. The results express at a glance the probabilities of yielding and collapse against various levels of ground motion intensities.

Modal parameters based structural damage detection using artificial neural networks - a review

  • Hakim, S.J.S.;Razak, H. Abdul
    • Smart Structures and Systems
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    • 제14권2호
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    • pp.159-189
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    • 2014
  • One of the most important requirements in the evaluation of existing structural systems and ensuring a safe performance during their service life is damage assessment. Damage can be defined as a weakening of the structure that adversely affects its current or future performance which may cause undesirable displacements, stresses or vibrations to the structure. The mass and stiffness of a structure will change due to the damage, which in turn changes the measured dynamic response of the system. Damage detection can increase safety, reduce maintenance costs and increase serviceability of the structures. Artificial Neural Networks (ANNs) are simplified models of the human brain and evolved as one of the most useful mathematical concepts used in almost all branches of science and engineering. ANNs have been applied increasingly due to its powerful computational and excellent pattern recognition ability for detecting damage in structural engineering. This paper presents and reviews the technical literature for past two decades on structural damage detection using ANNs with modal parameters such as natural frequencies and mode shapes as inputs.