2,251 research outputs found

    Sound radiation characteristics of a box-type structure

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    The finite element and boundary element methods are employed in this study to investigate the sound radiation characteristics of a box-type structure. It has been shown [T.R. Lin, J. Pan, Vibration characteristics of a box-type structure, Journal of Vibration and Acoustics, Transactions of ASME 131 (2009) 031004-1–031004-9] that modes of natural vibration of a box-type structure can be classified into six groups according to the symmetry properties of the three panel pairs forming the box. In this paper, we demonstrate that such properties also reveal information about sound radiation effectiveness of each group of modes. The changes of radiation efficiencies and directivity patterns with the wavenumber ratio (the ratio between the acoustic and the plate bending wavenumbers) are examined for typical modes from each group. Similar characteristics of modal radiation efficiencies between a box structure and a corresponding simply supported panel are observed. The change of sound radiation patterns as a function of the wavenumber ratio is also illustrated. It is found that the sound radiation directivity of each box mode can be correlated to that of elementary sound sources (monopole, dipole, etc.) at frequencies well below the critical frequency of the plates of the box. The sound radiation pattern on the box surface also closely related to the vibration amplitude distribution of the box structure at frequencies above the critical frequency. In the medium frequency range, the radiated sound field is dominated by the edge vibration pattern of the box. The radiation efficiency of all box modes reaches a peak at frequencies above the critical frequency, and gradually approaches unity at higher frequencies

    GROWTH THEORY AND ACCOUNTING FOR GROWTH OF THE TAIWANESE ECONOMY

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    A growth accounting and an econometric exercise are used to provide insights into the evolution of the Taiwanese economy over the period 1966-96. The approach links the GDP function of a multiple sector neoclassical growth model to growth accounting and, subsequently to the estimation of the parameters of this function. The growth accounting results show that the contribution of total factor productivity (TFP) to growth in GDP averaged about 32 percent over the period, and this contribution increased as the economy approached its long-run equilibrium during the decade of the 1980s, with evidence of some departure during 1991-96. Growth in TFP increased output growth in industry and services while growth in skilled labor benefited all sectors. Growth in capital stock increased the growth of the industrial sector the most, followed by services, but the effect on agricultural output growth was negative. Growth in TFP and capital stock appear to have increased the capacity of the industrial and service sectors to pull resources from agriculture.economic growth, productivity, technological change, International Development, Productivity Analysis, O3, O4, O5,

    The leafage of a chordal graph

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    The leafage l(G) of a chordal graph G is the minimum number of leaves of a tree in which G has an intersection representation by subtrees. We obtain upper and lower bounds on l(G) and compute it on special classes. The maximum of l(G) on n-vertex graphs is n - lg n - (1/2) lg lg n + O(1). The proper leafage l*(G) is the minimum number of leaves when no subtree may contain another; we obtain upper and lower bounds on l*(G). Leafage equals proper leafage on claw-free chordal graphs. We use asteroidal sets and structural properties of chordal graphs.Comment: 19 pages, 3 figure

    A Case Report of Hemophagocytic Lymphohistiocytosis Secondary to Disseminated Tuberculosis

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    A 72-year-old woman with past medical history of hypertention and type 2 diabsetes presented to the emergency department for one day history of fevers, poor oral intake, and fatigue

    Developing effective service policies for multiclass queues with abandonment:asymptotic optimality and approximate policy improvement

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    We study a single server queuing model with multiple classes and impatient customers. The goal is to determine a service policy to maximize the long-run reward rate earned from serving customers net of holding costs and penalties respectively due to customers waiting for and leaving before receiving service. We first show that it is without loss of generality to study a pure-reward model. Since standard methods can usually only compute the optimal policy for problems with up to three customer classes, our focus is to develop a suite of heuristic approaches, with a preference for operationally simple policies with good reward characteristics. One such heuristic is the Rμθ rule—a priority policy that ranks all customer classes based on the product of reward R, service rate μ, and abandonment rate θ. We show that the Rμθ rule is asymptotically optimal as customer abandonment rates approach zero and often performs well in cases where the simpler Rμ rule performs poorly. The paper also develops an approximate policy improvement method that uses simulation and interpolation to estimate the bias function for use in a dynamic programming recursion. For systems with two or three customer classes, our numerical study indicates that the best of our simple priority policies is near optimal in most cases; when it is not, the approximate policy improvement method invariably tightens up the gap substantially. For systems with five customer classes, our heuristics typically achieve within 4% of an upper bound for the optimal value, which is computed via a linear program that relies on a relaxation of the original system. The computational requirement of the approximate policy improvement method grows rapidly when the number of customer classes or the traffic intensity increases

    Randomized controlled trial of a home-based action observation intervention to improve walking in Parkinson disease

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    Published in final edited form as: Arch Phys Med Rehabil. 2016 May ; 97(5): 665–673. doi:10.1016/j.apmr.2015.12.029.OBJECTIVE: To examine the feasibility and efficacy of a home-based gait observation intervention for improving walking in Parkinson disease (PD). DESIGN: Participants were randomly assigned to an intervention or control condition. A baseline walking assessment, a training period at home, and a posttraining assessment were conducted. SETTING: The laboratory and participants' home and community environments. PARTICIPANTS: Nondemented individuals with PD (N=23) experiencing walking difficulty. INTERVENTION: In the gait observation (intervention) condition, participants viewed videos of healthy and parkinsonian gait. In the landscape observation (control) condition, participants viewed videos of moving water. These tasks were completed daily for 8 days. MAIN OUTCOME MEASURES: Spatiotemporal walking variables were assessed using accelerometers in the laboratory (baseline and posttraining assessments) and continuously at home during the training period. Variables included daily activity, walking speed, stride length, stride frequency, leg swing time, and gait asymmetry. Questionnaires including the 39-item Parkinson Disease Questionnaire (PDQ-39) were administered to determine self-reported change in walking, as well as feasibility. RESULTS: At posttraining assessment, only the gait observation group reported significantly improved mobility (PDQ-39). No improvements were seen in accelerometer-derived walking data. Participants found the at-home training tasks and accelerometer feasible to use. CONCLUSIONS: Participants found procedures feasible and reported improved mobility, suggesting that observational training holds promise in the rehabilitation of walking in PD. Observational training alone, however, may not be sufficient to enhance walking in PD. A more challenging and adaptive task, and the use of explicit perceptual learning and practice of actions, may be required to effect change

    Ground Water Monitoring Project for Arkansas, Phase III

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    This report is composed of two parts. The first part is an interpretation of the pesticide and nitrate data collected in Woodruff County based on samples collected during 1994. Because there is an indication that there were hydrological differences between 1994 and 1995, and because most of the pesticide data is from 1994, this interpretive portion is restricted to 1994 data. Six wells initially sampled in 1994 that contained pesticides had continuing contamination in re-sampling in 1994 and 1995. Part II lists a seventh well in Woodruff County that contained pesticides in February and May of 199

    Neuromarketing as a scale validation tool: Understanding individual differences based on the style of processing scale in affective judgements

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    This paper revisits a well-cited and widely applied consumer scale, Style of Processing (SOP) (Childers et al., Journal of Consumer Research, 1985, 12, 125), that has been used to investigate individual differences in processing visual versus verbal information in marketing. The scale has advanced knowledge in fields related to marketing communications, product development, psychology, advertising, education and learning theories, shedding light on our understanding of consumer psychology related to persuasion, comprehension, memory, and other consumer cognitive processes involving information. In a research dialog that took place in 2008, a need for further SOP validation was suggested using a neuromarketing approach. We took this call forward and conducted an event-related-potential (ERP) experimental research study using electroencephalogram (EEG) to validate the SOP scale, focusing on differential affective processing between verbalizers and visualizers. We not only demonstrate how neuromarketing tools can be utilized to provide evidence for scale validity, providing advantages over self-reported measures; but more importantly, address issues related to understanding differential fluency effects that exist between visualizers and verbalizers. Behavioral data revealed varying reaction times to emotional stimuli of a pictorial nature. We further identify two ERP components in our data, early left anterior negativity (ELAN) and late negative slow wave (LNSW), that differentiate individual processing fluency in affective versus evaluative-based judgements. Findings confirmed the construct validity of the SOP scale and enhance our understanding of individual differences in emotional processing of pictorial information
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