1,540 research outputs found

    Clustering in a Data Envelopment Analysis Using Bootstrapped Efficiency Scores

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    This paper explores the insight from the application of cluster analysis to the results of a Data Envelopment Analysis of productive behaviour. Cluster analysis involves the identification of groups among a set of different objects (individuals or characteristics). This is done via the definitions of a distance matrix that defines the relationship between the different objects, which then allows the determination of which objects are most similar into clusters. In the case of DEA, cluster analysis methods can be used to determine the degree of sensitivity of the efficiency score for a particular DMU to the presence of the other DMUs in the sample that make up the reference technology to that DMU. Using the bootstrapped values of the efficiency measures we construct two types of distance matrices. One is defined as a function of the variance covariance matrix of the scores with respect to each other. This implies that the covariance of the score of one DMU is used as a measure of the degree to which the efficiency measure for a single DMU is influenced by the efficiency level of another. An alternative distance measure is defined as a function of the ranks of the bootstrapped efficiency. An example is provided using both measures as the clustering distance for both a one input one output case and a two input two output case.

    Inferences for the Extremum of Quadratic Regression Models

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    Quadratic functions are often used in regression to infer the existence of an extremum in a relationship although tests of the location of the extremum are rarely performed. We investigate the construction of the following confidence intervals: Delta, Fieller, estimated first derivative, bootstrapping, Bayesian and likelihood ratio. We propose interpretations for the unbounded intervals that may be generated by some of these methods. The coverage of the confidence intervals is assessed by Monte Carlo; the Delta and studentized bootstrap can perform quite poorly. Of all the methods, the first derivative method is easiest to implement.Inverted U-Shaped, turning point, Fieller method, Delta method, 1st derivative function, Bayesian, Likelihood ratio, Bootstrap.

    Tests of Inference for Dummy Variables in Regressions with Logarithmic Transformed Dependent Variables

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    The interpretation of dummy variables in regressions where the dependent variable is subject to a log transformation has been of continuing interest in economics. However, in the main, these earlier papers do not deal with the inferential aspects of the parameters estimated. In this paper we compare the inference implied by the hypotheses tested on the linear parameter estimated in the model and the tests applied to the proportional change that this parameter implies. An important element in this analysis is the asymmetry introduced by the log transformation. Suggestions are made for the appropriate test procedure in this case. Examples are presented from some common econometric applications of this model in the estimation of hedonic price models and wage equations.Hypothesis tests;lognormal distribution; measures of proportional change; wage equation; hedonic price model

    Inclusive design: making packaging easier to open for all

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    Social equality demands a shift in attitude, away from treating older people and people with disabilities as special cases requiring special design solutions, and towards enabling them to have equal access to any product or service through a more inclusive approach to the design of buildings, public spaces and, more recently, products and services. This is not just important for social equality but also for business growth through new products and services and through creating wider potential markets. Consumer packaging is a field in which many people, including young able bodied people, often struggle in relation to openability. Until now, the main thrust of inclusive design in the consumer packaging field has been driven by art and design disciplines, focusing on the shape and ergonomics of the packaging or cognitive solutions in order to make them easier to open. This approach does not always work first time and a time consuming, materially expensive trial and error process often ensues. This paper outlines all the arguments for inclusive design, stressing the importance for both consumers and business. This paper also outlines an engineering design approach for inclusive design that uses real human factors as design limits, resulting in packaging that will be easily opened by all it’s end users without the expensive trial and error approach that has been used up to this point in time. The example of the Roll-On-Pilfer-Proof (ROPP) closure system is used in this paper

    The 'inclusive engineering' approach: an optimum diameter for ease of opening

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    Social equality demands a shift in attitude, away from treating older people and people with disabilities as special cases requiring special design solutions, and towards enabling them to have equal access to any product or service through a more inclusive approach to the design of buildings, public spaces and, more recently, products and services. This is not just important for social equality but also for business growth through new products and services and through creating wider potential markets. It is a sad fact of life that as people get older there is a massive decline in their strength and dexterity. Due to the fact that we handle and manipulate so many things throughout our life time, from the tiniest and most dexterous of tasks to heavy manual labour, this decline is very noticeable in our hands. In nearly all the actions that we use our hands for there is some form of grip used in order to hold onto an object before manipulating it. The natural decrease in strength combined with debilitating illness such as arthritis, means that hand grip strength or finger grip strength are very seriously affected. This has a knock on affect of making it much harder to twist things or pinch and pull things. Therefore there is often a measured decrease in torque strength with age caused not so much by a decrease in wrist strength but more often than not by a decrease in grip strength. Consumer packaging is a field in which many people, including young able bodied people, often struggle in relation to openability. Yet it is present in even the most mundane and neccessary of every day tasks such as eating, cleaning teeth, even drinking. Human interation with consumer packaging requires a wide range of hand dexterity and strength and a variety of differing hand actions. This paper looks at just one such set of actions; that used to open bottles and jars. It outlines all the arguments for inclusive design, stressing the importance for both consumers and business. This paper also outlines an engineering design approach for inclusive design that uses real human factors as design limits, resulting in packaging that will be easily opened by all it’s end users without the expensive trial and error approach that has been used up to this point in time. This paper examines the affect of grip strength on the required trorque to open closures and concludes that there is an optimum diameter for ease of opening that will decrease the required strength to open such closures

    Crystal structure of NiFe(CO)5[tris(pyridyl-meth-yl)aza-phosphatrane]: a synthetic mimic of the NiFe hydrogenase active site incorporating a pendant pyridine base.

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    The reaction of Ni(TPAP)(COD) {where TPAP = [(NC5H4)CH2]3P(NC2H4)3N} with Fe(CO)5 resulted in the isolation of the title heterobimetallic NiFe(TPAP)(CO)5 complex di-μ-carbonyl-tricarbon-yl[2,8,9-tris-(pyridin-2-yl-meth-yl)-2,5,8,9-tetra-aza-1-phosphabi-cyclo-[3.3.3]undeca-ne]ironnickel, [FeNi(C24H30N7P)(CO)5]. Characterization of the complex by 1H and 31P NMR as well as IR spectroscopy are presented. The structure of NiFe(TPAP)(CO)5 reveals three terminally bound CO mol-ecules on Fe0, two bridging CO mol-ecules between Ni0 and Fe0, and TPAP coordinated to Ni0. The Ni-Fe bond length is 2.4828 (4) Å, similar to that of the reduced form of the active site of NiFe hydrogenase (∼2.5 Å). Additionally, a proximal pendant base from one of the non-coordinating pyridine groups of TPAP is also present. Although involvement of a pendant base has been cited in the mechanism of NiFe hydrogenase, this moiety has yet to be incorporated in a structurally characterized synthetic mimic with key structural motifs (terminally bound CO or CN ligands on Fe). Thus, the title complex NiFe(TPAP)(CO)5 is an unique synthetic model for NiFe hydrogenase. In the crystal, the complex mol-ecules are linked by C-H⋯O hydrogen bonds, forming undulating layers parallel to (100). Within the layers, there are offset π-π [inter-centroid distance = 3.2739 (5) Å] and C-H⋯π inter-actions present. The layers are linked by further C-H⋯π inter-actions, forming a supra-molecular framework

    A framework for understanding the characteristics of complexity in biology

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    Understanding the functioning of natural systems is not easy, although there is general agreement that understanding complex systems is an important goal for science education. Defining what makes a natural system complex will assist in identifying gaps in research on student reasoning about systems. The goal of this commentary is to propose a framework that explicitly defines the ways in which biological systems are complex and to discuss the potential relevance of these complexity dimensions to conducting research on student reasoning about complexity in biology classrooms. We use an engineering framework for dimensions of complexity and discuss how this framework may also be applied to biological systems, using gene expression as an example. We group dimensions of this framework into components, functional relationships among components, processes, manifestations, and interpretations within biological systems. We explain four steps that discipline-based education researchers can use to apply these dimensions to explore student reasoning about complex biological systems

    Fair Warning | 21-20206

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    Fair Warning Part Number: 21-20206 Previous Part Number HL-206 Price: $1.90 Voicing: SSA Lyrics By: Jenny Joseph Music By: Shirley W. McRaehttps://digitalcommons.butler.edu/jca_scores/1381/thumbnail.jp

    Where Would You Turn For Help? Older Adults’ Knowledge and Awareness of Community Support Services

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    Community support services (CSSs) enable persons coping with health or social problems to maintain the highest possible level of social functioning and quality of life. Access to these services is challenging because of the multiplicity of small agencies providing these services and the lack of a central access point. A review of the literature revealed that most service awareness studies are marred by acquiescence bias. To address this issue, service providers developed a series of 12 vignettes to describe common situations faced by older adults for which CSSs might be appropriate. In a telephone interview, 1152 older adults were presented with a series of vignettes and asked what they would do in that situation. They were also asked about their most important sources of information about CSSs. Findings show awareness of CSSs varied by the situation described and ranged from a low of 1% to 41%. The most important sources of information about CSSs included informational and referral sources, the telephone book, doctor’s offices, and through word of mouth.Community Support Services, awareness, knowledge, acquiencence bias, vignette methodology
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