47 resultados para empirical studies in ubiquitous and mobile computing
Resumo:
Facilitated by an Engineer and a Social Scientist, both of whom have expertise in Engineering Education Research and Evaluation (EERE), this interactive workshop is divided into three main sections, each one focusing on a different area of evaluation. It will build on research conducted at Aston University School of Engineering and Applied Science to explore and critique the value of introducing CDIO across the first year undergraduate curriculum. Participants will be invited to consider the pedagogical and engineering related challenges of evaluating the academic and practical value of CDIO as a strategy for learning and teaching in the discipline. An empirical approach to evaluation developed by the researchers to provide empirically grounded evidence of the pedagogical and vocational value of CDIO will form the theoretical and conceptual basis of the workshop. This approach is distinctive in that it encapsulates both engineering and social science methods of evaluation. It is also contemporaneous in nature, with the researchers acting as a ‘fly on the wall’ capturing data as the programme unfolds. Through facilitated discussion and participation, the workshop will provide colleagues with the opportunity to develop a cross-disciplinary, empirically grounded research proposal specifically for the purposes of critically evaluating CDIO. It is anticipated that during the workshop, colleagues will work together in small groups. Suitable pedagogical approaches and tools will be suggested and a purposefully developed Engineering Education Research Guide, written by the workshop facilitators, will be given to all participants to inform and support the Workshop approach.
Resumo:
Vesicular adjuvant systems composing dimethyldioctadecylammonium (DDA) can promote both cell-mediated and humoral immune responses to the tuberculosis vaccine fusion protein in mice. However, these DDA preparations were found to be physically unstable, forming aggregates under ambient storage conditions. Therefore there is a need to improve the stability of such systems without undermining their potent adjuvanticity. To this end, the effect of incorporating non-ionic surfactants, such as 1-monopalmitoyl glycerol (MP), in addition to cholesterol (Chol) and trehalose 6,6′-dibehenate (TDB), on the stability and efficacy of these vaccine delivery systems was investigated. Differential scanning calorimetry revealed a reduction in the phase transition temperature (T c) of DDA-based vesicles by ∼12°C when MP and cholesterol (1:1 molar ratio) were incorporated into the DDA system. Transmission electron microscopy (TEM) revealed the addition of MP to DDA vesicles resulted in the formation of multi-lamellar vesicles. Environmental scanning electron microscopy (ESEM) of MP-Chol-DDA-TDB (16:16:4:0.5 μmol) indicated that incorporation of antigen led to increased stability of the vesicles, perhaps as a result of the antigen embedding within the vesicle bilayers. At 4°C DDA liposomes showed significant vesicle aggregation after 28 days, although addition of MP-Chol or TDB was shown to inhibit this instability. Alternatively, at 25°C only the MP-based systems retained their original size. The presence of MP within the vesicle formulation was also shown to promote a sustained release of antigen in-vitro. The adjuvant activity of various systems was tested in mice against three subunit antigens, including mycobacterial fusion protein Ag85b-ESAT-6, and two malarial antigens (Merozoite surface protein 1, MSP1, and the glutamate rich protein, GLURP). The MP- and DDA-based systems induced antibody responses at comparable levels whereas the DDA-based systems induced more powerful cell-mediated immune responses. © 2006 The Authors.
Resumo:
The purpose of the present study was to conduct empirical research in corporate Thailand in order to (1) investigate the relationships between individual spirit at work and three employee work attitudinal variables (organisational identification, job satisfaction and psychological well-being) and three organisational outcomes (in-role performance, organisational citizenship behaviours (OCB), and turnover intentions) (2) further examine causal relations among these organisational behaviour variables with a longitudinal design (3) examine three employee work attitudes as mediator variables between individual spirit at work and three organisational outcomes and (4) explore the potential antecedents of organisational conditions that foster employee experienced individual spirit at work. The 715 completed questionnaires were received from the first wave of data collection during July 2008 and the second wave was conducted again within the same organisations and 501 completed questionnaires were received during April 2009. Data were obtained through 52 organisations which were from three types of organisations within Thailand: public organisations (N=237,185), for-profit organisations (N=244,155), and not-for-profit organisations (N=234,161). Confirmatory factor analysis of all measures used in the study and hypothesized model were tested with structural equation modeling techniques. Results were strongly supportive. In addition, although the model was invariant across rater of performance and OCB, there were differences across self report and supervisor rating. Additionally, the antecedents of organisational conditions that fostered employees experienced individual spirit at work and the implications of these findings for practice and research are discussed.
Resumo:
A 10 cm diameter four-stage Scheibel column with dispersed phase wetted packing sections has been constructed to study the hydrodynamics and mass transfer using the system toluene-acetone-water. The literature pertaining to the above extractor has been examined and the important phenomena such as droplet break-up and coalescence, mass transfer and backmixing have been reviewed. A critical analysis of the backmixing or axial mixing models and the corresponding techniques for parameter estimation was applied and an optimization technique based on Marquardt's algorithm was implemented. A single phase sampling technique was developed to estimate the acetone concentration profile in both phases along the column. Column flooding characteristics were investigated under various operating conditions and it was found that, when the impellers were located at about DI/5cm from the upper surface of the pads, the limiting flow rates increased with impeller speed. This unusual behaviour was explained in terms of the pumping effect created by the turbine impellers. Correlations were developed to predict Sauter mean drop diameters. A five-cell with backflow model was used to estimate the column performance (stage efficiency) and phases non-ideality (backflow parameters). Overall mass transfer coefficients were computed using the above model and compared with those calculated using the correlations based on single drop mechanism.
Resumo:
The profusion of performance measurement models suggested by Management Accounting literature in the 1990’s is one illustration of the substantial changes in Management Accounting teaching materials since the publication of “Relevance Lost” in 1987. At the same time, in the general context of increasing competition and globalisation it is widely thought that national cultural differences are tending to disappear, meaning that management techniques used in large companies, including performance measurement and management instruments (PMS), tend to be the same, irrespective of the company nationality or location. North American management practice is traditionally described as a contractually based model, mainly focused on financial performance information and measures (FPMs), more shareholder-focused than French companies. Within France, literature historically defined performance as being broadly multidimensional, driven by the idea that there are no universal rules of management and that efficient management takes into account local culture and traditions. As opposed to their North American brethren, French companies are pressured more by the financial institutions that fund them rather than by capital markets. Therefore, they pay greater attention to the long-term because they are not subject to quarterly capital market objectives. Hence, management in France should rely more on long-term qualitative information, less financial, and more multidimensional data to assess performance than their North American counterparts. The objective of this research is to investigate whether large French and US companies’ practices have changed in the way the textbooks have changed with regards to performance measurement and management, or whether cultural differences are still driving differences in performance measurement and management between them. The research findings support the idea that large US and French companies share the same PMS features, influenced by ‘universal’ PM models.
Resumo:
Increasingly, lab evaluations of mobile applications are incorporating mobility. The inclusion of mobility alone, however, is insufficient to generate a realistic evaluation context since real-life users will typically be required to monitor their environment while moving through it. While field evaluations represent a more realistic evaluation context, such evaluations pose difficulties, including data capture and environmental control, which mean that a lab-based evaluation is often a more practical choice. This paper describes a novel evaluation technique that mimics a realistic mobile usage context in a lab setting. The technique requires that participants monitor their environment and change the route they are walking to avoid dynamically changing hazards (much as reallife users would be required to do). Two studies that employed this technique are described, and the results (which indicate the technique is useful) are discussed.
Resumo:
Purpose - This paper aims to examine the usefulness of organizational change theory for management practice. Design/methodology/approach - The authors present an exploratory, empirical study of managers who were taught organizational change theory as part of a postgraduate degree. Building on the study findings, they analyse managers' subsequent experiences of organizational change; of how they use change theory in practice and the impact on their practice of their earlier formal study. Findings - The paper finds that the complexities of managing change in practice reflect distinctive organizational environments and cultures. The skills and knowledge which managers found most useful were those that enabled them to "make sense" of the organizational change they subsequently experienced. The main impact of their earlier studies was to prompt informative, discursive and reflective approaches to change management. Practical implications - The paper discusses the implications for future teaching of organizational change and the development of organizational change theory. Originality/value - The qualitative findings of the study add to, and help to explain, earlier research findings on the questions of how managers' experience change, how they use organizational change theory and its impact on their practice. © Emerald Group Publishing Limited.
Resumo:
This paper estimates the importance of (tariff-mediated) network effects and the impact of a consumer's social network on her choice of mobile phone provider. The study uses network data obtained from surveys of students in several European and Asian countries. We use the Quadratic Assignment Procedure, a non-parametric permutation test, to adjust for the particular error structure of network data. We find that respondents strongly coordinate their choice of mobile phone providers, but only if their provider induces network effects. This suggests that this coordination depends on network effects rather than on information contagion or pressure to conform to the social environment.
Resumo:
G-protein coupled receptors (GPCRs) constitute the largest class of membrane proteins and are a major drug target. A serious obstacle to studying GPCR structure/function characteristics is the requirement to extract the receptors from their native environment in the plasma membrane, coupled with the inherent instability of GPCRs in the detergents required for their solubilization. In the present study, we report the first solubilization and purification of a functional GPCR [human adenosine A<inf>2Ainf> receptor (A<inf>2Ainf>R)], in the total absence of detergent at any stage, by exploiting spontaneous encapsulation by styrene maleic acid (SMA) co-polymer direct from the membrane into a nanoscale SMA lipid particle (SMALP). Furthermore, the A<inf>2Ainf>R-SMALP, generated from yeast (Pichia pastoris) or mammalian cells, exhibited increased thermostability (∼5°C) compared with detergent [DDM (n-dodecyl-β-D-maltopyranoside)]-solubilized A<inf>2Ainf>R controls. The A<inf>2Ainf>R-SMALP was also stable when stored for prolonged periods at 4°C and was resistant to multiple freeze-thaw cycles, in marked contrast with the detergent-solubilized receptor. These properties establish the potential for using GPCR-SMALP in receptor-based drug discovery assays. Moreover, in contrast with nanodiscs stabilized by scaffold proteins, the non-proteinaceous nature of the SMA polymer allowed unobscured biophysical characterization of the embedded receptor. Consequently, CD spectroscopy was used to relate changes in secondary structure to loss of ligand binding ([3H]ZM241385) capability. SMALP-solubilization of GPCRs, retaining the annular lipid environment, will enable a wide range of therapeutic targets to be prepared in native-like state to aid drug discovery and understanding of GPCR molecular mechanisms.
Resumo:
This paper aims to analyse the impact of regulation in the financial performance of the Water and Sewerage companies (WaSCs) in England and Wales over the period 1991–2008. In doing so, a panel index approach is applied across WaSCs over time to decompose unit-specific index number-based profitability growth as a function of the profitability, productivity and price performance growth achieved by benchmark firms, and the catch up to the benchmark firm achieved by less productive firms. The results indicated that after 2000 there is a steady decline in average price performance, while productivity improves resulting in a relatively stable economic profitability. It is suggested that the English and Welsh water regulator is now more focused on passing productivity benefits to consumers, and maintaining stable profitability than it was in earlier regulatory periods. This technique is of great interest for regulators to evaluate the effectiveness of regulation and companies to identify the determinants of profit change and improve future performance, even if sample sizes are limited.
Resumo:
This study identifies and investigates the potential use of in-eye trigger mechanisms to supplement the widely available information on release of ophthalmic drugs from contact lenses under passive release conditions. Ophthalmic dyes and surrogates have been successfully employed to investigate how these factors can be drawn together to make a successful system. The storage of a drug-containing lens in a pH lower than that of the ocular environment can be used to establish an equilibrium that favours retention of the drug in the lens prior to ocular insertion. Although release under passive conditions does not result in complete dye elution, the use of mechanical agitation techniques which mimic the eyelid blink action in conjunction with ocular tear chemistry promotes further release. In this way differentiation between passive and triggered in vitro release characteristics can be established. Investigation of the role of individual tear proteins revealed significant differences in their ability to alter the equilibrium between matrix-held and eluate-held dye or drug. These individual experiments were then investigated in vivo using ophthalmic dyes. Complete elution was found to be achievable in-eye; this demonstrated the importance of that fraction of the drug retained under passive conditions and the triggering effect of in-eye conditions on the release process. Understanding both the structure-property relationship between drug and material and in-eye trigger mechanisms, using ophthalmic dyes as a surrogate, provides the basis of knowledge necessary to design ocular drug delivery vehicles for in-eye release in a controllable manner.