65 resultados para system design


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Ethics is an important element in all aspects of Information Systems (IS), from the design, operation and delivery of such systems. Most research has focused upon traditional IS system design and the associated ethical issues. There are many aspects of ethics that can impact the design and operation of Information Systems, but online system design is often overlooked. The paper will focus upon a design approach that allows for the design on online systems and considers the ethical issues. The approach was developed and validated in regards to a tertiary environment.

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A well designed runner and feeding system should produce castings with minimal defects and low pour weight. This thesis investigates how the filling regime and solidification of the mould influences defects in the castings produced from that mould. Design guidelines to reduce such defects are proposed and tested. An existing shrinkage fault in a Grey Iron disc brake casting is simulated using a commercial finite-difference computer program. Three criteria are used to predict the defect and the effect of changes to the feeder geometry. Critical Fraction Solidification analysis is used to determine whether the feeder remains in liquid contact with the casting during solidification and this approach is shown to correctly predict the presence or absence of porosity* The feeder block is extended below the ingate of the casting to improve liquid contact between the casting and feeder without significantly increasing the feeder mass. Plant trials confirm the change to the feeder eliminates the porosity defect. The runner system and mould venting for a thin walled Ductile Iron casting are investigated. Trials show that by setting the total mould vent area to be greater than the net ingate area of the castings, the cold-shut frequency is halved. A method for runner system design based on peak linear flow velocity in the runner during mould filling is proposed. A new pressurised runner system produces castings with significantly fewer defects and reduced pour weight when runner areas are designed to maintain peak velocity below 1 m/s. Peak velocity and magnesium levels are demonstrated to be critical factors in the elimination of cold-shut defects. A pressurised runner system is also shown to isolate inclusion defects from castings more effectively than an unpressurised system. From this work, a technique is proposed which allows the yield of an existing runner and feeder system for iron castings to be improved with confidence in the results.

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One of the major challenges of MIS activities is the difficulty in measuring the effectiveness of delivered systems. The principal purpose of my research is to explore this field in order to develop an instrument by which to measure such effectiveness. Conceptualisation of Information System (IS) Effectiveness has been substantially framed by DeLone and McLean's (1992) Success; Model. But with the innovation in Information Technology (IT) over the past decade, and the constant pressure in IT to improve performance, there is merit in undertaking a fresh appraisal of the issue. This study built on the model of IS Success developed by DeLone and MeLean, but was broadened to include related research from the domains of IS, Management and Marketing. This analysis found that an effective IS function is built on three pillars: the systems implemented; the information held and delivered by these systems; and, the service provided in support of the IS function. A common foundation for these pillars is the concept of stakeholder needs. In seeking to appreciate the effectiveness: of delivered IS applications in relation to the job performance of stakeholders, this research developed an understanding of what quality means in an IT context I argue that quality is a more useful criterion for effectiveness than the more customary measures of use and user satisfaction. Respecification of the IS Success Model was then proposed. The second phase of the research was to test this model empirically through judgment panels, focus groups and interviews. Results consistently supported the structure and components of the respecified model. Quality was determined as a multi-dimensional construct, with the key dimensions for the quality of delivered IS differing from those used in the research from other disciplines. Empirical work indicated that end-user stakeholders derived their evaluations of quality by internally evaluating perceived performance of delivered IS in relation to their expectations for such performance. A short trial explored whether, when overt measurement of expectations was concurrent with the measurement of perceptions, a more revealing appraisal of delivered IS quality was provided than when perceptions alone were measured. Results revealed a difference between the two measures. Using the New IS Success Model as the foundation, and drawing upon the related theoretical and empirical research, an instrument was developed to measure the quality/effectiveness of delivered IS applications. Four trials of this instrument, QUALIT, are documented. Analysis of results from preliminary trials indicates promise in terms of business value: the instrument is simple to administer and has the capacity to pinpoint areas of weakness. The research related to the respecification of the New IS Success Model and the associated empirical studies, including the development of QTJALIT, have both contributed to the development of theory about IS Effectiveness. More precisely, my research has reviewed the components of an information system, the dimensions comprising these components and the indicators of each, and based upon these findings, formulated an instrument by which to measure the effectiveness of a delivered IS.

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Many organizations make use of information system development methodologies to guide their staff in developing computerised information systems. This thesis contributes to methodology engineering research by introducing a number of important innovations in methodology fragment architectures.

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Transmit power control is an important consideration in the cellular system design since it increases system capacity, improves QoS and reduces multi-user interference. In this paper, an adaptive power control design based on the identification of the underlying pathloss of the fading channel is presented. Making power control decisions based on the measured received power allows to model the fading channel pathloss dynamics with a Hidden Markov Model. Applying the online HMM identification algorithm enables accurate estimation of the real pathloss which ensures efficient performance of the suggested power control scheme.

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Sensor Networks have applications in diverse fields. They can be deployed for habitat modeling, temperature monitoring and industrial sensing. They also find applications in battlefield awareness and emergency (first) response situations. While unique addressing is not a requirement of many data collecting applications of wireless sensor networks, it is vital for the success of applications such as emergency response. Data that cannot be associated with a specific node becomes useless in such situations. In this work we propose a novel dynamic addressing mechanism for wireless sensor networks that are not location-aware. The scheme enables successful reuse of addresses in event-driven wireless sensor networks introducing minimal latencies and efficiently addressing packet loss. It also eliminates the need for network-wide Duplicate Address Detection (DAD) to ensure uniqueness of network level addresses.

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This research is related to the user-centred design and use of Virtual Environment (VE) training systems. A multidimensional user-centred systematic training evaluation framework that combines ideas from human-computer interaction, training, education and psychology was proposed, which contributes to better design and evaluation of VE user interfaces.

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A mathematical model of a solar module is presented. This model takes into account solar model temperature and solar radiation. The experimental data of a solar module under natural environment condition (NEC) have been obtained to determine the model parameters. The experimental results are compared with those calculated by using a mathematical model. It shows that the mathematical model accurately simulates the current-voltage characteristics of the solar module under the NEC and therefore is suitable for photovoltaic system design and performance analysis.

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A sustainable building regards energy use and greenhouse gas emissions as major components, and its sustainability is within a larger context of benefits about productivity, efficiency, health and safety, and serviceability. An intelligent building requires a quality building automation system design which increases productivity, reduces operational costs and protects the people using the facilities. Council House 2 (CH2) is claimed to change the way Australia approaches ecologically sustainable design and construction. Its building intelligence can be evaluated by energy and water efficiency and quality of indoor environments that elevate productivity and lower operational costs. This paper uses triangulation techniques, based upon the "Building Intelligence Quotient" by the Continental Automated Buildings Association (CABA) and "Green Star Rating" by the Green Building Council of Australia (GBCA), to cross-verify CH2’s sustainability and intelligence. The author examines 18 design reports and 10 research papers to case-study the effectiveness and efficiency of CH2 and concludes that it is not just another sustainable construction but an intelligent building per se. By leveraging the existing knowledge base of green rating, building professions can measure the intelligence without "reinventing the wheel".

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Creating a highly programmable surface operating at relatively high speed and in real time is an area of research with many challenges. Such a system has applications in the field of optical telescopes, product manufacturing, and giant 3D-screens and billboards for advertising and artwork. This paper covers certain aspects of a keynote presentation at ISDT 2010 including system design, modularity, programmability and the system control intelligence. An overview of the system architecture, actuator design, electronics and distributed control will provide an insight into how the system is controlled and self-tuned for a number of applications. A simulation environment that has been developed to streamline system reconfiguration will also be presented, demonstrating translation of complex mathematical functions into 3D shapes virtually before being displayed on the physical surface.

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Background
The successful Greater Green Triangle Diabetes Prevention Program (GGT DPP), a small implementation trial, has been scaled-up to the Victorian state-wide ‘Life!’ programme with over 10,000 individuals enrolled. The Melbourne Diabetes Prevention Study (MDPS) is an evaluation of the translation from the GGT DPP to the Life! programme. We report results from the preliminary phase (pMDPS) of this evaluation.
Methods
The pMDPS is a randomised controlled trial with 92 individuals aged 50 to 75 at high risk of developing type 2 diabetes randomised to Life! or usual care. Intervention consisted of six structured 90-minute group sessions: five fortnightly sessions and the final session at 8 months. Participants underwent anthropometric and laboratory tests at baseline and 12 months, and provided self-reported psychosocial, dietary, and physical activity measures. Intervention group participants additionally underwent these tests at 3 months. Paired t tests were used to analyse within-group changes over time. Chi-square tests were used to analyse differences between groups in goals met at 12 months. Differences between groups for changes over time were tested with generalised estimating equations and analysis of covariance.
Results
Intervention participants significantly improved at 12 months in mean body mass index (−0.98 kg/m2, standard error (SE) = 0.26), weight (−2.65 kg, SE = 0.72), waist circumference (−7.45 cm, SE = 1.15), and systolic blood pressure (−3.18 mmHg, SE = 1.26), increased high-density lipoprotein-cholesterol (0.07 mmol/l, SE = 0.03), reduced energy from total (−2.00%, SE = 0.78) and saturated fat (−1.54%, SE = 0.41), and increased fibre intake (1.98 g/1,000 kcal energy, SE = 0.47). In controls, oral glucose at 2 hours deteriorated (0.59 mmol/l, SE = 0.27). Only waist circumference reduced significantly (−4.02 cm, SE = 0.95).

Intervention participants significantly outperformed controls over 12 months for body mass index and fibre intake. After baseline adjustment, they also showed greater weight loss and reduced saturated fat versus total energy intake.

At least 5% weight loss was achieved by 32% of intervention participants versus 0% controls.
Conclusions
pMDPS results indicate that scaling-up from implementation trial to state-wide programme is possible. The system design for Life! was fit for purpose of scaling-up from efficacy to effectiveness.

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In this paper, a robust learning control is developed for a class of single input single output (SISO) nonlinear systems with T-S fuzzy model. It is seen that the proposed sliding mode learning control with the powerful Lipshitz-like condition can guarantee the stability, convergence and robustness of the closed-loop system without involving any assumptions on uncertain system dynamics. In addition, theconcept that the local system with the maximum membership function dominates the system dynamic behaviours helps to greatly simplify the control system design. It will be further seen that the continuous learning control ensures the advantage of chattering-free that may occur in conventional sliding mode systems. Simulation examples are presented to demonstrate the effectiveness of the proposed learning control through the comparison with the H-infinity control.

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Modeling and simulation is commonly used to improve vehicle performance, to optimize vehicle system design, and to reduce vehicle development time. Vehicle performances can be affected by environmental conditions and driver behavior factors, which are often uncertain and immeasurable. To incorporate the role of environmental conditions in the modeling and simulation of vehicle systems, both real and artificial data are used. Often, real data are unavailable or inadequate for extensive investigations. Hence, it is important to be able to construct artificial environmental data whose characteristics resemble those of the real data for modeling and simulation purposes. However, to produce credible vehicle simulation results, the simulated environment must be realistic and validated using accepted practices. This paper proposes a stochastic model that is capable of creating artificial environmental factors such as road geometry and wind conditions. In addition, road geometric design principles are employed to modify the created road data, making it consistent with the real-road geometry. Two sets of real-road geometry and wind condition data are employed to propose probability models. To justify the distribution goodness of fit, Pearson's chi-square and correlation statistics have been used. Finally, the stochastic models of road geometry and wind conditions (SMRWs) are developed to produce realistic road and wind data. SMRW can be used to predict vehicle performance, energy management, and control strategies over multiple driving cycles and to assist in developing fuel-efficient vehicles.

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Any organisation that captures personal data in Canada for processing is deemed tohave a ‘real and substantial connection’ to Canada and thus fall within thejurisdiction of the Personal Information Protection and Electronic Documents Act(PIPEDA) and of the Office of the Privacy Commissioner of Canada (OPC). Whathas been the experience of enforcing Canadian privacy protection law on US-basedsocial networking services? We analyse some of the high-profile enforcement actionsby the Privacy Commissioner. We also test compliance through an analysis of theprivacy policies of the top 23 SNSs operating in Canada and through the use of accessto personal information requests. Our analysis suggests that non-compliance iswidespread, and is explained by the countervailing conceptions of jurisdictioninherent in corporate policy and technical system design.

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Growing popularity in parametric urbanism has prompted investigation into the effects digital parametric systems have had on the way we design. This research proposes a new method of Problem Centric System Design, encouraging working methods that are led by both the designer’s aspirations and the requirements of the design problem.