731 research outputs found
Actuator fault tolerance for aWAM-V catamaran with azimuth thrusters
No full textIn this chapter, we present a fault-tolerant control scheme for an over-actuated unmanned surface vehicle (USV) equipped with two azimuth thrusters. The scheme manages the most common actuator faults, i.e., loss of efficiency of the thruster and lock-in-place of the azimuth angle. The scheme is based on a three-layer architecture: a heuristic-based control policy for proper reference generation, a control law for the vehicle dynamics to achieve speed tracking of the generated reference, and a control allocation level for optimally redistributing the control efforts among the thrusters even in presence of actuator faults and failures. The control allocation and the control policies are the main focus of the chapter, since their reconfiguration capabilities allow tolerance with respect to actuator failures. On the contrary, the control law does not depend on the health status of the system. The scheme is then tested in simulation, using a nonlinear model of a wave adaptive modular vessel catamaran
Directive speech acts in the New Testament
No full textDanuta Pytel-Pandey, WrocławThis article discusses the directive speech acts in the New Testament. The
author presents examples of such acts from the New Testament Scriptures, and
then carries out their pragmalinguistic [email protected]
Similarities between 2D and 3D convection for large Prandtl number
No full textUsing direct numerical simulations of Rayleigh-B\'enard convection (RBC), we perform a comparative study of the spectra and fluxes of energy and entropy for large and infinite Prandtl numbers in two (2D) and three (3D) dimensions. We observe close similarities between the 2D and 3D RBC, in particular the kinetic energy spectrum , and the entropy spectrum exhibits a dual branch with a dominant spectrum. We showed that the dominant Fourier modes in the 2D and 3D flows are very close
Evaluation and analysis of impact of subsidies on small scale renewable energy technologies dissemination: a case study of Nepal
No full textThe report has analysed the status of rural electrification using renewable energy technologies (RETs) and the current subsidy delivery modality of RETs in Nepal. As the Government of Nepal is subsidizing small scale renewable energy projects, it is important to evaluate and analyse the programme to make sure that a programme is running in an effective and efficient way while reaching the target group.
During the course of the research, primary information collected from the field has been compiled using appropriate tools/software (such as MS Office) and analyzed. Different sets of questionnaires were prepared, targeting different personnel ranging from the users’ level to the government policy level. The field survey methods include field observations of RETs installations and operations along with interviews with selected users on a random sampling basis to identify barriers to subsidy delivery and possible measures to overcome these barriers; to determine user satisfaction level and time period for subsidy delivery mechanisms.
The report started with the country background information and the rationale behind the study. This is followed by the literature review and information on the current status of small scale RETs in the country. Next it deals with the organizational structure and current subsidy delivery modality of RETs in the country. The evaluation of the effectiveness of the subsidy with the current subsidy delivery modality has been analyzed based on six parameters; Targets and Achievements, Impact of RETs, Subsidy Delivery System Efficiency, Transparency, Sustainability and Effectiveness.
The research shows that the subsidized government program has been successful in achieving its goal to provide basic energy services in rural areas through RETs in terms of its quantitative target. Although the subsidized program is successful in electrifying the rural communities via RETs, the poorest of the poor families are still excluded from the subsidy. The program seems to benefit more the rich and upper middle class families rather than the poor families for which the subsidy was intended. The high capital cost and long subsidy delivery process are the main important reasons for this failure. The author has proposed a new modality which might overcome the time barriers and bureaucratic process in the subsidy delivery mechanism and will decrease the lead time. This will in turn help to reduce the operational cost of the private companies and will encourage more players to enter the market, increase competition and result in lower system costs.
After identifying gaps in the current subsidy delivery modality, the project report ends with the recommendation of a new modality improving the current modality and filling the gaps identified. As this study has some limitations, as described in chapter one, the scope of further works has been listed at the end
Implementing the market approach to enterprise support - an evaluation of ten matching grant schemes
No full textDeveloping viable new business is critical to recovery, and long-term growth, especially in transition economies. There has been a long history of public support of enterprise development, starting with centralized state agency initiatives, but moving more recently to decentralized instruments for development of the business services market. The window of time during which the benefits of intervention are likely to be greatest: when a market is in its infancy, and its development is constrained by uncertainty, and lack of information. Interventions for enterprise support should be demand-responsive, and flexibly organized. In some circumstances, centralized assistance may still be effective, but it is generally better to use competitive private service providers responding to enterprises'changing needs. The main task is to stimulate the private services sector, improving its capacity to respond to the demands of new, and expanding private enterprises. Support for enterprises has tended to be either free, or heavily subsidized. But such subsidies can be justified only if interventions efficiently supply goods. Providing technical, and management know-how can be a public good if it generates externalities- if, for example, know-how benefits can be disseminated at proportionately low additional cost. Any subsidy for an intervention should be temporary, and should be phased out when the main objective of intervention is achieved - that is, when the market takes off. Grants should generally be for know-how, not for equipment. There may be a case for unbundling the know-how component of loans (including feasibility studies, and follow-up expert services) for grant funding. A package combining loans and grants - through a single financial institution, or through separate institutions - may work provided safeguards can be put in place to prevent perverse use of grants. The matching grant model, which is used increasingly in the World Bank, and elsewhere, is one solution - but it must be justified, and carefully designed. After evaluating ten matching grant funds, the author concludes that performance is mixed. Best practice models are needed. Ensuring economic benefits requires proactive management, with clear objectives of market facilitation ("making a market"). And it requires a balance between rapid grant approval procedures, and careful selection of services for grants.Economic Theory&Research,Decentralization,Enterprise Development&Reform,Environmental Economics&Policies,Banks&Banking Reform,Health Economics&Finance,Banks&Banking Reform,Economic Theory&Research,Environmental Economics&Policies,ICT Policy and Strategies
Parameters quantification of genetic algorithm
No full textThis paper presents the importance of parameters tuning in global optimization algorithms. The primary objective of an experiment is to recognize the process. The experiments are carried out to learn the effect of various factors at different levels. Hence, identifying the optimal parameters setting is important for robust design. One of the most popular global optimization algorithms: genetic algorithm is considered in this study. The domain of inquiry is travelling salesman problem. The present study employs the Taguchi method that involves the use of an orthogonal array in the estimation of the factors. Taguchi approach has been widely applied in experimental design for problems with multiple factors. The use of Taguchi design is a novel idea—leads to efficient algorithms—can find a satisfactory solution in a few iterations, which improves the convergence speed and reduces the cost. Experimental results show that the Taguchi design is less sensitive to initial value of parameters. Two versions of genetic algorithms (with tuning and without tuning) are implemented. The analysis shows the superiority of genetic algorithm with tuning over genetic algorithm without tuning.</p
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