An integrated control/structure design method using multi-objective optimization

The benefits are demonstrated of a multiobjective optimization based control structure integrated design methodology. An application of the proposed CSI methodology to the integrated design of the Spacecraft COntrol Lab Experiment (SCOLE) configuration is presented. Integrated design resulted in reducing both the control performance measure and the mass. Thus, better overall performance is achieved through integrated design optimization. The mutliobjective optimization approach used provides Pareto optimal solutions by unconstrained minimization of a differentiable KS function. Furthermore, adjusting the parameters gives insight into the trade-offs involved between different objectives

Returns and Economic Efficiency of Sheep Farming in Semi-arid Regions: A Study in Rajasthan

The economics of sheep-farming and its economic efficiency have been reported using field level data collected from the semi-arid regions of Rajasthan in 2005. The net return per average flock of 54 has been found Rs 25000 per year. The sheep-farming activity attracts labour employment of 581 mandays per annum, more than three-fourths of which is engaged in grazing. The female labour has been found to contribute 12 per cent of the total labour requirement. The main items of expenditure are feed and fodder, veterinary care, hired labour charges and interest. The major modes of return are sale of live-animals, wool, milk and manure. The overall average economic efficiency has been found to be 75 per cent, indicating that the returns could be improved by another 25 per cent with the present resource-use level. More than two-thirds of the farmers have been recorded distributed in the economic efficiency range of 70-85 per cent. The resource-poor farmers have been observed to realize higher economic efficiency than their rich counterparts. The major factor responsible for inducing improvement in efficiency has been identified as membership in farmers’ organisations, which probably provides them better access to technical knowledge and improves their bargaining power.Livestock Production/Industries,

Trends, Determinants and Constraints of Temporary Sheep Migration in Rajasthan — An Economic Analysis

The study has analysed the temporary migration of sheep as a response to the demand-supply disequilibrium of fodder and water and has explored its trends, determinants and constraints by using the data collected from rural areas of semi-arid Rajasthan. About 32 per cent of the farmers in the study area undertake temporary sheep migration. The migrating farmers have higher holding size of sheep, goat and buffaloes and are better in terms of adoption of improved sheep management practices than non-migrant farmers. The flock size, potential household labour supply and credit absorption behaviour have been reported to positively affect the odds of migration. The farmers face various en-route problems during migration, the major ones being increased morbidity, non-availability of veterinary medicines, resistance from local persons, theft and missing of sheep. The net return per animal per year has been found slightly higher in case of the non-migrant sheep flocks. The study has argued that migration of livestock is to be viewed as a method of production and adaptive mechanism evolved over the years. Efforts to sendentarise migrants without providing alternate fodder sources or productive assets of gainful employment may not be fruitful. In order to sustain the livelihood of the sheep farmers, institutional intervention to enhance accessibility to fodder and feed, veterinary services and strengthening of the extension services is needed.Sheep migration, Rajasthan, Sheep farming, Agricultural and Food Policy, Q11,

Degradation of Common Pastures: An Economics Perspective of its Impact on Livestock Farming and Coping Strategies

The study has examined the farmers’ perception regarding deterioration of pasturelands, its impact on livestock farming and the factors affecting farmers’ willingness to contribute to a participatory pasture development programme. It is based on the primary data collected from sheep farmers of semi-arid and arid regions of Rajasthan in the year 2008. A large proportion of farmers have perceived deterioration of the pastureland which has resulted in the reductions of wool yield per animal (18%), body weight of sheep (20%) and age of disposal of lambs (45%). The major coping mechanisms adopted by the farmers have been identified are: reduction in total livestock holding (86%), reduction in sheep flock size (55%), grazing on alternative fodder sources (30%), increased frequency of migration (59%), increased duration of migration (41%), and disposal of male lambs at an early age (76%). The reduction of pastureland has resulted in cost escalation for sheep farming, particularly for the landless and small farmers. Double Bounded Dichotomous Choice (DBDC) method of Willingness to Pay (WTP) has been used to analyze the factors affecting the association of farmers with a participatory pasture development programme. The bivariate probit model estimated using this data has indicated that the expected cost and the concerns regarding inequitable distribution of benefits affect WTP negatively, whereas flock size affects it positively. The farmers in the arid region have been found more forthcoming towards a participatory management strategy. The study has highlighted the importance of awareness generation about the participatory management strategy and its incorporation as a component of livestock development programmes.Agricultural and Food Policy,

Elasto-multi-body dynamics of internal combustion engines with thin-shell elastohydrodynamic journal bearings

This thesis describes problems associated with noise and vibration concern in internal combustion engines as the result of a growing trend in the development of modern vehicular engines with high power to light weight ratios. There are a plethora of vibration concerns. These are owed to the increasing combustion forces in lean burn engines and the progressive use of materials of durable, but light-weight construction. The latter has come about as a result of a need to reduce the inertial imbalances. These features have resulted in achieving fuel efficiency. Although the primary aims in high output power and structural integrity have been largely achieved, these have culminated in an assortment of sources of noise and vibration, chiefly among them those associated with signature output of the combustion process. For the common four stroke engines, the contributory sources are at half-engine order multiples, referred to as engine "roughness". A holistic approach is to incorporate reduced engine roughness contributions as an integral part of engine design and development. The aim of this thesis is to create a methodology for fundamental design evaluation and analysis of engine dynamics, which comprises rigid body inertial dynamics of engine assembly, the elasto-dynamics of flexible and compliant components and applied and reactive forces in such a complex assembly. [Continues.

Decentralized Distributed Expert Assisted Learning (D2EAL) approach for cooperative target-tracking

This paper addresses the problem of cooperative target tracking using a heterogeneous multi-robot system, where the robots are communicating over a dynamic communication network, and heterogeneity is in terms of different types of sensors and prediction algorithms installed in the robots. The problem is cast into a distributed learning framework, where robots are considered as 'agents' connected over a dynamic communication network. Their prediction algorithms are considered as 'experts' giving their look-ahead predictions of the target's trajectory. In this paper, a novel Decentralized Distributed Expert-Assisted Learning (D2EAL) algorithm is proposed, which improves the overall tracking performance by enabling each robot to improve its look-ahead prediction of the target's trajectory by its information sharing, and running a weighted information fusion process combined with online learning of weights based on a prediction loss metric. Theoretical analysis of D2EAL is carried out, which involves the analysis of worst-case bounds on cumulative prediction loss, and weights convergence analysis. Simulation studies show that in adverse scenarios involving large dynamic bias or drift in the expert predictions, D2EAL outperforms well-known covariance-based estimate/prediction fusion methods, both in terms of prediction performance and scalability