A simple, fast, and effective heuristic for the single-machine total weighted tardiness problem

We consider the single-machine total weighted tardiness problem (TWT) where a set of n jobs with general weights w_1,…, w_n, integer processing times p_1,…, p_n, and integer due dates d_1,…, d_n has to be scheduled non-preemptively. If C_j is the completion time of job j then T_j = max(0, C_j - d_j) denotes the tardiness of this job. The objective is to find a schedule S^{*}_{WT} that minimizes the weighted sum of the tardiness costs of all jobs computed as \sum_{j=1}^{n} w_j T_j. This problem is known to be unary NP-hard. Our goal is to design a constructive heuristic for this problem that yields excellent feasible solutions in short computational times by exploiting the structural properties of a preemptive relaxation

A Survey On Multi Trip Vehicle Routing Problem

The vehicle routing problem (VRP) and its variants are well known and greatly explored in the transportation literature. The vehicle routing problem can be considered as the scheduling of vehicles (trucks) to a set of customers under various side constraints. In most studies, a fundamental assumption is that a vehicle dispatched for service finishes its duty in that scheduling period after it returns back to the depot. Clearly, in many cases this assumption may not hold. Thus, in the last decade some studies appeared in the literature where this basic assumption is relaxed, and it is allowed for a vehicle to make multiple trips per period. We consider this new variant of the VRP an important one with direct practical impact. In this survey, we define the vehicle routing problem with multiple trips, define the current state-of-the-art, and report existing results from the current literature

Raising the tax ratio by reining in the "Tax-Breaks": An agenda for action.

Taxation

Tax breaks for the small scale sector: An appraisal.

Small scale sector ; Taxation

A strong preemptive relaxation for weighted tardiness and earliness/tardiness problems on unrelated parallel machines

Research on due date oriented objectives in the parallel machine environment is at best scarce compared to objectives such as minimizing the makespan or the completion time related performance measures. Moreover, almost all existing work in this area is focused on the identical parallel machine environment. In this study, we leverage on our previous work on the single machine total weighted tardiness (TWT) and total weighted earliness/tardiness (TWET) problems and develop a new preemptive relaxation for the TWT and TWET problems on a bank of unrelated parallel machines. The key contribution of this paper is devising a computationally effective Benders decomposition algorithm for solving the preemptive relaxation formulated as a mixed integer linear program. The optimal solution of the preemptive relaxation provides a tight lower bound. Moreover, it offers a near-optimal partition of the jobs to the machines, and then we exploit recent advances in solving the non-preemptive single machine TWT and TWET problems for constructing non-preemptive solutions of high quality to the original problem. We demonstrate the effectiveness of our approach with instances up to 5 machines and 200 jobs

Raising the Tax Ratio by Reining in the 'Tax Breaks': An Agenda for Action

The increase in direct taxes has not been able to offset the decline that resulted from the reduction in customs tariff and decline in excise revenue. The task facing the policymakers now is to explore ways in which the tax ratio can be pushed up without going back on the basic elements of the reforms carried out so far, namely, without raising the rates or resorting to distortionary taxation. The task has acquired urgency with government’s obligation to abide by the deficit targets set under the Fiscal Responsibility and Budget Management Act and the expenditure commitments of the United Progressive Alliance. Under the restructuring plan drawn up by the Twelfth Finance Commission (TFC), incorporating the FRBM commitments of the union government, the targets set for revenue mobilisation are modest. Given the constraints, the options are: one, tightening the administration and two, widening the base not so much in terms of the number of taxpayers brought under the net but the content of what is subjected to tax (which, no doubt, will have its impact on numbers as well). To improve the revenue productivity of the tax system in the short-run without tinkering with the rates is to take a look at the base of the major union taxes viz., income tax, excise and customs, and explore how they can be widened keeping in view the constraints. The main thrust of such an exercise has to be a review of various exemptions and concessions – the ‘tax breaks’ – that abound in all the taxes and erode the base and their revenue productivity.taxation, directe taxes, indirect taxes, income tax, excise tax, customs duties, exemptions, revenue productivity, Economics, Public Finance, Macroeconomics, Indian Economy