The optimal design of risers for castings has been the subject of numerous investigations and this paper determines the optimal dimensions when Chvorinov’s rule for solidification is obeyed by both the riser and casting and solidification time is the only constraint involved .This problem can be formulated to minimize the riser volume subject to the constraint that the riser solidification time...

In this work an approach is proposed to solve geometric programming problems under uncertainty. The proposed approach derives the lower and upper bounds of the objective of geometric programming problems with fuzzy parameters. A pair of two-level mathematical programs is formulated to calculate the lower and upper bounds of the objective value. The solution is in a range. Two illustrative examp...

This paper presents solution technique of geometric programming with fuzzy parameters to solve structural model. Here we are considered all fuzzy parameters as a generalized fuzzy number i.e. generalized triangular fuzzy number and generalized trapezoidal fuzzy number. Here material density of the bar, permissible stress of each bar and applied load are fuzzy numbers. We use geometric programmi...

In this paper we consider production economic and cost related yield rate in a JIT (Just in Time) system. Based on the traditional EPQ (Economic Production Quantity) model, we establish the relation between cost and yield rate. The geometric programming approach is applied in our model to solve this optimizing posynomials problem. A numerical example is carried out to verify the proposed model....

This paper describes a novel optimization-based approach to conflict resolution in air traffic control, based on geometric programming. The main advantage of the approach is that Geometric Programs (GPs) can also capture various metering directives issued by the traffic flow management level, in contrast to most recent methods focusing purely on aircraft separation issues. GPs can also account ...

In this paper we describe the DCEL system: a geometric software package which implements a polyhedral programming environment. This package enables fast proto-typing of geometric algorithms for polyhedra or for polyhedral surfaces. We provide an overview of the system's functionality and demonstrate its use in several applications.

We review the recent progress in the design of e cient algorithms for various problems in geometric optimization. The emphasis in this survey is on the techniques used to attack these problems, such as parametric searching, geometric alternatives to parametric searching, prune-and-search techniques for linear programming and related problems, and LP-type problems and their e cient solution.

Hybrid automatic repeat 1 request (HARQ) is a key enabler for ultrareliable communications. This paper optimizes transmit power the initial transmission and subsequent retransmissions of HARQ with either incremental redundancy or Chase combining, aiming to minimize expected energy consumption given target outage probability latency. The main challenge due fact that complicated function variable...

This column will publish short (ranging from just a few paragraphs to ten or so pages), lively and intriguing computer-related mathematics vignettes. These vignettes or snapshots should illustrate ways in which computer environments have transformed the practice of mathematics or mathematics pedagogy. They could also include puzzles or brain teasers involving the use of computers or computation...