The computational drawbacks of existing numerical methods have forced researchers to rely on heuristic algorithms. Heuristic methods are powerful in obtaining the solution of optimization problems. Although these methods are approximate methods (i.e. their solutions are good, but probably not optimal), they do not require the derivatives of the objective function and constraints. Also, the heur...

We investigate in this paper the optimal power allocation in an OFDM-SDMA system when some users have minimum downlink transmission rate requirements. We first solve the unconstrained power allocation problem for which we propose a fast zero-finding technique that is guaranteed to find an optimal solution, and an approximate solution that has lower complexity but is not guaranteed to converge. ...

The flexible flow-shop group scheduling problem is investigated in this paper to minimize the makespan. Two algorithms have been proposed to solve the problem with two machine centers, which have the same number of parallel machines. The first one is a heuristic algorithm. It first determines the sequence of jobs in each group by Sriskandarajah and Sethi’s approach of solving the flexible flow-...

Preventive healthcare aims at reducing the likelihood and severity of potentially life-threatening illnesses by protection and early detection. In this paper, a bi-objective mathematical model is proposed to design a network of preventive healthcare facilities so as to minimize total travel and waiting time as well as establishment and staffing cost. Moreover, each facility acts as M/M/1 queuin...

the multiple traveling salesman problem (mtsp) is a generalization of the famous traveling salesman problem (tsp), where more than one salesman is used in the solution. although the mtsp is a typical kind of computationally complex combinatorial optimization problem, it can be extended to a wide variety of routing problems. this paper presents an efficient and evolutionary optimization algorith...

Facility layout problems have been generally solved either hierarchically or integrated into other phases of plant design. In this paper, a hybrid method is introduced so that clustering and facilities layout can be simultaneously optimized. Each cluster is formed by a group of connected facilities and selection of the most appropriate cluster configuration is aimed. Since exact method by MIP i...

This paper considers the parcel hub scheduling problem (PHSP) with unequal batch size inbound trailers, which is a combinatorial optimization problem commonly found in a parcel consolidation terminal in the parcel delivery industry (PDI). The problem consists of processing a large number of inbound trailers at a much smaller number of unload docks. The parcels in the inbound trailers must be un...

[if gte mso 9]> The purpose of this paper is to consider the problem of scheduling a set of start time-dependent jobs in a two-machine flow shop, in which the actual processing times of jobs increase linearly according to their starting time. The objective of this problem is to minimize the makespan. The problem is known to be NP-hardness[ah1] ; therefore, there is no polynomial-time algorithm...

This paper presents two meta-heuristic algorithms to solve an extended portfolio selection model. The extended model is based on the Markowitz's Model, aiming to minimize investment risk in a specified level of return. In order to get the Markowitz model close to the real conditions, different constraints were embedded on the model which resulted in a discrete and non-convex solution space. ...

Generating piecewise linear approximations of digitized or "densely sampled" curves is an important problem in image processing, pattern recognition, geometric modeling, and computer graphics. Even though much attention bas been paid to the planar curve case, little work has addressed space curve approximation. In this paper, we consider how to approximate an arbitrary digitized 3-D space CUnlC...