University of Copenhagen, and to Ian Lange and two referees for very careful comments on an earlier version. Abstract Protected areas are employed worldwide as a means of conserving biodiversity. Unfortunately, restricting access to such areas imposes opportunity costs on local people who have traditionally relied on access to obtain resources such as fuelwood and bushmeat. We use contingent va...

this paper is in search of designing the cellular manufacturing systems (cmss) under dynamic and flexible environment. cm is proper for small-to-medium lot production environment that helps the companies to produce variable kind of productions with at least scraps. the most important benefits of cm are decline in material handling, reduction in work-in-process, reduction in set-up time, increme...

The biquadratic assignment problem BiQAP is a generalization of the quadratic assignment problem QAP It is a nonlinear integer program ming problem where the objective function is a fourth degree multivariable polynomial and the feasible domain is the assignment polytope BiQAP problems appear in VLSI synthesis Due to the di culty of this problem only heuristic solution approaches have been prop...

This paper presents a new model for project portfolio selection, paying specific attention to competence development. The model seeks to maximize a weighted average of economic gains from projects and strategic gains from the increment of desirable competencies. As a sub-problem, scheduling and staff assignment for a candidate set of selected projects must also be optimized. We provide a nonlin...

In the past decade, fuel consumption and CO2 emission have increased in the airline industry. Large CO2 footprint has a damaging effect on the environment. Global concerns over this issue has made the airline industry to be greener. Most efforts of the green airline industry are improving the fuel consumption to reduce the CO2 emission and its environmental damage. Here, we use cruise speed con...

The fleet assignment problem (FAP) assigns the type of airplane at each flight segment. Since airplane is an expensive resource, poor fleet assignment can cause a great increase in costs of airlines. There are so many consideration which should be tackled in formulation of a FAP problem, especially the parameters regarding to the airplanes. This paper presents a novel, mixed integer programing ...

In this study, we consider an airport gate assignment problem that assigns a set of aircraft to gates. The cannot be assigned any are directed apron. We aim make aircraft-gate assignments so as minimize the number apron and among usage minimizing solutions, total walking distance travelled by all passengers. is formulated mixed-integer nonlinear programming model then it linearized. A branch bo...

in this paper the real-world occurrence of the multiple-product multiple-constraint single period newsboy problem with two objectives, in which there is incremental discounts on the purchasing prices, is investigated. the constraints are the warehouse capacity and the batch forms of the order placements. the first objective of this problem is to find the order quantities such that the expected ...