Project scheduling   Net present value   We consider a project scheduling problem with permitted tardiness and discrete time/resource trade-offs under maximum net present value objective. In this problem, a project consists of a set of sequential phases such that each phase contains one or more sub-projects including activities interrelated by finish-start-type precedence relations with a t...

Sex investment ratios in populations of bumblebees are male biased, which contradicts theoretical predictions. Male-biased investment ratios in eusocial Hymenoptera are assumed to be non-stable for both the queen and her workers. In this paper, we show that male-biased sex allocation does not necessarily decrease ¢tness in the bumblebee Bombus terrestris. A male-biased investment ratio can be t...

during the implementation, construction projects usually encounter situation that considerably affects the project scheduling and cost. this study aims at using an improved version of the harmony search algorithm (hsa) to schedule resource constrained construction projects. this model is formulated as a global optimization problem. it will determine the duration of each activity to minimize the...

The Dynamic and Stochastic Knapsack Problem (DSKP) is de ned as follows: Items arrive according to a Poisson process in time. Each item has a demand (size) for a limited resource (the knapsack) and an associated reward. The resource requirements and rewards are jointly distributed according to a known probability distribution and become known at the time of the item's arrival. Items can be eith...

Consider a ®rm that markets multiple products, each manufactured using several resources representing various types of capital and labor, and a linear production technology. The ®rm faces uncertain product demand and has the option to dynamically readjust its resource investment levels, thereby changing the capacities of its linear manufacturing process. The cost to adjust a resource level eith...

The current paradigm of Content Distribution Networks (CDN) deployment requires heavy infrastructure investment since a large number of servers have to be deployed over a wide area. To overcome this difficulty, we propose a new paradigm where future CDNs are to be deployed over a leased server infrastructure. This paradigm shift changes the object placement problem in current CDNs to a combined...