Abstract In 1998, Hu and Liu developed a strongly polynomial algorithm for solving the inverse arborescence problem that aims at minimally modifying given cost-function on edge-set of digraph D so an input spanning becomes cheapest one. this note, we develop conceptually simpler along with new min–max formula minimum modification cost-function. The approach is based link to theorem simple (two-...

The product rate variation problem minimizes the variation in the rate at which different models of a common base product are produced on the assembly lines with the assumption of negligible switch-over cost and unit processing time for each copy of each model. The assumption of significant setup and arbitrary processing times forces the problem to be a two phase problem. The first phase determ...

the product rate variation problem minimizes the variation in the rate at which different models of a common base product are produced on the assembly lines with the assumption of negligible switch-over cost and unit processing time for each copy of each model. the assumption of significant setup and arbitrary processing times forces the problem to be a two phase problem. the first phase determ...

In this paper we generalize the notion of polynomial-time approximation scheme preserving reducibility, called PTAS-reducibility, introduced in a previous paper. As a rst application of this generalization, we prove the APX-completeness of a polynomially bounded optimization problem, that is, an APX problem whose measure function is bounded by a polynomial in the length of the instance and such...

n this paper, at first the  concept of caputo fractionalderivative is generalized on time scales. then the fractional orderdifferential equations are introduced on time scales. finally,sufficient and necessary conditions are presented for the existenceand uniqueness of solution of initial valueproblem including fractional order differential equations.

In this paper , we prove the first approximate max-flow min-cut theorem for undirected mul t i commodi ty flow. We show tha t for a feasible flow to exist in a mul t icommodi ty problem, it is sufficient t ha t every cut ' s capacity exceeds its demand by a factor of O(logClogD), where C is the sum of all finite capacities and D is the sum of demands . Moreover, our theorem yields an a lgor i t...

In view of Min-Min algorithm prefers scheduling small tasks and Max-Min algorithm prefers scheduling big tasks led to the problem of load imbalance in cloud computing, a new algorithm named Min-Max is proposed. Min-Max makes good use of time of greedy strategy, small tasks and big tasks are put together for scheduling in order to solve the problem of load imbalance. Experimental results show th...

background and objectives: visit length is a crucial aspect of patient-physician relationship that its inadequacy can negatively influence the treatment efficiency. studies on visit length and the factors influencing it are limited in developing countries. thus, the objective of this study was to survey this variable at provincial level, and provide data on factors affecting it.   methods: a sa...