Employing more than one supplier and splitting orders between them is a strategy employed in supply chains to lessen the lead-time risk in unstable environments. In this paper we present a multiple-sourcing inventory system with stochastic lead-times and constant demand controlled by a continuous review, reorder point-order quantity inventory policy. We consider the situation in which the order...

this work presents a simulation approach to the design and economic evaluation of fuel oil hydrotreating processes for control of so2 and nox emission in an iranian steam power plant. minimum amount of required fuel oil desulphurization was calculated from the limit of so2 emissions of power plants in two different scenarios based on (i) european and (ii) iranian so2 emission standards. based o...

PURPOSE To determine the cost savings of stereotactic core needle biopsy over open surgical biopsy in patient subgroups defined according to mammographic findings. MATERIALS AND METHODS From July 1992 through February 1995, stereotactic core needle biopsy was performed in 356 women with 405 nonpalpable breast lesions (254 were masses and 151 were calcification). Lesions were classified accord...

OBJECTIVE To estimate cost savings from emergency contraceptive pills in Canada. METHODS We modeled cost savings when a single emergency contraceptive treatment was provided after unprotected intercourse and when women were provided emergency contraceptive pills in advance. RESULTS Each dollar spent on a single treatment saved $1.19--$2.35 (in Canadian currency), depending on the regimen an...

Access network is the last mile of the communication network that connects the telecom Central Office (CO) to the residential and business customers. With the proliferation of the Internet, customer demands for bandwidth-intensive services are rapidly increasing. Access network comprises a large part of the Internet. It is a major energy consumer in the Internet due to the presence of huge numb...

This article describes a low cost retrofit technology that uses collective control of multiple rooftop air conditioning units to reduce the peak power consumption of small and medium commercial buildings. The proposed control uses a thermal model of the building and air conditioning units to select an operating schedule for the air conditioning units that maintains a temperature set point subje...

This paper develops a two-period-two-country model in which an altruistic donor faces Samaritan’s Dilemma to address two important policy questions: (i) whether foreign aid can lead to efficient level of capital investment in the recipient country and (ii) how do the form (e.g. budgetary transfers, capital transfer) and the timing of aid affect the incentives of the recipient? It finds that the...

Using a field experiment in a 401(k) plan, we measure the effect of disseminating information about peer behavior on savings. Low-saving employees received simplified plan enrollment or contribution increase forms. A randomized subset of forms stated the fraction of age-matched coworkers participating in the plan or age-matched participants contributing at least 6% of pay to the plan. We docume...

BACKGROUND Phase II cancer studies are undertaken to assess the activity of a new drug or a new treatment regimen. Activity is sometimes defined in terms of a survival probability, a binary outcome such as one-year survival that is derived from a time-to-event variable. Phase II studies are usually designed with an interim analysis so they can be stopped if early results are disappointing. Most...