Applications – OR and Management Sciences

Resource Allocation for Contingency Planning: An Inexact Bundle Method for Stochastic Optimization

Categories Nonsmooth Optimization, Production and Logistics, Stochastic Programming Tags , , , ,

Resource allocation models in contingency planning aim to mitigate unexpected failures in supply chains due to disruptions with rare occurrence but disastrous consequences. This paper formulates this problems as a two-stage stochastic optimization with a risk-averse recourse function, and proposes a novel computationally tractable solution approach. The method relies on an inexact bundle method and … Read more

Convexification of Queueing Formulas by Mixed-Integer Second-Order Cone Programming: An Application to a Discrete Location Problem with Congestion

Categories (Mixed) Integer Nonlinear Programming, Applications - OR and Management Sciences, Second-Order Cone Programming

Mixed-Integer Second-Order Cone Programs (MISOCPs) form a nice class of mixed-inter convex programs, which can be solved very efficiently due to the recent advances in optimization solvers. Our paper bridges the gap between modeling a class of optimization problems and using MISOCP solvers. It is shown how various performance metrics of M/G/1 queues can be … Read more

Stochastic Dynamic Programming Using Optimal Quantizers

Categories Applications - OR and Management Sciences, Dynamic Programming, Stochastic Programming

Multi-stage stochastic optimization is a well-known quantitative tool for decision-making under uncertainty, which applications include financial and investment planning, inventory control, energy production and trading, electricity generation planning, supply chain management and similar fields. Theoretical solution of multi-stage stochastic programs can be found explicitly only in very exceptional cases due to the complexity of the … Read more

Index Policies and Performance Bounds for Dynamic Selection Problems

Categories Applications - OR and Management Sciences, Dynamic Programming Tags , , , ,

We consider dynamic selection problems, where a decision maker repeatedly selects a set of items from a larger collection of available items. A classic example is the dynamic assortment problem with demand learning, where a retailer chooses items to offer for sale subject to a display space constraint. The retailer may adjust the assortment over … Read more

The forwarder planning problem in a two-echelon network

Categories Approximation Algorithms, Transportation Tags , ,

This paper is motivated by the case of a forwarder in dealing with inland transportation planning from a seaport, where inbound containers from the sea are filled with pallets, which have different destinations in the landside. Although this forwarder does not have or control any vehicle, he is required to plan the assignment of containers … Read more

Tightness of a new and enhanced semidefinite relaxation for MIMO detection

Categories Global Optimization Applications, Semi-definite Programming, Telecommunications Tags , , ,

In this paper, we consider a fundamental problem in modern digital communications known as multi-input multi-output (MIMO) detection, which can be formulated as a complex quadratic programming problem subject to unit-modulus and discrete argument constraints. Various semidefinite relaxation (SDR) based algorithms have been proposed to solve the problem in the literature. In this paper, we … Read more

A multi-period production and distribution optimization model for radiopharmaceuticals

Categories (Mixed) Integer Nonlinear Programming, Biomedical Applications, Production and Logistics Tags , , ,

This paper addresses the manufacturing and distribution of short-lived radio-pharmaceuticals which are mainly used in diagnostic imaging studies. We develop a mixed integer nonlinear optimization model that is flexible enough to capture the complex underlying nuclear physics of the production process of fludeoxyglucose (FDG), which is widely used in oncology and cardiology, as well as … Read more

NeatWork, a tool for the design of gravity-driven water distribution systems for poor rural communities

Categories Applications - OR and Management Sciences, Applications - Science and Engineering Tags , , ,

NeatWork is an advanced optimization and simulation tool for the design of purely gravity-driven water distribution systems aiming at delivering clean water to poor rural communities. The exclusion of any adjustable devices, such as pumps and valves, for controlling pressures and flows is motivated by two main reasons: firstly, the system should be as simple … Read more

Energy Technology Environment Model with Smart Grid and Robust Nodal Electricity Prices

Categories Applications - OR and Management Sciences, Applications - Science and Engineering

This paper deals with the modeling of power flow in a transmission grid within the multi-sectoral multi-energy long-term regional energy model ETEM-SG. This extension of the model allows a better representation of demand response for flexible loads triggered by nodal marginal cost pricing. To keep the global model in the realm of linear program- ming … Read more