- Current Project

- Vehicle Routing

- We study the vehicle routing problem with skill sets. We are given a set of customers, a set of vehicles, and a skill set for each vehicle along with a skill requirement for each customer. A vehicle can serve a customer if the customer's skill requirement belongs to the skill set of the vehicle. The goal is to design a set of routes with minimum total cost, such that the route for each vehicle starts and ends at a depot, and the skill requirement for customer belongs to the skill set of the vehicle.
- Bobby Chan, Ehsan Iranmanesh, Kamyar Khodamoradi, Ramesh Krishnamurti, Arash Rafiey, and Vladyslav Sokol

- Past Projects

- Level of Repair Analysis for defense logistics support planning (LORA)

- A complex engineering system containing (perhaps thousands) of subsystem and components is given. For each subsystem and each component (each subsystem contains some components) there is a possible repair decisions. The goal is to determine an optimal provision of repair and maintenance facilities to minimize overall life-cycle costs (which is of interest in

UK and US military). An earlier result [A combinatorial approach to level of repair analysis, European J. Oper. Res. 129 (2001) 242–251] developed certain branch-and-bound heuristics.

We model the problem as a minimum cost homomorphism problem in bipartite graphs and show that the problem is indeed solvable in polynomial time. - G. Gutin, Arash Rafiey, M. Tso, and A. Yeo

- A complex engineering system containing (perhaps thousands) of subsystem and components is given. For each subsystem and each component (each subsystem contains some components) there is a possible repair decisions. The goal is to determine an optimal provision of repair and maintenance facilities to minimize overall life-cycle costs (which is of interest in
- Coordinated scheduling problem with time window constraints

- We consider selecting and scheduling of several jobs on a single machine with strictly enforced time windows constraints on the start-times of each job. We demonstrate how to develop network-based algorithms to sustain the desired work in process (WIP) profile in a manufacturing environment. Short-term production targets are used to coordinate decentralized local schedulers and to make the objectives of specific areas in-line with the chain objectives (Designed and implemented an efficient algorithm in C++).
- P.Jula and Arash Rafiey

- Computationally hard aggregation and voting rules

- The goal is to design new algorithms based on integer programming, and approximation techniques to find the winner(s) of computationally hard aggregation and ranking rules fast.
- Ehsan Iranmanesh and Ramesh Krishnamurti

- The scheduling and b-matching Proble

- We consider the problem of scheduling the shifts for workers in a factory. We improve the current best known algorithm and design faster algorithms to solve this problem optimally.
- Binay Batacharya, Ehsan Iranmanesh and Ramesh Krishnamurti