We present sufficient conditions under which thermal generators can be aggregated in mixed-integer linear programming (MILP) formulations of the unit commitment (UC) problem, while maintaining feasibility and optimality for the original disaggregated problem. Aggregating thermal generators with identical characteristics (e.g., minimum/maximum power output, minimum up/down-time, and cost curves)...

It is well known that the combination of clock skew scheduling and delay insertion can achieve the lower bound of sequential timing optimization. Previous works focus on the minimization of required inserted delay. However, from the viewpoint of design closure, minimizing the number of inserted buffers is also very important. In this paper, we propose an MILP (mixed integer linear programming) ...

Among the hardest Mixed-Integer Linear Programming (MILP) problems, the ones that exhibit a symmetric nature are particularly important in practice, as they arise in both theoretical and practical combinatorial optimization problems. A theoretical concept that generalizes the notion of symmetry is that of dominance. This concept, although known since a long time, is typically not used in genera...

Abstract We consider the problem of scheduling under demand uncertainty a multiproduct batch plant represented through the State Task Network. Given a scheduling horizon consisting of several time-periods in which product demands are placed, the objective is to select a schedule that maximizes the expected profit. We present a multistage stochastic Mixed Integer Linear Programming (MILP) model,...

This paper investigates modeling methods with thermal network representation under the scope of optimal design and operation Distributed Multi-Energy System (D-MES). Two approaches are compared: A Mixed‐Integer Linear Programming (MILP) optimization model a district heating (DHN) simulation model. The MILP was developed for simultaneous layout, sizing, locations energy generation storage techno...

Postal logistics has a complex transportation network for efficient mail delivery. Therefore, a postal logistics network consists of various functional sites with a hybrid hub-and-spoke structure. More specifically, there are multiple Delivery & Pickup Stations (D&PSs), multiple Mail Processing Centers (MPCs), and one Exchange Center (EC). In this paper, we develop two mathematical models with ...

In this paper, based on the cyclic scheduling formulation of Schilling and Pantelides [22], we propose a continuous time mixed integer linear programming (MILP) formulation for the cyclic scheduling of a mixed plant, i.e. a plant composed of batch and continuous tasks. The cycle duration is a variable of the model and the objective is to maximize productivity. By using strengthening techniques ...

In this paper, we present a novel method for scheduling smart appliances and batteries, in order to reduce both the electricity bill and the CO2 emissions. Mathematically, the scheduling problem is posed as a multi-objective Mixed Integer Linear Programming (MILP), which can be solved by using standard algorithms. A case study is performed to assess the performance of the proposed scheduling fr...

A novel formulation for combined scheduling and control of multi-product, continuous chemical processes is introduced in which nonlinear model predictive control (NMPC) and noncyclic continuous-time scheduling are efficiently combined. A decomposition into nonlinear programming (NLP) dynamic optimization problems and mixed-integer linear programming (MILP) problems, without iterative alternatio...

Production planning and scheduling in the steel industry are challenging problems due to large number of products being produced. This work deals with scheduling of the continuous casting of steelmaking, i.e. determination of charge sequence in each casting machine. Since a full-space model Mixed-Integer Linear Programming (MILP) approach is computationally intractable for long term continuous ...