This paper examines an economic production quantity (EPQ) model with rework and service level constraint. First, we prove that the expected overall costs for an imperfect EPQ model with backlogging permitted is less than or equal to that of the one without backlogging. Secondly, the relationship between “imputed backorder cost” and maximal shortage level is derived for decision-making on whethe...

In this paper we study the computational complexity of the extended minimum cost homomorphism problem (Min-Cost-Hom) as a function of a constraint language, i.e. a set of constraint relations and cost functions that are allowed to appear in instances. A wide range of natural combinatorial optimisation problems can be expressed as extended Min-Cost-Homs and a classification of their complexity w...

In this paper we describe a benchmark generator for a family of cost aware resource constraints. These constraints have been introduced in the context of electricity cost minimization, but can also be applied for other use cases like manpower scheduling. None of the existing resource constraint benchmarks include a cost element, we therefore created our own test generator to evaluate the qualit...

We motivate and introduce an extension of the well-known cumulative constraint which deals with time and volume dependent cost of resources. Our research is primarily interested in scheduling problems under time and volume variable electricity costs, but the constraint equally applies to manpower scheduling when hourly rates differ over time and/or extra personnel incur higher hourly rates. We ...

We consider Constraint Satisfaction Problems in which constraints can be initially incomplete, where it is unknown whether certain tuples satisfy the constraint or not. We assume that we can determine such an unknown tuple, i.e., find out whether this tuple is in the constraint or not, but doing so incurs a known cost, which may vary between tuples. We also assume that we know the probability o...

This paper describes a methodology for transmission expansion planning (TEP) within a deregulated electricity market. Two objective functions including investment cost (IC) and congestion cost (CC) are considered. The proposed model forms a bi-level optimization problem in which upper level problem represents an independent system operator (ISO) making its decisions on investment while in the l...

Artificial intelligence (AI) techniques are successfully applied in various phases of software development life cycle. One of the most significant and innovative AI applications is using constraint-based techniques for automation of software testing. Testing is nowadays the primary way to improve the reliability of software. Software testing accounts for about 50% of the total cost of software ...

A data warehouse uses multiple materialized views to efficiently process a given set of queries. These views are accessed by read-only queries and need to be maintained after updates to base tables. Due to the space constraint and maintenance cost constraint, the materialization of all views is not possible. Therefore, a subset of views needs to be selected to be materialized. The problem is NP...

Constraint-based routing gradually becomes an essential enabling mechanism for a variety of emerging network services such as virtual private networking and QoS support. A number of recent works have recognized its signiicance and investigated many aspects of the operation of constraint based routing and in particular its variant that is concerned with determining paths for requests with specii...

In this article we extend Shiryaev’s quickest change detection formulation by also accounting for the cost of observations used before the change point. The observation cost is captured through the average number of observations used in the detection process before the change occurs. The objective is to select an on–off observation control policy that decides whether or not to take a given obse...