We study concurrent processes modelled as workflow Petri nets extended with resource constrains. We define structural criteria for the correctness of such models based on traps and siphons. We also define a behavioural correctness criterion called soundness: given a sufficient initial number of resources, all cases in the net are guaranteed to terminate successfully, no matter which schedule is...

The resource constrained shortest path problem (CSP) asks for the computation of a least cost path obeying a set of resource constraints. The problem is NP-complete. We give theoretical and experimental results for CSP. In the theoretical part we present the hull approach, a combinatorial algorithm for solving a linear programming relaxation and prove that it runs in polynomial time in the case...

Resource leveling is a variant of resource-constrained project scheduling in which a non-regular objective function, the resource availability cost, is to be minimized. We present a branch-and-price approach together with a new heuristic to solve the more general turnaround scheduling problem. Besides precedence and resource constraints, also availability periods and multiple modes per job have...

In the recent decade, numerous researchers have proposed extended version of scheduling problem named as multimode resource constrained scheduling problem (MMRCSP), claiming it to be a more practical way of capturing production characteristics. However, this flexibility comes with increased complexity. The present work proposes a framework for such multimode scheduling problems in order to prov...

DTLS is becoming the de facto standard for communication security in the Internet of Things. In order to run the DTLS protocol one needs to establish keys between the communicating devices. The default method of key establishment requires X.509 certificates and a Public Key Infrastructure, an approach which is often too resource consuming for small IoT devices. DTLS also supports the use of pre...

In this paper we describe an extension of the Resource-Constrained Project Scheduling Problem (RCPSP). A literature review is presented to place our research in its proper context. The problem presented here belongs to the class of the optimization scheduling problems with multi-level (or multi-mode) activities. This means that the activities can be scheduled at different modes, each mode using...

A recurring problem in project management involves the allocation of scarce resources to the individual jobs comprising the project. In many situations such as audit-staff scheduling, timetabling, and course scheduling, the resources correspond to individuals (skilled labour). This naturally leads to an assignment-type project scheduling problem, i.e. a project has to be performed by assigning ...

during the implementation, construction projects usually encounter situation that considerably affects the project scheduling and cost. this study aims at using an improved version of the harmony search algorithm (hsa) to schedule resource constrained construction projects. this model is formulated as a global optimization problem. it will determine the duration of each activity to minimize the...