Answer Set Planning Under Action Costs

Recently, planning based on answer set programming has been proposed as an approach towards realizing declarative planning systems. In this paper, we present the language Kc, which extends the declarative planning language K by action costs. Kc provides the notion of admissible and optimal plans, which are plans whose overall action costs are within a given limit resp. minimum over all plans (i.e., cheapest plans). As we demonstrate, this novel language allows for expressing some nontrivial planning tasks in a declarative way. Furthermore, it can be utilized for representing planning problems under other optimality criteria, such as computing ``shortest'' plans (with the least number of steps), and refinement combinations of cheapest and fastest plans. We study complexity aspects of the language Kc and provide a transformation to logic programs, such that planning problems are solved via answer set programming. Furthermore, we report experimental results on selected problems. Our experience is encouraging that answer set planning may be a valuable approach to expressive planning systems in which intricate planning problems can be naturally specified and solved

Three levels of metric for evaluating wayfinding

Three levels of virtual environment (VE) metric are proposed, based on: (1) users’ task performance (time taken, distance traveled and number of errors made), (2) physical behavior (locomotion, looking around, and time and error classification), and (3) decision making (i.e., cognitive) rationale (think aloud, interview and questionnaire). Examples of the use of these metrics are drawn from a detailed review of research into VE wayfinding. A case study from research into the fidelity that is required for efficient VE wayfinding is presented, showing the unsuitability in some circumstances of common metrics of task performance such as time and distance, and the benefits to be gained by making fine-grained analyses of users’ behavior. Taken as a whole, the article highlights the range of techniques that have been successfully used to evaluate wayfinding and explains in detail how some of these techniques may be applied

ASAP: The After Salesman Problem

The customer contacts taking place after a sales transaction and the services involved are of increasing importance in contemporary business models. The responsiveness to service requests is a key dimension in service quality and therefore an important succes factor in this business domain. This responsiveness is of course highly dependent on the operational scheduling or dispatching decisions made in the often dynamic service settings. We consider the problem of optimizing responsiveness to service requests arriving in real time. We consider three models and formulations and present computational results on exact solution methods. The research is based on practical practical work done with the largest service organization in The Netherlands.operations research and management science;

ANWB automates and improves repair men dispatching

ANWB, the Dutch automobile association, provides assistance, car repair andreplacement services to its nearly 4 million members. ANWB services around 1.3 millionrequests per year in The Netherlands. Historically, the operational planning process ofassigning requests to service men was regionally organized, and human planners solvedthe sometimes large and hectic planning situations in real time. At a national level, some50 planners were required to do the job, and the quality of the planning and operationswere largely unknown. In a large business process reengineering project, ANWBredesigned the planning processes, leveraging state of the art IT and operations researchtechniques. As a result, the 24/7 planning processes are smoothened, can be executed byas few as 14 planners who work at a national level, and the operational planning andperformance have improved. As new competitors entered the market, ANWB has beenable to sustain its extraordinary high customer ratings and market share, while adaptingits proposition to the competitive prices dictated by the market.Economics (Jel: A)