8,304 research outputs found
A Lindley-type equation arising from a carousel problem
In this paper we consider a system with two carousels operated by one picker.
The items to be picked are randomly located on the carousels and the pick times
follow a phase-type distribution. The picker alternates between the two
carousels, picking one item at a time. Important performance characteristics
are the waiting time of the picker and the throughput of the two carousels. The
waiting time of the picker satisfies an equation very similar to Lindley's
equation for the waiting time in the PH/U/1 queue. Although the latter equation
has no simple solution, we show that the one for the waiting time of the picker
can be solved explicitly. Furthermore, it is well known that the mean waiting
time in the PH/U/1 queue depends on to the complete interarrival time
distribution, but numerical results show that, for the carousel system, the
mean waiting time and throughput are rather insensitive to the pick-time
distribution.Comment: 10 pages, 1 figure, 19 reference
Decision systems : the relation between problem specification and mathematical analysis
In this paper it is demonstrated that automated support for decision making of a tactical or strategic nature requires a solver-independent medium for describing decision situations. Such a medium may be specific for one environment, but it is also possible to develop media for certain types of environments. By using such a medium one obtains a decoupling of problem formulation and method of analysis. This makes it possible to use (parts of) the problem formulation as input for different types of models. Such problem formulations may provide mathematical models themselves, although they might also contain some less formal features. The decoupling makes it possible to choose problem formulations which are much closer to the original decision situation than would otherwise be possible with formulations in terms of a preselected solver. The argumentation is illustrated by treating a language for specifying goods flow problems in some detail. This language is based on timed coloured Petri-nets
Decision rules in Markovian decision processes with incompletely known transition probabilities
Decision support for natural resource management; models and evaluation methods
When managing natural resources or agrobusinesses, one always has to deal with autonomous processes. These autonomous processes play a core role in designing model-based decision support systems. This chapter tries to give insight into the question of which types of models might be used in which cases. It does so by formulating a rough categorization of decision problems and providing many examples. Particular attention is given to the role of statistical learning theory, which may be used to replace mathematical modeling by training with example
On the design of a real-time volume rendering engine
An architecture for a Real-Time Volume Rendering Engine (RT-VRE) is given, capable of computing 750 × 750 × 512 samples from a 3D dataset at a rate of 25 images per second. The RT-VRE uses for this purpose 64 dedicated rendering chips, cooperating with 16 RISC-processors. A plane interpolator circuit and a composition circuit, both capable to operate at very high speeds, have been designed for a 1.6 micron VLSI process. Both the interpolator and composition circuit are back from production. They have been tested and both complied with our specifications
The ALICE Transition Radiation Detector
In this talk an overview of the ALICE TRD is presented. The ALICE TRD consists of 540 individual detector modules with a total of 1.2 million readout channels. It allows electron identification above a momentum of 1 GeV/c and is capable of providing a very fast and efficient trigger on electrons with large transverse momentum pt. It will operate in a very high multiplicity environment. The rapidity density of charged particles in collisions of Pb nuclei at ps = 5:5 ATeV is expected to be as high as dN/dy = 8000
- …