background over the past few decades diabetes has emerged as an important non-communicable disease in subsaharan africa (ssa). sight loss from diabetic retinopathy (dr) can be prevented with screening and early treatment. the objective of this paper is to outline the required actions and considerations in the planning and development of dr screening services.   methods a multiple-case study app...

Simple lower and upper bounds on mean cycle time in stochastic acyclic fork-join queueing networks are derived using a (max,+)algebra based representation of network dynamics. The behaviour of the bounds under various assumptions concerning the service times in the networks is discussed, and related numerical examples are presented. Key-Words: (max,+)-algebra, dynamic state equation, acyclic fo...

A vehicle routing problem is a significant problem that has attracted great attention from researchers in recent years. The main objectives of the vehicle routing problem are to minimize the traveled distance, total traveling time, number of vehicles and cost function of transportation. Reducing these variables leads to decreasing the total cost and increasing the driver's satisfaction level. O...

In order to develop appropriate queueing models that can be applied to efficiently provide good service in a service system with arrivals by appointment, we carefully consider what stochastic arrival process models may be appropriate. We provide a guideline or template for creating stochastic arrival process models by carefully examining appointment and arrival data from an endocrinology clinic...

Quantifying the performance of component-based or serviceoriented systems is a complex task, e.g., it is non-trivial to calculate the end-to-end quality of service of a composite Web service. An established approach to reason about such systems in general is the use of coordination models, which can provide a formal basis for both their verification and implementation. An example of such a mode...

Stochastic Petri Nets (SPN) are usually designed to support exponential distributions only, with the consequence that their modeling power is restricted to markovian systems. In recent years, some attempts have been appeared in the literature aimed to de ne SPN models with generally distributed ring times. A particular subclass, called Deterministic and Stochastic Petri Nets (DSPN), combines in...

The analysis of stochastic loss networks has long been of interest in computer and communications networks and is becoming important in the areas of service and information systems. In traditional settings computing thewell-knownErlang formula for blocking probabilities in these systems becomes intractable for larger resource capacities. Using compound point processes to capture stochastic vari...