A survey of preventive maintenance models for stochastically deteriorating single-unit systems

A survey of the research done on preventive maintenance is presented. The scope of the present survey is on the research published after the 1976 paper by Pierskalla and Voelker [98]. This article includes optimization models for repair, replacement, and inspection of systems subject to stochastic deterioration. A classification scheme is used that categorizes recent research into inspection models, minimal repair models, shock models, or miscellaneous replacement models.     

Fund Transfers – African Terrorists Blend Old and New: Hawala and Satellite Telecommunications

Attempts to disrupt the flow of funds through Africa used to finance terrorism have been hindered by terrorists utilizing satellite telecommunications in conjunction with hawala, an ancient system of fund transfers based on trust. This arrangement leaves few records for tracing transactions, a task made even more difficult by the general paucity of investigators trained in the languages commonly used for hawala. Acquiring personnel with the appropriate linguistic skills is one of the steps agencies can take to reduce the terrorist financing that occurs through this unique blend of an ancient system with modern technology.     

Amidst the chaos a small force for stability: Somalia's business community

Though parts of Somalia appear mired in intractable conflict, both domestic and foreign trade continues. As a result amidst the conflict, corruption, and chaos Somalia's business community is a small force for peace and stability. Thus, efforts directed at enhancing the business community, possibly via the Transitional Federal Government or its successor, could play a small role in improving the situation in this strategically poised country with a very entrepreneurial population. However, such success is far from certain, and numerous other factors besides a strengthened business community would have to occur for Somalia even to begin the journey on the long road to recovery.     

An M/M/1 queue with a general bulk service rule

A model of an M/M/1, bulk queue with service rates dependent on the batch size is developed. The operational policy is to commence service when at least L customers are available with a maximum batch size of K. Arriving customers are not allowed to join in-process service. The solution procedure utilizes the matrix geometric methodology and reduces to obtaining the inverse of a square matrix of dimension K + 1 - L. For the case where the service rates are not batch size dependent, the limiting probabilities can be written in closed form. A numerical example illustrates the variability of the system cost as a function of the minimum batch service size L.     

A note on a computational model for a data/voice communication queueing system

Certain types of communication nodes can be viewed as multichannel queueing systems with two types of arrival streams. Data arrivals are characterized by high arrival and service rates and have the ability to queue if all service channels are busy. Voice arrivals have small arrival and service rates and do not have the ability to wait when the channels are full. Computational procedures are presented for obtaining the invariant probabilities associated with the queueing model.     

A Deal with the Devil: Issues in Offering Joseph Kony Amnesty to Resolve the Conflict in Uganda

Peace talks have commenced between the Ugandan Government and the Lord's Resistance Army (LRA), which has committed countless atrocities during the nearly 20 years it has tried to overthrow the government. The head of the LRA, Joseph Kony, has been offered amnesty by the government in the hope that peace will ensue. This raises the question of whether a government should forego the pursuit of justice in order to prevent further bloodshed.