An Experimental Nexos Laboratory Using Virtual Xinu

The Nexos Project is a joint effort between Marquette University, the University of Buffalo, and the University of Mississippi to build curriculum materials and a supporting experimental laboratory for hands-on projects in computer systems courses. The approach focuses on inexpensive, flexible, commodity embedded hardware, freely available development and debugging tools, and a fresh implementation of a classic operating system, Embedded Xinu, that is ideal for student exploration. This paper describes an extension to the Nexos laboratory that includes a new target platform composed of Qemu virtual machines. Virtual Xinu addresses two challenges that limit the effectiveness of Nexos. First, potential faculty adopters have clearly indicated that even with the current minimal monetary cost of installation, the hardware modifications, and time investment remain troublesome factors that scare off interested educators. Second, overcoming the inherent complications that arise due to the shared subnet that result in students\u27 projects interfering with each other in ways that are difficult to recreate, debug, and understand. Specifically, this paper discusses porting the Xinu operating systems to Qemu virtual hardware, developing the virtual networking platform, and results showing success using Virtual Xinu in the classroom during one semester of Operating Systems at the University of Mississippi

StarPlan: A model-based diagnostic system for spacecraft

The Sunnyvale Division of Ford Aerospace created a model-based reasoning capability for diagnosing faults in space systems. The approach employs reasoning about a model of the domain (as it is designed to operate) to explain differences between expected and actual telemetry; i.e., to identify the root cause of the discrepancy (at an appropriate level of detail) and determine necessary corrective action. A development environment, named Paragon, was implemented to support both model-building and reasoning. The major benefit of the model-based approach is the capability for the intelligent system to handle faults that were not anticipated by a human expert. The feasibility of this approach for diagnosing problems in a spacecraft was demonstrated in a prototype system, named StarPlan. Reasoning modules within StarPlan detect anomalous telemetry, establish goals for returning the telemetry to nominal values, and create a command plan for attaining the goals. Before commands are implemented, their effects are simulated to assure convergence toward the goal. After the commands are issued, the telemetry is monitored to assure that the plan is successful. These features of StarPlan, along with associated concerns, issues and future directions, are discussed

Pediatric Developmental Screening: Understanding and Selecting Screening Instruments

Based on a review of research on developmental screening instruments, provides a manual for selecting and applying tools for screening for both general and specific problems. Includes an interactive questionnaire that links to the recommended instrument

Plan variants and a plan refinement algorithm

The relational production model of problem solving, due to Vere, is used to analyze plan inefficiency. The concept of plan variant is introduced and precisely related to the triangle tables of Nilsson. The concept is used to extend certain classes of inefficiencies. A method is described which "tightens up" plans containing these inefficiencies, often producing optimal ones

Dundee Discussion Papers in Economics 214:Longitudinal analysis of income-related health inequality

This paper considers the characterisation and measurement of income-related health inequality using longitudinal data. The paper elucidates the nature of the Jones and Lopez Nicholas (2004) index of “health-related income mobility” and explains the negative values of the index that have been reported in all the empirical applications to date. The paper further questions the value of their index to health policymakers and proposes an alternative index of “income-related health mobility” that measures whether the pattern of health changes is biased in favour of those with initially high or low incomes. We illustrate our work by investigating mobility in the General Health Questionnaire measure of psychological well-being over the first nine waves of the British Household Panel Survey from 1991 to 1999

Escherichia coli O157:H7 in Malta for the first time

The emergence of E coli O157:H7 in Malta is a sign of the times. It represents one of the newly emerging infections associated with food. The first two documented cases of E coli 0157:H7 infection in Malta occurred in July and August, 1996. Food types classically incriminated were surveyed by the Department of Public Health. Epidemiological investigation aimed to trace the environmental sources of infection.• Microbiology was performed jointly by diagnostic and public health laboratories. Facts about infection and control of the disease are highlighted with a view to alerting local practitioners to the condition.peer-reviewe