First, we study hard real-time scheduling problems where each task is defined by a four tuple (r, c, p, d): r being its release time, c computation time, p period, and d deadline. The question is whether all tasks can meet their deadlines on one processor. If not, how many processors are needed? For the one-processor problem, we prove two sufficient conditions for a (restricted) periodic task set to meet deadlines. The two conditions can be applied to both preemptive and non-preemptive scheduling, in sharp contrast to earlier results. If a periodic task set can meet deadlines under any algorithm which does not idle the processor as long as there are tasks ready to execute, it must satisfy our second condition. We also prove a necessary condition for a periodic task set to meet deadlines under any scheduling algorithm. We present a method for transforming a sporadic task to an equivalent periodic task. The transformation method is optimal with respect to non-preemptive scheduling. With this method, all results on scheduling periodic task sets can be applied to sets of both periodic and sporadic tasks. For the scheduling problem in distributed memory systems, we propose various heuristic algorithms which try to use as few processors as possible to meet deadlines. Although our algorithms are non-preemptive, our simulation results show that they can outperform the heuristic algorithms based on the famous preemptive rate monotonic algorithm in terms of the number of used processors and processor utilization rate. Second, we describe a hard real-time software development environment, called HaRTS, which consists of a design tool and a scheduling tool. The design tool supports a hierarchical design diagram which combines the control and data flow of a hard real-time application. The design diagram is quite intuitive, and yet it can be automatically translated into Ada��� code and analyzed for scheduleability. The scheduling tool schedules precedence-constrained periodic task sets and simulates the task execution with highly animated user interfaces, which goes beyond the traditional way of examining a schedule as a static Gantt chart. / Graduation date: 1994

In these studies we evaluated specific environmental stimuli relevant to Salmonella virulence and physiology in the gastrointestinal tract of chickens. Results from Salmonella growth in steady state, glucose-limiting continuous culture (CC) indicated that the optimal growth condition was observed between 0.05 h-1 and 0.27 h-1 dilution rates (D). Cell protein concentrations increased proportionally with an increase in D at each steady state, but after D 0.27 h-1 there was a reduction in the cell protein concentrations as the D increased. Genetic responses generally indicated that the lowest D exhibited highest hilA relative expression. Relatively higher expression of hilA was largely observed at low D (low glucose) (0.0125 h-1, 0.025 h-1, 0.05 h-1). Salmonella incubated in CC at different pH shifts demonstrated that cell protein concentration, glucose utilization, Yield ATP and Acetate:Propionate ratios were influenced by an increase in pH (6.14 to 7.41). These parameters increased and decreased consistently with a corresponding increase and decrease in pH. Polymerase chain reaction-based denaturant gradient gel electrophoresis showed that the overall amplicon band patterns of microbial similarity have demonstrated that hens molted with Alfalfa (ALC+) diet were similar to the Full-Fed (FF+) treatment group. Additional, FF+ and ALC+ treatment groups exhibited a higher percentage similarity coefficient (>90%) than the feed deprived treatment group. Fermentation response from cecal inocula on feed substrates revealed that alfalfa based samples yielded consistently higher short chain fatty acid levels when compared to other feed substrates. Salmonella Enteritidis (SE) colonization in liver, spleen and ovaries was significantly (P < 0.05) higher in FW+ hens compared to ALC+ and FF+ treatments groups. A 4-fold (log10 1.29) reduction in SE colonization for ALC+ hens compared to feed withdrawal hens (FW+) (log10 5.12) SE colonization was observed. Relative expression of hilA in all treatment groups was significantly (P < 0.05) higher in FW+ compared to FF+ and ALC+ groups. hilA expression in FW+ hens was 3.2-, 4.2-, and 1.9-fold higher for Days 6, 11 and 12 respectively, when compared with to ALC+ hens. These results suggest that Salmonella virulence in the gastrointestinal ecology of chickens could be impacted by a combination of low nutrients availability and pH shifts.

In these studies we evaluated specific environmental stimuli relevant to Salmonella virulence and physiology in the gastrointestinal tract of chickens. Results from Salmonella growth in steady state, glucose-limiting continuous culture (CC) indicated that the optimal growth condition was observed between 0.05 h-1 and 0.27 h-1 dilution rates (D). Cell protein concentrations increased proportionally with an increase in D at each steady state, but after D 0.27 h-1 there was a reduction in the cell protein concentrations as the D increased. Genetic responses generally indicated that the lowest D exhibited highest hilA relative expression. Relatively higher expression of hilA was largely observed at low D (low glucose) (0.0125 h-1, 0.025 h-1, 0.05 h-1). Salmonella incubated in CC at different pH shifts demonstrated that cell protein concentration, glucose utilization, Yield ATP and Acetate:Propionate ratios were influenced by an increase in pH (6.14 to 7.41). These parameters increased and decreased consistently with a corresponding increase and decrease in pH. Polymerase chain reaction-based denaturant gradient gel electrophoresis showed that the overall amplicon band patterns of microbial similarity have demonstrated that hens molted with Alfalfa (ALC+) diet were similar to the Full-Fed (FF+) treatment group. Additional, FF+ and ALC+ treatment groups exhibited a higher percentage similarity coefficient (>90%) than the feed deprived treatment group. Fermentation response from cecal inocula on feed substrates revealed that alfalfa based samples yielded consistently higher short chain fatty acid levels when compared to other feed substrates. Salmonella Enteritidis (SE) colonization in liver, spleen and ovaries was significantly (P < 0.05) higher in FW+ hens compared to ALC+ and FF+ treatments groups. A 4-fold (log10 1.29) reduction in SE colonization for ALC+ hens compared to feed withdrawal hens (FW+) (log10 5.12) SE colonization was observed. Relative expression of hilA in all treatment groups was significantly (P < 0.05) higher in FW+ compared to FF+ and ALC+ groups. hilA expression in FW+ hens was 3.2-, 4.2-, and 1.9-fold higher for Days 6, 11 and 12 respectively, when compared with to ALC+ hens. These results suggest that Salmonella virulence in the gastrointestinal ecology of chickens could be impacted by a combination of low nutrients availability and pH shifts.

Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s):Gordon Bradley, Saverio Manago. Includes bibliographical references (p. 87). Also available online.

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Thesis (M.S.S.I.S.)--Regis University, Denver, Colo., 2007. / Title from PDF title page (viewed on Nov. 02, 2007). Includes bibliographical references.

Univ. of Technology, Diss--Eindhoven.