2 resultados para NO stripping

em Digital Commons at Florida International University


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Type systems for secure information flow aim to prevent a program from leaking information from H (high) to L (low) variables. Traditionally, bisimulation has been the prevalent technique for proving the soundness of such systems. This work introduces a new proof technique based on stripping and fast simulation, and shows that it can be applied in a number of cases where bisimulation fails. We present a progressive development of this technique over a representative sample of languages including a simple imperative language (core theory), a multiprocessing nondeterministic language, a probabilistic language, and a language with cryptographic primitives. In the core theory we illustrate the key concepts of this technique in a basic setting. A fast low simulation in the context of transition systems is a binary relation where simulating states can match the moves of simulated states while maintaining the equivalence of low variables; stripping is a function that removes high commands from programs. We show that we can prove secure information flow by arguing that the stripping relation is a fast low simulation. We then extend the core theory to an abstract distributed language under a nondeterministic scheduler. Next, we extend to a probabilistic language with a random assignment command; we generalize fast simulation to the setting of discrete time Markov Chains, and prove approximate probabilistic noninterference. Finally, we introduce cryptographic primitives into the probabilistic language and prove computational noninterference, provided that the underling encryption scheme is secure.

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In the article - Past, Present, and Future: The Food Service Industry and Its Changes - by Brother Herman E. Zaccarelli, International Director, Restaurant, Hotel and Institutional Management Institute at Purdue University, Brother Zaccarelli initially states: “Educators play an important role in the evolution of the food service industry. The author discusses that evolution and suggests how educators can be change agents along with management in that evolutionary progression.” The author goes on to wax philosophically, as well as speak generically about the food service industry; to why it offers fascinating and rewarding careers. Additionally, he writes about the influence educators have on students in this regard. “Educators can speak about how the food service industry has benefited them both personally and professionally,” says Brother Zaccarelli. “We get excited about alerting students to the many opportunities and, in fact, serve as “salespersons” for the industry to whoever (school administrators, legislators, and peers in the educational institution) will listen.” Brother Zaccarelli also speaks to growth and changes in food service, and even more importantly about the people and faces behind everything that food service, and hospitality in general comprise. The author will have you know, that people are what drive an educator. “What makes the food service industry so great? At the heart of this question's answer is people: the people whom it serves in institutional and commercial operations of all types; the people who work within it; the people who provide the goods, services, and equipment to it; the people who study it,” says Brother Zaccarelli. “All of these groups have, of course, a vested personal and/or professional interest in seeing our industry improve.” Another concept the author would like you to absorb, and it’s even more so true today than yesterday, is the prevalence of convergence and divergence within food service. For food service and beyond, it is the common denominators and differences that make the hospitality-food service industry so dynamic and vibrant. These are the winds of change presented to an educator who wants to have a positive impact on students. The author warns that the many elements involved in the food service industry conspire to erode quality of service in an industry that is also persistently expanding, and whose cornerstone principles are underpinned by service itself. “The three concerns addressed - quality, employees, and marketing - are intimately related,” Brother Zaccarelli says in stripping-down the industry to bare essentials. He defines and addresses the issues related to each with an eye toward how education can reconcile said issues.