720 research outputs found

    Crypto-Verifying Protocol Implementations in ML

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    We intend to narrow the gap between concrete implementations and verified models of cryptographic protocols. We consider protocols implemented in F#, a variant of ML, and verified using CryptoVerif, Blanchet's protocol verifier for computational cryptography. We experiment with compilers from F# code to CryptoVerif processes, and from CryptoVerif declarations to F# code. We present two case studies: an implementation of the Otway-Rees protocol, and an implementation of a simplified password-based authentication protocol. In both cases, we obtain concrete security guarantees for a computational model closely related to executable code

    Coaching Isn\u27t Just for Little League Anymore: A Theory of Individual Coachability

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    Utilizing coaching as an employee development activity has increased significantly in the practitioner space in recent years. Practitioners have implemented coaching in the modern organization, establishing best practices for both coaches and coachees. Coaching is a dyadic relationship whereby the coach and the coachee play a critical role in the successes obtained by the relationship. Previous academic research in a variety of disciplines, including athletics, entrepreneurship, marketing, and management, has studied the coach/coachee relationship extensively from the perspective of the coach. Although the coach’s perspective is important, practitioners and academics agree that individual coachability is a key individual characteristic of a coachee for coaching success. However, there has been little research evaluating the individual coachee. Further, what little research there is, presents inconsistencies in regards to what makes an individual coachable. Therefore, the purpose of this dissertation is to establish a theory of individual coachability by defining individual coachability and empirically evaluating its elements. Theory development begins with a rigorous literature review. I thoroughly examine current coaching literature, establishing the need for a theory of individual coachability. Through inductive and deductive research, I establish that goal-setting, self-efficacy, feedback, and accountability are important elements of individual coachability. Rooted in the newly developed theory, I define individual coachability for universal use across all areas of research. I achieve this through a series of empirical studies. In Study 1, I develop a measure of coachability, establishing that coachability is a second order construct. I conduct an exploratory factor analysis to confirm the structure. In Study 2, I test the convergent and discriminant validity of the developed scale by comparing it to existing constructs. I conduct a confirmatory factor analysis to establish validity of the constructs in the measurement model. In Study 3, using the established scale from Study 2, I conduct an experiment, using experimental vignette methodology, to observe whether individual coachability influences the relationship between the quality of an organization’s developmental coaching program and various organizational outcomes. More specifically, I hypothesize that the quality of the developmental coaching program and individual coachability will interact to predict job performance, employee engagement, and organizational commitment. I also hypothesize that when a workplace has no developmental coaching program, job performance, employee engagement, and organizational commitment for those high in coachability will be higher than for those who are low in coachability

    Refinement Types for Secure Implementations

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    We present the design and implementation of a typechecker for verifying security properties of the source code of cryptographic protocols and access control mechanisms. The underlying type theory is a λ-calculus equipped with refinement types for expressing pre- and post-conditions within first-order logic. We derive formal cryptographic primitives and represent active adversaries within the type theory. Well-typed programs enjoy assertion-based security properties, with respect to a realistic threat model including key compromise. The implementation amounts to an enhanced typechecker for the general purpose functional language F#; typechecking generates verification conditions that are passed to an SMT solver. We describe a series of checked examples. This is the first tool to verify authentication properties of cryptographic protocols by typechecking their source code. © 2008 IEEE

    Diffraction limited optics for single atom manipulation

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    We present an optical system designed to capture and observe a single neutral atom in an optical dipole trap, created by focussing a laser beam using a large numerical aperture N.A.=0.5 aspheric lens. We experimentally evaluate the performance of the optical system and show that it is diffraction limited over a broad spectral range (~ 200 nm) with a large transverse field (+/- 25 microns). The optical tweezer created at the focal point of the lens is able to trap single atoms of 87Rb and to detect them individually with a large collection efficiency. We measure the oscillation frequency of the atom in the dipole trap, and use this value as an independent determination of the waist of the optical tweezer. Finally, we produce with the same lens two dipole traps separated by 2.2 microns and show that the imaging system can resolve the two atoms.Comment: 8 pages, 9 figures; typos corrected and references adde

    The Visualities and Aesthetics of Prosecuting Aged Defendants

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    This is the author accepted manuscript. The final version is available from Brill via the DOI in this recordThe prosecution—whether domestic or international—of international crimes and atrocities may implicate extremely aged defendants. Much has been written about the legalisms that inhere (or not) in trying these barely alive individuals. Very little however has been written about the aesthetics the barely alive encrust into the architecture of courtrooms, the optics these defendants suffuse into the trial process, and the expressive value of punishing them. This is what we seek to do in this project

    Concurrent constraint programming with process mobility

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    We propose an extension of concurrent constraint programming with primitives for process migration within a hierarchical network, and we study its semantics. To this purpose, we first investigate a "pure " paradigm for process migration, namely a paradigm where the only actions are those dealing with transmissions of processes. Our goal is to give a structural definition of the semantics of migration; namely, we want to describe the behaviour of the system, during the transmission of a process, in terms of the behaviour of the components. We achieve this goal by using a labeled transition system where the effects of sending a process, and requesting a process, are modeled by symmetric rules (similar to handshaking-rules for synchronous communication) between the two partner nodes in the network. Next, we extend our paradigm with the primitives of concurrent constraint programming, and we show how to enrich the semantics to cope with the notions of environment and constraint store. Finally, we show how the operational semantics can be used to define an interpreter for the basic calculus.
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