381 research outputs found

    Artificial Intelligence

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    Contains research objectives and reports on five research projects.Computation Center, M.I.T

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    Improving the Efficiency of Reasoning Through Structure-Based Reformulation

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    Abstract. We investigate the possibility of improving the efficiency of reasoning through structure-based partitioning of logical theories, combined with partitionbased logical reasoning strategies. To this end, we provide algorithms for reasoning with partitions of axioms in first-order and propositional logic. We analyze the computational benefit of our algorithms and detect those parameters of a partitioning that influence the efficiency of computation. These parameters are the number of symbols shared by a pair of partitions, the size of each partition, and the topology of the partitioning. Finally, we provide a greedy algorithm that automatically reformulates a given theory into partitions, exploiting the parameters that influence the efficiency of computation.

    Towards Erlang Verification by Term Rewriting

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    The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-14125-1_7This paper presents a transformational approach to the verification of Erlang programs. We define a stepwise transformation from (first-order) Erlang programs to (non-deterministic) term rewrite systems that compute an overapproximation of the original Erlang program. In this way, existing techniques for term rewriting become available. Furthermore, one can use narrowing as a symbolic execution extension of rewriting in order to design a verification technique. We illustrate our approach with some examples, including a deadlock analysis of a simple Erlang program.Vidal Oriola, GF. (2013). Towards Erlang Verification by Term Rewriting. En Logic-Based Program Synthesis and Transformation. Springer. 109-126. doi:10.1007/978-3-319-14125-1_7S109126Albert, E., Arenas, P., Gómez-Zamalloa, M.: Symbolic Execution of Concurrent Objects in CLP. In: Russo, C., Zhou, N.-F. (eds.) PADL 2012. LNCS, vol. 7149, pp. 123–137. Springer, Heidelberg (2012)Albert, E., Vidal, G.: The narrowing-driven approach to functional logic program specialization. New Generation Computing 20(1), 3–26 (2002)Joe, A., Robert, V., Williams, M.: Concurrent programming in ERLANG. Prentice Hall (1993)Arts, T., Earle, C.B., Derrick, J.: Development of a verified Erlang program for resource locking. STTT 5(2–3), 205–220 (2004)Baader, F., Nipkow, T.: Term Rewriting and All That. Cambridge University Press (1998)Caballero, R., Martin-Martin, E., Riesco, A., Tamarit, S.: A Declarative Debugger for Sequential Erlang Programs. In: Veanes, M., Viganò, L. (eds.) TAP 2013. LNCS, vol. 7942, pp. 96–114. Springer, Heidelberg (2013)Claessen, K., Svensson, H.: A semantics for distributed Erlang. In: Sagonas, K.F., Armstrong, J. (eds.). In: Proc. of the 2005 ACM SIGPLAN Workshop on Erlang, pp. 78–87. ACM (2005)Earle, C.B.: Symbolic program execution using the Erlang verification tool. In: Alpuente, M. (eds.) Proc. of the 9th International Workshop on Functional and Logic Programming (WFLP 2000), pp. 42–55 (2000)Felleisen, M., Friedman, D.P., Kohlbecker, E.E., Duba, B.F.: A syntactic theory of sequential control. Theor. Comput. Sci. 52, 205–237 (1987)Fredlund, L.-A., Svensson, H.: McErlang: a model checker for a distributed functional programming language. In: Hinze, R., Ramsey, N. (eds). In: Proc. of ICFP 2007, pp. 125–136. ACM (2007)Giesl, J., Arts, T.: Verification of Erlang Processes by Dependency Pairs. Appl. Algebra Eng. Commun. Comput. 12(1/2), 39–72 (2001)Hanus, M. (ed.): Curry: An integrated functional logic language (vers. 0.8.3) (2012), http://www.curry-language.orgHuch, F.: Verification of Erlang Programs using Abstract Interpretation and Model Checking. In: Rémi, D., Lee, P. (eds.) Proc. of ICFP 1999, pp. 261–272. ACM (1999)J.-M., H.: Canonical forms and unification. In: Bibel, W., Kowalski, R. (eds.) 5th Conference on Automated Deduction Les Arcs. LNCS, pp. 318–334. Springer, Heidelberg (1980)Leucker, M., Noll, T.: Rewriting Logic as a Framework for Generic Verification Tools. Electr. Notes Theor. Comput. Sci. 36, 121–137 (2000)Meseguer, J.: Conditioned Rewriting Logic as a United Model of Concurrency. Theor. Comput. Sci. 96(1), 73–155 (1992)Neuhäußer, M.R., Noll, T.: Abstraction and Model Checking of Core Erlang Programs in Maude. Electr. Notes Theor. Comput. Sci. 176(4), 147–163 (2007)Nishida, N., Vidal, G.: A finite representation of the narrowing space. In: Proc. of the 23th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2013). Technical Report TR-11-13, Universidad Complutense de Madrid, pp. 113–128 (To appear in Springer LNCS, 2013). http://users.dsic.upv.es/~gvidal/Noll, T.: A Rewriting Logic Implementation of Erlang. Electr. Notes Theor. Comput. Sci. 44(2), 206–224 (2001)Noll, T.: Equational Abstractions for Model Checking Erlang Programs. Electr. Notes Theor. Comput. Sci. 118, 145–162 (2005)Noll, T.G., Fredlund, L., Gurov, D.: The Erlang Verification Tool. In: Margaria, T., Yi, W. (eds.) TACAS 2001. LNCS, vol. 2031, pp. 582–586. Springer, Heidelberg (2001)Roy, C.K.: Thomas Noll, Banani Roy, and James R. Cordy. Towards automatic verification of Erlang programs by pi-calculus translation. In: Feeley,M., Trinder, P.W. (eds.) Proc. of the 2006 ACM SIGPLAN Workshop on Erlang, pp. 38–50. ACM (2006)Slagle, J.R.: Automated theorem-proving for theories with simplifiers, commutativity and associativity. Journal of the ACM 21(4), 622–642 (1974)Svensson, H., Fredlund, L.-A.: A more accurate semantics for distributed Erlang. In: Thompson, S.J., Fredlund. L.-A., (eds.) Proceedings of the 2007 ACM SIGPLAN Workshop on Erlang, pp. 43–54. ACM (2007)Vidal, G.: Closed symbolic execution for verifying program termination. In: Proc. of the 12th IEEE International Working Conference on Source Code Analysis and Manipulation (SCAM 2012), pp. 34–43. IEEE (2012)Visser, W., Havelund, K., Brat, G.P., Park, S., Lerda, F.: Model checking programs. Autom. Softw. Eng. 10(2), 203–232 (2003

    An extension to ALGOL for manipulating formulae

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    Artificial Intelligence

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    Contains research objectives and reports on eight research projects.Computation Center, M.I.T

    Pennsylvania Folklife Vol. 29, No. 3

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    • Shuler Family Correspondence • Vestiges of the Markley Family • 30 Years of the Kutztown Folk Festival: A Photo Essay • The Rural Village • Father of the Fraternity: Christopher Schlegel and Rosicrucianism • A Lexical Comparison of Two Sister Languages: Pennsylvania German and Yiddish • Aldes un Neieshttps://digitalcommons.ursinus.edu/pafolklifemag/1087/thumbnail.jp

    White light thermoplasmonic activated gold nanorod arrays enable the photo-thermal disinfection of medical tools from bacterial contamination

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    The outspread of bacterial pathogens causing severe infections and spreading rapidly, especially among hospitalized patients, is worrying and represents a global public health issue. Current disinfection techniques are becoming insufficient to counteract the spread of these pathogens because they carry multiple antibiotic-resistance genes. For this reason, a constant need exists for new technological solutions that rely on physical methods rather than chemicals. Nanotechnology support provides novel and unexplored opportunities to boost groundbreaking, next-gen solutions. With the help of plasmonic-assisted nanomaterials, we present and discuss our findings in innovative bacterial disinfection techniques. Gold nanorods (AuNRs) immobilized on rigid substrates are utilized as efficient white light-to-heat transducers (thermoplasmonic effect) for photo-thermal (PT) disinfection. The resulting AuNRs array shows a high sensitivity change in refractive index and an extraordinary capability in converting white light to heat, producing a temperature change greater than 50 °C in a few minute interval illumination time. Results were validated using a theoretical approach based on a diffusive heat transfer model. Experiments performed with a strain of Escherichia coli as a model microorganism confirm the excellent capability of the AuNRs array to reduce the bacteria viability upon white light illumination. Conversely, the E. coli cells remain viable without white light illumination, which also confirms the lack of intrinsic toxicity of the AuNRs array. The PT transduction capability of the AuNRs array is utilized to produce white light heating of medical tools used during surgical treatments, generating a temperature increase that can be controlled and is suitable for disinfection. Our findings are pioneering a new opportunity for healthcare facilities since the reported methodology allows non-hazardous disinfection of medical devices by simply employing a conventional white light lamp

    Toward Human-Carnivore Coexistence: Understanding Tolerance for Tigers in Bangladesh

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    Fostering local community tolerance for endangered carnivores, such as tigers (Panthera tigris), is a core component of many conservation strategies. Identification of antecedents of tolerance will facilitate the development of effective tolerance-building conservation action and secure local community support for, and involvement in, conservation initiatives. We use a stated preference approach for measuring tolerance, based on the ‘Wildlife Stakeholder Acceptance Capacity’ concept, to explore villagers’ tolerance levels for tigers in the Bangladesh Sundarbans, an area where, at the time of the research, human-tiger conflict was severe. We apply structural equation modeling to test an a priori defined theoretical model of tolerance and identify the experiential and psychological basis of tolerance in this community. Our results indicate that beliefs about tigers and about the perceived current tiger population trend are predictors of tolerance for tigers. Positive beliefs about tigers and a belief that the tiger population is not currently increasing are both associated with greater stated tolerance for the species. Contrary to commonly-held notions, negative experiences with tigers do not directly affect tolerance levels; instead, their effect is mediated by villagers’ beliefs about tigers and risk perceptions concerning human-tiger conflict incidents. These findings highlight a need to explore and understand the socio-psychological factors that encourage tolerance towards endangered species. Our research also demonstrates the applicability of this approach to tolerance research to a wide range of socio-economic and cultural contexts and reveals its capacity to enhance carnivore conservation efforts worldwide
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