pinecone/core-2020-05-10-deduplication huggingface dataset:
Delegation in predicate encryption supporting disjunctive queries

Predicate encryption has an advantage over traditional public-key or identity-based encryption, since predicate encryption systems provide more flexible control over access to encrypted data. We focus on delegation capabilities in predicate systems. More specifically, we investigate delegatable encryption systems supporting disjunctive predicate evaluations. We present formal security definitions of delegatable predicate encryption and provide the first delegatable predicate encryption scheme which supports disjunctive predicate evaluations in the public-key setting. We analyze the security of the proposed system and give a security proof. In addition, we present a delegatable predicate encryption in the symmetric-key setting and discuss the related security issues
Symbolic-Numeric Algorithms for Computer Analysis of Spheroidal Quantum
  Dot Models

A computation scheme for solving elliptic boundary value problems with
axially symmetric confining potentials using different sets of one-parameter
basis functions is presented. The efficiency of the proposed symbolic-numerical
algorithms implemented in Maple is shown by examples of spheroidal quantum dot
models, for which energy spectra and eigenfunctions versus the spheroid aspect
ratio were calculated within the conventional effective mass approximation.
Critical values of the aspect ratio, at which the discrete spectrum of models
with finite-wall potentials is transformed into a continuous one in strong
dimensional quantization regime, were revealed using the exact and adiabatic
classifications.Comment: 6 figures, Submitted to Proc. of The 12th International Workshop on
  Computer Algebra in Scientific Computing (CASC 2010) Tsakhkadzor, Armenia,
  September 5 - 12, 201
GPGCD, an Iterative Method for Calculating Approximate GCD, for Multiple
  Univariate Polynomials

We present an extension of our GPGCD method, an iterative method for
calculating approximate greatest common divisor (GCD) of univariate
polynomials, to multiple polynomial inputs. For a given pair of polynomials and
a degree, our algorithm finds a pair of polynomials which has a GCD of the
given degree and whose coefficients are perturbed from those in the original
inputs, making the perturbations as small as possible, along with the GCD. In
our GPGCD method, the problem of approximate GCD is transferred to a
constrained minimization problem, then solved with the so-called modified
Newton method, which is a generalization of the gradient-projection method, by
searching the solution iteratively. In this paper, we extend our method to
accept more than two polynomials with the real coefficients as an input.Comment: 12 pages. To appear Proc. CASC 2010 (Computer Algebra in Scientific
  Computing), Tsakhkadzor, Armenia, September 201
Non-clairvoyant Scheduling of Multiple Bag-of-Tasks Applications

International audienceThe bag-of-tasks application model, albeit simple, arises in many application domains and has received a lot of attention in the scheduling literature. Previous works propose either theoretically sound solutions that rely on unrealistic assumptions, or ad-hoc heuristics with no guarantees on performance. This work attempts to bridge this gap through the design of non-clairvoyant heuristics based on solid theoretical foundations. The performance achieved by these heuristics is studied via simulations in a view to comparing them both to previously proposed solutions and to theoretical upper bounds on achievable performance. Also, an interesting theoretical result in this work is that a straightforward on-demand heuristic delivers asymptotically optimal performance when the communications or the computations can be neglected
Starsscheck: a tool to find errors in task-based parallel programs

Star Superscalar is a task-based programming model. The programmer starts with an ordinary C program, and adds pragmas to mark functions as tasks, identifying their inputs and outputs. When the main thread reaches a task, an instance of the task is added to a run-time dependency graph, and later scheduled to run on a processor. Variants of Star Superscalar exist for the Cell Broadband Engine and SMPs.\ud
Star Superscalar relies on the annotations provided by the programmer. If these are incorrect, the program may exhibit race conditions or exceptions deep inside the run-time system.\ud
This paper introduces Starsscheck, a tool based on Valgrind, which helps debug Star Superscalar programs. Starsscheck verifies that the pragma annotations are correct, producing a warning if a task or the main thread performs an invalid access. The tool can be adapted to support similar programming models such as TPC. For most benchmarks, Starsscheck is faster than memcheck, the default Valgrind tool.Postprint (published version
Extending the Cell SPE with Energy Efficient Branch Prediction

Energy-efficient dynamic branch predictors are proposed for the Cell SPE, which normally depends on compiler-inserted hint instructions to predict branches. All designed schemes use a Branch Target Buffer (BTB) to store the branch target address and the prediction, which is computed using a bimodal counter. One prediction scheme pre-decodes instructions when they are fetched from the local store and accesses the BTB only for branch instructions, thereby saving power compared to conventional dynamic predictors that access the BTB for every instruction. In addition, several ways to leverage the existing hint instructions for the dynamic branch predictor are studied. We also introduce branch warning instructions which initiate branch prediction before the actual branch instruction is fetched. They allow fetching the instructions starting at the branch target and thus completely remove the branch penalty for correctly predicted branches. For a 256-entry BTB, a speedup of up to 18.8% is achieved. The power consumption of the branch prediction schemes is estimated at 1% or less of the total power dissipation of the SPE and the average energy-delay product is reduced by up to 6.2%
A formalism for causal explanations with an Answer Set Programming
  translation

We examine the practicality for a user of using Answer Set Programming (ASP)
for representing logical formalisms. Our example is a formalism aiming at
capturing causal explanations from causal information. We show the naturalness
and relative efficiency of this translation job. We are interested in the ease
for writing an ASP program. Limitations of the earlier systems made that in
practice, the ``declarative aspect'' was more theoretical than practical. We
show how recent improvements in working ASP systems facilitate the translation
Developing intelligent environments with OSGi and JADE

Series: IFIP International Federation for Information ProcessingThe development of intelligent environments poses complex
challenges, namely at the level of device heterogeneity and environment
dynamics. In fact, we still lack supporting technologies and development
approaches that can efficiently integrate different devices and technologies. In
this paper we present how a recent integration of two important technologies,
OSGi and Jade, can be used to significantly improve the development process,
making it a more dynamic, modular and configurable one. We also focus on the
main advantages that this integration provides to developers, from the Ambient
Intelligence point of view. This work results from the development of two
intelligent environments: VirtualECare, which is an intelligent environment for
the monitorization of elderly in their homes and UMCourt, a virtual
environment for dispute resolution.The work described in this paper is included in TIARAC -
Telematics and Artificial Intelligence in Alternative Conflict Resolution Project
(PTDC/JUR/71354/2006), which is a research project supported by FCT (Science &
Technology Foundation), Portugal
Multi-GPU and Multi-CPU Parallelization for Interactive Physics Simulations

International audienceToday, it is possible to associate multiple CPUs and multiple GPUs in a single shared memory architecture. Using these resources efficiently in a seamless way is a challenging issue. In this paper, we propose a parallelization scheme for dynamically balancing work load between multiple CPUs and GPUs. Most tasks have a CPU and GPU implementation, so they can be executed on any processing unit. We rely on a two level scheduling associating a traditional task graph partitioning and a work stealing guided by processor affinity and heterogeneity. These criteria are intended to limit inefficient task migrations between GPUs, the cost of memory transfers being high, and to favor mapping small tasks on CPUs and large ones on GPUs to take advantage of heterogeneity. This scheme has been implemented to support the SOFA physics simulation engine. Experiments show that we can reach speedups of 22 with 4 GPUs and 29 with 4 CPU cores and 4 GPUs. CPUs unload GPUs from small tasks making these GPUs more efficient, leading to a "cooperative speedup" greater than the sum of the speedups separatly obtained on 4 GPUs and 4 CPUs
Visual exploration of eye movement data using the Space-Time-Cube

Eye movement recordings produce large quantities of spatio- temporal data, and are more and more frequently used as an aid to gain further insight into human thinking in usability studies in GIScience domain among others. After reviewing some common visualization methods for eye movement data, the limitations of these methods are discussed. This paper proposes an approach that enables the use of the Space-Time-Cube (STC) for representation of eye movement recordings. Via interactive functions in the STC, spatiotemporal patterns in eye movement data could be analyzed. A case study is presented according to proposed solutions for eye movement data analysis. Finally, the advantages and limitations of using the STC to visually analyze eye movement recordings are summarized and discussed
A New Security Model for Authenticated Key Agreement

International audienceThe Canetti–Krawczyk (CK) and extended Canetti–Krawczyk (eCK) security mo-dels, are widely used to provide security arguments for key agreement protocols. We discuss security shades in the (e)CK models, and some practical attacks unconsi-dered in (e)CK–security arguments. We propose a strong security model which en-compasses the eCK one. We also propose a new protocol, called Strengthened MQV (SMQV), which in addition to provide the same efficiency as the (H)MQV protocols, is particularly suited for distributed implementations wherein a tamper–proof device is used to store long–lived keys, while session keys are used on an untrusted host machine. The SMQV protocol meets our security definition under the Gap Diffie– Hellman assumption and the Random Oracle model
Non-deterministic Boolean Proof Nets

16 pagesInternational audienceWe introduce Non-deterministic Boolean proof nets to study the correspondence with Boolean circuits, a parallel model of computation. We extend the cut elimination of Non-deterministic Multiplicative Linear logic to a parallel procedure in proof nets. With the restriction of proof nets to Boolean types, we prove that the cut-elimination procedure corresponds to Non-deterministic Boolean circuit evaluation and reciprocally. We obtain implicit characterization of the complexity classes NP and NC (the efficiently parallelizable functions)
Iridium-catalyzed 1,3-dipolar cycloadditions

1,3-Dipolar cycloaddition reactions (DCR) are atom-economic processes that permit the construction of heterocycles. Their enantioselective versions allow for the creation of up to four adjacent chiral centers in a concerted fashion. In particular, well-defined half-sandwich iridium (III) catalysts have been applied to the DCR between enals or methacrylonitrile with nitrones. Excellent yield and stereoselectivities have been achieved. Support for mechanistic proposals stems from the isolation and characterization of the true catalysts. © 2011 Springer Berlin Heidelberg.The authors thank financial support from Ministerio de Ciencia e Innovación (MICINN, Spain) and FEDER (Grant CTQ2009/10303BQU) and MULTICAT, Consolider Ingenio- 2010 (CSD2009-00050).Peer Reviewe
Rewriting Systems for Reachability in Vector Addition Systems with Pairs

15 pagesInternational audienceWe adapt hypergraph rewriting system to a generalization of Vector Addition Systems with States (VASS) that we call vector addition systems with pairs (VASP). We give rewriting systems and strategies, that allow us to obtain reachability equivalence results between some classes of VASP and VASS. Reachability for the later is well known be equivalent to reachability in Petri nets. VASP generalize also Branching Extension of VASS (BVASS) for which it is unknown if they are more expressive than VASS. We consider here a more restricted notion of reachability for VASP than that for BVASS. However the reachability decision problem corresponding is already equivalent to decidability of the provability in Multiplicative and Exponential Linear Logic (MELL), a question left open for more than 20 years
Credit Risk, Market Sentiment and Randomly-Timed Default

We propose a model for the credit markets in which the random default times
of bonds are assumed to be given as functions of one or more independent
"market factors". Market participants are assumed to have partial information
about each of the market factors, represented by the values of a set of market
factor information processes. The market filtration is taken to be generated
jointly by the various information processes and by the default indicator
processes of the various bonds. The value of a discount bond is obtained by
taking the discounted expectation of the value of the default indicator
function at the maturity of the bond, conditional on the information provided
by the market filtration. Explicit expressions are derived for the bond price
processes and the associated default hazard rates. The latter are not given a
priori as part of the model but rather are deduced and shown to be functions of
the values of the information processes. Thus the "perceived" hazard rates,
based on the available information, determine bond prices, and as perceptions
change so do the prices. In conclusion, explicit expressions are derived for
options on discount bonds, the values of which also fluctuate in line with the
vicissitudes of market sentiment.Comment: To appear in: Stochastic Analysis in 2010, Edited by D. Crisan,
  Springer Verla
A Geometric Approach to the Problem of Unique Decomposition of Processes

This paper proposes a geometric solution to the problem of prime
decomposability of concurrent processes first explored by R. Milner and F.
Moller in [MM93]. Concurrent programs are given a geometric semantics using
cubical areas, for which a unique factorization theorem is proved. An effective
factorization method which is correct and complete with respect to the
geometric semantics is derived from the factorization theorem. This algorithm
is implemented in the static analyzer ALCOOL.Comment: 15 page
Mean-payoff Automaton Expressions

Quantitative languages are an extension of boolean languages that assign to
each word a real number. Mean-payoff automata are finite automata with
numerical weights on transitions that assign to each infinite path the long-run
average of the transition weights. When the mode of branching of the automaton
is deterministic, nondeterministic, or alternating, the corresponding class of
quantitative languages is not robust as it is not closed under the pointwise
operations of max, min, sum, and numerical complement. Nondeterministic and
alternating mean-payoff automata are not decidable either, as the quantitative
generalization of the problems of universality and language inclusion is
undecidable.
  We introduce a new class of quantitative languages, defined by mean-payoff
automaton expressions, which is robust and decidable: it is closed under the
four pointwise operations, and we show that all decision problems are decidable
for this class. Mean-payoff automaton expressions subsume deterministic
mean-payoff automata, and we show that they have expressive power incomparable
to nondeterministic and alternating mean-payoff automata. We also present for
the first time an algorithm to compute distance between two quantitative
languages, and in our case the quantitative languages are given as mean-payoff
automaton expressions
Generalized simulation relations with applications in automata theory

Finite-state automata are a central computational model in computer science, with\ud
numerous and diverse applications. In one such application, viz. model-checking, automata\ud
over infinite words play a central rˆole. In this thesis, we concentrate on B¨uchi automata\ud
(BA), which are arguably the simplest finite-state model recognizing languages\ud
of infinite words. Two algorithmic problems are paramount in the theory of automata:\ud
language inclusion and automata minimization. They are both PSPACE-complete, thus\ud
under standard complexity-theoretic assumptions no deterministic algorithm with worst\ud
case polynomial time can be expected. In this thesis, we develop techniques to tackle\ud
these problems.\ud
In automata minimization, one seeks the smallest automaton recognizing a given\ud
language (“small” means with few states). Despite PSPACE-hardness of minimization,\ud
the size of an automaton can often be reduced substantially by means of quotienting.\ud
In quotienting, states deemed equivalent according to a given equivalence are merged\ud
together; if this merging operation preserves the language, then the equivalence is\ud
said to be Good for Quotienting (GFQ). In general, quotienting cannot achieve exact\ud
minimization, but, in practice, it can still offer a very good reduction in size. The central\ud
topic of this thesis is the design of GFQ equivalences for B¨uchi automata.\ud
A particularly successful approach to the design of GFQ equivalences is based on\ud
simulation relations. Simulation relations are a powerful tool to compare the local\ud
behavior of automata. The main contribution of this thesis is to generalize simulations,\ud
by relaxing locality in three perpendicular ways: by fixing the input word in advance\ud
(fixed-word simulations, Ch. 3), by allowing jumps (jumping simulations, Ch. 4), and by\ud
using multiple pebbles (multipebble simulations for alternating BA, Ch. 5). In each case,\ud
we show that our generalized simulations induce GFQ equivalences. For fixed-word\ud
simulation, we argue that it is the coarsest GFQ simulation implying language inclusion,\ud
by showing that it subsumes a natural hierarchy of GFQ multipebble simulations.\ud
From a theoretical perspective, our study significantly extends the theory of simulations\ud
for BA; relaxing locality is a general principle, and it may find useful applications\ud
outside automata theory. From a practical perspective, we obtain GFQ equivalences\ud
coarser than previously possible. This yields smaller quotient automata, which is beneficial\ud
in applications. Finally, we show how simulation relations have recently been\ud
applied to significantly optimize exact (exponential) language inclusion algorithms\ud
(Ch. 6), thus extending their practical applicability
Completeness of Flat Coalgebraic Fixpoint Logics

Modal fixpoint logics traditionally play a central role in computer science,
in particular in artificial intelligence and concurrency. The mu-calculus and
its relatives are among the most expressive logics of this type. However,
popular fixpoint logics tend to trade expressivity for simplicity and
readability, and in fact often live within the single variable fragment of the
mu-calculus. The family of such flat fixpoint logics includes, e.g., LTL, CTL,
and the logic of common knowledge. Extending this notion to the generic
semantic framework of coalgebraic logic enables covering a wide range of logics
beyond the standard mu-calculus including, e.g., flat fragments of the graded
mu-calculus and the alternating-time mu-calculus (such as alternating-time
temporal logic ATL), as well as probabilistic and monotone fixpoint logics. We
give a generic proof of completeness of the Kozen-Park axiomatization for such
flat coalgebraic fixpoint logics.Comment: Short version appeared in Proc. 21st International Conference on
  Concurrency Theory, CONCUR 2010, Vol. 6269 of Lecture Notes in Computer
  Science, Springer, 2010, pp. 524-53
Information Flow in Interactive Systems

International audienceWe consider the problem of defining the information leakage in interactive systems where secrets and observables can alternate during the computation. We show that the information-theoretic approach which interprets such systems as (simple) noisy channels is not valid anymore. However, the principle can be retrieved if we consider more complicated types of channels, that in Information Theory are known as channels with memory and feedback. We show that there is a complete correspondence between interactive systems and such kind of channels. Furthermore, we show that the capacity of the channels associated to such systems is a continuous function of the Kantorovich metric
Making computer learning easier for older adults: A community study of tuition practices

Older adults are under increasing pressure to use information technologies, yet are reluctant to learn computer software due to difficulties with ways of teaching such skills. This paper argues that examining tutoring techniques in a community computer training centre is useful to discovering why they will persist with learning. Using a Grounded Theory study design, the theory that emerged that accounted for continuance was the tutoring practices and the relationships that were built between tutor and learner. Examples from the data are presented to support the findings that link certain ways of practicing computer tutoring with repeat lesson attendance. This paper contributes to understanding the types of tutoring practices that can encourage older learners to continue the learning journey in later life. In turn, this assists with overcoming the digital divide older learners not skilled in computer use experience and allows them to participate in an increasing technologically driven society
Assessment of Knowledge and Competencies in 3D Virtual Worlds: A Proposal

Proceedings of: Key Competencies in the Knowledge Society World Computer Congress (KCKS 2010). Brisbane, Australia, September 20-23, 2010.Digital natives demand a more active approach to learning. Moreover, the acquisition and assessment of competencies, rather than the mere transmission of information, is becoming more relevant in the Knowledge Society. 3D virtual worlds are a promising environment to meet both of these requirements. In a 3D virtual world, learners are immersed in a rich environment that allows them to have an active experience through their avatars and interaction devices. The learning process in traditional learning management systems has been widely studied, but there is relatively little literature about the use of 3D virtual worlds for learning, although the expectations are high and the possibilities opened immense. This paper focuses on an important part of the teaching and learning process: the assessment. Our aim is to present a set of techniques adapted to this novel 3D medium that allows assessing knowledge, skills, and competencies by using the elements inherent to 3D virtual worlds (avatars, synthetic characters, smart objects) and take advantage of the new dimension introduced.This research is supported by the following projects: The Spanish project “Learn3: Towards Learning of the Third Kind” (TIN2008-05163/TSI) within the Spanish “Plan Nacional de I+D+I”, the Madrid regional project “eMadrid: Investigación y Desarrollo de tecnologías para el e-learning en la Comunidad de Madrid” (S2009/TIC-1650), the European eContentPlus Project “iCoper: Interoperable Content for Performance in a Competency-driven Society” (PPI-2008-A-12).Publicad