bluuebunny/crossref_metadata_2025 huggingface dataset:
OPTIMAL MIGRATION PROMOTES THE OUTBREAK OF COOPERATION IN HETEROGENEOUS POPULATIONS
Authors: SCHWEITZER FRANK , BEHERA LAXMIDAR
Published: June 2012

We consider a population of agents that are heterogeneous with respect to (i) their strategy when interacting ngtimes with other agents in an iterated prisoners dilemma game, (ii) their spatial location on K different islands. After each generation, agents adopt strategies proportional to their average payoff received. Assuming a mix of two cooperating and two defecting strategies, we first investigate for isolated islands the conditions for an exclusive domination of each of these strategies and their possible coexistence. This allows to define a threshold frequency for cooperation that, dependent on ngand the initial mix of strategies, describes the outbreak of cooperation in the absence of migration. We then allow migration of a fixed fraction of the population after each generation. Assuming a worst case scenario where all islands are occupied by defecting strategies, whereas only one island is occupied by cooperators at the threshold frequency, we determine the optimal migration rate that allows the outbreak of cooperation on all islands. We further find that the threshold frequency divided by the number of islands, i.e., the relative effort for invading defecting islands with cooperators decreases with the number of islands. We also show that there is only a small bandwidth of migration rates, to allow the outbreak of cooperation. Larger migration rates destroy cooperation.
THE CLASS OF NONLINEAR STOCHASTIC MODELS AS A BACKGROUND FOR THE BURSTY BEHAVIOR IN FINANCIAL MARKETS
Authors: GONTIS VYGINTAS , KONONOVICIUS ALEKSEJUS , REIMANN STEFAN
Published: June 2012

We investigate behavior of the continuous stochastic signals above some threshold, bursts, when the exponent of multiplicativity is higher than one. Earlier we have proposed a general nonlinear stochastic model applicable for the modeling of absolute return and trading activity in financial markets which can be transformed into Bessel process with known first hitting (first passage) time statistics. Using these results we derive PDF of burst duration for the proposed model. We confirm derived analytical expressions by numerical evaluation and discuss bursty behavior of return in financial markets in the framework of modeling by nonlinear SDE.
A DOMAIN SPECIFIC LANGUAGE FOR THE DESCRIPTION AND THE SIMULATION OF SYSTEMS OF INTERACTING SYSTEMS
Authors: D'AGOSTINO GREGORIO , DE NICOLA ANTONIO , DI PIETRO ANTONIO , VICOLI GIORDANO , VILLANI MARIA LUISA , ROSATO VITTORIO
Published: June 2012

Systems of technological networks (so-called Critical Infrastructures) might undergo strong perturbations leading to the reduction of their functionalities (crisis scenarios). Under perturbed conditions, infrastructures deliver their specific services in a range from a partial reduction up to a complete loss. Systems of complex technological networks (electrical, telecommunications, roads and railways, oil, gas and water pipelines etc.) are known to display large interdependences (a fault on one system spreads over the others); for this reason, it is relevant to devise simulators and decision support systems able to capture the complexity of such a "system of systems". The paper presents parts of the outcomes of a larger scientific project aiming at realizing a Decision Support System to predict the occurrence of undesired events and their consequences. In particular, we present a conceptual modeling approach consisting of a declarative language and a software implementation for the description and simulation of elements of Crisis Scenarios. The software application is conceived for risk managers, i.e. operators with a deep knowledge of critical infrastructure scenarios, but not necessarily with high-level IT or mathematical skill.
NONEXTENSIVE STATISTICAL MECHANICS DISTRIBUTIONS AND DYNAMICS OF FINANCIAL OBSERVABLES FROM THE NONLINEAR STOCHASTIC DIFFERENTIAL EQUATIONS
Authors: RUSECKAS JULIUS , GONTIS VYGINTAS , KAULAKYS BRONISLOVAS
Published: June 2012

We present nonlinear stochastic differential equations, generating processes with the q-exponential and q-Gaussian distributions of the observables, i.e. with the long-range power-law autocorrelations and 1/fβpower spectral density. Similarly, the Tsallis q-distributions may be obtained in the superstatistical framework as a superposition of different local dynamics at different time intervals. In such approach, the average of the stochastic variable is generated by the nonlinear stochastic process, while the local distribution of the signal is exponential or Gaussian one, conditioned by the slow average. Further we analyze relevance of the generalized and adapted equations for modeling the financial processes. We model the inter-trade durations, the trading activity and the normalized return using the superstatistical approaches with the exponential and normal distributions of the local signals driven by the nonlinear stochastic process.
meso-Tetraphenylporphyrin-derived oxypyriporphyrin, oxypyrichlorin, and thiomorpholinochlorin, as their Ni(II) complexes
Authors: Banerjee Subhadeep , Zeller Matthias , Brückner Christian
Published: June 2012

trans-Diolchlorin was prepared by nucleophilic addition of methyl-Grignard bromide to meso-tetraphenyl-2,3-dioxoporphyrin, as its free base or Ni(II) complex. The trans-configuration of the vic-diol functionality was shown by single crystal X-ray diffractometry. The nickel complex of the trans-dimethyldiol proved susceptible to Pb(IV) acetate-induced, oxidative diol cleavage, generating a meso-tetraphenylsecochlorin bismethylketone Ni(II) complex, the first example of this chromophore class. Under Brønsted-basic conditions, this bisketone cyclized via an intramolecular aldol condensation to provide a meso-tetraphenyloxypyriporphyrin. Reduction of this porphyrin analog saturated the double bond in the pyridinone moiety, generating an oxypyrichlorin. Reaction of the meso-tetraphenylsecochlorin bismethylketone Ni(II) complex with Lawesson's reagent induced the formation of a thiomorpholinochlorin substituted with two methylene groups, the first example of any porphyrin analog containing a thiomorpholine moiety.
Open System Approach to the Internal Dynamics of a Model Multilevel Molecule
Authors: Giraldi F. , Petruccione F.
Published: June 2012

A model multilevel molecule described by two sets of rotational internal energy levels of different parity and degenerate ground states, coupled by a constant interaction, is considered, by assuming that the random collisions in a gas of identical molecules, provoke transitions between adjacent energy levels of the same parity. The prescriptions of the continuous time quantum random walk is applied to the single molecule, interpreted as an open quantum system, and the master equation driving its internal dynamics is built for a general distribution of random collision times. Over estimated long time scales, the dynamics of the coherence terms and the populations of the energy levels is evaluated analytically for relevant classes of non-Poissonian distributions of the collision times. Inverse power law relaxations and the inverse Zeno effect emerge over estimated long time scales and the stable asymptotic equilibrium configuration results to be independent of the distribution of the collision times.
Entanglement of Open Quantum Systems in Noninertial Frames
Authors: Khan S. , Khan M. K.
Published: June 2012

We study the effects of decoherence on the entanglement generated by Unruh effect in accelerated frames by using various combinations of an amplitude damping channel, a phase damping channel and a depolarizing channel in the form of multilocal and collective environments. Using concurrence as entanglement quantifier, we show that the occurrence of entanglement sudden death (ESD) depends on different combinations of the channels. The ESD can be avoided under a particular configuration of the channels. We show that the channels can be used to distinguish between a moving and a stationary frame.
Modified Hodgkin-Huxley Equations Arising from Mesoscopic Voltage-Gated Processes
Authors: Tejo A. Mauricio
Published: June 2012

The voltage-gated ion channels system is an example of a classical open system. This work establishes conditions on open ion channel dynamics for which a modified Hodgkin-Huxley equation for the membrane voltage arises as propagation of chaos. This is the approach we propose in order to study the mesoscopic voltage-gated ion channel dynamics together with the macroscopic voltage equation.
Entropy of a Flow on Non-compact Sets
Authors: Shen Jinghua , Zhao Yun
Published: June 2012

Based on the theory of Carathéodory structure, this paper introduces the topological entropy of a flow on non-compact sets. Moreover, we introduce the definition of measure-theoretic entropy of a flow. It is shown that this entropy is equivalent to the one defined by Sun in [10]. The variational principle between topological entropy and measure-theoretic entropy of a flow is established. We also get the Brin-Katok's entropy formula for a flow.
Introduction to the Transactions on Interactive Intelligent Systems
Authors: Jameson Anthony , Riedl John
Published: June 2012

This editorial introduction describes the aims and scope of the
ACM Transactions on Interactive Intelligent Systems
, explains how it aims to constitute a landmark addition to the publication landscape, and shows how the five articles in this inaugural issue fit into the journal's conception.
Why-oriented end-user debugging of naive Bayes text classification
Authors: Kulesza Todd , Stumpf Simone , Wong Weng-Keen , Burnett Margaret M. , Perona Stephen , Ko Amy J. , Oberst Ian
Published: June 2012

Machine learning techniques are increasingly used in
intelligent assistants
, that is, software targeted at and continuously adapting to assist end users with email, shopping, and other tasks. Examples include desktop SPAM filters, recommender systems, and handwriting recognition. Fixing such intelligent assistants when they learn incorrect behavior, however, has received only limited attention. To directly support end-user “debugging” of assistant behaviors learned via statistical machine learning, we present a Why-oriented approach which allows users to ask questions about how the assistant made its predictions, provides answers to these “why” questions, and allows users to interactively
change
these answers to debug the assistant's current and future predictions. To understand the strengths and weaknesses of this approach, we then conducted an exploratory study to investigate barriers that participants could encounter when debugging an intelligent assistant using our approach, and the information those participants requested to overcome these barriers. To help ensure the inclusiveness of our approach, we also explored how gender differences played a role in understanding barriers and information needs. We then used these results to consider opportunities for Why-oriented approaches to address user barriers and information needs.
Active multiple kernel learning for interactive 3D object retrieval systems
Authors: Hoi Steven C. H. , Jin Rong
Published: June 2012

An effective relevance feedback solution plays a key role in interactive intelligent 3D object retrieval systems. In this work, we investigate the relevance feedback problem for interactive intelligent 3D object retrieval, with the focus on studying effective machine learning algorithms for improving the user's interaction in the retrieval task. One of the key challenges is to learn appropriate kernel similarity measure between 3D objects through the relevance feedback interaction with users. We address this challenge by presenting a novel framework of
Active multiple kernel learning
(AMKL), which exploits multiple kernel learning techniques for relevance feedback in interactive 3D object retrieval. The proposed framework aims to efficiently identify an optimal combination of multiple kernels by asking the users to label the most informative 3D images. We evaluate the proposed techniques on a dataset of over 10,000 3D models collected from the World Wide Web. Our experimental results show that the proposed AMKL technique is significantly more effective for 3D object retrieval than the regular relevance feedback techniques widely used in interactive content-based image retrieval, and thus is promising for enhancing user's interaction in such interactive intelligent retrieval systems.
Introduction to the special issue on eye gaze in intelligent human-machine interaction
Authors: André Elisabeth , Chai Joyce Y.
Published: June 2012

Given the recent advances in eye tracking technology and the availability of nonintrusive and high-performance eye tracking devices, there has never been a better time to explore new opportunities to incorporate eye gaze in intelligent and natural human-machine communication. In this special issue, we present six articles that cover various aspects of eye gaze in human-machine interaction, including applications of gaze tracking in human-machine interaction, techniques that recognize gaze gestures and render gaze behaviors, and the analysis of gaze behaviors in social interactions.
Conversational gaze mechanisms for humanlike robots
Authors: Mutlu Bilge , Kanda Takayuki , Forlizzi Jodi , Hodgins Jessica , Ishiguro Hiroshi
Published: June 2012

During conversations, speakers employ a number of verbal and nonverbal mechanisms to establish who participates in the conversation, when, and in what capacity. Gaze cues and mechanisms are particularly instrumental in establishing the participant roles of interlocutors, managing speaker turns, and signaling discourse structure. If humanlike robots are to have fluent conversations with people, they will need to use these gaze mechanisms effectively. The current work investigates people's use of key conversational gaze mechanisms, how they might be designed for and implemented in humanlike robots, and whether these signals effectively shape human-robot conversations. We focus particularly on whether humanlike gaze mechanisms might help robots signal different participant roles, manage turn-exchanges, and shape how interlocutors perceive the robot and the conversation. The evaluation of these mechanisms involved 36 trials of three-party human-robot conversations. In these trials, the robot used gaze mechanisms to signal to its conversational partners their roles either of two addressees, an addressee and a bystander, or an addressee and a nonparticipant. Results showed that participants conformed to these intended roles 97% of the time. Their conversational roles affected their rapport with the robot, feelings of groupness with their conversational partners, and attention to the task.
Adaptive eye gaze patterns in interactions with human and artificial agents
Authors: Yu Chen , Schermerhorn Paul , Scheutz Matthias
Published: June 2012

Efficient collaborations between interacting agents, be they humans, virtual or embodied agents, require mutual recognition of the goal, appropriate sequencing and coordination of each agent's behavior with others, and making predictions from and about the likely behavior of others. Moment-by-moment eye gaze plays an important role in such interaction and collaboration. In light of this, we used a novel experimental paradigm to systematically investigate gaze patterns in both human-human and human-agent interactions. Participants in the study were asked to interact with either another human or an embodied agent in a joint attention task. Fine-grained multimodal behavioral data were recorded including eye movement data, speech, first-person view video, which were then analyzed to discover various behavioral patterns. Those patterns show that human participants are highly sensitive to momentary multimodal behaviors generated by the social partner (either another human or an artificial agent) and they rapidly adapt their gaze behaviors accordingly. Our results from this data-driven approach provide new findings for understanding micro-behaviors in human-human communication which will be critical for the design of artificial agents that can generate human-like gaze behaviors and engage in multimodal interactions with humans.
Emotional body language displayed by artificial agents
Authors: Beck Aryel , Stevens Brett , Bard Kim A. , Cañamero Lola
Published: June 2012

Complex and natural social interaction between artificial agents (computer-generated or robotic) and humans necessitates the display of rich emotions in order to be believable, socially relevant, and accepted, and to generate the natural emotional responses that humans show in the context of social interaction, such as engagement or empathy. Whereas some robots use faces to display (simplified) emotional expressions, for other robots such as Nao, body language is the best medium available given their inability to convey facial expressions. Displaying emotional body language that can be interpreted whilst interacting with the robot should significantly improve naturalness. This research investigates the creation of an affect space for the generation of emotional body language to be displayed by humanoid robots. To do so, three experiments investigating how emotional body language displayed by agents is interpreted were conducted. The first experiment compared the interpretation of emotional body language displayed by humans and agents. The results showed that emotional body language displayed by an agent or a human is interpreted in a similar way in terms of recognition. Following these results, emotional key poses were extracted from an actor's performances and implemented in a Nao robot. The interpretation of these key poses was validated in a second study where it was found that participants were better than chance at interpreting the key poses displayed. Finally, an affect space was generated by blending key poses and validated in a third study. Overall, these experiments confirmed that body language is an appropriate medium for robots to display emotions and suggest that an affect space for body expressions can be used to improve the expressiveness of humanoid robots.
Eliciting caregiving behavior in dyadic human-robot attachment-like interactions
Authors: Hiolle Antoine , Cañamero Lola , Davila-Ross Marina , Bard Kim A.
Published: June 2012

We present here the design and applications of an arousal-based model controlling the behavior of a Sony AIBO robot during the exploration of a novel environment: a children's play mat. When the robot experiences too many new perceptions, the increase of arousal triggers calls for attention towards its human caregiver. The caregiver can choose to either calm the robot down by providing it with comfort, or to leave the robot coping with the situation on its own. When the arousal of the robot has decreased, the robot moves on to further explore the play mat. We gathered results from two experiments using this arousal-driven control architecture. In the first setting, we show that such a robotic architecture allows the human caregiver to influence greatly the learning outcomes of the exploration episode, with some similarities to a primary caregiver during early childhood. In a second experiment, we tested how human adults behaved in a similar setup with two different robots: one “needy”, often demanding attention, and one more independent, requesting far less care or assistance. Our results show that human adults recognise each profile of the robot for what they have been designed, and behave accordingly to what would be expected, caring more for the needy robot than for the other. Additionally, the subjects exhibited a preference and more positive affect whilst interacting and rating the robot we designed as needy. This experiment leads us to the conclusion that our architecture and setup succeeded in eliciting positive and caregiving behavior from adults of different age groups and technological background. Finally, the consistency and reactivity of the robot during this dyadic interaction appeared crucial for the enjoyment and engagement of the human partner.
Spotting laughter in natural multiparty conversations
Authors: Scherer Stefan , Glodek Michael , Schwenker Friedhelm , Campbell Nick , Palm Günther
Published: June 2012

It is essential for the advancement of human-centered multimodal interfaces to be able to infer the current user's state or communication state. In order to enable a system to do that, the recognition and interpretation of multimodal social signals (i.e., paralinguistic and nonverbal behavior) in real-time applications is required. Since we believe that laughs are one of the most important and widely understood social nonverbal signals indicating affect and discourse quality, we focus in this work on the detection of laughter in natural multiparty discourses. The conversations are recorded in a natural environment without any specific constraint on the discourses using unobtrusive recording devices. This setup ensures natural and unbiased behavior, which is one of the main foci of this work. To compare results of methods, namely Gaussian Mixture Model (GMM) supervectors as input to a Support Vector Machine (SVM), so-called Echo State Networks (ESN), and a Hidden Markov Model (HMM) approach, are utilized in online and offline detection experiments. The SVM approach proves very accurate in the offline classification task, but is outperformed by the ESN and HMM approach in the online detection (F
1
scores: GMM SVM 0.45, ESN 0.63, HMM 0.72). Further, we were able to utilize the proposed HMM approach in a cross-corpus experiment without any retraining with respectable generalization capability (F
1
score: 0.49). The results and possible reasons for these outcomes are shown and discussed in the article. The proposed methods may be directly utilized in practical tasks such as the labeling or the online detection of laughter in conversational data and affect-aware applications.
Affect recognition based on physiological changes during the watching of music videos
Authors: Yazdani Ashkan , Lee Jong-Seok , Vesin Jean-Marc , Ebrahimi Touradj
Published: June 2012

Assessing emotional states of users evoked during their multimedia consumption has received a great deal of attention with recent advances in multimedia content distribution technologies and increasing interest in personalized content delivery. Physiological signals such as the electroencephalogram (EEG) and peripheral physiological signals have been less considered for emotion recognition in comparison to other modalities such as facial expression and speech, although they have a potential interest as alternative or supplementary channels. This article presents our work on: (1) constructing a dataset containing EEG and peripheral physiological signals acquired during presentation of music video clips, which is made publicly available, and (2) conducting binary classification of induced positive/negative valence, high/low arousal, and like/dislike by using the aforementioned signals. The procedure for the dataset acquisition, including stimuli selection, signal acquisition, self-assessment, and signal processing is described in detail. Especially, we propose a novel asymmetry index based on relative wavelet entropy for measuring the asymmetry in the energy distribution of EEG signals, which is used for EEG feature extraction. Then, the classification systems based on EEG and peripheral physiological signals are presented. Single-trial and single-run classification results indicate that, on average, the performance of the EEG-based classification outperforms that of the peripheral physiological signals. However, the peripheral physiological signals can be considered as a good alternative to EEG signals in the case of assessing a user's preference for a given music video clip (like/dislike) since they have a comparable performance to EEG signals while being more easily measured.
Integrating trust management and access control in data-intensive Web applications
Authors: Vimercati Sabrina De Capitani Di , Foresti Sara , Jajodia Sushil , Paraboschi Stefano , Psaila Giuseppe , Samarati Pierangela
Published: June 2012

The widespread diffusion of Web-based services provided by public and private organizations emphasizes the need for a flexible solution for protecting the information accessible through Web applications. A promising approach is represented by credential-based access control and trust management. However, although much research has been done and several proposals exist, a clear obstacle to the realization of their benefits in data-intensive Web applications is represented by the lack of adequate support in the DBMSs. As a matter of fact, DBMSs are often responsible for the management of most of the information that is accessed using a Web browser or a Web service invocation.

In this article, we aim at eliminating this gap, and present an approach integrating trust management with the access control of the DBMS. We propose a trust model with a SQL syntax and illustrate an algorithm for the efficient verification of a delegation path for certificates. Our solution nicely complements current trust management proposals allowing the efficient realization of the services of an advanced trust management model within current relational DBMSs. An important benefit of our approach lies in its potential for a robust end-to-end design of security for personal data in Web scenario, where vulnerabilities of Web applications cannot be used to violate the protection of the data residing on the database server. We also illustrate the implementation of our approach within an open-source DBMS discussing design choices and performance impact.
Modellus
Authors: Desnoyers Peter , Wood Timothy , Shenoy Prashant , Singh Rahul , Patil Sangameshwar , Vin Harrick
Published: June 2012

The rising complexity of distributed server applications in Internet data centers has made the tasks of modeling and analyzing their behavior increasingly difficult. This article presents
Modellus
, a novel system for automated modeling of complex web-based data center applications using methods from queuing theory, data mining, and machine learning. Modellus uses queuing theory and statistical methods to automatically derive models to predict the resource usage of an application and the workload it triggers; these models can be composed to capture multiple dependencies between interacting applications.

Model accuracy is maintained by fast, distributed testing, automated relearning of models when they change, and methods to bound prediction errors in composite models. We have implemented a prototype of Modellus, deployed it on a data center testbed, and evaluated its efficacy for modeling and analysis of several distributed multitier web applications. Our results show that this feature-based modeling technique is able to make predictions across several data center tiers, and maintain predictive accuracy (typically 95% or better) in the face of significant shifts in workload composition; we also demonstrate practical applications of the Modellus system to prediction and provisioning of real-world data center applications.
Cardinal directions between complex regions
Authors: Schneider Markus , Chen Tao , Viswanathan Ganesh , Yuan Wenjie
Published: June 2012

Besides topological relationships and approximate relationships,
cardinal directions
like
north
and
southwest
have turned out to be an important class of qualitative spatial relationships. They are of interdisciplinary interest in fields like cognitive science, robotics, artificial intelligence, and qualitative spatial reasoning. In spatial databases and Geographic Information Systems (GIS) they are frequently used as join and selection criteria in spatial queries. However, the available computational models of cardinal directions suffer a number of problems like the use of too coarse approximations of the two spatial operand objects in terms of single representative points or minimum bounding rectangles, the lacking property of converseness of the cardinal directions computed, and the limited applicability to
simple
instead of
complex
regions only. This article proposes and formally defines a novel two-phase model, called the
Objects Interaction Matrix
(OIM) model, that solves these problems, and determines cardinal directions for even complex regions. The model consists of a tiling phase and an interpretation phase. In the
tiling phase
, a tiling strategy first determines the zones belonging to the nine cardinal directions of each individual region object and then intersects them. The result leads to a bounded grid called
objects interaction grid
. For each grid cell the information about the region objects that intersect it is stored in an
objects interaction matrix
. In the subsequent
interpretation phase
, a well-defined interpretation method is applied to such a matrix and determines the cardinal direction. Spatial example queries illustrate our new cardinal direction concept that is embedded in a spatial extension of SQL and provides user-defined cardinal direction predicates.
Certain conjunctive query answering in first-order logic
Authors: Wijsen Jef
Published: June 2012

Primary key violations provide a natural means for modeling uncertainty in the relational data model. A repair (or possible world) of a database is then obtained by selecting a maximal number of tuples without ever selecting two distinct tuples that have the same primary key value. For a Boolean query
q
, the problem CERTAINTY(
q
) takes as input a database
db
and asks whether
q
evaluates to true on every repair of
db
. We are interested in determining queries
q
for which CERTAINTY(
q
) is first-order expressible (and hence in the low complexity class
AC
°). For queries
q
in the class of conjunctive queries without self-join, we provide a necessary syntactic condition for first-order expressibility of CERTAINTY(
q
). For acyclic queries (in the sense of Beeri et al. [1983]), this necessary condition is also a sufficient condition. So we obtain a decision procedure for first-order expressibility of CERTAINTY(
q
) when
q
is acyclic and without self-join. We also show that if CERTAINTY(
q
) is first-order expressible, its first-order definition, commonly called certain first-order rewriting, can be constructed in a rather straightforward way.
Comparing workflow specification languages
Authors: Abiteboul Serge , Bourhis Pierre , Vianu Victor
Published: June 2012

We address the problem of comparing the expressiveness of workflow specification formalisms using a notion of
view
of a workflow. Views allow to compare widely different workflow systems by mapping them to a common representation capturing the observables relevant to the comparison. Using this framework, we compare the expressiveness of several workflow specification mechanisms, including automata, temporal constraints, and pre-and postconditions, with XML and relational databases as underlying data models. One surprising result shows the considerable power of static constraints to simulate apparently much richer workflow control mechanisms.
Secure distributed computation of anonymized views of shared databases
Authors: Tassa Tamir , Gudes Ehud
Published: June 2012

We consider the problem of computing efficient anonymizations of partitioned databases. Given a database that is partitioned between several sites, either horizontally or vertically, we devise secure distributed algorithms that allow the different sites to obtain a
k
-anonymized and ℓ-diverse view of the union of their databases, without disclosing sensitive information. Our algorithms are based on the sequential algorithm [Goldberger and Tassa 2010] that offers anonymizations with utility that is significantly better than other anonymization algorithms, and in particular those that were implemented so far in the distributed setting. Our algorithms can apply to different generalization techniques and utility measures and to any number of sites. While previous distributed algorithms depend on costly cryptographic primitives, the cryptographic assumptions of our solution are surprisingly minimal.
The implication problem of data dependencies over SQL table definitions
Authors: Hartmann Sven , Link Sebastian
Published: June 2012

We investigate the implication problem for classes of data dependencies over SQL table definitions. Under Zaniolo's “no information” interpretation of null markers we establish an axiomatization and algorithms to decide the implication problem for the combined class of functional and multivalued dependencies in the presence of NOT NULL constraints. The resulting theory subsumes three previously orthogonal frameworks. We further show that the implication problem of this class is equivalent to that in a propositional fragment of Schaerf and Cadoli's [1995] family of para-consistent S-3 logics. In particular, S is the set of variables that correspond to attributes declared NOT NULL. We also show how our equivalences for multivalued dependencies can be extended to Delobel's class of full first-order hierarchical decompositions, and the equivalences for functional dependencies can be extended to arbitrary Boolean dependencies. These dualities allow us to transfer several findings from the propositional fragments to the corresponding classes of data dependencies, and vice versa. We show that our results also apply to Codd's null interpretation “value unknown at present”, but not to Imielinski's [1989] or-relations utilizing Levene and Loizou's weak possible world semantics [Levene and Loizou 1998]. Our findings establish NOT NULL constraints as an effective mechanism to balance not only the certainty in database relations but also the expressiveness with the efficiency of entailment relations. They also control the degree by which the implication of data dependencies over total relations is soundly approximated in SQL table definitions.
Axiom based architecture
Authors: Mueller Conrad
Published: June 2012

The paper proposes an axiom based architecture as an alternative to the von Neumann model. The model has many desirable properties: fine-grained parallelism, simple semantics, better security and easy of programming. The empirical research gives some indication of its performance potential.

A description is given as to how algebraic arithmetic expressions of relations can be broken up into primitive expressions consisting of a single operation. These primitive relations are shown to be sufficient to describe a Turing machine. Eight inference rules are given that define how the primitive relations can be evaluated. An outline is given of an architecture based on these inference rules. Finally a brief description is given of an experimental emulation and empirical evaluation of the architecture.

Instead of manipulating data or values by applying instructions or functions, computation is applying existing elements to relations to create new elements. The element's identifier determines which relations the element applies to. The relation determines the identifier of the new element and the operation that needs to be applied to create the value of the new element.

The conceptually indices are different in this model. Instead of seeing an index as an offset into an array, an index is seen as part of the element identifier. This enables infinitely many relations to be defined between unique sets using universal quantifiers. Thus every element, or value, computed has a unique description.
FPGA implementation of a novel architecture for performance enhancement of Radix-2 FFT
Authors: Giri Nishant Kumar , Sinha Amitabha
Published: June 2012

This paper presents a novel architecture for the enhancement of performance of compute intensive Fast Fourier Transform (FFT) algorithm which is common in many signal processing applications. The proposed architecture exhibits faster response time compared to radix-2 'Single-path Delay Feedback (SDF)' architecture and 'radix-2 Multi-path Delay Commutator (MDC)' architecture. The architecture was simulated using Modelsim and was implemented on Xilinx Virtex 4 FPGA.
A new architecture for FPGA implementation of a MAC unit for digital signal processors using mixed number system
Authors: Ghosh Aniruddha , Singha Satrughna , Sinha Amitabha
Published: June 2012

Execution of arithmetic operations at very high speed in real time is the major concern in digital signal processing (DSP) because DSP algorithms are computation intensive. In recent times, Residue Number Systems (RNS) are considered as alternative to binary number system because of their capabilities of performing "carry-free" addition and Multiplication. Double Base Number Systems (DBNS), another non-binary number systems are also increasingly becoming attractive for signal processing applications due to their capabilities of handling arithmetic operations, particularly multiplication efficiently. However, the complexity involved in converting binary to DBNS becomes a major bottleneck and the efficiency of performance decreases considerably due to large conversion time. So RNS Adder and DBNS Multiplier can be used to implement multiply & accumulate (MAC) units. Because RNS adders are less complex and faster compared to DBNS and DBNS multipliers are efficient compared to RNS multiplier. MAC units are the key units in Digital Signal Processors. In this paper we have shown how FIR filter can be implemented using the proposed "Mixed Number System MAC units".
"Floating point RNS"
Authors: Ghosh Aniruddha , Singha Satrughna , Sinha Amitabha
Published: June 2012

Execution of arithmetic operations at a very high speed in real time is the major concern in compute intensive digital signal processing (DSP) algorithms Residue Number Systems are being considered as alternative to binary number system because of their capabilities of performing "carry free" arithmetic operations. However, RNS systems have so far been used to handle integer numbers only. Floating Point RNS arithmetic units have obvious advantages over fixed point multiply & accumulate (MAC) units which are the key units in Digital Signal Processors. Keeping this in view, in this paper, the architecture of a floating point MAC unit is presented.
(Keynote Lecture) Multi-Metal Nano-Electrocatalysts Based on Carbon Nitride
Supports for the ORR and FOR in PEM Fuel Cells
Authors: Di Noto Vito , Negro Enrico , Giffin Guinevere A.
Published: June 2012

New multi-metal nano-electrocatalysts based on carbon nitride supports provide a viable
strategy to overcome the drawbacks of the current state-of-the-art systems used to promote
the oxygen reduction reaction (ORR) and the fuel oxidation reaction (FOR) in PEM fuel
cells. These new materials are prepared by decomposing in an inert atmosphere a homogenous
precursor obtained by coordinating the desired metal centers with a suitable organic
binder. A systematic investigation of electrocatalysts with different metal and nitrogen
concentrations combined with an examination of the effect of the preparation parameters
result in a framework that can be used to optimize the performance of this family of
electrocatalysts. The best results are obtained from systems with a "core-shell"
morphology, where an active carbon core supports a shell of multi-metal carbon nitrides
with a low nitrogen concentration. Promising results are also obtained in the FOR for
methanol and ethanol oxidation processes in acidic conditions.
(Keynote Lecture) The Thermodynamic and Practical Limits to Energy Conversion: Considerations in the Search for Alternative Energy Sources
Authors: Vanýsek Petr
Published: June 2012

This paper discusses efficiency of energy production based on the various methods used to generate it. The purpose of the paper is to point out the need of inclusion of the energy cost associated in obtaining all the materials (not just the fuel) needed to produce energy. The discussion starts with thermodynamic efficiency and them moves to the energy costs associated with mining, refining, construction and manufacturing of the construction materials. The concept of embodied energy, i.e., energy used to create the product (or the energetic material, for that matter) is explained and given for certain products or systems. Among the several options to classical (fossil) fuel reserves, solar energy conversion as a resource is considered.
NMR Measurement of Gel Electrolytes during Polymerization Process
Authors: Korinek Radim , Bartusek Karel , Vondrák Jiri
Published: June 2012

The article deal with NMR measurement and evaluation of relaxation times T1, T2 and diffusion of gel electrolytes based on the NaClO4 inorganic salt during UV polymerization process. Properties and behaviors of gel electrolytes during this process are defined by measured quantities. The measurement is focused on 23Na and 1H nuclei. To measure T1, T2 and diffusion the basic NMR methods were used. The relaxation times of NaClO4 mixed with propylene carbonate (PC) is found to be T1a = 39.2 ms and T1b = 1.5 ms. The approximation, we used two-exponential function and the calculation itself was carried out using a genetic algorithm (GA).
NMR Investigation of Li+ Ion Interactions in Some Precursors of the Lithium Polymer Battery System
Authors: Abbrent Nováková Sabina , Kříž Jaroslav , Michálek Jiří
Published: June 2012

High resolution NMR has been used to reveal interactions between components in prepared electrolyte material prior to polymerization that was aimed for use in lithium polymer battery research. Previous results indicated a decrease in lithium mobility with increased amount of methoxysilyl groups contained in the sample. 1H, 13C, 7Li, and 29Si NMR spectra as well as pulsed field-gradient (PFG NMR) measurements of the self-diffusion of lithium ions were obtained and a preferred coordination of lithium ions to the methoxysilyl groups was proved. Although this interaction seems quite weak, based on the small shifts observed in the spectra, a clear decrease in lithium diffusion dependent on the increased content of methoxysilyl groups was shown.
Physical Properties of Sulfolane - Dimethylcarbonate Mixture for Using in Electrolytes for Lithium-Ion Batteries
Authors: Máca Josef , Sedlaříková Marie , Vondrák Jiří , Bartušek Karel
Published: June 2012

The aim of this work is to determine the melting point for different ratio of solvents. The solvent used for lowering flammability - sulfolane, have a high melting point 27.5°C. Sulfolane would greatly limit the range of temperatures where it can be used. That's why we need to add a second solvent, with modifies the mixture properties for becoming a batter use in lithio - ion batteries. As a second solvent was selected dimethylcarbonate, which is non-toxic and environmentally friendly.
(Keynote Lecture) The Research on Lithium-Ion Batteries for Electric Cars in the Universidad Nacional de La Plata
Authors: Visintin Arnaldo , Thomas Jorge E. , Becker M. Daniela , Castro B. , Milocco Ruben , Real Silvia , Sacco Juan , Garaventta Guillermo N. , Triaca Walter E.
Published: June 2012

The great challenge of our times is to replace polluting oil energy sources with renewable and clean energies that are ready to be used, which requires addressing the need for proper storage solutions. Electric energy storage should be clean, economical, efficient, safe, have long useful life and high specific capacity (mass and volume). The lithium-ion batteries fulfill most of these requirements. To expand the scope of application of these batteries, which are currently used in electric cars, we are working on the development of techniques to construct electrodes with a good response to high discharge currents. Results on the development of lithium iron phosphates with olivine structures to be used as cathodes in advanced batteries are presented.
Cobalt Doped LiFePO4/C Composite Material for Li-Ion Cathodes
Authors: Čech Ondrej , Thomas Jorge E. , Visintin Arnaldo , Sedlarikova Marie , Vondrák Jiri , Moreno Sergio
Published: June 2012

High temperature solid state synthesis was used for preparation of LiFePO4/C composite material and cobalt doped LiFePO4/C composite material. Glycine assisted combustion method was involved as a carbon coating procedure. It uses glycine as a carbon precursor for conductive coating and connecting of active material nanoparticles. Two different samples were prepared and investigated - clear LiFePO4/C material and LiFePO4/C doped with 1% of cobalt. The aim of this work is to show how a supervalent ion of cobalt influences parameters of cathode material. Electrochemical characterization by galvanostatic cycling, electrochemical impedance spectroscopy and rate capability was made and physical characterization by SEM, TEM and X-ray diffraction was provided.
Negative Electrode of Lithium Secondary Cells
Authors: Makovička Jaromír , Libich Jiří , Sedlaříková Marie , Vondrák Jiří
Published: June 2012

This study deals with solving the problem of negative carbon materials for lithium-ion accumulators. The main aim is to obtain good familiarity of carbonaceous materials and propose possible improvements in the parameters related to the negative electrode accumulators. Carbonaceous materials are used as a substitute for metal lithium uses for secondary cells, where uses their intercalation ability. Lithium has a great specific capacity 3860 Ah.g-1, but Lithium has many properties unsuitable for using in accumulators as low number of cycles, high price, volatility. Carbonaceous materials have the required properties with the exception of specific capacity around 350 mAh.g-1, increase of specific capacity is among other things the object of this study.
Incorporation of Multielement Doping into LDH Structure of Alpha Nickel Hydroxide
Authors: Maca Tomas , Vondrák Jiri , Sedlaříková Marie
Published: June 2012

Reffered-to work was aimed at clarifying of the reasons for its transformation tendency with the aim of finding a proper inhibition method. Based on our former experience with an individual-element's doping, simultaneous incorporation of the selected elements into brucite type lattice of nickel hydroxide appears to be suitable solution for fulfilment of the purpose.
Electrocatalytic Properties of Nanocomposites for Electrochemical Power Sources from the Standpoint of Localization of Reactions
Authors: Danilov Michail O. , Kolbasov Genady Y. , Rusetskii Igor A. , Slobodyanyuk Ivan A.
Published: June 2012

Nanocomposites of carbon nanotubes with deposited catalysts have been obtained, which were investigated in oxygen electrodes. The coefficients α of Tafel equation for molecular oxygen evolution at these catalysts have been determined. A dependence of oxygen electrode characteristics on the value of the coefficient α for oxygen evolution reaction has been discovered. This phenomenon has been explained in terms of localization of electrochemical reactions at the catalyst and support, and the assumption has been made that the catalytic properties of materials can be predicted.
Improving the Negative Lead-Acid Battery Electrodes by Using Extra Additives
Authors: Křivík Petr , Bača Petr , Tonar Karel , Tošer Pavel
Published: June 2012

In this project, the aim is to investigate the mechanism of action of carbon in negative electrodes of VRLA cells operating under hybrid vehicle (HEV) duty in the partial state of charge (PSoC) regime. This will contribute to the efforts to increase their specific energy and cycle life, and to elucidation of the causes of their premature capacity loss (PCL3).
Concentrator Photovoltaic Systems
Authors: Vesely Ales , Vanek Jiri , Stojan Radek
Published: June 2012

This paper deals with experimental concentrator photovoltaic system build in cooperation with Solartec s.r.o. company. The system is used to test hypotheses and study the behavior during its operation. The aim is to measure concentration ratio, temperature and electrical characteristics and to compare advantages of active and passive cooling of photovoltaic cells.