OpenRaiser/Intern-Atlas huggingface dataset:
Testing Differences Statistically with the Leiden Ranking
Venue: arXiv cs.CY 2011
Year: 2011

The Leiden Ranking 2011/2012 provides the Proportion top-10% publications (PP top 10%) as a new indicator. This indicator allows for testing the difference between two ranks for statistical significance.
Iterative Deterministic Equivalents for the Performance Analysis of Communication Systems
Venue: arXiv cs.IT 2011
Year: 2011

In this article, we introduce iterative deterministic equivalents as a novel technique for the performance analysis of communication systems whose channels are modeled by complex combinations of independent random matrices. This technique extends the deterministic equivalent approach for the study of functionals of large random matrices to a broader class of random matrix models which naturally arise as channel models in wireless communications. We present two specific applications: First, we consider a multi-hop amplify-and-forward (AF) MIMO relay channel with noise at each stage and derive deterministic approximations of the mutual information after the Kth hop. Second, we study a MIMO multiple access channel (MAC) where the channel between each transmitter and the receiver is represented by the double-scattering channel model. We provide deterministic approximations of the mutual information, the signal-to-interference-plus-noise ratio (SINR) and sum-rate with minimum-mean-square-error (MMSE) detection and derive the asymptotically optimal precoding matrices. In both scenarios, the approximations can be computed by simple and provably converging fixed-point algorithms and are shown to be almost surely tight in the limit when the number of antennas at each node grows infinitely large. Simulations suggest that the approximations are accurate for realistic system dimensions. The technique of iterative deterministic equivalents can be easily extended to other channel models of interest and is, therefore, also a new contribution to the field of random matrix theory.
On Bounding Problems of Quantitative Information Flow
Venue: arXiv cs.CR 2011
Year: 2011

Researchers have proposed formal definitions of quantitative information flow based on information theoretic notions such as the Shannon entropy, the min entropy, the guessing entropy, belief, and channel capacity. This paper investigates the hardness of precisely checking the quantitative information flow of a program according to such definitions. More precisely, we study the "bounding problem" of quantitative information flow, defined as follows: Given a program M and a positive real number q, decide if the quantitative information flow of M is less than or equal to q. We prove that the bounding problem is not a k-safety property for any k (even when q is fixed, for the Shannon-entropy-based definition with the uniform distribution), and therefore is not amenable to the self-composition technique that has been successfully applied to checking non-interference. We also prove complexity theoretic hardness results for the case when the program is restricted to loop-free boolean programs. Specifically, we show that the problem is PP-hard for all definitions, showing a gap with non-interference which is coNP-complete for the same class of programs. The paper also compares the results with the recently proved results on the comparison problems of quantitative information flow.
Online Learning for Classification of Low-rank Representation Features and Its Applications in Audio Segment Classification
Venue: arXiv cs.LG 2011
Year: 2011

In this paper, a novel framework based on trace norm minimization for audio segment is proposed. In this framework, both the feature extraction and classification are obtained by solving corresponding convex optimization problem with trace norm regularization. For feature extraction, robust principle component analysis (robust PCA) via minimization a combination of the nuclear norm and the $\ell_1$-norm is used to extract low-rank features which are robust to white noise and gross corruption for audio segments. These low-rank features are fed to a linear classifier where the weight and bias are learned by solving similar trace norm constrained problems. For this classifier, most methods find the weight and bias in batch-mode learning, which makes them inefficient for large-scale problems. In this paper, we propose an online framework using accelerated proximal gradient method. This framework has a main advantage in memory cost. In addition, as a result of the regularization formulation of matrix classification, the Lipschitz constant was given explicitly, and hence the step size estimation of general proximal gradient method was omitted in our approach. Experiments on real data sets for laugh/non-laugh and applause/non-applause classification indicate that this novel framework is effective and noise robust.
Simple and Robust Binary Self-Location Patterns
Venue: arXiv cs.IT 2011
Year: 2011

A simple method to generate a two-dimensional binary grid pattern, which allows for absolute and accurate self-location in a finite planar region, is proposed. The pattern encodes position information in a local way so that reading a small number of its black or white pixels at any place provides sufficient data from which the location can be decoded both efficiently and robustly.
Development of Grid e-Infrastructure in South-Eastern Europe
Venue: arXiv cs.DC 2011
Year: 2011

Over the period of 6 years and three phases, the SEE-GRID programme has established a strong regional human network in the area of distributed scientific computing and has set up a powerful regional Grid infrastructure. It attracted a number of user communities and applications from diverse fields from countries throughout the South-Eastern Europe. From the infrastructure point view, the first project phase has established a pilot Grid infrastructure with more than 20 resource centers in 11 countries. During the subsequent two phases of the project, the infrastructure has grown to currently 55 resource centers with more than 6600 CPUs and 750 TBs of disk storage, distributed in 16 participating countries. Inclusion of new resource centers to the existing infrastructure, as well as a support to new user communities, has demanded setup of regionally distributed core services, development of new monitoring and operational tools, and close collaboration of all partner institution in managing such a complex infrastructure. In this paper we give an overview of the development and current status of SEE-GRID regional infrastructure and describe its transition to the NGI-based Grid model in EGI, with the strong SEE regional collaboration.
A Multipath Transport Protocol for Future Internet
Venue: arXiv cs.NI 2011
Year: 2011

A Multipath Transport Protocol for Future Internet
Cluster Analysis for a Scale-Free Folksodriven Structure Network
Venue: arXiv cs.SI 2011
Year: 2011

Folksonomy is said to provide a democratic tagging system that reflects the opinions of the general public, but it is not a classification system and it is hard to make sense of. It would be necessary to share a representation of contexts by all the users to develop a social and collaborative matching. The solution could be to help the users to choose proper tags thanks to a dynamical driven system of folksonomy that could evolve during the time. This paper uses a cluster analysis to measure a new concept of a structure called "Folksodriven", which consists of tags, source and time. Many approaches include in their goals the use of folksonomy that could evolve during time to evaluate characteristics. This paper describes an alternative where the goal is to develop a weighted network of tags where link strengths are based on the frequencies of tag co-occurrence, and studied the weight distributions and connectivity correlations among nodes in this network. The paper proposes and analyzes the network structure of the Folksodriven tags thought as folksonomy tags suggestions for the user on a dataset built on chosen websites. It is observed that the hypergraphs of the Folksodriven are highly connected and that the relative path lengths are relatively low, facilitating thus the serendipitous discovery of interesting contents for the users. Then its characteristics, Clustering Coefficient, is compared with random networks. The goal of this paper is a useful analysis of the use of folksonomies on some well known and extensive web sites with real user involvement. The advantages of the new tagging method using folksonomy are on a new interesting method to be employed by a knowledge management system. *** This paper has been accepted to the International Conference on Social Computing and its Applications (SCA 2011) - Sydney Australia, 12-14 December 2011 ***
Complexity and Algorithms for Euler Characteristic of Simplicial Complexes
Venue: arXiv cs.CG 2011
Year: 2011

We consider the problem of computing the Euler characteristic of an abstract simplicial complex given by its vertices and facets. We show that this problem is #P-complete and present two new practical algorithms for computing Euler characteristic. The two new algorithms are derived using combinatorial commutative algebra and we also give a second description of them that requires no algebra. We present experiments showing that the two new algorithms can be implemented to be faster than previous Euler characteristic implementations by a large margin.
TEMANEJO - a debugger for task based parallel programming models
Venue: arXiv cs.DC 2011
Year: 2011

We present the program Temanejo, a debugger for task based parallelisation models such as StarSs. The challenge in debugging StarSs applications lies in the fact that tasks are scheduled at runtime, i.e dynamically in accordance to the data dependencies between them. Our tool assists the programmer in the debugging process by visualising the task dependency graph and allowing to control the scheduling of tasks. The toolset consists of the library Ayudame which communicates with the StarSs runtime on one side and of the debugger Temanejo on the other side which communicates with Ayudame. Temanejo provides a graphical user interface with which the application can be analysed and controlled.
Passive and Driven Trends in the Evolution of Complexity
Venue: arXiv cs.NE 2011
Year: 2011

The nature and source of evolutionary trends in complexity is difficult to assess from the fossil record, and the driven vs. passive nature of such trends has been debated for decades. There are also questions about how effectively artificial life software can evolve increasing levels of complexity. We extend our previous work demonstrating an evolutionary increase in an information theoretic measure of neural complexity in an artificial life system (Polyworld), and introduce a new technique for distinguishing driven from passive trends in complexity. Our experiments show that evolution can and does select for complexity increases in a driven fashion, in some circumstances, but under other conditions it can also select for complexity stability. It is suggested that the evolution of complexity is entirely driven---just not in a single direction---at the scale of species. This leaves open the question of evolutionary trends at larger scales.
Relativistic causality and clockless circuits
Venue: arXiv cs.DC 2011
Year: 2011

Time plays a crucial role in the performance of computing systems. The accurate modelling of logical devices, and of their physical implementations, requires an appropriate representation of time and of all properties that depend on this notion. The need for a proper model, particularly acute in the design of clockless delay-insensitive (DI) circuits, leads one to reconsider the classical descriptions of time and of the resulting order and causal relations satisfied by logical operations. This questioning meets the criticisms of classical spacetime formulated by Einstein when founding relativity theory and is answered by relativistic conceptions of time and causality. Applying this approach to clockless circuits and considering the trace formalism, we rewrite Udding's rules which characterize communications between DI components. We exhibit their intrinsic relation with relativistic causality. For that purpose, we introduce relativistic generalizations of traces, called R-traces, which provide a pertinent description of communications and compositions of DI components.
One-Bit Quantizers for Fading Channels
Venue: arXiv cs.IT 2011
Year: 2011

We study channel capacity when a one-bit quantizer is employed at the output of the discrete-time average-power-limited Rayleigh-fading channel. We focus on the low signal-to-noise ratio regime, where communication at very low spectral efficiencies takes place, as in Spread Spectrum and Ultra-Wideband communications. We demonstrate that, in this regime, the best one-bit quantizer does not reduce the asymptotic capacity of the coherent channel, but it does reduce that of the noncoherent channel.
Enhancing Support for Knowledge Works: A relatively unexplored vista of computing research
Venue: arXiv cs.AI 2011
Year: 2011

Let us envision a new class of IT systems, the "Support Systems for Knowledge Works" or SSKW. An SSKW can be defined as a system built for providing comprehensive support to human knowledge-workers while performing instances of complex knowledge-works of a particular type within a particular domain of professional activities To get an idea what an SSKW-enabled work environment can be like, let us look into a hypothetical scenario that depicts the interaction between a physician and a patient-care SSKW during the activity of diagnosing a patient.
Detecting Threat E-mails using Bayesian Approach
Venue: arXiv cs.CR 2011
Year: 2011

Fraud and terrorism have a close connect in terms of the processes that enables and promote them. In the era of Internet, its various services that include Web, e-mail, social networks, blogs, instant messaging, chats, etc. are used in terrorism not only for communication but also for i) creation of ideology, ii) resource gathering, iii) recruitment, indoctrination and training, iv) creation of terror network, and v) information gathering. A major challenge for law enforcement and intelligence agencies is efficient and accurate gathering of relevant and growing volume of crime data. This paper reports on use of established Naïve Bayesian filter for classification of threat e-mails. Efficiency in filtering threat e-mail by use of three different Naïve Bayesian filter approaches i.e. single keywords, weighted multiple keywords and weighted multiple keywords with keyword context matching are evaluated on a threat e-mail corpus created by extracting data from sources that are very close to terrorism.
Partially Symmetric Functions are Efficiently Isomorphism-Testable
Venue: arXiv cs.DS 2011
Year: 2011

Given a function f: {0,1}^n \to {0,1}, the f-isomorphism testing problem requires a randomized algorithm to distinguish functions that are identical to f up to relabeling of the input variables from functions that are far from being so. An important open question in property testing is to determine for which functions f we can test f-isomorphism with a constant number of queries. Despite much recent attention to this question, essentially only two classes of functions were known to be efficiently isomorphism testable: symmetric functions and juntas. We unify and extend these results by showing that all partially symmetric functions---functions invariant to the reordering of all but a constant number of their variables---are efficiently isomorphism-testable. This class of functions, first introduced by Shannon, includes symmetric functions, juntas, and many other functions as well. We conjecture that these functions are essentially the only functions efficiently isomorphism-testable. To prove our main result, we also show that partial symmetry is efficiently testable. In turn, to prove this result we had to revisit the junta testing problem. We provide a new proof of correctness of the nearly-optimal junta tester. Our new proof replaces the Fourier machinery of the original proof with a purely combinatorial argument that exploits the connection between sets of variables with low influence and intersecting families. Another important ingredient in our proofs is a new notion of symmetric influence. We use this measure of influence to prove that partial symmetry is efficiently testable and also to construct an efficient sample extractor for partially symmetric functions. We then combine the sample extractor with the testing-by-implicit-learning approach to complete the proof that partially symmetric functions are efficiently isomorphism-testable.
Security Survey of Internet Browsers Data Managers
Venue: arXiv cs.CR 2011
Year: 2011

The paper analyses current versions of top three used Internet browsers and compare their security levels to a research done in 2006. The security is measured by analyzing how user data is stored. Data recorded during different browsing sessions and by different password management functions it is considered sensitive data. The paper describes how the browser protects the sensitive data and how an attacker or a forensic analyst can access it.
Dynamic Composition of Evolving Process Types
Venue: arXiv cs.SE 2011
Year: 2011

Classical approaches like process algebras or labelled transition systems deal with static composition to model non-trivial concurrent or distributed systems; this is not sufficient for systems with dynamic architecture and with variable number of components. We introduce a method to guide the modelling and the dynamic composition of processes to build large distributed systems with dynamic adhoc architecture. The modelling and the composition are based on an event-based approach that favour the decoupling of the system components. The composition uses the sharing of abstract communication channels. The method is appropriate to deal with evolving processes (with mobility, mutation). The event-B method is used for practical support. A fauna and its evolution are considered as a working system; this system presents some specificities, its behaviour is not foreseeable, it has an adhoc (not statically fixed) architecture.
The Tutte-Grothendieck group of a convergent alphabetic rewriting system
Venue: arXiv cs.DM 2011
Year: 2011

The two operations, deletion and contraction of an edge, on multigraphs directly lead to the Tutte polynomial which satisfies a universal problem. As observed by Brylawski in terms of order relations, these operations may be interpreted as a particular instance of a general theory which involves universal invariants like the Tutte polynomial, and a universal group, called the Tutte-Grothendieck group. In this contribution, Brylawski's theory is extended in two ways: first of all, the order relation is replaced by a string rewriting system, and secondly, commutativity by partial commutations (that permits a kind of interpolation between non commutativity and full commutativity). This allows us to clarify the relations between the semigroup subject to rewriting and the Tutte-Grothendieck group: the later is actually the Grothendieck group completion of the former, up to the free adjunction of a unit (this was even not mention by Brylawski), and normal forms may be seen as universal invariants. Moreover we prove that such universal constructions are also possible in case of a non convergent rewriting system, outside the scope of Brylawski's work.
Descriptor learning for omnidirectional image matching
Venue: arXiv cs.CV 2011
Year: 2011

Feature matching in omnidirectional vision systems is a challenging problem, mainly because complicated optical systems make the theoretical modelling of invariance and construction of invariant feature descriptors hard or even impossible. In this paper, we propose learning invariant descriptors using a training set of similar and dissimilar descriptor pairs. We use the similarity-preserving hashing framework, in which we are trying to map the descriptor data to the Hamming space preserving the descriptor similarity on the training set. A neural network is used to solve the underlying optimization problem. Our approach outperforms not only straightforward descriptor matching, but also state-of-the-art similarity-preserving hashing methods.
Block local elimination algorithms for solving sparse discrete optimization problems
Venue: arXiv cs.DM 2011
Year: 2011

Block elimination algorithms for solving sparse discrete optimization problems are considered. The numerical example is provided. The benchmarking is done in order to define real computational capabilities of block elimination algorithms combined with SYMPHONY solver. Analysis of the results show that for sufficiently large number of blocks and small enough size of separators between the blocks for staircase integer linear programming problem the local elimination algorithms in combination with a solver for solving subproblems in blocks allow to solve such problems much faster than used solver itself for solving the whole problem. Also the capabilities of postoptimal analysis (warm starting) are considered for solving packages of integer linear programming problems for corresponding blocks.
On the Impact of Energy Dissipation Model on Characteristic Distance in Wireless Networks
Venue: arXiv cs.IT 2011
Year: 2011

In this paper we investigate the dependency of characteristic distance on energy dissipation model. Both the many-to-one and any-to-any communication paradigm have been presented for performance analysis. Characteristic distance has been derived for three different cases. This study will be useful for designing an energy-efficient wireless network where nodes are energy-constrained.
On Multiple Round Sponsored Search Auctions with Budgets
Venue: arXiv cs.GT 2011
Year: 2011

In a sponsored search auction the advertisement slots on a search result page are generally ordered by click-through rate. Bidders have a valuation, which is usually assumed to be linear in the click-through rate, a budget constraint, and receive at most one slot per search result page (round). We study multi-round sponsored search auctions, where the different rounds are linked through the budget constraints of the bidders and the valuation of a bidder for all rounds is the sum of the valuations for the individual rounds. All mechanisms published so far either study one-round sponsored search auctions or the setting where every round has only one slot and all slots have the same click-through rate, which is identical to a multi-item auction. This paper contains the following three results: (1) We give the first mechanism for the multi-round sponsored search problem where different slots have different click-through rates. Our mechanism is incentive compatible in expectation, individually rational in expectation, Pareto optimal in expectation, and also ex-post Pareto optimal for each realized outcome. (2) Additionally we study the combinatorial setting, where each bidder is only interested in a subset of the rounds. We give a deterministic, incentive compatible, individually rational, and Pareto optimal mechanism for the setting where all slots have the same click-through rate. (3) We present an impossibility result for auctions where bidders have diminishing marginal valuations. Specifically, we show that even for the multi-unit (one slot per round) setting there is no incentive compatible, individually rational, and Pareto optimal mechanism for private diminishing marginal valuations and public budgets.