OpenRaiser/Intern-Atlas huggingface dataset:
Chip and Skim: cloning EMV cards with the pre-play attack
Venue: arXiv cs.CY 2012
Year: 2012

EMV, also known as "Chip and PIN", is the leading system for card payments worldwide. It is used throughout Europe and much of Asia, and is starting to be introduced in North America too. Payment cards contain a chip so they can execute an authentication protocol. This protocol requires point-of-sale (POS) terminals or ATMs to generate a nonce, called the unpredictable number, for each transaction to ensure it is fresh. We have discovered that some EMV implementers have merely used counters, timestamps or home-grown algorithms to supply this number. This exposes them to a "pre-play" attack which is indistinguishable from card cloning from the standpoint of the logs available to the card-issuing bank, and can be carried out even if it is impossible to clone a card physically (in the sense of extracting the key material and loading it into another card). Card cloning is the very type of fraud that EMV was supposed to prevent. We describe how we detected the vulnerability, a survey methodology we developed to chart the scope of the weakness, evidence from ATM and terminal experiments in the field, and our implementation of proof-of-concept attacks. We found flaws in widely-used ATMs from the largest manufacturers. We can now explain at least some of the increasing number of frauds in which victims are refused refunds by banks which claim that EMV cards cannot be cloned and that a customer involved in a dispute must therefore be mistaken or complicit. Pre-play attacks may also be carried out by malware in an ATM or POS terminal, or by a man-in-the-middle between the terminal and the acquirer. We explore the design and implementation mistakes that enabled the flaw to evade detection until now: shortcomings of the EMV specification, of the EMV kernel certification process, of implementation testing, formal analysis, or monitoring customer complaints. Finally we discuss countermeasures.
Sociotechnical Management Model for Governance of an Ecosystem
Venue: arXiv cs.OH 2012
Year: 2012

This is an opinion paper regarding a proposal of a model for a Ecosystemm Governance. In the globalized world the importance of Information Systems (IS) and Information Technology (IT) become increasingly relevant regarding the requirements imposed by competition. Both the knowledge of the business as the rapid flow of information are fundamental for a enterprise decision making. Whereas the basic definition of IT = hardware + software, i.e., tools that has been used to create, store and disseminate data and information in the creation of knowledge, and IS = IT + People + procedures that collect, process and disseminate the information to support decision making, coordination, control, analysis and visualization in the organization [01], it makes implicit the understanding of IS is essential to create competitive companies, to manage global corporations and provide customers with products and services of value. In this work we are correlating IS with the governance of management of an ecosystem. Yet, as IT is redefining the foundations of business, then the customer service, operations, strategies of product marketing and its distribution and even the knowledge management (KM) depends very much, or sometimes even completely, on the IS. The IT and its costs have become a part of day-to-day business [02]. In order to meet this complexity of business needs, today is not possible to disregard the IT and its available resources, which makes very dificult to draw up IS. Therefore, the perspective view of the Sociotehcnical Aspects of an IS are directly concerned with governance and the model proposed regarding an ecosystem. Finally, whereas the summary above, the main objective of this opinion paper is to propose the guidelines for a Sociotechnical Management Model of Governance for an Ecosystem.
Review of strategies for a comprehensive simulation in sputtering devices
Venue: arXiv cs.CE 2012
Year: 2012

The development of sputtering facilities, at the moment, is mainly pursued through experimental tests, or simply by expertise in the field, and relies much less on numerical simulation of the process environment. This leads to great efforts and empirically, roughly optimized solutions: in fact, the simulation of these devices, at the state of art, is quite good in predicting the behavior of single steps of the overall deposition process, but it seems still ahead a full integration among the tools simulating the various phenomena involved in a sputter. We summarize here the techniques and codes already available for problems of interest in sputtering facilities, and we try to outline the possible features of a comprehensive simulation framework. This framework should be able to integrate the single paradigms, dealing with aspects going from the plasma environment up to the distribution and properties of the deposited film, not only on the surface of the substrate, but also on the walls of the process chamber.
New Crosstalk Avoidance Codes Based on a Novel Pattern Classification
Venue: arXiv cs.IT 2012
Year: 2012

The crosstalk delay associated with global on-chip interconnects becomes more severe in deep submicron technology, and hence can greatly affect the overall system performance. Based on a delay model proposed by Sotiriadis et al., transition patterns over a bus can be classified according to their delays. Using this classification, crosstalk avoidance codes (CACs) have been proposed to alleviate the crosstalk delays by restricting the transition patterns on a bus. In this paper, we first propose a new classification of transition patterns, and then devise a new family of CACs based on this classification. In comparison to the previous classification, our classification has more classes and the delays of its classes do not overlap, both leading to more accurate control of delays. Our new family of CACs includes some previously proposed codes as well as new codes with reduced delays and improved throughput. Thus, this new family of crosstalk avoidance codes provides a wider variety of tradeoffs between bus delay and efficiency. Finally, since our analytical approach to the classification and CACs treats the technology-dependent parameters as variables, our approach can be easily adapted to a wide variety of technology.
Conditional validity of inductive conformal predictors
Venue: arXiv cs.LG 2012
Year: 2012

Conformal predictors are set predictors that are automatically valid in the sense of having coverage probability equal to or exceeding a given confidence level. Inductive conformal predictors are a computationally efficient version of conformal predictors satisfying the same property of validity. However, inductive conformal predictors have been only known to control unconditional coverage probability. This paper explores various versions of conditional validity and various ways to achieve them using inductive conformal predictors and their modifications.
Simplifying Contract-Violating Traces
Venue: arXiv cs.SE 2012
Year: 2012

Contract conformance is hard to determine statically, prior to the deployment of large pieces of software. A scalable alternative is to monitor for contract violations post-deployment: once a violation is detected, the trace characterising the offending execution is analysed to pinpoint the source of the offence. A major drawback with this technique is that, often, contract violations take time to surface, resulting in long traces that are hard to analyse. This paper proposes a methodology together with an accompanying tool for simplifying traces and assisting contract-violation debugging.
Molecular Communication Between Two Populations of Bacteria
Venue: arXiv cs.IT 2012
Year: 2012

Molecular communication is an expanding body of research. Recent advances in biology have encouraged using genetically engineered bacteria as the main component in the molecular communication. This has stimulated a new line of research that attempts to study molecular communication among bacteria from an information-theoretic point of view. Due to high randomness in the individual behavior of the bacterium, reliable communication between two bacteria is almost impossible. Therefore, we recently proposed that a population of bacteria in a cluster is considered as a node capable of molecular transmission and reception. This proposition enables us to form a reliable node out of many unreliable bacteria. The bacteria inside a node sense the environment and respond accordingly. In this paper, we study the communication between two nodes, one acting as the transmitter and the other as the receiver. We consider the case in which the information is encoded in the concentration of molecules by the transmitter. The molecules produced by the bacteria in the transmitter node propagate in the environment via the diffusion process. Then, their concentration sensed by the bacteria in the receiver node would decode the information. The randomness in the communication is caused by both the error in the molecular production at the transmitter and the reception of molecules at the receiver. We study the theoretical limits of the information transfer rate in such a setup versus the number of bacteria per node. Finally, we consider M-ary modulation schemes and study the achievable rates and their error probabilities.
Comparison Study for Clonal Selection Algorithm and Genetic Algorithm
Venue: arXiv cs.NE 2012
Year: 2012

Two metaheuristic algorithms namely Artificial Immune Systems (AIS) and Genetic Algorithms are classified as computational systems inspired by theoretical immunology and genetics mechanisms. In this work we examine the comparative performances of two algorithms. A special selection algorithm, Clonal Selection Algorithm (CLONALG), which is a subset of Artificial Immune Systems, and Genetic Algorithms are tested with certain benchmark functions. It is shown that depending on type of a function Clonal Selection Algorithm and Genetic Algorithm have better performance over each other.
Simulating Performance of a BitTorrent-Based P2P TV System
Venue: arXiv cs.NI 2012
Year: 2012

In this paper we describe a prototype of a simulation framework and some ideas which are to be used to study performance of a P2P TV system in a controllable and adjustable environment. We created a simplified model describing live video distribution in a P2P TV system. Using the model we analyse how some of the system parameters influence its behaviour. We present the preliminary results obtained at different granularity levels of measurements, describing the macroscopic system performance as well as the performance of its individual components.
A Robust Cryptographic System using Neighborhood-Generated Keys
Venue: arXiv cs.CR 2012
Year: 2012

The ability to hide information from unauthorized individuals has been a prevalent issue over the years. Countless algorithms such as DES, AES and SHA have been developed. These algorithms depend on varying key length and key management strategies to encrypt and decrypt messages. The size of the encrypted message is so large that it therefore consumes and wastes valuable storage space when implemented in organizations that store and handle large volumes of small data. The ability to share the generated keys securely also poses a problem. This paper proposes a robust cryptographic algorithm which generates its keys from the surroundings and already-designed coding schemes. The proposed system conserves storage space and processing power.The algorithm is implemented and tested using PHP and MySQL DBMS.
Relaxing the Gaussian AVC
Venue: arXiv cs.IT 2012
Year: 2012

The arbitrarily varying channel (AVC) is a conservative way of modeling an unknown interference, and the corresponding capacity results are pessimistic. We reconsider the Gaussian AVC by relaxing the classical model and thereby weakening the adversarial nature of the interference. We examine three different relaxations. First, we show how a very small amount of common randomness between transmitter and receiver is sufficient to achieve the rates of fully randomized codes. Second, akin to the dirty paper coding problem, we study the impact of an additional interference known to the transmitter. We provide partial capacity results that differ significantly from the standard AVC. Third, we revisit a Gaussian MIMO AVC in which the interference is arbitrary but of limited dimension.
TRASA: TRaffic Aware Slot Assignment Algorithm in Wireless Sensor Networks
Venue: arXiv cs.NI 2012
Year: 2012

In data gathering applications which is a typical application paradigm in wireless sensor networks, sensor nodes may have different traffic demands. Assigning equal channel access to each node may lead to congestion, inefficient use of the bandwidth and decrease of the application performance. In this paper, we prove that the time slot assignment problem is NP-complete when p-hop nodes are not assigned the same slot, with 1 <= p <= h for any strictly positive integer h. We propose TRASA, a TRaffic Aware time Slot Assignment algorithm able to allocate slots to sensors proportionally to their demand. We evaluate the performance of TRASA for different heuristics and prove that it provides an optimized spatial reuse and a minimized cycle length.
Spatio-Temporal Small Worlds for Decentralized Information Retrieval in Social Networking
Venue: arXiv cs.SI 2012
Year: 2012

We discuss foundations and options for alternative, agent-based information retrieval (IR) approaches in Social Networking, especially Decentralized and Mobile Social Networking scenarios. In addition to usual semantic contexts, these approaches make use of long-term social and spatio-temporal contexts in order to satisfy conscious as well as unconscious information needs according to Human IR heuristics. Using a large Twitter dataset, we investigate these approaches and especially investigate the question in how far spatio-temporal contexts can act as a conceptual bracket implicating social and semantic cohesion, giving rise to the concept of Spatio-Temporal Small Worlds.
Decoding of Subspace Codes, a Problem of Schubert Calculus over Finite Fields
Venue: arXiv cs.IT 2012
Year: 2012

Schubert calculus provides algebraic tools to solve enumerative problems. There have been several applied problems in systems theory, linear algebra and physics which were studied by means of Schubert calculus. The method is most powerful when the base field is algebraically closed. In this article we first review some of the successes Schubert calculus had in the past. Then we show how the problem of decoding of subspace codes used in random network coding can be formulated as a problem in Schubert calculus. Since for this application the base field has to be assumed to be a finite field new techniques will have to be developed in the future.
Community Detection in the Labelled Stochastic Block Model
Venue: arXiv cs.SI 2012
Year: 2012

We consider the problem of community detection from observed interactions between individuals, in the context where multiple types of interaction are possible. We use labelled stochastic block models to represent the observed data, where labels correspond to interaction types. Focusing on a two-community scenario, we conjecture a threshold for the problem of reconstructing the hidden communities in a way that is correlated with the true partition. To substantiate the conjecture, we prove that the given threshold correctly identifies a transition on the behaviour of belief propagation from insensitive to sensitive. We further prove that the same threshold corresponds to the transition in a related inference problem on a tree model from infeasible to feasible. Finally, numerical results using belief propagation for community detection give further support to the conjecture.
Unit Disk Cover Problem
Venue: arXiv cs.CG 2012
Year: 2012

Given a set ${\cal D}$ of unit disks in the Euclidean plane, we consider (i) the {\it discrete unit disk cover} (DUDC) problem and (ii) the {\it rectangular region cover} (RRC) problem. In the DUDC problem, for a given set ${\cal P}$ of points the objective is to select minimum cardinality subset ${\cal D}^* \subseteq {\cal D}$ such that each point in ${\cal P}$ is covered by at least one disk in ${\cal D}^*$. On the other hand, in the RRC problem the objective is to select minimum cardinality subset ${\cal D}^{**} \subseteq {\cal D}$ such that each point of a given rectangular region ${\cal R}$ is covered by a disk in ${\cal D}^{**}$. For the DUDC problem, we propose an $(9+ε)$-factor ($0 < ε\leq 6$) approximation algorithm. The previous best known approximation factor was 15 \cite{FL12}. For the RRC problem, we propose (i) an $(9 + ε)$-factor ($0 < ε\leq 6$) approximation algorithm, (ii) an 2.25-factor approximation algorithm in reduce radius setup, improving previous 4-factor approximation result in the same setup \cite{FKKLS07}. The solution of DUDC problem is based on a PTAS for the subproblem LSDUDC, where all the points in ${\cal P}$ are on one side of a line and covered by the disks centered on the other side of that line.
The Complexity of Multi-Mean-Payoff and Multi-Energy Games
Venue: arXiv cs.GT 2012
Year: 2012

In mean-payoff games, the objective of the protagonist is to ensure that the limit average of an infinite sequence of numeric weights is nonnegative. In energy games, the objective is to ensure that the running sum of weights is always nonnegative. Multi-mean-payoff and multi-energy games replace individual weights by tuples, and the limit average (resp. running sum) of each coordinate must be (resp. remain) nonnegative. These games have applications in the synthesis of resource-bounded processes with multiple resources. We prove the finite-memory determinacy of multi-energy games and show the inter-reducibility of multimean-payoff and multi-energy games for finite-memory strategies. We also improve the computational complexity for solving both classes of games with finite-memory strategies: while the previously best known upper bound was EXPSPACE, and no lower bound was known, we give an optimal coNP-complete bound. For memoryless strategies, we show that the problem of deciding the existence of a winning strategy for the protagonist is NP-complete. Finally we present the first solution of multi-meanpayoff games with infinite-memory strategies. We show that multi-mean-payoff games with mean-payoff-sup objectives can be decided in NP and coNP, whereas multi-mean-payoff games with mean-payoff-inf objectives are coNP-complete.
Cayley graphs and analysis of quantum cost for reversible circuit synthesis
Venue: arXiv cs.DM 2012
Year: 2012

We propose the theory of Cayley graphs as a framework to analyse gate counts and quantum costs resulting from reversible circuit synthesis. Several methods have been proposed in the reversible logic synthesis literature by considering different libraries whose gates are associated to the generating sets of certain Cayley graphs. In a Cayley graph, the distance between two vertices corresponds to the optimal circuit size. The lower bound for the diameter of Cayley graphs is also a lower bound for the worst case for any algorithm that uses the corresponding gate library. In this paper, we study two Cayley graphs on the Symmetric Group $S_{2^n}$: the first, denoted by $I_n$, is defined by a generating set associated to generalized Toffoli gates; and the second, the hypercube Cayley graph $H_n$, is defined by a generating set associated to multiple-control Toffoli gates. Those two Cayley graphs have degree $n2^{n-1}$ and order $2^n!$. Maslov, Dueck and Miller proposed a reversible circuit synthesis that we model by the Cayley graph $I_n$. We propose a synthesis algorithm based on the Cayley graph $H_n$ with upper bound of $(n-1)2^{n}+1$ multiple-control Toffoli gates. In addition, the diameter of the Cayley graph $H_n$ gives a lower bound of $n2^{n-1}$.
Normal Factor Graphs as Probabilistic Models
Venue: arXiv cs.IT 2012
Year: 2012

We present a new probabilistic modelling framework based on the recent notion of normal factor graph (NFG). We show that the proposed NFG models and their transformations unify some existing models such as factor graphs, convolutional factor graphs, and cumulative distribution networks. The two subclasses of the NFG models, namely the constrained and generative models, exhibit a duality in their dependence structure. Transformation of NFG models further extends the power of this modelling framework. We point out the well-known NFG representations of parity and generator realizations of a linear code as generative and constrained models, and comment on a more prevailing duality in this context. Finally, we address the algorithmic aspect of computing the exterior function of NFGs and the inference problem on NFGs.
Storage Workload Modelling by Hidden Markov Models: Application to FLASH Memory
Venue: arXiv cs.PF 2012
Year: 2012

A workload analysis technique is presented that processes data from operation type traces and creates a Hidden Markov Model (HMM) to represent the workload that generated those traces. The HMM can be used to create representative traces for performance models, such as simulators, avoiding the need to repeatedly acquire suitable traces. It can also be used to estimate directly the transition probabilities and rates of a Markov modulated arrival process, for use as input to an analytical performance model of Flash memory. The HMMs obtained from industrial workloads are validated by comparing their autocorrelation functions and other statistics with those of the corresponding monitored time series. Further, the performance model applications are illustrated by numerical examples.
New Transience Bounds for Long Walks
Venue: arXiv cs.DM 2012
Year: 2012

Linear max-plus systems describe the behavior of a large variety of complex systems. It is known that these systems show a periodic behavior after an initial transient phase. Assessment of the length of this transient phase provides important information on complexity measures of such systems, and so is crucial in system design. We identify relevant parameters in a graph representation of these systems and propose a modular strategy to derive new upper bounds on the length of the transient phase. By that we are the first to give asymptotically tight and potentially subquadratic transience bounds. We use our bounds to derive new complexity results, in particular in distributed computing.
Distributed Resource Allocation Algorithm Design for Multi-Cell Networks Based on Advanced Decomposition Theory
Venue: arXiv cs.IT 2012
Year: 2012

In this letter, we investigate the resource allocation for downlink multi-cell coordinated OFDMA wireless networks, in which power allocation and subcarrier scheduling are jointly optimized. Aiming at maximizing the weighted sum of the minimal user rates (WSMR) of coordinated cells under individual power constraints at each base station, an effective distributed resource allocation algorithm using a modified decomposition method is proposed, which is suitable by practical implementation due to its low complexity and fast convergence speed. Simulation results demonstrate that the proposed decentralized algorithm provides substantial throughput gains with lower computational cost compared to existing schemes.