OpenRaiser/Intern-Atlas huggingface dataset:
SClib, a hack for straightforward embedded C functions in Python
Venue: arXiv cs.MS 2014
Year: 2014

We present SClib, a simple hack that allows easy and straightforward evaluation of C functions within Python code, boosting flexibility for better trade-off between computation power and feature availability, such as visualization and existing computation routines in SciPy. We also present two cases were SClib has been used. In the first set of applications we use SClib to write a port to Python of a Schrödinger equation solver that has been extensively used the literature, the resulting script presents a speed-up of about 150x with respect to the original one. A review of the situations where the speeded-up script has been used is presented. We also describe the solution to the related problem of solving a set of coupled Schrödinger-like equations where SClib is used to implement the speed-critical parts of the code. We argue that when using SClib within IPython we can use NumPy and Matplotlib for the manipulation and visualization of the solutions in an interactive environment with no performance compromise. The second case is an engineering application. We use SClib to evaluate the control and system derivatives in a feedback control loop for electrical motors. With this and the integration routines available in SciPy, we can run simulations of the control loop a la Simulink. The use of C code not only boosts the speed of the simulations, but also enables to test the exact same code that we use in the test rig to get experimental results. Again, integration with IPython gives us the flexibility to analyze and visualize the data.
Toward Refactoring of DMARF and GIPSY Case Studies a Team 7 SOEN6471-S14 Project Report
Venue: arXiv cs.SE 2014
Year: 2014

Software architecture is defined as the process of a well-structured solution that meets all of the technical and operational requirements, as well as improving the quality attributes of the system such as readability, Reliability, maintainability, and performance. It involves a series of design decisions that can have a considerable impact on the systems quality attributes, and on the overall success of the application. In this work, we start with analysis and investigation of two open source software (OSS) platforms DMARF and GIPSY, predominantly implemented in Java. Many research papers have been studied in order to gain more insights and clear background about their architectures, enhancement, evolution, challenges, and features. Subsequently, we extract and find their needs, high-level requirements, and architectural structures which lead to important design decisions and thus influence their quality attributes. Primarily, we reversed engineering each system0s source code to reconstruct its domain model and class diagram model. We tried to achieve the traceability between requirements and other design artifacts to be consistent. Additionally, we conducted both manual and automated refactoring techniques to get rid of some existing code smells to end up with more readable and understandable code without affecting its observable behavior.
Spin-Orbit Torque Induced Spike-Timing Dependent Plasticity
Venue: arXiv cs.ET 2014
Year: 2014

Nanoelectronic devices that mimic the functionality of synapses are a crucial requirement for performing cortical simulations of the brain. In this work we propose a ferromagnet-heavy metal heterostructure that employs spin-orbit torque to implement Spike-Timing Dependent Plasticity. The proposed device offers the advantage of decoupled spike transmission and programming current paths, thereby leading to reliable operation during online learning. Possible arrangement of such devices in a crosspoint architecture can pave the way for ultra-dense neural networks. Simulation studies indicate that the device has the potential of achieving pico-Joule level energy consumption (maximum 2 pJ per synaptic event) which is comparable to the energy consumption for synaptic events in biological synapses.
The Foundation of Big Data: Experiments, Formulation, and Applications
Venue: arXiv cs.IT 2014
Year: 2014

The central theme of this talk is to promote the non-asymptotic statistical viewpoint in the context of massive datasets. The classical viewpoint breaks down when the data size becomes large.
First Passage Value
Venue: arXiv cs.SY 2014
Year: 2014

For many stochastic dynamic systems, the Mean First Passage Time (MFPT) is a useful concept, which gives expected time before a state of interest. This work is an extension of MFPT in several ways. (1) We show that for some systems the system-wide MFPT, calculated using the second largest eigenvalue only, captures most of the fundamental dynamics, even for quite complex, high-dimensional systems. (2) We generalize MFPT to Mean First Passage Value (MFPV), which gives a more general value of interest, e.g., energy expenditure, distance, or time. (3) We provide bounds on First Passage Value (FPV) for a given confidence level. At the heart of this work, we emphasize that for our goals, many hybrid systems can be approximated as Markov Decision Processes. So, many systems can be controlled effectively using this framework. However, our framework is particularly useful for metastable systems. Such systems exhibit interesting long-living behaviors from which they are guaranteed to inevitably escape (e.g., eventually arriving at a distinct failure or success state). Our goal is then either minimizing or maximizing the value until escape, depending on the application.
Mixture of Parts Revisited: Expressive Part Interactions for Pose Estimation
Venue: arXiv cs.CV 2014
Year: 2014

Part-based models with restrictive tree-structured interactions for the Human Pose Estimation problem, leaves many part interactions unhandled. Two of the most common and strong manifestations of such unhandled interactions are self-occlusion among the parts and the confusion in the localization of the non-adjacent symmetric parts. By handling the self-occlusion in a data efficient manner, we improve the performance of the basic Mixture of Parts model by a large margin, especially on uncommon poses. Through addressing the confusion in the symmetric limb localization using a combination of two complementing trees, we improve the performance on all the parts by atmost doubling the running time. Finally, we show that the combination of the two solutions improves the results. We report results that are equivalent to the state-of-the-art on two standard datasets. Because of maintaining the tree-structured interactions and only part-level modeling of the base Mixture of Parts model, this is achieved in time that is much less than the best performing part-based model.
Equivalence of lower bounds on the number of perfect pairs
Venue: arXiv cs.DM 2014
Year: 2014

Let c(F) be the number of perfect pairs of F and c(G) be the maximum of c(F) over all (near-) one-factorizations F of G. Wagner showed that for odd n, c(K_{n}) \geq n*phi(n)/2 and for m and n which are odd and co-prime to each other, c(K_{mn}) \geq 2*c(K_{m})*c(K_{n}). In this note, we establish that both these results are equivalent in the sense that they both give rise to the same lower bound.
iPersea : The Improved Persea with Sybil Detection Mechanism
Venue: arXiv cs.CR 2014
Year: 2014

P2P systems are highly susceptible to Sybil attacks, in which an attacker creates a large number of identities and uses them to control a substantial fraction of the system. Persea is the most recent approach towards designing a social network based Sybil-resistant DHT. Unlike prior Sybil-resistant P2P systems based on social networks, Persea does not rely on two key assumptions: (i) that the social network is fast mixing, and (ii) that there is a small ratio of attack edges to honest peers. Both assumptions have been shown to be unreliable in real social networks. The hierarchical distribution of node IDs in Persea confines a large attacker botnet to a considerably smaller region of the ID space than in a normal P2P system and its replication mechanism lets a peer to retrieve the desired results even if a given region is occupied by attackers. However, Persea system suffers from certain limitations, since it cannot handle the scenario, where the malicious target returns an incorrect result instead of just ignoring the lookup request. In this paper, we address this major limitation of Persea through a Sybil detection mechanism built on top of Persea system, which accommodates inspection lookup, a specially designed lookup scheme to detect the Sybil nodes based on their responses to the lookup query. We design a scheme to filter those detected Sybils to ensure the participation of honest nodes on the lookup path during regular DHT lookup. Since the malicious nodes are opt-out from the lookup path in our system, they cannot return any incorrect result during regular lookup. We evaluate our system in simulations with social network datasets and the results show that catster, the largest network in our simulation with 149700 nodes and 5449275 edges, gains 100% lookup success rate, even when the number of attack edges is equal to the number of benign peers in the network.
Probability Estimates for Fading and Wiretap Channels from Ideal Class Zeta Functions
Venue: arXiv cs.IT 2014
Year: 2014

In this paper, new probability estimates are derived for ideal lattice codes from totally real number fields using ideal class Dedekind zeta functions. In contrast to previous work on the subject, it is not assumed that the ideal in question is principal. In particular, it is shown that the corresponding inverse norm sum depends not only on the regulator and discriminant of the number field, but also on the values of the ideal class Dedekind zeta functions. Along the way, we derive an estimate of the number of elements in a given ideal with a certain algebraic norm within a finite hypercube. We provide several examples which measure the accuracy and predictive ability of our theorems.
Discrete Load Balancing in Heterogeneous Networks with a Focus on Second-Order Diffusion
Venue: arXiv cs.DC 2014
Year: 2014

In this paper we consider a wide class of discrete diffusion load balancing algorithms. The problem is defined as follows. We are given an interconnection network and a number of load items, which are arbitrarily distributed among the nodes of the network. The goal is to redistribute the load in iterative discrete steps such that at the end each node has (almost) the same number of items. In diffusion load balancing nodes are only allowed to balance their load with their direct neighbors. We show three main results. Firstly, we present a general framework for randomly rounding the flow generated by continuous diffusion schemes over the edges of a graph in order to obtain corresponding discrete schemes. Compared to the results of Rabani, Sinclair, and Wanka, FOCS'98, which are only valid w.r.t. the class of homogeneous first order schemes, our framework can be used to analyze a larger class of diffusion algorithms, such as algorithms for heterogeneous networks and second order schemes. Secondly, we bound the deviation between randomized second order schemes and their continuous counterparts. Finally, we provide a bound for the minimum initial load in a network that is sufficient to prevent the occurrence of negative load at a node during the execution of second order diffusion schemes. Our theoretical results are complemented with extensive simulations on different graph classes. We show empirically that second order schemes, which are usually much faster than first order schemes, will not balance the load completely on a number of networks within reasonable time. However, the maximum load difference at the end seems to be bounded by a constant value, which can be further decreased if first order scheme is applied once this value is achieved by second order scheme.
Search Methods for Tile Sets in Patterned DNA Self-Assembly
Venue: arXiv cs.ET 2014
Year: 2014

The Pattern self-Assembly Tile set Synthesis (PATS) problem, which arises in the theory of structured DNA self-assembly, is to determine a set of coloured tiles that, starting from a bordering seed structure, self-assembles to a given rectangular colour pattern. The task of finding minimum-size tile sets is known to be NP-hard. We explore several complete and incomplete search techniques for finding minimal, or at least small, tile sets and also assess the reliability of the solutions obtained according to the kinetic Tile Assembly Model.
Load Balancing Optimization in LTE/LTE-A Cellular Networks: A Review
Venue: arXiv cs.NI 2014
Year: 2014

During the past few decades wireless technology has seen a tremendous growth. The recent introduction of high-end mobile devices has further increased subscriber's demand for high bandwidth. Current cellular systems require manual configuration and management of networks, which is now costly, time consuming and error prone due to exponentially increasing rate of mobile users and nodes. This leads to introduction of self organizing capabilities for network management with minimum human involvement. It is expected to permit higher end user Quality of Service (QoS) along with less operational and maintenance cost for telecom service providers. Self organized cellular networks incorporate a collection of functions for automatic configuration, optimization and maintenance of cellular networks. As mobile end users continue to use network resources while moving from a cell boundary to other, traffic load within a cell does not remain constant. Thus Load balancing as a part of self organized network solution, has become one of the most active and emerging fields of research in Cellular Network. It involves transfer of load from overloaded cells to the neighbouring cells with free resources for more balanced load distribution in order to maintain appropriate end-user experience and network performance. In this paper, review of various load balancing techniques currently used in mobile networks is presented, with special emphasis on techniques that are suitable for self optimization feature in future cellular networks.
Accurate Community Detection in the Stochastic Block Model via Spectral Algorithms
Venue: arXiv cs.SI 2014
Year: 2014

We consider the problem of community detection in the Stochastic Block Model with a finite number $K$ of communities of sizes linearly growing with the network size $n$. This model consists in a random graph such that each pair of vertices is connected independently with probability $p$ within communities and $q$ across communities. One observes a realization of this random graph, and the objective is to reconstruct the communities from this observation. We show that under spectral algorithms, the number of misclassified vertices does not exceed $s$ with high probability as $n$ grows large, whenever $pn=ω(1)$, $s=o(n)$ and \begin{equation*} \lim\inf_{n\to\infty} {n(α_1 p+α_2 q-(α_1 + α_2)p^{\frac{α_1}{α_1 + α_2}}q^{\frac{α_2}{α_1 + α_2}})\over \log (\frac{n}{s})} >1,\quad\quad(1) \end{equation*} where $α_1$ and $α_2$ denote the (fixed) proportions of vertices in the two smallest communities. In view of recent work by Abbe et al. and Mossel et al., this establishes that the proposed spectral algorithms are able to exactly recover communities whenever this is at all possible in the case of networks with two communities with equal sizes. We conjecture that condition (1) is actually necessary to obtain less than $s$ misclassified vertices asymptotically, which would establish the optimality of spectral method in more general scenarios.
Turning Bitcoins into the Best-coins
Venue: arXiv cs.CR 2014
Year: 2014

In this paper we discuss Bitcoin, the leader among the existing cryptocurrencies, to analyse its trends, success factors, current challenges and probable solutions to make it even better. In the introduction section, we discuss the history and working mechanism of Bitcoin. In the background section, we develop the ideas that evolved in the process of making a stable cryptocurrency. We also analyze the survey matrices of the present day cryptocurrencies. This survey clearly shows that Bitcoin is the clear winner among its kind. Section 3 is about the success factors of Bitcoin and the proceeding sections are a discussion about current challenges which pose as hurdles in making Bitcoin a better currency in the digital world. We finally discuss the balance between anonymity and reduced trust in the cryptocurrency world, before concluding the survey.
Toward Refactoring of DMARF and GIPSY Case Studies -- a Team 12 SOEN6471-S14 Project Report
Venue: arXiv cs.SE 2014
Year: 2014

The main significance of this document is two source systems namely GIPSY and DMARF. Intensional languages are required like GIPSY for absoluteness and forward practical investigations on the subject.DMARF mainly focuses on software architectural design and implementation on Distributed Audio recognition and its applications such as speaker identification which can run distributively on web services architecture. This mainly highlights security aspects in a distributed system, the Java data security framework (JDSF) in DMARF. ASSL (Autonomic System Specification Language) frame work is used to integrate a self-optimizing property for DMARF. GIPSY mainly depends on Higher-Order Intensional Logic (HOIL) and reflects three main goals Generality, Adaptability and Efficiency.
Towards Refactoring of DMARF and GIPSY Case Studies -- A Team 5 SOEN6471-S14 Project Report
Venue: arXiv cs.SE 2014
Year: 2014

This paper presents an analysis of the architectural design of two distributed open source systems (OSS) developed in Java: Distributed Modular Audio Recognition Framework (DMARF) and General Intensional Programming System (GIPSY). The research starts with a background study of these frameworks to determine their overall architectures. Afterwards, we identify the actors and stakeholders and draft a domain model for each framework. Next, we evaluated and proposed a fused DMARF over GIPSY Run-time Architecture (DoGRTA) as a domain concept. Later on, the team extracted and studied the actual class diagrams and determined classes of interest. Next, we identified design patterns that were present within the code of each framework. Finally, code smells in the source code were detected using popular tools and a selected number of those identified smells were refactored using established techniques and implemented in the final source code. Tests were written and ran prior and after the refactoring to check for any behavioral changes.
Towards Refactoring of DMARF and GIPSY Case Studies -- a Team 8 SOEN6471-S14 Project Report
Venue: arXiv cs.SE 2014
Year: 2014

Of the factors that determines the quality of a software system is its design and architecture. Having a good and clear design and architecture allows the system to evolve (plan and add new features), be easier to comprehend, easier to develop, easier to maintain; and in conclusion increase the life time of the, and being more competitive in its market. In the following paper we study the architecture of two different systems: GIPSY and DMARF. This paper provides a general overview of these two systems. What are these two systems, purpose, architecture, and their design patterns? Classes with week architecture and design, and code smells were also identified and some refactorings were suggested and implemented. Several tools were used throughout the paper for several purpose. LOGICSCOPE, JDeodoant, McCabe were used to identify classes with weak designs and code smells. Other tools and plugins were also used to identify class designs and relationships between classes such as ObjectAid (Eclipse plugin).
A Polynomial Kernel for Trivially Perfect Editing
Venue: arXiv cs.DS 2014
Year: 2014

We give a kernel with $O(k^7)$ vertices for Trivially Perfect Editing, the problem of adding or removing at most $k$ edges in order to make a given graph trivially perfect. This answers in affirmative an open question posed by Nastos and Gao, and by Liu et al. Our general technique implies also the existence of kernels of the same size for the related problems Trivially Perfect Completion and Trivially Perfect Deletion. Whereas for the former an $O(k^3)$ kernel was given by Guo, for the latter no polynomial kernel was known. We complement our study of Trivially Perfect Editing by proving that, contrary to Trivially Perfect Completion, it cannot be solved in time $2^{o(k)} \cdot n^{O(1)}$ unless the Exponential Time Hypothesis fails. In this manner we complete the picture of the parameterized and kernelization complexity of the classic edge modification problems for the class of trivially perfect graphs.
Communication Performance Analysis of Sampled-Data H-infinity Optimal Coupling Wave Canceler
Venue: arXiv cs.IT 2014
Year: 2014

In this manuscript, we propose a design method of digital filters which cancel coupling waves generated in single-frequency full-duplex wireless relay stations by using the sampled-data H-infinity control theory. Simulation results show effectiveness of the proposed method to communication performance from a base station to a terminal.
Register Spilling for Specific Application Domains in Application Specific Instruction-set Processors
Venue: arXiv cs.PL 2014
Year: 2014

An Application Specific Instruction set Processor (ASIP) is an important component in designing embedded systems. One of the problems in designing an instruction set for such processors is determining the number of registers is needed in the processor that will optimize the computational time and the cost. The performance of a processor may fall short due to register spilling, which is caused by the lack of available registers in a processor. In the design perspective, it will result in processors with great performance and low power consumption if we can avoid register spilling by deciding a value for the number of registers needed in an ASIP. However, as of now, it has not clearly been recognized how the number of registers changes with different application domains. In this paper, we evaluated whether different application domains have any significant effect on register spilling and therefore the performance of a processor so that we could use different number of registers when building ASIPs for different application domains rather than using a constant set of registers. Such utilization of registers will result in processors with high performance, low cost and low power consumption.
Shortest Path Analysis in Social Graphs
Venue: arXiv cs.SI 2014
Year: 2014

The shortest path problem is among the most fundamental combinatorial optimization problems to answer reachability queries. It is hard to deter-mine which vertices or edges are visited during shortest path traversals. In this paper, we provide an empirical analysis on how traversal algorithms behave on social networks. First, we compute the shortest paths between set of vertices. Each shortest path is considered as one transaction. Second, we utilize the pat-tern mining approach to identify the frequency of occurrence of the vertices. We evaluate the results in terms of network properties, i.e. degree distribution, clustering coefficient.