OpenRaiser/Intern-Atlas huggingface dataset:
Are topic-specific search term, journal name and author name recommendations relevant for researchers?
Venue: arXiv cs.DL 2014
Year: 2014

In this paper we describe a case study where researchers in the social sciences (n=19) assess topical relevance for controlled search terms, journal names and author names which have been compiled automatically by bibliometric-enhanced information retrieval (IR) services. We call these bibliometric-enhanced IR services Search Term Recommender (STR), Journal Name Recommender (JNR) and Author Name Recommender (ANR) in this paper. The researchers in our study (practitioners, PhD students and postdocs) were asked to assess the top n pre-processed recommendations from each recommender for specific research topics which have been named by them in an interview before the experiment. Our results show clearly that the presented search term, journal name and author name recommendations are highly relevant to the researchers' topic and can easily be integrated for search in Digital Libraries. The average precision for top ranked recommendations is 0.75 for author names, 0.74 for search terms and 0.73 for journal names. The relevance distribution differs largely across topics and researcher types. Practitioners seem to favor author name recommendations while postdocs have rated author name recommendations the lowest. In the experiment the small postdoc group (n=3) favor journal name recommendations.
Cloud WorkBench - Infrastructure-as-Code Based Cloud Benchmarking
Venue: arXiv cs.SE 2014
Year: 2014

To optimally deploy their applications, users of Infrastructure-as-a-Service clouds are required to evaluate the costs and performance of different combinations of cloud configurations to find out which combination provides the best service level for their specific application. Unfortunately, benchmarking cloud services is cumbersome and error-prone. In this paper, we propose an architecture and concrete implementation of a cloud benchmarking Web service, which fosters the definition of reusable and representative benchmarks. In distinction to existing work, our system is based on the notion of Infrastructure-as-Code, which is a state of the art concept to define IT infrastructure in a reproducible, well-defined, and testable way. We demonstrate our system based on an illustrative case study, in which we measure and compare the disk IO speeds of different instance and storage types in Amazon EC2.
Kriging based Surrogate Modeling for Fractional Order Control of Microgrids
Venue: arXiv cs.SY 2014
Year: 2014

This paper investigates the use of fractional order (FO) controllers for a microgrid. The microgrid employs various autonomous generation systems like wind turbine generator (WTG), solar photovoltaic (PV), diesel energy generator (DEG) and fuel-cells (FC). Other storage devices like the battery energy storage system (BESS) and the flywheel energy storage system (FESS) are also present in the power network. An FO control strategy is employed and the FO-PID controller parameters are tuned with a global optimization algorithm to meet system performance specifications. A kriging based surrogate modeling technique is employed to alleviate the issue of expensive objective function evaluation for the optimization based controller tuning. Numerical simulations are reported to prove the validity of the proposed methods. The results for both the FO and the integer order (IO) controllers are compared with standard evolutionary optimization techniques and the relative merits and demerits of the kriging based surrogate modeling are discussed. This kind of optimization technique is not only limited to this specific case of microgrid control but also can be ported to other computationally expensive power system optimization problems.
GIMP and Wavelets for Medical Image Processing: Enhancing Images of the Fundus of the Eye
Venue: arXiv cs.CV 2014
Year: 2014

The visual analysis of retina and of its vascular characteristics is important in the diagnosis and monitoring of diseases of visual perception. In the related medical diagnoses, the digital processing of the fundus images is used to obtain the segmentation of retinal vessels. However, an image segmentation is often requiring methods based on peculiar or complex algorithms: in this paper we will show some alternative approaches obtained by applying freely available tools to enhance, without a specific segmentation, the images of the fundus of the eye. We will see in particular, that combining the use of GIMP, the GNU Image Manipulation Program, with the wavelet filter of Iris, a program well-known for processing astronomical images, the result is giving images which can be alternative of those obtained from segmentation.
Making FPGAs Accessible to Scientists and Engineers as Domain Expert Software Programmers with LabVIEW
Venue: arXiv cs.SE 2014
Year: 2014

In this paper we present a graphical programming framework, LabVIEW, and associated language and libraries, as well as programming techniques and patterns that we have found useful in making FPGAs accessible to scientists and engineers as domain expert software programmers.
Tools and Techniques for Efficient High-Level System Design on FPGAs
Venue: arXiv cs.OH 2014
Year: 2014

In order for FPGAs to be successful outside traditional markets, tools which enable software programmers to achieve high levels of system performance while abstracting away the FPGA-specific details are needed. DSPB Builder Advanced (DSPBA) is one such tool. DSPBA provides model-based design environment using Matlab's Simulink frontend that decouples the fully-algorithmic design description from the details of FPGA system generation. DSPBA offers several levels of debugging: from Simulink scopes to bit-accurate-simulation and silver reference models. It also offers the most comprehensive set of fixed-point, floating-point and signal-processing IPs available today. The combination of 7 floating-point precisions, fused-datapath support, custom operator support and automated folding allows exploring the best tradeoffs between accuracy, size and throughput. The DSPBA backend protects users from the details of device-dependent operator mapping offering both efficiency and prompt support for new devices and features such as the Arria10 floating-point cores. The collection of features available in DSPBA allows both unexperienced and expert users to efficiently migrate performance-crucial systems to the FPGA architecture.
Wireless-Powered Cooperative Communications via a Hybrid Relay
Venue: arXiv cs.IT 2014
Year: 2014

In this paper, we consider a wireless-powered cooperative communication network, which consists of a hybrid access-point (AP), a hybrid relay, and an information source. In contrast to the conventional cooperative networks, the source in the considered network is assumed to have no embedded energy supply. Thus, it first needs to harvest energy from the signals broadcast by the AP and/or relay, which have constant power supply, in the downlink (DL) before transmitting the information to the AP in the uplink (UL). The hybrid relay can not only help to forward information in the UL but also charge the source with wireless energy transfer in the DL. Considering different possible operations of the hybrid relay, we propose two cooperative protocols for the considered network. We jointly optimize the time and power allocation for DL energy transfer and UL information transmission to maximize the system throughput of the proposed protocols. Numerical results are presented to compare the performance of the proposed protocols and illustrate the impacts of system parameters.
Remarks on the Cryptographic Primitive of Attribute-based Encryption
Venue: arXiv cs.CR 2014
Year: 2014

Attribute-based encryption (ABE) which allows users to encrypt and decrypt messages based on user attributes is a type of one-to-many encryption. Unlike the conventional one-to-one encryption which has no intention to exclude any partners of the intended receiver from obtaining the plaintext, an ABE system tries to exclude some unintended recipients from obtaining the plaintext whether they are partners of some intended recipients. We remark that this requirement for ABE is very hard to meet. An ABE system cannot truly exclude some unintended recipients from decryption because some users can exchange their decryption keys in order to maximize their own interests. The flaw discounts the importance of the cryptographic primitive.
Best Operator Policy in a Heterogeneous Wireless Network
Venue: arXiv cs.NI 2014
Year: 2014

In this paper, we perform a business analysis of our hybrid decision algorithm for the selection of the access in a multi-operator networks environment. We investigate the ability of the operator to express his strategy and influence the access selection for his client. In this purpose, we study two important coefficients of the previously proposed cost function, Wu and Wop, and show that the value of these coefficients is not arbitrary. Simulation results show that the value of the ratio Wu/Wop enables a selection decision respecting operator's strategy and it affects the achieved global profit for all cooperating operators.
Optimal Radius for Connectivity in Duty-Cycled Wireless Sensor Networks
Venue: arXiv cs.NI 2014
Year: 2014

We investigate the condition on transmission radius needed to achieve connectivity in duty-cycled wireless sensor networks (briefly, DC-WSN). First, we settle a conjecture of Das et. al. (2012) and prove that the connectivity condition on Random Geometric Graphs (RGG), given by Gupta and Kumar (1989), can be used to derive a weak sufficient condition to achieve connectivity in DC-WSN. To find a stronger result, we define a new vertex-based random connection model which is of independent interest. Following a proof technique of Penrose (1991) we prove that when the density of the nodes approaches infinity then a finite component of size greater than 1 exists with probability 0 in this model. We use this result to obtain an optimal condition on node transmission radius which is both necessary and sufficient to achieve connectivity and is hence optimal. The optimality of such a radius is also tested via simulation for two specific duty-cycle schemes, called the contiguous and the random selection duty-cycle scheme. Finally, we design a minimum-radius duty-cycling scheme that achieves connectivity with a transmission radius arbitrarily close to the one required in Random Geometric Graphs. The overhead in this case is that we have to spend some time computing the schedule.
The curriculum prerequisite network: a tool for visualizing and analyzing academic curricula
Venue: arXiv cs.SI 2014
Year: 2014

This article advances the prerequisite network as a means to visualize the hidden structure in an academic curriculum. Network technologies have been used for some time now in social analyses and more recently in biology in the areas of genomics and systems biology. Here I treat the curriculum as a complex system with nodes representing courses and links between nodes the course prerequisites as readily obtained from a course catalogue. The resulting curriculum prerequisite network can be rendered as a directed acyclic graph, which has certain desirable analytical features. The curriculum is seen as partitioned into numerous isolated course groupings, the size of the groups varying considerably. Individual courses are seen serving very different roles in the overall organization, such as information sources, hubs, and bridges. This network represents the intrinsic, hard-wired constraints on the flow of information in a curriculum, and is the organizational context within which learning occurs.
Dynamic Sweep Filtering Algorithm for FlexC
Venue: arXiv cs.AI 2014
Year: 2014

We investigate cumulative scheduling in uncertain environments, using constraint programming. We detail in this paper the dynamic sweep filtering algorithm of the FlexC global constraint.
Neural Mechanism of Language
Venue: arXiv cs.NE 2014
Year: 2014

This paper is based on our previous work on neural coding. It is a self-organized model supported by existing evidences. Firstly, we briefly introduce this model in this paper, and then we explain the neural mechanism of language and reasoning with it. Moreover, we find that the position of an area determines its importance. Specifically, language relevant areas are in the capital position of the cortical kingdom. Therefore they are closely related with autonomous consciousness and working memories. In essence, language is a miniature of the real world. Briefly, this paper would like to bridge the gap between molecule mechanism of neurons and advanced functions such as language and reasoning.
Stretchy Polynomial Regression
Venue: arXiv cs.LG 2014
Year: 2014

This article proposes a novel solution for stretchy polynomial regression learning. The solution comes in primal and dual closed-forms similar to that of ridge regression. Essentially, the proposed solution stretches the covariance computation via a power term thereby compresses or amplifies the estimation. Our experiments on both synthetic data and real-world data show effectiveness of the proposed method for compressive learning.
Web Usage mining framework for Data Cleaning and IP address Identification
Venue: arXiv cs.DB 2014
Year: 2014

The World Wide Web is the most wide known information source that is easily available and searchable. It consists of billions of interconnected documents Web pages are authored by millions of people. Accesses made by various users to pages are recorded inside web logs. These log files exist in various formats. Because of increase in usage of web, size of web log files is increasing at a much faster rate. Web mining is application of data mining technique to these log files. It can be of three types Web usage mining, Web structure mining and Web content mining. Web Usage mining is mining of usage patterns of users which can then be used to personalize web sites and create attractive web sites. It consists of three main phases: Preprocessing, Pattern discovery and Pattern analysis. In this paper we focus on Data cleaning and IP Address identification stages of preprocessing. Methodology has been proposed for both the stages. At the end conclusion is made about number of users left after IP address identification.
Bounds for D-finite closure properties
Venue: arXiv cs.SC 2014
Year: 2014

We provide bounds on the size of operators obtained by algorithms for executing D-finite closure properties. For operators of small order, we give bounds on the degree and on the height (bit-size). For higher order operators, we give degree bounds that are parameterized with respect to the order and reflect the phenomenon that higher order operators may have lower degrees (order-degree curves).
HyDA-Vista: Towards Optimal Guided Selection of k-mer Size for Sequence Assembly
Venue: arXiv cs.CE 2014
Year: 2014

Motivation: Intimately tied to assembly quality is the complexity of the de Bruijn graph built by the assembler. Thus, there have been many paradigms developed to decrease the complexity of the de Bruijn graph. One obvious combinatorial paradigm for this is to allow the value of $k$ to vary; having a larger value of $k$ where the graph is more complex and a smaller value of $k$ where the graph would likely contain fewer spurious edges and vertices. One open problem that affects the practicality of this method is how to predict the value of $k$ prior to building the de Bruijn graph. We show that optimal values of $k$ can be predicted prior to assembly by using the information contained in a phylogenetically-close genome and therefore, help make the use of multiple values of $k$ practical for genome assembly. Results: We present HyDA-Vista, which is a genome assembler that uses homology information to choose a value of $k$ for each read prior to the de Bruijn graph construction. The chosen $k$ is optimal if there are no sequencing errors and the coverage is sufficient. Fundamental to our method is the construction of the {\em maximal sequence landscape}, which is a data structure that stores for each position in the input string, the largest repeated substring containing that position. In particular, we show the maximal sequence landscape can be constructed in $O(n + n \log n)$-time and $O(n)$-space. HyDA-Vista first constructs the maximal sequence landscape for a homologous genome. The reads are then aligned to this reference genome, and values of $k$ are assigned to each read using the maximal sequence landscape and the alignments. Eventually, all the reads are assembled by an iterative de Bruijn graph construction method. Our results and comparison to other assemblers demonstrate that HyDA-Vista achieves the best assembly of {\em E. coli} before repeat resolution or scaffolding.
Gradient of the Objective Function for an Anisotropic Centroidal Voronoi Tessellation (CVT) - A revised, detailed derivation
Venue: arXiv cs.CG 2014
Year: 2014

In their recent article (2010), Levy and Liu introduced a generalization of Centroidal Voronoi Tessellation (CVT) - namely the Lp-CVT - that allows the computation of an anisotropic CVT over a sound mathematical framework. In this article a new objective function is defined, and both this function and its gradient are derived in closed-form for surfaces and volumes. This method opens a wide range of possibilities, also described in the paper, such as quad-dominant surface remeshing, hex-dominant volume meshing or fully-automated capturing of sharp features. However, in the same paper, the derivations of the gradient and of the new objective function are only partially expanded in the appendices, and some relevant requisites on the anisotropy field are left implicit. In order to better harness the possibilities described there, in this work the entire derivation process is made explicit. In the authors' opinion, this also helps understanding the working conditions of the method and its possible applications.
Structured Random Linear Codes (SRLC): Bridging the Gap between Block and Convolutional Codes
Venue: arXiv cs.IT 2014
Year: 2014

Several types of AL-FEC (Application-Level FEC) codes for the Packet Erasure Channel exist. Random Linear Codes (RLC), where redundancy packets consist of random linear combinations of source packets over a certain finite field, are a simple yet efficient coding technique, for instance massively used for Network Coding applications. However the price to pay is a high encoding and decoding complexity, especially when working on $GF(2^8)$, which seriously limits the number of packets in the encoding window. On the opposite, structured block codes have been designed for situations where the set of source packets is known in advance, for instance with file transfer applications. Here the encoding and decoding complexity is controlled, even for huge block sizes, thanks to the sparse nature of the code and advanced decoding techniques that exploit this sparseness (e.g., Structured Gaussian Elimination). But their design also prevents their use in convolutional use-cases featuring an encoding window that slides over a continuous set of incoming packets. In this work we try to bridge the gap between these two code classes, bringing some structure to RLC codes in order to enlarge the use-cases where they can be efficiently used: in convolutional mode (as any RLC code), but also in block mode with either tiny, medium or large block sizes. We also demonstrate how to design compact signaling for these codes (for encoder/decoder synchronization), which is an essential practical aspect.
Compressing Encrypted Data and Permutation Cipher
Venue: arXiv cs.IT 2014
Year: 2014

In a system that performs both encryption and lossy compression, the conventional way is to compress first and then encrypt the compressed data. This separation approach proves to be optimal. In certain applications where sensitive information should be protected as early as possible, it is preferable to perform encryption first and then compress the encrypted data, which leads to the concept of the reversed system. Johnson et al. proposed an achievability scheme for the reversed system that has a modulo-sum encryption followed by a compression using Wyner-Ziv distributed source coding with side information. However, this reversed system performs worse than the conventional system in the sense that it requires more compression rate and secrecy key rate. In this paper, we propose a new achievability scheme for the reverse system where encryption is conducted by a permutation cipher and then the encrypted data is compressed using the optimal rate-distortion code. The proposed scheme can achieve the optimal compression rate and secret key rate, and therefore shows that reversing the order of encryption and compression does not necessarily compromise the performance of an encryption-compression system. The proposed system attains weak secrecy, and we show that the information leakage is mainly contributed by the type information of the sequence, which is not concealed by the permutation cipher. Given the type of the sequence, the rest of the information leakage vanishes exponentially.
From Software Architecture Structure and Behavior Modeling to Implementations of Cyber-Physical Systems
Venue: arXiv cs.SE 2014
Year: 2014

Software development for Cyber-Physical Systems (CPS) is a sophisticated activity as these systems are inherently complex. The engineering of CPS requires composition and interaction of diverse distributed software modules. Describing both, a systems architecture and behavior in integrated models, yields many advantages to cope with this complexity: the models are platform independent, can be decomposed to be developed independently by experts of the respective fields, are highly reusable and may be subjected to formal analysis. In this paper, we introduce a code generation framework for the MontiArcAutomaton modeling language. CPS are modeled as Component & Connector architectures with embedded I/O! automata. During development, these models can be analyzed using formal methods, graphically edited, and deployed to various platforms. For this, we present four code generators based on the MontiCore code generation framework, that implement the transformation from MontiArcAutomaton models to Mona (formal analysis), EMF Ecore (graphical editing), and Java and Python (deployment. Based on these prototypes, we discuss their commonalities and differences as well as language and application specific challenges focusing on code generator development.
Meta-Metrics for Simulations in Software Engineering on the Example of Integral Safety Systems
Venue: arXiv cs.SE 2014
Year: 2014

Vehicles passengers and other traffic participants are protected more and more by integral safety systems. They continuously perceive the vehicles environment to prevent dangerous situations by e.g. emergency braking systems. Furthermore, increasingly intelligent vehicle functions are still of major interest in research and development to reduce the risk of accidents. However, the development and testing of these functions should not rely only on validations on proving grounds and on long-term test-runs in real traffic; instead, they should be extended by virtual testing approaches to model potentially dangerous situations or to re-run specific traffic situations easily. This article outlines meta-metrics as one of todays challenges for the software engineering of these cyber-physical systems to provide guidance during the system development: For example, unstable results of simulation test-runs over the vehicle functions revision history are elaborated as an indicating metric where to focus on with real or further virtual test-runs; furthermore, varying acting time points for the same virtual traffic situation are indicating problems with the reliability to interpret the specific situation. In this article, several of such meta-metrics are discussed and assigned both to different phases during the series development and to different levels of detailedness of virtual testing approaches.