OpenRaiser/Intern-Atlas huggingface dataset:
Beamforming for MISO Interference Channels with QoS and RF Energy Transfer
Venue: arXiv cs.IT 2013
Year: 2013

We consider a multiuser multiple-input single-output interference channel where the receivers are characterized by both quality-of-service (QoS) and radio-frequency (RF) energy harvesting (EH) constraints. We consider the power splitting RF-EH technique where each receiver divides the received signal into two parts a) for information decoding and b) for battery charging. The minimum required power that supports both the QoS and the RF-EH constraints is formulated as an optimization problem that incorporates the transmitted power and the beamforming design at each transmitter as well as the power splitting ratio at each receiver. We consider both the cases of fixed beamforming and when the beamforming design is incorporated into the optimization problem. For fixed beamforming we study three standard beamforming schemes, the zero-forcing (ZF), the regularized zero-forcing (RZF) and the maximum ratio transmission (MRT); a hybrid scheme, MRT-ZF, comprised of a linear combination of MRT and ZF beamforming is also examined. The optimal solution for ZF beamforming is derived in closed-form, while optimization algorithms based on second-order cone programming are developed for MRT, RZF and MRT-ZF beamforming to solve the problem. In addition, the joint-optimization of beamforming and power allocation is studied using semidefinite programming (SDP) with the aid of rank relaxation.
Spatially-Adaptive Reconstruction in Computed Tomography using Neural Networks
Venue: arXiv cs.CV 2013
Year: 2013

We propose a supervised machine learning approach for boosting existing signal and image recovery methods and demonstrate its efficacy on example of image reconstruction in computed tomography. Our technique is based on a local nonlinear fusion of several image estimates, all obtained by applying a chosen reconstruction algorithm with different values of its control parameters. Usually such output images have different bias/variance trade-off. The fusion of the images is performed by feed-forward neural network trained on a set of known examples. Numerical experiments show an improvement in reconstruction quality relatively to existing direct and iterative reconstruction methods.
Stop_times based Routing Protocol for VANET
Venue: arXiv cs.NI 2013
Year: 2013

Vehicular Ad hoc Network (VANET) is a special class of Mobile Ad hoc Network (MANET) where vehicles are considered as MANET nodes with wireless links. The key difference of VANET and MANET is the special mobility pattern and rapidly changeable topology. There has been significant interest in improving safety and traffic efficiency using VANET. The design of routing protocols in VANET is important and necessary issue for support the smart ITS. Existing routing protocols of MANET are not suitable for VANET. AOMDV is the most important on demand multipath routing protocol. This paper proposes SSD-AOMDV as VANET routing protocol. SSD-AOMDV improves AOMDV to suit VANET characteristics. SSD-AOMDV adds the mobility parameters: Stop_times, Speed and Direction to hop count as new AOMDV routing metric to select next hop during the route discovery phase. Stop_times metric is added to simulate buses mobility pattern and traffic lights at intersections. Simulation results show that SSD-AOMDV achieves better performance compared to AOMDV.
In-Network Caching vs. Redundancy Elimination
Venue: arXiv cs.NI 2013
Year: 2013

Network-level Redundancy Elimination (RE) techniques have been proposed to reduce the amount of traffic in the Internet. and the costs of the WAN access in the Internet. RE middleboxes are usually placed in the network access gateways and strip off the repeated data from the packets. More recently, generic network-level caching architectures have been proposed as alternative to reduce the redundant data traffic in the network, presenting benefits and drawbacks compared to RE. In this paper, we compare a generic in-network caching architecture against state-of-the-art redundancy elimination (RE) solutions on real network topologies, presenting the advantages of each technique. Our results show that in-network caching architectures outperform state-of-the-art RE solutions across a wide range of traffic characteristics and parameters.
Optimum Tag Reading Efficiency of Multi-Packet Reception Capable RFID Readers
Venue: arXiv cs.NI 2013
Year: 2013

Maximizing the tag reading rate of a reader is one of the most important design objectives in RFID systems as the tag reading rate is inversely proportional to the time required to completely read all the tags within the reader's radio field. To this end, numerous techniques have been independently suggested so far and they can be broadly categorized into pure advancements in the link-layer tag anti-collision protocols and pure advancements in the physical-layer RF transmission/reception model. In this paper, we show by rigorous mathematical analysis and Monte Carlo simulations that how such two independent approaches can be coupled to attain the optimum tag reading efficiency in a RFID system considering a Dynamic Frame Slotted Aloha based link layer anti-collision protocol at tags and a Multi-Packet Reception capable RF reception model at the reader.
A Proposal for the Characterization of Multi-Dimensional Inter-relationships of RDF Graphs Based on Set Theoretic Approach
Venue: arXiv cs.DB 2013
Year: 2013

In this paper a Set Theoretic approach has been reported for analyzing inter-relationship between any numbers of RDF Graphs. An RDF Graph represents triples in Resource Description Format of semantic web. So the identification and characterization of criteria for inter-relationship of RDF Graphs shows a new road in semantic search. Using set theoretic approach, a sound framing criteria can be designed that examine whether two RDF Graphs are related and if yes, how these relationships could be described with formal set theory. Along with this, by introducing RDF Schema, the inter-relationship status is refined into n-dimensional induced relationships.
Tracking Data-Flow with Open Closure Types
Venue: arXiv cs.PL 2013
Year: 2013

Type systems hide data that is captured by function closures in function types. In most cases this is a beneficial design that favors simplicity and compositionality. However, some applications require explicit information about the data that is captured in closures. This paper introduces open closure types, that is, function types that are decorated with type contexts. They are used to track data-flow from the environment into the function closure. A simply-typed lambda calculus is used to study the properties of the type theory of open closure types. A distinctive feature of this type theory is that an open closure type of a function can vary in different type contexts. To present an application of the type theory, it is shown that a type derivation establishes a simple non-interference property in the sense of information-flow theory. A publicly available prototype implementation of the system can be used to experiment with type derivations for example programs.
Top-k Query Answering in Datalog+/- Ontologies under Subjective Reports (Technical Report)
Venue: arXiv cs.AI 2013
Year: 2013

The use of preferences in query answering, both in traditional databases and in ontology-based data access, has recently received much attention, due to its many real-world applications. In this paper, we tackle the problem of top-k query answering in Datalog+/- ontologies subject to the querying user's preferences and a collection of (subjective) reports of other users. Here, each report consists of scores for a list of features, its author's preferences among the features, as well as other information. Theses pieces of information of every report are then combined, along with the querying user's preferences and his/her trust into each report, to rank the query results. We present two alternative such rankings, along with algorithms for top-k (atomic) query answering under these rankings. We also show that, under suitable assumptions, these algorithms run in polynomial time in the data complexity. We finally present more general reports, which are associated with sets of atoms rather than single atoms.
Effects of Cooperation Policy and Network Topology on Performance of In-Network Caching
Venue: arXiv cs.NI 2013
Year: 2013

We model the cooperation policy with only two parameters -- search radius $r$ and number of copies in the network $N_{copy}$. These two parameters represent the range of cooperation and tolerance of duplicates. We show how cooperation policy impacts content distribution, and further illustrate the relation between content popularity and topological properties. Our work leads many implications on how to take advantage of topological properties in in-network caching strategy design.
A Typology of Collaboration Platform Users
Venue: arXiv cs.CY 2013
Year: 2013

In this paper we present a review of the existing typologies of Internet service users. We zoom in on social networking services including blogs and crowdsourcing websites. Based on the results of the analysis of the considered typologies obtained by means of FCA we developed a new user typology of a certain class of Internet services, namely a collaboration innovation platform. Cluster analysis of data extracted from the collaboration platform Witology was used to divide more than 500 participants into six groups based on three activity indicators: idea generation, commenting, and evaluation (assigning marks) The obtained groups and their percentages appear to follow the "90 - 9 - 1" rule.
Empowering Evolving Social Network Users with Privacy Rights
Venue: arXiv cs.DB 2013
Year: 2013

Considerable concerns exist over privacy on social networks, and huge debates persist about how to extend the artifacts users need to effectively protect their rights to privacy. While many interesting ideas have been proposed, no single approach appears to be comprehensive enough to be the front runner. In this paper, we propose a comprehensive and novel reference conceptual model for privacy in constantly evolving social networks and establish its novelty by briefly contrasting it with contemporary research. We also present the contours of a possible query language that we can develop with desirable features in light of the reference model, and refer to a new query language, {\em PiQL}, developed on the basis of this model that aims to support user driven privacy policy authoring and enforcement. The strength of our model is that such extensions are now possible by developing appropriate linguistic constructs as part of query languages such as SQL, as demonstrated in PiQL.
Five Disruptive Technology Directions for 5G
Venue: arXiv cs.NI 2013
Year: 2013

New research directions will lead to fundamental changes in the design of future 5th generation (5G) cellular networks. This paper describes five technologies that could lead to both architectural and component disruptive design changes: device-centric architectures, millimeter Wave, Massive-MIMO, smarter devices, and native support to machine-2-machine. The key ideas for each technology are described, along with their potential impact on 5G and the research challenges that remain.
Evolutionary Dynamics of Information Diffusion over Social Networks
Venue: arXiv cs.SI 2013
Year: 2013

Current social networks are of extremely large-scale generating tremendous information flows at every moment. How information diffuse over social networks has attracted much attention from both industry and academics. Most of the existing works on information diffusion analysis are based on machine learning methods focusing on social network structure analysis and empirical data mining. However, the dynamics of information diffusion, which are heavily influenced by network users' decisions, actions and their socio-economic interactions, is generally ignored by most of existing works. In this paper, we propose an evolutionary game theoretic framework to model the dynamic information diffusion process in social networks. Specifically, we derive the information diffusion dynamics in complete networks, uniform degree and non-uniform degree networks, with the highlight of two special networks, Erdős-Rényi random network and the Barabási-Albert scale-free network. We find that the dynamics of information diffusion over these three kinds of networks are scale-free and the same with each other when the network scale is sufficiently large. To verify our theoretical analysis, we perform simulations for the information diffusion over synthetic networks and real-world Facebook networks. Moreover, we also conduct experiment on Twitter hashtags dataset, which shows that the proposed game theoretic model can well fit and predict the information diffusion over real social networks.
Polar Codes: Graph Representation and Duality
Venue: arXiv cs.IT 2013
Year: 2013

In this paper, we present an iterative construction of a polar code and develop properties of the dual of a polar code. Based on this approach, belief propagation of a polar code can be presented in the context of low-density parity check codes.
Formal Model of Web Service Composition: An Actor-Based Approach to Unifying Orchestration and Choreography
Venue: arXiv cs.SE 2013
Year: 2013

Web Service Composition creates new composite Web Services from the collection of existing ones to be composed further and embodies the added values and potential usages of Web Services. Web Service Composition includes two aspects: Web Service orchestration denoting a workflow-like composition pattern and Web Service choreography which represents an aggregate composition pattern. There were only a few works which give orchestration and choreography a relationship. In this paper, we introduce an architecture of Web Service Composition runtime which establishes a natural relationship between orchestration and choreography through a deep analysis of the two ones. Then we use an actor-based approach to design a language called AB-WSCL to support such an architecture. To give AB-WSCL a firmly theoretic foundation, we establish the formal semantics of AB-WSCL based on concurrent rewriting theory for actors. Conclusions that well defined relationships exist among the components of AB-WSCL using a notation of Compositionality is drawn based on semantics analysis. Our works can be bases of a modeling language, simulation tools, verification tools of Web Service Composition at design time, and also a Web Service Composition runtime with correctness analysis support itself.
Software Defined Radio Implementation of Signaling Splitting in Hyper-Cellular Network
Venue: arXiv cs.NI 2013
Year: 2013

This paper presents the design and implementation of signaling splitting scheme in hyper-cellular network on a software defined radio platform. Hyper-cellular network is a novel architecture of future mobile communication systems in which signaling and data are decoupled at the air interface to mitigate the signaling overhead and allow energy efficient operation of base stations. On an open source software defined radio platform, OpenBTS, we investigate the feasibility of signaling splitting for GSM protocol and implement a novel system which can prove the proposed concept. Standard GSM handsets can camp on the network with the help of signaling base station, and data base station will be appointed to handle phone calls on demand. Our work initiates the systematic approach to study hyper-cellular concept in real wireless environment with both software and hardware implementations.
Use of the C4.5 machine learning algorithm to test a clinical guideline-based decision support system
Venue: arXiv cs.AI 2013
Year: 2013

Well-designed medical decision support system (DSS) have been shown to improve health care quality. However, before they can be used in real clinical situations, these systems must be extensively tested, to ensure that they conform to the clinical guidelines (CG) on which they are based. Existing methods cannot be used for the systematic testing of all possible test cases. We describe here a new exhaustive dynamic verification method. In this method, the DSS is considered to be a black box, and the Quinlan C4.5 algorithm is used to build a decision tree from an exhaustive set of DSS input vectors and outputs. This method was successfully used for the testing of a medical DSS relating to chronic diseases: the ASTI critiquing module for type 2 diabetes.
Parallel Deferred Update Replication
Venue: arXiv cs.DC 2013
Year: 2013

Deferred update replication (DUR) is an established approach to implementing highly efficient and available storage. While the throughput of read-only transactions scales linearly with the number of deployed replicas in DUR, the throughput of update transactions experiences limited improvements as replicas are added. This paper presents Parallel Deferred Update Replication (P-DUR), a variation of classical DUR that scales both read-only and update transactions with the number of cores available in a replica. In addition to introducing the new approach, we describe its full implementation and compare its performance to classical DUR and to Berkeley DB, a well-known standalone database.
Template-Based Active Contours
Venue: arXiv cs.CV 2013
Year: 2013

We develop a generalized active contour formalism for image segmentation based on shape templates. The shape template is subjected to a restricted affine transformation (RAT) in order to segment the object of interest. RAT allows for translation, rotation, and scaling, which give a total of five degrees of freedom. The proposed active contour comprises an inner and outer contour pair, which are closed and concentric. The active contour energy is a contrast function defined based on the intensities of pixels that lie inside the inner contour and those that lie in the annulus between the inner and outer contours. We show that the contrast energy functional is optimal under certain conditions. The optimal RAT parameters are computed by maximizing the contrast function using a gradient descent optimizer. We show that the calculations are made efficient through use of Green's theorem. The proposed formalism is capable of handling a variety of shapes because for a chosen template, optimization is carried with respect to the RAT parameters only. The proposed formalism is validated on multiple images to show robustness to Gaussian and Poisson noise, to initialization, and to partial loss of structure in the object to be segmented.
The Relevance of Assumptions and Context Factors for the Integration of Inspections and Testing
Venue: arXiv cs.SE 2013
Year: 2013

Integrating inspection processes with testing processes promises to deliver several benefits, including reduced effort for quality assurance or higher defect detection rates. Systematic integration of these processes requires knowledge regarding the relationships between these processes, especially regarding the relationship between inspection defects and test defects. Such knowledge is typically context-dependent and needs to be gained analytically or empirically. If such kind of knowledge is not available, assumptions need to be made for a specific context. This article describes the relevance of assumptions and context factors for integrating inspection and testing processes and provides mechanisms for deriving assumptions in a systematic manner.
FRANTIC: A Fast Reference-based Algorithm for Network Tomography via Compressive Sensing
Venue: arXiv cs.NI 2013
Year: 2013

We study the problem of link and node delay estimation in undirected networks when at most k out of n links or nodes in the network are congested. Our approach relies on end-to-end measurements of path delays across pre-specified paths in the network. We present a class of algorithms that we call FRANTIC. The FRANTIC algorithms are motivated by compressive sensing; however, unlike traditional compressive sensing, the measurement design here is constrained by the network topology and the matrix entries are constrained to be positive integers. A key component of our design is a new compressive sensing algorithm SHO-FA-INT that is related to the prior SHO-FA algorithm for compressive sensing, but unlike SHO-FA, the matrix entries here are drawn from the set of integers {0, 1, ..., M}. We show that O(k log n /log M) measurements suffice both for SHO-FA-INT and FRANTIC. Further, we show that the computational complexity of decoding is also O(k log n/log M) for each of these algorithms. Finally, we look at efficient constructions of the measurement operations through Steiner Trees.
Combining Simulated Annealing and Monte Carlo Tree Search for Expression Simplification
Venue: arXiv cs.AI 2013
Year: 2013

In many applications of computer algebra large expressions must be simplified to make repeated numerical evaluations tractable. Previous works presented heuristically guided improvements, e.g., for Horner schemes. The remaining expression is then further reduced by common subexpression elimination. A recent approach successfully applied a relatively new algorithm, Monte Carlo Tree Search (MCTS) with UCT as the selection criterion, to find better variable orderings. Yet, this approach is fit for further improvements since it is sensitive to the so-called exploration-exploitation constant $C_p$ and the number of tree updates $N$. In this paper we propose a new selection criterion called Simulated Annealing UCT (SA-UCT) that has a dynamic exploration-exploitation parameter, which decreases with the iteration number $i$ and thus reduces the importance of exploration over time. First, we provide an intuitive explanation in terms of the exploration-exploitation behavior of the algorithm. Then, we test our algorithm on three large expressions of different origins. We observe that SA-UCT widens the interval of good initial values $C_p$ where best results are achieved. The improvement is large (more than a tenfold) and facilitates the selection of an appropriate $C_p$.
Linear transformation distance for bichromatic matchings
Venue: arXiv cs.CG 2013
Year: 2013

Let $P=B\cup R$ be a set of $2n$ points in general position, where $B$ is a set of $n$ blue points and $R$ a set of $n$ red points. A \emph{$BR$-matching} is a plane geometric perfect matching on $P$ such that each edge has one red endpoint and one blue endpoint. Two $BR$-matchings are compatible if their union is also plane. The \emph{transformation graph of $BR$-matchings} contains one node for each $BR$-matching and an edge joining two such nodes if and only if the corresponding two $BR$-matchings are compatible. In SoCG 2013 it has been shown by Aloupis, Barba, Langerman, and Souvaine that this transformation graph is always connected, but its diameter remained an open question. In this paper we provide an alternative proof for the connectivity of the transformation graph and prove an upper bound of $2n$ for its diameter, which is asymptotically tight.