OpenRaiser/Intern-Atlas huggingface dataset:
Efficient Object Detection for High Resolution Images
Venue: arXiv cs.CV 2015
Year: 2015

Efficient generation of high-quality object proposals is an essential step in state-of-the-art object detection systems based on deep convolutional neural networks (DCNN) features. Current object proposal algorithms are computationally inefficient in processing high resolution images containing small objects, which makes them the bottleneck in object detection systems. In this paper we present effective methods to detect objects for high resolution images. We combine two complementary strategies. The first approach is to predict bounding boxes based on adjacent visual features. The second approach uses high level image features to guide a two-step search process that adaptively focuses on regions that are likely to contain small objects. We extract features required for the two strategies by utilizing a pre-trained DCNN model known as AlexNet. We demonstrate the effectiveness of our algorithm by showing its performance on a high-resolution image subset of the SUN 2012 object detection dataset.
5G Ultra-Reliable Vehicular Communication
Venue: arXiv cs.IT 2015
Year: 2015

Applications enabled by Cooperative Intelligent Transport Systems (C-ITS) represent a major step towards making the road transport system safer and more efficient (green), and thus suited for a sustainable future. Wireless communication between vehicles and road infrastructure is an enabler for high-performance C-ITS applications. State-of-the-art communication systems for supporting low-latency C-ITS applications are based on IEEE 802.11 medium access control (MAC) and physical (PHY) layers. In this paper, we argue that a well-designed 5G system can complement or even replace these systems. We will review the C-ITS application requirements and explain how these are well aligned with the foreseen generic 5G service of ultra-reliable machine-type communication (uMTC). Key technology components suitable for constructing the uMTC service are identified: reliable service composition (RSC) and device-to-device (D2D) links for all-to-all broadcast communication, operational at high mobility and with varying degree of network assistance. Important problems for future studies, including radio-resource management, medium access control, and physical layer challenges, are discussed.
Cooperative spectrum sensing schemes with partial statistics knowledge
Venue: arXiv cs.IT 2015
Year: 2015

In this letter, we analyze the problem of detecting spectrum holes in cognitive radio systems. We consider that a group of unlicensed users can sense the radio signal energy, perform some simple processing and transmit the result to a central entity, where the decision about the presence or not of licensed users is made. We show that the proposed cooperative schemes present good performances even without any knowledge about the measurements statistics in the unlicensed users and with only partial knowledge of them in the central entity.
Distributed Energy Spectral Efficiency Optimization for Partial/Full Interference Alignment in Multi-User Multi-Relay Multi-Cell MIMO Systems
Venue: arXiv cs.IT 2015
Year: 2015

The energy spectral efficiency maximization (ESEM) problem of a multi-user, multi-relay, multi-cell system is considered, where all the network nodes are equipped with multi-antenna transceivers. To deal with the potentially excessive interference originating from a plethora of geographically distributed transmission sources, a pair of transmission protocols based on interference alignment (IA) are conceived. The first, termed the full-IA, avoids all intra-cell interference (ICI) and other-cell interference by finding the perfect interference-nulling receive beamforming matrices (RxBFMs). The second protocol, termed partial-IA, only attempts to null the ICI. Employing the RxBFMs computed by either of these protocols mathematically decomposes the channel into a multiplicity of non-interfering multiple-input--single-output channels, which we term as spatial multiplexing components (SMCs). The problem of finding the optimal SMCs as well as their power control variables for the ESEM problem considered is formally defined and converted into a convex optimization form with carefully selected variable relaxations and transformations. Thus, the optimal SMCs and power control variables can be distributively computed using both the classic dual decomposition and subgradient methods. Our results indicate that indeed, the ESEM algorithm performs better than the baseline equal power allocation algorithm in terms of its ESE. Furthermore, surprisingly the partial-IA outperforms the full-IA in all cases considered, which is because the partial-IA is less restrictive in terms of the number of available transmit dimensions at the transmitters. Given the typical cell sizes considered in this paper, the path-loss sufficiently attenuates the majority of the interference, and thus the full-IA over-compensates, when trying to avoid all possible sources of interference.
Quantifying Emergent Behavior of Autonomous Robots
Venue: arXiv cs.IT 2015
Year: 2015

Quantifying behaviors of robots which were generated autonomously from task-independent objective functions is an important prerequisite for objective comparisons of algorithms and movements of animals. The temporal sequence of such a behavior can be considered as a time series and hence complexity measures developed for time series are natural candidates for its quantification. The predictive information and the excess entropy are such complexity measures. They measure the amount of information the past contains about the future and thus quantify the nonrandom structure in the temporal sequence. However, when using these measures for systems with continuous states one has to deal with the fact that their values will depend on the resolution with which the systems states are observed. For deterministic systems both measures will diverge with increasing resolution. We therefore propose a new decomposition of the excess entropy in resolution dependent and resolution independent parts and discuss how they depend on the dimensionality of the dynamics, correlations and the noise level. For the practical estimation we propose to use estimates based on the correlation integral instead of the direct estimation of the mutual information using the algorithm by Kraskov et al. (2004) which is based on next neighbor statistics because the latter allows less control of the scale dependencies. Using our algorithm we are able to show how autonomous learning generates behavior of increasing complexity with increasing learning duration.
Simultaneous Feedback Vertex Set: A Parameterized Perspective
Venue: arXiv cs.DS 2015
Year: 2015

Given a family of graphs $\mathcal{F}$, a graph $G$, and a positive integer $k$, the $\mathcal{F}$-Deletion problem asks whether we can delete at most $k$ vertices from $G$ to obtain a graph in $\mathcal{F}$. $\mathcal{F}$-Deletion generalizes many classical graph problems such as Vertex Cover, Feedback Vertex Set, and Odd Cycle Transversal. A graph $G = (V, \cup_{i=1}^α E_{i})$, where the edge set of $G$ is partitioned into $α$ color classes, is called an $α$-edge-colored graph. A natural extension of the $\mathcal{F}$-Deletion problem to edge-colored graphs is the $α$-Simultaneous $\mathcal{F}$-Deletion problem. In the latter problem, we are given an $α$-edge-colored graph $G$ and the goal is to find a set $S$ of at most $k$ vertices such that each graph $G_i \setminus S$, where $G_i = (V, E_i)$ and $1 \leq i \leq α$, is in $\mathcal{F}$. In this work, we study $α$-Simultaneous $\mathcal{F}$-Deletion for $\mathcal{F}$ being the family of forests. In other words, we focus on the $α$-Simultaneous Feedback Vertex Set ($α$-SimFVS) problem. Algorithmically, we show that, like its classical counterpart, $α$-SimFVS parameterized by $k$ is fixed-parameter tractable (FPT) and admits a polynomial kernel, for any fixed constant $α$. In particular, we give an algorithm running in $2^{O(αk)}n^{O(1)}$ time and a kernel with $O(αk^{3(α+ 1)})$ vertices. The running time of our algorithm implies that $α$-SimFVS is FPT even when $α\in o(\log n)$. We complement this positive result by showing that for $α\in O(\log n)$, where $n$ is the number of vertices in the input graph, $α$-SimFVS becomes W[1]-hard. Our positive results answer one of the open problems posed by Cai and Ye (MFCS 2014).
Splicing Systems from Past to Future: Old and New Challenges
Venue: arXiv cs.FL 2015
Year: 2015

A splicing system is a formal model of a recombinant behaviour of sets of double stranded DNA molecules when acted on by restriction enzymes and ligase. In this survey we will concentrate on a specific behaviour of a type of splicing systems, introduced by Păun and subsequently developed by many researchers in both linear and circular case of splicing definition. In particular, we will present recent results on this topic and how they stimulate new challenging investigations.
DKP-AOM: results for OAEI 2015
Venue: arXiv cs.AI 2015
Year: 2015

In this paper, we present the results obtained by our DKP-AOM system within the OAEI 2015 campaign. DKP-AOM is an ontology merging tool designed to merge heterogeneous ontologies. In OAEI, we have participated with its ontology mapping component which serves as a basic module capable of matching large scale ontologies before their merging. This is our first successful participation in the Conference, OA4QA and Anatomy track of OAEI. DKP-AOM is participating with two versions (DKP-AOM and DKP-AOM_lite), DKP-AOM performs coherence analysis. In OA4QA track, DKPAOM out-performed in the evaluation and generated accurate alignments allowed to answer all the queries of the evaluation. We can also see its competitive results for the conference track in the evaluation initiative among other reputed systems. In the anatomy track, it has produced alignments within an allocated time and appeared in the list of systems which produce coherent results. Finally, we discuss some future work towards the development of DKP-AOM.
Smartphones in Mental Health: Detecting Depressive and Manic Episodes
Venue: arXiv cs.HC 2015
Year: 2015

An observational study with patients diagnosed with bipolar disorder investigates whether data from smartphone sensors can be used to recognize bipolar disorder episodes and detect behavior changes that can signal an onset of an episode using objective data.
Sketching for Simultaneously Sparse and Low-Rank Covariance Matrices
Venue: arXiv cs.IT 2015
Year: 2015

We introduce a technique for estimating a structured covariance matrix from observations of a random vector which have been sketched. Each observed random vector $\boldsymbol{x}_t$ is reduced to a single number by taking its inner product against one of a number of pre-selected vector $\boldsymbol{a}_\ell$. These observations are used to form estimates of linear observations of the covariance matrix $\boldsymbol{\varSigma}$, which is assumed to be simultaneously sparse and low-rank. We show that if the sketching vectors $\boldsymbol{a}_\ell$ have a special structure, then we can use straightforward two-stage algorithm that exploits this structure. We show that the estimate is accurate when the number of sketches is proportional to the maximum of the rank times the number of significant rows/columns of $\boldsymbol{\varSigma}$. Moreover, our algorithm takes direct advantage of the low-rank structure of $\boldsymbol{\varSigma}$ by only manipulating matrices that are far smaller than the original covariance matrix.
Doubled patterns are $3$-avoidable
Venue: arXiv cs.DM 2015
Year: 2015

In combinatorics on words, a word $w$ over an alphabet $Σ$ is said to avoid a pattern $p$ over an alphabet $Δ$ if there is no factor $f$ of $w$ such that $f=h(p)$ where $h:Δ^*\toΣ^*$ is a non-erasing morphism. A pattern $p$ is said to be $k$-avoidable if there exists an infinite word over a $k$-letter alphabet that avoids $p$. A pattern is said to be doubled if no variable occurs only once. Doubled patterns with at most 3 variables and patterns with at least 6 variables are $3$-avoidable. We show that doubled patterns with 4 and 5 variables are also $3$-avoidable.
Encouraging Diversity- and Representation-Awareness in Geographically Centralized Content
Venue: arXiv cs.SI 2015
Year: 2015

In centralized countries, not only population, media and economic power are concentrated, but people give more attention to central locations. While this is not inherently bad, this behavior extends to micro-blogging platforms: central locations get more attention in terms of information flow. In this paper we study the effects of an information filtering algorithm that decentralizes content in such platforms. Particularly, we find that users from non-central locations were not able to identify the geographical diversity on timelines generated by the algorithm, which were diverse by construction. To make users see the inherent diversity, we define a design rationale to approach this problem, focused on an already known visualization technique: treemaps. Using interaction data from an "in the wild" deployment of our proposed system, we find that, even though there are effects of centralization in exploratory user behavior, the treemap was able to make users see the inherent geographical diversity of timelines, and engage with user generated content. With these results in mind, we propose practical actions for micro-blogging platforms to account for the differences and biased behavior induced by centralization.
Towards a general framework for an observation and knowledge based model of occupant behaviour in office buildings
Venue: arXiv cs.AI 2015
Year: 2015

This paper proposes a new general approach based on Bayesian networks to model the human behaviour. This approach represents human behaviour withprobabilistic cause-effect relations based not only on previous works, but also with conditional probabilities coming either from expert knowledge or deduced from observations. The approach has been used in the co-simulation of building physics and human behaviour in order to assess the CO 2 concentration in an office.
A Probabilistic Approach Towards Exact-Repair Regeneration Codes
Venue: arXiv cs.IT 2015
Year: 2015

Regeneration codes with exact-repair property for distributed storage systems is studied in this paper. For exact- repair problem, the achievable points of (α,β) tradeoff match with the outer bound only for minimum storage regenerating (MSR), minimum bandwidth regenerating (MBR), and some specific values of n, k, and d. Such tradeoff is characterized in this work for general (n, k, k), (i.e., k = d) for some range of per-node storage (α) and repair-bandwidth (β). Rather than explicit code construction, achievability of these tradeoff points is shown by proving existence of exact-repair regeneration codes for any (n,k,k). More precisely, it is shown that an (n, k, k) system can be extended by adding a new node, which is randomly picked from some ensemble, and it is proved that, with high probability, the existing nodes together with the newly added one maintain properties of exact-repair regeneration codes. The new achievable region improves upon the existing code constructions. In particular, this result provides a complete tradeoff characterization for an (n,3,3) distributed storage system for any value of n.
The F-snapshot Problem
Venue: arXiv cs.DC 2015
Year: 2015

Aguilera, Gafni and Lamport introduced the signaling problem in [5]. In this problem, two processes numbered 0 and 1 can call two procedures: update and Fscan. A parameter of the problem is a two- variable function $F(x_0,x_1)$. Each process $p_i$ can assign values to variable $x_i$ by calling update(v) with some data value v, and compute the value: $F(x_0,x_1)$ by executing an Fscan procedure. The problem is interesting when the domain of $F$ is infinite and the range of $F$ is finite. In this case, some "access restrictions" are imposed that limit the size of the registers that the Fscan procedure can access. Aguilera et al. provided a non-blocking solution and asked whether a wait-free solution exists. A positive answer can be found in [7]. The natural generalization of the two-process signaling problem to an arbitrary number of processes turns out to yield an interesting generalization of the fundamental snapshot problem, which we call the F-snapshot problem. In this problem $n$ processes can write values to an $n$-segment array (each process to its own segment), and can read and obtain the value of an n-variable function $F$ on the array of segments. In case that the range of $F$ is finite, it is required that only bounded registers are accessed when the processes apply the function $F$ to the array, although the data values written to the segments may be taken from an infinite set. We provide here an affirmative answer to the question of Aguilera et al. for an arbitrary number of processes. Our solution employs only single-writer atomic registers, and its time complexity is $O(n \log n)$, which is also the time complexity of the fastest snapshot algorithm that uses only single-writer registers.
Empirical Analysis of Sampling Based Estimators for Evaluating RBMs
Venue: arXiv cs.LG 2015
Year: 2015

The Restricted Boltzmann Machines (RBM) can be used either as classifiers or as generative models. The quality of the generative RBM is measured through the average log-likelihood on test data. Due to the high computational complexity of evaluating the partition function, exact calculation of test log-likelihood is very difficult. In recent years some estimation methods are suggested for approximate computation of test log-likelihood. In this paper we present an empirical comparison of the main estimation methods, namely, the AIS algorithm for estimating the partition function, the CSL method for directly estimating the log-likelihood, and the RAISE algorithm that combines these two ideas. We use the MNIST data set to learn the RBM and then compare these methods for estimating the test log-likelihood.
Data Transmission with Reduced Delay for Distributed Acoustic Sensors
Venue: arXiv cs.DC 2015
Year: 2015

This paper proposes a channel access control scheme fit to dense acoustic sensor nodes in a sensor network. In the considered scenario, multiple acoustic sensor nodes within communication range of a cluster head are grouped into clusters. Acoustic sensor nodes in a cluster detect acoustic signals and convert them into electric signals (packets). Detection by acoustic sensors can be executed periodically or randomly and random detection by acoustic sensors is event driven. As a result, each acoustic sensor generates their packets (50bytes each) periodically or randomly over short time intervals (400ms~4seconds) and transmits directly to a cluster head (coordinator node). Our approach proposes to use a slotted carrier sense multiple access. All acoustic sensor nodes in a cluster are allocated to time slots and the number of allocated sensor nodes to each time slot is uniform. All sensor nodes allocated to a time slot listen for packet transmission from the beginning of the time slot for a duration proportional to their priority. The first node that detect the channel to be free for its whole window is allowed to transmit. The order of packet transmissions with the acoustic sensor nodes in the time slot is autonomously adjusted according to the history of packet transmissions in the time slot. In simulations, performances of the proposed scheme are demonstrated by the comparisons with other low rate wireless channel access schemes.
Born In Bradford Mobile Application
Venue: arXiv cs.CY 2015
Year: 2015

The Born In Bradford mobile application is an Android mobile application and a working prototype that enables interaction with a sample cohort of the Born in Bradford study. It provides an interface and visualization for several surveys participated in by mothers and their children. This data is stored in the Born In Bradford database. A subset of this data is provided for mothers and children. The mobile application provides a way to engage the mothers and promote their consistency in participating in subsequent surveys. It has been designed to allow selected mothers to participate in the visualization of their babies data. Samsung mobile phones have been provided with the application loaded on the phone to limit and control its use and access to data. Mothers login to interact with the data. This includes the ability to compare children data through infographics and graphs and comparing their children data with the average child. This comparison is done at different stages of the children ages as provided in the dataset.
Security-aware selection of Web Services for Reliable Composition
Venue: arXiv cs.DC 2015
Year: 2015

Dependability is an important characteristic that a trustworthy computer system should have. It is a measure of Availability, Reliability, Maintainability, Safety and Security. The focus of our research is on security of web services. Web services enable the composition of independent services with complementary functionalities to produce value-added services, which allows organizations to implement their core business only and outsource other service components over the Internet, either pre-selected or on-the-fly. The selected third party web services may have security vulnerabilities. Vulnerable web services are of limited practical use. We propose to use an intrusion-tolerant composite web service for each functionality that should be fulfilled by a third party web service. The third party services employed in this approach should be selected based on their security vulnerabilities in addition to their performance. The security vulnerabilities of the third party services are assessed using a penetration testing tool. In this paper we present our preliminary research work.
On Contact Graphs with Cubes and Proportional Boxes
Venue: arXiv cs.CG 2015
Year: 2015

We study two variants of the problem of contact representation of planar graphs with axis-aligned boxes. In a cube-contact representation we realize each vertex with a cube, while in a proportional box-contact representation each vertex is an axis-aligned box with a prespecified volume. We present algorithms for constructing cube-contact representation and proportional box-contact representation for several classes of planar graphs.
Applications of Polymatroid Theory to Distributed Storage Systems
Venue: arXiv cs.IT 2015
Year: 2015

In this paper, a link between polymatroid theory and locally repairable codes (LRCs) is established. The codes considered here are completely general in that they are subsets of $A^n$, where $A$ is an arbitrary finite set. Three classes of LRCs are considered, both with and without availability, and for both information-symbol and all-symbol locality. The parameters and classes of LRCs are generalized to polymatroids, and a general- ized Singelton bound on the parameters for these three classes of polymatroids and LRCs is given. This result generalizes the earlier Singleton-type bounds given for LRCs. Codes achieving these bounds are coined perfect, as opposed to the more common term optimal used earlier, since they might not always exist. Finally, new constructions of perfect linear LRCs are derived from gammoids, which are a special class of matroids. Matroids, for their part, form a subclass of polymatroids and have proven useful in analyzing and constructing linear LRCs.