OpenRaiser/Intern-Atlas huggingface dataset:
A proposal for a Chinese keyboard for cellphones, smartphones, ipads and tablets
Venue: arXiv cs.HC 2013
Year: 2013

In this paper, we investigate the possibility to use two tilings of the hyperbolic plane as basic frame for devising a way to input texts in Chinese characters into messages of cellphones, smartphones, ipads and tablets.
Matrix Completion in Colocated MIMO Radar: Recoverability, Bounds & Theoretical Guarantees
Venue: arXiv cs.IT 2013
Year: 2013

It was recently shown that low rank matrix completion theory can be employed for designing new sampling schemes in the context of MIMO radars, which can lead to the reduction of the high volume of data typically required for accurate target detection and estimation. Employing random samplers at each reception antenna, a partially observed version of the received data matrix is formulated at the fusion center, which, under certain conditions, can be recovered using convex optimization. This paper presents the theoretical analysis regarding the performance of matrix completion in colocated MIMO radar systems, exploiting the particular structure of the data matrix. Both Uniform Linear Arrays (ULAs) and arbitrary 2-dimensional arrays are considered for transmission and reception. Especially for the ULA case, under some mild assumptions on the directions of arrival of the targets, it is explicitly shown that the coherence of the data matrix is both asymptotically and approximately optimal with respect to the number of antennas of the arrays involved and further, the data matrix is recoverable using a subset of its entries with minimal cardinality. Sufficient conditions guaranteeing low matrix coherence and consequently satisfactory matrix completion performance are also presented, including the arbitrary 2-dimensional array case.
On the Impossibility of Dimension Reduction for Doubling Subsets of $\ell_p$, $p>2$
Venue: arXiv cs.CG 2013
Year: 2013

A major open problem in the field of metric embedding is the existence of dimension reduction for $n$-point subsets of Euclidean space, such that both distortion and dimension depend only on the {\em doubling constant} of the pointset, and not on its cardinality. In this paper, we negate this possibility for $\ell_p$ spaces with $p>2$. In particular, we introduce an $n$-point subset of $\ell_p$ with doubling constant O(1), and demonstrate that any embedding of the set into $\ell_p^d$ with distortion $D$ must have $D\geΩ\left(\left(\frac{c\log n}{d}\right)^{\frac{1}{2}-\frac{1}{p}}\right)$.
A hybrid evolutionary algorithm with importance sampling for multi-dimensional optimization
Venue: arXiv cs.NE 2013
Year: 2013

A hybrid evolutionary algorithm with importance sampling method is proposed for multi-dimensional optimization problems in this paper. In order to make use of the information provided in the search process, a set of visited solutions is selected to give scores for intervals in each dimension, and they are updated as algorithm proceeds. Those intervals with higher scores are regarded as good intervals, which are used to estimate the joint distribution of optimal solutions through an interaction between the pool of good genetics, which are the individuals with smaller fitness values. And the sampling probabilities for good genetics are determined through an interaction between those estimated good intervals. It is a cross validation mechanism which determines the sampling probabilities for good intervals and genetics, and the resulted probabilities are used to design crossover, mutation and other stochastic operators with importance sampling method. As the selection of genetics and intervals is not directly dependent on the values of fitness, the resulted offsprings may avoid the trap of local optima. And a purely random EA is also combined into the proposed algorithm to maintain the diversity of population. 30 benchmark test functions are used to evaluate the performance of the proposed algorithm, and it is found that the proposed hybrid algorithm is an efficient algorithm for multi-dimensional optimization problems considered in this paper.
Suspicious Object Recognition Method in Video Stream Based on Visual Attention
Venue: arXiv cs.CV 2013
Year: 2013

We propose a state of the art method for intelligent object recognition and video surveillance based on human visual attention. Bottom up and top down attention are applied respectively in the process of acquiring interested object(saliency map) and object recognition. The revision of 4 channel PFT method is proposed for bottom up attention and enhances the speed and accuracy. Inhibit of return (IOR) is applied in judging the sequence of saliency object pop out. Euclidean distance of color distribution, object center coordinates and speed are considered in judging whether the target is match and suspicious. The extensive tests on videos and images show that our method in video analysis has high accuracy and fast speed compared with traditional method. The method can be applied into many fields such as video surveillance and security.
Multi-Channel Deficit Round-Robin Scheduling for Hybrid TDM/WDM Optical Networks
Venue: arXiv cs.NI 2013
Year: 2013

In this paper we propose and investigate the performance of a multi-channel scheduling algorithm based on the well-known deficit round-robin (DRR), which we call multi-channel DRR (MCDRR). We extend the original DRR to the case of multiple channels with tunable transmitters and fixed receivers to provide efficient fair queueing in hybrid time division multiplexing (TDM)/wavelength division multiplexing (WDM) optical networks. We take into account the availability of channels and tunable transmitters in extending the DRR and allow the overlap of `rounds' in scheduling to efficiently utilize channels and tunable transmitters. Simulation results show that the proposed MCDRR can provide nearly perfect fairness with ill-behaved flows for different sets of conditions for interframe times and frame sizes in hybrid TDM/WDM optical networks with tunable transmitters and fixed receivers.
Measuring the Directional Distance Between Fuzzy Sets
Venue: arXiv cs.AI 2013
Year: 2013

The measure of distance between two fuzzy sets is a fundamental tool within fuzzy set theory. However, current distance measures within the literature do not account for the direction of change between fuzzy sets; a useful concept in a variety of applications, such as Computing With Words. In this paper, we highlight this utility and introduce a distance measure which takes the direction between sets into account. We provide details of its application for normal and non-normal, as well as convex and non-convex fuzzy sets. We demonstrate the new distance measure using real data from the MovieLens dataset and establish the benefits of measuring the direction between fuzzy sets.
Policy Specification in Role based Access Control on Clouds
Venue: arXiv cs.DC 2013
Year: 2013

Cloud Computing is a set of IT Services that are provided to a customer over a network and these services are delivered by third party provider who owns the infrastructure and reduce the burden at user's end. Nowadays researchers devoted their work access control method to enhance the security on Cloud. RBAC is attractive access model because the number of roles is significantly less hence users can be easily classified according to their roles. The Role-based Access Control (RBAC) model provides efficient way to manage access to information while reducing the cost of security administration and complexity in large networked applications. This paper specify various policies in RBAC on clouds such as migration policy which helps the user to migrate the database schema and roles easily to the Cloud using XML with more security. Restriction policy provide the security enhancement in Role Based Access Model by restricting the number of transaction per user and if the number of transactions will increase the admin will come to know through its monitoring system that unauthorized access has been made and it would be easier to take action against such happening. This paper proposes backup and restoration policy in Role Based Access Model in which if the main cloud is crashed or not working properly then the backup and restoration facility will be available to avoid the lost of important data. In this case chances of loss of data are very less so enhance more security on Cloud Computing.
Cooperative ISP Traffic Shaping Schemes in Broadband Shared Access Networks
Venue: arXiv cs.NI 2013
Year: 2013

Traffic shaping is a mechanism used by Internet Service Providers (ISPs) to limit subscribers' traffic based on their service contracts. This paper investigates the current implementation of traffic shaping based on the token bucket filter (TBF), discusses its advantages and disadvantages, and proposes a cooperative TBF that can improve subscribers' quality of service (QoS)/quality of experience (QoE) without compromising business aspects of the service contract model by proportionally allocating excess bandwidth from inactive subscribers to active ones based on the long-term bandwidths per their service contracts.
On Conditions for Uniqueness in Sparse Phase Retrieval
Venue: arXiv cs.IT 2013
Year: 2013

The phase retrieval problem has a long history and is an important problem in many areas of optics. Theoretical understanding of phase retrieval is still limited and fundamental questions such as uniqueness and stability of the recovered solution are not yet fully understood. This paper provides several additions to the theoretical understanding of sparse phase retrieval. In particular we show that if the measurement ensemble can be chosen freely, as few as 4k-1 phaseless measurements suffice to guarantee uniqueness of a k-sparse M-dimensional real solution. We also prove that 2(k^2-k+1) Fourier magnitude measurements are sufficient under rather general conditions.
Sparse Channel Estimation by Factor Graphs
Venue: arXiv cs.IT 2013
Year: 2013

The problem of estimating a sparse channel, i.e. a channel with a few non-zero taps, appears in various areas of communications. Recently, we have developed an algorithm based on iterative alternating minimization which iteratively detects the location and the value of the taps. This algorithms involves an approximate Maximum A Posteriori (MAP) probability scheme for detection of the location of taps, while a least square method is used for estimating the values at each iteration. In this work, based on the method of factor graphs and message passing algorithms, we will compute an exact solution for the MAP estimation problem. Indeed, we first find a factor graph model of this problem, and then perform the well-known min-sum algorithm on the edges of this graph. Consequently, we will find an exact estimator for the MAP problem that its complexity grows linearly with respect to the channel memory. By substituting this estimator in the mentioned alternating minimization method, we will propose an estimator that will nearly achieve the Cramer-Rao bound of the genie-aided estimation of sparse channels (estimation based on knowing the location of non-zero taps of the channel), while it can perform faster than most of the proposed algorithms in literature.
Shape identification and classification in echolocation
Venue: arXiv cs.NA 2013
Year: 2013

The paper aims at proposing the first shape identification and classification algorithm in echolocation. The approach is based on first extracting geometric features from the reflected waves and then matching them with precomputed ones associated with a dictionary of targets. The construction of such frequency-dependent shape descriptors is based on some important properties of the scattering coefficients and new invariants. The stability and resolution of the proposed identification algorithm with respect to measurement noise and the limited-view aspect are analytically and numerically quantified.
Fixed parameter tractability of crossing minimization of almost-trees
Venue: arXiv cs.CG 2013
Year: 2013

We investigate exact crossing minimization for graphs that differ from trees by a small number of additional edges, for several variants of the crossing minimization problem. In particular, we provide fixed parameter tractable algorithms for the 1-page book crossing number, the 2-page book crossing number, and the minimum number of crossed edges in 1-page and 2-page book drawings.
Spectrum optimization in multi-user multi-carrier systems with iterative convex and nonconvex approximation methods
Venue: arXiv cs.IT 2013
Year: 2013

Several practical multi-user multi-carrier communication systems are characterized by a multi-carrier interference channel system model where the interference is treated as noise. For these systems, spectrum optimization is a promising means to mitigate interference. This however corresponds to a challenging nonconvex optimization problem. Existing iterative convex approximation (ICA) methods consist in solving a series of improving convex approximations and are typically implemented in a per-user iterative approach. However they do not take this typical iterative implementation into account in their design. This paper proposes a novel class of iterative approximation methods that focuses explicitly on the per-user iterative implementation, which allows to relax the problem significantly, dropping joint convexity and even convexity requirements for the approximations. A systematic design framework is proposed to construct instances of this novel class, where several new iterative approximation methods are developed with improved per-user convex and nonconvex approximations that are both tighter and simpler to solve (in closed-form). As a result, these novel methods display a much faster convergence speed and require a significantly lower computational cost. Furthermore, a majority of the proposed methods can tackle the issue of getting stuck in bad locally optimal solutions, and hence improve solution quality compared to existing ICA methods.
Clean-Slate Design of Next-Generation Optical Access
Venue: arXiv cs.NI 2013
Year: 2013

We report the current status of our research on the clean-slate design of next-generation optical access (NGOA). We have been studying candidate architectures with a major focus on their elasticity to user demands, energy efficiency, and support of better Quality of Experience (QoE). One of the major challenges in this study is to establish a comparative analysis framework where we can assess the performances of candidate architectures in an objective and quantifiable way. In this paper we describe our efforts to meet this challenge: (1) the development of a new comparison framework based on integrated QoE and statistical hypothesis testing and (2) the implementation of a virtual test bed capturing important aspects from physical layer to application layer to end-user behaviour governing traffic generation. The comparison framework and the virtual test bed will provide researchers a sound basis and useful tools for comparative analysis in the clean-slate design of NGOA.
Adaptive detection and severity level characterization algorithm for Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS) via oximetry signal analysis
Venue: arXiv cs.DS 2013
Year: 2013

In this paper, an abstract definition and formal specification is presented for the task of adaptive-threshold OSAHS events detection and severity characterization. Specifically, a low-level pseudocode is designed for the algorithm of raw oximetry signal pre-processing, calculation of the 'drop' and 'rise' frames in the related time series, detection of valid apnea/hypopnea events via SpO2 saturation level tracking, as well as calculation of corresponding event rates for OSAHS severity characterization. The designed algorithm can be used as the first module in a machine learning application where these data can be used as inputs or encoded into higher-level statistics (features) for pattern classifiers, in the context of computer-aided or fully automated diagnosis of OSAHS and related pathologies.
Numerical Analysis of Gate Conflict Duration and Passenger Transit Time in Airport
Venue: arXiv cs.OH 2013
Year: 2013

Robustness is as important as efficiency in air transportation. All components in the air traffic system are connected to form an interactive network. So, a disturbance that occurs in one component, for example, a severe delay at an airport, can influence the entire network. Delays are easily propagated between flights through gates, but the propagation can be reduced if gate assignments are robust against stochastic delays. In this paper, we analyze gate delays and suggest an approach that involves assigning gates while making them robust against stochastic delays. We extract an example flight schedule from data source and generate schedules with increased traffic to analyze how the compact flight schedules impact the robustness of gate assignment. Simulation results show that our approach improves the robustness of gate assignment. Particularly, the robust gate assignment reduces average duration of gate conflicts by 96.3% and the number of gate conflicts by 96.7% compared to the baseline assignment. However, the robust gate assignment results in longer transit time for passengers, and a trade-off between the robustness of gate assignment and passenger transit time is presented.
NRC-Canada: Building the State-of-the-Art in Sentiment Analysis of Tweets
Venue: arXiv cs.CL 2013
Year: 2013

In this paper, we describe how we created two state-of-the-art SVM classifiers, one to detect the sentiment of messages such as tweets and SMS (message-level task) and one to detect the sentiment of a term within a submissions stood first in both tasks on tweets, obtaining an F-score of 69.02 in the message-level task and 88.93 in the term-level task. We implemented a variety of surface-form, semantic, and sentiment features. with sentiment-word hashtags, and one from tweets with emoticons. In the message-level task, the lexicon-based features provided a gain of 5 F-score points over all others. Both of our systems can be replicated us available resources.
Computing Lexical Contrast
Venue: arXiv cs.CL 2013
Year: 2013

Knowing the degree of semantic contrast between words has widespread application in natural language processing, including machine translation, information retrieval, and dialogue systems. Manually-created lexicons focus on opposites, such as {\rm hot} and {\rm cold}. Opposites are of many kinds such as antipodals, complementaries, and gradable. However, existing lexicons often do not classify opposites into the different kinds. They also do not explicitly list word pairs that are not opposites but yet have some degree of contrast in meaning, such as {\rm warm} and {\rm cold} or {\rm tropical} and {\rm freezing}. We propose an automatic method to identify contrasting word pairs that is based on the hypothesis that if a pair of words, $A$ and $B$, are contrasting, then there is a pair of opposites, $C$ and $D$, such that $A$ and $C$ are strongly related and $B$ and $D$ are strongly related. (For example, there exists the pair of opposites {\rm hot} and {\rm cold} such that {\rm tropical} is related to {\rm hot,} and {\rm freezing} is related to {\rm cold}.) We will call this the contrast hypothesis. We begin with a large crowdsourcing experiment to determine the amount of human agreement on the concept of oppositeness and its different kinds. In the process, we flesh out key features of different kinds of opposites. We then present an automatic and empirical measure of lexical contrast that relies on the contrast hypothesis, corpus statistics, and the structure of a {\it Roget}-like thesaurus. We show that the proposed measure of lexical contrast obtains high precision and large coverage, outperforming existing methods.
Point values and normalization of two-direction multiwavelets and their derivatives
Venue: arXiv cs.IT 2013
Year: 2013

Two-direction multiscaling functions $\boldsymbolϕ$ and two-direction multiwavelets $\boldsymbolψ$ associated with $\boldsymbolϕ$ are more general and more flexible setting than one-direction multiscaling functions and multiwavelets. In this paper, we investigate how to find and normalize point values and those of derivatives of the two-direction multiscaling functions $\boldsymbolϕ$ and multiwavelets $\boldsymbolψ$. %associated with $\boldsymbolϕ$. For finding point values, we investigate the eigenvalue approach. For normalization, we investigate the normalizing conditions for them by normalizing the zeroth continuous moment of $\boldsymbolϕ$. Examples for illustrating the general theory are given.
Digital breadcrumbs: Detecting urban mobility patterns and transport mode choices from cellphone networks
Venue: arXiv cs.SI 2013
Year: 2013

Many modern and growing cities are facing declines in public transport usage, with few efficient methods to explain why. In this article, we show that urban mobility patterns and transport mode choices can be derived from cellphone call detail records coupled with public transport data recorded from smart cards. Specifically, we present new data mining approaches to determine the spatial and temporal variability of public and private transportation usage and transport mode preferences across Singapore. Our results, which were validated by Singapore's quadriennial Household Interview Travel Survey (HITS), revealed that there are 3.5 (HITS: 3.5 million) million and 4.3 (HITS: 4.4 million) million inter-district passengers by public and private transport, respectively. Along with classifying which transportation connections are weak or underserved, the analysis shows that the mode share of public transport use increases from 38 percent in the morning to 44 percent around mid-day and 52 percent in the evening.
Streamed Graph Drawing and the File Maintenance Problem
Venue: arXiv cs.DS 2013
Year: 2013

In streamed graph drawing, a planar graph, G, is given incrementally as a data stream and a straight-line drawing of G must be updated after each new edge is released. To preserve the mental map, changes to the drawing should be minimized after each update, and Binucci et al.show that exponential area is necessary and sufficient for a number of streamed graph drawings for trees if edges are not allowed to move at all. We show that a number of streamed graph drawings can, in fact, be done with polynomial area, including planar streamed graph drawings of trees, tree-maps, and outerplanar graphs, if we allow for a small number of coordinate movements after each update. Our algorithms involve an interesting connection to a classic algorithmic problem - the file maintenance problem - and we also give new algorithms for this problem in a framework where bulk memory moves are allowed.
Practical Aspects of the Bitcoin System
Venue: arXiv cs.CY 2013
Year: 2013

Digital payment schemes show an ever increasing importance. Out of the countless different schemes available this article focuses on the popular Bitcoin system. The authors provide a description of Bitcoin's unique technological basis and its accompanying ecosystem of users, miners, trading platforms and vendors. Furthermore, this article discusses Bitcoin's currency-like features and the first regulatory actions take in the European Union and in the United States of America.