OpenRaiser/Intern-Atlas huggingface dataset:
Signaling for Decentralized Routing in a Queueing Network
Venue: arXiv cs.SY 2014
Year: 2014

A discrete-time decentralized routing problem in a service system consisting of two service stations and two controllers is investigated. Each controller is affiliated with one station. Each station has an infinite size buffer. Exogenous customer arrivals at each station occur with rate $λ$. Service times at each station have rate $μ$. At any time, a controller can route one of the customers waiting in its own station to the other station. Each controller knows perfectly the queue length in its own station and observes the exogenous arrivals to its own station as well as the arrivals of customers sent from the other station. At the beginning, each controller has a probability mass function (PMF) on the number of customers in the other station. These PMFs are common knowledge between the two controllers. At each time a holding cost is incurred at each station due to the customers waiting at that station. The objective is to determine routing policies for the two controllers that minimize either the total expected holding cost over a finite horizon or the average cost per unit time over an infinite horizon. In this problem there is implicit communication between the two controllers; whenever a controller decides to send or not to send a customer from its own station to the other station it communicates information about its queue length to the other station. This implicit communication through control actions is referred to as signaling in decentralized control. Signaling results in complex communication and decision problems. In spite of the complexity of signaling involved, it is shown that an optimal signaling strategy is described by a threshold policy which depends on the common information between the two controllers; this threshold policy is explicitly determined.
Action Recognition in the Frequency Domain
Venue: arXiv cs.CV 2014
Year: 2014

In this paper, we describe a simple strategy for mitigating variability in temporal data series by shifting focus onto long-term, frequency domain features that are less susceptible to variability. We apply this method to the human action recognition task and demonstrate how working in the frequency domain can yield good recognition features for commonly used optical flow and articulated pose features, which are highly sensitive to small differences in motion, viewpoint, dynamic backgrounds, occlusion and other sources of variability. We show how these frequency-based features can be used in combination with a simple forest classifier to achieve good and robust results on the popular KTH Actions dataset.
Solving the Problem of the K Parameter in the KNN Classifier Using an Ensemble Learning Approach
Venue: arXiv cs.LG 2014
Year: 2014

This paper presents a new solution for choosing the K parameter in the k-nearest neighbor (KNN) algorithm, the solution depending on the idea of ensemble learning, in which a weak KNN classifier is used each time with a different K, starting from one to the square root of the size of the training set. The results of the weak classifiers are combined using the weighted sum rule. The proposed solution was tested and compared to other solutions using a group of experiments in real life problems. The experimental results show that the proposed classifier outperforms the traditional KNN classifier that uses a different number of neighbors, is competitive with other classifiers, and is a promising classifier with strong potential for a wide range of applications.
Implementation of an adaptive energy-efficient MAC protocol in OMNeT++/MiXiM
Venue: arXiv cs.NI 2014
Year: 2014

In recent years, many MAC protocols for wireless sensor networks have been proposed and most of them are evaluated using Matlab simulator and/or network simulators (OMNeT++, NS2, etc). However, most of them have a static behavior and few network simulations are available for adaptive protocols. Specially, in OMNeT++/MiXiM, there are few energy-efficient MAC protocols for WSNs (B-MAC & L-MAC) and no adaptive ones. To this end, the TAD-MAC (Traffic Aware Dynamic MAC) protocol has been simulated in OMNeT++ with the MiXiM framework and implementation details are given in this paper. The simulation results have been used to evaluate the performance of TAD-MAC through comparisons with B-MAC and L-MAC protocols.
Variability of Behaviour in Electricity Load Profile Clustering; Who Does Things at the Same Time Each Day?
Venue: arXiv cs.LG 2014
Year: 2014

UK electricity market changes provide opportunities to alter households' electricity usage patterns for the benefit of the overall electricity network. Work on clustering similar households has concentrated on daily load profiles and the variability in regular household behaviours has not been considered. Those households with most variability in regular activities may be the most receptive to incentives to change timing. Whether using the variability of regular behaviour allows the creation of more consistent groupings of households is investigated and compared with daily load profile clustering. 204 UK households are analysed to find repeating patterns (motifs). Variability in the time of the motif is used as the basis for clustering households. Different clustering algorithms are assessed by the consistency of the results. Findings show that variability of behaviour, using motifs, provides more consistent groupings of households across different clustering algorithms and allows for more efficient targeting of behaviour change interventions.
A Fuzzy Directional Distance Measure
Venue: arXiv cs.AI 2014
Year: 2014

The measure of distance between two fuzzy sets is a fundamental tool within fuzzy set theory, however, distance measures currently within the literature use a crisp value to represent the distance between fuzzy sets. A real valued distance measure is developed into a fuzzy distance measure which better reflects the uncertainty inherent in fuzzy sets and a fuzzy directional distance measure is presented, which accounts for the direction of change between fuzzy sets. A multiplicative version is explored as a full maximal assignment is computationally intractable so an intermediate solution is offered.
Augmented Neural Networks for Modelling Consumer Indebtness
Venue: arXiv cs.CE 2014
Year: 2014

Consumer Debt has risen to be an important problem of modern societies, generating a lot of research in order to understand the nature of consumer indebtness, which so far its modelling has been carried out by statistical models. In this work we show that Computational Intelligence can offer a more holistic approach that is more suitable for the complex relationships an indebtness dataset has and Linear Regression cannot uncover. In particular, as our results show, Neural Networks achieve the best performance in modelling consumer indebtness, especially when they manage to incorporate the significant and experimentally verified results of the Data Mining process in the model, exploiting the flexibility Neural Networks offer in designing their topology. This novel method forms an elaborate framework to model Consumer indebtness that can be extended to any other real world application.
Versatile Land Navigation Using Inertial Sensors and Odometry: Self-calibration, In-motion Alignment and Positioning
Venue: arXiv cs.RO 2014
Year: 2014

Inertial measurement unit (IMU) and odometer have been commonly-used sensors for autonomous land navigation in the global positioning system (GPS)-denied scenarios. This paper systematically proposes a versatile strategy for self-contained land vehicle navigation using the IMU and an odometer. Specifically, the paper proposes a self-calibration and refinement method for IMU/odometer integration that is able to overcome significant variation of the misalignment parameters, which are induced by many inevitable and adverse factors such as load changing, refueling and ambient temperature. An odometer-aided IMU in-motion alignment algorithm is also devised that enables the first-responsive functionality even when the vehicle is running freely. The versatile strategy is successfully demonstrated and verified via long-distance real tests.
Spectral Efficiency of the Cellular Two-Way Relaying with Large Antenna Arrays
Venue: arXiv cs.IT 2014
Year: 2014

This paper considers a multiuser cellular two-way relay network (cTWRN) where multiple users exchange information with a base station (BS) via a relay station (RS). Each user is equipped with a single antenna, while both the BS and the RS are equipped with a very large antenna array. We investigate the performance of the cTWRN with amplify-and-forward (AF) based physical-layer network coding, and derive closed-form expression for the asymptotic spectral efficiency when both the number of antennas at the BS and the RS grow large. It is shown that the noise propagation of the non-regenerative relaying protocol can be greatly suppressed, and the AF relaying scheme can approach the cut-set bound under certain conditions. We also investigate the performance of the AF relaying scheme under two power-scaling cases, and show that the transmit power of the BS and each user can be made inversely proportional to the number of relay antennas while maintaining a given quality-of-service. Numerical results are presented to verify the analytical results.
On the Properties of Neural Machine Translation: Encoder-Decoder Approaches
Venue: arXiv cs.CL 2014
Year: 2014

Neural machine translation is a relatively new approach to statistical machine translation based purely on neural networks. The neural machine translation models often consist of an encoder and a decoder. The encoder extracts a fixed-length representation from a variable-length input sentence, and the decoder generates a correct translation from this representation. In this paper, we focus on analyzing the properties of the neural machine translation using two models; RNN Encoder--Decoder and a newly proposed gated recursive convolutional neural network. We show that the neural machine translation performs relatively well on short sentences without unknown words, but its performance degrades rapidly as the length of the sentence and the number of unknown words increase. Furthermore, we find that the proposed gated recursive convolutional network learns a grammatical structure of a sentence automatically.
Visual Speech Recognition
Venue: arXiv cs.CV 2014
Year: 2014

Lip reading is used to understand or interpret speech without hearing it, a technique especially mastered by people with hearing difficulties. The ability to lip read enables a person with a hearing impairment to communicate with others and to engage in social activities, which otherwise would be difficult. Recent advances in the fields of computer vision, pattern recognition, and signal processing has led to a growing interest in automating this challenging task of lip reading. Indeed, automating the human ability to lip read, a process referred to as visual speech recognition (VSR) (or sometimes speech reading), could open the door for other novel related applications. VSR has received a great deal of attention in the last decade for its potential use in applications such as human-computer interaction (HCI), audio-visual speech recognition (AVSR), speaker recognition, talking heads, sign language recognition and video surveillance. Its main aim is to recognise spoken word(s) by using only the visual signal that is produced during speech. Hence, VSR deals with the visual domain of speech and involves image processing, artificial intelligence, object detection, pattern recognition, statistical modelling, etc.
Overdemodulation for High-Performance Receivers with Low-Resolution ADC
Venue: arXiv cs.IT 2014
Year: 2014

The design of the analog demodulator for receivers with low-resolution analog-to-digital converters (ADC) is investigated. For infinite ADC resolution, demodulation to baseband with M = 2 orthogonal sinusoidal functions (quadrature demodulation) is an optimum design choice. For receive systems which are restricted to ADC with low amplitude resolution we show here that this classical demodulation approach is suboptimal. To this end we analyze the theoretical channel parameter estimation performance based on a simple pessimistic characterization of the Fisher information measure when forming M > 2 analog demodulation channels prior to an ADC with 1-bit amplitude resolution. In order to emphasize that this inside is also true for communication problems, we provide an additional discussion on the behavior of the Shannon information measure under overdemodulation and 1-bit quantization.
Building-in-Briefcase (BiB)
Venue: arXiv cs.CY 2014
Year: 2014

A building's environment has profound influence on occupant comfort and health. Continuous monitoring of building occupancy and environment is essential to fault detection, intelligent control, and building commissioning. Though many solutions for environmental measuring based on wireless sensor networks exist, they are not easily accessible to households and building owners who may lack time or technical expertise needed to set up a system and get quick and detailed overview of environmental conditions. Building-in-Briefcase (BiB) is a portable sensor network platform that is trivially easy to deploy in any building environment. Once the sensors are distributed, the environmental data is collected and communicated to the BiB router via TCP/IP protocol and WiFi technology which then forwards the data to the central database securely over the internet through a 3G radio. The user, with minimal effort, can access the aggregated data and visualize the trends in real time on the BiB web portal. Paramount to the adoption and continued operation of an indoor sensing platform is battery lifetime. This design has achieved a multi-year lifespan by careful selection of components, an efficient binary communications protocol and data compression. Our BiB sensor is capable of collecting a rich set of environmental parameters, and is expandable to measure others, such as CO2. This paper describes the power characteristics of BiB sensors and their occupancy estimation and activity recognition functionality. Our vision is large-scale deployment of BiB in thousands of buildings, which would provide ample research opportunities and opportunities to identify ways to improve the building environment and energy efficiency.
Exercises for Children with Dyslalia-Software Infrastructure
Venue: arXiv cs.OH 2014
Year: 2014

In order to help children with dyslalia we created a set of software exercises. This set has a unitary software block (data base, programming language, programming philosophy). In this paper we present this software infrastructure with its advantage and disadvantage. The exercises are part of a software system named LOGOMON. Therefore, besides horizontal compatibilities (between exercises) vertical compatibilities are also presented (with LOGOMON system). Concerning database tables used for modulus of exercises, a part of them is "inherited" from LOGOMON application and another are specific for exercises application. We also need to specify that there were necessary minor changes of database tables used by LOGOMON. As programming language we used C#, implemented in Visual Studio 2005. We developed specific interfaces elements and classes. We also used multimedia resources that were necessary for exercises (images, correct pronouncing obtained from speech therapist recording, video clips). Another section of this application is related to loading of exercises on mobile devices (Pocket PC). A part of code has been imported directly, but there were a lot of files that need to be rewritten. Anyway, the multimedia resources were used without any processing.
An Experimental Study of Adaptive Control for Evolutionary Algorithms
Venue: arXiv cs.NE 2014
Year: 2014

The balance of exploration versus exploitation (EvE) is a key issue on evolutionary computation. In this paper we will investigate how an adaptive controller aimed to perform Operator Selection can be used to dynamically manage the EvE balance required by the search, showing that the search strategies determined by this control paradigm lead to an improvement of solution quality found by the evolutionary algorithm.
Network analysis of Zentralblatt MATH data
Venue: arXiv cs.SI 2014
Year: 2014

We analyze the data about works (papers, books) from the time period 1990-2010 that are collected in Zentralblatt MATH database. The data were converted into four 2-mode networks (works $\times$ authors, works $\times$ journals, works $\times$ keywords and works $\times$ MSCs) and into a partition of works by publication year. The networks were analyzed using Pajek -- a program for analysis and visualization of large networks. We explore the distributions of some properties of works and the collaborations among mathematicians. We also take a closer look at the characteristics of the field of graph theory as were realized with the publications.
Improving Efficiency and Scalability of Formula-based Debugging
Venue: arXiv cs.SE 2014
Year: 2014

Formula-based debugging techniques are becoming increasingly popular, as they provide a principled way to identify potentially faulty statements together with information that can help fix such statements. Although effective, these approaches are computationally expensive, which limits their practical applicability. Moreover, they tend to focus on failing test cases alone, thus ignoring the wealth of information provided by passing tests. To mitigate these issues, we propose two techniques: on-demand formula computation (OFC) and clause weighting (CW). OFC improves the overall efficiency of formula-based debugging by exploring all and only the parts of a program that are relevant to a failure. CW improves the accuracy of formula-based debugging by leveraging statistical fault-localization information that accounts for passing tests. Our empirical results show that both techniques are effective and can improve the state of the art in formula-based debugging.
Algorithms and Polynomiography for Solving Quaternion Quadratic Equations
Venue: arXiv cs.NA 2014
Year: 2014

Solving a quadratic equation $P(x)=ax^2+bx+c=0$ with real coefficients is known to middle school students. Solving the equation over the quaternions is not straightforward. Huang and So \cite{Huang} give a complete set of formulas, breaking it into several cases depending on the coefficients. From a result of the second author in \cite{kalQ}, zeros of $P(x)$ can be expressed in terms of the zeros of a real quartic equation. This drastically simplifies solving a quadratic equation. Here we also consider solving $P(x)=0$ iteratively via Newton and Halley methods developed in \cite{kalQ}. We prove a property of the Jacobian of Newton and Halley methods and describe several 2D polynomiography based on these methods. The images not only encode the outcome of the iterative process, but by measuring the time taken to render them we find the relative speed of convergence for the methods.
A One-Line Proof of the Fundamental Theorem of Algebra with Newton's Method as a Consequence
Venue: arXiv cs.NA 2014
Year: 2014

Many proofs of the fundamental theorem of algebra rely on the fact that the minimum of the modulus of a complex polynomial over the complex plane is attained at some complex number. The proof then follows by arguing the minimum value is zero. This can be done by proving that at any complex number that is not a zero of the polynomial we can exhibit a direction of descent for the modulus. In this note we present a very short and simple proof of the existence of such descent direction. In particular, our descent direction gives rise to Newton's method for solving a polynomial equation via modulus minimization and also makes the iterates definable at any critical point.
Rethinking the Contention Resolution Mechanism in WiMAX Networks using Lattice Correlators for Improved Smart Grid Communication Performance
Venue: arXiv cs.NI 2014
Year: 2014

By using experimental measurements of smart grid applications compliant with IEC 61850 in trace-driven WiMAX simulations, we show that the WiMAX MAC protocol efficiency decreases as a function of the number of stations. To avoid this shortcoming, we propose and analyze a novel WiMAX MAC protocol for smart grid applications, which uses lattice correlators to improve the throughput-delay performance significantly. For the considered configurations, the obtained maximum throughput of the proposed MAC protocol outperforms the current WiMAX MAC protocol by up to 41%.
History-free Collision Response for Deformable Surfaces
Venue: arXiv cs.GR 2014
Year: 2014

Continuous collision detection (CCD) and response methods are widely adopted in dynamics simulation of deformable models. They are history-based, as their success is strictly based on an assumption of a collision-free state at the start of each time interval. On the other hand, in many applications surfaces have normals defined to designate their orientation (i.e. front- and back-face), yet CCD methods are totally blind to such orientation identification (thus are orientation-free). We notice that if such information is utilized, many penetrations can be untangled. In this paper we present a history-free method for separation of two penetrating meshes, where at least one of them has clarified surface orientation. This method first computes all edge-face (E-F) intersections with discrete collision detection (DCD), and then builds a number of penetration stencils. On response, the stencil vertices are relocated into a penetration-free state, via a global displacement minimizer. Our method is very effective for handling penetration between two meshes, being it an initial configuration or in the middle of physics simulation. The major limitation is that it is not applicable to self-collision within one mesh at the time being.
Perfrewrite -- Program Complexity Analysis via Source Code Instrumentation
Venue: arXiv cs.PL 2014
Year: 2014

Most program profiling methods output the execution time of one specific program execution, but not its computational complexity class in terms of the big-O notation. Perfrewrite is a tool based on LLVM's Clang compiler to rewrite a program such that it tracks semantic information while the program executes and uses it to guess memory usage, communication and computational complexity. While source code instrumentation is a standard technique for profiling, using it for deriving formulas is an uncommon approach.