OpenRaiser/Intern-Atlas huggingface dataset:
Analyzing Conflict Freedom For Multi-threaded Programs With Time Annotations
Venue: arXiv cs.PL 2014
Year: 2014

Avoiding access conflicts is a major challenge in the design of multi-threaded programs. In the context of real-time systems, the absence of conflicts can be guaranteed by ensuring that no two potentially conflicting accesses are ever scheduled concurrently.In this paper, we analyze programs that carry time annotations specifying the time for executing each statement. We propose a technique for verifying that a multi-threaded program with time annotations is free of access conflicts. In particular, we generate constraints that reflect the possible schedules for executing the program and the required properties. We then invoke an SMT solver in order to verify that no execution gives rise to concurrent conflicting accesses. Otherwise, we obtain a trace that exhibits the access conflict.
Queries on LZ-Bounded Encodings
Venue: arXiv cs.DS 2014
Year: 2014

We describe a data structure that stores a string $S$ in space similar to that of its Lempel-Ziv encoding and efficiently supports access, rank and select queries. These queries are fundamental for implementing succinct and compressed data structures, such as compressed trees and graphs. We show that our data structure can be built in a scalable manner and is both small and fast in practice compared to other data structures supporting such queries.
Complexity in the Context of Systems Approach to Project Management
Venue: arXiv cs.SE 2014
Year: 2014

Complexity is an inherent attribute of any project. The purpose of defining and documenting complexity is to have an early warning tool allowing a project team to focus on certain areas and aspects of the project in order to prevent and alleviate future risks and issues caused by this complexity. The main contribution of this paper is to present a systematic view of complexity in project management by identifying its key attributes and classifying complexity by these attributes. A "complexity taxonomy", based on a survey of the existing complexity literature, is developed and discussed including the product, project, and external environment dimensions. We show how complexity types are described through simple real life examples and business cases. Then we develop a framework (tool) for applying the notion of complexity as an early warning tool for a project manager in order to timely foresee future risks and problems. The paper is intended for researchers in complexity, project management, information systems, technology solutions and business management, and also for information specialists, project managers, program managers, financial staff and technology directors.
It's Not Easy Being Three: The Approximability of Three-Dimensional Stable Matching Problems
Venue: arXiv cs.CC 2014
Year: 2014

In 1976, Knuth asked if the stable marriage problem (SMP) can be generalized to marriages consisting of 3 genders. In 1988, Alkan showed that the natural generalization of SMP to 3 genders ($3$GSM) need not admit a stable marriage. Three years later, Ng and Hirschberg proved that it is NP-complete to determine if given preferences admit a stable marriage. They further prove an analogous result for the $3$ person stable assignment ($3$PSA) problem. In light of Ng and Hirschberg's NP-hardness result for $3$GSM and $3$PSA, we initiate the study of approximate versions of these problems. In particular, we describe two optimization variants of $3$GSM and $3$PSA: maximally stable marriage/matching (MSM) and maximum stable submarriage/submatching (MSS). We show that both variants are NP-hard to approximate within some fixed constant factor. Conversely, we describe a simple polynomial time algorithm which computes constant factor approximations for the maximally stable marriage and matching problems. Thus both variants of MSM are APX-complete.
Optimizing a Personalized Multigram Cellphone Keypad
Venue: arXiv cs.HC 2014
Year: 2014

Current layouts for alphabetic input on mobile phone keypads are very inefficient. We propose a genetic algorithm (GA) to find a suitable keypad layout for each user, based on their personal text history. It incorporates codes for frequent multigrams, which may be directly input. This greatly reduces the average number of strokes required for typing. We optimize for two-handed use, the left thumb covering the leftmost rows and vice versa. The GA mini- mizes the number of strokes, consecutive use of the same key, and consecutive use of the same hand. Using these criteria, the algorithm re-arranges the 26 alphabetic characters, plus 14 additional multigrams, on the 10-key pad. We demonstrate that this arrangement can generate a more effective layout, especially for SMS-style messages. Substantial savings are verified by both computational analysis and human evaluation.
Sequential Operations in LogicWeb
Venue: arXiv cs.PL 2014
Year: 2014

Sequential tasks cannot be effectively handled in logic programming based on classical logic or linear logic. This limitation can be addressed by using a fragment of Japaridze'sSequential tasks cannot be effectively handled in logic programming based on classical logic or linear logic. This limitation can be addressed by using a fragment of Japaridze's computability logic. We propose \seqweb, an extension to LogicWeb with sequential goal formulas. SeqWeb extends the LogicWeb by allowing goals of the form $G\seqand G$ and $G\seqor G$ where $G$ is a goal. These goals allow us to specify both sequential-conjunctive and sequential-disjunctive tasks. computability logic. We propose \seqweb, an extension to LogicWeb with sequential goal formulas. SeqWeb extends the LogicWeb by allowing goals of the form $G\seqand G$ and $G\seqor G$ where $G$ is a goal. These goals allow us to specify both sequential-conjunctive and sequential-disjunctive tasks.
Analysis and Design Specifications for Full-Duplex Radio Transceivers under RF Oscillator Phase-Noise with Arbitrary Spectral Shape
Venue: arXiv cs.IT 2014
Year: 2014

In this paper, the effects of oscillator phase-noise with arbitrary spectral characteristics on self-interference cancellation capability of a full-duplex radio transceiver are addressed, and design considerations are given for oscillator designers for optimized PLL design for full-duplex radio application. The paper first gives a full-duplex transceiver model that inherently mitigates most of the phase-noise effect from the self-interference signal. The remaining effect of the phase noise is then analysed. Closed-form solutions for the self-interference power are then derived. In the simulations part, a practical phase-locked loop type oscillator is used, which is based on the arbitrary mask phase-noise model. Analytical derivations are verified with the simulations, and the self-interference cancellation performance is thoroughly studied with various parameters. Design considerations are finally given for oscillator design for full-duplex radio transceivers, with the help of tangible parameters of the phase-locked loop type oscillators.
CLAZY: Lazy Calling for Common Lisp
Venue: arXiv cs.PL 2014
Year: 2014

This document contains a description of a Common Lisp extension that allows a programmer to write functional programs that use "normal order" evaluation, as in "non-strict" languages like Haskell. The extension is relatively straightforward, and it appears to be the first one such that is integrated in the overall Common Lisp framework.
Throat Finding Algorithms based on Throat Types
Venue: arXiv cs.CG 2014
Year: 2014

The three-dimensional geometry and connectivity of pore space determines the flow of single-phase incompressible flow. Herein I report on new throat finding algorithms that contribute to finding the exact flow-relevant geometrical properties of the void space, including high porosity samples of X2B images, three-dimensional synchrotron X-ray computed microtomographic images, and amounting to over 20% porosity. These new algorithms use the modified medial axis that comes from the 3DMA-Rock software package. To find accurate throats, we classify three major throat types: mostly planar and simply connected type, non-planar and simply connected type, and non-planar and non-simply connected type. For each type, we make at least one algorithm to find the throats. Here I introduce an example that has a non-planar and simply connected throat, and my solution indicated by one of my algorithms. My five algorithms each calculate the throat for each path. It selects one of them, which has the smallest inner area. New algorithms find accurate throats at least 98% among 12 high porosity samples (over 20%). Also, I introduce a new length calculation in the digitized image. The new calculation uses three mathematical concepts: i) differentiability, ii) implicit function theorem, iii) line integral. The result can convert the discrete boundary of the XMCT image to the real boundary. When the real boundary has an arc shape, the new calculation has less than 1% relative error.
Textural Approach for Mass Abnormality Segmentation in Mammographic Images
Venue: arXiv cs.CV 2014
Year: 2014

Mass abnormality segmentation is a vital step for the medical diagnostic process and is attracting more and more the interest of many research groups. Currently, most of the works achieved in this area have used the Gray Level Co-occurrence Matrix (GLCM) as texture features with a region-based approach. These features come in previous phase for segmentation stage or are using as inputs to classification stage. The work discussed in this paper attempts to experiment the GLCM method under a contour-based approach. Besides, we experiment the proposed approach on various tissues densities to bring more significant results. At this end, we explored some challenging breast images from BIRADS medical Data Base. Our first experimentations showed promising results with regard to the edges mass segmentation methods. This paper discusses first the main works achieved in this area. Sections 2 and 3 present materials and our methodology. The main results are showed and evaluated before concluding our paper.
End-to-end Continuous Speech Recognition using Attention-based Recurrent NN: First Results
Venue: arXiv cs.NE 2014
Year: 2014

We replace the Hidden Markov Model (HMM) which is traditionally used in in continuous speech recognition with a bi-directional recurrent neural network encoder coupled to a recurrent neural network decoder that directly emits a stream of phonemes. The alignment between the input and output sequences is established using an attention mechanism: the decoder emits each symbol based on a context created with a subset of input symbols elected by the attention mechanism. We report initial results demonstrating that this new approach achieves phoneme error rates that are comparable to the state-of-the-art HMM-based decoders, on the TIMIT dataset.
Deep Learning for Answer Sentence Selection
Venue: arXiv cs.CL 2014
Year: 2014

Answer sentence selection is the task of identifying sentences that contain the answer to a given question. This is an important problem in its own right as well as in the larger context of open domain question answering. We propose a novel approach to solving this task via means of distributed representations, and learn to match questions with answers by considering their semantic encoding. This contrasts prior work on this task, which typically relies on classifiers with large numbers of hand-crafted syntactic and semantic features and various external resources. Our approach does not require any feature engineering nor does it involve specialist linguistic data, making this model easily applicable to a wide range of domains and languages. Experimental results on a standard benchmark dataset from TREC demonstrate that---despite its simplicity---our model matches state of the art performance on the answer sentence selection task.
Heart Rate Monitoring as an Easy Way to Increase Engagement in Human-Agent Interaction
Venue: arXiv cs.HC 2014
Year: 2014

Physiological sensors are gaining the attention of manufacturers and users. As denoted by devices such as smartwatches or the newly released Kinect 2 -- which can covertly measure heartbeats -- or by the popularity of smartphone apps that track heart rate during fitness activities. Soon, physiological monitoring could become widely accessible and transparent to users. We demonstrate how one could take advantage of this situation to increase users' engagement and enhance user experience in human-agent interaction. We created an experimental protocol involving embodied agents -- "virtual avatars". Those agents were displayed alongside a beating heart. We compared a condition in which this feedback was simply duplicating the heart rates of users to another condition in which it was set to an average heart rate. Results suggest a superior social presence of agents when they display feedback similar to users' internal state. This physiological "similarity-attraction" effect may lead, with little effort, to a better acceptance of agents and robots by the general public.
Primal-Dual Algorithms for Non-negative Matrix Factorization with the Kullback-Leibler Divergence
Venue: arXiv cs.LG 2014
Year: 2014

Non-negative matrix factorization (NMF) approximates a given matrix as a product of two non-negative matrices. Multiplicative algorithms deliver reliable results, but they show slow convergence for high-dimensional data and may be stuck away from local minima. Gradient descent methods have better behavior, but only apply to smooth losses such as the least-squares loss. In this article, we propose a first-order primal-dual algorithm for non-negative decomposition problems (where one factor is fixed) with the KL divergence, based on the Chambolle-Pock algorithm. All required computations may be obtained in closed form and we provide an efficient heuristic way to select step-sizes. By using alternating optimization, our algorithm readily extends to NMF and, on synthetic examples, face recognition or music source separation datasets, it is either faster than existing algorithms, or leads to improved local optima, or both.
Censorship Resistance: Let a Thousand Flowers Bloom?
Venue: arXiv cs.CR 2014
Year: 2014

This paper argues that one of the most important decisions in designing and deploying censorship resistance systems is whether one set of system options should be selected (the best), or whether there should be several sets of good ones. We model the problem of choosing these options as a cat-and-mouse game and show that the best strategy depends on the value the censor associates with total system censorship versus partial, and the tolerance of false positives. If the censor has a low tolerance to false positives then choosing one censorship resistance system is best. Otherwise choosing several systems is the better choice, but the way traffic should be distributed over the systems depends on the tolerance of the censor to false negatives. We demonstrate that establishing the censor's utility function is critical to discovering the best strategy for censorship resistance.
CoMIC: Good features for detection and matching at object boundaries
Venue: arXiv cs.CV 2014
Year: 2014

Feature or interest points typically use information aggregation in 2D patches which does not remain stable at object boundaries when there is object motion against a significantly varying background. Level or iso-intensity curves are much more stable under such conditions, especially the longer ones. In this paper, we identify stable portions on long iso-curves and detect corners on them. Further, the iso-curve associated with a corner is used to discard portions from the background and improve matching. Such CoMIC (Corners on Maximally-stable Iso-intensity Curves) points yield superior results at the object boundary regions compared to state-of-the-art detectors while performing comparably at the interior regions as well. This is illustrated in exhaustive matching experiments for both boundary and non-boundary regions in applications such as stereo and point tracking for structure from motion in video sequences.
SenseMyCity: Crowdsourcing an Urban Sensor
Venue: arXiv cs.CY 2014
Year: 2014

People treat smartphones as a second skin, having them around nearly 24/7 and constantly interacting with them. Although smartphones are used mainly for personal communication, social networking and web browsing, they have many connectivity capabilities, and are at the same time equipped with a wide range of embedded sensors. Additionally, bluetooth connectivity can be leveraged to collect data from external sensors, greatly extending the sensing capabilities. However, massive data-gathering using smartphones still poses many architectural challenges, such as limited battery and processing power, and possibly connectivity costs. This article describes SenseMyCity (SMC), an Internet of Things mobile urban sensor that is extensible and fully configurable. The platform consists of an app, a backoffice and a frontoffice. The SMC app can collect data from embedded sensors, like GPS, wifi, accelerometer, magnetometer, etc, as well as from external bluetooth sensors, ranging from On-Board Diagnostics gathering data from vehicles, to wearable cardiac sensors. Adding support for new internal or external sensors is straightforward due to the modular architecture. Data transmission to our servers can occur either on-demand or in real-time, while keeping costs down by only using the configured type of Internet connectivity. We discuss our experience implementing the platform and using it to make longitudinal studies with many users. Further, we present results on bandwidth utilization and energy consumption for different sensors and sampling rates. Finally, we show two use cases: mapping fuel consumption and user stress extracted from cardiac sensors.
A Two-layer Architecture of Mobile Sinks and Static Sensors
Venue: arXiv cs.NI 2014
Year: 2014

We propose a two-layer mobile sink and static sensor network (MSSSN) architecture for large scale wireless sensor networks. The top layer is a mobile ad hoc network of resource-rich sink nodes while the bottom layer is a network of static resource-constrained sensor nodes. The MSSSN architecture can be implemented at a lower cost with the currently available IEEE 802.11 devices that only use a single halfduplex transceiver. Each sink node is assigned a particular region to monitor and collect data. A sink node moves to the vicinity of the sensor nodes (within a few hops) to collect data. The collected data is exchanged with peer mobile sinks. Thus, the MSSSN architecture provides scalability, extends sensor lifetime by letting them operate with limited transmission range and provides connectivity between isolated regions of sensor nodes. In order to provide fault tolerance, more than one mobile sink could be collecting data from a given region or a mobile sink could collect data from more than one region. In the later half of the paper, we discuss several open research issues that need to be addressed while implementing the MSSSN architecture.
Multi-Branch Lattice-Reduction SIC for Multiuser MIMO Systems
Venue: arXiv cs.IT 2014
Year: 2014

In this paper, we propose a new detection technique for multiuser multiple-input multiple-output (MU-MIMO) systems. The proposed scheme combines a lattice reduction (LR) transformation, which makes the channel matrix nearly orthogonal, and then employs a multi-branch (MB) technique with successive interference cancellation (SIC). A single LR transformation is required for the receive filters of all branches in the scheme, which proposes a different ordering for each branch and generates a list of detection candidates. The best vector of estimated symbols is chosen according to the maximum likelihood (ML) selection criterion. Simulation results show that the proposed detection structure has a near-optimal performance while the computational complexity is much lower than that of the ML detector.
Interference Alignment Improves the Capacity of OFDM Systems
Venue: arXiv cs.IT 2014
Year: 2014

Multi-user Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Output Multiple Output (MIMO) have been widely adopted to enhance the system throughput and combat the detrimental effects of wireless channels. Recently, interference alignment was proposed to exploit interference to enable concurrent transmissions of multiple signals. In this paper, we investigate how to combine these techniques to further enhance the system throughput. We first reveal the unique characteristics and challenges brought about by using interference alignment in diagonal channels. We then derive a performance bound for the multi-user (MIMO) OFDM/interference alignment system under practical constraints, and show how to achieve this bound with a decomposition approach. The superior performance of the proposed scheme is validated with simulations.
Protection de la vie privée à base d'agents dans un système d'e-learning
Venue: arXiv cs.CR 2014
Year: 2014

The e-learning systems are designed to provide an easy and constant access to educational resources online. Indeed, E-learning systems have capacity to adapt content and learning process according to the learner profile. Adaptation techniques using advanced behavioral analysis mechanisms, called "Learner Modeling" or "Profiling". The latter require continuous tracking of the activities of the learner to identify gaps and strengths in order to tailor content to their specific needs or advise and accompany him during his apprenticeship. However, the disadvantage of these systems is that they cause learners' discouragement, for learners, alone with his screen loses its motivation to improve. Adding social extension to learning, to avoid isolation of learners and boost support and interaction between members of the learning community, was able to increase learner's motivation. However, the tools to facilitate social interactions integrated to E-learning platforms can be used for purposes other than learning. These needs, which can be educational, professional or personal, create a mixture of data from the private life and public life of learners. With the integration of these tools for e-learning systems and the growth of the amount of personal data stored in the databases of these latter, protecting the privacy of students becomes a major concern. Indeed, the exchange of profiles between e-learning systems is done without the permission of their owners. Furthermore, the profiling behavior analysis currently represents a very cost-effective way to generate profits by selling these profiles advertising companies. Today, the right to privacy is threatened from all sides. In addition to the threat from pirates, the source of the most dangerous threats is that from service providers online that users devote a blind trust. Control and centralized data storage and access privileges that have suppliers are responsible for the threat. Our work is limited to the protection of personal data in e-learning systems. We try to answer the question: How can we design a system that protects the privacy of users against threats from the provider while benefiting from all the services, including analysis of behavior? In the absence of solutions that take into account the protection and respect of privacy in e-learning systems that integrate social learning tools, we designed our own solution. Our "ApprAide" system uses a set of protocols based on security techniques to protect users' privacy. In addition, our system incorporates tools that promote social interactions as a social learning network, a chat tool and a virtual table. Our solution allows the use of adaptation techniques and profiling to assist learners. Keywords: Social learning, privacy, security, e-learning, agents