nils-herrmann/clean_scirepeval huggingface dataset:
Objective and subjective evaluation of light field image compression algorithms

This paper reports results of subjective and objective quality assessments of responses to a grand challenge on light field image compression. The goal of the challenge was to collect and evaluate new compression algorithms for light field images. In total seven proposals were received, out of which five were accepted for further evaluations. For objective evaluations, conventional metrics were used, whereas the double stimulus continuous quality scale method was selected to perform subjective assessments. Results show competitive performance among submitted proposals. However, in low bitrates, one proposal outperforms the others.
Error resilient macroblock rate control for H.264/AVC video coding

In this paper, an error resilient rate control scheme for the H.264/AVC standard is proposed. This scheme differs from traditional rate control schemes in that macroblock mode decisions are not made only to minimize their rate-distortion cost, but also take into account that the bitstream will have to be transmitted through an error-prone network. Since channel errors will probably occur, error propagation due to predictive coding should be mitigated by adequate Intra coding refreshes. The proposed scheme works by comparing the rate-distortion cost of coding a macroblock in Intra and Inter modes: if the cost of Intra coding is only slightly larger than the cost of Inter coding, the coding mode is changed to Intra, thus reducing error propagation. Additionally, cyclic Intra refresh is also applied to guarantee that all macroblocks are eventually refreshed. The proposed scheme outperforms the H.264/AVC reference software, for typical test sequences, for error-free transmission and several packet loss rates.
Spatial shape error concealment for object-based image and video coding

In this paper, an original spatial shape error-concealment technique, to be used in the context of object-based image and video coding schemes, is proposed. In this technique, it is assumed that the shape of the corrupted object at hand is in the form of a binary alpha plane, in which some of the shape data is missing due to channel errors. From this alpha plane, a contour corresponding to the border of the object can be extracted. However, due to errors, some parts of the contour will be missing and, therefore, the contour will be broken. The proposed technique relies on the interpolation of the missing contours with Be/spl acute/zier curves, which is done based on the available surrounding contours. After all the missing parts of the contour have been interpolated, the concealed alpha plane can be easily reconstructed from the fully recovered contour and used instead of the erroneous one improving the final subjective impact.
Performance Debugging of GPGPU Applications with the Divergence Map

The increasing programability and the high computational power of Graphical Processing Units (GPU) make them attractive to general purpose programming. However, taking full bene t of this execution environment is a challenging task. One of these challenges stem from divergences, a phenomenon that occurs when threads that execute in lock-step are forced to take di erent program paths due to branches in the code. In face of divergences, some threads will have to wait, idly, while their diverging siblings execute. Optimizing the code to avoid divergences is diffcult, because this task demands a deep understanding of programs that might be large and convoluted. In order to facilitate the detection of divergences, this paper introduces the divergence map, a data structure that indicates the location and the volume of divergences in a program. We build this map via dynamic profiling techniques, which we have implemented on top of an open source CUDA compiler. To illustrate the importance of the divergence map, we have used it to pin-point the core regions that must be optimized in well known public applications. By hand optimizing some applications, we have added 9-11% speedups onto kernels that have already gone through the sieve of many programmers.
A novel approach for the evaluation of electromagnetic fields using rigorous wire antenna models

Wire antenna models are a useful approach for studying small cylindrical elements using Integral Equation (IE) formulations [1, 2, 3]. For an accurate application of these models in the Method of Moments (MoM), some techniques must be derived in order to properly deal with the singularity of the kernel term, which is related to the behavior of the elliptic integral functions. In previous works exact expressions are obtained for the integration of the kernel along wire cells, but as a major drawback they are expressed in terms of infinite summations, which are slowly convergent near the singular condition of the observation point. In this work, an alternative technique is proposed, using a decomposition of the singular elliptic function in terms of a polynomial expansion . This method isolates the real singular term of the elliptic integral in a simple expression that can be performed analytically. The rest of the derived terms are regular, and numerical integration can be employed. Using this semianalytical approach, the different integrals involved in the evaluation of the electromagnetic fields can be evaluated with higher accuracy, as it will be shown in the communication.
Experimental Analysis of the Power Auto-Correlation-Based Chromatic Dispersion Estimation Method

We experimentally investigate the performance of the signal power autocorrelation-based method for chromatic dispersion (CD) estimation in a polarization-multiplexing quadrature phase-shift keying (PM-QPSK) 100G coherent optical system conveying optical channel transport unit level-4 (OTU4) frames. It is shown that the typical laboratory setup, where the signal components are generated from delayed versions of the same pseudorandom binary sequence (PRBS), is inadequate for experimental validation because of artifacts in the signal auto-correlation function. This problem is circumvented by the use of a commercial line card transporting independent data sequences. The algorithm is used to estimate accumulated CD values from 0 to 50 000 ps/nm under up to 80-ps differential group delay (DGD). We further evaluate its convergence properties in terms of the length of the sample vector required for correct CD estimation and address the hardware resource requirements. The CD-shifted version of the algorithm yielded a maximum estimation error of 186 ps/nm in all tested conditions.
Improving Turbo Codec Integration in Pixel-Domain Distributed Video Coding

The field of distributed video coding (DVC) theory has received a lot of attention in recent years and effective encoding techniques have been proposed. In the present work the framework of pixel domain Wyner-Ziv coding of video frames is considered, following the scheme proposed in A. Aaron et al. (2002). Some key frames are supposed to be available at the decoder while other frames are Wyner-Ziv encoded using turbo codes; at the decoder motion compensated interpolation between the key frames is performed in order to construct the side information for the Wyner-Ziv frame decoding. In this paper an improved model for the correlation noise between the side information frame and the original one is proposed. It is shown that modeling the nonstationary nature of the noise leads to substantial gain in the rate-distortion performance. Furthermore, by considering the memory of the noise, we show that some further gain can be obtained by placing an interleaver before the turbo codec so as to spread the correlation noise all over the frame
Robust control design for uninterruptible power systems

This paper presents a robust control strategy for uninterruptible power systems (UPS) based on the linear matrix inequality (LMI) framework. Taking into account the average model of the UPS, a state feedback controller is proposed that assures the local stability of the closed-loop system for all admissible load variation while minimizing an upper-bound on the 2-norm of the input-to-output operator. A real-life example is used to demonstrate the approach.
Extending input-output place-transition Petri nets for distributed controller systems development

Petri nets have been widely used in the design of embedded controllers, namely in electronic hardware and computing platforms design, as well as within automation application areas. This paper presents updated characteristics of one class of Petri nets, named Input-Output Place-Transition Petri nets (IOPT nets), extended to support networked embedded controllers design and globally-asynchronous locally-synchronous (GALS) systems modeling, together with its associated metamodel and execution semantics. The proposed meta-model is compliant with the Petri Net Markup Language (PNML) metamodel, augmented with the descriptions for inputs and outputs, as well as for time domains and communication channels. The meta-model is described using UML class diagrams and has an equivalent Ecore meta-model that positioning IOPT nets within the Eclipse Modeling Framework (EMF).
Monitoring an ocean outfall using an AUV

The wastewater plumes are shown to be very difficult to observe in detail. Several studies already conducted exhibit very complex and patchy structures both in vertical and horizontal sections. It is not clear if this plume patchiness is due to physical processes or measurement limitations. Rapid tow-yo sampling is expected to reduce the time variability during and between transects. The AUVs may be a useful instrument to map and detect wastewater plumes. This paper presents several prediction studies using time series files of actual in-situ measurements integrated in a near field model. The model predictions of the plume characteristics at the end of near field support the definition of the best sampling strategy for an AUV monitoring mission in a Portuguese west coast outfall.
Refreshment need metrics for improved shape and texture object-based resilient video coding

Video encoders may use several techniques to improve error resilience. In particular, for video encoders that rely on predictive (inter) coding to remove temporal redundancy, intra coding refreshment is especially useful to stop error propagation when errors occur in the transmission or storage of the coded streams, which can cause the decoded quality to decay very rapidly. In the context of object-based video coding, the video encoder can apply intra coding refreshment to both the shape and the texture data. In this paper, shape refreshment need and texture refreshment need metrics are proposed which can be used by object-based video encoders, notably MPEG-4 video encoders, to determine when the shape and the texture of the various video objects in the scene should be refreshed in order to improve the decoded video quality, e.g., for a given bitrate.
Reachable set approximation for measure driven dynamic control systems

In the article a conceptual approach towards the computation of polyhedral approximations of the reachable set of an impulsive dynamic control system is presented. This method consists in computing a sufficiently large number of points close to the boundary of the reachable set by regarding each one as the value at the final time of the optimal state trajectory for an optimal impulsive control problem with a certain linear cost functional. The iterative algorithm used to solve the optimal impulsive control problem involves its implicit transformation into a conventional one by the so called reduction transformation method. The auxiliary reduced problem is solved by an improvement algorithm based on local approximations to the reachable set.
Repetitive controller design for uninterruptible power supplies: An LMI approach

This paper proposes a semidefinite programming approach for designing repetitive controllers applied to uninterruptible power supplies. Considering a state space realization of a standard repetitive controller, Lyapunov-Krasovskii stabilization design conditions are cast in terms of linear matrix inequalities which are numerically solved by standard software packages. These conditions ensure the closed-loop stability for a set of admissible loads which is supposed known a priori. Experimental results are presented to demonstrate the effectiveness of the proposed design conditions.
Ultrasound characterization of coronary artery wall in vitro using temperature-dependent wave speed

Temperature dependence of the speed of sound, /spl part/c//spl part/T, is examined as a parameter to characterize tissue-equivalent phantoms and coronary artery tissue in vitro. The experimental system comprises an ultrasound biomicroscope, operating at center frequency of 50 MHz, and a temperature controlled micropositioning sample cell. Radio frequency (RF) backscattered signals were recorded, with a digital oscilloscope, from 64 independent positions and at 5 temperatures starting at 31/spl deg/C (phantom) and 36/spl deg/C (tissue) in steps of one degree. Time shift per degree Celsius (/spl part/t//spl part/T) was obtained with a correlation technique applied between gated sections of two RF-signals collected with one degree temperature difference from the same location in the sample. The average , calculated for every position of the gated sections along the propagation axis of the ultrasound beam, has the slope proportional to the difference between the linear coefficient of thermal expansion and the thermal sensitivity of the speed of sound. Calibration measurements of /spl part/c//spl part/T, made with single- and three-layer tissue equivalent phantoms, correlated well (r/spl ges/0.91) with those measured by the time-of-flight substitution method. The /spl part/c//spl part/T was estimated for the three layers on the wall of eight samples of human coronary arteries, obtained at autopsy from four individuals. The /spl part/c//spl part/T for the intima layers decreases as the disease progresses from mild intimal thickening to a more advanced atherosclerosis.
Airgap induction of five-phase induction machines operating with one opened phase

The distribution of the induction in the airgap of five-phase induction machines operating with an open phase is investigated. Analytical expressions are given in terms of steady-state symmetrical components which are related directly to the airgap induction. It is shown that under fault, third harmonic induction components arise which can potentially produce extra magnetic losses in the stator and rotor. Three operation modes are assessed: uncontrolled, current control with joule losses minimization, and current control with equal stator currents. The results for a prototype machine are discussed considering winding losses, torque pulsations, and the distortion of the airgap induction compared with the normal operation.
Coalition formation with communication ranges and moving targets

A team of unmanned aerial vehicles (UAVs) with limited communication ranges and limited resources are deployed in a region to search and destroy stationary and moving targets. When a UAV detects a target, depending on the target resource requirement, it is tasked to form a coalition over the dynamic network formed by the UAVs. In this paper, we develop a mechanism to find potential coalition members over the network using principles from internet protocol and introduce an algorithm using Particle Swarm Optimization to generate a coalition that destroys the target is minimum time. Monte-Carlo simulations are carried out to study how coalition are formed and the effects of coalition process delays.
A novel technique for the analysis of complex antennas with rotational symmetry using a simple thick wire model

A simple technique based on the analysis of thick wire elements is applied to the characterization of complex antennas exhibiting rotational symmetry. Results show that the technique allows the accurate analysis of complex antennas, of thick radius above 0.1/spl lambda/, composed of cylindrical and conical elements. The value of the derived approach is that it can replace otherwise time consuming numerical techniques based on surface discretization, while achieving a similar degree of accuracy.
Cooperative Autonomous Underwater Vehicle localization

Due to some communication constraints of the underwater environment, cooperative localization for AUVs is a hard task. In this paper, we present the state of the art in this area, analyse the existing solutions to related problems and propose 2 algorithms, based on the EKF, to solve the localization problem with a group of Autonomous Underwater Vehicles equipped with low cost navigation systems in an unknown environment. Without the aid of a global positioning system, the navigation error will grow unbounded. However, navigation performance can be greatly improved with our cooperative navigation scheme, as shown in simulations. We also show that the methods give better results when compared to an existing solution and perform a nonlinear observability analysis of the system to show the boundedness of the error with the aid of a global positioning system.
Evaluating location fingerprinting methods for underground GSM networks deployed over Leaky Feeder

Accurate localization techniques have long been of major importance for safety systems and a lot of research has been conducted in the distributed computing field regarding its functionality and reliability. In the specific scenario of long yet narrow tunnels existing at CERN, localization methods will enable a number of applications and processes to substantially reduce human intervention. In this paper we evaluate the use of Fingerprinting techniques with GSM signal available throughout the LHC tunnel via a radiating cable and compare some methods to estimate the location. The existing GSM infrastructure and tunnel conditions seem to be favorable to the adoption of these Fingerprinting methods. Nevertheless significant variations in the signal have been observed which might be traced back to different operational states of accelerator equipment. These effects and their sources will be analyzed in more detail in order to improve the applied techniques and their accuracy under such challenging conditions.
From IOPT Petri nets to C: An automatic code generator tool

This paper presents a tool for automatic generation of ANSI C code from models expressed in IOPT (Input-Output Place-Transition) Petri Nets. The inputs of the tool are PNML (Petri Nets Mark-up Language) files containing the IOPT Petri net models. The tool has two different interfaces: one relying on a simple graphical interface (amenable to be used by humans), and a second one with a command line interface (amenable to be used by humans as well as by other computational systems supporting tools interaction). The tool also allows the user to tune some parts of the automatically generated code considering some characteristics of the implementation platform improving the performance of the generated code. Generated code can be directly deployed into specific controllers; PIC low-cost microcontrollers as well as general purpose PCs have been used for validation.
Low-Frequency Model for Rectangular Semi-Anechoic Chambers

An efficient and accurate method to compute the electromagnetic field inside a rectangular semi-anechoic chamber from 30 to 100 MHz is provided. A modal analysis method is used to develop the homogeneous and inhomogeneous solution. They are then combined with a generalized circuital analysis to take into account the effect of the several layers of ferrite and dielectrics on the walls. Several numerical results of the normalized site attenuation (NSA) of a semi-anechoic chamber are provided and compared with measurements, showing a very good agreement
Quadratic modeling rate control in the emerging HEVC standard

The High Efficiency Video Coding (HEVC) standardization project mainly aims at improving the compression efficiency beyond the state-of-the-art H.264/AVC standard for high and ultra high definition video contents. The HEVC codec reference software, still under development, encodes video content using a fixed quantization step, thus leading to a variable bitrate stream which may not be suitable for the many multimedia applications where a constant bandwidth is required. Therefore, a rate control algorithm must be integrated in the HEVC codec taking into account that the novel coding tools further reduce the bitrate associated to texture data while increase the bitrate associated to the auxiliary information, e.g. motion vectors and coding modes. In this context, this paper studies the integration of a quadratic modeling rate control algorithm in the HEVC codec. Experimental results reveal that the rate control enabled HEVC codec provides a lower rate-distortion performance regarding a fixed quantization step HEVC codec, notably spending up to 20.12% more bitrate for the same objective quality. However, the integrated rate control algorithm offers lower bitrate fluctuations along the video contents than the HEVC codec with fixed quantization step.
A neural network strategy applied in autonomous mobile localization

In this article, a new approach to the problem of indoor navigation based on ultrasonic sensors is presented, where artificial neural networks (ANN) are used to estimate the position and orientation of a mobile robot. This approach proposes the use of three Radial Basis Function (RBF) Networks, where environment maps from an ultrasonic sensor and maps synthetically generated are used to estimate the robot localization. The mobile robot is mainly characterized by its real time operation based on the Matlab/Simulink environment, where the whole necessary tasks for an autonomous navigation are done in a hierarchical and easy reprogramming way. Finally, practical results of real time navigation related to robot localization in a known indoor environment are shown.
Model of a five-phase induction machine allowing for harmonics in the air-gap field part II : transformation of co-ordinates and d-q models

The first part of the paper presented and discussed the calculation of the main parameters of a five-phase induction machine. In this second part, co-ordinate transformations are introduced and applied to the general equations, resulting in a simpler set which has proved more appropriate for machine simulation and control. The transformations contain complex values and the new set of equations is described in terms of generalized symmetrical components. It is shown that each symmetrical component relates to a set of air-gap field harmonics and produces a corresponding torque. Mathematical expressions relating the harmonic order and the symmetrical components are derived and discussed. It is also shown that for each harmonic wave considered in the model, there exists one independent equivalent circuit and one set of independent voltage equations. From the d-q model obtained, it is possible to evaluate the influence of each space harmonic on the machine behavior and establish the base for the vector control of high-phase machines. Finally, the transformed equations allow the introduction of an independent d-q reference system for each harmonic considered.
Simultaneous Control, Navigation and Target Tracking for Robotic Formations

This paper describes a preliminary and innovative approach to integrated cooperative control and navigation of multi robots dynamic formations that encompasses the simultaneous tracking of opponent team players in robotic football games. Unlike traditional approaches that use self-localization to distribute object position estimates, a coordinated approach to cooperative formation navigation is proposed. The control architecture is based in a hierarchic hybrid systems approach, where distributed maneuvers allow simultaneous navigation and coordination. Our main contributions reside in an integrated control and navigation design framework yielding cooperative localization maneuvers and also some specific maneuver results on both formation estimation and global localization of two robots and two landmarks with bearing only measurements