nils-herrmann/clean_scirepeval huggingface dataset:
Localisation system for an autonomous mobile platform

In this article, we present the design and development of a localisation system for a mobile autonomous platform. The purpose of this system is to endow this vehicle with the capability of maintaining a position estimate in real time without artificial aids in a structured environment. Each position estimate is generated from the previous one with information obtained from the on board sensors as well as from the world model. Process and observation models are built in such a way that take into account the physical restrictions of the vehicle and its ultra-sonic sonars. All the stages of the extended Kalman filtering (EKF) process applied to the vehicle of interest are described. To increase the performance of the sonar data real time acquisition, a method based on entropy choosing the sonar observation in order to minimise the uncertainty of the position estimate is used. An adaptive process of matching the sonar observation decreasing the possibility of loss of the vehicle is also chosen. Satisfactory results showing the good performance of this localisation system are presented.
4/spl times/2.5 Gb/s transmission over standard singlemode fiber with amplifier spacing of 160 km

A 4/spl times/2.5 Gb/s WDM transmission system was demonstrated over 740 km of standard singlemode fiber with amplifier spacing of 160 km. The four line amplifiers used have saturated output power of 12 dBm and non-equalized gain profile. To the authors' knowledge, this is the largest repeater spacing demonstrated for a WDM system without ASE filtering. Bit error rates as low as 10/sup -16/ were measured for received power ranging between -30 and -27 dBm, depending on the channel. The power penalties are below 2 dB for a bit error rate of 10/sup -9/. This penalty is mainly due to accumulated noise from the amplifiers.
Remote operation of embedded controllers designed using IOPT Petri-nets

This paper presents a new communication architecture to enable the remote control, monitoring and debug of embedded-system controllers designed using IOPT Petri nets. IOPT Petri nets and the related tools (http://gres.uninova.pt) have been used as a rapid prototyping and development framework, including model-checking, simulation and automatic code generation tools. The new architecture adds remote operation capabilities to the controllers produced by the automatic code generators, enabling quasi-real-time remote debugging and monitoring using the IOPT simulator tool. Furthermore, it enables the creation of graphical user interfaces for remote operation and the development of distributed systems where a Petri net model running on a central system supervises the actions of multiple remote subsystems.
Perceptual Visual Signal Compression and Transmission

One- and two-way communication with digital compressed visual signals is now an integral part of the daily life of millions. Such commonplace use has been realized by decades of advances in visual signal compression. The design of effective, efficient compression and transmission strategies for visual signals may benefit from proper incorporation of human visual system (HVS) characteristics. This paper overviews psychophysics and engineering associated with the communication of visual signals. It presents a short history of advances in perceptual visual signal compression, and describes perceptual models and how they are embedded into systems for compression and transmission, both with and without current compression standards.
Autonomous underwater vehicles for survey operations: theory and practice

This paper provides an overview of some of the missions and vehicle control functionality being considered for the rapidly developing technology of autonomous underwater vehicles. Spawned from the availability of small embedded processors and the increasing capabilities of underwater communications, these small untethered vehicles are expected to play a role as a force multiplier in expanding our ability to survey ocean areas. Missions expected to become viable in the near future include environmental monitoring, underwater inspection, geological survey as well as the current focus on military missions in mine countermeasures. This paper gives an outline of the functionality required of such vehicles and their relation to intelligent control technology, some implementation details, and the future needs for research that continue to drive our field toward a practical reality.
Strategy of localization using the neural network toolbox of the Matlab/Simulink applied to mobile robots

In this paper, it will be presented a strategy of localization of one mobile robot in a closed environment using the neural network toolbox of the Matlab/Simulink. The objective of the strategy is determine positions (x,y) in a closed environment, through of artificial neural networks (ANN). The paper describes the use of one of these tools, Matlab/Simulink, used in order to simulate and validate the results concerning the localization applied to a mobile robot.
Numerical Evaluation of the Green's functions for Arbitrarily Shaped Enclosures

In this paper, a new spatial method has been implemented for the efficient calculation of the mixed potential Green's functions associated to electrical sources, when they are placed inside arbitrarily-shaped cylindrical cavities. The technique consists of placing electric dipole images and charges outside the cavity, imposing, at discrete points of the metallic wall, the appropriate boundary conditions for the potentials. Results show that the numerical convergence is attained fast. The cut-off frequencies and potential patterns for a trapezium-shaped waveguide are compared to those obtained by a standard finite elements technique, showing excellent agreement. Furthermore, a printed planar filter shielded in a square cavity has been analyzed with the new Green's functions, showing the practical value of the new theory.
A Novel Low-Pass Filter Based on Rounded Posts Designed by an Alternative Full-Wave Analysis Technique

A new low-pass waveguide filter topology is proposed based on capacitive posts using rounded shapes. The new structure is designed using a technique that benefits from a full-wave integral equation simulation tool for arbitrarily shaped capacitive microwave circuits. This integral equation method enables one to apply an efficient filter design technique employing iris geometries other than rectangular discontinuities, such as the one based on rounded posts proposed in this work. A prototype using circular posts has been manufactured and measured obtaining excellent results as compared with predictions, thus demonstrating the practical feasibility of the new proposed filtering structure. A new filter using elliptic capacitive posts was compared in terms of multipactor risk against similar filters based on traditional rectangular windows and on rectangular posts. Simulation results indicate that the new proposed concept using rounded shapes leads to geometries that can double multipactor thresholds as compared with traditional filters.
Automatic generation of graphical user interfaces for VHDL based controllers

Recent trends in embedded systems can be categorized by high application sophistication, shorter product life cycles and low cost requirements. As system complexity increases, rapid application development platforms and user interface builders became an important factor to reduce design cost and time-to-market. The tools proposed in this paper enable the rapid development of applications and the respective user interfaces, with automatic VHDL code generation for FPGAs, without requiring the need to write a single line of code. With high processing power, capability to generate graphical images and interface with pointing devices, reconfigurable hardware platforms provide a very competitive solution for embedded systems.
A MATLAB/Simulink-based platform for real-time planning and execution of control techniques applied to mobile robots

Simulation tools now occupy a place of particular importance in many fields of engineering. Some of these tools have come to be regarded as standard and/or as a point of departure for the replication of results obtained in scientific papers. The present paper describes the use of one of these tools, Matlab/Simulink, used in order to simulate and validate in real time the results concerning the guidance, navigation and control techniques applied to a low cost mobile platform.
Characterization of dielectric materials with a modified DIRECT algorithm

An alternative technique is presented for the determination of the electrical properties of dielectric materials. Two dielectric elements are placed inside a rectangular waveguide and complex scattering parameters are used to extract their relative permittivity values. The technique is based on the modification of the DIRECT algorithm to cope with cost functions with large number of minima. To improve the reliability of the algorithm, a multimode analysis has also been introduced. Results demonstrate that considerable improvement in the prediction of the dielectric materials is obtained when the new algorithms are used.
A mobile audio-visual terminal for the DECT system

The recent explosion in the number of mobile terminals awoke the scientific community to the need of providing in a short time audio-visual services in mobile environments. Due to the low bandwidth available and the critical characteristics of mobile channels, audio and video source coding as well as channel coding became more complex and thus new solutions must be provided. This paper describes the technical solutions designed for the first prototype of an audio-visual mobile terminal with special emphasis in the video coding options.<<ETX>>
Practical Implementation of the Spatial Images Technique for the Analysis of Shielded Multilayered Printed Circuits

In this paper, a practical implementation of the spatial images technique for the analysis of shielded multilayered printed circuits inside convex cavities is proposed. A new method is introduced in order to automatically locate the images surrounding the structure in order to impose the appropriate boundary conditions for the potentials. The boundary conditions are imposed at discrete points along the cavity wall and, therefore, the technique proposed is an approximation to the exact cavity modeling. Furthermore, for the analysis of electrically long cavities, the use of several rings of images surrounding the entire cavity at different heights is employed. Using the special features of the formulation, a new method of moments implementation combined with the spatial images technique is proposed in order to efficiently analyze practical multilayered printed filters, considerably reducing the computational cost. Several examples with CPU time comparisons are provided, demonstrating the accuracy and efficiency of the new technique. A novel transversal filter in a trapezium-shaped cavity is designed, manufactured, and tested for the first time using the spatial images technique.
Quantitative and Qualitative Monitoring System for Switchgear With Full Electrical Isolation Using Fiber-Optic Technology

This paper presents the results of a quantitative and qualitative monitoring system for switchgear with full electrical isolation using fiber-optic technology that aims to help in the automation of substations. The remote sensors were installed near each phase of the switchgear and they are powered only by the optical power provided by one pair of optic fibers connected to a remote optical source. At the same time, part of the optical supply power is used to measure the contact quality by using the optical triangulation method. Two microcameras installed in each remote sensor allow for the observation of the switchgear contact and hinge. All data are transmitted by the optical fibers to a control unit installed in the substation room, and from that, the data are transmitted to the utilities' operating center using the utilities commercial telecom optical network. We describe the system design, laboratory tests, and the field trial conducted in a 138-kV distribution substation.
Protecting Programs Against Memory Violation In Hardware

The C and C++ programming languages do not prevent ouf-of-bounds memory access, consequently leaving room to attacks such as buffer overflow and buffer overread. There are several techniques to make C programs safe. However these methods are usually implemented via software and tend to cause performance degradation. Our work aims at a hardware solution which is able to check bounds efficiently, by providing novel instructions that are aware of a buffer's valid memory range. Whenever a violation is found the program will terminate, a typical hardware exception behavior.
Nondegenerate necessary conditions for optimal impulsive control problems with state constraints

A free time impulsive control problem with state constraints and equality and inequality constraints on the trajectory endpoints is considered in this article. After presenting an appropriate solution concept, necessary conditions of optimality in the form a Maximum Principle are stated. An essential feature of these conditions is that they do not degenerate, i.e., they remain informative even for abnormal control processes. These conditions are derived by using a penalty function method.
Estimation of parameters of induction machines from no-load starting without speed acquisition

The paper addresses the problem of practical estimation of the parameters of induction machines without speed measurement and using only no-load transient voltages and currents, acquired during a startup test performed at the final stage of the production line at the manufacturer site. The test aims to enable a first estimate of the machine parameters, from which standard performance requirements — such as starting torque, maximal torque, rated power factor and efficiency — can be checked using known models. A method is proposed to estimate the speed and electromagnetic torque alone from stator voltages and currents and also from measured stator resistance (Rs). Based on the estimated speed and torque, electrical and mechanical parameters are then estimated by the Classical Minimal Squares Method. To validate the method, simulation data are used, to which error to the stator resistance and noise to the currents and voltages are added. The results show that the proposed method is able to estimate the parameters with acceptable errors even with variations of ±20% in Rs and under different noise levels.
Evaluating MPEG-4 video decoding complexity for an alternative video complexity verifier model

MPEG-4 is the first object-based audiovisual coding standard. To control the minimum decoding complexity resources required at the decoder, the MPEG-4 Visual standard defines the so-called video buffering verifier mechanism, which includes three virtual buffer models, among them the video complexity verifier (VCV). This paper proposes an alternative VCV model, based on a set of macroblock (MB) relative decoding complexity weights assigned to the various MB coding types used in MPEG-4 video coding. The new VCV model allows a more efficient use of the available decoding resources by preventing the overevaluation of the decoding complexity of certain MB types and thus making it possible to encode scenes (for the same profile@level decoding resources) which otherwise would be considered too demanding.
Decoder side just noticeable distortion model estimation for efficient H.264/AVC based perceptual video coding

This paper proposes a decoder side estimation for a just noticeable distortion perceptual model integrated in the H.264/AVC codec to improve its RD performance. The proposed estimation avoids having to send the perceptual weights used during the quantization of each frequency coefficient. Experiments with high definition videos show that the novel perceptual video codec is able to reduce the bitrate up to about 34% at the cost of, at most, 1.2% objective multi scale structural similarity quality loss. Moreover, the RD performance with the estimation is comparable to the performance achieved if the original perceptual model is used at the decoder without considering the associated rate.
Reachability analysis of dynamic programming based controlled systems: An extended algorithm

This paper extends the algorithm proposed in . In , the numerical approximation of the solution of dynamic programming problems is used as a candidate Lyapunov function VL(x), in order to prove convergence of the closed loop system to a given target. That is done in the framework of sampled data systems. The described algorithm provides only a sufficient condition, which in many cases is not verified due to the deviations introduced by the approximations. In this paper, the previous algorithm is extended in order to compute the decrease in the candidate Lyapunov over multiple sampling periods, i.e., VL(x(k + n)) - VL(x(k)), with n ϵ N. Thus, it is expected that the verification procedure becomes more robust with respect to the deviations introduced by the numerical approximation of the control law and candidate Lyapunov function. The core of the algorithm is based on linear programming with polytopic convex constraints.
A reconfigurable mission control system for underwater vehicles

This paper describes the mission control software used in the LSTS/FEUP underwater vehicles. This software follows the guidelines of the generalized vehicle architecture, adapts the original idea to encompass the current application requirements and constitutes a first implementation. The work is focused on the design and implementation of an application that can be easily adapted to different vehicle configurations or even to different vehicles. One of the desired goals was to enhance software reusability and to establish a development environment that allows developers with a minimal knowledge of coding details to upgrade the application. To assist this purpose, a CASE tool, which provides modern software development techniques, was used. A simulation environment was also developed whose purpose is to test the applications and to detect possible malfunctions before they occur during mission execution.
FPGA based speed control of Brushless DC Motors using IOPT Petri Net models

This paper describes how to implement a functional Brushless DC Motor open-loop speed controller from simple IOPT Petri Net models, using the integrated development environment offered by IOPT-Tools, without the need to manually write software or hardware descriptions. IOPT nets are a Petri net class specifically designed to support the implementation of embedded system controllers. The IOPT-Tools Web service (http://gres.uninova.pt) includes an interactive graphical editor to design IOPT models, a model-checking framework consisting of a state-space generator and a query system, and automatic code generation tools to produce software (C) or hardware (VHDL) controller implementations. The Brushless DC Motor speed controller was decomposed into several subsystems, including a noise-filter, quadrature-decoder, PWM generator and an BLDC commutation-manager. These sub-systems were modeled using simple IOPT models, analyzed using the model-checking tools, resulting in the automatic creation of VHDL modules for each sub-system. To finish the entire project, a top VHDL module is used to instantiate copies of the automatically generated components and specify signals to connect the components to the external world. With the addition of an inverter board, a working prototype was implemented and successfully tested.
Mission Review and Analysis

This paper presents the mission review and analysis module of a C3I (command, control, communication and information) infrastructure-the Neptus framework. This is a mix-initiative environment that it's being developed in the Underwater Systems and Technology Laboratory (USTL/LSTS) with the goal to support the coordinated operation of heterogeneous teams of vehicles. This includes autonomous and remotely operated underwater, surface, land, and air vehicles and people. People perform a fundamental role, not only in the case of remotely operated vehicles, but also with autonomous vehicles where mix-initiative operation is a requirement. The Neptus is very modular and will be heavily based on services with a distributed architecture. This paper focus mainly on the mission review and analysis where the data collected in a mission is prepared for analysis
On properness of impulsive extension

This article investigates properness of an impulsive extension of the conventional optimal control problem. This includes both the correctness of the solution to impulsive control systems arising as result of an impulsive extension of ordinary differential systems, and existence theorems. Correctness in the classic Cauchy sense is proved. New approximation lemmas are introduced proved that guarantee the sensitivity to small perturbations in control variables. Filippov-type existence theorems are established.
Improved Feedback Compensation Mechanisms for Multiple Video Object Encoding Rate Control

This paper proposes new buffer and video object distortion feedback compensation mechanisms for efficiently dealing with deviations between the ideal and the actual behavior of video scene encoders when jointly encoding multiple arbitrarily shaped video objects in the context of compliant low-delay object-based MPEG-4 video coding. The proposed solution computes target buffer occupancies for each encoding time instant based on the amount and complexity of the video data to encode, and the bit allocation for each encoding time instant is feedback adjusted according to deviations relatively to this ideal behavior. Additionally, each video object bit allocation is also feedback adjusted based on the relative distortion of the various video objects in the scene. The proposed solution outperforms the non-normative MPEG-4 reference rate control algorithm for a wide range of bit rates and spatio-temporal resolutions, for typical test sequences.
Real-time hybrid control of multiple autonomous underwater vehicles

In this paper we discuss a hybrid systems framework for the real-time multi-agent coordination and control of multiple vehicles in the context of the Multiple Autonomous Underwater Vehicles for Coastal Oceanography project from Porto University. We address the use of hybrid systems techniques for analyzing and synthesizing the control architecture and describe how it can be implemented using the DIADEM system. DIADEM is an object-oriented framework for implementing real-time, event-driven, distributed multi-agent control systems.
A new fast motion estimation and mode decision algorithm for H.264 depth maps encoding in free viewpoint TV

In this paper, we consider a scenario where 3D scenes are modeled through a View+Depth representation. This representation is to be used at the rendering side to generate synthetic views for free viewpoint video. The encoding of both type of data (view and depth) is carried out using two H.264/AVC encoders. In this scenario we address the reduction of the encoding complexity of depth data. Firstly, an analysis of the Mode Decision and Motion Estimation processes has been conducted for both view and depth sequences, in order to capture the correlation between them. Taking advantage of this correlation, we propose a fast mode decision and motion estimation algorithm for the depth encoding. Results show that the proposed algorithm reduces the computational burden with a negligible loss in terms of quality of the rendered synthetic views. Quality measurements have been conducted using the Video Quality Metric.