Video quality protection for real time video streams over wireless networks

Received video quality is dependent on the available link rate and the packet loss ratio, which are correlated in a busy network link. Even low packet loss ratios (PLRs) can significantly reduce the video quality. In this paper, a packet level parity Forward Error Correction (FEC) is applied to the video stream in order to reduce the video PLR. A constant gross data rate is assumed, such that adding a FEC leads to a decrease in effective video data rate. The FEC block is truncated at the end of each video VOP, such that there are no inter-VOP dependencies for FEC correction. An algorithm is proposed to optimize the FEC length, based on the Quality of Experience as modelled by the ITU-T R G.1070 standard. It is shown that the optimization algorithm can significantly increase the video quality, without increasing the gross data rate. The algorithm has been evaluated both analytically and through simulations, which confirm the very significant increases in subjective video quality.     

Gate sizing using geometric programming

A two-step transistor sizing optimization method based on geometric programming for delay/area minimization is presented. In the first step, Elmore delay is minimized using only minimum and maximum transistor size constraints. In the second step, the minimized delay found in the previous step is used as a constraint for area minimization. In this way, our method can target simultaneously both delay and area reduction. Moreover, by relaxing the minimized delay, one may further reduce area with small delay penalty. Gate sizing may be accomplished through transistor sizing tying each transistor inside a cell to a same scale factor. This reduces the solution space, but also improves runtime as less variables are necessary. To analyze this tradeoff between execution time and solution quality a comparison between gate sizing and transistor sizing is presented. In order to qualify our approach, the ISCAS??85 benchmark circuits are mapped to a 45?nm technology using a typical standard cell library. Gate sizing and transistor sizing are performed considering delay minimization. Gate sizing is able to reduce delay in 21?%, on average, for the same area and power values of the sizing provided by standard-cells library. Then, the transistor sizing is executed and delay can be reduced in 40.4?% and power consumption in 2.9?%, on average, compared to gate sizing. However, the transistor sizing takes about 23 times longer to be computed, on average, using a number of variables twice higher than gate sizing. Gate sizing optimizing area is executed considering a delay constraint. Three delay constraints are considered, the minimum delay given by delay optimization and delay 1 and 5?% higher than minimum delay. An energy/delay gain (EDG) metric is used to quantify the most efficient tradeoff. Considering the minimum delay, area (power) is reduced in 28.2?%, on average. Relaxing delay by just 1?%, area (power) is reduced in 41.7?% and the EDG metric is 41.7. Area can be reduced in 51?%, on average, relaxing delay by 5?% and EDG metric is 10.2.     

Teamwork assessment in the educational web of data: A learning analytics approach towards ISO 10018

The Web of Data is an emerging research field that contributes to make better decisions because it gathers, combines and analyses different data sources available worldwide. Educational data is an interesting domain because it deals with the quality of the education itself and educational institutions which are common goals for every country. This paper is devoted to present how this idea has been used to improve a learning analytics tool. By means of this tool, teachers can perform teamwork competence assessment of a group of students taking into account how the individuals acquire the essential components of such competence. In this sense, authors use the Comprehensive Training Model of the Teamwork Competence in Engineering Domain (CTMTC) method to gather competence evidences and improve the system with a learning analytics tool to support the process. This tool is able to transform competence evidences and stores them in a competence ontology built upon ISO 10018 concepts. The final result is the production of educational results for the web of data.     

Maximum Likelihood-Based Direction-of-Arrival Estimator for Discrete Sources

This paper addresses the problem of direction-of-arrival (DOA) parameter estimation in array processing when the signals are inherently discrete, which is the case mainly in the digital communication context. Based on the particular structure of the signal space in the data model, a maximum likelihood-based approach is introduced. The strategy consists in transforming the parameter estimation problem into a decision task. It is shown through numerical simulations that the proposed solution closely follows the performance limit given by the Cramér–Rao bound. Some important features of the technique are as follows: (i) it is capable of handling any number of sources, provided that the number of sensors is greater than or equal to two and the number of snapshots is sufficiently greater than the cardinality of the signal space; (ii) the estimation quality is not affected by the angle and phase separation; and (iii) it offers the possibility to deal with uncalibrated arrays.     

Recyclable,Flexible, Low‐Power Oxide Electronics

The ability to process and dimensionally scale field‐effect transistors with and on paper and to integrate them as a core component for low‐power‐consumption analog and digital circuits is demonstrated. Low‐temperature‐processed p‐ and n‐channel integrated oxide thin‐film transistors in the complementary metal oxide semiconductor (CMOS) inverter architecture are seamlessly layered on mechanically flexible, low‐cost, recyclable paper substrates. The possibility of building these circuits using low‐temperature processes opens the door to new applications ranging from smart labels and sensors on clothing and packaging to electronic displays printed on paper pages for use in newspapers, magazines, books, signs, and advertising billboards. Because the CMOS circuits reported constitute fundamental building blocks for analog and digital electronics, this development creates the potential to have flexible form factor computers seamlessly layered onto paper. The holistic approach of merging low‐power circuitry with a recyclable substrate is an important step towards greener electronics.     

Autonomous and teleoperation control of a mobile robot

The present work proposes an autonomous tracking control system and a control structure to combine autonomous and teleoperation commands in a bicycle-type mobile robot. This compounded operation renders great flexibility to the control system of the mobile robot. For autonomous operation, a simple tracking controller that includes compensation of the robot dynamics is developed. This tracking control system is proved to be stable in the sense that it asymptotically reaches the tracking objective. Teleoperation with visual access to the robot’s workspace is integrated via a joystick with the autonomous operation of the robot. Simulations and experimental results on a prototype robot show the feasibility and performance of the proposed control system.     

Photonic Hydrogels from Chiral Nematic Mesoporous Chitosan Nanofibril Assemblies

Iridescence in animals and plants often arises from structural coloration, which involves hierarchical organization of minerals and biopolymers over length scales of the visible spectrum, leading to diffraction of light. In this work, discarded crustacean shells that are not known for their structural colors are used to produce photonic nanostructures of large, freestanding chiral nematic mesoporous chitosan membranes with tunable iridescent color. Bioinspired by colorful nanostructures in nature, photonic hydrogels with Bouligand‐type organization are fabricated from the twisted mesoporous membranes, where the chitosan nanofibrils are a novel precursor for surface acetylation and are also a biotemplate for polymerizing methyl methacrylate. The colors of the hydrogels can be tailored by swelling as they show large volume changes in response to changes in solvent environment.     

Availability modeling of energy management systems

Energy management system (EMS) computer architectures have changed significantly over the recent past increasing the difficulty and the need for a priori assessment of system performance and dependability. The old practice based on measurements is no longer acceptable because of the flexibility accrued with the deployment of the new distributed computer-based systems. The number of “what if” questions increased since EMS systems are now implemented using multiple workstations that can be interconnected in various different ways.In this paper we show how alternative configurations can be modeled and analyzed, before proposing and purchasing any equipment, with the assistance of Markov reward models. We review the concept of Markov reward models and show how they can be applied in the availability analysis of SCADA/EMS computer systems. The paper also presents a software tool that facilitates automatic generation and solution of large Markov reward models. The input language of this modeling tool uses a variation of stochastic Petri nets called stochastic reward nets, which are also reviewed. We believe this is the first time a detailed quantitative model of a SCADA/EMS computer system is proposed and solved in the general literature.     

A lesson from Argentina: Setting transmission tolls in a competitive auction is much better than regulating them

There are at least two procedures for setting the tolls paid by power line users. One consists of regulating them in a standard process. The other, which is used in Argentina, involves auctioning the lines to the lowest toll. In this paper we show that an auction yields higher expected social welfare if n ≥ 2 bid. Expected social welfare is even higher if, as in Argentina, those who benefit from the line can also bid and build. Moreover, when the social welfare is utilitarian, an auction beats regulation even when the regulator can perfectly audit costs ex post.We describe and examine the auction of the fourth Comahue transmission line in Argentina. Assuming that the regulator's information about costs is similar to the information held by the industry, the model suggests that had tolls been regulated, they would have been at least 61% higher.     

Analysis of EMG and acceleration signals for quantifying the effects of deep brain stimulation in Parkinson's disease

Deep brain stimulation (DBS) is effective in reducing motor symptoms in Parkinson's disease (PD). However, objective methods for quantifying its efficacy are lacking. We present a principal component (PC)-based tracking method for quantifying the effects of DBS in PD by using electromyography (EMG) and acceleration measurements. Ten parameters capturing PD characteristic signal features were initially extracted from isometric EMG and acceleration recordings. Using a PC approach, the original parameters were transformed into a smaller number of PCs. Finally, the effects of DBS were quantified by examining the PCs in a low-dimensional feature space. The EMG and acceleration data from 13 PD patients with DBS ON and OFF, and 13 healthy age-matched controls were used for analysis. Clinical evaluation of patients showed that their motor symptoms were effectively reduced with DBS. The analysis results showed that the signal characteristics of 12 patients were more similar to those of the healthy controls with DBS ON than with DBS OFF. These observations indicate that the PC-based tracking method can be used to objectively quantify the effects of DBS on the neuromuscular function of PD patients. Further studies are suggested to estimate the clinical sensitivity of the method to different types of PD.