Classical and modern methods for time-constrained energy optimal motion – Application to a badminton robot

Two control approaches are presented to improve the energy efficiency of a robot which has to perform point-to-point motions during a fixed time interval. One is called Proximate Energy Optimal Servo (PEOS) and the other is called Energy-Optimal Model Predictive Control (EOMPC). The PEOS approach is based on the Proximate Time Optimal Servo (PTOS) control algorithm whose parameters are optimized in order to achieve energy efficient behavior. The EOMPC approach developed based on the Time-Optimal Model Predictive Control (TOMPC) approach achieves energy optimal performance by minimizing the energy losses in the object function. The two developed approaches are applied to a robot playing badminton and compared to two existing control approaches: the Proximate Time Optimal Servo (PTOS) and the Time-Optimal Model Predictive Control (TOMPC). The robot is still able to intercept most of the opponent shuttles on time, while a significant reduction of the energy consumption is demonstrated in both cases.     

Feasibility and modelling for convergence of optical-wireless network – A review

Now a days, the convergence of wireless and optical network gaining popularity to enhance the data carrying capacity, QoS and to support future multimedia applications. The queue theory plays an important role for analytically evaluating such converged networks. In the everyday state of affairs, queue phenomena are observed in the several situations like the health clinic, railway reservation system, automobile laundry centre, bank cash counter, call centre, etc. Similarly, the phenomenon of congestion is ascertained in the telephone network, computer network, communication systems and the Internet wherever nonstop enhancements need to be created to stay up with the quickly growing demand. The subsistence of these adverse clogging effects has lead toward the improvement of queuing theory-based statistical models. Therefore, these queues based statistical models answering to optimising queries corresponding to the way for assigning resources in converged optical and wireless networks. During this paper, a review on the role of the queuing model in wireless & optical communication is presented that concentrate on the present and future aspects of research.     

Modelling of spatio–temporal interaction for video quality assessment

Video services have appeared in the recent years due to advances in video coding and convergence to IP networks. As these emerging services mature, the ability to deliver adequate quality to end-users becomes increasingly important. However, the transmission of digital video over error-prone and bandwidth-limited networks may produce spatial and temporal visual distortions in the decoded video. Both types of impairments affect the perceived video quality. In this paper, we examine the impact of spatio–temporal artefacts in video and especially how both types of errors interact to affect the overall perceived video quality. We show that the impact of the spatial quality on overall video quality is dependent on the temporal quality and vice-versa. We observe that the introduction of a degradation in one modality affects the quality perception in the other modality, and this change is larger for high-quality conditions than for low-quality conditions. The contribution of the spatial quality to the overall quality is found to be greater than the contribution of the temporal quality. Our results also indicate that low-motion talking-head content can be more negatively affected by temporal frame freezing artefacts than other general type of content with higher motion. Based on the results of a subjective experiment, we propose an objective model to predict overall video quality by integrating the contributions of a spatial quality and a temporal quality. The non-linear model shows a very high linear correlation with subjective data.     

Overhead line in a protected floodplain woodland – "Extended Ecology" as basis for OHL planning and maintenance

The construction of overhead lines, their maintenance, refurbishment and renewal are nowadays seen in a different light than before. Today environmental aspects are among the most challenging aspects of high concern – in every part of life. The society's point of view has changed during the last 20 years – nature and environment are now of mayor interest. In addition to techniques and science, the perception of landscape, fauna and flora is taken into consideration during the planning process of an OHL. We call this "Extended Ecology". The project presented here for the replacement of a 220 kV overhead line which will run along an existing OHL corridor through a floodplain woodland in a nature protective zone is a good example for the new approach. To create harmony between ecology and economy is a precondition of the project. The responsible and careful treatment of the existing OHL corridor during the last few years has resulted in an improvement of conditions. In only a few years the number of endangered species living in these areas and listed on the "Red Data Lists" has increased from 23 to 40. The city of Linz is the capital of the Region "Upper Austria" and is Austria's centre for heavy metal industry with European dimensions (e.g.VOEST Alpine). The city is also well-known for advanced technologies and recently for modern arts (ars electronica, Klangwolke, European Cultural Capital 2009). The expansion of the industry and of dwelling areas reduced and endangered the natural environment; therefore – and as a logical compromise – several areas were nominated as natural protective zones. Existing overhead lines run through some of these, and some of them need to be uprated. Two parallel 110 kV OHL run through the protected floodplain woodland of "Donau-Traun-Auen". One of them was built in the 1940ies and needs to be rebuilt as a 220 kV line. Since 2006 ecological treatment techniques have been in practice in these corridors. This area originally showed a pattern of degraded nutrient-poor alluvial meadows, rich in invasive neophytes, fragments of semi-dry calcareous-grassland, tiny large sedge or reed beds in moist depressions and large short rotation coppice woodland. During the last years additional ecological compensation measures have been implemented: ponds have been created and open gravel areas generated by construction measures have been re-vegetated taking into account the soil seed bank and using proved techniques of nature conservation. Significant success can be reported after only a few years of subtle treatment techniques aimed at optimal development of target vegetation. The typical composition of plant species could be restored in core areas of nutrient-poor alluvial meadows. The number of species enumerated in "Red Data Lists" has increased from 23 to 40, including highly endangered plants demanding moderate disturbance regimes. If ecological treatment is continued, further increase of environmental conservation value in the corridor can be expected.     

Investigation and design of high efficiency carbazole-based sensitizers for solar cells: Effect of the nature and length of π-linker

Three synthesized and five new designed carbazole-based organic dye sensitizers before and after bonding to the TiO₂ are theoretically investigated by density functional theory and time-dependent density functional theory methods. The influences of inserting different groups between donor and acceptor and augmenting π-spacers on the performance are explored by optimized geometries, electronic structures, simulated absorption spectra, and other parameters. The efficiency of all dyes as sensitizers in dye-sensitized solar cells is evaluated by the key parameters, including HOMO–LUMO energy gap, distance of charge transfer upon excitation from the ground to excited state, light-harvesting efficiency, injection driving force, and total reorganization energy related with the short-circuit current density and open-circuit photovoltage. It has been testified that both the nature and the number of π-linker units are important factors for the performance of dye-sensitized solar cells.     

Users’ Preferences for Smart Home Automation – Investigating Aspects of Privacy and Trust

Smart home automation provides residents with relief and convenience in everyday life and allows for self-determined aging in place. Yet, market penetration is offset by user concerns related to privacy and trust issues: With increasing system complexity, users may perceive a loss of control and fear technical unreliability. While barriers to acceptance in terms of privacy and trust are well understood when considered separately, they are hardly investigated in conjunction so far. We conducted a quantitative study using Adaptive Choice-Based Conjoint Analysis via an online questionnaire. We explored how aspects of privacy and trust determine the willingness to use smart homes from the perspective of (future) users (n = 137, 18 to 64 years of age), and also with respect to the level of automation and application field. Results show that semi-automated systems are rather preferred than fully automated smart home technology. The perceived reliability of automation is the most important acceptance determinant, followed by the location of data storage. Whereas the awareness to use (e.g., recommendations), the type of data, and application field are less important factors for the overall willingness to use smart homes. Findings inform scientists in the field of human-automation interaction and technical developers of smart home automation for technology innovation adapted to user needs.     

Modelling the current—voltage characteristic of a fluorescent lamp for computer-aided design

An empirical formula is presented for the voltage-current characteristics of a fluorescent lamp. The three parameters of the formula can easily be obtained from the measured characteristics of the fluorescent lamp without recourse to conventional curve-fitting techniques. By using this formula the analytical study of electronic circuits incorporating fluorescent lamps can be simplified.     

Coverage planning for optimizing HSDPA performance and?controlling R99 soft handover

Coverage planning is an important engineering task in deploying UMTS networks implementing both high speed downlink packet access (HSDPA) and Release 99 (R99) services. Coverage planning amounts to determining the cell coverage pattern by means of setting the common pilot channel (CPICH) power of the cells. A conventional strategy is to uniformly allocate a proportion of the total power to CPICH. In this paper, we develop mathematical modeling and optimization approaches to bring the benefit of power saving enabled by optimizing non-uniform CPICH to enhance HSDPA performance, while preserving a desired degree of soft handover (SHO) for R99. The study focuses on HSDPA performance at cell edges, where data throughput is typically low. An integer linear programming model is developed for the resulting optimization problem. The model admits optimal or near-optimal planning solutions for relatively small networks. Solution algorithms based on local search and repeated local search are developed. These algorithms are able to perform the optimization for large-scale networks time-efficiently. Experimental results for both synthesized networks as well as instances originating from real planning scenarios demonstrate the benefit of our optimization approach.     

ARMOR – A system for adjusting repair and media scaling for video streaming

To optimize scarce network resources and present the highest quality video, streaming video systems need adapt to the video content as well as the network conditions. This paper presents ARMOR, a video streaming system that dynamically adjusts repair and media scaling to meet current video and network conditions. In order to adapt effectively, ARMOR, and any dynamic video adaptation system, needs to predict the video quality as perceived by end users over the range of scaling and repair choices. Thus, this paper first proposes a novel video quality metric called distorted playable frame rate that provides estimation of user perceptual quality considering temporal and quality degradations. Comprehensive user studies show distorted playable frame rate is more accurate than other video quality metrics. Analytic experiments with distorted playable frame rate and the ARMOR optimization algorithm illustrate the predictive power of the metric in a dynamic, streaming video system. Lastly, implementation and experiments of a complete, fully-functioning ARMOR system show the effective practicality of the proposed approach.     

Joint Phase and Amplitude Modelling Using a Finite-State Markov Chain for η–µ Fading Channels

Wireless Personal Communications - The η–µ fading distribution is used for better representation of small scale variations of the faded signal in Non Line-Of-Sight conditions. In...     

A model for concept evaluation in design––an application to mechatronics design of robot grippers

In this paper, an approach for the modelling of the evaluation process in the conceptual design phase is presented. During the design process, the generated candidate solutions are evaluated. The evaluation is achieved by calculating a score that is based on specific criteria that are presented as elements of a vector. Weight factors are applied to highlight the importance of each criterion. The formulation of the evaluation score is based on t-norm and averaging operators with the assumption that the universe of discourse of criteria is [0,1]. A discussion of the meaning of these operators and a comparative study of them is presented. As an application, the mechatronics design of robot grippers for handling fabrics is analysed. The elements of the mechatronics index are presented in terms of flexibility, intelligence and complexity. This index is formulated using the variety of the t-norms and averaging operators to show the weaks and strengths of each of them.     

Digital broadcasting – Challenges and opportunities for European community radio broadcasters

Access to broadcast infrastructure is vital for community radio services, however the switch-over from analogue to digital, as envisaged by European policy-makers, creates challenges for such stations. In this article, we will set out the general environment within which the transition to digital is occurring, illustrate the current state of the digital migration debate, identify potential difficulties for community radios, but also highlight opportunities that digital technologies may provide.     

An admittance-controlled wheeled mobile manipulator for mobility assistance: Human–robot interaction estimation and redundancy resolution for enhanced force exertion ability

In this paper, a novel robotic assistive system (RAS) for mobility assistance of elderly adults is developed based on admittance control with force exertion ability enhancement (FEAE) of a wheeled mobile manipulator (WMM). The RAS can provide supportive force in the vertical direction and be guided by the user with a limited horizontal plane ability. An admittance controller is adopted to realize compliant behaviour between the end-effector and the user, enabling different admittance performances in different directions without requiring the complex system dynamics. The end-effector force needed by the controller is estimated by employing a nonlinear disturbance observer, avoiding the need for pricey force/torque (F/T) sensor. Meanwhile, with consideration of the limited joint torque output, the FEAE approach is implemented in the null-space of the WMM, which can make the system exert more Cartesian force in a given direction with consideration of Cartesian stiffness requirement using the same joint torque limitation through kinematic reconfiguration. Thus, it improves the capability of the system in realizing the desired admittance requirement. The advantages and effectiveness of the proposed approach are experimentally demonstrated with a 4-wheel omnidirectional mobile manipulator.     

CSA-doped PANI/TiO2 hybrid BHJ solar cells – Material synthesize and device fabrication

In this study, camphorsulfonic acid (CSA) doped polyaniline (PANI) synthesized by oxidative polymerization and titanium-di-oxide (TiO₂) nanoparticles synthesized by sol-gel were solution blend in a mixed solvent of 1:1 m-cresol and chloroform to fabricate hybrid bulk heterojunction (BHJ) solar cells of structure ITO/PEDOT:PSS/CSA-doped PANI-TiO₂/Al. The effect of TiO₂ weight ratio on the cell performance was investigated by analyzing the structural and optical properties of CSA-doped PANI/TiO₂ hybrid thin films with different TiO₂ ratio. Crystalline structure of TiO₂ nanoparticles, polymer and hybrid thin films were identified by XRD studies and root-like structure of both polymer and hybrid thin films by SEM image. CSA-doped PANI was confirmed as p-type semiconductor through Hall-effect analysis. High absorption coefficient along with PL quenching in hybrid thin film confirms its application in solar cells as photoactive layer. For optimal fabrication conditions, maximum photo conversion efficiency (PCE) of 0.21% was obtained for a device with lower TiO₂ weight ratio. The results show that optimization of absorption intensity of CSA-doped PANI in the visible region of spectrum and morphology of hybrid films will effectively enhance the performance of hybrid solar cells. Error analysis of PCE for all the fabricated solar cells has been reported.     

Modelling and simulation of indirect space vector modulated matrix converter using MATLAB®/Simulink®

This article describes a MATLAB®/Simulink® simulation model which analyses the fundamentals about a direct AC–AC power converter with an important research interest at the moment: the matrix converter (MC). The article is focused on space vector modulation modelling applied to this particular converter. The power circuit model is completely implemented using the power library in Simulink, contributing to the simplicity and clearness of the whole model. MC is modulated using the Indirect Space Vector Modulation (ISVM) model which is implemented and explained step-by-step following the space vector basic theory. The model is flexible about changing the modulation technique, the load or removing the input filter, becoming an effective simulation tool in the first stage of a real implementation. It can also be used in an educational environment to present the basic space vector modulation theory applied to the MC.