Perceptual depth compression for stereo applications

Conventional depth video compression uses video codecs designed for color images. Given the performance of current encoding standards, this solution seems efficient. However, such an approach suffers from many issues stemming from discrepancies between depth and light perception. To exploit the inherent limitations of human depth perception, we propose a novel depth compression method that employs a disparity perception model. In contrast to previous methods, we account for disparity masking, and model a distinct relation between depth perception and contrast in luminance. Our solution is a natural extension to the H.264 codec and can easily be integrated into existing decoders. It significantly improves both the compression efficiency without sacrificing visual quality of depth of rendered content, and the output of depth‐reconstruction algorithms or depth cameras.     

On the market of wind with hydro-pumped storage systems in autonomous Greek islands

In autonomous islands, the wind penetration is restricted due to technical reasons related with the safe operation of the electrical systems. The combined use of wind energy with pumped storage (WPS) is considered as a mean to exploit the abundant wind potential, increase the wind installed capacity and substitute conventional peak supply. In this paper, the experience gained from the analysis of WPS in three specific islands is used towards the estimation of the WPS market in autonomous Greek islands. Parameterized diagrams and a methodology towards the pre-dimensioning and initial design of the WPS are proposed and used towards the estimation of the market in autonomous Greek islands. The objective is to make an initial general prefeasibility study of WPS prospects in the autonomous Greek islands. Results show that there is a significant market for WPS in Greece and the development cost of WPS is competitive to the fuel cost of local power stations in autonomous islands.     

Comparison of Four Subjective Methods for Image Quality Assessment

To provide a convincing proof that a new method is better than the state of the art, computer graphics projects are often accompanied by user studies, in which a group of observers rank or rate results of several algorithms. Such user studies, known as subjective image quality assessment experiments, can be very time‐consuming and do not guarantee to produce conclusive results. This paper is intended to help design efficient and rigorous quality assessment experiments and emphasise the key aspects of the results analysis. To promote good standards of data analysis, we review the major methods for data analysis, such as establishing confidence intervals, statistical testing and retrospective power analysis. Two methods of visualising ranking results together with the meaningful information about the statistical and practical significance are explored. Finally, we compare four most prominent subjective quality assessment methods: single‐stimulus, double‐stimulus, forced‐choice pairwise comparison and similarity judgements. We conclude that the forced‐choice pairwise comparison method results in the smallest measurement variance and thus produces the most accurate results. This method is also the most time‐efficient, assuming a moderate number of compared conditions.     

Self‐Regulating Iris Based on Light‐Actuated Liquid Crystal Elastomer

The iris, found in many animal species, is a biological tissue that can change the aperture (pupil) size to regulate light transmission into the eye in response to varying illumination conditions. The self‐regulation of the eye lies behind its autofocusing ability and large dynamic range, rendering it the ultimate “imaging device” and a continuous source of inspiration in science. In optical imaging devices, adjustable apertures play a vital role as they control the light exposure, the depth of field, and optical aberrations of the systems. Tunable irises demonstrated to date require external control through mechanical actuation, and are not capable of autonomous action in response to changing light intensity without control circuitry. A self‐regulating artificial iris would offer new opportunities for device automation and stabilization. Here, this paper reports the first iris‐like, liquid crystal elastomer device that can perform automatic shape‐adjustment by reacting to the incident light power density. Similar to natural iris, the device closes under increasing light intensity, and upon reaching the minimum pupil size, reduces the light transmission by a factor of seven. The light‐responsive materials design, together with photoalignment‐based control over the molecular orientation, provides a new approach to automatic, self‐regulating optical systems based on soft smart materials.     

Affect expression in ECAs: Application to politeness displays

In this paper we present our embodied conversational agent (ECA) capable of displaying a vast set of facial expressions to communicate its emotional states as well as its social relations. Our agent is able to superpose and mask its emotional states as well as fake or inhibit them. We defined complex facial expressions as expressions arising from these displays. In the following, we describe a model based on fuzzy methods that enables to generate complex facial expressions of emotions. It uses fuzzy similarity to compute the degree of resemblance between facial expressions of the ECA. We also present an algorithm that adapts the facial behaviour of the agent depending on its social relationship with the interactants. This last algorithm is based on the theory of politeness by Brown and Levinson (1987). It outputs complex facial expressions that are socially adequate.     

Makespan minimization flowshop with position dependent job processing times—computational complexity and solution algorithms

This paper considers flowshop scheduling problems where job processing times are described by position dependent functions, i.e., dependent on the number of processed jobs, that model learning or aging effects. We prove that the two-machine flowshop problem to minimize the maximum completion time (makespan) is NP-hard if job processing times are described by non-decreasing position dependent functions (aging effect) on at least one machine and strongly NP-hard if job processing times are varying on both machines. Furthermore, we construct fast NEH, tabu search with a fast neighborhood search and simulated annealing algorithms that solve the problem with processing times described by arbitrary position dependent functions that model both learning and aging effects. The efficiency of the proposed methods is numerically analyzed.     

Multi-agent system to support decision-making process in design for recycling

In this paper, the application of multi-agent system to support decision-making process in design for recycling is presented. The design for recycling term is highlighted either as the design problem or from the point of view of regulations. The structure of agent system supporting the designer during the design process is showed. The basis of special kind of product model, that is the extension of standard 3D product model, called recycling-oriented product model, is described. The example results of analysis, based on real household appliance model, are presented.     

The Potential of Al2O3–ZrO2-Based Composites,Formed via CSC Method,in Linear Infrastructure Applications Based on Their Mechanical,Thermal and Environmental performance

Metallurgical and Materials Transactions A - Ceramic-ceramic composites have been prepared using the centrifugal slip casting method (CSC). The method has so far been mainly utilized in making...     

Construction particleboards made from rapeseed straw glued with hybrid pMDI/PF resin

The paper investigates the possibility of manufacturing rapeseed particleboards (RPB) which could be used as construction material in eco buildings. Therefore, single-layer particleboards were produced from rapeseed straw particles glued with mixture of 4.4′-methylenediphenyl isocyanate (pMDI) and phenol–formaldehyde (PF) resins in the weight ratio 70:30 (hybrid pMDI/PF resin). The boards were manufactured with density of 650, 600, 550, 500 and 450 kg/m³. Next, their physico-mechanical properties were determined, i.e. modulus of rupture, modulus of elasticity, internal bond and internal bond after the boil test (V-100) and thickness swelling after 24 h soaking in water. The thermal conduction coefficient (λ) and sorption properties in changeable relative humidity conditions were also determined. Based on the obtained results, it was found that rapeseed straw may be a valuable material used in the production of construction particleboards which meet high strength requirements. Boards with density of 650 kg/m³ meet the requirements of EN 312 standard for type P7 boards. It is also possible to decrease their density to 600 kg/m³ (type P5 boards) and even 550 kg/m³ (type P3 boards). However, rapeseed particleboards are characterized by relatively high values of thickness swelling after 24 h of soaking in water. The weaker resistance to humidity has also been confirmed by tests on sorption and desorption of vapour in changeable relative humidity conditions. Nonetheless, an important advantage of these boards is the fact that they are characterized by better thermal insulation than particleboards.