An analysis of social interaction between novice older adults when learning gesture-based skills through simple digital games

Universal Access in the Information Society - This paper reports three exploratory empirical studies with older adults that had little or no prior experience with interactive technologies. The...     

Opportunities and challenges for a sustainable energy policy in SE Europe: SE European Energy Community Treaty

Energy demand continues to increase in turn raising concerns about energy supply. In this paper, the author has tried to systematize the role of the energy sector in South Eastern (SE) Europe in the context of the European energy policy process. This should make the energy sector in SE Europe more visible and open to substantial activities and appropriate funding. This is important to assure its full alignment with the European energy policy process, and in so doing, make it less fragile. According to the SE European Energy Community Treaty, parties to the Treaty are obliged to implement reforms in the energy and environmental sector in accordance with the European Union's respective policy.This paper raises awareness of the environmental requirements that have been set, of renewable energy and its implementation, at the same time pointing out that the response in SE Europe has been at a low level. It is believed that this paper could draw attention to the existing problems and could contribute to the establishment of a common integrated energy market in SE Europe and the EU.     

The new screening characteristics of strongly non-ideal and dusty plasmas. Part 3: Properties and applications

The physical sense and the properties of a group screening parameters which are determined in the previous papers (Part 1 and Part 2) for single- and two-component systems is discussed in this paper. On the base of data from the mentioned papers are determined two new characteristic lengths which complete a new hierarchy system of screening lengths in plasma. It was shown that the methods developed in Part 1 and Part 2 generates results which are applicable to the strongly non-ideal gaseous and dusty plasmas, and manifest a very good agreement with the existing experimental data.     

On designing usable and secure recognition-based graphical authentication mechanisms

In this article we present the development of a new, web-based, graphical authentication mechanism called ImagePass. The authentication mechanism introduces a novel feature based on one-time passwords that increases the security of the system without compromising its usability. Regarding usability, we explore the users’ perception of recognition-based, graphical authentication mechanisms in a web environment. Specifically, we investigate whether the memorability of recognition-based authentication keys is influenced by image content. We also examine how the frequency of use affects the usability of the system and whether user training via mnemonic instructions improves the graphical password recognition rate. The design and development process of the proposed system began with a study that assessed how the users remember abstract, face or single-object images, and showed that single-object images have a higher memorability rate. We then proceeded with the design and development of a recognition-based graphical authentication mechanism, ImagePass, which uses single-objects as the image content and follows usable security guidelines. To conclude the research, in a follow-up study we evaluated the performance of 151 participants under different conditions. We discovered that the frequency of use had a great impact on users’ performance, while the users’ gender had a limited task-specific effect. In contrast, user training through mnemonic instructions showed no differences in the users’ authentication metrics. However, a post-study, focus-group analysis revealed that these instructions greatly influenced the users’ perception for memorability and the usability of the graphical authentication. In general, the results of these studies suggest that single-object graphical authentication can be a complementary replacement for traditional passwords, especially in ubiquitous environments and mobile devices.     

The new screening characteristics of strongly non-ideal and dusty plasmas. Part 2: Two-component systems

A new model method for describing of the electrostatic screening in two-component systems (electron-ion plasmas, dusty plasmas, electrolytes, etc) is developed. The method is applicable to the systems of higher non-ideality degree. The expressions for all the screening parameters introduced in the previous paper (Part 1) of this work, as well as for an additional parameter characteristic for multi-component systems, are obtained. All these parameters are presented in a simple analytic form suitable for operative laboratory usage, especially for theoretical interpretation of experimental data. Published in Russian in Teplofizika Vysokikh Temperatur, Vol. 47, No. 1, 2009, pp. 5–16 The paper is printed as submitted by the authors and edited by the Editorial Board.     

The new screening characteristics of strongly non-ideal and dusty plasmas. Part 1: Single-component systems

In this paper a new model method for describing of the electrostatic screening in single-component systems which is free of Debye-Hückel’s non-physical properties is presented. The method is appropriate for the determination of screening parameters in the case of the systems of higher non-ideality degree. The obtained screening characteristics are presented in a simple analytic form. The presented results make basic elements of a method for determination of screening characteristics in dense two-component plasmas, which are discussed in following papers. Published in Russian in Teplofizika Vysokikh Temperatur, vol. 46, No. 6, 2008, pp. 805–813. The text was submitted by the authors in English.     

Thermodynamic Analysis of the Metastable Regions for the AI2O3-SiO2 System

The paper offers a short review of investigations conducted on the Al₂O₃-SiO₂ system, particularly from the point of view of an appearance of immiscibility gaps, below the liquidus temperatures. Based on theoretical criteria and using the data along the liquidus curves (for mullite and corundum), this investigation suggests immiscibility regions at both ends of the phase diagram. That is, it defines the Margules polynomials for calculation of the activity coefficients necessary for determining the Gibbs energy of mixing. Obtained results are in good agreement with the results reported by Risbud and Pask and other investigators who have found immiscibility gaps at rather high temperatures.     

Physical structure of phenolaniline–formaldehyde resol resin and its kaolin–filled phenoplasts

An investigation of the physical structure of samples of phenoaniline–formaldehyde resol resin in uncured and cured state, and of its phenoplasts containing different ratios of kaolin filler, was made with the aid of electron microscope pictures. The uncured and cured resin consists of microglobules of a size of 40–80 Å, which agglomerate to form larger-sized globules of various dimensions. After a mathematical elaboration of the results of a large number of measurements, it was established that the diameters of the globules are casual values distributed in accordance with the normal (Gaussian) law. Both in the resin and in the kaolin-filled phenoplasts (at a rate of 25 to 47 vol-%), after curing at 170–180°C and a pressure of 300 kg/sq cm, the mean diameter of the observed globules was of a rather steady value and remained within the limits of 230–240 Å (with a standard deviation of 30–40 Å). A method was elaborated of determining the mean thickness of the adsorption coating of the resin on the filler particles. Calculations show that in the filling interval we have chosen, the thickness of the absorption coating is not below 1.8–0.6 times the mean thickness of the globules.     

Applicability of the redlich-kwong equation of state and its modifications to polar gases

The constants of the Redlich-Kwong equation of state were optimized for each available isotherm using the experimental P-v-T data of nonpolar, slightly