Heterogeneous networking

In this article, security challenges related to a mobile heterogeneous networking environment, and the general access patterns are discussed. A novel, unified networking architecture that enables secure heterogeneous networking, both in terms of networks and user devices is discussed. A comprehensive security framework providing a generalized authentication scheme using the Extensible Authentication Protocol (EAP) is then presented, by taking into account existing methods for secure network and device access.     

Effect of Ni7+ Ion Irradiation on Structure and Ammonia Sensing Properties of Thermally Oxidized Zinc and Indium Films

ZnO and In2O3 films were prepared by thermal oxidation of vacuum deposited zinc and indium films, respectively onto the glass substrate at 30 C. The fabricated films have been irradiated with 100-MeV Ni7+ ions at different fluences ranging from 5×1011 to 5×1013 ions/cm2. The structural and gas sensing properties of pristine and irradiated films have been discussed. X-ray diffraction (XRD) pattern of pristine and irradiated films reveal that the films are polycrystalline in nature and crystallinity increases after irradiation. In this study, highly porous In2O3 nanorods evolved when being irradiated at a fluence of 5×1013 ions/cm2 while ZnO film shows decrease in number of nanowires. The ammonia sensing performance of the Ni7+ irradiated In2O3 films shows an improvement as compared to its pristine counterpart.     

A real-time distributed algorithm for an aircraft longitudinal optimal autopilot

This paper is concerned with fast and efficient computations for the solution of the two-point boundary-value problem that arises in optimal control of an aircraft longitudinal mode. The solution proposed is implemented on a T800 transputer network using parallel C and is shown to be adequate for real-time control purposes.     

Failure strain as the key design criterion for fracture of natural fibre composites

Natural fibre composites are often considered to be problematic because of the high variability in their mechanical properties. This short communication considers the statistical variation in the two key fracture properties (strain and strength) for data obtained from tests on 785 jute technical fibres. The fibre strength does have high variability, which arises from the difficulty of determining an accurate fibre cross-sectional area (CSA). Failure strain is more consistent as this property is independent of the fibre cross-section. The authors therefore recommend that the use of failure strain as the key design criterion for natural fibre composites would expedite the adoption of these materials in the market.     

A systematic approach to the problem of odour source localisation

Although chemical sensing is far simpler than vision or hearing, navigation in a chemical diffusion field is still not well understood. Biological studies have already demonstrated the use of various search methods (e.g., chemotaxis and biased random walk), but robotics research could provide new ways to investigate principles of olfactory-based search skills (Webb, 2000; Grasso, 2001). In previous studies on odour source localisation, we have tested three biologically inspired search strategies: chemotaxis, biased random walk, and a combination of these methods (Kadar and Virk, 1998; Lytridis et al., 2001). The main objective of the present paper is to demonstrate how simulation and robot experiments could be used conjointly to systematically study these search strategies. Specifically, simulation studies are used to calibrate and test our three strategies in concentric diffusion fields with various noise levels. An experiment with a mobile robot was also conducted to assess these strategies in a real diffusion field. The results of this experiment are similar to those of simulation studies showing that chemotaxis is a more efficient but less robust strategy than biased random walk. Overall, the combined strategy seems to be superior to chemotaxis and biased random walk in both simulation and robot experiment. Christodoulos Lytridis received a BEng degree in electronic and computer engineering, MSc degree in mobile robotics and PhD in Olfactory based navigation for mobile robots from the University of Portsmouth. His research interests include odor-based cooperative navigation, biologically inspired navigational methods, and odor sensors for mobile robots. He is an associate member of the Institution of Electrical Engineering. Endre E. Kadar is a senior lecturer in psychology at the University of Portsmouth. He began his academic career as a theoretical mathematician at the Institute of Hydraulic Planning, working in applied modelling on a variety of problems in engineering. Then he moved to the University of Connecticut to work as a teaching and research assistant and received his PhD in experimental psychology in 1996. His PhD research project has dealt with the problem of ecological foundation of perceptual control of locomotion. After moving to Portsmouth in 1996, his theoretical work provided the basis for a productive collaboration with engineers in robotics. Also, these novel field theoretical ideas have resulted in radically new approaches to exploratory learning and visual control of high speed driving. Application of these approaches has been supported by several ESRC grants. Gurvinder S. Virk graduated with first class honours in electrical and electronic engineering (University of Manchester) and received a PhD in control theory (Imperial College, London). He has followed an academic career working at Sheffield City Polytechnic, Universities of Southampton, Sheffield and Bradford, Portsmouth and is now professor of control and robotics at the University of Leeds. His main research interests include robotics, building and energy management systems, and application of advanced model-based control systems. He has held several grants from national and European sources, as well as industry (the total value of ￡11M). He has more then 200 publications, including four books. He coordinated the European thematic network CLAWAR and has been involved in developing robots for exploring volcanic environments, inspection of highway bridges and dams, and biomedical applications. He is chairman of the ISO TC184/SC2 Advisory Group on Standards for mobile service robots. He is Fellow of the Institution of Engineering and Technology, Fellow of the Chartered Institution of Building Services Engineers, Fellow of the Institution of Applied Mathematics and Its Applications. He is Charted Engineer and a Charted Mathematician. He has been awarded the Freedom of the City of London for his work in promoting Information Technology.     

In vitro batch fecal fermentation comparison of gas and short-chain fatty acid production using "slowly fermentable" dietary fibers

Abstract: Sustained colonic fermentation supplies beneficial fermentative by‐products to the distal colon, which is particularly prone to intestinal ailments. Blunted/delayed initial fermentation may also lead to less bloating. Previously, we reported that starch‐entrapped alginate‐based microspheres act as a slowly fermenting dietary fiber. This material was used in the present study to provide a benchmark to compare to other “slowly fermentable” fibers. Dietary fibers with previous reports of slow fermentation, namely, long‐chain inulin, psyllium, alkali‐soluble corn bran arabinoxylan, and long‐chain β‐glucan, as well as starch‐entrapped microspheres were subjected to in vitro upper gastrointestinal digestion and human fecal fermentation and measured over 48 h for pH, gas, and short‐chain fatty acids (SCFA). The resistant fraction of cooked and cooled potato starch was used as another form of fermentable starch and fructooligosaccharides (FOS) served as a fast fermenting control. Corn bran arabinoxylan and long‐chain β‐glucan initially appeared slower fermenting with comparatively low gas and SCFA production, but later fermented rapidly with little remaining in the final half of the fermentation period. Long‐chain inulin and psyllium had slow and moderate, but incomplete, fermentation. The resistant fraction of cooked and cooled potato starch fermented rapidly and appeared similar to FOS. In conclusion, compared to the benchmark slowly fermentable starch‐entrapped microspheres, a number of the purported slowly fermentable fibers fermented fairly rapidly overall and, of this group, only the starch‐entrapped microspheres appreciably fermented in the second half of the fermentation period. Practical Application: Consumption of dietary fibers, particularly commercial prebiotics, leads to uncomfortable feelings of bloating and flatulence due to their rapid degradation in our large intestine. This article employs claimed potential slowly fermenting fibers and compares their fermentation rates with a benchmark slow fermenting fiber that we fabricated in an in vitro simulation of the human digestive system. Results show a variety of fermentation profiles only some of which have slow and extended rate of fermentation.     

Understanding the relationship between intensity and gratifications of Facebook use among adolescents and young adults

Facebook is a well-known computer-mediated communication platform considered popular among adolescents and young adults. New media scholars have coined the term “intensity of Facebook use” (IFU) for the concept that measures the emotional and affective attitude towards Facebook use among young people. IFU is an important service use concept that has been positively linked with the different psychosocial outcomes of student well-being. However, only a limited amount of the prior literature has investigated the relationship between IFU and different Facebook uses and gratifications (U&G). The existing literature suggests inconsistent findings with a sole emphasis on young adults. To address these gaps, the present study has investigated the differential role of different Facebook U&G among adolescents and young adults in predicting IFU. A total of three cross-sectional data sets (N = 373, 107, 105) represented adolescents and university-attending young-adult Facebook users. The study results suggest that process U&G do and content U&G do not play any significant role in predicting IFU. Adolescents and young adults differ in their sought Facebook U&G. In addition to this, cultural differences were observed in the sought Facebook U&G and their differential role in predicting IFU.     

Effect of metakaolin on the near surface characteristics of concrete

Results on an investigation dealing with the effect of metakaolin (MK) on the near surface characteristics of concrete are presented in this paper. A control concrete having cement content 450 kg/m³ and w/c of 0.45 was designed. Cement was replaced with three percentages (5, 10, and 15%) of metakaolin weight. Tests were conducted for initial surface absorption, sorptivity, water absorption and compressive strength at the ages of 35, 56, and 84 days. Test results indicated that with the increase in MK content from 5 to 15%, there was a decrease in the initial surface absorption, decrease in the sorptivity till 10% metakaolin replacement. But at 15% MK replacement an increase in sorptivity was observed. All mixtures showed low water absorption characteristic i.e. less than 10%. Compressive strength shared an inverse relation with sorptivity. Higher MK replacements of 15% are not helpful in improving inner core durability, even though it helps in improving surface durability characteristics.     

Failure analysis of heat exchanger fluid vapor phase vent lines in a Polyester plant

A Polyester plant is using Proprietary heat exchange fluids (26.5% biphenyl, 73.5% diphenyloxide). The plant hot condensate tank, condensate feed tank, and heat exchanger vapor phase dead end and ventable lines (ASTM 106 Grade B) with isolation valves were suffering frequent leakages with severe gouging and pitting corrosion. Lustrous (shiny) coke deposit was prominent inside the cut sections due to coke formation by low boiler products. Some adhered brown iron oxide (rust) deposits were also visible. A sludge sample was analyzed by XRD which revealed that carbon was the major constituent with γ-Maghemite-C (an iron oxide) as second mineral in order of abundance. The failure was diagnosed as severe localized corrosion and gouging at temperatures of about 200 °C and 53 psi by non-condensable low boilers decomposed corrosive products. The remedy was suggested which has been validated over the 2 years trouble free performance.     

Neuro-fuzzy-based solar cell model

This work describes a hybrid soft-computing modeling technique that facilitates the modeling of newly installed solar cells, or solar cells with few historical measured data, over a range of expected operating conditions. The technique uses neuro-fuzzy models to predict solar cell short-circuit current and open-circuit voltage, followed by coordinate translation of a measured current-voltage response. The model can be extended beyond the bounds of measured data by incorporating a priori knowledge derived from theory and manufacturer's data. The solar cell model is developed and validated against measured data. The model requires fewer data than pure neural network models, and matches measured data more accurately than conventional solar cell models.