Algorithms for Del Pezzo surfaces of degree 5 (construction, parametrization)

It is well known that every Del Pezzo surface of degree 5 defined over a field k is parametrizable over k. In this paper, we give an algorithm for parametrizing, as well as algorithms for constructing examples in every isomorphism class and for deciding equivalence.     

Layered Ceramic Phosphors Based on CaAlSiN3:Eu and YAG:Ce for White Light‐Emitting Diodes

To develop warm‐white light‐emitting diodes via conversion phosphors, blue light‐emitting diodes are generally combined with mixtures of green and red‐emitting phosphor powders. Generally, the phosphors are provided by resin embedded particle dispersions. Such resin‐based solutions cause several drawbacks with respect to LED lifetime and quality. Therefore, it has been investigated whether the red‐emitting nitride phosphor CaAlSiN₃:Eu and the green‐emitting oxidic phosphor YAG:Ce can be cofired to layered ceramic composites. The shrinkage behavior and the composition of the interface in dependence of sintering temperature and the effect of interdiffusion processes at the interface on the luminescence properties were investigated. The formation of secondary phases at the interface in the cofired structures was found to limit the phosphor functionality for the nitride‐based CaAlSiN₃:Eu in such composite ceramics. To counteract this, sacrificial interlayers were introduced to produce multilayered ceramics comprising CaAlSiN₃:Eu and YAG:Ce for LED lighting applications. It is shown for the first time, that it is possible to sinter layered CaAlSiN₃:Eu and YAG:Ce composite ceramics in a pressureless process at moderate sintering temperatures if one uses thin‐film passivated interfaces to reduce luminescence‐disturbing diffusion phenomena. These results demonstrate that diffusion barriers can be suitable means to obtain layered ceramic composites comprising CaAlSiN₃:Eu and YAG:Ce in a pressureless sintering process with good optical properties.     

Space extreme design

This paper is an introduction to the following five articles, that have been conceived together as one chapter on habitability consideration for outer space habitations. Those contributions are made from authors in different fields, cultures and countries working with the Extreme-Design.eu research group. Projects, theories and requirements are referred to the context of outer space habitats, where for the love of knowledge, human beings are living under extreme condition. The group purpose is to apply holistic approach (using both scientific and humanity discipines) towards space habitat design to support human cultural experience and improve technical reliability. Space Anthropology, Space Design, Space Art and Space Psychology are the established disciplines here considered to have a bearing on astronaut reliability. With multidisciplinary contributions, natural design philosophy- and human-centred design, these papers aim of collecting a range of solutions and innovative ideas on how to increase habitability in space.     

A NFC-based pervasive solution for city touristic surfing

Context-aware and pervasive computing applications have increased their number during the last decade, thanks to the development of new communication and mobile technologies. These applications cover a wide spectrum of problems, sectors, scenarios, and environments that aim to build smart environments supporting many kinds of human interactions. Tourism is an important economic sector for many cities and countries and therefore a research area where the development of ubiquitous applications is having a great interest. In this paper, we propose a solution oriented to help the user to find the location of interest points within the city and navigate through them. In this work, we propose the use of mobile phones with the near-field communication technology incorporated and Smart Posters disseminated along the city. Indoor and outdoor locations and navigation are allowed, “where is it?”, “what is it?”, “where am I?”, “what is there around me?” and the remaining hits of locations and navigation paradigms are supported by an easy, cheap, and context-awareness system without the need of hard tasks to the user related to system installation or tailoring.     

Non‐diagonal MIMO QFT controller design reformulation

This paper presents a reformulation of the full‐matrix quantitative feedback theory (QFT) robust control methodology for multiple‐input–multiple‐output (MIMO) plants with uncertainty. The new methodology includes a generalization of previous non‐diagonal MIMO QFT techniques; avoiding former hypotheses of diagonal dominance; simplifying the calculations for the off‐diagonal elements, and then the method itself; reformulating the classical matrix definition of MIMO specifications by designing a new set of loop‐by‐loop QFT bounds on the Nichols Chart, which establish necessary and sufficient conditions; giving explicit expressions to share the load among the loops of the MIMO system to achieve the matrix specifications; and all for stability, reference tracking, disturbance rejection at plant input and output, and noise attenuation problems. The new methodology is applied to the design of a MIMO controller for a spacecraft flying in formation in a low Earth orbit. Copyright © 2008 John Wiley & Sons, Ltd.     

The impact of an innovative instructional intervention on the acquisition of oral presentation skills in higher education

The present study focuses on the design and development of an instructional approach to develop oral presentation skills. The theoretical base builds on the social cognitive perspective, and self-regulated learning. The aim of the study is to investigate whether the design of a multimedia-based instructional format - comprising of a standardised multimedia instruction, practical activities and feedback - will enhance oral presentation skills. In the study, the differential effect of three ‘modes of feedback’ on performance has been researched. The results reveal that oral presentation skills did improve significantly after the instruction. The multimedia nature of the design was favoured by all participants. In contrast, no significant impact of feedback was found. Nevertheless, feedback proved to be a useful process that was highly welcomed by participants.     

Mining hot calling contexts in small space

Calling context trees (CCTs) associate performance metrics with paths through a program's call graph, providing valuable information for program understanding and performance analysis. In real applications, however, CCTs might easily consist of tens of millions of nodes, making them difficult to analyze and also hurting execution times because of poor access locality. For performance analysis, accurately mining only hot calling contexts may be more useful than constructing an entire CCT with millions of uninteresting paths, because the distribution of context frequencies is typically very skewed. In this article, we show how to exploit this property to considerably reduce the CCT size, introducing a novel runtime data structure, called hot CCT (HCCT), in the spectrum of representations for interprocedural control flow. The HCCT includes only hot nodes and their ancestors in a CCT and can be constructed independently from it by using fast, space‐efficient algorithms for mining frequent items in data streams. With this approach, we can distinguish between hot and cold contexts on the fly while obtaining very accurate frequency counts. We show, both theoretically and experimentally, that the HCCT achieves a similar precision as the CCT in a space that is several orders of magnitude smaller and roughly proportional to the number of hot contexts. Our approach can be effectively combined with previous context‐sensitive profiling techniques, as we show for static bursting. We devise an implementation as a plug‐in for the gcc compiler that incurs a slowdown competitive with the gprof call‐graph profiler while collecting finer‐grained profiles. Copyright © 2015 John Wiley & Sons, Ltd.     

Sulfur-substituted and α-methylated fatty acids as peroxisome proliferator-activated receptor activators

FA with varying chain lengths and an α-methyl group and/or a sulfur in the β-position were tested as peroxisome proliferator-activated receptor (PPAR)α,-δ(β), and-γ ligands by transient transfection in COS-1 cells using chimeric receptor expression plasmids, containing cDNAs encoding the ligand-binding domain of PPARα,-δ, and-γ. For PPARα, an increasing activation was found with increasing chain length of the sulfur-substituted FA up to C₁₄-S acetic acid (tetradecylthioacetic acid=TTA). The derivatives were poor, and nonsignificant, activators of PPARδ. For PPARγ, activation increased with increasing chain length up to C₁₆-S acetic acid. A methyl group was introduced in the α-position of palmitic acid, TTA, EPA, DHA, cis9,trans11CLA, and trans10,cis12 CLA. An increased activation of PPARα was obtained for the α-methyl derivatives compared with the unmethylated FA. This increase also resulted in increased expression of the two PPARα target genes acyl-CoA oxidase and liver FA-binding protein for α-methyl TTA, α-methyl EPA, and α-methyl DHA. Decreased or altered metabolism of these derivatives in the cells cannot be excluded. In conclusion, saturated FA with sulfur in the β-position and increasing carbon chain length from C₉−S acetic acid to C₁₄−S acetic acid have increasing effects as activators of PPARα and-γ in transfection assays. Furthermore, α-methyl FA derivatives of a saturated natural FA (palmitic acid), a sulfur-substituted FA (TTA), and PUFA (EPA, DHA, c9,t11 CLA, and t10,c12 CLA) are stronger PPARα activators than the unmethylated compounds.     

A capacitance and optical method for the static and dynamic characterization of micro electro mechanical systems (MEMS) devices

As the micro technology field expands, the need of simple and standardized procedures to precisely evaluate device functionality, realibility and quality of micro electro mechanical systems devices increases. In this paper the application of two empirical methods suitable for the static and the dynamic characterization of micrometersized structures is proposed. The first methodology is based on capacitance measurements and finds simple application in case of comb-finger actuated devices. The second one is based on the Doppler phenomenon combined with laser optical interferometry allowing the characterization of a wide range of structures. The methodologies are applied to a reliability test structure specifically designed at STMicroelectronics for studying the fatigue behaviour of the structural material involved in the fabrication of their commercial products. This case of study highlights how the techniques may be coupled to usual design approaches for completing and verifying the information given by theory and simulations; thus improving the entire development cycle.