Context-aware service engineering: A survey

Context constitutes an essential part of service behaviour, especially when interaction with end-users is involved. As observed from the literature, context handling in service engineering has been during recent years a field of intense research, which has produced several interesting approaches. In this paper, we present research efforts that attempt mainly to decouple context handling from the service logic. We enumerate all context management categories, but focus on the most appropriate for service engineering, namely source code level, model-driven and message interception, taking also into account the fact that these have not been dealt with in detail in other surveys. A representative example is used to illustrate more precisely how these approaches can be used. Finally, all three categories are compared based on a number of criteria.     

Dynamic mechanical properties of polymer-fluid systems: characterization of poly(2-hydroxyethyl methacrylate) and poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) hydrogels

The complex shear moduli of crosslinked poly(2-hydroxyethyl methacrylate) and poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) hydrogels were measured as a function of water content, temperature and frequency using dynamic mechanical spectroscopy. The effect of increasing water content on both the storage and loss moduli is to lower the temperatures at which mechanical transitions occur. There is a significant decrease in the storage moduli and increase in the loss moduli dispersions with increasing water content. These data could be well correlated by a multiple-mechanism, time-temperature superposition procedure. Between 2% and 28% water content in the copolymer sample, the relaxation spectra and shift function characterizing the glassy-rubbery state transition become independent of water content when properly referenced to the observed transition temperature. At lower temperatures where the β transition occurs, the mechanical viscoelastic spectra depend much more strongly on water content although the shift factors collapse to a single curve when referenced to the observed β transition temperature.     

Optimization techniques in molecular structure and function elucidation

This paper discusses recent optimization approaches to the protein side-chain prediction problem, protein structural alignment, and molecular structure determination from X-ray diffraction measurements. The machinery employed to solve these problems has included algorithms from linear programming, dynamic programming, combinatorial optimization, and mixed-integer nonlinear programming. Many of these problems are purely continuous in nature. Yet, to this date, they have been approached mostly via combinatorial optimization algorithms that are applied to discrete approximations. The main purpose of the paper is to offer an introduction and motivate further systems approaches to these problems.     

Effect of marinating and vacuum storage at 6 °C on the fate of chemical, microbial and sensory quality indices of echinoid gonads Paracentrotus lividus Lamark, 1816

Chemical, microbial and sensory quality indices of raw and marinated sea urchin Paracentrotus lividus Lamark, 1816, were determined. Marinades were prepared using three different formulations and stored over a 75-day period at 6 °C, under vacuum and air (control) packaging conditions. Significant differences were found between chemical (pH, moisture, ash, NaCI, ammonia and lactic acid), microbial [pseudomonads (Ps), lactic acid bacteria (LAB) and yeast–moulds] and sensory analysis of three different marinated groups ( P  <   0.05) during the storage period. The marinating process did not lead to significant differences in fatty acid, protein, fat and carbohydrate contents relative to raw sample. A notable decrease of the ω-3 per ω-6 ratio after marinating and during storage in both packages was observed. Ammonia concentration changes were found to be useful as index of freshness and decomposition of roe in storage. Shelf life of roe marinades at 6 °C was found to be 75 and 60 days under vacuum and air storage conditions respectively.     

Zero-Forcing Successive Decoding Under Nakagami-<Emphasis Type="Italic">m</Emphasis> Fading Channels

In this paper, the performance of a multiuser distributed spatial multiplexing system is analytically investigated. The system operates under a Nakagami-m fading environment. All the users, equipped with single antennas, are simultaneously transmitting their streams to a multi-antenna receiver. Zero-forcing is applied along with successive interference cancellation as a means for efficient detection of the received streams. New exact closed-form expressions with regards to some important performance metrics, namely, outage probability and ergodic capacity of each stream are presented. Both the analytical expressions and the simulation results show the impact of channel severity and scale of antenna array to the overall system performance. A particular emphasis on the scenario of the emerging massive multiple input-multiple output systems is provided.     

Optimized techniques for the extraction of grape allergens appropriate for in vivo and in vitro testing and diagnosis

Standardized allergen extracts are needed for diagnosis and therapy purposes. For grapes, standardization is hampered by low protein and high tannin and pectin concentrations. The aim of the current study was to develop an optimized method for the extraction of grape proteins and possibly extend this to other fruits. Several existing or modified extraction methods were compared by means of protein concentration determination, SDS-PAGE, immunoblotting and radioallergosorbent test (RAST). An optimized extraction protocol was obtained in which we combined a high concentration of plant tissue, a concentrated, enriched and neutral buffer able to remove sugars and keep proteins soluble and a bivalent buffer for pectin removal. Both the quantitative (protein concentration) and qualitative parameters (SDS-PAGE protein patterns and IgE reactivity) were compared to standard protocols and commercial extracts used as diagnostic tools in the clinical practice. This method proved to be the most efficient mainly compared to the standard Bj?rksten protocol in extracting the low molecular weight proteins, including the major grape allergen (lipid transfer protein, Vit v 1). It proved to be an easy, low cost and reproducible method proposed to prepare grape extracts that could replace the commercially available ones, used for diagnosis and possibly extend the method to other fruits especially in extracting LTPs.     

Electromagnetic analysis of coupling and guiding phenomena in elliptical cross-section parallel waveguides with rotated symmetry planes

Rigorous electromagnetic analysis methods, based on the Green's function method along with the method of moments, are utilized to analyze coupling, guiding, and polarization phenomena in elliptic cross-section parallel waveguides. The analysis is carried out for the general case of closely spaced elliptic fibers of arbitrary orientation of the ellipses' axes. Numerical results are presented for the cases of 0 degrees and 45 degrees angles between axes, as well as for the single elliptical fiber and closely spaced circular dielectric waveguides. The possibility of using this type of coupling structure in quantum signal processing applications is examined.     

f-Value: measuring an article’s scientific impact

The f-value is a new indicator that measures the importance of a research article by taking into account all citations received, directly and indirectly, up to depth n. The f-value considers all information present in a Citation Graph in order to produce a ranking of the articles. Apart from the mathematical equation that calculates the f-value, we also present the corresponding algorithm with its implementation, plus an experimental comparison of f-value with two known indicators of an article’s scientific importance, namely, the number of citations and the Page Rank for citation analysis. Finally, we discuss the similarities and differences among the indicators.     

Construction of invariant polytopic sets with specified complexity

The problem of construction of controlled invariant polytopic sets with specified complexity, for linear systems subject to linear state and control constraints, is investigated. First, geometric conditions for the enlargement of a polytopic set by adding a new vertex, in order to produce a polytopic set of specified complexity, are established. Next, conditions for such an enlargement of controlled invariant sets to preserve the controlled invariance property are presented. The established theoretical results are used to develop methods for the construction of admissible controlled invariant sets with specified complexity. Two numerical examples show how these results can be used for the computation of monotonic sequences of admissible controlled invariant sets of specified complexity.