A Representation for Conceptual Design of Buildings

The building representation for storing design solutions adopted in SEED-Config consists of two levels of abstraction models defined on top of the object-oriented data model. The first level is an information model, called the building entity and technology model, which stores design data as they are generated during conceptual design, supports case-based reasoning, and shares data among all design participants. This model represents each building entity as a generic container that encompasses its properties, taxonomy, geometry, composition, relationships, and design knowledge applied in generating it. The second level is a conceptual model that defines the types of objects, relationships, and data needed to fully represent the information in a given design domain. The conceptual model specifies the semantics of the design information for the domain using the syntax defined in the information model. The proposed representation also includes a faceted classification scheme to define the controlled vocabulary from which indexes are obtained. The representation has the following advantages: It integrates multiple views, supports design evolution, supports design exploration, and is extensible.     

Threshold‐voltage drift of amorphous‐silicon TFTs in integrated drivers for active‐matrix LCDs

Abstract— The threshold‐voltage drift of a‐Si TFTs for AMLCD integrated drivers was studied. Analysis of the drift shows two different kinetics. Both charges trapped in the insulator and defect generation in the a‐Si layer occur simultaneously. However, after a period of time charge trapping in the insulator becomes predominant.     

Revisiting gonadotrophin-releasing hormone agonist protocols and management of poor ovarian responses to gonadotrophins

Within the past decade, gonadotrophin-releasing hormone (GnRH) agonists have contributed greatly to the success of cycles programmed for in-vitro fertilization and embryo transfer. However, apart from a preventive effect on the luteinizing hormone (LH) surge, most of the beneficial effects of these molecules are still only partly known. A precise analysis of regimens using GnRH agonists for ovarian stimulation shows that many parameters may interfere with the outcome of long-term and short-term protocols. The great variability between these protocols hampers our comprehension of the mechanisms involved in the overall clinical improvement seen with this therapy. The hypophyseal desensitization induced by GnRH agonists is greatly dependent on the dose and duration of their administration, but the residual gonadotrophin secretion is imperfectly estimated by hormonal measurements using radioimmunometric assays. Moreover, the specific role of GnRH agonist-induced ovarian quiescence on subsequent ovarian responsiveness to gonadotrophins and on endometrial receptivity deserves further investigation. Finally, a direct ovarian action of GnRH agonists on steroidogenesis, folliculogenesis and embryo quality is still controversial in humans. These putative deleterious effects of GnRH agonists have led some authors to recommend a reduction of both dose and duration of GnRH agonist administration for women identified by a poor response to gonadotrophins. Using this approach, a few reports have recently shown some clinical advantages for ovarian responsiveness but no convincing evidence for any improvement in pregnancy rate. It thus appears that the overall impact of GnRH agonists on reproductive function is still partly misunderstood.     

Screening of representative cider yeasts and bacteria for volatile phenol-production ability

Representative cider microorganisms (47 yeast strains and 16 bacterial strains) were studied for their ability to produce volatile phenols in a synthetic medium simulating cider conditions and supplemented with the necessary precursors. The various strains were tested for cinnamoyl esterase activity and only Lactobacillus collinoides were able to hydrolyse chlorogenic acid. Phenolic acid decarboxylase (PAD) activities were observed for 6 yeasts and 4 bacterial species allowing them to produce vinylphenols from hydroxycinnamic acids. On the other hand, 4 bacterial species exhibited phenolic acid reductase (PAR) activities leading to the formation of hydroxyphenylpropionic acids. Brettanomyces/Dekkera anomala and L. collinoides were able to produce 4-ethylcatechol (4-EC) and 4-ethylphenol (4-EP) from caffeic and p-coumaric acid, respectively, indicating that both species exhibit PAD and vinylphenol reductase (VPR) activities. In the experimental conditions used, the production of ethylphenols by L. collinoides was faster than the one observed for D. anomala.     

GaInNAs-based Hellish-vertical cavity semiconductor optical amplifier for 1.3 μm operation

Hot electron light emission and lasing in semiconductor heterostructure (Hellish) devices are surface emitters the operation of which is based on the longitudinal injection of electrons and holes in the active region. These devices can be designed to be used as vertical cavity surface emitting laser or, as in this study, as a vertical cavity semiconductor optical amplifier (VCSOA). This study investigates the prospects for a Hellish VCSOA based on GaInNAs/GaAs material for operation in the 1.3-μm wavelength range. Hellish VCSOAs have increased functionality, and use undoped distributed Bragg reflectors; and this coupled with direct injection into the active region is expected to yield improvements in the gain and bandwidth. The design of the Hellish VCSOA is based on the transfer matrix method and the optical field distribution within the structure, where the determination of the position of quantum wells is crucial. A full assessment of Hellish VCSOAs has been performed in a device with eleven layers of Ga_0.35In_0.65N_0.02As_0.08/GaAs quantum wells (QWs) in the active region. It was characterised through I-V, L-V and by spectral photoluminescence, electroluminescence and electro-photoluminescence as a function of temperature and applied bias. Cavity resonance and gain peak curves have been calculated at different temperatures. Good agreement between experimental and theoretical results has been obtained.     

How different messaging semantics can affect SCA applications performances: a benchmark comparison

Software Communications Architecture (SCA) compliant radios typically contain a large number of software components. Some software components provide access to hardware devices while others perform signal processing. By interacting with each other, the software components implement a radio communications standard. To interact, the software components use a middleware called Common Object Request Broker Architecture (CORBA). Using CORBA, each interaction is carried out as an exchange of messages between two components. CORBA supports two main types of messaging: one-way and two-way. This article explores the differences between the two types of messaging and provides performance metrics. The article also describes design approaches that can be used to avoid common pitfalls associated with the use of both types of messaging.     

Collective response to perturbations in a data-driven fish school model

Fish schools are able to display a rich variety of collective states and behavioural responses when they are confronted by threats. However, a school''s response to perturbations may be different depending on the nature of its collective state. Here we use a previously developed data-driven fish school model to investigate how the school responds to perturbations depending on its different collective states, we measure its susceptibility to such perturbations, and exploit its relation with the intrinsic fluctuations in the school. In particular, we study how a single or a small number of perturbing individuals whose attraction and alignment parameters are different from those of the main population affect the long-term behaviour of a school. We find that the responsiveness of the school to the perturbations is maximum near the transition region between milling and schooling states where the school exhibits multistability and regularly shifts between these two states. It is also in this region that the susceptibility, and hence the fluctuations, of the polarization order parameter is maximal. We also find that a significant school''s response to a perturbation only happens below a certain threshold of the noise to social interactions ratio.     

Antioxidant composition and activity of barley (Hordeum vulgare) and malt extracts and of isolated phenolic compounds

Phenolics have been identified and quantified in nine varieties of barley and their corresponding malts as flavan-3-ols, flavonols, phenolic acids and apolar esters. Flavan-3-ols are monomers, (+)-catechin and (−)-epicatechin, and polymers constituted mainly by units of (+)-catechin and (+)-gallocatechin. The most abundant compounds were the dimers procyanidin B3 and prodelphinidin B3. The main trimeric procyanidin was procyanidin C2. After malting, the phenolic content decreased for all varieties. Catechin monomers were the most affected. Beside polyphenols, barley and malt extracts contained other antioxidants: carotenoids (lutein and zeaxanthin) and tocopherols (α, δ and γ). The antioxidant activity was measured using three methods: capacity to react with DPPH^. (ARP), inhibition of lipoxygenase activity (LoxI) and inhibition of cooxidation of β-carotene in a linoleate model system (AOP). The inhibition of cooxidation of β-carotene in a linoleate model system did not allow varieties to be discriminated. They all have high antioxidative properties. Using this assay, tocopherols were the best antioxidants. The ARP (antiradical power) was correlated positively with the amount of total flavan-3-ols (r = 0.89) and increased with the degree of polymerisation. The LoxI assay allowed discrimination of the nine varieties of barley and their corresponding malts but was not correlated with any compound, although flavan-3-ols were good inhibitors of lipoxygenase activity. © 1999 Society of Chemical Industry