Cooperative Query Answering with Generalized Quantifiers

The use of Generalized Quantifiers in query languages was introduced independently in (Hsu and Parker, 1995; Gyssens et al., 1995). In both cases it is argued that GQs make query languages more able to handle complex queries in a declarative way and provide a syntax more similar to natural language. In this paper we argue that query languages with Generalized Quantifiers can be used to produce cooperative question answering (Gaasterland et al., 1992). We introduce the Query Language with Generalized Quantifiers QLGQ and review related work in cooperative query answering, focusing on research that has direct connections with the results of this paper. Then we show how to use Generalized Quantifiers in dealing with false presuppositions, constructing justifications, and query relaxation. For each technique, we give examples that suggest that Generalized Quantifiers are better suited to the application of the technique than traditional approaches.     

Cuticular Hydrocarbons of Polistes dominulus as a Biogeographic Tool: A Study of Populations from the Tuscan Archipelago and Surrounding Areas

In social insects, the types and proportions of epicuticular lipids may exhibit significant diversity as a result of factors such as age, sex, caste, rank, nest, and relatedness. It is known that these variations can be used by social insects to acquire information regarding conspecific individuals. Recent findings have shown that different populations of Polistes dominulus (Christ.) have distinctly different chemical cuticular profiles, and that wasps are able to recognize individuals of their own population. In this study, we showed that cuticular hydrocarbon patterns of Polistes dominulus are consistent with similarities among northern Tyrrhenian islands, as reported in previous biogeographic studies. Indeed, our findings indicate that cuticular hydrocarbon mixtures of P. dominulus from Capraia and Corsica are grouped together by cluster analysis, while those from Elba and Giglio cluster with cuticular profiles of the mainland wasps (Venturina).     

Modelling of Emission and Re-emission of Volatile Organic Compounds from Building Materials with Indoor Air Applications

Polymer materials and their additives are today ever present in our daily surroundings. These materials have been found to emit a number of different volatile organic compounds (VOCs) into the ambient air, thus affecting the quality of the indoor air VOCs with detectable concentrations are exchanged between the different materials and indoor air. Materials present in the system act as sorbents as well as sources of emission, depending on the concentration of the VOCs in the air at a specific time. This work demonstrates a method of studying the phenomena of absorption/re-emission. A hypothetical room that resembles a furnished office has been studied. A PVC flooring material was used as a primary emission source in a system where materials such as wood, paint, cloth, chipboard, and cellulose were present. Mass transfer in the solid materials was assumed to be by diffusion. The results show that the mechanism of absorption/re-emission of volatiles may extend the time of residence in an indoor system considerably. A person working in this environment could risk longer exposure to toxic volatiles than if there were no absorption/re-emission effects.     

Dynamic surface temperature measurements in SiC epitaxial power diodes performed under single-pulse self-heating conditions

Semiconductor devices development, design and optimization require the use of computer simulation tools able to predict the entire device safe operating area (SOA), something that it is not always possible due to limitations in some of the physical models in predicting certain properties of device operation under extreme conditions (i.e. high carrier injection levels and high temperature). In order to improve our understanding of device operation under these extreme conditions experimental data of the dynamic IV characteristics and temperature time evolution and space distribution are required. The experimental data obtained are then used in the development of improved physical models and simulation tools.

In this work, dynamic surface temperature measurements as a function of current pulse peak density and length were performed on SiC-PiN epitaxial power diodes. The measurements were carried out using an infrared (IR) microscope developed in our lab capable of measuring space and time surface temperature distributions in semiconductor devices operating under self-heating conditions [Solid State Electron 2001;45(12):2057]. The minimum detected spot size is 15 μm, while the signal raising time is detector limited to about 1 μs. The lowest detectable temperature increment is at least 10 °C over room temperature.

Using this instrument, dynamic thermal phenomena in 4.5 kV SiC-PiN epitaxial power diodes [Mater Sci Forum 2001;353–356:727] subjected to 1 ms long 100–6000 A/cm² and 0.1–5 ms long 3000 A/cm² current pulses have been studied. The possibility of obtaining dynamic surface temperature information from SiC electronic devices operating under self-heating conditions with time constants in the order of ms is demonstrated.     

DYNAMIC POSITIONING CONTROL OF SHIPS VIA RELAY OBSERVER DESIGN

A dynamically positioned ship maintains its position (fixed location or predetermined track) exclusively by means of active thrusters. In this paper, a control scheme for dynamic positioning control of ships using a relay observer design is presented. Our analysis relies on nonsmooth strict Lyapunov functions to demonstrate global asymptotic stability of the closed‐loop system equilibrium. Using simulation results we illustrate the good performance of the proposed scheme under noisy ship position measurements.     

Anisotropic Scaling in YBa2Cu3O7 Crystals with Columnar Defects

We explore the interplay between the mass anisotropy and the uniaxial pinning of tilted columnar defects (CD) in a YBa₂Cu₃O₇ single crystal. At high temperatures T and fields H a sharp peak in the irreversible magnetization M _i at the direction of the tracks signals the presence of the CD. At low T such a peak is not observed, and the influence of the CD appears only as a perturbation to the angular dependence due to the anisotropy. We show that at low T and high H the uniaxial effects due to CD can be recovered by performing an anisotropic rescaling. As expected, this scaling fails at low H.     

Reversible and irreversible degradation in fuel cells during Open Circuit Voltage durability testing

In this study reversible and irreversible voltage loss in a polymer electrolyte membrane fuel cell undergoing an open circuit voltage (OCV) durability test was studied. OCV durability testing is thought to promote chemical degradation of the electrolyte membrane material via radical attack and degradation of the catalyst layer. The results for degradation under constant relative humidity showed that voltage degradation rates measured in the first 20–50 h after polarization curve measurement consisted of a reversible, or transient, and irreversible component. A steady voltage decay rate became evident after 50 h of operation. Comparison to the voltage decay rates obtained from polarization curves showed that the steady voltage decay rate was representative of irreversible voltage loss due to irreversible changes in materials as shown by crossover and active surface area measurements. This study highlights the necessity of understanding the difference between reversible and irreversible voltage decay rates since the reversible decay rates were found to be much higher than irreversible decay rates.     

Biomass-fired cogeneration systems with CO2 capture and storage

In this study, we estimate and analyze the CO₂ mitigation costs of large-scale biomass-fired cogeneration technologies with CO₂ capture and storage. The CO₂ mitigation cost indicates the minimum economic incentive required (e.g. in the form of a carbon tax) to make the cost of a less carbon intensive system equal to the cost of a reference system. If carbon (as CO₂) is captured from biomass-fired energy systems, the systems could in principle be negative CO₂ emitting energy systems. CO₂ capture and storage from energy systems however, leads to reduced energy efficiency, higher investment costs, and increased costs of end products compared with energy systems in which CO₂ is vented. Here, we have analyzed biomass-fired cogeneration plants based on steam turbine technology (CHP-BST) and integrated gasification combined cycle technology (CHP-BIGCC). Three different scales were considered to analyze the scale effects. Logging residues was assumed as biomass feedstock. Two methods were used to estimate and compare the CO₂ mitigation cost. In the first method, the cogenerated power was credited based on avoided power production in stand-alone plants and in the second method the same reference output was produced from all systems. Biomass-fired CHP-BIGCC with CO₂ capture and storage was found very energy and emission efficient and cost competitive compared with other conversion systems.