AZores Observation NETwork – AZONET

Workshop on Integrated Observations for Assessing Hemispheric Transport. Geneva, Switzerland, 24-26 January 2007

From Lexical to Semantic Features in Paraphrase Identification

The task of paraphrase identification has been applied to diverse scenarios in Natural Language Processing, such as Machine Translation, summarization, or plagiarism detection. In this paper we present a comparative study on the performance of lexical, syntactic and semantic features in the task of paraphrase identification in the Microsoft Research Paraphrase Corpus. In our experiments, semantic features do not represent a gain in results, and syntactic features lead to the best results, but only if combined with lexical features

Comparison of Elemental Carbon (EC) and Black Carbon (BC) measurements derived by Thermo-Optical and filter-based light transmission techniques at North Atlantic.

7th International Aerosol Conference. St. Paul, Minnesota, 10-15 September 2006.Terceira Island (38.691º; 27.354º; 50 m altitude) in the Azores Archipelago, developed to provide a base for remote marine boundary layer measurements at a location near the PICO-NARE (Honrath & Fialho, 2002) (Figure 1). In order to determine a long term carbonaceous component of atmospheric aerosols in North Atlantic, measurements of aerosol BC and EC were begun in 2002. EC and BC define similar fraction of the carbonaceous component of atmospheric aerosols and are supposed to be comparable, but have a delicate different thermal, optical and chemical behaviour in most cases (Lavanchy et al., 1999)

Optical Measurement and Aerosol Filter Loading for Climate Studies.

Fall Physics Colloquium. Houghton, Michigan, September 8th, 2011.Aerosols (small particles suspended in the atmosphere) contribute to climate change by altering Earth's radiative balance. Aerosol optical properties determine their effects on climate, causing either positive forcing (increasing temperature) or negative forcing (decreasing temperature). For these reasons recent climate research has been focused on understating the aerosol properties and roles. Aerosols are not "pure" uniform species, they are complex mixtures of several types with different scattering and absorption specific coefficients, that can be associated to specific source types. Therefore, the best approach to understand the aerosol effect on climate would be to characterize each type of aerosols and provide parametrizations for climate models. The increased importance to comprehend the aerosol role in the atmosphere is responsible for the continuous development of novel optical techniques capable of responding to their presence and providing information on their properties. These techniques can be split in two types of groups: the ones that measure the radiation perturbation due to the aerosol presence in a column of air; and the others that measure the radiation perturbation that results from the aerosol accumulated on a filter surface. The present talk will consider the last group, in particular the use of the Aethalometer, and will show an ongoing research work for empirically compensating the attenuation coefficient, σATN(λ, t), due to the cumulative loading effect

In memory of Richard Honrath. Pico Mountain, Why should we continuum?

Work Meeting. Houghton, Michigan, 2011

Prediction of the vapor pressure of environmentally acceptable halocarbons.

Copyright © 2000 Plenum Publishing Corporation.The vapor pressure and its dependence on temperature of halocarbons for 0.002< p R<1 have been analyzed in terms of universal behavior. Results for CFC-114, HCFC-123, HCFC-141b, HCFC-142b, HCFC-143a, HFC-23, HFC-32, HFC-134, HFC-125, HFC-134a, and HFC-152a for reduced temperatures between 0.55 and 1.0 show that the reduced vapor pressure can be expressed as a function of 1−T R by a Padé approximant. Deviations of the correlated data from the universal function do not amount to more than ±0.06 MPa, with an average deviation of 0.025 MPa. Predictions of the saturation vapor pressures of HCFC-124, HCFC-225ca, and HCFC-225cb, which are the systems used to test the capability of this scheme, agree within 0.025 MPa, that is, within the accuracy of the corresponding states correlation. However, for HFC-236ea, the deviations are as large as -0.07 MPa. The present scheme can be used to calculate the Pitzer acentric factor, and an average value of ω=0.269±0.015 is obtained for all the fluids

Applications of the hard sphere DeSantis equation of state to the estimation of the density of compressed alternative refrigerants.

19th International Congress of Refrigeration. Proceedings The Hague, the Netherlands, august 20-25, 1995.The density of liquid refrigerants is very important for the design of compression cycles in the refrigeration and air conditioning industries. The increasing concern with the environmental protection leads the governments to legislate in order to banish in the short term the use of the CFC's and in the long run the HCFC's. Considering those decisions, the industries need to find new replacements for those compounds, and suitable substitutes seam to be HFC's, fluorinated ethers, their mixtures and mixtures with small quantities of HCFC's. The only problem in using those alternative refrigerants is the lack of knowledge about their properties. Among them, the density is one of the most important. It is the propose of this paper to show the use of a model that allows the user to estimate the liquid density for the refrigerants. The uncertainty of this model is of ± 2.0 % for reduced values of temperature less then 0.95 and reduced values of density less then 1.0. This model needs the information for the critical parameters and the pressure of the saturated liquid-vapour line. The Hard-Sphere DeSantis equation of state Ref. /1/ is use to give physical support to the model. The corrections to the attractive and repulsive part, a and b, have been calculated from a few experimental pure refrigerants Ref. /1/ (HCFC 152a, HCFC 22, HCFC 142b, HCFC 123, HCFC 114)

A Stochastic Model for Managing Tasks of R&D Projects

In this paper, we propose a model for managing tasks of R&D projects. We assume that di®erent amounts of resources may be allocated to a task, leading to different costs, and di®erent average execution speeds. The advancement of the task will be stochastic, and the manager may change the allocated amount of resources according to the way the task is progressing. The revenues will depend on the time to the completion of the task, and their expected value will follow a stochastic process. We consider that a strategy for completing the task will consist on a set of rules that de¯ne the level of resources to be chosen at each moment, according to the values of several state variables. We discuss the evaluation for completing the task, and we brie°y address the problem of finding the optimal strateg

A tool to manage tasks of R&D projects

We propose a tool for managing tasks of Research and Development (R&D) projects. We define an R&D project as a network of tasks and we assume that different amounts of resources may be allocated to a task, leading to different costs and different average execution times. The advancement of a task is stochastic, and the management may reallocate resources while the task is being performed,according to its progress. The operational cash flows depend on the task completion time, and their expected values follow a stochastic process. We consider that a strategy for completing a task is a set of rules that define the level of resources to be allocated to the task at each moment. We discuss the evaluation of strategies for completing a task, and we address the problem of finding the optimal strateg