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21.
The purpose of this paper is to provide guidelines for building a word alignment evaluation scheme. The notion of word alignment quality depends on the application: here we review standard scoring metrics for full text alignment and give explanations on how to use them better. We discuss strategies to build a reference corpus, and show that the ratio between ambiguous and unambiguous links in the reference has a great impact on scores measured with these metrics. In particular, automatically computed alignments with higher precision or higher recall can be favoured depending on the value of this ratio. Finally, we suggest a strategy to build a reference corpus particularly adapted to applications where recall plays a significant role, like in machine translation. The manually aligned corpus we built for the Spanish-English European Parliament corpus is also described. This corpus is freely available.  相似文献   
22.
Nuclear fusion D+D processes are studied by nanosecond pulsed laser interaction with ultra-dense deuterium. This material has a density of 1029 cm?3 as shown in several previous publications. Laser power is <2 W (0.2 J pulses) and laser intensity is <1014 W cm?2 in the 5–10 μm wide beam waist. Particle detection by time-of-flight energy analysis with plastic scintillators is used. Metal foils in the particle flux to the detector remove slow ions, and make it possible to convert and count particles with energy well above 1 MeV. The variation of the signal of MeV particles from D+D fusion is measured as a function of laser power. At relatively weak laser-emitter interaction, the particle signal from the laser focus varies as the square of the laser power. This indicates collisions in the ultra-dense deuterium of two fast deuterons released by Coulomb explosions. During experiments with stronger laser-emitter interaction, the signal varies approximately as the sixth power of the laser power, indicating a plasma process. At least 2 × 106 particles are created by each laser pulse at the maximum intensity used. Our results indicate break-even in fusion at a laser pulse energy of 1 J with the same focusing, in approximate agreement with theoretical results for ignition conditions in ultra-dense deuterium. Radiation loss at high temperature will however require higher laser energy at break-even.  相似文献   
23.
Recently, a number of empirical studies have compared the performance of PCA and ICA as feature extraction methods in appearance-based object recognition systems, with mixed and seemingly contradictory results. In this paper, we briefly describe the connection between the two methods and argue that whitened PCA may yield identical results to ICA in some cases. Furthermore, we describe the specific situations in which ICA might significantly improve on PCA  相似文献   
24.
The international planning competition (IPC) is an important driver for planning research. The general goals of the IPC include pushing the state of the art in planning technology by posing new scientific challenges, encouraging direct comparison of planning systems and techniques, developing and improving a common planning domain definition language, and designing new planning domains and problems for the research community. This paper focuses on the deterministic part of the fifth international planning competition (IPC5), presenting the language and benchmark domains that we developed for the competition, as well as a detailed experimental evaluation of the deterministic planners that entered IPC5, which helps to understand the state of the art in the field.We present an extension of pddl, called pddl3, allowing the user to express strong and soft constraints about the structure of the desired plans, as well as strong and soft problem goals. We discuss the expressive power of the new language focusing on the restricted version that was used in IPC5, for which we give some basic results about its compilability into pddl2. Moreover, we study the relative performance of the IPC5 planners in terms of solved problems, CPU time, and plan quality; we analyse their behaviour with respect to the winners of the previous competition; and we evaluate them in terms of their capability of dealing with soft goals and constraints, and of finding good quality plans in general. Overall, the results indicate significant progress in the field, but they also reveal that some important issues remain open and require further research, such as dealing with strong constraints and computing high quality plans in metric-time domains and domains involving soft goals or constraints.  相似文献   
25.
This part of the volume contains the papers accepted for presentation at the workshop on Unification in Non-Classical Logics (UNCL), co-located with ICALP 2002, which took place on July 12, 2002 in M 'alaga, Spain.The workshop was concerned with one of the most promising areas of research on non-classical logics and its applications. Unification in non-classical logics, with various approaches to handling generalised terms, has drawn more and more attention in recent years. So far, most popular lines of research include fuzzy unification of (conventional) databases and the use of fuzzy concepts in information retrieval.This workshop was conceived as a forum for the exchange of ideas relevant for the concept of unification in non-classical logics, including, but not limited to, the topics of:
• Unification in multiple-valued and fuzzy logic programming.
• Unification based on similarities and fuzzy equivalence relations.
• Categorical unification.
• Practical use of non-classical unification, e.g. in expert systems and information retrieval.
The program committee selected six papers after a reviewing process in which each submitted paper received at least two reviews. Considerable effort was devoted for the evaluation of the submissions and to providing the authors with helpful feedback. The criteria for selection were originality, quality, and relevance to the topic of the workshop.Alsinet et al reviewed and compared two models which extend first order possibilistic logic in order to enable fuzzy unification. The extension considers mainly fuzzy constants, and in form of restrictions on existential quantifiers.Banerjee and Bujosa presented a non-classical interpretion of classical unification in terms of geometrical constructions over a suitable R-module M. The main result is that unification of two terms can be seen as the intersection of their corresponding affine varieties on M. This paves the way of using methods from computer algebra in the field of unification.In Eklund et al, substitutions and unifiers appear as constructs in Kleisli categories related to particular composed powerset term monads. It is shown that an often used similarity-based approach to fuzzy unification is compatible with the categorical approach, and can be adequately extended.Kutsia presented a unification procedure for a theory with individual and sequence variables, free fixed and flexible arity function symbols and patterns. These theories have been used in different contexts such as databases, rewriting, programming languages, or theorem proving.Medina et al introduced a formal model for similarity-based fuzzy unification in multi-adjoint logic programs. On this computational model, a similarity-based unification approach which provides a semantic framework for logic programming with different notions of similarity was constructed.Virtanen introduced unification in similarity-based logic programming. One of the crucial points is the definition of similarity degrees between sets, giving rise to [lambda]-interpretations. The selection of so called most significant terms again is one of the cornerstones of the paper.We would like to thank all those who submitted papers for consideration, the authors of accepted papers for their interesting discussions during the workshop, the additional referees for their careful work, and Inma Fortes from the local organising committee for her assistance.  相似文献   
26.
27.
This study describes the utilization of acoustic cues in communication of emotions in music performance. Three professional guitarists were asked to perform 3 short melodies to communicate anger, sadness, happiness, and fear to listeners. The resulting performances were analyzed with respect to 5 acoustic cues and judged by 30 listeners on adjective scales. Multiple regression analysis was applied to the relationships between (a) the performer's intention and the cues and (b) the listeners' judgments and the cues. The analyses of performers and listeners were related using C. J. Hursch, K. R. Hammond, and J. L. Hursch's (1964) lens model equation. The results indicated that (a) performers were successful at communicating emotions to listeners, (b) performers' cue utilization was well matched to listeners' cue utilization, and (c) cue utilization was more consistent across different melodies than across different performers. Because of the redundancy of the cues, 2 performers could communicate equally well despite differences in cue utilization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
28.
A mathematical model for simulating a passive aluminium (Al) surface with a pit in which active electrochemical metal dissolution occurs has been developed. The model includes hydrolysis products of Al and the species obtained as a result of homogeneous reactions between chloride and Al3+ ions and Al hydrolysis products. The model does not assume the equilibrium state in solution: all terms in homogeneous reactions are treated explicitly using kinetic constants taken from the literature. The validity of assuming reaction equilibrium has been addressed. Solution potential values and species concentrations are predicted for different dissolution current densities. The acidity in the pit is explained by the hydrolysis of Al3+; an analytical expression for the pH values at the pit bottom for a given dissolution current density is presented.The model is applied to a real capillary geometry used in electrochemical microcell experiments. It was found that for rcap/rpit < 100, where rcap and rpit are the capillary end and pit radii, respectively, the insulating capillary wall affects the species concentrations and the solution potential. Moreover, for rcap/rpit < 20, the shape of the capillary, which might not be cylindrical, should be taken into account.  相似文献   
29.
A method for identifying and quantifying bitumen particles, generated from the wear of roadway asphalts, in aerosol and soil samples has been developed. Bitumen is found to be the only contributor to airborne particles containing organic molecules with molecular weights larger than 2000 g pr. mol. These are separated and identified using High Performance Gel Permeation Chromatography (HP-GPC) with fluorescence detection. As an additional detection method Infra Red spectrometry (IR) is employed for selected samples, The methods have been used on aerosol, soil and other samples.  相似文献   
30.
Engineered barriers for high-level nuclear waste (HLW) consist of excavated repositories in sub-surface rock formations where canisters holding the radionuclide are stored. Clay minerals, particularly the swelling 2:1 types, are used as backfill material, both in the canisters and in the bore hole, in order to prevent radionuclide transport to surrounding groundwater. One of the most important risks that can occur is the corrosion of the canister, which could be coupled with reduction of iron (Fe) in the clay structure. Such changes could greatly decrease the long-term stability of the clay and, consequently, of the barriers themselves. In order to test the potential effects of such redox interactions, an Fe-bearing clay mineral from a commercial source located in the Kutch region, India, was selected for study. This particular mineral is one of the candidate clay minerals to serve as such a barrier material, and is the one with the largest structural Fe content. Results from it should, therefore, provide maximum insight into the potential effects of redox interactions between the barrier and its surroundings. The unaltered clay was characterized by X-ray powder diffractometry (XRD), thermal gravimetric analysis (TGA/DTGA), Fourier-transform infrared (FTIR) spectroscopy, and variable-temperature Mössbauer spectroscopy. The chemically reduced and reoxidized forms of the clay were characterized by variable-temperature Mössbauer spectroscopy and chemical analysis. In the unaltered state the clay is comprised of smectite, maghemite, superparamagnetic goethite, and hematite, with a possible trace of kaolinite. In the reduced state the Fe (oxyhydr)oxides were dissolved. Upon reoxidation no six-line pattern was observed, indicating that the Fe remained only in the structure of the silicates. The final structure of the reduced–reoxidized clay contained more defects than the original clay, as revealed by greater quadrupole splitting values for structural Fe(III) in the clay. These findings indicate that upon exposure to natural redox cycles the Kutch clay could undergo permanent changes in its mineralogical composition and clay mineral structure, but further study is required to ascertain the effects that such changes would have on its long-term stability as a barrier material.  相似文献   
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