934 research outputs found
Pulmonary vein isolation in the treatment of atrial fibrillation
No full textSaurabh Kumar, Gregory F Michaud Cardiac Arrhythmia Service, Cardiovascular Division, Brigham and Women's Hospital, Boston, MA, USA Abstract: Atrial fibrillation (AF) is the commonest arrhythmia in humans and is associated with marked reduction in quality of life and an elevated thromboembolic risk. Paroxysmal, persistent, and permanent forms of AF have been recognized. Whilst antiarrhythmic drugs are considered as first-line therapy, the role of catheter ablation is increasing due to its superior efficacy in terms of quality of life and reduction in AF burden. The central paradigm for catheter ablation of AF is that triggers for AF are located near and within the pulmonary veins (PVs), and electrical isolation of the PVs from the left atrium forms the cornerstone of most catheter ablation strategies. Whilst paroxysmal form is generally trigger dependent, persistent and permanent forms are associated with variable interaction between triggers and "substrate" comprised of atrial and PV electrical and structural remodeling. Nevertheless, isolation of the PVs still forms a critical component of catheter ablation strategies, regardless of AF type. Procedural efficacy, however, is limited by PV conduction recovery. This is likely due to deficiencies in ablation tools or limitations of intraprocedural assessment of lesion efficacy. Careful attention to surrogates of tissue heating, such as impedance decrease and electrogram morphology changes, along with advances in catheter technology like contact force catheters may improve rates of durable PV isolation and single-procedural success. This review discusses the mechanism of paroxysmal AF with particular focus on the role of the PVs in AF initiation and PV isolation in the management of AF. Keywords: contact force, lesion transmurality, radiofrequency catheter ablation, paroxysmal atrial fibrillation, electrophysiology, A
Language Engineering in Grammatical Framework (GF)
No full textThis thesis describes a number of practical experiments rather than theoreticalinvestigations in the area of natural language processing. The basis forthe work presented is Grammatical Framework (GF). It is a very complexsystem, which comprises among other things a grammar formalism based ontype theory and its implementation written in Haskell. GF is intended forhigh-quality machine translation (of INTERLINGUA type) in the restrictedlanguage domains.The primary concern of this thesis is however limited to the usage of GFas a piece of software. The main results are: Implementing a syntax editor, which provides a graphical user interface(GUI) for the command-line GF core. Writing a part of code for automatic generation of gramletspure Javaprograms with limited (compared to GF) functionality that can be runon PDA (Portable Device Assistants) and as applets in a browser. Writing the Russian resource grammar that takes care of the most basicmorphological and syntactic rules and serves as a standard libraryfor building application grammars (describing restricted language domains)in Russian.These results contribute to language engineering in GF on two differentlevels: Author level (end-user) constructing sentences in natural languages. Grammarian level building a grammar description, which is laterused on the author level.The last part of the thesis deals with a non-linguistic domain. In thatexperiment we try to apply functional parsing technique to the well-knownproblem of protein secondary structure prediction (bioinformatics)
Language Engineering in Grammatical Framework (GF)
No full textThis thesis describes a number of practical experiments rather than theoreticalinvestigations in the area of natural language processing. The basis forthe work presented is Grammatical Framework (GF). It is a very complexsystem, which comprises among other things a grammar formalism based ontype theory and its implementation written in Haskell. GF is intended forhigh-quality machine translation (of INTERLINGUA type) in the restrictedlanguage domains.The primary concern of this thesis is however limited to the usage of GFas a piece of software. The main results are: Implementing a syntax editor, which provides a graphical user interface(GUI) for the command-line GF core. Writing a part of code for automatic generation of gramletspure Javaprograms with limited (compared to GF) functionality that can be runon PDA (Portable Device Assistants) and as applets in a browser. Writing the Russian resource grammar that takes care of the most basicmorphological and syntactic rules and serves as a standard libraryfor building application grammars (describing restricted language domains)in Russian.These results contribute to language engineering in GF on two differentlevels: Author level (end-user) constructing sentences in natural languages. Grammarian level building a grammar description, which is laterused on the author level.The last part of the thesis deals with a non-linguistic domain. In thatexperiment we try to apply functional parsing technique to the well-knownproblem of protein secondary structure prediction (bioinformatics)
Language Engineering in Grammatial Framework (GF)
No full textThe basis for the work presented is Grammatical Framework (GF)a grammar
formalism based on type theory. It is also a powerful language processor
that provides a convenient framework for various multilingual applications.
The primary concern of this thesis is the usage of GF as a piece of software.
The main results are:
Implementing a syntax editor, which provides a graphical user interface
(GUI) for the command-line GF core.
Writing the Russian resource grammar that takes care of the most
basic morphological and syntactic rules and serves as a standard library
for building application grammars (describing sublanguage domains) in
Russian.
These results contribute to language engineering in GF on two different
levels:
Author level (end-user)constructing documents in natural languages.
Grammarian level building a grammar description, which is later
used on the author level. One can also distinguish between application
and resource grammars. An application grammar focuses of a particular
sub-language domain, while resource grammar is a general-purpose
grammar that forms a basis for application grammars
Internship at GoFoton GF Micro Optics Philippines, Inc.
No full textThis paper is a compilation of the internship of the author in the 1st semester of the academic year 2012-2013. It serves as a documentation of the activities that transpired in the internship of the author in GF Micro Optics Philippines, Inc. from May, 1012 until August, 2012.
Included in this paper are the company profile, experiences of the author in the company, and the tasks assigned while taking the training course. Process flow improvement was the main task of the author as his main role under the Industrial Engineering Department of GF Micro Optics Philippines, Inc.
Furthermore, the paper includes problems encountered and lessons learned by the author throughout the training course. These lessons include time management, co-worker management, task management, and enhancement of the authors whole being and skills such as problem solving. All are explained in this manuscript in order to provide self and academic evaluation of the authors training
Linear complexity profile of sequences over the field GF(Q)
No full textSummary form only given. The author extends Reuppel's concept of the linear complexity profile of binary sequences to sequences over an arbitrary finite field and provides formulas for the expected linear complexity and its variance of sequences Sn of length n over GF(q). He shows that the variance approaches 1/q when q approaches ∞. He presents criteria that could be useful when using the linear complexity profile for investigating the randomness of sequences over GF(q). Finally, the author investigates how useful these criteria are by comparing the results with other randomness tests
Linear complexity profile of sequences over the field GF(Q)
No full textSummary form only given. The author extends Reuppel's concept of the linear complexity profile of binary sequences to sequences over an arbitrary finite field and provides formulas for the expected linear complexity and its variance of sequences Sn of length n over GF(q). He shows that the variance approaches 1/q when q approaches ∞. He presents criteria that could be useful when using the linear complexity profile for investigating the randomness of sequences over GF(q). Finally, the author investigates how useful these criteria are by comparing the results with other randomness tests
Toxicity of fruit fly baits to beneficial insects in citrus
No full textTwo fruit fly baits, Nu-Lure®/malathion and GF-120 (Spinosad®) were evaluated in the laboratory for non-target impacts on beneficial insects. Nu-Lure/malathion proved attractive and toxic to adults and larvae of the coccinellid species, Curinus coeruleus Mulsant, Cycloneda sanguinea L. and Harmonia axyridis Pallas, a lacewing species, Chrysoperla rufilabris Burmeister. The coccinellids Olla v-nigrum Mulsant, Scymnus sp. and nymphs of the insidious flower bug, Orius insidiosus (Say) did not succumb to Nu-Lure baits, even in no-choice situations. Nu-Lure was also attractive and lethal to adults of two aphidophagous flies; Leucopis sp. and the syrphid fly Pseudodorus clavatus (F.). Both Nu-Lure and GF-120 caused significant mortality to the parasitoid wasps, Aphytis melinus De Bach and Lysiphlebus testaceipes Cresson, within 24 h of exposure. However, GF-120 caused no significant mortality to any coccinellid in either choice or no-choice situations, despite considerable consumption of baits. Adults of P. clavatus tended to avoid GF-120, although mortality was significant in no-choice tests. Although larvae and adults of the lacewing C. rufilabris consumed GF-120, mortality was delayed; adults died 48 -96 h post-exposure and those exposed as larvae died two weeks later in the pupal stage. The Nu-Lure bait did not appear palatable to any of the insects, but the high concentration of malathion (195,000 ppm) caused rapid mortality to susceptible insects. Nu-Lure bait without malathion also caused significant mortality to flies and lacewings in cage trials. Although GF-120 bait appeared more benign overall, further research efforts are warranted to increase its selectivity for target fly species and reduce its attractiveness to parasitoids and lacewings. I conclude that the Florida "fly free zone" protocol in its current form is not compatible with an IPM approach to commercial citrus production
Thesis for the Degree of Doctor of Philosophy Language Engineering in Grammatical Framework (GF)
No full textThe basis for the work presented is Grammatical Framework (GF) — a grammar formalism based on type theory. It is also a powerful language processor that provides a convenient framework for various multilingual applications. The primary concern of this thesis is the usage of GF as a piece of software. The main results are: • Implementing a syntax editor, which provides a graphical user interface (GUI) for the command-line GF core. • Writing the Russian resource grammar that takes care of the most basic morphological and syntactic rules and serves as a standard library for building application grammars (describing sublanguage domains) in Russian. These results contribute to language engineering in GF on two different levels: • Author level (end-user) — constructing documents in natural languages. • Grammarian level — building a grammar description, which is later used on the author level. One can also distinguish between application and resource grammars. An application grammar focuses of a particular sub-language domain, while resource grammar is a general-purpose grammar that forms a basis for application grammars
A systolic exponentiator for finite fields GF(2m)
No full text[[abstract]]© 1992 Institute of Electrical and Electronics Engineers - The author presents a novel parallel-in-parallel-out bit-level systolic array with unidirectional data flow for computing exponentiation in GF(2m). The array is highly regular and modular, and thus well it is suited to VLSI implementation. In addition, it can provide the maximum throughput in the sense of producing new results at a rate of one per clock cycle. Compared to a previously known systolic (GF2m) exponentiator with the same throughput performance, the proposed system requires much less chip area, has smaller latency, and makes it easier to incorporate fault-tolerant design[[department]]電機工程學
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