452 research outputs found
Electronic and spectral properties of Ge1-xSnx quantum dots: an atomistic study
In this paper, we study theoretically the electron and spectral properties of
Ge1-xSnx systems, including alloys, cubic- and spherical quantum dots. The
single-particle electron and hole states are calculated within the sp3d5s*
tight-binding approach and used in further modeling of the optical properties.
We systematically study the interplay of Sn-driven indirect-direct band-gap
transition and the quantum confinement effect in systems of reduced
dimensionality. We demonstrate the regime of sizes and composition, where the
ground state in Ge1-xSnx quantum dot is optically active. Finally, we calculate
absorbance spectra in experimentally-relevant colloidal quantum dots and
demonstrate a satisfactory agreement with experimental data
Distributed Search in Semantic Web Service Discovery
This thesis presents a framework for semantic Web Service discovery using descriptive (non-functional) service characteristics in a large-scale, multi-domain setting. The framework uses Web Ontology Language for Services (OWL-S) to design a template for describing non-functional service parameters in a way that facilitates service discovery, and presents a layered scheme for organizing ontologies used in service description. This service description scheme serves as a core for desigining the four main functions of a service directory: a template-based user interface, semantic query expansion algorithms, a two-level indexing scheme that combines Bloom filters with a Distributed Hash Table, and a distributed approach for storing service description. The service directory is, in turn, implemented as an extension of the Open Service Discovery Architecture. The search algorithms presented in this thesis are designed to maximize precision and completeness of service discovery, while the distributed design of the directory allows individual administrative domains to retain a high degree of independence and maintain access control to information about their services
Named Entity Recognition -- Is there a glass ceiling?
Recent developments in Named Entity Recognition (NER) have resulted in better
and better models. However, is there a glass ceiling? Do we know which types of
errors are still hard or even impossible to correct? In this paper, we present
a detailed analysis of the types of errors in state-of-the-art machine learning
(ML) methods. Our study reveals the weak and strong points of the Stanford,
CMU, FLAIR, ELMO and BERT models, as well as their shared limitations. We also
introduce new techniques for improving annotation, for training processes and
for checking a model's quality and stability. Presented results are based on
the CoNLL 2003 data set for the English language. A new enriched semantic
annotation of errors for this data set and new diagnostic data sets are
attached in the supplementary materials.Comment: Accepted to CoNLL 201
Adopting ISO 24617-8 for Discourse Relations Annotation in Polish: Challenges and Future Directions
This paper explores a discourse relations annotation project carried out under the CLARIN-PL initiative, leveraging the ISO 24617-8 standard. The goal is to boost research interoperability and foster multilingual research. Our team of three linguist-annotators tackled the annotation of a corpus spanning several genres, including e.g., literature and press articles in the Polish language. This effort was guided by a project expert and external linguists from the CLARIN-PL language technology research infrastructure. Several significant challenges emerged during the process. Ambiguities within the ISO standard’s relation categories, poorly-defined definitions for certain relation categories, and the difficulty of identifying and annotating implicit discourse relations, which lack explicit discourse connectives or signaling devices, were among the key issues. To overcome these problems, we implemented strategies such as regular team meetings, collaborative annotation forms, and preliminary revisions to the annotation scheme. This paper presents the project, the annotation process, and offers initial annotation data on the discourse relations and connectives identified within the corpus. Looking forward, we discuss potential enhancements to the process, including additional revisions to the guidelines and conclude with an overview of the project’s contributions and a discussion of our future development plans
Target, tool, tenure and timing: the four T’s limiting the impact of traditional hunting in Indonesian Papua
Subsistence hunting has sustained human populations in New Guinea for millennia, without seriously affecting the highest levels of biodiversity on Earth. Recent changes to hunting practices, demographic, social and economic context and the introduction of large exotic species has significantly altered the dynamic of hunting and its potential effects in north-west New Guinea. In this paper we examine contemporary hunting practices of six ethnic groups from highland to coastal sites throughout Papua and West Papua provinces of Indonesia. Semi-structured interviews were used to examine hunting practices as well as customary rules and attitudes associated with hunting in the region and how they have changed in living memory. Each group indicated traditional restrictions on at least one of target, tool, timing or tenure, albeit in varied ways. Six different hunting tools were used and each hunter typically combined several tools while hunting. Religious and cultural factors deeply influenced hunting practices among the communities. We discuss the implications of these findings and conclude with recommendations to integrate local, village level governance and customary practices with regional and national law for more effective conservation and management of wildlife in the region while simultaneously respecting cultural heritage and local ecological knowledge
POMIAR CZASU MARTWEGO METODĄ DWÓCH ŹRÓDEŁ – OPTYMIZACJA PODZIAŁU CZASU POMIARU
The article presents the analysis of the dead time measurement using two sources for a non-paralyzable detector. It determined the optimum division of count rate measurement time between both source measurement and a single source one. Results of the work can be used to optimize dead time measurement for systems which count photons or particles.W artykule zaprezentowano analizę pomiaru czasu martwego detektora nieparaliżowalnego metodą dwóch źródeł. Wyznaczono optymalny podział czasu pomiaru częstości zliczeń dla pomiaru jednym i dwoma źródłami. Wyniki pracy mogą być wykorzystane do optymalizacji systemów zliczających fotony lub cząstki
Zrób karierę w bibliotece : materiały z I Forum Młodych Bibliotekarzy, Zielona Góra, 5-6 października 2006
Materiały konferencyjne nr 7
State of the Tropics 2014 report
[Extract] Is life in the Tropics getting better? The landmark State of the Tropics 2014 Report addresses this nominally simple question. It provides the first in-depth, objective assessment of the Tropics as an environmental and geopolitical entity in its own right. Drawing on the knowledge, experience and diverse backgrounds of leading institutions across the Tropics the report assesses the state of the region and examines the implications of the immense changes the region is experiencing.
The assessment demonstrates that nations in the Tropics have made extraordinary progress across a wide range of environmental, social and economic indicators in recent decades. Rapid population and economic growth mean its influence is set to rise dramatically in coming decades. The nature of this influence will depend on how the region addresses its many challenges, and whether it realises its potential and opportunities. The report provides a basis from which to work towards a prosperous, sustainable and equitable future for the Tropics and will be a valuable resource for policy makers, geopolitical analysts, researchers, students and other stakeholders interested in the Tropics
TEORIA WZMOCNIENIA JEDNOFOLIOWEGO DETEKTORA Z GAZOWYM POWIELANIEM ELEKTRONÓW
Gain prediction theory of single foil Gas Electron Multiplier detector was developed. Gas electron multiplier (GEM) detector with single foil was developed. Soft X-ray spectra with an energy of 5.9 keV emitted by the isotope Fe-55 were measured. On this basis, the dependence of gain and energy resolution from the detector voltage was determined. The simple theory of gain dependence on various detector parameters was developed. Preliminary results of the study confirmed the potential usefulness of the GEM detector as a substitute for the multiwire proportional chamber.Opracowano teorię wzmocnienia jednofoliowego detektora z gazowym powielaniem elektronów. Opracowano detektor z gazowym powielaniem elektronów z pojedynczą folią. Zmierzono widmo miękkiego promieniowania X, o energii 5,9 keV, emitowanego przez izotop Fe-55. Na tej podstawie wyznaczono zależność wzmocnienia i energetycznej zdolności rozdzielczej od napięcia zasilającego detektor. Opracowano prosta teorią zależności wzmocnienia od różnych parametrów detektora. Wstępne rezultaty badań potwierdzają potencjalną przydatność detektora GEM jako substytutu wielodrutowej komory proporcjonalnej
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