13 research outputs found
Extreme-Point-based Heuristics for the Three-Dimensional Bin Packing problem
One of the main issues in addressing three-dimensional packing problems is finding an efficient and accurate definition of the points at which to place the items inside the bins, because the performance of exact and heuristic solution methods is actually strongly influenced by the choice of a placement rule. We introduce the extreme point concept and present a new extreme point-based rule for packing items inside a three-dimensional container. The extreme point rule is independent from the particular packing problem addressed and can handle additional constraints, such as fixing the position of the items. The new extreme point rule is also used to derive new constructive heuristics for the three-dimensional bin-packing problem. Extensive computational results show the effectiveness of the new heuristics compared to state-of-the-art results. Moreover, the same heuristics, when applied to the two-dimensional bin-packing problem, outperform those specifically designed for the proble
Basaltic Dyke with Specific Volcanogenic Structures and its geomorphic evolution: Unique Geoheritage of the Faroe Islands (North Atlantic Ocean)
Volcanic landforms resulting from Cenozoic volcanism represent the most peculiar features of global geodiversity and provide eminent narratives for geoeducation. Among them, however, relict volcanic forms and site-specific landforms in remote areas have received less attention. In this paper, we provide the first description of unique volcanogenic features (hereinafter referred to as pseudo-hieroglyphs) developed on a summit rock wall at the Sandfelli ridge near the village of GjĂłgv in the N Eysturoy Island (Faroe Islands). The geomorphic evolution of the ridge and rock wall during the Quaternary is described and detailed petrographic analyses of the volcanogenic features are provided. Based on observed petrographical features, we interpret the pseudo-hieroglyphs to probably represent unique examples of chaotic horizontal columnar jointing. Following the geomorphological and petrographic examination of the study site, we analyse current Faroese legislation aiming at nature conservation and use this case to discuss broader implications of geoheritage conservation and geotourism in distant regions.Vulkanická krajina vzniklá kenozoickĂ˝m vulkanismem pĹ™edstavuje nejpodivnÄ›jšà rysy globálnĂ geodiversity a poskytuje vynikajĂcĂ pĹ™ĂbÄ›hy pro geovzdÄ›lávánĂ. MĂ©nÄ› pozornosti se však dostává reliktnĂm vulkanickĂ˝m formám a lokálnĂm tvarĹŻm reliĂ©fu v odlehlĂ˝ch oblastech. V tomto ÄŤlánku pĹ™inášĂme prvnĂ popis unikátnĂch vulkanogennĂch tvarĹŻ (dále jen "pseudo-hieroglyfy"), kterĂ© se vyvĂjely na skalnĂ stÄ›nÄ› vrcholu na hĹ™betÄ› Sandfelli u vesnice GjĂłgv v severnà části ostrova Eysturoy (FaerskĂ© ostrovy). Je popsán geomorfologickĂ˝ vĂ˝voj hĹ™betu a skalnĂ stÄ›ny bÄ›hem kvartĂ©ru a jsou uvedeny podrobnĂ© petrografickĂ© analĂ˝zy vulkanogennĂch vlastnostĂ. Na základÄ› pozorovanĂ˝ch petrografickĂ˝ch rysĹŻ interpretujeme pseudo-hieroglyfy, kterĂ© pravdÄ›podobnÄ› pĹ™edstavujĂ jedineÄŤnĂ© pĹ™Ăklady chaotickĂ© horizontálnĂ sloupcovitĂ© odluÄŤnosti. Po geomorfologickĂ©m a petrografickĂ©m studiu zájmovĂ© lokality analyzujeme souÄŤasnou faerskou legislativu zaměřenou na ochranu pĹ™Ărody a uĹľĂváme tohoto pĹ™Ăkladu k diskusi širšĂch dĹŻsledkĹŻ zachovánĂ a geoturistiky geografickĂ©ho dÄ›dictvĂ ve vzdálenĂ˝ch regionech
Imaging igneous intrusions in the lower crust on the Faroes and Hatton Bank margins using wide-angle Ocean Bottom Seismometer data.
Stacked seismic sections produced from wide-angle ocean bottom seismometers (OBS) show clear,
strong P-wave reflections interpreted as igneous intrusions arriving from lower crustal and upper
mantle depths on the Faroes margin. The lower-crustal reflectors are also seen on a coincident long-
offset multi-channel (MCS) profile, though the upper mantle reflections are a new observation.
Strong wide-angle reflections are also seen in OBS data from Hatton Bank profiles where no
corresponding MCS profiles were shot. Applying this technique to the Hatton Bank data will allow
us to image this section of the margin and determine if the structure seen in the Faroes MCS survey
is present at other locations along the margin. Producing such images with conventional MCS data
has proved difficult due to their necessarily limited offsets, and the presence of refractions and
multiples at offsets beyond the first break of the sea-bed reflection. Adapting this technique to the
OBS shear wave data may allow us for the first time to image sub-basalt structure with converted
shear waves. Our results demonstrate the benefit of imaging wide-angle OBS data, since many OBS
surveys have been employed solely to perform travel-time inversions. The data come from the
integrated Seismic Imaging and Modelling of Margins (iSIMM) project shot in 2002 with wide-
angle OBS surveys northeast of the Faroe Islands and across Hatton Bank. These areas contain
flood basalts of the North Atlantic Igneous Province, making conventional seismic imaging
challenging
Additional file 6 of Qualitative longitudinal research in health research: a method study
Additional file 6. Datase
Qualitative longitudinal research in health research: a method study
Abstract Background Qualitative longitudinal research (QLR) comprises qualitative studies, with repeated data collection, that focus on the temporality (e.g., time and change) of a phenomenon. The use of QLR is increasing in health research since many topics within health involve change (e.g., progressive illness, rehabilitation). A method study can provide an insightful understanding of the use, trends and variations within this approach. The aim of this study was to map how QLR articles within the existing health research literature are designed to capture aspects of time and/or change. Methods This method study used an adapted scoping review design. Articles were eligible if they were written in English, published between 2017 and 2019, and reported results from qualitative data collected at different time points/time waves with the same sample or in the same setting. Articles were identified using EBSCOhost. Two independent reviewers performed the screening, selection and charting. Results A total of 299 articles were included. There was great variation among the articles in the use of methodological traditions, type of data, length of data collection, and components of longitudinal data collection. However, the majority of articles represented large studies and were based on individual interview data. Approximately half of the articles self-identified as QLR studies or as following a QLR design, although slightly less than 20% of them included QLR method literature in their method sections. Conclusions QLR is often used in large complex studies. Some articles were thoroughly designed to capture time/change throughout the methodology, aim and data collection, while other articles included few elements of QLR. Longitudinal data collection includes several components, such as what entities are followed across time, the tempo of data collection, and to what extent the data collection is preplanned or adapted across time. Therefore, there are several practices and possibilities researchers should consider before starting a QLR project
Additional file 6 of Qualitative longitudinal research in health research: a method study
Additional file 6. Datase
Qualitative longitudinal research in health research: a method study
Abstract Background Qualitative longitudinal research (QLR) comprises qualitative studies, with repeated data collection, that focus on the temporality (e.g., time and change) of a phenomenon. The use of QLR is increasing in health research since many topics within health involve change (e.g., progressive illness, rehabilitation). A method study can provide an insightful understanding of the use, trends and variations within this approach. The aim of this study was to map how QLR articles within the existing health research literature are designed to capture aspects of time and/or change. Methods This method study used an adapted scoping review design. Articles were eligible if they were written in English, published between 2017 and 2019, and reported results from qualitative data collected at different time points/time waves with the same sample or in the same setting. Articles were identified using EBSCOhost. Two independent reviewers performed the screening, selection and charting. Results A total of 299 articles were included. There was great variation among the articles in the use of methodological traditions, type of data, length of data collection, and components of longitudinal data collection. However, the majority of articles represented large studies and were based on individual interview data. Approximately half of the articles self-identified as QLR studies or as following a QLR design, although slightly less than 20% of them included QLR method literature in their method sections. Conclusions QLR is often used in large complex studies. Some articles were thoroughly designed to capture time/change throughout the methodology, aim and data collection, while other articles included few elements of QLR. Longitudinal data collection includes several components, such as what entities are followed across time, the tempo of data collection, and to what extent the data collection is preplanned or adapted across time. Therefore, there are several practices and possibilities researchers should consider before starting a QLR project