2,378 research outputs found
ILWIS GIS for Monitoring Landscapes in Tundra Ecosystems: Yamal Peninsula, Russia
No full textThe paper focuses on the monitoring changes in Russian tundra landscapes and distribution of various land cover types in Yamal Peninsula, Russia, during the past two decades. Specific climate and environmental settings of the study area facilitate seasonal flooding, active erosion processing, permafrost distribution and local landslide formation. Technically, the research has been performed using ILWIS GIS applied for satellite images comparative analysis using GIS supervised classification methods.P. Lemenkova, B. Forbes, and T. Kumpula. "ILWIS GIS for Monitoring Landscapes in Tundra Ecosystems: Yamal Peninsula, Russia". In: Remote Sensing and Global Surveillance. 3rd Inter- national Geosciences Student Conference (Association of Geophysicists and Environmentalists of Serbia (AGES), May 29–31, 2012). Serbia, Belgrade, 2012. isbn: 978-86-913953-5-3. doi: 10.6084/m9.figshare.7434236.v1
Vegetation::structure, cover and biomass of subarctic tundra wetlands used as summer pastures
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History sketch 157th Engineer (C) Bn.
No full textThis is a historical description of the 157th Engineer (C) Battalion written from memory by author. Notes are not attached as described on last page of document
Learning Phonological Grammars for Output-Driven Maps
No full textThe challenge of simultaneously learning a lexicon of underlying forms and a constraint ranking has been addressed by several scholars in recent work (Apoussidou 2007, Jarosz 2006, Merchant 2008, Tesar 2006). In particular, the proposal of Merchant, the Contrast Pair and Ranking information algorithm (CPR), avoids having to explicitly enumerate all possible underlying forms for each morpheme (in contrast to Apoussidou and Jarosz), and also avoids having to explicitly enumerate all possible constraint rankings (in contrast to Jarosz).
While CPR avoids those computational traps, there are still some components of CPR (and of the related work by Tesar) that pose computational difficulties. (1) The focus of CPR on lexical hypotheses for only a pair of related words at a time (a contrast pair) is a vast improvement over simultaneous consideration of all possible lexica, but the space of lexical hypotheses for a single contrast pair still grows exponentially in the number of unset underlying features for the morphemes involved in the pair. (2) The technique of initial lexicon construction, setting in advance features that do not alternate, can restrict further the number of lexical hypotheses that need to be considered, but at the cost of requiring that the learner have a complete paradigm of surface form data before learning of underlying forms can begin. (3) The extraction of ranking information performed by CPR is able to obtain ranking information from contrast pairs for which complete underlying forms have not yet been determined, but also faces exponential computational complexity, due in part to the fact that the procedure is separately computing the ranking implications of each lexical hypothesis in the (exponentially growing) set of possible hypotheses for the contrast pair.
The current paper demonstrates that each of these computational concerns can be significantly improved upon by taking the structure of grammars into greater consideration. The key grammatical structure lies in Tesar's proposal of output-driven map (Tesar 2008). Intuitively, an output-driven map is a phonological map in which all disparities introduced between the input and the output are motivated by conditions on the output. This notion is formalized by the requirement that any grammatical input-output mapping A->C entails the grammaticality of B->C whenever B has 'greater similarity' to C than A does (A->C has every input-output disparity that B->C does, but B->C may lack some disparities of A->C). An output-driven map is necessarily a restricted identity map (Prince and Tesar 2004), meaning that every grammatical form maps to itself, a property assumed to hold of grammars in much learnability work, including that of Merchant. Output-driven maps can be viewed as a strengthened version of restricted identity maps.
The structure of output-driven maps can be exploited in learning via the contrapositive: B~->C entails A~->C. Given a grammatical output C, it is a given that C->C (restricted identity map property). Suppose B has one disparity with C (e.g., they differ in the value of one feature on one segment). If the learner possesses sufficient information to determine that B cannot map to C, then the learner need not bother checking to see if A maps to C; because the map is output-driven, any input which has, relative to C, all of the disparities of B plus additional ones cannot be grammatical. All lexical hypotheses which include all of the disparities of B->C may be dismissed without evaluation. Instead of needing to evaluate all combinations of possible values for all unset features of a word (exponential in the number of unset features), the learner can obtain the same information while only evaluating a single unset feature at a time (linear in the number of unset features), having the other unset features match (temporarily) the values of their output correspondents, addressing concern (1). If a word has eight unset binary features, this means evaluating 8 lexical hypotheses instead of 256. Even greater benefit is realized when obtaining ranking information from forms with unset features, addressing concern (3).
The speed-up realized by exploiting the structure of output-driven maps is significant enough that initial lexicon construction is no longer needed. This frees the learner from needing an entire paradigm before learning commences; the learner can begin learning about underlying forms from even a single datum, addressing concern (2). This algorithm has the notable property that features of underlying forms which cannot be shown to require a particular value remain unset; non-contrastive features are never set, without any need for the learner to separately construct an 'inventory of contrastive features'.The definitive version of this paper is published in NELS 39: Proceedings of the 39th Annual Meeting of the North East Linguistic Society (2011
Synthesis:Environmental and sociopolitical conditions for modern reindeer management in Europe's North
No full textILWIS GIS for Monitoring Landscapes in Tundra Ecosystems: Yamal Peninsula, Russia
No full textBrief Summary • distribution of various land cover types in Yamal Peninsula • monitoring changes in tundra landscapes • analysis of the landscape dynamics during the past two decades (1988-2011). Data: Landsat TM scenes for 1988 and 2011 years. Originality: Application of ILWIS GIS spatial analysis tools and Landsat imagery for Bovanenkovo region in Yamal. Methodology Technical tools: The RS data processing was performed in ILWIS GIS software. Research method: Image interpretation applied to Landsat TM scenes, and supervised classification. Geographic location: Yamal Peninsula, north Russia. Yamal Peninsula: geomorphology Specific climatic-environmental settings of Yamal Peninsula: flat geomorphology, elevations < 90 m. Processes: • seasonal flooding, • active erosion processing, • permafrost distribution and • intensive local landslides formation. Yamal Peninsula: environmental settings One of the typical process in Yamal tundra: cryogenic landslides. Landslides affect local ecosystem structure, because they change vegetation types recovering after the disaster. Image classification • The key research method is supervised classification (Minimal Distance), which is based on the spatial analysis of spectral signatures of object variables, i.e. vegetation types. • The classes sampling was performed using Sample Set tool in ILWIS GIS. • The training pixels for each land cover type were selected as representative samples and stored as classification key. • Requirement for training pixels: they have contrasting colors, visually visible and distinguishable on the image. Thematic mapping Layouts of main research results represent maps of the land cover classes. The created domain Land classes includes legend with representation colors visualizing each category. Environmental Analysis Results show: • overall increase of woody vegetation (willows and shrubs) • decrease of peatlands, grass and heath areas. This illustrates environmental process of greening in Arctic, i.e. the unnatural increase of woody plants. The gradual changes in patterns and distribution of plant species affect landscape structure in Yamal. Triggering factors: • complex environmental changes in Arctic • local cryogenic processes (e.g. successive change in vegetation recovering after cryogenic landslides
Mapping Land Cover Changes Using Landsat TM: A Case Study of Yamal Ecosystems, Arctic Russia
No full textThis paper details changes in land cover types and vegetation distribution in tundra landscapes during the past two decades. The main method of the work is classification of the Landsat TM scenes for land cover change detection. The new approach of the current work is application of GIS and remote sensing tools for Bovanenkovo region, since there is no previous remote sensing and GIS-based studies performed in the same area focusing research problem of land cover changes. The research area is geographically located on the Bovanenkovo region, the north-western part of Yamal Peninsula, West Siberia, Russia. The Yamal Peninsula is the world’s largest high-latitude wetland system covering in total 900,000 km² of peatlands, since lowland region creates ideal conditions for the development of wetlands, dense lake and river network (Kremenetski et al. 2003). The geomorphology of Yamal Peninsula is flat homogeneous land and low-lying plains with maximal elevations lower than 90 meters (Walker et al. 2009). Such environmental settings of Yamal facilitate seasonal flooding, active erosion processing, permafrost distribution and intensive local landslides formation.The dominating vegetation types on Yamal include different types of shrubs and willows, heath, grasses, moss, and lichens. Changes in land cover types in the Russian North are caused by various reasons. These include multiple ecological and social factors, such as permafrost degradation, reindeer grazing and gas-field development, as well as overall environmental changes, including climate (Walker et al. 2009). One of the factors causing changes in vegetation types in landslide formation. Thus, the early-stage vegetation, such as pioneering mosses or lichens usually follows recent landslide formation, while meadows and willow shrubs with high canopy points indicate later stages of vegetation regeneration after landslide activities. Therefore, distribution of the willow shrubs on bare slopes may indicate that these areas were landslide-affected in the past (Ukraintseva and Leibman, 2007; Leibman and Kizyakov, 2007). Current research focuses on application of remote sensing data and GIS methods for land cover change detection in Bovanenkovo region. Technically, the data processing was performed in ILWIS GIS, using methods of image interpretation and supervised classification applied for Landsat TM scenes (1988 and 2011). The classification results indicate changes in land cover types in Yamal ecosystems, namely, the overall increase in woody plants, such as willows and shrub tundra (e.g. "short shrub tundra", "sparse short shrub tundra" and "dry short shrub tundra"), and slight decrease in grasses, heath and peatland. The main detected trend in these changes demonstrates process of greening in Arctic tundra, which indicates structural variations in ecosystems within the Bovanenkovo district. These changes can be explained by the complex ecological processes as well as anthropogenic influence, caused by Bovanenkovo gas field exploration and its consequences.P. Lemenkova, B. Forbes, and T. Kumpula. "Mapping Land Cover Changes Using Landsat TM: A Case Study of Yamal Ecosystems, Arctic Russia". In: Theoretical and Applied Aspects. Proceedings of 11th International Conference on Geoinformatics (Great Conference Hall of the National Academy of Sciences of Ukraine, May 14–17, 2012). Ukraine, Kiev, 2012. doi: 10.6084/m9.figshare.7434242.v1. url: https://elibrary.ru/item.asp?id=24527736
Bruce Mayne Stars
No full textPhotograph used for a story in the Daily Oklahoman newspaper. Caption: "Gaslight Dinner Theatre's version of "The Impossible Years" arrives from Raleigh, N. C. Starring is Bruce Mayne, an actor with 125 productions to his credit. In this production coming to OKC, Mayne plays Dr. Kingsley, author of a best-selling book, and busy preparing another volume, based on a study of teenage sexual behavior.
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