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Baker, Matthew S. "Skyline." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/46.
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Enclosed herein, in accordance with the requirements of the Department of English, College of Humanities and Sciences, and the VCU Graduate School, Virginia Commonwealth University, Richmond, Virginia, regarding thesis submission, arrangement, and abstraction, is the novel entitled Skyline, in which one Jameson Price, of Fredericksburg, Virginia, aged 19, embarks upon a journey of self-exploration, financial gain, and physical labor, and experiences for the first time (or maybe second) the tumults of love. Upon his enrolment in the Civilian Conservation Corps (CCC) in 1936, he is taken to Camp Saddleback, near New Puckett, Virginia, situated on the Blue Ridge Mountains to the east of the Shenandoah Valley. Here he assists in the creation of the Shenandoah National Park, and develops and explores relationships with fellow CCC boys and local residents—both positive and negative relationships, all with consequences that will affect all of their lives, forever.
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Gozzoli, Gianluca. "Geometric Gamma-skyline: un metodo efficiente per la computazione di skyline su dati aggregati." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/5036/.
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Kamnang, Wanko Patrick. "Optimisation des requêtes skyline multidimensionnelles." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0010/document.
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Dans le cadre de la sélection de meilleurs éléments au sein d’une base de données multidimensionnelle, plusieurs types de requêtes ont été définies. L’opérateur skyline présente l’avantage de ne pas nécessiter la définition d’une fonction de score permettant de classer lesdits éléments. Cependant, la propriété de monotonie que cet opérateur ne présente pas, rend non seulement (i) difficile l’optimisation de ses requêtes dans un contexte multidimensionnel, mais aussi (ii) presque imprévisible la taille du résultat des requêtes. Ce travail se propose, dans un premier temps, d’aborder la question de l’estimation de la taille du résultat d’une requête skyline donnée, en formulant des estimateurs présentant de bonnes propriétés statistiques(sans biais ou convergeant). Ensuite, il fournit deux approches différentes à l’optimisation des requêtes skyline. La première reposant sur un concept classique des bases de données qui est la dépendance fonctionnelle. La seconde se rapprochant des techniques de compression des données. Ces deux techniques trouvent leur place au sein de l’état de l’art comme le confortent les résultats expérimentaux.Nous abordons enfin la question de requêtes skyline au sein de données dynamiques en adaptant l’une de nos solutions précédentes dans cet intérêtAs part of the selection of the best items in a multidimensional database,several kinds of query were defined. The skyline operator has the advantage of not requiring the definition of a scoring function in order to classify tuples. However, the property of monotony that this operator does not satify, (i) makes difficult to optimize its queries in a multidimensional context, (ii) makes hard to estimate the size of query result. This work proposes, first, to address the question of estimating the size of the result of a given skyline query, formulating estimators with good statistical properties (unbiased or convergent). Then, it provides two different approaches to optimize multidimensional skyline queries. The first leans on a well known database concept: functional dependencies. And the second approach looks like a data compression method. Both algorithms are very interesting as confirm the experimental results. Finally, we address the issue of skyline queries in dynamic data by adapting one of our previous solutions in this goal
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Fu, Gregory Chung Yin. "Skyline queries in database systems /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?COMP%202003%20FU.
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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.Includes bibliographical references (leaves 51-52). Also available in electronic version. Access restricted to campus users.
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Gudala, Satyaveer Goud. "Skyline queries for multi-criteria decision support systems." Kansas State University, 2011. http://hdl.handle.net/2097/13250.
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Master of ScienceDepartment of Computing and Information Sciences
William H. Hsu
In decision-making applications, the Skyline query is used to find a set of non-dominated data points (called Skyline points) in a multi-dimensional dataset. A data point dominates another data point if it is at least as good as the other data point in all dimensions and better in at least one dimension. The skyline consists of data points not dominated by any other data point. Computing the skyline points of a dataset is essential for applications that involve multi-criteria decision making. Skyline queries filter out the interesting tuples from a potentially large dataset. No matter how we weigh our preferences along the attributes, only those tuples which score best under a monotone scoring function are part of the skyline. In other words, the skyline does not contain tuples which are nobody's favorite. With a growing number of real-world applications involving multi-criteria decision making over multiple dimensions, skyline queries can be used to answer those problems accurately and efficiently. This report mainly focuses on various skyline computing algorithms which can be used for online processing efficiently and are suitable to present multi-criteria decision making scenario. I implemented the Branch-and-Bound skyline Algorithm on two different data sets; one is a synthetic dataset and the other is a real dataset. My aim is to explore various subspaces of a given dataset and compute skylines over them, especially those subspace skylines which contain the least number of the skyline points.
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Miller, Nathan D. "Adapting the Skyline Operator in the NetFPGA Platform." Youngstown State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1369586333.
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Elmi, Saïda. "An Advanced Skyline Approach for Imperfect Data Exploitation and Analysis." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2017. http://www.theses.fr/2017ESMA0011/document.
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Ce travail de thèse porte sur un modèle de requête de préférence, appelée l'opérateur Skyline, pour l'exploitation de données imparfaites. L'imperfection de données peut être modélisée au moyen de la théorie de l'évidence. Ce type de données peut être géré dans des bases de données imparfaites appelées bases de données évidentielles. D'autre part, l'opérateur skyline est un outil puissant pour extraire les objets les plus intéressants dans une base de données.Dans le cadre de cette thèse, nous définissons une nouvelle sémantique de l'opérateur Skyline appropriée aux données imparfaites modélisées par la théorie de l'évidence. Nous introduisons par la suite la notion de points marginaux pour optimiser le calcul distribué du Skyline ainsi que la maintenance des objets Skyline en cas d'insertion ou de suppression d'objets dans la base de données.Nous modélisons aussi une fonction de score pour mesurer le degré de dominance de chaque objet skyline et définir le top-k Skyline. Une dernière contribution porte sur le raffinement de la requête Skyline pour obtenir les meilleurs objets skyline appelés objets Etoile ou Skyline starsThe main purpose of this thesis is to study an advanced database tool named the skyline operator in the context of imperfect data modeled by the evidence theory. In this thesis, we first address, on the one hand, the fundamental question of how to extend the dominance relationship to evidential data, and on the other hand, it provides some optimization techniques for improving the efficiency of the evidential skyline. We then introduce efficient approach for querying and processing the evidential skyline over multiple and distributed servers. ln addition, we propose efficient methods to maintain the skyline results in the evidential database context wben a set of objects is inserted or deleted. The idea is to incrementally compute the new skyline, without reconducting an initial operation from the scratch. In the second step, we introduce the top-k skyline query over imperfect data and we develop efficient algorithms its computation. Further more, since the evidential skyline size is often too large to be analyzed, we define the set SKY² to refine the evidential skyline and retrieve the best evidential skyline objects (or the stars). In addition, we develop suitable algorithms based on scalable techniques to efficiently compute the evidential SKY². Extensive experiments were conducted to show the efficiency and the effectiveness of our approaches
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Srivastava, Shweta. "Look Before You Leap: An Adaptive Processing Strategy For Multi-Criteria Decision Support Queries." Digital WPI, 2011. https://digitalcommons.wpi.edu/etd-theses/190.
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In recent years, we have witnessed a massive acquisition of data and increasing need to support multi-criteria decision support (MCDS) queries efficiently. Pareto-optimal also known as skyline queries is a popular class of MCDS queries and has received a lot of attention resulting in a flurry of efficient skyline algorithms. The vast majority of such algorithms focus entirely on the input being a single data set. In this work, we provide an adaptive query evaluation technique --- AdaptiveSky that is able to reason at different levels of abstraction thereby effectively minimizing the two primary costs, namely the cost of generating join results and the cost of dominance comparisons to compute the final skyline of the join results. Our approach hinges on two key principles. First, in the input space -- we determine the abstraction levels dynamically at run time instead of assigning a static one at compile time that may or may not work for different data distributions. This is achieved by adaptively partitioning the input data as intermediate results are being generated thereby eliminating the need to access vast majority of the input tuples. Second, we incrementally build the output space, containing the final skyline, without generating a single join result. Our approach is able to reason about the final result space and selectively drill into regions in the output space that show promise in generating result tuples to avoid generation of results that do not contribute to the query result. In this effort, we propose two alternate strategies for reasoning, namely the Euclidean Distance method and the cost-benefit driven Dominance Potential method for reasoning. Our experimental evaluation demonstrates that AdaptiveSky shows superior performance over state-of-the-art techniques over benchmark data sets.
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Samara, Rafat. "TOP-K AND SKYLINE QUERY PROCESSING OVER RELATIONAL DATABASE." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH. Forskningsmiljö Informationsteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-20108.
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Top-k and Skyline queries are a long study topic in database and information retrieval communities and they are two popular operations for preference retrieval. Top-k query returns a subset of the most relevant answers instead of all answers. Efficient top-k processing retrieves the k objects that have the highest overall score. In this paper, some algorithms that are used as a technique for efficient top-k processing for different scenarios have been represented. A framework based on existing algorithms with considering based cost optimization that works for these scenarios has been presented. This framework will be used when the user can determine the user ranking function. A real life scenario has been applied on this framework step by step. Skyline query returns a set of points that are not dominated (a record x dominates another record y if x is as good as y in all attributes and strictly better in at least one attribute) by other points in the given datasets. In this paper, some algorithms that are used for evaluating the skyline query have been introduced. One of the problems in the skyline query which is called curse of dimensionality has been presented. A new strategy that based on the skyline existing algorithms, skyline frequency and the binary tree strategy which gives a good solution for this problem has been presented. This new strategy will be used when the user cannot determine the user ranking function. A real life scenario is presented which apply this strategy step by step. Finally, the advantages of the top-k query have been applied on the skyline query in order to have a quickly and efficient retrieving results.
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Zhang, Shiming, and 张世明. "Scalable skyline evaluation in multidimensional and partially ordered domains." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46973916.
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Plentz, Samuel. "Skyline-Anfragen für die multidimensionale Suche in einer Aktordatenbank." [Ilmenau] [Univ.-Bibliothek], 2009. http://d-nb.info/995970955/34.
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Miyata, Edwin S. "An investigation of the monocable system for cable yarding of small, low-value trees on steep, difficult sites /." Thesis, Connect to this title online; UW restricted, 1991. http://hdl.handle.net/1773/7061.
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Hughes, Daniel. "Breaking up the traditional skyline : writing modernist Wales in English." Thesis, Bangor University, 2018. https://research.bangor.ac.uk/portal/en/theses/breaking-up-the-traditional-skyline-writing-modernist-wales-in-english(3e242f73-4dec-41cf-9606-b7c4ef1ef925).html.
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Across the work of eleven key authors — Caradoc Evans, Gwyn Thomas, Glyn Jones, Nigel Heseltine, Dylan Thomas, Lynette Roberts, David Jones, Dorothy Edwards, Margiad Evans, Brenda Chamberlain, and Tony Conran — this thesis analyses the output of an Anglophone cultural formation of modernist writers in Wales, whose literature comprise a major — yet neglected — strand of European modernism. The introductory chapter engages with the history of the idea of ‘Modernism’, and the current state of modernist studies within and beyond Wales, arguing that conventional notions of ‘Modernism’ as a fixed, monolithic period confined to the major metropolitan areas of Europe and America are no longer sufficient in light of recent developments in the field. The second chapter examines the controversial writer Caradoc Evans, once considered the ‘father’ of what was commonly called ‘Anglo-Welsh’ literature, whose incendiary 1915 short story collection My People serves as the explosive genesis of Anglophone Welsh modernism. I compare Evans’s work with a later author, Gwyn Thomas, whose 1946 novella Oscar depicts a nihilistic void under the guise of a bleak South Walian valley. Across the following two chapters, I explore the work of writers connected to a cultural formation of Anglophone Welsh modernist writers, utilising the term ‘formation’ as conceptualised by Raymond Williams in Culture (1981). This ‘formation’ occupied the cultural space cleared by Caradoc Evans, used Wales as their social and literary nexus (the magazine was edited by their mutual friend, Keidrych Rhys) and included in their number key writers examined in the thesis, such as Glyn Jones, Nigel Heseltine, Dylan Thomas, Lynette Roberts, and David Jones. In the fifth chapter, I analyse the ‘Gothic Wastelands’ of two recently recovered women writers, Margiad Evans and Dorothy Edwards, who were tangentially connected to the formation. In the sixth chapter, the thesis explores the modernist life-writing of Brenda Chamberlain and Tony Conran, as well as their position as the last members of this particular cultural formation. Finally, the thesis concludes by asking a question which becomes increasingly obvious in the face of the strength, vitality and diversity of Welsh modernism as demonstrated by this thesis: what brings us here so late?
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Lampariello, Laura. "Indicatori originali per caratterizzare la rilevanza dei punti dello Skyline." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022.
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La quantità sempre crescente di informazioni disponibili è uno dei maggiori problemi dei sistemi informativi di oggi. Oltre a restituire velocemente i risultati dell’interrogazione, è fondamentale fornire un accesso personalizzato e su misura all’utente finale.
Poiché gli attuali sistemi in uso (Query Top-k) presentano delle indubbie limitazioni, cioè non riescono fedelmente a interpretare i desideri dell’utente, si introducono per la prima volta dei nuovi indicatori. Questi nuovi indicatori, applicati ai punti estratti, caratterizzano tutti quei casi di “buon compromesso” che sono difficili da recuperare con interrogazioni Top-k. Essi vengono costruiti sui risultati di un’altra tipologia di interrogazione (Query Skyline) che non viene attualmente usata nei sistemi commerciali.
Gli originali indicatori, introdotti qui per la prima volta, sono tre: indice di concavità, robustezza alla griglia e incremento del volume di dominazione.
I risultati di questa trattazione potranno essere oggetto di lavori futuri volti all’ideazione di un nuovo e più valido tipo di query che possa sostituire più efficacemente quelle attuali.
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Alami, Karim. "Optimisation des requêtes de préférence skyline dans des contextes dynamiques." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0135.
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Les requêtes de préférence sont des outils intéressants pour calculer des sous-ensembles représentatifs d'ensembles de données en entrée ou pour classer les tuples en fonction des préférences des utilisateurs. Dans cette thèse, nous abordons principalement l'optimisation des requêtes Skyline, une classe spéciale des requêtes de préférence, dans des contextes dynamiques. Dans une première partie, nous abordons la maintenance incrémentale de la structure d'indexation multidimensionnelle NSC qui a été démontrée efficace pour répondre aux requêtes skyline dans un contexte statique. Plus précisément, nous abordons (i) le cas des données dynamiques, c'est-à-dire que des tuples sont insérés ou supprimés à tout moment, et (ii) le cas des données en streaming, c'est-à-dire que les tuples sont insérés et écartés après un intervalle de temps spécifique. En cas de données dynamiques, nous repensons la structure et proposons des procédures pour gérer efficacement les insertions et les suppressions. En cas de données en streaming, nous proposons MSSD un pipeline de données qui gère les données par lot et maintient NSCt une variation de NSC. Dans une deuxième partie, nous abordons le cas des ordres dynamiques, c'est-à-dire que certains ou tous les attributs de l'ensemble de données sont catégoriques et chaque utilisateur exprime son propre ordre partiel sur le domaine de ces attributs. Nous proposons des algorithmes parallèles évolutifs qui décomposent une requête en un ensemble de sous-requêtes et traitent chaque sous-requête indépendamment. Pour optimiser davantage, nous proposons la matérialisation partielle des sous-requêtes et introduisons le problème de la sélection de sous-requêtes en fonction d'un coûtPreference queries are interesting tools to compute small representatives of datasets or to rank tuples based on the users’ preferences. In this thesis, we mainly focus on the optimization of Skyline queries, a special class of preference queries, in dynamic contexts. In a first part, we address the incremental maintenance of the multidimensional indexing structure NSC which has been shown efficient for answering skyline queries in a static context. More precisely, we address (i) the case of dynamic data, i.e. tuples are inserted or deleted at any time, and (ii) the case of streaming data, i.e. tuples are appended only, and discarded after a specific interval of time. In case of dynamic data, we redesign the structure and propose procedures to handle efficiently both insertions and deletions. In case of streaming data, we propose MSSD a data pipeline which operates in batch mode, and maintains NSCt a variation of NSC. In a second part, we address the case of dynamic orders, i.e, some or all attributes of the dataset are nominal and each user expresses his/her own partial order on these attributes’ domain. We propose highly scalable parallel algorithms that decompose an issued query into a set of sub-queries and process each sub-query independently. In a further step for optimization, we propose the partial materialization of sub-queries and introduce the problem of cost-driven sub-queries selection
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Curtis, Anthony Patrick. "Warriors of the skyline a gendered study of Mohawk warrior culture /." Huntington, WV : [Marshall University Libraries], 2005. http://www.marshall.edu/etd/descript.asp?ref=516.
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Levy, David Alan. "The sacred skyline : the conflict over height restrictions for Copley Square." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/75965.
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Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning; and, (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1985.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH.
Bibliography: leaves 131-132.
by David Alan Levy.
M.C.P.
M.S.
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Fuhry, David P. "Skylines in Metric Space." Kent State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=kent1208562156.
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Ayadi, Mehdi. "Skyline : un marqueur pour la réalité augmentée sur mobile en contexte urbain." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE2051.
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L’objectif principal de cette thèse consiste à proposer une approche qui permet à un utilisateur se déplaçant en milieu urbain, de visualiser en Réalité Augmentée, à l’aide d’un smartphone, l’incidence d’un projet de construction sur le paysage urbain, une fois le bâtiment réalisé. En particulier, avec le retour actuel des projets de constructions de tours dans les grandes villes (Londres, Paris et Lyon notamment), il devient un enjeu très important pour les usagers des quartiers de pouvoir se rendre compte visuellement de l’impact d’un projet de construction sur la ligne d’horizon (Skyline) et donner un avis le plus objectif possible sur un projet de construction. Du point de vue des géographes et des usagers des quartiers, ce dispositif innovant permet de prendre le contrepied des cabinets d’architectes, qui ne proposent que des rendus très esthétiques de leurs projets de construction, avec nombre limité de vues, au détriment de visualisations plus objectives. Il ne s’agit pas nécessairement de proposer un rendu photo-réaliste, mais plutôt une esquisse la plus exacte possible de la géométrie de la scène, tout au long de la déambulation de l’usager. Des visualisations à différentes positions et orientations correspondent mieux aux usages les plus courants de la vie dans les quartiers. Nous proposons une approche dans laquelle les différentes données issues de la multitude d’instruments embarquées dans le dispositif sont fusionnées, afin d’estimer la pose de l’appareil : le compas magnétique permet d’estimer la direction d’observation; le gyroscope et l’accéléromètre permettent d’évaluer grossièrement les paramètres de mouvement (trois degrés deliberté en translation, et trois degrés de liberté en rotation). Cette première pose estimée, associée au modèle 3D de la ville, permet, à l’aide des supports de rendu (2D et 3D) des dispositifs, de générer une image de synthèse de ce que l’utilisateur visualise théoriquement à cette position. Néanmoins, l’utilisation unique de ces instruments pour insérer un objet de synthèse dans le flux vidéo donne à l’utilisateur une impression très peu réaliste de la scène qu’il visionne : les objets de synthèse semblent «flotter » au gré des mouvements en raison des imprécisions des instruments. Pour pallier ce défaut, le skyline est extrait automatiquement des images réelles (acquises par la caméra) et virtuelles (générées). Une étape d’appariement des deux skylines permet de recaler le skyline virtuel sur le réel et ainsi permettre une incrustation entemps réel des projets de construction au sein du flux vidéo, et une amélioration selon deux critères : précision et stabilité avec une impression d’immersion bien meilleure. Plusieurs mesures de similarité sont proposées avec une approche d’optimisation basée sur une descente de gradientThe main objective of this thesis is to propose an approach that allows a user, moving in an urban environment, to visualize in augmented reality, using a smartphone, the impact of a construction project on the urban landscape, once thebuilding is completed. In particular, with the current attractivity for tower construc tion projects in major cities (London, Paris and Lyon in particular), it is becoming a very important issue for neighborhood users to be able to visualize the impact of aconstruction project on the skyline and to give an objective opinion on it. For geographers and neighborhood users, this innovative solution makes it possible to take the opposite view from architectural firms, which only offer very qualitative renderings of their construction projects, with a limited number of views, to the detriment of more objective visualizations. We do not necessarily propose a photo-realistic rendering, but rather a more exact geometric consistency of the scene, throughout the user’s movements. Visualizations at different positions and orientations correspond better to common use cases in neighborhoods. We propose an approach in which data from smartphone’s embedded instruments are merged to estimate a first user’s pose : the magnetic compass estimates the viewing direction; the GPS, gyroscope and accelerometer roughly evaluate the parameters of motion (three degrees of freedom in translation, and three degrees of freedom in rotation). This first estimated pose, associated with the 3D model of the city, allows, using the rendering supports (2D and 3D) of the devices, to generate a synthetic image of what the user theoretically visualizes at this position. Nevertheless, the unique use of these instruments to insert a synthetic object into the video stream gives the user a very unrealistic impression ofthe viewed scene : due to instrument’s data inaccuracies, synthetic objects appear to “hover” and "float" with the user’s movements. For this, the skyline is automatically extracted from real (acquired by the camera) and virtual (generated) images. A matching step between the two skylines allows to realign the virtual skyline onto the real one, allowing thus a real time insertion of the 3D object in the real-time video stream, and an improvement according to two criteria : precision and stability, giving with a much better immersion impression. In this matching step, several similarity metrics are proposed that are used in an optimization approach based on a gradient descent
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Nuske, Samuel Ryan. "A comparative study of mechanized cable harvesting systems in New Zealand." Thesis, University of Canterbury. School of Forestry, 2014. http://hdl.handle.net/10092/10471.
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Productivity and safety concerns of traditional cable harvesting systems have been the key drivers for increasing levels of mechanisation in New Zealand. The use of grapples in cable yarding could eliminate the need for motor-manual tree fallers and breaker-outs in most situations.
A comparative time study was carried out on two mechanised cable harvesting systems utilising grapple carriages in an attempt to better understand the benefits and limitations of each system in different harvest settings. These systems include the Mechanical system which involved a swing yarder operating a mechanical grapple carriage and the Motorised system, which used a tower yarder with a motorised grapple carriage.
The Mechanical system took less time to accumulate felled trees but took longer to unhook trees on the landing than the Motorised system. The Mechanical system had a shorter cycle time (2.07 minutes) than the Motorised system (2.32 minutes) and extracted 1.3 tonnes more than the Motorised system per cycle. The Motorised system had shorter cycle times when in horizontal haul distances of less than 90 metres, but had the longest times when the distance exceeded this. Utilisation rates were similar between the two systems, although the main difference in delays between the two systems was the use of surgepiles on the landing by the Motorised system.
Both systems were effective, although on average the Mechanical system was more productive, with a productivity of 45 t/SMH, compared to 40 t/SMH for the Motorised system. The Mechanical system was the most productive when extracting mechanically felled and pre-bunched or trees while the Motorised system was the most productive when extracting motor-manually felled trees. Pre-bunching with an excavator was a more cost effective method than handing stems directly to the grapple carriage. Further research of the Mechanical system under more adverse conditions would allow a better overall comparison.
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Yip, Kin-man Ernest, and 葉健文. "Developing a city skyline for Hong Kong using GIS and urban design guidelines." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B27049802.
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Cocoris, Constance. "Marking the skyline and viewing the city : a new building for Birmingham's Five Points South." Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/23908.
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Paß, Mario. "The New Skyline of Berlin : A 3D GIS shadow and visibility analysis at the Alexanderplatz." Thesis, Umeå universitet, Institutionen för geografi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-184742.
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The capital of Germany Berlin will undergo a change in its skyline in the next few years.Due to a new housing policy that allows the construction of higher buildings, Berlinwill soon have several skyscrapers over 130 m high directly at Alexanderplatz as wellas next the Berlin landmark, the Berlin TV Tower.With the help of ArcGIS, the newbuildings are shown in 3D along with the impact of these buildings on the view to theTV Tower and the shadows cast by the new buildings on the Alexanderplatz. It is shownthat due to the new buildings, some areas around the Alexanderplatz no longer have acomplete view to the TV Tower. The shadow cast by the buildings will only slightlychange the current shadow cast on the Alexanderplatz, but neighbouring areas aroundthe Alexanderplatz will now be affected more by shadows.
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Kuan-An, Hsieh, and 謝冠安. "Skyline." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/hr4w86.
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碩士東海大學
美術學系
107
“The skylines of cities” is the guideline of this thesis. The researcher explores the utopian imagination by adding the contradiction of social reality and urban architecture as the motivation and elements. This thesis aims to illustrate the spirit of urban shan shui and identify the metaphorical expressions and meanings of various signs and icons in the researcher’s art work. Chapter One will comprise what the researcher has learned and explicate the researcher’s motivation, purpose and offers the orientation and methods of this thesis. Chapter Two will reveal the impact of the Chinese painting (shui mo-art) and modern urban architecture under the contrast of modern high buildings and outskirts of cities. Chapter Three will explicate the insights of the researcher’s conception and argumentation and express the process and style of art work. Chapter Four will analyze the style and conception of every art work. Chapter Five will be the conclusion for self-inspection.
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Hsu, Wan-Ting, and 許菀庭. "Skyline Travel Route: Exploring Skyline for Travel Route Recommendation." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/352q7x.
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碩士國立交通大學
資訊科學與工程研究所
102
With the advance of location positioning technology and some geo-Web services (e.g., EveryTrail), users can easily use mobile Apps to record their travel experiences via photos and trip trajectories. Prior works have elaborated on trip planning in mining travel routes from a huge number of trajectories. However, most of the travel routes mined may have some overlapping Regions-Of-Interest (ROIs) information, which incur some redundant travel information. Moreover, each ROI may have its appropriate visiting time, and users may also have their own preferred must-see ROIs (referred to as a set of query points). The above two factors are not considered in prior works. Thus, in this paper, given a spatial range $Q$ and a set of query points specified by users, the goal of this paper is to return the travel routes that fulfill two requirements: 1.) travel routes should contain all those query points specified, and 2.) travel routes should be within the spatial range Q. Furthermore, we claim that each query point may have its proper visiting time. As such, the travel routes should go through these query points at their corresponding proper visiting time. To avoid some redundant information in the travel routes, we utilize the skyline concept to retrieve travel routes with more diversity. Specifically, in our paper, we consider some factors, such as the visiting time information of POIs and the set of query points, in retrieving travel routes. These factors could be mapped into dimensional spaces. Then, each travel route is viewed as a data point in the dimensional space. Thus, skyline data points (referred to as skyline travel routes) are returned as the query result. To evaluate our proposed methods, we conducted extensive experiments on real datasets. The experimental results show that skyline travel routes indeed provide more diversity in the query result. In addition, we evaluate the efficiency of retrieving skyline travel routes.
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Yang, Sheng-Fu, and 楊盛富. "Computing Skyline Efficiently on Uncertain Data According to Skyline Expected Value." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/53443023947322123332.
Full textAbstract:
碩士國立東華大學
資訊工程學系
101
Because the improvement of technology, the collecting of information is no longer limited to hardware, and many real applications may turn out to be used in uncertain data environments. Therefore, how to compute the needed information in such an environment efficiently is a very important problem. In this work, the idea of expected number of objects is introduced to represent as the scoring function of an object in the uncertain database. And the score associated with each object is called as CP value. By using the concept of CP value, we propose the efficient algorithms for finding the high-CP and Top-K objects. Simulation is performed on both syntactic and real datasets. The experimental results indicate that our approach is efficient and effective..
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Durston, Thomas A. "Improving the performance of multispan logging systems by suspending the mainline /." 1989. http://hdl.handle.net/1957/9492.
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"Distance-based representative skyline." 2009. http://library.cuhk.edu.hk/record=b5894005.
Full textAbstract:
Ding, Ling.Thesis (M.Phil.)--Chinese University of Hong Kong, 2009.
Includes bibliographical references (leaves [43]-45).
Abstract also in Chinese.
Thesis Committee --- p.i
Abstract --- p.ii
Acknowledgement --- p.iv
Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Background --- p.1
Chapter 1.2 --- Motivation --- p.3
Chapter 1.3 --- Thesis Organization --- p.4
Chapter 2 --- Representative Skylines and Basic Properties --- p.6
Chapter 2.1 --- Existing Formulation --- p.6
Chapter 2.1.1 --- Max-dominance Representative Skyline --- p.6
Chapter 2.1.2 --- Defects of the Existing Formulation --- p.7
Chapter 2.2 --- Our Formulation --- p.9
Chapter 2.2.1 --- Distance-based Representative Skyline --- p.9
Chapter 2.2.2 --- Properties of Our Formulation --- p.10
Chapter 2.3 --- Problem Definition --- p.12
Chapter 3 --- The Two-dimensional Case --- p.13
Chapter 3.1 --- Algorithm 2D-opt --- p.13
Chapter 3.2 --- Time Complexity --- p.15
Chapter 3.3 --- Computing Covering Circles --- p.15
Chapter 4 --- The Higher-dimensional Case --- p.18
Chapter 4.1 --- NP-hardness and 2-approximation --- p.18
Chapter 4.1.1 --- Proof of NP-hardness --- p.18
Chapter 4.1.2 --- Algorithm naive-greedy --- p.19
Chapter 4.2 --- Algorithm I-greedy --- p.20
Chapter 4.2.1 --- Conservative Skyline --- p.22
Chapter 4.2.2 --- Access Order --- p.23
Chapter 4.3 --- Computing the Maximum Representative Distance --- p.27
Chapter 5 --- Experiments --- p.30
Chapter 5.1 --- Data --- p.30
Chapter 5.2 --- Representation Quality --- p.31
Chapter 5.2.1 --- Representative Skylines --- p.31
Chapter 5.2.2 --- Representation Error Comparison --- p.33
Chapter 5.3 --- Efficiency --- p.34
Chapter 5.3.1 --- Running Time Comparison --- p.34
Chapter 5.3.2 --- Scalability Comparison --- p.37
Chapter 6 --- Related Work --- p.39
Chapter 7 --- Conclusions --- p.41
A List of Publications --- p.42
Bibliography --- p.43
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Chung, Woodam. "Optimization of cable logging layout using a heuristic algorithm for network programming /." 2002. http://hdl.handle.net/1957/9487.
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Jain, Romil. "Handling worst case in skyline /." 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR51543.
Full textAbstract:
Thesis (M.Sc.)--York University, 2009. Graduate Programme in Computer Science.Typescript. Includes bibliographical references (leaves 83-84). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR51543
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CHIU, SHENG-WEI, and 邱聖崴. "Approximate Patrolling Skyline Path Query." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/32774321458936209218.
Full textAbstract:
碩士逢甲大學
資訊工程學系
105
In this study, we formulated a novel route planning query referred to as the Patrolling Skyline Path Query. The term patrolling road refers to situations in which vehicles patrol a particular area and follow particular roads/routes according to a set schedule. For example, roads that require snowplow service are referred to as Patrolling roads. However, identifying these roads can be difficult, due to changes in the accumulation of snow over time and the need to take into account distance and time costs as well as issues related to safety. No existing search mechanism is able to deal with these kinds of variables. The following hard points must be addressed. (1) How can we identify patrolling roads efficiently? (2) How can we boost query speeds? (3) How can we minimize the number of detours? In this study, we developed two methods to address these issues. The first method uses an index model to reduce the time required to identify roads that have not been serviced for a extended period. We also developed a sub-network of roads to reduce the number of nodes and edges and thereby enhance the efficiency of conventional skyline path queries while prioritizing roads of importance to the largest number of users and taking into account the tolerance of users for detours. We also developed a variation of the proposed method based on the concept of spatial skyline queries to enable the exclusion of some roads from the patrol schedule in order to reduce the overall workload. Simulation results demonstrate that the second method is more efficient with regard to time costs and the accuracy of results.
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Charland, James W. "Analysis of intermediate support cable logging systems." Thesis, 1997. http://hdl.handle.net/1957/28782.
Full textAbstract:
The forest products industry often uses intermediate-support cable logging
systems to transport logs from the harvest site to a staging area. A method is presented to assist in the analysis and design of these cable systems. The method determines tensions in individual cables, forces on and stresses in the support trees, and the geometry of the system under load. Static equilibrium and cable length compatibility are used to generate a system of simultaneous equations. This system of coupled, non-linear algebraic equations is solved numerically using the Newton-Raphson algorithm. A good,
automated initial guess for the unknown quantities, based on the physics of the problem,
is provided. A model of an example intermediate support cable logging system is
analyzed by the proposed approach and the resulting behavior discussed. The method
includes the effects of catenary sag and elastic stretch in the cables, and elastic behavior in the support trees. Friction is ignored in the formulation. The catenary and elastic stretch methodologies for the cables are each demonstrated on a single cable span as well as on a demonstration cable system. The effect of the support tree flexibility and cable mass are found to be significant on the response of the cable logging system. The effects of elastic stretch in the cables is not found to be significant for the cable logging systems considered.Graduation date: 1997
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Yuan, Yidong Computer Science & Engineering Faculty of Engineering UNSW. "Efficient computation of advanced skyline queries." 2007. http://handle.unsw.edu.au/1959.4/40511.
Full textAbstract:
Skyline has been proposed as an important operator for many applications, such as multi-criteria decision making, data mining and visualization, and user-preference queries. Due to its importance, skyline and its computation have received considerable attention from database research community recently. All the existing techniques, however, focus on the conventional databases. They are not applicable to online computation environment, such as data stream. In addition, the existing studies consider efficiency of skyline computation only, while the fundamental problem on the semantics of skylines still remains open. In this thesis, we study three problems of skyline computation: (1) online computing skyline over data stream; (2) skyline cube computation and its analysis; and (3) top-k most representative skyline. To tackle the problem of online skyline computation, we develop a novel framework which converts more expensive multiple dimensional skyline computation to stabbing queries in 1-dimensional space. Based on this framework, a rigorous theoretical analysis of the time complexity of online skyline computation is provided. Then, efficient algorithms are proposed to support ad hoc and continuous skyline queries over data stream. Inspired by the idea of data cube, we propose a novel concept of skyline cube which consists of skylines of all possible non-empty subsets of a given full space. We identify the unique sharing strategies for skyline cube computation and develop two efficient algorithms which compute skyline cube in a bottom-up and top-down manner, respectively. Finally, a theoretical framework to answer the question about semantics of skyline and analysis of multidimensional subspace skyline are presented. Motived by the fact that the full skyline may be less informative because it generally consists of a large number of skyline points, we proposed a novel skyline operator -- top-k most representative skyline. The top-k most representative skyline operator selects the k skyline points so that the number of data points, which are dominated by at least one of these k skyline points, is maximized. To compute top-k most representative skyline, two efficient algorithms and their theoretical analysis are presented.
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林岳嶙. "Efficient Computation of Constrained Group Skyline." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/uzvt77.
Full textAbstract:
碩士逢甲大學
資訊工程學系
104
In recent years, the skyline query has been an important issue in the database community. Almost all of the traditional skyline algorithms compute the skyline result on a single tuple. However, in many real applications, some of them do not only consider the single tuple result, but also compute the skyline result by grouping tuples, such as advertising, fantasy sports, stock portfolio, and hackathon. This problem is called Group Skyline. The previous group skyline research has concerned combinations quantity and complicated skyline computation. The research has focused on the efficiency of the method. Assume that there are 1000 tuples and 3 tuples to form a group. In this case, there are about 1.7108 combinations needed to compute the group skyline result. However, none of the group skyline algorithms considers constraints. In the real world, sometimes the user selection will be limited by some constraint. For example, a company advertising needs to consider its limited budget. A group skyline result that considers a constraint called constrained group skyline. The main objective of this thesis is to propose two constrained group skyline algorithms, CGSky and CGSLayer. The first algorithm, CGSky, utilizes a pre-processing method to exclude the unnecessary tuples. Then, we utilize the incremental method to generate all candidate groups to compute the constrained group skyline. The second algorithm, CGSLayer, utilizes a pre-processing method to get the tuple dominance relationship. Then, we utilize the dominance information to generate all candidate groups. We also design a pre-filtering mechanism PFC to avoid the candidate groups that do not satisfy the constraint to join the skyline computation. Our experimental results show that our algorithms, CGSky and CGSLayer, are about ten-times faster than previous group skyline algorithm. Our experimental results also show that the algorithms on different data distributions and varying parameters have good computation efficiency.
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Chia-HengChang and 張嘉恒. "Continuous Skyline Queries in Road Networks." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/43915730531332275302.
Full textAbstract:
碩士國立成功大學
資訊工程學系碩博士班
98
The skyline query is an efficient tool for preference-based data analysis and attracts more attention than ever in the database community. Given a set of d-dimensional objects D, a skyline query retrieves all objects from D, which cannot be dominated by any others in D. In this paper, we investigate how to process the skyline query in road network, where the road distance between objects needs to be considered in query processing. Different from the previous related works, our work focuses on processing the continuous distance-based skyline query. We present two novel and important query types, named the Continuous d"-Skyline Query (Cd"-SQ for short) and the Continuous k nearest neighbor-Skyline Query (Cknn-SQ for short). To efficiently process the Cd"-SQ and Cknn-SQ in road network, we first design a grid index to manage the information of road network and objects, and then develop several algorithms combined with the grid index to determine the query result. Finally, we conduct a comprehensive set of experiments to demonstrate the effectiveness and the effciency of the proposed approaches.
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Lin, Yu-De, and 林育德. "Fully Skyline Computation on Data Streams." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/18696483958878315888.
Full textAbstract:
碩士銘傳大學
資訊工程學系碩士班
98
In Database field, Skyline concepts and techniques have caught many people''s attention and been widely used in various fields. In this study, we would use it in a very harsh condition, Data Stream, and could accomplish some missions like adding or deleting data over time, and completely avoiding accessing hard disks to achieve instant access, instant response and instant update. To meet the demands of this new area, Fully Skyline Computation on Data Streams, we create three algorithms for it. The experimental results showed that: as expected, the three algorithms can meet these demands, and the difference only lay in the amount of time-consuming. The process of designing these algorithms focused on the efficiency of different mechanisms or different views. Finally, Algorithm 3''s performance is better and how to effectively reduce the number of comparisons is the key.
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Shu, Yi-Teng, and 蘇易騰. "A Study on Parallel Skyline Query." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/15360212640147314161.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
100
The skyline query is an efficient data analysis tool for multi-criteria decision making that has received significant attention in the database community. With the advent of multi-core processors, we present a new parallel skyline query algorithm PSQ that can be applied to shared memory architectures, to progressively return skyline points as they are identified. The PSQ algorithm sorts the given dataset in descending order for coordinate component separately, and then finds out a terminating point for eliminating redundant computations of skyline query. Experimental results show that the PSQ algorithm successfully uses multiple cores to improve performance when dimensionality of the dataset grows or number of data points is large.
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KUO, PAO-SIAN, and 郭寶仙. "Applying Skyline Query to Sensor Network." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/82315821922387167830.
Full textAbstract:
碩士高苑科技大學
資訊科技應用研究所
102
With the fast advance of positioning techniques, spatio-temporal databases aiming at managing moving objects so as to provide useful information has attracted a lot attention. In real world, there are many applications related to spatio-temporal queries, such as geographic information, traffic monitoring system, and mobile information system. Skyline query is an important type of spatio-temporal queries. In this thesis, we focus on how to apply the skyline query to sensor network environment. Different form the previous research, in the sensor network environment, the positioning technique used is not the GPS technique, but is the sensor network technique. This results in a greater positioning error. In this thesis, we will try to manage the moving objects with uncertain location information. With the location information, we will design query algorithm to process the skyline queries. Benefiting from the developed query system, we can efficiently manage the moving objects and thus provide useful information to the user.
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Kuan-YingChiu and 邱冠穎. "Efficient Computation of Multiple Reverse Skyline Queries." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/84303454806804219176.
Full textAbstract:
碩士國立成功大學
資訊工程學系碩博士班
98
The related issues of skyline query have become more popular in the past few years. Recently, many researchers have focused on the reverse skyline query because it is very useful in many applications, such as environment monitoring and commercial decision. In most applications of reverse skyline query, users consider several query points at the same time. The na?ve method for processing multiple query points is to deal with each query point one by one. Unfortunately, this method incurs significant cost for processing query. In this paper, we propose an efficient processing algorithm, named Concurrent Reverse Skyline algorithm (CRS), for reverse skyline query with multiple points. It takes into account the relationships not only between query points but also between query point and data. And a batch processing technique is used to lower the processing cost. Thus the CRS could reduce the average processing cost of each query point. The experiment results also show the efficiency and effectively of our proposed algorithm under various environments.
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Cho, Kae-Jer, and 卓楷哲. "KSTR: Keyword-aware Skyline Travel Route Recommendation." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/07304812914186011929.
Full textAbstract:
碩士國立交通大學
資訊科學與工程研究所
104
With the popularity of social media (e.g., Facebook and Flickr), users could easily share their check-in records and photos during their trips. In view of the huge amount of check- in data and photos in social media, we intend to discover travel experiences to facilitate trip planning. Prior works have been elaborated on mining and ranking existing travel routes from check-in data. We observe that when planning a trip, users may have some keywords about preference on his/her trips. Moreover, a diverse set of travel routes is needed. To provide a diverse set of travel routes, we claim that more features of Places of Interests (POIs) should be extracted. Therefore, in this paper, we propose a Keyword-aware Skyline Travel Route (KSTR) framework that use knowledge extraction from historical mobility records and the user’s social interactions. Explicitly, we model the “Where, When, Who” issues by featurizing the geographical mobility pattern, temporal influence and social influence. Then we propose a keyword extraction module to classify the POI-related tags automatically into different types, for effective matching with query keywords. We further design a route reconstruction algorithm to construct route candidates that fulfill the query inputs. To provide diverse query results, we explore Skyline concepts to rank routes. To evaluate the effectiveness and efficiency of the proposed algorithms, we have conducted extensive experiments on real location-based social network datasets, and the experimental results show that KSTR does indeed demonstrate good performance compared to state-of-the-art works.
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Chen, Yu-Jie, and 陳裕傑. "Finding k-dominant Skyline with Partition Power." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/nv3mrt.
Full textAbstract:
碩士國立中興大學
資訊科學與工程學系
106
Skyline queries are widely used in many applications, such as decision analysis systems, multi-criteria decision-making, data mining, and user preferences. However, as the number of dimensions of data increases, the size of skyline query results will also increase dramatically. In addition, not every dimension is important or interesting to the user. Therefore, the skyline query results may contain many undesired data. Past research proposed the concept of k-dominant skyline to solve this problem and to reduce the size of skyline query results by relaxing the dominant conditions. This study proposes a method to rank data using the partition power index for high-dimensional datasets, and the proposed method can calculate the k-dominant skyline more efficiently. Ordering the data in the input datasets through the partition power index not only can efficiently calculate the k-dominant skyline, but also can filter the input dataset without affecting the quality of query results. Simulation experiments on both synthetic datasets and real datasets have verified that the proposed method can effectively calculate the k-dominant skyline.
42
Womack, Kevin C. "The dynamic behavior of a cable logging skyline and its effects on the tailspar /." 1989. http://hdl.handle.net/1957/9879.
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"Efficient Processing of Skyline Queries on Static Data Sources, Data Streams and Incomplete Datasets." Doctoral diss., 2014. http://hdl.handle.net/2286/R.I.27470.
Full textAbstract:
abstract: Skyline queries extract interesting points that are non-dominated and help paint the bigger picture of the data in question. They are valuable in many multi-criteria decision applications and are becoming a staple of decision support systems.
An assumption commonly made by many skyline algorithms is that a skyline query is applied to a single static data source or data stream. Unfortunately, this assumption does not hold in many applications in which a skyline query may involve attributes belonging to multiple data sources and requires a join operation to be performed before the skyline can be produced. Recently, various skyline-join algorithms have been proposed to address this problem in the context of static data sources. However, these algorithms suffer from several drawbacks: they often need to scan the data sources exhaustively to obtain the skyline-join results; moreover, the pruning techniques employed to eliminate tuples are largely based on expensive tuple-to-tuple comparisons. On the other hand, most data stream techniques focus on single stream skyline queries, thus rendering them unsuitable for skyline-join queries.
Another assumption typically made by most of the earlier skyline algorithms is that the data is complete and all skyline attribute values are available. Due to this constraint, these algorithms cannot be applied to incomplete data sources in which some of the attribute values are missing and are represented by NULL values. There exists a definition of dominance for incomplete data, but this leads to undesirable consequences such as non-transitive and cyclic dominance relations both of which are detrimental to skyline processing.
Based on the aforementioned observations, the main goal of the research described in this dissertation is the design and development of a framework of skyline operators that effectively handles three distinct types of skyline queries: 1) skyline-join queries on static data sources, 2) skyline-window-join queries over data streams, and 3) strata-skyline queries on incomplete datasets. This dissertation presents the unique challenges posed by these skyline queries and addresses the shortcomings of current skyline techniques by proposing efficient methods to tackle the added overhead in processing skyline queries on static data sources, data streams, and incomplete datasets.Dissertation/Thesis
Doctoral Dissertation Computer Science 2014
44
Rost, Steffen Thomas [Verfasser]. "Skyline query processing / vorgelegt von Steffen Thomas Rost." 2006. http://d-nb.info/981939821/34.
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Chang, Yu-Tu, and 張玉圖. "An Efficient Skyline Query Algorithm for Path Group." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/j4qngb.
Full textAbstract:
碩士逢甲大學
資訊工程學系
104
In recent years the skyline path query has been used very effectively in many business areas like logistics and transportation. A path group consists of a set of paths which cover all user interesting nodes. It’s useful for planning logistic routes or individual case visiting paths for social workers . Given a starting node s, a set of k interesting nodes and the cardinality of path group c, the skyline path group query retrieves a set of non-dominated path groups from a road network, where each edge has multi-dimension costs. Each path group includes all interesting nodes and meets the constraint of path group cardinality. Computing the skyline path group query is quite complex due to the extensive dominance test with path group tuples. This paper proposes an efficient approach for computing skyline path groups. The core of our method is pruning those path group sets that can’t become outstanding tuples while generating path groups. As shown in our experimental evaluation, we narrow down the search space and improve process time.
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Lin, Yi-Ying, and 林依潁. "Efficient Skyline Query Processing in Distributed Sensor Networks." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/68915284346263561968.
Full textAbstract:
碩士國立成功大學
資訊工程學系碩博士班
96
In recent years, the skyline operator has received considerable attention in the database research community. This is mainly due to the importance of various skyline results in applications involving multi-criteria decision making. On recently, skyline queries are considered in distributed computing environments (e.g., P2P networks, mobile ad hoc networks, and sensor networks). In this paper, we exploit the problem of skyline query processing in sensor networks. Many previous studies investigated efficient approaches to answer skyline queries in a centralized manner. However, those approaches cannot be applied directly to the sensor network environment primarily due to limited power and resource of sensor nodes. We proposed a skyline query processing mechanism, SKYSENSOR, that can efficiently retrieve skyline results from a distributed sensor network. Our solution is based on two main ideas: (1) the clustering architecture and (2) the pruning strategy. The clustering architecture partitions sensor readings into several clusters. By using the clustering architecture, we can identify the sensor that stores skyline points that dominate many data points in the early stage of the query processing. Those skyline points can be used to discard unqualified data points from further examination. The pruning strategy can help to control the amount of query forwarding, limiting the number of sensors involved and the amount of messages transmitted in the network. We conduct a comprehensive data set of experiments to reveal that SKYSENSOR significantly outperforms other existing methods while processing skyline query in a sensor network.
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Jin-Li, Lee, and 李俊利. "A Quantitative study of Skyline in Urban Design." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/71769640079564407142.
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Lin, Hsiou-Hao, and 林修豪. "Updating Skyline Efficiently by Using Z-order Mechanism." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/00402942888181154651.
Full textAbstract:
碩士國立東華大學
資訊工程學系
101
Skyline query is often adopted by user in the preference query. Generally, the data changes with time. Because partial data was updated with time, we need to maintain the correct skyline. Two simple ways to cope with the data updated situation are deleting the updated data first and then inserting the object as a new one or inserting the updated object first and then deleting the old one. However data deletion breaks the dominance relationship, and generates a lot of temporary skyline points. Moreover, if data updated is treated as data deletion/insertion, we need to perform dominance test to all database twice which is inefficient to maintain skyline in the data partial updated situation. In this thesis, by considering the dominance relationship between the data before updated and after updated, an efficient method for maintaining skyline is proposed. In addition, the transitivity of dominance property is applied. Moreover, a set of simulation is performed to show the benefit of the approach.
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kuan-chieh, Huang, and 黃冠捷. "A study for multiple constrained skyline queries processing." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/66953880343640440938.
Full textAbstract:
碩士長榮大學
資訊管理學系(所)
102
In this paper, we propose a constrained skyline query processing algorithms. This algorithm is named GCSQP. Compare with preview methods, GCSQP will merge and process them afterward . The advantage is that after the merger operation, GCSQP can save a lot of time to perform dominance test operation, thereby accelerating query processing efficiently. In this paper, we propose a GCSQP design concept, explain the details of the algorithm, and perform multiple experiments to prove that GCSQP can indeed accelerate query processing efficiently on constrained skyline query.
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Pin-ChiehHuang and 黃品介. "Finding Skyline with Customer Preferences and Cost Constraints." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/90894014984664598948.
Full textAbstract:
碩士國立成功大學
資訊工程學系
102
The importance of skyline and dominance relationship analysis has been well recognized in multicriteria decision-making applications. In this paper, we propose the problem of “Finding Skyline with Customer Preferences and Cost Constraints”, which utilizes the concept of dominance for business analysis from a microeconomic perspective. Our problem aims to discover the dominance relationship between products and potential customers. Given a set of customer preferences, we want to help the company to design set of competitive products so that the products can satisfy as many customer requirements as possible and the cost of producing the products is within a specified threshold. By “competitive products” we mean that the products cannot be dominated by other products in the market. We formally define the problem and discuss the difficulty of the problem. We also present the foundation and the intuition of our pruning methods. Then we proposed three efficient algorithms that utilize our pruning methods to address the problem. In addition, we also prove the correctness of our proposed algorithms. Finally, we conduct a thorough experimental evaluation that demonstrates the efficiency of our proposed algorithms.