1,720,961 research outputs found
Efficient Processing of Proximity-Aware Spatial Queries in Road Networks
No full text학위논문(박사)--아주대학교 일반대학원 :컴퓨터공학과,2017. 8CHAPTER 1. Introduction 1
1.1 Motivation 1
1.2 Contributions 3
1.3 Thesis Outline 5
CHAPTER 2. Background 6
2.1 Spatial Databases 6
2.1.1 Modeling 6
2.2 Proximity-Aware Spatial Queries 9
2.3 Related Work 12
2.3.1 Reverse Nearest Neighbor Queries 13
2.3.2 Top-k Spatial Preference Queries 16
2.3.3 Top-k Spatial Keyword Queries 19
CHAPTER 3. Various Proximity-Aware Spatial Queries in Road Networks 21
3.1 Processing Reverse k Nearest Neigbhor Queries 21
3.1.1 Overview 21
3.1.2 Preliminaries 25
3.1.3 Safe Exit Algorithm for Moving RkNN Queries and Moving Objects 29
3.1.4 RkNN Queries in Dynamic Road Networks 49
3.2 Top-k Spatial Preference Queries in Directed Road Networks 52
3.2.1 Overview 52
3.2.2 Preliminaries 54
3.2.3 Pruning and Grouping 58
3.2.4 Top-k Spatial Prefernce Query Algorithm 73
3.3 Top-k Spatial Keyword Queries in Directed Road Networks 82
3.3.1 Overview 82
3.3.2 Preliminaries 84
3.3.3 Query Processing System 86
CHAPTER 4. Performance Evaluation 91
4.1 Performance Evaluation of CORE-X 91
4.1.1 Experimental Settings 91
4.1.2 Experimental Results for Static Road Networks 93
4.1.3 Experimental Results for Dynamic Road Networks 97
4.2 Performance Evaluation of TOPS 101
4.2.1 Experimental Settings 102
4.2.2 Experimental Results for Query Processing Time 103
4.2.3 Experimental Results for Materialization and Incremental Maintenance Costs 108
4.3 Performance Evaluation of eSPAK 111
4.3.1 Experimental Settings 111
4.3.2 Experimental Results 113
CHAPTER 5. Conclusion 117
References 119
Publications List 127DoctoralWith the explosive growth in spatial information and emergence of new technologies, a number of applications such as GIS, VLSI and decision support systems are exploiting the location dimension to provide services. Moreover, the rapid technological advances in wireless networks and development of smartphones have popularized location-based services. Majority of these applications uses proximity-aware spatial queries to provide services. A proximity-aware spatial queries computes the results based on the closeness of objects. Reverse k nearest neighbor queries (RkNN), top-k spatial preference queries and top-k spatial keyword queries are some of the important proximity-aware spatial queries. In this thesis, we provide efficient techniques for processing these queries in road networks.
In this thesis, we present efficient techniques to continuously monitor RkNN queries where both query and data objects are moving. The main challenge in continuous RkNN queries is to maintain the freshness of query results because results may nullify due to movement of query or data objects. We propose a safe exit-based algorithm called CORE-X for efficiently computing the safe exit points of both query and data objects. Within the safe region, the query result remains unchanged provided that query and data objects remains inside their respective safe regions. Furthermore, we also provide efficient solution for processing RkNN queries in dynamic road networks where the network distance changes depending on the traffic conditions.
Top-k preference queries are crucial for a wide range of location based services such as hotel browsing and apartment searching. In recent years, a lot of research has been conducted on processing of top-k spatial preference queries in Euclidean space. While few algorithms study top-k preference queries in road networks, they all focus on undirected road networks. To the best of our knowledge, we are the first to investigate the problem of processing the top-k spatial preference queries in directed road networks where each road segment has a particular orientation. To the best of our knowledge, this is the first study to address this problem. We propose a pruning and grouping of feature objects to reduce the number of feature objects which improve the query processing time. Additionally, we present an efficient algorithm called TOPS that can process top-k spatial preference queries in directed road networks.
Top-k keyword queries can be used for a wide range of applications in recommendation systems and decision support systems. Several solutions have been proposed for top-k spatial keyword queries in Euclidean space. However, few algorithms study top-k keyword queries in undirected road networks where every road segment is undirected. Even worse, insufficient attention has been given to the processing of keyword queries in directed road networks where each road segment has a particular orientation. In this study, we are the first to address this issue and proposed efficient techniques for processing top-k spatial keyword queries in directed road networks.
All the approaches we propose have been validated through extensive experimental evaluation on real road networks. The results we obtained show that our proposed techniques significantly improves the performance of these proximity-aware spatial queries in road networks
Smart Healthcare Using Data-Driven Prediction of Immunization Defaulters in Expanded Program on Immunization (EPI)
Full text linkImmunization is a noteworthy and proven tool for eliminating life-threating infectious diseases, child mortality and morbidity. Expanded Program on Immunization (EPI) is a nation-wide program in Pakistan to implement immunization activities, however the coverage is quite low despite the accessibility of free vaccination. This study proposes a defaulter prediction model for accurate identification of defaulters. Our proposed framework classifies defaulters at five different stages: defaulter, partially high, partially medium, partially low, and unvaccinated to reinforce targeted interventions by accurately predicting children at high risk of defaulting from the immunization schedule. Different machine learning algorithms are applied on Pakistan Demographic and Health Survey (2017-18) dataset. Multilayer Perceptron yielded 98.5% accuracy for correctly identifying children who are likely to default from immunization series at different risk stages of being defaulter. In this paper, the proposed defaulters' prediction framework is a step forward towards a data-driven approach and provides a set of machine learning techniques to take advantage of predictive analytics. Hence, predictive analytics can reinforce immunization programs by expediting targeted action to reduce dropouts. Specially, the accurate predictions support targeted messages sent to at-risk parents' and caretakers' consumer devices (e.g., smartphones) to maximize healthcare outcomes
Offline signature verification system: a novel technique of fusion of GLCM and geometric features using SVM
No full textIn the area of digital biometric systems, the handwritten signature plays a key role in the authentication of a person based on their original samples. In offline signature verification (OSV), several problems exist that are challenging for verification of authentic or forgery signature by the digital system. Correct signature verification improves the security of people, systems, and services. It is applied to uniquely identify an individual based on the motion of pen as up and down, signature speed, and shape of a loop. In this work, the multi-level features fusion and optimal features selection based automatic technique is proposed for OSV. For this purpose, twenty-two Gray Level Co-occurrences Matrix (GLCM) and eight geometric features are calculated from pre-processing signature samples. These features are fused by a new parallel approach which is based on a high-priority index feature (HPFI). A skewness-kurtosis based features selection approach is also proposed name skewness-kurtosis controlled PCA (SKcPCA) and selects the optimal features for final classification into forged and genuine signatures. MCYT, GPDS synthetic, and CEDAR datasets are utilized for validation of the proposed system and show enhancement in terms of Far and FRR as compared to existing methods
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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