Social and Behavioral Sciences Commons^™

Spatial Queries In The Presence Of Obstacles, Jun Zhang, Dimitris Papadias, Kyriakos Mouratidis, Manli Zhu

Kyriakos MOURATIDIS

Despite the existence of obstacles in many database applications, traditional spatial query processing utilizes the Euclidean distance metric assuming that points in space are directly reachable. In this paper, we study spatial queries in the presence of obstacles, where the obstructed distance between two points is defined as the length of the shortest path that connects them without crossing any obstacles. We propose efficient algorithms for the most important query types, namely, range search, nearest neighbors, e-distance joins and closest pairs, considering that both data objects and obstacles are indexed by R-trees. The effectiveness of the proposed solutions is verified …

Continuous Medoid Queries Over Moving Objects, Stavros Papadopoulos, Dimitris Sacharidis, Kyriakos Mouratidis

Kyriakos MOURATIDIS

In the k-medoid problem, given a dataset P, we are asked to choose kpoints in P as the medoids. The optimal medoid set minimizes the average Euclidean distance between the points in P and their closest medoid. Finding the optimal k medoids is NP hard, and existing algorithms aim at approximate answers, i.e., they compute medoids that achieve a small, yet not minimal, average distance. Similarly in this paper, we also aim at approximate solutions. We consider, however, the continuous version of the problem, where the points in P move and our task is to maintain the medoid set on-the-fly …

Spatial Cloaking Revisited: Distinguishing Information Leakage From Anonymity, Kar Way Tan, Yimin Lin, Kyriakos Mouratidis

Kyriakos MOURATIDIS

Location-based services (LBS) are receiving increasing popularity as they provide convenience to mobile users with on-demand information. The use of these services, however, poses privacy issues as the user locations and queries are exposed to untrusted LBSs. Spatial cloaking techniques provide privacy in the form of k-anonymity; i.e., they guarantee that the (location of the) querying user u is indistinguishable from at least k-1 others, where k is a parameter specified by u at query time. To achieve this, they form a group of k users, including u, and forward their minimum bounding rectangle (termed anonymzing spatial region, ASR) to …

Medoid Queries In Large Spatial Databases, Kyriakos Mouratidis, Dimitris Papadias, Spiros Papadimitriou

Kyriakos MOURATIDIS

Assume that a franchise plans to open k branches in a city, so that the average distance from each residential block to the closest branch is minimized. This is an instance of the k-medoids problem, where residential blocks constitute the input dataset and the k branch locations correspond to the medoids. Since the problem is NP-hard, research has focused on approximate solutions. Despite an avalanche of methods for small and moderate size datasets, currently there exists no technique applicable to very large databases. In this paper, we provide efficient algorithms that utilize an existing data-partition index to achieve low CPU …

Management Of Land Use Land Cover Through The Application Of Remote Sensing, Geographic Information Systems And Simulation, Praveen Jha

Praveen Jha Dr

Deforestation and degradation of forest areas, including those in the Protected Areas (PAs), are major concerns in India. There were 2 broad objectives of the study: the technological objective pertained to the development of state-of-art programs that could serve as Decision Support Systems while finalizing plans and policy interventions, while the other objective aimed at generating geo-spatial data in 2 PAs. A part of the Eastern Himalaya biodiversity hotspot, Manas Tiger Reserve (MTR), Assam, India having an area of 2837.12 sq km and an important part of Rajaji-Corbett Tiger Conservation Unit, Rajaji National Park (RNP), Uttarakhand, India, having an area …

Popular People Help Experts Predict Flu Outbreak?, Chiehwen Ed Hsu

Chiehwen Ed Hsu

Popular people are the trendsetters of society, especially when it comes to the next flu outbreak, according to preliminary research from Harvard University. The hypochondriac effect may have also exaggerated how predictive the friend group was, says Ed Hsu, associate professor of Public Health Informatics at the University of Texas. Those in the friend group are more likely to know someone who has the flu and hence may be more likely to think (and report) that they are coming down with it themselves.

A Framework For Computational Thinking Across The Curriculum, Ljubomir Perkovi´C, Amber Settle, Sungsoon Hwang, Joshua Jones

Sungsoon Hwang

We describe a framework for implementing computational thinking in a broad variety of general education courses. The framework is designed to be used by faculty without formal training in information technology in order to understand and integrate computational thinking into their own general education courses. The framework includes examples of computational thinking in a variety of general education courses, as well as sample in-class activities, assignments, and other assessments for the courses. The examples in the different courses are related and differentiated using categories taken from Denning Great Principles of Computing, so that similar types of computational thinking appearing in …

Influence Of Job Accessibility On Housing Market Processes: Study Of Spatial Stationarity In The Buffalo And Seattle Metropolitan Areas, Sungsoon Hwang, Jean-Claude Thill

Sungsoon Hwang

Towards Voluntary Interoperable Open Access Licenses For The Global Earth Observation System Of Systems (Geoss), Harlan Onsrud, James Campbell, Bastiaan Van Loenen

Harlan J Onsrud

Access to earth observation data has become critically important for the wellbeing of society. A major impediment to achieving widespread sharing of earth observation data is lack of an operational web-wide system that is transparent and consistent in allowing users to legally access and use the earth observations of others without seeking permission from data contributors or investigating terms of usage on a case-by-case basis. This article explores approaches to supplying a license-based system to overcome this impediment in the context of the Global Earth Observation System of Systems. It discusses the benefits and drawbacks of the explored approaches and …

Terminal Archaic Settlement Pattern And Land Cover Change In The Rio Ilave, Southwestern Lake Titicaca Basin, Perú, Nathan M. Craig, Mark Aldenderfer, Paul Baker, Catherine Rigsby

Nathan M Craig

Researchers have argued the modern Altiplano land cover—one of bunch grasses and few indigenous tree species—is an anthropogenic artifact of land use practices initiated after the arrival of Europeans in the sixteenth century a.d. Recent paleoenvironmental studies of the Lake Titicaca Basin challenge this assertion. Archaeological survey and excavation data from the Rio Ilave drainage indicate that settlement aggregation and reduced residen¬tial mobility began in the Late Archaic Period about 3000 cal b.c. Terminal Archaic occupational intensity increased after 2000 cal b.c. and continued up until about 1300 cal b.c., which marks the beginning of the Formative in the basin. …

Wind Energy Deployment: Global Lessons For West Michigan, Erik Edward Nordman

Erik Edward Nordman

West Michigan Wind Assessment Issue Brief #1 This first of series of issue briefs summarizes the factors that have influenced wind energy deployment across the country and around the world. It also brings the lessons home to West Michigan's coastal zone.

Wind Power And Human Health: Flicker, Noise And Air Quality, Erik Edward Nordman

Erik Edward Nordman

West Michigan Wind Assessment Issue Brief #2 The second of a series of wind energy issue briefs synthesizes the state of the science around wind energy siting issues like flicker and noise, and analyzes how West Michigan communities are addressing these challenges. The issue brief also assesses how wind energy could improve air quality and human health outcomes in West Michigan and the region.

Wind Energy Glossary: Technical Terms And Concepts, Erik Edward Nordman

Erik Edward Nordman

The terms in this glossary are organized into three sections: (1) Electricity Transmission Network; (2) Wind Turbine Components; and (3) Wind Energy Challenges, Issues and Solutions.