Physical Sciences and Mathematics Commons^™

Anonymous Query Processing In Road Networks, Kyriakos Mouratidis, Man Lung Yiu

Kyriakos MOURATIDIS

The increasing availability of location-aware mobile devices has given rise to a flurry of location-based services (LBSs). Due to the nature of spatial queries, an LBS needs the user position in order to process her requests. On the other hand, revealing exact user locations to a (potentially untrusted) LBS may pinpoint their identities and breach their privacy. To address this issue, spatial anonymity techniques obfuscate user locations, forwarding to the LBS a sufficiently large region instead. Existing methods explicitly target processing in the euclidean space and do not apply when proximity to the users is defined according to network distance …

On-Line Discovery Of Hot Motion Paths, Dimitris Sacharidis, Kostas Patroumpas, Manolis Terrovitis, Verena Kantere, Michalis Potamias, Kyriakos Mouratidis, Timos Sellis

Kyriakos MOURATIDIS

We consider an environment of numerous moving objects, equipped with location-sensing devices and capable of communicating with a central coordinator. In this setting, we investigate the problem of maintaining hot motion paths, i.e., routes frequently followed by multiple objects over the recent past. Motion paths approximate portions of objects' movement within a tolerance margin that depends on the uncertainty inherent in positional measurements. Discovery of hot motion paths is important to applications requiring classification/profiling based on monitored movement patterns, such as targeted advertising, resource allocation, etc. To achieve this goal, we delegate part of the path extraction process to objects, …

Continuous Monitoring Of Spatial Queries In Wireless Broadcast Environments, Kyriakos Mouratidis, Spiridon Bakiras, Dimitris Papadias

Kyriakos MOURATIDIS

Wireless data broadcast is a promising technique for information dissemination that leverages the computational capabilities of the mobile devices in order to enhance the scalability of the system. Under this environment, the data are continuously broadcast by the server, interleaved with some indexing information for query processing. Clients may then tune in the broadcast channel and process their queries locally without contacting the server. Previous work on spatial query processing for wireless broadcast systems has only considered snapshot queries over static data. In this paper, we propose an air indexing framework that 1) outperforms the existing (i.e., snapshot) techniques in …

Optimal Matching Between Spatial Datasets Under Capacity Constraints, Hou U Leong, Kyriakos Mouratidis, Man Lung Yiu, Nikos Mamoulis

Kyriakos MOURATIDIS

Consider a set of customers (e.g., WiFi receivers) and a set of service providers (e.g., wireless access points), where each provider has a capacity and the quality of service offered to its customers is anti-proportional to their distance. The capacity constrained assignment (CCA) is a matching between the two sets such that (i) each customer is assigned to at most one provider, (ii) every provider serves no more customers than its capacity, (iii) the maximum possible number of customers are served, and (iv) the sum of Euclidean distances within the assigned provider-customer pairs is minimized. Although max-flow algorithms are applicable …

Continuous Spatial Assignment Of Moving Users, Leong Hou U, Kyriakos Mouratidis, Nikos Mamoulis

Kyriakos MOURATIDIS

Consider a set of servers and a set of users, where each server has a coverage region (i.e., an area of service) and a capacity (i.e., a maximum number of users it can serve). Our task is to assign every user to one server subject to the coverage and capacity constraints. To offer the highest quality of service, we wish to minimize the average distance between users and their assigned server. This is an instance of a well-studied problem in operations research, termed optimal assignment. Even though there exist several solutions for the static case (where user locations are fixed), …

Shortest Path Computation On Air Indexes, Georgios Kellaris, Kyriakos Mouratidis

Kyriakos MOURATIDIS

Shortest path computation is one of the most common queries in location-based services that involve transportation net- works. Motivated by scalability challenges faced in the mo- bile network industry, we propose adopting the wireless broad- cast model for such location-dependent applications. In this model the data are continuously transmitted on the air, while clients listen to the broadcast and process their queries locally. Although spatial problems have been considered in this environment, there exists no study on shortest path queries in road networks. We develop the rst framework to compute shortest paths on the air, and demonstrate the practicality and …

Preference Queries In Large Multi-Cost Transportation Networks, Kyriakos Mouratidis, Yimin Lin, Man Lung Yiu

Kyriakos MOURATIDIS

Research on spatial network databases has so far considered that there is a single cost value associated with each road segment of the network. In most real-world situations, however, there may exist multiple cost types involved in transportation decision making. For example, the different costs of a road segment could be its Euclidean length, the driving time, the walking time, possible toll fee, etc. The relative significance of these cost types may vary from user to user. In this paper we consider such multi-cost transportation networks (MCN), where each edge (road segment) is associated with multiple cost values. We formulate …

Pre-Eruption Pressure, Temperature And Volatile Content Of Rhyolite Magma From The 1650 Ad Eruption Of Kolumbo Submarine Volcano, Greece, K. Cantner, S. Carey, H. Sigurdsson, G. Vougioukalakis, P. Nomikou, C. Roman, K. Bell, M. Alexandri

Christopher N. Roman

Biotite-bearing, crystal-poor rhyolite magma was the predominant magma type discharged during the 1650 AD explosive eruption of Kolumbo submarine volcano, Greece. The eruption produced thick sequences of pumice deposits (~100 m) in the upper crater walls of the volcano, but also led to the formation of extensive pumice rafts that were dispersed throughout the southern Aegean Sea, and subaerial tephra fallout as far east as Turkey. Preliminary estimates of pre-eruption volatile contents have been determined using the volatile-by-difference method on plagioclase-hosted melt inclusions and yield an average value of 6.0 wt.%. This corresponds to a pre-eruption storage pressure of 180 …

Adaptive Checkpointing For Master-Worker Style Parallelism (Extended Abstract), Gene D. Cooperman, Jason Ansel, Xiaoqin Ma

Gene D. Cooperman

No abstract provided.

Dmtcp: Transparent Checkpointing For Cluster Computations And The Desktop, Jason Ansel, Kapil Arya, Gene D. Cooperman

Gene D. Cooperman

DMTCP (Distributed MultiThreaded CheckPointing) is a transparent user-level checkpointing package for distributed applications. Checkpointing and restart is demonstrated for a wide range of over 20 well known applications, including MATLAB, Python, TightVNC, MPICH2, OpenMPI, and runCMS. RunCMS runs as a 680 MB image in memory that includes 540 dynamic libraries, and is used for the CMS experiment of the Large Hadron Collider at CERN. DMTCP transparently checkpoints general cluster computations consisting of many nodes, processes, and threads; as well as typical desktop applications. On 128 distributed cores (32 nodes), checkpoint and restart times are typically 2 seconds, with negligible run-time …

Closing The Gap Between The Industry And Higher Education Institutions- Case Examples From East African Region, Deogratias Harorimana Mr

Dr Deogratias Harorimana

Much complained about is the quality of graduates Universities put on the labour market. Less talked about however is why knowledge institutions seems to be bad knowledge managers. In this presentation I argue that DIRECT collaborative relationship between Industry,Governments and Higher Education Institutions is a per-requisite.Good relationship is key to building such a successful knowledge transfer strategies between Industries and Educational and Research Institutions. This paper explores what makes a good Knowledge Transfer Partnership Strategy and highlights some key lessons for businesses, Universities and Government bodies. This paper was a Key note presentation to the Annual International Conference on Building …

The Kerf Toolkit For Intrusion Analysis, Javed A. Aslam, Sergey Bratus, David Kotz, Ron Peterson, Brett Tofel, Daniela Rus

Javed A. Aslam

To aid system administrators with post-attack intrusion analysis, the Kerf toolkit provides an integrated front end and powerful correlation and data-representation tools, all in one package.

Demonstrating Contradictions In A Graphical User Interface, Umakant Mishra

Umakant Mishra

Designing a GUI is not so easy as it may appear to outside. The developer has to face many difficulties while improving the features of a GUI. In many cases improving one feature of a GUI results in worsening another feature of it, thus leading to a situation known as contradiction in TRIZ. Many such contradictions have been solved by different inventors in the past. We will demonstrate some important contradictions in this article and discuss alternative solutions for each contradiction.

Control System Performance And Efficiency For A Mid-Depth Lagrangian Profiling Float, B. Mcgilvray, C. Roman

Christopher N. Roman

This paper presents the development of a new mid-depth Lagrangian profiling float with a primary emphasis on the control system performance and efficiency. While deep water floats have demonstrated much success in open ocean environments, many are not suited for the additional challenges associated with coastal regions. To study these regions, which are often subject to varying bathymetry within the operating range and higher variations in water density, a more advanced system is required. This new design utilizes pressure and altitude feedback to drive a high volume auto-ballasting system (ABS). The main operating modes of this float include step inputs …

Constrained Stereo Correspondence For 3d Sea-Floor Reconstruction, Gabrielle Inglis, Chris Roman

Christopher N. Roman

No abstract provided.

Fast Energy Loss Computation And Fuzzy-Based Shunt Capacitor Insertion, Philadelphia University

Philadelphia University, Jordan

No abstract provided.

Rwanda National Customer Satisfaction Survey: Results And Conclusions, Deogratias Harorimana

Dr Deogratias Harorimana

It can be said that development practice requires more than financial and manpower inputs. Rwanda, in 1994 suffered a Genocide. The Society,collectively and under the leadership of His Excellence Paul Kagame the current elected President of Rwanda came together and designed strategies that would propel Rwanda to a Middle-Income, Private Sector Led Economy by the Year 2020.

In 2009, a client seating in one of the Hotels in a Suburb of Remera, in Kigali City, complained about poor service delivery he was experiencing from the waitress staff.Using his Blackberry message, the client forwarded an email to some of the RDB …

Enterprise Development Policies And Capacity-Building In Science, Technology And Innovation (Sti)-Response To The Issue Note, Deogratias Harorimana

Dr Deogratias Harorimana

Enterprise Development, Investment and Business Climate are all important for economic growth. But what policies, strategies are needed to make economic growth a reality. The author has followed one of the World's fastest reformer and emerging nation in the Heart of Africa-Rwanda. The paper shares lessons and practical aspects related to building an entrepreneurial population, and building a government which is a facilitator of business climate

Survey Report On Training And Spending On Customer Care Services, Deogratias Harorimana Sr

Dr Deogratias Harorimana

In a bid to promote and develop good customer care service in various sectors of Rwandan economy, a survey was conducted to assess progress and trends on customer service capacity building. Although shortcomings are there, there have been efforts and registered trends across the country on service delivery front. Investment in Capacity Building IS happening in certain sectors but this is unevenly distributed. In 2008 companies had started recognizing the significance of good service and cultivate a good working environment and training. From 2009, there was a decline in investment in capacity building in front office and key service delivery …

Mining Frequent Generalized Patterns For Web Personalization In The Presence Of Taxonomies, Panagiotis Giannikopoulos, Iraklis Varlamis, Magdalini Eirinaki

Magdalini Eirinaki

The Web is a continuously evolving environment, since its content is updated on a regular basis. As a result, the traditional usage-based approach to generate recommendations that takes as input the navigation paths recorded on the Web page level, is not as effective. Moreover, most of the content available online is either explicitly or implicitly characterized by a set of categories organized in a taxonomy, allowing the page-level navigation patterns to be generalized to a higher, aggregate level. In this direction, the authors present the Frequent Generalized Pattern (FGP) algorithm. FGP takes as input the transaction data and a hierarchy …

Embedded Systems As Datacenters, Robert Iannucci

Robert A Iannucci

No abstract provided.