K-coverage in regular deterministic sensor deployments

An area is k-covered if every point of the area is covered by at least k sensors. K-coverage is necessary for many applications, such as intrusion detection, data gathering, and object tracking. It is also desirable in situations where a stronger environmental monitoring capability is desired, such as military applications. In this paper, we study the problem of k-coverage in deterministic homogeneous deployments of sensors. We examine the three regular sensor deployments - triangular, square and hexagonal deployments - for k-coverage of the deployment area, for k ≥ 1. We compare the three regular deployments in terms of sensor density. For each deployment, we compute an upper bound and a lower bound on the optimal distance of sensors from each other that ensure k-coverage of the area. We present the results for each k from 1 to 20 and show that the required number of sensors to k-cover the area using uniform random deployment is approximately 3-10 times higher than regular deployments

Real-time Gesture Recognition Using RFID Technology

This paper presents a real-time gesture recognition technique based on RFID technology. Inexpensive and unintrusive passive RFID tags can be easily attached to or interweaved into user clothes. The tag readings in an RFID-enabled environment can then be used to recognize the user gestures in order to enable intuitive human-computer interaction. People can interact with large public displays without the need to carry a dedicated device, which can improve interactive advertisement in public places. In this paper, multiple hypotheses tracking is used to track the motion patterns of passive RFID tags. Despite the reading uncertainties inherent in passive RFID technology, the experiments show that the presented online gesture recognition technique has an accuracy of up to 96%

BROWSING LARGE ONLINE DATA USING GENERALIZED QUERY PREVIEWS

Companies, government agencies, and other organizations are making their data available to the world over the Internet. These organizations store their data in large tables. These tables are usually kept in relational databases. Online access to such databases is common. Users query these databases with different front-ends. These front-ends use command languages, menus, or form fillin interfaces. Many of these interfaces rarely give users information about the contents and distribution of the data. This leads users to waste time and network resources posing queries that have zero-hit or mega-hit results. Generalized query previews forms a user interface architecture for efficient browsing of large online data. Generalized query previews supplies distribution information to the users. This provides an overview of the data. Generalized query previews gives continuous feedback about the size of the results as the query is being formed. This provides a preview of the results. Generalized query previews allows users to visually browse all of the attributes of the data. Users can select from these attributes to form a view. Views are used to display the distribution information. Queries are incrementally and visually formed by selecting items from numerous charts attached to these views. Users continuously get feedback on the distribution information while they make their selections. Later, users fetch the desired portions of the data by sending their queries over the network. As they make informed queries, they can avoid submitting queries that will generate zero-hit or mega-hit results. Generalized query previews works on distributions. Distribution information tends to be smaller than raw data. This aspect of generalized query previews also contributes to better network performance. This dissertation presents the development of generalized query previews, field studies on various platforms, and experimental results. It also presents an architecture of the algorithms and data structures for the generalized query previews. There are three contributions of this dissertation. First, this work offers a general user interface architecture for browsing large online data. Second, it presents field studies and experimental work that define the application domain for generalized query previews. Third, it contributes to the field of algorithms and data structures. (UMIACS-TR-2001-70) (HCIL-TR-2001-22

Comparison of image space subdivision algorithms for parallel volume rendering

Ankara : Department of Computer Engineering and Information Science and Institute of Engineering and Science, Bilkent Univ., 1995.Thesis (Master's) -- Bilkent University, 1995.Includes bibliographical refences.In many scientific applications, results are presented as unstructured volumetric data sets. Direct Volume Rendering (DVR) is a powerful way of visualizing these volumetric data sets. However, it involves intensive computations. In addition, most of the volumetric data sets also require huge memories. Hence, DVR is a good candidate for parallelization on distributed memory multicomputers. Also most of the engineering simulations are done on multicomputers. Therefore, visualization of these results on the same architectures where simulations are done avoids the overhead of transporting large amount of data. In order to visualize unstructured volumetric data sets, the underlying algorithms should resolve the point location and the view sort problems of the 3D grid points. In this thesis, these problems are solved by using the well-known Scanline Z-Buffer algorithm. Three image space subdivision algorithms, namely horizontal, rectangular, and recursive subdivisions, are utilized to distribute the computations evenly among the processors in the rendering phase. The main parallel algorithm uses Raycasting approach of DVR to visualize the data sets, which is also an image space method. Therefore, the divisions are made in order to obtain a set of sub-images. Static task decomposition is used where each processor is assigned to a single sub-image. The load balance among the processors is achieved by defining the overall work load with in a sub-image by using the milestone operations done in the Scanline Z-Buffer algorithm. The algorithms are developed in a way that they can handle any kind of polygonal, volumetric, and etc. data set where the underlying architecture is also kept flexible in many aspects for the sake of generality and portability. The experimental performance evaluation of the horizontal, rectangular, and recursive subdivision algorithms on an IBM-SP2 system are presented and discussed in a comparative way.Tanin, EgemenM.S

On Optimal Arrangements of Binary Sensors

A large range of monitoring applications can benefit from binary sensor networks. Binary sensors can detect the presence or absence of a particular target in their sensing regions. They can be used to partition a monitored area and provide localization functionality. If many of these sensors are deployed to monitor an area, the area is partitioned into sub-regions: each sub-region is characterized by the sensors detecting targets within it. We aim to maximize the number of unique, distinguishable sub-regions. Our goal is an optimal placement of both omni-directional and directional static binary sensors. We compute an upper bound on the number of unique sub-regions, which grows quadratically with respect to the number of sensors. In particular, we propose arrangements of sensors within a monitored area whose number of unique sub-regions is asymptotically equivalent to the upper bound

Browsing Large Online Data Tables Using Generalized Query Previews (2001)

Companies, government agencies, and other organizations are making their data available to the world over the Internet. They often use large online relational tables for this purpose. Users query such tables with front-ends that typically use menus or form fillin interfaces, but these interfaces rarely give users information about the contents and distribution of the data. Such a situation leads users to waste time and network resources posing queries that have zero-hit or mega-hit results. Generalized query previews enable efficient browsing of large online databases by supplying data distribution information to the users. The data distribution information provides continuous feedback about the size of the result set as the query is being formed. Our paper presents a user interface architecture and discusses recent experimental findings. Our prototype system, ExpO, provides a flexible user interface for research and testing. The user study shows that for exploratory querying tasks, generalized query previews speed user performance and reduce network load

Real-time Gesture Recognition Using RFID Technology

This paper presents a real-time gesture recognition technique based on RFID technology. Inexpensive and unintrusive passive RFID tags can be easily attached to or interweaved into user clothes. The tag readings in an RFID-enabled environment can then be used to recognize the user gestures in order to enable intuitive human-computer interaction. People can interact with large public displays without the need to carry a dedicated device, which can improve interactive advertisement in public places. In this paper, multiple hypotheses tracking is used to track the motion patterns of passive RFID tags. Despite the reading uncertainties inherent in passive RFID technology, the experiments show that the presented online gesture recognition technique has an accuracy of up to 96%

Traffic Congestion Aware Route Assignment

Traffic congestion emerges when traffic load exceeds the available capacity of roads. It is challenging to prevent traffic congestion in current transportation systems where vehicles tend to follow the shortest/fastest path to their destinations without considering the potential congestions caused by the concentration of vehicles. With connected autonomous vehicles, the new generation of traffic management systems can optimize traffic by coordinating the routes of all vehicles. As the connected autonomous vehicles can adhere to the routes assigned to them, the traffic management system can predict the change of traffic flow with a high level of accuracy. Based on the accurate traffic prediction and traffic congestion models, routes can be allocated in such a way that helps mitigating traffic congestions effectively. In this regard, we propose a new route assignment algorithm for the era of connected autonomous vehicles. Results show that our algorithm outperforms several baseline methods for traffic congestion mitigation

Broadening Access to Large Online Databases by Generalizing Query Previews (2000)

Companies, government agencies, and other types of organizations are making their large databases available to the world over the Internet. Current database front-ends do not give users information about the distribution of data. This leads many users to waste time and network resources posing queries that have either zero-hit or mega-hit result sets. Query previews form a novel visual approach for browsing large databases. Query previews supply data distribution information about the database that is being searched and give continuous feedback about the size of the result set for the query as it is being formed. On the other hand, query previews use only a few pre-selected attributes of the database. The distribution information is displayed only on these attributes. Unfortunately, many databases are formed of numerous relations and attributes. This paper introduces a generalization of query previews. We allow users to browse all of the relations and attributes of a database using a hierarchical browser. Any of the attributes can be used to display the distribution information, making query previews applicable to many public online databases