Results 1 - 10 of 3,834

1A Fade Level-based Spatial Model for Radio Tomographic Imaging

by Ossi Kaltiokallio, Maurizio Bocca, Neal Patwari Member
"... Abstract—RSS-based device-free localization (DFL) monitors changes in the received signal strength (RSS) measured by a network of static wireless nodes to locate and track people without requiring them to carry or wear any electronic device. Current models assume that the spatial impact area, i.e., ..."
Abstract - Cited by 6 (5 self) - Add to MetaCart
.e., the area in which a person affects a link’s RSS, has constant size. This paper shows that the spatial impact area varies considerably for each link. Data from extensive experiments are used to derive a spatial weight model that is a function of the fade level, i.e., a measure of whether a link

Segmentation of brain MR images through a hidden Markov random field model and the expectation-maximization algorithm

by Yongyue Zhang, Michael Brady, Stephen Smith - IEEE TRANSACTIONS ON MEDICAL. IMAGING , 2001
"... The finite mixture (FM) model is the most commonly used model for statistical segmentation of brain magnetic resonance (MR) images because of its simple mathematical form and the piecewise constant nature of ideal brain MR images. However, being a histogram-based model, the FM has an intrinsic limi ..."
Abstract - Cited by 639 (15 self) - Add to MetaCart
limitation—no spatial information is taken into account. This causes the FM model to work only on well-defined images with low levels of noise; unfortunately, this is often not the the case due to artifacts such as partial volume effect and bias field distortion. Under these conditions, FM model-based

Three-dimensional object recognition from single two-dimensional images

by David G. Lowe - Artificial Intelligence , 1987
"... A computer vision system has been implemented that can recognize threedimensional objects from unknown viewpoints in single gray-scale images. Unlike most other approaches, the recognition is accomplished without any attempt to reconstruct depth information bottom-up from the visual input. Instead, ..."
Abstract - Cited by 484 (7 self) - Add to MetaCart
, a probabilistic ranking method is used to reduce the size of the search space during model based matching. Finally, a process of spatial correspondence brings the projections of three-dimensional models into direct correspondence with the image by solving for unknown viewpoint and model parameters

From theory to practice: an overview of MIMO space-time coded wireless systems

by David Gesbert, Mansoor Shafi, Da-shan Shiu, Peter J. Smith, Ayman Naguib - IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS , 2003
"... This paper presents an overview of recent progress in the area of multiple-input–multiple-output (MIMO) space–time coded wireless systems. After some background on the research leading to the discovery of the enormous potential of MIMO wireless links, we highlight the different classes of technique ..."
Abstract - Cited by 371 (6 self) - Add to MetaCart
of techniques and algorithms proposed which attempt to realize the various benefits of MIMO including spatial multiplexing and space–time coding schemes. These algorithms are often derived and analyzed under ideal independent fading conditions. We present the state of the art in channel modeling

Reactive Modules

by Rajeev Alur , Thomas A. Henzinger - FORMAL METHODS IN SYSTEM DESIGN , 1996
"... We present a formal model for concurrent systems. The model represents synchronous and asynchronous components in a uniform framework that supports compositional (assume-guarantee) and hierarchical (stepwise-refinement) design and verification. While synchronous models are based on a notion of at ..."
Abstract - Cited by 324 (38 self) - Add to MetaCart
We present a formal model for concurrent systems. The model represents synchronous and asynchronous components in a uniform framework that supports compositional (assume-guarantee) and hierarchical (stepwise-refinement) design and verification. While synchronous models are based on a notion

Local Reasoning about Programs that Alter Data Structures

by Peter O'Hearn, John Reynolds, Hongseok Yang , 2001
"... We describe an extension of Hoare's logic for reasoning about programs that alter data structures. We consider a low-level storage model based on a heap with associated lookup, update, allocation and deallocation operations, and unrestricted address arithmetic. The assertion language is ba ..."
Abstract - Cited by 324 (28 self) - Add to MetaCart
We describe an extension of Hoare's logic for reasoning about programs that alter data structures. We consider a low-level storage model based on a heap with associated lookup, update, allocation and deallocation operations, and unrestricted address arithmetic. The assertion language

On the capacity of spatially correlated MIMO Rayleigh-fading channels

by Marco Chiani, Senior Member, Moe Z. Win, Senior Member, Alberto Zanella - IEEE Trans. Inform. Theory , 2003
"... Abstract—In this paper, we investigate the capacity distribution of spatially correlated, multiple-input–multiple-output (MIMO) channels. In particular, we derive a concise closed-form expression for the characteristic function (c.f.) of MIMO system capacity with arbitrary correlation among the tran ..."
Abstract - Cited by 134 (15 self) - Add to MetaCart
Abstract—In this paper, we investigate the capacity distribution of spatially correlated, multiple-input–multiple-output (MIMO) channels. In particular, we derive a concise closed-form expression for the characteristic function (c.f.) of MIMO system capacity with arbitrary correlation among

Deconstructing multi-antenna fading channels

by Akbar M. Sayeed, Senior Member - IEEE Trans. Sig. Proc. (special issue on space-time coded transmission , 2002
"... Abstract—Accurate and tractable channel modeling is critical to realizing the full potential of antenna arrays in wireless communications. Current approaches represent two extremes: idealized statistical models representing a rich scattering environment and parameterized physical models that describ ..."
Abstract - Cited by 156 (32 self) - Add to MetaCart
an intermediate virtual channel representation that captures the essence of physical modeling and provides a simple geometric interpretation of the scattering environment. The virtual representation corresponds to a fixed coordinate transformation via spatial basis functions defined by fixed virtual angles. We

Social Vulnerability to Environmental Hazards

by Susan L. Cutter - Social Science Quarterly
"... For over 50 years, hazards researchers have focused on a series of fundamental ques-tions: 1) what is the human occupancy of hazard zones? 2) How do people and societies respond to environmental hazards and what factors influence their choice of adjust-ments? 3) How do you mitigate the risk and impa ..."
Abstract - Cited by 269 (4 self) - Add to MetaCart
and contradiction on the meaning of the term; measurement; and the causes of spatial outcomes associa-ted with vulnerability studies. A new conceptual model of vulnerability is then pro-posed, the hazards of place, which clarifies many of the discrepancies found in the existing literature.

Representations of Rigid Solids: Theory, Methods, and Systems

by Aristides A. G. Requicha - ACM Computing Surveys , 1980
"... Computer-based ystems for modehng the geometry ofrigid solid objects are becoming increasingly important inmechanical nd civil engineering, architecture, computer graphics, computer vision, and other fields that deal with spatial phenomena. At the heart of such systems are symbol structures (represe ..."
Abstract - Cited by 256 (2 self) - Add to MetaCart
Computer-based ystems for modehng the geometry ofrigid solid objects are becoming increasingly important inmechanical nd civil engineering, architecture, computer graphics, computer vision, and other fields that deal with spatial phenomena. At the heart of such systems are symbol structures
Results 1 - 10 of 3,834