Envelopes and clutters

AbstractIn this paper, a set function ϕ defined on a finite set Ω is said to be an upper envelope if there exists a set {pi} of nonnegative vectors on Ω such that ϕ(G)=max{p1(G),…,pn(G)} for all G⊂Ω. All upper envelopes form a convex cone. We give a necessary and sufficient condition for an upper envelope to be extremal in the cone of all upper envelopes in terms of its representation. Furthermore we study the upper envelopes represented by clutters. We show that a clutter is extremal in the cone of the upper envelopes if and only if it satisfies some kind of connectivity

1 1/2 Years in Death Valley

This paper is an exploration into the historian as an independent source of history. Homer T. Rosenberger was an amateur historian in Pennsylvania during the better part of the 20th century. His works on Pennsylvania history, early American history, and contemporary historical events are valuable, if unknown, resources in those fields. However, Rosenberger becomes his own source of history when his battle with cancer is examined in the context of the American 1950\u27s. Rosenberger\u27s reactions to his plight help illustrate the mindset American brought to cancer in the 1950\u27s and the transition in American society since then

Clutter analysis and simulation in forward scatter micro radar network

Over the past few years, numbers of research have been carried out to investigate the clutter characteristic especially for conventional monostatic and bistatic radar detection (mostly in maritime and airborne using Ultra Wide Band radar and Synthetic Aperture Radar) and not specifically on Forward Scatter Radar (FSR). FSR provides an efficient approach for detection of stealth target, the simplicity of the hardware design, increase the power budget and work in all weather operation. One of the limitations in forward scatter radar is the range resolution. Clutter mainly from the surrounding vegetation is picked up from a large area illuminated by transmitter and receiver which is located on the ground. Vegetation clutter is a significant factor that limits the performance of ground based Forward Scatter Radar. In this research, the analysis is focused on clutter on ground-based Forward Scatter Micro Radar system network where the clutter characteristics are studied for different environmental conditions such as different land sites, wind and weather conditions for different carrier frequencies. These comprehensive analyses are used eventually, to determine the clutter characteristics and are used for clutter modelling in order to create similar clutter-like signal that can be used to develop a synthetic environment for Forward Scatter Radar detection performance analysis in the future. Three main works have been done; 1) real measurements to determine the Clutter characteristic for FSR based on statistical analysis of a number of experiments; 2) modeling and simulation of clutter signal based on real signal characteristics and 3) the comparison of simulated and measured signals

On the Frequency and Altitude Resolutions in Incoherent-Scatter-Radar Measurements

Systematic distortions of the spectrum of the signal scattered from diffusive media, and limitations on the resolutions in frequency and altitude due to the finite receiver bandwidth and the finite transmitted-pulse duration are estimated, using the radar-ambiguity function. The requirements for frequency and altitude resolutions are incompatible in the filter-bank method (FBM) which directly measures the power spectrum. With the actual parameters of the ionosphere, the FBM is shown to be inconvenient for pulse radar measurements except those of higher altitudes and/or with higher radar frequencies. In the correlation-function method (CFM) which calculates the cross-correlation or autocorrelation function, the resolutions are independently determined in frequency and altitude. The pulse duration is concerned only with the resolution in altitude. The minimum duration is limited by the sensitivity of the radar system, while the maximum is limited by the characteristic time of fluctuations in the medium which scatter the radio waves. Various methods for measuring the autocorrelation function are also described

A Comprehensive Review on Design and Development of Human Breast Phantoms for Ultra-Wide Band Breast Cancer Imaging Systems

Microwave ultra-wide band UWB imaging system is a contemporary biomedical imaging technology for early detection of breast cancers. This imaging system requires the development of breast phantoms for experimental data analysis. In order to obtain realistic results, it is very important that these phantoms mimic the characteristics of real biological breast tissue as close as possible. For this purpose, scientists and engineers make use of the dielectric properties of human breast. This paper takes a survey of mathematical formulations used to determine biological dielectric properties and then takes a review of current breast phantoms being used in UWB imaging systems with reference to the analytical dielectric measurements. At present, breast phantoms are made, both, manually in laboratory utilizing different chemicals and also by using computational electromagnetic algorithms to introduce better heterogeneity in them. They can then easily be tested by doing computer simulations. In this review paper, emphasis is made on the phantoms which are made in laboratory for doing hardware experimentations.Microwave ultra-wide band UWB imaging system is a contemporary biomedical imaging technology for early detection of breast cancers. This imaging system requires the development of breast phantoms for experimental data analysis. In order to obtain realistic results, it is very important that these phantoms mimic the characteristics of real biological breast tissue as close as possible. For this purpose, scientists and engineers make use of the dielectric properties of human breast. This paper takes a survey of mathematical formulations used to determine biological dielectric properties and then takes a review of current breast phantoms being used in UWB imaging systems with reference to the analytical dielectric measurements. At present, breast phantoms are made, both, manually in laboratory utilizing different chemicals and also by using computational electromagnetic algorithms to introduce better heterogeneity in them. They can then easily be tested by doing computer simulations. In this review paper, emphasis is made on the phantoms which are made in laboratory for doing hardware experimentations

Hybrid Trilinear and Bilinear Programming for Aligning Partially Overlapping Point Sets

Alignment methods which can handle partially overlapping point sets and are invariant to the corresponding transformations are desirable in computer vision, with applications such as providing initial transformation configuration for local search based methods like ICP. To this end, we first show that the objective of the robust point matching (RPM) algorithm is a cubic polynomial. We then utilize the convex envelopes of trilinear and bilinear monomials to develop its lower bounding function. The resulting lower bounding problem can be efficiently solved via linear assignment and low dimensional convex quadratic programming. We next develop a branch-and-bound (BnB) algorithm which only branches over the transformation parameters and converges quickly. Experimental results demonstrated favorable performance of the proposed method over the state-of-the-art methods in terms of robustness and speed

The Self-Reflective Nature of Roman Polanski\u27s \u3cem\u3eMacbeth\u3c/em\u3e

Most people are tempted to get on the critical bandwagon which attends Roman Polanski\u27s cinema and to announce from there that his version of Macbeth (1971) is another in a continuing series of intensely personal cinematic statements Polanski has made about the violence which pervades the human condition. Beginning in 1958 with his allegorical short subject Two Men and a Wardrobe, evident also in his implicitly violent first feature film, Knife In The Water (1961), in Repulsion (1965), his study of psychological obsession, in Rosemary\u27s Baby (1968), his study of literal obsession, and clearly dominating Chinatown (1974), his study of individual and social decay, there recurs in the work of this director a preoccupation with man\u27s destructive tendencies toward other men. Formalist critics may delight in examining the Polanski canon because of the patterned consistency evident there. Biographical critics are likely to relish analysis of his career because of the undeniable relationship between his life and his art

Noncontact Seismocardiogram Signal Detection Using Microwave Doppler Radar

The objective of the research is to achieve non-contact detection of seismocardiogram (SCG), a representation of mechanical heart motion, using microwave Doppler radar system. The increase in demand for health monitoring requires robust, reliable, and accurate remote detection of cardiac signals. Due to its ability to penetrate non-metal obstacles, microwave Doppler radar is promising to provide a non-contact and unobtrusive measurement. In this dissertation, both the hardware system and the signal processing approaches are developed for providing an accurate and reliable measurement of cardiac signals using the microwave Doppler radar. First, a noise suppression scheme and a clutter removal strategy are investigated to improve the performance of a microwave Doppler radar system. Then, an investigation is conducted to demonstrate the effectiveness of using a radar signal to represent SCG, and a standalone method is developed to extract the SCG features from the radar signal without using a contact electrocardiogram (ECG) signal that the conventional methods rely on. With the development of the hardware system and signal processing approaches, the complete non-contact measurement and analysis of cardiac signals can be achieved.Ph.D

Calibration of physically-based distributed rainfall-runoff model with radar data

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1995.Includes bibliographical references (leaves 119-122).by Yanlong Zhang.M.S