Feature tracking and matching in video using programmable graphics hardware

This paper describes novel implementations of the KLT feature tracking and SIFT feature extraction algorithms that run on the graphics processing unit (GPU) and is suitable for video analysis in real-time vision systems. While significant acceleration over standard CPU implementations is obtained by exploiting parallelism provided by modern programmable graphics hardware, the CPU is freed up to run other computations in parallel. Our GPU-based KLT implementation tracks about a thousand features in real-time at 30 Hz on 1,024 × 768 resolution video which is a 20 times improvement over the CPU. The GPU-based SIFT implementation extracts about 800 features from 640 × 480 video at 10 Hz which is approximately 10 times faster than an optimized CPU implementation.     

Lines in one orthographic and two perspective views

We introduce a linear algorithm to recover the Euclidean motion between an orthographic and two perspective cameras from straight line correspondences filling the gap in the analysis of motion estimation from line correspondences for various projection models. The general relationship between lines in three views is described by the trifocal tensor. Euclidean structure from motion for three perspective views is a special case in which the relationship is defined by a collection of three matrices. Here, we describe the case of two calibrated perspective views and an orthographic view. Similar to the other cases, our linear algorithm requires 13 or more line correspondences to recover 27 coefficients of the trifocal tensor.     

Dependency of removal efficiency on electrode arrangements in the treatment of oily wastewaters by electrocoagulation

Turbidity and chemical oxygen demand (COD) removal efficiencies were analyzed depending on electrode layouts by performing electrocoagulation experiments using horizontal and vertical electrochemical cells. Multiple aluminum plate electrodes were placed into different sections of the electrochemical cells. Removal efficiencies at the horizontal electrochemical cell were always higher than the one’s obtained from the vertical electrochemical cell. But the use of vertical electrochemical cell consumed less energy during the electrocoagulation tests. The highest COD removal efficiencies were 97% and 88% in the horizontal and vertical electrochemical cells, respectively. However, the energy consumption for COD removal in the horizontal electrochemical cell was 47% higher than the energy consumed in the vertical electrochemical cell.     

Performance Assessment of a Potato Crisp Frying Process

Frying is a common and popular cooking method, which has been widely used in food manufacturing, though it is a very energy-intensive process. Energy analysis has been commonly used to assess the performance of fryers. In this study, we attempted to exergetically assess the performance of a potato crisp frying system, which consists of three main components, a combustor, a heat exchanger, and a fryer. In the analysis, we utilized the actual operational data obtained from the literature. We determined exergy destruction in each system component and the whole system. We calculated universal and functional exergy efficiency values for the system components and compared them with each other. We also undertook a parametric study to investigate how the overall cycle performance was affected by changing the reference environment temperature and some operating conditions. We illustrated the exergy results through the Grassmann (exergy loss and flow) diagram. We calculated the universal exergetic efficiency values of 58, 82, and 77% for the combustor, heat exchanger, and fryer, respectively, with a universal exergetic efficiency value of 4% for the whole frying system. We found that the fryer had the highest functional exergetic efficiency value of 74%, followed by the heat exchanger with 47% and the combustor with 0.08%.     

Alternative regional specification and convergence of U.S. regional growth rates

We apply absolute beta convergence techniques to cross sectional per capita income data for alternative specifications of U.S. regions in order to detect whether U.S. regional growth rates are converging over relatively recent time periods. We also explore whether estimates of convergence differ between economic and political region specifications. We show that convergence of growth rates across regions of the U.S. has continued in modern times (1969–1997) for almost any regional specification and for all time frames considered. We do find, however, some difference in convergence rates between economic and political regions. Convergence coefficients, however, are remarkably similar across alternative economic region specifications. An earlier version of this paper was presented in February 2003 at the 42nd annual meetings of the Western Regional Science Association in Rio Rico, Arizona. We would like to thank our session participants in Rio Rico and three anonymous referees for helpful comments. Any remaining errors or oversights, however, are entirely our responsibility.     

IEEE 802.16J relay-based wireless access networks: an overview [recent advances and evolution of WLAN and WMAN standards]

Multihop wireless systems have the potential to offer improved coverage and capacity over single-hop radio access systems. Standards development organizations are considering how to incorporate such techniques into new standards. One such initiative is the IEEE 802.16j standardization activity, adding relay capabilities to IEEE 802.16 systems. This article provides an overview of this relay-based technology, focusing on some of the most pertinent aspects. In particular, the different modes of operation (transparent and non-transparent), framing structures, and network entry procedures are described. Some consideration of the issues in designing such systems is then given, which highlights when different features within the standard are most appropriate. As these systems are very new, many open issues remain to be resolved.     

Investigation of flow properties in natural streams using the entropy concept

This paper examines the discharge and velocity distributions in natural open channel flows using the entropy theory. Flow measurements were carried out at four different cross‐sections in central Turkey. The mean and maximum velocities at these stations exhibited a linear distribution and the entropy parameter was calculated to be M=1.31. Using this value, discharges for all flow conditions were calculated as a function of the measured maximum velocities (u_max). It was observed that the u_max/H and z_max/H ratios remained relatively constant when 0.2≤y/T≤0.8, especially for the wider channels. Using these constant values for each station, u_max and z_max could be determined solely as a function of the water depth H. Although the calculated velocities were higher than those measured at some verticals, the entropy‐based approach presents an attractive alternative to the traditional flow‐measurement techniques for the determination of flow properties because of its simplicity and quick application.     

Negative attitudes to transition in post-communist Albania and acute coronary syndrome.

Objective: The authors assessed the association of acute coronary syndrome (ACS) with attitudes to the socioeconomic aspects of rapid change in transitional Albania. Design: A population-based case–control study conducted in Tirana, Albania, in 2003–2006 included 467 nonfatal ACS patients (370 men, 97 women; 88% response) and a population-sampled control group (469 men, 268 women; 69% response). Main Outcome Measures: Reaction to transition was assessed as a composite score of 3 items capturing attitudes toward socioeconomic aspects of transition in Albania. Results: Using logistic regression, there was a strong linear relationship of the attitude score with ACS. When categorized as negative, intermediate, or positive attitudes, the age- and sex-adjusted odds ratio (OR) for the negative versus positive categories was 3.0; 95% confidence interval (CI) = 2.1, 4.3; p for linear trend     

A systematic approach to integral snap-fit attachment design

Traditional integral snap-fit attachment design focuses almost exclusively on the individual locking features, such as cantilever hooks, bayonet-fingers, compressive hooks and others. The positioning and orientation of other significant features on parts, such as those that facilitate or enhance engagement and eliminate unwanted degrees of freedom left by locking features, i.e. locating features and enhancements, are not considered. This paper builds on relatively new methodologies and guidelines for arranging all attachment features on plastic parts comprising snap-fit assembly. Classification of features into categories of locking features, locating features and enhancements of these is used as the basis for discussion. A systematic approach to attachment design is presented.     

Phase transformations in Ti-6Al-4V-xH alloys

Microstructures, phases, and phase transformations in Ti-6Al-4V alloy specimens containing 0, 10, 20, and 30 at. pct hydrogen were investigated using optical microscopy (OM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and microhardness testing. Alloying with hydrogen was achieved by holding the specimens in a pure hydrogen atmosphere of different pressures at 780 °C for 24 hours. The phases present in the temperature range of 20 °C to 1000 °C were determined by microstructural characterization of the specimens quenched from different temperatures. Increasing the hydrogen addition from 0 to 30 at. pct lowered the beta-transus temperature of the alloy from 1005 °C to 815 °C, significantly slowed down the kinetics of the beta-to-alpha transformation, and led to formation of an orthorhombic martensite instead of the hexagonal martensite found in quenched specimens containing 0 pct H. A hydride phase was detected in specimens containing 20 and 30 at. pct hydrogen. The time-temperature-transformation (TTT) diagrams for beta-phase decomposition were determined at different hydrogen concentrations. The nose temperature for the beginning of the transformation decreased from 725 °C to 580 °C, and the nose time increased from 12 seconds to 42 minutes when the hydrogen concentration was increased from 0 to 30 at. pct.