2,868 research outputs found
Maximum likelihood estimation of cloud height from multi-angle satellite imagery
We develop a new estimation technique for recovering depth-of-field from
multiple stereo images. Depth-of-field is estimated by determining the shift in
image location resulting from different camera viewpoints. When this shift is
not divisible by pixel width, the multiple stereo images can be combined to
form a super-resolution image. By modeling this super-resolution image as a
realization of a random field, one can view the recovery of depth as a
likelihood estimation problem. We apply these modeling techniques to the
recovery of cloud height from multiple viewing angles provided by the MISR
instrument on the Terra Satellite. Our efforts are focused on a two layer cloud
ensemble where both layers are relatively planar, the bottom layer is optically
thick and textured, and the top layer is optically thin. Our results
demonstrate that with relative ease, we get comparable estimates to the M2
stereo matcher which is the same algorithm used in the current MISR standard
product (details can be found in [IEEE Transactions on Geoscience and Remote
Sensing 40 (2002) 1547--1559]). Moreover, our techniques provide the
possibility of modeling all of the MISR data in a unified way for cloud height
estimation. Research is underway to extend this framework for fast, quality
global estimates of cloud height.Comment: Published in at http://dx.doi.org/10.1214/09-AOAS243 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
A New Method of Multi-Criteria Analysis for Evaluation and Decision Making by Dominant Criterion
© 2019-Vilnius University. This paper introduces a new method for multi-criteria analyses where the failure to meet the dominant criterion of an alternative causes low values for the entire alternative. In this method, the introduction of new alternatives into the multi-criteria model does not affect the existing alternatives in the model. The new method was applied for the rating of ten websites of dental clinics in Serbia, which provide prosthetic services to tourists. The dominant criterion was the amount of information provided by the site
Preparing Students for the Advanced Manufacturing Environment Through Robotics, Mechatronics, and Automation Training
Automation is one of the key areas for modern manufacturing systems. It requires coordination of different machines to support manufacturing operations in a company. Recent studies show that there is a gap in the STEM workforce preparation in regards to highly automated production environments. Industrial robots have become an essential part of these semi-automated and automated manufacturing systems. Their control and programming requires adequate education and training in robotics theory and applications. Various engineering technology departments offer different courses related to the application of robotics. These courses are a great way to inspire students to learn about science, math, engineering, and technology while providing them with workforce skills. However, some challenges are present in the delivery of such courses. One of these challenges includes the enrollment of students who come from different engineering departments and backgrounds. Such a multidisciplinary group of students can pose a challenge for the instructor to successfully develop the courses and match the content to different learning styles and math levels. To overcome that challenge, and to spark students\u27 interest, the certified education robot training can greatly support the teaching of basic and advanced topics in robotics, kinematics, dynamics, control, modeling, design, CAD/CAM, vision, manufacturing systems, simulation, automation, and mechatronics. This paper will explain how effective this course can be in unifying different engineering disciplines when using problem solving related to various important manufacturing automaton problems. These courses are focused on educational innovations related to the development of student competency in the use of equipment and tools common to the discipline, and associated curriculum development at three public institutions, in three different departments of mechanical engineering technology. Through these courses students make connections between the theory and real industrial applications. This aspect is especially important for tactile or kinesthetic learners who learn through experiencing and doing things. They apply real mathematical models and understand physical implications through labs on industrial grade robotic equipment and mobile robots
D'Alembert sums for vibrating bar with viscous ends
We describe a new method for finding analytic solutions to some
initial-boundary problems for partial differential equations with constant
coefficients. The method is based on expanding the denominator of the Laplace
transformed Green's function of the problem into a convergent geometric series.
If the denominator is a linear combination of exponents with real powers one
obtains a closed form solution as a sum with finite but time dependent number
of terms. We call it a d'Alembert sum. This representation is computationally
most effective for small evolution times, but it remains valid even when the
system of eigenmodes is incomplete and the eigenmode expansion is unavailable.
Moreover, it simplifies in such cases.
In vibratory problems d'Alembert sums represent superpositions of original
and partially reflected traveling waves. They generalize the d'Alembert type
formulas for the wave equation, and reduce to them when original waves can
undergo only finitely many reflections in the entire course of evolution. The
method is applied to vibrations of a bar with dampers at each end and at some
internal point. The results are illustrated by computer simulations and
comparisons to modal and FEM solutions.Comment: 18 pages, 8 figure
Period Batch Control - A Production Planning System Applied to Virtual Manufacturing Cells
Period Batch Control (PBC) system has been known for its implementation with the classical group technology (GT) cells, and it has been known for its simplicity. The main production planning decisions concern the choice of the period length and the stage number and contents. Also, in order to better integrate the production planning with the application of GT cells at the shop floor, the concept of virtual manufacturing cells has been applied. Since virtual cells configurations are changing periodically, a model for implementing the PBC system into virtual manufacturing cells environment is developed. The model enables alignment of the PBC principles and rules with virtual cell design goals. Model is tested on the case study of furniture production. With the use of scheduling software, different scheduling rules were simulated for four production weeks. The experimental results from these for production weeks show how the choice of PBC parameters impacts the virtual cells configurations, machine sharing and utilization
Use of ePortfolio as Integrated Learning Strategy in Computer Integrated Manufacturing Online Course
Integrated learning is a vital strategy for engaging undergraduate Engineering students in the higher levels of learning, as it encourages students to reflect on their learning processes and draw connections between course-work and real-world experiences. Specifically, ePortfolios encourage novice engineers to consider their learning processes over time, drawing connections between coursework and their intended profession, as well as cultivating an online identity that supports their efforts to pursue a career in Engineering. The use of ePortfolios is one method for fostering integrative learning, focusing on the application of digital communication and assessment and awareness of self-competence. By training students to archive digital artifacts related to their learning, ePortfolios encourage student to draw connections between course content and their future careers. Digital portfolios also provide students with the opportunity to develop an online presence, demonstrating through multi-modal content the skills they gained through their education. At the same time, students develop basic digital literacies, from creating and curating digital artifacts throughout the learning process, managing their data, to displaying knowledge and skills which are important for their future engineering careers. This paper examines the efforts of students at Old Dominion University (ODU), Norfolk, Virginia who created ePortfolios in a variety of contexts, as a part of a course which was specifically developed as part of a university wide ePortfolio initiative. In May 2015, faculty attended a professional development workshop, eP3: Praxis, Process, and Production, in order to learn about basic ePortfolio strategies and ways in which to foster students\u27 archival habits. The project presented in this paper was established in the summer 2015 semester in the undergraduate course Computer Integrated Manufacturing at the senior level
Integrating Cobots in Engineering Technology Education
Collaborative robots or CoBots, unlike traditional robots, are safe and flexible enough to work harmoniously with humans. Exploiting the efficiency of automated operations and the flexibility of manual operations in one process can improve productivity and worker job satisfaction. CoBots technology has been experiencing strong growth in different areas such as ground transportation, food-processing industry, car manufacturing, and naval or aeronautical engineering. Current CoBots education and training opportunities are rare or non-existent in university environments. In response to this need, we developed several CoBots modules which will be integrated in the current robotics and mechatronics courses. In this paper we are presenting one common module which will be integrated in both, robotics and mechatronic courses. This module is about modeling and validation of Baxter Collaborative robot kinematics using Matlab tools. Through the validation and visualization of the kinematic equations, students will be able to connect the robotic and mechatronic theory with different applications using the latest technology
In Vitro Screening of α-Amylase Inhibition by Selected Terpenes from Essential Oils
Purpose: To assess some terpenes from herbal products for possible inhibitory effects on serum α- amylase in order to ascertain their potential usefulness in the prevention and/or treatment of diabetes Type 2.Methods: Solutions of terpenes (citral, eukalyptol, β-pinene, myrcene, eugenol and terpineol) in deonized water were prepared by ultrasonic and manual mixing in four different concentrations ranging from 0.39 – 5.50 µmol cm-3. Commercial sera (with normal-N and high-H enzyme activity) were used as a source of α-amylase. α-Amylase activity was determined by standard methods using an automated analyzer.Results: All the selected terpenes at their maximal concentrations inhibited α-amylase in N-sera in the range 9.68 – 38.70 and 10.71 - 25.00 % for ultrasonic and manual mixing, respectively, while in H-sera, inhibition was in the range 17.10 - 21.05 and 13.58 – 25.92 % for ultrasonic and manual mixing, respectively. Regardless of the concentration of the inhibitor or the method of mixing, citral was the strongest inhibitor of α-amylase.Conclusion: The selected terpenes, in their appropriate concentrations, influence α-amylase activity to varying degrees. Principal component and agglomerative hierarchical analysis reveal that the most significant factor in α-amylase inhibition is the mode of mixing the samples, rather than their concentrations.Keywords: α-Amylase, β-Pinene, Citral, Diabetes, Essential oil, Eugenol, Eukalyptol, Myrcene, Terpenes, Terpineo
Exploration of a Polarized Surface Bidirectional Reflectance Model Using the Ground-Based Multiangle Spectropolarimetric Imager
Accurate characterization of surface reflection is essential for retrieval of aerosols using downward-looking remote sensors. In this paper, observations from the Ground-based Multiangle SpectroPolarimetric Imager (GroundMSPI) are used to evaluate a surface polarized bidirectional reflectance distribution function (PBRDF) model. GroundMSPI is an eight-band spectropolarimetric camera mounted on a rotating gimbal to acquire pushbroom imagery of outdoor landscapes. The camera uses a very accurate photoelastic-modulator-based polarimetric imaging technique to acquire Stokes vector measurements in three of the instrument's bands (470, 660, and 865 nm). A description of the instrument is presented, and observations of selected targets within a scene acquired on 6 January 2010 are analyzed. Data collected during the course of the day as the Sun moved across the sky provided a range of illumination geometries that facilitated evaluation of the surface model, which is comprised of a volumetric reflection term represented by the modified Rahman-Pinty-Verstraete function plus a specular reflection term generated by a randomly oriented array of Fresnel-reflecting microfacets. While the model is fairly successful in predicting the polarized reflection from two grass targets in the scene, it does a poorer job for two manmade targets (a parking lot and a truck roof), possibly due to their greater degree of geometric organization. Several empirical adjustments to the model are explored and lead to improved fits to the data. For all targets, the data support the notion of spectral invariance in the angular shape of the unpolarized and polarized surface reflection. As noted by others, this behavior provides valuable constraints on the aerosol retrieval problem, and highlights the importance of multiangle observations.NASAJPLCenter for Space Researc
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