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Sample records for problemes sanitaires poses

  1. Student-Posed Problems

    NASA Astrophysics Data System (ADS)

    Harper, Kathleen A.; Etkina, Eugenia

    2002-10-01

    As part of weekly reports,1 structured journals in which students answer three standard questions each week, they respond to the prompt, If I were the instructor, what questions would I ask or problems assign to determine if my students understood the material? An initial analysis of the results shows that some student-generated problems indicate fundamental misunderstandings of basic physical concepts. A further investigation explores the relevance of the problems to the week's material, whether the problems are solvable, and the type of problems (conceptual or calculation-based) written. Also, possible links between various characteristics of the problems and conceptual achievement are being explored. The results of this study spark many more questions for further work. A summary of current findings will be presented, along with its relationship to previous work concerning problem posing.2 1Etkina, E. Weekly Reports;A Two-Way Feedback Tool, Science Education, 84, 594-605 (2000). 2Mestre, J.P., Probing Adults Conceptual Understanding and Transfer of Learning Via Problem Posing, Journal of Applied Developmental Psychology, 23, 9-50 (2002).

  2. Problem Posing with the Multiplication Table

    ERIC Educational Resources Information Center

    Dickman, Benjamin

    2014-01-01

    Mathematical problem posing is an important skill for teachers of mathematics, and relates readily to mathematical creativity. This article gives a bit of background information on mathematical problem posing, lists further references to connect problem posing and creativity, and then provides 20 problems based on the multiplication table to be…

  3. Ill-posed problems in mechanics

    NASA Astrophysics Data System (ADS)

    Zhuravlev, V. Ph.

    2016-09-01

    The notion of ill-posed initial and boundary value problems for partial differential equations was introduced by Hadamard, who also presented the first example of an ill-posed problem for a specific partial differential equation. At the same time, there are numerous examples of ill-posed problems in any field of mechanics. Hadamard and some of his successors believed that any ill-posed problem has no physical meaning and such problems should not be posed. The present paper contains several examples of ill-posed problems. We show that if one deals with an applied problem, then overcoming the ill-posedness mathematically can help one to improve the structure in practice, which justifies the study of ill-posed problems.

  4. Problem Posing and Solving with Mathematical Modeling

    ERIC Educational Resources Information Center

    English, Lyn D.; Fox, Jillian L.; Watters, James J.

    2005-01-01

    Mathematical modeling is explored as both problem posing and problem solving from two perspectives, that of the child and the teacher. Mathematical modeling provides rich learning experiences for elementary school children and their teachers.

  5. Pose and Solve Varignon Converse Problems

    ERIC Educational Resources Information Center

    Contreras, José N.

    2014-01-01

    The activity of posing and solving problems can enrich learners' mathematical experiences because it fosters a spirit of inquisitiveness, cultivates their mathematical curiosity, and deepens their views of what it means to do mathematics. To achieve these goals, a mathematical problem needs to be at the appropriate level of difficulty,…

  6. Numerical Regularization of Ill-Posed Problems.

    DTIC Science & Technology

    1980-07-09

    Unione Matematica Italiana. 4. The parameter choice problem in linear regularization: a mathematical introduction, in "Ill-Posed Problems: Theory and...vector b which is generally unavailable (see [21], [22]). Kdckler [33] has shon however that in the case of Tikhonov regularization for matrices it may

  7. Quadratic optimization in ill-posed problems

    NASA Astrophysics Data System (ADS)

    Ben Belgacem, F.; Kaber, S.-M.

    2008-10-01

    Ill-posed quadratic optimization frequently occurs in control and inverse problems and is not covered by the Lax-Milgram-Riesz theory. Typically, small changes in the input data can produce very large oscillations on the output. We investigate the conditions under which the minimum value of the cost function is finite and we explore the 'hidden connection' between the optimization problem and the least-squares method. Eventually, we address some examples coming from optimal control and data completion, showing how relevant our contribution is in the knowledge of what happens for various ill-posed problems. The results we state bring a substantial improvement to the analysis of the regularization methods applied to the ill-posed quadratic optimization problems. Indeed, for the cost quadratic functions bounded from below the Lavrentiev method is just the Tikhonov regularization for the 'hidden least-squares' problem. As a straightforward result, Lavrentiev's regularization exhibits better regularization and convergence results than expected at first glance.

  8. Pre-Service Teachers' Free and Structured Mathematical Problem Posing

    ERIC Educational Resources Information Center

    Silber, Steven; Cai, Jinfa

    2017-01-01

    This exploratory study examined how pre-service teachers (PSTs) pose mathematical problems for free and structured mathematical problem-posing conditions. It was hypothesized that PSTs would pose more complex mathematical problems under structured posing conditions, with increasing levels of complexity, than PSTs would pose under free posing…

  9. Pre-Service Teachers' Free and Structured Mathematical Problem Posing

    ERIC Educational Resources Information Center

    Silber, Steven; Cai, Jinfa

    2017-01-01

    This exploratory study examined how pre-service teachers (PSTs) pose mathematical problems for free and structured mathematical problem-posing conditions. It was hypothesized that PSTs would pose more complex mathematical problems under structured posing conditions, with increasing levels of complexity, than PSTs would pose under free posing…

  10. Skill Levels of Prospective Physics Teachers on Problem Posing

    ERIC Educational Resources Information Center

    Cildir, Sema; Sezen, Nazan

    2011-01-01

    Problem posing is one of the topics which the educators thoroughly accentuate. Problem posing skill is defined as an introvert activity of a student's learning. In this study, skill levels of prospective physics teachers on problem posing were determined and their views on problem posing were evaluated. To this end, prospective teachers were given…

  11. Probabilistic Solution of Ill-Posed Problems in Computational Vision.

    DTIC Science & Technology

    1987-03-01

    SOLUTION OF ILL - POSED PROBLEMS IN 1/t I CAMBRIDGE ARTIFICIAL INTELLIGENCE LAB UNLASIIE...TECHNOLOGY ARTIFICIAL INTELLIGENCE LABORATORY A. I. Memo 897 March 1987 Probabilistic Solution of Ill - Posed Problems in Computational Vision J. Marroquin... solution (a) exists, (b) is unique and (c) depends continuously on the initial data. Ill - posed problems fail to satisfy one or more of these

  12. Artifacts as Sources for Problem-Posing Activities

    ERIC Educational Resources Information Center

    Bonotto, Cinzia

    2013-01-01

    The problem-posing process represents one of the forms of authentic mathematical inquiry which, if suitably implemented in classroom activities, could move well beyond the limitations of word problems, at least as they are typically utilized. The two exploratory studies presented sought to investigate the impact of "problem-posing" activities when…

  13. The Art of Problem Posing. 3rd Edition

    ERIC Educational Resources Information Center

    Brown, Stephen I.; Walter, Marion I.

    2005-01-01

    The new edition of this classic book describes and provides a myriad of examples of the relationships between problem posing and problem solving, and explores the educational potential of integrating these two activities in classrooms at all levels. "The Art of Problem Posing, Third Edition" encourages readers to shift their thinking…

  14. Helping Young Students to Better Pose an Environmental Problem

    ERIC Educational Resources Information Center

    Pruneau, Diane; Freiman, Viktor; Barbier, Pierre-Yves; Langis, Joanne

    2009-01-01

    Grade 3 students were asked to solve a sedimentation problem in a local river. With scientists, students explored many aspects of the problem and proposed solutions. Graphic representation tools were used to help students to better pose the problem. Using questionnaires and interviews, researchers observed students' capacity to pose the problem…

  15. The Posing of Arithmetic Problems by Mathematically Talented Students

    ERIC Educational Resources Information Center

    Espinoza González, Johan; Lupiáñez Gómez, José Luis; Segovia Alex, Isidoro

    2016-01-01

    Introduction: This paper analyzes the arithmetic problems posed by a group of mathematically talented students when given two problem-posing tasks, and compares these students' responses to those given by a standard group of public school students to the same tasks. Our analysis focuses on characterizing and identifying the differences between the…

  16. The Posing of Arithmetic Problems by Mathematically Talented Students

    ERIC Educational Resources Information Center

    Espinoza González, Johan; Lupiáñez Gómez, José Luis; Segovia Alex, Isidoro

    2016-01-01

    Introduction: This paper analyzes the arithmetic problems posed by a group of mathematically talented students when given two problem-posing tasks, and compares these students' responses to those given by a standard group of public school students to the same tasks. Our analysis focuses on characterizing and identifying the differences between the…

  17. Developing Teachers' Subject Didactic Competence through Problem Posing

    ERIC Educational Resources Information Center

    Ticha, Marie; Hospesova, Alena

    2013-01-01

    Problem posing (not only in lesson planning but also directly in teaching whenever needed) is one of the attributes of a teacher's subject didactic competence. In this paper, problem posing in teacher education is understood as an educational and a diagnostic tool. The results of the study were gained in pre-service primary school teacher…

  18. Posing Problems to Understand Children's Learning of Fractions

    ERIC Educational Resources Information Center

    Cheng, Lu Pien

    2013-01-01

    In this study, ways in which problem posing activities aid our understanding of children's learning of addition of unlike fractions and product of proper fractions was examined. In particular, how a simple problem posing activity helps teachers take a second, deeper look at children's understanding of fraction concepts will be discussed. The…

  19. Creativity and Mathematical Problem Posing: An Analysis of High School Students' Mathematical Problem Posing in China and the USA

    ERIC Educational Resources Information Center

    Van Harpen, Xianwei Y.; Sriraman, Bharath

    2013-01-01

    In the literature, problem-posing abilities are reported to be an important aspect/indicator of creativity in mathematics. The importance of problem-posing activities in mathematics is emphasized in educational documents in many countries, including the USA and China. This study was aimed at exploring high school students' creativity in…

  20. Embedding Game-Based Problem-Solving Phase into Problem-Posing System for Mathematics Learning

    ERIC Educational Resources Information Center

    Chang, Kuo-En; Wu, Lin-Jung; Weng, Sheng-En; Sung, Yao-Ting

    2012-01-01

    A problem-posing system is developed with four phases including posing problem, planning, solving problem, and looking back, in which the "solving problem" phase is implemented by game-scenarios. The system supports elementary students in the process of problem-posing, allowing them to fully engage in mathematical activities. In total, 92 fifth…

  1. Embedding Game-Based Problem-Solving Phase into Problem-Posing System for Mathematics Learning

    ERIC Educational Resources Information Center

    Chang, Kuo-En; Wu, Lin-Jung; Weng, Sheng-En; Sung, Yao-Ting

    2012-01-01

    A problem-posing system is developed with four phases including posing problem, planning, solving problem, and looking back, in which the "solving problem" phase is implemented by game-scenarios. The system supports elementary students in the process of problem-posing, allowing them to fully engage in mathematical activities. In total, 92 fifth…

  2. Investigation of Problem-Solving and Problem-Posing Abilities of Seventh-Grade Students

    ERIC Educational Resources Information Center

    Arikan, Elif Esra; Ünal, Hasan

    2015-01-01

    This study aims to examine the effect of multiple problem-solving skills on the problem-posing abilities of gifted and non-gifted students and to assess whether the possession of such skills can predict giftedness or affect problem-posing abilities. Participants' metaphorical images of problem posing were also explored. Participants were 20 gifted…

  3. Using Problem-Posing Dialogue in Adult Literacy Education.

    ERIC Educational Resources Information Center

    Nixon-Ponder, Sarah

    1995-01-01

    Problem-posing is a tool for developing and strengthening critical thinking skills. It is an inductive questioning process that structures dialog in the classroom. Five steps include describing the content, defining the problem, personalizing it, discussing it, and discussing alternatives. (Author/JOW)

  4. Mathematical Thinking and Creativity through Mathematical Problem Posing and Solving

    ERIC Educational Resources Information Center

    Ayllón, María F.; Gómez, Isabel A.; Ballesta-Claver, Julio

    2016-01-01

    This work shows the relationship between the development of mathematical thinking and creativity with mathematical problem posing and solving. Creativity and mathematics are disciplines that do not usually appear together. Both concepts constitute complex processes sharing elements, such as fluency (number of ideas), flexibility (range of ideas),…

  5. Enhancing Students' Communication Skills through Problem Posing and Presentation

    ERIC Educational Resources Information Center

    Sugito; E. S., Sri Mulyani; Hartono; Supartono

    2017-01-01

    This study was to explore how enhance communication skill through problem posing and presentation method. The subjects of this research were the seven grade students Junior High School, including 20 male and 14 female. This research was conducted in two cycles and each cycle consisted of four steps, they were: planning, action, observation, and…

  6. A Perspective for Examining the Link between Problem Posing and Problem Solving

    ERIC Educational Resources Information Center

    Cai, Jinfa; Hwang, Stephen

    2003-01-01

    In a previous study, we posited a link between Chinese sixth grade students' problem solving and problem posing based on a pattern-formation strategy (Cai & Hwang, 2002). A similar parallel structure between problem solving and problem posing did not obtain for the U.S. sixth graders in the study. The present study attempts to locate this type of…

  7. Investigating Mathematics Teachers Candidates' Knowledge about Problem Solving Strategies through Problem Posing

    ERIC Educational Resources Information Center

    Ünlü, Melihan

    2017-01-01

    The aim of the study was to determine mathematics teacher candidates' knowledge about problem solving strategies through problem posing. This qualitative research was conducted with 95 mathematics teacher candidates studying at education faculty of a public university during the first term of the 2015-2016 academic year in Turkey. Problem Posing…

  8. An investigation of U.S. and Chinese students' mathematical problem posing and problem solving

    NASA Astrophysics Data System (ADS)

    Cai, Jinfa

    1998-04-01

    This study explored the mathematical problem posing and problem solving of 181 U.S. and 223 Chinese sixth-grade students. It is part of a continuing effort to examine U.S. and Chinese students' performance by conducting a cognitive analysis of student responses to mathematical problem-posing and problem-solving tasks. The findings of this study provide further evidence that, while Chinese students outperform U.S. students on computational tasks, there are many similarities and differences between U.S. and Chinese students in performing relatively novel tasks. Moreover, the findings of this study suggest that a direct link between mathematical problem posing and problem solving found in earlier studies for U.S. students is true for Chinese students as well.

  9. Using Problem-Posing Dialogue in Adult Literacy Education. Teacher to Teacher.

    ERIC Educational Resources Information Center

    Nixon-Ponder, Sarah

    Problem posing is a tool for developing and strengthening critical thinking skills. Freire expanded on the idea of active, participatory education through problem-posing dialogue, a method that transforms the students into critical coinvestigators in dialogue with the teacher. Problem posing begins by listening for students' issues. Teachers…

  10. Problem Posing as a Pedagogical Strategy: A Teacher's Perspective

    ERIC Educational Resources Information Center

    Staebler-Wiseman, Heidi A.

    2011-01-01

    Student problem posing has been advocated for mathematics instruction, and it has been suggested that problem posing can be used to develop students' mathematical content knowledge. But, problem posing has rarely been utilized in university-level mathematics courses. The goal of this teacher-as-researcher study was to develop and investigate…

  11. The Analysis of the Problems the Pre-Service Teachers Experience in Posing Problems about Equations

    ERIC Educational Resources Information Center

    Isik, Cemalettin; Kar, Tugrul

    2012-01-01

    The present study aimed to analyse the potential difficulties in the problems posed by pre-service teachers about first degree equations with one unknown and equation pairs with two unknowns. It was carried out with 20 pre-service teachers studying in the Department of Elementary Mathematics Educations at a university in Eastern Turkey. The…

  12. Testing a Comprehensive Model for Measuring Problem Solving and Problem Posing Skills of Primary Pupils

    ERIC Educational Resources Information Center

    Charalambous, Charalambos; Kyriakides, Leonidas; Philippou, George

    2003-01-01

    The study reported in this paper is an attempt to develop a comprehensive model of measuring problem solving and posing (PSP) skills based on Marshall's schema theory (ST). A battery of tests on PSP skills was administered to 5th and 6th grade Cypriot students (n=2519). The Rasch model was used and a scale was created for the battery of tests and…

  13. Analyzing Pre-Service Primary Teachers' Fraction Knowledge Structures through Problem Posing

    ERIC Educational Resources Information Center

    Kilic, Cigdem

    2015-01-01

    In this study it was aimed to determine pre-service primary teachers' knowledge structures of fraction through problem posing activities. A total of 90 pre-service primary teachers participated in this study. A problem posing test consisting of two questions was used and the participants were asked to generate as many as problems based on the…

  14. The Problems Posed and Models Employed by Primary School Teachers in Subtraction with Fractions

    ERIC Educational Resources Information Center

    Iskenderoglu, Tuba Aydogdu

    2017-01-01

    Students have difficulties in solving problems of fractions in almost all levels, and in problem posing. Problem posing skills influence the process of development of the behaviors observed at the level of comprehension. That is why it is very crucial for teachers to develop activities for student to have conceptual comprehension of fractions and…

  15. Ill-Posed Problems and Regularization Analysis in Early Vision,

    DTIC Science & Technology

    1984-04-01

    extended to other sensory L modalities and to some motor control problems. For instance, a recently proposed solution to the problem of executing a...Istituto di Analisi Globale, Firenze, 1982. Brady, J.M., Grimson, W.E.L., and Langridge, D.J. "Shape eacoding and subjective contours" First Annual

  16. A well posed boundary value problem in transonic gas dynamics

    NASA Technical Reports Server (NTRS)

    Sanz, J. M.

    1978-01-01

    A boundary value problem for the Tricomi equation was studied in connection with transonic gas dynamics. The transformed equation delta u plus 1/3Y u sub Y equals 0 in canonical coordinates was considered in the complex domain of two independent complex variables. A boundary value problem was then set by prescribing the real part of the solution on the boundary of the real unit circle. The Dirichlet problem in the upper unit semicircle with vanishing values of the solution at Y = 0 was solved explicitly in terms of the hypergeometric function for the more general Euler-Poisson-Darboux equation. An explicit representation of the solution was also given for a mixed Dirichlet and Neumann problem for the same equation and domain.

  17. Prospective Middle School Mathematics Teachers' Knowledge of Linear Graphs in Context of Problem-Posing

    ERIC Educational Resources Information Center

    Kar, Tugrul

    2016-01-01

    This study examined prospective middle school mathematics teachers' problem-posing skills by investigating their ability to associate linear graphs with daily life situations. Prospective teachers were given linear graphs and asked to pose problems that could potentially be represented by the graphs. Their answers were analyzed in two stages. In…

  18. Critical Inquiry across the Disciplines: Strategies for Student-Generated Problem Posing

    ERIC Educational Resources Information Center

    Nardone, Carroll Ferguson; Lee, Renee Gravois

    2011-01-01

    Problem posing is a higher-order, active-learning task that is important for students to develop. This article describes a series of interdisciplinary learning activities designed to help students strengthen their problem-posing skills, which requires that students become more responsible for their learning and that faculty move to a facilitator…

  19. Developing Pre-Service Teachers Understanding of Fractions through Problem Posing

    ERIC Educational Resources Information Center

    Toluk-Ucar, Zulbiye

    2009-01-01

    This study investigated the effect of problem posing on the pre-service primary teachers' understanding of fraction concepts enrolled in two different versions of a methods course at a university in Turkey. In the experimental version, problem posing was used as a teaching strategy. At the beginning of the study, the pre-service teachers'…

  20. The Significance of "Problem-Posing" Teaching in a Democratic Society. College Teaching Monograph.

    ERIC Educational Resources Information Center

    Ceyhun, Fikret

    A new teaching methodology, the "problem-posing" approach, is advocated in place of the traditional system of education. Experience in teaching the "Principles of Economics" course at the University of North Dakota is used as illustration. The problem-posing approach can create a learning atmosphere that is more conducive to…

  1. Problem-Posing Research in Mathematics Education: Looking Back, Looking Around, and Looking Ahead

    ERIC Educational Resources Information Center

    Silver, Edward A.

    2013-01-01

    In this paper, I comment on the set of papers in this special issue on mathematical problem posing. I offer some observations about the papers in relation to several key issues, and I suggest some productive directions for continued research inquiry on mathematical problem posing.

  2. The Effects of Problem Posing on Student Mathematical Learning: A Meta-Analysis

    ERIC Educational Resources Information Center

    Rosli, Roslinda; Capraro, Mary Margaret; Capraro, Robert M.

    2014-01-01

    The purpose of the study was to meta-synthesize research findings on the effectiveness of problem posing and to investigate the factors that might affect the incorporation of problem posing in the teaching and learning of mathematics. The eligibility criteria for inclusion of literature in the meta-analysis was: published between 1989 and 2011,…

  3. Generalizability Theory Research on Developing a Scoring Rubric to Assess Primary School Students' Problem Posing Skills

    ERIC Educational Resources Information Center

    Cankoy, Osman; Özder, Hasan

    2017-01-01

    The aim of this study is to develop a scoring rubric to assess primary school students' problem posing skills. The rubric including five dimensions namely solvability, reasonability, mathematical structure, context and language was used. The raters scored the students' problem posing skills both with and without the scoring rubric to test the…

  4. Critical Inquiry across the Disciplines: Strategies for Student-Generated Problem Posing

    ERIC Educational Resources Information Center

    Nardone, Carroll Ferguson; Lee, Renee Gravois

    2011-01-01

    Problem posing is a higher-order, active-learning task that is important for students to develop. This article describes a series of interdisciplinary learning activities designed to help students strengthen their problem-posing skills, which requires that students become more responsible for their learning and that faculty move to a facilitator…

  5. An Exploratory Framework for Handling the Complexity of Mathematical Problem Posing in Small Groups

    ERIC Educational Resources Information Center

    Kontorovich, Igor; Koichu, Boris; Leikin, Roza; Berman, Avi

    2012-01-01

    The paper introduces an exploratory framework for handling the complexity of students' mathematical problem posing in small groups. The framework integrates four facets known from past research: task organization, students' knowledge base, problem-posing heuristics and schemes, and group dynamics and interactions. In addition, it contains a new…

  6. An Investigation of Relationships between Students' Mathematical Problem-Posing Abilities and Their Mathematical Content Knowledge

    ERIC Educational Resources Information Center

    Van Harpen, Xianwei Y.; Presmeg, Norma C.

    2013-01-01

    The importance of students' problem-posing abilities in mathematics has been emphasized in the K-12 curricula in the USA and China. There are claims that problem-posing activities are helpful in developing creative approaches to mathematics. At the same time, there are also claims that students' mathematical content knowledge could be highly…

  7. Teachers Implementing Mathematical Problem Posing in the Classroom: Challenges and Strategies

    ERIC Educational Resources Information Center

    Leung, Shuk-kwan S.

    2013-01-01

    This paper reports a study about how a teacher educator shared knowledge with teachers when they worked together to implement mathematical problem posing (MPP) in the classroom. It includes feasible methods for getting practitioners to use research-based tasks aligned to the curriculum in order to encourage children to pose mathematical problems.…

  8. Problem-Posing Research in Mathematics Education: Looking Back, Looking Around, and Looking Ahead

    ERIC Educational Resources Information Center

    Silver, Edward A.

    2013-01-01

    In this paper, I comment on the set of papers in this special issue on mathematical problem posing. I offer some observations about the papers in relation to several key issues, and I suggest some productive directions for continued research inquiry on mathematical problem posing.

  9. An Investigation of Eighth Grade Students' Problem Posing Skills (Turkey Sample)

    ERIC Educational Resources Information Center

    Arikan, Elif Esra; Ünal, Hasan

    2015-01-01

    To pose a problem refers to the creative activity for mathematics education. The purpose of the study was to explore the eighth grade students' problem posing ability. Three learning domains such as requiring four operations, fractions and geometry were chosen for this reason. There were two classes which were coded as class A and class B. Class A…

  10. An Investigation of Relationships between Students' Mathematical Problem-Posing Abilities and Their Mathematical Content Knowledge

    ERIC Educational Resources Information Center

    Van Harpen, Xianwei Y.; Presmeg, Norma C.

    2013-01-01

    The importance of students' problem-posing abilities in mathematics has been emphasized in the K-12 curricula in the USA and China. There are claims that problem-posing activities are helpful in developing creative approaches to mathematics. At the same time, there are also claims that students' mathematical content knowledge could be highly…

  11. An Investigation of Eighth Grade Students' Problem Posing Skills (Turkey Sample)

    ERIC Educational Resources Information Center

    Arikan, Elif Esra; Ünal, Hasan

    2015-01-01

    To pose a problem refers to the creative activity for mathematics education. The purpose of the study was to explore the eighth grade students' problem posing ability. Three learning domains such as requiring four operations, fractions and geometry were chosen for this reason. There were two classes which were coded as class A and class B. Class A…

  12. Inflammatory bowel disease in adolescents: What problems does it pose?

    PubMed Central

    Lu, Ying; Markowitz, James

    2011-01-01

    Adolescents with inflammatory bowel disease face daily and long-term challenges that may be difficult for teenagers to manage. The developmental and psychosocial changes unique to this age group include becoming more autonomous and being more vulnerable to peer influence. These changes may lead to problems in medical management such as poor medication adherence and risky behavior. Being aware of these issues will help the medical team provide anticipatory guidance to address these concerns. PMID:21734775

  13. An Analog Model of Computation for the Ill-Posed Problems of Early Vision,

    DTIC Science & Technology

    1984-05-01

    Tikhonov , A.N. and Arsenin , V.Y., Solutions of ill - posed problems , Winston & Sons, Washington, D.C., 1977 . Torre...recent years (see especially Tikhonov and Arsenin , 1977 ; and Nashed, 1974). Ill - posed S problems of the form y - Az, (’) where A is a possibly nonlinear... problems are defined as such problems that do not have a unique solution that depends continuously on the data. Early vision

  14. The Relationship between Students' Problem Posing and Problem Solving Abilities and Beliefs: A Small-Scale Study with Chinese Elementary School Children

    ERIC Educational Resources Information Center

    Limin, Chen; Van Dooren, Wim; Verschaffel, Lieven

    2013-01-01

    The goal of the present study is to investigate the relationship between pupils' problem posing and problem solving abilities, their beliefs about problem posing and problem solving, and their general mathematics abilities, in a Chinese context. Five instruments, i.e., a problem posing test, a problem solving test, a problem posing questionnaire,…

  15. The residual method for regularizing ill-posed problems

    PubMed Central

    Grasmair, Markus; Haltmeier, Markus; Scherzer, Otmar

    2011-01-01

    Although the residual method, or constrained regularization, is frequently used in applications, a detailed study of its properties is still missing. This sharply contrasts the progress of the theory of Tikhonov regularization, where a series of new results for regularization in Banach spaces has been published in the recent years. The present paper intends to bridge the gap between the existing theories as far as possible. We develop a stability and convergence theory for the residual method in general topological spaces. In addition, we prove convergence rates in terms of (generalized) Bregman distances, which can also be applied to non-convex regularization functionals. We provide three examples that show the applicability of our theory. The first example is the regularized solution of linear operator equations on Lp-spaces, where we show that the results of Tikhonov regularization generalize unchanged to the residual method. As a second example, we consider the problem of density estimation from a finite number of sampling points, using the Wasserstein distance as a fidelity term and an entropy measure as regularization term. It is shown that the densities obtained in this way depend continuously on the location of the sampled points and that the underlying density can be recovered as the number of sampling points tends to infinity. Finally, we apply our theory to compressed sensing. Here, we show the well-posedness of the method and derive convergence rates both for convex and non-convex regularization under rather weak conditions. PMID:22345828

  16. Ill Posed Problems: Numerical and Statistical Methods for Mildly, Moderately and Severely Ill Posed Problems with Noisy Data.

    DTIC Science & Technology

    1980-02-01

    constraints,can be developed based on Laurent and Martinet (1969) ( personal communication, P.J. Laurent). It is intended that this will appear separately. If...Elfving and Herman (1979), Naparstek, personal communication). The first commercial machines discretized the problem at the start and solved the...Numerical aspects of some regularization methods and apolication to data collected in isolated dog heart experiments. Laboratorio di Analisi Numerica

  17. Investigation of learning environment for arithmetic word problems by problem posing as sentence integration in Indonesian language

    NASA Astrophysics Data System (ADS)

    Hasanah, N.; Hayashi, Y.; Hirashima, T.

    2017-02-01

    Arithmetic word problems remain one of the most difficult area of teaching mathematics. Learning by problem posing has been suggested as an effective way to improve students’ understanding. However, the practice in usual classroom is difficult due to extra time needed for assessment and giving feedback to students’ posed problems. To address this issue, we have developed a tablet PC software named Monsakun for learning by posing arithmetic word problems based on Triplet Structure Model. It uses the mechanism of sentence-integration, an efficient implementation of problem-posing that enables agent-assessment of posed problems. The learning environment has been used in actual Japanese elementary school classrooms and the effectiveness has been confirmed in previous researches. In this study, ten Indonesian elementary school students living in Japan participated in a learning session of problem posing using Monsakun in Indonesian language. We analyzed their learning activities and show that students were able to interact with the structure of simple word problem using this learning environment. The results of data analysis and questionnaire suggested that the use of Monsakun provides a way of creating an interactive and fun environment for learning by problem posing for Indonesian elementary school students.

  18. Numerical Solution of an Ill-Posed Problem Arising in Wind Tunnel Heat Transfer Data Reduction,

    DTIC Science & Technology

    1981-12-04

    Solutions of Ill - Posed Problems , A. H. Winston and Sons, 1977 . 6. Widder, D. V., The Heat Equation, Academic Press. 7. Richtmyer, R. D. and...DEC Al J B BELL. A B WAROLAW UNCLASSI ESWC WC/TR2l3lSBI.ADF5 046NL U" ~ a5 11111.5 N NSWC TR 82-32 cNUMERICAL SOLUTION OF AN ILL - POSED PROBLEM ...is ill - posed . A Tikhonov regularization procedure5 is then used to compute stable approximate solutions to the integral equation. In the

  19. Assessment of a Problem Posing Task in a Jamaican Grade Four Mathematics Classroom

    ERIC Educational Resources Information Center

    Munroe, Kayan Lloyd

    2016-01-01

    This paper analyzes how a teacher of mathematics used problem posing in the assessment of the cognitive development of 26 students at the grade-four level. The students, ages 8 to 10 years, were from a rural elementary school in western Jamaica. Using a picture as a prompt, students were asked to generate three arithmetic problems and to offer…

  20. Assessment of a Problem Posing Task in a Jamaican Grade Four Mathematics Classroom

    ERIC Educational Resources Information Center

    Munroe, Kayan Lloyd

    2016-01-01

    This paper analyzes how a teacher of mathematics used problem posing in the assessment of the cognitive development of 26 students at the grade-four level. The students, ages 8 to 10 years, were from a rural elementary school in western Jamaica. Using a picture as a prompt, students were asked to generate three arithmetic problems and to offer…

  1. Investigating the Impact of Field Trips on Teachers' Mathematical Problem Posing

    ERIC Educational Resources Information Center

    Courtney, Scott A.; Caniglia, Joanne; Singh, Rashmi

    2014-01-01

    This study examines the impact of field trip experiences on teachers' mathematical problem posing. Teachers from a large urban public school system in the Midwest participated in a professional development program that incorporated experiential learning with mathematical problem formulation experiences. During 2 weeks of summer 2011, 68 teachers…

  2. A well-posed optimal spectral element approximation for the Stokes problem

    NASA Technical Reports Server (NTRS)

    Maday, Y.; Patera, A. T.; Ronquist, E. M.

    1987-01-01

    A method is proposed for the spectral element simulation of incompressible flow. This method constitutes in a well-posed optimal approximation of the steady Stokes problem with no spurious modes in the pressure. The resulting method is analyzed, and numerical results are presented for a model problem.

  3. Investigating the Impact of Field Trips on Teachers' Mathematical Problem Posing

    ERIC Educational Resources Information Center

    Courtney, Scott A.; Caniglia, Joanne; Singh, Rashmi

    2014-01-01

    This study examines the impact of field trip experiences on teachers' mathematical problem posing. Teachers from a large urban public school system in the Midwest participated in a professional development program that incorporated experiential learning with mathematical problem formulation experiences. During 2 weeks of summer 2011, 68 teachers…

  4. Improving attitudes toward mathematics learning with problem posing in class VIII

    NASA Astrophysics Data System (ADS)

    Vionita, Alfha; Purboningsih, Dyah

    2017-08-01

    This research is classroom action research which is collaborated to improve student's behavior toward math and mathematics learning at class VIII by using problem posing approach. The subject of research is all of students grade VIIIA which consist of 32 students. This research has been held on two period, first period is about 3 times meeting, and second period is about 4 times meeting. The instrument of this research is implementation of learning observation's guidance by using problem posing approach. Cycle test has been used to measure cognitive competence, and questionnaire to measure the students' behavior in mathematics learning process. The result of research shows the students' behavior has been improving after using problem posing approach. It is showed by the behavior's criteria of students that has increasing result from the average in first period to high in second period. Furthermore, the percentage of test result is also improve from 68,75% in first period to 78,13% in second period. On the other hand, the implementation of learning observation by using problem posing approach has also improving and it is showed by the average percentage of teacher's achievement in first period is 89,2% and student's achievement 85,8%. These results get increase in second period for both teacher and students' achievement which are 94,4% and 91,11%. As a result, students' behavior toward math learning process in class VIII has been improving by using problem posing approach.

  5. Well-posed ADM equivalent of the Bondi-Sachs problem

    SciTech Connect

    Frittelli, Simonetta

    2006-06-15

    Every well-posed hyperbolic problem has an associated characteristic representation. In the case of the Einstein equations, traditionally, characteristic problems have been stated in the Bondi-Sachs form, whereas initial-value problems have been represented in the ADM form, both being looked upon as independent versions of the Einstein equations. Under the restriction of spherical symmetry, we provide an ADM version of the Einstein equations that functions as the initial-value representation of the Bondi-Sachs equations. The ADM version allows us to interpret the Bondi-Sachs variables precisely in terms of characteristic fields of the Cauchy problem. The Bondi-Sachs version thus leads us to a version of the Cauchy problem that is first order in time (with no need for reduction) and automatically well posed.

  6. Examining Interactions between Problem Posing and Problem Solving with Prospective Primary Teachers: A Case of Using Fractions

    ERIC Educational Resources Information Center

    Xie, Jinxia; Masingila, Joanna O.

    2017-01-01

    Existing studies have quantitatively evidenced the relatedness between problem posing and problem solving, as well as the magnitude of this relationship. However, the nature and features of this relationship need further qualitative exploration. This paper focuses on exploring the interactions, i.e., mutual effects and supports, between problem…

  7. An efficient regularization method for a large scale ill-posed geothermal problem

    NASA Astrophysics Data System (ADS)

    Berntsson, Fredrik; Lin, Chen; Xu, Tao; Wokiyi, Dennis

    2017-08-01

    The inverse geothermal problem consists of estimating the temperature distribution below the earth's surface using measurements on the surface. The problem is important since temperature governs a variety of geologic processes, including the generation of magmas and the deformation style of rocks. Since the thermal properties of rocks depend strongly on temperature the problem is non-linear. The problem is formulated as an ill-posed operator equation, where the righthand side is the heat-flux at the surface level. Since the problem is ill-posed regularization is needed. In this study we demonstrate that Tikhonov regularization can be implemented efficiently for solving the operator equation. The algorithm is based on having a code for solving a well-posed problem related to the above mentioned operator. The algorithm is designed in such a way that it can deal with both 2 D and 3 D calculations. Numerical results, for 2 D domains, show that the algorithm works well and the inverse problem can be solved accurately with a realistic noise level in the surface data.

  8. The World in a Tomato: Revisiting the Use of "Codes" in Freire's Problem-Posing Education.

    ERIC Educational Resources Information Center

    Barndt, Deborah

    1998-01-01

    Gives examples of the use of Freire's notion of codes or generative themes in problem-posing literacy education. Describes how these applications expand Freire's conceptions by involving students in code production, including multicultural perspectives, and rethinking codes as representations. (SK)

  9. Mathematical Problem Posing as a Measure of Curricular Effect on Students' Learning

    ERIC Educational Resources Information Center

    Cai, Jinfa; Moyer, John C.; Wang, Ning; Hwang, Stephen; Nie, Bikai; Garber, Tammy

    2013-01-01

    In this study, we used problem posing as a measure of the effect of middle-school curriculum on students' learning in high school. Students who had used a standards-based curriculum in middle school performed equally well or better in high school than students who had used more traditional curricula. The findings from this study not only show…

  10. Development of a Mobile Learning System Based on a Collaborative Problem-Posing Strategy

    ERIC Educational Resources Information Center

    Sung, Han-Yu; Hwang, Gwo-Jen; Chang, Ya-Chi

    2016-01-01

    In this study, a problem-posing strategy is proposed for supporting collaborative mobile learning activities. Accordingly, a mobile learning environment has been developed, and an experiment on a local culture course has been conducted to evaluate the effectiveness of the proposed approach. Three classes of an elementary school in southern Taiwan…

  11. An Error Analysis in Division Problems in Fractions Posed by Pre-Service Elementary Mathematics Teachers

    ERIC Educational Resources Information Center

    Isik, Cemalettin; Kar, Tugrul

    2012-01-01

    The present study aimed to make an error analysis in the problems posed by pre-service elementary mathematics teachers about fractional division operation. It was carried out with 64 pre-service teachers studying in their final year in the Department of Mathematics Teaching in an eastern university during the spring semester of academic year…

  12. The World in a Tomato: Revisiting the Use of "Codes" in Freire's Problem-Posing Education.

    ERIC Educational Resources Information Center

    Barndt, Deborah

    1998-01-01

    Gives examples of the use of Freire's notion of codes or generative themes in problem-posing literacy education. Describes how these applications expand Freire's conceptions by involving students in code production, including multicultural perspectives, and rethinking codes as representations. (SK)

  13. Development of a Mobile Learning System Based on a Collaborative Problem-Posing Strategy

    ERIC Educational Resources Information Center

    Sung, Han-Yu; Hwang, Gwo-Jen; Chang, Ya-Chi

    2016-01-01

    In this study, a problem-posing strategy is proposed for supporting collaborative mobile learning activities. Accordingly, a mobile learning environment has been developed, and an experiment on a local culture course has been conducted to evaluate the effectiveness of the proposed approach. Three classes of an elementary school in southern Taiwan…

  14. An efficient solution to the five-point relative pose problem.

    PubMed

    Nistér, David

    2004-06-01

    An efficient algorithmic solution to the classical five-point relative pose problem is presented. The problem is to find the possible solutions for relative camera pose between two calibrated views given five corresponding points. The algorithm consists of computing the coefficients of a tenth degree polynomial in closed form and, subsequently, finding its roots. It is the first algorithm well-suited for numerical implementation that also corresponds to the inherent complexity of the problem. We investigate the numerical precision of the algorithm. We also study its performance under noise in minimal as well as overdetermined cases. The performance is compared to that of the well-known 8 and 7-point methods and a 6-point scheme. The algorithm is used in a robust hypothesize-and-test framework to estimate structure and motion in real-time with low delay. The real-time system uses solely visual input and has been demonstrated at major conferences.

  15. A truncated generalized singular value decomposition algorithm for moving force identification with ill-posed problems

    NASA Astrophysics Data System (ADS)

    Chen, Zhen; Chan, Tommy H. T.

    2017-08-01

    This paper proposes a new methodology for moving force identification (MFI) from the responses of bridge deck. Based on the existing time domain method (TDM), the MFI problem eventually becomes solving the linear algebraic equation in the form Ax = b . The vector b is usually contaminated by an unknown error e generating from measurement error, which often called the vector e as ''noise''. With the ill-posed problems that exist in the inverse problem, the identification force would be sensitive to the noise e . The proposed truncated generalized singular value decomposition method (TGSVD) aims at obtaining an acceptable solution and making the noise to be less sensitive to perturbations with the ill-posed problems. The illustrated results show that the TGSVD has many advantages such as higher precision, better adaptability and noise immunity compared with TDM. In addition, choosing a proper regularization matrix L and a truncation parameter k are very useful to improve the identification accuracy and to solve ill-posed problems when it is used to identify the moving force on bridge.

  16. Combining different types of data for ill-posed geophysical/geodetic problems

    NASA Astrophysics Data System (ADS)

    Xu, P.

    2012-04-01

    Regularization is crucial to solve geophysical and geodetic ill-posed inverse problems. In practice, we may combine different types of data to solve such an ill-posed inverse problem; the accuracy of these different types of data may not be known precisely and should be modelled by a number of unknown variance components. Although the weighting factors, or equivalently the variance components, can significantly affect joint inversion results of geophysical ill-posed problems, they have been either assumed to be known or empirically chosen. No solid statistical foundation is available yet to correctly determine the weighting factors of different types of data in joint geophysical inversion. In this case, all regularization techniques may not be proper to apply, unless techniques of variance component estimation are directly implemented to determine the correct weighting factors for each type of data. In this paper, we will solve ill-posed inverse problems by simultaneously determining the regularization parameter and the weighting factors of different types of data, either by using the criteria of mean squared errors or the cross validation. First we analyze the biases of estimated variance components due to the regularization parameter and then propose bias-corrected variance component estimators. We simulate two examples: a purely mathematical integral equation of the first kind modified from the first example of Phillips (1962) and a typical geophysical example of downward continuation to recover the gravity anomalies on the surface of the Earth from satellite measurements. Based on the two simulated examples, we extensively investigate the MSE and the iterative GCV methods. The simulated results have shown that these methods work well to correctly recover the unknown variance components and determine the regularization parameter. In other words, our methods let data speak for themselves, decide the correct weighting factors of different types of geophysical data

  17. [Problems posed by the death of one fetus in a twin pregnancy].

    PubMed

    Dallay, D; Soumireu-Mourat, J

    1985-12-01

    Much recent works has highlighted the problems posed by the death of one fetus in utero during multiple pregnancy. This is a rare but serious accident which exposes the mother and the surviving fetus to the transfer of placentary and fetal thromboplastins or to the direct embolization of necrosed fragments of the placenta. Only fetal death occurring during the second and third terms of pregnancy is considered.

  18. Fast nonstationary preconditioned iterative methods for ill-posed problems, with application to image deblurring

    NASA Astrophysics Data System (ADS)

    Donatelli, Marco; Hanke, Martin

    2013-09-01

    We introduce a new iterative scheme for solving linear ill-posed problems, similar to nonstationary iterated Tikhonov regularization, but with an approximation of the underlying operator to be used for the Tikhonov equations. For image deblurring problems, such an approximation can be a discrete deconvolution that operates entirely in the Fourier domain. We provide a theoretical analysis of the new scheme, using regularization parameters that are chosen by a certain adaptive strategy. The numerical performance of this method turns out to be superior to state-of-the-art iterative methods, including the conjugate gradient iteration for the normal equation, with and without additional preconditioning.

  19. Quelques problemes poses a la grammaire casuelle (Some Problems Regarding Case Grammar)

    ERIC Educational Resources Information Center

    Fillmore, Charles J.

    1975-01-01

    Discusses problems related to case grammar theory, including: the organizations of a case grammar; determination of semantic roles; definition and hierarchy of cases; cause-effect relations; and formalization and notation. (Text is in French.) (AM)

  20. Quelques problemes poses a la grammaire casuelle (Some Problems Regarding Case Grammar)

    ERIC Educational Resources Information Center

    Fillmore, Charles J.

    1975-01-01

    Discusses problems related to case grammar theory, including: the organizations of a case grammar; determination of semantic roles; definition and hierarchy of cases; cause-effect relations; and formalization and notation. (Text is in French.) (AM)

  1. Problem-Posing, Problem-Solving and Persuasion in Biology Education.

    ERIC Educational Resources Information Center

    Peterson, Nils S.; Jungck, John R.

    1988-01-01

    Discusses the advantages of using content specific problem solving as a vehicle for undergraduate instruction in biology, and describes different software tools used to implement this model. The areas discussed include simulated laboratories, the construction of binary classification schemes using computer programs, and scientific writing using…

  2. Nonstationary iterated Tikhonov regularization for ill-posed problems in Banach spaces

    NASA Astrophysics Data System (ADS)

    Jin, Qinian; Stals, Linda

    2012-10-01

    Nonstationary iterated Tikhonov regularization is an efficient method for solving ill-posed problems in Hilbert spaces. However, this method may not produce good results in some situations since it tends to oversmooth solutions and hence destroy special features such as sparsity and discontinuity. By making use of duality mappings and Bregman distance, we propose an extension of this method to the Banach space setting and establish its convergence. We also present numerical simulations which indicate that the method in Banach space setting can produce better results.

  3. Uniqueness Results for Ill-Posed Characteristic Problems in Curved Space-Times

    NASA Astrophysics Data System (ADS)

    Ionescu, Alexandru D.; Klainerman, Sergiu

    2009-02-01

    We prove two uniqueness theorems concerning linear wave equations; the first theorem is in Minkowski space-times, while the second is in the domain of outer communication of a Kerr black hole. Both theorems concern ill-posed Cauchy problems on bifurcate, characteristic hypersurfaces. In the case of the Kerr space-time, the hypersurface is precisely the event horizon of the black hole. The uniqueness theorem in this case, based on two Carleman estimates, is intimately connected to our strategy to prove uniqueness of the Kerr black holes among smooth, stationary solutions of the Einstein-vacuum equations, as formulated in [14].

  4. A problem-posing approach to teaching the topic of radioactivity

    NASA Astrophysics Data System (ADS)

    Klaassen, C. W. J. M.

    1995-12-01

    This thesis highlights a problem-posing approach to science education. By this is meant an approach that explicitly aims at providing students with content-related motives for extending their existing conceptual resources, experiential base and belief system in a certain direction, such that a further development in that direction eventually leads to a proper understanding of science. An elaboration of that approach consists in designing, testing, improving, etc, concrete didactical structures. The eventual aim of the approach is a coherent, and by means of developmental research empirically supported, didactical structure that covers the whole of science education. The thesis also contains a few steps in the direction suggested by this programmatic view. It contains an illustration of the heuristic value of an articulation of a didactical structure in some main substructures, based on the work of van Hiele and ten Voorde. It further contains a discussion of some methodological aspects relating to the design and evaluation of a didactical structure, and of the role that a further developed version of Davidson's theory of interpretation could play in this respect. A detailed didactical structure of the topic of radioactivity is presented, evaluated and, on the basis of the evaluation, judged as `good enough.' Also the role of the teacher in a problem-posing approach is dis-cussed, and in particular the consequences for that role of giving students control over and responsibility for the progress of their learning process with respect to content.

  5. Ill-posed problem and regularization in reconstruction of radiobiological parameters from serial tumor imaging data

    NASA Astrophysics Data System (ADS)

    Chvetsov, Alevei V.; Sandison, George A.; Schwartz, Jeffrey L.; Rengan, Ramesh

    2015-11-01

    The main objective of this article is to improve the stability of reconstruction algorithms for estimation of radiobiological parameters using serial tumor imaging data acquired during radiation therapy. Serial images of tumor response to radiation therapy represent a complex summation of several exponential processes as treatment induced cell inactivation, tumor growth rates, and the rate of cell loss. Accurate assessment of treatment response would require separation of these processes because they define radiobiological determinants of treatment response and, correspondingly, tumor control probability. However, the estimation of radiobiological parameters using imaging data can be considered an inverse ill-posed problem because a sum of several exponentials would produce the Fredholm integral equation of the first kind which is ill posed. Therefore, the stability of reconstruction of radiobiological parameters presents a problem even for the simplest models of tumor response. To study stability of the parameter reconstruction problem, we used a set of serial CT imaging data for head and neck cancer and a simplest case of a two-level cell population model of tumor response. Inverse reconstruction was performed using a simulated annealing algorithm to minimize a least squared objective function. Results show that the reconstructed values of cell surviving fractions and cell doubling time exhibit significant nonphysical fluctuations if no stabilization algorithms are applied. However, after applying a stabilization algorithm based on variational regularization, the reconstruction produces statistical distributions for survival fractions and doubling time that are comparable to published in vitro data. This algorithm is an advance over our previous work where only cell surviving fractions were reconstructed. We conclude that variational regularization allows for an increase in the number of free parameters in our model which enables development of more

  6. Regularization of linear ill-posed problems by the augmented Lagrangian method and variational inequalities

    NASA Astrophysics Data System (ADS)

    Frick, K.; Grasmair, M.

    2012-10-01

    We study the application of the augmented Lagrangian method to the solution of linear ill-posed problems. Previously, linear convergence rates with respect to the Bregman distance have been derived under the classical assumption of a standard source condition. Using the method of variational inequalities, we extend these results in this paper to convergence rates of lower order, both for the case of an a priori parameter choice and an a posteriori choice based on Morozov’s discrepancy principle. In addition, our approach allows the derivation of convergence rates with respect to distance measures different from the Bregman distance. As a particular application, we consider sparsity promoting regularization, where we derive a range of convergence rates with respect to the norm under the assumption of restricted injectivity in conjunction with generalized source conditions of Hölder type.

  7. Multiscale analysis for ill-posed problems with semi-discrete Tikhonov regularization

    NASA Astrophysics Data System (ADS)

    Zhong, Min; Lu, Shuai; Cheng, Jin

    2012-06-01

    Using compactly supported radial basis functions of varying radii, Wendland has shown how a multiscale analysis can be applied to the approximation of Sobolev functions on a bounded domain, when the available data are discrete and noisy. Here, we examine the application of this analysis to the solution of linear moderately ill-posed problems using semi-discrete Tikhonov-Phillips regularization. As in Wendland’s work, the actual multiscale approximation is constructed by a sequence of residual corrections, where different support radii are employed to accommodate different scales. The convergence of the algorithm for noise-free data is given. Based on the Morozov discrepancy principle, a posteriori parameter choice rule and error estimates for the noisy data are derived. Two numerical examples are presented to illustrate the appropriateness of the proposed method.

  8. Calibrating corneal material model parameters using only inflation data: an ill-posed problem.

    PubMed

    Kok, S; Botha, N; Inglis, H M

    2014-12-01

    Goldmann applanation tonometry (GAT) is a method used to estimate the intraocular pressure by measuring the indentation resistance of the cornea. A popular approach to investigate the sensitivity of GAT results to material and geometry variations is to perform numerical modelling using the finite element method, for which a calibrated material model is required. These material models are typically calibrated using experimental inflation data by solving an inverse problem. In the inverse problem, the underlying material constitutive behaviour is inferred from the measured macroscopic response (chamber pressure versus apical displacement). In this study, a biomechanically motivated elastic fibre-reinforced corneal material model is chosen. The inverse problem of calibrating the corneal material model parameters using only experimental inflation data is demonstrated to be ill-posed, with small variations in the experimental data leading to large differences in the calibrated model parameters. This can result in different groups of researchers, calibrating their material model with the same inflation test data, drawing vastly different conclusions about the effect of material parameters on GAT results. It is further demonstrated that multiple loading scenarios, such as inflation as well as bending, would be required to reliably calibrate such a corneal material model.

  9. Degree of entanglement as a physically ill-posed problem: The case of entanglement with vacuum

    SciTech Connect

    Pawlowski, Marcin; Czachor, Marek

    2006-04-15

    We analyze an example of a photon in a superposition of different modes, and ask what is the degree of their entanglement with a vacuum. The problem turns out to be ill-posed since we do not know which representation of the algebra of canonical commutation relations (CCR) to choose for the field quantization. Once we make a choice, we can solve the question of entanglement unambiguously. So the difficulty is not with mathematics, but with physics of the problem. In order to make the discussion explicit we analyze from this perspective a popular argument based on a photon leaving a beam splitter and interacting with two two-level atoms. We first solve the problem algebraically in the Heisenberg picture, without any assumption about the form of representation of CCR. Then we take the {infinity}-representation and show in two ways that in two-mode states the modes are maximally entangled with the vacuum, but single-mode states are not entangled. Next we repeat the analysis in terms of the representation of CCR taken from Berezin's book and show that two-mode states do not involve the mode-vacuum entanglement. Finally, we switch to a family of reducible representations of CCR recently investigated in the context of field quantization, and show that the entanglement with the vacuum is present even for single-mode states. Still, the degree of entanglement here is difficult to estimate, mainly because there are N+2 subsystems, with N unspecified and large.

  10. High-School Students' Approaches to Solving Algebra Problems that Are Posed Symbolically: Results from an Interview Study

    ERIC Educational Resources Information Center

    Huntley, Mary Ann; Davis, Jon D.

    2008-01-01

    A cross-curricular structured-probe task-based clinical interview study with 44 pairs of third year high-school mathematics students, most of whom were high achieving, was conducted to investigate their approaches to a variety of algebra problems. This paper presents results from three problems that were posed in symbolic form. Two problems are…

  11. High-School Students' Approaches to Solving Algebra Problems that Are Posed Symbolically: Results from an Interview Study

    ERIC Educational Resources Information Center

    Huntley, Mary Ann; Davis, Jon D.

    2008-01-01

    A cross-curricular structured-probe task-based clinical interview study with 44 pairs of third year high-school mathematics students, most of whom were high achieving, was conducted to investigate their approaches to a variety of algebra problems. This paper presents results from three problems that were posed in symbolic form. Two problems are…

  12. Sparse deconvolution for the large-scale ill-posed inverse problem of impact force reconstruction

    NASA Astrophysics Data System (ADS)

    Qiao, Baijie; Zhang, Xingwu; Gao, Jiawei; Liu, Ruonan; Chen, Xuefeng

    2017-01-01

    Most previous regularization methods for solving the inverse problem of force reconstruction are to minimize the l2-norm of the desired force. However, these traditional regularization methods such as Tikhonov regularization and truncated singular value decomposition, commonly fail to solve the large-scale ill-posed inverse problem in moderate computational cost. In this paper, taking into account the sparse characteristic of impact force, the idea of sparse deconvolution is first introduced to the field of impact force reconstruction and a general sparse deconvolution model of impact force is constructed. Second, a novel impact force reconstruction method based on the primal-dual interior point method (PDIPM) is proposed to solve such a large-scale sparse deconvolution model, where minimizing the l2-norm is replaced by minimizing the l1-norm. Meanwhile, the preconditioned conjugate gradient algorithm is used to compute the search direction of PDIPM with high computational efficiency. Finally, two experiments including the small-scale or medium-scale single impact force reconstruction and the relatively large-scale consecutive impact force reconstruction are conducted on a composite wind turbine blade and a shell structure to illustrate the advantage of PDIPM. Compared with Tikhonov regularization, PDIPM is more efficient, accurate and robust whether in the single impact force reconstruction or in the consecutive impact force reconstruction.

  13. Mixed gradient-Tikhonov methods for solving nonlinear ill-posed problems in Banach spaces

    NASA Astrophysics Data System (ADS)

    Margotti, Fábio

    2016-12-01

    Tikhonov regularization is a very useful and widely used method for finding stable solutions of ill-posed problems. A good choice of the penalization functional as well as a careful selection of the topologies of the involved spaces is fundamental to the quality of the reconstructions. These choices can be combined with some a priori information about the solution in order to preserve desired characteristics like sparsity constraints for example. To prove convergence and stability properties of this method, one usually has to assume that a minimizer of the Tikhonov functional is known. In practical situations however, the exact computation of a minimizer is very difficult and even finding an approximation can be a very challenging and expensive task if the involved spaces have poor convexity or smoothness properties. In this paper we propose a method to attenuate this gap between theory and practice, applying a gradient-like method to a Tikhonov functional in order to approximate a minimizer. Using only available information, we explicitly calculate a maximal step-size which ensures a monotonically decreasing error. The resulting algorithm performs only finitely many steps and terminates using the discrepancy principle. In particular the knowledge of a minimizer or even its existence does not need to be assumed. Under standard assumptions, we prove convergence and stability results in relatively general Banach spaces, and subsequently, test its performance numerically, reconstructing conductivities with sparsely located inclusions and different kinds of noise in the 2D electrical impedance tomography.

  14. Ways of Thinking Associated with Mathematics Teachers' Problem Posing in the Context of Division of Fractions

    ERIC Educational Resources Information Center

    Koichu, Boris; Harel, Guershon; Manaster, Alfred

    2013-01-01

    Twenty-four mathematics teachers were asked to think aloud when posing a word problem whose solution could be found by computing 4/5 divided by 2/3. The data consisted of verbal protocols along with the written notes made by the subjects. The qualitative analysis of the data was focused on identifying the structures of the problems produced and…

  15. Ways of Thinking Associated with Mathematics Teachers' Problem Posing in the Context of Division of Fractions

    ERIC Educational Resources Information Center

    Koichu, Boris; Harel, Guershon; Manaster, Alfred

    2013-01-01

    Twenty-four mathematics teachers were asked to think aloud when posing a word problem whose solution could be found by computing 4/5 divided by 2/3. The data consisted of verbal protocols along with the written notes made by the subjects. The qualitative analysis of the data was focused on identifying the structures of the problems produced and…

  16. Engaging Pre-Service Middle-School Teacher-Education Students in Mathematical Problem Posing: Development of an Active Learning Framework

    ERIC Educational Resources Information Center

    Ellerton, Nerida F.

    2013-01-01

    Although official curriculum documents make cursory mention of the need for problem posing in school mathematics, problem posing rarely becomes part of the implemented or assessed curriculum. This paper provides examples of how problem posing can be made an integral part of mathematics teacher education programs. It is argued that such programs…

  17. Analysis of Problems Posed by Sixth-Grade Middle School Students for the Addition of Fractions in Terms of Semantic Structures

    ERIC Educational Resources Information Center

    Kar, Tugrul

    2015-01-01

    This study aimed to investigate how the semantic structures of problems posed by sixth-grade middle school students for the addition of fractions affect their problem-posing performance. The students were presented with symbolic operations involving the addition of fractions and asked to pose two different problems related to daily-life situations…

  18. Analysis of Problems Posed by Sixth-Grade Middle School Students for the Addition of Fractions in Terms of Semantic Structures

    ERIC Educational Resources Information Center

    Kar, Tugrul

    2015-01-01

    This study aimed to investigate how the semantic structures of problems posed by sixth-grade middle school students for the addition of fractions affect their problem-posing performance. The students were presented with symbolic operations involving the addition of fractions and asked to pose two different problems related to daily-life situations…

  19. Process-based Assignment-Setting Change for Support of Overcoming Bottlenecks in Learning by Problem-Posing in Arithmetic Word Problems

    NASA Astrophysics Data System (ADS)

    Supianto, A. A.; Hayashi, Y.; Hirashima, T.

    2017-02-01

    Problem-posing is well known as an effective activity to learn problem-solving methods. Monsakun is an interactive problem-posing learning environment to facilitate arithmetic word problems learning for one operation of addition and subtraction. The characteristic of Monsakun is problem-posing as sentence-integration that lets learners make a problem of three sentences. Monsakun provides learners with five or six sentences including dummies, which are designed through careful considerations by an expert teacher as a meaningful distraction to the learners in order to learn the structure of arithmetic word problems. The results of the practical use of Monsakun in elementary schools show that many learners have difficulties in arranging the proper answer at the high level of assignments. The analysis of the problem-posing process of such learners found that their misconception of arithmetic word problems causes impasses in their thinking and mislead them to use dummies. This study proposes a method of changing assignments as a support for overcoming bottlenecks of thinking. In Monsakun, the bottlenecks are often detected as a frequently repeated use of a specific dummy. If such dummy can be detected, it is the key factor to support learners to overcome their difficulty. This paper discusses how to detect the bottlenecks and to realize such support in learning by problem-posing.

  20. Problem-Posing as a Didactic Resource in Formal Mathematics Courses to Train Future Secondary School Mathematics Teachers

    ERIC Educational Resources Information Center

    Solórzano, Lorena Salazar

    2015-01-01

    Beginning university training programs must focus on different competencies for mathematics teachers, i.e., not only on solving problems, but also on posing them and analyzing the mathematical activity. This paper reports the results of an exploratory study conducted with future secondary school mathematics teachers on the introduction of…

  1. The Numerical Inversion of the Laplace Transform in Reproducing Kernel Hilbert Spaces for Ill-Posed Problems

    ERIC Educational Resources Information Center

    Iqbal, M.

    2002-01-01

    In this paper we have converted the Laplace transform into an integral equation of the first kind of convolution type, which is an ill-posed problem, and used a statistical regularization method to solve it. The method is applied to three examples. It gives a good approximation to the true solution and compares well with the method given by…

  2. The Numerical Inversion of the Laplace Transform in Reproducing Kernel Hilbert Spaces for Ill-Posed Problems

    ERIC Educational Resources Information Center

    Iqbal, M.

    2002-01-01

    In this paper we have converted the Laplace transform into an integral equation of the first kind of convolution type, which is an ill-posed problem, and used a statistical regularization method to solve it. The method is applied to three examples. It gives a good approximation to the true solution and compares well with the method given by…

  3. Solution to the SLAM Problem in Low Dynamic Environments Using a Pose Graph and an RGB-D Sensor

    PubMed Central

    Lee, Donghwa; Myung, Hyun

    2014-01-01

    In this study, we propose a solution to the simultaneous localization and mapping (SLAM) problem in low dynamic environments by using a pose graph and an RGB-D (red-green-blue depth) sensor. The low dynamic environments refer to situations in which the positions of objects change over long intervals. Therefore, in the low dynamic environments, robots have difficulty recognizing the repositioning of objects unlike in highly dynamic environments in which relatively fast-moving objects can be detected using a variety of moving object detection algorithms. The changes in the environments then cause groups of false loop closing when the same moved objects are observed for a while, which means that conventional SLAM algorithms produce incorrect results. To address this problem, we propose a novel SLAM method that handles low dynamic environments. The proposed method uses a pose graph structure and an RGB-D sensor. First, to prune the falsely grouped constraints efficiently, nodes of the graph, that represent robot poses, are grouped according to the grouping rules with noise covariances. Next, false constraints of the pose graph are pruned according to an error metric based on the grouped nodes. The pose graph structure is reoptimized after eliminating the false information, and the corrected localization and mapping results are obtained. The performance of the method was validated in real experiments using a mobile robot system. PMID:25019633

  4. Posing Complex Problems Requiring Multiplicative Thinking Prompts Students to Use Sophisticated Strategies and Build Mathematical Connections

    ERIC Educational Resources Information Center

    Downton, Ann; Sullivan, Peter

    2017-01-01

    While the general planning advice offered to mathematics teachers seems to be to start with simple examples and build complexity progressively, the research reported in this article is a contribution to the body of literature that argues the reverse. That is, posing of appropriately complex tasks may actually prompt the use of more sophisticated…

  5. A unified well-posed computational approach for the 2D Orr-Sommerfeld problem

    NASA Astrophysics Data System (ADS)

    Mehta, Prashant G.

    2004-09-01

    In this paper, we present a unified well-posed implicit formulation for nonlinear 2D Orr-Sommerfeld equation (OSE) enabling straightforward, efficient computation of travelling wave and steady solutions. We illustrate the ease and utility of our approach by computing classical travelling wave results of planar Poiseuille flows and novel steady solutions of the perturbed planar Couette flow, employing the path-following software AUTO.

  6. Well-Posed Stokes/Brinkman and Stokes/Darcy Problems for Coupled Fluid-Porous Viscous Flows

    NASA Astrophysics Data System (ADS)

    Angot, Philippe

    2010-09-01

    We present a well-posed model for the Stokes/Brinkman problem with a family of jump embedded boundary conditions (J.E.B.C.) on an immersed interface with weak regularity assumptions. It is issued from a general framework recently proposed for fictitious domain problems. Our model is based on algebraic transmission conditions combining the stress and velocity jumps on the interface Σ separating the fluid and porous domains. These conditions, well chosen to get the coercivity of the operator, are sufficiently general to get the usual immersed boundary conditions on Σ when fictitious domain methods are concerned: Stefan-like, Robin (Fourier), Neumann or Dirichlet… Moreover, the general framework allows to prove the global solvability of some models with physically relevant stress or velocity jump boundary conditions for the momentum transport at a fluid-porous interface. The Stokes/Brinkman problem with Ochoa-Tapia & Whitaker (1995) interface conditions and the Stokes/Darcy problem with Beavers & Joseph (1967) conditions are both proved to be well-posed by an asymptotic analysis. Up to our knowledge, only the Stokes/Darcy problem with Saffman (1971) approximate interface conditions was known to be well-posed.

  7. Analysis of problems posed by sixth-grade middle school students for the addition of fractions in terms of semantic structures

    NASA Astrophysics Data System (ADS)

    Kar, Tuğrul

    2015-08-01

    This study aimed to investigate how the semantic structures of problems posed by sixth-grade middle school students for the addition of fractions affect their problem-posing performance. The students were presented with symbolic operations involving the addition of fractions and asked to pose two different problems related to daily-life situations for each item, which could only be solved using the given operations. The problems posed were analyzed in terms of their semantic structures and conceptual validity. The results of the study showed that students who posed problems using the two different structures 'part-part-whole' and 'join' demonstrated higher performance in problem posing. The performance of the students using only one category - join or part-part-whole - was lower, with the latter being the lowest.

  8. C-type cytochromes: diverse structures and biogenesis systems pose evolutionary problems.

    PubMed Central

    Allen, James W A; Daltrop, Oliver; Stevens, Julie M; Ferguson, Stuart J

    2003-01-01

    C-type cytochromes are a structurally diverse group of haemoproteins, which are related by the occurrence of haem covalently attached to a polypeptide via two thioether bonds formed by the vinyl groups of haem and cysteine side chains in a CXXCH peptide motif. Remarkably, three different post-translational systems for forming these cytochromes have been identified. The evolution of both the proteins themselves and the biogenesis systems poses many questions to which answers are currently being sought. In this article we review the progress that has been made in understanding the need for covalent attachment of haem to proteins in cytochromes c and the complex systems involved in their formation. PMID:12594933

  9. The adult attachment interview: rating and classification problems posed by non-normative samples.

    PubMed

    Turton, P; McGauley, G; Marin-Avellan, L; Hughes, P

    2001-12-01

    Non-normative samples can pose major procedural and coding challenges to interviewers and raters of the Adult Attachment Interview (AAI). With reference to interview transcripts drawn from a population of personality disordered offenders detained in a high-security hospital, specific difficulties are identified and discussed. These difficulties have their roots in three separate but overlapping areas: extreme attachment-related experience; interviewees' psychological or psychiatric state; and factors relating to the context in which the interview is conducted. They raise questions about whether and when the use of the interview should be restricted, the rating rules elaborated and/or the rating system expanded. Suggestions are made as to how some of the difficulties might be addressed.

  10. Convergence analysis of a two-point gradient method for nonlinear ill-posed problems

    NASA Astrophysics Data System (ADS)

    Hubmer, Simon; Ramlau, Ronny

    2017-09-01

    We perform a convergence analysis of a two-point gradient method which is based on Landweber iteration and on Nesterov’s acceleration scheme. Additionally, we show the usefulness of this method via two numerical example problems based on a nonlinear Hammerstein operator and on the nonlinear inverse problem of single photon emission computed tomography.

  11. Is the forward problem of ground water hydrology always well posed?

    PubMed

    Valota, Giorgio; Giudici, Mauro; Parravicini, Guido; Ponzini, Giansilvio; Romano, Emanuele

    2002-01-01

    Complex aquifer systems are often modeled with quasi-three-dimensional models, which consider two-dimensional horizontal flow in the aquifers and one-dimensional vertical flow through aquitards. When the aquifer system consists of a phreatic aquifer and one or more semiconfined aquifers connected by aquitards, the discrete model consists of a nonlinear system of algebraic equations, because the transmissivity of the phreatic aquifer depends on the phreatic head. If the water extraction is very high, the phreatic aquifer can be depleted and the equations of the model must be modified accordingly. There are not simple and general criteria to state if the phreatic aquifer is depleted before solving the system of equations. Therefore, the iterative procedures (e.g., relaxation methods), used to find the solution to the forward problem, must handle these particular conditions and can suffer several problems of convergence. These problems can be caused by the choice of the initial head values or of the relaxation coefficient of the iterative algorithms; however, they can also be caused by the nonexistence or nonuniqueness of the solution to the system of nonlinear equations. The study of existence and uniqueness of the general problem is very difficult and, therefore, we consider a simplified problem, for which the discrete model can be handled analytically. The results of the numerical experiments show that the solution to the forward problem can be nonunique. Only for some cases it is possible to invoke physical arguments to eliminate tentative solutions.

  12. [Problems posed during surgical repair of a gunshot wound in the mandible].

    PubMed

    Roulaud, J P; Tournaire, J; Roux, R

    1975-09-01

    The authors present a case of a balistic lesion of the labio-mental region after attempted suicide. They expose the different procedures used for its repair and attempt to analyze the problems which arose from the therapeutic standpoint. They lay stress on the necessity to immobilize these mandibular fragments in good occlusion, as rapidly as possibly.

  13. Fast inference of ill-posed problems within a convex space

    NASA Astrophysics Data System (ADS)

    Fernandez-de-Cossio-Diaz, J.; Mulet, R.

    2016-07-01

    In multiple scientific and technological applications we face the problem of having low dimensional data to be justified by a linear model defined in a high dimensional parameter space. The difference in dimensionality makes the problem ill-defined: the model is consistent with the data for many values of its parameters. The objective is to find the probability distribution of parameter values consistent with the data, a problem that can be cast as the exploration of a high dimensional convex polytope. In this work we introduce a novel algorithm to solve this problem efficiently. It provides results that are statistically indistinguishable from currently used numerical techniques while its running time scales linearly with the system size. We show that the algorithm performs robustly in many abstract and practical applications. As working examples we simulate the effects of restricting reaction fluxes on the space of feasible phenotypes of a genome scale Escherichia coli metabolic network and infer the traffic flow between origin and destination nodes in a real communication network.

  14. Language and Culture in Conflict. Problem-Posing in the ESL Classroom.

    ERIC Educational Resources Information Center

    Wallerstein, Nina

    This book grew out of an actual experience developing and implementing a problem-solving process, using the Paulo Freire approach, for teaching English as a second language (ESL) adult students. This process implies a serious and long-term commitment to developing critical thinking skills. The first part of the book discusses who the students are,…

  15. Language and Culture in Conflict. Problem-Posing in the ESL Classroom.

    ERIC Educational Resources Information Center

    Wallerstein, Nina

    This book grew out of an actual experience developing and implementing a problem-solving process, using the Paulo Freire approach, for teaching English as a second language (ESL) adult students. This process implies a serious and long-term commitment to developing critical thinking skills. The first part of the book discusses who the students are,…

  16. The Development of Questioning as a Means of Framing Problems and Posing Challenges.

    ERIC Educational Resources Information Center

    Feigenbaum, Peter

    When a person encounters a problem, the character, form, and content of his or her response provides psychologists with useful and interesting information about processes of challenge and their relationship to intellectual development. In essence, challenge is a developing relationship that is defined on the one hand by objective factors (a person…

  17. Maternal physiological dysregulation while parenting poses risk for infant attachment disorganization and behavior problems.

    PubMed

    Leerkes, Esther M; Su, Jinni; Calkins, Susan D; O'Brien, Marion; Supple, Andrew J

    2017-02-01

    The extent to which indices of maternal physiological arousal (skin conductance augmentation) and regulation (vagal withdrawal) while parenting predict infant attachment disorganization and behavior problems directly or indirectly via maternal sensitivity was examined in a sample of 259 mothers and their infants. Two covariates, maternal self-reported emotional risk and Adult Attachment Interview attachment coherence were assessed prenatally. Mothers' physiological arousal and regulation were measured during parenting tasks when infants were 6 months old. Maternal sensitivity was observed during distress-eliciting tasks when infants were 6 and 14 months old, and an average sensitivity score was calculated. Attachment disorganization was observed during the Strange Situation when infants were 14 months old, and mothers reported on infants' behavior problems when infants were 27 months old. Over and above covariates, mothers' arousal and regulation while parenting interacted to predict infant attachment disorganization and behavior problems such that maternal arousal was associated with higher attachment disorganization and behavior problems when maternal regulation was low but not when maternal regulation was high. This effect was direct and not explained by maternal sensitivity. The results suggest that maternal physiological dysregulation while parenting places infants at risk for psychopathology.

  18. Analysis and Numerical Analysis of Some Properly and Improperly Posed Problems in Applied Mathematics

    DTIC Science & Technology

    1988-10-14

    In our recent work with Bandle ( "On the Existence and Nonexistence of Global Solutions to Reaction Diffusion Equations in Sectorial Domains" which... evolution equations . (2) Parameter identification problems. ’-" X! C 20 DISTRIBUTION/AVAILABILITY OF ABSTRACT 21 ABSTRACT SECURITY CLASSIFICATION 0...behavior of solutions of nonlinear evolution equations . We con- sidered certain scalar nonlinear hyperbolic and parabolic equations , and also

  19. The anatomical problem posed by brain complexity and size: a potential solution.

    PubMed

    DeFelipe, Javier

    2015-01-01

    Over the years the field of neuroanatomy has evolved considerably but unraveling the extraordinary structural and functional complexity of the brain seems to be an unattainable goal, partly due to the fact that it is only possible to obtain an imprecise connection matrix of the brain. The reasons why reaching such a goal appears almost impossible to date is discussed here, together with suggestions of how we could overcome this anatomical problem by establishing new methodologies to study the brain and by promoting interdisciplinary collaboration. Generating a realistic computational model seems to be the solution rather than attempting to fully reconstruct the whole brain or a particular brain region.

  20. A well-posed Cauchy problem for an evolution equation with coefficients of low regularity

    NASA Astrophysics Data System (ADS)

    Cicognani, Massimo; Colombini, Ferruccio

    In the hyperbolic Cauchy problem, the well-posedness in Sobolev spaces is strictly related to the modulus of continuity of the coefficients. This holds true for p-evolution equations with real characteristics (p=1 hyperbolic equations, p=2 vibrating plate and Schrödinger type models, …). We show that, for p⩾2, a lack of regularity in t can be balanced by a damping of the too fast oscillations as the space variable x→∞. This cannot happen in the hyperbolic case p=1 because of the finite speed of propagation.

  1. The anatomical problem posed by brain complexity and size: a potential solution

    PubMed Central

    DeFelipe, Javier

    2015-01-01

    Over the years the field of neuroanatomy has evolved considerably but unraveling the extraordinary structural and functional complexity of the brain seems to be an unattainable goal, partly due to the fact that it is only possible to obtain an imprecise connection matrix of the brain. The reasons why reaching such a goal appears almost impossible to date is discussed here, together with suggestions of how we could overcome this anatomical problem by establishing new methodologies to study the brain and by promoting interdisciplinary collaboration. Generating a realistic computational model seems to be the solution rather than attempting to fully reconstruct the whole brain or a particular brain region. PMID:26347617

  2. Solution to manufacturer`s hazardous waste poses problem for analyst

    SciTech Connect

    Wickham St. Germain, M.E.

    1997-12-31

    Manufacturers are finding alternative methods for rinsing parts and for cleaning equipment needed in process changes. By using alkaline detergents or polyglymes (i.e., polyethylene glycol), some manufacturers have eliminated or reduced the volume of solvents that they use. Therefore, the manufacturers have reduced the Resource and Recovery Act (RCRA) regulated waste from their facilities, and have reduced the cost of disposal of the waste. The manufacturing processes generate some foam, and the foam is not seen as a problem by the manufacturers as long as the foam can be controlled and rinsed away. Unfortunately, collection of samples with zero headspace is nearly impossible when several inches of foam exist above the effluent. In addition, the required analytical techniques propagate additional foaming by sparging inert gas through the sample or by vigorous shaking. As more manufacturers switch to alkaline detergents or polyglymes, analysts will more frequently face a severe foaming problem which may contaminate analytical instruments or increase the extraction time. This paper will present a brief summary of methods to reduce foaming in the analytical laboratory, a recent literature review on antifoam agents/defoamers, and possible application of defoamers to analytical techniques.

  3. Eigen analysis of tree-ring records: part 2, posing the eigen problem

    NASA Astrophysics Data System (ADS)

    Yang, Bao; Sonechkin, Dmitry M.; Datsenko, Nina M.; Ivashchenko, Nadezda N.; Liu, Jingjing; Qin, Chun

    2012-01-01

    The technique of expanding meteorological fields on eigenvectors of the field covariation matrix is popular. In this paper, we propose for the first time to use a mathematically similar technique to solve the main problem of dendrochronology: classifying variations in tree-ring records as either age- and microenvironment-dependent or climate-induced. Applying this technique to a sample of very long-lived Qilian junipers ( Sabina przewalskii Kom.) from the Dulan region in western China, we demonstrate that the ring-width variations projected on the first eigenvector are age-dependent, but those projected on several of the first subsequent vectors are mainly climate-induced. In particular, the second and third projections capture multi-centennial climatic variations, and the variations projected on the fourth through seventh eigenvectors show periodic variations that are probably induced by the 178-year solar cycle. The projections on the smallest eigenvectors seem to be negligible.

  4. Problem posing and cultural tailoring: developing an HIV/AIDS health literacy toolkit with the African American community.

    PubMed

    Rikard, R V; Thompson, Maxine S; Head, Rachel; McNeil, Carlotta; White, Caressa

    2012-09-01

    The rate of HIV infection among African Americans is disproportionately higher than for other racial groups in the United States. Previous research suggests that low level of health literacy (HL) is an underlying factor to explain racial disparities in the prevalence and incidence of HIV/AIDS. The present research describes a community and university project to develop a culturally tailored HIV/AIDS HL toolkit in the African American community. Paulo Freire's pedagogical philosophy and problem-posing methodology served as the guiding framework throughout the development process. Developing the HIV/AIDS HL toolkit occurred in a two-stage process. In Stage 1, a nonprofit organization and research team established a collaborative partnership to develop a culturally tailored HIV/AIDS HL toolkit. In Stage 2, African American community members participated in focus groups conducted as Freirian cultural circles to further refine the HIV/AIDS HL toolkit. In both stages, problem posing engaged participants' knowledge, experiences, and concerns to evaluate a working draft toolkit. The discussion and implications highlight how Freire's pedagogical philosophy and methodology enhances the development of culturally tailored health information.

  5. Estimating Atmospheric Fe Deposition to the Remote Ocean: the Problems Posed by Solubility Control

    NASA Astrophysics Data System (ADS)

    Measures, C. I.

    2001-12-01

    John Edmond's scientific career was dedicated to exploiting the tracer properties of chemical distributions in the ocean and using these to further our understanding of Earth and ocean processes. He realised that since chemical distributions result from geological, physical and biological processes, their interpretation is a powerful tool that can be used to explain many disparate elements of Earth sciences. In addition, the natural integrating power of chemical distributions over long time scales provides a unique opportunity to temporally average high frequency processes. The ability to apply these tools to current problems requires development and application of methodology that can be used over large temporal and spatial scales. John helped foster the development of real time trace element determinations at sea. A particularly good example of the results that this work has produced is using surface water trace element distributions to develop an understanding of the role that atmospheric deposition processes play in biogeochemical cycles. The partial dissolution of atmospheric dust in surface waters leaves a chemical wake that can be used to determine the magnitude and locus of atmospheric deposition events. In particular, dissolved aluminium concentrations in surface waters appear to be largely driven by atmospheric processes. Thus, modeling of the distribution of this element is being used to develop an understanding of atmospheric deposition processes in oceanic regions that are not suitable for direct sampling. When used in conjunction with surface water distributions of iron, the role of atmospheric deposition for this biologically important element can also be studied. However, the few existing data sets indicate that current models of iron deposition to the surface ocean, which simply apply a fixed fractional solubility of iron in dust, are unlikely to succeed, since the absolute solubility of iron limits the addition of this element to the surface ocean

  6. Math Club Problem Posing

    ERIC Educational Resources Information Center

    Simic-Muller, Ksenija; Turner, Erin E.; Varley, Maura C.

    2009-01-01

    This article describes an after-school mathematics program for Latino students. The program focuses on field trips to explore the mathematical practices of the community's businesses. The authors elaborate the project's general structure and illustrate the principles that guided the program. (Contains 3 tables.)

  7. ["Veille sanitaire": tools, functions, process of healthcare monitoring in France].

    PubMed

    Eilstein, D; Salines, G; Desenclos, J-C

    2012-10-01

    In France, the term "veille sanitaire" is widely used to designate healthcare monitoring. It contains, however, a set of concepts that are not shared equally by the entire scientific community. The same is true for activities that are part of it, even if some (surveillance for example) are already well defined. Concepts such as "observation", "vigilance", "alert" for example are not always clear. Furthermore, the use of these words in everyday language maintains this ambiguity. Thus, it seemed necessary to recall these definitions as already used in the literature or legislation texts and to make alternative suggestions. This formalization cannot be carried out without thinking about the structure of "veille sanitaire" and its components. Proposals are provided bringing out concepts of formated "veille" (monitoring) and non-formatted "veille" (monitoring). Definitions, functions, (methods and tools, processes) of these two components are outlined here as well as the cooperative relationship they sustain. The authors have attempted to provide the scientific community with a reference framework useful for exchanging information to promote research and methodological development dedicated to this public health application of epidemiology. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  8. An iterative virtual projection method to improve the reconstruction performance for ill-posed emission tomographic problems

    NASA Astrophysics Data System (ADS)

    Liu, Hua-Wei; Zheng, Shu; Zhou, Huai-Chun

    2015-10-01

    In order to improve the reconstruction performance for ill-posed emission tomographic problems with limited projections, a generalized interpolation method is proposed in this paper, in which the virtual lines of projection are fabricated from, but not linearly dependent on, the measured projections. The method is called the virtual projection (VP) method. Also, an iterative correction method for the integral lengths is proposed to reduce the error brought about by the virtual lines of projection. The combination of the two methods is called the iterative virtual projection (IVP) method. Based on a scheme of equilateral triangle plane meshes and a six asymmetrically arranged detection system, numerical simulations and experimental verification are conducted. Simulation results obtained by using a non-negative linear least squares method, without any other constraints or regularization, demonstrate that the VP method can gradually reduce the reconstruction error and converges to the desired one by fabricating additional effective projections. When the mean square deviation of normal error superimposed on the simulated measured projections is smaller than 0.03, i.e., the signal-to-noise ratio (SNR) for the measured projections is higher than 30.4, the IVP method can further reduce the reconstruction error reached by the VP method apparently. In addition, as the regularization matrix in the Tikhonov regularization method is updated by an iterative correction process similar to the IVP method presented in this paper, or the Tikhonov regularization method is used in the IVP method, good improvement is achieved. Project supported by the China National Funds for Distinguished Young Scientists of National Natural Science Foundation of China (Grant No. 51025622), the National Natural Science Foundation of China (Grant No. 51406095), and the 100 Top Talents Program of Tsinghua University, Beijing, China (2011).

  9. The present global financial and economic crisis poses an additional risk factor for mental health problems on the employees.

    PubMed

    Avčin, Bojana Avguštin; Kučina, Andrea Užmah; Sarotar, Brigita Novak; Radovanović, Mirjana; Plesničar, Blanka Kores

    2011-09-01

    The global financial and economic crisis starting in 2007 led to a deterioration of several socio-economic determinants of mental health. The aim of this cross-sectional study was to examine the impact of the present economic crisis on the depression and anxiety levels of the employed in the private and public sector in Slovenia. Altogether 1592 employees completed an internet based self-reported questionnaire. Data about perceived impact of the economic crisis, several socio-demographic, socioeconomic, and health parameters were collected. Depression symptoms were assessed by the Center for Epidemiological Studies-Depression Scale and anxiety symptoms by the Spielberger State-Inventory. Regression models were used 1) to explore the associations of the economic crisis with the level of depression and anxiety symptoms while controlling for some sociodemographic and work characteristic variables, and 2) to understand the relationship between some potentially important socioeconomic variables and the perception of the economic crisis. Depressive and anxiety scores were significantly increased among 590 (46.6%) employees being affected by the economic crisis. The level of depressive symptoms was significantly associated with perceived impact by the crisis, recent sick leave, reported injuries sustained at work, benzodiazepine and analgesic use, the lack of emotional support, and trust in crisis telephone lines. The level of anxiety symptoms yielded the robust association with the level of depression symptoms, reported injuries sustained on the way to work and education. The economic crisis poses an additional risk factor for mental health problems which clinicians should internalize and become more aware of them. Symptoms of depression and anxiety can be masked in high-utilizers of medical care with physical complaints or psychoactive drug use.

  10. The Effect of Problem Posing Oriented Analyses-II Course on the Attitudes toward Mathematics and Mathematics Self-Efficacy of Elementary Prospective Mathematics Teachers

    ERIC Educational Resources Information Center

    Akay, Hayri; Boz, Nihat

    2010-01-01

    Research on mathematics teaching and learning has recently focused on affective variables, which were found to play an essential role that influences behaviour and learning. Despite its importance, problem posing has not yet received the attention it warrants from the mathematics education community. Perceived self-efficacy beliefs have been found…

  11. On parameter choice in the regularization of ill-posed problems with rough estimate of the noise level of the data

    NASA Astrophysics Data System (ADS)

    Hämarik, U.; Kangro, U.; Palm, R.; Raus, T.

    2012-09-01

    We consider linear ill-posed problems in Hilbert space with noisy data. The noise level may be given exactly or approximately or there may be no information about the noise level. We regularize the problem using the Landweber method, the Tikhonov method or the iterated or extrapolated version of the Tikhonov method. For all three cases of noise information we propose rules for the choice of the regularization parameter and give recommendations for preferences of rules depending on the accuracy of noise level information. The main attention is paid for the case if the noise level is under-or overestimated.

  12. Rethinking Pedagogy for Second-Order Differential Equations: A Simplified Approach to Understanding Well-Posed Problems

    ERIC Educational Resources Information Center

    Tisdell, Christopher C.

    2017-01-01

    Knowing an equation has a unique solution is important from both a modelling and theoretical point of view. For over 70 years, the approach to learning and teaching "well posedness" of initial value problems (IVPs) for second- and higher-order ordinary differential equations has involved transforming the problem and its analysis to a…

  13. Revisiting mathematical problem solving and posing in the digital era: toward pedagogically sound uses of modern technology

    NASA Astrophysics Data System (ADS)

    Abramovich, S.

    2014-10-01

    The availability of sophisticated computer programs such as Wolfram Alpha has made many problems found in the secondary mathematics curriculum somewhat obsolete for they can be easily solved by the software. Against this background, an interplay between the power of a modern tool of technology and educational constraints it presents is discussed. Using topics from algebra (equations) and elementary number theory (summation of powers of integers), the paper suggests ways of developing problems that are both technology-immune and technology-enabled in the sense that whereas software can facilitate problem solving, its direct application is not sufficient for finding an answer. Stemming from the author's work with secondary mathematics teacher candidates, this paper highlights the appropriate use of technology as support system for multiple ways of knowing and knowledge construction in the modern classroom.

  14. The "Kind of Problem Cities Pose": Jane Jacobs at the Intersection of Philosophy, Pedagogy, and Urban Theory

    ERIC Educational Resources Information Center

    Fraser, Benjamin

    2009-01-01

    The matter of cities is, as urban critic Jane Jacobs argued, a complex problem akin to the life sciences. As a rich tradition of philosophical and geographical thought has suggested (Bergson, Lefebvre, and Harvey), the city is not a thing but a process. In order to reconcile process methodology and pedagogy, this essay explores six key ideas…

  15. The "Kind of Problem Cities Pose": Jane Jacobs at the Intersection of Philosophy, Pedagogy, and Urban Theory

    ERIC Educational Resources Information Center

    Fraser, Benjamin

    2009-01-01

    The matter of cities is, as urban critic Jane Jacobs argued, a complex problem akin to the life sciences. As a rich tradition of philosophical and geographical thought has suggested (Bergson, Lefebvre, and Harvey), the city is not a thing but a process. In order to reconcile process methodology and pedagogy, this essay explores six key ideas…

  16. Revisiting Mathematical Problem Solving and Posing in the Digital Era: Toward Pedagogically Sound Uses of Modern Technology

    ERIC Educational Resources Information Center

    Abramovich, S.

    2014-01-01

    The availability of sophisticated computer programs such as "Wolfram Alpha" has made many problems found in the secondary mathematics curriculum somewhat obsolete for they can be easily solved by the software. Against this background, an interplay between the power of a modern tool of technology and educational constraints it presents is…

  17. Revisiting Mathematical Problem Solving and Posing in the Digital Era: Toward Pedagogically Sound Uses of Modern Technology

    ERIC Educational Resources Information Center

    Abramovich, S.

    2014-01-01

    The availability of sophisticated computer programs such as "Wolfram Alpha" has made many problems found in the secondary mathematics curriculum somewhat obsolete for they can be easily solved by the software. Against this background, an interplay between the power of a modern tool of technology and educational constraints it presents is…

  18. Recycled Water Poses Disinfectant Problem

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1973

    1973-01-01

    Discusses the possible health hazards resulting from released nucleic acid of inactivated viruses, chlorinated nonliving organic molecules, and overestimated reliability of waste treatment standards. Suggests the recycle system use a dual disinfectant such as chlorine and ozone in water treatment. (CC)

  19. Recycled Water Poses Disinfectant Problem

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1973

    1973-01-01

    Discusses the possible health hazards resulting from released nucleic acid of inactivated viruses, chlorinated nonliving organic molecules, and overestimated reliability of waste treatment standards. Suggests the recycle system use a dual disinfectant such as chlorine and ozone in water treatment. (CC)

  20. Preconditioner and convergence study for the Quantum Computer Aided Design (QCAD) nonlinear poisson problem posed on the Ottawa Flat 270 design geometry.

    SciTech Connect

    Kalashnikova, Irina

    2012-05-01

    A numerical study aimed to evaluate different preconditioners within the Trilinos Ifpack and ML packages for the Quantum Computer Aided Design (QCAD) non-linear Poisson problem implemented within the Albany code base and posed on the Ottawa Flat 270 design geometry is performed. This study led to some new development of Albany that allows the user to select an ML preconditioner with Zoltan repartitioning based on nodal coordinates, which is summarized. Convergence of the numerical solutions computed within the QCAD computational suite with successive mesh refinement is examined in two metrics, the mean value of the solution (an L{sup 1} norm) and the field integral of the solution (L{sup 2} norm).

  1. An ill-posed problem for the Black-Scholes equation for a profitable forecast of prices of stock options on real market data

    NASA Astrophysics Data System (ADS)

    Klibanov, Michael V.; Kuzhuget, Andrey V.; Golubnichiy, Kirill V.

    2016-01-01

    A new empirical mathematical model for the Black-Scholes equation is proposed to forecast option prices. This model includes new interval for the price of the underlying stock, new initial and new boundary conditions. Conventional notions of maturity time and strike prices are not used. The Black-Scholes equation is solved as a parabolic equation with the reversed time, which is an ill-posed problem. Thus, a regularization method is used to solve it. To verify the validity of our model, real market data for 368 randomly selected liquid options are used. A new trading strategy is proposed. Our results indicates that our method is profitable on those options. Furthermore, it is shown that the performance of two simple extrapolation-based techniques is much worse. We conjecture that our method might lead to significant profits of those financial insitutions which trade large amounts of options. We caution, however, that further studies are necessary to verify this conjecture.

  2. SU-E-T-398: Evaluation of Radiobiological Parameters Using Serial Tumor Imaging During Radiotherapy as An Inverse Ill-Posed Problem

    SciTech Connect

    Chvetsov, A; Sandison, G; Schwartz, J; Rengan, R

    2015-06-15

    Purpose: Combination of serial tumor imaging with radiobiological modeling can provide more accurate information on the nature of treatment response and what underlies resistance. The purpose of this article is to improve the algorithms related to imaging-based radiobilogical modeling of tumor response. Methods: Serial imaging of tumor response to radiation therapy represents a sum of tumor cell sensitivity, tumor growth rates, and the rate of cell loss which are not separated explicitly. Accurate treatment response assessment would require separation of these radiobiological determinants of treatment response because they define tumor control probability. We show that the problem of reconstruction of radiobiological parameters from serial imaging data can be considered as inverse ill-posed problem described by the Fredholm integral equation of the first kind because it is governed by a sum of several exponential processes. Therefore, the parameter reconstruction can be solved using regularization methods. Results: To study the reconstruction problem, we used a set of serial CT imaging data for the head and neck cancer and a two-level cell population model of tumor response which separates the entire tumor cell population in two subpopulations of viable and lethally damage cells. The reconstruction was done using a least squared objective function and a simulated annealing algorithm. Using in vitro data for radiobiological parameters as reference data, we shown that the reconstructed values of cell surviving fractions and potential doubling time exhibit non-physical fluctuations if no stabilization algorithms are applied. The variational regularization allowed us to obtain statistical distribution for cell surviving fractions and cell number doubling times comparable to in vitro data. Conclusion: Our results indicate that using variational regularization can increase the number of free parameters in the model and open the way to development of more advanced

  3. Human pose co-estimation and applications.

    PubMed

    Eichner, Marcin; Ferrari, Vittorio

    2012-11-01

    Most existing techniques for articulated Human Pose Estimation (HPE)consider each person independently. Here we tackle the problem in a new setting,coined Human Pose Coestimation (PCE), where multiple people are in a common,but unknown pose. The task of PCE is to estimate their poses jointly and toproduce prototypes characterizing the shared pose. Since the poses of the individual people should be similar to the prototype, PCE has less freedom compared to estimating each pose independently, which simplifies the problem.We demonstrate our PCE technique on two applications. The first is estimating the pose of people performing the same activity synchronously, such as during aerobics, cheerleading, and dancing in a group. We show that PCE improves pose estimation accuracy over estimating each person independently. The second application is learning prototype poses characterizing a pose class directly from an image search engine queried by the class name (e.g., “lotus pose”). We show that PCE leads to better pose estimation in such images, and it learns meaningful prototypes which can be used as priors for pose estimation in novel images.

  4. Posing Einstein's Question: Questioning Einstein's Pose.

    ERIC Educational Resources Information Center

    Topper, David; Vincent, Dwight E.

    2000-01-01

    Discusses the events surrounding a famous picture of Albert Einstein in which he poses near a blackboard containing a tensor form of his 10 field equations for pure gravity with a question mark after it. Speculates as to the content of Einstein's lecture and the questions he might have had about the equation. (Contains over 30 references.) (WRM)

  5. Posing Einstein's Question: Questioning Einstein's Pose.

    ERIC Educational Resources Information Center

    Topper, David; Vincent, Dwight E.

    2000-01-01

    Discusses the events surrounding a famous picture of Albert Einstein in which he poses near a blackboard containing a tensor form of his 10 field equations for pure gravity with a question mark after it. Speculates as to the content of Einstein's lecture and the questions he might have had about the equation. (Contains over 30 references.) (WRM)

  6. Pose and motion from contact

    SciTech Connect

    Jia, Y.B.; Erdmann, M.

    1999-05-01

    In the absence of vision, grasping an object often relies on tactile feedback from the fingertips. As the finger pushes the object, the fingertip can feel the contact point move. If the object is known in advance, from this motion the finger may infer the location of the contact point on the object, and thereby, the object pose. This paper primarily investigates the problem of determining the pose (orientation and position) and motion (velocity and angular velocity) of a planar object with known geometry from such contact motion generated by pushing. A dynamic analysis of pushing yields a nonlinear system that relates through contact the object pose and motion to the finger motion. The contact motion on the fingertip thus encodes certain information about the object pose. Nonlinear observability theory is employed to show that such information is sufficient for the finger to observe not only the pose, but also the motion of the object. Therefore, a sensing strategy can be realized as an observer of the nonlinear dynamic system. Two observers are subsequently introduced. The first observer, based on the work of Gautheir, Hammouri, and Othman (1992), has its gain determined by the solution of a Lyapunov-like equation; it can be activated at any time instant during a push. The second observer, based on Newton`s method, solves for the initial (motionless) object pose from three intermediate contact points during a push. Under the Coulomb-friction model, the paper deals with support friction in the plane and/or contact friction between the finger and the object. Extensive simulations have been done to demonstrate the feasibility of the two observers. Preliminary experiments (with an Adept robot) have also been conducted. A contact sensor has been implemented using strain gauges.

  7. [Report of adverse events related to treatments to Institute de Veille sanitaire].

    PubMed

    Maingon, P; Simmon-Tellier, S

    2007-11-01

    The code de santé publique imposes to all health professionals an obligation to declare serious and undesirable events following cares applied during treatment investigations or prevention actions. An experimentation has been installed under the responsibility of the Institut de Veille sanitaire further to the 9 August 2004 bill. It aims to define how to declare undesirable adverse events to test its feasibility, its efficiency and to identify the necessary conditions to widespread its modalities. The field of these experimentations concerns all health professionals, working in public hospital or in private practice. The definition of undesirable adverse events should be clarified. Different ways to declare these events will be discussed with SFRO (Société française de radiothérapie oncologique) to improve the current management of incidents and adverse events.

  8. Phase unwrapping as an ill-posed problem: performance comparison between a neural-network-based approach and a stochastic search method

    NASA Astrophysics Data System (ADS)

    Chiaradia, Maria T.; Guerriero, Luciano; Refice, Alberto; Pasquariello, Guido; Satalino, Giuseppe; Stramaglia, Sebastiano

    1998-10-01

    2D phase unwrapping, a problem common to signal processing, optics, and interferometric radar topographic applications, consists in retrieving an absolute phase field from principal, noisy measurements. In this paper, we analyze the application of neural networks to this complex mathematical problem, formulating it as a learning-by-examples strategy, by training a multilayer perceptron to associate a proper correction pattern to the principal phase gradient configuration on local window. In spite of the high dimensionality of this problem the proposed MLP, trained on examples from simulated phase surfaces, shows to be able to correctly remove more than half the original number of pointlike inconsistencies on real noisy interferograms. Better efficiencies could be achieved by enlarging the processing window size, so as to exploit a greater amount of information. By pushing further this change of perspective, one passes from a local to a global point of view; problems of this kind are more effectively solved, rather than through learning strategies, by minimization procedures, for which we prose a powerful algorithm, based on a stochastic approach.

  9. Potential Energy Sources Pose Mining Problem

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1974

    1974-01-01

    Summarizes the discussions of a Division of Industrial and Engineering Chemistry symposium on solids handling for synthetic fuels production. Included is a description of technical difficulties with the use of coal seams and deposits of oil shale and oil sand as potential sources of fuel. (CC)

  10. [Therapeutic problems posed by various angiodysplasias].

    PubMed

    Maraval, M

    1980-01-01

    The clinical and anatomical aspects of the angiodysplasias are multiple and numerous classifications have been proposed. After review of a more simple classification put forward by Natali and Merland based on the contribution of superselective arteriography, consideration is given to a therapeutic approach for each angiodysplasia. Whereas for a long time the only therapeutic alternatives have been between surgery and no surgery, improved arteriographic understanding of these lesions has now permitted improved treatment, by surgery or by embolization or by the combination of the two methods. Finally the fields of the pure arterial dysplasias and the rares phacomatoses are considered, with a therapeutic scheme in each case.

  11. Contact Zones, Problem Posing and Critical Consciousness

    ERIC Educational Resources Information Center

    Patel, Lisa

    2012-01-01

    In this article, I share the shape and findings of a participatory action research project with newcomer youths on the contours of status in society. This project was nested in a professional internship experience for newcomer youth, and this experience provided the context in which we explored how privilege and status are afforded in American…

  12. Potential Energy Sources Pose Mining Problem

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1974

    1974-01-01

    Summarizes the discussions of a Division of Industrial and Engineering Chemistry symposium on solids handling for synthetic fuels production. Included is a description of technical difficulties with the use of coal seams and deposits of oil shale and oil sand as potential sources of fuel. (CC)

  13. Contact Zones, Problem Posing and Critical Consciousness

    ERIC Educational Resources Information Center

    Patel, Lisa

    2012-01-01

    In this article, I share the shape and findings of a participatory action research project with newcomer youths on the contours of status in society. This project was nested in a professional internship experience for newcomer youth, and this experience provided the context in which we explored how privilege and status are afforded in American…

  14. Electronic materials pose challenges

    SciTech Connect

    Frezzo, D.C.

    1986-04-01

    To prove that the Strategic Defense Initiative (SDI) is technically feasible, several demanding scientific and engineering criteria must be met. Electronic materials processing and electronics reliability are the challenging areas where it is necessary to demonstrate that SDI would be effective, survivable, and cost-effective. The rad-hardened ICs which enable sensors to see and which are critical to the surveillance satellites demonstrate the complexity of the problem. A long-term interest in SDI research will drive much of the world's technical development for decades, and indirectly affect the professional roles of scientists and engineers, who have both a social and technical responsibility to contribute to the debate.

  15. Factoring Algebraic Error for Relative Pose Estimation

    SciTech Connect

    Lindstrom, P; Duchaineau, M

    2009-03-09

    We address the problem of estimating the relative pose, i.e. translation and rotation, of two calibrated cameras from image point correspondences. Our approach is to factor the nonlinear algebraic pose error functional into translational and rotational components, and to optimize translation and rotation independently. This factorization admits subproblems that can be solved using direct methods with practical guarantees on global optimality. That is, for a given translation, the corresponding optimal rotation can directly be determined, and vice versa. We show that these subproblems are equivalent to computing the least eigenvector of second- and fourth-order symmetric tensors. When neither translation or rotation is known, alternating translation and rotation optimization leads to a simple, efficient, and robust algorithm for pose estimation that improves on the well-known 5- and 8-point methods.

  16. Accurate pose estimation for forensic identification

    NASA Astrophysics Data System (ADS)

    Merckx, Gert; Hermans, Jeroen; Vandermeulen, Dirk

    2010-04-01

    In forensic authentication, one aims to identify the perpetrator among a series of suspects or distractors. A fundamental problem in any recognition system that aims for identification of subjects in a natural scene is the lack of constrains on viewing and imaging conditions. In forensic applications, identification proves even more challenging, since most surveillance footage is of abysmal quality. In this context, robust methods for pose estimation are paramount. In this paper we will therefore present a new pose estimation strategy for very low quality footage. Our approach uses 3D-2D registration of a textured 3D face model with the surveillance image to obtain accurate far field pose alignment. Starting from an inaccurate initial estimate, the technique uses novel similarity measures based on the monogenic signal to guide a pose optimization process. We will illustrate the descriptive strength of the introduced similarity measures by using them directly as a recognition metric. Through validation, using both real and synthetic surveillance footage, our pose estimation method is shown to be accurate, and robust to lighting changes and image degradation.

  17. Human pose tracking from monocular video by traversing an image motion mapped body pose manifold

    NASA Astrophysics Data System (ADS)

    Basu, Saurav; Poulin, Joshua; Acton, Scott T.

    2010-01-01

    Tracking human pose from monocular video sequences is a challenging problem due to the large number of independent parameters affecting image appearance and nonlinear relationships between generating parameters and the resultant images. Unlike the current practice of fitting interpolation functions to point correspondences between underlying pose parameters and image appearance, we exploit the relationship between pose parameters and image motion flow vectors in a physically meaningful way. Change in image appearance due to pose change is realized as navigating a low dimensional submanifold of the infinite dimensional Lie group of diffeomorphisms of the two dimensional sphere S2. For small changes in pose, image motion flow vectors lie on the tangent space of the submanifold. Any observed image motion flow vector field is decomposed into the basis motion vector flow fields on the tangent space and combination weights are used to update corresponding pose changes in the different dimensions of the pose parameter space. Image motion flow vectors are largely invariant to style changes in experiments with synthetic and real data where the subjects exhibit variation in appearance and clothing. The experiments demonstrate the robustness of our method (within +/-4° of ground truth) to style variance.

  18. Direct solution to the minimal generalized pose.

    PubMed

    Miraldo, Pedro; Araujo, Helder

    2015-03-01

    Pose estimation is a relevant problem for imaging systems whose applications range from augmented reality to robotics. In this paper we propose a novel solution for the minimal pose problem, within the framework of generalized camera models and using a planar homography. Within this framework and considering only the geometric elements of the generalized camera models, an imaging system can be modeled by a set of mappings associating image pixels to 3-D straight lines. This mapping is defined in a 3-D world coordinate system. Pose estimation performs the computation of the rigid transformation between the original 3-D world coordinate system and the one in which the camera was calibrated. Using synthetic data, we compare the proposed minimal-based method with the state-of-the-art methods in terms of numerical errors, number of solutions and processing time. From the experiments, we conclude that the proposed method performs better, especially because there is a smaller variation in numerical errors, while results are similar in terms of number of solutions and computation time. To further evaluate the proposed approach we tested our method with real data. One of the relevant contributions of this paper is theoretical. When compared to the state-of-the-art approaches, we propose a completely new parametrization of the problem that can be solved in four simple steps. In addition, our approach does not require any predefined transformation of the dataset, which yields a simpler solution for the problem.

  19. POSE Algorithms for Automated Docking

    NASA Technical Reports Server (NTRS)

    Heaton, Andrew F.; Howard, Richard T.

    2011-01-01

    POSE (relative position and attitude) can be computed in many different ways. Given a sensor that measures bearing to a finite number of spots corresponding to known features (such as a target) of a spacecraft, a number of different algorithms can be used to compute the POSE. NASA has sponsored the development of a flash LIDAR proximity sensor called the Vision Navigation Sensor (VNS) for use by the Orion capsule in future docking missions. This sensor generates data that can be used by a variety of algorithms to compute POSE solutions inside of 15 meters, including at the critical docking range of approximately 1-2 meters. Previously NASA participated in a DARPA program called Orbital Express that achieved the first automated docking for the American space program. During this mission a large set of high quality mated sensor data was obtained at what is essentially the docking distance. This data set is perhaps the most accurate truth data in existence for docking proximity sensors in orbit. In this paper, the flight data from Orbital Express is used to test POSE algorithms at 1.22 meters range. Two different POSE algorithms are tested for two different Fields-of-View (FOVs) and two different pixel noise levels. The results of the analysis are used to predict future performance of the POSE algorithms with VNS data.

  20. Dismount Threat Recognition through Automatic Pose Identification

    DTIC Science & Technology

    2012-03-01

    camera and joint estimation software of the Kinect for Xbox 360. A threat determination is made based on the pose identified by the network. Ac- curacy...The automobile industry continues to refine pedestrian avoidance systems to assist drivers [14,15]. Microsoft’s Kinect for Xbox 360 [3] uses real-time...in Fig. 2.2. Some key problems with this methodology are that cultural differences and weather variances are not taken into account . In some cultures

  1. Person re-identification by pose priors

    NASA Astrophysics Data System (ADS)

    Bak, Slawomir; Martins, Filipe; Bremond, Francois

    2015-03-01

    The person re-identification problem is a well known retrieval task that requires finding a person of interest in a network of cameras. In a real-world scenario, state of the art algorithms are likely to fail due to serious perspective and pose changes as well as variations in lighting conditions across the camera network. The most effective approaches try to cope with all these changes by applying metric learning tools to find a transfer function between a camera pair. Unfortunately, this transfer function is usually dependent on the camera pair and requires labeled training data for each camera. This might be unattainable in a large camera network. In this paper, instead of learning the transfer function that addresses all appearance changes, we propose to learn a generic metric pool that only focuses on pose changes. This pool consists of metrics, each one learned to match a specific pair of poses. Automatically estimated poses determine the proper metric, thus improving matching. We show that metrics learned using a single camera improve the matching across the whole camera network, providing a scalable solution. We validated our approach on a publicly available dataset demonstrating increase in the re-identification performance.

  2. Problem Posing and Problem Solving in a Math Teacher's Circle

    ERIC Educational Resources Information Center

    Appleton, Eric; Farina, Solange; Holzer, Tyler; Kotelawala, Usha; Trushkowsky, Mark

    2017-01-01

    This article describes the New York City Community of Adult Math Instructors (CAMI), a math teachers' circle founded in November 2014. The authors share details about their own participation in CAMI to show the professional growth that research-based, peer-led professional development can offer for adult educators.

  3. MINACE-filter-based facial pose estimation

    NASA Astrophysics Data System (ADS)

    Casasent, David P.; Patnaik, Rohit

    2005-03-01

    A facial pose estimation system is presented that functions with illumination variations present. Pose estimation is a useful first stage in a face recognition system. A separate minimum noise and correlation energy (MINACE) filter is synthesized for each pose. To select the MINACE parameter c for the filter for a pose, a training set of illumination differences of several faces at that pose, and a validation set of other poses (illumination differences of several faces at a few other poses) is used in the automated filter-synthesis step. However, the filter for each pose is a combination of faces at only that pose. The pose estimation system is evaluated using images from the CMU Pose, Illumination and Expression (PIE) database. The classification performance (PC) scores are presented for several pose estimation tests. The pose estimate will be used for a subsequent image transformation of a test face to a reference pose for face identification.

  4. Face pose tracking using the four-point algorithm

    NASA Astrophysics Data System (ADS)

    Fung, Ho Yin; Wong, Kin Hong; Yu, Ying Kin; Tsui, Kwan Pang; Kam, Ho Chuen

    2017-06-01

    In this paper, we have developed an algorithm to track the pose of a human face robustly and efficiently. Face pose estimation is very useful in many applications such as building virtual reality systems and creating an alternative input method for the disabled. Firstly, we have modified a face detection toolbox called DLib for the detection of a face in front of a camera. The detected face features are passed to a pose estimation method, known as the four-point algorithm, for pose computation. The theory applied and the technical problems encountered during system development are discussed in the paper. It is demonstrated that the system is able to track the pose of a face in real time using a consumer grade laptop computer.

  5. 3-D Pose Presentation for Training Applications

    ERIC Educational Resources Information Center

    Fox, Kaitlyn; Whitehead, Anthony

    2011-01-01

    Purpose: In the authors' experience, the biggest issue with pose-based exergames is the difficulty in effectively communicating a three-dimensional pose to a user to facilitate a thorough understanding for accurate pose replication. The purpose of this paper is to examine options for pose presentation. Design/methodology/approach: The authors…

  6. 3-D Pose Presentation for Training Applications

    ERIC Educational Resources Information Center

    Fox, Kaitlyn; Whitehead, Anthony

    2011-01-01

    Purpose: In the authors' experience, the biggest issue with pose-based exergames is the difficulty in effectively communicating a three-dimensional pose to a user to facilitate a thorough understanding for accurate pose replication. The purpose of this paper is to examine options for pose presentation. Design/methodology/approach: The authors…

  7. Human Pose Estimation from Monocular Images: A Comprehensive Survey

    PubMed Central

    Gong, Wenjuan; Zhang, Xuena; Gonzàlez, Jordi; Sobral, Andrews; Bouwmans, Thierry; Tu, Changhe; Zahzah, El-hadi

    2016-01-01

    Human pose estimation refers to the estimation of the location of body parts and how they are connected in an image. Human pose estimation from monocular images has wide applications (e.g., image indexing). Several surveys on human pose estimation can be found in the literature, but they focus on a certain category; for example, model-based approaches or human motion analysis, etc. As far as we know, an overall review of this problem domain has yet to be provided. Furthermore, recent advancements based on deep learning have brought novel algorithms for this problem. In this paper, a comprehensive survey of human pose estimation from monocular images is carried out including milestone works and recent advancements. Based on one standard pipeline for the solution of computer vision problems, this survey splits the problem into several modules: feature extraction and description, human body models, and modeling methods. Problem modeling methods are approached based on two means of categorization in this survey. One way to categorize includes top-down and bottom-up methods, and another way includes generative and discriminative methods. Considering the fact that one direct application of human pose estimation is to provide initialization for automatic video surveillance, there are additional sections for motion-related methods in all modules: motion features, motion models, and motion-based methods. Finally, the paper also collects 26 publicly available data sets for validation and provides error measurement methods that are frequently used. PMID:27898003

  8. Fast human pose estimation using 3D Zernike descriptors

    NASA Astrophysics Data System (ADS)

    Berjón, Daniel; Morán, Francisco

    2012-03-01

    Markerless video-based human pose estimation algorithms face a high-dimensional problem that is frequently broken down into several lower-dimensional ones by estimating the pose of each limb separately. However, in order to do so they need to reliably locate the torso, for which they typically rely on time coherence and tracking algorithms. Their losing track usually results in catastrophic failure of the process, requiring human intervention and thus precluding their usage in real-time applications. We propose a very fast rough pose estimation scheme based on global shape descriptors built on 3D Zernike moments. Using an articulated model that we configure in many poses, a large database of descriptor/pose pairs can be computed off-line. Thus, the only steps that must be done on-line are the extraction of the descriptors for each input volume and a search against the database to get the most likely poses. While the result of such process is not a fine pose estimation, it can be useful to help more sophisticated algorithms to regain track or make more educated guesses when creating new particles in particle-filter-based tracking schemes. We have achieved a performance of about ten fps on a single computer using a database of about one million entries.

  9. Flameless Candle Batteries Pose Risk to Kids

    MedlinePlus

    ... medlineplus.gov/news/fullstory_162882.html Flameless Candle Batteries Pose Risk to Kids If swallowed, serious damage ... WEDNESDAY, Jan. 4, 2017 (HealthDay News) -- Tiny button batteries that light up flameless "tea candles" pose a ...

  10. Relative Camera Pose Estimation Method Using Optimization on the Manifold

    NASA Astrophysics Data System (ADS)

    Cheng, C.; Hao, X.; Li, J.

    2017-05-01

    To solve the problem of relative camera pose estimation, a method using optimization with respect to the manifold is proposed. Firstly from maximum-a-posteriori (MAP) model to nonlinear least squares (NLS) model, the general state estimation model using optimization is derived. Then the camera pose estimation model is applied to the general state estimation model, while the parameterization of rigid body transformation is represented by Lie group/algebra. The jacobian of point-pose model with respect to Lie group/algebra is derived in detail and thus the optimization model of rigid body transformation is established. Experimental results show that compared with the original algorithms, the approaches with optimization can obtain higher accuracy both in rotation and translation, while avoiding the singularity of Euler angle parameterization of rotation. Thus the proposed method can estimate relative camera pose with high accuracy and robustness.

  11. Viewpoint Invariant Gesture Recognition and 3D Hand Pose Estimation Using RGB-D

    ERIC Educational Resources Information Center

    Doliotis, Paul

    2013-01-01

    The broad application domain of the work presented in this thesis is pattern classification with a focus on gesture recognition and 3D hand pose estimation. One of the main contributions of the proposed thesis is a novel method for 3D hand pose estimation using RGB-D. Hand pose estimation is formulated as a database retrieval problem. The proposed…

  12. Image-based aircraft pose estimation: a comparison of simulations and real-world data

    NASA Astrophysics Data System (ADS)

    Breuers, Marcel G. J.; de Reus, Nico

    2001-10-01

    The problem of estimating aircraft pose information from mono-ocular image data is considered using a Fourier descriptor based algorithm. The dependence of pose estimation accuracy on image resolution and aspect angle is investigated through simulations using sets of synthetic aircraft images. Further evaluation shows that god pose estimation accuracy can be obtained in real world image sequences.

  13. Viewpoint Invariant Gesture Recognition and 3D Hand Pose Estimation Using RGB-D

    ERIC Educational Resources Information Center

    Doliotis, Paul

    2013-01-01

    The broad application domain of the work presented in this thesis is pattern classification with a focus on gesture recognition and 3D hand pose estimation. One of the main contributions of the proposed thesis is a novel method for 3D hand pose estimation using RGB-D. Hand pose estimation is formulated as a database retrieval problem. The proposed…

  14. Algorithms for striking material and energy balances in calculating the technical-and-economic indicators of thermal power plant equipment based on the ill-posed problem regularization method

    NASA Astrophysics Data System (ADS)

    Leduhovsky, G. V.; Zhukov, V. P.; Barochkin, E. V.; Zimin, A. P.; Razinkov, A. A.

    2015-08-01

    The problem of striking material and energy balances from the data received by thermal power plant computerized automation systems from the technical accounting systems with the accuracy determined by the metrological characteristics of serviceable calibrated instruments is formulated using the mathematical apparatus of ridge regression method. A graph theory based matrix model of material and energy flows in systems having an intricate structure is proposed, using which it is possible to formalize the solution of a particular practical problem at the stage of constructing the system model. The problem of striking material and energy balances is formulated taking into account different degrees of trustworthiness with which the initial flow rates of coolants and their thermophysical parameters were determined, as well as process constraints expressed in terms of balance correlations on mass and energy for individual system nodes or for any combination thereof. Analytic and numerical solutions of the problem are proposed in different versions of its statement differing from each other in the adopted assumptions and considered constraints. It is shown how the procedure for striking material and energy balances from the results of measuring the flows of feed water and steam in the thermal process circuit of a combined heat and power plant affects the calculation accuracy of specific fuel rates for supplying heat and electricity. It has been revealed that the nominal values of indicators and the fuel saving or overexpenditure values associated with these indicators are the most dependent parameters. In calculating these quantities using different balance striking procedures, an error may arise the value of which is commensurable with the power plant thermal efficiency margin stipulated by the regulatory-technical documents on using fuel. The study results were used for substantiating the choice of stating the problem of striking material and fuel balances, as well as

  15. Performance d'un hôpital de zone sanitaire au Benin: un exemple de modèle d’évaluation

    PubMed Central

    Ahanhanzo, Yolaine Glèlè; Ouédraogo, Landaogo Soutongonoma Lionel; Saizonou, Jacques

    2014-01-01

    Introduction Premier niveau de référence de la pyramide sanitaire du Bénin, les hôpitaux de zone sanitaire s'acquittent de leurs missions dans un contexte difficile. L'objectif de la présente étude a été d’évaluer la performance de l'hôpital de la zone sanitaire de Comè en 2013. Méthodes L’étude était transversale, descriptive et évaluative. Les services retenus ont été sélectionnés par choix raisonné du fait de leur contribution au paquet d'activités de l'hôpital. Les clients externes et internes ont été sélectionnés par commodité. Les membres du conseil de gestion de l'hôpital de zone, les responsables d'organisation à base communautaire, les partenaires techniques et financiers ainsi que des chefs d'arrondissement ont été sélectionné par choix raisonné. La performance de l'hôpital a été mesurée à travers trois critères que sont la qualité des prestations, leur équité d'accès et leur pérennité. L'analyse des données a été faite sur la base de critères en utilisant une cotation analytique puis temporelle. Résultats La performance de l'hôpital de la zone sanitaire de Comè était très faible au premier semestre 2013 avec une qualité des prestations cotée à 35%, une équité d'accès cotée à 50% et une pérennité des actions cotée à 11%. Seul le niveau d'application de la fonction gouvernance était moyen. La méconnaissance des attributions des représentants de la communauté dans les instances de l'hôpital a constitué une limite à leur implication dans l'exercice des fonctions de l'hôpital. Les partenaires techniques et financiers ont participé au renforcement institutionnel de l'hôpital en termes d'amélioration du plateau technique. Conclusion L'application des fonctions de l'hôpital et une meilleure implication de la communauté ainsi que des partenaires contribueront à l'amélioration de la performance de l'hôpital de la zone sanitaire de Comè. PMID:25400830

  16. Pose-Invariant Face Recognition via RGB-D Images

    PubMed Central

    Sang, Gaoli; Li, Jing; Zhao, Qijun

    2016-01-01

    Three-dimensional (3D) face models can intrinsically handle large pose face recognition problem. In this paper, we propose a novel pose-invariant face recognition method via RGB-D images. By employing depth, our method is able to handle self-occlusion and deformation, both of which are challenging problems in two-dimensional (2D) face recognition. Texture images in the gallery can be rendered to the same view as the probe via depth. Meanwhile, depth is also used for similarity measure via frontalization and symmetric filling. Finally, both texture and depth contribute to the final identity estimation. Experiments on Bosphorus, CurtinFaces, Eurecom, and Kiwi databases demonstrate that the additional depth information has improved the performance of face recognition with large pose variations and under even more challenging conditions. PMID:26819581

  17. Perspective projection for variance pose face recognition from camera calibration

    NASA Astrophysics Data System (ADS)

    Fakhir, M. M.; Woo, W. L.; Chambers, J. A.; Dlay, S. S.

    2016-04-01

    Variance pose is an important research topic in face recognition. The alteration of distance parameters across variance pose face features is a challenging. We provide a solution for this problem using perspective projection for variance pose face recognition. Our method infers intrinsic camera parameters of the image which enable the projection of the image plane into 3D. After this, face box tracking and centre of eyes detection can be identified using our novel technique to verify the virtual face feature measurements. The coordinate system of the perspective projection for face tracking allows the holistic dimensions for the face to be fixed in different orientations. The training of frontal images and the rest of the poses on FERET database determine the distance from the centre of eyes to the corner of box face. The recognition system compares the gallery of images against different poses. The system initially utilises information on position of both eyes then focuses principally on closest eye in order to gather data with greater reliability. Differentiation between the distances and position of the right and left eyes is a unique feature of our work with our algorithm outperforming other state of the art algorithms thus enabling stable measurement in variance pose for each individual.

  18. Robust head pose estimation via supervised manifold learning.

    PubMed

    Wang, Chao; Song, Xubo

    2014-05-01

    Head poses can be automatically estimated using manifold learning algorithms, with the assumption that with the pose being the only variable, the face images should lie in a smooth and low-dimensional manifold. However, this estimation approach is challenging due to other appearance variations related to identity, head location in image, background clutter, facial expression, and illumination. To address the problem, we propose to incorporate supervised information (pose angles of training samples) into the process of manifold learning. The process has three stages: neighborhood construction, graph weight computation and projection learning. For the first two stages, we redefine inter-point distance for neighborhood construction as well as graph weight by constraining them with the pose angle information. For Stage 3, we present a supervised neighborhood-based linear feature transformation algorithm to keep the data points with similar pose angles close together but the data points with dissimilar pose angles far apart. The experimental results show that our method has higher estimation accuracy than the other state-of-art algorithms and is robust to identity and illumination variations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Neuromorphic Event-Based 3D Pose Estimation

    PubMed Central

    Reverter Valeiras, David; Orchard, Garrick; Ieng, Sio-Hoi; Benosman, Ryad B.

    2016-01-01

    Pose estimation is a fundamental step in many artificial vision tasks. It consists of estimating the 3D pose of an object with respect to a camera from the object's 2D projection. Current state of the art implementations operate on images. These implementations are computationally expensive, especially for real-time applications. Scenes with fast dynamics exceeding 30–60 Hz can rarely be processed in real-time using conventional hardware. This paper presents a new method for event-based 3D object pose estimation, making full use of the high temporal resolution (1 μs) of asynchronous visual events output from a single neuromorphic camera. Given an initial estimate of the pose, each incoming event is used to update the pose by combining both 3D and 2D criteria. We show that the asynchronous high temporal resolution of the neuromorphic camera allows us to solve the problem in an incremental manner, achieving real-time performance at an update rate of several hundreds kHz on a conventional laptop. We show that the high temporal resolution of neuromorphic cameras is a key feature for performing accurate pose estimation. Experiments are provided showing the performance of the algorithm on real data, including fast moving objects, occlusions, and cases where the neuromorphic camera and the object are both in motion. PMID:26834547

  20. Astronauts Hart and Crippen pose with MMU

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Astronaut Terry J. Hart, 41-C mission specialist, poses with a mockup of the manned maneuvering unit (MMU) in the JSC mockup and integration laboratory (29463); Astronaut Robert L. Crippen, 41-C crew commander, poses with a ground training version of the MMU in the JSC mockup and integration laboratory (29464).

  1. Tracking Human Pose Using Max-Margin Markov Models.

    PubMed

    Zhao, Lin; Gao, Xinbo; Tao, Dacheng; Li, Xuelong

    2015-12-01

    We present a new method for tracking human pose by employing max-margin Markov models. Representing a human body by part-based models, such as pictorial structure, the problem of pose tracking can be modeled by a discrete Markov random field. Considering max-margin Markov networks provide an efficient way to deal with both structured data and strong generalization guarantees, it is thus natural to learn the model parameters using the max-margin technique. Since tracking human pose needs to couple limbs in adjacent frames, the model will introduce loops and will be intractable for learning and inference. Previous work has resorted to pose estimation methods, which discard temporal information by parsing frames individually. Alternatively, approximate inference strategies have been used, which can overfit to statistics of a particular data set. Thus, the performance and generalization of these methods are limited. In this paper, we approximate the full model by introducing an ensemble of two tree-structured sub-models, Markov networks for spatial parsing and Markov chains for temporal parsing. Both models can be trained jointly using the max-margin technique, and an iterative parsing process is proposed to achieve the ensemble inference. We apply our model on three challengeable data sets, which contains highly varied and articulated poses. Comprehensive experimental results demonstrate the superior performance of our method over the state-of-the-art approaches.

  2. Numerical Solution of Ill Posed Problems in Partial Differential Equations

    DTIC Science & Technology

    1988-06-30

    periodic solutions of semilinear wave equations in exterior domains (breathers). Necessary and sufficient conditions for the existence of such solutions...numerically, that radial, global , positive solutions of the equation div grad u + uq u = 0 (X > 0, q > 1). ((1+1grad ul ) / exist for all X sufficiently... equation with a semilinear boundary condition , to appear in SIAM J. Math. Anal. 17] Levine, H.A. and Protter, M.H., The breakdown of solutions of

  3. Numerical Solution of Ill Posed Problems in Partial Differential Equations.

    DTIC Science & Technology

    1987-09-01

    periodic solutions of semilinear wave equations in exterior domains (breathers). Necessary and sufficient conditions for the existence of such...Crandall, M.G., and Sacks, P.E., Some L1 existence and depandence results for semilinear elliptic equations under nonlinear boundary conditions , to...the former case, a convective diffusion equation with a semilinear source in the boundary condition was analyzed. A fairly complete picture of the

  4. Effects of Generative Video on Students' Scientific Problem Posing. Draft.

    ERIC Educational Resources Information Center

    Hickey, Daniel T.; Petrosino, Anthony

    A central premise of the discovery-learning and progressive education movements was that the child's own questions are the most appropriate starting point for instruction. Recent advances present new opportunities for discovery-oriented learning. This project has been attempting to create a classroom environment which affords students the…

  5. Hazardous Waste Sites Pose Investigation, Evaluation, Scientific, and Legal Problems.

    DTIC Science & Technology

    1981-04-24

    EPA has emphasized the development of short- term tests to detect a chemical’s genotoxic potential, that is, its ability to alter a cell’s genetic... wave of incredulity through the Michigan farm community. No appeal was filedi. The ruling also had a significant impact on the approxi- mately 83 other...measurements such as ground penetrating radar, seismic reflection, electromagnetic induction, and magnetometry will be made to help in detailed geophysical

  6. Joining problems posed by the development of materials

    NASA Astrophysics Data System (ADS)

    Colombie, M.

    A review of new materials is conducted to examine joining difficulties caused by the properties of the advanced materials. Attention is given to recent developments in the areas of polymers, ceramics, composite materials, and metal alloys. Fabrication procedures are outlined for traditional metals including continuous methods, and associated levels of purity are described that can be achieved with traditional materials such as steel. Recently developed materials discussed include 'multimaterials' such as Al alloys and polymer composites as well as the metallurgical techniques developed for their fabrication. The production of metal/ceramic combinations by means of diffusion bonding and welding is shown to require development, and fabrication methods are required that insure the production of reproducible and consistent materials.

  7. Leveling Students' Creative Thinking in Solving and Posing Mathematical Problem

    ERIC Educational Resources Information Center

    Siswono, Tatag Yuli Eko

    2010-01-01

    Many researchers assume that people are creative, but their degree of creativity is different. The notion of creative thinking level has been discussed .by experts. The perspective of mathematics creative thinking refers to a combination of logical and divergent thinking which is based on intuition but has a conscious aim. The divergent thinking…

  8. Use of registry employees can pose legal problems.

    PubMed

    Hoffman, S F

    1994-07-01

    In view of the potential legal liability to which a recipient entity can be exposed when using registry employees, some care must be taken in drafting registry contract services and in modulating the recipient entity's behavior towards the registry personnel. The following steps should generally be taken by health care establishments purchasing registry services to minimize such exposure: (1) Ensure that the registry treats its personnel as employees and complies with all applicable employment law obligations, including state and federal employment tax requirements, workers' compensation laws, and any state law wage and hour requirements in the recipient's state. (2) If using an out-of-state registry, make sure that the registry also has workers' compensation insurance in the recipient's state and complies with that state workers' compensation laws. (3) Make sure that termination decisions regarding registry employees are not made for reasons that violate any federal anti-discrimination laws. (4) Provide in the registry agreement for full indemnification by the registry to the recipient. (5) Ensure that the registry is solvent and has adequate insurance to honor its indemnification obligation. (6) Obtain a warranty from the registry that it carefully screens all of its employees before hiring them. (7) Expressly state in the registry agreement that the registry has the right to discipline and supervise the personnel it refers. (8) Do not reject registry personnel for reasons that would be improper with respect to the facility's own employees, e.g., race, sex, age, religion, disability, etc.

  9. Problem Posing in Teacher Education: A Freirian Approach

    ERIC Educational Resources Information Center

    Houser, Neil O.

    2007-01-01

    What kinds of ideas and issues do teachers, students, and citizens in general need to think about at this time in the history of society? And how can we in higher education address these important matters? This article offers one means by which such issues might be approached, in and through teacher education. Drawing on the critical work of Paulo…

  10. Manifolds for pose tracking from monocular video

    NASA Astrophysics Data System (ADS)

    Basu, Saurav; Poulin, Joshua; Acton, Scott T.

    2015-03-01

    We formulate a simple human-pose tracking theory from monocular video based on the fundamental relationship between changes in pose and image motion vectors. We investigate the natural embedding of the low-dimensional body pose space into a high-dimensional space of body configurations that behaves locally in a linear manner. The embedded manifold facilitates the decomposition of the image motion vectors into basis motion vector fields of the tangent space to the manifold. This approach benefits from the style invariance of image motion flow vectors, and experiments to validate the fundamental theory show reasonable accuracy (within 4.9 deg of the ground truth).

  11. Genetic Research on Biospecimens Poses Minimal Risk

    PubMed Central

    Wendler, David S.; Rid, Annette

    2014-01-01

    Genetic research on human biospecimens is increasingly common. Yet, debate continues over the level of risk that this research poses to sample donors. Some argue that genetic research on biospecimens poses minimal risk; others argue that it poses greater than minimal risk and therefore needs additional requirements and limitations. This debate raises concern that some donors are not receiving appropriate protection or, conversely, that valuable research is being subject to unnecessary requirements and limitations. The present paper attempts to address this concern using the widely-endorsed ‘risks of daily life’ standard. The three extant versions of this standard all suggest that, with proper measures in place to protect donor confidentiality, most genetic research on human biospecimens poses minimal risk to donors. PMID:25530152

  12. CHALLENGES POSED BY RETIRED RUSSIAN NUCLEAR SUBMARINES

    SciTech Connect

    Rudolph, Dieter; Kroken, Ingjerd; Latyshev, Eduard; Griffith, Andrew

    2003-02-27

    The purpose of this paper is to provide an overview of the challenges posed by retired Russian nuclear submarines, review current U.S. and International efforts and provide an assessment of the success of these efforts.

  13. Robust pose determination for autonomous docking

    SciTech Connect

    Goddard, J.S.; Jatko, W.B.; Ferrell, R.K.; Gleason, S.S.

    1995-12-31

    This paper describes current work at the Oak Ridge National Laboratory to develop a robotic vision system capable of recognizing designated objects by their intrinsic geometry. This method, based on single camera vision, combines point features and a model-based technique using geometric feature matching for the pose calculation. In this approach, 2-D point features are connected into higher-order shapes and then matched with corresponding features of the model. Pose estimates are made using a closed-form point solution based on model features of four coplanar points. Rotations are represented by quaternions that simplify the calculations in determining the least squares solution for the coordinate transformation. This pose determination method including image acquisition, feature extraction, feature correspondence, and pose calculation has been implemented on a real-time system using a standard camera and image processing hardware. Experimental results are given for relative error measurements.

  14. Learning toward practical head pose estimation

    NASA Astrophysics Data System (ADS)

    Sang, Gaoli; He, Feixiang; Zhu, Rong; Xuan, Shibin

    2017-08-01

    Head pose is useful information for many face-related tasks, such as face recognition, behavior analysis, human-computer interfaces, etc. Existing head pose estimation methods usually assume that the face images have been well aligned or that sufficient and precise training data are available. In practical applications, however, these assumptions are very likely to be invalid. This paper first investigates the impact of the failure of these assumptions, i.e., misalignment of face images, uncertainty and undersampling of training data, on head pose estimation accuracy of state-of-the-art methods. A learning-based approach is then designed to enhance the robustness of head pose estimation to these factors. To cope with misalignment, instead of using hand-crafted features, it seeks suitable features by learning from a set of training data with a deep convolutional neural network (DCNN), such that the training data can be best classified into the correct head pose categories. To handle uncertainty and undersampling, it employs multivariate labeling distributions (MLDs) with dense sampling intervals to represent the head pose attributes of face images. The correlation between the features and the dense MLD representations of face images is approximated by a maximum entropy model, whose parameters are optimized on the given training data. To estimate the head pose of a face image, its MLD representation is first computed according to the model based on the features extracted from the image by the trained DCNN, and its head pose is then assumed to be the one corresponding to the peak in its MLD. Evaluation experiments on the Pointing'04, FacePix, Multi-PIE, and CASIA-PEAL databases prove the effectiveness and efficiency of the proposed method.

  15. Exemplar-based human action pose correction.

    PubMed

    Shen, Wei; Deng, Ke; Bai, Xiang; Leyvand, Tommer; Guo, Baining; Tu, Zhuowen

    2014-07-01

    The launch of Xbox Kinect has built a very successful computer vision product and made a big impact on the gaming industry. This sheds lights onto a wide variety of potential applications related to action recognition. The accurate estimation of human poses from the depth image is universally a critical step. However, existing pose estimation systems exhibit failures when facing severe occlusion. In this paper, we propose an exemplar-based method to learn to correct the initially estimated poses. We learn an inhomogeneous systematic bias by leveraging the exemplar information within a specific human action domain. Furthermore, as an extension, we learn a conditional model by incorporation of pose tags to further increase the accuracy of pose correction. In the experiments, significant improvements on both joint-based skeleton correction and tag prediction are observed over the contemporary approaches, including what is delivered by the current Kinect system. Our experiments for the facial landmark correction also illustrate that our algorithm can improve the accuracy of other detection/estimation systems.

  16. Evaluation and Improvement of Student's Question-Posing Ability in a Web-Based Learning Environment

    ERIC Educational Resources Information Center

    Lan, Yu-Feng; Lin, Pin-Chuan

    2011-01-01

    With the rapid development of web-based learning environments, question-posing activities have become an important teaching and learning mode. However, this learning approach has some difficulties, one being the lack of a practical approach to assist teachers in evaluating the question-posing ability of all learners. To remedy this problem, the…

  17. Perspective Pose Estimation with Geometric Algebra

    NASA Astrophysics Data System (ADS)

    Gebken, Christian; Sommer, Gerald

    2008-09-01

    A novel method which entirely resides inside conformal geometric algebra (CGA) is presented estimating the pose of a camera from one image of a known object. At first, subproblems covering only three feature points are solved and globally assessed. The object model is accordingly pruned and rigidly fitted to corresponding projection rays by evaluating a succinct CGA expression which emerged from a purely geometric approach. It results a set of 3-point poses each given by a motor. These spinor elements of CGA embody rigid body motions from the manifold SE(3). The poses are then to be averaged according to their quality. This is the second aspect of this work as the respective motors do not come from a linear space and averaging must be carried out appropriately. For this purpose, a technique called weighted intrinsic mean is used.

  18. Yoga Poses Increase Subjective Energy and State Self-Esteem in Comparison to 'Power Poses'.

    PubMed

    Golec de Zavala, Agnieszka; Lantos, Dorottya; Bowden, Deborah

    2017-01-01

    Research on beneficial consequences of yoga focuses on the effects of yogic breathing and meditation. Less is known about the psychological effects of performing yoga postures. The present study investigated the effects of yoga poses on subjective sense of energy and self-esteem. The effects of yoga postures were compared to the effects of 'power poses,' which arguably increase the sense of power and self-confidence due to their association with interpersonal dominance (Carney et al., 2010). The study tested the novel prediction that yoga poses, which are not associated with interpersonal dominance but increase bodily energy, would increase the subjective feeling of energy and therefore increase self-esteem compared to 'high power' and 'low power' poses. A two factorial, between participants design was employed. Participants performed either two standing yoga poses with open front of the body (n = 19), two standing yoga poses with covered front of the body (n = 22), two expansive, high power poses (n = 21), or two constrictive, low power poses (n = 20) for 1-min each. The results showed that yoga poses in comparison to 'power poses' increased self-esteem. This effect was mediated by an increased subjective sense of energy and was observed when baseline trait self-esteem was controlled for. These results suggest that the effects of performing open, expansive body postures may be driven by processes other than the poses' association with interpersonal power and dominance. This study demonstrates that positive effects of yoga practice can occur after performing yoga poses for only 2 min.

  19. Maximal likelihood correspondence estimation for face recognition across pose.

    PubMed

    Li, Shaoxin; Liu, Xin; Chai, Xiujuan; Zhang, Haihong; Lao, Shihong; Shan, Shiguang

    2014-10-01

    Due to the misalignment of image features, the performance of many conventional face recognition methods degrades considerably in across pose scenario. To address this problem, many image matching-based methods are proposed to estimate semantic correspondence between faces in different poses. In this paper, we aim to solve two critical problems in previous image matching-based correspondence learning methods: 1) fail to fully exploit face specific structure information in correspondence estimation and 2) fail to learn personalized correspondence for each probe image. To this end, we first build a model, termed as morphable displacement field (MDF), to encode face specific structure information of semantic correspondence from a set of real samples of correspondences calculated from 3D face models. Then, we propose a maximal likelihood correspondence estimation (MLCE) method to learn personalized correspondence based on maximal likelihood frontal face assumption. After obtaining the semantic correspondence encoded in the learned displacement, we can synthesize virtual frontal images of the profile faces for subsequent recognition. Using linear discriminant analysis method with pixel-intensity features, state-of-the-art performance is achieved on three multipose benchmarks, i.e., CMU-PIE, FERET, and MultiPIE databases. Owe to the rational MDF regularization and the usage of novel maximal likelihood objective, the proposed MLCE method can reliably learn correspondence between faces in different poses even in complex wild environment, i.e., labeled face in the wild database.

  20. Point Cloud Based Relative Pose Estimation of a Satellite in Close Range

    PubMed Central

    Liu, Lujiang; Zhao, Gaopeng; Bo, Yuming

    2016-01-01

    Determination of the relative pose of satellites is essential in space rendezvous operations and on-orbit servicing missions. The key problems are the adoption of suitable sensor on board of a chaser and efficient techniques for pose estimation. This paper aims to estimate the pose of a target satellite in close range on the basis of its known model by using point cloud data generated by a flash LIDAR sensor. A novel model based pose estimation method is proposed; it includes a fast and reliable pose initial acquisition method based on global optimal searching by processing the dense point cloud data directly, and a pose tracking method based on Iterative Closest Point algorithm. Also, a simulation system is presented in this paper in order to evaluate the performance of the sensor and generate simulated sensor point cloud data. It also provides truth pose of the test target so that the pose estimation error can be quantified. To investigate the effectiveness of the proposed approach and achievable pose accuracy, numerical simulation experiments are performed; results demonstrate algorithm capability of operating with point cloud directly and large pose variations. Also, a field testing experiment is conducted and results show that the proposed method is effective. PMID:27271633

  1. Point Cloud Based Relative Pose Estimation of a Satellite in Close Range.

    PubMed

    Liu, Lujiang; Zhao, Gaopeng; Bo, Yuming

    2016-06-04

    Determination of the relative pose of satellites is essential in space rendezvous operations and on-orbit servicing missions. The key problems are the adoption of suitable sensor on board of a chaser and efficient techniques for pose estimation. This paper aims to estimate the pose of a target satellite in close range on the basis of its known model by using point cloud data generated by a flash LIDAR sensor. A novel model based pose estimation method is proposed; it includes a fast and reliable pose initial acquisition method based on global optimal searching by processing the dense point cloud data directly, and a pose tracking method based on Iterative Closest Point algorithm. Also, a simulation system is presented in this paper in order to evaluate the performance of the sensor and generate simulated sensor point cloud data. It also provides truth pose of the test target so that the pose estimation error can be quantified. To investigate the effectiveness of the proposed approach and achievable pose accuracy, numerical simulation experiments are performed; results demonstrate algorithm capability of operating with point cloud directly and large pose variations. Also, a field testing experiment is conducted and results show that the proposed method is effective.

  2. Pose tracking for augmented reality applications in outdoor archaeological sites

    NASA Astrophysics Data System (ADS)

    Younes, Georges; Asmar, Daniel; Elhajj, Imad; Al-Harithy, Howayda

    2017-01-01

    In recent years, agencies around the world have invested huge amounts of effort toward digitizing many aspects of the world's cultural heritage. Of particular importance is the digitization of outdoor archaeological sites. In the spirit of valorization of this digital information, many groups have developed virtual or augmented reality (AR) computer applications themed around a particular archaeological object. The problem of pose tracking in outdoor AR applications is addressed. Different positional systems are analyzed, resulting in the selection of a monocular camera-based user tracker. The limitations that challenge this technique from map generation, scale, anchoring, to lighting conditions are analyzed and systematically addressed. Finally, as a case study, our pose tracking system is implemented within an AR experience in the Byblos Roman theater in Lebanon.

  3. 'Button' Batteries Pose Serious Risk to Children

    MedlinePlus

    ... Drugs & Supplements Videos & Tools Español You Are Here: Home → Latest Health News → Article URL of this page: https://medlineplus.gov/news/fullstory_162950.html 'Button' Batteries Pose Serious Risk to Children Toddlers may swallow the tiny batteries used to power many common household objects ...

  4. Common Core Poses Challenges for Preschools

    ERIC Educational Resources Information Center

    Zubrzycki, Jaclyn

    2011-01-01

    Although the common-core standards are calibrated to ensure that students leave K-12 schools ready for work and college, they are also posing challenges for the educators who work with children just starting out their school careers. As 46 states and the District of Columbia work this year to put the new curricular guidelines in place, preschool…

  5. Common Core Poses Challenges for Preschools

    ERIC Educational Resources Information Center

    Zubrzycki, Jaclyn

    2011-01-01

    Although the common-core standards are calibrated to ensure that students leave K-12 schools ready for work and college, they are also posing challenges for the educators who work with children just starting out their school careers. As 46 states and the District of Columbia work this year to put the new curricular guidelines in place, preschool…

  6. "Light" Tobacco Products Pose Heavy Health Risks

    MedlinePlus

    ... For Consumers Home For Consumers Consumer Updates "Light" Tobacco Products Pose Heavy Health Risks Share Tweet Linkedin ... restricting the words “light,” “low,” and “mild” from tobacco products now on the market, as health officials ...

  7. Using glint to perform geometric signature prediction and pose estimation

    NASA Astrophysics Data System (ADS)

    Paulson, Christopher; Zelnio, Edmund; Gorham, LeRoy; Wu, Dapeng

    2012-05-01

    We consider two problems in this paper. The rst problem is to construct a dictionary of elements without using synthetic data or a subset of the data collection; the second problem is to estimate the orientation of the vehicle, independent of the elevation angle. These problems are important to the SAR community because it will alleviate the cost to create the dictionary and reduce the number of elements in the dictionary needed for classication. In order to accomplish these tasks, we utilize the glint phenomenology, which is usually viewed as a hindrance in most algorithms but is valuable information in our research. One way to capitalize on the glint information is to predict the location of the int by using geometry of the single and double bounce phenomenology. After qualitative examination of the results, we were able to deduce that the geometry information was sucient for accurately predicting the location of the glint. Another way that we exploited the glint characteristics was by using it to extract the angle feature which we will use to do the pose estimation. Using this technique we were able to predict the cardinal heading of the vehicle within +/-2° with 96:6% having 0° error. Now this research will have an impact on the classication of SAR images because the geometric prediction will reduce the cost and time to develop and maintain the database for SAR ATR systems and the pose estimation will reduce the computational time and improve accuracy of vehicle classication.

  8. A quaternion pose determination solution based on monocular vision model

    NASA Astrophysics Data System (ADS)

    Chen, Jun; Zhang, Qiuzhi; Zhang, Baoshang

    2011-08-01

    Determination of relative three-dimensional position and orientation between two reference frames can be solved by the pose measuring methods based on monocular vision model. Owing to the special T-shaped configuration, the definition of object rotational matrix in the terms of quaternion elements helped in representing the problem by six nonlinear equations from which a closed-form solution can be obtained for all the unknown parameters. The calculating formulas of elements in the rotational matrix were deduced from the coordinates of feature points in camera frame as well as the converting vector which was also introduced into the process acting as corrected term. An approximate pose could be found by the assumption of zero difference in depth of all points in camera frame, then the converting vector should be initialized by the third row of current rotational matrix. The principle of computing priority of the max value in quaternion expression was proposed to ensure the convergence of the iteration loop through which the final pose was achieved in a few iterations. Simulation experiments show the validity of the solution and analysis of the calculating precision was made in detail. The measuring orientation error would constringe with the reduction of distance from camera focus to target object and performance of the algorithm went well in short distance, while the deformation went larger with the increasing of errors caused by imprecise correspondence.

  9. Driver head pose tracking with thermal camera

    NASA Astrophysics Data System (ADS)

    Bole, S.; Fournier, C.; Lavergne, C.; Druart, G.; Lépine, T.

    2016-09-01

    Head pose can be seen as a coarse estimation of gaze direction. In automotive industry, knowledge about gaze direction could optimize Human-Machine Interface (HMI) and Advanced Driver Assistance Systems (ADAS). Pose estimation systems are often based on camera when applications have to be contactless. In this paper, we explore uncooled thermal imagery (8-14μm) for its intrinsic night vision capabilities and for its invariance versus lighting variations. Two methods are implemented and compared, both are aided by a 3D model of the head. The 3D model, mapped with thermal texture, allows to synthesize a base of 2D projected models, differently oriented and labeled in yaw and pitch. The first method is based on keypoints. Keypoints of models are matched with those of the query image. These sets of matchings, aided with the 3D shape of the model, allow to estimate 3D pose. The second method is a global appearance approach. Among all 2D models of the base, algorithm searches the one which is the closest to the query image thanks to a weighted least squares difference.

  10. A pose prediction approach based on ligand 3D shape similarity

    NASA Astrophysics Data System (ADS)

    Kumar, Ashutosh; Zhang, Kam Y. J.

    2016-06-01

    Molecular docking predicts the best pose of a ligand in the target protein binding site by sampling and scoring numerous conformations and orientations of the ligand. Failures in pose prediction are often due to either insufficient sampling or scoring function errors. To improve the accuracy of pose prediction by tackling the sampling problem, we have developed a method of pose prediction using shape similarity. It first places a ligand conformation of the highest 3D shape similarity with known crystal structure ligands into protein binding site and then refines the pose by repacking the side-chains and performing energy minimization with a Monte Carlo algorithm. We have assessed our method utilizing CSARdock 2012 and 2014 benchmark exercise datasets consisting of co-crystal structures from eight proteins. Our results revealed that ligand 3D shape similarity could substitute conformational and orientational sampling if at least one suitable co-crystal structure is available. Our method identified poses within 2 Å RMSD as the top-ranking pose for 85.7 % of the test cases. The median RMSD for our pose prediction method was found to be 0.81 Å and was better than methods performing extensive conformational and orientational sampling within target protein binding sites. Furthermore, our method was better than similar methods utilizing ligand 3D shape similarity for pose prediction.

  11. Pose detection of a 3D object using template matched filtering

    NASA Astrophysics Data System (ADS)

    Picos, Kenia; Díaz-Ramírez, Víctor H.

    2016-09-01

    The problem of 3D pose recognition of a rigid object is difficult to solve because the pose in a 3D space can vary with multiple degrees of freedom. In this work, we propose an accurate method for 3D pose estimation based on template matched filtering. The proposed method utilizes a bank of space-variant filters which take into account different pose states of the target and local statistical properties of the input scene. The state parameters of location coordinates, orientation angles, and scaling parameters of the target are estimated with high accuracy in the input scene. Experimental tests are performed for real and synthetic scenes. The proposed system yields good performance for 3D pose recognition in terms of detection efficiency, location and orientation errors.

  12. Tabu search for human pose recognition

    NASA Astrophysics Data System (ADS)

    Dyce, W.; Rodriguez, N.; Lange, B.; Andary, S.; Seilles, A.

    2014-03-01

    The use of computer vision techniques to build hands-free input devices has long been a topic of interest to researchers in the field of natural interaction. In recent years Microsoft's Kinect has brought these technologies to the layman, but the most commonly used libraries for Kinect human pose recognition are closed-source. There is not yet an accepted, effective open-source alternative upon which highly specific applications can be based. We propose a novel technique for extracting the appendage configurations of users from the Kinect camera's depth feed, based on stochastic local search techniques rather than per-pixel classification.

  13. Robotic-surgical instrument wrist pose estimation.

    PubMed

    Fabel, Stephan; Baek, Kyungim; Berkelman, Peter

    2010-01-01

    The Compact Lightweight Surgery Robot from the University of Hawaii includes two teleoperated instruments and one endoscope manipulator which act in accord to perform assisted interventional medicine. The relative positions and orientations of the robotic instruments and endoscope must be known to the teleoperation system so that the directions of the instrument motions can be controlled to correspond closely to the directions of the motions of the master manipulators, as seen by the the endoscope and displayed to the surgeon. If the manipulator bases are mounted in known locations and all manipulator joint variables are known, then the necessary coordinate transformations between the master and slave manipulators can be easily computed. The versatility and ease of use of the system can be increased, however, by allowing the endoscope or instrument manipulator bases to be moved to arbitrary positions and orientations without reinitializing each manipulator or remeasuring their relative positions. The aim of this work is to find the pose of the instrument end effectors using the video image from the endoscope camera. The P3P pose estimation algorithm is used with a Levenberg-Marquardt optimization to ensure convergence. The correct transformations between the master and slave coordinate frames can then be calculated and updated when the bases of the endoscope or instrument manipulators are moved to new, unknown, positions at any time before or during surgical procedures.

  14. Mrs. Chandrasekhar poses with contest winners

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Mrs. Lalitha Chandrasekhar (left), wife of the late Indian- American Nobel Laureate Subrahmanyan Chandrasekhar, poses with a model of the Chandra X-ray Observatory and the winners of the contest to rename the telescope in the TRW Media Hospitality Tent at the NASA Press Site at KSC. The winners of the contest are Jatila van der Veen (center), academic coordinator and lecturer, Physics Dept., University of Santa Barbara, Calif., and Tyrel Johnson (right), high school student, Laclede, Idaho. The name 'Chandra,' a shortened version of Chandrasekhar's name which he preferred among friends and colleagues, was chosen to honor the Nobel Laureate. 'Chandra' also means 'Moon' or 'luminous' in Sanskrit. The observatory is scheduled to be launched aboard Columbia on Space Shuttle mission STS-93.

  15. Mrs. Chandrasekhar poses with contest winners

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Mrs. Lalitha Chandrasekhar (left), wife of the late Indian- American Nobel Laureate Subrahmanyan Chandrasekhar, poses with a model of the Chandra X-ray Observatory and the winners of the contest to rename the telescope in the TRW Media Hospitality Tent at the NASA Press Site at KSC. The winners of the contest are Jatila van der Veen (center), academic coordinator and lecturer, Physics Dept., University of Santa Barbara, Calif., and Tyrel Johnson (right), high school student, Laclede, Idaho. The name 'Chandra,' a shortened version of Chandrasekhar's name which he preferred among friends and colleagues, was chosen to honor the Nobel Laureate. 'Chandra' also means 'Moon' or 'luminous' in Sanskrit. The observatory is scheduled to be launched aboard Columbia on Space Shuttle mission STS-93.

  16. Ethical quandaries posing as conflicts of interest.

    PubMed

    Kottow, Miguel

    2010-06-01

    Conflicts of interest are receiving increased attention in medical research, clinical practice and education. Criticism of, and penalties for, conflicts of interest have been insufficiently discussed and have been applied without adequate conceptual backing. Genuine conflicts of interest are situations in which alternative courses of action are ethically equivalent, decision-making being less a matter of moral deliberation than of personal weighing of interest. In contrast, situations usually thought of as conflicts of interest are mostly temptations to follow an attractive but undue option that causes harm by failing to uphold well-entrenched ethical standards. Examples of moral quandaries that pose as ethically neutral conflicts of interest are healthcare providers enticed to favour certain products; patients being referred to non-therapeutic trials entailing risks and non-optimal healthcare; industry-supported scientists failing to deliver unbiased research results and reports or participating in ghost-writing; and sponsored educators who praise their supporters beyond objective evidence. All these are moral blemishes, where integrity gives way to material incentives at the cost of provoking risky and harm-producing situations, thus constituting false conflicts of interest when they are in fact ethical misdemeanours. Disclosure has been the most widely recommended response to avoid the concealment of conflicting and ethically suspect interests. Regulations regarding disclosure reveal a utilitarian stance that shows more concern for the magnitude of support or sponsorship than for the underlying ethical transgression. Education and oversight should directly address and help correct the moral attitude towards undue influence of inducements and marketing strategies falsely posing as conflicts of interest.

  17. Articulated Non-Rigid Point Set Registration for Human Pose Estimation from 3D Sensors

    PubMed Central

    Ge, Song; Fan, Guoliang

    2015-01-01

    We propose a generative framework for 3D human pose estimation that is able to operate on both individual point sets and sequential depth data. We formulate human pose estimation as a point set registration problem, where we propose three new approaches to address several major technical challenges in this research. First, we integrate two registration techniques that have a complementary nature to cope with non-rigid and articulated deformations of the human body under a variety of poses. This unique combination allows us to handle point sets of complex body motion and large pose variation without any initial conditions, as required by most existing approaches. Second, we introduce an efficient pose tracking strategy to deal with sequential depth data, where the major challenge is the incomplete data due to self-occlusions and view changes. We introduce a visible point extraction method to initialize a new template for the current frame from the previous frame, which effectively reduces the ambiguity and uncertainty during registration. Third, to support robust and stable pose tracking, we develop a segment volume validation technique to detect tracking failures and to re-initialize pose registration if needed. The experimental results on both benchmark 3D laser scan and depth datasets demonstrate the effectiveness of the proposed framework when compared with state-of-the-art algorithms. PMID:26131673

  18. Robust and Accurate Vision-Based Pose Estimation Algorithm Based on Four Coplanar Feature Points

    PubMed Central

    Zhang, Zimiao; Zhang, Shihai; Li, Qiu

    2016-01-01

    Vision-based pose estimation is an important application of machine vision. Currently, analytical and iterative methods are used to solve the object pose. The analytical solutions generally take less computation time. However, the analytical solutions are extremely susceptible to noise. The iterative solutions minimize the distance error between feature points based on 2D image pixel coordinates. However, the non-linear optimization needs a good initial estimate of the true solution, otherwise they are more time consuming than analytical solutions. Moreover, the image processing error grows rapidly with measurement range increase. This leads to pose estimation errors. All the reasons mentioned above will cause accuracy to decrease. To solve this problem, a novel pose estimation method based on four coplanar points is proposed. Firstly, the coordinates of feature points are determined according to the linear constraints formed by the four points. The initial coordinates of feature points acquired through the linear method are then optimized through an iterative method. Finally, the coordinate system of object motion is established and a method is introduced to solve the object pose. The growing image processing error causes pose estimation errors the measurement range increases. Through the coordinate system, the pose estimation errors could be decreased. The proposed method is compared with two other existing methods through experiments. Experimental results demonstrate that the proposed method works efficiently and stably. PMID:27999338

  19. Earthquakes Pose a Serious Hazard in Afghanistan

    USGS Publications Warehouse

    Crone, Anthony J.

    2007-01-01

    This report is USGS Afghanistan Project No. 155. This study was funded by an Interagency Agreement between the U.S. Agency for International Development (USAID) and the U.S. Geological Survey. Afghanistan is located in the geologically active part of the world where the northward-moving Indian plate is colliding with the southern part of the Eurasian plate at a rate of about 1.7 inches per year. This collision has created the world's highest mountains and causes slips on major faults that generate large, often devastating earthquakes. Every few years a powerful earthquake causes significant damage or fatalities. New construction needs to be designed to accommodate the hazards posed by strong earthquakes. The U.S. Geological Survey has developed a preliminary seismic-hazard map of Afghanistan. Although the map is generalized, it provides government officials, engineers, and private companies who are interested in participating in Afghanistan's growth with crucial information about the location and nature of seismic hazards.

  20. Researcher Poses with a Nuclear Rocket Model

    NASA Image and Video Library

    1961-11-21

    A researcher at the NASA Lewis Research Center with slide ruler poses with models of the earth and a nuclear-propelled rocket. The Nuclear Engine for Rocket Vehicle Applications (NERVA) was a joint NASA and Atomic Energy Commission (AEC) endeavor to develop a nuclear-powered rocket for both long-range missions to Mars and as a possible upper-stage for the Apollo Program. The early portion of the program consisted of basic reactor and fuel system research. This was followed by a series of Kiwi reactors built to test nuclear rocket principles in a non-flying nuclear engine. The next phase, NERVA, would create an entire flyable engine. The AEC was responsible for designing the nuclear reactor and overall engine. NASA Lewis was responsible for developing the liquid-hydrogen fuel system. The nuclear rocket model in this photograph includes a reactor at the far right with a hydrogen propellant tank and large radiator below. The payload or crew would be at the far left, distanced from the reactor.

  1. Pose Estimation for Augmented Reality: A Hands-On Survey.

    PubMed

    Marchand, Eric; Uchiyama, Hideaki; Spindler, Fabien

    2016-12-01

    Augmented reality (AR) allows to seamlessly insert virtual objects in an image sequence. In order to accomplish this goal, it is important that synthetic elements are rendered and aligned in the scene in an accurate and visually acceptable way. The solution of this problem can be related to a pose estimation or, equivalently, a camera localization process. This paper aims at presenting a brief but almost self-contented introduction to the most important approaches dedicated to vision-based camera localization along with a survey of several extension proposed in the recent years. For most of the presented approaches, we also provide links to code of short examples. This should allow readers to easily bridge the gap between theoretical aspects and practical implementations.

  2. Gaze Estimation From Eye Appearance: A Head Pose-Free Method via Eye Image Synthesis.

    PubMed

    Lu, Feng; Sugano, Yusuke; Okabe, Takahiro; Sato, Yoichi

    2015-11-01

    In this paper, we address the problem of free head motion in appearance-based gaze estimation. This problem remains challenging because head motion changes eye appearance significantly, and thus, training images captured for an original head pose cannot handle test images captured for other head poses. To overcome this difficulty, we propose a novel gaze estimation method that handles free head motion via eye image synthesis based on a single camera. Compared with conventional fixed head pose methods with original training images, our method only captures four additional eye images under four reference head poses, and then, precisely synthesizes new training images for other unseen head poses in estimation. To this end, we propose a single-directional (SD) flow model to efficiently handle eye image variations due to head motion. We show how to estimate SD flows for reference head poses first, and then use them to produce new SD flows for training image synthesis. Finally, with synthetic training images, joint optimization is applied that simultaneously solves an eye image alignment and a gaze estimation. Evaluation of the method was conducted through experiments to assess its performance and demonstrate its effectiveness.

  3. Using head poses to control a virtual robot walking in a virtualmaze

    NASA Astrophysics Data System (ADS)

    Zhao, Qingjie; Xu, Weicun; Wang, Yuxia; Shi, Xiaoming

    2013-05-01

    This paper develops a game system based on head pose identification techniques to control a virtual robot walking in a virtual maze environment built with Microsoft Robotics Developer Studio. Adaboost face classifiers are used to detect a face in the image and give a rough head pose classification. Two approaches are proposed to further determine more specific head poses. The first approach adopts PCA with nose template matching method, and the second one firstly uses a nose classifier to detect the nose in a detected face region and then directly utilizes the nose's relative position information to achieve head pose classification. A method to select the best nose area is proposed to solve the problem that multi-nose areas may be detected in one face region. Experiment results show that the two approaches have comparable time consumed, but the second approach provides more correct identification results.

  4. Transfer between Pose and Illumination Training in Face Recognition

    ERIC Educational Resources Information Center

    Liu, Chang Hong; Bhuiyan, Md. Al-Amin; Ward, James; Sui, Jie

    2009-01-01

    The relationship between pose and illumination learning in face recognition was examined in a yes-no recognition paradigm. The authors assessed whether pose training can transfer to a new illumination or vice versa. Results show that an extensive level of pose training through a face-name association task was able to generalize to a new…

  5. Project Fox: Assessing Risks Posed By Asteroids

    NASA Astrophysics Data System (ADS)

    Reinhardt, J.; Chen, X.; Liu, W.; Manchev, P.; Paté-Cornell, M.

    2013-12-01

    In order to make decisions on how to invest limited research dollars on asteroid surveillance and mitigation options, an analytic understanding of the risks posed by impacts is necessary. Qualitative and quantitative studies have been performed to assess such risks, and some reasonable point estimates have been proposed. However, since consequential asteroid impacts tend to be rare events, point estimates and expected annual death rates do not adequately convey the heavy tail of the distribution, potentially leading to misguided resource allocations. We propose and develop a framework for new risk measures, including a distribution over the number of fatalities from asteroid impacts and the probability of a globally consequential impact. We implement a simulation of asteroid impacts using probabilistic inputs for impactor characteristics, and a Poisson process for asteroid arrivals over the next 100 years. Simulation results indicate that a significant portion of the risk to humans comes from asteroids in the 300-1000 meter diameter range; this is because asteroid impacts in this range can produce global effects, and are more frequent than those from asteroids greater than 1km in diameter. The relative importance of this size regime in overall asteroid impact risk is robust in simulation results, and we find the magnitude of risks is still sensitive to factors that contribute global effects from an asteroid impact. Initial results are provided on the sensitivity of impact risks to various mitigation measures, including 'civil defense' methods. These results underscore the need for next-generation survey missions, and can help provide the basis for setting future space telescope observation requirements.

  6. Incorporating structure from motion uncertainty into image-based pose estimation

    NASA Astrophysics Data System (ADS)

    Ludington, Ben T.; Brown, Andrew P.; Sheffler, Michael J.; Taylor, Clark N.; Berardi, Stephen

    2015-05-01

    A method for generating and utilizing structure from motion (SfM) uncertainty estimates within image-based pose estimation is presented. The method is applied to a class of problems in which SfM algorithms are utilized to form a geo-registered reference model of a particular ground area using imagery gathered during flight by a small unmanned aircraft. The model is then used to form camera pose estimates in near real-time from imagery gathered later. The resulting pose estimates can be utilized by any of the other onboard systems (e.g. as a replacement for GPS data) or downstream exploitation systems, e.g., image-based object trackers. However, many of the consumers of pose estimates require an assessment of the pose accuracy. The method for generating the accuracy assessment is presented. First, the uncertainty in the reference model is estimated. Bundle Adjustment (BA) is utilized for model generation. While the high-level approach for generating a covariance matrix of the BA parameters is straightforward, typical computing hardware is not able to support the required operations due to the scale of the optimization problem within BA. Therefore, a series of sparse matrix operations is utilized to form an exact covariance matrix for only the parameters that are needed at a particular moment. Once the uncertainty in the model has been determined, it is used to augment Perspective-n-Point pose estimation algorithms to improve the pose accuracy and to estimate the resulting pose uncertainty. The implementation of the described method is presented along with results including results gathered from flight test data.

  7. Troubles de la ménopause: enquête sur les connaissances, attitudes et pratiques du personnel des structures sanitaires de Dakar

    PubMed Central

    Diouf, Abdoul Aziz; Faye-Diémé, Marie Edouard; Guèye, Mamour; Sandjon, Tatiana Gisèle; Mbaye, Magatte; Moreau, Jean Charles; Diouf, Alassane

    2014-01-01

    Introduction Evaluer le niveau de connaissance du personnel de santé des structures sanitaires de la région de Dakar, l'attitude et les pratiques face aux troubles de la ménopause. Méthodes Enquête prospective auprès de 135 prestataires avec un questionnaire anonyme divisé en quatre rubriques: les caractéristiques socioprofessionnelles, les connaissances générales sur la ménopause, l'attitude et la pratique du prestataire par rapport à la ménopause troublée. Résultats Les prestataires de santé inclus dans l’étude étaient répartis comme suit: 11 gynécologues, 37 médecins en spécialisation gynécologique, 34 médecins généralistes et 53 sages-femmes d’état. L’âge moyen était de 35 ans. Le sexe féminin représentait 64% du groupe. Vingt et un pourcent des prestataires exerçaient depuis plus de 10 ans. De manière globale, les connaissances générales sur la ménopause étaient satisfaisantes du moment où la majeure partie des prestataires était en mesure de poser le diagnostic et de prévoir les conséquences du déficit hormonal. La majorité des prestataires (62%) était favorable au traitement de la ménopause troublée. Cependant, nous notons une certaine insuffisance dans le traitement de la ménopause, aussi bien dans le cadre de la thérapie hormonale que dans l'utilisation des moyens alternatifs. Conclusion Le nombre de femmes ménopausées augmente progressivement, et il convient de réunir toutes les stratégies de mise à niveau afin de faire face au défit de l'amélioration de la qualité de vie de cette catégorie de la population. PMID:25489362

  8. Evaluation des Connaissances-Attitudes-Pratiques des populations des districts sanitaires de Benoye, Laoukassy, Moundou et N’Djaména Sud sur la rage canine au Tchad

    PubMed Central

    Mindekem, Rolande; Lechenne, Monique; Alfaroukh, Idriss Oumar; Moto, Daugla Doumagoum; Zinsstag, Jakob; Ouedraogo, Laurent Tinoaga; Salifou, Sahidou

    2017-01-01

    Introduction La rage canine demeure une préoccupation en Afrique comme au Tchad. La présente étude vise à évaluer les Connaissances-Attitudes-Pratiques des populations pour la prise en charge appropriée des personnes exposées et une lutte efficace. Méthodes C’était une étude transversale descriptive réalisée en juillet et septembre dans quatre districts sanitaires au Tchad en 2015. Les données ont été collectées à l’aide d’un questionnaire auprès des ménages recrutés suivant un sondage aléatoire à 3 degrés. Résultats C’était 2428 personnes enquêtées avec un niveau maximum primaire (54,12%). L’âge moyen était de 36 ± 13,50 ans. Ils étaient cultivateurs (35,17%), commerçants (18,04%), ménagères (12,81%). La rage était définie comme une maladie transmise du chien à l’homme (41,43%), une altération du cerveau (41,27%), une sous-alimentation (10,26%). Le chat était faiblement connu réservoir (13,84%) et vecteur (19,77%) ainsi que la griffure comme moyen de transmission (4,61%) et la vaccination du chat comme mesure préventive (0,49%). Les premiers soins en cas de morsure à domicile étaient les pratiques traditionnelles (47,69%), le lavage des plaies (19,48%) ou aucune action entreprise (20,43%). Les ménages consultaient la santé humaine (78,50%), la santé animale (5,35%) et les guérisseurs traditionnels (27%). Conclusion La communication en rapport avec des premiers soins à la maison en cas de morsure, la connaissance du chat comme réservoir et vecteur, celle de la griffure comme moyen de transmission et la promotion de la consultation des services vétérinaires en cas de morsure sont nécessaires. PMID:28761600

  9. When a Problem Is More than a Teacher's Question

    ERIC Educational Resources Information Center

    Olson, Jo Clay; Knott, Libby

    2013-01-01

    Not only are the problems teachers pose throughout their teaching of great importance but also the ways in which they use those problems make this a critical component of teaching. A problem-posing episode includes the problem setup, the statement of the problem, and the follow-up questions. Analysis of problem-posing episodes of precalculus…

  10. When a Problem Is More than a Teacher's Question

    ERIC Educational Resources Information Center

    Olson, Jo Clay; Knott, Libby

    2013-01-01

    Not only are the problems teachers pose throughout their teaching of great importance but also the ways in which they use those problems make this a critical component of teaching. A problem-posing episode includes the problem setup, the statement of the problem, and the follow-up questions. Analysis of problem-posing episodes of precalculus…

  11. Do Weekend Deliveries Pose Risks for Moms?

    MedlinePlus

    ... medicine, not just childbirth, said Dr. James Ducey, director of maternal-fetal medicine at Staten Island University Hospital in New York City. Ducey believes the problem is one of weekend staffing. "There are fewer nurses and fewer doctors on duty on the weekend," he said. Women, however, shouldn' ...

  12. Comprendre l'influence des facteurs contextuels sur la participation communautaire à la santé : une étude de cas dans le district sanitaire de Tenkodogo, au Burkina Faso.

    PubMed

    Sombié, Issa; Ilboudo, David O S; Soubeiga, André Kamba; Samuelsen, Helle

    2015-08-07

    Le Burkina Faso met en œuvre depuis plusieurs années la stratégie de la participation communautaire. Des comités de gestion (CoGes) ont été mis en place dans les centres de santé de la première ligne et doivent participer aux prises de décisions. L'objectif principal de cette stratégie est de favoriser l'utilisation des services de santé et une adhésion massive des communautés aux activités de promotion de la santé. Seulement, on constate que les résultats escomptés par les autorités sanitaires tardent à se réaliser. Le présent article convoque les facteurs liés au contexte socioculturel du district sanitaire, pour analyser le phénomène de la participation communautaire.L'étude s'est déroulée dans le district sanitaire de Tenkodogo, situé dans la région administrative du Centre-est, à environ 190 km de la capitale. Cette étude exclusivement qualitative, a utilisé deux méthodes de collecte : les entretiens individuels et les focus groups. Les participants à l'étude sont les chefs de ménage (n = 48), les membres des CoGes (n = 10), les agents de santé (n = 8) et les agents de santé communautaire (n = 24). La méthode de l'analyse de contenu a été utilisée pour l'analyse des données.Les résultats de l'étude montrent que plusieurs facteurs socioculturels influencent la dynamique de la participation communautaire dans le district. Ce sont les conditions économiques, la perception négative des services de santé, les inégalités sociales de sexe et d'âge, le faible ancrage social des organisations communautaires, les rivalités inter-villages et les conflits coutumiers. L'étude relève également que les communautés ne perçoivent pas leur implication dans le processus décisionnel des services de santé comme une priorité. Leurs principales attentes s'orientent vers la disponibilité de soins de qualité et à coût réduit.

  13. Skeleton body pose tracking from efficient three-dimensional motion estimation and volumetric reconstruction.

    PubMed

    Zhang, Zheng; Soon, Hock

    2012-08-10

    We address the problem of body pose tracking in a scenario of multiple camera setup with the aim of recovering body motion robustly and accurately. The tracking is performed on three-dimensional (3D) space using 3D data, including colored volume and 3D optical flow, which are reconstructed at each time step. We introduce strategies to compute multiple camera-based 3D optical flow and have attained efficient and robust 3D motion estimation. Body pose estimation starts with a prediction using 3D optical flow and then is changed to a lower-dimensional global optimization problem. Our method utilizes a voxel subject-specific body model, exploits multiple 3D image cues, and incorporates physical constraints into a stochastic particle-based search initialized from the deterministic prediction and stochastic sampling. It leads to a robust 3D pose tracker. Experiments on publicly available sequences show the robustness and accuracy of our approach.

  14. Pose Invariant Face Recognition Based on Hybrid Dominant Frequency Features

    NASA Astrophysics Data System (ADS)

    Wijaya, I. Gede Pasek Suta; Uchimura, Keiichi; Hu, Zhencheng

    Face recognition is one of the most active research areas in pattern recognition, not only because the face is a human biometric characteristics of human being but also because there are many potential applications of the face recognition which range from human-computer interactions to authentication, security, and surveillance. This paper presents an approach to pose invariant human face image recognition. The proposed scheme is based on the analysis of discrete cosine transforms (DCT) and discrete wavelet transforms (DWT) of face images. From both the DCT and DWT domain coefficients, which describe the facial information, we build compact and meaningful features vector, using simple statistical measures and quantization. This feature vector is called as the hybrid dominant frequency features. Then, we apply a combination of the L2 and Lq metric to classify the hybrid dominant frequency features to a person's class. The aim of the proposed system is to overcome the high memory space requirement, the high computational load, and the retraining problems of previous methods. The proposed system is tested using several face databases and the experimental results are compared to a well-known Eigenface method. The proposed method shows good performance, robustness, stability, and accuracy without requiring geometrical normalization. Furthermore, the purposed method has low computational cost, requires little memory space, and can overcome retraining problem.

  15. Spatio-Temporal Matching for Human Pose Estimation in Video.

    PubMed

    Zhou, Feng; Torre, Fernando De la

    2016-08-01

    Detection and tracking humans in videos have been long-standing problems in computer vision. Most successful approaches (e.g., deformable parts models) heavily rely on discriminative models to build appearance detectors for body joints and generative models to constrain possible body configurations (e.g., trees). While these 2D models have been successfully applied to images (and with less success to videos), a major challenge is to generalize these models to cope with camera views. In order to achieve view-invariance, these 2D models typically require a large amount of training data across views that is difficult to gather and time-consuming to label. Unlike existing 2D models, this paper formulates the problem of human detection in videos as spatio-temporal matching (STM) between a 3D motion capture model and trajectories in videos. Our algorithm estimates the camera view and selects a subset of tracked trajectories that matches the motion of the 3D model. The STM is efficiently solved with linear programming, and it is robust to tracking mismatches, occlusions and outliers. To the best of our knowledge this is the first paper that solves the correspondence between video and 3D motion capture data for human pose detection. Experiments on the CMU motion capture, Human3.6M, Berkeley MHAD and CMU MAD databases illustrate the benefits of our method over state-of-the-art approaches.

  16. Pose Estimation with a Kinect for Ergonomic Studies: Evaluation of the Accuracy Using a Virtual Mannequin

    PubMed Central

    Plantard, Pierre; Auvinet, Edouard; Le Pierres, Anne-Sophie; Multon, Franck

    2015-01-01

    Analyzing human poses with a Kinect is a promising method to evaluate potentials risks of musculoskeletal disorders at workstations. In ecological situations, complex 3D poses and constraints imposed by the environment make it difficult to obtain reliable kinematic information. Thus, being able to predict the potential accuracy of the measurement for such complex 3D poses and sensor placements is challenging in classical experimental setups. To tackle this problem, we propose a new evaluation method based on a virtual mannequin. In this study, we apply this method to the evaluation of joint positions (shoulder, elbow, and wrist), joint angles (shoulder and elbow), and the corresponding RULA (a popular ergonomics assessment grid) upper-limb score for a large set of poses and sensor placements. Thanks to this evaluation method, more than 500,000 configurations have been automatically tested, which would be almost impossible to evaluate with classical protocols. The results show that the kinematic information obtained by the Kinect software is generally accurate enough to fill in ergonomic assessment grids. However inaccuracy strongly increases for some specific poses and sensor positions. Using this evaluation method enabled us to report configurations that could lead to these high inaccuracies. As a supplementary material, we provide a software tool to help designers to evaluate the expected accuracy of this sensor for a set of upper-limb configurations. Results obtained with the virtual mannequin are in accordance with those obtained from a real subject for a limited set of poses and sensor placements. PMID:25599426

  17. Face Recognition with Pose Variations and Misalignment via Orthogonal Procrustes Regression.

    PubMed

    Tai, Ying; Yang, Jian; Zhang, Yigong; Luo, Lei; Qian, Jianjun; Chen, Yu

    2016-04-06

    Linear regression based method is a hot topic in face recognition community. Recently, sparse representation and collaborative representation based classifiers for face recognition have been proposed and attracted great attention. However, most of the existing regression analysis based methods are sensitive to pose variations. In this paper, we introduce the orthogonal Procrustes problem (OPP) as a model to handle pose variations existed in two-dimensional face images. OPP seeks an optimal linear transformation between two images with different poses so as to make the transformed image best fits the other one. We integrate OPP into the regression model and propose the orthogonal Procrustes regression (OPR) model. To address the problem that the linear transformation is not suitable for handling highly non-linear pose variation, we further adopt a progressive strategy and propose the stacked orthogonal Procrustes regression (stacked OPR). As a practical framework, OPR can handle face alignment, pose correction and face representation simultaneously. We optimize the proposed model via an efficient alternating iterative algorithm and experimental results on three popular face databases, CMU PIE database, CMU Multi-PIE database and LFW database, demonstrate the effectiveness of our proposed method.

  18. Face Recognition With Pose Variations and Misalignment via Orthogonal Procrustes Regression.

    PubMed

    Tai, Ying; Yang, Jian; Zhang, Yigong; Luo, Lei; Qian, Jianjun; Chen, Yu

    2016-06-01

    A linear regression-based method is a hot topic in face recognition community. Recently, sparse representation and collaborative representation-based classifiers for face recognition have been proposed and attracted great attention. However, most of the existing regression analysis-based methods are sensitive to pose variations. In this paper, we introduce the orthogonal Procrustes problem (OPP) as a model to handle pose variations existed in 2D face images. OPP seeks an optimal linear transformation between two images with different poses so as to make the transformed image best fits the other one. We integrate OPP into the regression model and propose the orthogonal Procrustes regression (OPR) model. To address the problem that the linear transformation is not suitable for handling highly non-linear pose variation, we further adopt a progressive strategy and propose the stacked OPR. As a practical framework, OPR can handle face alignment, pose correction, and face representation simultaneously. We optimize the proposed model via an efficient alternating iterative algorithm, and experimental results on three popular face databases, such as CMU PIE database, CMU Multi-PIE database, and LFW database, demonstrate the effectiveness of our proposed method.

  19. To Strike a Pose: No Stereotype Backlash for Power Posing Women.

    PubMed

    Rennung, Miriam; Blum, Johannes; Göritz, Anja S

    2016-01-01

    Power posing, the adoption of open and powerful postures, has effects that parallel those of actual social power. This study explored the social evaluation of adopting powerful vs. powerless body postures in men and women regarding perceived warmth, competence, and the likelihood of eliciting admiration, envy, pity, and contempt. Previous findings suggest that the display of power by women may have side effects due to gender stereotyping, namely reduced warmth ratings and negative emotional reactions. An experiment (N = 2,473) asked participants to rate pictures of men and women who adopted high-power or low-power body postures. High-power posers were rated higher on competence, admiration, envy, and contempt compared to low-power posers, whereas the opposite was true for pity. There was no impact of power posing on perceived warmth. Contrary to expectations, the poser's gender did not moderate any of the effects. These findings suggest that non-verbal displays of power do influence fundamental dimensions of social perception and their accompanying emotional reactions but result in comparably positive and negative evaluations for both genders.

  20. To Strike a Pose: No Stereotype Backlash for Power Posing Women

    PubMed Central

    Rennung, Miriam; Blum, Johannes; Göritz, Anja S.

    2016-01-01

    Power posing, the adoption of open and powerful postures, has effects that parallel those of actual social power. This study explored the social evaluation of adopting powerful vs. powerless body postures in men and women regarding perceived warmth, competence, and the likelihood of eliciting admiration, envy, pity, and contempt. Previous findings suggest that the display of power by women may have side effects due to gender stereotyping, namely reduced warmth ratings and negative emotional reactions. An experiment (N = 2,473) asked participants to rate pictures of men and women who adopted high-power or low-power body postures. High-power posers were rated higher on competence, admiration, envy, and contempt compared to low-power posers, whereas the opposite was true for pity. There was no impact of power posing on perceived warmth. Contrary to expectations, the poser’s gender did not moderate any of the effects. These findings suggest that non-verbal displays of power do influence fundamental dimensions of social perception and their accompanying emotional reactions but result in comparably positive and negative evaluations for both genders. PMID:27729887

  1. Head pose estimation algorithm based on deep learning

    NASA Astrophysics Data System (ADS)

    Cao, Yuanming; Liu, Yijun

    2017-05-01

    Head pose estimation has been widely used in the field of artificial intelligence, pattern recognition and intelligent human-computer interaction and so on. Good head pose estimation algorithm should deal with light, noise, identity, shelter and other factors robustly, but so far how to improve the accuracy and robustness of attitude estimation remains a major challenge in the field of computer vision. A method based on deep learning for pose estimation is presented. Deep learning with a strong learning ability, it can extract high-level image features of the input image by through a series of non-linear operation, then classifying the input image using the extracted feature. Such characteristics have greater differences in pose, while they are robust of light, identity, occlusion and other factors. The proposed head pose estimation is evaluated on the CAS-PEAL data set. Experimental results show that this method is effective to improve the accuracy of pose estimation.

  2. Making faces: posed facial expression, self-competence, and personality.

    PubMed

    Browne, B A

    1994-03-01

    This study examined the relationships between posed facial expression, childrens' perceived self-competence, and teachers' perceptions of competence. Third- and fifth-grade children completed the Self-Perception Profile for Children, the Eysenck Personality Questionnaire, and the Junior Self-Monitoring Scale for Children. Individual differences in posing accuracy were determined with a videotaped acting task. Children who were more able to produce prototypical expressions obtained higher teacher ratings of academic competence; however, posing ability bore little relationship to children's self-competence. Gender differences in feelings of self-competence, but not in sending ability, were observed. Extraversion and self-monitoring were unrelated to ability to pose emotional expressions.

  3. The lighter side of advertising: investigating posing and lighting biases.

    PubMed

    Thomas, Nicole A; Burkitt, Jennifer A; Patrick, Regan E; Elias, Lorin J

    2008-11-01

    People tend to display the left cheek when posing for a portrait; however, this effect does not appear to generalise to advertising. The amount of body visible in the image and the sex of the poser might also contribute to the posing bias. Portraits also exhibit lateral lighting biases, with most images being lit from the left. This effect might also be present in advertisements. A total of 2801 full-page advertisements were sampled and coded for posing direction, lighting direction, sex of model, and amount of body showing. Images of females showed an overall leftward posing bias, but the biases in males depended on the amount of body visible. Males demonstrated rightward posing biases for head-only images. Overall, images tended to be lit from the top left corner. The two factors of posing and lighting biases appear to influence one another. Leftward-lit images had more leftward poses than rightward, while the opposite occurred for rightward-lit images. Collectively, these results demonstrate that the posing biases in advertisements are dependent on the amount of body showing in the image, and that biases in lighting direction interact with these posing biases.

  4. Motor biases do not influence posing orientation in selfies.

    PubMed

    Lindell, Annukka K

    2017-01-01

    When posing for portraits people tend to offer their left cheek. This bias is also evident in selfies: informal photographic self-portraits taken with a smartphone. Mechanical biases have been argued to influence selfie posing orientation (predicting that using the left hand favours a stronger left cheek bias), however this hypothesis has not been directly tested. The present study was thus designed to determine whether motor biases influence selfie pose orientation. Three hundred and twenty participants (F = 159, M = 161) were asked to pose for a selfie "as you really are," and completed a handedness measure; hand used to take the selfie and selfie pose orientation were recorded. Ordinal logistic regression confirmed that neither participant handedness nor hand used to capture the selfie predicted selfie pose orientation. Regardless of sex, handedness, or hand used, participants were more likely to present a midline (49.75%) than a left (26.53%) or right (26.72%) cheek pose. Though handedness was a strong predictor of hand used to capture the selfie (left handers favour the left, and right handers the right, hand), it did not predict posing orientation. These results confirm that selfie cheek biases are not simply a residual effect of the mechanics of taking selfies.

  5. Binding Pose Flip Explained via Enthalpic and Entropic Contributions

    PubMed Central

    2017-01-01

    The anomalous binding modes of five highly similar fragments of TIE2 inhibitors, showing three distinct binding poses, are investigated. We report a quantitative rationalization for the changes in binding pose based on molecular dynamics simulations. We investigated five fragments in complex with the transforming growth factor β receptor type 1 kinase domain. Analyses of these simulations using Grid Inhomogeneous Solvation Theory (GIST), pKA calculations, and a tool to investigate enthalpic differences upon binding unraveled the various thermodynamic contributions to the different binding modes. While one binding mode flip can be rationalized by steric repulsion, the second binding pose flip revealed a different protonation state for one of the ligands, leading to different enthalpic and entropic contributions to the binding free energy. One binding pose is stabilized by the displacement of entropically unfavored water molecules (binding pose determined by solvation entropy), ligands in the other binding pose are stabilized by strong enthalpic interactions, overcompensating the unfavorable water entropy in this pose (binding pose determined by enthalpic interactions). This analysis elucidates unprecedented details determining the flipping of the binding modes, which can elegantly explain the experimental findings for this system. PMID:28079371

  6. A Survey on Model Based Approaches for 2D and 3D Visual Human Pose Recovery

    PubMed Central

    Perez-Sala, Xavier; Escalera, Sergio; Angulo, Cecilio; Gonzàlez, Jordi

    2014-01-01

    Human Pose Recovery has been studied in the field of Computer Vision for the last 40 years. Several approaches have been reported, and significant improvements have been obtained in both data representation and model design. However, the problem of Human Pose Recovery in uncontrolled environments is far from being solved. In this paper, we define a general taxonomy to group model based approaches for Human Pose Recovery, which is composed of five main modules: appearance, viewpoint, spatial relations, temporal consistence, and behavior. Subsequently, a methodological comparison is performed following the proposed taxonomy, evaluating current SoA approaches in the aforementioned five group categories. As a result of this comparison, we discuss the main advantages and drawbacks of the reviewed literature. PMID:24594613

  7. A survey on model based approaches for 2D and 3D visual human pose recovery.

    PubMed

    Perez-Sala, Xavier; Escalera, Sergio; Angulo, Cecilio; Gonzàlez, Jordi

    2014-03-03

    Human Pose Recovery has been studied in the field of Computer Vision for the last 40 years. Several approaches have been reported, and significant improvements have been obtained in both data representation and model design. However, the problem of Human Pose Recovery in uncontrolled environments is far from being solved. In this paper, we define a general taxonomy to group model based approaches for Human Pose Recovery, which is composed of five main modules: appearance, viewpoint, spatial relations, temporal consistence, and behavior. Subsequently, a methodological comparison is performed following the proposed taxonomy, evaluating current SoA approaches in the aforementioned five group categories. As a result of this comparison, we discuss the main advantages and drawbacks of the reviewed literature.

  8. Generalized Hough transform based time invariant action recognition with 3D pose information

    NASA Astrophysics Data System (ADS)

    Muench, David; Huebner, Wolfgang; Arens, Michael

    2014-10-01

    Human action recognition has emerged as an important field in the computer vision community due to its large number of applications such as automatic video surveillance, content based video-search and human robot interaction. In order to cope with the challenges that this large variety of applications present, recent research has focused more on developing classifiers able to detect several actions in more natural and unconstrained video sequences. The invariance discrimination tradeoff in action recognition has been addressed by utilizing a Generalized Hough Transform. As a basis for action representation we transform 3D poses into a robust feature space, referred to as pose descriptors. For each action class a one-dimensional temporal voting space is constructed. Votes are generated from associating pose descriptors with their position in time relative to the end of an action sequence. Training data consists of manually segmented action sequences. In the detection phase valid human 3D poses are assumed as input, e.g. originating from 3D sensors or monocular pose reconstruction methods. The human 3D poses are normalized to gain view-independence and transformed into (i) relative limb-angle space to ensure independence of non-adjacent joints or (ii) geometric features. In (i) an action descriptor consists of the relative angles between limbs and their temporal derivatives. In (ii) the action descriptor consists of different geometric features. In order to circumvent the problem of time-warping we propose to use a codebook of prototypical 3D poses which is generated from sample sequences of 3D motion capture data. This idea is in accordance with the concept of equivalence classes in action space. Results of the codebook method are presented using the Kinect sensor and the CMU Motion Capture Database.

  9. Counterfeit phosphodiesterase type 5 inhibitors pose significant safety risks

    PubMed Central

    Jackson, G; Arver, S; Banks, I; Stecher, V J

    2010-01-01

    Counterfeit drugs are inherently dangerous and a growing problem; counterfeiters are becoming increasingly sophisticated. Growth of the counterfeit medication market is attributable in part to phosphodiesterase type 5 inhibitor (PDE5i) medications for erectile dysfunction (ED). Millions of counterfeit PDE5is are seized yearly and account for the bulk of all counterfeit pharmaceutical product seizures. It has been estimated that up to 2.5 million men in Europe are exposed to illicit sildenafil, suggesting that there may be as many illegal as legal users of sildenafil. Analysis of the contents of counterfeit PDE5is shows inconsistent doses of active pharmaceutical ingredients (from 0% to > 200% of labelled dose), contaminants (including talcum powder, commercial paint and printer ink) and alternative ingredients that are potentially hazardous. In one analysis, only 10.1% of samples were within 10% of the labelled tablet strength. Estimates place the proportion of counterfeit medications sold over the Internet from 44% to 90%. Of men who purchase prescription-only medication for ED without a prescription, 67% do so using the Internet. Counterfeit PDE5is pose direct and indirect risks to health, including circumvention of the healthcare system. More than 30% of men reported no healthcare interaction when purchasing ED medications. Because > 65% actually had ED, these men missed an opportunity for evaluation of comorbidities (e.g. diabetes and hypertension). Globally, increased obstacles for counterfeiters are necessary to combat pharmaceutical counterfeiting, including fines and penalties. The worldwide nature of the counterfeit problem requires proper coordination between countries to ensure adequate enforcement. Locally, physicians who treat ED need to inform patients of the dangers of ordering PDE5is via the Internet. PMID:20088883

  10. A Bayesian Framework for Human Body Pose Tracking from Depth Image Sequences

    PubMed Central

    Zhu, Youding; Fujimura, Kikuo

    2010-01-01

    This paper addresses the problem of accurate and robust tracking of 3D human body pose from depth image sequences. Recovering the large number of degrees of freedom in human body movements from a depth image sequence is challenging due to the need to resolve the depth ambiguity caused by self-occlusions and the difficulty to recover from tracking failure. Human body poses could be estimated through model fitting using dense correspondences between depth data and an articulated human model (local optimization method). Although it usually achieves a high accuracy due to dense correspondences, it may fail to recover from tracking failure. Alternately, human pose may be reconstructed by detecting and tracking human body anatomical landmarks (key-points) based on low-level depth image analysis. While this method (key-point based method) is robust and recovers from tracking failure, its pose estimation accuracy depends solely on image-based localization accuracy of key-points. To address these limitations, we present a flexible Bayesian framework for integrating pose estimation results obtained by methods based on key-points and local optimization. Experimental results are shown and performance comparison is presented to demonstrate the effectiveness of the proposed approach. PMID:22399933

  11. A Bayesian framework for human body pose tracking from depth image sequences.

    PubMed

    Zhu, Youding; Fujimura, Kikuo

    2010-01-01

    This paper addresses the problem of accurate and robust tracking of 3D human body pose from depth image sequences. Recovering the large number of degrees of freedom in human body movements from a depth image sequence is challenging due to the need to resolve the depth ambiguity caused by self-occlusions and the difficulty to recover from tracking failure. Human body poses could be estimated through model fitting using dense correspondences between depth data and an articulated human model (local optimization method). Although it usually achieves a high accuracy due to dense correspondences, it may fail to recover from tracking failure. Alternately, human pose may be reconstructed by detecting and tracking human body anatomical landmarks (key-points) based on low-level depth image analysis. While this method (key-point based method) is robust and recovers from tracking failure, its pose estimation accuracy depends solely on image-based localization accuracy of key-points. To address these limitations, we present a flexible Bayesian framework for integrating pose estimation results obtained by methods based on key-points and local optimization. Experimental results are shown and performance comparison is presented to demonstrate the effectiveness of the proposed approach.

  12. Quaternion epipolar decomposition for camera pose identification and animation

    NASA Astrophysics Data System (ADS)

    Skarbek, W.; Tomaszewski, M.

    2013-03-01

    In the literature of computer vision, computer graphics and robotics, the use of quaternions is exclusively related to 3D rotation representation and interpolation. In this research we found how epipoles in multi-camera systems can be used to represent camera poses in the quaternion domain. The rotational quaternion is decomposed in two epipole rotational quaternions and one z axis rotational quaternion. Quadratic form of the essential matrix is also related to quaternion factors. Thus, five pose parameters are distributed into three independent rotational quaternions resulting in measurement error separation at camera pose identification and greater flexibility at virtual camera animation. The experimental results refer to the design of free viewpoint television.

  13. Pose-free structure from motion using depth from motion constraints.

    PubMed

    Zhang, Ji; Boutin, Mireille; Aliaga, Daniel G

    2011-10-01

    Structure from motion (SFM) is the problem of recovering the geometry of a scene from a stream of images taken from unknown viewpoints. One popular approach to estimate the geometry of a scene is to track scene features on several images and reconstruct their position in 3-D. During this process, the unknown camera pose must also be recovered. Unfortunately, recovering the pose can be an ill-conditioned problem which, in turn, can make the SFM problem difficult to solve accurately. We propose an alternative formulation of the SFM problem with fixed internal camera parameters known a priori. In this formulation, obtained by algebraic variable elimination, the external camera pose parameters do not appear. As a result, the problem is better conditioned in addition to involving much fewer variables. Variable elimination is done in three steps. First, we take the standard SFM equations in projective coordinates and eliminate the camera orientations from the equations. We then further eliminate the camera center positions. Finally, we also eliminate all 3-D point positions coordinates, except for their depths with respect to the camera center, thus obtaining a set of simple polynomial equations of degree two and three. We show that, when there are merely a few points and pictures, these "depth-only equations" can be solved in a global fashion using homotopy methods. We also show that, in general, these same equations can be used to formulate a pose-free cost function to refine SFM solutions in a way that is more accurate than by minimizing the total reprojection error, as done when using the bundle adjustment method. The generalization of our approach to the case of varying internal camera parameters is briefly discussed.

  14. Fringe inverse videogrammetry based on global pose estimation.

    PubMed

    Xiao, Yong-Liang; Su, Xianyu; Chen, Wenjing

    2011-10-10

    Fringe inverse videogrammetry based on global pose estimation is presented to measure a three-dimensional (3D) coordinate. The main components involve an LCD screen, a tactile probe equipped with a microcamera, and a portable personal computer. The LCD is utilized to display fringes, a microcamera is installed on the tactile probe, and the 3D coordinate of the center of the probe tip can be calculated through the microcamera's pose. Fourier fringe analysis is exploited to complete subpixel location of reference points. A convex-relaxation optimization algorithm is employed to estimate the global camera pose, which guarantees global convergence compared with bundle adjustment, a local pose estimation algorithm. The experiments demonstrate that fringe inverse videogrammetry can measure the 3D coordinate precisely. © 2011 Optical Society of America

  15. Space vehicle pose estimation via optical correlation and nonlinear estimation

    NASA Astrophysics Data System (ADS)

    Rakoczy, John M.; Herren, Kenneth A.

    2008-03-01

    A technique for 6-degree-of-freedom (6DOF) pose estimation of space vehicles is being developed. This technique draws upon recent developments in implementing optical correlation measurements in a nonlinear estimator, which relates the optical correlation measurements to the pose states (orientation and position). For the optical correlator, the use of both conjugate filters and binary, phase-only filters in the design of synthetic discriminant function (SDF) filters is explored. A static neural network is trained a priori and used as the nonlinear estimator. New commercial animation and image rendering software is exploited to design the SDF filters and to generate a large filter set with which to train the neural network. The technique is applied to pose estimation for rendezvous and docking of free-flying spacecraft and to terrestrial surface mobility systems for NASA's Vision for Space Exploration. Quantitative pose estimation performance will be reported. Advantages and disadvantages of the implementation of this technique are discussed.

  16. Space Vehicle Pose Estimation via Optical Correlation and Nonlinear Estimation

    NASA Technical Reports Server (NTRS)

    Rakoczy, John; Herren, Kenneth

    2007-01-01

    A technique for 6-degree-of-freedom (6DOF) pose estimation of space vehicles is being developed. This technique draws upon recent developments in implementing optical correlation measurements in a nonlinear estimator, which relates the optical correlation measurements to the pose states (orientation and position). For the optical correlator, the use of both conjugate filters and binary, phase-only filters in the design of synthetic discriminant function (SDF) filters is explored. A static neural network is trained a priori and used as the nonlinear estimator. New commercial animation and image rendering software is exploited to design the SDF filters and to generate a large filter set with which to train the neural network. The technique is applied to pose estimation for rendezvous and docking of free-flying spacecraft and to terrestrial surface mobility systems for NASA's Vision for Space Exploration. Quantitative pose estimation performance will be reported. Advantages and disadvantages of the implementation of this technique are discussed.

  17. Space Vehicle Pose Estimation via Optical Correlation and Nonlinear Estimation

    NASA Technical Reports Server (NTRS)

    Rakoczy, John M.; Herren, Kenneth A.

    2008-01-01

    A technique for 6-degree-of-freedom (6DOF) pose estimation of space vehicles is being developed. This technique draws upon recent developments in implementing optical correlation measurements in a nonlinear estimator, which relates the optical correlation measurements to the pose states (orientation and position). For the optical correlator, the use of both conjugate filters and binary, phase-only filters in the design of synthetic discriminant function (SDF) filters is explored. A static neural network is trained a priori and used as the nonlinear estimator. New commercial animation and image rendering software is exploited to design the SDF filters and to generate a large filter set with which to train the neural network. The technique is applied to pose estimation for rendezvous and docking of free-flying spacecraft and to terrestrial surface mobility systems for NASA's Vision for Space Exploration. Quantitative pose estimation performance will be reported. Advantages and disadvantages of the implementation of this technique are discussed.

  18. 32. BUCKET POSING OVER CARGO HOLD; NOTE OPERATOR OVER BUCKET. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. BUCKET POSING OVER CARGO HOLD; NOTE OPERATOR OVER BUCKET. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  19. 11. Photocopied July 1978. (QMC) GROUP SHOT OF WORKERS POSED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Photocopied July 1978. (QMC) GROUP SHOT OF WORKERS POSED WITH NO. 2 SHAFT-ROCKHOUSE IN BACKGROUND. NOTE THE LONE WOMAN IN THE PHOTO. C. 1895-1905. - Quincy Mining Company, Hancock, Houghton County, MI

  20. Are predefined decoy sets of ligand poses able to quantify scoring function accuracy?

    NASA Astrophysics Data System (ADS)

    Korb, Oliver; ten Brink, Tim; Victor Paul Raj, Fredrick Robin Devadoss; Keil, Matthias; Exner, Thomas E.

    2012-02-01

    Due to the large number of different docking programs and scoring functions available, researchers are faced with the problem of selecting the most suitable one when starting a structure-based drug discovery project. To guide the decision process, several studies comparing different docking and scoring approaches have been published. In the context of comparing scoring function performance, it is common practice to use a predefined, computer-generated set of ligand poses (decoys) and to reevaluate their score using the set of scoring functions to be compared. But are predefined decoy sets able to unambiguously evaluate and rank different scoring functions with respect to pose prediction performance? This question arose when the pose prediction performance of our piecewise linear potential derived scoring functions (Korb et al. in J Chem Inf Model 49:84-96, 2009) was assessed on a standard decoy set (Cheng et al. in J Chem Inf Model 49:1079-1093, 2009). While they showed excellent pose identification performance when they were used for rescoring of the predefined decoy conformations, a pronounced degradation in performance could be observed when they were directly applied in docking calculations using the same test set. This implies that on a discrete set of ligand poses only the rescoring performance can be evaluated. For comparing the pose prediction performance in a more rigorous manner, the search space of each scoring function has to be sampled extensively as done in the docking calculations performed here. We were able to identify relative strengths and weaknesses of three scoring functions (ChemPLP, GoldScore, and Astex Statistical Potential) by analyzing the performance for subsets of the complexes grouped by different properties of the active site. However, reasons for the overall poor performance of all three functions on this test set compared to other test sets of similar size could not be identified.

  1. Joint albedo estimation and pose tracking from video.

    PubMed

    Taheri, Sima; Sankaranarayanan, Aswin C; Chellappa, Rama

    2013-07-01

    The albedo of a Lambertian object is a surface property that contributes to an object's appearance under changing illumination. As a signature independent of illumination, the albedo is useful for object recognition. Single image-based albedo estimation algorithms suffer due to shadows and non-Lambertian effects of the image. In this paper, we propose a sequential algorithm to estimate the albedo from a sequence of images of a known 3D object in varying poses and illumination conditions. We first show that by knowing/estimating the pose of the object at each frame of a sequence, the object's albedo can be efficiently estimated using a Kalman filter. We then extend this for the case of unknown pose by simultaneously tracking the pose as well as updating the albedo through a Rao-Blackwellized particle filter (RBPF). More specifically, the albedo is marginalized from the posterior distribution and estimated analytically using the Kalman filter, while the pose parameters are estimated using importance sampling and by minimizing the projection error of the face onto its spherical harmonic subspace, which results in an illumination-insensitive pose tracking algorithm. Illustrations and experiments are provided to validate the effectiveness of the approach using various synthetic and real sequences followed by applications to unconstrained, video-based face recognition.

  2. Multi-object segmentation using coupled nonparametric shape and relative pose priors

    NASA Astrophysics Data System (ADS)

    Uzunbas, Mustafa Gökhan; Soldea, Octavian; Çetin, Müjdat; Ünal, Gözde; Erçil, Aytül; Unay, Devrim; Ekin, Ahmet; Firat, Zeynep

    2009-02-01

    We present a new method for multi-object segmentation in a maximum a posteriori estimation framework. Our method is motivated by the observation that neighboring or coupling objects in images generate configurations and co-dependencies which could potentially aid in segmentation if properly exploited. Our approach employs coupled shape and inter-shape pose priors that are computed using training images in a nonparametric multi-variate kernel density estimation framework. The coupled shape prior is obtained by estimating the joint shape distribution of multiple objects and the inter-shape pose priors are modeled via standard moments. Based on such statistical models, we formulate an optimization problem for segmentation, which we solve by an algorithm based on active contours. Our technique provides significant improvements in the segmentation of weakly contrasted objects in a number of applications. In particular for medical image analysis, we use our method to extract brain Basal Ganglia structures, which are members of a complex multi-object system posing a challenging segmentation problem. We also apply our technique to the problem of handwritten character segmentation. Finally, we use our method to segment cars in urban scenes.

  3. Optimal accelerometer placement on a robot arm for pose estimation

    NASA Astrophysics Data System (ADS)

    Wijayasinghe, Indika B.; Sanford, Joseph D.; Abubakar, Shamsudeen; Saadatzi, Mohammad Nasser; Das, Sumit K.; Popa, Dan O.

    2017-05-01

    The performance of robots to carry out tasks depends in part on the sensor information they can utilize. Usually, robots are fitted with angle joint encoders that are used to estimate the position and orientation (or the pose) of its end-effector. However, there are numerous situations, such as in legged locomotion, mobile manipulation, or prosthetics, where such joint sensors may not be present at every, or any joint. In this paper we study the use of inertial sensors, in particular accelerometers, placed on the robot that can be used to estimate the robot pose. Studying accelerometer placement on a robot involves many parameters that affect the performance of the intended positioning task. Parameters such as the number of accelerometers, their size, geometric placement and Signal-to-Noise Ratio (SNR) are included in our study of their effects for robot pose estimation. Due to the ubiquitous availability of inexpensive accelerometers, we investigated pose estimation gains resulting from using increasingly large numbers of sensors. Monte-Carlo simulations are performed with a two-link robot arm to obtain the expected value of an estimation error metric for different accelerometer configurations, which are then compared for optimization. Results show that, with a fixed SNR model, the pose estimation error decreases with increasing number of accelerometers, whereas for a SNR model that scales inversely to the accelerometer footprint, the pose estimation error increases with the number of accelerometers. It is also shown that the optimal placement of the accelerometers depends on the method used for pose estimation. The findings suggest that an integration-based method favors placement of accelerometers at the extremities of the robot links, whereas a kinematic-constraints-based method favors a more uniformly distributed placement along the robot links.

  4. Particle Filters and Occlusion Handling for Rigid 2D-3D Pose Tracking

    PubMed Central

    Lee, Jehoon; Sandhu, Romeil; Tannenbaum, Allen

    2013-01-01

    In this paper, we address the problem of 2D-3D pose estimation. Specifically, we propose an approach to jointly track a rigid object in a 2D image sequence and to estimate its pose (position and orientation) in 3D space. We revisit a joint 2D segmentation/3D pose estimation technique, and then extend the framework by incorporating a particle filter to robustly track the object in a challenging environment, and by developing an occlusion detection and handling scheme to continuously track the object in the presence of occlusions. In particular, we focus on partial occlusions that prevent the tracker from extracting an exact region properties of the object, which plays a pivotal role for region-based tracking methods in maintaining the track. To this end, a dynamical choice of how to invoke the objective functional is performed online based on the degree of dependencies between predictions and measurements of the system in accordance with the degree of occlusion and the variation of the object’s pose. This scheme provides the robustness to deal with occlusions of an obstacle with different statistical properties from that of the object of interest. Experimental results demonstrate the practical applicability and robustness of the proposed method in several challenging scenarios. PMID:24058277

  5. Surgical fiducial segmentation and tracking for pose estimation based on ultrasound B-mode images.

    PubMed

    Lei Chen; Kuo, Nathanael; Aalamifar, Fereshteh; Narrow, David; Coon, Devin; Prince, Jerry; Boctor, Emad M

    2016-08-01

    Doppler ultrasound is a non-invasive diagnostic tool for the quantitative measurement of blood flow. However, given that it provides velocity data that is dependent on the location and angle of measurement, repeat measurements to detect problems over time may require an expert to return to the same location. We therefore developed an image-guidance system based on ultrasound B-mode images that enables an inexperienced user to position the ultrasound probe at the same site repeatedly in order to acquire a comparable time series of Doppler readings. The system utilizes a bioresorbable fiducial and complementing software composed of the fiducial detection, key points tracking, probe pose estimation, and graphical user interface (GUI) modules. The fiducial is an echogenic marker that is implanted at the surgical site and can be detected and tracked during ultrasound B-mode screening. The key points on the marker can next be used to determine the pose of the ultrasound probe with respect to the marker. The 3D representation of the probe with its position and orientation are then displayed in the GUI for the user guidance. The fiducial detection has been tested on the data sets collected from three animal studies. The pose estimation algorithm was validated by five data sets collected by a UR5 robot. We tested the system on a plastisol phantom and showed that it can detect and track the fiducial marker while displaying the probe pose in real-time.

  6. Effects of protein conformation in docking: improved pose prediction through protein pocket adaptation

    NASA Astrophysics Data System (ADS)

    Jain, Ajay N.

    2009-06-01

    Computational methods for docking ligands have been shown to be remarkably dependent on precise protein conformation, where acceptable results in pose prediction have been generally possible only in the artificial case of re-docking a ligand into a protein binding site whose conformation was determined in the presence of the same ligand (the "cognate" docking problem). In such cases, on well curated protein/ligand complexes, accurate dockings can be returned as top-scoring over 75% of the time using tools such as Surflex-Dock. A critical application of docking in modeling for lead optimization requires accurate pose prediction for novel ligands, ranging from simple synthetic analogs to very different molecular scaffolds. Typical results for widely used programs in the "cross-docking case" (making use of a single fixed protein conformation) have rates closer to 20% success. By making use of protein conformations from multiple complexes, Surflex-Dock yields an average success rate of 61% across eight pharmaceutically relevant targets. Following docking, protein pocket adaptation and rescoring identifies single pose families that are correct an average of 67% of the time. Consideration of the best of two pose families (from alternate scoring regimes) yields a 75% mean success rate.

  7. Effects of protein conformation in docking: improved pose prediction through protein pocket adaptation.

    PubMed

    Jain, Ajay N

    2009-06-01

    Computational methods for docking ligands have been shown to be remarkably dependent on precise protein conformation, where acceptable results in pose prediction have been generally possible only in the artificial case of re-docking a ligand into a protein binding site whose conformation was determined in the presence of the same ligand (the "cognate" docking problem). In such cases, on well curated protein/ligand complexes, accurate dockings can be returned as top-scoring over 75% of the time using tools such as Surflex-Dock. A critical application of docking in modeling for lead optimization requires accurate pose prediction for novel ligands, ranging from simple synthetic analogs to very different molecular scaffolds. Typical results for widely used programs in the "cross-docking case" (making use of a single fixed protein conformation) have rates closer to 20% success. By making use of protein conformations from multiple complexes, Surflex-Dock yields an average success rate of 61% across eight pharmaceutically relevant targets. Following docking, protein pocket adaptation and rescoring identifies single pose families that are correct an average of 67% of the time. Consideration of the best of two pose families (from alternate scoring regimes) yields a 75% mean success rate.

  8. Recognition of 3D facial expression from posed data

    NASA Astrophysics Data System (ADS)

    Samad, Manar D.; Iftekharuddin, Khan M.

    2013-05-01

    Although recognition of facial expression in 3D facial images has been an active research area, most of the prior works are limited to using full frontal facial images. These techniques primarily project 3D facial image on 2D and manually select landmarks in 2D projection to extract relevant features. Face recognition in 2D images can be challenging due to unconstrained conditions such as head pose, occlusion, and resulting loss of data. Similarly, pose variation in 3D facial imaging can also result in loss of data. In most of the current 3D facial recognition works, when 3D posed face data are projected onto 2D, additional data loss may render 2D facial expression recognition even more challenging. In comparison, this work proposes novel feature extraction directly from the 3D facial posed images without the need of manual selection of landmarks or projection of images in 2D space. This feature is obtained as the angle between consecutive 3D normal vectors on the vertex points aligned either horizontally or vertically across the 3D facial image. Our facial expression recognition results show that the feature obtained from vertices aligned vertically across the face yields the best accuracy for classification with an average 87.8% area under the ROC. The results further suggest that the same feature outperforms its horizontal counterpart in recognizing facial expressions for pose variation between 35º - 50º with average accuracy of 80% - 60%, respectively.

  9. Preparatory power posing affects nonverbal presence and job interview performance.

    PubMed

    Cuddy, Amy J C; Wilmuth, Caroline A; Yap, Andy J; Carney, Dana R

    2015-07-01

    The authors tested whether engaging in expansive (vs. contractive) "power poses" before a stressful job interview--preparatory power posing--would enhance performance during the interview. Participants adopted high-power (i.e., expansive, open) poses or low-power (i.e., contractive, closed) poses, and then prepared and delivered a speech to 2 evaluators as part of a mock job interview. All interview speeches were videotaped and coded for overall performance and hireability and for 2 potential mediators: verbal content (e.g., structure, content) and nonverbal presence (e.g., captivating, enthusiastic). As predicted, those who prepared for the job interview with high- (vs. low-) power poses performed better and were more likely to be chosen for hire; this relation was mediated by nonverbal presence, but not by verbal content. Although previous research has focused on how a nonverbal behavior that is enacted during interactions and observed by perceivers affects how those perceivers evaluate and respond to the actor, this experiment focused on how a nonverbal behavior that is enacted before the interaction and unobserved by perceivers affects the actor's performance, which, in turn, affects how perceivers evaluate and respond to the actor. This experiment reveals a theoretically novel and practically informative result that demonstrates the causal relation between preparatory nonverbal behavior and subsequent performance and outcomes.

  10. Learning a Tracking and Estimation Integrated Graphical Model for Human Pose Tracking.

    PubMed

    Zhao, Lin; Gao, Xinbo; Tao, Dacheng; Li, Xuelong

    2015-12-01

    We investigate the tracking of 2-D human poses in a video stream to determine the spatial configuration of body parts in each frame, but this is not a trivial task because people may wear different kinds of clothing and may move very quickly and unpredictably. The technology of pose estimation is typically applied, but it ignores the temporal context and cannot provide smooth, reliable tracking results. Therefore, we develop a tracking and estimation integrated model (TEIM) to fully exploit temporal information by integrating pose estimation with visual tracking. However, joint parsing of multiple articulated parts over time is difficult, because a full model with edges capturing all pairwise relationships within and between frames is loopy and intractable. In previous models, approximate inference was usually resorted to, but it cannot promise good results and the computational cost is large. We overcome these problems by exploring the idea of divide and conquer, which decomposes the full model into two much simpler tractable submodels. In addition, a novel two-step iteration strategy is proposed to efficiently conquer the joint parsing problem. Algorithmically, we design TEIM very carefully so that: 1) it enables pose estimation and visual tracking to compensate for each other to achieve desirable tracking results; 2) it is able to deal with the problem of tracking loss; and 3) it only needs past information and is capable of tracking online. Experiments are conducted on two public data sets in the wild with ground truth layout annotations, and the experimental results indicate the effectiveness of the proposed TEIM framework.

  11. Vision based object pose estimation for mobile robots

    NASA Technical Reports Server (NTRS)

    Wu, Annie; Bidlack, Clint; Katkere, Arun; Feague, Roy; Weymouth, Terry

    1994-01-01

    Mobile robot navigation using visual sensors requires that a robot be able to detect landmarks and obtain pose information from a camera image. This paper presents a vision system for finding man-made markers of known size and calculating the pose of these markers. The algorithm detects and identifies the markers using a weighted pattern matching template. Geometric constraints are then used to calculate the position of the markers relative to the robot. The selection of geometric constraints comes from the typical pose of most man-made signs, such as the sign standing vertical and the dimensions of known size. This system has been tested successfully on a wide range of real images. Marker detection is reliable, even in cluttered environments, and under certain marker orientations, estimation of the orientation has proven accurate to within 2 degrees, and distance estimation to within 0.3 meters.

  12. Viewpoint and pose in body-form adaptation.

    PubMed

    Sekunova, Alla; Black, Michael; Parkinson, Laura; Barton, Jason J S

    2013-01-01

    Faces and bodies are complex structures, perception of which can play important roles in person identification and inference of emotional state. Face representations have been explored using behavioural adaptation: in particular, studies have shown that face aftereffects show relatively broad tuning for viewpoint, consistent with origin in a high-level structural descriptor far removed from the retinal image. Our goals were to determine first, if body aftereffects also showed a degree of viewpoint invariance, and second if they also showed pose invariance, given that changes in pose create even more dramatic changes in the 2-D retinal image. We used a 3-D model of the human body to generate headless body images, whose parameters could be varied to generate different body forms, viewpoints, and poses. In the first experiment, subjects adapted to varying viewpoints of either slim or heavy bodies in a neutral stance, followed by test stimuli that were all front-facing. In the second experiment, we used the same front-facing bodies in neutral stance as test stimuli, but compared adaptation from bodies in the same neutral stance to adaptation with the same bodies in different poses. We found that body aftereffects were obtained over substantial viewpoint changes, with no significant decline in aftereffect magnitude with increasing viewpoint difference between adapting and test images. Aftereffects also showed transfer across one change in pose but not across another. We conclude that body representations may have more viewpoint invariance than faces, and demonstrate at least some transfer across pose, consistent with a high-level structural description.

  13. Pose Estimation from Line Correspondences: A Complete Analysis and A Series of Solutions.

    PubMed

    Xu, Chi; Zhang, Lilian; Cheng, Li; Koch, Reinhard

    2016-06-20

    In this paper we deal with the camera pose estimation problem from a set of 2D/3D line correspondences, which is also known as PnL (Perspective-n-Line) problem. We carry out our study by comparing PnL with the well-studied PnP (Perspective-n-Point) problem, and our contributions are threefold: (1) We provide a complete 3D configuration analysis for P3L, which includes the well-known P3P problem as well as several existing analyses as special cases. (2) By exploring the similarity between PnL and PnP, we propose a new subset-based PnL approach as well as a series of linear-formulation-based PnL approaches inspired by their PnP counterparts. (3) The proposed linear-formulation-based methods can be easily extended to deal with the line and point features simultaneously.

  14. Online Professors Pose as Students to Encourage Real Learning

    ERIC Educational Resources Information Center

    Parry, Marc

    2009-01-01

    Some professors of online courses are posing as students, infiltrating online course to collect information about students by blending in with them. The deceit has provoked questions about faculty ethics. Two professors admit that their unreal students teeter on an ethical precipice, because the technique could be abused. Others in the…

  15. Optical neural network system for pose determination of spinning satellites

    NASA Astrophysics Data System (ADS)

    Lee, Andrew J.; Casasent, David P.

    1990-09-01

    An optical neural network architecture and algorithm based on a Hopfield optimization network are presented for multitarget tracking. This tracker utilizes a neuron for every possible target track and a quadratic energy function of neural activities which is minimized using gradient descent neural evolution. The neural net tracker is demonstrated as part of a system for determining position and orientation (pose) of spinning sateffites with respect to a robotic spacecraft. The input to the system is time sequence video from a single camera. Novelty detection and filtering are utilized to locate and segment novel regions from the input images. The neural net multitarget tracker determines the correspondences (or tracks) of the novel regions as a function of time and hence the paths of object (sateffite) parts. The path traced out by a given part or region is approximately elliptical in image space and the position shape and orientation of the ellipse are functions of the satellite geometry and its pose. Having a geometric model of the satellite and the effiptical path of a part in image space the 3-D pose of the satellite is determined. Digital simulation results using this algorithm are presented for various sateffite poses and lighting conditions. 1

  16. Hadfield poses with MSL FLSS in the Node 2

    NASA Image and Video Library

    2012-12-23

    ISS034-E-010603 (28 Dec. 2012) --- Canadian Space Agency astronaut Chris Hadfield, Expedition 34 flight engineer, poses with a Materials Science Laboratory (MSL) Furnace Launch Support Structure (FLSS) in the Destiny laboratory of the International Space Station. NASA astronaut Tom Marshburn, flight engineer, uses a computer in the background.

  17. Hadfield poses with MSL FLSS in the Node 2

    NASA Image and Video Library

    2012-12-23

    View of Canada Space Agency (CSA) Chris Hadfield, Expedition 34 Flight Engineer (FE), poses with a Materials Science Laboratory (MSL) Furnace Launch Support Structure (FLSS) in the U.S. Laboratory. Tom Marshburn (background), Expedition 34 FE uses laptop computer. Photo was taken during Expedition 34.

  18. Lessons about Climate Change Pose Many Challenges for Science Teachers

    ERIC Educational Resources Information Center

    Cavanagh, Sean

    2007-01-01

    This article reports on lessons about climate change which pose many challenges for science teachers. The natural world today offers a broad--and dire--catalog of scientific phenomena for teachers wanting to craft classroom lessons on the topic of climate change. As public concern about global warming increases, teachers are carving out a larger…

  19. Optical neural network system for pose determination of spinning satellites

    NASA Technical Reports Server (NTRS)

    Lee, Andrew; Casasent, David

    1990-01-01

    An optical neural network architecture and algorithm based on a Hopfield optimization network are presented for multitarget tracking. This tracker utilizes a neuron for every possible target track, and a quadratic energy function of neural activities which is minimized using gradient descent neural evolution. The neural net tracker is demonstrated as part of a system for determining position and orientation (pose) of spinning satellites with respect to a robotic spacecraft. The input to the system is time sequence video from a single camera. Novelty detection and filtering are utilized to locate and segment novel regions from the input images. The neural net multitarget tracker determines the correspondences (or tracks) of the novel regions as a function of time, and hence the paths of object (satellite) parts. The path traced out by a given part or region is approximately elliptical in image space, and the position, shape and orientation of the ellipse are functions of the satellite geometry and its pose. Having a geometric model of the satellite, and the elliptical path of a part in image space, the three-dimensional pose of the satellite is determined. Digital simulation results using this algorithm are presented for various satellite poses and lighting conditions.

  20. 43. Historic photo of Bruce Lundin posing in front of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    43. Historic photo of Bruce Lundin posing in front of observation window in exhaust cone at base of test stand A in Building 202, September 1960. On file at NASA Plumbrook Research Center, Sandusky, Ohio. NASA photo number C-53170. - Rocket Engine Testing Facility, GRC Building No. 202, NASA Glenn Research Center, Cleveland, Cuyahoga County, OH

  1. Child Deaths Highlight Choking Dangers Posed by Grapes

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_162679.html Child Deaths Highlight Choking Dangers Posed by Grapes Deaths of 5-year-old and toddler cited in ... 2016 (HealthDay News) -- Young children can choke to death on whole grapes, warn the authors of a ...

  2. Optical neural network system for pose determination of spinning satellites

    NASA Technical Reports Server (NTRS)

    Lee, Andrew; Casasent, David

    1990-01-01

    An optical neural network architecture and algorithm based on a Hopfield optimization network are presented for multitarget tracking. This tracker utilizes a neuron for every possible target track, and a quadratic energy function of neural activities which is minimized using gradient descent neural evolution. The neural net tracker is demonstrated as part of a system for determining position and orientation (pose) of spinning satellites with respect to a robotic spacecraft. The input to the system is time sequence video from a single camera. Novelty detection and filtering are utilized to locate and segment novel regions from the input images. The neural net multitarget tracker determines the correspondences (or tracks) of the novel regions as a function of time, and hence the paths of object (satellite) parts. The path traced out by a given part or region is approximately elliptical in image space, and the position, shape and orientation of the ellipse are functions of the satellite geometry and its pose. Having a geometric model of the satellite, and the elliptical path of a part in image space, the three-dimensional pose of the satellite is determined. Digital simulation results using this algorithm are presented for various satellite poses and lighting conditions.

  3. Online Professors Pose as Students to Encourage Real Learning

    ERIC Educational Resources Information Center

    Parry, Marc

    2009-01-01

    Some professors of online courses are posing as students, infiltrating online course to collect information about students by blending in with them. The deceit has provoked questions about faculty ethics. Two professors admit that their unreal students teeter on an ethical precipice, because the technique could be abused. Others in the…

  4. Astronaut Linda Godwin poses with spacesuit she wore for launch

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Astronaut Linda M. Godwin, STS-59 payload commander, poses with the spacesuit she wore for launch. She will eventually wear the partial pressure suit for the entry phase of the Space Shuttle Endeavour's week and a half mission in Earth orbit.

  5. STS-125 Astronauts Massimino and Johnson pose for Magazine Cover

    NASA Image and Video Library

    2007-12-19

    JSC2007-E-113868 (19 Dec. 2007) --- Astronauts Michael J. Massimino (seated), STS-125 mission specialist; and Gregory H. Johnson, STS-123 pilot, pose for a photo in the motion-base shuttle mission simulator (SMS) in the Jake Garn Simulation and Training Facility at the Johnson Space Center.

  6. STS-125 Astronauts Massimino and Johnson pose for Magazine Cover

    NASA Image and Video Library

    2007-12-19

    JSC2007-E-113866 (19 Dec. 2007) --- Astronauts Michael J. Massimino (seated), STS-125 mission specialist; and Gregory H. Johnson, STS-123 pilot, pose for a photo in the motion-base shuttle mission simulator (SMS) in the Jake Garn Simulation and Training Facility at the Johnson Space Center.

  7. STS-8 crew poses at pad 39A at KSC

    NASA Technical Reports Server (NTRS)

    1983-01-01

    STS-8 crew poses at pad 39A at Kennedy Space Center (KSC) during a session with the news media. From left to right are Astronauts Dale A. Gardner, Guion S. Bluford, and Dr. William E. Thornton, all mission specialists; Daniel C. Brandenstein, pilot; and Richard F. Truly, crew commander.

  8. STS-8 crew poses at pad 39A at KSC

    NASA Technical Reports Server (NTRS)

    1983-01-01

    STS-8 crew poses at pad 39A at Kennedy Space Center (KSC) during a session with the news media. From left to right are Astronauts Dale A. Gardner, Guion S. Bluford, and Dr. William E. Thornton, all mission specialists; Daniel C. Brandenstein, pilot; and RIchard F. Truly, crew commander.

  9. Lessons about Climate Change Pose Many Challenges for Science Teachers

    ERIC Educational Resources Information Center

    Cavanagh, Sean

    2007-01-01

    This article reports on lessons about climate change which pose many challenges for science teachers. The natural world today offers a broad--and dire--catalog of scientific phenomena for teachers wanting to craft classroom lessons on the topic of climate change. As public concern about global warming increases, teachers are carving out a larger…

  10. Body Parts Dependent Joint Regressors for Human Pose Estimation in Still Images.

    PubMed

    Dantone, Matthias; Gall, Juergen; Leistner, Christian; Van Gool, Luc

    2014-11-01

    In this work, we address the problem of estimating 2d human pose from still images. Articulated body pose estimation is challenging due to the large variation in body poses and appearances of the different body parts. Recent methods that rely on the pictorial structure framework have shown to be very successful in solving this task. They model the body part appearances using discriminatively trained, independent part templates and the spatial relations of the body parts using a tree model. Within such a framework, we address the problem of obtaining better part templates which are able to handle a very high variation in appearance. To this end, we introduce parts dependent body joint regressors which are random forests that operate over two layers. While the first layer acts as an independent body part classifier, the second layer takes the estimated class distributions of the first one into account and is thereby able to predict joint locations by modeling the interdependence and co-occurrence of the parts. This helps to overcome typical ambiguities of tree structures, such as self-similarities of legs and arms. In addition, we introduce a novel data set termed FashionPose that contains over 7,000 images with a challenging variation of body part appearances due to a large variation of dressing styles. In the experiments, we demonstrate that the proposed parts dependent joint regressors outperform independent classifiers or regressors. The method also performs better or similar to the state-of-the-art in terms of accuracy, while running with a couple of frames per second.

  11. ROC analysis of ATR from SAR images using a model-based recognizer incorporating pose information

    NASA Astrophysics Data System (ADS)

    Cyganski, David; King, Brian M.; Vaz, Richard F.; Orr, John A.

    1995-06-01

    An automatic taget recognition (ATR) technique developed by the authors features analytically derived object models which are formed from entire image suites, yet are compact and allow a direct target recognition and pose determination procedure. In contrast to the pose-invariant information used to form the models in conventional approaches, view-dependent information is retained in the formation of the compact models for this new approach. All model-based ATR systems are confronted with the problem of image variation as a function of viewing angle. This problem can be addressed by use of an exhaustive library of views, at the expense of a large suite of literal images and a computationally intensive search-based recognition process. Means for overcoming these storage and processing obstacles have traditionally invloved some type of view-independent target representation, often developed from some composite view of the target over the viewing angles of interest. This results in a much more compact target model, and a more direct recognition process. Unfortunately, the gains in storage and computational requirements of these invariant algorithms come at the price of diminished target discrimination capability. The new algorithm incorporates pose as a fundamental parameter which is solved for as part of the recognition process, and does not discard the pose-related information which is relevant to target recognition. In this paper, the newly developed technique is applied to synthetic aperture radar images to develop receiver operating characteristic curves in the presence of both multiplicative noise and clutter. Comparative curves are also developed for a conventional generalized quandratic classifier ATR system.

  12. Face recognition with illumination and pose variations using MINACE filters

    NASA Astrophysics Data System (ADS)

    Casasent, David; Patnaik, Rohit

    2005-10-01

    This paper presents the status of our present CMU face recognition work. We first present a face recognition system that functions in the presence of illumination variations. We then present initial results when pose variations are also considered. A separate minimum noise and correlation energy (MINACE) filter is synthesized for each person. Our concern is face identification and impostor (non-database face) rejection. Most prior face identification did not address impostor rejection. We also present results for face verification with impostor rejection. The MINACE parameter c trades-off distortion-tolerance (recognition) versus discrimination (impostor rejection) performance. We use an automated filter-synthesis algorithm to select c and to synthesize the MINACE filter for each person using a training set of images of that person and a validation set of a few faces of other persons; this synthesis ensures both good recognition and impostor rejection performance. No impostor data is present in the training or validation sets. The peak-tocorrelation energy ratio (PCE) metric is used as the match-score in both the filter-synthesis and test stages and we show that it is better than use of the correlation peak value. We use circular correlations in filter synthesis and in tests, since such filters require one-fourth the storage space and similarly fewer on-line correlation calculations compared to the use of linear correlation filters. All training set images are registered (aligned) using the coordinates of several facial landmarks to remove scale variations and tilt bias. We also discuss the proper handling of pose variations by either pose estimation or by transforming the test input to all reference poses. Our face recognition system is evaluated using images from the CMU Pose, Illumination, and Expression (PIE) database. The same set of MINACE filters and impostor faces are used to evaluate the performance of the face identification and verification systems.

  13. Convolutional Neural Network for Camera Pose Estimation from Object Detections

    NASA Astrophysics Data System (ADS)

    Shalnov, E. V.; Konushin, A. S.

    2017-05-01

    Known scene geometry and camera calibration parameters give important information to video content analysis systems. In this paper, we propose a novel method for camera pose estimation based on people observation in the input video captured by static camera. As opposed to previous techniques, our method can deal with false positive detections and inaccurate localization results. Specifically, the proposed method does not make any assumption about the utilized object detector and takes it as a parameter. Moreover, we do not require a huge labeled dataset of real data and train on the synthetic data only. We apply the proposed technique for camera pose estimation based on head observations. Our experiments show that the algorithm trained on the synthetic dataset generalizes to real data and is robust to false positive detections.

  14. A New Full Pose Measurement Method for Robot Calibration

    PubMed Central

    Nguyen, Hoai-Nhan; Zhou, Jian; Kang, Hee-Jun

    2013-01-01

    Identification of robot kinematic errors during the calibration process often requires accurate full pose measurements (position and orientation) of robot end-effectors in Cartesian space. This paper proposes a new method of full pose measurement of robot end-effectors for calibration. This method is based on an analysis of the features of a set of target points (placed on a rotating end-effector) on a circular trajectory. The accurate measurement is validated by computational simulation results from the Puma robot. Moreover, experimental calibration and validation results for the Hyundai HA-06 robot prove the effectiveness, correctness, and reliability of the proposed method. This method can be applied to robots that have entirely revolute joints or to robots for which only the last joint is revolute. PMID:23863856

  15. Robust feature tracking for endoscopic pose estimation and structure recovery

    NASA Astrophysics Data System (ADS)

    Speidel, S.; Krappe, S.; Röhl, S.; Bodenstedt, S.; Müller-Stich, B.; Dillmann, R.

    2013-03-01

    Minimally invasive surgery is a highly complex medical discipline with several difficulties for the surgeon. To alleviate these difficulties, augmented reality can be used for intraoperative assistance. For visualization, the endoscope pose must be known which can be acquired with a SLAM (Simultaneous Localization and Mapping) approach using the endoscopic images. In this paper we focus on feature tracking for SLAM in minimally invasive surgery. Robust feature tracking and minimization of false correspondences is crucial for localizing the endoscope. As sensory input we use a stereo endoscope and evaluate different feature types in a developed SLAM framework. The accuracy of the endoscope pose estimation is validated with synthetic and ex vivo data. Furthermore we test the approach with in vivo image sequences from da Vinci interventions.

  16. Challenges posed by extracellular vesicles from eukaryotic microbes

    PubMed Central

    Wolf, Julie M.; Casadevall, Arturo

    2014-01-01

    Extracellular vesicles (EV) produced by eukaryotic microbes play an important role during infection. EV release is thought to benefit microbial invasion by delivering a high concentration of virulence factors to distal host cells or to the cytoplasm of a host cell. EV can significantly impact the outcome of host-pathogen interaction in a cargo-dependent manner. Release of EV from eukaryotic microbes poses unique challenges when compared to their bacterial or archaeal counterparts. Firstly, the membrane-bound organelles within eukaryotes facilitate multiple mechanisms of vesicle generation. Secondly, the fungal cell wall poses a unique barrier between the vesicle release site at the plasma membrane and its destined extracellular environment. This review focuses on these eukaryotic-specific aspects of vesicle synthesis and release. PMID:25460799

  17. Wheel pose measurement based on cross structure light

    NASA Astrophysics Data System (ADS)

    Zhao, Qiancheng; Ding, Xun; Wang, Xian; Zhao, Yafeng

    2016-01-01

    It's necessary for automobile to detect and adjust four-wheel alignment parameters regularly, due to the significant effect on improving stability, enhancing security and reducing tire wear of automobiles. In order to measure the parameters that determined by relative position and posture of four wheels to the automobile cab, this paper proposes a method which applies monocular vision of linear structure light to wheel pose measurement. Firstly, space coordinates of feature point cloud are calculated out from the principle of structured light. Then, an algorithm is designed to determine the normal vector of wheel tangent plane and measure the wheel pose. Finally, actual experiments that by evaluation of adjusted wheel angle measurement are carried out to verify the system accuracy. The corresponding studies can be applied in designing and developing 3D four-wheel alignment system that based on structured light.

  18. Sensing Strategies for Disambiguating among Multiple Objects in Known Poses.

    DTIC Science & Technology

    1985-08-01

    ELEMENT. PROIECT. TASK Artificial Inteligence Laboratory AE OKUI UBR 545 Technology Square Cambridge, MA 021.39 11. CONTROLLING OFFICE NAME AND ADDRESS 12...AD-Ali65 912 SENSING STRATEGIES FOR DISAMBIGURTING MONG MULTIPLE 1/1 OBJECTS IN KNOWN POSES(U) MASSACHUSETTS INST OF TECH CAMBRIDGE ARTIFICIAL ...or Dist Special 1 ’ MASSACHUSETTS INSTITUTE OF TECHNOLOGY ARTIFICIAL INTELLIGENCE LABORATORY A. I. Memo 855 August, 1985 Sensing Strategies for

  19. Temporally Scalable Visual SLAM using a Reduced Pose Graph

    DTIC Science & Technology

    2012-05-25

    generated from Kinect data for illustration purposes. II. RELATED WORK The pose graph optimization approach to SLAM was first introduced by Lu and Milios [19...such as the Microsoft Kinect ) and results for both camera types are presented in Section V. Additionally, our approach can incorporate IMU (roll and...camera, a Kinect sensor and a Microstrain IMU among other sensors. The data was collected in a large building over a period of six months. There were

  20. 21. Dr. Harrison E. Stroud poses in front of his ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. Dr. Harrison E. Stroud poses in front of his newly completed building at the northeast corner of Central Avenue and the alley north of Washington Street in about 1900 or 1901. In 1901, the building seen here was enlarged by the construction of an addition of similar design immediately to the north (left). Virtually the entire west elevation of the initial building is depicted in this view. Credit ADLAPR. - Stroud Building, 31-33 North Central Avenue, Phoenix, Maricopa County, AZ

  1. Crew pose for portrait while training at KSC

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The STS 51-L crew poses for a portrait while training at Kennedy Space Center's (KSC) Launch complex 39, Pad B. They are standing in the White Room during a break in countdown training. Left to right are Teacher in Space Payload Specialist Sharon Christa McAuliffe; Payload Specialist Gregory Jarvis; and Astronauts Judith A. Resnik, mission specialist; Francis R. (Dick) Scobee, mission commander; Ronald E. McNair, mission specialist; Mike J. Smith, pilot; and Ellison S. Onizuka, mission specialist.

  2. Crew pose for portrait while training at KSC

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The STS 51-L crew poses for a portrait while training at Kennedy Space Center's (KSC) Launch complex 39, Pad B. They are standing in the White Room during a break in countdown training. Left to right are Teacher in Space Payload Specialist Sharon Christa McAuliffe; Payload Specialist Gregory Jarvis; and Astronauts Judith A. Resnik, mission specialist; Francis R. (Dick) Scobee, mission commander; Ronald E. McNair, mission specialist; Mike J. Smith, pilot; and Ellison S. Onizuka, mission specialist.

  3. A WELL-POSED KELVIN-HELMHOLTZ INSTABILITY TEST AND COMPARISON

    SciTech Connect

    McNally, Colin P.; Lyra, Wladimir; Passy, Jean-Claude E-mail: wlyra@jpl.nasa.gov

    2012-08-01

    Recently, there has been a significant level of discussion of the correct treatment of Kelvin-Helmholtz instability (KHI) in the astrophysical community. This discussion relies largely on how the KHI test is posed and analyzed. We pose a stringent test of the initial growth of the instability. The goal is to provide a rigorous methodology for verifying a code on two-dimensional KHI. We ran the problem in the Pencil Code, Athena, Enzo, NDSPMHD, and Phurbas. A strict comparison, judgment, or ranking, between codes is beyond the scope of this work, though this work provides the mathematical framework needed for such a study. Nonetheless, how the test is posed circumvents the issues raised by tests starting from a sharp contact discontinuity yet it still shows the poor performance of smoothed particle hydrodynamics (SPH). We then comment on the connection between this behavior to the underlying lack of zeroth-order consistency in SPH interpolation. We comment on the tendency of some methods, particularly those with very low numerical diffusion, to produce secondary Kelvin-Helmholtz billows on similar tests. Though the lack of a fixed, physical diffusive scale in the Euler equations lies at the root of the issue, we suggest that in some methods an extra diffusion operator should be used to damp the growth of instabilities arising from grid noise. This statement applies particularly to moving-mesh tessellation codes, but also to fixed-grid Godunov schemes.

  4. Pose-variant facial expression recognition using an embedded image system

    NASA Astrophysics Data System (ADS)

    Song, Kai-Tai; Han, Meng-Ju; Chang, Shuo-Hung

    2008-12-01

    In recent years, one of the most attractive research areas in human-robot interaction is automated facial expression recognition. Through recognizing the facial expression, a pet robot can interact with human in a more natural manner. In this study, we focus on the facial pose-variant problem. A novel method is proposed in this paper to recognize pose-variant facial expressions. After locating the face position in an image frame, the active appearance model (AAM) is applied to track facial features. Fourteen feature points are extracted to represent the variation of facial expressions. The distance between feature points are defined as the feature values. These feature values are sent to a support vector machine (SVM) for facial expression determination. The pose-variant facial expression is classified into happiness, neutral, sadness, surprise or anger. Furthermore, in order to evaluate the performance for practical applications, this study also built a low resolution database (160x120 pixels) using a CMOS image sensor. Experimental results show that the recognition rate is 84% with the self-built database.

  5. Hardware in the Loop Performance Assessment of LIDAR-Based Spacecraft Pose Determination.

    PubMed

    Opromolla, Roberto; Fasano, Giancarmine; Rufino, Giancarlo; Grassi, Michele

    2017-09-24

    In this paper an original, easy to reproduce, semi-analytic calibration approach is developed for hardware-in-the-loop performance assessment of pose determination algorithms processing point cloud data, collected by imaging a non-cooperative target with LIDARs. The laboratory setup includes a scanning LIDAR, a monocular camera, a scaled-replica of a satellite-like target, and a set of calibration tools. The point clouds are processed by uncooperative model-based algorithms to estimate the target relative position and attitude with respect to the LIDAR. Target images, acquired by a monocular camera operated simultaneously with the LIDAR, are processed applying standard solutions to the Perspective-n-Points problem to get high-accuracy pose estimates which can be used as a benchmark to evaluate the accuracy attained by the LIDAR-based techniques. To this aim, a precise knowledge of the extrinsic relative calibration between the camera and the LIDAR is essential, and it is obtained by implementing an original calibration approach which does not need ad-hoc homologous targets (e.g., retro-reflectors) easily recognizable by the two sensors. The pose determination techniques investigated by this work are of interest to space applications involving close-proximity maneuvers between non-cooperative platforms, e.g., on-orbit servicing and active debris removal.

  6. Shape recognition and pose estimation for mobile Augmented Reality.

    PubMed

    Hagbi, Nate; Bergig, Oriel; El-Sana, Jihad; Billinghurst, Mark

    2011-10-01

    Nestor is a real-time recognition and camera pose estimation system for planar shapes. The system allows shapes that carry contextual meanings for humans to be used as Augmented Reality (AR) tracking targets. The user can teach the system new shapes in real time. New shapes can be shown to the system frontally, or they can be automatically rectified according to previously learned shapes. Shapes can be automatically assigned virtual content by classification according to a shape class library. Nestor performs shape recognition by analyzing contour structures and generating projective-invariant signatures from their concavities. The concavities are further used to extract features for pose estimation and tracking. Pose refinement is carried out by minimizing the reprojection error between sample points on each image contour and its library counterpart. Sample points are matched by evolving an active contour in real time. Our experiments show that the system provides stable and accurate registration, and runs at interactive frame rates on a Nokia N95 mobile phone.

  7. Visual measurement system for roadheaders pose detection in mines

    NASA Astrophysics Data System (ADS)

    Du, Yuxin; Tong, Minming; Liu, Ting; Dong, Haibo

    2016-10-01

    To satisfy the demand for automatic roadway drivage in mines, a real-time body pose detection system is proposed for the mine-used boom-type roadheader. Utilizing cross lasers and laser targets as information sources, this system first establishes a mathematical model to describe the machine position in space and realizes the precise localization of reference points on targets via the improved Retinex adaptive image enhancement algorithm and maximum wavelet transform module algorithm. It then sets up the machine body position calculating model and makes use of the space matrix transformation method to obtain the yaw, pitch, roll angles, and horizontal and vertical deviations of the roadheader, finally fulfilling the automatic machine pose detection in real time. Based on the preceding theoretical analysis, an experimental platform is built up in laboratory conditions for the purpose of simulating pose changes of the machine inside the tunnel and automatically detecting its position. The experimental results show that the measurement accuracy of angles is within 0.16 deg and the detection precision of displacements is higher than 10 mm, which can satisfy requirements of automatic, precise, and real-time positioning for the roadheader during the process of tunnel construction.

  8. Teaching human poses interactively to a social robot.

    PubMed

    Gonzalez-Pacheco, Victor; Malfaz, Maria; Fernandez, Fernando; Salichs, Miguel A

    2013-09-17

    The main activity of social robots is to interact with people. In order to do that, the robot must be able to understand what the user is saying or doing. Typically, this capability consists of pre-programmed behaviors or is acquired through controlled learning processes, which are executed before the social interaction begins. This paper presents a software architecture that enables a robot to learn poses in a similar way as people do. That is, hearing its teacher's explanations and acquiring new knowledge in real time. The architecture leans on two main components: an RGB-D (Red-, Green-, Blue- Depth) -based visual system, which gathers the user examples, and an Automatic Speech Recognition (ASR) system, which processes the speech describing those examples. The robot is able to naturally learn the poses the teacher is showing to it by maintaining a natural interaction with the teacher. We evaluate our system with 24 users who teach the robot a predetermined set of poses. The experimental results show that, with a few training examples, the system reaches high accuracy and robustness. This method shows how to combine data from the visual and auditory systems for the acquisition of new knowledge in a natural manner. Such a natural way of training enables robots to learn from users, even if they are not experts in robotics.

  9. Intrinsic Feature Pose Measurement for Awake Animal SPECT Imaging

    SciTech Connect

    Goddard Jr, James Samuel; Baba, Justin S; Lee, Seung Joon; Weisenberger, A G; Stolin, A; McKisson, J; Smith, M F

    2009-01-01

    New developments have been made in optical motion tracking for awake animal imaging that measures 3D position and orientation (pose) for a single photon emission computed tomography (SPECT) imaging system. Ongoing SPECT imaging research has been directed towards head motion measurement for brain studies in awake, unrestrained mice. In contrast to previous results using external markers, this work extracts and tracks intrinsic features from multiple camera images and computes relative pose from the tracked features over time. Motion tracking thus far has been limited to measuring extrinsic features such as retro-reflective markers applied to the mouse s head. While this approach has been proven to be accurate, the additional animal handling required to attach the markers is undesirable. A significant improvement in the procedure is achieved by measuring the pose of the head without extrinsic markers using only the external surface appearance. This approach is currently being developed with initial results presented here. The intrinsic features measurement extracts discrete, sparse natural features from 2D images such as eyes, nose, mouth and other visible structures. Stereo correspondence between features for a camera pair is determined for calculation of 3D positions. These features are also tracked over time to provide continuity for surface model fitting. Experimental results from live images are presented.

  10. Teaching Human Poses Interactively to a Social Robot

    PubMed Central

    Gonzalez-Pacheco, Victor; Malfaz, Maria; Fernandez, Fernando; Salichs, Miguel A.

    2013-01-01

    The main activity of social robots is to interact with people. In order to do that, the robot must be able to understand what the user is saying or doing. Typically, this capability consists of pre-programmed behaviors or is acquired through controlled learning processes, which are executed before the social interaction begins. This paper presents a software architecture that enables a robot to learn poses in a similar way as people do. That is, hearing its teacher's explanations and acquiring new knowledge in real time. The architecture leans on two main components: an RGB-D (Red-, Green-, Blue- Depth) -based visual system, which gathers the user examples, and an Automatic Speech Recognition (ASR) system, which processes the speech describing those examples. The robot is able to naturally learn the poses the teacher is showing to it by maintaining a natural interaction with the teacher. We evaluate our system with 24 users who teach the robot a predetermined set of poses. The experimental results show that, with a few training examples, the system reaches high accuracy and robustness. This method shows how to combine data from the visual and auditory systems for the acquisition of new knowledge in a natural manner. Such a natural way of training enables robots to learn from users, even if they are not experts in robotics. PMID:24048336

  11. STS-31 MS Sullivan poses next to stowed EMU in OV-103's airlock

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-31 Mission Specialist (MS) Kathryn D. Sullivan poses for a picture before beginning extravehicular mobility unit (EMU) donning procedures in the airlock of Discovery, Orbiter Vehicle (OV) 103. Sullivan will remove the lower torso restraint and don EMU which is supported on an airlock adapter plate (AAP). When suited, Sullivan will be ready for contingency extravehicular activity (EVA) in the event that problems arise with the Hubble Space Telescope (HST) deployment. Displayed on the front of the EMU are the STS-31 mission insignia and the JSC Weightless Environment Training Facility (WETF) insignia.

  12. Monocular Vision- and IMU-Based System for Prosthesis Pose Estimation During Total Hip Replacement Surgery.

    PubMed

    Su, Shaojie; Zhou, Yixin; Wang, Zhihua; Chen, Hong

    2017-03-30

    The average age of population increases worldwide, so does the number of total hip replacement surgeries. Total hip replacement, however, often involves a risk of dislocation and prosthetic impingement. To minimize the risk after surgery, we propose an instrumented hip prosthesis that estimates the relative pose between prostheses intraoperatively and ensures the placement of prostheses within a safe zone. We create a model of the hip prosthesis as a ball and socket joint, which has four degrees of freedom (DOFs), including 3-DOF rotation and 1-DOF translation. We mount a camera and an inertial measurement unit (IMU) inside the hollow ball, or "femoral head prosthesis," while printing customized patterns on the internal surface of the socket, or "acetabular cup." Since the sensors were rigidly fixed to the femoral head prosthesis, measuring its motions poses a sensor ego-motion estimation problem. By matching feature points in images of the reference patterns, we propose a monocular vision based method with a relative error of less than 7% in the 3-DOF rotation and 8% in the 1-DOF translation. Further, to reduce system power consumption, we apply the IMU with its data fused by an extended Kalman filter to replace the camera in the 3-DOF rotation estimation, which yields a less than 4.8% relative error and a 21.6% decrease in power consumption. Experimental results show that the best approach to prosthesis pose estimation is a combination of monocular vision-based translation estimation and IMU-based rotation estimation, and we have verified the feasibility and validity of this system in prosthesis pose estimation.

  13. Real-time upper-body human pose estimation from depth data using Kalman filter for simulator

    NASA Astrophysics Data System (ADS)

    Lee, D.; Chi, S.; Park, C.; Yoon, H.; Kim, J.; Park, C. H.

    2014-08-01

    Recently, many studies show that an indoor horse riding exercise has a positive effect on promoting health and diet. However, if a rider has an incorrect posture, it will be the cause of back pain. In spite of this problem, there is only few research on analyzing rider's posture. Therefore, the purpose of this study is to estimate a rider pose from a depth image using the Asus's Xtion sensor in real time. In the experiments, we show the performance of our pose estimation algorithm in order to comparing the results between our joint estimation algorithm and ground truth data.

  14. The Problem with Women? Challenges Posed by Gender for Career Guidance Practice

    ERIC Educational Resources Information Center

    Bimrose, Jenny; Watson, Mark; McMahon, Mary; Haasler, Simone; Tomassini, Massimo; Suzanne, Pamela A.

    2014-01-01

    Institutionalised discrimination continues to perpetuate deep rooted social divisions, with gender inequality persisting as a pervasive feature of labour markets across the world. Despite the depth and breadth of gender inequality, there is limited acknowledgement in career theory that the career support needs of women are distinctive. A…

  15. Field Dependence/Independence Cognitive Style and Problem Posing: An Investigation with Sixth Grade Students

    ERIC Educational Resources Information Center

    Nicolaou, Aristoklis Andreas; Xistouri, Xenia

    2011-01-01

    Field dependence/independence cognitive style was found to relate to general academic achievement and specific areas of mathematics; in the majority of studies, field-independent students were found to be superior to field-dependent students. The present study investigated the relationship between field dependence/independence cognitive style and…

  16. The Posing of Division Problems by Preservice Elementary School Teachers: Conceptual Knowledge and Contextual Connections.

    ERIC Educational Resources Information Center

    Silver, Edward A.; Burkett, Mary Lee

    Previous research has suggested that many elementary school teachers have a firmer understanding of addition and subtraction concepts than they have of more complex topics in elementary mathematics, such as division. In this study, (n=24) prospective elementary teachers' understanding of aspects of division involving remainders was explored by…

  17. Wartime Interoperability Problems Posed by Differences in South Korean and United States Army Tactics.

    DTIC Science & Technology

    1980-06-06

    Tactics. South Korea. 20. AIETIRACT (Cb.bue m ,everme aft f neem and tdenlf by block numbet) See reverse. DO , FA 1473 IEDITOM OF f MOV 65 IS o8SOLET... production ( manufacturing) guerilla units. 12 14 Witn a population less than half that of South Korea’s, and exports amounting to only 7% those of the...personal possessions. These statements are in no way intended to degrade the American officer, but are intended to convey something of the mental attitude of

  18. Overview of potential mutagenic problems posed by some pesticides and their trace impurities.

    PubMed Central

    Fishbein, L

    1978-01-01

    This review principally addresses a number of aspects of usage of pesticides as well as populations at potential risk and attempts to highlight categories of pesticides whose structures or those of their metabolites and/or trace impurities, degradation and transformation products suggest an a priori mutagenic and/or carcinogenic risk. The pesticides considered include: DDT, hexachlorobenzene (HCB), 2,4,5-T, pentachlorophenol, and various herbicidal precursors (e.g., carbamates, triazines) of nitrosamines and nitroso derivatives. Structural features of a number of halo-unsaturated pesticides (e.g., dichloropropenes) were also reviewed from a viewpoint of contrasting their potential mutagenicity with that of vinyl chloride and vinylidene chloride. Additionally the mutagenicity of the organophosphorus pesticide Trichlorophon is contrasted with that of its degradation products. PMID:367764

  19. Challenging the Wikipedia Mentality: Encouraging Original Inquiry through Freire's Problem-Posing Method

    ERIC Educational Resources Information Center

    Deys, Kellie L.; Deys, James L.

    2016-01-01

    For most millennials, information has always been a couple of quick taps away. Sites have seemingly always existed to provide them with "the answer." Instructors must recognize that not only are they teaching material from their disciplines, but also they are trying to teach the skill and value of critical inquiry. Adopting a Freirean…

  20. [Diagnostic problems posed by hypotrophic facio-scapulo-humeral syndromes (author's transl)].

    PubMed

    Grassi, E; Marbini, A; Marchini, C; Parma, M; Zampollo, A

    1976-01-01

    The Authors, on the ground of the literature and of their own observations, stress the diagnostic non specificity of hypotrophic facio-scapulo-humeral syndromes: these sindromes, contrary to the current opinion, aren't always of primitive myodistrophic nature but may also be "neurogenic", inflammatory, collagenopathis, etc. In this connection they present an illustrative case of facio-scapulo-humeral syndrome which had clinical features typically "myogenic" but turned out to be "neurogenic" after electromyographic and histochemical investigation.

  1. Youthfulness, inexperience, and sleep loss: the problems young drivers face and those they pose for us

    PubMed Central

    Groeger, J A

    2006-01-01

    Young inexperienced drivers are more likely to be involved in road traffic crashes than drivers who are older and more experienced. This paper argues that neither age nor inexperience are, in and of themselves, sufficient explanations of the association between age, experience, and casualty rates. The aim here is to consider what it is about inexperienced young drivers in particular that may increase crash risk. Evidence is reviewed showing differential sleep loss among different teenage groups, which may relate to recently presented evidence that young teenagers are more crash involved than drivers in their early twenties. Potential acute and chronic effects of sleep loss among teenagers and young adults are described. PMID:16788107

  2. How cyanobacteria pose new problems to old methods: challenges in microarray time series analysis

    PubMed Central

    2013-01-01

    Background The transcriptomes of several cyanobacterial strains have been shown to exhibit diurnal oscillation patterns, reflecting the diurnal phototrophic lifestyle of the organisms. The analysis of such genome-wide transcriptional oscillations is often facilitated by the use of clustering algorithms in conjunction with a number of pre-processing steps. Biological interpretation is usually focussed on the time and phase of expression of the resulting groups of genes. However, the use of microarray technology in such studies requires the normalization of pre-processing data, with unclear impact on the qualitative and quantitative features of the derived information on the number of oscillating transcripts and their respective phases. Results A microarray based evaluation of diurnal expression in the cyanobacterium Synechocystis sp. PCC 6803 is presented. As expected, the temporal expression patterns reveal strong oscillations in transcript abundance. We compare the Fourier transformation-based expression phase before and after the application of quantile normalization, median polishing, cyclical LOESS, and least oscillating set (LOS) normalization. Whereas LOS normalization mostly preserves the phases of the raw data, the remaining methods introduce systematic biases. In particular, quantile-normalization is found to introduce a phase-shift of 180°, effectively changing night-expressed genes into day-expressed ones. Comparison of a large number of clustering results of differently normalized data shows that the normalization method determines the result. Subsequent steps, such as the choice of data transformation, similarity measure, and clustering algorithm, only play minor roles. We find that the standardization and the DTF transformation are favorable for the clustering of time series in contrast to the 12 m transformation. We use the cluster-wise functional enrichment of a clustering derived by LOS normalization, clustering using flowClust, and DFT transformation to derive the diurnal biological program of Synechocystis sp.. Conclusion Application of quantile normalization, median polishing, and also cyclic LOESS normalization of the presented cyanobacterial dataset lead to increased numbers of oscillating genes and the systematic shift of the expression phase. The LOS normalization minimizes the observed detrimental effects. As previous analyses employed a variety of different normalization methods, a direct comparison of results must be treated with caution. PMID:23601192

  3. The Problem with Women? Challenges Posed by Gender for Career Guidance Practice

    ERIC Educational Resources Information Center

    Bimrose, Jenny; Watson, Mark; McMahon, Mary; Haasler, Simone; Tomassini, Massimo; Suzanne, Pamela A.

    2014-01-01

    Institutionalised discrimination continues to perpetuate deep rooted social divisions, with gender inequality persisting as a pervasive feature of labour markets across the world. Despite the depth and breadth of gender inequality, there is limited acknowledgement in career theory that the career support needs of women are distinctive. A…

  4. How members of the human gut microbiota overcome the sulfation problem posed by glycosaminoglycans

    PubMed Central

    Cartmell, Alan; Lowe, Elisabeth C.; Baslé, Arnaud; Firbank, Susan J.; Ndeh, Didier A.; Murray, Heath; Terrapon, Nicolas; Lombard, Vincent; Henrissat, Bernard; Turnbull, Jeremy E.; Czjzek, Mirjam; Gilbert, Harry J.; Bolam, David N.

    2017-01-01

    The human microbiota, which plays an important role in health and disease, uses complex carbohydrates as a major source of nutrients. Utilization hierarchy indicates that the host glycosaminoglycans heparin (Hep) and heparan sulfate (HS) are high-priority carbohydrates for Bacteroides thetaiotaomicron, a prominent member of the human microbiota. The sulfation patterns of these glycosaminoglycans are highly variable, which presents a significant enzymatic challenge to the polysaccharide lyases and sulfatases that mediate degradation. It is possible that the bacterium recruits lyases with highly plastic specificities and expresses a repertoire of enzymes that target substructures of the glycosaminoglycans with variable sulfation or that the glycans are desulfated before cleavage by the lyases. To distinguish between these mechanisms, the components of the B. thetaiotaomicron Hep/HS degrading apparatus were analyzed. The data showed that the bacterium expressed a single-surface endo-acting lyase that cleaved HS, reflecting its higher molecular weight compared with Hep. Both Hep and HS oligosaccharides imported into the periplasm were degraded by a repertoire of lyases, with each enzyme displaying specificity for substructures within these glycosaminoglycans that display a different degree of sulfation. Furthermore, the crystal structures of a key surface glycan binding protein, which is able to bind both Hep and HS, and periplasmic sulfatases reveal the major specificity determinants for these proteins. The locus described here is highly conserved within the human gut Bacteroides, indicating that the model developed is of generic relevance to this important microbial community. PMID:28630303

  5. [Problems posed by the interpretation of peroxidase labelling of various neurons in Cyprinidae].

    PubMed

    Peyrichoux, J; Weidner, C; Repérant, J

    1976-11-29

    The origin of a centrifugal visual pathway in Cyprinids could not be demonstrated with the technique involving the labelling of cell bodies by retrograde transport of Horseradish Peroxidase. The hypothalamic labelling following intraocular injection of HRP is localized in neurosecretory structures which take up the enzyme that has passed into the circulatory system. Identical results were obtained following direct intracardiac injection. Thus extreme caution must be taken in attempting to interpret HRP results.

  6. Field Dependence/Independence Cognitive Style and Problem Posing: An Investigation with Sixth Grade Students

    ERIC Educational Resources Information Center

    Nicolaou, Aristoklis Andreas; Xistouri, Xenia

    2011-01-01

    Field dependence/independence cognitive style was found to relate to general academic achievement and specific areas of mathematics; in the majority of studies, field-independent students were found to be superior to field-dependent students. The present study investigated the relationship between field dependence/independence cognitive style and…

  7. Posing Problems Without an Alliance: China-Iran Relations after the Nuclear Deal

    DTIC Science & Technology

    2016-03-25

    Iran’s nuclear program has led to bullish predictions about the future of Sino-Iranian rela- tions. Under the deal, Iran is expected to limit its uranium...enrichment and make other changes to its nuclear program in exchange for the removal of internation- al sanctions.1 China is expected to be a prime...Alliance: China-Iran Relations after the Nuclear Deal by Joel Wuthnow STRATEGIC FORUM National Defense University About the Author Dr. Joel Wuthnow is a

  8. Cognitive Styles in Posing Geometry Problems: Implications for Assessment of Mathematical Creativity

    ERIC Educational Resources Information Center

    Singer, Florence Mihaela; Voica, Cristian; Pelczer, Ildikó

    2017-01-01

    While a wide range of approaches and tools have been used to study children's creativity in school contexts, less emphasis has been placed on revealing students' creativity at university level. The present paper is focused on defining a tool that provides information about mathematical creativity of prospective mathematics teachers in…

  9. Challenging the Wikipedia Mentality: Encouraging Original Inquiry through Freire's Problem-Posing Method

    ERIC Educational Resources Information Center

    Deys, Kellie L.; Deys, James L.

    2016-01-01

    For most millennials, information has always been a couple of quick taps away. Sites have seemingly always existed to provide them with "the answer." Instructors must recognize that not only are they teaching material from their disciplines, but also they are trying to teach the skill and value of critical inquiry. Adopting a Freirean…

  10. The vulnerability of rules in complex work environments: dynamism and uncertainty pose problems for cognition.

    PubMed

    Clewley, Richard; Stupple, Edward J N

    2015-01-01

    Many complex work environments rely heavily on cognitive operators using rules. Operators sometimes fail to implement rules, with catastrophic human, social and economic costs. Rule-based error is widely reported, yet the mechanisms of rule vulnerability have received less attention. This paper examines rule vulnerability in the complex setting of airline transport operations. We examined 'the stable approach criteria rule', which acts as a system defence during the approach to land. The study experimentally tested whether system state complexity influenced rule failure. The results showed increased uncertainty and dynamism led to increased likelihood of rule failure. There was also an interaction effect, indicating complexity from different sources can combine to further constrain rule-based response. We discuss the results in relation to recent aircraft accidents and suggest that 'rule-based error' could be progressed to embrace rule vulnerability, fragility and failure. This better reflects the influence that system behaviour and cognitive variety have on rule-based response. Practitioner Summary: In this study, we examined mechanisms of rule vulnerability in the complex setting of airline transport operations. The results suggest work scenarios featuring high uncertainty and dynamism constrain rule-based response, leading to rules becoming vulnerable, fragile or failing completely. This has significant implications for rule-intensive, safety critical work environments.

  11. Macrobend optical sensing for pose measurement in soft robot arms

    NASA Astrophysics Data System (ADS)

    Sareh, Sina; Noh, Yohan; Li, Min; Ranzani, Tommaso; Liu, Hongbin; Althoefer, Kaspar

    2015-12-01

    This paper introduces a pose-sensing system for soft robot arms integrating a set of macrobend stretch sensors. The macrobend sensory design in this study consists of optical fibres and is based on the notion that bending an optical fibre modulates the intensity of the light transmitted through the fibre. This sensing method is capable of measuring bending, elongation and compression in soft continuum robots and is also applicable to wearable sensing technologies, e.g. pose sensing in the wrist joint of a human hand. In our arrangement, applied to a cylindrical soft robot arm, the optical fibres for macrobend sensing originate from the base, extend to the tip of the arm, and then loop back to the base. The connectors that link the fibres to the necessary opto-electronics are all placed at the base of the arm, resulting in a simplified overall design. The ability of this custom macrobend stretch sensor to flexibly adapt its configuration allows preserving the inherent softness and compliance of the robot which it is installed on. The macrobend sensing system is immune to electrical noise and magnetic fields, is safe (because no electricity is needed at the sensing site), and is suitable for modular implementation in multi-link soft continuum robotic arms. The measurable light outputs of the proposed stretch sensor vary due to bend-induced light attenuation (macrobend loss), which is a function of the fibre bend radius as well as the number of repeated turns. The experimental study conducted as part of this research revealed that the chosen bend radius has a far greater impact on the measured light intensity values than the number of turns (if greater than five). Taking into account that the bend radius is the only significantly influencing design parameter, the macrobend stretch sensors were developed to create a practical solution to the pose sensing in soft continuum robot arms. Henceforward, the proposed sensing design was benchmarked against an electromagnetic

  12. Dynamics of solitons to the ill-posed Boussinesq equation

    NASA Astrophysics Data System (ADS)

    Tchier, Fairouz; Aliyu, Aliyu Isa; Yusuf, Abdullahi; Inc, Mustafa

    2017-03-01

    In this paper, we analyze the dynamic behavior of the ill-posed Boussinesq equation (IPBE) that arises in nonlinear lattices and also in shallow water waves. Some solitary wave solutions are obtained by using the solitary wave ansatz method and the Bernoulli sub-Ode. By applying the technique of nonlinear self-adjoint, a quasi self-adjoint substitution for the IPBE is constructed. The classical symmetries of the equation are constructed. Then, we used along with the obtained nonlinear self-adjoint substitution to construct a set of new conservation laws (Cls).

  13. UAV to UAV Target Detection and Pose Estimation

    DTIC Science & Technology

    2012-06-01

    ADS-B). In Federal Aviation Administration (FAA), 2007. [11] D. Shim, H. Chung, H.J. Kim and S. Sastry . Autonomous Exploration in Unknown Urban...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS UAV TO UAV TARGET DETECTION AND POSE ESTIMATION by Riadh Hajri June 2012 Thesis Advisor...19b. TELEPHONE NUMBER (include area code) NSN 7540-01-280-5500 Standard Form 298 (Rev. 8–98) Prescribed by ANSI Std. Z39.18 6–6– 2012 Master’s Thesis

  14. Rocky Mountain federal lands pose widespread access issues

    SciTech Connect

    Crow, P.

    1997-02-03

    The paper discusses oil and gas leasing constraints posed by federal regulations. Clinton`s executive order setting aside 1.7 million acres in Utah, a re-inventory of all Bureau of Land Management (BLM) wilderness areas in Utah, US Forest Service draft environmental impact statement regarding oil and gas leasing in the Lewis and Clark National Forest in Montana, Colorado BLM interim decision not to issue leases in areas proposed for wilderness by environmental groups, air quality issues in Wyoming, and attempts to block the completion of the Express Pipeline are some of the issues discussed.

  15. Expedition 22 Crewmembers pose for photo during Expedition 22

    NASA Image and Video Library

    2010-03-13

    ISS022-E-091547 (13 March 2010) --- Crew members on the International Space Station pose for a photo in the station?s Kibo laboratory. Pictured on the front row are NASA astronaut Jeffrey Williams (right), Expedition 22 commander; and Russian cosmonaut Maxim Suraev, Expedition 22 flight engineer. Pictured on the back row are Russian cosmonaut Oleg Kotov (center), Expedition 22 flight engineer and Expedition 23 commander; NASA astronaut T.J. Creamer (left) and Japan Aerospace Exploration Agency (JAXA) astronaut Soichi Noguchi, both Expedition 22/23 flight engineers. Williams and Suraev are scheduled to return to Earth on March 18, 2010, completing almost a half-year aboard the station.

  16. A non-expert-user interface for posing signing avatars.

    PubMed

    Adamo-Villani, Nicoletta; Popescu, Voicu; Lestina, Jason

    2013-05-01

    We describe a graphical user interface designed to allow non-expert users to pose 3D characters to create American Sign Language (ASL) computer animation. The interface is an important component of a software system that allows educators of the Deaf to add sign language translation, in the form of 3D character animations, to digital learning materials, thus making them accessible to deaf learners. A study indicates that users with no computer animation expertize can create animated ASL signs quickly and accurately.

  17. Exterior view of submarine with survey crew posed in front. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Exterior view of submarine with survey crew posed in front. From left to right: Todd Croteau - U.S. National Park Service, Joshua Price - U.S. Navy, Bert Ho - National Oceanic and Atmospheric Administration, Michael McCarthy - Western Australia Maritime Museum, Larry Murphy - U.S. National Park Service, Don Johnson- University of Nebraska Engineering School, James Delgado- Institute for Nautical Archeology, Jacinto Ahmendra - Government of Panama. - Sub Marine Explorer, Located along the beach of Isla San Telmo, Pearl Islands, Isla San Telmo, Former Panama Canal Zone, CZ

  18. Onboard camera pose estimation in augmented reality space for direct visual navigation

    NASA Astrophysics Data System (ADS)

    Hu, Zhencheng; Uchimura, Keiichi

    2003-05-01

    This paper presents a dynamical solution of the registration problem for on-road navigation applications via 3D-2D parameterized model matching algorithm. Traditional camera"s three dimensional (3D) position and pose estimation algorithms always employ the fixed and known-structure models as well as the depth information to obtain the 3D-2D correlations, which is however unavailable for on-road navigation applications since there are no fixed models in the general road scene. With the constraints of road structure and on-road navigation features, this paper presents a 2D digital road map based road shape modeling algorithm. Dynamically generated multi-lane road shape models are used to match real road scene to estimate camera 3D position and pose data. Our algorithms successfully simplified the 3D-2D correlation problem to the 2D-2D road model matching on the projective image. The algorithms proposed in this paper are validated with the experimental results from real road test under different conditions and types of road.

  19. [Ethical and health issues posed by the recent Ebola epidemic: What should we learn?].

    PubMed

    Pablo Beca, Juan; Salas, Sofía P

    2016-03-01

    The recent Ebola epidemic that affected several countries in Africa, with very high mortality and a pandemic threat, posed problems of justice, public health, prevention, treatment and research, each of which has relevant ethical issues. Despite severe initial difficulties, an effective international response was achieved, whose outcome has left significant teachings to be considered in order to deal with future epidemics or pandemics. In this article, the authors analyze the main problems faced during the Ebola epidemic, including the unequal distribution of health resources between countries, the need for international collaboration, the requirement for a review of the ethical standards of clinical trials in emergencies, and the necessity of an organized global system of prevention and timely response to these outbreaks. Authors conclude that at the present time health is a global issue without borders, that insufficient healthcare resources in some countries poses risks and affects all countries and that the confrontation of the threats of epidemics requires a solution based in universal solidarity. At the same time, a moral duty to investigate should be acknowledged, seeking a balance between sense of urgency, scientific rigor and involvement of local communities.

  20. A discrete model for an ill-posed nonlinear parabolic PDE

    NASA Astrophysics Data System (ADS)

    Witelski, Thomas P.; Schaeffer, David G.; Shearer, Michael

    2001-12-01

    We study a finite-difference discretization of an ill-posed nonlinear parabolic partial differential equation. The PDE is the one-dimensional version of a simplified two-dimensional model for the formation of shear bands via anti-plane shear of a granular medium. For the discretized initial value problem, we derive analytically, and observed numerically, a two-stage evolution leading to a steady-state: (i) an initial growth of grid-scale instabilities, and (ii) coarsening dynamics. Elaborating the second phase, at any fixed time the solution has a piecewise linear profile with a finite number of shear bands. In this coarsening phase, one shear band after another collapses until a steady-state with just one jump discontinuity is achieved. The amplitude of this steady-state shear band is derived analytically, but due to the ill-posedness of the underlying problem, its position exhibits sensitive dependence. Analyzing data from the simulations, we observe that the number of shear bands at time t decays like t-1/3. From this scaling law, we show that the time-scale of the coarsening phase in the evolution of this model for granular media critically depends on the discreteness of the model. Our analysis also has implications to related ill-posed nonlinear PDEs for the one-dimensional Perona-Malik equation in image processing and to models for clustering instabilities in granular materials.

  1. A monocular vision system based on cooperative targets detection for aircraft pose measurement

    NASA Astrophysics Data System (ADS)

    Wang, Zhenyu; Wang, Yanyun; Cheng, Wei; Chen, Tao; Zhou, Hui

    2017-08-01

    In this paper, a monocular vision measurement system based on cooperative targets detection is proposed, which can capture the three-dimensional information of objects by recognizing the checkerboard target and calculating of the feature points. The aircraft pose measurement is an important problem for aircraft’s monitoring and control. Monocular vision system has a good performance in the range of meter. This paper proposes an algorithm based on coplanar rectangular feature to determine the unique solution of distance and angle. A continuous frame detection method is presented to solve the problem of corners’ transition caused by symmetry of the targets. Besides, a displacement table test system based on three-dimensional precision and measurement system human-computer interaction software has been built. Experiment result shows that it has a precision of 2mm in the range of 300mm to 1000mm, which can meet the requirement of the position measurement in the aircraft cabin.

  2. Questions posed to hospital chaplains by palliative care patients.

    PubMed

    Strang, Susan; Strang, Peter

    2002-12-01

    Questions of vital importance are actualized when facing one's own death. Studies on patient need for a hospital chaplaincy as an integral part of hospital care are lacking. To categorize the three most important questions patients pose to hospital chaplains at the end of life and to assess the degree to which hospital staff should be able to handle them. A Swedish national survey using an open-ended questionnaire and content analysis. One hundred seventy-two Swedish hospital chaplains (national coverage, 74% response rate). Categories developed from open-ended questions. Categories of questions posed to hospital chaplains. Five main categories were identified: meaning (34%); death and dying (21%); pain and illness (13%); relationships (15%); and religious issues (8%). Questions of a general existential nature concerned with meaning-related issues and with death and dying were frequently the primary issue. Many questions dealt with pain, fear of suffocation, and illness in general (i.e., questions that the palliative team should be able to handle). Only 8% of the issues were explicitly religious and these were often third-hand choices. The role of the hospital chaplaincy has changed. Today it entails specialized competence and is needed in existential discussions with different patients in crisis, regardless of their personal faith or lack of faith. Nonetheless, physicians and other staff members should be able to handle many of the questions that are of a more general/medical character.

  3. Toward active pose estimation of a grasped object

    NASA Astrophysics Data System (ADS)

    Abbott, A. Lynn

    1993-08-01

    This paper concerns the use of visual feedback to verify whether an object has been properly grasped by a manipulator. The work is motivated by the fact that many general-purpose manipulators are equipped with very simple grippers which may not be well suited to grasping common objects. Furthermore, many robotic systems do not verify that a grasp operation has been successfully executed. This paper describes a system under development at Virginia Tech which utilizes visual feedback to guide relative camera-object movements for the purpose of estimating the pose of the object. The goal is to assist in computing object pose relative to a coordinate system embedded in the gripper. Object shape is assumed to be known in advance. Two methods are discussed, both of which utilize visually guided movements to search for a minimum in an objective function. The first method is to align the gripper with the image plane, facilitating the computation of object orientation about the normal to the image plane. The second involves moving the object to align its image with a desired view of the object. Extensive calibration of the camera or manipulator is not required. The methods discussed here are still at the conceptual stage, but illustrate the potential of the active approach.

  4. High Methionine Diet Poses Cardiac Threat: A Molecular Insight.

    PubMed

    Chaturvedi, Pankaj; Kamat, Pradip K; Kalani, Anuradha; Familtseva, Anastasia; Tyagi, Suresh C

    2016-07-01

    High methionine diet (HMD) for example red meat which includes lamb, beef, pork can pose cardiac threat and vascular dysfunction but the mechanisms are unclear. We hypothesize that a diet rich in methionine can malfunction the cardiovascular system in three ways: (1) by augmenting oxidative stress; (2) by inflammatory manifestations; and (3) by matrix/vascular remodeling. To test this hypothesis we used four groups of mice: (1) WT; (2) WT + methionine; (3) CBS(+/-) ; (4) CBS(+/-) +methionine. We observed high oxidative stress in mice fed with methionine which was even higher in CBS(+/-) and CBS(+/-) +methionine. Higher oxidative stress was indicated by high levels of SOD-1 in methionine fed mouse hearts whereas IL-1β, IL-6, TNFα, and TLR4 showed high inflammatory manifestations. The upregulated levels of eNOS/iNOS and upregulated levels of MMP2/MMP9 along with high collagen deposition indicated vascular and matrix remodeling in methionine fed mouse. We evaluated the cardiac function which was dysregulated in the mice fed with HMD. These mice had decreased ejection fraction and left ventricular dysfunction which subsequently leads to adverse cardiac remodeling. In conclusion, our study clearly shows that HMD poses a cardiac threat by increasing oxidative stress, inflammatory manifestations, matrix/vascular remodeling, and decreased cardiac function.

  5. Exhaustive linearization for robust camera pose and focal length estimation.

    PubMed

    Penate-Sanchez, Adrian; Andrade-Cetto, Juan; Moreno-Noguer, Francesc

    2013-10-01

    We propose a novel approach for the estimation of the pose and focal length of a camera from a set of 3D-to-2D point correspondences. Our method compares favorably to competing approaches in that it is both more accurate than existing closed form solutions, as well as faster and also more accurate than iterative ones. Our approach is inspired on the EPnP algorithm, a recent O(n) solution for the calibrated case. Yet we show that considering the focal length as an additional unknown renders the linearization and relinearization techniques of the original approach no longer valid, especially with large amounts of noise. We present new methodologies to circumvent this limitation termed exhaustive linearization and exhaustive relinearization which perform a systematic exploration of the solution space in closed form. The method is evaluated on both real and synthetic data, and our results show that besides producing precise focal length estimation, the retrieved camera pose is almost as accurate as the one computed using the EPnP, which assumes a calibrated camera.

  6. 3D face recognition under expressions, occlusions, and pose variations.

    PubMed

    Drira, Hassen; Ben Amor, Boulbaba; Srivastava, Anuj; Daoudi, Mohamed; Slama, Rim

    2013-09-01

    We propose a novel geometric framework for analyzing 3D faces, with the specific goals of comparing, matching, and averaging their shapes. Here we represent facial surfaces by radial curves emanating from the nose tips and use elastic shape analysis of these curves to develop a Riemannian framework for analyzing shapes of full facial surfaces. This representation, along with the elastic Riemannian metric, seems natural for measuring facial deformations and is robust to challenges such as large facial expressions (especially those with open mouths), large pose variations, missing parts, and partial occlusions due to glasses, hair, and so on. This framework is shown to be promising from both--empirical and theoretical--perspectives. In terms of the empirical evaluation, our results match or improve upon the state-of-the-art methods on three prominent databases: FRGCv2, GavabDB, and Bosphorus, each posing a different type of challenge. From a theoretical perspective, this framework allows for formal statistical inferences, such as the estimation of missing facial parts using PCA on tangent spaces and computing average shapes.

  7. Pose Estimation and Mapping Using Catadioptric Cameras with Spherical Mirrors

    NASA Astrophysics Data System (ADS)

    Ilizirov, Grigory; Filin, Sagi

    2016-06-01

    Catadioptric cameras have the advantage of broadening the field of view and revealing otherwise occluded object parts. However, they differ geometrically from standard central perspective cameras because of light reflection from the mirror surface which alters the collinearity relation and introduces severe non-linear distortions of the imaged scene. Accommodating for these features, we present in this paper a novel modeling for pose estimation and reconstruction while imaging through spherical mirrors. We derive a closed-form equivalent to the collinearity principle via which we estimate the system's parameters. Our model yields a resection-like solution which can be developed into a linear one. We show that accurate estimates can be derived with only a small set of control points. Analysis shows that control configuration in the orientation scheme is rather flexible and that high levels of accuracy can be reached in both pose estimation and mapping. Clearly, the ability to model objects which fall outside of the immediate camera field-of-view offers an appealing means to supplement 3-D reconstruction and modeling.

  8. Monocular three-dimensional human pose estimation using local-topology preserved sparse retrieval

    NASA Astrophysics Data System (ADS)

    Yu, Jialin; Sun, Jifeng; Song, Zhiguo; Zheng, Shaoyin; Wei, Bingtian

    2017-05-01

    Estimating three-dimensional (3-D) pose from a single image is usually performed by retrieving pose candidates with two-dimensional (2-D) features. However, pose retrieval usually relies on the acquisition of sufficient labeled data and suffers from low retrieving accuracy. Acquiring a large amount of unconstrained 2-D images annotated with 3-D poses is difficult. To solve these issues, we propose a coupled-source framework that integrates two independent training sources. The first source contains only 3-D poses, and the second source contains images annotated with 2-D poses. For accurate retrieval, we present a local-topology preserved sparse coding (LTPSC) to generate pose candidates, where the estimated 2-D pose of a test image is regarded as features for pose retrieval and represented as a sparse combination of features in the exemplar database. Our LTPSC can ensure that the semantically similar poses are retrieved with larger probabilities. Extensive experiments validate the effectiveness of our method.

  9. Far and proximity maneuvers of a constellation of service satellites and autonomous pose estimation of customer satellite using machine vision

    NASA Astrophysics Data System (ADS)

    Arantes, Gilberto, Jr.; Marconi Rocco, Evandro; da Fonseca, Ijar M.; Theil, Stephan

    2010-05-01

    Space robotics has a substantial interest in achieving on-orbit satellite servicing operations autonomously, e.g. rendezvous and docking/berthing (RVD) with customer and malfunctioning satellites. An on-orbit servicing vehicle requires the ability to estimate the position and attitude in situations whenever the targets are uncooperative. Such situation comes up when the target is damaged. In this context, this work presents a robust autonomous pose system applied to RVD missions. Our approach is based on computer vision, using a single camera and some previous knowledge of the target, i.e. the customer spacecraft. A rendezvous analysis mission tool for autonomous service satellite has been developed and presented, for far maneuvers, e.g. distance above 1 km from the target, and close maneuvers. The far operations consist of orbit transfer using the Lambert formulation. The close operations include the inspection phase (during which the pose estimation is computed) and the final approach phase. Our approach is based on the Lambert problem for far maneuvers and the Hill equations are used to simulate and analyze the approaching and final trajectory between target and chase during the last phase of the rendezvous operation. A method for optimally estimating the relative orientation and position between camera system and target is presented in detail. The target is modelled as an assembly of points. The pose of the target is represented by dual quaternion in order to develop a simple quadratic error function in such a way that the pose estimation task becomes a least square minimization problem. The problem of pose is solved and some methods of non-linear square optimization (Newton, Newton-Gauss, and Levenberg-Marquard) are compared and discussed in terms of accuracy and computational cost.

  10. Appearance learning for 3D pose detection of a satellite at close-range

    NASA Astrophysics Data System (ADS)

    Oumer, Nassir W.; Kriegel, Simon; Ali, Haider; Reinartz, Peter

    2017-03-01

    In this paper we present a learning-based 3D detection of a highly challenging specular object exposed to a direct sunlight at very close-range. An object detection is one of the most important areas of image processing, and can also be used for initialization of local visual tracking methods. While the object detection in 3D space is generally a difficult problem, it poses more difficulties when the object is specular and exposed to the direct sunlight as in a space environment. Our solution to a such problem relies on an appearance learning of a real satellite mock-up based on a vector quantization and the vocabulary tree. Our method, implemented on a standard computer (CPU), exploits a full perspective projection model and provides near real-time 3D pose detection of a satellite for close-range approach and manipulation. The time consuming part of the training (feature description, building the vocabulary tree and indexing, depth buffering and back-projection) are performed offline, while a fast image retrieval and 3D-2D registration are performed on-line. In contrast, the state of the art image-based 3D pose detection methods are slower on CPU or assume a weak perspective camera projection model. In our case the dimension of the satellite is larger than the distance to the camera, hence the assumption of the weak perspective model does not hold. To evaluate the proposed method, the appearance of a full scale mock-up of the rear part of the TerraSAR-X satellite is trained under various illumination and camera views. The training images are captured with a camera mounted on six degrees of freedom robot, which enables to position the camera in a desired view, sampled over a sphere. The views that are not within the workspace of the robot are interpolated using image-based rendering. Moreover, we generate ground truth poses to verify the accuracy of the detection algorithm. The achieved results are robust and accurate even under noise due to specular reflection

  11. Key participants in codeveloped technology pose for group picture

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Following the presentation of the Universal Signal Conditioning Amplifier (USCA), a new piece of technology developed through a National Aeronautics and Space Administration (NASA) partnership with industry, to Kennedy Space Center (KSC) Director Roy Bridges, Jr., key participants in the partnership pose for a group portrait. They are (from left) Bill Larson, NASA; Dr. Pedro Medelius, INET; Roy Bridges, Jr., KSC Director; Ed Gladney and William Saputo, L-3 Communications; Pam Gillespi, representing Congressman Dave Weldon; and Frank Kinney, Technological Research and Development Authority. The USCA is a key component of the codeveloped Automated Data Acquisition System (ADAS) that measures temperature, pressure and vibration at KSC's launch pads. The breakthrough technology is expected to reduce sensor setup and configuration times from hours to seconds. KSC teamed up with Florida's Technological Research and Development Authority and manufacturer L-3 Communications to produce a system that would benefit the aerospace industry and other commercial markets.

  12. Apollo 11 Mission image - Astronaut Edwin Aldrin poses beside th

    NASA Image and Video Library

    1969-07-21

    AS11-40-5874 (20 July 1969) --- Astronaut Edwin E. Aldrin Jr., lunar module pilot of the first lunar landing mission, poses for a photograph beside the deployed United States flag during Apollo 11 extravehicular activity (EVA) on the lunar surface. The Lunar Module (LM) is on the left, and the footprints of the astronauts are clearly visible in the soil of the moon. Astronaut Neil A. Armstrong, commander, took this picture with a 70mm Hasselblad lunar surface camera. While astronauts Armstrong and Aldrin descended in the LM the "Eagle" to explore the Sea of Tranquility region of the moon, astronaut Michael Collins, command module pilot, remained with the Command and Service Modules (CSM) "Columbia" in lunar orbit.

  13. STS-110 and Expedition Four Crews Pose for Onboard Portrait

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Posed inside the Destiny Laboratory aboard the International Space Station (ISS) are the STS-110 and Expedition Four crews for a traditional onboard portrait From the left, bottom row, are astronauts Ellen Ochoa, STS mission specialist, Michael J. Bloomfield, STS mission commander, and Yury I Onufrienko, Expedition Four mission commander. From the left, middle row, are astronauts Daniel W. Bursch, Expedition Four flight engineer, Rex J. Walheim, STS mission specialist, and Carl E. Walz, Expedition Four flight engineer. From the left, top row, are astronauts Stephen N. Frick, STS pilot; Jerry L. Ross, Lee M.E. Morin, and Steven L. Smith, all mission specialists. Launched aboard the Space Shuttle Orbiter Atlantis on April 8, 2002, the STS-110 mission crew prepared the ISS for future space walks by installing and outfitting the 43-foot-long Starboard side S0 truss and preparing the Mobile Transporter. The mission served as the 8th ISS assembly flight.

  14. Astronaut David Brown poses with ComBBat team

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Astronaut David Brown poses with members of the team known as ComBBat, representing Central Florida's Astronaut and Titusville high schools. ComBBat was teamed with Boeing at KSC and Brevard Community College. Students from all over the country are at the KSC Visitor Complex for the FIRST (For Inspiration and Recognition of Science and Technology) Southeast Regional competition being held March 9-11 in the Rocket Garden. Teams of high school students are testing the limits of their imagination using robots they have designed, with the support of business and engineering professionals and corporate sponsors, to compete in a technological battle against other schools' robots. Of the 30 high school teams competing, 16 are Florida teams co-sponsored by NASA and KSC contractors. Local high schools participating are Astronaut, Bayside, Cocoa Beach, Eau Gallie, Melbourne, Melbourne Central Catholic, Palm Bay, Rockledge, Satellite, and Titusville.

  15. STS-110 and Expedition Four Crews Pose for Onboard Portrait

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Posed inside the Destiny Laboratory aboard the International Space Station (ISS) are the STS-110 and Expedition Four crews for a traditional onboard portrait From the left, bottom row, are astronauts Ellen Ochoa, STS mission specialist, Michael J. Bloomfield, STS mission commander, and Yury I Onufrienko, Expedition Four mission commander. From the left, middle row, are astronauts Daniel W. Bursch, Expedition Four flight engineer, Rex J. Walheim, STS mission specialist, and Carl E. Walz, Expedition Four flight engineer. From the left, top row, are astronauts Stephen N. Frick, STS pilot; Jerry L. Ross, Lee M.E. Morin, and Steven L. Smith, all mission specialists. Launched aboard the Space Shuttle Orbiter Atlantis on April 8, 2002, the STS-110 mission crew prepared the ISS for future space walks by installing and outfitting the 43-foot-long Starboard side S0 truss and preparing the Mobile Transporter. The mission served as the 8th ISS assembly flight.

  16. Assessment of Risks Posed to VAD Patients During Disasters.

    PubMed

    Davis, Katherine J; O'Shea, Genevieve; Beach, Michael

    2017-04-06

    Ventricular assist devices (VADs) are an Advanced Life Support for patients with heart failure. These patients are particularly vulnerable in the event of a disaster. A hazard vulnerability analysis (HVA) was conducted to determine areas of susceptibility for these patients. Lack of electrical power, limited access to medications and anticoagulation, dehydration, extreme temperature and weather environments, conditions which predispose to infection, and evacuation transport are all identified circumstances that place these patients at an increased risk for harm and death. Future preparations in disaster planning are needed to address and mitigate these risks. Davis KJ , O'Shea G , Beach M . Assessment of risks posed to VAD patients during disasters. Prehosp Disaster Med. 2017;32(4):1-5.

  17. STS-85 crew poses at LC 39A during TCDT

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The STS-85 flight crew poses at Launch Pad 39A during a break in Terminal Countdown Demonstration Test (TCDT) activities for that mission. They are (back row, from left): Pilot Kent V. Rominger; Payload Commander N. Jan Davis; Mission Specialist Stephen K. Robinson; Payload Specialist Bjarni V. Tryggvason; Mission Specialist Robert L. Curbeam, Jr.; and Commander Curtis L. Brown, Jr. The primary payload aboard the Space Shuttle orbiter Discovery is the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere-2 (CRISTA-SPAS-2). Other payloads on the 11- day mission include the Manipulator Flight Demonstration (MFD), and Technology Applications and Science-1 (TAS-1) and International Extreme Ultraviolet Hitchhiker-2 (IEH-2) experiments.

  18. STS-106 crewmembers pose for a group photograph on Zvezda

    NASA Image and Video Library

    2000-09-13

    STS106-E-5195 (13 September 2000) --- Two cosmonauts and five astronauts pose for a tradition-based inflight crew portrait aboard the International Space Station (ISS), which is currently docked with the Space Shuttle Atlantis. Astronauts Terrence W. Wilcutt, mission commander, and Scott D. Altman (bottom center) are surrounded by the five mission specialists (counterclockwise from Wilcutt) -- cosmonaut Boris V. Morukov, astronauts Richard A. Mastracchio, Edward T. Lu and Daniel C. Burbank, along with cosmonaut Yuri I. Malenchenko. Morukov and Malenchenko represent the Russian Aviation and Space Agency. The seven had just taken a brief break from the continuing tasks they're performing to help ready the ISS for other astronauts and cosmonauts permanent habitation in the near future.

  19. Expedition Three crew poses for photo on Fixed Service structure

    NASA Technical Reports Server (NTRS)

    2001-01-01

    KENNEDY SPACE CENTER, Fla. -- The Expedition Three crew poses on the Fixed Service Structure at Launch Pad 39A. From left are cosmonaut Mikhail Tyurin, commander Frank Culbertson and cosmonaut Vladimir Nikolaevich Dezhurov. The STS-105 and Expedition Three crews are at Kennedy Space Center participating in a Terminal Countdown Demonstration Test, a dress rehearsal for launch. The activities include emergency egress training, a simulated launch countdown and familiarization with the payload. Mission STS-105 will be transporting the Expedition Three crew, several payloads and scientific experiments to the International Space Station aboard Space Shuttle Discovery. The Expedition Two crew members currently on the Station will return to Earth on Discovery. The mission is scheduled to launch no earlier than Aug. 9, 2001.

  20. STS-105 crew poses for photo on Fixed Service Structure

    NASA Technical Reports Server (NTRS)

    2001-01-01

    KENNEDY SPACE CENTER, Fla. -- The STS-105 crew poses on the Fixed Service Structure at Launch Pad 39A. From left are Mission Specialist Patrick Forrester, Commander Scott Horowitz, Pilot Rick Sturckow and Mission Specialist Dan Barry. The STS-105 and Expedition Three crews are at Kennedy Space Center participating in a Terminal Countdown Demonstration Test, a dress rehearsal for launch. The activities include emergency egress training, a simulated launch countdown and familiarization with the payload. Mission STS-105 will be transporting the Expedition Three crew, several payloads and scientific experiments to the International Space Station aboard Space Shuttle Discovery. The Expedition Two crew members currently on the Station will return to Earth on Discovery. The mission is scheduled to launch no earlier than Aug. 9, 2001.

  1. Key participants in codeveloped technology pose for group picture

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Following the presentation of the Universal Signal Conditioning Amplifier (USCA), a new piece of technology developed through a National Aeronautics and Space Administration (NASA) partnership with industry, to Kennedy Space Center (KSC) Director Roy Bridges, Jr., key participants in the partnership pose for a group portrait. They are (from left) Bill Larson, NASA; Dr. Pedro Medelius, INET; Roy Bridges, Jr., KSC Director; Ed Gladney and William Saputo, L-3 Communications; Pam Gillespi, representing Congressman Dave Weldon; and Frank Kinney, Technological Research and Development Authority. The USCA is a key component of the codeveloped Automated Data Acquisition System (ADAS) that measures temperature, pressure and vibration at KSC's launch pads. The breakthrough technology is expected to reduce sensor setup and configuration times from hours to seconds. KSC teamed up with Florida's Technological Research and Development Authority and manufacturer L-3 Communications to produce a system that would benefit the aerospace industry and other commercial markets.

  2. Intrinsic feature-based pose measurement for imaging motion compensation

    DOEpatents

    Baba, Justin S.; Goddard, Jr., James Samuel

    2014-08-19

    Systems and methods for generating motion corrected tomographic images are provided. A method includes obtaining first images of a region of interest (ROI) to be imaged and associated with a first time, where the first images are associated with different positions and orientations with respect to the ROI. The method also includes defining an active region in the each of the first images and selecting intrinsic features in each of the first images based on the active region. Second, identifying a portion of the intrinsic features temporally and spatially matching intrinsic features in corresponding ones of second images of the ROI associated with a second time prior to the first time and computing three-dimensional (3D) coordinates for the portion of the intrinsic features. Finally, the method includes computing a relative pose for the first images based on the 3D coordinates.

  3. Astronaut David Brown poses with ComBBat team

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Astronaut David Brown poses with members of the team known as ComBBat, representing Central Florida's Astronaut and Titusville high schools. ComBBat was teamed with Boeing at KSC and Brevard Community College. Students from all over the country are at the KSC Visitor Complex for the FIRST (For Inspiration and Recognition of Science and Technology) Southeast Regional competition being held March 9-11 in the Rocket Garden. Teams of high school students are testing the limits of their imagination using robots they have designed, with the support of business and engineering professionals and corporate sponsors, to compete in a technological battle against other schools' robots. Of the 30 high school teams competing, 16 are Florida teams co-sponsored by NASA and KSC contractors. Local high schools participating are Astronaut, Bayside, Cocoa Beach, Eau Gallie, Melbourne, Melbourne Central Catholic, Palm Bay, Rockledge, Satellite, and Titusville.

  4. Prediction and scoring of docking poses with pyDock.

    PubMed

    Grosdidier, Solène; Pons, Carles; Solernou, Albert; Fernández-Recio, Juan

    2007-12-01

    The two previous CAPRI experiments showed the success of our rigid-body and refinement approach. For this third edition of CAPRI, we have used a new faster protocol called pyDock, which uses electrostatics and desolvation energy to score docking poses generated with FFT-based algorithms. In target T24 (unbound/model), our best prediction had the highest value of fraction of native contacts (40%) among all participants, although it was not considered as acceptable by the CAPRI criteria. In target T25 (unbound/bound), we submitted a model with medium quality. In target T26 (unbound/unbound), we did not submit any acceptable model (but we would have submitted acceptable predictions if we had included available mutational information about the binding site). For targets T27 (unbound/unbound) and T28 (homo-dimer using model), nobody (including us) submitted any acceptable model. Intriguingly, the crystal structure of target T27 shows an alternative interface that correlates with available biological data (we would have submitted acceptable predictions if we had included this). We also participated in all targets of the SCORERS experiment, with at least acceptable accuracy in all valid cases. We submitted two medium and four acceptable scoring models of T25. Using additional distance restraints (from mutational data), we had two medium and two acceptable scoring models of T26. For target T27, we submitted two acceptable scoring models of the alternative interface in the crystal structure. In summary, CAPRI showed the excellent capabilities of pyDock in identifying near-native docking poses. (c) 2007 Wiley-Liss, Inc.

  5. Level of environmental threat posed by horticultural trade in Cactaceae.

    PubMed

    Novoa, Ana; Le Roux, Johannes J; Richardson, David M; Wilson, John R U

    2017-10-01

    Ornamental horticulture has been identified as an important threat to plant biodiversity and is a major pathway for plant invasions worldwide. In this context, the family Cactaceae is particularly challenging because it is considered the fifth most threatened large taxonomic group in the world; several species are among the most widespread and damaging invasive species; and Cactaceae is one of the most popular horticultural plant groups. Based on the Convention on International Trade in Endangered Species of Wild Flora and Fauna and the 11 largest online auction sites selling cacti, we documented the international cactus trade. To provide an in-depth look at the dynamics of the industry, we surveyed the businesses involved in the cactus trade in South Africa (a hotspot of cactus trade and invasions). We purchased seeds of every available species and used DNA barcoding to identify species to the genus level. Although <20% of this trade involved threatened species and <3% involved known invasive species, many species were identified by a common name. However, only 0.02% of the globally traded cacti were collected from wild populations. Despite a large commercial network, all South African imports (of which 15% and 1.5% were of species listed as threatened and invasive, respectively) came from the same source. With DNA barcoding, we identified 24% of the species to genus level. Based on our results, we believe that if trade restrictions are placed on the small proportion of cacti that are invasive and there is no major increase in harvesting of native populations, then the commercial trade in cactus poses a negligible environmental threat. However, there are currently no effective methods for easily identifying which cacti are traded, and both the illicit harvesting of cacti from the wild and the informal trade in invasive taxa pose on-going conservation challenges. © 2017 Society for Conservation Biology.

  6. Investigation of MM-PBSA rescoring of docking poses.

    PubMed

    Thompson, David C; Humblet, Christine; Joseph-McCarthy, Diane

    2008-05-01

    Target-based virtual screening is increasingly used to generate leads for targets for which high quality three-dimensional (3D) structures are available. To allow large molecular databases to be screened rapidly, a tiered scoring scheme is often employed whereby a simple scoring function is used as a fast filter of the entire database and a more rigorous and time-consuming scoring function is used to rescore the top hits to produce the final list of ranked compounds. Molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) approaches are currently thought to be quite effective at incorporating implicit solvation into the estimation of ligand binding free energies. In this paper, the ability of a high-throughput MM-PBSA rescoring function to discriminate between correct and incorrect docking poses is investigated in detail. Various initial scoring functions are used to generate docked poses for a subset of the CCDC/Astex test set and to dock one set of actives/inactives from the DUD data set. The effectiveness of each of these initial scoring functions is discussed. Overall, the ability of the MM-PBSA rescoring function to (i) regenerate the set of X-ray complexes when docking the bound conformation of the ligand, (ii) regenerate the X-ray complexes when docking conformationally expanded databases for each ligand which include "conformation decoys" of the ligand, and (iii) enrich known actives in a virtual screen for the mineralocorticoid receptor in the presence of "ligand decoys" is assessed. While a pharmacophore-based molecular docking approach, PhDock, is used to carry out the docking, the results are expected to be general to use with any docking method.

  7. On an ill-posed model of oscillations of a flat plate with a variety of mounts on opposite sides

    NASA Astrophysics Data System (ADS)

    Iskakova, Ulzada A.

    2016-08-01

    In this paper, we consider a model case of stationary vibrations of a thin flat plate, one side of which is embedded, the opposite side is free, and the sides are freely leaned. In mathematical modeling, there is a local boundary value problem for the biharmonic equation in a rectangular domain. Boundary conditions are given on all boundary of the domain. We show that the considered problem is self-adjoint. Herewith, the problem is ill-posed. We show that the stability of solution to the problem is disturbed. Necessary and sufficient conditions of existence of the problem solution are found. Spaces of the ill-posedness of the considered problem are constructed.

  8. Inverse problems in mathematical physics

    NASA Astrophysics Data System (ADS)

    Glasko, V. B.

    Procedures for the correct formulation and solution of inverse problems, which usually belong to the class of ill-posed problems, are discussed. Attention is given to the concept of the conditionally correct statement of a problem, the concept of quasi-solution, and the fundamentals of regularization theory. The discussion also covers the uniqueness of solutions to inverse problems in mathematical physics, with consideration given to problems involving layered media, impedance problems, gravimetric problems, and inverse problems of heat conduction. The problem of stability and regularizing operators are also discussed.

  9. Assessing the risk posed by high-turbidity water to water supplies.

    PubMed

    Chang, Chia-Ling; Liao, Chung-Sheng

    2012-05-01

    The objective of this study is to assess the risk of insufficient water supply posed by high-turbidity water. Several phenomena can pose risks to the sufficiency of a water supply; this study concerns risks to water treatment plants from particular properties of rainfall and raw water turbidity. High-turbidity water can impede water treatment plant operations; rainfall properties can influence the degree of soil erosion. Thus, water turbidity relates to rainfall characteristics. Exceedance probabilities are presented for different rainfall intensities and turbidities of water. When the turbidity of raw water is higher than 5,000 NTU, it can cause operational problems for a water treatment plant. Calculations show that the turbidity of raw water at the Ban-Sin water treatment plant will be higher than 5,000 NTU if the rainfall intensity is larger than 165 mm/day. The exceedance probability of high turbidity (turbidity >5,000 NTU) in the Ban-Sin water treatment plant is larger than 10%. When any water treatment plant cannot work regularly, its ability to supply water to its customers is at risk.

  10. Robustly Aligning a Shape Model and Its Application to Car Alignment of Unknown Pose.

    PubMed

    Li, Yan; Gu, Leon; Kanade, Takeo

    2011-09-01

    Precisely localizing in an image a set of feature points that form a shape of an object, such as car or face, is called alignment. Previous shape alignment methods attempted to fit a whole shape model to the observed data, based on the assumption of Gaussian observation noise and the associated regularization process. However, such an approach, though able to deal with Gaussian noise in feature detection, turns out not to be robust or precise because it is vulnerable to gross feature detection errors or outliers resulting from partial occlusions or spurious features from the background or neighboring objects. We address this problem by adopting a randomized hypothesis-and-test approach. First, a Bayesian inference algorithm is developed to generate a shape-and-pose hypothesis of the object from a partial shape or a subset of feature points. For alignment, a large number of hypotheses are generated by randomly sampling subsets of feature points, and then evaluated to find the one that minimizes the shape prediction error. This method of randomized subset-based matching can effectively handle outliers and recover the correct object shape. We apply this approach on a challenging data set of over 5,000 different-posed car images, spanning a wide variety of car types, lighting, background scenes, and partial occlusions. Experimental results demonstrate favorable improvements over previous methods on both accuracy and robustness.

  11. A cross docking pipeline for improving pose prediction and virtual screening performance

    NASA Astrophysics Data System (ADS)

    Kumar, Ashutosh; Zhang, Kam Y. J.

    2017-08-01

    Pose prediction and virtual screening performance of a molecular docking method depend on the choice of protein structures used for docking. Multiple structures for a target protein are often used to take into account the receptor flexibility and problems associated with a single receptor structure. However, the use of multiple receptor structures is computationally expensive when docking a large library of small molecules. Here, we propose a new cross-docking pipeline suitable to dock a large library of molecules while taking advantage of multiple target protein structures. Our method involves the selection of a suitable receptor for each ligand in a screening library utilizing ligand 3D shape similarity with crystallographic ligands. We have prospectively evaluated our method in D3R Grand Challenge 2 and demonstrated that our cross-docking pipeline can achieve similar or better performance than using either single or multiple-receptor structures. Moreover, our method displayed not only decent pose prediction performance but also better virtual screening performance over several other methods.

  12. Adaptive nonlinear robust relative pose control of spacecraft autonomous rendezvous and proximity operations.

    PubMed

    Sun, Liang; Huo, Wei; Jiao, Zongxia

    2017-03-01

    This paper studies relative pose control for a rigid spacecraft with parametric uncertainties approaching to an unknown tumbling target in disturbed space environment. State feedback controllers for relative translation and relative rotation are designed in an adaptive nonlinear robust control framework. The element-wise and norm-wise adaptive laws are utilized to compensate the parametric uncertainties of chaser and target spacecraft, respectively. External disturbances acting on two spacecraft are treated as a lumped and bounded perturbation input for system. To achieve the prescribed disturbance attenuation performance index, feedback gains of controllers are designed by solving linear matrix inequality problems so that lumped disturbance attenuation with respect to the controlled output is ensured in the L2-gain sense. Moreover, in the absence of lumped disturbance input, asymptotical convergence of relative pose are proved by using the Lyapunov method. Numerical simulations are performed to show that position tracking and attitude synchronization are accomplished in spite of the presence of couplings and uncertainties. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  13. Assessing the risk posed by natural hazards to infrastructures

    NASA Astrophysics Data System (ADS)

    Eidsvig, Unni Marie K.; Kristensen, Krister; Vidar Vangelsten, Bjørn

    2017-03-01

    This paper proposes a model for assessing the risk posed by natural hazards to infrastructures, with a focus on the indirect losses and loss of stability for the population relying on the infrastructure. The model prescribes a three-level analysis with increasing level of detail, moving from qualitative to quantitative analysis. The focus is on a methodology for semi-quantitative analyses to be performed at the second level. The purpose of this type of analysis is to perform a screening of the scenarios of natural hazards threatening the infrastructures, identifying the most critical scenarios and investigating the need for further analyses (third level). The proposed semi-quantitative methodology considers the frequency of the natural hazard, different aspects of vulnerability, including the physical vulnerability of the infrastructure itself, and the societal dependency on the infrastructure. An indicator-based approach is applied, ranking the indicators on a relative scale according to pre-defined ranking criteria. The proposed indicators, which characterise conditions that influence the probability of an infrastructure malfunctioning caused by a natural event, are defined as (1) robustness and buffer capacity, (2) level of protection, (3) quality/level of maintenance and renewal, (4) adaptability and quality of operational procedures and (5) transparency/complexity/degree of coupling. Further indicators describe conditions influencing the socio-economic consequences of the infrastructure malfunctioning, such as (1) redundancy and/or substitution, (2) cascading effects and dependencies, (3) preparedness and (4) early warning, emergency response and measures. The aggregated risk estimate is a combination of the semi-quantitative vulnerability indicators, as well as quantitative estimates of the frequency of the natural hazard, the potential duration of the infrastructure malfunctioning (e.g. depending on the required restoration effort) and the number of users of

  14. 3D sensor algorithms for spacecraft pose determination

    NASA Astrophysics Data System (ADS)

    Trenkle, John M.; Tchoryk, Peter, Jr.; Ritter, Greg A.; Pavlich, Jane C.; Hickerson, Aaron S.

    2006-05-01

    Researchers at the Michigan Aerospace Corporation have developed accurate and robust 3-D algorithms for pose determination (position and orientation) of satellites as part of an on-going effort supporting autonomous rendezvous, docking and space situational awareness activities. 3-D range data from a LAser Detection And Ranging (LADAR) sensor is the expected input; however, the approach is unique in that the algorithms are designed to be sensor independent. Parameterized inputs allow the algorithms to be readily adapted to any sensor of opportunity. The cornerstone of our approach is the ability to simulate realistic range data that may be tailored to the specifications of any sensor. We were able to modify an open-source raytracing package to produce point cloud information from which high-fidelity simulated range images are generated. The assumptions made in our experimentation are as follows: 1) we have access to a CAD model of the target including information about the surface scattering and reflection characteristics of the components; 2) the satellite of interest may appear at any 3-D attitude; 3) the target is not necessarily rigid, but does have a limited number of configurations; and, 4) the target is not obscured in any way and is the only object in the field of view of the sensor. Our pose estimation approach then involves rendering a large number of exemplars (100k to 5M), extracting 2-D (silhouette- and projection-based) and 3-D (surface-based) features, and then training ensembles of decision trees to predict: a) the 4-D regions on a unit hypersphere into which the unit quaternion that represents the vehicle [Q X, Q Y, Q Z, Q W] is pointing, and, b) the components of that unit quaternion. Results have been quite promising and the tools and simulation environment developed for this application may also be applied to non-cooperative spacecraft operations, Autonomous Hazard Detection and Avoidance (AHDA) for landing craft, terrain mapping, vehicle

  15. Invasive Lionfish (Pterosis volitans) Pose Public Health Threats.

    PubMed

    Diaz, James H

    2015-01-01

    The lionfish, Pterosis volitans, a native of Indo-Pacific oceans, is a popular saltwater aquarium fish despite venomous spines on its fins. Lionfish were inadvertently introduced into the western Atlantic from Florida in the early 1990s and have overpopulated and dispersed widely into the Caribbean Sea and Gulf of Mexico. Initiatives to control lionfish populations were launched, including the National Oceanographic and Atmospheric Administration (NOAA)-sponsored "Lionfish as Food Campaign".2 Recently, scientists from the Food and Drug Administration (FDA) reported that lionfish caught off the US Virgin Islands contained ciguatoxins and could cause ciguatera fish poisoning (CFP); a seafood-borne poisoning without an antidote or any specific treatment, and a potential for prolonged neurotoxicity. Lionfish pose several public health threats. New strategies to control the lionfish population explosion in coastal waters and offshore fisheries are needed now to ensure seafood safety and public health. The lionfish, Pterosis volitans, is native to the reefs of the western Indian and Pacific Oceans (Figure 1). Brightly colored with red, white, and black stripes and adorned with feathery fins, the lionfish is a popular saltwater aquarium fish despite venomous spines on its fins (Figure 2). Lionfish were introduced into the western North Atlantic from Florida in the early 1990s after some specimens were discarded by dissatisfied amateur aquarists and others escaped from hurricane-flooded public aquariums.1 Since lionfish are voracious carnivores, have few natural predators, and reproduce prolifically, they have overpopulated and dispersed widely from Cape Hatteras to Florida, throughout the Caribbean Sea, and into the Gulf of Mexico.1 The population density of lionfish in its new, invaded territory now exceeds that of its native habitat.1 As a result, campaigns to control lionfish populations were launched in Florida and the Caribbean. Lionfish now pose several public

  16. Health Issues: Do Cell Phones Pose a Health Hazard?

    MedlinePlus

    ... problems. Cell phones emit low levels of radiofrequency energy (RF). Over the past 15 years, scientists have ... looking at the biological effects of the radiofrequency energy emitted by cell phones. While some researchers have ...

  17. Pose invariant face recognition: 3D model from single photo

    NASA Astrophysics Data System (ADS)

    Napoléon, Thibault; Alfalou, Ayman

    2017-02-01

    Face recognition is widely studied in the literature for its possibilities in surveillance and security. In this paper, we report a novel algorithm for the identification task. This technique is based on an optimized 3D modeling allowing to reconstruct faces in different poses from a limited number of references (i.e. one image by class/person). Particularly, we propose to use an active shape model to detect a set of keypoints on the face necessary to deform our synthetic model with our optimized finite element method. Indeed, in order to improve our deformation, we propose a regularization by distances on graph. To perform the identification we use the VanderLugt correlator well know to effectively address this task. On the other hand we add a difference of Gaussian filtering step to highlight the edges and a description step based on the local binary patterns. The experiments are performed on the PHPID database enhanced with our 3D reconstructed faces of each person with an azimuth and an elevation ranging from -30° to +30°. The obtained results prove the robustness of our new method with 88.76% of good identification when the classic 2D approach (based on the VLC) obtains just 44.97%.

  18. Does ketoprofen or diclofenac pose the lowest risk to fish?

    PubMed

    Cuklev, Filip; Fick, Jerker; Cvijovic, Marija; Kristiansson, Erik; Förlin, Lars; Larsson, D G Joakim

    2012-08-30

    Ketoprofen and diclofenac are non-steroidal anti-inflammatory drugs (NSAIDs) often used for similar indications, and both are frequently found in surface waters. Diclofenac affects organ histology and gene expression in fish at around 1 μg/L. Here, we exposed rainbow trout to ketoprofen (1, 10 and 100 μg/L) to investigate if this alternative causes less risk for pharmacological responses in fish. The bioconcentration factor from water to fish blood plasma was <0.05 (4 for diclofenac based on previous studies). Ketoprofen only reached up to 0.6 ‰ of the human therapeutic plasma concentration, thus the probability of target-related effects was estimated to be fairly low. Accordingly, a comprehensive analysis of hepatic gene expression revealed no consistent responses. In some contrast, trout exposed to undiluted, treated sewage effluents bioconcentrated ketoprofen and other NSAIDs much more efficiently, according to a meta-analysis of recent studies. Neither of the setups is however an ideal representation of the field situation. If a controlled exposure system with a single chemical in pure water is a reasonable representation of the environment, then the use of ketoprofen is likely to pose a lower risk for wild fish than diclofenac, but if bioconcentration factors from effluent-exposed fish are applied, the risks may be more similar.

  19. STS-95 Payload Specialist Mukai poses with NASDA president

    NASA Technical Reports Server (NTRS)

    1998-01-01

    STS-95 Payload Specialist Chiaki Mukai, M.D. (center), with the National Space Development Agency of Japan (NASDA), poses for a photograph with NASDA President Isao Uchida (left). Behind her at the right is a representative of the European Space Agency (ESA). Mukai was one of a crew of seven aboard orbiter Discovery, which landed at KSC at 12:04 p.m. EST, after a successful mission spanning nine days and 3.6 million miles. The other crew members are Mission Commander Curtis L. Brown Jr.; Pilot Steven W. Lindsey; Mission Specialists Stephen K. Robinson; Scott E. Parazynski and Pedro Duque of Spain, with the European Space Agency; and Payload Specialist John H. Glenn Jr., senator from Ohio. The mission included research payloads such as the Spartan solar-observing deployable spacecraft, the Hubble Space Telescope Orbital Systems Test Platform, the International Extreme Ultraviolet Hitchhiker, as well as the SPACEHAB single module with experiments on space flight and the aging process.

  20. Reappraisal of biosafety risks posed by PERVs in xenotransplantation.

    PubMed

    Louz, Derrick; Bergmans, Hans E; Loos, Birgit P; Hoeben, Rob C

    2008-01-01

    Donor materials of porcine origin could potentially provide an alternative source of cells, tissues or whole organs for transplantation to humans, but is hampered by the health risk posed by infection with porcine viruses. Although pigs can be bred in such a way that all known exogenous microorganisms are eliminated, this is not feasible for all endogenous pathogens, such as the porcine endogenous retroviruses (PERVs) which are present in the germline of pigs as proviruses. Upon transplantation, PERV proviruses would be transferred to the human recipient along with the xenograft. If xenotransplantation stimulates or facilitates replication of PERVs in the new hosts, a risk exists for adaptation of the virus to humans and subsequent spread of these viruses. In a worst-case scenario, this might result in the emergence of a new viral disease. Although the concerns for disease potential of PERVs are easing, only limited pre-clinical and clinical data are available. Small-scale, well-designed and carefully controlled clinical trials would provide more evidence on the safety of this approach and allow a better appreciation of the risks involved. It is therefore important to have a framework of protective measures and monitoring protocols in place to facilitate such initially small scale clinical trials. This framework will raise ethical and social considerations regarding acceptability. John Wiley & Sons, Ltd

  1. Real-time pose invariant logo and pattern detection

    NASA Astrophysics Data System (ADS)

    Sidla, Oliver; Kottmann, Michal; Benesova, Wanda

    2011-01-01

    The detection of pose invariant planar patterns has many practical applications in computer vision and surveillance systems. The recognition of company logos is used in market studies to examine the visibility and frequency of logos in advertisement. Danger signs on vehicles could be detected to trigger warning systems in tunnels, or brand detection on transport vehicles can be used to count company-specific traffic. We present the results of a study on planar pattern detection which is based on keypoint detection and matching of distortion invariant 2d feature descriptors. Specifically we look at the keypoint detectors of type: i) Lowe's DoG approximation from the SURF algorithm, ii) the Harris Corner Detector, iii) the FAST Corner Detector and iv) Lepetit's keypoint detector. Our study then compares the feature descriptors SURF and compact signatures based on Random Ferns: we use 3 sets of sample images to detect and match 3 logos of different structure to find out which combinations of keypoint detector/feature descriptors work well. A real-world test tries to detect vehicles with a distinctive logo in an outdoor environment under realistic lighting and weather conditions: a camera was mounted on a suitable location for observing the entrance to a parking area so that incoming vehicles could be monitored. In this 2 hour long recording we can successfully detect a specific company logo without false positives.

  2. Quantifying the Risk Posed by Potential Earth Impacts

    NASA Astrophysics Data System (ADS)

    Chesley, Steven R.; Chodas, Paul W.; Milani, Andrea; Valsecchi, Giovanni B.; Yeomans, Donald K.

    2002-10-01

    Predictions of future potential Earth impacts by near-Earth objects (NEOs) have become commonplace in recent years, and the rate of these detections is likely to accelerate as asteroid survey efforts continue to mature. In order to conveniently compare and categorize the numerous potential impact solutions being discovered we propose a new hazard scale that will describe the risk posed by a particular potential impact in both absolute and relative terms. To this end, we measure each event in two ways, first without any consideration of the event's time proximity or its significance relative to the so-called background threat, and then in the context of the expected risk from other objects over the intervening years until the impact. This approach is designed principally to facilitate communication among astronomers, and it is not intended for public communication of impact risks. The scale characterizes impacts across all impact energies, probabilities and dates, and it is useful, in particular, when dealing with those cases which fall below the threshold of public interest. The scale also reflects the urgency of the situation in a natural way and thus can guide specialists in assessing the computational and observational effort appropriate for a given situation. In this paper we describe the metrics introduced, and we give numerous examples of their application. This enables us to establish in rough terms the levels at which events become interesting to various parties.

  3. STS-95 Payload Specialist Mukai poses with NASDA president

    NASA Technical Reports Server (NTRS)

    1998-01-01

    STS-95 Payload Specialist Chiaki Mukai, M.D. (center), with the National Space Development Agency of Japan (NASDA), poses for a photograph with NASDA President Isao Uchida (left). Behind her at the right is a representative of the European Space Agency (ESA). Mukai was one of a crew of seven aboard orbiter Discovery, which landed at KSC at 12:04 p.m. EST, after a successful mission spanning nine days and 3.6 million miles. The other crew members are Mission Commander Curtis L. Brown Jr.; Pilot Steven W. Lindsey; Mission Specialists Stephen K. Robinson; Scott E. Parazynski and Pedro Duque of Spain, with the European Space Agency; and Payload Specialist John H. Glenn Jr., senator from Ohio. The mission included research payloads such as the Spartan solar-observing deployable spacecraft, the Hubble Space Telescope Orbital Systems Test Platform, the International Extreme Ultraviolet Hitchhiker, as well as the SPACEHAB single module with experiments on space flight and the aging process.

  4. The STS-93 crew pose in front of Columbia

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The STS-93 crew pose in front of the Space Shuttle orbiter Columbia following their landing on runway 33 at the Shuttle Landing Facility. Main gear touchdown occurred at 11:20:35 p.m. EDT on July 27. From left to right, they are Mission Specialists Catherine G. Coleman (Ph.D.) and Stephen A. Hawley (Ph.D.), Pilot Jeffrey S. Ashby, Commander Eileen Collins, and Mission Specialist Michel Tognini of France, with the Centre National d'Etudes Spatiales (CNES). The mission's primary objective was to deploy the Chandra X-ray Observatory, which will allow scientists from around the world to study some of the most distant, powerful and dynamic objects in the universe. This was the 95th flight in the Space Shuttle program and the 26th for Columbia. The landing was the 19th consecutive Shuttle landing in Florida and the 12th night landing in Shuttle program history. On this mission, Collins became the first woman to serve as a Shuttle commander.

  5. Natural pixel decomposition for interferometric tomographic reconstruction from ill-posed data

    NASA Astrophysics Data System (ADS)

    Cha, D. J.; Cha, S. S.

    Reconstruction of three-dimensional refractive-index fields from multidirectional holographic interferograms can be a powerful flow diagnostic tool in many engineering applications. It is noninvasive and can capture gross fields instantaneously. Interferometric tomography for reconstructing flow fields, however, confronts ill-posed problems, that is, last of sufficient data. As the flow fields are sampled in the presence of opaque models and enclosures, the data are sparse, nonuniform, and sometimes incomplete in projection and scanning. Here, a new method, termed the variable grid method, to incorporate the distinct features of interferometric data for flow field reconstruction is developed and tested. The method is based on natural pixel decomposition. It utilizes variable rectangular grid elements in representing a field with a finite series. The variable grid method allows better reconstruction resolution with greater accuracy in the region where sampled rays are more closely crossed. This region is usually of interest in engineering.

  6. A globally well-posed finite element algorithm for aerodynamics applications

    NASA Technical Reports Server (NTRS)

    Iannelli, G. S.; Baker, A. J.

    1991-01-01

    A finite element CFD algorithm is developed for Euler and Navier-Stokes aerodynamic applications. For the linear basis, the resultant approximation is at least second-order-accurate in time and space for synergistic use of three procedures: (1) a Taylor weak statement, which provides for derivation of companion conservation law systems with embedded dispersion-error control mechanisms; (2) a stiffly stable second-order-accurate implicit Rosenbrock-Runge-Kutta temporal algorithm; and (3) a matrix tensor product factorization that permits efficient numerical linear algebra handling of the terminal large-matrix statement. Thorough analyses are presented regarding well-posed boundary conditions for inviscid and viscous flow specifications. Numerical solutions are generated and compared for critical evaluation of quasi-one- and two-dimensional Euler and Navier-Stokes benchmark test problems.

  7. Well-posed Euler model of shock-induced two-phase flow in bubbly liquid

    NASA Astrophysics Data System (ADS)

    Tukhvatullina, R. R.; Frolov, S. M.

    2017-07-01

    A well-posed mathematical model of non-isothermal two-phase two-velocity flow of bubbly liquid is proposed. The model is based on the two-phase Euler equations with the introduction of an additional pressure at the gas bubble surface, which ensures the well-posedness of the Cauchy problem for a system of governing equations with homogeneous initial conditions, and the Rayleigh-Plesset equation for radial pulsations of gas bubbles. The applicability conditions of the model are formulated. The model is validated by comparing one-dimensional calculations of shock wave propagation in liquids with gas bubbles with a gas volume fraction of 0.005-0.3 with experimental data. The model is shown to provide satisfactory results for the shock propagation velocity, pressure profiles, and the shock-induced motion of the bubbly liquid column.

  8. Semi-automatic identification photo generation with facial pose and illumination normalization

    NASA Astrophysics Data System (ADS)

    Jiang, Bo; Liu, Sijiang; Wu, Song

    2016-07-01

    Identification photo is a category of facial image that has strict requirements on image quality like size, illumination, user expression, dressing, etc. Traditionally, these photos are taken in professional studios. With the rapid popularity of mobile devices, how to conveniently take identification photo at any time and anywhere with such devices is an interesting problem. In this paper, we propose a novel semi-automatic identification photo generation approach. Given a user image, facial pose and expression are first normalized to meet the basic requirements. To correct uneven lighting condition in photo, an facial illumination normalization approach is adopted to further improve the image quality. Finally, foreground user is extracted and re-targeted to a specific photo size. Besides, background can also be changed as required. Preliminary experimental results show that the proposed method is efficient and effective in identification photo generation compared to commercial software based manual tunning.

  9. Lossless divide and conquer for time-order sorting of N facial poses

    NASA Astrophysics Data System (ADS)

    Hsu, Ming Kai; Szu, Harold

    2011-06-01

    Law enforcement agencies need a quick decision in May 1 2010 NY Time Square for quickly spot wanted car bomb individuals in a crowd. This goal requires real-time smart firmware and a smart search algorithm to know how to order the faces in a geometric way. We demonstrate such a sorting problem of N facial poses time ordering is like the TSP of N cities, NP-complete, having no exact deterministic solution. Here we demonstrated a heuristic working solution to answer the ONR grand challenge called Empire 2010. How could the N boxes of faces detected and cut by the efficient COST parallel color-hue-algorithm, without time mark, at a single CPU (or even with the time marks but collected videos from multiple vintage points) to determine automatically who speaks what, where, and when? There must be a cross platform sensory association from our different sensors.

  10. On Euler's problem

    SciTech Connect

    Egorov, Yurii V

    2013-04-30

    We consider the classical problem on the tallest column which was posed by Euler in 1757. Bernoulli-Euler theory serves today as the basis for the design of high buildings. This problem is reduced to the problem of finding the potential for the Sturm-Liouville equation corresponding to the maximum of the first eigenvalue. The problem has been studied by many mathematicians but we give the first rigorous proof of the existence and uniqueness of the optimal column and we give new formulae which let us find it. Our method is based on a new approach consisting in the study of critical points of a related nonlinear functional. Bibliography: 6 titles.

  11. Sinc-Galerkin Estimation of Diffusivity in Parabolic Problems

    DTIC Science & Technology

    1991-05-01

    1977 Solutions of Ill - Posed Problems (New York: Wiley) [20] Wahba G 1977 Practical approximate solutions to linear operator equations when the data...reasons. As indicated in [121, the problem is ill - posed in the sense that solutions p (provided they exist) may not depend continuously on the data d... posedness and convergence of some regular- ization methods for nonlinear ill - posed problems Inv. Prob. 5 227-238 (16

  12. Allocation Games: Addressing the Ill-Posed Nature of Allocation in Life-Cycle Inventories.

    PubMed

    Hanes, Rebecca J; Cruze, Nathan B; Goel, Prem K; Bakshi, Bhavik R

    2015-07-07

    Allocation is required when a life cycle contains multi-functional processes. One approach to allocation is to partition the embodied resources in proportion to a criterion, such as product mass or cost. Many practitioners apply multiple partitioning criteria to avoid choosing one arbitrarily. However, life cycle results from different allocation methods frequently contradict each other, making it difficult or impossible for the practitioner to draw any meaningful conclusions from the study. Using the matrix notation for life-cycle inventory data, we show that an inventory that requires allocation leads to an ill-posed problem: an inventory based on allocation is one of an infinite number of inventories that are highly dependent upon allocation methods. This insight is applied to comparative life-cycle assessment (LCA), in which products with the same function but different life cycles are compared. Recently, there have been several studies that applied multiple allocation methods and found that different products were preferred under different methods. We develop the Comprehensive Allocation Investigation Strategy (CAIS) to examine any given inventory under all possible allocation decisions, enabling us to detect comparisons that are not robust to allocation, even when the comparison appears robust under conventional partitioning methods. While CAIS does not solve the ill-posed problem, it provides a systematic way to parametrize and examine the effects of partitioning allocation. The practical usefulness of this approach is demonstrated with two case studies. The first compares ethanol produced from corn stover hydrolysis, corn stover gasification, and corn grain fermentation. This comparison was not robust to allocation. The second case study compares 1,3-propanediol (PDO) produced from fossil fuels and from biomass, which was found to be a robust comparison.

  13. Choosing parameters of kernel subspace LDA for recognition of face images under pose and illumination variations.

    PubMed

    Huang, Jian; Yuen, Pong C; Chen, Wen-Sheng; Lai, Jian Huang

    2007-08-01

    This paper addresses the problem of automatically tuning multiple kernel parameters for the kernel-based linear discriminant analysis (LDA) method. The kernel approach has been proposed to solve face recognition problems under complex distribution by mapping the input space to a high-dimensional feature space. Some recognition algorithms such as the kernel principal components analysis, kernel Fisher discriminant, generalized discriminant analysis, and kernel direct LDA have been developed in the last five years. The experimental results show that the kernel-based method is a good and feasible approach to tackle the pose and illumination variations. One of the crucial factors in the kernel approach is the selection of kernel parameters, which highly affects the generalization capability and stability of the kernel-based learning methods. In view of this, we propose an eigenvalue-stability-bounded margin maximization (ESBMM) algorithm to automatically tune the multiple parameters of the Gaussian radial basis function kernel for the kernel subspace LDA (KSLDA) method, which is developed based on our previously developed subspace LDA method. The ESBMM algorithm improves the generalization capability of the kernel-based LDA method by maximizing the margin maximization criterion while maintaining the eigenvalue stability of the kernel-based LDA method. An in-depth investigation on the generalization performance on pose and illumination dimensions is performed using the YaleB and CMU PIE databases. The FERET database is also used for benchmark evaluation. Compared with the existing PCA-based and LDA-based methods, our proposed KSLDA method, with the ESBMM kernel parameter estimation algorithm, gives superior performance.

  14. An investigation into multi-dimensional prediction models to estimate the pose error of a quadcopter in a CSP plant setting

    NASA Astrophysics Data System (ADS)

    Lock, Jacobus C.; Smit, Willie J.; Treurnicht, Johann

    2016-05-01

    The Solar Thermal Energy Research Group (STERG) is investigating ways to make heliostats cheaper to reduce the total cost of a concentrating solar power (CSP) plant. One avenue of research is to use unmanned aerial vehicles (UAVs) to automate and assist with the heliostat calibration process. To do this, the pose estimation error of each UAV must be determined and integrated into a calibration procedure. A computer vision (CV) system is used to measure the pose of a quadcopter UAV. However, this CV system contains considerable measurement errors. Since this is a high-dimensional problem, a sophisticated prediction model must be used to estimate the measurement error of the CV system for any given pose measurement vector. This paper attempts to train and validate such a model with the aim of using it to determine the pose error of a quadcopter in a CSP plant setting.

  15. Making Faces: Age and Emotion Differences in the Posing of Emotional Expressions.

    ERIC Educational Resources Information Center

    Lewis, Michael; And Others

    1987-01-01

    Videotape study of preschool children, two to five years of age, and adults who posed the six facial expressions of happiness, surprise, anger, fear, sadness, and disgust. Poses were scored using the MAX system. Results showed that consistent differences between partial and complete poses were observed for negative expressions. (Author/RWB)

  16. The challenge posed by endocrine-disrupting chemicals.

    PubMed

    Ashby, J; Houthoff, E; Kennedy, S J; Stevens, J; Bars, R; Jekat, F W; Campbell, P; Van Miller, J; Carpanini, F M; Randall, G L

    1997-02-01

    Rapid regulatory developments in the area of environmental endocrine disruption present a series of potential problems that are identified and illustrated with examples taken from the recent literature. A list of priorities is provided, including the need for additional epidemiological and wildlife studies, the derivation of a coordinated testing strategy, agreement on the toxicities expected of endocrine disrupting agents, and acceptance that whole animal assays will be uniquely critical in this area of toxicology. The intrinsic difficulty of attempting to simultaneously study all aspects of endocrine disruption indicates the need to reduce the scope of the problem, which can be achieved by first studying toxicities mediated by sex hormone receptors.

  17. The challenge posed by endocrine-disrupting chemicals.

    PubMed Central

    Ashby, J; Houthoff, E; Kennedy, S J; Stevens, J; Bars, R; Jekat, F W; Campbell, P; Van Miller, J; Carpanini, F M; Randall, G L

    1997-01-01

    Rapid regulatory developments in the area of environmental endocrine disruption present a series of potential problems that are identified and illustrated with examples taken from the recent literature. A list of priorities is provided, including the need for additional epidemiological and wildlife studies, the derivation of a coordinated testing strategy, agreement on the toxicities expected of endocrine disrupting agents, and acceptance that whole animal assays will be uniquely critical in this area of toxicology. The intrinsic difficulty of attempting to simultaneously study all aspects of endocrine disruption indicates the need to reduce the scope of the problem, which can be achieved by first studying toxicities mediated by sex hormone receptors. PMID:9105789

  18. Crisis planning to manage risks posed by animal rights extremists.

    PubMed

    Bailey, Matthew R; Rich, Barbara A; Bennett, B Taylor

    2010-01-01

    Among the multitude of crises that US research institutions may face are those caused by animal rights activists. While most activists opposed to animal research use peaceful and lawful means of expressing their opinions, some extremists resort to illegal methods. Arson, break-ins, and theft with significant property damage at US animal research facilities began in the 1980s. The most troubling trend to develop in the past decade is the targeting of individuals associated with animal research, whether directly or indirectly, and the use of violent scare tactics to intimidate researchers and their families. The National Association for Biomedical Research has a 30-year history of monitoring the animal rights movement and assisting member institutions with crisis situations. In this article we discuss attacks on researchers at their homes, cyber crimes, exploitation of new media formats, infiltration of research facilities, and the targeting of external research stakeholders and business partners. We describe the need for a well-conceived crisis management plan and strong leadership to mitigate crisis situations. Institutions with well-informed leaders and crisis management teams ready to take timely action are best equipped to protect staff, laboratory animals, and research programs. They act on early warnings, provide support for targeted staff, seek legal remedies, thoughtfully control access to research facilities, and identify and enlist new research supporters. We underscore the importance of up-to-date crisis planning so that institutions are not only aware of ongoing risks posed by animal rights extremists but also better prepared to take preemptive action and able to manage those risks successfully.

  19. Internet poses multiple risks to children and adolescents.

    PubMed

    McColgan, Maria D; Giardino, Angelo P

    2005-05-01

    Computers and Internet usage, whether by children at home or at public places such as schools and libraries, are here to stay. Tremendous benefits in terms of educational opportunities, communication, and recreation can be expected. With all the benefits that such information technology provides, however, there is an element of risk that should not inhibit its use but must be attended to and managed. The methods child sexual offenders use to pursue their criminal interests will continue to evolve as technology evolves. The first and most important line of defense calls for parents and other caregivers to remain directly responsible for the safety of the children in their care. Parents, teachers, healthcare providers, and other caregivers need to learn continually about the Internet and remain aware of how best to protect children who use the computer and the Internet. Law enforcement agencies must also continue to prepare for advances in computer technology, to better anticipate the behavior of child sexual offenders, and to investigate and prosecute offenders. All law enforcement, medical, and social services personnel who have contact with children on a regular basis must continue to educate children and their parents or guardians about the dangers posed by the Internet. After a child is victimized, law enforcement, medical, and social services personnel also must remain cognizant that the victim's computer may contain evidence that may help identify and prosecute the offender. In short, all those charged with the protection of children and the prosecution of child sexual offenders must continue to adapt to our ever-evolving computer technology.

  20. STS-103 crew pose in front of Pad 39B

    NASA Technical Reports Server (NTRS)

    1999-01-01

    During Terminal Countdown Demonstration Test (TDCT) activities at Launch Pad 39B, the STS-103 crew pose in front of the flame trench, which is situated underneath the Mobile Launcher Platform holding Space Shuttle Discovery. Standing left to right are Mission Specialists Claude Nicollier of Switzerland, who is with the European Space Agency (ESA), C. Michael Foale (Ph.D.), John M. Grunsfeld (Ph.D.), Pilot Scott J. Kelly, Commander Curtis L. Brown Jr., and Mission Specialists Jean-Frangois Clervoy of France, also with ESA, and Steven L. Smith. One of the solid rocket boosters and the external tank that are attached to Discovery can be seen in the photo. The flame trench is made of concrete and refractory brick, and contains an orbiter flame deflector on one side and solid rocket booster flame deflector on the other. The deflectors protect the flame trench floor and pad surface from the intense heat of launch. The TCDT provides the crew with emergency egress training, opportunities to inspect their mission payloads in the orbiter's payload bay, and simulated countdown exercises. STS-103 is a 'call-up' mission due to the need to replace and repair portions of the Hubble Space Telescope, including the gyroscopes that allow the telescope to point at stars, galaxies and planets. The STS-103 crew will be replacing a Fine Guidance Sensor, an older computer with a new enhanced model, an older data tape recorder with a solid-state digital recorder, a failed spare transmitter with a new one, and degraded insulation on the telescope with new thermal insulation. The crew will also install a Battery Voltage/Temperature Improvement Kit to protect the spacecraft batteries from overcharging and overheating when the telescope goes into a safe mode. Four EVA's are planned to make the necessary repairs and replacements on the telescope. The mission is targeted for launch Dec. 6 at 2:37 a.m. EST.

  1. Assessing the risk posed by natural hazards to infrastructures

    NASA Astrophysics Data System (ADS)

    Eidsvig, Unni; Kristensen, Krister; Vidar Vangelsten, Bjørn

    2015-04-01

    The modern society is increasingly dependent on infrastructures to maintain its function, and disruption in one of the infrastructure systems may have severe consequences. The Norwegian municipalities have, according to legislation, a duty to carry out a risk and vulnerability analysis and plan and prepare for emergencies in a short- and long term perspective. Vulnerability analysis of the infrastructures and their interdependencies is an important part of this analysis. This paper proposes a model for assessing the risk posed by natural hazards to infrastructures. The model prescribes a three level analysis with increasing level of detail, moving from qualitative to quantitative analysis. This paper focuses on the second level, which consists of a semi-quantitative analysis. The purpose of this analysis is to perform a screening of the scenarios of natural hazards threatening the infrastructures identified in the level 1 analysis and investigate the need for further analyses, i.e. level 3 quantitative analyses. The proposed level 2 analysis considers the frequency of the natural hazard, different aspects of vulnerability including the physical vulnerability of the infrastructure itself and the societal dependency on the infrastructure. An indicator-based approach is applied, ranking the indicators on a relative scale. The proposed indicators characterize the robustness of the infrastructure, the importance of the infrastructure as well as interdependencies between society and infrastructure affecting the potential for cascading effects. Each indicator is ranked on a 1-5 scale based on pre-defined ranking criteria. The aggregated risk estimate is a combination of the semi-quantitative vulnerability indicators, as well as quantitative estimates of the frequency of the natural hazard and the number of users of the infrastructure. Case studies for two Norwegian municipalities are presented, where risk to primary road, water supply and power network threatened by storm

  2. STS-103 crew pose in front of Pad 39B

    NASA Technical Reports Server (NTRS)

    1999-01-01

    During Terminal Countdown Demonstration Test (TDCT) activities at Launch Pad 39B, the STS-103 crew pose in front of the flame trench, which is situated underneath the Mobile Launcher Platform holding Space Shuttle Discovery. Standing left to right are Mission Specialists Claude Nicollier of Switzerland, who is with the European Space Agency (ESA), C. Michael Foale (Ph.D.), John M. Grunsfeld (Ph.D.), Pilot Scott J. Kelly, Commander Curtis L. Brown Jr., and Mission Specialists Jean-Frangois Clervoy of France, also with ESA, and Steven L. Smith. One of the solid rocket boosters and the external tank that are attached to Discovery can be seen in the photo. The flame trench is made of concrete and refractory brick, and contains an orbiter flame deflector on one side and solid rocket booster flame deflector on the other. The deflectors protect the flame trench floor and pad surface from the intense heat of launch. The TCDT provides the crew with emergency egress training, opportunities to inspect their mission payloads in the orbiter's payload bay, and simulated countdown exercises. STS-103 is a 'call-up' mission due to the need to replace and repair portions of the Hubble Space Telescope, including the gyroscopes that allow the telescope to point at stars, galaxies and planets. The STS-103 crew will be replacing a Fine Guidance Sensor, an older computer with a new enhanced model, an older data tape recorder with a solid-state digital recorder, a failed spare transmitter with a new one, and degraded insulation on the telescope with new thermal insulation. The crew will also install a Battery Voltage/Temperature Improvement Kit to protect the spacecraft batteries from overcharging and overheating when the telescope goes into a safe mode. Four EVA's are planned to make the necessary repairs and replacements on the telescope. The mission is targeted for launch Dec. 6 at 2:37 a.m. EST.

  3. Problem Effectiveness in a Course Using Problem-Based Learning.

    ERIC Educational Resources Information Center

    Dolmans, Diana H. J. M.

    1993-01-01

    A University of Limburg (Netherlands) medical school study investigated the relationship between student-generated learning issues and faculty instructional objectives (i.e., the effectiveness of the problems posed) in a problem-centered obstetrics and child development curriculum. Subjects were 120 students and 12 faculty. Results indicated…

  4. A nonrigid kernel-based framework for 2D-3D pose estimation and 2D image segmentation.

    PubMed

    Sandhu, Romeil; Dambreville, Samuel; Yezzi, Anthony; Tannenbaum, Allen

    2011-06-01

    In this work, we present a nonrigid approach to jointly solving the tasks of 2D-3D pose estimation and 2D image segmentation. In general, most frameworks that couple both pose estimation and segmentation assume that one has exact knowledge of the 3D object. However, under nonideal conditions, this assumption may be violated if only a general class to which a given shape belongs is given (e.g., cars, boats, or planes). Thus, we propose to solve the 2D-3D pose estimation and 2D image segmentation via nonlinear manifold learning of 3D embedded shapes for a general class of objects or deformations for which one may not be able to associate a skeleton model. Thus, the novelty of our method is threefold: first, we present and derive a gradient flow for the task of nonrigid pose estimation and segmentation. Second, due to the possible nonlinear structures of one's training set, we evolve the pre-image obtained through kernel PCA for the task of shape analysis. Third, we show that the derivation for shape weights is general. This allows us to use various kernels, as well as other statistical learning methodologies, with only minimal changes needing to be made to the overall shape evolution scheme. In contrast with other techniques, we approach the nonrigid problem, which is an infinite-dimensional task, with a finite-dimensional optimization scheme. More importantly, we do not explicitly need to know the interaction between various shapes such as that needed for skeleton models as this is done implicitly through shape learning. We provide experimental results on several challenging pose estimation and segmentation scenarios.

  5. Accuracy and robustness of Kinect pose estimation in the context of coaching of elderly population.

    PubMed

    Obdrzálek, Stepán; Kurillo, Gregorij; Ofli, Ferda; Bajcsy, Ruzena; Seto, Edmund; Jimison, Holly; Pavel, Michael

    2012-01-01

    The Microsoft Kinect camera is becoming increasingly popular in many areas aside from entertainment, including human activity monitoring and rehabilitation. Many people, however, fail to consider the reliability and accuracy of the Kinect human pose estimation when they depend on it as a measuring system. In this paper we compare the Kinect pose estimation (skeletonization) with more established techniques for pose estimation from motion capture data, examining the accuracy of joint localization and robustness of pose estimation with respect to the orientation and occlusions. We have evaluated six physical exercises aimed at coaching of elderly population. Experimental results present pose estimation accuracy rates and corresponding error bounds for the Kinect system.

  6. Numerical analytic continuation: Answers to well-posed questions

    NASA Astrophysics Data System (ADS)

    Goulko, Olga; Mishchenko, Andrey S.; Pollet, Lode; Prokof'ev, Nikolay; Svistunov, Boris

    2017-01-01

    We formulate the problem of numerical analytic continuation in a way that lets us draw meaningful conclusions about the properties of the spectral function based solely on the input data. Apart from ensuring consistency with the input data (within their error bars) and the a priori and a posteriori (conditional) constraints, it is crucial to reliably characterize the accuracy—or even ambiguity—of the output. We explain how these challenges can be met with two approaches: stochastic optimization with consistent constraints and the modified maximum entropy method. We perform illustrative tests for spectra with a double-peak structure, where we critically examine which spectral properties are accessible (second peak position and its spectral weight) and which ones are lost (second peak width/shape). For an important practical example, we apply our protocol to the Fermi polaron problem.

  7. Dips in Enrollment Posing Challenges for Urban Districts

    ERIC Educational Resources Information Center

    Gehring, John

    2005-01-01

    Across the U.S., urban school districts are losing students and shuttering schools. In Detroit, some 35,000 students have left the city schools in less than a decade, and the city will close 34 schools and reassign more than 10,000 students in 2006. However, the trend is not limited to Rust Belt cities like Detroit, although their problems tend to…

  8. Dips in Enrollment Posing Challenges for Urban Districts

    ERIC Educational Resources Information Center

    Gehring, John

    2005-01-01

    Across the U.S., urban school districts are losing students and shuttering schools. In Detroit, some 35,000 students have left the city schools in less than a decade, and the city will close 34 schools and reassign more than 10,000 students in 2006. However, the trend is not limited to Rust Belt cities like Detroit, although their problems tend to…

  9. A multiscale expectation-maximization semisupervised classifier suitable for badly posed image classification.

    PubMed

    Baraldi, Andrea; Bruzzone, Lorenzo; Blonda, Palma

    2006-08-01

    This paper deals with the problem of badly posed image classification. Although underestimated in practice, bad-posedness is likely to affect many real-world image classification tasks, where reference samples are difficult to collect (e.g., in remote sensing (RS) image mapping) and/or spatial autocorrelation is relevant. In an image classification context affected by a lack of reference samples, an original inductive learning multiscale image classifier, termed multiscale semisupervised expectation maximization (MSEM), is proposed. The rationale behind MSEM is to combine useful complementary properties of two alternative data mapping procedures recently published outside of image processing literature, namely, the multiscale modified Pappas adaptive clustering (MPAC) algorithm and the sample-based semisupervised expectation maximization (SEM) classifier. To demonstrate its potential utility, MSEM is compared against nonstandard classifiers, such as MPAC, SEM and the single-scale contextual SEM (CSEM) classifier, besides against well-known standard classifiers in two RS image classification problems featuring few reference samples and modestly useful texture information. These experiments yield weak (subjective) but numerous quantitative map quality indexes that are consistent with both theoretical considerations and qualitative evaluations by expert photointerpreters. According to these quantitative results, MSEM is competitive in terms of overall image mapping performance at the cost of a computational overhead three to six times superior to that of its most interesting rival, SEM. More in general, our experiments confirm that, even if they rely on heavy class-conditional normal distribution assumptions that may not be true in many real-world problems (e.g., in highly textured images), semisupervised classifiers based on the iterative expectation maximization Gaussian mixture model solution can be very powerful in practice when: 1) there is a lack of reference

  10. Pose Versus State: are Sensor Position and Attitude Sufficient for Modern Photogrammetry and Remote Sensing?

    NASA Astrophysics Data System (ADS)

    Colomina, I.; Blázquez, M.

    2014-03-01

    We investigate the advantages of using what we call sensor state parameters or sensor state to describe the geometrical relationship between a sensor and the 3D space or the 4D time-space that extend the traditional image pose or orientation (position and attitude) to the image state. In our concept, at some point in time t, the sensor state is a 12-dimensional vector composed of four 3-dimensional subvectors p(t), v(t), γ(t) and ω(t). Roughly speaking, p(t) is the sensor's position, v(t) its linear velocity, γ(t) its attitude and ω(t) its angular velocity. It is clear that the state concept extends the pose or orientation ones and attempts to describe both a sensor's statics (p(t), γ(t)) and dynamics (v(t), ω(t)). It is also clear that if p(t), γ(t) are known for all t within some time interval of interest, then v(t) and ω(t) can be derived from the former. We present three methods to compute the state parameters, two for the continuous case and one for the discrete case. The first two methods rely on the availability of inertial measurements and their derived time-Position-Velocity-Attitude (tPVA) trajectories. The first method extends the INS mechanization equations and the second method derives the IMU angular velocities from INS mechanization equations' output data. The third method derives lineal and angular velocities from relative orientation parameters. We illustrate how sensor states can be applied to solve practical problems. For this purpose we have selected three cases: multi-sensor synchronization calibration, correction of image motion blur (translational and rotational) and accurate orientation of images acquired with focal-plane shutters.

  11. Posing the questions that science has not asked

    SciTech Connect

    Lane, N.

    1995-12-31

    The author addresses the changing environment for research at American universities as they deal with a swiftly changing world. The next few years are viewed as a transition from traditional approaches to university research. Integration of research and teaching is examined since the approach widely varies among colleges and universities. The research infrastructure is viewed as crumbling or obsolete. The role of the National Science Foundation and its methodology for managing research grants is discussed in detail. The nation has real needs and problems in which our scientific laboratories can provide valuable assistance.

  12. What risks do herbal products pose to the Australian community?

    PubMed

    Byard, Roger W; Musgrave, Ian; Maker, Garth; Bunce, Michael

    2017-02-06

    Traditional herbal products are widely used in Australia to treat a broad range of conditions and diseases. It is popularly believed that these products are safer than prescribed drugs. While many may be safe, it is worrying that the specific effects and harmful interactions of a number of their components with prescription medications is not well understood. Some traditional herbal preparations contain heavy metals and toxic chemicals, as well as naturally occurring organic toxins. The effects of these substances can be dire, including acute hepatic and renal failure, exacerbation of pre-existing conditions and diseases, and even death. The content and quality of herbal preparations are not tightly controlled, with some ingredients either not listed or their concentrations recorded inaccurately on websites or labels. Herbal products may also include illegal ingredients, such as ephedra, Asarum europaeum (European wild ginger) and endangered animal species (eg, snow leopard). An additional problem is augmentation with prescription medications to enhance the apparent effectiveness of a preparation. Toxic substances may also be deliberately or inadvertently added: less expensive, more harmful plants may be substituted for more expensive ingredients, and processing may not be adequate. The lack of regulation and monitoring of traditional herbal preparations in Australia and other Western countries means that their contribution to illness and death is unknown. We need to raise awareness of these problems with health care practitioners and with the general public.

  13. Keyframe selection for robust pose estimation in laparoscopic videos

    NASA Astrophysics Data System (ADS)

    von Öhsen, Udo; Marcinczak, Jan Marek; Mármol Vélez, Andres F.; Grigat, Rolf-Rainer

    2012-02-01

    Motion estimation based on point correspondences in two views is a classic problem in computer vision. In the field of laparoscopic video sequences - even with state of the art algorithms - a stable motion estimation can not be guaranteed generally. Typically, a video from a laparoscopic surgery contains sequences where the surgeon barely moves the endoscope. Such restricted movement causes a small ratio between baseline and distance leading to unstable estimation results. Exploiting the fact that the entire sequence is known a priori, we propose an algorithm for keyframe selection in a sequence of images. The key idea can be expressed as follows: if all combination of frames in a sequence are scored, the optimal solution can be described as a weighted directed graph problem. We adapt the widely known Dijkstras Algorithm to find the best selection of frames.1 The framework for keyframe selection can be used universally to find the best combination of frames for any reliable scoring function. For instance, forward motion ensures the most accurate camera position estimation, whereas sideward motion is preferred in the sense of reconstruction. Based on the distribution and the disparity of point correspondences, we propose a scoring function which is capable of detecting poorly conditioned pairs of frames. We demonstrate the potential of the algorithm focusing on accurate camera positions. A robot system provides ground truth data. The environment in laparoscopic videos is reflected by an industrial endoscope and a phantom.

  14. Concentrations of hemoglobin fractions calculation using modified Lambert-Beer law and solving of an ill-posed system of equations

    NASA Astrophysics Data System (ADS)

    Abdallah, Omar; Natsheh, Mohammed; Abo Alam, Kawther; Qananwah, Qasem; Al Nabulsi, Ahmed; Bolz, Armin

    2010-04-01

    Based on the optical methods, it could be able to identify the concentrations of the hemoglobin fractions in a few seconds. An array of Light Emitting Diodes "LEDs" with different wavelengths and a photo detector were used to detect the transmitted or reflected light intensities. A system of equations was built according to the modified Lambert-Beer Law to be solved as an inverse problem. Typically practical inverse problems are all ill-posed. Even well-posed problems may be unstable or ill-conditioned when they digitalized. Also, applications in tissue spectroscopy and optical imaging result in an ill-posed problems. The difficulties involved in solving ill-posed systems are known, where large changes in the solution result from small perturbations in the right hand members of the system that can be caused by measurement tolerance or noise. A good numerical method to solve it may be beneficial in the applications to the optimization problems including linear programming and nonlinear programming. To account for the sensitivity to noise, a regularization method is usually applied to solve this sort of ill-posed problem, where a suitable regularized parameter is used to depress the bias in the computed solution by a better balance of approximation error and propagated data error. The Method has better computational efficiency and accuracy even for the highly ill-conditioned linear equations with a large disturbance on the given data. Comparing the results with that obtained from a direct solution of the system of equations, we prove well-posedness, stability and convergence of the method. The estimated hemoglobin fractions were highly correlated to the reference laboratory measurements.

  15. Prospective evaluation of shape similarity based pose prediction method in D3R Grand Challenge 2015

    NASA Astrophysics Data System (ADS)

    Kumar, Ashutosh; Zhang, Kam Y. J.

    2016-09-01

    Evaluation of ligand three-dimensional (3D) shape similarity is one of the commonly used approaches to identify ligands similar to one or more known active compounds from a library of small molecules. Apart from using ligand shape similarity as a virtual screening tool, its role in pose prediction and pose scoring has also been reported. We have recently developed a method that utilizes ligand 3D shape similarity with known crystallographic ligands to predict binding poses of query ligands. Here, we report the prospective evaluation of our pose prediction method through the participation in drug design data resource (D3R) Grand Challenge 2015. Our pose prediction method was used to predict binding poses of heat shock protein 90 (HSP90) and mitogen activated protein kinase kinase kinase kinase (MAP4K4) ligands and it was able to predict the pose within 2 Å root mean square deviation (RMSD) either as the top pose or among the best of five poses in a majority of cases. Specifically for HSP90 protein, a median RMSD of 0.73 and 0.68 Å was obtained for the top and the best of five predictions respectively. For MAP4K4 target, although the median RMSD for our top prediction was only 2.87 Å but the median RMSD of 1.67 Å for the best of five predictions was well within the limit for successful prediction. Furthermore, the performance of our pose prediction method for HSP90 and MAP4K4 ligands was always among the top five groups. Particularly, for MAP4K4 protein our pose prediction method was ranked number one both in terms of mean and median RMSD when the best of five predictions were considered. Overall, our D3R Grand Challenge 2015 results demonstrated that ligand 3D shape similarity with the crystal ligand is sufficient to predict binding poses of new ligands with acceptable accuracy.

  16. Estimation of Full-Body Poses Using Only Five Inertial Sensors: An Eager or Lazy Learning Approach?

    PubMed

    Wouda, Frank J; Giuberti, Matteo; Bellusci, Giovanni; Veltink, Peter H

    2016-12-15

    Human movement analysis has become easier with the wide availability of motion capture systems. Inertial sensing has made it possible to capture human motion without external infrastructure, therefore allowing measurements in any environment. As high-quality motion capture data is available in large quantities, this creates possibilities to further simplify hardware setups, by use of data-driven methods to decrease the number of body-worn sensors. In this work, we contribute to this field by analyzing the capabilities of using either artificial neural networks (eager learning) or nearest neighbor search (lazy learning) for such a problem. Sparse orientation features, resulting from sensor fusion of only five inertial measurement units with magnetometers, are mapped to full-body poses. Both eager and lazy learning algorithms are shown to be capable of constructing this mapping. The full-body output poses are visually plausible with an average joint position error of approximately 7 cm, and average joint angle error of 7 ∘ . Additionally, the effects of magnetic disturbances typical in orientation tracking on the estimation of full-body poses was also investigated, where nearest neighbor search showed better performance for such disturbances.

  17. Estimation of Full-Body Poses Using Only Five Inertial Sensors: An Eager or Lazy Learning Approach?

    PubMed Central

    Wouda, Frank J.; Giuberti, Matteo; Bellusci, Giovanni; Veltink, Peter H.

    2016-01-01

    Human movement analysis has become easier with the wide availability of motion capture systems. Inertial sensing has made it possible to capture human motion without external infrastructure, therefore allowing measurements in any environment. As high-quality motion capture data is available in large quantities, this creates possibilities to further simplify hardware setups, by use of data-driven methods to decrease the number of body-worn sensors. In this work, we contribute to this field by analyzing the capabilities of using either artificial neural networks (eager learning) or nearest neighbor search (lazy learning) for such a problem. Sparse orientation features, resulting from sensor fusion of only five inertial measurement units with magnetometers, are mapped to full-body poses. Both eager and lazy learning algorithms are shown to be capable of constructing this mapping. The full-body output poses are visually plausible with an average joint position error of approximately 7 cm, and average joint angle error of 7∘. Additionally, the effects of magnetic disturbances typical in orientation tracking on the estimation of full-body poses was also investigated, where nearest neighbor search showed better performance for such disturbances. PMID:27983676

  18. An ill-posed parabolic evolution system for dispersive deoxygenation-reaeration in water

    NASA Astrophysics Data System (ADS)

    Azaïez, M.; Ben Belgacem, F.; Hecht, F.; Le Bot, C.

    2014-01-01

    We consider an inverse problem that arises in the management of water resources and pertains to the analysis of surface water pollution by organic matter. Most physically relevant models used by engineers derive from various additions and corrections to enhance the earlier deoxygenation-reaeration model proposed by Streeter and Phelps in 1925, the unknowns being the biochemical oxygen demand (BOD) and the dissolved oxygen (DO) concentrations. The one we deal with includes Taylor’s dispersion to account for the heterogeneity of the contamination in all space directions. The system we obtain is then composed of two reaction-dispersion equations. The particularity is that both Neumann and Dirichlet boundary conditions are available on the DO tracer while the BOD density is free of any conditions. In fact, for real-life concerns, measurements on the DO are easy to obtain and to save. On the contrary, collecting data on the BOD is a sensitive task and turns out to be a lengthy process. The global model pursues the reconstruction of the BOD density, and especially of its flux along the boundary. Not only is this problem plainly worth studying for its own interest but it could also be a mandatory step in other applications such as the identification of the location of pollution sources. The non-standard boundary conditions generate two difficulties in mathematical and computational grounds. They set up a severe coupling between both equations and they are the cause of the ill-posed data reconstruction problem. Existence and stability fail. Identifiability is therefore the only positive result one can search for; it is the central purpose of the paper. Finally, we have performed some computational experiments to assess the capability of the mixed finite element in missing data recovery.

  19. Real-time human pose detection and tracking for tele-rehabilitation in virtual reality.

    PubMed

    Obdržálek, Stěpán; Kurillo, Gregorij; Han, Jay; Abresch, Ted; Bajcsy, Ruzena

    2012-01-01

    We present a real-time algorithm for human pose detection and tracking from vision-based 3D data and its application to tele-rehabilitation in virtual environments. We employ stereo camera(s) to capture 3D avatars of geographically dislocated patient and therapist in real-time, while sending the data remotely and displaying it in a virtual scene. A pose detection and tracking algorithm extracts kinematic parameters from each participant and determines pose similarity. The pose similarity score is used to quantify patient's performance and provide real-time feedback for remote rehabilitation.

  20. On Problems with Solutions Attainable in More Than One Way.

    ERIC Educational Resources Information Center

    Pedersen, Jean; Polya, George

    1984-01-01

    Presents three sample problems related to arithmetic and algebra, geometry, and calculus, indicating, in each case, similar problems that could be posed. Includes a discussion of positive benefits which result by asking students "Can you derive the result differently?" (JN)

  1. About well-posed definition of geophysical fields'

    NASA Astrophysics Data System (ADS)

    Ermokhine, Konstantin; Zhdanova, Ludmila; Litvinova, Tamara

    2013-04-01

    We introduce a new approach to the downward continuation of geophysical fields based on approximation of observed data by continued fractions. Key Words: downward continuation, continued fraction, Viskovatov's algorithm. Many papers in geophysics are devoted to the downward continuation of geophysical fields from the earth surface to the lower halfspace. Known obstacle for the method practical use is a field's breaking-down phenomenon near the pole closest to the earth surface. It is explained by the discrepancy of the studied fields' mathematical description: linear presentation of the field in the polynomial form, Taylor or Fourier series, leads to essential and unremovable instability of the inverse problem since the field with specific features in the form of poles in the lower halfspace principally can't be adequately described by the linear construction. Field description by the rational fractions is closer to reality. In this case the presence of function's poles in the lower halfspace corresponds adequately to the denominator zeros. Method proposed below is based on the continued fractions. Let's consider the function measured along the profile and represented it in the form of the Tchebishev series (preliminary reducing the argument to the interval [-1, 1]): There are many variants of power series' presentation by continued fractions. The areas of series and corresponding continued fraction's convergence may differ essentially. As investigations have shown, the most suitable mathematical construction for geophysical fields' continuation is so called general C-fraction: where ( , z designates the depth) For construction of C-fraction corresponding to power series exists a rather effective and stable Viskovatov's algorithm (Viskovatov B. "De la methode generale pour reduire toutes sortes des quantitees en fraction continues". Memoires de l' Academie Imperiale des Sciences de St. Petersburg, 1, 1805). A fundamentally new algorithm for Downward Continuation

  2. Research Mathematicians' Practices in Selecting Mathematical Problems

    ERIC Educational Resources Information Center

    Misfeldt, Morten; Johansen, Mikkel Willum

    2015-01-01

    Developing abilities to create, inquire into, qualify, and choose among mathematical problems is an important educational goal. In this paper, we elucidate how mathematicians work with mathematical problems in order to understand this mathematical process. More specifically, we investigate how mathematicians select and pose problems and discuss to…

  3. The Coffee-Milk Mixture Problem Revisited

    ERIC Educational Resources Information Center

    Marion, Charles F.

    2015-01-01

    This analysis of a problem that is frequently posed at professional development workshops, in print, and on the Web--the coffee-milk mixture riddle--illustrates the timeless advice of George Pólya's masterpiece on problem solving in mathematics, "How to Solve It." In his book, Pólya recommends that problems previously solved and put…

  4. The Coffee-Milk Mixture Problem Revisited

    ERIC Educational Resources Information Center

    Marion, Charles F.

    2015-01-01

    This analysis of a problem that is frequently posed at professional development workshops, in print, and on the Web--the coffee-milk mixture riddle--illustrates the timeless advice of George Pólya's masterpiece on problem solving in mathematics, "How to Solve It." In his book, Pólya recommends that problems previously solved and put…

  5. Research Mathematicians' Practices in Selecting Mathematical Problems

    ERIC Educational Resources Information Center

    Misfeldt, Morten; Johansen, Mikkel Willum

    2015-01-01

    Developing abilities to create, inquire into, qualify, and choose among mathematical problems is an important educational goal. In this paper, we elucidate how mathematicians work with mathematical problems in order to understand this mathematical process. More specifically, we investigate how mathematicians select and pose problems and discuss to…

  6. Weak evidence on nalmefene creates dilemmas for clinicians and poses questions for regulators and researchers

    PubMed Central

    Angus, Kathryn; Elders, Andrew; de Andrade, Marisa; Raistrick, Duncan; Heather, Nick; McCambridge, Jim

    2016-01-01

    Abstract Background and aims Nalmefene has been approved in Europe for the treatment of alcohol dependence and subsequently recommended by the UK National Institute for Health and Care Excellence (NICE). This study examines critically the evidence base underpinning both decisions and the issues arising. Methods Published studies of nalmefene were identified through a systematic search, with documents from the European Medicines Agency, the NICE appraisal and public clinical trial registries also examined to identify methodological issues. Results Efficacy data used to support the licensing of nalmefene suffer from risk of bias due to lack of specification of a priori outcome measures and sensitivity analyses, use of post‐hoc sample refinement and the use of inappropriate comparators. Despite this, evidence for the efficacy of nalmefene in reducing alcohol consumption in those with alcohol dependence is, at best, modest, and of uncertain significance to individual patients. The relevance of existing trial data to routine primary care practice is doubtful. Conclusions Problems with the registration, design, analysis and reporting of clinical trials of nalmefene did not prevent it being licensed and recommended for treating alcohol dependence. This creates dilemmas for primary care clinicians and commissioning organisations where nalmefene has been heavily promoted, and poses wider questions about the effectiveness of the medicines regulation system and how to develop the alcohol treatment evidence base. PMID:27262594

  7. Protein-protein structure prediction by scoring molecular dynamics trajectories of putative poses.

    PubMed

    Sarti, Edoardo; Gladich, Ivan; Zamuner, Stefano; Correia, Bruno E; Laio, Alessandro

    2016-09-01

    The prediction of protein-protein interactions and their structural configuration remains a largely unsolved problem. Most of the algorithms aimed at finding the native conformation of a protein complex starting from the structure of its monomers are based on searching the structure corresponding to the global minimum of a suitable scoring function. However, protein complexes are often highly flexible, with mobile side chains and transient contacts due to thermal fluctuations. Flexibility can be neglected if one aims at finding quickly the approximate structure of the native complex, but may play a role in structure refinement, and in discriminating solutions characterized by similar scores. We here benchmark the capability of some state-of-the-art scoring functions (BACH-SixthSense, PIE/PISA and Rosetta) in discriminating finite-temperature ensembles of structures corresponding to the native state and to non-native configurations. We produce the ensembles by running thousands of molecular dynamics simulations in explicit solvent starting from poses generated by rigid docking and optimized in vacuum. We find that while Rosetta outperformed the other two scoring functions in scoring the structures in vacuum, BACH-SixthSense and PIE/PISA perform better in distinguishing near-native ensembles of structures generated by molecular dynamics in explicit solvent. Proteins 2016; 84:1312-1320. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  8. The Spatial and the Visual in Mental Spatial Reasoning: An Ill-Posed Distinction

    NASA Astrophysics Data System (ADS)

    Schultheis, Holger; Bertel, Sven; Barkowsky, Thomas; Seifert, Inessa

    It is an ongoing and controversial debate in cognitive science which aspects of knowledge humans process visually and which ones they process spatially. Similarly, artificial intelligence (AI) and cognitive science research, in building computational cognitive systems, tended to use strictly spatial or strictly visual representations. The resulting systems, however, were suboptimal both with respect to computational efficiency and cognitive plau sibility. In this paper, we propose that the problems in both research strands stem from a mis conception of the visual and the spatial in mental spatial knowl edge pro cessing. Instead of viewing the visual and the spatial as two clearly separable categories, they should be conceptualized as the extremes of a con tinuous dimension of representation. Regarding psychology, a continuous di mension avoids the need to exclusively assign processes and representations to either one of the cate gories and, thus, facilitates a more unambiguous rating of processes and rep resentations. Regarding AI and cognitive science, the con cept of a continuous spatial / visual dimension provides the possibility of rep re sentation structures which can vary continuously along the spatial / visual di mension. As a first step in exploiting these potential advantages of the pro posed conception we (a) introduce criteria allowing for a non-dichotomic judgment of processes and representations and (b) present an approach towards rep re sentation structures that can flexibly vary along the spatial / visual dimension.

  9. Application of structured support vector machine backpropagation to a convolutional neural network for human pose estimation.

    PubMed

    Witoonchart, Peerajak; Chongstitvatana, Prabhas

    2017-08-01

    In this study, for the first time, we show how to formulate a structured support vector machine (SSVM) as two layers in a convolutional neural network, where the top layer is a loss augmented inference layer and the bottom layer is the normal convolutional layer. We show that a deformable part model can be learned with the proposed structured SVM neural network by backpropagating the error of the deformable part model to the convolutional neural network. The forward propagation calculates the loss augmented inference and the backpropagation calculates the gradient from the loss augmented inference layer to the convolutional layer. Thus, we obtain a new type of convolutional neural network called an Structured SVM convolutional neural network, which we applied to the human pose estimation problem. This new neural network can be used as the final layers in deep learning. Our method jointly learns the structural model parameters and the appearance model parameters. We implemented our method as a new layer in the existing Caffe library. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. 42 CFR 493.1812 - Action when deficiencies pose immediate jeopardy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... the laboratory, regardless of the type of CLIA certificate the laboratory has and of whether it is... AND HUMAN SERVICES (CONTINUED) STANDARDS AND CERTIFICATION LABORATORY REQUIREMENTS Enforcement Procedures § 493.1812 Action when deficiencies pose immediate jeopardy. If a laboratory's deficiencies pose...

  11. 21 CFR 740.18 - Coal tar hair dyes posing a risk of cancer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 7 2014-04-01 2014-04-01 false Coal tar hair dyes posing a risk of cancer. 740.18... posing a risk of cancer. (a) The principal display panel of the label and any labeling accompanying a... your skin and has been determined to cause cancer in laboratory animals. (b) Hair dyes containing any...

  12. 21 CFR 740.18 - Coal tar hair dyes posing a risk of cancer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 7 2013-04-01 2013-04-01 false Coal tar hair dyes posing a risk of cancer. 740.18... posing a risk of cancer. (a) The principal display panel of the label and any labeling accompanying a... your skin and has been determined to cause cancer in laboratory animals. (b) Hair dyes containing any...

  13. 21 CFR 740.18 - Coal tar hair dyes posing a risk of cancer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 7 2011-04-01 2010-04-01 true Coal tar hair dyes posing a risk of cancer. 740.18... posing a risk of cancer. (a) The principal display panel of the label and any labeling accompanying a... your skin and has been determined to cause cancer in laboratory animals. (b) Hair dyes containing any...

  14. 21 CFR 740.18 - Coal tar hair dyes posing a risk of cancer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 7 2012-04-01 2012-04-01 false Coal tar hair dyes posing a risk of cancer. 740.18... posing a risk of cancer. (a) The principal display panel of the label and any labeling accompanying a... your skin and has been determined to cause cancer in laboratory animals. (b) Hair dyes containing any...

  15. 21 CFR 740.18 - Coal tar hair dyes posing a risk of cancer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Coal tar hair dyes posing a risk of cancer. 740.18... posing a risk of cancer. (a) The principal display panel of the label and any labeling accompanying a... your skin and has been determined to cause cancer in laboratory animals. (b) Hair dyes containing any...

  16. Metacognition in Chemical Education: Question Posing in the Case-Based Computerized Learning Environment

    ERIC Educational Resources Information Center

    Kaberman, Zvia; Dori, Yehudit Judy

    2009-01-01

    Posing questions about an article might improve one's knowledge--a cognitive function, or monitor one's thought processes--a metacognitive function. This study focuses on guided question posing while using a metacognitive strategy by 12th grade honors chemistry students. We investigated the ways by which the metacognitive strategy affected…

  17. Question-Posing Capability as an Alternative Evaluation Method: Analysis of an Environmental Case Study.

    ERIC Educational Resources Information Center

    Dori, Yehudit J.; Herscovitz, Orit

    1999-01-01

    Presents research on the scientific question-posing capabilities of 10th-grade students (n=127) who were studying air quality in a cooperative way using the jigsaw method. Finds that the difference between students at high and low academic levels to the extent of increase in both number and complexity of posed questions was significant. Contains…

  18. Metacognition in Chemical Education: Question Posing in the Case-Based Computerized Learning Environment

    ERIC Educational Resources Information Center

    Kaberman, Zvia; Dori, Yehudit Judy

    2009-01-01

    Posing questions about an article might improve one's knowledge--a cognitive function, or monitor one's thought processes--a metacognitive function. This study focuses on guided question posing while using a metacognitive strategy by 12th grade honors chemistry students. We investigated the ways by which the metacognitive strategy affected…

  19. Tooth display and lip position during spontaneous and posed smiling in adults.

    PubMed

    Van Der Geld, Pieter; Oosterveld, Paul; Berge, Stefaan J; Kuijpers-Jagtman, Anne M

    2008-08-01

    To analyze differences in tooth display, lip-line height, and smile width between the posed smiling record, traditionally produced for orthodontic diagnosis, and the spontaneous (Duchenne) smile of joy. The faces of 122 male participants were each filmed during spontaneous and posed smiling. Spontaneous smiles were elicited through the participants watching a comical movie. Maxillary and mandibular lip-line heights, tooth display, and smile width were measured using a digital videographic method for smile analysis. Paired sample t-tests were used to compare measurements of posed and spontaneous smiling. Maxillary lip-line heights during spontaneous smiling were significantly higher than during posed smiling. Compared to spontaneous smiling, tooth display in the (pre)molar area during posed smiling decreased by up to 30%, along with a significant reduction of smile width. During posed smiling, also mandibular lip-line heights changed and the teeth were more covered by the lower lip than during spontaneous smiling. Reduced lip-line heights, tooth display, and smile width on a posed smiling record can have implications for the diagnostics of lip-line height, smile arc, buccal corridors, and plane of occlusion. Spontaneous smiling records next to posed smiling records are therefore recommended for diagnostic purposes. Because of the dynamic nature of spontaneous smiling, it is proposed to switch to dynamic video recording of the smile.

  20. Improving docking results via reranking of ensembles of ligand poses in multiple X-ray protein conformations with MM-GBSA.

    PubMed

    Greenidge, P A; Kramer, C; Mozziconacci, J-C; Sherman, W

    2014-10-27

    There is a tendency in the literature to be critical of scoring functions when docking programs perform poorly. The assumption is that existing scoring functions need to be enhanced or new ones developed in order to improve the performance of docking programs for tasks such as pose prediction and virtual screening. However, failures can result from either sampling or scoring (or a combination of the two), although less emphasis tends to be given to the former. In this work, we use the programs GOLD and Glide on a high-quality data set to explore whether failures in pose prediction and binding affinity estimation can be attributable more to sampling or scoring. We show that identification of the correct pose (docking power) can be improved by incorporating ligand strain into the scoring function or rescoring an ensemble of diverse docking poses with MM-GBSA in a postprocessing step. We explore the use of nondefault docking settings and find that enhancing ligand sampling also improves docking power, again suggesting that sampling is more limiting than scoring for the docking programs investigated in this work. In cross-docking calculations (docking a ligand to a noncognate receptor structure) we observe a significant reduction in the accuracy of pose ranking, as expected and has been reported by others; however, we demonstrate that these alternate poses may in fact be more complementary between the ligand and the rigid receptor conformation, emphasizing that treating the receptor rigidly is an artificial constraint on the docking problem. We simulate protein flexibility by the use of multiple crystallographic conformations of a protein and demonstrate that docking results can be improved with this level of protein sampling. This work indicates the need for better sampling in docking programs, especially for the receptor. This study also highlights the variable descriptive value of RMSD as the sole arbiter of pose replication quality. It is shown that ligand poses

  1. Globally Convergent Numerical Methods for Coefficient Inverse Problems

    DTIC Science & Technology

    2008-09-23

    Problems , 18, 209-219, 2002. 50. A.N. Tikhonov and V. Ya. Arsenin , Solutions of Ill - Posed Problems Winston & Sons. Washington...is because solutions of PDEs depend nonlinearly on their coefficients. The ill - posedness is a well known feature of inverse problems . This means that...ut (x, 0)‖L2(Ω) ≤ CK. Theorem 8.5 enables us to prove convergence of our method. Following the Tikhonov concept for ill - posed problems [50], we

  2. Foot Pose Estimation Using an Inertial Sensor Unit and Two Distance Sensors.

    PubMed

    Duong, Pham Duy; Suh, Young Soo

    2015-07-03

    There are many inertial sensor-based foot pose estimation algorithms. In this paper, we present a methodology to improve the accuracy of foot pose estimation using two low-cost distance sensors (VL6180) in addition to an inertial sensor unit. The distance sensor is a time-of-flight range finder and can measure distance up to 20 cm. A Kalman filter with 21 states is proposed to estimate both the calibration parameter (relative pose of distance sensors with respect to the inertial sensor unit) and foot pose. Once the calibration parameter is obtained, a Kalman filter with nine states can be used to estimate foot pose. Through four activities (walking, dancing step, ball kicking, jumping), it is shown that the proposed algorithm significantly improves the vertical position estimation.

  3. Foot Pose Estimation Using an Inertial Sensor Unit and Two Distance Sensors

    PubMed Central

    Duong, Pham Duy; Suh, Young Soo

    2015-01-01

    There are many inertial sensor-based foot pose estimation algorithms. In this paper, we present a methodology to improve the accuracy of foot pose estimation using two low-cost distance sensors (VL6180) in addition to an inertial sensor unit. The distance sensor is a time-of-flight range finder and can measure distance up to 20 cm. A Kalman filter with 21 states is proposed to estimate both the calibration parameter (relative pose of distance sensors with respect to the inertial sensor unit) and foot pose. Once the calibration parameter is obtained, a Kalman filter with nine states can be used to estimate foot pose. Through four activities (walking, dancing step, ball kicking, jumping), it is shown that the proposed algorithm significantly improves the vertical position estimation. PMID:26151205

  4. Head Pose Estimation Using Multilinear Subspace Analysis for Robot Human Awareness

    NASA Technical Reports Server (NTRS)

    Ivanov, Tonislav; Matthies, Larry; Vasilescu, M. Alex O.

    2009-01-01

    Mobile robots, operating in unconstrained indoor and outdoor environments, would benefit in many ways from perception of the human awareness around them. Knowledge of people's head pose and gaze directions would enable the robot to deduce which people are aware of the its presence, and to predict future motions of the people for better path planning. To make such inferences, requires estimating head pose on facial images that are combination of multiple varying factors, such as identity, appearance, head pose, and illumination. By applying multilinear algebra, the algebra of higher-order tensors, we can separate these factors and estimate head pose regardless of subject's identity or image conditions. Furthermore, we can automatically handle uncertainty in the size of the face and its location. We demonstrate a pipeline of on-the-move detection of pedestrians with a robot stereo vision system, segmentation of the head, and head pose estimation in cluttered urban street scenes.

  5. Head Pose Estimation Using Multilinear Subspace Analysis for Robot Human Awareness

    NASA Technical Reports Server (NTRS)

    Ivanov, Tonislav; Matthies, Larry; Vasilescu, M. Alex O.

    2009-01-01

    Mobile robots, operating in unconstrained indoor and outdoor environments, would benefit in many ways from perception of the human awareness around them. Knowledge of people's head pose and gaze directions would enable the robot to deduce which people are aware of the its presence, and to predict future motions of the people for better path planning. To make such inferences, requires estimating head pose on facial images that are combination of multiple varying factors, such as identity, appearance, head pose, and illumination. By applying multilinear algebra, the algebra of higher-order tensors, we can separate these factors and estimate head pose regardless of subject's identity or image conditions. Furthermore, we can automatically handle uncertainty in the size of the face and its location. We demonstrate a pipeline of on-the-move detection of pedestrians with a robot stereo vision system, segmentation of the head, and head pose estimation in cluttered urban street scenes.

  6. Stereovision-based pose and inertia estimation of unknown and uncooperative space objects

    NASA Astrophysics Data System (ADS)

    Pesce, Vincenzo; Lavagna, Michèle; Bevilacqua, Riccardo

    2017-01-01

    Autonomous close proximity operations are an arduous and attractive problem in space mission design. In particular, the estimation of pose, motion and inertia properties of an uncooperative object is a challenging task because of the lack of available a priori information. This paper develops a novel method to estimate the relative position, velocity, angular velocity, attitude and the ratios of the components of the inertia matrix of an uncooperative space object using only stereo-vision measurements. The classical Extended Kalman Filter (EKF) and an Iterated Extended Kalman Filter (IEKF) are used and compared for the estimation procedure. In addition, in order to compute the inertia properties, the ratios of the inertia components are added to the state and a pseudo-measurement equation is considered in the observation model. The relative simplicity of the proposed algorithm could be suitable for an online implementation for real applications. The developed algorithm is validated by numerical simulations in MATLAB using different initial conditions and uncertainty levels. The goal of the simulations is to verify the accuracy and robustness of the proposed estimation algorithm. The obtained results show satisfactory convergence of estimation errors for all the considered quantities. The obtained results, in several simulations, shows some improvements with respect to similar works, which deal with the same problem, present in literature. In addition, a video processing procedure is presented to reconstruct the geometrical properties of a body using cameras. This inertia reconstruction algorithm has been experimentally validated at the ADAMUS (ADvanced Autonomous MUltiple Spacecraft) Lab at the University of Florida. In the future, this different method could be integrated to the inertia ratios estimator to have a complete tool for mass properties recognition.

  7. Robust 3D object localization and pose estimation for random bin picking with the 3DMaMa algorithm

    NASA Astrophysics Data System (ADS)

    Skotheim, Øystein; Thielemann, Jens T.; Berge, Asbjørn; Sommerfelt, Arne

    2010-02-01

    Enabling robots to automatically locate and pick up randomly placed and oriented objects from a bin is an important challenge in factory automation, replacing tedious and heavy manual labor. A system should be able to recognize and locate objects with a predefined shape and estimate the position with the precision necessary for a gripping robot to pick it up. We describe a system that consists of a structured light instrument for capturing 3D data and a robust approach for object location and pose estimation. The method does not depend on segmentation of range images, but instead searches through pairs of 2D manifolds to localize candidates for object match. This leads to an algorithm that is not very sensitive to scene complexity or the number of objects in the scene. Furthermore, the strategy for candidate search is easily reconfigurable to arbitrary objects. Experiments reported in this paper show the utility of the method on a general random bin picking problem, in this paper exemplified by localization of car parts with random position and orientation. Full pose estimation is done in less than 380 ms per image. We believe that the method is applicable for a wide range of industrial automation problems where precise localization of 3D objects in a scene is needed.

  8. Using Facial Symmetry to Handle Pose Variations in Real-World 3D Face Recognition.

    PubMed

    Passalis, Georgios; Perakis, Panagiotis; Theoharis, Theoharis; Kakadiaris, Ioannis A

    2011-10-01

    The uncontrolled conditions of real-world biometric applications pose a great challenge to any face recognition approach. The unconstrained acquisition of data from uncooperative subjects may result in facial scans with significant pose variations along the yaw axis. Such pose variations can cause extensive occlusions, resulting in missing data. In this paper, a novel 3D face recognition method is proposed that uses facial symmetry to handle pose variations. It employs an automatic landmark detector that estimates pose and detects occluded areas for each facial scan. Subsequently, an Annotated Face Model is registered and fitted to the scan. During fitting, facial symmetry is used to overcome the challenges of missing data. The result is a pose invariant geometry image. Unlike existing methods that require frontal scans, the proposed method performs comparisons among interpose scans using a wavelet-based biometric signature. It is suitable for real-world applications as it only requires half of the face to be visible to the sensor. The proposed method was evaluated using databases from the University of Notre Dame and the University of Houston that, to the best of our knowledge, include the most challenging pose variations publicly available. The average rank-one recognition rate of the proposed method in these databases was 83.7 percent.

  9. Monocular-Based 6-Degree of Freedom Pose Estimation Technology for Robotic Intelligent Grasping Systems

    PubMed Central

    Liu, Tao; Guo, Yin; Yang, Shourui; Yin, Shibin; Zhu, Jigui

    2017-01-01

    Industrial robots are expected to undertake ever more advanced tasks in the modern manufacturing industry, such as intelligent grasping, in which robots should be capable of recognizing the position and orientation of a part before grasping it. In this paper, a monocular-based 6-degree of freedom (DOF) pose estimation technology to enable robots to grasp large-size parts at informal poses is proposed. A camera was mounted on the robot end-flange and oriented to measure several featured points on the part before the robot moved to grasp it. In order to estimate the part pose, a nonlinear optimization model based on the camera object space collinearity error in different poses is established, and the initial iteration value is estimated with the differential transformation. Measuring poses of the camera are optimized based on uncertainty analysis. Also, the principle of the robotic intelligent grasping system was developed, with which the robot could adjust its pose to grasp the part. In experimental tests, the part poses estimated with the method described in this paper were compared with those produced by a laser tracker, and results show the RMS angle and position error are about 0.0228° and 0.4603 mm. Robotic intelligent grasping tests were also successfully performed in the experiments. PMID:28216555

  10. Monocular-Based 6-Degree of Freedom Pose Estimation Technology for Robotic Intelligent Grasping Systems.

    PubMed

    Liu, Tao; Guo, Yin; Yang, Shourui; Yin, Shibin; Zhu, Jigui

    2017-02-14

    Industrial robots are expected to undertake ever more advanced tasks in the modern manufacturing industry, such as intelligent grasping, in which robots should be capable of recognizing the position and orientation of a part before grasping it. In this paper, a monocular-based 6-degree of freedom (DOF) pose estimation technology to enable robots to grasp large-size parts at informal poses is proposed. A camera was mounted on the robot end-flange and oriented to measure several featured points on the part before the robot moved to grasp it. In order to estimate the part pose, a nonlinear optimization model based on the camera object space collinearity error in different poses is established, and the initial iteration value is estimated with the differential transformation. Measuring poses of the camera are optimized based on uncertainty analysis. Also, the principle of the robotic intelligent grasping system was developed, with which the robot could adjust its pose to grasp the part. In experimental tests, the part poses estimated with the method described in this paper were compared with those produced by a laser tracker, and results show the RMS angle and position error are about 0.0228° and 0.4603 mm. Robotic intelligent grasping tests were also successfully performed in the experiments.

  11. Fine-grained bird recognition by using contour-based pose transfer

    NASA Astrophysics Data System (ADS)

    Zhu, Leqing; Lv, Yaoyao; Zhang, Daxing; Zhou, Yadong; Yan, Guoli; Wang, Huiyan; Wang, Xun

    2015-10-01

    We propose a pose transfer method for fine-grained classifications of birds that have wide variations in appearance due to different poses and subcategories. Specifically, bird pose is transferred by using Radon-transform-based contour descriptor, k-means clustering, and K nearest neighbors (KNN) classifier. During training, we clustered annotated image samples into certain poses based on their normalized part locations and used the cluster centers as their consistent part constellations for a particular pose. At the testing stage, Radon-transform-based contour descriptor is used to find the pose a sample belongs to with a KNN classifier by using cosine similarity, and normalized part constellations are transferred to the unannotated image according to the pose type. Bag-of-visual words with OpponentSIFT and color names extracted from each part and from the global image are concatenated as feature vector, which is input to support vector machine for classification. Experimental results demonstrate significant performance gains from our method on the Caltech-UCSD Birds-2011 dataset for the fine-grained bird classification task.

  12. Attribute And-Or Grammar for Joint Parsing of Human Pose, Parts and Attributes.

    PubMed

    Park, Seyoung; Nie, Xiaohan; Zhu, Song-Chun

    2017-07-25

    This paper presents an attribute and-or grammar (A-AOG) model for jointly inferring human body pose and human attributes in a parse graph with attributes augmented to nodes in the hierarchical representation. In contrast to other popular methods in the current literature that train separate classifiers for poses and individual attributes, our method explicitly represents the decomposition and articulation of body parts, and account for the correlations between poses and attributes. The A-AOG model is an amalgamation of three traditional grammar formulations: (i)Phrase structure grammar representing the hierarchical decomposition of the human body from whole to parts; (ii)Dependency grammar modeling the geometric articulation by a kinematic graph of the body pose; and (iii)Attribute grammar accounting for the compatibility relations between different parts in the hierarchy so that their appearances follow a consistent style. The parse graph outputs human detection, pose estimation, and attribute prediction simultaneously, which are intuitive and interpretable. We conduct experiments on two tasks on two datasets, and experimental results demonstrate the advantage of joint modeling in comparison with computing poses and attributes independently. Furthermore, our model obtains better performance over existing methods for both pose estimation and attribute prediction tasks.

  13. Can Holo NMR Chemical Shifts be Directly Used to Resolve RNA-Ligand Poses?

    PubMed

    Frank, Aaron T

    2016-02-22

    Using a set of machine learning based predictors that are capable of predicting ligand-induced shielding effects on (1)H and (13)C nonexchangeable nuclei, it was discovered that holo NMR chemical shifts can be used to resolve RNA-ligand poses. This was accomplished by quantitatively comparing measured and predicted holo chemical shifts in conformationally diverse "decoy" pools for three test cases and then, for each, comparing the native pose to the pose in the decoy pool that exhibited the lowest error. For three test cases, the poses in the decoy pools that exhibited the best agreement between measured and predicted holo chemical shifts were within 0.28, 1.12, and 2.38 Å of the native poses. Interestingly, the predictors used in this study were trained on a database containing, only, apo RNA data. The agreement between the chemical shift-selected poses and the native NMR poses suggests that the predictors used in this study were able to "learn" general chemical shift-structure relationships from apo RNA data that could be used to account for ligand-induced shielding effects on RNA nuclei for the test cases studied.

  14. Bradykinesia of posed smiling and voluntary movement of the lower face in Parkinson's disease.

    PubMed

    Marsili, Luca; Agostino, Rocco; Bologna, Matteo; Belvisi, Daniele; Palma, Adalgisa; Fabbrini, Giovanni; Berardelli, Alfredo

    2014-04-01

    Impaired facial expression, including spontaneous and emotional movements such as smiling, has been often reported in Parkinson's disease (PD). There is a general consensus that spontaneous smiling is abnormal in PD. Investigations on posed smiling yield contrasting results. Moreover, no study has yet addressed the relationship between posed smiling and abnormalities of voluntary movements of the lower face, global motor impairment and the effects of dopaminergic medication. We investigated the kinematics of posed smiling (mimicking a smile shown in a picture) and those of voluntary movements of the lower face (showing the teeth as fast as possible - voluntary grinning) in 15 patients with PD (ON and OFF therapy) and in 16 healthy controls. Facial movements were recorded using a 3D optoelectronic system and analyzed using dedicated software. Some kinematic parameters of both posed smiling and voluntary grinning were abnormally lower in PD patients in comparison to healthy subjects. The kinematics of posed smiling correlated with those of voluntary grinning in PD patients but not in healthy controls. Posed smiling and voluntary grinning abnormalities were related to global motor severity but did not significantly improve upon L-dopa administration. These results suggest that posed smiling and voluntary grinning are both abnormal in PD patients and that they are likely mediated by a common pathophysiological mechanism. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Pose estimation quality assessment for intra-operative image guidance systems

    NASA Astrophysics Data System (ADS)

    Egli, Adrian; Kleinszig, Gerhard; John, Adrian; Fernandez, Alberto; Cardelino, Juan

    2013-03-01

    In trauma and orthopedic surgery screw assessment and trajectory prediction using two-dimensional X-ray images is very difficult due to projected 3D information. However screw assessment can be done with multiple X-ray images. If the X-ray image contains the projected implant geometry it can be used as global coordinate reference. Thereby multiple independent X-ray images can be synchronized by estimating the implant pose in each single image. Consequently high accuracy pose estimation is fundamental. To measure the outcome quality an evaluation process has been designed. The evaluation process investigates in its first step several clinical intra-operative anterior-posterior (AP) and medio-lateral (ML) X-ray images which have been analyzed using a manual pose estimation method. With the manual method the six 3D parameters of the implant pose are estimated. These parameters define as well the camera pose relative to the implant. Based on the pose parameters of all clinical cases the capturing range for typical AP and ML images is statistically defined. The implant was attached to a phantom with 16 steel balls which allows to calculate the ground truth pose. Afterwards several X-ray images of the phantom are taken within the statistically defined capturing range. With the known ground truth different pose estimation methods can be compared. For each method the estimation quality can be calculated. In addition this error calculation can be used to adjust the initial manually determined capturing range. This paper explains the error evaluation process and describes how to validate pose estimation methods for clinical applications.

  16. Head Pose Estimation on Eyeglasses Using Line Detection and Classification Approach

    NASA Astrophysics Data System (ADS)

    Setthawong, Pisal; Vannija, Vajirasak

    This paper proposes a unique approach for head pose estimation of subjects with eyeglasses by using a combination of line detection and classification approaches. Head pose estimation is considered as an important non-verbal form of communication and could also be used in the area of Human-Computer Interface. A major improvement of the proposed approach is that it allows estimation of head poses at a high yaw/pitch angle when compared with existing geometric approaches, does not require expensive data preparation and training, and is generally fast when compared with other approaches.

  17. The silent social/emotional signals in left and right cheek poses: a literature review.

    PubMed

    Lindell, Annukka K

    2013-01-01

    When posing for a painted or photographic portrait, people are more likely to offer their left, rather than right, cheek (e.g., the Mona Lisa). Why? This paper reviews research investigating the left cheek bias, and the reasons underlying this posing asymmetry. Ruling out mechanical and perceptual biases, the paper focuses on the silent emotional and social signals conveyed by left and right cheek poses, demonstrating that people intuitively offer the left cheek to express emotion and perceive left cheek poses as more emotional. Moreover, because the left cheek appears more emotionally expressive, we unconsciously use cheek shown as a cue when presenting or determining academic specialisation, scientific standing, and even political affiliation. The research is consistent in suggesting that something as subtle as a 15° head turn implicitly influences others' perceptions: if you want to be perceived as open and creative, rather than dry and scientific, it might be time to turn the other cheek.

  18. Foale poses with Christmas tree and stockings in the SM galley during Expedition 8

    NASA Image and Video Library

    2003-12-28

    ISS008-E-10754 (28 December 2003) --- Astronaut C. Michael Foale, Expedition 8 mission commander and NASA ISS science officer, poses with holiday decorations in the Zvezda Service Module on the International Space Station (ISS).

  19. Well-posed continuum equations for granular flow with compressibility and μ(I)-rheology

    NASA Astrophysics Data System (ADS)

    Barker, T.; Schaeffer, D. G.; Shearer, M.; Gray, J. M. N. T.

    2017-05-01

    Continuum modelling of granular flow has been plagued with the issue of ill-posed dynamic equations for a long time. Equations for incompressible, two-dimensional flow based on the Coulomb friction law are ill-posed regardless of the deformation, whereas the rate-dependent μ(I)-rheology is ill-posed when the non-dimensional inertial number I is too high or too low. Here, incorporating ideas from critical-state soil mechanics, we derive conditions for well-posedness of partial differential equations that combine compressibility with I-dependent rheology. When the I-dependence comes from a specific friction coefficient μ(I), our results show that, with compressibility, the equations are well-posed for all deformation rates provided that μ(I) satisfies certain minimal, physically natural, inequalities.

  20. POSE: Prediction-Based Opportunistic Sensing for Energy Efficiency in Sensor Networks Using Distributed Supervisors.

    PubMed

    Hare, James Z; Gupta, Shalabh; Wettergren, Thomas A

    2017-08-11

    This paper presents a distributed supervisory control algorithm that enables opportunistic sensing for energy-efficient target tracking in a sensor network. The algorithm called Prediction-based Opportunistic Sensing (POSE), is a distributed node-level energy management approach for minimizing energy usage. Distributed sensor nodes in the POSE network self-adapt to target trajectories by enabling high power consuming devices when they predict that a target is arriving in their coverage area, while enabling low power consuming devices when the target is absent. Each node has a Probabilistic Finite State Automaton which acts as a supervisor to dynamically control its various sensing and communication devices based on target's predicted position. The POSE algorithm is validated by extensive Monte Carlo simulations and compared with random scheduling schemes. The results show that the POSE algorithm provides significant energy savings while also improving track estimation via fusion-driven state initialization.

  1. Well-posed continuum equations for granular flow with compressibility and μ(I)-rheology.

    PubMed

    Barker, T; Schaeffer, D G; Shearer, M; Gray, J M N T

    2017-05-01

    Continuum modelling of granular flow has been plagued with the issue of ill-posed dynamic equations for a long time. Equations for incompressible, two-dimensional flow based on the Coulomb friction law are ill-posed regardless of the deformation, whereas the rate-dependent μ(I)-rheology is ill-posed when the non-dimensional inertial number I is too high or too low. Here, incorporating ideas from critical-state soil mechanics, we derive conditions for well-posedness of partial differential equations that combine compressibility with I-dependent rheology. When the I-dependence comes from a specific friction coefficient μ(I), our results show that, with compressibility, the equations are well-posed for all deformation rates provided that μ(I) satisfies certain minimal, physically natural, inequalities.

  2. A Discrete Model for an Ill-Posed Nonlinear Parabolic PDE

    DTIC Science & Technology

    2001-02-23

    analysis also has implications to related ill posed nonlinear PDEs for the one- dimensional Perona - Malik equation in image processing and to models for clustering instabilities in granular materials.

  3. Estimating aquatic hazards posed by prescription pharmaceutical residues from municipal wastewater

    EPA Science Inventory

    Risks posed by pharmaceuticals in the environment are hard to estimate due to limited monitoring capacity and difficulty interpreting monitoring results. In order to partially address these issues, we suggest a method for prioritizing pharmaceuticals for monitoring, and a framewo...

  4. Well-posed continuum equations for granular flow with compressibility and μ(I)-rheology

    PubMed Central

    Schaeffer, D. G.; Shearer, M.; Gray, J. M. N. T.

    2017-01-01

    Continuum modelling of granular flow has been plagued with the issue of ill-posed dynamic equations for a long time. Equations for incompressible, two-dimensional flow based on the Coulomb friction law are ill-posed regardless of the deformation, whereas the rate-dependent μ(I)-rheology is ill-posed when the non-dimensional inertial number I is too high or too low. Here, incorporating ideas from critical-state soil mechanics, we derive conditions for well-posedness of partial differential equations that combine compressibility with I-dependent rheology. When the I-dependence comes from a specific friction coefficient μ(I), our results show that, with compressibility, the equations are well-posed for all deformation rates provided that μ(I) satisfies certain minimal, physically natural, inequalities. PMID:28588402

  5. Estimating aquatic hazards posed by prescription pharmaceutical residues from municipal wastewater

    EPA Science Inventory

    Risks posed by pharmaceuticals in the environment are hard to estimate due to limited monitoring capacity and difficulty interpreting monitoring results. In order to partially address these issues, we suggest a method for prioritizing pharmaceuticals for monitoring, and a framewo...

  6. View of Anderson posing for a photo in the SM during Expedition 15

    NASA Image and Video Library

    2007-07-21

    ISS015-E-18872 (21 July 2007) --- Astronaut Clay Anderson, Expedition 15 flight engineer, poses for a photo with food packets floating freely in the Zvezda Service Module of the International Space Station.

  7. View of Anderson posing for a photo in the US Lab during Expedition 15

    NASA Image and Video Library

    2007-09-03

    ISS015-E-27279 (3 Sept. 2007) --- NASA astronaut Clay Anderson, Expedition 15 flight engineer, poses for a photo near the Earth observation window in the Destiny laboratory of the International Space Station.

  8. View of Anderson posing for photo in the A/L during Expedition 15

    NASA Image and Video Library

    2007-07-19

    ISS015-E-19537 (19 July 2007) --- Astronaut Clay Anderson, Expedition 15 flight engineer, poses for a photo with two extravehicular mobility units (EMU) in the Quest Airlock of the International Space Station

  9. Anderson and Kotov posing for a photo in the US Lab during Expedition 15

    NASA Image and Video Library

    2007-10-01

    ISS015-E-32309 (October 2007) --- NASA astronaut Clay Anderson (left) and Russian Federal Space Agency cosmonaut Oleg V. Kotov, both Expedition 15 flight engineers, pose for a photo in the Destiny laboratory of the International Space Station.

  10. Improved pose and affinity predictions using different protocols tailored on the basis of data availability

    NASA Astrophysics Data System (ADS)

    Prathipati, Philip; Nagao, Chioko; Ahmad, Shandar; Mizuguchi, Kenji

    2016-09-01

    The D3R 2015 grand drug design challenge provided a set of blinded challenges for evaluating the applicability of our protocols for pose and affinity prediction. In the present study, we report the application of two different strategies for the two D3R protein targets HSP90 and MAP4K4. HSP90 is a well-studied target system with numerous co-crystal structures and SAR data. Furthermore the D3R HSP90 test compounds showed high structural similarity to existing HSP90 inhibitors in BindingDB. Thus, we adopted an integrated docking and scoring approach involving a combination of both pharmacophoric and heavy atom similarity alignments, local minimization and quantitative structure activity relationships modeling, resulting in the reasonable prediction of pose [with the root mean square deviation (RMSD) values of 1.75 Å for mean pose 1, 1.417 Å for the mean best pose and 1.85 Å for the mean all poses] and affinity (ROC AUC = 0.702 at 7.5 pIC50 cut-off and R = 0.45 for 180 compounds). The second protein, MAP4K4, represents a novel system with limited SAR and co-crystal structure data and little structural similarity of the D3R MAP4K4 test compounds to known MAP4K4 ligands. For this system, we implemented an exhaustive pose and affinity prediction protocol involving docking and scoring using the PLANTS software which considers side chain flexibility together with protein-ligand fingerprints analysis assisting in pose prioritization. This protocol through fares poorly in pose prediction (with the RMSD values of 4.346 Å for mean pose 1, 4.69 Å for mean best pose and 4.75 Å for mean all poses) and produced reasonable affinity prediction (AUC = 0.728 at 7.5 pIC50 cut-off and R = 0.67 for 18 compounds, ranked 1st among 80 submissions).

  11. 3D hand pose estimation using Kinect enhanced with recovery method

    NASA Astrophysics Data System (ADS)

    Thanyadit, Santawat; Madarasami, Suthep

    2013-07-01

    We present an improved approach to another previous work on 3D hand tracking that also uses the Microsoft Kinect sensor. The previous implementation tracks the position, orientation, and full articulation from marker-less visual observations provided by Kinect. As an optimization problem, the objective of hand tracking is to minimize the difference between a hand gesture depth image obtained from Kinect and a hypothesized 3-D hand model. The previous method of relied heavily on the best current frame result, skin detection data, and depth data, often resulting in a "losttrack state" with unrecoverable error, especially when the hand moved faster than the per-frame processing speed. To recover from the lost track state, we use the skeleton joint data from Kinect to determine hand position, instead of relying on skin data. This joint data is also used to limit the search range of our Particle Swarm Optimization (PSO), allowing for a more efficient search. Consequently, the fewer generations required to obtain a result enables us to achieve higher frame-rate processing. The computationally intensive step in matching the observed hand depth with the hypothesized hand pose is accelerated using a GPGPU processor. The proposed method also improves reliability by adding a recovery mechanism for quick hand movements, eliminating the need for manual hand position initialization by a user. Our method does not depend on skin color detection and, therefore, avoids errors common in incorrect or extra skin detection. Thus, a user need not hide arm skin by wearing long-sleeve clothing, for example.

  12. Simulated Lidar Images of Human Pose using a 3DS Max Virtual Laboratory

    DTIC Science & Technology

    2015-12-01

    AFRL-RH-WP-TR-2015-0089 SIMULATED LIDAR IMAGES OF HUMAN POSE USING A 3DS MAX VIRTUAL LABORATORY Jeanne Smith Isiah Davenport Infoscitex Corp...Images of Human Pose using a 3DS Max Virtual Laboratory 5a. CONTRACT NUMBER In-House 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62202F 6...learning techniques. To produce these large sets of point clouds in an efficient and repeatable manner, a virtual laboratory environment was

  13. A review of cooperative and uncooperative spacecraft pose determination techniques for close-proximity operations

    NASA Astrophysics Data System (ADS)

    Opromolla, Roberto; Fasano, Giancarmine; Rufino, Giancarlo; Grassi, Michele

    2017-08-01

    The capability of an active spacecraft to accurately estimate its relative position and attitude (pose) with respect to an active/inactive, artificial/natural space object (target) orbiting in close-proximity is required to carry out various activities like formation flying, on-orbit servicing, active debris removal, and space exploration. According to the specific mission scenario, the pose determination task involves both theoretical and technological challenges related to the search for the most suitable algorithmic solution and sensor architecture, respectively. As regards the latter aspect, electro-optical sensors represent the best option as their use is compatible with mass and power limitation of micro and small satellites, and their measurements can be processed to estimate all the pose parameters. Overall, the degree of complexity of the challenges related to pose determination largely varies depending on the nature of the targets, which may be actively/passively cooperative, uncooperative but known, or uncooperative and unknown space objects. In this respect, while cooperative pose determination has been successfully demonstrated in orbit, the uncooperative case is still under study by universities, research centers, space agencies and private companies. However, in both the cases, the demand for space applications involving relative navigation maneuvers, also in close-proximity, for which pose determination capabilities are mandatory, is significantly increasing. In this framework, a review of state-of-the-art techniques and algorithms developed in the last decades for cooperative and uncooperative pose determination by processing data provided by electro-optical sensors is herein presented. Specifically, their main advantages and drawbacks in terms of achieved performance, computational complexity, and sensitivity to variability of pose and target geometry, are highlighted.

  14. Consistently Showing Your Best Side? Intra-individual Consistency in #Selfie Pose Orientation.

    PubMed

    Lindell, Annukka K

    2017-01-01

    Painted and photographic portraits of others show an asymmetric bias: people favor their left cheek. Both experimental and database studies confirm that the left cheek bias extends to selfies. To date all such selfie studies have been cross-sectional; whether individual selfie-takers tend to consistently favor the same pose orientation, or switch between multiple poses, remains to be determined. The present study thus examined intra-individual consistency in selfie pose orientations. Two hundred selfie-taking participants (100 male and 100 female) were identified by searching #selfie on Instagram. The most recent 10 single-subject selfies for the each of the participants were selected and coded for type of selfie (normal; mirror) and pose orientation (left, midline, right), resulting in a sample of 2000 selfies. Results indicated that selfie-takers do tend to consistently adopt a preferred pose orientation (α = 0.72), with more participants showing an overall left cheek bias (41%) than would be expected by chance (overall right cheek bias = 31.5%; overall midline bias = 19.5%; no overall bias = 8%). Logistic regression modellng, controlling for the repeated measure of participant identity, indicated that sex did not affect pose orientation. However, selfie type proved a significant predictor when comparing left and right cheek poses, with a stronger left cheek bias for mirror than normal selfies. Overall, these novel findings indicate that selfie-takers show intra-individual consistency in pose orientation, and in addition, replicate the previously reported left cheek bias for selfies and other types of portrait, confirming that the left cheek bias also presents within individuals' selfie corpora.

  15. STS-26 crewmembers pose for onboard portrait on middeck with 51L mementos

    NASA Technical Reports Server (NTRS)

    1988-01-01

    STS-26 crewmembers, each wearing a red, white, or blue polo shirt, pose for onboard crew portrait on Discovery's, Orbiter Vehicle (OV) 103's, middeck with STS-51L crew portrait, its flight (crew) insignia, and the STS-26 flight (crew) insignia. Left to right are Mission Specialist (MS) David C. Hilmers, MS George D. Nelson, Commander Frederick H. Hauck, MS John M. Lounge, and Pilot Richard O. Covey (front). The crewmembers pose in front of the port side wall.

  16. STS-26 crewmembers pose for onboard portrait on middeck with 51L mementos

    NASA Technical Reports Server (NTRS)

    1988-01-01

    STS-26 crewmembers, each wearing a red, white, or blue polo shirt, pose for onboard crew portrait on Discovery's, Orbiter Vehicle (OV) 103's, middeck with STS-51L crew portrait, its flight (crew) insignia, and the STS-26 flight (crew) insignia. Left to right are Mission Specialist (MS) David C. Hilmers, MS George D. Nelson, Commander Frederick H. Hauck, MS John M. Lounge, and Pilot Richard O. Covey (front). The crewmembers pose in front of the port side wall.

  17. Consistently Showing Your Best Side? Intra-individual Consistency in #Selfie Pose Orientation

    PubMed Central

    Lindell, Annukka K.

    2017-01-01

    Painted and photographic portraits of others show an asymmetric bias: people favor their left cheek. Both experimental and database studies confirm that the left cheek bias extends to selfies. To date all such selfie studies have been cross-sectional; whether individual selfie-takers tend to consistently favor the same pose orientation, or switch between multiple poses, remains to be determined. The present study thus examined intra-individual consistency in selfie pose orientations. Two hundred selfie-taking participants (100 male and 100 female) were identified by searching #selfie on Instagram. The most recent 10 single-subject selfies for the each of the participants were selected and coded for type of selfie (normal; mirror) and pose orientation (left, midline, right), resulting in a sample of 2000 selfies. Results indicated that selfie-takers do tend to consistently adopt a preferred pose orientation (α = 0.72), with more participants showing an overall left cheek bias (41%) than would be expected by chance (overall right cheek bias = 31.5%; overall midline bias = 19.5%; no overall bias = 8%). Logistic regression modellng, controlling for the repeated measure of participant identity, indicated that sex did not affect pose orientation. However, selfie type proved a significant predictor when comparing left and right cheek poses, with a stronger left cheek bias for mirror than normal selfies. Overall, these novel findings indicate that selfie-takers show intra-individual consistency in pose orientation, and in addition, replicate the previously reported left cheek bias for selfies and other types of portrait, confirming that the left cheek bias also presents within individuals’ selfie corpora. PMID:28270790

  18. Problemes poses par la mesure du rendement en francais des eleves franco-ontariens (Problems Posed by the Measurement of Proficiency in French Among Franco-Ontarian Students). Working Papers on Bilingualism, No. 16.

    ERIC Educational Resources Information Center

    Canale, Michael; Mougeon, Raymond

    This study examines the hypothesis that the French used by a large number of Franco-Ontarians represents a linguistic system (or several systems) that differs from Standard French. In addition, a review of previous research leads to the inverse hypothesis, that Ontarian French represents a body of different systems or sub-systems that are more or…

  19. Discrimination analysis using multi-object statistics of shape and pose

    NASA Astrophysics Data System (ADS)

    Gorczowski, Kevin; Styner, Martin; Jeong, Ja Yeon; Marron, J. S.; Piven, Joseph; Hazlett, Heather Cody; Pizer, Stephen M.; Gerig, Guido

    2007-03-01

    A main focus of statistical shape analysis is the description of variability of a population of geometric objects. In this paper, we present work towards modeling the shape and pose variability of sets of multiple objects. Principal geodesic analysis (PGA) is the extension of the standard technique of principal component analysis (PCA) into the nonlinear Riemannian symmetric space of pose and our medial m-rep shape description, a space in which use of PCA would be incorrect. In this paper, we discuss the decoupling of pose and shape in multi-object sets using different normalization settings. Further, we introduce methods of describing the statistics of object pose and object shape, both separately and simultaneously using a novel extension of PGA. We demonstrate our methods in an application to a longitudinal pediatric autism study with object sets of 10 subcortical structures in a population of 47 subjects. The results show that global scale accounts for most of the major mode of variation across time. Furthermore, the PGA components and the corresponding distribution of different subject groups vary significantly depending on the choice of normalization, which illustrates the importance of global and local pose alignment in multi-object shape analysis. Finally, we present results of using distance weighted discrimination analysis (DWD) in an attempt to use pose and shape features to separate subjects according to diagnosis, as well as visualize discriminating differences.

  20. A new pose measurement system based on orthogonal beam splitting imaging configuration

    NASA Astrophysics Data System (ADS)

    Liu, Xintong; Sun, Changku; Wang, Peng

    2015-08-01

    A new pose measurement system based on orthogonal beam splitting imaging is proposed in this paper to solve the contradictions between the measurement accuracy and measurement speed in the existing pose measurement method of monocular or binocular vision with multi-linear CCDs. In the system, monocular object lens with beam splitting structure and two linear CCDs are combined to compose the pose measurement sensor. Monocular camera helps the system gain a large field of view. And the two orthogonally placed linear CCDs are equal to one array CCD. Furthermore, linear CCD possesses the advantage of high-resolution imaging, high-speed data capturing and high-efficiency data processing as compared to an array one. The key work of this paper lies in designing the optical structure of the sensor, calibrating the parameters of the camera corresponding to its model, and solving pose of the object by corresponding position algorithm. The experimental results prove that the measurement accuracy (2%) of orthogonally-splitting-imaging pose sensor can be achieved. Hence, this system meets the high-speed and high-precision measurement requirements in wide space and can be applied to pose measurement in aerospace and vehicle field.

  1. Comparative assessment of techniques for initial pose estimation using monocular vision

    NASA Astrophysics Data System (ADS)

    Sharma, Sumant; D`Amico, Simone

    2016-06-01

    This work addresses the comparative assessment of initial pose estimation techniques for monocular navigation to enable formation-flying and on-orbit servicing missions. Monocular navigation relies on finding an initial pose, i.e., a coarse estimate of the attitude and position of the space resident object with respect to the camera, based on a minimum number of features from a three dimensional computer model and a single two dimensional image. The initial pose is estimated without the use of fiducial markers, without any range measurements or any apriori relative motion information. Prior work has been done to compare different pose estimators for terrestrial applications, but there is a lack of functional and performance characterization of such algorithms in the context of missions involving rendezvous operations in the space environment. Use of state-of-the-art pose estimation algorithms designed for terrestrial applications is challenging in space due to factors such as limited on-board processing power, low carrier to noise ratio, and high image contrasts. This paper focuses on performance characterization of three initial pose estimation algorithms in the context of such missions and suggests improvements.

  2. Muscle utilization patterns vary by skill levels of the practitioners across specific yoga poses (asanas).

    PubMed

    Ni, Meng; Mooney, Kiersten; Balachandran, Anoop; Richards, Luca; Harriell, Kysha; Signorile, Joseph F

    2014-08-01

    To compare muscle activation patterns in 14 dominant side muscles during different yoga poses across three skill levels. Mixed repeated-measures descriptive study. University neuromuscular research laboratory, Miami, US. A group of 36 yoga practitioners (9 M/27 F; mean ± SD, 31.6 ± 12.6 years) with at least 3 months yoga practice experience. Each of the 11 surya namaskar poses A and B was performed separately for 15s and the surface electromyography for 14 muscles were recorded. Normalized root mean square of the electromyographic signal (NrmsEMG) for 14 muscles (5 upper body, 4 trunk, 5 lower body). There were significant main effects of pose for all fourteen muscles except middle trapezius (p<.02) and of skill level for the vastus medialis; p=.027). A significant skill level × pose interaction existed for five muscles (pectoralis major sternal head, anterior deltoid, medial deltoid, upper rectus abdominis and gastrocnemius lateralis; p<.05). Post hoc analyses using Bonferroni comparisons indicated that different poses activated specific muscle groups; however, this varied by skill level. Our results indicate that different poses can produce specific muscle activation patterns which may vary due to practitioners' skill levels. This information can be used in designing rehabilitation and training programs and for cuing during yoga training. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Automatic pose correction for image-guided nonhuman primate brain surgery planning

    NASA Astrophysics Data System (ADS)

    Ghafurian, Soheil; Chen, Antong; Hines, Catherine; Dogdas, Belma; Bone, Ashleigh; Lodge, Kenneth; O'Malley, Stacey; Winkelmann, Christopher T.; Bagchi, Ansuman; Lubbers, Laura S.; Uslaner, Jason M.; Johnson, Colena; Renger, John; Zariwala, Hatim A.

    2016-03-01

    Intracranial delivery of recombinant DNA and neurochemical analysis in nonhuman primate (NHP) requires precise targeting of various brain structures via imaging derived coordinates in stereotactic surgeries. To attain targeting precision, the surgical planning needs to be done on preoperative three dimensional (3D) CT and/or MR images, in which the animals head is fixed in a pose identical to the pose during the stereotactic surgery. The matching of the image to the pose in the stereotactic frame can be done manually by detecting key anatomical landmarks on the 3D MR and CT images such as ear canal and ear bar zero position. This is not only time intensive but also prone to error due to the varying initial poses in the images which affects both the landmark detection and rotation estimation. We have introduced a fast, reproducible, and semi-automatic method to detect the stereotactic coordinate system in the image and correct the pose. The method begins with a rigid registration of the subject images to an atlas and proceeds to detect the anatomical landmarks through a sequence of optimization, deformable and multimodal registration algorithms. The results showed similar precision (maximum difference of 1.71 in average in-plane rotation) to a manual pose correction.

  4. Photographic and videographic assessment of the smile: objective and subjective evaluations of posed and spontaneous smiles.

    PubMed

    Walder, Joan F; Freeman, Katherine; Lipp, Mitchell J; Nicolay, Olivier F; Cisneros, George J

    2013-12-01

    Esthetic considerations play an increasingly important role in patient care, and clinicians need a methodology that includes imaging techniques to capture the dynamic nature of the smile. Photographs of the posed smile are routinely used to guide diagnosis and treatment, but there is no standardized and validated method for recording the dynamic smile. The purposes of this study were to (1) determine whether a posed smile is reproducible, (2) compare visual and verbal cues in eliciting a smile, and (3) compare the diagnostic value of videography and photography in evaluating a patient's smile. The smiles of 22 subjects were simultaneously photographed and videotaped on 2 separate occasions. For objective comparisons, measurements of the smile were obtained from 8 × 10 color still photographs and selected digitized video images. A panel consisting of a layperson, an oral surgeon, an orthodontist, and a prosthodontist subjectively assessed the reproducibility of the smile, posed vs spontaneous smiles, and the diagnostic value of video vs still images. Objective measurements showed that the posed smile can be reliably reproduced, whether captured by videography or still photography. However, subjectively, the panel members detected differences between the posed smiles taken on different days 80% of the time. The clinician panel members expressed a strong preference for videography over photography and for the spontaneous over the posed smiles. This study emphasizes the need to continue to investigate and standardize the methods of eliciting and recording a smile of diagnostic quality. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  5. Problem Solving

    ERIC Educational Resources Information Center

    Kinsella, John J.

    1970-01-01

    Discussed are the nature of a mathematical problem, problem solving in the traditional and modern mathematics programs, problem solving and psychology, research related to problem solving, and teaching problem solving in algebra and geometry. (CT)

  6. A Two-Stage Bayesian Network Method for 3D Human Pose Estimation from Monocular Image Sequences

    NASA Astrophysics Data System (ADS)

    Wang, Yuan-Kai; Cheng, Kuang-You

    2010-12-01

    This paper proposes a novel human motion capture method that locates human body joint position and reconstructs the human pose in 3D space from monocular images. We propose a two-stage framework including 2D and 3D probabilistic graphical models which can solve the occlusion problem for the estimation of human joint positions. The 2D and 3D models adopt directed acyclic structure to avoid error propagation of inference. Image observations corresponding to shape and appearance features of humans are considered as evidence for the inference of 2D joint positions in the 2D model. Both the 2D and 3D models utilize the Expectation Maximization algorithm to learn prior distributions of the models. An annealed Gibbs sampling method is proposed for the two-stage method to inference the maximum posteriori distributions of joint positions. The annealing process can efficiently explore the mode of distributions and find solutions in high-dimensional space. Experiments are conducted on the HumanEva dataset with image sequences of walking motion, which has challenges of occlusion and loss of image observations. Experimental results show that the proposed two-stage approach can efficiently estimate more accurate human poses.

  7. How is this child feeling? Preschool-aged children’s ability to recognize emotion in faces and body poses

    PubMed Central

    Parker, Alison E.; Mathis, Erin T.; Kupersmidt, Janis B.

    2016-01-01

    The study examined children’s recognition of emotion from faces and body poses, as well as gender differences in these recognition abilities. Preschool-aged children (N = 55) and their parents and teachers participated in the study. Preschool-aged children completed a web-based measure of emotion recognition skills, which included five tasks (three with faces and two with bodies). Parents and teachers reported on children’s aggressive behaviors and social skills. Children’s emotion accuracy on two of the three facial tasks and one of the body tasks was related to teacher reports of social skills. Some of these relations were moderated by child gender. In particular, the relationships between emotion recognition accuracy and reports of children’s behavior were stronger for boys than girls. Identifying preschool-aged children’s strengths and weaknesses in identification of emotion from faces and body poses may be helpful in guiding interventions with children who have problems with social and behavioral functioning that may be due, in part, to emotional knowledge deficits. Further developmental implications of these findings are discussed. PMID:27057129

  8. A well-posed numerical method to track isolated conformal map singularities in Hele-Shaw flow

    NASA Technical Reports Server (NTRS)

    Baker, Gregory; Siegel, Michael; Tanveer, Saleh

    1995-01-01

    We present a new numerical method for calculating an evolving 2D Hele-Shaw interface when surface tension effects are neglected. In the case where the flow is directed from the less viscous fluid into the more viscous fluid, the motion of the interface is ill-posed; small deviations in the initial condition will produce significant changes in the ensuing motion. This situation is disastrous for numerical computation, as small round-off errors can quickly lead to large inaccuracies in the computed solution. Our method of computation is most easily formulated using a conformal map from the fluid domain into a unit disk. The method relies on analytically continuing the initial data and equations of motion into the region exterior to the disk, where the evolution problem becomes well-posed. The equations are then numerically solved in the extended domain. The presence of singularities in the conformal map outside of the disk introduces specific structures along the fluid interface. Our method can explicitly track the location of isolated pole and branch point singularities, allowing us to draw connections between the development of interfacial patterns and the motion of singularities as they approach the unit disk. In particular, we are able to relate physical features such as finger shape, side-branch formation, and competition between fingers to the nature and location of the singularities. The usefulness of this method in studying the formation of topological singularities (self-intersections of the interface) is also pointed out.

  9. Technical and organizational solutions to problems of electromagnetic compatibility posed by the development of the TRANSRAPID test facility, England

    NASA Astrophysics Data System (ADS)

    Pilz, W. D.; Ferger, P.

    1981-09-01

    Disadvantages of magnetic levitation technology related to a transportation system network, linking a metropolitan center with outlying regions are enumerated. Further development of an energy efficient, high speed system for long distance travel necessitates prevention of possible electromagnetic hazards. Lightning generation by the charged components of the system, like swept stroke phenomena is treated. Electrostatic interference from the system is noted and further developments are required to exploit high speed potential.

  10. Reflective Analysis as a Tool for Task Redesign: The Case of Prospective Elementary Teachers Solving and Posing Fraction Comparison Problems

    ERIC Educational Resources Information Center

    Thanheiser, Eva; Olanoff, Dana; Hillen, Amy; Feldman, Ziv; Tobias, Jennifer M.; Welder, Rachael M.

    2016-01-01

    Mathematical task design has been a central focus of the mathematics education research community over the last few years. In this study, six university teacher educators from six different US institutions formed a community of practice to explore key aspects of task design (planning, implementing, reflecting, and modifying) in the context of…

  11. Differentiating Instruction Using a Virtual Environment: A Study of Mathematical Problem Posing among Gifted and Talented Learners

    ERIC Educational Resources Information Center

    Manuel, Dominic; Freiman, Viktor

    2017-01-01

    Meeting the needs of mathematically gifted and talented students is a challenge for educators. To support teachers of mathematically gifted and talented students to find appropriate solutions, several innovative projects were conducted in schools using funds provided by the New Brunswick, Canada, Department of Education. This article presents one…

  12. Numerical reconstruction of photon-number statistics from photocounting statistics: Regularization of an ill-posed problem

    SciTech Connect

    Starkov, V. N.; Semenov, A. A.; Gomonay, H. V.

    2009-07-15

    We demonstrate a practical possibility of loss compensation in measured photocounting statistics in the presence of dark counts and background radiation noise. It is shown that satisfactory results are obtained even in the case of low detection efficiency and large experimental errors.

  13. Reflective Analysis as a Tool for Task Redesign: The Case of Prospective Elementary Teachers Solving and Posing Fraction Comparison Problems

    ERIC Educational Resources Information Center

    Thanheiser, Eva; Olanoff, Dana; Hillen, Amy; Feldman, Ziv; Tobias, Jennifer M.; Welder, Rachael M.

    2016-01-01

    Mathematical task design has been a central focus of the mathematics education research community over the last few years. In this study, six university teacher educators from six different US institutions formed a community of practice to explore key aspects of task design (planning, implementing, reflecting, and modifying) in the context of…

  14. Problem-Posing in a Primary Grade Classroom: Utilizing Freire's Methods to Break the Culture of Silence

    ERIC Educational Resources Information Center

    Reed, Judith; Saunders, Karen; Pfadenhauer-Simonds, Susan

    2015-01-01

    Using Paulo Freire's, idea that the aim of education must always be to transform the world so as to liberate oppressed peoples. The authors: Reed, Saunders, and Pfadenhauer-Simonds address this issue by noting that state-backed education systems in the United States, as elsewhere, arguably can be seen as supporting repressive forces that keep…

  15. Problem-Posing in a Primary Grade Classroom: Utilizing Freire's Methods to Break the Culture of Silence

    ERIC Educational Resources Information Center

    Reed, Judith; Saunders, Karen; Pfadenhauer-Simonds, Susan

    2015-01-01

    Using Paulo Freire's, idea that the aim of education must always be to transform the world so as to liberate oppressed peoples. The authors: Reed, Saunders, and Pfadenhauer-Simonds address this issue by noting that state-backed education systems in the United States, as elsewhere, arguably can be seen as supporting repressive forces that keep…

  16. [Selected problems in the forensic-psychiatric evaluation of persons posing a likelihood of repeating a criminal act].

    PubMed

    Florkowski, Antoni; Zboralski, Krzysztof; Nowacka, Agata; Strójwas, Krzysztof; Flinik-Jankowska, Magdalena; Konopa, Aleksandra; Łacisz, Joanna; Wierzbiński, Piotr

    2014-09-01

    In the current penal code, compared to previous regulations, there have been alterations concerning medical security measures. These amendments have been prompted by socio-politic circumstances in Poland as well as implementation of Mental Health Act. According to the current law the court, on the request of expert psychiatrists, can pronounce a sentence of obligatory stay in psychiatric institution for perpetrator of criminal act who has been deemed not sane due to 31 subsection 1 of penal code and who is predictably able of recidivism. In legal-medical practice those less experienced expert psychiatrists may encounter difficulties producing expertise for the court, especially evaluating probability of recurrence of committing a criminal act and resulting request for psychiatric detention. In order to make this issue more acquainted we present a review of literature concerning it.

  17. Current Aeromedical Issues in Rotary Wing Operations. (Problemes actuels de medecine aeronautique poses par les operations utilisant des voilures tournantes)

    DTIC Science & Technology

    1999-08-01

    specific duration. Such Technical Teams can organise workshops, symposia, field trials, lecture series and training courses. An important function of...is used fluctuations in communications patterns, for given information of the functional status of suggesting the potential utility of the system the...no change of heading or height. Both the deceleration and the function . nose-up pitch associated with the attitude change at the final stages of

  18. Variations in Both-Addends-Unknown Problems

    ERIC Educational Resources Information Center

    Champagne, Zachary M.; Schoen, Robert; Riddell, Claire M.

    2014-01-01

    Early elementary school students are expected to solve twelve distinct types of word problems. A math researcher and two teachers pose a structure for thinking about one problem type that has not been studied as closely as the other eleven. In this article, the authors share some of their discoveries with regard to the variety of…

  19. Boundary Value Problems With Integral Conditions

    NASA Astrophysics Data System (ADS)

    Karandzhulov, L. I.; Sirakova, N. D.

    2011-12-01

    The weakly perturbed nonlinear boundary value problems (BVP) for almost linear systems of ordinary differential equations (ODE) are considered. We assume that the nonlinear part contain an additional function, which defines the perturbation as singular. Then the Poincare method is not applicable. The problem of existence, uniqueness and construction of a solution of the posed BVP with integral condition is studied.

  20. Addressing Community Gang Problems: A Practical Guide. Monograph.

    ERIC Educational Resources Information Center

    Police Executive Research Forum, Washington, DC.

    This monograph provides guidelines for agencies and community groups to develop individualized responses to local gang problems. The manual contains a foundation for understanding the diverse nature of gangs, the problems they pose, and the harm they cause. Two models are presented for addressing gang-related problems. The problem-solving model to…