WorldWideScience

Sample records for surveys classroom artifacts

  1. Classroom Assessment Practices: A Survey of Botswana Primary and Secondary School Teachers

    Science.gov (United States)

    Koloi-Keaikitse, Setlhomo

    2012-01-01

    The Classroom Assessment Practices and Skills (CAPS) questionnaire was administered to a sample of 691 primary and secondary school teachers in Botswana, Southern Africa to survey their thoughts about classroom assessment and identify classroom assessment practices teachers perceive to be skilled and those that they used most. The study examined…

  2. Classroom Technology in Business Schools: A Survey of Installations and Attitudes toward Teaching and Learning

    Science.gov (United States)

    Parker, Betty; Burnie, David

    2009-01-01

    A survey of administrators and faculty of AACSB-accredited business schools provided insights into current classroom technology infrastructure, attitudes towards technology and learning, and the use of web course tools in business school classrooms. The results of the survey provided four major findings: business schools are utilizing high levels…

  3. Common Core Math in the K-8 Classroom: Results from a National Teacher Survey

    Science.gov (United States)

    Bay-Williams, Jennifer

    2016-01-01

    Successful implementation of the Common Core State Standards for Mathematics (CCSS-M) should result in noticeable differences in primary and middle school math classrooms across the United States. "Common Core Math in the K-8 Classroom: Results from a National Teacher Survey" takes a close look at how educators are implementing the…

  4. Classroom

    Indian Academy of Sciences (India)

    CLASSROOM. 378. RESONANCE │ April 2012. Classroom. In this section of Resonance, we invite readers to pose questions likely to be raised in a classroom ... or both. “Classroom” is equally a forum for raising broader issues and sharing personal ..... In the present investigation, a question may arise as to what will be ...

  5. Dynamics in artifact ecologies

    DEFF Research Database (Denmark)

    Bødker, Susanne; Klokmose, Clemens Nylandsted

    2012-01-01

    artifacts influence the use of others. Understanding this interplay becomes more and more essential for interaction design as our artifact ecologies grow. This paper continues a recent discourse on artifact ecologies. Through interviews with iPhone users, we demonstrate that relationships between artifacts...

  6. Classroom

    Indian Academy of Sciences (India)

    In this section of Resonance, we invite readers to pose questions likely to be raised in a classroom situation. We may suggest strategies for dealing with them, or invitt responses, or both. "Classroom" is equally a forum for raising broader issues and sharing personal experiences and viewpoints on matters related to teaching ...

  7. Classroom

    Indian Academy of Sciences (India)

    In this section of Resonance, we invite readers to pose questions likely to be raised in a classroom situation. We may suggest strategies for dealing with them, or invite responses, or both. "Classroom" is equally a forum for raising broader issues and sharing personal experiences and viewpoints on matters related to ...

  8. Classroom

    Indian Academy of Sciences (India)

    In this section of Resonance, we invite readers to pose questions likely to be raised in a classroom situation. We may suggest strategies for dealing with th,em, or invite responses, or both. "Classroom" is equally ti forum for raising broader issues and sharing personal experiences and viewpoints on matters related to ...

  9. Classroom

    Indian Academy of Sciences (India)

    group that was not yet exposed to this learning environment. Although the ... environment [15]. The Green Classroom. The 'Green classroom' is an environmental education program that wants to address knowledge, skills and attitude at the same time. ..... programme on children´s perception of biodiversity, The Journal.

  10. Classroom

    Indian Academy of Sciences (India)

    Classroom. In this section of Resonance, we in'Vite readers to pose questions likely to be raised in a classroom situation. We may suggest strategies for dealing with them, or in'Vite .... boron-10 which demonstrated that some very beautiful work done by a. Caltech group headed by T Lauritsen and W A Fowler was wrong.

  11. Classroom

    Indian Academy of Sciences (India)

    In this section of Resonance, we invite readers to pose questions likely to be raised in a classroom situation. We may suggest strategies for dealing with them, or invite responses, or botlt. "Classroom" is equally a forum for raising broader issues and sharing personal experiences and viewpoints on matters related to ...

  12. Classroom

    Indian Academy of Sciences (India)

    body. A frame of reference is clearly an abstract artifact and it is wrong to think that it is limited by the spatial extension of the. Arvind Kumar is the Director, body or that it 'terminates' at the boundary of the body. Yet, this. Homi Bhabha .... visual representation of distance by width in the first case is so strong that students ...

  13. Dealing with Diversity Issues in the Classroom: A Survey of the STP Membership

    Science.gov (United States)

    Prieto, Loreto R.; Whittlesey, Valerie; Herbert, Diane; Ocampo, Carlota; Schomburg, Allison; So, Dominicus

    2009-01-01

    We examined how psychology educators regarded and addressed diversity issues in their classrooms. The approximately 650 psychology educators who took part in this survey indicated a high level of personal acceptance of diverse persons and acknowledged the importance of infusing diversity issues into courses across the psychology curriculum. Our…

  14. Survey of 800+ datasets from human tissue and body fluid reveals XenomiRs are likely artifacts

    DEFF Research Database (Denmark)

    Kang, Wenjing; Bang-Berthelsen, Claus Heiner; Holm, Anja

    2017-01-01

    -study in the field, surveying the presence and abundances of cross-species miRNAs (xenomiRs) in 824 sequencing datasets from various human tissues and body fluids. We find that xenomiRs are commonly present in tissues (17%) and body fluids (69%), however the abundances are low, comprising 0.001% of host human mi...

  15. Sexualidade na sala de aula: tecendo aprendizagens a partir de um artefato pedagógico Sexuality in the classroom: weaving learning experiences from a pedagogical artifact

    Directory of Open Access Journals (Sweden)

    Benícia Oliveira da Silva

    2011-08-01

    Full Text Available Neste artigo, discutimos a seção Sexo da revista Capricho como um artefato cultural. Em nossas discussões, compreendemos que esse artefato constitui-se em uma pedagogia cultural que produz e divulga significados acerca da temática sexualidade, operando não apenas como fonte de informação ou entretenimento. Esse artefato, além de possibilitar a discussão de questões como sistemas genitais, métodos contraceptivos, Aids e DST, que já estão presentes nos currículos escolares e nos Parâmetros Curriculares Nacionais (PCN, promove a inclusão de temas acerca de anseios, medos, prazeres, comportamento, gênero e corpo que nem sempre são abordados nos currículos, problematizando, assim, diferentes representações e significados atribuídos à sexualidade e que circulam em nossa sociedade.In this article, we discuss the section Sexo of Capricho magazine as a cultural artifact. We understand that this artifact consists in a cultural pedagogy which produces and disseminates meanings on the theme of sexuality, operating it not only as a source of information or entertainment , but as a teaching tool that, besides allowing the discussion of issues such as genital systems, contraceptive methods, AIDS and STD, that are already present in the school curriculum and the National Curriculum Parameters (PCN, promotes the inclusion of yearnings, fears, pleasures, behavior, gender, that are not always approached in the curriculum, thereby problematizing different representations and meanings attributed to sexuality in our society.

  16. A method to eliminate refraction artifacts in EM1002 multibeam echosounder system (Swath bathymetry and seabed surveys of EEZ)

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, W.A.

    to either the transceiver unit or acquisition unit. The motion sensor along with the DGPS malfunctioning also affects the data. Apart from this the sound velocity value at transducer surface and within the water column plays an important role in ray... of acquisition. The EM1002 MBES system utilizes these offsets to steer the beams in the required direction. The file was created (by OEM) during the calibration survey and is utilized during beam-steering process so that the beam angle is adjusted for proper...

  17. Classroom

    Indian Academy of Sciences (India)

    Classroom" is equally a forum for raising broader issues and sharing personal ... published this paper as a short communication in the Cambridge and Dublin Mathematical Journal, in February 1854. Ray Optics and Mathematical Preliminaries.

  18. Inquiry-based instruction in secondary science classrooms: A survey of teacher practice

    Science.gov (United States)

    Gejda, Linda Muggeo

    The purpose of this quantitative investigation was to describe the extent to which secondary science teachers, who were certified through Connecticut's BEST portfolio assessment process between 1997 and 2004 and had taught secondary science during the past academic year, reported practicing the indicators of inquiry-based instruction in the classroom and the factors that they perceived facilitated, obstructed, or informed that practice. Indicators of inquiry-based instruction were derived from the Biological Sciences Curriculum Study (BSCS) 5E model (Bybee, 1997). The method for data collection was a researcher-developed, self-report, questionnaire entitled "Inquiry-based Instruction in Secondary Science Classrooms: A Survey", which was developed and disseminated using a slightly modified Dillman (2000) approach. Almost all of the study participants reported practicing the 5Es (engage, explore, explain, elaborate, and evaluate) of inquiry-based instruction in their secondary science classrooms. Time, resources, the need to cover material for mandatory assessments, the science topics or concepts being taught, and professional development on inquiry-based instruction were reported to be important considerations in participants' decisions to practice inquiry-based instruction in their science classrooms. A majority of the secondary science teachers participating in this study indicated they had the time, access to resources and the professional development opportunities they needed to practice inquiry-based instruction in their secondary classrooms. Study participants ranked having the time to teach in an inquiry-based fashion and the need to cover material for mandated testing as the biggest obstacles to their practice of inquiry-based instruction in the secondary classroom. Classroom experience and collegial exchange informed the inquiry-based instruction practice of the secondary science teachers who participated in this study. Recommendations for further research

  19. Classroom

    Indian Academy of Sciences (India)

    ias

    tum associated with such an apparently simple purely oscillatory 1D harmonic lattice system. The classroom exercise will conclude with a sug- gestion for the possibility that the 'Concrete' case may well correspond to that of hard nanopar- ticulate crystallites embedded in a 1D elastic con- tinuum, e.g., a spider dragline silk, ...

  20. Classroom

    Indian Academy of Sciences (India)

    CLASSROOM relate, for comparison, a school experience. There is an experi- ment in textbooks about measuring the percentage of oxygen in air. What the textbook prescribes is this: take a bowl with a little water, light a candle at the centre and then place an inverted glass over it. Soon the flame gets extinguished and ...

  1. Classroom

    Indian Academy of Sciences (India)

    sharing personal experiences and viewpoints on matters related to teaching and learning science. A W Joshil,. Umapati Pattar2 and F I Surve3. lDepartment of Physics ... Introduction. Diffraction from a plane grating is a familiar topic in undergraduate optics. Students study the theory in the classroom where they derive the ...

  2. Classroom

    Indian Academy of Sciences (India)

    "Classroom" is equally a forum for raising broader issues and sharing personal experiences and viewpoints on matters related ... sented the statement of the experimental problem of the. InternationalPhysics Olympiad'98 (IPhO). ... The justification of this model comes from electromagnetic theory. In conducting materials, the ...

  3. Classroom

    Indian Academy of Sciences (India)

    IAS Admin

    CLASSROOM. 655. RESONANCE | July 2016. References. [1]. C Alsina, R B Nelsen, Icons of Mathematics, The Mathematical Asso- ciation of America, Washington, DC, 2011. [2]. W Dunham, Journey through Genius, Penguin Books, 1991. which contradicts (2). So t = 0, i.e., 4r2. = a2. + b2 . Hence AB. 2. + AC. 2. = a2. + b2.

  4. Classroom

    Indian Academy of Sciences (India)

    Srimath

    In this section of Resonance, we invite readers to pose questions likely to be raised in a classroom situation. We may suggest strategies for dealing with them, or invite responses, ... weekends at the Bangalore. Association for Science Educa- tion, Jawaharlal Nehru Plan- etarium, Bangalore. Keywords. Planetary motion,.

  5. Classroom

    Indian Academy of Sciences (India)

    IAS Admin

    In this section of Resonance, we invite readers to pose questions likely to be raised in a classroom situation. We may suggest strategies for dealing with them, or invite responses, or both. “Classroom” is equally a forum for raising broader issues and sharing personal experiences and viewpoints on matters related to ...

  6. Classroom

    Indian Academy of Sciences (India)

    is, as evident from the normal meaning of the English word, a correspondence which associates to each mem ..... write it as a product of 3-cycles and go through the above analysis to actually arrive at a sequence of sliding moves which reaches the starting position. CLASSROOM. Look at the cycles. 0"1 = (1,2,. ,n,2n,. 2. 2. 1.

  7. Classroom

    Indian Academy of Sciences (India)

    Classroom" is equally a forum for raising broader issues ... then the business is subject to a stiff penalty of d per kg of shortage by the government if the business gets caught. (with probability p) in random checking; a meaningful value of d will be ...

  8. Classroom

    Indian Academy of Sciences (India)

    ite image of the Mercury. Transit, taken by Domin- ique Derrick, Belgium, on the 7th of May 2003. (repro- duced with permission). CLASSROOM scale in our understanding of the Universe - the Astronomical. Unit, or the mean distance between the Earth and the Sun. Historically, the transits of Venus were the first opportunity.

  9. Classroom

    Indian Academy of Sciences (India)

    CLASSROOM. Figure 3. An antibubble undergoing breakup, note the expanding circular hole at the bottom. Figure 4. An antibubble trapped in a vortex flow, just prior to breakup. of the antibubble into two smaller antibubbles (see Figure 4), an observation which is worthy of theoretical investigation. In the following video ...

  10. Classroom

    Indian Academy of Sciences (India)

    61. RESONANCE │ January 2011. CLASSROOM. Investigation of Structures Similarity of. Organic Substances. Keywords. Structures similarity, Tanimoto coefficient, Euclidean distance, fingerprints (bit-string represen- tations). Ajay Kumar. Guru Tegh Bahadur Institute of. Technology. G–8 Area, Rajouri Garden. New Delhi ...

  11. Classroom

    Indian Academy of Sciences (India)

    IAS Admin

    classroom situation. We may suggest strategies for dealing with them, or invite responses, or both. “Classroom” is equally a forum for raising broader issues and sharing personal experiences and viewpoints on matters related to teaching and learning science. Sheep Distribution Problem Through Egyptian Fractions.

  12. Artifacts and essentialism

    Science.gov (United States)

    Gelman, Susan A.

    2013-01-01

    Psychological essentialism is an intuitive folk belief positing that certain categories have a non-obvious inner “essence” that gives rise to observable features. Although this belief most commonly characterizes natural kind categories, I argue that psychological essentialism can also be extended in important ways to artifact concepts. Specifically, concepts of individual artifacts include the non-obvious feature of object history, which is evident when making judgments regarding authenticity and ownership. Classic examples include famous works of art (e.g., the Mona Lisa is authentic because of its provenance), but ordinary artifacts likewise receive value from their history (e.g., a worn and tattered blanket may have special value if it was one's childhood possession). Moreover, in some cases, object history may be thought to have causal effects on individual artifacts, much as an animal essence has causal effects. I review empirical support for these claims and consider the implications for both artifact concepts and essentialism. This perspective suggests that artifact concepts cannot be contained in a theoretical framework that focuses exclusively on similarity or even function. Furthermore, although there are significant differences between essentialism of natural kinds and essentialism of artifact individuals, the commonalities suggest that psychological essentialism may not derive from folk biology but instead may reflect more domain-general perspectives on the world. PMID:23976903

  13. Artifacts and essentialism.

    Science.gov (United States)

    Gelman, Susan A

    2013-09-01

    Psychological essentialism is an intuitive folk belief positing that certain categories have a non-obvious inner "essence" that gives rise to observable features. Although this belief most commonly characterizes natural kind categories, I argue that psychological essentialism can also be extended in important ways to artifact concepts. Specifically, concepts of individual artifacts include the non-obvious feature of object history, which is evident when making judgments regarding authenticity and ownership. Classic examples include famous works of art (e.g., the Mona Lisa is authentic because of its provenance), but ordinary artifacts likewise receive value from their history (e.g., a worn and tattered blanket may have special value if it was one's childhood possession). Moreover, in some cases, object history may be thought to have causal effects on individual artifacts, much as an animal essence has causal effects. I review empirical support for these claims and consider the implications for both artifact concepts and essentialism. This perspective suggests that artifact concepts cannot be contained in a theoretical framework that focuses exclusively on similarity or even function. Furthermore, although there are significant differences between essentialism of natural kinds and essentialism of artifact individuals, the commonalities suggest that psychological essentialism may not derive from folk biology but instead may reflect more domain-general perspectives on the world.

  14. Classroom

    Indian Academy of Sciences (India)

    Suggested Reading. [1] N Rathnasree and Sanath Kumart Preparing for the Transit of Venus,. Resonance, Vol. 9, No.3, pp.65-75, 2004. [2] G R Kaye, TheAstTcmomical Observatories ofJm Singh, Published by the. Archeological Survey ofIndia, 1910. [3] GSD BabuandV R Venu Gopal, Programme for the restoration of the.

  15. ASPECT: A Survey to Assess Student Perspective of Engagement in an Active-Learning Classroom.

    Science.gov (United States)

    Wiggins, Benjamin L; Eddy, Sarah L; Wener-Fligner, Leah; Freisem, Karen; Grunspan, Daniel Z; Theobald, Elli J; Timbrook, Jerry; Crowe, Alison J

    2017-01-01

    The primary measure used to determine relative effectiveness of in-class activities has been student performance on pre/posttests. However, in today's active-learning classrooms, learning is a social activity, requiring students to interact and learn from their peers. To develop effective active-learning exercises that engage students, it is important to gain a more holistic view of the student experience in an active-learning classroom. We have taken a mixed-methods approach to iteratively develop and validate a 16-item survey to measure multiple facets of the student experience during active-learning exercises. The instrument, which we call Assessing Student Perspective of Engagement in Class Tool (ASPECT), was administered to a large introductory biology class, and student responses were subjected to exploratory factor analysis. The 16 items loaded onto three factors that cumulatively explained 52% of the variation in student response: 1) value of activity, 2) personal effort, and 3) instructor contribution. ASPECT provides a rapid, easily administered means to measure student perception of engagement in an active-learning classroom. Gaining a better understanding of students' level of engagement will help inform instructor best practices and provide an additional measure for comprehensively assessing the impact of different active-learning strategies. © 2017 B. L. Wiggins, S. L. Eddy, et al. CBE—Life Sciences Education © 2017 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  16. A survey of acoustic conditions and noise levels in secondary school classrooms in England.

    Science.gov (United States)

    Shield, Bridget; Conetta, Robert; Dockrell, Julie; Connolly, Daniel; Cox, Trevor; Mydlarz, Charles

    2015-01-01

    An acoustic survey of secondary schools in England has been undertaken. Room acoustic parameters and background noise levels were measured in 185 unoccupied spaces in 13 schools to provide information on the typical acoustic environment of secondary schools. The unoccupied acoustic and noise data were correlated with various physical characteristics of the spaces. Room height and the amount of glazing were related to the unoccupied reverberation time and therefore need to be controlled to reduce reverberation to suitable levels for teaching and learning. Further analysis of the unoccupied data showed that the introduction of legislation relating to school acoustics in England and Wales in 2003 approximately doubled the number of school spaces complying with current standards. Noise levels were also measured during 274 lessons to examine typical levels generated during teaching activities in secondary schools and to investigate the influence of acoustic design on working noise levels in the classroom. Comparison of unoccupied and occupied data showed that unoccupied acoustic conditions affect the noise levels occurring during lessons. They were also related to the time spent in disruption to the lessons (e.g., students talking or shouting) and so may also have an impact upon student behavior in the classroom.

  17. Technology Use and Acceptance in the Classroom: Results from an Exploratory Survey Study among Secondary Education Teachers in the USA

    Science.gov (United States)

    Holden, Heather; Ozok, Ant; Rada, Roy

    2008-01-01

    Purpose: The purpose of this study is to explore the current usage and acceptance of classroom technologies by secondary math/science education teachers in one community. Design/methodology/approach: Forty-seven secondary education math and science teachers in one American city responded to a survey about their use and perceptions of technology in…

  18. Preservice Teachers' Classroom Management Training: A Survey of Self-Reported Training Experiences, Content Coverage, and Preparedness

    Science.gov (United States)

    Christofferson, Michael; Sullivan, Amanda L.

    2015-01-01

    Many teachers report that their preservice training in classroom management was inadequate or ineffective, but little is known about the types of training they receive. In this exploratory study, 157 preservice teachers from throughout the United States were surveyed about the training sources through which they obtained knowledge and skills in…

  19. A Survey of Exemplar Teachers' Perceptions, Use, and Access of Computer-Based Games and Technology for Classroom Instruction

    Science.gov (United States)

    Proctor, Michael D.; Marks, Yaela

    2013-01-01

    This research reports and analyzes for archival purposes surveyed perceptions, use, and access by 259 United States based exemplar Primary and Secondary educators of computer-based games and technology for classroom instruction. Participating respondents were considered exemplary as they each won the Milken Educator Award during the 1996-2009…

  20. Flipped Classrooms in Graduate Medical Education: A National Survey of Residency Program Directors.

    Science.gov (United States)

    Wittich, Christopher M; Agrawal, Anoop; Wang, Amy T; Halvorsen, Andrew J; Mandrekar, Jayawant N; Chaudhry, Saima; Dupras, Denise M; Oxentenko, Amy S; Beckman, Thomas J

    2017-06-20

    To begin to quantify and understand the use of the flipped classroom (FC)-a progressive, effective, curricular model-in internal medicine (IM) education in relation to residency program and program director (PD) characteristics. The authors conducted a survey that included the Flipped Classroom Perception Instrument (FCPI) in 2015 regarding programs' use and PDs' perceptions of the FC model. Among the 368 IM residency programs, PDs at 227 (61.7%) responded to the survey and 206 (56.0%) completed the FCPI. Regarding how often programs used the FC model, 34 of the 206 PDs (16.5%) reported "never"; 44 (21.4%) reported "very rarely"; another 44 (21.4%) reported "somewhat rarely"; 59 (28.6%) reported "sometimes"; 16 (7.8%) reported "somewhat often"; and 9 (4.4%) reported "very often." The mean FCPI score (standard deviation [SD]) for the in-class application factor (4.11 [0.68]) was higher (i.e., more favorable) than for the preclass activity factor (3.94 [0.65]) (P 50 years, 3.94 [0.61]; P = .04) and women compared with men (4.28 [0.56] vs. 3.91 [0.62]; P < .001). PDs with better perceptions of FCs had higher odds of using FCs (odds ratio, 4.768; P < .001). Most IM programs use the FC model at least to some extent, and PDs prefer the interactive in-class components over the independent preclass activities. PDs who are women and younger perceived the model more favorably.

  1. Perceived-Target-Language-Use Survey in the English Classrooms in China: Investigation of Classroom-Related and Institutional Factors

    Science.gov (United States)

    Yan, Edith M. Y.; Fung, Irene Y. Y.; Liu, Lili; Huang, Xiaoyan

    2016-01-01

    This quantitative study investigated the extent and contexts of target language (TL) use in English language classrooms. Participants were 2,906 students from seven secondary schools and four universities in the more developed cities in southern China. They were put into five groups according to their educational stage and whether their content…

  2. The Information Systems Artifact

    DEFF Research Database (Denmark)

    Chatterjee, Surtirtha; Xiao, Xiao; Elbanna, Amany

    2017-01-01

    Passionate debates regarding the defining characteristic of the “IT artifact” continue. Such debates, and also the lack of explicit consideration of the “information” element in the IT artifact, motivate us to propose a revised conception, drawing upon concepts from General Systems Theory (GST...

  3. Detection and removal of artifacts in astronomical images

    Science.gov (United States)

    Desai, S.; Mohr, J. J.; Bertin, E.; Kümmel, M.; Wetzstein, M.

    2016-07-01

    Astronomical images from optical photometric surveys are typically contaminated with transient artifacts such as cosmic rays, satellite trails and scattered light. We have developed and tested an algorithm that removes these artifacts using a deep, artifact free, static sky coadd image built up through the median combination of point spread function (PSF) homogenized, overlapping single epoch images. Transient artifacts are detected and masked in each single epoch image through comparison with an artifact free, PSF-matched simulated image that is constructed using the PSF-corrected, model fitting catalog from the artifact free coadd image together with the position variable PSF model of the single epoch image. This approach works well not only for cleaning single epoch images with worse seeing than the PSF homogenized coadd, but also the traditionally much more challenging problem of cleaning single epoch images with better seeing. In addition to masking transient artifacts, we have developed an interpolation approach that uses the local PSF and performs well in removing artifacts whose widths are smaller than the PSF full width at half maximum, including cosmic rays, the peaks of saturated stars and bleed trails. We have tested this algorithm on Dark Energy Survey Science Verification data and present performance metrics. More generally, our algorithm can be applied to any survey which images the same part of the sky multiple times.

  4. The Human-Artifact Model

    DEFF Research Database (Denmark)

    Bødker, Susanne; Klokmose, Clemens Nylandsted

    2011-01-01

    needs to support such development through concepts and methods. This leads to a methodological approach that focuses on new artifacts to supplement and substitute existing artifacts. Through a design case, we develop the methodological approach and illustrate how the human–artifact model can be applied...... to analyze present artifacts and to design future ones. The model is used to structure such analysis and to reason about findings while providing leverage from activity theoretical insights on mediation, dialectics, and levels of activity....

  5. Examining Student Digital Artifacts during a Year-Long Technology Integration Initiative

    Science.gov (United States)

    Rodriguez, Prisca M.; Frey, Chris; Dawson, Kara; Liu, Feng; Ritzhaupt, Albert D.

    2012-01-01

    This study was situated within a year-long, statewide technology integration initiative designed to support technology integration within science, technology, engineering, and math classrooms. It examined the elements used in student artifacts in an attempt to investigate trends in digital artifact creation. Among several conclusions, this…

  6. Small Artifacts - Big Technologies

    DEFF Research Database (Denmark)

    Kreiner, Kristian

    2005-01-01

    The computer IC is the heart of the information and telecommunication technology. It is a tiny artifact, but with incredible organizing powers. We use this physical artifact as the location for studying central problems of the knowledge economy. First, the paper describes the history of chip design...... and the emergence of the technological community involved in designing and manufacturing computer chips. The community is structured in a way that reflects the underlying physical nature silicon and the numerous other materials and chemicals involved. But it also reflects the human agency of defining new projects......, of visioning the liberation from atoms, of committing to travel many detours in the labyrinths of development, and of perceiving and exploring the affordance that new technologies hide. Some of these characteristics are analyzed empirically in a case study of designing a chip for a digitalized hearing...

  7. Classroom Listening Conditions in Indian Primary Schools: A Survey of Four Schools.

    Science.gov (United States)

    Sundaravadhanan, Gayathri; Selvarajan, Heramba G; McPherson, Bradley

    2017-01-01

    Background noise affects the listening environment inside classrooms, especially for younger children. High background noise level adversely affects not only student speech perception but also teacher vocal hygiene. The current study aimed to give an overview of the classroom listening conditions in selected government primary schools in India. Noise measurements were taken in 23 classrooms of four government primary schools in southern India, using a type 2 sound level meter. In each classroom measurements were taken in occupied and unoccupied conditions. Teacher voice level was measured in the same classrooms. In addition, the classroom acoustical conditions were observed and the reverberation time for each classroom was calculated. The mean occupied noise level was 62.1 dBA and 65.6 dBC, and the mean unoccupied level was 62.2 dBA and 65 dBC. The mean unamplified teacher speech-to-noise ratio was 10.6 dBA. Both the occupied and unoccupied noise levels exceeded national and international recommended levels and the teacher speech-to-noise ratio was also found to be inadequate in most classrooms. The estimated reverberation time in all classrooms was greater than 2.6 seconds, which is almost double the duration of accepted standards. In addition, observation of classrooms revealed insufficient acoustical treatment to effectively reduce internal and external noise and minimize reverberation. The results of this study point out the need to improve the listening environment for children in government primary schools in India.

  8. An Additive Manufacturing Test Artifact

    Science.gov (United States)

    Moylan, Shawn; Slotwinski, John; Cooke, April; Jurrens, Kevin; Donmez, M Alkan

    2014-01-01

    A test artifact, intended for standardization, is proposed for the purpose of evaluating the performance of additive manufacturing (AM) systems. A thorough analysis of previously proposed AM test artifacts as well as experience with machining test artifacts have inspired the design of the proposed test artifact. This new artifact is designed to provide a characterization of the capabilities and limitations of an AM system, as well as to allow system improvement by linking specific errors measured in the test artifact to specific sources in the AM system. The proposed test artifact has been built in multiple materials using multiple AM technologies. The results of several of the builds are discussed, demonstrating how the measurement results can be used to characterize and improve a specific AM system. PMID:26601039

  9. An Additive Manufacturing Test Artifact.

    Science.gov (United States)

    Moylan, Shawn; Slotwinski, John; Cooke, April; Jurrens, Kevin; Donmez, M Alkan

    2014-01-01

    A test artifact, intended for standardization, is proposed for the purpose of evaluating the performance of additive manufacturing (AM) systems. A thorough analysis of previously proposed AM test artifacts as well as experience with machining test artifacts have inspired the design of the proposed test artifact. This new artifact is designed to provide a characterization of the capabilities and limitations of an AM system, as well as to allow system improvement by linking specific errors measured in the test artifact to specific sources in the AM system. The proposed test artifact has been built in multiple materials using multiple AM technologies. The results of several of the builds are discussed, demonstrating how the measurement results can be used to characterize and improve a specific AM system.

  10. Deciphering open space in urban contexts: Geophysical survey, soil multi-element chemical analysis, and artifact distributions at the 15th–16th-century AD Swahili settlement of Songo Mnara

    DEFF Research Database (Denmark)

    Fleisher, Jeffrey; Sulas, Federica

    2015-01-01

    Open spaces are an integral part of past urban settlement worldwide. Often large and devoid of visible traces of past activities, these spaces challenge mainstream archaeological approaches to develop methodologies suitable to investigate their history. This study uses geophysical survey, geochem......Open spaces are an integral part of past urban settlement worldwide. Often large and devoid of visible traces of past activities, these spaces challenge mainstream archaeological approaches to develop methodologies suitable to investigate their history. This study uses geophysical survey......, geochemical sampling and artifact distributions to examine open spaces at the Swahili stonetown of Songo Mnara, Tanzania. Initial, magnetic susceptibility survey revealed a set of anomalies associated with activities across the open spaces at the site; a systematic soil/sediment sampling program was applied...... fragmented ceramics and other chemical elements (Ca, Na, Mg, Sr). The integrated methodological framework developed at Songo Mnara offers a new way to define areas that may have functioned as ‘public spaces’ as well as possible activities that were carried out in them. The results suggest that open spaces...

  11. Factors of Code Switching among Bilingual English Students in the University Classroom: A Survey

    Science.gov (United States)

    Bista, Krishna

    2010-01-01

    This study proposes to identify and evaluate the factors that affect code switching in the university classroom among 15 bilingual international students. The findings from the study conducted in a southern American university revealed that the primary factor of code switching in international classroom is incompetence in the second language.…

  12. Classroom Listening Conditions in Indian Primary Schools: A Survey of Four Schools

    Directory of Open Access Journals (Sweden)

    Gayathri Sundaravadhanan

    2017-01-01

    Full Text Available Introduction: Background noise affects the listening environment inside classrooms, especially for younger children. High background noise level adversely affects not only student speech perception but also teacher vocal hygiene. The current study aimed to give an overview of the classroom listening conditions in selected government primary schools in India. Materials and Methods: Noise measurements were taken in 23 classrooms of four government primary schools in southern India, using a type 2 sound level meter. In each classroom measurements were taken in occupied and unoccupied conditions. Teacher voice level was measured in the same classrooms. In addition, the classroom acoustical conditions were observed and the reverberation time for each classroom was calculated. Results: The mean occupied noise level was 62.1 dBA and 65.6 dBC, and the mean unoccupied level was 62.2 dBA and 65 dBC. The mean unamplified teacher speech-to-noise ratio was 10.6 dBA. Both the occupied and unoccupied noise levels exceeded national and international recommended levels and the teacher speech-to-noise ratio was also found to be inadequate in most classrooms. The estimated reverberation time in all classrooms was greater than 2.6 seconds, which is almost double the duration of accepted standards. In addition, observation of classrooms revealed insufficient acoustical treatment to effectively reduce internal and external noise and minimize reverberation. Conclusion: The results of this study point out the need to improve the listening environment for children in government primary schools in India.

  13. From Ecological Sounding Artifacts Towards Sonic Artifact Ecologies

    DEFF Research Database (Denmark)

    Erkut, Cumhur; Serafin, Stefania

    2016-01-01

    The discipline of sonic interaction design has been focused on the interaction between a single user and an artifact. This strongly limits one of the fundamental aspects of music as a social and interactive experience. In this paper we propose sonic artifact ecologies as a mean to examine...

  14. Sound as artifact

    Science.gov (United States)

    Benjamin, Jeffrey L.

    A distinguishing feature of the discipline of archaeology is its reliance upon sensory dependant investigation. As perceived by all of the senses, the felt environment is a unique area of archaeological knowledge. It is generally accepted that the emergence of industrial processes in the recent past has been accompanied by unprecedented sonic extremes. The work of environmental historians has provided ample evidence that the introduction of much of this unwanted sound, or "noise" was an area of contestation. More recent research in the history of sound has called for more nuanced distinctions than the noisy/quiet dichotomy. Acoustic archaeology tends to focus upon a reconstruction of sound producing instruments and spaces with a primary goal of ascertaining intentionality. Most archaeoacoustic research is focused on learning more about the sonic world of people within prehistoric timeframes while some research has been done on historic sites. In this thesis, by way of a meditation on industrial sound and the physical remains of the Quincy Mining Company blacksmith shop (Hancock, MI) in particular, I argue for an acceptance and inclusion of sound as artifact in and of itself. I am introducing the concept of an individual sound-form, or sonifact , as a reproducible, repeatable, representable physical entity, created by tangible, perhaps even visible, host-artifacts. A sonifact is a sound that endures through time, with negligible variability. Through the piecing together of historical and archaeological evidence, in this thesis I present a plausible sonifactual assemblage at the blacksmith shop in April 1916 as it may have been experienced by an individual traversing the vicinity on foot: an 'historic soundwalk.' The sensory apprehension of abandoned industrial sites is multi-faceted. In this thesis I hope to make the case for an acceptance of sound as a primary heritage value when thinking about the industrial past, and also for an increased awareness and acceptance

  15. Building-related health symptoms and classroom indoor air quality: a survey of school teachers in New York State.

    Science.gov (United States)

    Kielb, C; Lin, S; Muscatiello, N; Hord, W; Rogers-Harrington, J; Healy, J

    2015-08-01

    Most previous research on indoor environments and health has studied school children or occupants in non-school settings. This investigation assessed building-related health symptoms and classroom characteristics via telephone survey of New York State school teachers. Participants were asked about 14 building-related symptoms and 23 classroom characteristics potentially related to poor indoor air quality (IAQ). Poisson regression analysis was used to assess the relationship between these symptoms and each classroom characteristic, controlling for potential confounders. About 500 teachers completed the survey. The most frequently reported classroom characteristics included open shelving (70.7%), food eaten in class (65.5%), dust (59.1%), and carpeting (46.9%). The most commonly reported symptoms included sinus problems (16.8%), headache (15.0%), allergies/congestion (14.8%), and throat irritation (14.6%). Experiencing one or more symptoms was associated most strongly with reported dust (relative risk (RR) = 3.67; 95% confidence interval (CI): 2.62-5.13), dust reservoirs (RR = 2.13; 95% CI: 1.72-2.65), paint odors (RR = 1.73; 95% CI: 1.40-2.13), mold (RR = 1.71; 95% CI: 1.39-2.11), and moldy odors (RR = 1.65 95% CI: 1.30-2.10). Stronger associations were found with increasing numbers of reported IAQ-related classroom characteristics. Similar results were found with having any building-related allergic/respiratory symptom. This research adds to the body of evidence underscoring the importance to occupant health of school IAQ. Teachers play an important role in educating children, and teacher well-being is important to this role. Health symptoms among New York teachers while at work are common and appear to be associated with numerous characteristics related to poor classroom IAQ. Improving school Indoor Air Quality may reduce sickness and absenteeism and improve teacher performance. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Turquoise Artifact from Teotihuacan

    Energy Technology Data Exchange (ETDEWEB)

    Spence, Michael W.; Harbottle, Garman; Weigand, Phil C.

    1999-07-01

    Turquoise artifacts appeared sporadically in Mesoamerica as early as the Formative period (Merry de Morales 1987:100, Figure 8.4; Weigand 1989:43). Most occurrences, however, postdate the collapse of Teotihuacan. In the Late Classic and Postclassic periods increasing quantities are found, often in the form of elaborate mosaics, in a wide variety of contexts in central, west and northwest Mexico. Neutron activation analysis has determined that much of this turquoise derives from sources in the southwestern United States (Weigand et al. 1977; Harbottle and Weigand 1992; Weigand and Harbottle 1993). Teotihuacan played a major role in Mesoamerica during the Terminal Formative and Early-Middle Classic periods. It was the dominant power in central Mexico from about the time of Christ to its collapse at about A.D. 650 (Millon 1988, 1992; Cowgill 1996). Throughout this period goods flowed into Teotihuacan from many parts of the Mesoamerican world. Despite this widespread economic interaction, only two pieces of turquoise have been recovered in the city. In the following pages, the context and implications of one of these finds will be examined.

  17. Investigating media artifacts with children

    DEFF Research Database (Denmark)

    Chimirri, Niklas Alexander

    developments are rooted in the author’s participation in a daycare practice in Berlin, Germany. The daycare’s situational approach precisely attempted to draw on the children’s everyday life experiences so as to engage in problem-oriented learning projects, on media artifacts and beyond.......The dissertation’s aim is to explore the everyday relevance media artifacts have for young children. It discusses and further develops analytical concepts that are committed to taking the children’s perspectives on possibilities and limitations of such artifacts seriously. These conceptual...

  18. Diversity and Inclusion of Sociopolitical Issues in Foreign Language Classrooms: An Exploratory Survey.

    Science.gov (United States)

    Kubota, Ryuko; Austin, Theresa; Saito-Abbott, Yoshiko

    2003-01-01

    Investigated diversity in the classroom, student background and learning experiences, and perceptions about the relationship between foreign language learning and issues of race, gender, class, and social justice among university students studying Spanish, Japanese, and Swahili. Found more racial diversity in Japanese and Swahili classes and in…

  19. ASPECT: A Survey to Assess Student Perspective of Engagement in an Active-Learning Classroom

    Science.gov (United States)

    Wiggins, Benjamin L.; Eddy, Sarah L.; Wener-Fligner, Leah; Freisem, Karen; Grunspan, Daniel Z.; Theobald, Elli J.; Timbrook, Jerry; Crowe, Alison J.

    2017-01-01

    The primary measure used to determine relative effectiveness of in-class activities has been student performance on pre/posttests. However, in today's active-learning classrooms, learning is a social activity, requiring students to interact and learn from their peers. To develop effective active-learning exercises that engage students, it is…

  20. A Survey of Graduate Social Work Educators: Teaching Perspectives and Classroom Environments

    Science.gov (United States)

    Danhoff, Kristin Lindsay

    2012-01-01

    Social work educators have the challenging task of preparing students to be ethically, morally, and socially responsible professionals. As professionals in the 21st Century, social workers are faced with ever increasing complexity and change. Teaching philosophies are at the foundation of what educators do in the classroom. Research about teaching…

  1. The Supervision of Information Technology Classrooms in Turkey: A Nationwide Survey

    Science.gov (United States)

    Memisoglu, Salih Pasa

    2007-01-01

    The purpose of this study was to identify how primary school supervisors carry out their roles concerning information and communications technology (ICT) based classrooms in public primary schools in Turkey. Data were collected via a questionnaire from 583 primary school supervisors working in 17 different provinces. Statistical programs were used…

  2. JPEG ringing artifact visibility evaluation

    Science.gov (United States)

    Hu, Sirui; Pizlo, Zygmunt; Allebach, Jan P.

    2014-01-01

    To achieve high perceptual quality of compressed images, many objective image quality metrics for compression artifacts evaluation and reduction have been developed based on characterization of local image features. However, it is the end user who is judging the image quality in various applications, so the validation of how well these metrics predict human perception is important and necessary. In this paper, we present a preliminary psychophysics experiment method to capture human perception of local ringing artifacts in JPEG images with different severity levels. Observers are asked to annotate the compressed image where they perceive artifacts along the edges, directly on the screen using an interactive tablet display. They are asked to catalog the severity of artifacts into one of the three levels: Strong, Medium, and Light. We process the hand-marked data into a ringing visibility edge map showing a ringing severity mean opinion score (MOS) at every edge pixel. The perceptual information captured in this experiment, enables us to study the correlation between human perception and local image features, which is an important step towards the goal of developing a non-reference (NR) objective metric to predict the visibility of JPEG ringing artifacts in alignment with the assessments of human observers.

  3. Evaluation of Audio Compression Artifacts

    Directory of Open Access Journals (Sweden)

    M. Herrera Martinez

    2007-01-01

    Full Text Available This paper deals with subjective evaluation of audio-coding systems. From this evaluation, it is found that, depending on the type of signal and the algorithm of the audio-coding system, different types of audible errors arise. These errors are called coding artifacts. Although three kinds of artifacts are perceivable in the auditory domain, the author proposes that in the coding domain there is only one common cause for the appearance of the artifact, inefficient tracking of transient-stochastic signals. For this purpose, state-of-the art audio coding systems use a wide range of signal processing techniques, including application of the wavelet transform, which is described here. 

  4. A Survey of Attitudes on the Use of Calculators in the College Classroom.

    Science.gov (United States)

    Bukowski, Joseph E.

    This study focused on faculty and student attitudes toward the use of calculators in college accounting and business mathematics courses. Two different surveys were used; one was administered to thirty-five full-time and part-time faculty in the accounting and business mathematics areas at one college, while a second survey was administered to a…

  5. Autism Treatment Survey: Services Received by Children with Autism Spectrum Disorders in Public School Classrooms

    Science.gov (United States)

    Hess, Kristen L.; Morrier, Michael J.; Heflin, L.; Ivey, Michelle L.

    2008-01-01

    The Autism Treatment Survey was developed to identify strategies used in education of children with autism spectrum disorders (ASD) in Georgia. Respondents of the web-based survey included a representative sample of 185 teachers across the state, reporting on 226 children with ASD in grades preschool-12th. The top five strategies being used in…

  6. On the Capabilities of Digimaterial Artifacts

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    The purpose of the paper is to propose and discuss three types of capabilities of digimaterial artifacts like laptop computers, cameras, cars, robots etc. Digimaterial artifacts are material artifacts that combine digital and non-digital elements by bearing one or more digital artifacts. Digital...... artifacts are linguistic expressions like, say, binary sequences of 0's and 1's. Software and databases are examples of digital artifacts. Paper pieces with digital inscriptions and cars with data and software are examples of digimaterial artifacts. Digimaterial artifacts can bear, and potentially...... manipulate, digital artifacts. We describe and discuss digimaterial structures and the capabilities that are enabled by these structures. And we describe and discuss the plastic nature of such structures and capabilities. We expect that our work can be used to understand digimaterial capabilities...

  7. Third and Fourth Grade Teacher's Classroom Practices in Writing: A National Survey

    Science.gov (United States)

    Brindle, Mary; Graham, Steve; Harris, Karen R.; Hebert, Michael

    2016-01-01

    A random sample of teachers in grades 3 and 4 (N = 157) from across the United States were surveyed about their use of evidence-based writing practices, preparation to teach writing, and beliefs about writing. Teachers' beliefs included their efficacy to teach writing, their orientations to teach writing, their attitude about teaching writing, and…

  8. Artifacts as Authoritative Actors in Educational Reform

    Science.gov (United States)

    März, Virginie; Kelchtermans, Geert; Vermeir, Karen

    2017-01-01

    Educational reforms are often translated in and implemented through artifacts. Although research has frequently treated artifacts as merely functional, more recent work acknowledges the complex relationship between material artifacts and human/organizational behavior. This article aims at disentangling this relationship in order to deepen our…

  9. Automatic Artifact Removal from Electroencephalogram Data Based on A Priori Artifact Information

    Directory of Open Access Journals (Sweden)

    Chi Zhang

    2015-01-01

    Full Text Available Electroencephalogram (EEG is susceptible to various nonneural physiological artifacts. Automatic artifact removal from EEG data remains a key challenge for extracting relevant information from brain activities. To adapt to variable subjects and EEG acquisition environments, this paper presents an automatic online artifact removal method based on a priori artifact information. The combination of discrete wavelet transform and independent component analysis (ICA, wavelet-ICA, was utilized to separate artifact components. The artifact components were then automatically identified using a priori artifact information, which was acquired in advance. Subsequently, signal reconstruction without artifact components was performed to obtain artifact-free signals. The results showed that, using this automatic online artifact removal method, there were statistical significant improvements of the classification accuracies in both two experiments, namely, motor imagery and emotion recognition.

  10. Artifact

    DEFF Research Database (Denmark)

    2014-01-01

    uses a conceptual form of art, it means that all the planning and decisions are made beforehand and the execution is a perfunctory affair. The idea becomes a machine that makes art.’ (Sol LeWitt, ‘Paragraph on Conceptual art’, in Artforum, 1967.)We would like to draw on Sol LeWitt’s vision and then we...

  11. Use of cognitive artifacts in chemistry learning

    Science.gov (United States)

    Yengin, Ilker

    In everyday life, we interact with cognitive artifacts to receive and/or manipulate information so as to alter our thinking processes. CHEM/TEAC 869Q is a distance course that includes extensive explicit instruction in the use of a cognitive artifact. This study investigates issues related to the design of that online artifact. In order to understand design implications and how cognitive artifacts contribute to students' thinking and learning, a qualitative research methodology was engaged that utilized think aloud sessions. Participants' described constrained and structured cognitive models while using the artifact. The study also was informed by interviews and researcher's field notes. A purposeful sampling method led to the selection of participants, four males and two females, who had no prior history of using a course from the 869 series but who had experienced the scientific content covered by the CHEM869Q course. Analysis of the results showed both that a cognitive artifact may lead users' minds in decision making, and that problem solving processes were affected by cognitive artifact's design. When there is no design flaw, users generally thought that the cognitive artifact was helpful by simplifying steps, overcoming other limitations, and reducing errors in a reliable, effective, and easy to use way. Moreover, results showed that successful implementation of cognitive artifacts into teaching --learning practices depended on user willingness to transfer a task to the artifact. While users may like the idea of benefiting from a cognitive artifact, nevertheless, they may tend to limit their usage. They sometimes think that delegating a task to a cognitive artifact makes them dependent, and that they may not learn how to perform the tasks by themselves. They appear more willing to use a cognitive artifact after they have done the task by themselves.

  12. An EEG Data Investigation Using Only Artifacts

    Science.gov (United States)

    2017-02-22

    EEG Data Investigation Using Only Artifacts 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 1 Chelsey...and Education – Belcamp, MD 3 Middendorf Scientific Services – Medway, Ohio 45341 4 Air Force Research Laboratory – 2510 Fifth Street Bldg 840, Wright... investigation uses only data contaminated by artifacts and discards the artifact free data. This was done to solve a problem associated with data collection

  13. A STUDY OF CODE SWITCHING AND CODE MIXING IN EFL CLASSROOM: A SURVEY OF CLASSROOM INTERACTION AT ENGLISH EDUCATION STUDY PROGRAM OF UIN RADEN FATAH PALEMBANG

    Directory of Open Access Journals (Sweden)

    Annisa Astrid

    2017-04-01

    Full Text Available The Study was conducted in oder to find out a phenomena of code switching and code mixing happened in EFL classrom. The writer collected the data from English Education Study Program of UIN Raden Fatah Palembang. Four classes were observed to have the phenomena of code switching and code mixing. A set of questionnaire was given to 120 students and 15 lecturers of English in order to assess their attitude and feedback toward the use of code switching and code mixing. The Results of the research study showed that the lecturers and the students employed code switching and code mixing in the interactions which happened along teaching and learning activities with various patterns and considerations. Finally the data from the questionnaire reflects the positive attitude toward the use of code switching and code mixing along teaching and learning activities in the classroom.

  14. Computed Tomographic Artifacts in Maxillofacial Surgery.

    Science.gov (United States)

    Kim, Jun Ho; Arita, Emiko Saito; Pinheiro, Lucas Rodrigues; Yoshimoto, Marcelo; Watanabe, Plauto Christopher Aranha; Cortes, Arthur Rodriguez Gonzalez

    2018-01-01

    The present study aimed to present 4 cases and to undertake a systematic review on the current knowledge of the impact of cone beam computed tomographic (CBCT) artifacts on oral and maxillofacial surgical planning and follow-up. The MEDLINE (PubMed) database was searched for the period from February 2004 to February 2017, for studies on the impact of CBCT artifacts on surgical planning of oral and maxillofacial surgeries. The PRISMA statement was followed during data assessment and extraction. As a result, data extraction included information regarding: the use of CBCT to plan or follow-up oral and maxillofacial surgeries, presence and type identification of a CBCT artifact, and details on the impact of artifacts on image quality and/or surgical planning. Four cases were selected to illustrate the topic. The search strategy yielded 408 publications in MEDLINE (PubMed). An initial screening of the publications was performed using abstracts and key words. After application of exclusion criteria, a total of 11 studies were finally identified as eligible to be discussed. Studies revealed 3 main types of artifact: beam hardening, streak, and motion artifacts. Most of the studies suggest that artifacts significantly affect oral and maxillofacial surgical planning and follow-up, despite of allowing for identification of metal projectiles in cases of maxillofacial trauma. CBCT artifacts have a significant impact on oral and maxillofacial surgical planning and follow-up.

  15. The Ambivalent Ontology of Digital Artifacts

    DEFF Research Database (Denmark)

    Kallinikos, Jannis; Aaltonen, Aleksi; Marton, Attila

    2013-01-01

    of functional relations with other artifacts across specific contexts and organizations. By the same token, it apportions control over the development and use of these artifacts over a range of dispersed stakeholders and makes their management a complex technical and social undertaking. These ideas...

  16. Conceptual Model of Artifacts for Design Science Research

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    2015-01-01

    We present a conceptual model of design science research artifacts. The model views an artifact at three levels. At the artifact level a selected artifact is viewed as a combination of material and immaterial aspects and a set of representations hereof. At the design level the selected artifact...

  17. Silicon bulk micromachined hybrid dimensional artifact.

    Energy Technology Data Exchange (ETDEWEB)

    Claudet, Andre A.; Tran, Hy D.; Bauer, Todd Marks; Shilling, Katherine Meghan; Oliver, Andrew David

    2010-03-01

    A mesoscale dimensional artifact based on silicon bulk micromachining fabrication has been developed and manufactured with the intention of evaluating the artifact both on a high precision coordinate measuring machine (CMM) and video-probe based measuring systems. This hybrid artifact has features that can be located by both a touch probe and a video probe system with a k=2 uncertainty of 0.4 {micro}m, more than twice as good as a glass reference artifact. We also present evidence that this uncertainty could be lowered to as little as 50 nm (k=2). While video-probe based systems are commonly used to inspect mesoscale mechanical components, a video-probe system's certified accuracy is generally much worse than its repeatability. To solve this problem, an artifact has been developed which can be calibrated using a commercially available high-accuracy tactile system and then be used to calibrate typical production vision-based measurement systems. This allows for error mapping to a higher degree of accuracy than is possible with a glass reference artifact. Details of the designed features and manufacturing process of the hybrid dimensional artifact are given and a comparison of the designed features to the measured features of the manufactured artifact is presented and discussed. Measurement results from vision and touch probe systems are compared and evaluated to determine the capability of the manufactured artifact to serve as a calibration tool for video-probe systems. An uncertainty analysis for calibration of the artifact using a CMM is presented.

  18. A particle accelerator probes artifacts

    CERN Document Server

    Dran, J C; Salomon, J

    2002-01-01

    The AGLAE system is made up of a 2 mega volts electrostatic accelerator and of 3 irradiation lines: one leads to a vacuum enclosure in which targets are irradiated and the 2 others lines are designed to irradiate targets under an air or helium atmosphere. The AGLAE system is located in the premises of the Louvre museum in Paris and is devoted to the study of cultural objects through ion beam analysis (IBA). 4 techniques are used: -) proton-induced X-ray emission (PIXE) -) proton-induced gamma ray (PIGE) -) Rutherford backscattering spectrometry (NRS) and -) nuclear reaction analysis (NRA). A decisive progress has permitted the direct analysis of artifacts without sampling. The object itself is set just a few millimeters away from the exit window of the beam in an air or helium atmosphere. The exit window must be resistant enough to bear the atmospheric pressure and the damages caused by the proton beam but must be thin enough to not deteriorate the quality of the beam. By using a 10 sup - sup 7 m thick exit w...

  19. Flipping the History Classroom with an Embedded Writing Consultant: Synthesizing Inverted and WAC Paradigms in a University History Survey Course

    Science.gov (United States)

    Murphree, Daniel

    2015-01-01

    "Flipping" the Classroom techniques and the use of Embedded Writing Consultants (EWC) in institutions of higher education have been the subject of scholarly research in recent years. However, it appears that no studies have examined the simultaneous use of both "tools" in an introductory History course at the university level.…

  20. Preschool Teachers' Use of Music in the Classroom: A Survey of Park District Preschool Programs

    Science.gov (United States)

    Rajan, Rekha S.

    2017-01-01

    The purpose of this study was to explore how preschool teachers use music and identify the types of music activities available to children in their classrooms. Preschool teachers (N = 178) at park district programs throughout a large state in the American Midwest responded to an online questionnaire. Although teachers acknowledged using music…

  1. Placement of Twins and Multiples in the Classroom: A Brief Survey of School Counselors' Knowledge and Attitudes

    Science.gov (United States)

    Nilsson, Johanna; Leonard, Lynn; Barazanji, Danah; Simone, Rachel

    2010-01-01

    This study investigated 65 school counselors' perception of classroom placement of twins and multiples. The results show that most of the participants had twins and multiples in their schools, but that they were neither aware of their school district nor building's policy regarding placement. Most participants supported early separation, already…

  2. Automatic Identification of Artifact-Related Independent Components for Artifact Removal in EEG Recordings.

    Science.gov (United States)

    Zou, Yuan; Nathan, Viswam; Jafari, Roozbeh

    2016-01-01

    Electroencephalography (EEG) is the recording of electrical activity produced by the firing of neurons within the brain. These activities can be decoded by signal processing techniques. However, EEG recordings are always contaminated with artifacts which hinder the decoding process. Therefore, identifying and removing artifacts is an important step. Researchers often clean EEG recordings with assistance from independent component analysis (ICA), since it can decompose EEG recordings into a number of artifact-related and event-related potential (ERP)-related independent components. However, existing ICA-based artifact identification strategies mostly restrict themselves to a subset of artifacts, e.g., identifying eye movement artifacts only, and have not been shown to reliably identify artifacts caused by nonbiological origins like high-impedance electrodes. In this paper, we propose an automatic algorithm for the identification of general artifacts. The proposed algorithm consists of two parts: 1) an event-related feature-based clustering algorithm used to identify artifacts which have physiological origins; and 2) the electrode-scalp impedance information employed for identifying nonbiological artifacts. The results on EEG data collected from ten subjects show that our algorithm can effectively detect, separate, and remove both physiological and nonbiological artifacts. Qualitative evaluation of the reconstructed EEG signals demonstrates that our proposed method can effectively enhance the signal quality, especially the quality of ERPs, even for those that barely display ERPs in the raw EEG. The performance results also show that our proposed method can effectively identify artifacts and subsequently enhance the classification accuracies compared to four commonly used automatic artifact removal methods.

  3. MARSAME Radiological Release Report for Archaeological Artifacts Excavated from Area L

    Energy Technology Data Exchange (ETDEWEB)

    Ruedig, Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Whicker, Jeffrey Jay [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gillis, Jessica Mcdonnel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-03

    In 1991 Los Alamos National Laboratory’s (LANL’s) cultural resources team excavated archaeological site LA 4618 located at Technical Area 54, within Material Disposal Area L (MDA L). MDA L received non-radioactive chemical waste from the early 1960s until 1985. Further development of the MDA required excavation of several cultural sites under National Historic Preservation Act requirements; artifacts from these sites have been subsequently stored at LANL. The LANL cultural resources group would now like to release these artifacts to the Museum of Indian Arts and Culture in Santa Fe for curation. The history of disposal at Area L suggests that the artifact pool is unlikely to be chemically contaminated and LANL staff washed each artifact at least once following excavation. Thus, it is unlikely that the artifacts present a chemical hazard. LANL’s Environmental Stewardship group (EPC-ES) has evaluated the radiological survey results for the Area L artifact pool and found that the items described in this report meet the criteria for unrestricted radiological release under Department of Energy (DOE) Order 458.1 Radiation Protection of the Public and the Environment and are candidates for release without restriction from LANL control. This conclusion is based on the known history of MDA L and on radiation survey data.

  4. Evaluating an artifact in design science research

    CSIR Research Space (South Africa)

    Herselman, M

    2015-09-01

    Full Text Available In this paper, we describe the iterative evaluation of an artifact developed through the application of Design Science Research (DSR) methodology in a resource constrained environment. In the DSR process the aspect of evaluation is often done...

  5. How do bioethics teachers in Japan cope with ethical disagreement among healthcare university students in the classroom? A survey on educators in charge

    Science.gov (United States)

    Itai, K; Asai, A; Tsuchiya, Y; Onishi, M; Kosugi, S

    2006-01-01

    Objective The purpose of this study was to demonstrate how educators involved in the teaching of bioethics to healthcare university students in Japan would cope with ethical disagreement in the classroom, and to identify factors influencing them. Methods A cross sectional survey was conducted using self administered questionnaires mailed to a sample of university faculty in charge of bioethics curriculum for university healthcare students. Results A total of 107 usable questionnaires were returned: a response rate of 61.5%. When facing ethical disagreement in the classroom, coping behaviour differed depending on the topic of discussion, was influenced by educators' individual clear ethical attitudes regarding the topic of discussion, and was independent of many respondents' individual and social backgrounds. Among educators, it was commonly recognised that the purpose of bioethics education was to raise the level of awareness of ethical problems, to provide information about and knowledge of those issues, to raise students' sensitivity to ethical problems, and to teach students methods of reasoning and logical argument. Yet, despite this, several respondents considered the purpose of bioethics education to be to influence students about normative ethical judgments. There was no clear relationship, however, between ways of coping with ethical disagreement and educators' sense of the purpose of bioethics education. Conclusions This descriptive study suggests that educators involved in bioethics education for healthcare university students in Japan coped in various ways with ethical disagreement. Further research concerning ethical disagreement in educational settings is needed to provide better bioethics education for healthcare students. PMID:16648283

  6. Mediating Artifact in Teacher Professional Development

    Science.gov (United States)

    Svendsen, Bodil

    2015-07-01

    This article focuses on teacher professional development (TPD) in natural science through the 5E model as mediating artifact. The study was conducted in an upper secondary school, grounded in a school-based intervention research project. My contribution to the field of research on TPD is founded on the hypothesis that teachers would be best facilitated to make their practice more inquiry based if they are provided with a mediating artifact. In this study the artifact is a model 5E, which is a conceptual way of thinking, to help teachers reflect on their practice. The aim is to encourage teachers to make changes themselves, by applying extended use of inquiry into their practice. This mediated artifact could thus be used across different national contexts. The main research question is; how can the 5E model as a mediating artifact enhance TPD? The article addresses the processes of the use of the 5E model and its influence on teachers' perception of the model. This is in order for teachers to conceptualize their goals related to inquiry and scientific thinking, and to solve the problems involved in achieving those goals in their own contexts. The study concludes that, after the intervention, the teachers' approaches and strategies demonstrate greater emphasis on learning.

  7. Classroom Texting in College Students

    Science.gov (United States)

    Pettijohn, Terry F.; Frazier, Erik; Rieser, Elizabeth; Vaughn, Nicholas; Hupp-Wilds, Bobbi

    2015-01-01

    A 21-item survey on texting in the classroom was given to 235 college students. Overall, 99.6% of students owned a cellphone and 98% texted daily. Of the 138 students who texted in the classroom, most texted friends or significant others, and indicate the reason for classroom texting is boredom or work. Students who texted sent a mean of 12.21…

  8. The influence of a Classroom Model of Scientific Scholarship on Four Girls' Trajectories of Identification with Science

    Science.gov (United States)

    Cook, Melissa Sunshine

    This study examines the teacher's role in shaping the identity construction resources available in a classroom and the ways in which individual students take up, modify, and appropriate those resources to construct themselves as scientists through interaction with their teacher and peers. Drawing on frameworks of identity construction and social positioning, I propose that the locally-negotiated classroom-level cultural model of what it means to be a "good" science student forms the arena in which students construct a sense of their own competence at, affiliation with, and interest in science. The setting for this study was a 6th grade science class at a progressive urban elementary school whose population roughly represents the ethnic and socioeconomic diversity of the state of California. The teacher was an experienced science and math teacher interested in social justice and inquiry teaching. Drawing from naturalistic observations, video and artifact analysis, survey data, and repeated interviews with students and the teacher, I demonstrated what it meant to be a "good" science student in this particular cultural community by analyzing what was required, reinforced, and rewarded in this classroom. Next, I traced the influence of this particular classroom's conception of what it meant to be good at science on the trajectories of identification with science of four 6th grade girls selected to represent a variety of stances towards science, levels of classroom participation, and personal backgrounds. Scientific scholarship in this class had two parts: values related to science as a discipline, and a more generic set of school-related values one might see in any classroom. Different meanings of and values for science were indexed in the everyday activities of the classroom: science as a language for describing the natural world, science as a set of rhetorical values, science as an adult social community, and science as a place for mess and explosions. Among school

  9. Preserving ancient artifacts for the next millennia

    Science.gov (United States)

    Samuel L. Zelinka

    2014-01-01

    When wood is kept dry, it can remain intact for millennia, as evidenced by numerous artifacts from ancient Egypt (1). However, when wood interacts with water, numerous problems arise that can cause the wood to become permanently damaged or destroyed completely. Wood exhibits swelling on moisture uptake and shrinkage on drying, and these cyclical moisture changes lead...

  10. Cooperative learning, problem solving and mediating artifacts

    African Journals Online (AJOL)

    PROF.MIREKU

    The present study deals with the influence of cooperative learning on the ability of students to solve the problems. The study also concerns the introduction of mathematical mediating artifacts as factors which effect the learning of mathematics by students. Experimental research method of pre-test and post-test types was.

  11. Cooperative learning, problem solving and mediating artifacts ...

    African Journals Online (AJOL)

    The present study deals with the influence of cooperative learning on the ability of students to solve the problems. The study also concerns the introduction of mathematical mediating artifacts as factors which effect the learning of mathematics by students. Experimental research method of pre-test and post-test types was ...

  12. Cooperative learning, problem solving and mediating artifacts

    African Journals Online (AJOL)

    PROF.MIREKU

    African Journal of Educational Studies in Mathematics and Sciences Vol. 10, 2012. 39. Cooperative learning, problem solving and mediating artifacts. F. Bahmaei6 & N. Nejad Sadeghi. Abstract. The present study deals with the influence of cooperative learning on the ability of students to solve the problems. The study also ...

  13. The Many Faces of Computational Artifacts

    DEFF Research Database (Denmark)

    Christensen, Lars Rune; Harper, Richard

    2016-01-01

    the computational artifacts are both coordinative, image-generating, and intended for the control of nuclear-physical and chemical processes. Furthermore, the paper entails a critique of the notion of ‘computer support’, for not capturing the diverse constitutive powers of computer technology; its types if you will...

  14. Information Design for Visualizing History Museum Artifacts

    Science.gov (United States)

    Chen, Yulin; Lai, Tingsheng; Yasuda, Takami; Yokoi, Shigeki

    2011-01-01

    In the past few years, museum visualization systems have become a hot topic that attracts many researchers' interests. Several systems provide Web services for browsing museum collections through the Web. In this paper, we proposed an intelligent museum system for history museum artifacts, and described a study in which we enable access to China…

  15. A Social Language of Objects and Artifacts

    DEFF Research Database (Denmark)

    Svabo, Connie

    2007-01-01

    This paper is an inquiry about design. It gives an introductory overview of the vocabulary of 'materiality', which is used by a chosen selection of social theories. The paper shows a language of artifacts and objjects as it is used within practice-based approaches to knowing in organization  ...

  16. Model of Image Artifacts from Dust Particles

    Science.gov (United States)

    Willson, Reg

    2008-01-01

    A mathematical model of image artifacts produced by dust particles on lenses has been derived. Machine-vision systems often have to work with camera lenses that become dusty during use. Dust particles on the front surface of a lens produce image artifacts that can potentially affect the performance of a machine-vision algorithm. The present model satisfies a need for a means of synthesizing dust image artifacts for testing machine-vision algorithms for robustness (or the lack thereof) in the presence of dust on lenses. A dust particle can absorb light or scatter light out of some pixels, thereby giving rise to a dark dust artifact. It can also scatter light into other pixels, thereby giving rise to a bright dust artifact. For the sake of simplicity, this model deals only with dark dust artifacts. The model effectively represents dark dust artifacts as an attenuation image consisting of an array of diffuse darkened spots centered at image locations corresponding to the locations of dust particles. The dust artifacts are computationally incorporated into a given test image by simply multiplying the brightness value of each pixel by a transmission factor that incorporates the factor of attenuation, by dust particles, of the light incident on that pixel. With respect to computation of the attenuation and transmission factors, the model is based on a first-order geometric (ray)-optics treatment of the shadows cast by dust particles on the image detector. In this model, the light collected by a pixel is deemed to be confined to a pair of cones defined by the location of the pixel s image in object space, the entrance pupil of the lens, and the location of the pixel in the image plane (see Figure 1). For simplicity, it is assumed that the size of a dust particle is somewhat less than the diameter, at the front surface of the lens, of any collection cone containing all or part of that dust particle. Under this assumption, the shape of any individual dust particle artifact

  17. The Use and Abuse of Cell Phones and Text Messaging in the Classroom: A Survey of College Students

    Science.gov (United States)

    Tindell, Deborah R.; Bohlander, Robert W.

    2012-01-01

    As the use of mobile devices, such as cell phones, has proliferated in academic settings in recent years, new challenges are faced by institutions of higher education and their faculties. The authors surveyed 269 college students from 21 academic majors at a small northeastern university to gain a better understanding of the frequency and manner…

  18. Validation and Application of the Constructivist Learning Environment Survey in English Language Teacher Education Classrooms in Iran

    Science.gov (United States)

    Ebrahimi, Nabi. A.

    2015-01-01

    This article reports the validation and application of an English language teacher education (LTE) version of the Constructivist Learning Environment Survey (CLES). The instrument, called the CLES-LTE, was field tested with a sample of 622 Iranian English language student teachers in 28 classes. When principal components analysis led to the…

  19. Mammographic Artifacts on Full-Field Digital Mammography

    National Research Council Canada - National Science Library

    Choi, Jae Jeong; Kim, Sung Hun; Kang, Bong Joo; Choi, Byung Gil; Song, ByungJoo; Jung, Haijo

    2014-01-01

    This study investigates the incidence of full-field digital mammographic (FFDM) artifacts with three systems at two institutions and compares the artifacts between two detector types and two grid types...

  20. Contribution to faster artifact classification by creating an expert database

    OpenAIRE

    Maričić, Sven; Perinić, Mladen; Kovačević Pavičić, Daniela

    2011-01-01

    This paper proposes a method for faster classification of artifacts that appear during radiological recordings. Section images containing artifacts require significant additional post-processing time compared to other, artifact-free sections. The areas containing artifacts were identified and gradually analyzed in order to optimize the fabrication process. Guidelines for creation of an expert database are given. A suggestion is presented for defining a new expert knowledge database filling...

  1. A Language of Objects and Artifacts

    DEFF Research Database (Denmark)

    Svabo, Connie

    This is a conceptual inquiry about materiality. It gives an introductory overview to the vocabulary of materiality in a chosen selection of theories. The paper shows a language of artifacts and objects as it is used within practice-based approaches to organizational knowing. The examined intellec......, Gherardi &Yanow. In its cross-reading the paper explicitly focuses on the material sides of practice, where the primary concepts found are those of artifact and object....... concepts do the theories attempt to grasp tools and design objects – furniture, graphics, flutes-in-making and built space? The paper shows which concepts are used and it demonstrates how the interaction between social and material realities are viewed. Furthermore it highlights some of the ontological...

  2. The telomere lengthening conundrum - artifact or biology?

    DEFF Research Database (Denmark)

    Steenstrup, Troels; Hjelmborg, Jacob V B; Kark, Jeremy D

    2013-01-01

    Recent longitudinal studies of age-dependent leukocyte telomere length (LTL) attrition have reported that variable proportions of individuals experience LTL lengthening. Often, LTL lengthening has been taken at face value, and authors have speculated about the biological causation of this finding......-dependent LTL attrition in longitudinal studies. We find that LTL lengthening is far less frequent in studies with long follow-up periods and those that used a high-precision Southern blot method (as compared with quantitative polymerase chain reaction determination, which is associated with larger laboratory...... error). We conclude that the LTL lengthening observed in longitudinal studies is predominantly, if not entirely, an artifact of measurement error, which is exacerbated by short follow-up periods. We offer specific suggestions for design of longitudinal studies of LTL attrition to diminish this artifact....

  3. Supporting Knowledge Transfer through Decomposable Reasoning Artifacts

    Energy Technology Data Exchange (ETDEWEB)

    Pike, William A.; May, Richard A.; Turner, Alan E.

    2007-01-03

    Technology to support knowledge transfer and cooperative inquiry must offer its users the ability to effectively interpret knowledge structures produced by collaborators. Communicating the reasoning processes that underlie a finding is one method for enhancing interpretation, and can result in more effective evaluation and application of shared knowledge. In knowledge management tools, interpretation is aided by creating knowledge artifacts that can expose their provenance to scrutiny and that can be transformed into diverse representations that suit their consumers’ perspectives and preferences. We outline the information management needs of inquiring communities characterized by hypothesis generation tasks, and propose a model for communication, based in theories of hermeneutics, semiotics, and abduction, in which knowledge structures can be decomposed into the lower-level reasoning artifacts that produced them. We then present a proof-of-concept implementation for an environment to support the capture and communication of analytic products, with emphasis on the domain of intelligence analysis.

  4. All Together Now: Measuring Staff Cohesion in Special Education Classrooms

    Science.gov (United States)

    Kratz, Hilary E.; Locke, Jill; Piotrowski, Zinnia; Ouellette, Rachel R.; Xie, Ming; Stahmer, Aubyn C.; Mandell, David S.

    2015-01-01

    This study sought to validate a new measure, the Classroom Cohesion Survey (CCS), designed to examine the relationship between teachers and classroom assistants in autism support classrooms. Teachers, classroom assistants, and external observers showed good inter-rater agreement on the CCS and good internal consistency for all scales. Simple…

  5. Artifacts Of Spectral Analysis Of Instrument Readings

    Science.gov (United States)

    Wise, James H.

    1995-01-01

    Report presents experimental and theoretical study of some of artifacts introduced by processing outputs of two nominally identical low-frequency-reading instruments; high-sensitivity servo-accelerometers mounted together and operating, in conjunction with signal-conditioning circuits, as seismometers. Processing involved analog-to-digital conversion with anti-aliasing filtering, followed by digital processing including frequency weighting and computation of different measures of power spectral density (PSD).

  6. Delayed defibrillation caused by unexpected ECG artifact.

    Science.gov (United States)

    Stewart, John A

    2008-11-01

    Incorrect lead selection and unexpected ECG artifact during an attempted resuscitation after inhospital cardiac arrest resulted in undetected lack of cardiac monitoring for approximately 13 minutes. The patient was finally countershocked and regained a spontaneous pulse but was determined to have experienced profound neurologic damage and died shortly after being extubated. This type of failure may be common, particularly with older monitor/defibrillators. Caregivers, health care organizations, and device manufacturers should be aware of this potential problem and institute preventive measures.

  7. Panning artifacts in digital pathology images

    Science.gov (United States)

    Avanaki, Ali R. N.; Lanciault, Christian; Espig, Kathryn S.; Xthona, Albert; Kimpe, Tom R. L.

    2017-03-01

    In making a pathologic diagnosis, a pathologist uses cognitive processes: perception, attention, memory, and search (Pena and Andrade-Filho, 2009). Typically, this involves focus while panning from one region of a slide to another, using either a microscope in a traditional workflow or software program and display in a digital pathology workflow (DICOM Standard Committee, 2010). We theorize that during panning operation, the pathologist receives information important to diagnosis efficiency and/or correctness. As compared to an optical microscope, panning in a digital pathology image involves some visual artifacts due to the following: (i) the frame rate is finite; (ii) time varying visual signals are reconstructed using imperfect zero-order hold. Specifically, after pixel's digital drive is changed, it takes time for a pixel to emit the expected amount of light. Previous work suggests that 49% of navigation is conducted in low-power/overview with digital pathology (Molin et al., 2015), but the influence of display factors has not been measured. We conducted a reader study to establish a relationship between display frame rate, panel response time, and threshold panning speed (above which the artifacts become noticeable). Our results suggest visual tasks that involve tissue structure are more impacted by the simulated panning artifacts than those that only involve color (e.g., staining intensity estimation), and that the panning artifacts versus normalized panning speed has a peak behavior which is surprising and may change for a diagnostic task. This is work in progress and our final findings should be considered in designing future digital pathology systems.

  8. Engaging Instruction in Middle School Classrooms: An Observational Study of Nine Teachers

    Science.gov (United States)

    Raphael, Lisa M.; Pressley, Michael; Mohan, Lindsey

    2008-01-01

    Observations of instructional practices, teacher interviews, and classroom artifacts were collected in 9 sixth-grade classrooms in 2 middle schools to determine teaching practices associated with student engagement (i.e., being on task, doing thoughtful assignments). The teachers used a variety of instructional practices, with some teachers…

  9. Ultrasound artifacts mimicking pleural sliding after pneumonectomy.

    Science.gov (United States)

    Cavaliere, Franco; Zamparelli, Roberto; Soave, Maurizio P; Gargaruti, Riccardo; Scapigliati, Andrea; De Paulis, Stefano

    2014-03-01

    To determine the presence of pleural sliding on chest ultrasonography (US) in a series of patients admitted to a surgical intensive care unit (SICU). Prospective, observational study. 16-bed SICU of a University hospital. 8 patients (7 men, 1 woman), aged 64 - 73 years (mean 67.5 yrs). Seven patients underwent pneumonectomy for pulmonary neoplasms; one patient underwent an atypical lung resection after having undergone a pneumonectomy one year before. None. Chest ultrasounds were performed during mechanical ventilation and spontaneous ventilation after endotracheal tube removal. In both examinations, pleural sliding was searched bilaterally in brightness mode (B-mode) and motion mode (M-mode) on the anterior thoracic wall in the least gravitationally dependent areas. During mechanical ventilation, pleural sliding was always absent on the side of the pneumonectomy and present on the other side. During spontaneous ventilation, some artifacts mimicking pleural sliding were noted on the side of the pneumonectomy both in B-mode and M-mode (presence of the seashore sign) in all patients, except for the one patient who had undergone a pneumonectomy one year earlier. Those artifacts became more pronounced during deep breaths. Ultrasound artifacts mimicking pleural sliding may be observed in the absence of the lung and may originate from the activity of intercostal muscles since they become more evident during deep breathing. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Sampling Artifacts from Conductive Silicone Tubing

    Energy Technology Data Exchange (ETDEWEB)

    Timko, Michael T.; Yu, Zhenhong; Kroll, Jesse; Jayne, John T.; Worsnop, Douglas R.; Miake-Lye, Richard C.; Onasch, Timothy B.; Liscinsky, David; Kirchstetter, Thomas W.; Destaillats, Hugo; Holder, Amara L.; Smith, Jared D.; Wilson, Kevin R.

    2009-05-15

    We report evidence that carbon impregnated conductive silicone tubing used in aerosol sampling systems can introduce two types of experimental artifacts: 1) silicon tubing dynamically absorbs carbon dioxide gas, requiring greater than 5 minutes to reach equilibrium and 2) silicone tubing emits organic contaminants containing siloxane that adsorb onto particles traveling through it and onto downstream quartz fiber filters. The consequence can be substantial for engine exhaust measurements as both artifacts directly impact calculations of particulate mass-based emission indices. The emission of contaminants from the silicone tubing can result in overestimation of organic particle mass concentrations based on real-time aerosol mass spectrometry and the off-line thermal analysis of quartz filters. The adsorption of siloxane contaminants can affect the surface properties of aerosol particles; we observed a marked reduction in the water-affinity of soot particles passed through conductive silicone tubing. These combined observations suggest that the silicone tubing artifacts may have wide consequence for the aerosol community and should, therefore, be used with caution. Gentle heating, physical and chemical properties of the particle carriers, exposure to solvents, and tubing age may influence siloxane uptake. The amount of contamination is expected to increase as the tubing surface area increases and as the particle surface area increases. The effect is observed at ambient temperature and enhanced by mild heating (<100 oC). Further evaluation is warranted.

  11. Color Doppler artifact in anechoic regions.

    Science.gov (United States)

    Mitchell, D G; Burns, P; Needleman, L

    1990-05-01

    For color Doppler imaging, several types of signal processing are employed in order to produce acceptable images of blood flow in blood vessels while suppressing color in moving solid tissue. The processing can produce an artifact in which color may arise from noise or from tissue motion and fill anechoic regions preferentially. This artifact may complicate the differentiation of areas with blood flow from anechoic regions without flow. By using four different color Doppler ultrasound units to image a tissue-equivalent phantom containing anechoic cylinders, artifactual color resulted when gain was raised sufficiently. This color was concentrated in anechoic regions of a gray-scale image that did not contain flow. In two instruments, this artifact was only observed when the transducer was vibrated, simulating tissue motion. In these instruments, the identification of low-frequency, high-amplitude Doppler signals is used to locate moving solid tissue and so suppress color in these regions. In the other two instruments, the presence of echoes within the image suppressed the assignment of color. With both types of processing, color may appear artifactually in echo-free regions without flow, such as fluid collections. Presence or absence of flow should be confirmed by Doppler spectral analysis. An understanding of the origin and appearance of artifactual color can prevent its occurrence from detracting from the usefulness of color Doppler imaging.

  12. Ultrasound artifacts: classification, applied physics with illustrations, and imaging appearances.

    Science.gov (United States)

    Prabhu, Somnath J; Kanal, Kalpana; Bhargava, Puneet; Vaidya, Sandeep; Dighe, Manjiri K

    2014-06-01

    Ultrasound has become a widely used diagnostic imaging modality in medicine because of its safety and portability. Because of rapid advances in technology, in recent years, sonographic imaging quality has significantly increased. Despite these advances, the potential to encounter artifacts while imaging remains.This article classifies both common and uncommon gray-scale and Doppler ultrasound artifacts into those resulting from physiology and those caused by hardware. A brief applied-physics explanation for each artifact is listed along with an illustrated diagram. The imaging appearance of artifacts is presented in case examples, along with strategies to minimize the artifacts in real time or use them for clinical advantage where applicable.

  13. Voting strategy for artifact reduction in digital breast tomosynthesis.

    Science.gov (United States)

    Wu, Tao; Moore, Richard H; Kopans, Daniel B

    2006-07-01

    Artifacts are observed in digital breast tomosynthesis (DBT) reconstructions due to the small number of projections and the narrow angular range that are typically employed in tomosynthesis imaging. In this work, we investigate the reconstruction artifacts that are caused by high-attenuation features in breast and develop several artifact reduction methods based on a "voting strategy." The voting strategy identifies the projection(s) that would introduce artifacts to a voxel and rejects the projection(s) when reconstructing the voxel. Four approaches to the voting strategy were compared, including projection segmentation, maximum contribution deduction, one-step classification, and iterative classification. The projection segmentation method, based on segmentation of high-attenuation features from the projections, effectively reduces artifacts caused by metal and large calcifications that can be reliably detected and segmented from projections. The other three methods are based on the observation that contributions from artifact-inducing projections have higher value than those from normal projections. These methods attempt to identify the projection(s) that would cause artifacts by comparing contributions from different projections. Among the three methods, the iterative classification method provides the best artifact reduction; however, it can generate many false positive classifications that degrade the image quality. The maximum contribution deduction method and one-step classification method both reduce artifacts well from small calcifications, although the performance of artifact reduction is slightly better with the one-step classification. The combination of one-step classification and projection segmentation removes artifacts from both large and small calcifications.

  14. Classroom Management

    OpenAIRE

    Jasmina Delceva – Dizdarevik

    2008-01-01

    This paper is aiming to discover the paths that enable teachers to manage their work with students in the classroom. To be an efficient teacher means to know with what and how to motivate students to learn. Teacher as an efficient classroom manager needs to have skills to plan and prepare the education process, know how to organize the teaching and how to guide the class. An efficient teacher moreover needs o establish positive classroom climate and working discipline. Also, teacher should be...

  15. Medication-related cognitive artifacts used by older adults with heart failure.

    Science.gov (United States)

    Mickelson, Robin S; Willis, Matt; Holden, Richard J

    2015-12-01

    To use a human factors perspective to examine how older adult patients with heart failure use cognitive artifacts for medication management. We performed a secondary analysis of data collected from 30 patients and 14 informal caregivers enrolled in a larger study of heart failure self-care. Data included photographs, observation notes, interviews, video recordings, medical record data, and surveys. These data were analyzed using an iterative content analysis. Findings revealed that medication management was complex, inseparable from other patient activities, distributed across people, time, and place, and complicated by knowledge gaps. We identified fifteen types of cognitive artifacts including medical devices, pillboxes, medication lists, and electronic personal health records used for: 1) measurement/evaluation; 2) tracking/communication; 3) organization/administration; and 4) information/sensemaking. These artifacts were characterized by fit and misfit with the patient's sociotechnical system and demonstrated both advantages and disadvantages. We found that patients often modified or "finished the design" of existing artifacts and relied on "assemblages" of artifacts, routines, and actors to accomplish their self-care goals. Cognitive artifacts are useful but sometimes are poorly designed or are not used optimally. If appropriately designed for usability and acceptance, paper-based and computer-based information technologies can improve medication management for individuals living with chronic illness. These technologies can be designed for use by patients, caregivers, and clinicians; should support collaboration and communication between these individuals; can be coupled with home-based and wearable sensor technology; and must fit their users' needs, limitations, abilities, tasks, routines, and contexts of use.

  16. Gestures as Semiotic Resources in the Mathematics Classroom

    Science.gov (United States)

    Arzarello, Ferdinando; Paola, Domingo; Robutti, Ornella; Sabena, Cristina

    2009-01-01

    In this paper, we consider gestures as part of the resources activated in the mathematics classroom: speech, inscriptions, artifacts, etc. As such, gestures are seen as one of the semiotic tools used by students and teacher in mathematics teaching-learning. To analyze them, we introduce a suitable model, the "semiotic bundle." It allows focusing…

  17. Coordinate Measuring Machine Pit Artifact Inspection Procedure

    Energy Technology Data Exchange (ETDEWEB)

    Montano, Joshua D. [Los Alamos National Laboratory

    2012-07-31

    The goal of this document is to outline a procedure for dimensional measurement of Los Alamos National Laboratory's CMM Pit Artifact. This procedure will be used by the Manufacturing Practice's Inspection Technology Subgroup of the Interagency Manufacturing Operations Group and Joint Operations Weapon Operations Group (IMOG/JOWOG 39) round robin participants. The intent is to assess the state of industry within the Nuclear Weapons Complex for measurements made on this type of part and find which current measurement strategies and techniques produce the best results.

  18. Accessing Cultural Artifacts Through Digital Companions

    DEFF Research Database (Denmark)

    Rehm, Matthias; Jensen, Martin Lynge

    2015-01-01

    This paper presents a study that explores how the introduction of a digital companion agent for a museum exploration game changes children’s engagement with the presented artworks. To this end, a mobile application was developed featuring a monster agent that has eaten the artworks, which the chi...... the children had now to find in the museum. Results show that in comparison to the paper-based version of the exploration game, children engaged in more interactions with the actual cultural artifacts and showed a significantly higher retention rate for details of the involved artworks....

  19. Hair product artifact in magnetic resonance imaging.

    Science.gov (United States)

    Chenji, Sneha; Wilman, Alan H; Mah, Dennell; Seres, Peter; Genge, Angela; Kalra, Sanjay

    2017-01-01

    The presence of metallic compounds in facial cosmetics and permanent tattoos may affect the quality of magnetic resonance imaging. We report a case study describing a signal artifact due to the use of a leave-on powdered hair dye. On reviewing the ingredients of the product, it was found to contain several metallic compounds. In lieu of this observation, we suggest that MRI centers include the use of metal- or mineral-based facial cosmetics or hair products in their screening protocols. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Ontological System for Context Artifacts and Resources

    Science.gov (United States)

    Huang, T.; Chung, N. T.; Mukherjee, R. M.

    2012-12-01

    The Adaptive Vehicle Make (AVM) program is a portfolio of programs, managed by the Defense Advanced Research Projects Agency (DARPA). It was established to revolutionize how DoD designs, verifies, and manufactures complex defense systems and vehicles. The Component, Context, and Manufacturing Model Library (C2M2L; pronounced "camel") seeks to develop domain-specific models needed to enable design, verification, and fabrication of the Fast Adaptable Next-Generation (FANG) infantry fighting vehicle using in its overall infrastructure. Terrain models are being developed to represent the surface/fluid that an amphibious infantry fighting vehicle would traverse, ranging from paved road surfaces to rocky, mountainous terrain, slope, discrete obstacles, mud, sand snow, and water fording. Context models are being developed to provide additional data for environmental factors, such as: humidity, wind speed, particulate presence and character, solar radiation, cloud cover, precipitation, and more. The Ontological System for Context Artifacts and Resources (OSCAR) designed and developed at the Jet Propulsion Laboratory is semantic web data system that enables context artifacts to be registered and searched according to their meaning, rather than indexed according to their syntactic structure alone (as in the case for traditional search engines). The system leverages heavily on the Semantic Web for Earth and Environmental Terminology (SWEET) ontologies to model physical terrain environment and context model characteristics. In this talk, we focus on the application of the SWEET ontologies and the design of the OSCAR system architecture.

  1. Flipped classroom

    DEFF Research Database (Denmark)

    Skov, Tobias Kidde; Jørgensen, Søren

    2016-01-01

    Artiklen beskriver Flipped Classroom som et didaktisk princip, der kan være med til at organisere og tilrettelægge en undervisning, med fokus på forskellige læringsformer. Det handler om at forstå Flipped Classroom som en opdeling i 2 faser og 3 led, som samlet set skaber en didaktisk organisering....

  2. Classrooms as

    African Journals Online (AJOL)

    also supplied a means for students to develop relationships with their peers as ... promoting 'real world' skills they could transfer outside of the classroom and into their lives. ... Keywords: digital storytelling, classrooms as safe houses, personal writing, ...... British Journal of Educational Technology, DOI: 10.1111/bjet.12540.

  3. Elimination of periodic damped artifacts in scanning probe microscopy images

    Science.gov (United States)

    Chen, Yuhang; Huang, Wenhao

    2010-04-01

    When scanning probe microscopy (SPM) is operated at high scan rates, stripe-like artifacts will appear frequently in the SPM images. The removal of the image artifacts is highly demanded because they will distort the results in precise measurements. In this work, a method based on Prony analysis has been introduced to erase such periodic damped artifacts. Results demonstrate that this method prevails against the conventional fast Fourier transformation (FFT) method. Clean eliminations of the image artifacts are obtained, with almost no sacrifice of the detailed surface information. Even for arbitrary rough surfaces, the image artifacts can also be reduced by more than one order of magnitude. However, small amounts of stripes may still remain in the images. In these cases, the Prony analysis combined with locally weighted smoothing will provide better image quality. The artifacts reduction can have a meaning in the SPM-based visualization of dynamic phenomena with a nanoscale resolution.

  4. A Review on Machine Learning Algorithms in Handling EEG Artifacts

    OpenAIRE

    Barua, Shaibal; Begum, Shahina

    2014-01-01

    Brain waves obtained by Electroencephalograms (EEG) recording are an important research area in medical and health and brain computer interface (BCI). Due to the nature of EEG signal, noises and artifacts can contaminate it, which leads to a serious misinterpretation in EEG signal analysis. These contaminations are referred to as artifacts, which are signals of other than brain activity. Moreover, artifacts can cause significant miscalculation of the EEG measurements that reduces the clinical...

  5. Enterprise Architecture Artifacts as Boundary Objects - A Framework of Properties

    OpenAIRE

    Abraham, Ralf

    2013-01-01

    This paper uses the concept of boundary objects to derive hypotheses for the design of Enterprise Architecture (EA) artifacts. Boundary objects are a useful concept to understand the coordinative role of artifacts in practice, making them a proper vehicle to analyze how EA artifacts can be designed to support communication and coordination during enterprise transformation. Since enterprise transformation projects typically involve multiple communities of practice, communication and coordinati...

  6. Discriminative Ocular Artifact Correction for Feature Learning in EEG Analysis.

    Science.gov (United States)

    Xinyang Li; Cuntai Guan; Haihong Zhang; Kai Keng Ang

    2017-08-01

    Electrooculogram (EOG) artifact contamination is a common critical issue in general electroencephalogram (EEG) studies as well as in brain-computer interface (BCI) research. It is especially challenging when dedicated EOG channels are unavailable or when there are very few EEG channels available for independent component analysis based ocular artifact removal. It is even more challenging to avoid loss of the signal of interest during the artifact correction process, where the signal of interest can be multiple magnitudes weaker than the artifact. To address these issues, we propose a novel discriminative ocular artifact correction approach for feature learning in EEG analysis. Without extra ocular movement measurements, the artifact is extracted from raw EEG data, which is totally automatic and requires no visual inspection of artifacts. Then, artifact correction is optimized jointly with feature extraction by maximizing oscillatory correlations between trials from the same class and minimizing them between trials from different classes. We evaluate this approach on a real-world EEG dataset comprising 68 subjects performing cognitive tasks. The results showed that the approach is capable of not only suppressing the artifact components but also improving the discriminative power of a classifier with statistical significance. We also demonstrate that the proposed method addresses the confounding issues induced by ocular movements in cognitive EEG study.

  7. Artifact removal from EEG data with empirical mode decomposition

    Science.gov (United States)

    Grubov, Vadim V.; Runnova, Anastasiya E.; Efremova, Tatyana Yu.; Hramov, Alexander E.

    2017-03-01

    In the paper we propose the novel method for dealing with the physiological artifacts caused by intensive activity of facial and neck muscles and other movements in experimental human EEG recordings. The method is based on analysis of EEG signals with empirical mode decomposition (Hilbert-Huang transform). We introduce the mathematical algorithm of the method with following steps: empirical mode decomposition of EEG signal, choosing of empirical modes with artifacts, removing empirical modes with artifacts, reconstruction of the initial EEG signal. We test the method on filtration of experimental human EEG signals from movement artifacts and show high efficiency of the method.

  8. Artifacts in contrast-enhanced ultrasound: a pictorial essay.

    Science.gov (United States)

    Fetzer, David T; Rafailidis, Vasileios; Peterson, Cynthia; Grant, Edward G; Sidhu, Paul; Barr, Richard G

    2017-12-02

    Although contrast-enhanced ultrasound (CEUS) has become a widely utilized and accepted modality in much of the world, the associated contrast agents have only recently received approval in the United States. As with all radiological techniques, image artifacts are encountered in CEUS, some of which relate to commonly encountered ultrasound artifacts, while others are unique to this technique. Image artifacts must be recognized when performing and interpreting examinations to improve technique and diagnostic accuracy. In this article, we review artifacts that may be encountered in CEUS, and where possible discuss how to minimize them or mitigate their effect on image quality and interpretation.

  9. SURVEY

    DEFF Research Database (Denmark)

    SURVEY er en udbredt metode og benyttes inden for bl.a. samfundsvidenskab, humaniora, psykologi og sundhedsforskning. Også uden for forskningsverdenen er der mange organisationer som f.eks. konsulentfirmaer og offentlige institutioner samt marketingsafdelinger i private virksomheder, der arbejder...

  10. Persuasion through artifacts: Sociological and psychological dimensions

    Directory of Open Access Journals (Sweden)

    Stroe Mihaela

    2015-01-01

    Full Text Available Research suggests that applicants use various impression management tactics during employment interviews to influence interviewers' evaluations of their performance. Yet, little research has examined inteviewers/perceptions of applicant's impression management and their degree of nonverbal influence. This PhD study examines these questions, using both quantitative and qualitative data: Do interviewers accurately perceive applicant's impression management tactics? How are these perceptions integrated into their evaluations of applicant's nonverbal behaviour? Is perception accuracy influenced by artifacts (professional clothing that interviewees wear? It has cross-cultural design, because describes the differences in European Commission interviewers' social perceptions and Romanian human resources managers on one hand, and between social perceptions of European Commission public servants and Romanian employees on the other hand, concerning 12 key concepts: persuasion, first impressions, professional image, credibility, authenticity, competence, self- confidence, self-management, self-presentation, self-promotion, impression management tactics, professional appearance.

  11. Medical image of the week: polysomnogram artifact

    Directory of Open Access Journals (Sweden)

    Bartell J

    2015-02-01

    Full Text Available A 54 year-old man with a past medical history of attention deficit hyperactivity disorder (ADHD, low back pain, and paroxysmal supraventricular tachycardia presented to the sleep laboratory for evaluation of sleep disordered breathing. Pertinent medications include fluoxetine, ambien, and clonazepam. His Epworth sleepiness score was 18. He had a total sleep time of 12 min. On the night of his sleep study, the patient was restless and repeatedly changed positions in bed. Figures 1 and 2 show the artifact determined to be lead displacement of O1M2 after the patient shifted in bed, inadvertently removing one of his scalp electrodes. The sine waves are 60 Hz in frequency. Once the problem was identified, the lead was quickly replaced to its proper position.

  12. Prior-based artifact correction (PBAC) in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Heußer, Thorsten, E-mail: thorsten.heusser@dkfz-heidelberg.de; Brehm, Marcus [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Ritschl, Ludwig [Ziehm Imaging GmbH, Donaustraße 31, 90451 Nürnberg (Germany); Sawall, Stefan; Kachelrieß, Marc [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Institute of Medical Physics, Friedrich–Alexander–University (FAU) of Erlangen–Nürnberg, Henkestraße 91, 91052 Erlangen (Germany)

    2014-02-15

    Purpose: Image quality in computed tomography (CT) often suffers from artifacts which may reduce the diagnostic value of the image. In many cases, these artifacts result from missing or corrupt regions in the projection data, e.g., in the case of metal, truncation, and limited angle artifacts. The authors propose a generalized correction method for different kinds of artifacts resulting from missing or corrupt data by making use of available prior knowledge to perform data completion. Methods: The proposed prior-based artifact correction (PBAC) method requires prior knowledge in form of a planning CT of the same patient or in form of a CT scan of a different patient showing the same body region. In both cases, the prior image is registered to the patient image using a deformable transformation. The registered prior is forward projected and data completion of the patient projections is performed using smooth sinogram inpainting. The obtained projection data are used to reconstruct the corrected image. Results: The authors investigate metal and truncation artifacts in patient data sets acquired with a clinical CT and limited angle artifacts in an anthropomorphic head phantom data set acquired with a gantry-based flat detector CT device. In all cases, the corrected images obtained by PBAC are nearly artifact-free. Compared to conventional correction methods, PBAC achieves better artifact suppression while preserving the patient-specific anatomy at the same time. Further, the authors show that prominent anatomical details in the prior image seem to have only minor impact on the correction result. Conclusions: The results show that PBAC has the potential to effectively correct for metal, truncation, and limited angle artifacts if adequate prior data are available. Since the proposed method makes use of a generalized algorithm, PBAC may also be applicable to other artifacts resulting from missing or corrupt data.

  13. Incidental ferumoxytol artifacts in clinical brain MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bowser, Bruce A.; Campeau, Norbert G.; Carr, Carrie M.; Diehn, Felix E.; McDonald, Jennifer S.; Miller, Gary M.; Kaufmann, Timothy J. [Mayo Clinic, Department of Radiology, Rochester, MN (United States)

    2016-11-15

    Ferumoxytol (Feraheme) is a parenteral therapy approved for treatment of iron deficiency anemia. The product insert for ferumoxytol states that it may affect the diagnostic ability of MRI for up to 3 months. However, the expected effects may not be commonly recognized among clinical neuroradiologists. Our purpose is to describe the artifacts we have seen at our institution during routine clinical practice. We reviewed the patients at our institution that had brain MRI performed within 90 days of receiving intravenous ferumoxytol. The imaging was reviewed for specific findings, including diffusion-weighted imaging vascular susceptibility artifact, gradient-echo echo-planar T2*-weighted vascular susceptibility artifact, SWI/SWAN vascular susceptibility artifact, hypointense vascular signal on T2-weighted images, pre-gadolinium contrast vascular enhancement on magnetization-prepared rapid acquisition gradient echo (MPRAGE) imaging, and effects on post-gadolinium contrast T1 imaging. Multiple artifacts were observed in patients having a brain MRI within 3 days of receiving intravenous ferumoxytol. These included susceptibility artifact on DWI, GRE, and SWAN/SWI imaging, pre-gadolinium contrast increased vascular signal on MPRAGE imaging, and decreased expected enhancement on post-gadolinium contrast T1-weighted imaging. Ferumoxytol can create imaging artifacts which complicate clinical interpretation when brain MRI is performed within 3 days of administration. Recognition of the constellation of artifacts produced by ferumoxytol is important in order to obviate additional unnecessary examinations and mitigate errors in interpretation. (orig.)

  14. Quantification of Rain Induced Artifacts on Digital Satellite Television ...

    African Journals Online (AJOL)

    The presence of artifacts on the high definition television (TV) content and the eventual loss of the digital TV signals to rain is still a major concern to satellite operators, ... The degrading effect is assessed using a subjective experimental approach, which is based on the quantification of the artifacts ruining user's Quality of ...

  15. Contrast artifacts in tapping tip atomic force microscopy

    DEFF Research Database (Denmark)

    Kyhle, Anders; Sørensen, Alexis Hammer; Zandbergen, Julie Bjerring

    1998-01-01

    When recording images with an atomic force microscope using the resonant vibrating cantilever mode, surprising strange results are often achieved. Typical artifacts are strange contours, unexpected height shifts, and sudden changes of the apparent resolution in the acquired images. Such artifacts...

  16. A new EEG artifact specific to digital acquisition.

    Science.gov (United States)

    Maus, Douglas

    2013-02-01

    To increase awareness in electroencephalographers of a new digital-specific artifact that could be falsely interpreted as epileptiform. Several examples of this artifact were discovered in clinical EEG recording. Examples of the clinical recording are presented using custom software to highlight the artifact. The underlying digital data were examined with standard hexadecimal editing software to verify the exact binary duplication error. The artifact appears as repetitions of very brief intervals (50 milliseconds). In channels in which the signal has a large excursion (sharp slope) over this time frame, the repetition of a 50-millisecond interval could appear similar to polyspikes. In one instance, such a misinterpretation led to a technologist instructing a patient to remain in the clinic because of an "abnormality." Artifacts that mislead the electroencephalographer are serious problems that can lead to erroneous affirmative diagnoses. The transition to digital acquisition brings the potential for new digital-specific errors. This report describes one such new digital artifact, discusses a conjecture for the stage of hardware where the artifact arises, suggests strategies for electroencephalographers to identify this artifact, and provides recommendations to clinical hardware vendors to avoid this error.

  17. CLASSROOM MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Jasmina Delceva – Dizdarevik

    2014-06-01

    Full Text Available This paper is aiming to discover the paths that enable teachers to manage their work with students in the classroom. To be an efficient teacher means to know with what and how to motivate students to learn. Teacher as an efficient classroom manager needs to have skills to plan and prepare the education process, know how to organize the teaching and how to guide the class. An efficient teacher moreover needs o establish positive classroom climate and working discipline. Also, teacher should be able to evaluate the progress of the students and self-evaluate his own work.In order to examine classroom management skills of teachers in Republic of Macedonia, a research has been made for teachers in primary schools in Republic of Macedonia. Instruments which will be used in order to complete the research and analyses are the following: questionnaire for teachers and educational policy analyses in our country in order to discover whether there is concrete strategy for promotion and implementation of classroom management on local and national level.Analyses of results show that there is a deficit of classroom management skills among teachers, which is due moreover to some lapses in initial education of teachers.

  18. Body MR Imaging: Artifacts, k-Space, and Solutions

    Science.gov (United States)

    Seethamraju, Ravi T.; Patel, Pritesh; Hahn, Peter F.; Kirsch, John E.; Guimaraes, Alexander R.

    2015-01-01

    Body magnetic resonance (MR) imaging is challenging because of the complex interaction of multiple factors, including motion arising from respiration and bowel peristalsis, susceptibility effects secondary to bowel gas, and the need to cover a large field of view. The combination of these factors makes body MR imaging more prone to artifacts, compared with imaging of other anatomic regions. Understanding the basic MR physics underlying artifacts is crucial to recognizing the trade-offs involved in mitigating artifacts and improving image quality. Artifacts can be classified into three main groups: (a) artifacts related to magnetic field imperfections, including the static magnetic field, the radiofrequency (RF) field, and gradient fields; (b) artifacts related to motion; and (c) artifacts arising from methods used to sample the MR signal. Static magnetic field homogeneity is essential for many MR techniques, such as fat saturation and balanced steady-state free precession. Susceptibility effects become more pronounced at higher field strengths and can be ameliorated by using spin-echo sequences when possible, increasing the receiver bandwidth, and aligning the phase-encoding gradient with the strongest susceptibility gradients, among other strategies. Nonuniformities in the RF transmit field, including dielectric effects, can be minimized by applying dielectric pads or imaging at lower field strength. Motion artifacts can be overcome through respiratory synchronization, alternative k-space sampling schemes, and parallel imaging. Aliasing and truncation artifacts derive from limitations in digital sampling of the MR signal and can be rectified by adjusting the sampling parameters. Understanding the causes of artifacts and their possible solutions will enable practitioners of body MR imaging to meet the challenges of novel pulse sequence design, parallel imaging, and increasing field strength. ©RSNA, 2015 PMID:26207581

  19. Boundary Negotiating Artifacts in Personal Informatics: Patient-Provider Collaboration with Patient-Generated Data.

    Science.gov (United States)

    Chung, Chia-Fang; Dew, Kristin; Cole, Allison; Zia, Jasmine; Fogarty, James; Kientz, Julie A; Munson, Sean A

    2016-02-27

    Patient-generated data is increasingly common in chronic disease care management. Smartphone applications and wearable sensors help patients more easily collect health information. However, current commercial tools often do not effectively support patients and providers in collaboration surrounding these data. This paper examines patient expectations and current collaboration practices around patient-generated data. We survey 211 patients, interview 18 patients, and re-analyze a dataset of 21 provider interviews. We find that collaboration occurs in every stage of self-tracking and that patients and providers create boundary negotiating artifacts to support the collaboration. Building upon current practices with patient-generated data, we use these theories of patient and provider collaboration to analyze misunderstandings and privacy concerns as well as identify opportunities to better support these collaborations. We reflect on the social nature of patient-provider collaboration to suggest future development of the stage-based model of personal informatics and the theory of boundary negotiating artifacts.

  20. [Joint correction for motion artifacts and off-resonance artifacts in multi-shot diffusion magnetic resonance imaging].

    Science.gov (United States)

    Wu, Wenchuan; Fang, Sheng; Guo, Hua

    2014-06-01

    Aiming at motion artifacts and off-resonance artifacts in multi-shot diffusion magnetic resonance imaging (MRI), we proposed a joint correction method in this paper to correct the two kinds of artifacts simultaneously without additional acquisition of navigation data and field map. We utilized the proposed method using multi-shot variable density spiral sequence to acquire MRI data and used auto-focusing technique for image deblurring. We also used direct method or iterative method to correct motion induced phase errors in the process of deblurring. In vivo MRI experiments demonstrated that the proposed method could effectively suppress motion artifacts and off-resonance artifacts and achieve images with fine structures. In addition, the scan time was not increased in applying the proposed method.

  1. Working with Corpora in the Translation Classroom

    Science.gov (United States)

    Krüger, Ralph

    2012-01-01

    This article sets out to illustrate possible applications of electronic corpora in the translation classroom. Starting with a survey of corpus use within corpus-based translation studies, the didactic value of corpora in the translation classroom and their epistemic value in translation teaching and practice will be elaborated. A typology of…

  2. Examining Interactivity in Synchronous Virtual Classrooms

    Science.gov (United States)

    Martin, Florence; Parker, Michele A.; Deale, Deborah F.

    2012-01-01

    Interaction is crucial to student satisfaction in online courses. Adding synchronous components (virtual classroom technologies) to online courses can facilitate interaction. In this study, interaction within a synchronous virtual classroom was investigated by surveying 21 graduate students in an instructional technology program in the…

  3. On the Use of Cell Phones and Other Electronic Devices in the Classroom: Evidence from a Survey of Faculty and Students

    Science.gov (United States)

    Baker, William M.; Lusk, Edward J.; Neuhauser, Karyn L.

    2012-01-01

    The authors investigated faculty and student perceptions regarding the use of cell phones and other electronic devices in the classroom. Students differed markedly from faculty, with students exhibiting much greater acceptance of in-class use of technology. Among students, the authors found that gender affected perceptions. Specifically, male…

  4. CT Dental Artifact: Comparison of an Iterative Metal Artifact Reduction Technique with Weighted Filtered Back-Projection

    Science.gov (United States)

    Michalak, Gregory J; DeLone, David R; Kotsenas, Amy L; Lindell, E Paul; McCollough, Cynthia H; Fletcher, Joel G

    2017-01-01

    Background Dental hardware produces streak artifacts on computed tomography (CT) images reconstructed with the standard weighted filtered back projection (wFBP) method. Purpose To perform a preliminary evaluation of an iterative metal artifact reduction (IMAR) technique to assess its ability to improve anatomic visualization over wFBP in patients with dental amalgam or other hardware. Material and Methods CT images from patients with dental hardware were reconstructed using wFBP and IMAR software and soft-tissue or bone window/level settings. The anatomy most affected by metal artifacts was identified. Two neuroradiologists determined subjective and objective imaging features, including overall metal artifact score (1 = severe artifacts, 5 = no artifacts), soft-tissue visualization score of the most-compromised structure, and artifact length along the skin surface. CT numbers were used to quantify artifact severity. Results Twenty-four patients were included. IMAR improved overall metal artifact score in 18/24 cases (median =2 ± 0.9 vs. 1 ± 0.6, P IMAR (94.6 vs. 219 HU, P = 0.002) and length of affected skin surface decreased (40.4 mm vs. 118.7 mm, P IMAR vs. 11/24 with wFBP. Conclusion IMAR software reduced metal artifact both subjectively and objectively and improved visualization of adjacent soft tissues. However, it produced a higher rate of artifactual defects in the teeth and bones than wFBP. Our findings support the use of IMAR as a valuable complement to, but not a replacement for, standard wFBP image reconstruction. PMID:29225924

  5. Searching for alien artifacts on the moon

    Science.gov (United States)

    Davies, P. C. W.; Wagner, R. V.

    2013-08-01

    The Search for Extraterrestrial Intelligence (SETI) has a low probability of success, but it would have a high impact if successful. Therefore it makes sense to widen the search as much as possible within the confines of the modest budget and limited resources currently available. To date, SETI has been dominated by the paradigm of seeking deliberately beamed radio messages. However, indirect evidence for extraterrestrial intelligence could come from any incontrovertible signatures of non-human technology. Existing searchable databases from astronomy, biology, earth and planetary sciences all offer low-cost opportunities to seek a footprint of extraterrestrial technology. In this paper we take as a case study one particular new and rapidly-expanding database: the photographic mapping of the Moon's surface by the Lunar Reconnaissance Orbiter (LRO) to 0.5 m resolution. Although there is only a tiny probability that alien technology would have left traces on the moon in the form of an artifact or surface modification of lunar features, this location has the virtue of being close, and of preserving traces for an immense duration. Systematic scrutiny of the LRO photographic images is being routinely conducted anyway for planetary science purposes, and this program could readily be expanded and outsourced at little extra cost to accommodate SETI goals, after the fashion of the SETI@home and Galaxy Zoo projects.

  6. Colorectal Cancer "Methylator Phenotype": Fact or Artifact?

    Directory of Open Access Journals (Sweden)

    Charles Anacleto

    2005-04-01

    Full Text Available It has been proposed that human colorectal tumors can be classified into two groups: one in which methylation is rare, and another with methylation of several loci associated with a "CpG island methylated phenotype (CIMP," characterized by preferential proximal location in the colon, but otherwise poorly defined. There is considerable overlap between this putative methylator phenotype and the well-known mutator phenotype associated with microsatellite instability (MSI. We have examined hypermethylation of the promoter region of five genes (DAPK, MGMT, hMLH1, p16INK4a, and p14ARF in 106 primary colorectal cancers. A graph depicting the frequency of methylated loci in the series of tumors showed a continuous, monotonically decreasing distribution quite different from the previously claimed discontinuity. We observed a significant association between the presence of three or more methylated loci and the proximal location of the tumors. However, if we remove from analysis the tumors with hMLH1 methylation or those with MSI, the significance vanishes, suggesting that the association between multiple methylations and proximal location was indirect due to the correlation with MSI. Thus, our data do not support the independent existence of the so-called methylator phenotype and suggest that it rather may represent a statistical artifact caused by confounding of associations.

  7. Girls Doing Science: A Case Study of Science Literacy in All-Female Middle Grade Classrooms

    Science.gov (United States)

    Faller, Susan Elisabeth

    In the face of low adolescent literacy rates (NCES, 2012), concerns about the nation's prospects of remaining competitive in science and technology (Hill, Corbett, & St. Rose, 2010), a persistent gender gap in science (NCES, 2012; Reilly, 2012), and the continued rollout of college- and career-ready standards, there is a need to focus on adolescent girls' science literacy. Such science literacy involves not only general knowledge about science, but also the ability to engage in the advanced reading and writing practices fundamental to doing science (Norris & Phillips, 2003). In this thesis, I present three articles with findings that respond to this need. They are the results of a multiple-case embedded (Yin, 2009) study that I conducted over the course of 7 months in four science classrooms (grades 5 through 8; 50 students) taught by a single teacher in a small all-female middle school. I collected in-depth data focused on science literacy from multiple sources, including (a) fieldnotes (Emerson, Fretz & Shaw, 2011), (b) videorecorded classroom observations (102 classes, 113 hours, recorded on 29 days), (c) a survey of all students, (d) semi-structured interviews with the subsample of 12 focal students (ranging from 18 to 37 minutes) and (e) photographs of classroom artifacts and student work. In the first article, I provide a window into standard literacy practices in science classrooms by examining the reading and writing genres to which students are exposed. In the second article, I examine how a teacher's language and instructional practices within her classrooms, and popular images of science from the world beyond their classrooms might shape adolescent girls' science identities. Finally, in the third article, I explore different aspects of science identity using the words of three case study students. Taken together, these studies fill gaps in the literature by investigating science literacy in an understudied context, all-female classrooms. In addition

  8. An observer model for quantifying panning artifacts in digital pathology

    Science.gov (United States)

    Avanaki, Ali R. N.; Espig, Kathryn S.; Xthona, Albert; Lanciault, Christian; Kimpe, Tom R. L.

    2017-03-01

    Typically, pathologists pan from one region of a slide to another, choosing areas of interest for closer inspection. Due to finite frame rate and imperfect zero-order hold reconstruction (i.e., the non-zero time to reach the target brightness after a change in pixel drive), panning in whole slide images (WSI) cause visual artifacts. It is important to study the impact of such artifacts since research suggests that 49% of navigation is conducted in low-power/overview with digital pathology (Molin et al., Histopathology 2015). In this paper, we explain what types of medical information may be harmed by panning artifacts, propose a method to simulate panning artifacts, and design an observer model to predict the impact of panning artifacts on typical human observers' performance in basic diagnostically relevant visual tasks. The proposed observer model is based on derivation of perceived object border maps from luminance and chrominance information and may be tuned to account for visual acuity of the human observer to be modeled. Our results suggest that increasing the contrast (e.g., using a wide gamut display) with a slow response panel may not mitigate the panning artifacts which mostly affect visual tasks involving spatial discrimination of objects (e.g., normal vs abnormal structure, cell type and spatial relationships between them, and low-power nuclear morphology), and that the panning artifacts worsen with increasing panning speed. The proposed methods may be used as building blocks in an automatic WSI quality assessment framework.

  9. Motion artifact detection in four-dimensional computed tomography images

    Science.gov (United States)

    Bouilhol, G.; Ayadi, M.; Pinho, R.; Rit, S.; Sarrut, D.

    2014-03-01

    Motion artifacts appear in four-dimensional computed tomography (4DCT) images because of suboptimal acquisition parameters or patient breathing irregularities. Frequency of motion artifacts is high and they may introduce errors in radiation therapy treatment planning. Motion artifact detection can be useful for image quality assessment and 4D reconstruction improvement but manual detection in many images is a tedious process. We propose a novel method to evaluate the quality of 4DCT images by automatic detection of motion artifacts. The method was used to evaluate the impact of the optimization of acquisition parameters on image quality at our institute. 4DCT images of 114 lung cancer patients were analyzed. Acquisitions were performed with a rotation period of 0.5 seconds and a pitch of 0.1 (74 patients) or 0.081 (40 patients). A sensitivity of 0.70 and a specificity of 0.97 were observed. End-exhale phases were less prone to motion artifacts. In phases where motion speed is high, the number of detected artifacts was systematically reduced with a pitch of 0.081 instead of 0.1 and the mean reduction was 0.79. The increase of the number of patients with no artifact detected was statistically significant for the 10%, 70% and 80% respiratory phases, indicating a substantial image quality improvement.

  10. Adiabatic Low-Pass J Filters for Artifact Suppression in Heteronuclear NMR

    DEFF Research Database (Denmark)

    Meier, Sebastian; Benie, Andrew J; Duus, Jens Øllgaard

    2009-01-01

    NMR artifact purging: Modern NMR experiments depend on efficient coherence transfer pathways for their sensitivity and on suppression of undesired pathways leading to artifacts for their spectral clarity. A novel robust adiabatic element suppresses hard-to-get-at artifacts.......NMR artifact purging: Modern NMR experiments depend on efficient coherence transfer pathways for their sensitivity and on suppression of undesired pathways leading to artifacts for their spectral clarity. A novel robust adiabatic element suppresses hard-to-get-at artifacts....

  11. Automatic correction of dental artifacts in PET/MRI

    DEFF Research Database (Denmark)

    Ladefoged, Claes N.; Andersen, Flemming L.; Keller, Sune

    2015-01-01

    A challenge when using current magnetic resonance (MR)-based attenuation correction in positron emission tomography/MR imaging (PET/MRI) is that the MRIs can have a signal void around the dental fillings that is segmented as artificial air-regions in the attenuation map. For artifacts connected...... air-regions by first using a template of artifact regions, and second, representing the artifact regions with a combination of active shape models and k-nearest-neighbors. The accuracy of the combined method has been evaluated using 25 18 F-fluorodeoxyglucose PET/MR patients. Results showed...

  12. Towards a concept of community artifact ecology in HCI?

    DEFF Research Database (Denmark)

    Saad-Sulonen, Joanna; Korsgaard, Henrik

    or workplaces do. This has implications on understanding how to research and design HCI for communities but also on refining the ecological perspective in HCI. We look in particular at examples from preliminary research on a local self-organised urban community and discuss what existing concepts in the ecology......In this paper we introduce the concept of community artifact ecology. We argue that taking a community perspective on the concept of artifact ecologies is relevant in HCI because communities are also dealing with multitudes of artifacts, in ways di↵erent that individuals, organizations...

  13. An assessment of mathematics classroom teaching- learning ...

    African Journals Online (AJOL)

    Data about the learning environment in mathematics classroom was collected using the Constructivist Learning Environment Survey (CLES). The CLES consists of five dimensions (scales): personal relevance, mathematical uncertainty, shared control, critical voice, and student negotiation, each scale having six items.

  14. Pay It Forward: Teacher Candidates’ Use of Historical Artifacts to Invigorate K-12 History Instruction

    Directory of Open Access Journals (Sweden)

    Scott M. Waring,

    2015-11-01

    Full Text Available The history education literature is replete with a call to help teachers understand that history should be taught as being inquiry-based and interpretive. We are encouraged, and rightfully so, to do history, to perform history, to do democracy, and to motivate students for inquiry and action by using primary sources. The authors developed a unit of study for history and social studies teacher candidates that would address several issues: (a motivate and inspire future teachers to use inquiry as a tool to build K-12 students’ historical understanding and facilitate purposeful utilization of artifacts with ease; (b help future teachers increase their knowledge of local history; and (c present a unit that could be easily used in a secondary history course and, with some modifications, could be adapted for elementary and middle school history classrooms. The assignment was named Pay it Forward: Invigorating Instruction through Local History. This multifaceted assignment included the development of a lesson plan that would (a demonstrate a robust understanding of engaging students in historical inquiry and local history, and (b focus on an artifact that the teacher candidate would find as part of the investigation. The majority of the teacher candidates in this study did show evidence of, albeit limited at times, designing curriculum that encouraged K-12 students to engage in historical inquiry. Making the bridge between theory and practice, or showing evidence of learning from the methods courses, was clearly evident across the lesson plans.

  15. Artifact-based reflective interviews for identifying pragmatic epistemological resources

    Science.gov (United States)

    Shubert, Christopher Walden

    Physics Education Research studies the science of teaching and learning physics. The process of student learning is complex, and the factors that affect it are numerous. Describing students' understanding of physics knowledge and reasoning is the basis for much productive research; however, such research fails to account for certain types of student learning difficulties. In this dissertation, I explore one source of student difficulty: personal epistemology, students' ideas about knowledge and knowing. Epistemology traditionally answers three questions: What is knowledge? How is knowledge created? And, how do we know what we know? An individual's responses to these questions can affect learning in terms of how they approach tasks involving the construction and application of knowledge. The key issue addressed in this dissertation is the effect of methodological choices on the validity and reliability of claims concerning personal epistemology. My central concern is contextual validity, how what is said about one's epistemology is not identical to how one behaves epistemologically. In response to these issues, I present here a new methodology for research on student epistemology: video artifact-based reflective interview protocols. These protocols begin with video taping students in their natural classroom activities, and then asking the participants epistemological questions immediately after watching selected scenes from their activity, contextually anchoring them in their actual learning experience. The data from these interviews is viewed in the framework of Epistemological Resource Theory, a framework of small bits of knowledge whose coordination in a given context is used to describe personal epistemology. I claim that the privileged data from these interviews allows detailed epistemological resources to be identified, and that these resources can provide greater insight into how student epistemologies are applied in learning activities. This research

  16. Statistical characteristics of streak artifacts on CT images: Relationship between streak artifacts and mA s values

    Energy Technology Data Exchange (ETDEWEB)

    Imai, Kuniahru; Ikeda, Mitsuru; Enchi, Yukihiro; Niimi, Takanaga [Department of Radiological Technology, Nagoya University School of Health Sciences, 1-20 Daikominami 1-chome, Higashi-ku, Nagoya, 461-8673 (Japan); Department of Radiology, Osaka University Hospital, 2-15 Yamadaoka, Suita, Osaka, 565-0871 (Japan); Department of Radiological Technology, Nagoya University School of Health Sciences, 1-20 Daikominami 1-chome, Higashi-ku, Nagoya 461-8673 (Japan)

    2009-02-15

    The purpose of this study is to investigate how streak artifacts on computed tomography (CT) images vary with reduction in radiation doses by assessing the quantitative relationship between the streak artifacts and milliampere-time product (mA s) values. A commercially available chest phantom was used to measure the streak artifacts on the CT images obtained using a 4- and 16-multidetector-row helical CT scanners with various mA s values at a constant tube voltage of 120 kVp. The cardiac slice image was employed as a target image for evaluating the streak artifacts on the CT image. Eighty parallel line segments with a length of 20 pixels were placed perpendicular to numerous streak artifacts on the cardiac slice image, and the largest difference between adjacent CT values in each of the 80 CT-value profiles of these line segments was employed as a feature variable of streak artifacts; these feature variables have been analyzed by the extreme value theory. The largest difference between adjacent CT values in each CT-value profile can be statistically modeled by a Gumbel distribution. Further, the maximum level of streak artifacts on CT images that will be tolerated for clinical use and low-dose CT screening examination was expected to be estimated using the location parameter in the Gumbel distribution.

  17. Surveying the experiences and perceptions of undergraduate nursing students of a flipped classroom approach to increase understanding of drug science and its application to clinical practice.

    Science.gov (United States)

    Hanson, Julie

    2016-01-01

    Patient harm from medication error is a significant issue. Individual failures by health professionals including knowledge deficits and poor communication have been identified as increasing the likelihood of medication administration errors. In Australia, the National Strategy for Quality Use of Medicines in 2002 compels health professionals to have the knowledge and skills to use medicines safely and effectively. This paper examines nursing students' perceptions of the effectiveness of a flipped classroom approach to increase understanding of pharmacology principles and the application of this knowledge to medication practice. An internet-based self-completion questionnaire was used in 2013 (n = 26) after the flipped classroom approach was implemented, and pre- (n = 6) and post-flipping (n = 25) in 2014. Students who engaged with digitally recorded lectures (eLectures) prior to face-to-face workshops stated that they had greater understanding of the subject and enhanced critical thinking skills. The replay function of the eLecture was perceived by some students as most beneficial to independent learning. However, for some students, time constraints meant that they relied on eLectures alone, while others preferred traditional teaching methods. Although limited by sample size and potential participant bias, the results provide insights about the flipped classroom experience from a student perspective. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Cultural Artifact Detection in Long Wave Infrared Imagery.

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Dylan Zachary [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Craven, Julia M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ramon, Eric [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-01-01

    Detection of cultural artifacts from airborne remotely sensed data is an important task in the context of on-site inspections. Airborne artifact detection can reduce the size of the search area the ground based inspection team must visit, thereby improving the efficiency of the inspection process. This report details two algorithms for detection of cultural artifacts in aerial long wave infrared imagery. The first algorithm creates an explicit model for cultural artifacts, and finds data that fits the model. The second algorithm creates a model of the background and finds data that does not fit the model. Both algorithms are applied to orthomosaic imagery generated as part of the MSFE13 data collection campaign under the spectral technology evaluation project.

  19. Metal artifact reduction based on the combined prior image

    CERN Document Server

    Zhang, Yanbo

    2014-01-01

    Metallic implants introduce severe artifacts in CT images, which degrades the image quality. It is an effective method to reduce metal artifacts by replacing the metal affected projection with the forward projection of a prior image. How to find a good prior image is the key of this class methods, and numerous algorithms have been proposed to address this issue recently. In this work, by using image mutual correlation, pixels in the original reconstructed image or linear interpolation corrected image, which are less affected by artifacts, are selected to build a combined image. Thereafter, a better prior image is generated from the combined image by using tissue classification. The results of three patients' CT images show that the proposed method can reduce metal artifacts remarkably.

  20. Ring artifacts correction in compressed sensing tomographic reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Paleo, Pierre, E-mail: pierre.paleo@esrf.fr [ESRF, 71 Avenue des Martyrs, 38000 Grenoble (France); Université de Grenoble, Gipsa-Lab, 11 Rue des Mathématiques, 38400 Saint-Martin-d’Hères (France); Mirone, Alessandro, E-mail: pierre.paleo@esrf.fr [ESRF, 71 Avenue des Martyrs, 38000 Grenoble (France)

    2015-07-14

    The formalism of iterative tomographic reconstruction with sparsity inducing penalty is extended to enable ring artifacts correction. Ring artifacts are a very common problem in tomographic reconstruction, and numerous methods exist to either pre-process the sinogram or correct the reconstructed slice. A novel approach to perform the correction as part of the reconstruction process is presented. It is shown that for iterative techniques, which amount to optimizing an objective function, the ring artifacts correction can be easily integrated in the formalism, enabling simultaneous slice reconstruction and ring artifacts correction. This method is tested and compared with mainstream correction techniques for both simulated and experimental data. Results show that the correction is efficient, especially for undersampled datasets. This technique is included in the PyHST2 code which is used at the European Synchrotron Radiation Facility for tomographic reconstruction.

  1. Smart Classroom

    Science.gov (United States)

    Kelly, Rhea, Ed.

    2006-01-01

    What makes a classroom "smart"? Presentation technologies such as projectors, document cameras, and LCD panels clearly fit the bill, but when considering other technologies for teaching, learning, and developing content, the possibilities become limited only by the boundaries of an institution's innovation. This article presents 32 best practices…

  2. Classroom Antarctica

    Science.gov (United States)

    Gozzard, David

    Australian company Antarctica Flights runs summer sightseeing trips out of Australian capital cities to tour the Antarctic coast. The Laby Foundation of the University of Melbourne, through its "Classroom Antarctica" program, sponsored Kent Street High School science teacher, Ms Suzy Urbaniak and 18 of her students to take the trip, to…

  3. Virtual Classroom

    DEFF Research Database (Denmark)

    Christensen, Ove

    2013-01-01

    In the Scandinavian countries: Sweden, Norway and Denmark, the project GNU (Grænseoverskridende Nordisk Undervisning, i.e. Transnational Nordic Teaching) is experimenting with ways of conducting teaching across the borders in the elementary schools. The cloud classes are organised with one class ...... and benefits in regard to learning and pedagogy with virtual classroom....

  4. Science Teacher Beliefs and Classroom Practice Related to Constructivism in Different School Settings

    Science.gov (United States)

    Savasci, Funda; Berlin, Donna F.

    2012-01-01

    Science teacher beliefs and classroom practice related to constructivism and factors that may influence classroom practice were examined in this cross-case study. Data from four science teachers in two schools included interviews, demographic questionnaire, Classroom Learning Environment Survey (preferred/perceived), and classroom observations and…

  5. Mitigation of artifacts in rtm with migration kernel decomposition

    KAUST Repository

    Zhan, Ge

    2012-01-01

    The migration kernel for reverse-time migration (RTM) can be decomposed into four component kernels using Born scattering and migration theory. Each component kernel has a unique physical interpretation and can be interpreted differently. In this paper, we present a generalized diffraction-stack migration approach for reducing RTM artifacts via decomposition of migration kernel. The decomposition leads to an improved understanding of migration artifacts and, therefore, presents us with opportunities for improving the quality of RTM images.

  6. Myocardial imaging artifacts caused by mitral valve annulus calcification

    Energy Technology Data Exchange (ETDEWEB)

    Wagoner, L.E.; Movahed, A.; Reeves, W.C. (East Carolina Univ. School of Medicine, Greenville, NC (USA))

    1991-02-01

    Knowledge of imaging artifact of myocardial perfusion studies with thallium-201 is critical for improving the diagnostic accuracy of coronary artery disease. Three patients are described who underwent exercise or pharmacologic stress thallium-201 imaging studies and had a moderate, fixed myocardial perfusion defect (scar) involving the posterolateral and inferoposterior walls of the left ventricle. This was an imaging artifact caused by a heavily calcified mitral valve annulus.

  7. Adaptive cancellation of motion artifact in wearable biosensors.

    Science.gov (United States)

    Yousefi, Rasoul; Nourani, Mehrdad; Panahi, Issa

    2012-01-01

    The performance of wearable biosensors is highly influenced by motion artifact. In this paper, a model is proposed for analysis of motion artifact in wearable photoplethysmography (PPG) sensors. Using this model, we proposed a robust real-time technique to estimate fundamental frequency and generate a noise reference signal. A Least Mean Square (LMS) adaptive noise canceler is then designed and validated using our synthetic noise generator. The analysis and results on proposed technique for noise cancellation shows promising performance.

  8. Laser cleaning as a conservation technique for corroded metal artifacts

    OpenAIRE

    Koh, Yang Sook

    2006-01-01

    Preservation of cultural property for the future is one of the most important activities of our society. The information which we can gather from such materials is a valuable key to understanding the past. Conservation is a process which includes a range of different treatments. Cleaning is one of the critical steps of the conservation process and involves stabilizing the material and the exposure of hidden details on the surface of the artifact in question. As the artifacts are often fragile...

  9. Ortho projection and drawing for archeological artifacts using CCD camera

    Science.gov (United States)

    Yokoyama, Hiroshi; Chikatsu, Hirofumi; Miyatsuka, Yoshito

    1995-09-01

    In the compilation of archival records for archeological artifacts, true orthographic drawings of these artifacts have to be drawn by the archeologists themselves or part-timer, expending a great deal of time, labor, and skills. This paper describes the real time orthographic drawing system using a CCD camera. Finally, it demonstrates real time orthographic drawing results for Jomon pottery by using this system instead of the manual method which requires 3-4 hours.

  10. Dual energy approach for cone beam artifacts correction

    Science.gov (United States)

    Han, Chulhee; Choi, Shinkook; Lee, Changwoo; Baek, Jongduk

    2017-03-01

    Cone beam computed tomography systems generate 3D volumetric images, which provide further morphological information compared to radiography and tomosynthesis systems. However, reconstructed images by FDK algorithm contain cone beam artifacts when a cone angle is large. To reduce the cone beam artifacts, two-pass algorithm has been proposed. The two-pass algorithm considers the cone beam artifacts are mainly caused by high density materials, and proposes an effective method to estimate error images (i.e., cone beam artifacts images) by the high density materials. While this approach is simple and effective with a small cone angle (i.e., 5 - 7 degree), the correction performance is degraded as the cone angle increases. In this work, we propose a new method to reduce the cone beam artifacts using a dual energy technique. The basic idea of the proposed method is to estimate the error images generated by the high density materials more reliably. To do this, projection data of the high density materials are extracted from dual energy CT projection data using a material decomposition technique, and then reconstructed by iterative reconstruction using total-variation regularization. The reconstructed high density materials are used to estimate the error images from the original FDK images. The performance of the proposed method is compared with the two-pass algorithm using root mean square errors. The results show that the proposed method reduces the cone beam artifacts more effectively, especially with a large cone angle.

  11. Detection of eye blink artifacts from single prefrontal channel electroencephalogram.

    Science.gov (United States)

    Chang, Won-Du; Cha, Ho-Seung; Kim, Kiwoong; Im, Chang-Hwan

    2016-02-01

    Eye blinks are one of the most influential artifact sources in electroencephalogram (EEG) recorded from frontal channels, and thereby detecting and rejecting eye blink artifacts is regarded as an essential procedure for improving the quality of EEG data. In this paper, a novel method to detect eye blink artifacts from a single-channel frontal EEG signal was proposed by combining digital filters with a rule-based decision system, and its performance was validated using an EEG dataset recorded from 24 healthy participants. The proposed method has two main advantages over the conventional methods. First, it uses single-channel EEG data without the need for electrooculogram references. Therefore, this method could be particularly useful in brain-computer interface applications using headband-type wearable EEG devices with a few frontal EEG channels. Second, this method could estimate the ranges of eye blink artifacts accurately. Our experimental results demonstrated that the artifact range estimated using our method was more accurate than that from the conventional methods, and thus, the overall accuracy of detecting epochs contaminated by eye blink artifacts was markedly increased as compared to conventional methods. The MATLAB package of our library source codes and sample data, named Eyeblink Master, is open for free download. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Artifact removal from EEG signals using adaptive filters in cascade

    Science.gov (United States)

    Garcés Correa, A.; Laciar, E.; Patiño, H. D.; Valentinuzzi, M. E.

    2007-11-01

    Artifacts in EEG (electroencephalogram) records are caused by various factors, like line interference, EOG (electro-oculogram) and ECG (electrocardiogram). These noise sources increase the difficulty in analyzing the EEG and to obtaining clinical information. For this reason, it is necessary to design specific filters to decrease such artifacts in EEG records. In this paper, a cascade of three adaptive filters based on a least mean squares (LMS) algorithm is proposed. The first one eliminates line interference, the second adaptive filter removes the ECG artifacts and the last one cancels EOG spikes. Each stage uses a finite impulse response (FIR) filter, which adjusts its coefficients to produce an output similar to the artifacts present in the EEG. The proposed cascade adaptive filter was tested in five real EEG records acquired in polysomnographic studies. In all cases, line-frequency, ECG and EOG artifacts were attenuated. It is concluded that the proposed filter reduces the common artifacts present in EEG signals without removing significant information embedded in these records.

  13. Perceptions of Mobile Phones in College Classrooms: Ringing, Cheating, and Classroom Policies

    Science.gov (United States)

    Campbell, Scott W.

    2006-01-01

    The purpose of this study was to explore some of the challenges associated with mobile phones in college classrooms. A sample of faculty and students was surveyed to assess the extent to which the technology is considered a serious source of distraction in the classroom, concerns about use of the technology for cheating, and attitudes about…

  14. CLASSROOM MANAGEMENT

    OpenAIRE

    SAADAT BONAB, Habib; ESSMATI, Alavieh

    2015-01-01

    Abstract. The students’ greatest need both in and outside the classroom is to learn. Humans are intelligent beings who live in a complex, interdependent world in which their success or failure as individuals depends greatly on what they know about that word and about themselves. People need to learn and to develop the discipline needed to learn, and in most modern society's schools are the institutions in which young people focus their attention on this important task. Therefore, any class in...

  15. A case study of the impact of a reformed science curriculum on student attitudes and learning in a secondary physics classroom

    Science.gov (United States)

    Molotsky, Gregg Jeremy

    2011-12-01

    This case study examined the impact of the application of an inquiry-based concept related physics curriculum on student attitudes and learning in a secondary physics classroom in southern New Jersey. Students who had previously used a traditional physics curriculum were presented with a 10 week inquiry-based concept related physics curriculum on electricity and magnetism. The study utilized observations, a pre/post attitudinal survey, interviews of students and teachers about their perceptions of the inquiry-based curriculum, and artifact analysis of student work. The results showed a positive change in students' attitude in four of the eight categories designated in the CLASS survey. The observations, interviews and artifact analysis revealed that students were more engaged in learning physics through their discoveries in relating physics concepts to real world applications, a growing personal interest in the value and relevance of science learning and a disconnect between the students' and teacher's perceptions about what is important in learning physics. The study recommends that the rigidity of a traditional physics curriculum with its emphasis on covering many topics and the mathematical language of physics should give way to more inquiry-based concept related curriculum that incorporates exploration, hands-on inquiry activities, and real world connections. The research supports that better efforts be made to familiarize current and future secondary physics educators with the body of research that establishes the benefits of inquiry-based concept related curriculum on physics students.

  16. Out of Classroom Instruction in the Flipped Classroom

    DEFF Research Database (Denmark)

    Triantafyllou, Evangelia; Timcenko, Olga

    2015-01-01

    This article presents experiences and student perceptions on the introduction of the flipped classroom model in two consecutive semesters at Media Technology department of Aalborg University, Copenhagen, Denmark. We introduced the flipped instruction model to a statistics course and a mathematics...... workshop. We collected data by two online survey studies, which show support for student perceptions that out-of-classroom instruction with online resources enhances learning, by providing visual and in depth explanations, and can engage the learner. However, students stated that they miss just......-in-time explanations when learning with online resources and they questioned the quality and validity of some of them. Based on these findings and our own experience, we discuss requirements for resources and activities in flipped classrooms in order for the student to engage and learn. Finally, we present a framework...

  17. All Together Now: Measuring Staff Cohesion in Special Education Classrooms

    Science.gov (United States)

    Kratz, Hilary E.; Locke, Jill; Piotrowski, Zinnia; Ouellette, Rachel R.; Xie, Ming; Stahmer, Aubyn C.; Mandell, David S.

    2015-01-01

    This study sought to validate a new measure, the Classroom Cohesion Survey (CCS), designed to examine the relationship between teachers and classroom assistants in autism support classrooms. Teachers, classroom assistants, and external observers showed good inter-rater agreement on the CCS and good internal consistency for all scales. Simple factor structures were found for both teacher- and classroom assistant–rated scales, with one-factor solutions for both scales. Paired t tests revealed that on average, classroom assistants rated classroom cohesion stronger than teachers. The CCS may be an effective tool for measuring cohesion between classroom staff and may have an important impact on various clinical and implementation outcomes in school settings. PMID:26213443

  18. An Avenue for Challenging Sexism: Examining the High School Sociology Classroom

    Science.gov (United States)

    Stevens, Kaylene Mae; Martell, Christopher C.

    2016-01-01

    In this interpretative qualitative study, the researchers investigated the beliefs and practices of six high school sociology teachers in relation to the teaching of gender. Using a feminist lens, this study employed mixed methods, analyzing teacher interviews, observations, and classroom artifacts. The results showed that the teachers viewed…

  19. Autorretratos en la Clase de Espanol (Self-Portraits in Spanish Classroom)

    Science.gov (United States)

    Palos, Jose M.

    2007-01-01

    Foreign language teachers know the benefits of bringing art into their classrooms. Works of art are cultural artifacts that convey rich cultural perspectives. Integrating art into the foreign language curriculum facilitates visual learning, providing valuable opportunities to help the students develop visual thinking. Art can also be an effective…

  20. Technology-Supported Orchestration Matters: Outperforming Paper-Based Scripting in a Jigsaw Classroom

    Science.gov (United States)

    Balestrini, Mara; Hernandez-Leo, Davinia; Nieves, Raul; Blat, Josep

    2014-01-01

    Under the umbrella of ubiquitous technologies, many computational artifacts have been designed to enhance the learning experience in physical settings such as classrooms or playgrounds, but few of them focus on aiding orchestration. This paper presents a systematic evaluation of the signal orchestration system (SOS) used by students for a jigsaw…

  1. Motion Artifact in the MR imaging of temporomandibular disorders

    Energy Technology Data Exchange (ETDEWEB)

    Tamamura, Kiyoharu; Miyajima, Hisashi; Nihei, Yoshinobu; Nemoto, Ryuichi; Ohno, Tomoya [Ohu Univ., Koriyama, Fukushima (Japan). School of Dentistry

    1997-09-01

    Recently, magnetic resonance imaging (MRI) is indispensable for the diagnosis of temporomandibular disorders (TMD). Motion Artifacts of MRI occur more frequently than in other conventional methods, because it takes a long time to obtain the images. This paper reported on Motion Artifacts on MRI. MRI studies of 232 temporomandibular joints were performed in 116 patients with TMD by using a 0.5-T magnetic resonance (MR) scanner, with spin echo sequence: protondensity-weighted. And we took MRI slices at opening phase and closing phase. So 232 slices were gathered and we evaluated clinically the incidence of Motion Artifacts, that is to say, double and multiple images and other factors. The 103 slices in 56 patients showed Motion Artifacts. There is no significant difference between sexes. By age group, those in their teens were most frequent, followed by those in their fifties, forties, thirties and twenties. Also the same results were obtained for double image and multiple image. Incidence of Motion Artifact was most frequent at the opening phase. There is no significant difference between double and multiple image. (author)

  2. Artifact detection in electrodermal activity using sparse recovery

    Science.gov (United States)

    Kelsey, Malia; Palumbo, Richard Vincent; Urbaneja, Alberto; Akcakaya, Murat; Huang, Jeannie; Kleckner, Ian R.; Barrett, Lisa Feldman; Quigley, Karen S.; Sejdic, Ervin; Goodwin, Matthew S.

    2017-05-01

    Electrodermal Activity (EDA) - a peripheral index of sympathetic nervous system activity - is a primary measure used in psychophysiology. EDA is widely accepted as an indicator of physiological arousal, and it has been shown to reveal when psychologically novel events occur. Traditionally, EDA data is collected in controlled laboratory experiments. However, recent developments in wireless biosensing have led to an increase in out-of-lab studies. This transition to ambulatory data collection has introduced challenges. In particular, artifacts such as wearer motion, changes in temperature, and electrical interference can be misidentified as true EDA responses. The inability to distinguish artifact from signal hinders analyses of ambulatory EDA data. Though manual procedures for identifying and removing EDA artifacts exist, they are time consuming - which is problematic for the types of longitudinal data sets represented in modern ambulatory studies. This manuscript presents a novel technique to automatically identify and remove artifacts in EDA data using curve fitting and sparse recovery methods. Our method was evaluated using labeled data to determine the accuracy of artifact identification. Procedures, results, conclusions, and future directions are presented.

  3. DC artifact correction for arbitrary phase-cycling sequence.

    Science.gov (United States)

    Han, Paul Kyu; Park, HyunWook; Park, Sung-Hong

    2017-05-01

    In magnetic resonance imaging (MRI), a non-zero offset in the receiver baseline signal during acquisition results in a bright spot or a line artifact in the center of the image known as a direct current (DC) artifact. Several methods have been suggested in the past for the removal or correction of DC artifacts in MR images, however, these methods cannot be applied directly when a specific phase-cycling technique is used in the imaging sequence. In this work, we proposed a new, simple technique that enables correction of DC artifacts for any arbitrary phase-cycling imaging sequences. The technique is composed of phase unification, DC offset estimation and correction, and phase restoration. The feasibility of the proposed method was demonstrated via phantom and in vivo experiments with a multiple phase-cycling balanced steady-state free precession (bSSFP) imaging sequence. Results showed successful removal of the DC artifacts in images acquired using bSSFP with phase-cycling angles of 0°, 90°, 180°, and 270°, indicating potential feasibility of the proposed method to any imaging sequence with arbitrary phase-cycling angles. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Insect Artifacts Are More than Just Altered Bloodstains.

    Science.gov (United States)

    Rivers, David; Geiman, Theresa

    2017-03-28

    The bases for forensic entomology are that insects and their arthropod relatives can serve as evidence in criminal, medical and civil legal matters. However, some of the very same species that provide utility to legal investigations can also complicate crime scenes by distorting existing body fluid evidence (e.g., bloodstains, semen, saliva) and/or depositing artifacts derived from the insect alimentary canal at primary or secondary crime scenes. The insect contaminants are referred to as insect stains, artifacts, specks or spots, and are most commonly associated with human bloodstains. This review will discuss the different types of insect artifacts that have been described from crime scenes and laboratory experiments, as well as examine insect contaminates (non-blood based artifacts, transfer patterns, meconium, and larval fluids) that have received little research or case attention. Methods currently used for distinguishing insect stains from human body fluids will also be discussed and compared to presumptive tests used for identification of human body fluids. Since all available methods have severe limitations, areas of new research will be identified for the purpose of development of diagnostic techniques for detection of insect artifacts.

  5. Pulmonary MRA: Differentiation of pulmonary embolism from truncation artifact

    Science.gov (United States)

    Bannas, Peter; Schiebler, Mark L; Motosugi, Utaroh; François, Christopher J; Reeder, Scott B; Nagle, Scott K

    2015-01-01

    Purpose Truncation artifact (Gibbs ringing) causes central signal drop within vessels in pulmonary MRA that can be mistaken for emboli, reducing the diagnostic accuracy for pulmonary embolism (PE). We propose a quantitative approach to differentiate truncation artifact from PE. Methods Twenty-eight patients who underwent pulmonary CTA for suspected PE were recruited for pulmonary MRA. Signal intensity drops within pulmonary arteries that persisted on both arterial-phase and delayed-phase MRA were identified. The percent signal loss between the vessel lumen and central drop was measured. CTA served as the reference standard for presence of pulmonary emboli. Results A total of 65 signal intensity drops were identified on MRA. 48 (74%) of these were artifact and 17 (26%) were PE, as confirmed by CTA. Truncation artifacts had a significantly lower median signal drop than PE at both arterial-phase (26% [range 12–58%] vs. 85% [range 53–91%]) and at delayed-phase MRA (26% [range 11–55%] vs. 77% [range 47–89%]), p90% specificity. Conclusion Quantitative signal drop is an objective tool to help differentiate truncation artifact and pulmonary embolism in pulmonary MRA. PMID:24863886

  6. Removing speech artifacts from electroencephalographic recordings during overt picture naming.

    Science.gov (United States)

    Porcaro, Camillo; Medaglia, Maria Teresa; Krott, Andrea

    2015-01-15

    A number of electroencephalography (EEG) studies have investigated the time course of brain activation during overt word production. The interpretation of their results is complicated by the fact that articulatory movements may mask the cognitive components of interest. The first aim of the present study was to investigate when speech artifacts occur during word production planning and what effects they have on the spatio-temporal neural activation pattern. The second aim was to propose a new method that strongly attenuates speech artifacts during overt picture naming and to compare it with existing methods. EEG and surface electromyograms (EMGs) of the lips were recorded while participants overtly named pictures in a picture-word interference paradigm. The comparison of the raw data with lip EMG and the comparison of source localizations of raw and corrected EEG data showed that speech artifacts occurred mainly from ~400 ms post-stimulus onset, but some earlier artifacts mean that they occur much earlier than hitherto assumed. We compared previously used methods of speech artifacts removal (SAR) with a new method, which is based on Independent Component Analysis (SAR-ICA). Our new method clearly outperformed other methods. In contrast to other methods, there was only a weak correlation between the lip EMG and the corrected data by SAR-ICA. Also, only the data corrected with our method showed activation of cerebral sources consistent with meta-analyses of word production. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Relevance of motion artifact in electromyography recordings during vibration treatment.

    Science.gov (United States)

    Fratini, Antonio; Cesarelli, Mario; Bifulco, Paolo; Romano, Maria

    2009-08-01

    Electromyography readings (EMGs) from quadriceps of fifteen subjects were recorded during whole body vibration treatment at different frequencies (10-50 Hz). Additional electrodes were placed on the patella to monitor the occurrence of motion artifact, triaxial accelerometers were placed onto quadriceps to monitor motion. Signal spectra revealed sharp peaks corresponding to vibration frequency and its harmonics, in accordance with the accelerometer data. EMG total power was compared to that associated with vibration harmonics narrow bands, before and during vibration. On average, vibration associated power resulted in only 3% (+/-0.9%) of the total power prior to vibration and 29% (+/-13.4%) during vibration. Often, studies employ surface EMG to quantitatively evaluate vibration evoked muscular activity and to set stimulation frequency. However, previous research has not accounted for motion artifacts. The data presented in this study emphasize the need for the removal of motion artifacts, as they consistently affect RMS estimation, which is often used as a concise muscle activity index during vibrations. Such artifacts, rather unpredictable in amplitude, might be the cause of large inter-study differences and must be eliminated before analysis. Motion artifact filtering will contribute to thorough and precise interpretation of neuromuscular response to vibration treatment.

  8. Artifacts by dental materials on magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Hyun Sook; Choi, Deuk Lin; Kim, Ki Jung [Soonchunhyang University Hospital, Asan (Korea, Republic of); Suh, Won Hyuck [Korea University Hospital, Seoul (Korea, Republic of)

    1992-05-15

    Magnetic resonance imaging (MRI) has proved to be a valuable method for evaluation of the head and neck. Unfortunately, metallic devices associated with certain dental fillings and appliances often cause variable artifacts that can obscure normal or pathologic conditions on MR and computed tomography. In this work, we assessed the MR appearance of dental prosthetic materials in vitro and in vivo including precious alloys, nonprecions alloys, resin, amalgam and titanium alloy. For in vivo studies, these materials were placed in healthy volunteer's mouths and then images were assessed. Analysis of the appearance of shape and extent of artifact, and observed influence of these artifacts on the image interpretation at 0.2 Tesla permanent type MR scanner were valuated. Material used as temporary or permanent filling of crowns such as amalgam, precious alloy and, microfilled resin did not cause artifact on the image. The size of the artifact produced by the nonprecious alloys was influenced by the ferromagnetism of the object and the volume prosthesis, and was related to the scanning sequence. Nonprecious alloys produced minimal local signal distortion, where precious alloys, and dental resin had no effect on the MR images in vivo. These results were mainly from a low field strength MR scanner used in this study.

  9. Automatic correction of dental artifacts in PET/MRI.

    Science.gov (United States)

    Ladefoged, Claes N; Andersen, Flemming L; Keller, Sune H; Beyer, Thomas; Law, Ian; Højgaard, Liselotte; Darkner, Sune; Lauze, Francois

    2015-04-01

    A challenge when using current magnetic resonance (MR)-based attenuation correction in positron emission tomography/MR imaging (PET/MRI) is that the MRIs can have a signal void around the dental fillings that is segmented as artificial air-regions in the attenuation map. For artifacts connected to the background, we propose an extension to an existing active contour algorithm to delineate the outer contour using the nonattenuation corrected PET image and the original attenuation map. We propose a combination of two different methods for differentiating the artifacts within the body from the anatomical air-regions by first using a template of artifact regions, and second, representing the artifact regions with a combination of active shape models and k-nearest-neighbors. The accuracy of the combined method has been evaluated using 25 [Formula: see text]-fluorodeoxyglucose PET/MR patients. Results showed that the approach was able to correct an average of [Formula: see text] of the artifact areas.

  10. Metal artifact reduction method using metal streaks image subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Pua, Rizza D.; Cho, Seung Ryong [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-04-15

    Many studies have been dedicated for metal artifact reduction (MAR); however, the methods are successful to varying degrees depending on situations. Sinogram in-painting, filtering, iterative method are some of the major categories of MAR. Each has its own merits and weaknesses. A combination of these methods or hybrid methods have also been developed to make use of the different benefits of two techniques and minimize the unfavorable results. Our method focuses on the in-paitning approach and a hybrid MAR described by Xia et al. Although in-painting scheme is an effective technique in reducing the primary metal artifacts, a major drawback is the reintroduction of new artifacts that can be caused by an inaccurate interpolation process. Furthermore, combining the segmented metal image to the corrected nonmetal image in the final step of a conventional inpainting approach causes an issue of incorrect metal pixel values. Our proposed method begins with a sinogram in-painting approach and ends with an image-based metal artifact reduction scheme. This work provides a simple, yet effective solution for reducing metal artifacts and acquiring the original metal pixel information. The proposed method demonstrated its effectiveness in a simulation setting. The proposed method showed image quality that is comparable to the standard MAR; however, quantitatively more accurate than the standard MAR.

  11. Medical image of the week: DBS polysomnogram artifact

    Directory of Open Access Journals (Sweden)

    Shetty S,

    2015-10-01

    Full Text Available A 79-year-old man with known Parkinson’s disease and status post deep brain stimulator (DBS implantation underwent an overnight polysomnogram for clinical suspicion of obstructive sleep apnea. Artifact was seen on the polysomnogram recording (Figures 1 & 2. Patient-related electrical artifacts may be seen from devices such as pacemakers, deep brain stimulators and vagal nerve simulators. Abrupt discontinuation of DBS is associated with a high likelihood of worsening of symptoms in patients with Parkinson’s disease (1. Patients with DBS are most commonly programmed in monopolar mode. Bipolar configuration, forms a short electrical dipole that affects a relatively smaller volume of tissue and generates far less artifact, suggesting that this may be an effective option in a Parkinsonian patient with indications for polysomnography (2.

  12. EEG artifact removal-state-of-the-art and guidelines.

    Science.gov (United States)

    Urigüen, Jose Antonio; Garcia-Zapirain, Begoña

    2015-06-01

    This paper presents an extensive review on the artifact removal algorithms used to remove the main sources of interference encountered in the electroencephalogram (EEG), specifically ocular, muscular and cardiac artifacts. We first introduce background knowledge on the characteristics of EEG activity, of the artifacts and of the EEG measurement model. Then, we present algorithms commonly employed in the literature and describe their key features. Lastly, principally on the basis of the results provided by various researchers, but also supported by our own experience, we compare the state-of-the-art methods in terms of reported performance, and provide guidelines on how to choose a suitable artifact removal algorithm for a given scenario. With this review we have concluded that, without prior knowledge of the recorded EEG signal or the contaminants, the safest approach is to correct the measured EEG using independent component analysis-to be precise, an algorithm based on second-order statistics such as second-order blind identification (SOBI). Other effective alternatives include extended information maximization (InfoMax) and an adaptive mixture of independent component analyzers (AMICA), based on higher order statistics. All of these algorithms have proved particularly effective with simulations and, more importantly, with data collected in controlled recording conditions. Moreover, whenever prior knowledge is available, then a constrained form of the chosen method should be used in order to incorporate such additional information. Finally, since which algorithm is the best performing is highly dependent on the type of the EEG signal, the artifacts and the signal to contaminant ratio, we believe that the optimal method for removing artifacts from the EEG consists in combining more than one algorithm to correct the signal using multiple processing stages, even though this is an option largely unexplored by researchers in the area.

  13. EEG Artifact Removal Using a Wavelet Neural Network

    Science.gov (United States)

    Nguyen, Hoang-Anh T.; Musson, John; Li, Jiang; McKenzie, Frederick; Zhang, Guangfan; Xu, Roger; Richey, Carl; Schnell, Tom

    2011-01-01

    !n this paper we developed a wavelet neural network. (WNN) algorithm for Electroencephalogram (EEG) artifact removal without electrooculographic (EOG) recordings. The algorithm combines the universal approximation characteristics of neural network and the time/frequency property of wavelet. We. compared the WNN algorithm with .the ICA technique ,and a wavelet thresholding method, which was realized by using the Stein's unbiased risk estimate (SURE) with an adaptive gradient-based optimal threshold. Experimental results on a driving test data set show that WNN can remove EEG artifacts effectively without diminishing useful EEG information even for very noisy data.

  14. Inter-deriving Semantic Artifacts for Object-Oriented Programming

    DEFF Research Database (Denmark)

    Danvy, Olivier; Johannsen, Jacob

    2008-01-01

    We present a new abstract machine for Abadi and Cardelli's untyped calculus of objects. What is special about this semantic artifact (i.e., man-made construct) is that is mechanically corresponds to both the reduction semantics (i.e., small-step operational semantics) and the natural semantics (i...... actual substitutions, we then represent object methods as closures and in the same inter-derivational spirit, we present three new semantic artifacts: a reduction semantics for a version of Abadi and Cardelli's untyped calculus of objects with explicit substitutions, an environment-based abstract machine...

  15. Frequency split metal artifact reduction (FSMAR) in computed tomography.

    Science.gov (United States)

    Meyer, Esther; Raupach, Rainer; Lell, Michael; Schmidt, Bernhard; Kachelrieß, Marc

    2012-04-01

    The problem of metal artifact reduction (MAR) is almost as old as the clinical use of computed tomography itself. When metal implants are present in the field of measurement, severe artifacts degrade the image quality and the diagnostic value of CT images. Up to now, no generally accepted solution to this issue has been found. In this work, a method based on a new MAR concept is presented: frequency split metal artifact reduction (FSMAR). It ensures efficient reduction of metal artifacts at high image quality with enhanced preservation of details close to metal implants. FSMAR combines a raw data inpainting-based MAR method with an image-based frequency split approach. Many typical methods for metal artifact reduction are inpainting-based MAR methods and simply replace unreliable parts of the projection data, for example, by linear interpolation. Frequency split approaches were used in CT, for example, by combining two reconstruction methods in order to reduce cone-beam artifacts. FSMAR combines the high frequencies of an uncorrected image, where all available data were used for the reconstruction with the more reliable low frequencies of an image which was corrected with an inpainting-based MAR method. The algorithm is tested in combination with normalized metal artifact reduction (NMAR) and with a standard inpainting-based MAR approach. NMAR is a more sophisticated inpainting-based MAR method, which introduces less new artifacts which may result from interpolation errors. A quantitative evaluation was performed using the examples of a simulation of the XCAT phantom and a scan of a spine phantom. Further evaluation includes patients with different types of metal implants: hip prostheses, dental fillings, neurocoil, and spine fixation, which were scanned with a modern clinical dual source CT scanner. FSMAR ensures sharp edges and a preservation of anatomical details which is in many cases better than after applying an inpainting-based MAR method only. In contrast

  16. Reaching the Millennial Generation in the Classroom

    Science.gov (United States)

    Kotz, Paul E.

    2016-01-01

    The millennial generation (Generation Y) is the age group of children born between 1982 and 2002. Students aged 15 to 16 were asked to answer questions regarding their classroom experience. Sixty eight students were asked to participate in the survey and 63 gave consent for their participation. A qualitative survey approach was used asking three…

  17. Metal artifacts in computed tomography for radiation therapy planning: dosimetric effects and impact of metal artifact reduction

    Science.gov (United States)

    Giantsoudi, Drosoula; De Man, Bruno; Verburg, Joost; Trofimov, Alexei; Jin, Yannan; Wang, Ge; Gjesteby, Lars; Paganetti, Harald

    2017-04-01

    A significant and increasing number of patients receiving radiation therapy present with metal objects close to, or even within, the treatment area, resulting in artifacts in computed tomography (CT) imaging, which is the most commonly used imaging method for treatment planning in radiation therapy. In the presence of metal implants, such as dental fillings in treatment of head-and-neck tumors, spinal stabilization implants in spinal or paraspinal treatment or hip replacements in prostate cancer treatments, the extreme photon absorption by the metal object leads to prominent image artifacts. Although current CT scanners include a series of correction steps for beam hardening, scattered radiation and noisy measurements, when metal implants exist within or close to the treatment area, these corrections do not suffice. CT metal artifacts affect negatively the treatment planning of radiation therapy either by causing difficulties to delineate the target volume or by reducing the dose calculation accuracy. Various metal artifact reduction (MAR) methods have been explored in terms of improvement of organ delineation and dose calculation in radiation therapy treatment planning, depending on the type of radiation treatment and location of the metal implant and treatment site. Including a brief description of the available CT MAR methods that have been applied in radiation therapy, this article attempts to provide a comprehensive review on the dosimetric effect of the presence of CT metal artifacts in treatment planning, as reported in the literature, and the potential improvement suggested by different MAR approaches. The impact of artifacts on the treatment planning and delivery accuracy is discussed in the context of different modalities, such as photon external beam, brachytherapy and particle therapy, as well as by type and location of metal implants.

  18. Metal artifacts in computed tomography for radiation therapy planning: dosimetric effects and impact of metal artifact reduction.

    Science.gov (United States)

    Giantsoudi, Drosoula; De Man, Bruno; Verburg, Joost; Trofimov, Alexei; Jin, Yannan; Wang, Ge; Gjesteby, Lars; Paganetti, Harald

    2017-04-21

    A significant and increasing number of patients receiving radiation therapy present with metal objects close to, or even within, the treatment area, resulting in artifacts in computed tomography (CT) imaging, which is the most commonly used imaging method for treatment planning in radiation therapy. In the presence of metal implants, such as dental fillings in treatment of head-and-neck tumors, spinal stabilization implants in spinal or paraspinal treatment or hip replacements in prostate cancer treatments, the extreme photon absorption by the metal object leads to prominent image artifacts. Although current CT scanners include a series of correction steps for beam hardening, scattered radiation and noisy measurements, when metal implants exist within or close to the treatment area, these corrections do not suffice. CT metal artifacts affect negatively the treatment planning of radiation therapy either by causing difficulties to delineate the target volume or by reducing the dose calculation accuracy. Various metal artifact reduction (MAR) methods have been explored in terms of improvement of organ delineation and dose calculation in radiation therapy treatment planning, depending on the type of radiation treatment and location of the metal implant and treatment site. Including a brief description of the available CT MAR methods that have been applied in radiation therapy, this article attempts to provide a comprehensive review on the dosimetric effect of the presence of CT metal artifacts in treatment planning, as reported in the literature, and the potential improvement suggested by different MAR approaches. The impact of artifacts on the treatment planning and delivery accuracy is discussed in the context of different modalities, such as photon external beam, brachytherapy and particle therapy, as well as by type and location of metal implants.

  19. THE DISABLED AND ART: SELECTED ARTIFACTS OF GHANAIAN ...

    African Journals Online (AJOL)

    THE DISABLED AND ART: SELECTED ARTIFACTS OF. GHANAIAN PHYSICALLY DISABLED ARTISTS AS A RE-. SOURCE FOR TEACHING AND LEARNING. P. Osei-Poku and B. Acheampong. Department of General Art Studies, KNUST, Kumasi, Ghana. ABSTRACT. Some disabled artists in Ghana exhibit a lot of rich ...

  20. Controlling simulations of human-artifact interaction with scenario bundles

    NARCIS (Netherlands)

    Van der Vegte, W.F.; Rusák, Z.

    2008-01-01

    We introduce a methodology for modeling and simulating fully virtual human-artifact systems, aiming to resolve two issues in virtual prototyping: (i) integration of distinct modeling and simulation approaches, and (ii) extending the deployability of simulations towards conceptual design. We are

  1. How Do Artifact Models Help Direct SPI Projects?

    DEFF Research Database (Denmark)

    Kuhrmann, Marco; Richardson, Ita

    2015-01-01

    artifact models to direct process model improvement. We analyzed a process specification, the realized model, and the generated electronic process guide. We used ArSPI v0.9 as our process model and the Capability Maturity Model Integration (CMMI) as an external reference to provide a set of overall...

  2. MR-driven metal artifact reduction in PET/CT

    Science.gov (United States)

    Delso, G.; Wollenweber, S.; Lonn, A.; Wiesinger, F.; Veit-Haibach, P.

    2013-04-01

    Among the proposed system architectures capable of delivering positron emission tomography/magnetic resonance (PET/MR) datasets, tri-modality systems open an interesting field in which the synergies between these modalities can be exploited to address some of the problems encountered in standalone systems. In this paper we present a feasibility study of the correction of dental streak artifacts in computed tomography (CT)-based attenuation correction images using complementary MR data. The frequency and severity of metal artifacts in oncology patients was studied by inspecting the CT scans of 152 patients examined at our hospital. A prospective correction algorithm using CT and MR information to automatically locate and edit the region affected by metal artifacts was developed and tested retrospectively on data from 15 oncology patients referred for a PET/CT scan. In datasets without malignancies, the activity in Waldeyer's ring was used to measure the maximum uptake variation when the proposed correction was applied. The measured bias ranged from 10% to 30%. In datasets with malignancies on the slices affected by artifacts, the correction led to lesion uptake variations of 6.1% for a lesion 3 cm away from the implant, 1.5% for a lesion 7 cm away and <1% for a lesion 8 cm away.

  3. Dental artifacts in the head and neck region:

    DEFF Research Database (Denmark)

    Ladefoged, Claes N.; Hansen, Adam E.; Keller, Sune

    2015-01-01

    substituted with soft tissue information. Our inpainting algorithm delineates the outer contour of signal voids breaching the anatomical volume using the non-attenuation-corrected PET image and classifies the inner air regions based on an aligned template of likely dental artifact areas. The reconstructed PET...

  4. Communication in the Digital City and Artifact Lives

    Science.gov (United States)

    Kryssanov, Victor V.; Okabe, Masayuki; Kakusho, Koh; Minoh, Michihiko

    This paper proposes a theoretical basis for the design and analysis of distributed information systems. A quantitative criterion is defined to estimate the efficiency of computer-mediated communication, and to monitor artifact lives as well. The theoretical concepts are discussed in a context of an example related to car use and servicing.

  5. Classification of independent components of EEG into multiple artifact classes

    DEFF Research Database (Denmark)

    Frølich, Laura; Andersen, Tobias; Mørup, Morten

    2015-01-01

    In this study, we aim to automatically identify multiple artifact types in EEG. We used multinomial regression to classify independent components of EEG data, selecting from 65 spatial, spectral, and temporal features of independent components using forward selection. The classifier identified ne...

  6. Tracing the Paths of Moving Artifacts in Youth Media Production

    Science.gov (United States)

    Gibbons, Damiana

    2010-01-01

    Using a theoretical grounding in social semiotics, chronotopes, and social spaces with youth, I will discuss how identities are made possible and expressed in the interplay between the different parts of the youth video production process as youth artifacts as they move through time and space. The majority of my data is what I have come to term…

  7. Artifacts as Stories: Understanding Families, Digital Literacies, and Storied Lives

    Science.gov (United States)

    Lewis Ellison, Tisha

    2016-01-01

    This column focuses on the interactions during family and group conversation circles that not only helped participants talk about personal, emotional, and social issues in their digital stories but also helped them make sense of artifacts and the meanings that stories carry in shared spaces and practices. This work adds to the bourgeoning…

  8. 77 FR 40914 - Arts and Artifacts Indemnity Panel Advisory Committee

    Science.gov (United States)

    2012-07-11

    ... ARTS AND THE HUMANITIES Arts and Artifacts Indemnity Panel Advisory Committee AGENCY: Federal Council on the Arts and the Humanities, National Endowment for the Humanities, National Foundation on the Arts and the Humanities. ACTION: Notice of meeting. SUMMARY: Pursuant to section 10(a)(2) of the...

  9. 78 FR 4878 - Arts and Artifacts Indemnity Panel Advisory Committee

    Science.gov (United States)

    2013-01-23

    ... ARTS AND THE HUMANITIES Arts and Artifacts Indemnity Panel Advisory Committee AGENCY: Federal Council on the Arts and the Humanities; National Endowment for the Humanities. ACTION: Notice of meeting... hereby given that the Federal Council on the Arts and the Humanities will hold a meeting of the Arts and...

  10. 77 FR 64146 - Arts and Artifacts Indemnity Panel Advisory Committee

    Science.gov (United States)

    2012-10-18

    ... ARTS AND THE HUMANITIES Arts and Artifacts Indemnity Panel Advisory Committee AGENCY: Federal Council on the Arts and the Humanities, National Endowment for the Humanities. ACTION: Notice of meeting... hereby given that the Federal Council on the Arts and the Humanities will hold a meeting of the Arts and...

  11. Artifact suppression and analysis of brain activities with electroencephalography signals

    Science.gov (United States)

    Rashed-Al-Mahfuz, Md.; Islam, Md. Rabiul; Hirose, Keikichi; Molla, Md. Khademul Islam

    2013-01-01

    Brain-computer interface is a communication system that connects the brain with computer (or other devices) but is not dependent on the normal output of the brain (i.e., peripheral nerve and muscle). Electro-oculogram is a dominant artifact which has a significant negative influence on further analysis of real electroencephalography data. This paper presented a data adaptive technique for artifact suppression and brain wave extraction from electroencephalography signals to detect regional brain activities. Empirical mode decomposition based adaptive thresholding approach was employed here to suppress the electro-oculogram artifact. Fractional Gaussian noise was used to determine the threshold level derived from the analysis data without any training. The purified electroencephalography signal was composed of the brain waves also called rhythmic components which represent the brain activities. The rhythmic components were extracted from each electroencephalography channel using adaptive wiener filter with the original scale. The regional brain activities were mapped on the basis of the spatial distribution of rhythmic components, and the results showed that different regions of the brain are activated in response to different stimuli. This research analyzed the activities of a single rhythmic component, alpha with respect to different motor imaginations. The experimental results showed that the proposed method is very efficient in artifact suppression and identifying individual motor imagery based on the activities of alpha component. PMID:25206446

  12. Negligible Motion Artifacts in Scalp Electroencephalography (EEG) During Treadmill Walking.

    Science.gov (United States)

    Nathan, Kevin; Contreras-Vidal, Jose L

    2015-01-01

    Recent mobile brain/body imaging (MoBI) techniques based on active electrode scalp electroencephalogram (EEG) allow the acquisition and real-time analysis of brain dynamics during active unrestrained motor behavior involving whole body movements such as treadmill walking, over-ground walking and other locomotive and non-locomotive tasks. Unfortunately, MoBI protocols are prone to physiological and non-physiological artifacts, including motion artifacts that may contaminate the EEG recordings. A few attempts have been made to quantify these artifacts during locomotion tasks but with inconclusive results due in part to methodological pitfalls. In this paper, we investigate the potential contributions of motion artifacts in scalp EEG during treadmill walking at three different speeds (1.5, 3.0, and 4.5 km/h) using a wireless 64 channel active EEG system and a wireless inertial sensor attached to the subject's head. The experimental setup was designed according to good measurement practices using state-of-the-art commercially available instruments, and the measurements were analyzed using Fourier analysis and wavelet coherence approaches. Contrary to prior claims, the subjects' motion did not significantly affect their EEG during treadmill walking although precaution should be taken when gait speeds approach 4.5 km/h. Overall, these findings suggest how MoBI methods may be safely deployed in neural, cognitive, and rehabilitation engineering applications.

  13. Negligible motion artifacts in scalp electroencephalography (EEG during treadmill walking

    Directory of Open Access Journals (Sweden)

    Kevin eNathan

    2016-01-01

    Full Text Available Recent Mobile Brain/Body Imaging (MoBI techniques based on active electrode scalp electroencephalogram (EEG allow the acquisition and real-time analysis of brain dynamics during active unrestrained motor behavior involving whole body movements such as treadmill walking, over-ground walking and other locomotive and non-locomotive tasks. Unfortunately, MoBI protocols are prone to physiological and non-physiological artifacts, including motion artifacts that may contaminate the EEG recordings. A few attempts have been made to quantify these artifacts during locomotion tasks but with inconclusive results due in part to methodological pitfalls. In this paper, we investigate the potential contributions of motion artifacts in scalp EEG during treadmill walking at three different speeds (1.5, 3.0, and 4.5 km/h using a wireless 64 channel active EEG system and a wireless inertial sensor attached to the subject’s head. The experimental setup was designed according to good measurement practices using state-of-the-art commercially-available instruments, and the measurements were analyzed using Fourier analysis and wavelet coherence approaches. Contrary to prior claims, the subjects’ motion did not significantly affect their EEG during treadmill walking although precaution should be taken when gait speeds approach 4.5 km/h. Overall, these findings suggest how MoBI methods may be safely deployed in neural, cognitive, and rehabilitation engineering applications.

  14. Enhanced Automatic Wavelet Independent Component Analysis for Electroencephalographic Artifact Removal

    Directory of Open Access Journals (Sweden)

    Nadia Mammone

    2014-12-01

    Full Text Available Electroencephalography (EEG is a fundamental diagnostic instrument for many neurological disorders, and it is the main tool for the investigation of the cognitive or pathological activity of the brain through the bioelectromagnetic fields that it generates. The correct interpretation of the EEG is misleading, both for clinicians’ visual evaluation and for automated procedures, because of artifacts. As a consequence, artifact rejection in EEG is a key preprocessing step, and the quest for reliable automatic processors has been quickly growing in the last few years. Recently, a promising automatic methodology, known as automatic wavelet-independent component analysis (AWICA, has been proposed. In this paper, a more efficient and sensitive version, called enhanced-AWICA (EAWICA, is proposed, and an extensive performance comparison is carried out by a step of tuning the different parameters that are involved in artifact detection. EAWICA is shown to minimize information loss and to outperform AWICA in artifact removal, both on simulated and real experimental EEG recordings.

  15. Assessment of metal artifact reduction methods in pelvic CT

    Energy Technology Data Exchange (ETDEWEB)

    Abdoli, Mehrsima [Department of Radiation Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam 1066 CX (Netherlands); Mehranian, Abolfazl [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva CH-1211 (Switzerland); Ailianou, Angeliki; Becker, Minerva [Division of Radiology, Geneva University Hospital, Geneva CH-1211 (Switzerland); Zaidi, Habib, E-mail: habib.zaidi@hcuge.ch [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva CH-1211 (Switzerland); Geneva Neuroscience Center, Geneva University, Geneva CH-1205 (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, Groningen 9700 RB (Netherlands)

    2016-04-15

    Purpose: Metal artifact reduction (MAR) produces images with improved quality potentially leading to confident and reliable clinical diagnosis and therapy planning. In this work, the authors evaluate the performance of five MAR techniques for the assessment of computed tomography images of patients with hip prostheses. Methods: Five MAR algorithms were evaluated using simulation and clinical studies. The algorithms included one-dimensional linear interpolation (LI) of the corrupted projection bins in the sinogram, two-dimensional interpolation (2D), a normalized metal artifact reduction (NMAR) technique, a metal deletion technique, and a maximum a posteriori completion (MAPC) approach. The algorithms were applied to ten simulated datasets as well as 30 clinical studies of patients with metallic hip implants. Qualitative evaluations were performed by two blinded experienced radiologists who ranked overall artifact severity and pelvic organ recognition for each algorithm by assigning scores from zero to five (zero indicating totally obscured organs with no structures identifiable and five indicating recognition with high confidence). Results: Simulation studies revealed that 2D, NMAR, and MAPC techniques performed almost equally well in all regions. LI falls behind the other approaches in terms of reducing dark streaking artifacts as well as preserving unaffected regions (p < 0.05). Visual assessment of clinical datasets revealed the superiority of NMAR and MAPC in the evaluated pelvic organs and in terms of overall image quality. Conclusions: Overall, all methods, except LI, performed equally well in artifact-free regions. Considering both clinical and simulation studies, 2D, NMAR, and MAPC seem to outperform the other techniques.

  16. Hybrid wavelet and EMD/ICA approach for artifact suppression in pervasive EEG.

    Science.gov (United States)

    Bono, Valentina; Das, Saptarshi; Jamal, Wasifa; Maharatna, Koushik

    2016-07-15

    Electroencephalogram (EEG) signals are often corrupted with unintended artifacts which need to be removed for extracting meaningful clinical information from them. Typically a priori knowledge of the nature of the artifacts is needed for such purpose. Artifact contamination of EEG is even more prominent for pervasive EEG systems where the subjects are free to move and thereby introducing a wide variety of motion-related artifacts. This makes hard to get a priori knowledge about their characteristics rendering conventional artifact removal techniques often ineffective. In this paper, we explore the performance of two hybrid artifact removal algorithms: Wavelet Packet Transform followed by Independent Component Analysis (WPTICA) and Wavelet Packet Transform followed by Empirical Mode Decomposition (WPTEMD) in pervasive EEG recording scenario, assuming existence of no a priori knowledge about the artifacts and compare their performance with two existing artifact removal algorithms. Artifact cleaning performance has been measured using Root Mean Square Error (RMSE) and Artifact to Signal Ratio (ASR)-an index similar to traditional Signal to Noise Ratio (SNR), and also by observing normalized power distribution topography over the scalp. Comparison has been made first using semi-simulated signals and then with real experimentally acquired EEG data with commercially available 19-channel pervasive EEG system Enobio corrupted by eight types of artifact. Our explorations show that WPTEMD consistently gives best artifact cleaning performance not only in semi-simulated scenario but also in the case of real EEG data containing artifacts. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Total Variation-Based Reduction of Streak Artifacts, Ring Artifacts and Noise in 3D Reconstruction from Optical Projection Tomography

    Czech Academy of Sciences Publication Activity Database

    Michálek, Jan

    2015-01-01

    Roč. 21, č. 6 (2015), s. 1602-1615 ISSN 1431-9276 R&D Projects: GA MŠk(CZ) LH13028; GA ČR(CZ) GA13-12412S Institutional support: RVO:67985823 Keywords : optical projection tomography * microscopy * artifacts * total variation * data mismatch Subject RIV: EA - Cell Biology Impact factor: 1.730, year: 2015

  18. Green space as classroom

    DEFF Research Database (Denmark)

    Bentsen, Peter; Schipperijn, Jasper; Jensen, Frank Søndergaard

    2013-01-01

    More and more Danish teachers have started introducing curriculum-based outdoor learning as a weekly or biweekly ‘outdoor school’ day for school children. This move towards schooling in non-classroom spaces presents a challenge for green space managers. Basic managerial knowledge related to what......, who, when and where has thus far only been supported by anecdotal evidence, but seems fundamental to the decision-making of a range of green space providers. The present study aims to describe, characterise and discuss outdoor teachers’ use, preferences and ecostrategies in relation to green space....... A nationwide survey was conducted among Danish teachers practising outdoor teaching (107 respondents), and it showed that a majority used and preferred forest areas. The outdoor teachers used mainly school grounds and local green space for their outdoor teaching with a majority using the same place or mostly...

  19. Generic Language Use Reveals Domain Differences in Young Children's Expectations about Animal and Artifact Categories

    Science.gov (United States)

    Brandone, Amanda C.; Gelman, Susan A.

    2013-01-01

    The goal of the present study was to explore domain differences in young children's expectations about the structure of animal and artifact categories. We examined 5-year-olds' and adults' use of category-referring generic noun phrases (e.g., "Birds fly") about novel animals and artifacts. The same stimuli served as both animals and artifacts;…

  20. Digital Library Archaeology: A Conceptual Framework for Understanding Library Use through Artifact-Based Evaluation

    Science.gov (United States)

    Nicholson, Scott

    2005-01-01

    Archaeologists have used material artifacts found in a physical space to gain an understanding about the people who occupied that space. Likewise, as users wander through a digital library, they leave behind data-based artifacts of their activity in the virtual space. Digital library archaeologists can gather these artifacts and employ inductive…

  1. Development of tools and techniques for monitoring underwater artifacts

    Science.gov (United States)

    Lazar, Iulian; Ghilezan, Alin; Hnatiuc, Mihaela

    2016-12-01

    The different assessments provide information on the best methods to approach an artifact. The presence and extent of potential threats to archaeology must also be determined. In this paper we present an underwater robot, built in the laboratory, able to identify the artifact and to get it to the surface. It is an underwater remotely operated vehicle (ROV) which can be controlled remotely from the shore, a boat or a control station and communication is possible through an Ethernet cable with a maximum length of 100 m. The robot is equipped with an IP camera which sends real time images that can be accessed anywhere from within the network. The camera also has a microSD card to store the video. The methods developed for data communication between the robot and the user is present. A communication protocol between the client and server is developed to control the ROV.

  2. Coevolution of variability models and related software artifacts

    DEFF Research Database (Denmark)

    Passos, Leonardo; Teixeira, Leopoldo; Dinztner, Nicolas

    2015-01-01

    models coevolve with other artifact types, we study a large and complex real-world variant-rich software system: the Linux kernel. Specifically, we extract variability-coevolution patterns capturing changes in the variability model of the Linux kernel with subsequent changes in Makefiles and C source......Variant-rich software systems offer a large degree of customization, allowing users to configure the target system according to their preferences and needs. Facing high degrees of variability, these systems often employ variability models to explicitly capture user-configurable features (e...... to the evolution of different kinds of software artifacts, it is not surprising that industry reports existing tools and solutions ineffective, as they do not handle the complexity found in practice. Attempting to mitigate this overall lack of knowledge and to support tool builders with insights on how variability...

  3. Automatic Crash Recovery Artifacts From Internet Explorer 8 And 9

    Directory of Open Access Journals (Sweden)

    John Moran

    2012-09-01

    Full Text Available A good portion of today’s investigations include, at least in part, an examination of the user’s web history.Although it has lost ground over the past several years, Microsoft’s Internet Explorer still accounts for a large portion of the web browser market share.Most users are now aware that Internet Explorer will save browsing history, user names, passwords and form history.Consequently some users seek to eliminate these artifacts, leaving less for examiners to discover during investigations.However, most users, and probably a good portion of examiners are unaware Automatic Crash Recovery, can leave a gold mine of recent browsing history in spite of the users attempts to delete historical artifacts.

  4. Interpolation strategies for reducing IFOV artifacts in microgrid polarimeter imagery.

    Science.gov (United States)

    Ratliff, Bradley M; LaCasse, Charles F; Tyo, J Scott

    2009-05-25

    Microgrid polarimeters are composed of an array of micro-polarizing elements overlaid upon an FPA sensor. In the past decade systems have been designed and built in all regions of the optical spectrum. These systems have rugged, compact designs and the ability to obtain a complete set of polarimetric measurements during a single image capture. However, these systems acquire the polarization measurements through spatial modulation and each measurement has a varying instantaneous field-of-view (IFOV). When these measurements are combined to estimate the polarization images, strong edge artifacts are present that severely degrade the estimated polarization imagery. These artifacts can be reduced when interpolation strategies are first applied to the intensity data prior to Stokes vector estimation. Here we formally study IFOV error and the performance of several bilinear interpolation strategies used for reducing it.

  5. Teacher Self-Efficacy: A Classroom-Organization Conceptualization.

    Science.gov (United States)

    Friedman, Isaac A.; Kass, Efrat

    2002-01-01

    Surveyed and interviewed Israeli elementary and secondary teachers to provide support for an expanded conceptual model of teacher self-efficacy, the Classroom and School Context model. This re-conceptualization considers teacher tasks and relationships in both the classroom and school organization context. Results found a good fit between the…

  6. Persistent Classroom Management Training Needs of Experienced Teachers

    Science.gov (United States)

    Stough, Laura M.; Montague, Marcia L.; Landmark, Leena Jo; Williams-Diehm, Kendra

    2015-01-01

    Experienced special education teachers (n = 62) were surveyed on their professional preparation to become effective classroom managers. Despite having received extensive preservice training, over 83% of the sample reported being underprepared in classroom management and behavioral interventions. No statistically significant difference was found…

  7. An Investigation of University Students' Classroom Seating Choices

    Science.gov (United States)

    Xi, Li; Yuan, Zhang; YunQui, Bai; Chiang, Feng-Kuang

    2017-01-01

    The classroom is crucial for students, and seating position within the classroom can affect students' performance. This study conducted a survey to investigate the relationship between seating zones and academic performance among 174 university students in Beijing. The results revealed differences in student performance in terms of seating…

  8. Geography Teachers' Attitudes and Beliefs Regarding Classroom Management

    Science.gov (United States)

    Dikmenli, Yurdal; Çifçi, Taner

    2016-01-01

    This study scrutinizes geography teachers' attitude and belief levels regarding classroom management. As a matter of fact, classroom management is one of the prominent areas emphasized by all educators. Descriptive correlational survey model was used in the study. Study group includes 58 geography teachers working in Sivas province during the…

  9. Essential Layers, Artifacts, and Dependencies of Enterprise Architecture

    OpenAIRE

    Winter, Robert; Fischer, Ronny

    2007-01-01

    After a period where implementation speed was more important than integration, consistency and reduction of complexity, architectural considerations have become a key issue of information management in recent years again. Enterprise architecture is widely accepted as an essential mechanism for ensuring agility and consistency, compliance and efficiency. Although standards like TOGAF and FEAF have developed, however, there is no common agreement on which architecture layers, which artifact typ...

  10. Carbon fiber intramedullary nails reduce artifact in postoperative advanced imaging

    Energy Technology Data Exchange (ETDEWEB)

    Zimel, Melissa N. [Memorial Sloan Kettering Cancer Center, Orthopaedic Surgery Service, Department of Surgery, New York, NY (United States); Hwang, Sinchun [Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, NY (United States); Riedel, Elyn R. [Memorial Sloan Kettering Cancer Center, Department of Epidemiology and Biostatistics, New York, NY (United States); Healey, John H. [Memorial Sloan Kettering Cancer Center, Orthopaedic Surgery Service, Department of Surgery, New York, NY (United States); Weill Medical College of Cornell University, Department of Orthopaedic Surgery, New York, NY (United States)

    2015-09-15

    This study assessed whether radiolucent carbon fiber reinforced-polyetheretherketone (CFR-PEEK) intramedullary nails decreased hardware artifact on magnetic resonance imaging (MRI) and computed tomography (CT) in vitro and in an oncologic patient population. In vitro and clinical evaluations were done. A qualitative assessment of metal artifact was performed using CFR-PEEK and titanium nail MRI phantoms. Eight patients with a femoral or tibial prophylactic CFR-PEEK nail were retrospectively identified. All patients had postoperative surveillance imaging by MRI, CT, and were followed for a median 20 months (range, 12-28 months). CFR-PEEK images were compared to images from a comparative group of patients with titanium femoral intramedullary nails who had a postoperative MRI or CT. A musculoskeletal-trained radiologist graded visualization of the cortex, corticomedullary junction, and bone-muscle interface, on T1-weighted (T1W), STIR, and contrast-enhanced T1-weighted fat-saturated (T1W FS) sequences of both groups with a five-point scale, performing independent reviews 4 months apart. Statistical analysis used the Wilcoxon rank-sum test and a weighted kappa. Substantially less MRI signal loss occurred in the CFR-PEEK phantom than in the titanium phantom simulation, particularly as the angle increased with respect to direction of the static magnetic field. CFR-PEEK nails had less MRI artifact than titanium nails on scored T1W, STIR, and contrast-enhanced T1W FS MRI sequences (p ≤ 0.03). The mean weighted kappa was 0.64, showing excellent intraobserver reliability between readings. CFR-PEEK intramedullary nail fixation is a superior alternative to minimize implant artifact on MRI or CT imaging for patients requiring long bone fixation. (orig.)

  11. The Multifaceted Use of a Written Artifact in Student Supervision

    Directory of Open Access Journals (Sweden)

    Gunilla Jansson

    2011-01-01

    Full Text Available This article explores the use of a written artifact, an assessment form encompassing a checklist with health care terms, in supervised nurse student-patient interactions during assessment interviews in a Swedish hospital ward. The students were doing their clinical practice and were in their first year of a three-year nursing degree. Even though the students are not in charge of the situation, they are expected to perform a professional task for which they lack adequate skills. As demonstrated, the use of the assessment form provided a useful way for the participants to manage specific tasks in an apprenticeship context, such as regulating affect display, demonstrating uptake of the patient's concerns and staging the interview as an exercise. For this article, three excerpts have been selected from history-taking sequences, when the patient's previous illness history is created. The analysis illustrates the affordances provided by the assessment form to handle perspective shifts, when the patient departs from a general pattern of unelaborated answers and offers a window into his/her concerns. Importantly, however, the students' feedback talk with the nurse preceptor offers evidence that the artifact also constrains their forms of action in the practice of gathering assessment data. The article argues for ward-level practices that socialize students into reflective ways of using the artifact.

  12. Reduction of artifacts in computer simulation of breast Cooper's ligaments

    Science.gov (United States)

    Pokrajac, David D.; Kuperavage, Adam; Maidment, Andrew D. A.; Bakic, Predrag R.

    2016-03-01

    Anthropomorphic software breast phantoms have been introduced as a tool for quantitative validation of breast imaging systems. Efficacy of the validation results depends on the realism of phantom images. The recursive partitioning algorithm based upon the octree simulation has been demonstrated as versatile and capable of efficiently generating large number of phantoms to support virtual clinical trials of breast imaging. Previously, we have observed specific artifacts, (here labeled "dents") on the boundaries of simulated Cooper's ligaments. In this work, we have demonstrated that these "dents" result from the approximate determination of the closest simulated ligament to an examined subvolume (i.e., octree node) of the phantom. We propose a modification of the algorithm that determines the closest ligament by considering a pre-specified number of neighboring ligaments selected based upon the functions that govern the shape of ligaments simulated in the subvolume. We have qualitatively and quantitatively demonstrated that the modified algorithm can lead to elimination or reduction of dent artifacts in software phantoms. In a proof-of concept example, we simulated a 450 ml phantom with 333 compartments at 100 micrometer resolution. After the proposed modification, we corrected 148,105 dents, with an average size of 5.27 voxels (5.27nl). We have also qualitatively analyzed the corresponding improvement in the appearance of simulated mammographic images. The proposed algorithm leads to reduction of linear and star-like artifacts in simulated phantom projections, which can be attributed to dents. Analysis of a larger number of phantoms is ongoing.

  13. A unified canonical correlation analysis-based framework for removing gradient artifact in concurrent EEG/fMRI recording and motion artifact in walking recording from EEG signal.

    Science.gov (United States)

    Li, Junhua; Chen, Yu; Taya, Fumihiko; Lim, Julian; Wong, Kianfoong; Sun, Yu; Bezerianos, Anastasios

    2017-09-01

    Artifacts cause distortion and fuzziness in electroencephalographic (EEG) signal and hamper EEG analysis, so it is necessary to remove them prior to the analysis. Particularly, artifact removal becomes a critical issue in experimental protocols with significant inherent recording noise, such as mobile EEG recordings and concurrent EEG-fMRI acquisitions. In this paper, we proposed a unified framework based on canonical correlation analysis for artifact removal. Raw signals were reorganized to construct a pair of matrices, based on which sources were sought through maximizing autocorrelation. Those sources related to artifacts were then removed by setting them as zeros, and the remaining sources were used to reconstruct artifact-free EEG. Both simulated and real recorded data were utilized to assess the proposed framework. Qualitative and quantitative results showed that the proposed framework was effective to remove artifacts from EEG signal. Specifically, the proposed method outperformed independent component analysis method for mitigating motion-related artifacts and had advantages for removing gradient artifact compared to the classical method (average artifacts subtraction) and the state-of-the-art method (optimal basis set) in terms of the combination of performance and computational complexity.

  14. Teacher Logs: A Tool for Gaining a Comprehensive Understanding of Classroom Practices

    Science.gov (United States)

    Glennie, Elizabeth J.; Charles, Karen J.; Rice, Olivia N.

    2017-01-01

    Examining repeated classroom encounters over time provides a comprehensive picture of activities. Studies of instructional practices in classrooms have traditionally relied on two methods: classroom observations, which are expensive, and surveys, which are limited in scope and accuracy. Teacher logs provide a "real-time" method for…

  15. Tips from the Classroom.

    Science.gov (United States)

    Hess, Natalie; And Others

    1995-01-01

    Six classroom tips for language teachers focus on creating a congenial classroom environment, integrating listening and reading skills, teaching idioms from tabloid newspapers, cooperative learning in honors courses, grammar games, and teaching culture through personalized automobile license plate messages. (MDM)

  16. Applying a Goal Programming Model to Support the Selection of Artifacts in a Testing Process

    Directory of Open Access Journals (Sweden)

    Andreia Rodrigues da Silva

    2012-01-01

    Full Text Available This paper proposes the definition of a goal programming model for the selection of artifacts to be developed during a testing process, so that the set of selected artifacts is more viable to the reality of micro and small enterprises. This model was based on the IEEE Standard 829, which establishes a set of artifacts that must be generated throughout the test activities. Several factors can influence the definition of this set of artifacts. Therefore, in order to consider such factors, we developed a multicriteria model that helps in determining the priority of artifacts according to the reality of micro and small enterprises.

  17. Student evaluation of the flipped classroom instruction method: is it aligned with Problem-Based Learning?

    DEFF Research Database (Denmark)

    Triantafyllou, Evangelia; Timcenko, Olga; Kofoed, Lise

    2017-01-01

    The flipped classroom approach is an instructional method that has gained momentum in the last years. In a flipped classroom the traditional lecture and homework sessions are inverted. We believe that the flipped classroom, which employs computer-based individual instruction outside the classroom...... and devotes classroom time to group activities with the teacher as facilitator is well justified by the core principles of Problem-Based Learning (PBL) and therefore we applied for two consecutive years the flipped classroom approach to an undergraduate statistics course during a whole semester. This paper...... presents data from the second year, where we conducted a survey study among students participating in the flipped statistics course. This study consisted of two surveys designed to gather student perceptions on the out-of-classroom preparation material (videos and quizzes) and the flipped classroom...

  18. Classroom Management. TESOL Classroom Practice Series

    Science.gov (United States)

    Farrell, Thomas S. C., Ed.

    2008-01-01

    This series captures the dynamics of the contemporary ESOL classroom. It showcases state-of-the-art curricula, materials, tasks, and activities reflecting emerging trends in language education and seeks to build localized language teaching and learning theories based on teachers' and students' unique experiences in and beyond the classroom. Each…

  19. Critical Classroom Discourse Analysis.

    Science.gov (United States)

    Kumaravadivelu, B.

    1999-01-01

    Conceptualizes a framework for conducting critical classroom-discourse analysis. Critiques the scope and method of current models of classroom-interaction analysis and classroom-discourse analysis and advocates using poststructuralist and postcolonialist understandings of discourse to develop a critical framework for understanding what actually…

  20. Encouraging Classroom Discussion

    Directory of Open Access Journals (Sweden)

    Robert Joseph McKee

    2014-10-01

    Full Text Available Classroom discussion has the potential to enhance the learning environment and encourages students to become active participants in the educational process. Student participation in classroom discussion has been shown to significantly improve the student learning experience. Research suggests that classroom discussion is an effective method for encouraging student classroom participation and for motivating student learning beyond the classroom. Participation in classroom discussion encourages students to become active collaborators in the learning process, while at the same time providing instructors with a practical method of assessing student learning. Classroom discussion is an effective tool for developing higher-level cognitive skills like critical thinking. Despite the potential discussion holds for student learning, many in academia lament the lack of participation in the classroom. The lack of student participation in classroom discussion is not a recent problem; it is one that has frustrated instructors for decades. Instructors report that some of the more current methods for encouraging classroom discussion can be exasperating and at times non-productive. This two-year study of 510 college and university students provides insight into the reasons why some students do not participate in classroom discussion. This study, which also elicited input from sixteen college and university professors and two high school teachers, offers some suggestions for creating and encouraging an environment conducive to student participation in the classroom.

  1. A novel method for removal of deep brain stimulation artifact from electroencephalography.

    Science.gov (United States)

    Sun, Yinming; Farzan, Faranak; Garcia Dominguez, Luis; Barr, Mera S; Giacobbe, Peter; Lozano, Andres M; Wong, Willy; Daskalakis, Zafiris J

    2014-11-30

    Deep brain stimulation (DBS) has treatment efficacy in neurological and psychiatric disorders such as Parkinson's disease and major depression. Electroencephalography (EEG) is a versatile neurophysiological tool that can be used to better understand DBS treatment mechanisms. DBS causes artifacts in EEG recordings that preclude meaningful neurophysiological activity from being quantified during stimulation. In this study, we modeled the DBS stimulation artifact and illustrated a technique for removing the artifact using matched filters. The approach was validated using a synthetically generated DBS artifact superimposed on EEG data. Mean squared error (MSE) between the recovered signal and the artifact-free signal was used to quantify the effectiveness of the approach. The DBS artifact was characterized by a series of narrow band components at the harmonic frequencies of DBS stimulation. The filtering approach successfully removed the DBS artifact with MSE value being less than 2% of base signal power for the typical stimulation and recording setups. General guidelines on how to setup DBS EEG studies and configure the subsequent artifact removal process are described. To avoid stimulus artifacts, a number of EEG studies with DBS subjects have resorted to turning the stimulator off during recording, while other studies have used low pass filters to remove artifacts and look at frequencies well below 50 Hz. This study establishes a method through which DBS artifact in EEG recordings can be reliably eliminated, thereby preserving a meaningful neurophysiological signal through which to better understand DBS treatment mechanisms. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Removal of ring artifacts in microtomography by characterization of scintillator variations.

    Science.gov (United States)

    Vågberg, William; Larsson, Jakob C; Hertz, Hans M

    2017-09-18

    Ring artifacts reduce image quality in tomography, and arise from faulty detector calibration. In microtomography, we have identified that ring artifacts can arise due to high-spatial frequency variations in the scintillator thickness. Such variations are normally removed by a flat-field correction. However, as the spectrum changes, e.g. due to beam hardening, the detector response varies non-uniformly introducing ring artifacts that persist after flat-field correction. In this paper, we present a method to correct for ring artifacts from variations in scintillator thickness by using a simple method to characterize the local scintillator response. The method addresses the actual physical cause of the ring artifacts, in contrary to many other ring artifact removal methods which rely only on image post-processing. By applying the technique to an experimental phantom tomography, we show that ring artifacts are strongly reduced compared to only making a flat-field correction.

  3. A peer review process for classroom teaching.

    Science.gov (United States)

    Wellein, Marlea G; Ragucci, Kelly R; Lapointe, Marc

    2009-08-28

    Describe the planning, implementation, and faculty perceptions of a classroom peer-review process, including an evaluation tool. A process for peer evaluation of classroom teaching and its evaluation tool were developed and implemented by a volunteer faculty committee within our department. At the end of the year, all faculty members were asked to complete an online anonymous survey to evaluate the experience. The majority of faculty members either agreed or strongly agreed that the overall evaluation process was beneficial for both evaluators and for those being evaluated. Some areas of improvement related to the process and its evaluation tool also were identified. The process of developing and implementing a peer-evaluation process for classroom teaching was found to be beneficial for faculty members, and the survey results affirmed the need and continuation of such a process.

  4. Isolating gait-related movement artifacts in electroencephalography during human walking

    Science.gov (United States)

    Kline, Julia E.; Huang, Helen J.; Snyder, Kristine L.; Ferris, Daniel P.

    2015-08-01

    Objective. High-density electroencephelography (EEG) can provide an insight into human brain function during real-world activities with walking. Some recent studies have used EEG to characterize brain activity during walking, but the relative contributions of movement artifact and electrocortical activity have been difficult to quantify. We aimed to characterize movement artifact recorded by EEG electrodes at a range of walking speeds and to test the efficacy of artifact removal methods. We also quantified the similarity between movement artifact recorded by EEG electrodes and a head-mounted accelerometer. Approach. We used a novel experimental method to isolate and record movement artifact with EEG electrodes during walking. We blocked electrophysiological signals using a nonconductive layer (silicone swim cap) and simulated an electrically conductive scalp on top of the swim cap using a wig coated with conductive gel. We recorded motion artifact EEG data from nine young human subjects walking on a treadmill at speeds from 0.4 to 1.6 m s-1. We then tested artifact removal methods including moving average and wavelet-based techniques. Main results. Movement artifact recorded with EEG electrodes varied considerably, across speed, subject, and electrode location. The movement artifact measured with EEG electrodes did not correlate well with head acceleration. All of the tested artifact removal methods attenuated low-frequency noise but did not completely remove movement artifact. The spectral power fluctuations in the movement artifact data resembled data from some previously published studies of EEG during walking. Significance. Our results suggest that EEG data recorded during walking likely contains substantial movement artifact that: cannot be explained by head accelerations; varies across speed, subject, and channel; and cannot be removed using traditional signal processing methods. Future studies should focus on more sophisticated methods for removal of EEG

  5. Isolating gait-related movement artifacts in electroencephalography during human walking.

    Science.gov (United States)

    Kline, Julia E; Huang, Helen J; Snyder, Kristine L; Ferris, Daniel P

    2015-08-01

    High-density electroencephelography (EEG) can provide an insight into human brain function during real-world activities with walking. Some recent studies have used EEG to characterize brain activity during walking, but the relative contributions of movement artifact and electrocortical activity have been difficult to quantify. We aimed to characterize movement artifact recorded by EEG electrodes at a range of walking speeds and to test the efficacy of artifact removal methods. We also quantified the similarity between movement artifact recorded by EEG electrodes and a head-mounted accelerometer. We used a novel experimental method to isolate and record movement artifact with EEG electrodes during walking. We blocked electrophysiological signals using a nonconductive layer (silicone swim cap) and simulated an electrically conductive scalp on top of the swim cap using a wig coated with conductive gel. We recorded motion artifact EEG data from nine young human subjects walking on a treadmill at speeds from 0.4 to 1.6 m s(-1). We then tested artifact removal methods including moving average and wavelet-based techniques. Movement artifact recorded with EEG electrodes varied considerably, across speed, subject, and electrode location. The movement artifact measured with EEG electrodes did not correlate well with head acceleration. All of the tested artifact removal methods attenuated low-frequency noise but did not completely remove movement artifact. The spectral power fluctuations in the movement artifact data resembled data from some previously published studies of EEG during walking. Our results suggest that EEG data recorded during walking likely contains substantial movement artifact that: cannot be explained by head accelerations; varies across speed, subject, and channel; and cannot be removed using traditional signal processing methods. Future studies should focus on more sophisticated methods for removal of EEG movement artifact to advance the field.

  6. The Inverted Agricultural Economics Classroom: A new way to teach? A new way to learn?

    OpenAIRE

    Gardner, Justin G.

    2012-01-01

    The purpose of this paper is to introduce an emerging teaching method, the inverted classroom, to agricultural economists. The reader will learn the pros and cons of this method and the tools needed to create an inverted course. Data on student perceptions of the inverted classroom is presented, as well as an estimate of the relationship between student perceptions and student performance in an inverted classroom. The surveyed students responded positively to the inverted classroom concept; h...

  7. Multimodal integration of anatomy and physiology classes: How instructors utilize multimodal teaching in their classrooms

    Science.gov (United States)

    McGraw, Gerald M., Jr.

    Multimodality is the theory of communication as it applies to social and educational semiotics (making meaning through the use of multiple signs and symbols). The term multimodality describes a communication methodology that includes multiple textual, aural, and visual applications (modes) that are woven together to create what is referred to as an artifact. Multimodal teaching methodology attempts to create a deeper meaning to course content by activating the higher cognitive areas of the student's brain, creating a more sustained retention of the information (Murray, 2009). The introduction of multimodality educational methodologies as a means to more optimally engage students has been documented within educational literature. However, studies analyzing the distribution and penetration into basic sciences, more specifically anatomy and physiology, have not been forthcoming. This study used a quantitative survey design to determine the degree to which instructors integrated multimodality teaching practices into their course curricula. The instrument used for the study was designed by the researcher based on evidence found in the literature and sent to members of three associations/societies for anatomy and physiology instructors: the Human Anatomy and Physiology Society; the iTeach Anatomy & Physiology Collaborate; and the American Physiology Society. Respondents totaled 182 instructor members of two- and four-year, private and public higher learning colleges collected from the three organizations collectively with over 13,500 members in over 925 higher learning institutions nationwide. The study concluded that the expansion of multimodal methodologies into anatomy and physiology classrooms is at the beginning of the process and that there is ample opportunity for expansion. Instructors continue to use lecture as their primary means of interaction with students. Email is still the major form of out-of-class communication for full-time instructors. Instructors with

  8. A case study of intersections between a physics classroom and industry

    Science.gov (United States)

    Jadonath, Capildeo

    The purpose of this study was to describe a journey for one teacher and his students. This journey involved bridging the gap between his classroom and high-tech workplaces, while engaging students in an integrated physics curriculum called Advanced Technology Education (ATE). This integrated curriculum is grounded in physics and interwoven with both Principles of Technology (PT) and Integrated Systems Technology (IST). ATE integrates the learning of technical skills, people skills, and academics through real world applications in manufacturing, production and engineering technology. The study was qualitative and employed a specific genre of research, the case study and it included both qualitative and quantitative data collection. This case study design originated from anthropology and has the following four characteristics: particularistic, descriptive, heuristic, and inductive. Data were collected over a 2-year period (August 1996-June 1998), by the researcher who was simultaneously the participants' instructor. This allowed me to be the prime instrument for the study and also become an "insider". The techniques of data collection were guided primarily by the research questions. Multiple sources of evidence included: documents, interviews, archival records, direct observations, participant observations, physical artifacts, and surveys (students, parents, and faculty).

  9. Curbing Digital Distractions in the Classroom

    Science.gov (United States)

    Seemiller, Corey

    2017-01-01

    Whether banking, communicating, watching television, or shopping, people can now do nearly anything on their personal digital devices. This digital access even extends to the college classroom where students use their personal devices for a multitude of non-class related purposes. Findings from a survey of 193 college undergraduates found that…

  10. ORIGINAL ARTICLE An Assessment of Mathematics Classroom ...

    African Journals Online (AJOL)

    Bdu

    constructivism. Data about the learning environment in mathematics classroom was collected using the Constructivist Learning Environment Survey (CLES). The CLES consists of five dimensions (scales): personal relevance, mathematical uncertainty, shared control, critical voice, and student negotiation, each scale having ...

  11. Iterative metal artifact reduction: Evaluation and optimization of technique

    Energy Technology Data Exchange (ETDEWEB)

    Subhas, Naveen; Gupta, Amit; Polster, Joshua M. [Imaging Institute, Cleveland Clinic, Cleveland, OH (United States); Primak, Andrew N. [Siemens Medical Solutions USA Inc., Malvern, PA (United States); Obuchowski, Nancy A. [Quantitative Health Sciences, Cleveland Clinic, Cleveland, OH (United States); Krauss, Andreas [Siemens Healthcare, Forchheim (Germany); Iannotti, Joseph P. [Orthopaedic and Rheumatologic Institute, Cleveland Clinic, Cleveland, OH (United States)

    2014-12-15

    Iterative metal artifact reduction (IMAR) is a sinogram inpainting technique that incorporates high-frequency data from standard weighted filtered back projection (WFBP) reconstructions to reduce metal artifact on computed tomography (CT). This study was designed to compare the image quality of IMAR and WFBP in total shoulder arthroplasties (TSA); determine the optimal amount of WFBP high-frequency data needed for IMAR; and compare image quality of the standard 3D technique with that of a faster 2D technique. Eight patients with nine TSA underwent CT with standardized parameters: 140 kVp, 300 mAs, 0.6 mm collimation and slice thickness, and B30 kernel. WFBP, three 3D IMAR algorithms with different amounts of WFBP high-frequency data (IMARlo, lowest; IMARmod, moderate; IMARhi, highest), and one 2D IMAR algorithm were reconstructed. Differences in attenuation near hardware and away from hardware were measured and compared using repeated measures ANOVA. Five readers independently graded image quality; scores were compared using Friedman's test. Attenuation differences were smaller with all 3D IMAR techniques than with WFBP (p < 0.0063). With increasing high-frequency data, the attenuation difference increased slightly (differences not statistically significant). All readers ranked IMARmod and IMARhi more favorably than WFBP (p < 0.05), with IMARmod ranked highest for most structures. The attenuation difference was slightly higher with 2D than with 3D IMAR, with no significant reader preference for 3D over 2D. IMAR significantly decreases metal artifact compared to WFBP both objectively and subjectively in TSA. The incorporation of a moderate amount of WFBP high-frequency data and use of a 2D reconstruction technique optimize image quality and allow for relatively short reconstruction times. (orig.)

  12. Flipping the Continuing Medical Education Classroom: Validating a Measure of Attendees' Perceptions.

    Science.gov (United States)

    Stephenson, Christopher R; Wang, Amy T; Szostek, Jason H; Bonnes, Sara L; Ratelle, John T; Mahapatra, Saswati; Mandrekar, Jayawant N; Beckman, Thomas J; Wittich, Christopher M

    2016-01-01

    New teaching approaches for CME are needed. In flipped classrooms, coursework is completed beforehand and applied during class time. Studies of flipped classrooms and their potential benefits in CME have not been published. We sought to develop and validate an instrument measuring flipped classroom perceptions, identify whether participation changed perceptions, and determine which flipped classroom components were perceived as most effective. In this cross-sectional validation study, 167 participants in the Mayo Clinic's 2015 Internal Medicine Board Review course received surveys. Online modules were developed to deliver content before flipped classroom courses on acid-base disorders and electrolyte disorders. A flipped classroom perception instrument (FCPI) was developed and validated. The FCPI, with eight items structured on 5-point Likert scales, was given to participants before and after their flipped classroom experiences. Of the 167 participants, 111 returned surveys. Flipped classroom perceptions improved, with mean (SD) FCPI scores increasing from 3.74 (0.75) to 3.94 (0.76) (P flipped classrooms increased from 38% before the course to 53% after (P = .002). Positive changes in FCPI scores were unrelated to module completion. Most participants thought knowledge was enhanced by in-class sessions and online modules equally. The FCPI, the first validated measure of participants' perceptions of a CME flipped classroom, has strong validity evidence. Participants' perceptions of and preference for the flipped classroom improved after experiencing the flipped CME classroom. These findings support the need to further explore flipped classroom models in CME.

  13. Improving the speech intelligibility in classrooms

    Science.gov (United States)

    Lam, Choi Ling Coriolanus

    One of the major acoustical concerns in classrooms is the establishment of effective verbal communication between teachers and students. Non-optimal acoustical conditions, resulting in reduced verbal communication, can cause two main problems. First, they can lead to reduce learning efficiency. Second, they can also cause fatigue, stress, vocal strain and health problems, such as headaches and sore throats, among teachers who are forced to compensate for poor acoustical conditions by raising their voices. Besides, inadequate acoustical conditions can induce the usage of public address system. Improper usage of such amplifiers or loudspeakers can lead to impairment of students' hearing systems. The social costs of poor classroom acoustics will be large to impair the learning of children. This invisible problem has far reaching implications for learning, but is easily solved. Many researches have been carried out that they have accurately and concisely summarized the research findings on classrooms acoustics. Though, there is still a number of challenging questions remaining unanswered. Most objective indices for speech intelligibility are essentially based on studies of western languages. Even several studies of tonal languages as Mandarin have been conducted, there is much less on Cantonese. In this research, measurements have been done in unoccupied rooms to investigate the acoustical parameters and characteristics of the classrooms. The speech intelligibility tests, which based on English, Mandarin and Cantonese, and the survey were carried out on students aged from 5 years old to 22 years old. It aims to investigate the differences in intelligibility between English, Mandarin and Cantonese of the classrooms in Hong Kong. The significance on speech transmission index (STI) related to Phonetically Balanced (PB) word scores will further be developed. Together with developed empirical relationship between the speech intelligibility in classrooms with the variations

  14. Development of an artifact-free aneurysm clip

    Directory of Open Access Journals (Sweden)

    Brack Alexander

    2016-09-01

    Full Text Available For the treatment of intracranial aneurysms with aneurysm clips, usually a follow-up inspection in MRI is required. To avoid any artifacts, which can make a proper diagnosis difficult, a new approach for the manufacturing of an aneurysm clip entirely made from fiber-reinforced plastics has been developed. In this paper the concept for the design of the clip, the development of a new manufacturing technology for the fiber-reinforced components as well as first results from the examination of the components in phantom MRI testing is shown.

  15. Gold-wire artifacts on diagnostic radiographs: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Keestra, Johan Anton Jochum; Jacobs, Reinhilde; Quirynen, Marc [Dept. of Oral Health Sciences, KU Leuven and Dentistry, University Hospitals, KU Leuven, Leuven (Belgium)

    2014-03-15

    This report described a case in which diagnostic radiographs showed irregular dense radiopaque strings and curved lines in the head and neck area. These artifacts could lead to misinterpretation since they may obscure anatomical structures and/or mask critical structures/pathologies. A more detailed history of the patient indicated that these strings originated from a facelift procedure in which a gold-wire technique was used. Considering that such intervention may cause a radiodiagnostic burden, it should be included in the anamnesis prior to radiography.

  16. Flexible Capacitive Electrodes for Minimizing Motion Artifacts in Ambulatory Electrocardiograms

    Directory of Open Access Journals (Sweden)

    Jeong Su Lee

    2014-08-01

    Full Text Available This study proposes the use of flexible capacitive electrodes for reducing motion artifacts in a wearable electrocardiogram (ECG device. The capacitive electrodes have conductive foam on their surface, a shield, an optimal input bias resistor, and guarding feedback. The electrodes are integrated in a chest belt, and the acquired signals are transmitted wirelessly for ambulatory heart rate monitoring. We experimentally validated the electrode performance with subjects standing and walking on a treadmill at speeds of up to 7 km/h. The results confirmed the highly accurate heart rate detection capacity of the developed system and its feasibility for daily-life ECG monitoring.

  17. Metal Artifact Reduction Magnetic Resonance Imaging Around Arthroplasty Implants: The Negative Effect of Long Echo Trains on the Implant-Related Artifact.

    Science.gov (United States)

    Kumar, Neil M; de Cesar Netto, Cesar; Schon, Lew C; Fritz, Jan

    2017-05-01

    Long echo train length (ETL) is an often recommended but unproven technique to decrease metal artifacts on magnetic resonance imaging (MRI) scans. Therefore, we quantitatively and qualitatively assessed the effects of ETL on metal artifact on MRI scans using a cobalt-chromium-containing arthroplasty implant system. Using a total ankle arthroplasty system implanted into a human cadaver ankle and a clinical 1.5 T MRI system, turbo spin echo (TSE) pulse sequences were acquired with ETL ranging from 3 to 23 and receiver bandwidth (BW) from 100 to 750 Hz/pixel, whereas effective echo time and spatial resolution were controlled. A compressed sensing slice encoding for metal artifact correction TSE prototype pulse sequence was used as reference standard. End points included the total implant-related artifact area and implant-related signal void areas. Two raters evaluated the overall image quality and preference across varying BW and ETL. Two-factor analysis of variance, Friedman test, Kruskal-Wallis test, and Pearson correlation were used. P values of less than 0.05 were considered statistically significant. The total implant-related artifact area ranged from 0.119 for compressed sensing slice encoding for metal artifact correction (BW, 600 Hz/pixel; ETL, 3) to 0.265 for TSE (BW, 100 Hz/pixel; ETL, 23). Longer ETL significantly increases the total implant-related artifact area (P = 0.0004), whereas it decreased with increasing BW (P ETL (P < 0.0001). High receiver BW is the most effective parameter for reduction of arthroplasty implant-induced metal artifact on MRI scans, whereas in contradiction to prevalent notions, long echo trains fail to reduce implant-related metal artifacts, but in fact cause degradation of image quality around the implant with resultant larger appearing total metal artifacts.

  18. Reference-Free Removal of EEG-fMRI Ballistocardiogram Artifacts with Harmonic Regression

    Science.gov (United States)

    Krishnaswamy, Pavitra; Bonmassar, Giorgio; Poulsen, Catherine; Pierce, Eric T; Purdon, Patrick L.; Brown, Emery N.

    2016-01-01

    Combining electroencephalogram (EEG) recording and functional magnetic resonance imaging (fMRI) offers the potential for imaging brain activity with high spatial and temporal resolution. This potential remains limited by the significant ballistocardiogram (BCG) artifacts induced in the EEG by cardiac pulsation-related head movement within the magnetic field. We model the BCG artifact using a harmonic basis, pose the artifact removal problem as a local harmonic regression analysis, and develop an efficient maximum likelihood algorithm to estimate and remove BCG artifacts. Our analysis paradigm accounts for time-frequency overlap between the BCG artifacts and neurophysiologic EEG signals, and tracks the spatiotemporal variations in both the artifact and the signal. We evaluate performance on: simulated oscillatory and evoked responses constructed with realistic artifacts; actual anesthesia-induced oscillatory recordings; and actual visual evoked potential recordings. In each case, the local harmonic regression analysis effectively removes the BCG artifacts, and recovers the neurophysiologic EEG signals. We further show that our algorithm outperforms commonly used reference-based and component analysis techniques, particularly in low SNR conditions, the presence of significant time-frequency overlap between the artifact and the signal, and/or large spatiotemporal variations in the BCG. Because our algorithm does not require reference signals and has low computational complexity, it offers a practical tool for removing BCG artifacts from EEG data recorded in combination with fMRI. PMID:26151100

  19. Artifact removal in co-registered EEG/fMRI by selective average subtraction.

    Science.gov (United States)

    Gonçalves, S I; Pouwels, P J W; Kuijer, J P A; Heethaar, R M; de Munck, J C

    2007-11-01

    Co-registration of EEG (electroencephalogram) and fMRI (functional magnetic resonance imaging) remains a challenge due to the large artifacts induced on the EEG by the MR (magnetic resonance) sequence magnetic fields. Thus, we present an algorithm, based on the average-subtraction method, which is able to correct EEG data for gradient and pulse artifacts. MR sequence timing parameters are estimated from the EEG data and both slice and volume artifact templates are subtracted from the data. A clustering algorithm is proposed to account for the variability of the pulse artifact. The algorithm is able to keep the spontaneous EEG as well as visual evoked potentials (VEPs), while removing gradient and pulse artifacts with only a subtraction of selectively averaged data. In the frequency domain, the artifact frequencies are strongly attenuated. Estimated MR sequence time parameters showed that the correction is extremely sensitive to the slice time value. Pulse artifact clustering showed that most of the variability is due to the time jitter of the pulse artifact markers. Selective subtraction of averages in combination with proper time alignment is enough to remove most of the MR-induced artifacts. Clean EEG can be obtained from raw signals that are corrupted by MR-induced artifacts during simultaneous EEG-fMRI scanning without using dedicated hardware to synchronize EEG and fMRI clocks.

  20. Artifacts in magnetic resonance imaging and computed tomography caused by dental materials.

    Directory of Open Access Journals (Sweden)

    Thomas Klinke

    Full Text Available BACKGROUND: Artifacts caused by dental restorations, such as dental crowns, dental fillings and orthodontic appliances, are a common problem in MRI and CT scans of the head and neck. The aim of this in-vitro study was to identify and evaluate the artifacts produced by different dental restoration materials in CT and MRI images. METHODS: Test samples of 44 materials (Metal and Non-Metal commonly used in dental restorations were fabricated and embedded with reference specimens in gelatin moulds. MRI imaging of 1.5T and CT scan were performed on the samples and evaluated in two dimensions. Artifact size and distortions were measured using a digital image analysis software. RESULTS: In MRI, 13 out of 44 materials produced artifacts, while in CT 41 out of 44 materials showed artifacts. Artifacts produced in both MRI and CT images were categorized according to the size of the artifact. SIGNIFICANCE: Metal based restoration materials had strong influence on CT and less artifacts in MRI images. Rare earth elements such as Ytterbium trifluoride found in composites caused artifacts in both MRI and CT. Recognizing these findings would help dental materials manufacturers and developers to produce materials which can cause less artifacts in MRI and CT images.

  1. SU-E-I-38: Improved Metal Artifact Correction Using Adaptive Dual Energy Calibration

    Energy Technology Data Exchange (ETDEWEB)

    Dong, X; Elder, E; Roper, J; Dhabaan, A [Winship Cancer Institute of Emory University (United States)

    2015-06-15

    Purpose: The empirical dual energy calibration (EDEC) method corrects for beam-hardening artifacts, but shows limited performance on metal artifact correction. In this work, we propose an adaptive dual energy calibration (ADEC) method to correct for metal artifacts. Methods: The empirical dual energy calibration (EDEC) method corrects for beam-hardening artifacts, but shows limited performance on metal artifact correction. In this work, we propose an adaptive dual energy calibration (ADEC) method to correct for metal artifacts. Results: Highly attenuating copper rods cause severe streaking artifacts on standard CT images. EDEC improves the image quality, but cannot eliminate the streaking artifacts. Compared to EDEC, the proposed ADEC method further reduces the streaking resulting from metallic inserts and beam-hardening effects and obtains material decomposition images with significantly improved accuracy. Conclusion: We propose an adaptive dual energy calibration method to correct for metal artifacts. ADEC is evaluated with the Shepp-Logan phantom, and shows superior metal artifact correction performance. In the future, we will further evaluate the performance of the proposed method with phantom and patient data.

  2. Gaussian diffusion sinogram inpainting for X-ray CT metal artifact reduction.

    Science.gov (United States)

    Peng, Chengtao; Qiu, Bensheng; Li, Ming; Guan, Yihui; Zhang, Cheng; Wu, Zhongyi; Zheng, Jian

    2017-01-05

    Metal objects implanted in the bodies of patients usually generate severe streaking artifacts in reconstructed images of X-ray computed tomography, which degrade the image quality and affect the diagnosis of disease. Therefore, it is essential to reduce these artifacts to meet the clinical demands. In this work, we propose a Gaussian diffusion sinogram inpainting metal artifact reduction algorithm based on prior images to reduce these artifacts for fan-beam computed tomography reconstruction. In this algorithm, prior information that originated from a tissue-classified prior image is used for the inpainting of metal-corrupted projections, and it is incorporated into a Gaussian diffusion function. The prior knowledge is particularly designed to locate the diffusion position and improve the sparsity of the subtraction sinogram, which is obtained by subtracting the prior sinogram of the metal regions from the original sinogram. The sinogram inpainting algorithm is implemented through an approach of diffusing prior energy and is then solved by gradient descent. The performance of the proposed metal artifact reduction algorithm is compared with two conventional metal artifact reduction algorithms, namely the interpolation metal artifact reduction algorithm and normalized metal artifact reduction algorithm. The experimental datasets used included both simulated and clinical datasets. By evaluating the results subjectively, the proposed metal artifact reduction algorithm causes fewer secondary artifacts than the two conventional metal artifact reduction algorithms, which lead to severe secondary artifacts resulting from impertinent interpolation and normalization. Additionally, the objective evaluation shows the proposed approach has the smallest normalized mean absolute deviation and the highest signal-to-noise ratio, indicating that the proposed method has produced the image with the best quality. No matter for the simulated datasets or the clinical datasets, the

  3. Classroom Climate among Teacher Education Mathematics Students

    Directory of Open Access Journals (Sweden)

    Polemer M. Cuarto

    2015-11-01

    Full Text Available Classroom climate has gained prominence as recent studies revealed its potentials as an effective mediator in the various motivational factors as well as an antecedent of academic performance outcome of the students. This descriptive-correlational study determined the level of classroom climate dimensions among teacher education students specializing in Mathematics at Mindoro State College of Agriculture and Technology. Employing a self-structured questionnaire adapted to the WIHIC (What Is Happening In this Class questionnaire, the surveyed data were treated statistically using Pearson’s r. Result showed that there was high level of classroom climate among the respondents in their Mathematics classes in both teacher-directed and student-directed dimensions specifically in terms of equity, teacher support, cohesiveness, involvement, responsibility and task orientation. Also, it revealed that equity and teacher support were both positively related to the students-directed classroom climate dimensions. With these results, teachers are seen to be very significant determinants of the climate in the classroom. Relevant to this, the study recommended that faculty should develop effective measures to enhance classroom climate dimensions such as equity and teacher support to address the needs of diverse studentsdespite large size classes. Moreover, faculty should provide greater opportunitiesfor the students to achieve higher level of responsibility, involvement, cohesiveness, and task orientation as these could motivate them to develop positive learning attitude, perform to the best of their ability, as well as maximize their full potential in school.

  4. Investigation and analysis of human body thermal comfort in classroom

    Science.gov (United States)

    Zhai, Xue

    2017-05-01

    In this survey, we selected the 11th building of North China Electric Power University as the research object. Data were measured and distributed on each floor. We record the temperature of the classroom, humidity, wind speed, average radiation temperature and other environmental parameters. And we used spare time to create a questionnaire survey of the subjective feeling of the survey, to get everyone in the classroom TSV (hot feeling vote value) and TCV (thermal comfort vote). We analyzed the test data and survey data. What's more we discuss and reflect on the thermal comfort of the human body in different indoor temperature atmospheres.

  5. Perceptual distortion measure for edgelike artifacts in image sequences

    Science.gov (United States)

    Yeh, Edmund M.; Kokaram, Anil C.; Kingsbury, Nick G.

    1998-07-01

    This paper presents an objective perceptual distortion measure quantifying the visibility of edge-like blocking artifacts in coded image sequences resulting from popular transform coding techniques. The prime motivation for this work is the awareness that properties of the human visual system should be central to the design and evaluation of image coding algorithms. The perceptual metric is the output of a visual model incorporating both the spatial and temporal characteristics of the visual system. Parameters of the model are based on results from a number of visual experiments in which sensitivities to simulated blocking artifacts were measured under various spatio-temporal background conditions. The visual model takes a pair of original and distorted sequences as inputs. Distortions are calculated along the vertical and horizontal directions. Visibility dependencies on spatial, temporal and motion activities of the background are incorporated using linear filtering and motion estimation. Pixel-based distortions are combined over local spatial and temporal regions to generate an overall distortion measure for each orientation. The final model output is the sum of the vertical and horizontal distortion measures. The model was applied to coded image sequences and the resulting distortion measures were compared to outcomes of subjective ranking tests. Results indicate that the perceptual distortion measure agrees well with human evaluation.

  6. Rigid motion artifact reduction in CT using frequency domain analysis.

    Science.gov (United States)

    Zhang, Yuan; Zhang, Liyi; Sun, Yunshan

    2017-01-01

    It is often unrealistic to assume that the subject remains stationary during a computed tomography (CT) imaging scan. A patient rigid motion can be decomposed into a translation and a rotation around an origin. How to minimize the motion impact on image quality is important. To eliminate artifacts caused by patient rigid motion during a CT scan, this study investigated a new method based on frequency domain analysis to estimate and compensate motion impact. Motion parameters was first determined by the magnitude correlation of projections in frequency domain. Then, the estimated parameters were applied to compensate for the motion effects in the reconstruction process. Finally, this method was extended to helical CT. In fan-beam CT experiments, the simulation results showed that the proposed method was more accurate and faster on the performance of motion estimation than using Helgason-Ludwig consistency condition method (HLCC). Furthermore, the reconstructed images on both simulated and human head experiments indicated that the proposed method yielded superior results in artifact reduction. The proposed method is a new tool for patient motion compensation, with a potential for practical application. It is not only applicable to motion correction in fan-beam CT imaging, but also to helical CT.

  7. Motion Artifact Quantification and Sensor Fusion for Unobtrusive Health Monitoring

    Directory of Open Access Journals (Sweden)

    Christoph Hoog Antink

    2017-12-01

    Full Text Available Sensors integrated into objects of everyday life potentially allow unobtrusive health monitoring at home. However, since the coupling of sensors and subject is not as well-defined as compared to a clinical setting, the signal quality is much more variable and can be disturbed significantly by motion artifacts. One way of tackling this challenge is the combined evaluation of multiple channels via sensor fusion. For robust and accurate sensor fusion, analyzing the influence of motion on different modalities is crucial. In this work, a multimodal sensor setup integrated into an armchair is presented that combines capacitively coupled electrocardiography, reflective photoplethysmography, two high-frequency impedance sensors and two types of ballistocardiography sensors. To quantify motion artifacts, a motion protocol performed by healthy volunteers is recorded with a motion capture system, and reference sensors perform cardiorespiratory monitoring. The shape-based signal-to-noise ratio SNR S is introduced and used to quantify the effect on motion on different sensing modalities. Based on this analysis, an optimal combination of sensors and fusion methodology is developed and evaluated. Using the proposed approach, beat-to-beat heart-rate is estimated with a coverage of 99.5% and a mean absolute error of 7.9 ms on 425 min of data from seven volunteers in a proof-of-concept measurement scenario.

  8. Mascara--an unsuspected cause of magnetic resonance imaging artifact.

    Science.gov (United States)

    Smith, F W; Crosher, G A

    1985-01-01

    It is well recognised that metals, especially iron, will cause artifacts in magnetic resonance (MR) images. Hitherto it has not been recognised that some facial cosmetics contain magnetic materials, in sufficient quantities to cause artifacts. We report a case of a 25-year-old female who had MR images of her orbits made while wearing mascara eye makeup. The resultant images showed distortion of the signal over the anterior aspect of both eyes. Examination following the removal of the eye makeup resulted in the acquisition of normal images. The typical ingredients of mascara are natural and synthetic waxes, glycerine, water, kaolin, preservatives, polymer film formers and pigments. A wide range of pigments may be used, especially iron oxide, which is a constituent of both brown and blue mascara. In addition it is likely that a number of mascaras will be contaminated with heavy metals. As a result of this observation we now ensure that all patients who are undergoing MR imaging of the head, remove all facial cosmetics as well as any jewelry prior to imaging.

  9. Social web artifacts for boosting recommenders theory and implementation

    CERN Document Server

    Ziegler, Cai-Nicolas

    2013-01-01

    Recommender systems, software programs that learn from human behavior and make predictions of what products we are expected to appreciate and purchase, have become an integral part of our everyday life. They proliferate across electronic commerce around the globe and exist for virtually all sorts of consumable goods, such as books, movies, music, or clothes. At the same time, a new evolution on the Web has started to take shape, commonly known as the “Web 2.0” or the “Social Web”: Consumer-generated media has become rife, social networks have emerged and are pulling significant shares of Web traffic. In line with these developments, novel information and knowledge artifacts have become readily available on the Web, created by the collective effort of millions of people. This textbook presents approaches to exploit the new Social Web fountain of knowledge, zeroing in first and foremost on two of those information artifacts, namely classification taxonomies and trust networks. These two are used to impr...

  10. Games as an Interactive Classroom Technique: Perceptions of Corporate Trainers, College Instructors and Students

    Science.gov (United States)

    Kumar, Rita; Lightner, Robin

    2007-01-01

    This two-part study investigates perceptions of interactive classroom teaching techniques for adult learning. In the first part of the study 62 college faculty members and 45 corporate trainers were surveyed about their teaching and training methods. The survey had two main objectives: to determine rates of classroom techniques used, and to…

  11. Assertive classroom management strategies and students’ performance: The case of EFL classroom

    Directory of Open Access Journals (Sweden)

    Mohammad Aliakbari

    2015-12-01

    Full Text Available Ample research findings support the effective role that classroom management strategies play in enhancing students’ learning. Drawing upon Iranian high school teachers’ classroom management strategies, this article is intended to examine the extent to which these teachers follow assertive classroom management strategies and if these strategies affect students’ performance. Conducting a survey including 123 female students, it was found out that Iranian teachers apply classroom management strategies of organization, teaching management, teacher–student relationship, and teacher punishment–rewards (consequences with varying degrees. In the results section, Pearson correlation is applied between students’ achievement and each part of teacher management strategies. Finally, a positive relationship between teachers’ assertiveness and students’ performance was approved. The findings led to implications for in-service training programs for EFL teachers.

  12. Understanding Curriculum, Instruction and Assessment within Eighth Grade Science Classrooms for Special Needs Students

    Science.gov (United States)

    Riedell, Kate Elizabeth

    also provided an in-depth interview as part of the data collection. This comprehensive set of over 200 pieces of data, which includes observations and interviews, as well as artifacts and annotations from the ePortfolios, was analyzed using a grounded theory approach (Strauss & Corbin, 1990). Six central themes emerged from the data. The findings indicated that teachers incorporated some elements of differentiation, personalization and a limited number of components under UDL to support all learners, including students with special needs. There was no indication that the teachers implemented individualization. In other words, there was limited evidence that teachers planned specifically for meeting the needs of students with a specific disability; rather, they focused on collectively meeting the needs of all learners. They recognized the importance of accounting for student motivation and sought to provide hands-on, authentic learning opportunities to motivate and engage students. Yet, they did not survey and/or ask students for their perception of their classroom experiences. While teachers did utilize the electronic portfolio and found it valuable to varying degrees, they indicated that collaboration and visiting other classrooms were essential to their professional development. Implications from this study include (1) ensuring that teachers understand the differences among differentiation, personalization, individualization and universal design for learning; (2) training for teachers on how to properly differentiate, personalize and individualize instruction, as well as how to implement universal design for learning; (3) providing teachers with follow-up support within the classroom to properly implement the approaches mentioned above; (4) training for teachers on the importance of eliciting students' perceptions and how to gauge those perceptions; (5) properly disseminating information to policymakers on the realities of the classrooms and the challenges in

  13. Susceptibility artifacts of pediatric dental stainless steel crowns in magnetic resonance tomography

    OpenAIRE

    Kaleth, Peer

    2017-01-01

    This study was designed to investigate whether stainless steel crowns show significant susceptibility artifacts in magnetic resonance imaging (MRI) and whether these artifacts make it necessary to remove these crowns before an MRI examination. Furthermore, this study analyzes whether different commercially available crowns, which vary in their composition, cause different artifact intensity levels in MRI and whether a shortening and bending of the crown margin leads to more extensive artif...

  14. A Framework for the Assessment of Temporal Artifacts in Medium Frame-Rate Binary Video Halftones

    OpenAIRE

    Hamood-Ur Rehman; Evans, Brian L.

    2010-01-01

    Display of a video having a higher number of bits per pixel than that available on the display device requires quantization prior to display. Video halftoning performs this quantization so as to reduce visibility of certain artifacts. In many cases, visibility of one set of artifacts is decreased at the expense of increasing the visibility of another set. In this paper, we focus on two key temporal artifacts, flicker and dirty-window-effect, in binary video halftones. We quantify the visibil...

  15. Noncontact ECG recording system with real time capacitance measurement for motion artifact reduction.

    Science.gov (United States)

    Torfs, Tom; Chen, Yun-Hsuan; Kim, Hyejung; Yazicioglu, Refet Firat

    2014-10-01

    A system for noncontact ECG recording is proposed that measures the real time electrode-body capacitance concurrently with the ECG as a reference signal for motion artifact reduction. Simultaneous recordings of these two signals from the human body in the presence of electrode motion artifacts are shown and an adaptive least-mean-squares (LMS) filtering algorithm run on these signals is demonstrated to be able to reduce the severity of certain types of electrode motion artifacts.

  16. Mathematical approach to recover EEG brain signals with artifacts by means of Gram-Schmidt transform

    Science.gov (United States)

    Runnova, A. E.; Zhuravlev, M. O.; Koronovskiy, A. A.; Hramov, A. E.

    2017-04-01

    A novel method for removing oculomotor artifacts on electroencephalographical signals is proposed and based on the orthogonal Gram-Schmidt transform using electrooculography data. The method has shown high efficiency removal of artifacts caused by spontaneous movements of the eyeballs (about 95-97% correct remote oculomotor artifacts). This method may be recommended for multi-channel electroencephalography data processing in an automatic on-line in a variety of psycho-physiological experiments.

  17. A dialectical take on artifact ecologies and the physical - digital divide

    DEFF Research Database (Denmark)

    Bødker, Susanne; Klokmose, Clemens Nylandsted

    In this position paper, we will present and discuss our understanding of artifact ecologies as we have developed it, rooted in activity theoretical HCI and dialectical thinking . Our basis is in the Human-Artifact Model, as well as well as cases where we have worked with artifact ecologies...... in analysis and design of computer mediated activity. The paper concludes with a positioning of our perspective vis-a-vis the notions of natural and blended interaction and the physical-digital divide...

  18. Classroom Management through English

    OpenAIRE

    Doyle, Shane

    2009-01-01

    This article aims to examine the problems both foreign and Japanese English Language teachers may have in the classroom. Classroom management through English can be a daunting prospect for both Japanese and non-Japanese language teachers. How to clearly put boundaries in place that students will understand and respect is a problem many educators face. This article deals with problematic issues in classroom management and offers advice and guidance on how these issues can be solved.

  19. A platform-independent method to reduce CT truncation artifacts using discriminative dictionary representations.

    Science.gov (United States)

    Chen, Yang; Budde, Adam; Li, Ke; Li, Yinsheng; Hsieh, Jiang; Chen, Guang-Hong

    2017-01-01

    When the scan field of view (SFOV) of a CT system is not large enough to enclose the entire cross-section of the patient, or the patient needs to be positioned partially outside the SFOV for certain clinical applications, truncation artifacts often appear in the reconstructed CT images. Many truncation artifact correction methods perform extrapolations of the truncated projection data based on certain a priori assumptions. The purpose of this work was to develop a novel CT truncation artifact reduction method that directly operates on DICOM images. The blooming of pixel values associated with truncation was modeled using exponential decay functions, and based on this model, a discriminative dictionary was constructed to represent truncation artifacts and nonartifact image information in a mutually exclusive way. The discriminative dictionary consists of a truncation artifact subdictionary and a nonartifact subdictionary. The truncation artifact subdictionary contains 1000 atoms with different decay parameters, while the nonartifact subdictionary contains 1000 independent realizations of Gaussian white noise that are exclusive with the artifact features. By sparsely representing an artifact-contaminated CT image with this discriminative dictionary, the image was separated into a truncation artifact-dominated image and a complementary image with reduced truncation artifacts. The artifact-dominated image was then subtracted from the original image with an appropriate weighting coefficient to generate the final image with reduced artifacts. This proposed method was validated via physical phantom studies and retrospective human subject studies. Quantitative image evaluation metrics including the relative root-mean-square error (rRMSE) and the universal image quality index (UQI) were used to quantify the performance of the algorithm. For both phantom and human subject studies, truncation artifacts at the peripheral region of the SFOV were effectively reduced, revealing

  20. Enhanced detection of artifacts in EEG data using higher-order statistics and independent component analysis.

    Science.gov (United States)

    Delorme, Arnaud; Sejnowski, Terrence; Makeig, Scott

    2007-02-15

    Detecting artifacts produced in EEG data by muscle activity, eye blinks and electrical noise is a common and important problem in EEG research. It is now widely accepted that independent component analysis (ICA) may be a useful tool for isolating artifacts and/or cortical processes from electroencephalographic (EEG) data. We present results of simulations demonstrating that ICA decomposition, here tested using three popular ICA algorithms, Infomax, SOBI, and FastICA, can allow more sensitive automated detection of small non-brain artifacts than applying the same detection methods directly to the scalp channel data. We tested the upper bound performance of five methods for detecting various types of artifacts by separately optimizing and then applying them to artifact-free EEG data into which we had added simulated artifacts of several types, ranging in size from thirty times smaller (-50 dB) to the size of the EEG data themselves (0 dB). Of the methods tested, those involving spectral thresholding were most sensitive. Except for muscle artifact detection where we found no gain of using ICA, all methods proved more sensitive when applied to the ICA-decomposed data than applied to the raw scalp data: the mean performance for ICA was higher and situated at about two standard deviations away from the performance distribution obtained on raw data. We note that ICA decomposition also allows simple subtraction of artifacts accounted for by single independent components, and/or separate and direct examination of the decomposed non-artifact processes themselves.

  1. Dealing with noise and physiological artifacts in human EEG recordings: empirical mode methods

    Science.gov (United States)

    Runnova, Anastasiya E.; Grubov, Vadim V.; Khramova, Marina V.; Hramov, Alexander E.

    2017-04-01

    In the paper we propose the new method for removing noise and physiological artifacts in human EEG recordings based on empirical mode decomposition (Hilbert-Huang transform). As physiological artifacts we consider specific oscillatory patterns that cause problems during EEG analysis and can be detected with additional signals recorded simultaneously with EEG (ECG, EMG, EOG, etc.) We introduce the algorithm of the proposed method with steps including empirical mode decomposition of EEG signal, choosing of empirical modes with artifacts, removing these empirical modes and reconstructing of initial EEG signal. We show the efficiency of the method on the example of filtration of human EEG signal from eye-moving artifacts.

  2. A standardized evaluation of artifacts from metallic compounds during fast MR imaging

    DEFF Research Database (Denmark)

    Murakami, Shumei; Verdonschot, Rinus G; Kataoka, Miyoshi

    2016-01-01

    OBJECTIVE: Metallic compounds present in the oral and maxillofacial regions (OMR) cause large artifacts during MR scanning. We quantitatively assessed these artifacts embedded within a phantom according to standards set by the American Society for Testing and Materials (ASTM). MATERIALS AND METHODS...... according to the ASTM-F2119 standard and artifact volumes were assessed using OsiriX MD software Results: Tukey-Kramer post-hoc tests were used for statistical comparisons. For most materials, scanning sequences eliciting artifact volumes in the following (ascending) order FSE-T1/FSE-T2

  3. What causes the "wet diaper" artifact? computed tomography and magnetic resonance observations.

    Science.gov (United States)

    Markowitz, Richard I; Altes, Talissa A; Jaramillo, Diego

    2009-01-01

    Disposable diapers contain super absorbent polymers that absorb liquid. A radio-dense artifact, seen when the diaper is wet, obscures radiographic information but is frequently misinterpreted. Our purpose was to examine this artifact on CT and MR to further clarify and explain its origin. Dry and wet diapers were imaged. Fluid within the wet diaper appeared as small nodules with characteristics of bound water. No free water was detected. Dry diapers produced no artifact. The artifact is most undesirable on radiographs, but does not obscure diagnostic information on cross-sectional imaging. It should not be misinterpreted as contrast.

  4. Flipped Classroom Approach

    Directory of Open Access Journals (Sweden)

    Fezile Ozdamli

    2016-07-01

    Full Text Available Flipped classroom is an active, student-centered approach that was formed to increase the quality of period within class. Generally this approach whose applications are done mostly in Physical Sciences, also attracts the attention of educators and researchers in different disciplines recently. Flipped classroom learning which wide-spreads rapidly in the world, is not well recognized in our country. That is why the aim of study is to attract attention to its potential in education field and provide to make it recognize more by educators and researchers. With this aim, in the study what flipped classroom approach is, flipped classroom technology models, its advantages and limitations were explained.

  5. Wireless Accelerometer for Neonatal MRI Motion Artifact Correction

    Directory of Open Access Journals (Sweden)

    Martyn Paley

    2017-01-01

    Full Text Available A wireless accelerometer has been used in conjunction with a dedicated 3T neonatal MRI system installed on a Neonatal Intensive Care Unit to measure in-plane rotation which is a common problem with neonatal MRI. Rotational data has been acquired in real-time from phantoms simultaneously with MR images which shows that the wireless accelerometer can be used in close proximity to the MR system. No artifacts were observed on the MR images from the accelerometer or from the MR system on the accelerometer output. Initial attempts to correct the raw data using the measured rotational angles have been performed, but further work will be required to make a robust correction algorithm.

  6. Removal of blink artifacts in single channel EEG.

    Science.gov (United States)

    Szibbo, Dyana; Luo, An; Sullivan, Thomas J

    2012-01-01

    Blinks are one of the main sources of distortion in electroencephalographic (EEG) data. Discarding blink-contaminated segments of EEG data would result in considerable information loss when interpreting and analyzing data. This study presents a simple method of blink filtering using a Savitzky-Golay (SG) smoothing filter and compares it to Independent Component Analysis (ICA), a widely accepted method of blink removal. The SG-based blink filtering method arose from the need for blink removal in EEG systems with a low number of channels and limited processing power, specifically reading from the forehead location where the blink disturbance is severe. Real and simulated data were investigated with respect to the method's performance. Using correlation and mutual information to measure performance, the results reveal that the SG-based method can effectively remove blink artifacts and produces results comparable to those obtained using ICA.

  7. Big Data between audiovisual displays, artifacts, and aesthetic experience

    DEFF Research Database (Denmark)

    Bjørnsten, Thomas

    2016-01-01

    of large data sets – or Big Data – into the sphere of art and the aesthetic. Central to the discussion here is the analysis of how different structuring principles of data and the discourses that surround these principles shape our perception of data. This discussion involves considerations on various......This article discusses artistic practices and artifacts that are occupied with exploring data through visualization and sonification strategies as well as with translating data into materially solid formats and embodied processes. By means of these examples the overall aim of the article...... is to critically question how and whether such artistic practices can eventually lead to the experience and production of knowledge that could not otherwise be obtained via more traditional ways of data representation. The article, thus, addresses both the problems and possibilities entailed in extending the use...

  8. Trail Trees: Living Artifacts (Vivifacts of Eastern North America

    Directory of Open Access Journals (Sweden)

    Nicholas C. Kawa

    2015-09-01

    Full Text Available Living trees historically modified by human populations, oftentimes referred to as “culturally modified trees” (CMTs, are found throughout the North American landscape. In eastern North America specifically, indigenous populations bent thousands of trees to mark trails, and some of these still exist in the region today. In this article, we present a synthesis of current knowledge on trail trees, including their speculated functions, formation, and selection. We also examine the theoretical implications of these living artifacts (or vivifacts and how they may open new avenues for investigation by archaeologists, environmental historians, and ethnobiologists. To conclude, we make a call for expanded public recognition and documentation of trail trees, discussing the need for their incorporation into forest and park management plans.

  9. MORAL TECHNIQUES. FORENSIC ANTHROPOLOGY AND ITS ARTIFACTS FOR DOING GOOD

    Directory of Open Access Journals (Sweden)

    GABRIEL GATTI

    2013-01-01

    Full Text Available In many of its applications forensic anthropology is a singular discipline, midway between a bare techno-scientific exercise and a militant involvement in overcoming situations marked by human rights violations. Today, riding on an intense and transnational wave of humanitarian sensitivity, forensic anthropology has acquired a significant scientific, moral and media status, and has become a front line scientific-technical practice in the human rights field at the planetary level. This text, which analyzes some of the artifacts with which forensic anthropology represents and works on its object, aims to understand this discipline through the concept of moral technique, which, in my understanding, captures the particular tensions of this form of working for good.

  10. A Model for Geometry-Dependent Errors in Length Artifacts.

    Science.gov (United States)

    Sawyer, Daniel; Parry, Brian; Phillips, Steven; Blackburn, Chris; Muralikrishnan, Bala

    2012-01-01

    We present a detailed model of dimensional changes in long length artifacts, such as step gauges and ball bars, due to bending under gravity. The comprehensive model is based on evaluation of the gauge points relative to the neutral bending surface. It yields the errors observed when the gauge points are located off the neutral bending surface of a bar or rod but also reveals the significant error associated with out-of-straightness of a bar or rod even if the gauge points are located in the neutral bending surface. For example, one experimental result shows a length change of greater than 1.5 µm on a 1 m ball bar with an out-of-straightness of 0.4 mm. This and other results are in agreement with the model presented in this paper.

  11. Optimizing complexity measures for FMRI data: algorithm, artifact, and sensitivity.

    Directory of Open Access Journals (Sweden)

    Denis Rubin

    Full Text Available INTRODUCTION: Complexity in the brain has been well-documented at both neuronal and hemodynamic scales, with increasing evidence supporting its use in sensitively differentiating between mental states and disorders. However, application of complexity measures to fMRI time-series, which are short, sparse, and have low signal/noise, requires careful modality-specific optimization. METHODS: HERE WE USE BOTH SIMULATED AND REAL DATA TO ADDRESS TWO FUNDAMENTAL ISSUES: choice of algorithm and degree/type of signal processing. Methods were evaluated with regard to resilience to acquisition artifacts common to fMRI as well as detection sensitivity. Detection sensitivity was quantified in terms of grey-white matter contrast and overlap with activation. We additionally investigated the variation of complexity with activation and emotional content, optimal task length, and the degree to which results scaled with scanner using the same paradigm with two 3T magnets made by different manufacturers. Methods for evaluating complexity were: power spectrum, structure function, wavelet decomposition, second derivative, rescaled range, Higuchi's estimate of fractal dimension, aggregated variance, and detrended fluctuation analysis. To permit direct comparison across methods, all results were normalized to Hurst exponents. RESULTS: Power-spectrum, Higuchi's fractal dimension, and generalized Hurst exponent based estimates were most successful by all criteria; the poorest-performing measures were wavelet, detrended fluctuation analysis, aggregated variance, and rescaled range. CONCLUSIONS: Functional MRI data have artifacts that interact with complexity calculations in nontrivially distinct ways compared to other physiological data (such as EKG, EEG for which these measures are typically used. Our results clearly demonstrate that decisions regarding choice of algorithm, signal processing, time-series length, and scanner have a significant impact on the reliability and

  12. Clinical evaluation of TOF versus non-TOF on PET artifacts in simultaneous PET/MR: a dual centre experience

    Energy Technology Data Exchange (ETDEWEB)

    Voert, Edwin E.G.W. ter [University Hospital Zurich, Department of Nuclear Medicine, Zurich (Switzerland); University of Zurich, Zurich (Switzerland); Veit-Haibach, Patrick [University Hospital Zurich, Department of Nuclear Medicine, Zurich (Switzerland); University of Zurich, Zurich (Switzerland); University Hospital Zurich, Department of Diagnostic and Interventional Radiology, Zurich (Switzerland); Ahn, Sangtae [GE Global Research, Niskayuna, NY (United States); Wiesinger, Florian [GE Global Research, Muenchen (Germany); Khalighi, M.M.; Delso, Gaspar [GE Healthcare, Waukesha, WI (United States); Levin, Craig S. [Stanford University, Department of Radiology, Molecular Imaging Program at Stanford, Stanford, CA (United States); Iagaru, Andrei H. [Stanford University, Department of Radiology, Division of Nuclear Medicine and Molecular Imaging, Stanford, CA (United States); Zaharchuk, Greg [Stanford University, Department of Radiology, Neuroradiology, Stanford, CA (United States); Huellner, Martin [University Hospital Zurich, Department of Nuclear Medicine, Zurich (Switzerland); University of Zurich, Zurich (Switzerland); University Hospital Zurich, Department of Neuroradiology, Zurich (Switzerland)

    2017-07-15

    Our objective was to determine clinically the value of time-of-flight (TOF) information in reducing PET artifacts and improving PET image quality and accuracy in simultaneous TOF PET/MR scanning. A total 65 patients who underwent a comparative scan in a simultaneous TOF PET/MR scanner were included. TOF and non-TOF PET images were reconstructed, clinically examined, compared and scored. PET imaging artifacts were categorized as large or small implant-related artifacts, as dental implant-related artifacts, and as implant-unrelated artifacts. Differences in image quality, especially those related to (implant) artifacts, were assessed using a scale ranging from 0 (no artifact) to 4 (severe artifact). A total of 87 image artifacts were found and evaluated. Four patients had large and eight patients small implant-related artifacts, 27 patients had dental implants/fillings, and 48 patients had implant-unrelated artifacts. The average score was 1.14 ± 0.82 for non-TOF PET images and 0.53 ± 0.66 for TOF images (p < 0.01) indicating that artifacts were less noticeable when TOF information was included. Our study indicates that PET image artifacts are significantly mitigated with integration of TOF information in simultaneous PET/MR. The impact is predominantly seen in patients with significant artifacts due to metal implants. (orig.)

  13. A robust post-processing workflow for datasets with motion artifacts in diffusion kurtosis imaging.

    Directory of Open Access Journals (Sweden)

    Xianjun Li

    Full Text Available PURPOSE: The aim of this study was to develop a robust post-processing workflow for motion-corrupted datasets in diffusion kurtosis imaging (DKI. MATERIALS AND METHODS: The proposed workflow consisted of brain extraction, rigid registration, distortion correction, artifacts rejection, spatial smoothing and tensor estimation. Rigid registration was utilized to correct misalignments. Motion artifacts were rejected by using local Pearson correlation coefficient (LPCC. The performance of LPCC in characterizing relative differences between artifacts and artifact-free images was compared with that of the conventional correlation coefficient in 10 randomly selected DKI datasets. The influence of rejected artifacts with information of gradient directions and b values for the parameter estimation was investigated by using mean square error (MSE. The variance of noise was used as the criterion for MSEs. The clinical practicality of the proposed workflow was evaluated by the image quality and measurements in regions of interest on 36 DKI datasets, including 18 artifact-free (18 pediatric subjects and 18 motion-corrupted datasets (15 pediatric subjects and 3 essential tremor patients. RESULTS: The relative difference between artifacts and artifact-free images calculated by LPCC was larger than that of the conventional correlation coefficient (p<0.05. It indicated that LPCC was more sensitive in detecting motion artifacts. MSEs of all derived parameters from the reserved data after the artifacts rejection were smaller than the variance of the noise. It suggested that influence of rejected artifacts was less than influence of noise on the precision of derived parameters. The proposed workflow improved the image quality and reduced the measurement biases significantly on motion-corrupted datasets (p<0.05. CONCLUSION: The proposed post-processing workflow was reliable to improve the image quality and the measurement precision of the derived parameters on motion

  14. Flipped Classroom Approach

    Science.gov (United States)

    Ozdamli, Fezile; Asiksoy, Gulsum

    2016-01-01

    Flipped classroom is an active, student-centered approach that was formed to increase the quality of period within class. Generally this approach whose applications are done mostly in Physical Sciences, also attracts the attention of educators and researchers in different disciplines recently. Flipped classroom learning which wide-spreads rapidly…

  15. Relationships in Inclusive Classrooms

    Science.gov (United States)

    Santos, Graça Duarte; Sardinha, Susana; Reis, Silvia

    2016-01-01

    Climate in the classroom is one of the determining factors in the development of practices in Inclusive Education. Many factors contribute to the climate in the classroom. However, there are predominance on affective-relational factors, with impact on action, norms and values, social interactions and learning processes. In this paper, the authors…

  16. Classroom -RE-SONANCE

    Indian Academy of Sciences (India)

    in a classroom situation. We may suggest strategies for dealing with them, or invite responses, or both. "Classroom" is equally a forum for raising broader issues and sharing personal experiences and viewpoints on matters related to· teaching and learning science. Logarithm and agM. In [1] we had discussed the evaluation.

  17. Defining Authentic Classroom Assessment

    Science.gov (United States)

    Frey, Bruce B.; Schmitt, Vicki L.; Allen, Justin P.

    2012-01-01

    A commonly advocated best practice for classroom assessment is to make the assessments authentic. Authentic is often used as meaning the mirroring of real-world tasks or expectations. There is no consensus, however, in the actual definition of the term or the characteristics of an authentic classroom assessment. Sometimes, the realistic component…

  18. Classroom Assessment in Action

    Science.gov (United States)

    Shermis, Mark D.; DiVesta, Francis J.

    2011-01-01

    "Classroom Assessment in Action" clarifies the multi-faceted roles of measurement and assessment and their applications in a classroom setting. Comprehensive in scope, Shermis and Di Vesta explain basic measurement concepts and show students how to interpret the results of standardized tests. From these basic concepts, the authors then…

  19. Mathematics difficulties & classroom leadership

    DEFF Research Database (Denmark)

    Schmidt, Maria Christina Secher

    2016-01-01

    . The findings suggest that the teachers’ pedagogical choices and actions support an active learning environment for students in diverse learning needs, and that the teachers practise dimensions of inclusive classroom leadership that are known to be successful for teaching mathematics to all students. Despite......This article investigates possible links between inclusion, students, for whom mathematics is extensively difficult, and classroom leadership through a case study on teaching strategies and student participation in four classrooms at two different primary schools in Denmark. Three sets of results...... are presented: 1) descriptions of the teachers’ classroom leadership to include all their students in the learning community, 2) the learning community produced by stated and practiced rules for teaching and learning behavior, 3) the classroom behavior of students who experience difficulties with mathematics...

  20. An Astronomical Misconceptions Survey

    Science.gov (United States)

    LoPresto, Michael C.; Murrell, Steven R.

    2011-01-01

    Misconceptions that students bring with them to the introductory science classroom plague every area of science and are especially prevalent in astronomy. One way to identify and possibly dispel some of these misconceptions is through the use of a misconceptions survey. The following is a report on the development, implementation, and some early…

  1. Pellets or maggots? – A case report on artifacts in forensic medicine

    Directory of Open Access Journals (Sweden)

    Tanuj Kanchan

    2015-12-01

    Full Text Available Forensic medicine specialists use their expertise to identify artifacts and avoid its misinterpretation. This is vital in carrying out justice as any misinterpretation of findings can derail the investigation. We report a case where an artifact resembled a firearm/shotgun injury that raised a suspicion of an alleged homicide.

  2. Reduction hybrid artifacts of EMG-EOG in electroencephalography evoked by prefrontal transcranial magnetic stimulation

    Science.gov (United States)

    Bai, Yang; Wan, Xiaohong; Zeng, Ke; Ni, Yinmei; Qiu, Lirong; Li, Xiaoli

    2016-12-01

    Objective. When prefrontal-transcranial magnetic stimulation (p-TMS) performed, it may evoke hybrid artifact mixed with muscle activity and blink activity in EEG recordings. Reducing this kind of hybrid artifact challenges the traditional preprocessing methods. We aim to explore method for the p-TMS evoked hybrid artifact removal. Approach. We propose a novel method used as independent component analysis (ICA) post processing to reduce the p-TMS evoked hybrid artifact. Ensemble empirical mode decomposition (EEMD) was used to decompose signal into multi-components, then the components were separated with artifact reduced by blind source separation (BSS) method. Three standard BSS methods, ICA, independent vector analysis, and canonical correlation analysis (CCA) were tested. Main results. Synthetic results showed that EEMD-CCA outperformed others as ICA post processing step in hybrid artifacts reduction. Its superiority was clearer when signal to noise ratio (SNR) was lower. In application to real experiment, SNR can be significantly increased and the p-TMS evoked potential could be recovered from hybrid artifact contaminated signal. Our proposed method can effectively reduce the p-TMS evoked hybrid artifacts. Significance. Our proposed method may facilitate future prefrontal TMS-EEG researches.

  3. Automated Classification and Removal of EEG Artifacts with SVM and Wavelet-ICA.

    Science.gov (United States)

    Sai, Chong Yeh; Mokhtar, Norrima; Arof, Hamzah; Cumming, Paul; Iwahashi, Masahiro

    2017-07-04

    Brain electrical activity recordings by electroencephalography (EEG) are often contaminated with signal artifacts. Procedures for automated removal of EEG artifacts are frequently sought for clinical diagnostics and brain computer interface (BCI) applications. In recent years, a combination of independent component analysis (ICA) and discrete wavelet transform (DWT) has been introduced as standard technique for EEG artifact removal. However, in performing the wavelet-ICA procedure, visual inspection or arbitrary thresholding may be required for identifying artifactual components in the EEG signal. We now propose a novel approach for identifying artifactual components separated by wavelet-ICA using a pre-trained support vector machine (SVM). Our method presents a robust and extendable system that enables fully automated identification and removal of artifacts from EEG signals, without applying any arbitrary thresholding. Using test data contaminated by eye blink artifacts, we show that our method performed better in identifying artifactual components than did existing thresholding methods. Furthermore, wavelet-ICA in conjunction with SVM successfully removed target artifacts, while largely retaining the EEG source signals of interest. We propose a set of features including kurtosis, variance, Shannon's entropy and range of amplitude as training and test data of SVM to identify eye blink artifacts in EEG signals. This combinatorial method is also extendable to accommodate multiple types of artifacts present in multi-channel EEG. We envision future research to explore other descriptive features corresponding to other types of artifactual components.

  4. Archaeology through Computational Linguistics: Inscription Statistics Predict Excavation Sites of Indus Valley Artifacts

    Science.gov (United States)

    Recchia, Gabriel L.; Louwerse, Max M.

    2016-01-01

    Computational techniques comparing co-occurrences of city names in texts allow the relative longitudes and latitudes of cities to be estimated algorithmically. However, these techniques have not been applied to estimate the provenance of artifacts with unknown origins. Here, we estimate the geographic origin of artifacts from the Indus Valley…

  5. Evaluation of MRI artifacts at 3 Tesla for 38 commonly used cosmetics.

    Science.gov (United States)

    Escher, Kirin; Shellock, Frank G

    2013-06-01

    To evaluate MRI artifacts at 3-Tesla for 38 commonly used cosmetics. Thirty-eight cosmetics (16, nail polishes; 5, eyeliners; 3, mascaras; 10, eye shadows; 1, lip gloss; 1, body lotion; 1, body glitter, and 1, hair loss concealer) underwent evaluation for MRI artifacts at 3-Tesla. The cosmetics were applied a copper-sulfate-filled, phantom and initially assessed using a "screening" gradient echo (GRE) pulse sequence. Of the 38 different cosmetics, 14 (37%) exhibited artifacts. For these 14 cosmetics, additional characterization of artifacts was performed using a GRE pulse sequence. A qualitative scale was applied to characterize the artifact size. Artifacts were observed, as follows: 2, nail polishes; 5, eyeliners; 3, mascaras; 3, eye shadows; 1, hair loss concealer. Artifact size ranged from small (eye shadow) to very large (hair loss concealer) and tended to be associated with the presence of iron oxide or other metal-based ingredient. Commonly used cosmetics caused artifacts that may create issues if the area of interest is the same as where the cosmetic was applied or if its presence was unknown, thus, potentially causing it to be construed as pathology. Therefore, these findings have important implications for patients referred for MRI examinations. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Spectral CT metal artifact reduction with an optimization-based reconstruction algorithm

    Science.gov (United States)

    Gilat Schmidt, Taly; Barber, Rina F.; Sidky, Emil Y.

    2017-03-01

    Metal objects cause artifacts in computed tomography (CT) images. This work investigated the feasibility of a spectral CT method to reduce metal artifacts. Spectral CT acquisition combined with optimization-based reconstruction is proposed to reduce artifacts by modeling the physical effects that cause metal artifacts and by providing the flexibility to selectively remove corrupted spectral measurements in the spectral-sinogram space. The proposed Constrained `One-Step' Spectral CT Image Reconstruction (cOSSCIR) algorithm directly estimates the basis material maps while enforcing convex constraints. The incorporation of constraints on the reconstructed basis material maps is expected to mitigate undersampling effects that occur when corrupted data is excluded from reconstruction. The feasibility of the cOSSCIR algorithm to reduce metal artifacts was investigated through simulations of a pelvis phantom. The cOSSCIR algorithm was investigated with and without the use of a third basis material representing metal. The effects of excluding data corrupted by metal were also investigated. The results demonstrated that the proposed cOSSCIR algorithm reduced metal artifacts and improved CT number accuracy. For example, CT number error in a bright shading artifact region was reduced from 403 HU in the reference filtered backprojection reconstruction to 33 HU using the proposed algorithm in simulation. In the dark shading regions, the error was reduced from 1141 HU to 25 HU. Of the investigated approaches, decomposing the data into three basis material maps and excluding the corrupted data demonstrated the greatest reduction in metal artifacts.

  7. The Role of Historical Intuitions in Children's and Adults' Naming of Artifacts

    Science.gov (United States)

    Gutheil, Grant; Bloom, Paul; Valderrama, Nohemy; Freedman, Rebecca

    2004-01-01

    It is commonly assumed that artifacts are named solely on the basis of properties they currently possess; in particular, their appearance and function. The experiments presented here explore the alternative proposal that the history of an artifact plays some role in how it is named. In three experiments, children between the ages of 4 and 9 years…

  8. A robust post-processing workflow for datasets with motion artifacts in diffusion kurtosis imaging.

    Science.gov (United States)

    Li, Xianjun; Yang, Jian; Gao, Jie; Luo, Xue; Zhou, Zhenyu; Hu, Yajie; Wu, Ed X; Wan, Mingxi

    2014-01-01

    The aim of this study was to develop a robust post-processing workflow for motion-corrupted datasets in diffusion kurtosis imaging (DKI). The proposed workflow consisted of brain extraction, rigid registration, distortion correction, artifacts rejection, spatial smoothing and tensor estimation. Rigid registration was utilized to correct misalignments. Motion artifacts were rejected by using local Pearson correlation coefficient (LPCC). The performance of LPCC in characterizing relative differences between artifacts and artifact-free images was compared with that of the conventional correlation coefficient in 10 randomly selected DKI datasets. The influence of rejected artifacts with information of gradient directions and b values for the parameter estimation was investigated by using mean square error (MSE). The variance of noise was used as the criterion for MSEs. The clinical practicality of the proposed workflow was evaluated by the image quality and measurements in regions of interest on 36 DKI datasets, including 18 artifact-free (18 pediatric subjects) and 18 motion-corrupted datasets (15 pediatric subjects and 3 essential tremor patients). The relative difference between artifacts and artifact-free images calculated by LPCC was larger than that of the conventional correlation coefficient (pworkflow improved the image quality and reduced the measurement biases significantly on motion-corrupted datasets (pworkflow was reliable to improve the image quality and the measurement precision of the derived parameters on motion-corrupted DKI datasets. The workflow provided an effective post-processing method for clinical applications of DKI in subjects with involuntary movements.

  9. X-ray CT Metal Artifact Reduction Using Wavelet Domain L-0 Sparse Regularization

    NARCIS (Netherlands)

    Mehranian, Abolfazl; Ay, Mohammad Reza; Rahmim, Arman; Zaidi, Habib

    X-ray computed tomography (CT) imaging of patients with metallic implants usually suffers from streaking metal artifacts. In this paper, we propose a new projection completion metal artifact reduction (MAR) algorithm by formulating the completion of missing projections as a regularized inverse

  10. 3D Prior Image Constrained Projection Completion for X-ray CT Metal Artifact Reduction

    NARCIS (Netherlands)

    Mehranian, Abolfazl; Ay, Mohammad Reza; Rahmim, Arman; Zaidi, Habib

    2013-01-01

    The presence of metallic implants in the body of patients undergoing X-ray computed tomography (CT) examinations often results insevere streaking artifacts that degrade image quality. In this work, we propose a new metal artifact reduction (MAR) algorithm for 2D fan-beam and 3D cone-beam CT based on

  11. Automated removal of EKG artifact from EEG data using independent component analysis and continuous wavelet transformation.

    Science.gov (United States)

    Hamaneh, Mehdi Bagheri; Chitravas, Numthip; Kaiboriboon, Kitti; Lhatoo, Samden D; Loparo, Kenneth A

    2014-06-01

    The electrical potential produced by the cardiac activity sometimes contaminates electroencephalogram (EEG) recordings, resulting in spiky activities that are referred to as electrocardiographic (EKG) artifact. For a variety of reasons it is often desirable to automatically detect and remove these artifacts. Especially, for accurate source localization of epileptic spikes in an EEG recording from a patient with epilepsy, it is of great importance to remove any concurrent artifact. Due to similarities in morphology between the EKG artifacts and epileptic spikes, any automated artifact removal algorithm must have an extremely low false-positive rate in addition to a high detection rate. In this paper, an automated algorithm for removal of EKG artifact is proposed that satisfies such criteria. The proposed method, which uses combines independent component analysis and continuous wavelet transformation, uses both temporal and spatial characteristics of EKG related potentials to identify and remove the artifacts. The method outperforms algorithms that use general statistical features such as entropy and kurtosis for artifact rejection.

  12. Combining EEG and eye tracking: identification, characterization, and correction of eye movement artifacts in electroencephalographic data

    Science.gov (United States)

    Plöchl, Michael; Ossandón, José P.; König, Peter

    2012-01-01

    Eye movements introduce large artifacts to electroencephalographic recordings (EEG) and thus render data analysis difficult or even impossible. Trials contaminated by eye movement and blink artifacts have to be discarded, hence in standard EEG-paradigms subjects are required to fixate on the screen. To overcome this restriction, several correction methods including regression and blind source separation have been proposed. Yet, there is no automated standard procedure established. By simultaneously recording eye movements and 64-channel-EEG during a guided eye movement paradigm, we investigate and review the properties of eye movement artifacts, including corneo-retinal dipole changes, saccadic spike potentials and eyelid artifacts, and study their interrelations during different types of eye- and eyelid movements. In concordance with earlier studies our results confirm that these artifacts arise from different independent sources and that depending on electrode site, gaze direction, and choice of reference these sources contribute differently to the measured signal. We assess the respective implications for artifact correction methods and therefore compare the performance of two prominent approaches, namely linear regression and independent component analysis (ICA). We show and discuss that due to the independence of eye artifact sources, regression-based correction methods inevitably over- or under-correct individual artifact components, while ICA is in principle suited to address such mixtures of different types of artifacts. Finally, we propose an algorithm, which uses eye tracker information to objectively identify eye-artifact related ICA-components (ICs) in an automated manner. In the data presented here, the algorithm performed very similar to human experts when those were given both, the topographies of the ICs and their respective activations in a large amount of trials. Moreover it performed more reliable and almost twice as effective than human experts

  13. Neuroscientists' classroom visits positively impact student attitudes.

    Directory of Open Access Journals (Sweden)

    Janet L Fitzakerley

    Full Text Available The primary recommendation of the 2010 President's Council of Advisors on Science and Technology report on K-12 education was to inspire more students so that they are motivated to study science. Scientists' visits to classrooms are intended to inspire learners and increase their interest in science, but verifications of this impact are largely qualitative. Our primary goal was to evaluate the impact of a longstanding Brain Awareness classroom visit program focused on increasing learners understanding of their own brains. Educational psychologists have established that neuroscience training sessions can improve academic performance and shift attitudes of students from a fixed mindset to a growth mindset. Our secondary goal was to determine whether short interactive Brain Awareness scientist-in-the-classroom sessions could similarly alter learners' perceptions of their own potential to learn. Teacher and student surveys were administered in 4(th-6(th grade classrooms throughout Minnesota either before or after one-hour Brain Awareness sessions that engaged students in activities related to brain function. Teachers rated the Brain Awareness program as very valuable and said that the visits stimulated students' interest in the brain and in science. Student surveys probed general attitudes towards science and their knowledge of neuroscience concepts (particularly the ability of the brain to change. Significant favorable improvements were found on 10 of 18 survey statements. Factor analyses of 4805 responses demonstrated that Brain Awareness presentations increased positive attitudes toward science and improved agreement with statements related to growth mindset. Overall effect sizes were small, consistent with the short length of the presentations. Thus, the impact of Brain Awareness presentations was positive and proportional to the efforts expended, demonstrating that short, scientist-in-the-classroom visits can make a positive contribution to

  14. Neuroscientists' classroom visits positively impact student attitudes.

    Science.gov (United States)

    Fitzakerley, Janet L; Michlin, Michael L; Paton, John; Dubinsky, Janet M

    2013-01-01

    The primary recommendation of the 2010 President's Council of Advisors on Science and Technology report on K-12 education was to inspire more students so that they are motivated to study science. Scientists' visits to classrooms are intended to inspire learners and increase their interest in science, but verifications of this impact are largely qualitative. Our primary goal was to evaluate the impact of a longstanding Brain Awareness classroom visit program focused on increasing learners understanding of their own brains. Educational psychologists have established that neuroscience training sessions can improve academic performance and shift attitudes of students from a fixed mindset to a growth mindset. Our secondary goal was to determine whether short interactive Brain Awareness scientist-in-the-classroom sessions could similarly alter learners' perceptions of their own potential to learn. Teacher and student surveys were administered in 4(th)-6(th) grade classrooms throughout Minnesota either before or after one-hour Brain Awareness sessions that engaged students in activities related to brain function. Teachers rated the Brain Awareness program as very valuable and said that the visits stimulated students' interest in the brain and in science. Student surveys probed general attitudes towards science and their knowledge of neuroscience concepts (particularly the ability of the brain to change). Significant favorable improvements were found on 10 of 18 survey statements. Factor analyses of 4805 responses demonstrated that Brain Awareness presentations increased positive attitudes toward science and improved agreement with statements related to growth mindset. Overall effect sizes were small, consistent with the short length of the presentations. Thus, the impact of Brain Awareness presentations was positive and proportional to the efforts expended, demonstrating that short, scientist-in-the-classroom visits can make a positive contribution to primary school

  15. Neuroscientists’ Classroom Visits Positively Impact Student Attitudes

    Science.gov (United States)

    Fitzakerley, Janet L.; Michlin, Michael L.; Paton, John; Dubinsky, Janet M.

    2013-01-01

    The primary recommendation of the 2010 President’s Council of Advisors on Science and Technology report on K-12 education was to inspire more students so that they are motivated to study science. Scientists’ visits to classrooms are intended to inspire learners and increase their interest in science, but verifications of this impact are largely qualitative. Our primary goal was to evaluate the impact of a longstanding Brain Awareness classroom visit program focused on increasing learners understanding of their own brains. Educational psychologists have established that neuroscience training sessions can improve academic performance and shift attitudes of students from a fixed mindset to a growth mindset. Our secondary goal was to determine whether short interactive Brain Awareness scientist-in-the-classroom sessions could similarly alter learners’ perceptions of their own potential to learn. Teacher and student surveys were administered in 4th-6th grade classrooms throughout Minnesota either before or after one-hour Brain Awareness sessions that engaged students in activities related to brain function. Teachers rated the Brain Awareness program as very valuable and said that the visits stimulated students’ interest in the brain and in science. Student surveys probed general attitudes towards science and their knowledge of neuroscience concepts (particularly the ability of the brain to change). Significant favorable improvements were found on 10 of 18 survey statements. Factor analyses of 4805 responses demonstrated that Brain Awareness presentations increased positive attitudes toward science and improved agreement with statements related to growth mindset. Overall effect sizes were small, consistent with the short length of the presentations. Thus, the impact of Brain Awareness presentations was positive and proportional to the efforts expended, demonstrating that short, scientist-in-the-classroom visits can make a positive contribution to primary school

  16. A Review of the Performance of Artifact Filtering Algorithms for Cardiopulmonary Resuscitation

    Directory of Open Access Journals (Sweden)

    Yushun Gong

    2013-01-01

    Full Text Available Various filtering strategies have been adopted and investigated to suppress the cardiopulmonary resuscitation (CPR artifact. In this article, two types of artifact removal methods are reviewed: one is the method that removes CPR artifact using only ECG signals, and the other is the method with additional reference signals, such as acceleration, compression depth and transthoracic impedance. After filtering, the signal-to-noise ratio is improved from 0 dB to greater than 2.8 dB, the sensitivity is increased to > 90% as recommended by the American Heart Association, whereas the specificity was far from the recommended 95%, which is considered to be the major drawback of the available artifact removal methods. The overall performance of the adaptive filtering methods with additional reference signal outperforms the methods using only ECG signals. Further research should focus on the refinement of artifact filtering methods and the improvement of shock advice algorithms with the presence of CPR.

  17. FORCe: Fully Online and Automated Artifact Removal for Brain-Computer Interfacing.

    Science.gov (United States)

    Daly, Ian; Scherer, Reinhold; Billinger, Martin; Müller-Putz, Gernot

    2015-09-01

    A fully automated and online artifact removal method for the electroencephalogram (EEG) is developed for use in brain-computer interfacing (BCI). The method (FORCe) is based upon a novel combination of wavelet decomposition, independent component analysis, and thresholding. FORCe is able to operate on a small channel set during online EEG acquisition and does not require additional signals (e.g., electrooculogram signals). Evaluation of FORCe is performed offline on EEG recorded from 13 BCI particpants with cerebral palsy (CP) and online with three healthy participants. The method outperforms the state-of the-art automated artifact removal methods Lagged Auto-Mutual Information Clustering (LAMIC) and Fully Automated Statistical Thresholding for EEG artifact Rejection (FASTER), and is able to remove a wide range of artifact types including blink, electromyogram (EMG), and electrooculogram (EOG) artifacts.

  18. A Framework for the Assessment of Temporal Artifacts in Medium Frame-Rate Binary Video Halftones

    Directory of Open Access Journals (Sweden)

    Rehman Hamood-Ur

    2010-01-01

    Full Text Available Display of a video having a higher number of bits per pixel than that available on the display device requires quantization prior to display. Video halftoning performs this quantization so as to reduce visibility of certain artifacts. In many cases, visibility of one set of artifacts is decreased at the expense of increasing the visibility of another set. In this paper, we focus on two key temporal artifacts, flicker and dirty-window-effect, in binary video halftones. We quantify the visibility of these two artifacts when the video halftone is displayed at medium frame rates (15 to 30 frames per second. We propose new video halftoning methods to reduce visibility of these artifacts. The proposed contributions are (1 an enhanced measure of perceived flicker, (2 a new measure of perceived dirty-window-effect, (3 a new video halftoning method to reduce flicker, and (4 a new video halftoning method to reduce dirty-window-effect.

  19. Filtration of human EEG recordings from physiological artifacts with empirical mode method

    Science.gov (United States)

    Grubov, Vadim V.; Runnova, Anastasiya E.; Khramova, Marina V.

    2017-03-01

    In the paper we propose the new method for dealing with noise and physiological artifacts in experimental human EEG recordings. The method is based on analysis of EEG signals with empirical mode decomposition (Hilbert-Huang transform). We consider noises and physiological artifacts on EEG as specific oscillatory patterns that cause problems during EEG analysis and can be detected with additional signals recorded simultaneously with EEG (ECG, EMG, EOG, etc.) We introduce the algorithm of the method with following steps: empirical mode decomposition of EEG signal, choosing of empirical modes with artifacts, removing empirical modes with artifacts, reconstruction of the initial EEG signal. We test the method on filtration of experimental human EEG signals from eye-moving artifacts and show high efficiency of the method.

  20. Cancellation of artifacts in ECG signals using a normalized adaptive neural filter.

    Science.gov (United States)

    Wu, Yunfeng; Rangayyan, Rangaraj M; Ng, Sin-Chun

    2007-01-01

    Denoising electrocardiographic (ECG) signals is an essential procedure prior to their analysis. In this paper, we present a normalized adaptive neural filter (NANF) for cancellation of artifacts in ECG signals. The normalized filter coefficients are updated by the steepest-descent algorithm; the adaptation process is designed to minimize the difference between second-order estimated output values and the desired artifact-free ECG signals. Empirical results with benchmark data show that the adaptive artifact canceller that includes the NANF can effectively remove muscle-contraction artifacts and high-frequency noise in ambulatory ECG recordings, leading to a high signal-to-noise ratio. Moreover, the performance of the NANF in terms of the root-mean-squared error, normalized correlation coefficient, and filtered artifact entropy is significantly better than that of the popular least-mean-square (LMS) filter.

  1. MR Image Based Approach for Metal Artifact Reduction in X-Ray CT

    Directory of Open Access Journals (Sweden)

    Andras Anderla

    2013-01-01

    Full Text Available For decades, computed tomography (CT images have been widely used to discover valuable anatomical information. Metallic implants such as dental fillings cause severe streaking artifacts which significantly degrade the quality of CT images. In this paper, we propose a new method for metal-artifact reduction using complementary magnetic resonance (MR images. The method exploits the possibilities which arise from the use of emergent trimodality systems. The proposed algorithm corrects reconstructed CT images. The projected data which is affected by dental fillings is detected and the missing projections are replaced with data obtained from a corresponding MR image. A simulation study was conducted in order to compare the reconstructed images with images reconstructed through linear interpolation, which is a common metal-artifact reduction technique. The results show that the proposed method is successful in reducing severe metal artifacts without introducing significant amount of secondary artifacts.

  2. Clinical evaluation of TOF versus non-TOF on PET artifacts in simultaneous PET/MR: a dual centre experience.

    Science.gov (United States)

    Ter Voert, Edwin E G W; Veit-Haibach, Patrick; Ahn, Sangtae; Wiesinger, Florian; Khalighi, M Mehdi; Levin, Craig S; Iagaru, Andrei H; Zaharchuk, Greg; Huellner, Martin; Delso, Gaspar

    2017-07-01

    Our objective was to determine clinically the value of time-of-flight (TOF) information in reducing PET artifacts and improving PET image quality and accuracy in simultaneous TOF PET/MR scanning. A total 65 patients who underwent a comparative scan in a simultaneous TOF PET/MR scanner were included. TOF and non-TOF PET images were reconstructed, clinically examined, compared and scored. PET imaging artifacts were categorized as large or small implant-related artifacts, as dental implant-related artifacts, and as implant-unrelated artifacts. Differences in image quality, especially those related to (implant) artifacts, were assessed using a scale ranging from 0 (no artifact) to 4 (severe artifact). A total of 87 image artifacts were found and evaluated. Four patients had large and eight patients small implant-related artifacts, 27 patients had dental implants/fillings, and 48 patients had implant-unrelated artifacts. The average score was 1.14 ± 0.82 for non-TOF PET images and 0.53 ± 0.66 for TOF images (p PET image artifacts are significantly mitigated with integration of TOF information in simultaneous PET/MR. The impact is predominantly seen in patients with significant artifacts due to metal implants.

  3. Real-time EEG artifact correction during fMRI using ICA.

    Science.gov (United States)

    Mayeli, Ahmad; Zotev, Vadim; Refai, Hazem; Bodurka, Jerzy

    2016-12-01

    Simultaneous acquisition of EEG and fMRI data results in EEG signal contamination by imaging (MR) and ballistocardiogram (BCG) artifacts. Artifact correction of EEG data for real-time applications, such as neurofeedback studies, is the subject of ongoing research. To date, average artifact subtraction (AAS) is the most widespread real-time method used to partially remove BCG and imaging artifacts without requiring extra hardware equipment; no alternative software-only real time methods for removing EEG artifacts are available. We introduce a novel, improved approach for real-time EEG artifact correction during fMRI (rtICA). The rtICA is based on real time independent component analysis (ICA) and it is employed following the AAS method. The rtICA was implemented and validated during EEG and fMRI experiments on healthy subjects. Our results demonstrate that the rtICA employed after the rtAAS can obtain 98.4% success in detection of eye blinks, 4.4 times larger INPS reductions compared to RecView-corrected data, and effectively reduce motion artifacts, as well as imaging and muscle artifacts, in real time on six healthy subjects. We compared our real-time artifact reduction results with the rtAAS and various offline methods using multiple evaluation metrics, including power analysis. Importantly, the rtICA does not affect brain neuronal signals as reflected in EEG bands of interest, including the alpha band. A novel real-time ICA method was proposed for improving the EEG quality signal recorded during fMRI acquisition. The results show substantial reduction of different types of artifacts using real-time ICA method. Copyright © 2016 The Author(s). Published by Elsevier B.V. All rights reserved.

  4. Metal artifact reduction in MRI-based cervical cancer intracavitary brachytherapy

    Science.gov (United States)

    Rao, Yuan James; Zoberi, Jacqueline E.; Kadbi, Mo; Grigsby, Perry W.; Cammin, Jochen; Mackey, Stacie L.; Garcia-Ramirez, Jose; Goddu, S. Murty; Schwarz, Julie K.; Gach, H. Michael

    2017-04-01

    Magnetic resonance imaging (MRI) plays an increasingly important role in brachytherapy planning for cervical cancer. Yet, metal tandem, ovoid intracavitary applicators, and fiducial markers used in brachytherapy cause magnetic susceptibility artifacts in standard MRI. These artifacts may impact the accuracy of brachytherapy treatment and the evaluation of tumor response by misrepresenting the size and location of the metal implant, and distorting the surrounding anatomy and tissue. Metal artifact reduction sequences (MARS) with high bandwidth RF selective excitations and turbo spin-echo readouts were developed for MRI of orthopedic implants. In this study, metal artifact reduction was applied to brachytherapy of cervical cancer using the orthopedic metal artifact reduction (O-MAR) sequence. O-MAR combined MARS features with view angle tilting and slice encoding for metal artifact correction (SEMAC) to minimize in-plane and through-plane susceptibility artifacts. O-MAR improved visualization of the tandem tip on T2 and proton density weighted (PDW) imaging in phantoms and accurately represented the diameter of the tandem. In a pilot group of cervical cancer patients (N  =  7), O-MAR significantly minimized the blooming artifact at the tip of the tandem in PDW MRI. There was no significant difference observed in artifact reduction between the weak (5 kHz, 7 z-phase encodes) and medium (10 kHz, 13 z-phase encodes) SEMAC settings. However, the weak setting allowed a significantly shorter acquisition time than the medium setting. O-MAR also reduced susceptibility artifacts associated with metal fiducial markers so that they appeared on MRI at their true dimensions.

  5. Variability of myocardial perfusion dark rim Gibbs artifacts due to sub-pixel shifts

    Directory of Open Access Journals (Sweden)

    Kellman Peter

    2009-05-01

    Full Text Available Abstract Background Gibbs ringing has been shown as a possible source of dark rim artifacts in myocardial perfusion studies. This type of artifact is usually described as transient, lasting a few heart beats, and localised in random segments of the myocardial wall. Dark rim artifacts are known to be unpredictably variable. This article aims to illustrate that a sub-pixel shift, i.e. a small displacement of the pixels with respect to the endocardial border, can result in different Gibbs ringing and hence different artifacts. Therefore a hypothesis for one cause of dark rim artifact variability is given based on the sub-pixel position of the endocardial border. This article also demonstrates the consequences for Gibbs artifacts when two different methods of image interpolation are applied (post-FFT interpolation, and pre-FFT zero-filling. Results Sub-pixel shifting of in vivo perfusion studies was shown to change the appearance of Gibbs artifacts. This effect was visible in the original uninterpolated images, and in the post-FFT interpolated images. The same shifted data interpolated by pre-FFT zero-filling exhibited much less variability in the Gibbs artifact. The in vivo findings were confirmed by phantom imaging and numerical simulations. Conclusion Unless pre-FFT zero-filling interpolation is performed, Gibbs artifacts are very dependent on the position of the subendocardial wall within the pixel. By introducing sub-pixel shifts relative to the endocardial border, some of the variability of the dark rim artifacts in different myocardial segments, in different patients and from frame to frame during first-pass perfusion due to cardiac and respiratory motion can be explained. Image interpolation by zero-filling can be used to minimize this dependency.

  6. CANDIDATES TEACHERS' CLASSROOM MANAGEMENT SELF-EFFICACY LEVELS

    OpenAIRE

    Süleyman Göksoy

    2016-01-01

    This research aimed to determine the classroom management self-efficacy beliefs of students have been studying in Faculty of Education and students have been maintaining pedagogical formation certificate program. It employed survey model. The study group was composed of 362 trainees who attended to pedagogical formation certificate program in Duzce University in 2015/16 academic year spring term and 255 sophomores, junior and senior class students in Classroom Teaching and Science Teaching De...

  7. Classroom Management and the Librarian

    Science.gov (United States)

    Blackburn, Heidi; Hays, Lauren

    2014-01-01

    As librarians take on more instructional responsibilities, the need for classroom management skills becomes vital. Unfortunately, classroom management skills are not taught in library school and therefore, many librarians are forced to learn how to manage a classroom on the job. Different classroom settings such as one-shot instruction sessions…

  8. Flipping the Classroom

    Science.gov (United States)

    Riendeau, Diane

    2012-11-01

    A recent trend in education is the ``flipped'' or ``reversed'' classroom. In this educational model, students view videos of the lectures as their homework and class time is used for activities and solving problems that might have been assigned as homework in a traditional classroom. Although far from an expert on flipping the classroom, I can see some merit in the idea. When students watch the videos at home, they can start and restart the lecture as often as they like. The lectures are also available for review before the exam. Class time can be used for higher-order questioning, experiments, and problem solving.

  9. Flipped Classroom, active Learning?

    DEFF Research Database (Denmark)

    Andersen, Thomas Dyreborg; Levinsen, Henrik; Philipps, Morten

    2015-01-01

    Action research is conducted in three physics classes over a period of eighteen weeks with the aim of studying the effect of flipped classroom on the pupils agency and learning processes. The hypothesis is that flipped classroom teaching will potentially allocate more time to work actively...... are conducted in three different phases corresponding to different teaching sequences During the first phase the classes are taught as they are usually taught. During the next two phases classes are taught on the basis of a common understanding of the flipped classroom teaching model obtained during a 4 day...

  10. Skin artifact removal technique for breast cancer radar detection

    Science.gov (United States)

    Caorsi, S.; Lenzi, C.

    2016-06-01

    In this paper we propose a new model-based skin artifact cleaning technique with the aim to remove skin reflections with good effectiveness, without introducing significant signal distortions, and without assuming a priori information on the real structure of the breast. The reference cleaning model, constituted by a two-layer geometry skin-adipose tissue, is oriented to all the ultrawideband radar methods able to detect the tumor starting by the knowledge of each trace recorded around the breast. All the radar signal measurements were simulated by using realistic breast models derived from the University of Wisconsin computational electromagnetic laboratory database and the finite difference time domain (FDTD)-based open source software GprMax. First, we have searched for the best configuration for the reference cleaning model with the aim to minimize the distortions introduced on the radar signal. Second, the performance of the proposed cleaning technique has been assessed by using a breast cancer radar detection technique based on the use of artificial neural network (ANN). In order to minimize the signal distortions, we found that it was necessary to use the real skin thickness and the static Debye parameters of both skin and adipose tissue. In such a case the ANN-based radar approach was able to detect the tumor with an accuracy of 87%. By extending the performance assessment also to the case when only average standard values are used to characterize the reference cleaning model, the detection accuracy was of 84%.

  11. Imaging artifact precompensation for spatially multiplexed 3-D displays

    Science.gov (United States)

    Napoli, Joshua; Dey, Sourav R.; Stutsman, Sandy; Cossairt, Oliver S.; Purtell, Thomas J., II; Hill, Samuel L.; Favalora, Gregg E.

    2008-02-01

    We describe a projection system that presents a 20 megapixel image using a single XGA SLM and time-division multiplexing. The system can be configured as a high-resolution 2-D display or a highly multi-view horizontal parallax display. In this paper, we present a technique for characterizing the light transport function of the display and for precompensating the image for the measured transport function. The techniques can improve the effective quality of the display without modifying its optics. Precompensation is achieved by approximately solving a quadratic optimization problem. Compared to a linear filter, this technique is not limited by a fixed kernel size and can propagate image detail to all related pixels. Large pixel-count images are supported through dividing the problem into blocks. A remedy for blocking artifacts is given. Results of the algorithm are presented based on simulations of a display design. The display characterization method is suitable for experimental designs that may be dim and imperfectly aligned. Simulated results of the characterization and precompensation process are presented. RMS and qualitative improvement of display image quality are demonstrated.

  12. Automatic detection of artifacts in converted S3D video

    Science.gov (United States)

    Bokov, Alexander; Vatolin, Dmitriy; Zachesov, Anton; Belous, Alexander; Erofeev, Mikhail

    2014-03-01

    In this paper we present algorithms for automatically detecting issues specific to converted S3D content. When a depth-image-based rendering approach produces a stereoscopic image, the quality of the result depends on both the depth maps and the warping algorithms. The most common problem with converted S3D video is edge-sharpness mismatch. This artifact may appear owing to depth-map blurriness at semitransparent edges: after warping, the object boundary becomes sharper in one view and blurrier in the other, yielding binocular rivalry. To detect this problem we estimate the disparity map, extract boundaries with noticeable differences, and analyze edge-sharpness correspondence between views. We pay additional attention to cases involving a complex background and large occlusions. Another problem is detection of scenes that lack depth volume: we present algorithms for detecting at scenes and scenes with at foreground objects. To identify these problems we analyze the features of the RGB image as well as uniform areas in the depth map. Testing of our algorithms involved examining 10 Blu-ray 3D releases with converted S3D content, including Clash of the Titans, The Avengers, and The Chronicles of Narnia: The Voyage of the Dawn Treader. The algorithms we present enable improved automatic quality assessment during the production stage.

  13. Diagnostic value of chemical shift artifact in distinguishing benign lymphadenopathy

    Energy Technology Data Exchange (ETDEWEB)

    Farshchian, Nazanin, E-mail: farshchian.n@gmail.com [Department of Radiology, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Tamari, Saghar; Farshchian, Negin [Department of Radiology, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Madani, Hamid [Department of Pathology, Imam-Reza Hospital, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Rezaie, Mansour [Department of Biostatistics, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Mohammadi-Motlagh, Hamid-Reza, E-mail: mohammadimotlagh@gmail.com [Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of)

    2011-11-15

    Purpose: Today, distinguishing metastatic lymph nodes from secondary benign inflammatory ones via using non-invasive methods is increasingly favorable. In this study, the diagnostic value of chemical shift artifact (CSA) in magnetic resonance imaging (MRI) was evaluated to distinguish benign lymphadenopathy. Subjects and methods: A prospective intraindividual internal review board-approved study was carried out on 15 men and 15 women having lymphadenopathic lesions in different locations of the body who underwent contrast-enhanced dynamic MR imaging at 1.5 T. Then, the imaging findings were compared with pathology reports, using the statistics analyses. Results: Due to the findings of the CSA existence in MRI, a total of 56.7% of the studied lesions (17 of 30) were identified as benign lesions and the rest were malignant, whereas the pathology reports distinguished twelve malignant and eighteen benign cases. Furthermore, the CSA findings comparing the pathology reports indicated that CSA, with confidence of 79.5%, has a significant diagnostic value to differentiate benign lesions from malignant ones. Conclusion: Our study demonstrated that CSA in MR imaging has a suitable diagnostic potential nearing readiness for clinical trials. Furthermore, CSA seems to be a feasible tool to differentiate benign lymph nodes from malignant ones; however, further studies including larger numbers of patients are required to confirm our results.

  14. An illustrative review to understand and manage metal-induced artifacts in musculoskeletal MRI: a primer and updates

    Energy Technology Data Exchange (ETDEWEB)

    Dillenseger, J.P.; Choquet, P.; Goetz, C.; Bierry, G. [University Hospital of Strasbourg, Medical Imaging Department, Strasbourg (France); Icube, CNRS, University of Strasbourg, Strasbourg (France); University of Strasbourg, Translational Medicine Research Federation, Strasbourg Medical School, Strasbourg (France); Moliere, S. [University Hospital of Strasbourg, Medical Imaging Department, Strasbourg (France); Ehlinger, M. [Icube, CNRS, University of Strasbourg, Strasbourg (France); University of Strasbourg, Translational Medicine Research Federation, Strasbourg Medical School, Strasbourg (France); University Hospital of Strasbourg, Department of Orthopedic Surgery, Strasbourg (France)

    2016-05-15

    This article reviews and explains the basic physical principles of metal-induced MRI artifacts, describes simple ways to reduce them, and presents specific reduction solutions. Artifacts include signal loss, pile-up artifacts, geometric distortion, and failure of fat suppression. Their nature and origins are reviewed and explained though schematic representations that ease the understanding. Then, optimization of simple acquisition parameters is detailed. Lastly, dedicated sequences and options specifically developed to reduce metal artifacts (VAT, SEMAC, and MAVRIC) are explained. (orig.)

  15. Adaptive filtering of ballistocardiogram artifact from EEG signals using the dilated discrete Hermite transform.

    Science.gov (United States)

    Mahadevan, Anandi; Mugler, Dale H; Acharya, Soumyadipta

    2008-01-01

    Electroencephalogram (EEG) signals, when recorded within the strong magnetic field of an MRI scanner are subject to various artifacts, of which the ballistocardiogram (BCG) is one of the prominent ones affecting the quality of the EEG. The BCG artifact varies slightly in shape and amplitude for every cardiac cycle making it difficult to identify and remove. This paper proposes a novel method for the identification and elimination of this artifact using the shape basis functions of the new dilated discrete Hermite transform. In this study, EEG data within and outside the scanner was recorded. On removal of the BCG artifact for the EEG data recorded within the scanner, a significant reduction in amplitude at the frequencies associated with the BCG artifact was observed. In order to quantitatively assess the efficacy of this method, BCG artifact templates were added to segments of EEG signals recorded outside the scanner. These signals, when filtered using the proposed method, had no significant difference (p0.05) from the original signals, indicating that the technique satisfactorily eliminates the BCG artifact and does not introduce any distortions in the original signal. The method is computationally efficient for real-time implementation.

  16. A level set method for cupping artifact correction in cone-beam CT.

    Science.gov (United States)

    Xie, Shipeng; Li, Chunming; Li, Haibo; Ge, Qi

    2015-08-01

    To reduce cupping artifacts and improve the contrast-to-noise ratio in cone-beam computed tomography (CBCT). A level set method is proposed to reduce cupping artifacts in the reconstructed image of CBCT. The authors derive a local intensity clustering property of the CBCT image and define a local clustering criterion function of the image intensities in a neighborhood of each point. This criterion function defines an energy in terms of the level set functions, which represent a segmentation result and the cupping artifacts. The cupping artifacts are estimated as a result of minimizing this energy. The cupping artifacts in CBCT are reduced by an average of 90%. The results indicate that the level set-based algorithm is practical and effective for reducing the cupping artifacts and preserving the quality of the reconstructed image. The proposed method focuses on the reconstructed image without requiring any additional physical equipment, is easily implemented, and provides cupping correction through a single-scan acquisition. The experimental results demonstrate that the proposed method successfully reduces the cupping artifacts.

  17. High-throughput ocular artifact reduction in multichannel electroencephalography (EEG) using component subspace projection.

    Science.gov (United States)

    Ma, Junshui; Bayram, Sevinç; Tao, Peining; Svetnik, Vladimir

    2011-03-15

    After a review of the ocular artifact reduction literature, a high-throughput method designed to reduce the ocular artifacts in multichannel continuous EEG recordings acquired at clinical EEG laboratories worldwide is proposed. The proposed method belongs to the category of component-based methods, and does not rely on any electrooculography (EOG) signals. Based on a concept that all ocular artifact components exist in a signal component subspace, the method can uniformly handle all types of ocular artifacts, including eye-blinks, saccades, and other eye movements, by automatically identifying ocular components from decomposed signal components. This study also proposes an improved strategy to objectively and quantitatively evaluate artifact reduction methods. The evaluation strategy uses real EEG signals to synthesize realistic simulated datasets with different amounts of ocular artifacts. The simulated datasets enable us to objectively demonstrate that the proposed method outperforms some existing methods when no high-quality EOG signals are available. Moreover, the results of the simulated datasets improve our understanding of the involved signal decomposition algorithms, and provide us with insights into the inconsistency regarding the performance of different methods in the literature. The proposed method was also applied to two independent clinical EEG datasets involving 28 volunteers and over 1000 EEG recordings. This effort further confirms that the proposed method can effectively reduce ocular artifacts in large clinical EEG datasets in a high-throughput fashion. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. Methods for artifact detection and removal from scalp EEG: A review.

    Science.gov (United States)

    Islam, Md Kafiul; Rastegarnia, Amir; Yang, Zhi

    2016-11-01

    Electroencephalography (EEG) is the most popular brain activity recording technique used in wide range of applications. One of the commonly faced problems in EEG recordings is the presence of artifacts that come from sources other than brain and contaminate the acquired signals significantly. Therefore, much research over the past 15 years has focused on identifying ways for handling such artifacts in the preprocessing stage. However, this is still an active area of research as no single existing artifact detection/removal method is complete or universal. This article presents an extensive review of the existing state-of-the-art artifact detection and removal methods from scalp EEG for all potential EEG-based applications and analyses the pros and cons of each method. First, a general overview of the different artifact types that are found in scalp EEG and their effect on particular applications are presented. In addition, the methods are compared based on their ability to remove certain types of artifacts and their suitability in relevant applications (only functional comparison is provided not performance evaluation of methods). Finally, the future direction and expected challenges of current research is discussed. Therefore, this review is expected to be helpful for interested researchers who will develop and/or apply artifact handling algorithm/technique in future for their applications as well as for those willing to improve the existing algorithms or propose a new solution in this particular area of research. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  19. An unsupervised eye blink artifact detection method for real-time electroencephalogram processing.

    Science.gov (United States)

    Chang, Won-Du; Lim, Jeong-Hwan; Im, Chang-Hwan

    2016-03-01

    Electroencephalogram (EEG) is easily contaminated by unwanted physiological artifacts, among which electrooculogram (EOG) artifacts due to eye blinking are known to be most dominant. The eye blink artifacts are reported to affect theta and alpha rhythms of frontal EEG signals, and hard to be accurately detected in an unsupervised way due to large individual variability. In this study, we propose a new method for detecting eye blink artifacts automatically in real time without using any labeled training data. The proposed method combined our previous method for detecting eye blink artifacts based on digital filters with an automatic thresholding algorithm. The proposed method was evaluated using EEG data acquired from 24 participants. Two conventional algorithms were implemented and their performances were compared with that of the proposed method. The main contributions of this study are (1) confirming that individual thresholding is necessary for artifact detection, (2) proposing a novel algorithm structure to detect blink artifacts in a real-time environment without any a priori knowledge, and (3) demonstrating that the length of training data can be minimized through the use of a real-time adaption procedure.

  20. AFM and pulsed laser ablation methods for Cultural Heritage: application to archeometric analysis of stone artifacts

    Science.gov (United States)

    Barberio, M.; Veltri, S.; Stranges, F.; Bonanno, A.; Xu, F.; Antici, P.

    2015-09-01

    In this paper, we introduce the use of the atomic force microscope (AFM) and of the pulsed laser ablation as methods for morphological diagnostic with nanoscale precision of archeological artifacts and corrosive patina removal from stone artifacts. We test our methodology on stone artifacts extracted from the Church of Sotterra (located in Calabria, South Italy). The AFM microscopy was compared with different petrographic, chemical, optical and morphological analysis methods for identifying the textural characteristics, evaluating the state of preservation and formulating some hypotheses about the provenance and composition of the impurity patina located on the artifact surfaces. We demonstrate that with the nanometric precision obtained with AFM microscopy, it is possible to distinguish the different states of preservation, much better than using conventional petrographic methods. The surface's roughness is evaluated from very small artifact's fragments, reducing the coring at micrometric scale with a minimal damage to the artworks. After the diagnosis, we performed restoration tests using the pulsed laser ablation (PLA) method and compared it with the more common micro-sandblasting under dry conditions. We find that the PLA is highly effective for the removal of the surficial patina, with a control of a few hundreds of nanometers in the cleaning of surface, without introducing chemical or morphological damages to the artifacts. Moreover, PLA can be easily implemented in underwater conditions; this has the great advantage that stone and pottery artifacts for marine archeological sites do not need to be removed from the site.

  1. A level set method for cupping artifact correction in cone-beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Shipeng; Li, Haibo; Ge, Qi [College of Telecommunications and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu 210003 (China); Li, Chunming, E-mail: li-chunming@hotmail.com [School of Electronic Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu, Sichuan 611731 (China)

    2015-08-15

    Purpose: To reduce cupping artifacts and improve the contrast-to-noise ratio in cone-beam computed tomography (CBCT). Methods: A level set method is proposed to reduce cupping artifacts in the reconstructed image of CBCT. The authors derive a local intensity clustering property of the CBCT image and define a local clustering criterion function of the image intensities in a neighborhood of each point. This criterion function defines an energy in terms of the level set functions, which represent a segmentation result and the cupping artifacts. The cupping artifacts are estimated as a result of minimizing this energy. Results: The cupping artifacts in CBCT are reduced by an average of 90%. The results indicate that the level set-based algorithm is practical and effective for reducing the cupping artifacts and preserving the quality of the reconstructed image. Conclusions: The proposed method focuses on the reconstructed image without requiring any additional physical equipment, is easily implemented, and provides cupping correction through a single-scan acquisition. The experimental results demonstrate that the proposed method successfully reduces the cupping artifacts.

  2. A semi-simulated EEG/EOG dataset for the comparison of EOG artifact rejection techniques

    Directory of Open Access Journals (Sweden)

    Manousos A. Klados

    2016-09-01

    Full Text Available Artifact rejection techniques are used to recover the brain signals underlying artifactual electroencephalographic (EEG segments. Although over the last few years many different artifact rejection techniques have been proposed (http://dx.doi.org/10.1109/JSEN.2011.2115236 [1], http://dx.doi.org/10.1016/j.clinph.2006.09.003 [2], http://dx.doi.org/10.3390/e16126553 [3], none has been established as a gold standard so far, because assessing their performance is difficult and subjective (http://dx.doi.org/10.1109/ITAB.2009.5394295 [4], http://dx.doi.org/10.1016/j.bspc.2011.02.001 [5], http://dx.doi.org/10.1007/978-3-540-89208-3_300. [6]. This limitation is mainly based on the fact that the underlying artifact-free brain signal is unknown, so there is no objective way to measure how close the retrieved signal is to the real one. This article solves the aforementioned problem by presenting a semi-simulated EEG dataset, where artifact-free EEG signals are manually contaminated with ocular artifacts, using a realistic head model. The significant part of this dataset is that it contains the pre-contamination EEG signals, so the brain signals underlying the EOG artifacts are known and thus the performance of every artifact rejection technique can be objectively assessed.

  3. Simultaneous ocular and muscle artifact removal from EEG data by exploiting diverse statistics.

    Science.gov (United States)

    Chen, Xun; Liu, Aiping; Chen, Qiang; Liu, Yu; Zou, Liang; McKeown, Martin J

    2017-09-01

    Electroencephalography (EEG) recordings are frequently contaminated by both ocular and muscle artifacts. These are normally dealt with separately, by employing blind source separation (BSS) techniques relying on either second-order or higher-order statistics (SOS & HOS respectively). When HOS-based methods are used, it is usually in the setting of assuming artifacts are statistically independent to the EEG. When SOS-based methods are used, it is assumed that artifacts have autocorrelation characteristics distinct from the EEG. In reality, ocular and muscle artifacts do not completely follow the assumptions of strict temporal independence to the EEG nor completely unique autocorrelation characteristics, suggesting that exploiting HOS or SOS alone may be insufficient to remove these artifacts. Here we employ a novel BSS technique, independent vector analysis (IVA), to jointly employ HOS and SOS simultaneously to remove ocular and muscle artifacts. Numerical simulations and application to real EEG recordings were used to explore the utility of the IVA approach. IVA was superior in isolating both ocular and muscle artifacts, especially for raw EEG data with low signal-to-noise ratio, and also integrated usually separate SOS and HOS steps into a single unified step. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Ocular and cardiac artifact rejection for real-time analysis in MEG.

    Science.gov (United States)

    Breuer, Lukas; Dammers, Jürgen; Roberts, Timothy P L; Shah, N Jon

    2014-08-15

    Recently, magnetoencephalography (MEG) based real-time brain computing interfaces (BCI) have been developed to enable novel and promising methods for neuroscience research. It is well known that artifact rejection prior to source localization largely enhances the localization accuracy. However, many BCI approaches neglect real-time artifact removal due to its time consuming process. The method (referred to as ocular and cardiac artifact rejection for real-time analysis, OCARTA) is based on constrained independent component analysis (cICA), where a priori information of the underlying source signals is used to optimize and accelerate signal decomposition. Thereby, prior information is incorporated by using the subject's individual cardiac and ocular activity. The algorithm automatically uses different separation strategies depending on the underlying source activity. OCARTA was tested and applied to data from three different but most commonly used MEG systems (4D-Neuroimaging, VSM MedTech Inc. and Elekta Neuromag). Ocular and cardiac artifacts were effectively reduced within one iteration at a time delay of 1ms performed on a standard PC (Intel Core i5-2410M). The artifact rejection results achieved with OCARTA are in line with the results reported for offline ICA-based artifact rejection methods. Due to the fast and subject-specific signal decomposition the new approach introduced here is capable of real-time ocular and cardiac artifact rejection. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Artifact properties of carbon nanotube yarn electrode in magnetic resonance imaging

    Science.gov (United States)

    Jiang, C. Q.; Hao, H. W.; Li, L. M.

    2013-04-01

    Objective. Deep brain stimulating (DBS) is a rapidly developing therapy that can treat many refractory neurological diseases. However, the traditional DBS electrodes which are made of Pt-Ir alloy may induce severe field distortions in magnetic resonance imaging (MRI) which leads to artifacts that will lower the local image quality and cause inconvenience or interference. A novel DBS electrode made from carbon nanotube yarns (CNTYs) is brought up to reduce the artifacts. This study is therefore to evaluate the artifact properties of the novel electrode. Approach. We compared its MR artifact characteristics with the Pt-Ir electrode in water phantom, including its artifact behaviors at different orientations as well as at various off-center positions, using both spin echo (SE) and gradient echo (GE) sequences, and confirmed its performance in vivo. Main results. The results in phantom showed that the CNTY electrode artifacts reduced as much as 62% and 74% on GE and SE images, respectively, compared to the Pt-Ir one. And consistent behaviors were confirmed in vivo. The susceptibility difference was identified as the dominant cause in producing artifacts. Significance. Employing the CNTY electrode may generate much less field distortion in the vicinity, improve local MR image quality and possibly be beneficial in various aspects.

  6. In the Classroom

    Science.gov (United States)

    History and Social Science Teacher, 1975

    1975-01-01

    Using cartoons and comic strips to teach the concept of social class and newspapers to teach economic principles are suggested classroom activities for elementary and secondary courses. A lesson plan for teaching democratic values is also included. (JR)

  7. Culture in the Classroom

    Science.gov (United States)

    Medin, Douglas L.; Bang, Megan

    2014-01-01

    Culture plays a large but often unnoticeable role in what we teach and how we teach children. We are a country of immense diversity, but in classrooms the dominant European-American culture has become the language of learning.

  8. Boardgames in the Classroom.

    Science.gov (United States)

    Boucher, Robert F.

    1979-01-01

    The article describes the program at Wellesley (Massachusetts) High School's Academic Resource Center, a program in which game-playing is used to improve the academic functioning of special needs students in preparation for reintegration into the regular classroom. (SBH)

  9. The Classroom Animal: Mealworms.

    Science.gov (United States)

    Kramer, David C., Ed.

    1985-01-01

    Describes appearance, longevity, and changes in each step of the mealworm life cycle. Guidelines for starting a classroom colony are given with housing and care instructions. Suggested observations, activities, and questions for students are included. (DH)

  10. The Classroom Animal.

    Science.gov (United States)

    Kramer, David C., Ed.

    1985-01-01

    Discusses the behavior, housing, care, diet, and feeding of painted turtles. Also suggests several classroom activities and provides guidelines related to long-term captivity and human disease prevention. (DH)

  11. DISCIPLINE OR CLASSROOM MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Bulent Tarman

    2016-07-01

    Full Text Available The purposes of this literature review are twofold. Firstly, it explains discipline and causes of students’ misbehavior and classroom management. In this sense, this review focuses on discipline in the conflict of the educational platform elements; and related the philosophic literature. Secondly, this review draws a conclusion by summarizing the opinions and influencing of discipline upon school environment and students’ learning. In this regard, this study discusses two models for dealing with classroom discipline: psychoanalytic method and behavior modification. Although two models apply different methods for dealing with classroom discipline, this study suggests that, to create a successful classroom management, educators should use both of them instead of applying only the one.

  12. Critters in the Classroom.

    Science.gov (United States)

    Smith, Robert W.; Fleisher, Paul

    1984-01-01

    The use of invertebrates as classroom "pets" can develop students' skills in scientific inquiry and instill respect for science. Few materials are needed for projects involving invertebrates. Suggested activities using snails, crickets, earthworms, crayfish, and guppies are offered. (DF)

  13. Modifying Classroom Behavior

    Science.gov (United States)

    Heifetz, Louis J.; Farber, Barry A.

    1976-01-01

    An introductory framework for analyzing and modifying classroom behavior...is followed by presentation of illustrative case materials, discussion of philosophical and ethical issues, analysis of pitfalls to be avoided, and consideration of limitations inherent in behavioral approaches. (Author)

  14. Image-based metal artifact reduction in x-ray computed tomography utilizing local anatomical similarity

    Science.gov (United States)

    Dong, Xue; Yang, Xiaofeng; Rosenfield, Jonathan; Elder, Eric; Dhabaan, Anees

    2017-03-01

    X-ray computed tomography (CT) is widely used in radiation therapy treatment planning in recent years. However, metal implants such as dental fillings and hip prostheses can cause severe bright and dark streaking artifacts in reconstructed CT images. These artifacts decrease image contrast and degrade HU accuracy, leading to inaccuracies in target delineation and dose calculation. In this work, a metal artifact reduction method is proposed based on the intrinsic anatomical similarity between neighboring CT slices. Neighboring CT slices from the same patient exhibit similar anatomical features. Exploiting this anatomical similarity, a gamma map is calculated as a weighted summation of relative HU error and distance error for each pixel in an artifact-corrupted CT image relative to a neighboring, artifactfree image. The minimum value in the gamma map for each pixel is used to identify an appropriate pixel from the artifact-free CT slice to replace the corresponding artifact-corrupted pixel. With the proposed method, the mean CT HU error was reduced from 360 HU and 460 HU to 24 HU and 34 HU on head and pelvis CT images, respectively. Dose calculation accuracy also improved, as the dose difference was reduced from greater than 20% to less than 4%. Using 3%/3mm criteria, the gamma analysis failure rate was reduced from 23.25% to 0.02%. An image-based metal artifact reduction method is proposed that replaces corrupted image pixels with pixels from neighboring CT slices free of metal artifacts. This method is shown to be capable of suppressing streaking artifacts, thereby improving HU and dose calculation accuracy.

  15. Characterization of Aortic Valve Closure Artifact During Outflow Tract Mapping: Correlation With Hemodynamics and Mechanical Valves.

    Science.gov (United States)

    Romero, Jorge; Ajijola, Olujimi; Shivkumar, Kalyanam; Tung, Roderick

    2017-06-01

    Premature ventricular contractions originating in the left ventricle outflow tract represent a significant subgroup of patients referred for catheter ablation. Mechanical artifacts from aortic valve leaflet motion may be observed during mapping, although the incidence and characteristics have not been reported. Twenty-eight consecutive patients with left ventricle outflow tract premature ventricular contraction were included. Electric signals recorded on the ablation catheter not coincident with atrial or ventricular depolarization were analyzed on the recording system. Correlation with invasive hemodynamic aortic pressure tracings was performed. Additionally, 4 patients with mechanical aortic valves, who underwent scar-related ventricular tachycardia ablation, were analyzed to correlate the timing of the observed artifacts with native aortic valves. Aortic valve artifact was observed while mapping within the coronary cusps in 11 patients (39%; 73% men; age, 41±25 years; left ventricular ejection fraction 49±16%) with high incidence from the left coronary cusp. This artifact was consistently observed with timing coincident with the terminal portion of the T wave. The average interval between the end of the T wave and the aortic valve artifact was 19±37 ms. The duration of the aortic valve artifact was 39±8 ms with amplitude of 0.12±0.07 mV (range, 0.06-0.36 mV). In patients referred for left ventricle outflow tract premature ventricular contraction ablation, an aortic valve closure artifact is observed in up to one third of cases during mapping within the aortic cusps. The timing of this artifact correlates with invasive hemodynamics and mechanical aortic valve artifacts. Recognition of this physiological phenomenon is useful when assigning near-field activation. © 2017 American Heart Association, Inc.

  16. Bridging Classroom Language Ethnography

    OpenAIRE

    Grenfell, Michael James

    2012-01-01

    PUBLISHED Paper #5: Bridging Classroom Language Ethnography, New Literacy Studies and Bourdieu?s Social Philosophy: Principles and Practice The purpose of this paper is to analyze and synthesize the various ways that classroom language ethnography, NLS, and Bourdieu?s social philosophy, were integrated. The goal of the analysis and synthesis is to provide a fresh perspective and fruitful insights on literacy in all its manifestations that provides the foundations for a more robust...

  17. Flipped Classroom Approach

    OpenAIRE

    Fezile Ozdamli; Gulsum Asiksoy

    2016-01-01

    Flipped classroom is an active, student-centered approach that was formed to increase the quality of period within class. Generally this approach whose applications are done mostly in Physical Sciences, also attracts the attention of educators and researchers in different disciplines recently. Flipped classroom learning which wide-spreads rapidly in the world, is not well recognized in our country. That is why the aim of study is to attract attention to its potential in education field and pr...

  18. Classroom Management Information Technology

    OpenAIRE

    Haq, Mohammad Syahidul

    2017-01-01

    Development of Information Technology in the field of education today can not be avoided. In the learning process is now not limited to space and time with the presence of information technology. To realize quality of learning, information technology is one aspect of classroom management. Many strategies are offered in classroom management To realize learning objectives. E-learning is a solution in the management of information technology-based classes are much used in various educational ins...

  19. Analyzing pictorial artifacts from psychotherapy and art therapy when overcoming stress and trauma

    DEFF Research Database (Denmark)

    Gerge, Anna; Pedersen, Inge Nygaard

    2017-01-01

    to look for in pictorial artifacts related overcome traumatization and dissociation. After an introduction to psychotraumatology and it’s adaptions to creative arts therapy and art therapy, a literature review on assessment tools in art therapy, which can be applicable for measuring overcome...... traumatization, will be addressed. The need of a multi-dimensional tool for analysis of pictorial artifacts done in therapy is asked for and the needed components are briefly sketched. Finally the value of pictorial artifacts, made by clients in psycho-social interventions, as valid “windows” of implicit change...

  20. Eliminating Dewar Narcissus artifacts induced by moving optics in infrared staring focal plane sensors

    Science.gov (United States)

    McCulloch, Philip M.; Olson, Craig; Goodman, Timothy D.

    2012-10-01

    Staring infrared imagers have multiple surfaces within the integrated Dewar assembly which contribute to non-traditional Narcissus artifacts. Static non-uniformity correction is insufficient to remove dynamic Narcissus artifacts caused by moving focus or zoom groups. Dynamic Narcissus artifacts often manifest as rings apparent to the human eye, although they may lie near the noise floor of the imager. Moreover, strong field curvature of the Narcissus can complicate diagnosis using paraxial methods. We compare a simple pupil ghost metric to traditional Narcissus metrics and present an experimental case study illustrating how the metric can be used during optimization to eliminate the effect.

  1. Color dissociation artifacts in double Maddox rod cyclodeviation testing.

    Science.gov (United States)

    Simons, K; Arnoldi, K; Brown, M H

    1994-12-01

    The double Maddox rod test, based on a red Maddox rod in front of one eye and a clear Maddox rod in front of the other, is used to measure cyclodeviation, typically in patients with superior oblique muscle pareses. Discrepant results between the double Maddox rod test and other torsion measures, and reports of "paradoxic" cyclodeviation in the normal eye of some patients with superior oblique paresis, suggest the two-color format of the double Maddox rod test may produce artifactual torsion measures. Forty patients with superior oblique paresis were tested twice using the double Maddox rod test, reversing the red and white Maddox rods between eyes for the second test, and 18 were tested further with same-color red or clear Maddox rods in front of both eyes. With the standard double Maddox rod test, 33 (83%) of 40 patients localized their cyclodeviation to the eye viewing through the red Maddox rod, irrespective of laterality of the paresis or fixation preference. In all 33 patients, laterality of the perceived torsion changed between eyes when testing was repeated with red and white Maddox rods interchanged between eyes. With same-color Maddox rods before both eyes, 17 (94%) of 18 patients localized extorsion to the paretic eye. There was 7.6:1 ratio of luminance transmission and a 1.6:1 ratio of grating spatial frequency bandpass in the plano meridian between the clear and red Maddox rods, which appear to be responsible for the double Maddox rod test artifact. The traditional double Maddox rod test may produce artifactual cyclodeviation measurements. An alternative version of the test, based on same-color Maddox rods in front of both eyes, is proposed. The relatively high spatial frequency bandpass characteristics of the plano meridian of the Maddox rod (as high as 20/25 Snellen equivalent resolution through the clear Maddox rod) also suggests double Maddox rod testing should be conducted in a dark room to avoid biases from visual environment cues.

  2. SU-F-J-74: High Z Geometric Integrity and Beam Hardening Artifact Assessment Using a Retrospective Metal Artifact Reduction (MAR) Reconstruction Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Woods, K; DiCostanzo, D; Gupta, N [Ohio State University Columbus, OH (United States)

    2016-06-15

    Purpose: To test the efficacy of a retrospective metal artifact reduction (MAR) reconstruction algorithm for a commercial computed tomography (CT) scanner for radiation therapy purposes. Methods: High Z geometric integrity and artifact reduction analysis was performed with three phantoms using General Electric’s (GE) Discovery CT. The three phantoms included: a Computerized Imaging Reference Systems (CIRS) electron density phantom (Model 062) with a 6.5 mm diameter titanium rod insert, a custom spine phantom using Synthes Spine hardware submerged in water, and a dental phantom with various high Z fillings submerged in water. Each phantom was reconstructed using MAR and compared against the original scan. Furthermore, each scenario was tested using standard and extended Hounsfield Unit (HU) ranges. High Z geometric integrity was performed using the CIRS phantom, while the artifact reduction was performed using all three phantoms. Results: Geometric integrity of the 6.5 mm diameter rod was slightly overestimated for non-MAR scans for both standard and extended HU. With MAR reconstruction, the rod was underestimated for both standard and extended HU. For artifact reduction, the mean and standard deviation was compared in a volume of interest (VOI) in the surrounding material (water and water equivalent material, ∼0HU). Overall, the mean value of the VOI was closer to 0 HU for the MAR reconstruction compared to the non-MAR scan for most phantoms. Additionally, the standard deviations for all phantoms were greatly reduced using MAR reconstruction. Conclusion: GE’s MAR reconstruction algorithm improves image quality with the presence of high Z material with minimal degradation of its geometric integrity. High Z delineation can be carried out with proper contouring techniques. The effects of beam hardening artifacts are greatly reduced with MAR reconstruction. Tissue corrections due to these artifacts can be eliminated for simple high Z geometries and greatly

  3. The Destructive/Non-Destructive Identification of Enameled Pottery, Glass Artifacts and Associated Pigments—A Brief Overview

    Directory of Open Access Journals (Sweden)

    Philippe Colomban

    2013-07-01

    Full Text Available The birth of Chemistry can be found in two main practices: (i the Arts du feu (ceramic and glass, metallurgy, i.e., inorganic and solid state chemistry and (ii the preparation of remedies, alcohols and perfumes, dyes, i.e., organic and liquid state chemistry. After a brief survey of the history of (glazed pottery and (enameled glass artifacts, the development of destructive and non-destructive analytical techniques during the last few centuries is reviewed. Emphasis is put on mobile non-destructive Raman microspectroscopy of pigments and their glass/glaze host matrices for chronological/technological expertise. The techniques of white opacification, blue, yellow, green, red, and black coloring, are used as examples to point out the interest of pigments as chronological/technological markers.

  4. Archaeology Through Computational Linguistics: Inscription Statistics Predict Excavation Sites of Indus Valley Artifacts.

    Science.gov (United States)

    Recchia, Gabriel L; Louwerse, Max M

    2016-11-01

    Computational techniques comparing co-occurrences of city names in texts allow the relative longitudes and latitudes of cities to be estimated algorithmically. However, these techniques have not been applied to estimate the provenance of artifacts with unknown origins. Here, we estimate the geographic origin of artifacts from the Indus Valley Civilization, applying methods commonly used in cognitive science to the Indus script. We show that these methods can accurately predict the relative locations of archeological sites on the basis of artifacts of known provenance, and we further apply these techniques to determine the most probable excavation sites of four sealings of unknown provenance. These findings suggest that inscription statistics reflect historical interactions among locations in the Indus Valley region, and they illustrate how computational methods can help localize inscribed archeological artifacts of unknown origin. The success of this method offers opportunities for the cognitive sciences in general and for computational anthropology specifically. Copyright © 2015 Cognitive Science Society, Inc.

  5. Metal artifact reduction by projection replacements and non-local prior image integration

    Directory of Open Access Journals (Sweden)

    Stille Maik

    2015-09-01

    Full Text Available The presence of high-density objects remains an open problem in medical CT imaging. Data of projections that passing through such objects are dominated by noise. Reconstructed images become less diagnostically conclusive because of pronounced artifacts that manifest as dark and bright streaks. A new reconstruction algorithm is proposed, which incorporates information gained from a prior image. Based on a non-local regularization, these information are used to reduce streaking artifacts. In an iterative scheme, the prior image is transformed in order to match intermediate results of the reconstruction by solving a registration problem. During iterations, temporally appearing artifacts are reduced with a bilateral filter and projection values passing through high-density objects are replaced by new calculated values, which are used further on for the reconstruction. Results show that the proposed algorithm significantly reduces streaking artifacts.

  6. A program to compute geographical positions of underwater artifact based on linear measurements

    Digital Repository Service at National Institute of Oceanography (India)

    Ganesan, P.

    While carrying out underwater positioning in shallow waters, the Diver Archaeologists measure lengths and bearings from a base line of the well-established control network to each and every corner of the artifact. A program in Basic language...

  7. $\\mu$-tempered metadynamics: Artifact independent convergence times for wide hills

    CERN Document Server

    Dickson, Bradley M

    2015-01-01

    Recent analysis of well-tempered metadynamics (WTmetaD) showed that it converges without mollification artifacts in the bias potential. Here we explore how metadynamics heals mollification artifacts, how healing impacts convergence time, and whether alternative temperings may be used to improve efficiency. We introduce "$\\mu$-tempered" metadynamics as a simple tempering scheme, inspired by a related mollified adaptive biasing potential (mABP), that results in artifact independent convergence of the free energy estimate. We use a toy model to examine the role of artifacts in WTmetaD and solvated alanine dipeptide to compare the well-tempered and $\\mu$-tempered frameworks demonstrating fast convergence for hill widths as large as $60^{\\circ}$ for $\\mu$TmetaD.

  8. Are Movement Artifacts in Magnetic Resonance Imaging a Real Problem?—A Narrative Review

    Directory of Open Access Journals (Sweden)

    Inger Havsteen

    2017-05-01

    Full Text Available Movement artifacts compromise image quality and may interfere with interpretation, especially in magnetic resonance imaging (MRI applications with low signal-to-noise ratio such as functional MRI or diffusion tensor imaging, and when imaging small lesions. High image resolution has high sensitivity to motion artifacts and often prolongs scan time that again aggravates movement artifacts. During the scan fast imaging techniques and sequences, optimal receiver coils, careful patient positioning, and instruction may minimize movement artifacts. Physiological noise sources are motion from respiration, flow and pulse coupled to cardiac cycles, from the swallowing reflex and small spontaneous head movements. Par example, in resting-state functional MRI spontaneous neuronal activity adds 1–2% of signal change, even under optimal conditions signal contributions from physiological noise remain a considerable fraction hereof. Movement tracking during imaging may allow for prospective correction or postprocessing steps separating signal and noise.

  9. Ultrasound artifacts as differential diagnostic problems in ultrasound of the upper abdomen

    National Research Council Canada - National Science Library

    Hadnadev, Dusan; Stojanović, Sanja; Govorcin, Mira; Vucaj, Viktorija; Nićiforović, Dijana; Kozić, Dusan

    2005-01-01

    .... Recognition of artifacts in everyday work is of great significance for final diagnosis, since their wrong interpretation not only compromises the value of ultrasound finding, but may also lead...

  10. Do Martian Blueberries Have Pits? -- Artifacts of an Early Wet Mars

    Science.gov (United States)

    Lerman, L.

    2005-03-01

    Early Martian weather cycles would have supported organic chemical self-organization, the assumed predecessor to an independent "origin" of Martian life. Artifacts of these processes are discussed, including the possibility that Martian blueberries nucleated around organic cores.

  11. Mitigation of Selected Hanford Site Manhattan Project and Cold War Era Artifacts

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Ellen P.; Harvey, David W.

    2006-09-08

    This document is the first time that Manhattan Project and Cold War era artifacts from the Hanford Site have been assembled within a publication. The publication presents photographic and written documentation of a number of Manhattan Project and Cold War era artifacts that were identified and tagged during assessment walk throughs of historic buildings on the Hanford Site but which could not be curated within the Hanford collection because they were too large for long-term storage and/or exhibit purposes or were radiologically contaminated. The significance of the artifacts in this publication and a proposed future appendix is based not on the individual significance of any single artifact but on their collective contribution to the science and engineering of creating plutonium and advancing nuclear technology in nuclear fuel and power.

  12. Reducing motion artifacts in photoplethysmograms by using relative sensor motion: phantom study

    NARCIS (Netherlands)

    Wijshoff, R.W.C.G.R.; Mischi, M.; Veen, J.; Van der Lee, A.M.; Aarts, R.M.

    2012-01-01

    Currently, photoplethysmograms (PPGs) are mostly used to determine apatient's blood oxygenation and pulse rate. However, PPG morphologyconveys more information about the patient's cardiovascular status.Extracting this information requires measuring clean PPG waveformsthat are free of artifacts. PPGs

  13. Artifacts found during quality assurance testing of computed radiography and digital radiography detectors

    National Research Council Canada - National Science Library

    Honey, Ian D; Mackenzie, Alistair

    2009-01-01

    ...) and integrated digital radiographic X-ray imaging detectors are presented. The images presented are all either flat field or test object images and show artifacts previously either undescribed in the existing literature or meriting further comment...

  14. Cell Phones in the Classroom: Teachers' Perspectives of Inclusion, Benefits, and Barriers

    Science.gov (United States)

    Thomas, Kevin M.; O'Bannon, Blanche W.; Bolton, Natalie

    2013-01-01

    Historically viewed as a disruption by teachers, cell phones have been banned from 69% of classrooms (Common Sense Media, 2009). The increased ubiquity and instructional features of cell phones have prompted some teachers to re-evaluate the ban and consider the benefits associated with allowing cell phones in the classroom. This study surveyed 79…

  15. Using Energy Psychology in Classrooms to Decrease Tension in College Students

    Science.gov (United States)

    Wolf, Jillian

    2012-01-01

    This research explores the impact of student use of energy psychology techniques in the classroom setting. The descriptive design quasi-experimental study also examines how energy psychology techniques used in the classroom are related to age and gender by use of the survey method. Questionnaire packets were administered to seventy-five college…

  16. A Study of Pre-Service Classroom Teachers' Beliefs about Teachers' and Students' Roles

    Science.gov (United States)

    Kögce, Davut

    2017-01-01

    The aim of this study is to determine pre-service classroom teachers' beliefs and thoughts about the roles of teachers and students in the classroom before taking the Mathematics Teaching I course. With this purpose, the study employed the survey method, a descriptive research technique. The study sample included 75 pre-service teachers (55…

  17. Examining the Knowledge and Capacity of Elementary Teachers to Implement Classroom Physical Activity Breaks

    Science.gov (United States)

    Dinkel, Danae M.; Lee, Jung-Min; Schaffer, Connie

    2016-01-01

    This study examined teachers' zone of proximal development for classroom physical activity breaks by assessing teachers' knowledge and capacity for implementing classroom physical activity breaks. Five school districts of various sizes (n = 346 teachers) took part in a short online survey. Descriptive statistics were calculated and chi-square…

  18. Pre-Service Secondary Science and Mathematics Teachers' Classroom Management Styles in Turkey

    Science.gov (United States)

    Yilmaz, Kursad

    2009-01-01

    The aim of this study is to determine Pre-service secondary science and mathematics teachers' classroom management styles in Turkey. In addition, differences in pre-service secondary science and mathematics teachers' classroom management styles by gender, and field of study were examined. In the study, the survey model was employed. The research…

  19. Teachers' Reported Knowledge and Implementation of Research-Based Classroom and Behavior Management Strategies

    Science.gov (United States)

    Moore, Tara C.; Wehby, Joseph H.; Oliver, Regina M.; Chow, Jason C.; Gordon, Jason R.; Mahany, Laura A.

    2017-01-01

    Teachers' reported knowledge about and implementation of research-based classroom and behavior management strategies were examined. A total of 160 elementary teachers from two districts in different regions of the same state completed the researcher-developed "Survey of Classroom and Behavior Management." On average, teachers reported to…

  20. Do Prospective Classroom Teachers Perceive Themselves as Effective and Willing to Teach Young Learners English?

    Science.gov (United States)

    Sad, Süleyman Nihat

    2015-01-01

    This study aimed to investigate the perceived efficacy and willingness levels of prospective classroom teachers to teach English at the primary level. The study was designed as a baseline descriptive survey, followed by complementary correlational and ex post facto models. Participants were 251 prospective classroom teachers. Data was collected…

  1. Quality-Improving Strategies of College English Teaching Based on Microlesson and Flipped Classroom

    Science.gov (United States)

    Zhang, Fan

    2017-01-01

    Microlesson and flipped classroom, which incorporate the educational information technologies, are a new trend of college English teaching. Exploration on how the flipped classroom and microlesson promote innovation and application of educational information technology are of great significance. According to a survey among teachers, strategies…

  2. Sense of Classroom Community and Team Development Process in Online Learning

    Science.gov (United States)

    Erdem Aydin, Irem; Gumus, Salih

    2016-01-01

    The purpose of this study is to determine whether there is a relationship between Turkish online learners' sense of classroom community, perceptions of success in team development process and their preferences of studying in teams. A survey instrument included the Sense of Classroom Community Scale, Tuckman's Teamwork Questionnaire and some other…

  3. A robust adaptive denoising framework for real-time artifact removal in scalp EEG measurements

    Science.gov (United States)

    Kilicarslan, Atilla; Grossman, Robert G.; Contreras-Vidal, Jose Luis

    2016-04-01

    Objective. Non-invasive measurement of human neural activity based on the scalp electroencephalogram (EEG) allows for the development of biomedical devices that interface with the nervous system for scientific, diagnostic, therapeutic, or restorative purposes. However, EEG recordings are often considered as prone to physiological and non-physiological artifacts of different types and frequency characteristics. Among them, ocular artifacts and signal drifts represent major sources of EEG contamination, particularly in real-time closed-loop brain-machine interface (BMI) applications, which require effective handling of these artifacts across sessions and in natural settings. Approach. We extend the usage of a robust adaptive noise cancelling (ANC) scheme ({H}∞ filtering) for removal of eye blinks, eye motions, amplitude drifts and recording biases simultaneously. We also characterize the volume conduction, by estimating the signal propagation levels across all EEG scalp recording areas due to ocular artifact generators. We find that the amplitude and spatial distribution of ocular artifacts vary greatly depending on the electrode location. Therefore, fixed filtering parameters for all recording areas would naturally hinder the true overall performance of an ANC scheme for artifact removal. We treat each electrode as a separate sub-system to be filtered, and without the loss of generality, they are assumed to be uncorrelated and uncoupled. Main results. Our results show over 95-99.9% correlation between the raw and processed signals at non-ocular artifact regions, and depending on the contamination profile, 40-70% correlation when ocular artifacts are dominant. We also compare our results with the offline independent component analysis and artifact subspace reconstruction methods, and show that some local quantities are handled better by our sample-adaptive real-time framework. Decoding performance is also compared with multi-day experimental data from 2 subjects

  4. Results of a Flipped Classroom Teaching Approach in Anesthesiology Residents.

    Science.gov (United States)

    Martinelli, Susan M; Chen, Fei; DiLorenzo, Amy N; Mayer, David C; Fairbanks, Stacy; Moran, Kenneth; Ku, Cindy; Mitchell, John D; Bowe, Edwin A; Royal, Kenneth D; Hendrickse, Adrian; VanDyke, Kenneth; Trawicki, Michael C; Rankin, Demicha; Guldan, George J; Hand, Will; Gallagher, Christopher; Jacob, Zvi; Zvara, David A; McEvoy, Matthew D; Schell, Randall M

    2017-08-01

    In a flipped classroom approach, learners view educational content prior to class and engage in active learning during didactic sessions. We hypothesized that a flipped classroom improves knowledge acquisition and retention for residents compared to traditional lecture, and that residents prefer this approach. We completed 2 iterations of a study in 2014 and 2015. Institutions were assigned to either flipped classroom or traditional lecture for 4 weekly sessions. The flipped classroom consisted of reviewing a 15-minute video, followed by 45-minute in-class interactive sessions with audience response questions, think-pair-share questions, and case discussions. The traditional lecture approach consisted of a 55-minute lecture given by faculty with 5 minutes for questions. Residents completed 3 knowledge tests (pretest, posttest, and 4-month retention) and surveys of their perceptions of the didactic sessions. A linear mixed model was used to compare the effect of both formats on knowledge acquisition and retention. Of 182 eligible postgraduate year 2 anesthesiology residents, 155 (85%) participated in the entire intervention, and 142 (78%) completed all tests. The flipped classroom approach improved knowledge retention after 4 months (adjusted mean = 6%; P  = .014; d  = 0.56), and residents preferred the flipped classroom (pre = 46%; post = 82%; P  flipped classroom approach to didactic education resulted in a small improvement in knowledge retention and was preferred by anesthesiology residents.

  5. Study and practice of flipped classroom in optoelectronic technology curriculum

    Science.gov (United States)

    Shi, Jianhua; Lei, Bing; Liu, Wei; Yao, Tianfu; Jiang, Wenjie

    2017-08-01

    "Flipped Classroom" is one of the most popular teaching models, and has been applied in more and more curriculums. It is totally different from the traditional teaching model. In the "Flipped Classroom" model, the students should watch the teaching video afterschool, and in the classroom only the discussion is proceeded to improve the students' comprehension. In this presentation, "Flipped Classroom" was studied and practiced in opto-electronic technology curriculum; its effect was analyzed by comparing it with the traditional teaching model. Based on extensive and deep investigation, the phylogeny, the characters and the important processes of "Flipped Classroom" are studied. The differences between the "Flipped Classroom" and the traditional teaching model are demonstrated. Then "Flipped Classroom" was practiced in opto-electronic technology curriculum. In order to obtain high effectiveness, a lot of teaching resources were prepared, such as the high-quality teaching video, the animations and the virtual experiments, the questions that the students should finish before and discussed in the class, etc. At last, the teaching effect was evaluated through analyzing the result of the examination and the students' surveys.

  6. TU-F-CAMPUS-J-04: Evaluation of Metal Artifact Reduction Technique for the Radiation Therapy Planning

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, K; Kuo, H; Ritter, J; Shen, J; Basavatia, A; Yaparpalvi, R; Kalnicki, S [Montefiore Medical Center, Bronx, NY (United States); Tome, W [Montefiore Medical Center, ALBERT EINSTEIN COLLEGE OF MEDICINE, Bronx, NY (United States)

    2015-06-15

    Purpose: To evaluate the feasibility of using a metal artifact reduction technique in depleting metal artifact and its application in improving dose calculation in External Radiation Therapy Planning. Methods: CIRS electron density phantom was scanned with and without steel drill bits placed in some plug holes. Meta artifact reduction software with Metal Deletion Technique (MDT) was used to remove metal artifacts for scanned image with metal. Hounsfield units of electron density plugs from artifact free reference image and MDT processed images were compared. To test the dose calculation improvement after the MDT processed images, clinically approved head and neck plan with manual dental artifact correction was tested. Patient images were exported and processed with MDT and plan was recalculated with new MDT image without manual correction. Dose profiles near the metal artifacts were compared. Results: The MDT used in this study effectively reduced the metal artifact caused by beam hardening and scatter. The windmill around the metal drill was greatly improved with smooth rounded view. Difference of the mean HU in each density plug between reference and MDT images were less than 10 HU in most of the plugs. Dose difference between original plan and MDT images were minimal. Conclusion: Most metal artifact reduction methods were developed for diagnostic improvement purpose. Hence Hounsfield unit accuracy was not rigorously tested before. In our test, MDT effectively eliminated metal artifacts with good HU reproduciblity. However, it can introduce new mild artifacts so the MDT images should be checked with original images.

  7. Evaluation of digital tomosynthesis reconstruction algorithms used to reduce metal artifacts for arthroplasty: A phantom study.

    Science.gov (United States)

    Gomi, Tsutomu; Sakai, Rina; Goto, Masami; Hara, Hidetake; Watanabe, Yusuke; Umeda, Tokuo

    2017-10-01

    To investigate methods to reduce metal artifacts during digital tomosynthesis for arthroplasty, we evaluated five algorithms with and without metal artifact reduction (MAR)-processing tested under different radiation doses (0.54, 0.47, and 0.33mSv): adaptive steepest descent projection onto convex sets (ASD-POCS), simultaneous algebraic reconstruction technique total variation (SART-TV), filtered back projection (FBP), maximum likelihood expectation maximization (MLEM), and SART. The algorithms were assessed by determining the artifact index (AI) and artifact spread function (ASF) on a prosthesis phantom. The AI data were statistically analyzed by two-way analysis of variance. Without MAR-processing, the greatest degree of effectiveness of the MLEM algorithm for reducing prosthetic phantom-related metal artifacts was achieved by quantification using the AI (MLEM vs. ASD-POCS, SART-TV, SART, and FBP; all PTV, and SART algorithms for reducing prosthetic phantom-related metal artifacts was achieved by quantification using the AI (MLEM, ASD-POCS, SART-TV, and SART vs. FBP; all PTV, and SART algorithm with MAR-processing. In ASF, the effect of metal artifact reduction was always greater at reduced radiation doses, regardless of which reconstruction algorithm with and without MAR-processing was used. In this phantom study, the MLEM algorithm without MAR-processing and ASD-POCS, SART-TV, and SART algorithm with MAR-processing gave improved metal artifact reduction. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  8. Evaluation of Metallic Artifacts Caused by Nonpenetrating Titanium Clips in Postoperative Neuroimaging.

    Science.gov (United States)

    Ito, Kiyoshi; Seguchi, Tatsuya; Nakamura, Takuya; Chiba, Akihiro; Hasegawa, Takatoshi; Nagm, Alhusain; Horiuchi, Tetsuyoshi; Hongo, Kazuhiro

    2016-12-01

    Nonpenetrating titanium clips create no suture holes and thereby reduce cerebrospinal fluid leakage after dural closure. However, no data exist regarding metallic artifacts caused by these clips during postoperative neuroimaging. We aimed to evaluate clip-related artifacts on postoperative magnetic resonance (MR) images of 17 patients who underwent spinal surgery. A phantom study evaluated the size of metallic artifacts, and a clinical study evaluated the quality of postoperative spinal MR images. Both 1.5-T studies used T1-weighted and T2-weighted fast spin echo sequences. The phantom study compared clip and artifact size for 10 clips. Artifacts were defined as signal voids surrounded by high signal amplitude that followed the clip shape. In the clinical study, 2 neurosurgeons assessed 22 images from 17 patients of the spinal cord, cauda equina, and paravertebral muscles adjacent to the nonpenetrating titanium clips, using 5-point scales. Mean metallic artifact sizes were 4.82 ± 0.16 mm (T1) and 4.66 ± 0.25 mm (T2; P < 0.001 vs. control). The former and latter were respectively 207% and 200% larger than the clip size. Both readers graded spinal cord and paravertebral muscles images as 3 or 4, indicating very good image quality regardless of clip-related artifacts, with excellent interobserver agreement (κ = 0.99 and 0.98, respectively). Metallic artifacts caused by nonpenetrating titanium clips were 200% larger than the actual clip but did not affect spinal cord and extradural tissue visualization. The use of these clips for closing the spinal dura mater does not alter postoperative radiologic evaluation quality. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Ultrasound-guided probe-generated artifacts stimulating ventricular tachycardia: A rare phenomenon

    Directory of Open Access Journals (Sweden)

    Rafat Shamim

    2017-01-01

    Full Text Available Electrocardiographic (ECG artifacts may arise due to interference, faulty earthing, and current leakages in biomedical equipment which might create clinical dilemmas in the perioperative settings. Piezoelectric signals generated by ultrasonography probe are another uncommon source which might be sensed by the ECG electrodes and produce tracings similar to pathological arrhythmias triggering false alarms and avoidable therapies. Anesthesiologists should be familiar with these uncommon sources which might produce these artifacts and they should be identified swiftly.

  10. EOG Artifact Correction from EEG Recording Using Stationary Subspace Analysis and Empirical Mode Decomposition

    OpenAIRE

    Hongyun Qin; Ruqiang Yan; Aiguo Song; Hong Zeng

    2013-01-01

    Ocular contamination of EEG data is an important and very common problem in the diagnosis of neurobiological events. An effective approach is proposed in this paper to remove ocular artifacts from the raw EEG recording. First, it conducts the blind source separation on the raw EEG recording by the stationary subspace analysis, which can concentrate artifacts in fewer components than the representative blind source separation methods. Next, to recover the neural information that has leaked int...

  11. Speeding up image quality improvement in random phase-free holograms using ringing artifact characteristics.

    Science.gov (United States)

    Nagahama, Yuki; Shimobaba, Tomoyoshi; Kakue, Takashi; Masuda, Nobuyuki; Ito, Tomoyoshi

    2017-05-01

    A holographic projector utilizes holography techniques. However, there are several barriers to realizing holographic projections. One is deterioration of hologram image quality caused by speckle noise and ringing artifacts. The combination of the random phase-free method and the Gerchberg-Saxton (GS) algorithm has improved the image quality of holograms. However, the GS algorithm requires significant computation time. We propose faster methods for image quality improvement of random phase-free holograms using the characteristics of ringing artifacts.

  12. Computer Science Approach to Information-Like Artifacts as Exemplified by Memes

    OpenAIRE

    Sabah Al-Fedaghi

    2015-01-01

    Providing information can be expanded to include systems that deliver information-like artifacts. They provide such “things” as advertisements, propaganda pieces, and meme artifacts. Memes are the subject of extensive intellectual debate in science and popular culture because it is claimed that parallels can be drawn between theories of cultural evolution manifested in memes, and theories of biological evolution. Memes are described as self-reproducing mental structures, intangible entities t...

  13. Reduction of variable-truncation artifacts from beam occlusion during in situ x-ray tomography

    Science.gov (United States)

    Borg, Leise; Jørgensen, Jakob S.; Frikel, Jürgen; Sporring, Jon

    2017-12-01

    Many in situ x-ray tomography studies require experimental rigs which may partially occlude the beam and cause parts of the projection data to be missing. In a study of fluid flow in porous chalk using a percolation cell with four metal bars drastic streak artifacts arise in the filtered backprojection (FBP) reconstruction at certain orientations. Projections with non-trivial variable truncation caused by the metal bars are the source of these variable-truncation artifacts. To understand the artifacts a mathematical model of variable-truncation data as a function of metal bar radius and distance to sample is derived and verified numerically and with experimental data. The model accurately describes the arising variable-truncation artifacts across simulated variations of the experimental setup. Three variable-truncation artifact-reduction methods are proposed, all aimed at addressing sinogram discontinuities that are shown to be the source of the streaks. The ‘reduction to limited angle’ (RLA) method simply keeps only non-truncated projections; the ‘detector-directed smoothing’ (DDS) method smooths the discontinuities; while the ‘reflexive boundary condition’ (RBC) method enforces a zero derivative at the discontinuities. Experimental results using both simulated and real data show that the proposed methods effectively reduce variable-truncation artifacts. The RBC method is found to provide the best artifact reduction and preservation of image features using both visual and quantitative assessment. The analysis and artifact-reduction methods are designed in context of FBP reconstruction motivated by computational efficiency practical for large, real synchrotron data. While a specific variable-truncation case is considered, the proposed methods can be applied to general data cut-offs arising in different in situ x-ray tomography experiments.

  14. 3D measurement for archeological artifact using CCD camera and line laser beam

    Science.gov (United States)

    Yokoyama, Hiroshi; Hatano, Katsuhiro; Chikatsu, Hirofumi

    1997-07-01

    In the compilation of archival records for archeological artifacts, true ortho-graphic drawings of these artifacts have to be drawn by the archaeologists themselves or part- timers, taking a great deal of time, labor and skill. For saving the labor, the authors have developed ortho projection system using CCD camera. 3D measurement system using ortho projection system are described in this paper. Finally, it demonstrates wireframe model for jomon-pottery by using this system.

  15. An Investigation of the Artifacts and Process of Constructing Computers Games about Environmental Science in a Fifth Grade Classroom

    Science.gov (United States)

    Baytak, Ahmet; Land, Susan M.

    2011-01-01

    This study employed a case study design (Yin, "Case study research, design and methods," 2009) to investigate the processes used by 5th graders to design and develop computer games within the context of their environmental science unit, using the theoretical framework of "constructionism." Ten fifth graders designed computer games using "Scratch"…

  16. Location of Artifacts Deposited by the Blow Fly Lucilia cuprina After Feeding on Human Blood at Simulated Indoor Crime Scenes.

    Science.gov (United States)

    Durdle, Annalisa; Verdon, Timothy J; Mitchell, Robert John; van Oorschot, Roland A H

    2017-11-16

    Human DNA profiles can be obtained from fly artifacts (feces and regurgitant) when a fly has been feeding on biological material, sometimes 2 years after deposition. Morphological similarity between artifacts and spots of unaltered biological material make it difficult to distinguish between them, and presumptive and confirmatory forensic tests are unreliable in making the distinction. Knowing possible artifact locations will assist investigators in recognizing where DNA contamination might occur. Flies were released into a house with human blood available under a variety of different climatic and lighting conditions. The location of flies and artifacts was recorded after 72 h. It was found flies may move toward warm or well-lit areas and deposit artifacts there, but artifacts were predominantly located around food sources and were often found in low positions. Factors such as ambient temperature, and the proximity of light and food sources, had an impact on where artifacts were deposited. © 2017 American Academy of Forensic Sciences.

  17. Automated EEG artifact elimination by applying machine learning algorithms to ICA-based features

    Science.gov (United States)

    Radüntz, Thea; Scouten, Jon; Hochmuth, Olaf; Meffert, Beate

    2017-08-01

    Objective. Biological and non-biological artifacts cause severe problems when dealing with electroencephalogram (EEG) recordings. Independent component analysis (ICA) is a widely used method for eliminating various artifacts from recordings. However, evaluating and classifying the calculated independent components (IC) as artifact or EEG is not fully automated at present. Approach. In this study, we propose a new approach for automated artifact elimination, which applies machine learning algorithms to ICA-based features. Main results. We compared the performance of our classifiers with the visual classification results given by experts. The best result with an accuracy rate of 95% was achieved using features obtained by range filtering of the topoplots and IC power spectra combined with an artificial neural network. Significance. Compared with the existing automated solutions, our proposed method is not limited to specific types of artifacts, electrode configurations, or number of EEG channels. The main advantages of the proposed method is that it provides an automatic, reliable, real-time capable, and practical tool, which avoids the need for the time-consuming manual selection of ICs during artifact removal.

  18. Deep learning methods for CT image-domain metal artifact reduction

    Science.gov (United States)

    Gjesteby, Lars; Yang, Qingsong; Xi, Yan; Shan, Hongming; Claus, Bernhard; Jin, Yannan; De Man, Bruno; Wang, Ge

    2017-09-01

    Artifacts resulting from metal objects have been a persistent problem in CT images over the last four decades. A common approach to overcome their effects is to replace corrupt projection data with values synthesized from an interpolation scheme or by reprojection of a prior image. State-of-the-art correction methods, such as the interpolation- and normalization-based algorithm NMAR, often do not produce clinically satisfactory results. Residual image artifacts remain in challenging cases and even new artifacts can be introduced by the interpolation scheme. Metal artifacts continue to be a major impediment, particularly in radiation and proton therapy planning as well as orthopedic imaging. A new solution to the long-standing metal artifact reduction (MAR) problem is deep learning, which has been successfully applied to medical image processing and analysis tasks. In this study, we combine a convolutional neural network (CNN) with the state-of-the-art NMAR algorithm to reduce metal streaks in critical image regions. Training data was synthesized from CT simulation scans of a phantom derived from real patient images. The CNN is able to map metal-corrupted images to artifact-free monoenergetic images to achieve additional correction on top of NMAR for improved image quality. Our results indicate that deep learning is a novel tool to address CT reconstruction challenges, and may enable more accurate tumor volume estimation for radiation therapy planning.

  19. Compton scattering artifacts in electron excited X-ray spectra measured with a silicon drift detector.

    Science.gov (United States)

    Ritchie, Nicholas W M; Newbury, Dale E; Lindstrom, Abigail P

    2011-12-01

    Artifacts are the nemesis of trace element analysis in electron-excited energy dispersive X-ray spectrometry. Peaks that result from nonideal behavior in the detector or sample can fool even an experienced microanalyst into believing that they have trace amounts of an element that is not present. Many artifacts, such as the Si escape peak, absorption edges, and coincidence peaks, can be traced to the detector. Others, such as secondary fluorescence peaks and scatter peaks, can be traced to the sample. We have identified a new sample-dependent artifact that we attribute to Compton scattering of energetic X-rays generated in a small feature and subsequently scattered from a low atomic number matrix. It seems likely that this artifact has not previously been reported because it only occurs under specific conditions and represents a relatively small signal. However, with the advent of silicon drift detectors and their utility for trace element analysis, we anticipate that more people will observe it and possibly misidentify it. Though small, the artifact is not inconsequential. Under some conditions, it is possible to mistakenly identify the Compton scatter artifact as approximately 1% of an element that is not present.

  20. Gaussian Elimination-Based Novel Canonical Correlation Analysis Method for EEG Motion Artifact Removal

    Directory of Open Access Journals (Sweden)

    Vandana Roy

    2017-01-01

    Full Text Available The motion generated at the capturing time of electro-encephalography (EEG signal leads to the artifacts, which may reduce the quality of obtained information. Existing artifact removal methods use canonical correlation analysis (CCA for removing artifacts along with ensemble empirical mode decomposition (EEMD and wavelet transform (WT. A new approach is proposed to further analyse and improve the filtering performance and reduce the filter computation time under highly noisy environment. This new approach of CCA is based on Gaussian elimination method which is used for calculating the correlation coefficients using backslash operation and is designed for EEG signal motion artifact removal. Gaussian elimination is used for solving linear equation to calculate Eigen values which reduces the computation cost of the CCA method. This novel proposed method is tested against currently available artifact removal techniques using EEMD-CCA and wavelet transform. The performance is tested on synthetic and real EEG signal data. The proposed artifact removal technique is evaluated using efficiency matrices such as del signal to noise ratio (DSNR, lambda (λ, root mean square error (RMSE, elapsed time, and ROC parameters. The results indicate suitablity of the proposed algorithm for use as a supplement to algorithms currently in use.

  1. Method for removing motion artifacts from fNIRS data using ICA and an acceleration sensor.

    Science.gov (United States)

    Hiroyasu, Tomoyuki; Nakamura, Yuka; Yokouchi, Hisatake

    2013-01-01

    Independent component analysis (ICA) is one of the most preferred methods for removing motion artifacts from functional near-infrared spectroscopy (fNIRS) data. In this method, fNIRS signal is separated into some components by ICA. The component which has high correlation between fNIRS signal and motion artifact is determined. This component is removed and fNIRS signal without motion artifact effect is derived. However, because of the influence of blood flow, fNIRS data are often delayed in time compared with the acceleration sensor data. Therefore, the correlation is reduced, and it is difficult to determine whether the component has been derived from the motion artifact. We here propose a method for removing the motion artifact using ICA, which considers the time delay in the fNIRS data. In this proposed method, ICA is performed multiple times, shifting the start time of the fNIRS data with each repeat. Then, only the best correlated result is adopted for comparison with the acceleration sensor data. To examine the effectiveness of this method, its results were compared with the results obtained without considering the time delay. It was found that the proposed method improved that accuracy of removing the motion artifact.

  2. An energy minimization method for the correction of cupping artifacts in cone-beam CT.

    Science.gov (United States)

    Xie, Shipeng; Zhuang, Wenqin; Li, Haibo

    2016-07-08

    The purpose of this study was to reduce cupping artifacts and improve quantitative accuracy of the images in cone-beam CT (CBCT). An energy minimization method (EMM) is proposed to reduce cupping artifacts in reconstructed image of the CBCT. The cupping artifacts are iteratively optimized by using efficient matrix computations, which are verified to be numerically stable by matrix analysis. Moreover, the energy in our formulation is convex in each of its variables, which brings the robustness of the proposed energy minimization algorithm. The cupping artifacts are estimated as a result of minimizing this energy. The results indicate that proposed algorithm is effective for reducing the cupping artifacts and preserving the quality of the reconstructed image. The proposed method focuses on the reconstructed image without requiring any additional physical equipment; it is easily implemented and provides cupping correction using a single scan acquisition. The experimental results demonstrate that this method can successfully reduce the magnitude of cupping artifacts. The correction algorithm reported here may improve the uniformity of the reconstructed images, thus assisting the development of perfect volume visualization and threshold-based visualization techniques for reconstructed images. © 2016 The Authors.

  3. An integrated blood pressure measurement system for suppression of motion artifacts.

    Science.gov (United States)

    Abderahman, Huthaifa N; Dajani, Hilmi R; Bolic, Miodrag; Groza, Voicu Z

    2017-07-01

    Accuracy in blood pressure (BP) estimation is essential for proper diagnosis and management of hypertension. Motion artifacts are considered external sources of inaccuracy and can be due to sudden arm motion, muscle tremor, shivering, and transport vehicle vibrations. In the proposed work, a new algorithmic stage is integrated in a non-invasive BP monitor. This stage suppresses the effect of the motion artifact and adjusts the pressure estimation before displaying it to users. The proposed stage is based on a 3-axis accelerometer signal, which helps in the accurate detection of the motion artifact. Both transient motion artifacts and artifact due to vibrations are suppressed using algorithms based on Empirical Mode Decomposition (EMD). Measurements with human subjects show that the proposed algorithms considerably improved the accuracy of the blood pressure estimates in comparison with the commonly-used conventional oscillometric algorithm that does not include an EMD-based stage for artifact suppression, and allowed the estimates to meet the requirements of the international ANSI/AAMI/ISO standard. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Metal artifact reduction using a patch-based reconstruction for digital breast tomosynthesis

    Science.gov (United States)

    Borges, Lucas R.; Bakic, Predrag R.; Maidment, Andrew D. A.; Vieira, Marcelo A. C.

    2017-03-01

    Digital breast tomosynthesis (DBT) is rapidly emerging as the main clinical tool for breast cancer screening. Although several reconstruction methods for DBT are described by the literature, one common issue is the interplane artifacts caused by out-of-focus features. For breasts containing highly attenuating features, such as surgical clips and large calcifications, the artifacts are even more apparent and can limit the detection and characterization of lesions by the radiologist. In this work, we propose a novel method of combining backprojected data into tomographic slices using a patch-based approach, commonly used in denoising. Preliminary tests were performed on a geometry phantom and on an anthropomorphic phantom containing metal inserts. The reconstructed images were compared to a commercial reconstruction solution. Qualitative assessment of the reconstructed images provides evidence that the proposed method reduces artifacts while maintaining low noise levels. Objective assessment supports the visual findings. The artifact spread function shows that the proposed method is capable of suppressing artifacts generated by highly attenuating features. The signal difference to noise ratio shows that the noise levels of the proposed and commercial methods are comparable, even though the commercial method applies post-processing filtering steps, which were not implemented on the proposed method. Thus, the proposed method can produce tomosynthesis reconstructions with reduced artifacts and low noise levels.

  5. Computed tomography of kidney with diuretics. A method for avoiding artifact due to nonionic contrast medium

    Energy Technology Data Exchange (ETDEWEB)

    Hiromura, Tadao; Terae, Satoshi; Takamura, Akio; Mizoe, Junetsu (Obihiro Kosei Hospital, Hokkaido (Japan)); Morita, Yutaka; Irie, Goro

    1989-07-01

    We devised a method for avoiding beam-hardening artifacts, which interfere with enhanced CT images of kidney due to nonionic contrast medium. The radiographic effect and the frequency of beam-hardening artifacts on enhanced CT of kidney were studied by prospective comparison among three groups: a group of 20 patients examined with furosemide (f-d.CT), a group of 20 patients examined without diuretics (non-d.CT) and a group of 20 patients examined after water intake (w-d.CT). In all patients of f-d.CT group, the renal parenchyma from the cortex to the papilla was almost evently enhanced, free from artifacts. The density of the renal papilla and pelvis in non-d.CT and w-d.CT groups was significantly higher than that in f-d.CT group, and artifacts were also observed in 14 (70%) of non-d.CT group and 12 (60%) of w.d.CT group, respectively. Satisfactory CT of kidney free from artifacts was obtained by f-d.CT, providing easy evaluation of renal pelvic or peripelvic lesions. In conclusion, this technique can be used in those pathologic cases of renal pelvis or peripelvic region, that are not clear on routine CT because of artifacts. (author).

  6. Reducing motion artifacts in photoplethysmograms by using relative sensor motion: phantom study

    Science.gov (United States)

    Wijshoff, Ralph W. C. G. R.; Mischi, Massimo; Veen, Jeroen; van der Lee, Alexander M.; Aarts, Ronald M.

    2012-11-01

    Currently, photoplethysmograms (PPGs) are mostly used to determine a patient's blood oxygenation and pulse rate. However, PPG morphology conveys more information about the patient's cardiovascular status. Extracting this information requires measuring clean PPG waveforms that are free of artifacts. PPGs are highly susceptible to motion, which can distort the PPG-derived data. Part of the motion artifacts are considered to result from sensor-tissue motion and sensor deformation. It is hypothesized that these motion artifacts correlate with movement of the sensor with respect to the skin. This hypothesis has been proven true in a laboratory setup. In vitro PPGs have been measured in a skin perfusion phantom that is illuminated by a laser diode. Optical motion artifacts are generated in the PPG by translating the laser diode with respect to the PPG photodiode. The optical motion artifacts have been reduced significantly in vitro, by using a normalized least-mean-square algorithm with only a single coefficient that uses the laser's displacement as a reference for the motion artifacts. Laser displacement has been measured accurately via self-mixing interferometry by a compact laser diode with a ball lens integrated into the package, which can be easily integrated into a commercial sensor.

  7. A Novel Semiblind Signal Extraction Approach for the Removal of Eye-Blink Artifact from EEGs

    Directory of Open Access Journals (Sweden)

    Saied Sanei

    2008-04-01

    Full Text Available A novel blind signal extraction (BSE scheme for the removal of eye-blink artifact from electroencephalogram (EEG signals is proposed. In this method, in order to remove the artifact, the source extraction algorithm is provided with an estimation of the column of the mixing matrix corresponding to the point source eye-blink artifact. The eye-blink source is first extracted and then cleaned, artifact-removed EEGs are subsequently reconstructed by a deflation method. The a priori knowledge, namely, the vector, corresponding to the spatial distribution of the eye-blink factor, is identified by fitting a space-time-frequency (STF model to the EEG measurements using the parallel factor (PARAFAC analysis method. Hence, we call the BSE approach semiblind signal extraction (SBSE. This approach introduces the possibility of incorporating PARAFAC within the blind source extraction framework for single trial EEG processing applications and the respected formulations. Moreover, aiming at extracting the eye-blink artifact, it exploits the spatial as well as temporal prior information during the extraction procedure. Experiments on synthetic data and real EEG measurements confirm that the proposed algorithm effectively identifies and removes the eye-blink artifact from raw EEG measurements.

  8. A Novel Semiblind Signal Extraction Approach for the Removal of Eye-Blink Artifact from EEGs

    Science.gov (United States)

    Nazarpour, Kianoush; Mohseni, Hamid R.; Hesse, Christian W.; Chambers, Jonathon A.; Sanei, Saeid

    2008-12-01

    A novel blind signal extraction (BSE) scheme for the removal of eye-blink artifact from electroencephalogram (EEG) signals is proposed. In this method, in order to remove the artifact, the source extraction algorithm is provided with an estimation of the column of the mixing matrix corresponding to the point source eye-blink artifact. The eye-blink source is first extracted and then cleaned, artifact-removed EEGs are subsequently reconstructed by a deflation method. The a priori knowledge, namely, the vector, corresponding to the spatial distribution of the eye-blink factor, is identified by fitting a space-time-frequency (STF) model to the EEG measurements using the parallel factor (PARAFAC) analysis method. Hence, we call the BSE approach semiblind signal extraction (SBSE). This approach introduces the possibility of incorporating PARAFAC within the blind source extraction framework for single trial EEG processing applications and the respected formulations. Moreover, aiming at extracting the eye-blink artifact, it exploits the spatial as well as temporal prior information during the extraction procedure. Experiments on synthetic data and real EEG measurements confirm that the proposed algorithm effectively identifies and removes the eye-blink artifact from raw EEG measurements.

  9. Wavelet-based artifact identification and separation technique for EEG signals during galvanic vestibular stimulation.

    Science.gov (United States)

    Adib, Mani; Cretu, Edmond

    2013-01-01

    We present a new method for removing artifacts in electroencephalography (EEG) records during Galvanic Vestibular Stimulation (GVS). The main challenge in exploiting GVS is to understand how the stimulus acts as an input to brain. We used EEG to monitor the brain and elicit the GVS reflexes. However, GVS current distribution throughout the scalp generates an artifact on EEG signals. We need to eliminate this artifact to be able to analyze the EEG signals during GVS. We propose a novel method to estimate the contribution of the GVS current in the EEG signals at each electrode by combining time-series regression methods with wavelet decomposition methods. We use wavelet transform to project the recorded EEG signal into various frequency bands and then estimate the GVS current distribution in each frequency band. The proposed method was optimized using simulated signals, and its performance was compared to well-accepted artifact removal methods such as ICA-based methods and adaptive filters. The results show that the proposed method has better performance in removing GVS artifacts, compared to the others. Using the proposed method, a higher signal to artifact ratio of -1.625 dB was achieved, which outperformed other methods such as ICA-based methods, regression methods, and adaptive filters.

  10. Developments of metal artifact reduction methods of cone-beam computed tomography

    Science.gov (United States)

    Shih, Kun-Long; Jin, Shih-Chun D.; Chen, Jyh-Cheng

    2014-09-01

    While clinical applications of cone-beam computed tomography (CBCT) have expanded, current CBCT technology has limitations due to the streak artifacts caused by metallic objects. The aim of this work was to develop an efficient and accurate metal data interpolation in sinogram domain to achieve artifact suppression and to improve CT image quality. In this study, we propose three interpolation methods for the metal projection data. Metal objects are segmented in raw data and replacement of the segmented regions by new values is done using three interpolation schemes, (1) replacing the raw data by the simple threshold value (thresholding method), (2) reducing the raw data to half of the value which is over threshold value (modification method), (3) using the inpainting interpolation (inpainting method). Our references are the CBCT images of the phantoms without the metal implants. The performance was evaluated by comparing the differences of root mean square error (RMSE) before and after metal artifact reduction (MAR). All the metal artifacts were reduced effectively. Metal artifacts reduction using method (1) performs the best, which improve the differences of RMSE more than 60%. This study indicates that metal artifacts can be reduced effectively by manipulating metal projection data.

  11. Classroom Teachers and Classroom Research. JALT Applied Materials.

    Science.gov (United States)

    Griffee, Dale T., Ed.; Nunan, David, Ed.

    This collection of papers leads classroom language teachers through the process of developing and completing a classroom research project. Arranged in four sections, they include: "Language Teaching and Research" (David Nunan); "Where Are We Now? Trends, Teachers, and Classroom Research" (Dale T. Griffee); "First Things First: Writing the Research…

  12. Classroom Discussions: Possibilities and Limitations for Democratic Classroom Practices

    Science.gov (United States)

    Aasebø, Turid Skarre

    2017-01-01

    Are students offered possibilities to experience democratic practice in classrooms? Using an analysis of empirical data from classroom discussions in lower secondary school, this article identifies and explores two different types of classroom discussions which give students different positions: a conversation in which students are positioned as…

  13. Using Internet Artifacts to Profile a Child Pornography Suspect

    Directory of Open Access Journals (Sweden)

    Marcus K. Rogers

    2014-03-01

    behavioral analysis process described, but the ability to infer the predilection for being a consumer of child pornography based on Internet artifacts may prove to be a powerful tool for investigators.

  14. Sherlock Holmes in the Classroom.

    Science.gov (United States)

    Faia, Jean E.

    1988-01-01

    Describes a three-day classroom activity combining criminal investigations and scientific skills, especially observation skills. Provides detailed classroom procedures with an illustration of eight basic fingerprint patterns and a classification chart. (YP)

  15. The flipped classroom

    DEFF Research Database (Denmark)

    Triantafyllou, Evangelia

    2015-01-01

    class time is devoted to clarifications and application of this knowledge. The hypothesis is that there could be deep and creative discussions when teacher and students physically meet. This paper presents design considerations for flipped classrooms, and discusses how Moodle can facilitate......One of the novel ideas in teaching that heavily relies on current technology is the “flipped classroom” approach. In a flipped classroom the traditional lecture and homework sessions are inverted. Students are provided with online material in order to gain necessary knowledge before class, while...... communication and information sharing in such classrooms. Furthermore, it provides guidelines for supporting out-of-class instruction in the flipped model by using quizzes and feedback in Moodle, and comments on the potential to follow student use of resources by using Moodle reports. This paper concludes...

  16. When classroom becomes school

    DEFF Research Database (Denmark)

    Noer, Vibeke Røn

    of the studies primarily focus on the clinical learning context. Based upon educational ethnographic studies following nursing students in and out of both learning contexts (Noer, 2016) and by drawing on concepts of formation (Benner, 2011), learning strategies (Borgnakke, 2008) and positioning strategies...... (Christensen, 2013), this presentation will focus on ‘what’s happening in the classroom’ when classroom is ‘school’ among fellow students opposed to ‘real nursing practice’ among future colleagues. Focusing on student strategies in the classroom, the presentation will further elaborate on the inherent...... & Perrenoud, 2006). In Denmark alone changes have been made numerously times in the last two decades. Concurrently, a considerable amount of studies has been published focusing on the nursing education, stressing a call for transformation. Division of learning contexts into clinical and classroom settings...

  17. Inverting the Linear Algebra Classroom

    Science.gov (United States)

    Talbert, Robert

    2014-01-01

    The inverted classroom is a course design model in which students' initial contact with new information takes place outside of class meetings, and students spend class time on high-level sense-making activities. The inverted classroom model is so called because it inverts or "flips" the usual classroom design where typically class…

  18. Exotic Rickettsiae in Ixodes ricinus: fact or artifact?

    NARCIS (Netherlands)

    Tijsse-Klasen, E.; Fonville, M.; Overbeek, van L.S.; Reimerink, J.H.J.; Sprong, H.

    2010-01-01

    Several pathogenic Rickettsia species can be transmitted via Ixodes ricinus ticks to humans and animals. Surveys of I. ricinus for the presence of Rickettsiae using part of its 16S rRNA gene yield a plethora of new and different Rickettsia sequences. Interpreting these data is sometimes difficult

  19. Evaluation of three commercial metal artifact reduction methods for CT simulations in radiation therapy

    Directory of Open Access Journals (Sweden)

    Jessie Y Huang

    2014-03-01

    Full Text Available Purpose: To evaluate the success of three commercial metal artifact reduction methods (MAR in the context of radiation therapy treatment planning.Methods: Three MAR strategies were evaluated: Philips O-MAR, monochromatic imaging using Gemstone Spectral Imaging (GSI dual energy CT, and monochromatic imaging with metal artifact reduction software (GSI-MARs. The Gammex RMI 467 tissue characterization phantom with several metal rods and two anthropomorphic phantoms (pelvic phantom with hip prosthesis and head phantom with dental fillings, were scanned with and without metals (baseline. Each MAR method was evaluated based on CT number accuracy, metal size accuracy, and reduction in the severity of streak artifacts. CT number difference maps between the baseline and metal scan images were calculated, and the severity of streak artifacts was quantified using the percentage of pixels with > 40 HU error (“bad pixels”.Results: Philips O-MAR generally reduced HU errors in the RMI phantom. However, increased errors and induced artifacts were observed for lung materials. GSI monochromatic 70keV images generally showed similar HU errors as conventional 120kVp imaging, while 140keV images reduced HU errors. All the imaging techniques represented the diameter of a stainless steel rod to within ±1.6mm (2 pixels. For the hip prosthesis, O-MAR reduced the average % bad pixels from 47% to 32%. For GSI 140keV imaging, the % bad pixels was reduced from 37% to 29% compared to 120kVp imaging, and GSI-MARs further reduced it to 12%. For the head phantom, none of the MAR methods was particularly successful.Conclusion: O-MAR resulted in consistent artifact reduction but exhibited induced artifacts for metals located near lung tissue. GSI imaging at 140keV gave consistent reduction in HU errors and severity of artifacts. GSI-MARs at 140keV was the most successful MAR method for the hip prosthesis but exhibited induced artifacts at the edges of metals in some cases

  20. Postoperative susceptibility artifact during magnetic resonance imaging of the vertebral column in two dogs and a cat.

    Science.gov (United States)

    Freer, Sean R; Scrivani, Peter V

    2008-01-01

    In humans that have undergone cervical diskectomy, magnetic susceptibility artifacts are often found on postoperative magnetic resonance (MR) images of the affected region. In some patients, these artifacts complicate image interpretation, while in others the artifacts lead to a false diagnosis of spinal cord compression. We describe two dogs and one cat that had susceptibility artifacts visible in postoperative MR images. In each patient, multiple, small-to-large, distinct, magnetic susceptibility artifacts were visible along the surgery site. In both dogs, interpretation was impossible and subsequently computed tomography (CT) was performed. During CT, no cause for the MR artifact was identified. The most likely source of the artifact is microscopic metal fragments from the burr, suction tip or other surgical instruments, but other possible causes include hemorrhage or paramagnetic suture material. These artifacts may cause difficulty in interpretation or suggest a clinical problem. MR imaging therefore might not be the most appropriate examination for patients following certain types of surgery due to the possibility of susceptibility artifacts. Although this artifact probably is common in the postoperative patient, the frequency that this finding will prevent accurate diagnosis is unknown.

  1. Improved Image Quality in Head and Neck CT Using a 3D Iterative Approach to Reduce Metal Artifact.

    Science.gov (United States)

    Wuest, W; May, M S; Brand, M; Bayerl, N; Krauss, A; Uder, M; Lell, M

    2015-10-01

    Metal artifacts from dental fillings and other devices degrade image quality and may compromise the detection and evaluation of lesions in the oral cavity and oropharynx by CT. The aim of this study was to evaluate the effect of iterative metal artifact reduction on CT of the oral cavity and oropharynx. Data from 50 consecutive patients with metal artifacts from dental hardware were reconstructed with standard filtered back-projection, linear interpolation metal artifact reduction (LIMAR), and iterative metal artifact reduction. The image quality of sections that contained metal was analyzed for the severity of artifacts and diagnostic value. A total of 455 sections (mean ± standard deviation, 9.1 ± 4.1 sections per patient) contained metal and were evaluated with each reconstruction method. Sections without metal were not affected by the algorithms and demonstrated image quality identical to each other. Of these sections, 38% were considered nondiagnostic with filtered back-projection, 31% with LIMAR, and only 7% with iterative metal artifact reduction. Thirty-three percent of the sections had poor image quality with filtered back-projection, 46% with LIMAR, and 10% with iterative metal artifact reduction. Thirteen percent of the sections with filtered back-projection, 17% with LIMAR, and 22% with iterative metal artifact reduction were of moderate image quality, 16% of the sections with filtered back-projection, 5% with LIMAR, and 30% with iterative metal artifact reduction were of good image quality, and 1% of the sections with LIMAR and 31% with iterative metal artifact reduction were of excellent image quality. Iterative metal artifact reduction yields the highest image quality in comparison with filtered back-projection and linear interpolation metal artifact reduction in patients with metal hardware in the head and neck area. © 2015 by American Journal of Neuroradiology.

  2. Reference layer adaptive filtering (RLAF) for EEG artifact reduction in simultaneous EEG-fMRI.

    Science.gov (United States)

    Steyrl, David; Krausz, Gunther; Koschutnig, Karl; Edlinger, Günter; Müller-Putz, Gernot R

    2017-04-01

    Simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) combines advantages of both methods, namely high temporal resolution of EEG and high spatial resolution of fMRI. However, EEG quality is limited due to severe artifacts caused by fMRI scanners. To improve EEG data quality substantially, we introduce methods that use a reusable reference layer EEG cap prototype in combination with adaptive filtering. The first method, reference layer adaptive filtering (RLAF), uses adaptive filtering with reference layer artifact data to optimize artifact subtraction from EEG. In the second method, multi band reference layer adaptive filtering (MBRLAF), adaptive filtering is performed on bandwidth limited sub-bands of the EEG and the reference channels. The results suggests that RLAF outperforms the baseline method, average artifact subtraction, in all settings and also its direct predecessor, reference layer artifact subtraction (RLAS), in lower (EEG frequency ranges. Effectivity is determined by visual inspection, as well as root-mean-square voltage reduction and power reduction of EEG provided that physiological EEG components such as occipital EEG alpha power and visual evoked potentials (VEP) are preserved. We demonstrate that both, RLAF and MBRLAF, improve VEP quality. For that, we calculate the mean-squared-distance of single trial VEP to the mean VEP and estimate single trial VEP classification accuracies. We found that the average mean-squared-distance is lowest and the average classification accuracy is highest after MBLAF. RLAF was second best. In conclusion, the results suggests that RLAF and MBRLAF are potentially very effective in improving EEG quality of simultaneous EEG-fMRI. Highlights We present a new and reusable reference layer cap prototype for simultaneous EEG-fMRI We introduce new algorithms for reducing EEG artifacts due to simultaneous fMRI The algorithms combine a reference layer and adaptive filtering Several

  3. Combining EEG and eye tracking: Identification, characterization and correction of eye movement artifacts in electroencephalographic data

    Directory of Open Access Journals (Sweden)

    Michael ePlöchl

    2012-10-01

    Full Text Available Eye movements introduce large artifacts to electroencephalographic recordings (EEG and thus render data analysis difficult or even impossible. Trials contaminated by eye movement and blink artifacts have to be discarded, hence in standard EEG-paradigms subjects are required to fixate on the screen. To overcome this restriction, several correction methods including regression and blind source separation have been proposed. Yet, there is no automated standard procedure established. By simultaneously recording eye movements and 64-channel-EEG during a guided eye movement paradigm, we show that eye movement artifacts consist of several components, which arise from different sources. These include corneo-retinal dipole changes, saccadic spike potentials and eyelid movements. Moreover, we demonstrate that depending on electrode site, gaze direction and choice of reference these components contribute differently to the measured signal. Therefore they cannot be removed by regression-based correction methods, as these inevitably over- or under-correct individual artifact components. Finally we propose a correction procedure based on Independent Component Analysis (ICA. This procedure uses eye tracker information to reliably and objectively identify eye-artifact related ICA-components in an automated manner. We demonstrate that this approach allows removing or substantially reducing ocular artifacts including microsaccades without affecting the signal originating from brain sources. In conclusion the proposed method does not only provide a tool for detecting and correcting eye artifacts in standard EEG-paradigms but it also permits to study EEG-activity during eye tracking experiments and thus to investigate neural mechanisms of eye movement control and visual attention under natural conditions.

  4. Separating drought effects from roof artifacts on ecosystem processes in a grassland drought experiment.

    Science.gov (United States)

    Vogel, Anja; Fester, Thomas; Eisenhauer, Nico; Scherer-Lorenzen, Michael; Schmid, Bernhard; Weisser, Wolfgang W; Weigelt, Alexandra

    2013-01-01

    1: Given the predictions of increased drought probabilities under various climate change scenarios, there have been numerous experimental field studies simulating drought using transparent roofs in different ecosystems and regions. Such roofs may, however, have unknown side effects, called artifacts, on the measured variables potentially confounding the experimental results. A roofed control allows the quantification of potential artifacts, which is lacking in most experiments. 2: We conducted a drought experiment in experimental grasslands to study artifacts of transparent roofs and the resulting effects of artifacts on ecosystems relative to drought on three response variables (aboveground biomass, litter decomposition and plant metabolite profiles). We established three drought treatments, using (1) transparent roofs to exclude rainfall, (2) an unroofed control treatment receiving natural rainfall and (3) a roofed control, nested in the drought treatment but with rain water reapplied according to ambient conditions. 3: Roofs had a slight impact on air (+0.14°C during night) and soil temperatures (-0.45°C on warm days, +0.25°C on cold nights), while photosynthetically active radiation was decreased significantly (-16%). Aboveground plant community biomass was reduced in the drought treatment (-41%), but there was no significant difference between the roofed and unroofed control, i.e., there were no measurable roof artifact effects. 4: Compared to the unroofed control, litter decomposition was decreased significantly both in the drought treatment (-26%) and in the roofed control treatment (-18%), suggesting artifact effects of the transparent roofs. Moreover, aboveground metabolite profiles in the model plant species Medicago x varia were different from the unroofed control in both the drought and roofed control treatments, and roof artifact effects were of comparable magnitude as drought effects. 5: Our results stress the need for roofed control treatments

  5. Efficient reference-free adaptive artifact cancellers for impedance cardiography based remote health care monitoring systems.

    Science.gov (United States)

    Mallam, Madhavi; Rao, K Chandra Bhutan

    2016-01-01

    In this paper, a new model for adaptive artifact cancelation in impedance cardiography (ICG) signals is presented. It is a hybrid model based on wavelet decomposition and an adaptive filter. A novel feature of this model is the implementation of reference-free adaptive artifact cancellers (AAC). For this implementation, the reference signal is constructed using a wavelet transformation. During critical conditions the filter weights may be negative and cause an imbalance in the convergence. To overcome this problem, we introduce non-negative adaptive algorithms in the proposed artifact canceller. To accelerate the performance of the AAC, we propose exponential non-negative and normalized non-negative algorithms to update the filter coefficients. The computational complexity of the filtering section in a remote health care system is important to avoid inter-symbol interference of the incoming samples. This can be achieved by combining sign-based algorithms with the adaptive filtering section. Finally, several AACs are developed using variants of the non-negative algorithms and performance measures are computed and compared. All of the proposed AACs are tested on actual ICG signals. Among the AACs evaluated, sign regressor normalized non-negative LMS (SRN(3)LMS) based adaptive artifact canceller achieves highest signal to noise ratio (SNR). The SNR achieved by this algorithm in baseline wander artifact elimination is 8.5312 dBs, in electrode muscle artifact elimination is 7.5908 dBs and in impedance measurement artifact elimination is 8.4231 dBs.

  6. sEMG during Whole-Body Vibration Contains Motion Artifacts and Reflex Activity.

    Science.gov (United States)

    Lienhard, Karin; Cabasson, Aline; Meste, Olivier; Colson, Serge S

    2015-03-01

    The purpose of this study was to determine whether the excessive spikes observed in the surface electromyography (sEMG) spectrum recorded during whole-body vibration (WBV) exercises contain motion artifacts and/or reflex activity. The occurrence of motion artifacts was tested by electrical recordings of the patella. The involvement of reflex activity was investigated by analyzing the magnitude of the isolated spikes during changes in voluntary background muscle activity. Eighteen physically active volunteers performed static squats while the sEMG was measured of five lower limb muscles during vertical WBV using no load and an additional load of 33 kg. In order to record motion artifacts during WBV, a pair of electrodes was positioned on the patella with several layers of tape between skin and electrodes. Spectral analysis of the patella signal revealed recordings of motion artifacts as high peaks at the vibration frequency (fundamental) and marginal peaks at the multiple harmonics were observed. For the sEMG recordings, the root mean square of the spikes increased with increasing additional loads (p activity might be contained in the isolated spikes, as identical behavior has been found for stretch reflex responses evoked during direct vibration. In conclusion, the spikes visible in the sEMG spectrum during WBV exercises contain motion artifacts and possibly reflex activity. Key pointsThe spikes observed in the sEMG spectrum during WBV exercises contain motion artifacts and possibly reflex activityThe motion artifacts are more pronounced in the first spike than the following spikes in the sEMG spectrumReflex activity during WBV exercises is enhanced with an additional load of approximately 50% of the body mass.

  7. Exploration of Methodological and Participant-Related Influences on the Number of Artifacts in ERP Data

    Directory of Open Access Journals (Sweden)

    Stephanie M. Shields

    2017-11-01

    Full Text Available Event-related potential (ERP data has low signal-to-noise ratio, requiring the conduction of a large number of trials in order to collect sufficient amounts of data for subsequent analysis. Therefore, it would be highly beneficial if researchers could minimize the number of artifacts that occur in the data, minimizing the number of discarded trials and the total number of trials needed. This study thus examined connections between the number of trials that have to be eliminated due to artifacts and a set of methodological variables, physical considerations, and individual differences. In half of the electroencephalography (EEG data collection blocks, naïve undergraduate participants were asked not to blink for the duration of the block (approximately 2.5 minutes, but in the other half, the stimulus set included blinking cues to give participants a chance to blink during blocks. The number of artifacts did not differ based on whether participants were cued to blink during blocks nor which type of block participants experienced first. However, the first block had significantly more artifacts than other blocks, and the third block had significantly fewer. Participants who had previously known one or both investigators had significantly fewer artifacts in their data than participants who had not, but no significant relationship was found between the number of artifacts and any other individual difference or physical consideration examined. These results imply that researchers could preemptively reduce the number of artifacts in their EEG data by including practice blocks and recruiting friends or acquaintances for studies if possible. Based on subjective, unsolicited participant feedback, the authors also recommend having blink cues in data collection blocks in order to make the task more comfortable for participants. Future studies with similar aims could use different equipment setups, e.g. electrode caps, and experimental manipulation of

  8. An Image-Based Reduction of Metal Artifacts in Computed Tomography.

    Science.gov (United States)

    Pua, Rizza; Wi, Sunhee; Park, Miran; Lee, Jung-Ryun; Cho, Seungryong

    2016-01-01

    Various strategies have been developed in the past to reduce the excessive effects of metal artifacts in computed tomography images. From straightforward sinogram inpainting-based methods to computationally expensive iterative methods, all have been successful in improving the image quality up to a certain degree. We propose a novel image-based metal artifact subtraction method that achieves a superior image quality and at the same time provides a quantitatively more accurate image. Our proposed method consists of prior image-based sinogram inpainting, metal sinogram extraction, and metal artifact image subtraction. Reconstructing the metal images from the extracted metal-contaminated portions in the sinogram yields a streaky image that eventually can be subtracted from the uncorrected image. The prior image is reconstructed from the sinogram that is free from the metal-contaminated portions by use of a total variation (TV) minimization algorithm, and the reconstructed prior image is fed into the forward projector so that the missing portions in the sinogram can be recovered. Image quality of the metal artifact-reduced images on selected areas was assessed by the structure similarity index for the simulated data and SD for the real dental data. Simulation phantom studies showed higher structure similarity index values for the proposed metal artifact reduction (MAR) images than the standard MAR images. Thus, more artifact suppression was observed in proposed MAR images. In real dental phantom data study, lower SD values were calculated from the proposed MAR images. The findings in real human arm study were also consistent with the results in all phantom studies. Thus, compared with standard MAR images, lesser artifact intensity was exhibited by the proposed MAR images. From the quantitative calculations, our proposed method has shown to be effective and superior to the conventional approach in both simulation and real dental phantom cases.

  9. The flipped classroom: A learning model to increase student engagement not academic achievement

    Directory of Open Access Journals (Sweden)

    Masha Smallhorn

    2017-07-01

    Full Text Available A decrease in student attendance at lectures both nationally and internationally, has prompted educators to re-evaluate their teaching methods and investigate strategies which promote student engagement. The flipped classroom model, grounded in active learning pedagogy, transforms the face-to-face classroom. Students prepare for the flipped classroom in their own time by watching short online videos and completing readings. Face-to-face time is used to apply learning through problem-solving with peers. To improve the engagement and learning outcomes of our second year cohort, lectures were replaced with short online videos and face-to-face time was spent in a flipped classroom. The impact of the flipped classroom was analysed through surveys, attendance records, learning analytics and exam data before and after the implementation of the flipped classroom. Results suggest an increase in student engagement and a positive attitude towards the learning method. However, there were no measurable increases in student learning outcomes.

  10. Classroom Contexts for Creativity

    Science.gov (United States)

    Beghetto, Ronald A.; Kaufman, James C.

    2014-01-01

    Various factors influence the development of creative potential, including everything from individual differences to the kinds of experiences and opportunities that creators experience throughout the lifespan. When it comes to nurturing creativity in the classroom, the learning environment is one of the most important factors--determining, in…

  11. THE CLASSROOM AIDE.

    Science.gov (United States)

    FITZPATRICK, MILDRED

    TO RELIEVE THE NON-INSTRUCTIONAL BURDEN UPON THE CLASSROOM TEACHER, THE QUEMADO PUBLIC SCHOOLS EXPERIMENTED WITH A TEACHER AIDE PROGRAM, UTILIZING A SINGLE TEACHER AIDE IN ELEMENTARY LANGUAGE ARTS AND HIGH SCHOOL PROGRAMED MATHEMATICS THE FIRST YEAR OF THE PROJECT. AS A RESULT OF THE EXPERIMENT'S SUCCESS, THE FOLLOWING SCHOOL YEAR (1963-1964)…

  12. In the Classroom.

    Science.gov (United States)

    1997

    Fourteen conference papers on classroom techniques for second language teaching are presented, including: "Cooperative Learning at the Post-Secondary Level in Japan" (Steve McGuire, Patricia Thornton, David Kluge); "Shared Inquiry Fosters Critical Thinking Skills in EFL Students" (Carol Browning, Jerold Halvorsen, Denise…

  13. Singing Smoothes Classroom Transitions

    Science.gov (United States)

    Mathews, Sarah E.

    2012-01-01

    Just as humming a merry tune helped Snow White and her furry animal friends to quickly clean a filthy cottage in the movie "Snow White and the Seven Dwarfs" (Disney & Cottrell, 1937), singing can be an effective way to help keep young children fully engaged during classroom transitions. The purposes of this article are to: (1) consider why…

  14. Creating a Smart Classroom

    Science.gov (United States)

    Domermuth, David

    2005-01-01

    This article provides a description of an affordable, smart classroom built for the Technology Department at Appalachian State university. The system consists of three basic components: a home theater combo, a tablet PC, and a digital projector, costing a total of $7,300, or $8,800 if a podium, screen, and projector mount are purchased. The…

  15. The Classroom Animal: Snails.

    Science.gov (United States)

    Kramer, David S.

    1985-01-01

    Points out that snails are interesting and easily-managed classroom animals. One advantage of this animal is that it requires no special attention over weekends or holidays. Background information, anatomy, reproduction, and feeding are discussed, along with suggestions for housing aquatic and/or land snails. (DH)

  16. The Paperless Music Classroom

    Science.gov (United States)

    Giebelhausen, Robin

    2016-01-01

    In an age where the world is becoming ever more aware of paper consumption, educators are turning toward technology to cut back on paper waste. Besides the environmental reasons, a paperless music classroom helps students develop their musicianship in new and exciting ways. This article will look at the considerations for setting up a paperless…

  17. Flipping the Classroom Revisited

    Science.gov (United States)

    Riendeau, Diane

    2013-02-01

    I received many emails following the first column on flipping the classroom. Many of my local colleagues also approached me at our physics alliance, Physics Northwest. Teachers are very interested in this new pedagogy. As I result, I wanted to share some more videos to inspire you.

  18. Animals in the Classroom

    Science.gov (United States)

    Roy, Ken

    2011-01-01

    Use of animals in middle school science classrooms is a curriculum component worthy of consideration, providing proper investigation and planning are addressed. A responsible approach to this action, including safety, must be adopted for success. In this month's column, the author provides some suggestions on incorporating animals into the…

  19. Tips from the Classroom.

    Science.gov (United States)

    Shiffman, Doris Yaffe; And Others

    1992-01-01

    Discusses setting up conversation tables on campus in cross-cultural interaction among native and nonnative speakers, presents ways to teach proverbs in the advanced classroom, describes how to use Aesop's fables to integrate all learning skills, tells how to teach make/do, and suggests ways to improve communicative skills for better accuracy and…

  20. Flexible Classroom Furniture

    Science.gov (United States)

    Kim Hassell,

    2011-01-01

    Classroom design for the 21st-century learning environment should accommodate a variety of learning skills and needs. The space should be large enough so it can be configured to accommodate a number of learning activities. This also includes furniture that provides flexibility and accommodates collaboration and interactive work among students and…

  1. My Classroom: Philippines

    Science.gov (United States)

    Santoro, Cerise

    2017-01-01

    In his first teaching assignment, as a fifth-grade English teacher, Edgar Manaran had only 20 desks for 48 students. Yet he was able to apply productive classroom strategies throughout his 25-hour teaching week. Some of his students sat on plastic chairs due to the shortage of desks, but that did not change the dynamic of Mr. Manaran's classes. He…

  2. Effective Classroom Management

    Science.gov (United States)

    Mansor, Azlin Norhaini; Eng, Wong Kim; Rasul, Mohamad Sattar; Hamzah, Mohd Izham Mohd; Hamid, Aida Hanim A.

    2012-01-01

    This paper attempts to explore and identify the characteristics of an effective teacher who teaches English as a second language to 10 year old students from different ethnics, various social economic background and multi-level language ability, at a private primary school in Malaysia. The study focused on classroom management using a case study…

  3. Classroom Social Signal Analysis

    Science.gov (United States)

    Raca, Mirko; Dillenbourg, Pierre

    2014-01-01

    We present our efforts towards building an observational system for measuring classroom activity. The goal is to explore visual cues which can be acquired with a system of video cameras and automatically processed to enrich the teacher's perception of the audience. The paper will give a brief overview of our methodology, explored features, and…

  4. A Monopoly Classroom Experiment.

    Science.gov (United States)

    Oxoby, Robert J.

    2001-01-01

    Uses a simple classroom experiment to develop the economic model of monopoly. Introduces students to the nature of the monopoly problem and motivates them to think of the associated effects. Highlights the role of information and fairness ideals in determining economic outcomes. (RLH)

  5. Bibliotherapy for Classroom Management

    Science.gov (United States)

    Elsenman, Gordon; Harper, Rebecca

    2016-01-01

    The focus and goal of classroom management should be first and foremost learning. When trying to prevent interruptions to learning, or dealing with interruptions to learning when they occur, teachers need to move beyond simply imposing a consequence and assuming students have learned from the interaction. Students need to be taught the skills and…

  6. CONSERVATION AND THE CLASSROOM

    African Journals Online (AJOL)

    field work but who don't attempt it. I can also understand ... Neglected Outdoor Classroom' by Frank Opie in the. May 1986 issue of this ... Group A consited of Biology teachers who went with Mr. A. Gubb, an ecological botanist on the museum staff. Worksheets had been carefully prepared by Miss. Tietz and Mrs. Lloyd to ...

  7. The Flipped Classroom

    National Research Council Canada - National Science Library

    Bill Tucker

    2012-01-01

    ... class time. It's called "the flipped classroom." While there is no one model, the core idea is to flip the common instructional approach: With teacher-created videos and interactive lessons, instruction that used to occur in class is now accessed at home, in advance of class. Class becomes the place to work through problems, advance co...

  8. Assessing Classroom Assessment Techniques

    Science.gov (United States)

    Simpson-Beck, Victoria

    2011-01-01

    Classroom assessment techniques (CATs) are teaching strategies that provide formative assessments of student learning. It has been argued that the use of CATs enhances and improves student learning. Although the various types of CATs have been extensively documented and qualitatively studied, there appears to be little quantitative research…

  9. Teachers' Classroom Assessment Practices

    Science.gov (United States)

    Frey, Bruce B.; Schmitt, Vicki L.

    2010-01-01

    This study examined classroom assessment practices of 3rd- through 12th-grade teachers in a Midwestern state. In addition to determining the frequency with which specific assessment item formats were utilized, the level of use of selected "best practice" approaches to assessment was considered ("performance-based assessment,…

  10. Examining the knowledge and capacity of elementary teachers to implement classroom physical activity breaks

    Directory of Open Access Journals (Sweden)

    Danae M. Dinkel

    2016-09-01

    Full Text Available This study examined teachers’ zone of proximal development for classroom physical activity breaks by assessing teachers’ knowledge and capacity for implementing classroom physical activity breaks. Five school districts of various sizes (n=346 teachers took part in a short online survey. Descriptive statistics were calculated and chi-square analyses were used to identify differences between districts. Almost all teachers utilized classroom physical activity to some extent. A third of teachers who stated they implemented classroom physical activity, experienced barriers to implementation. A majority of teachers were interested in learning more about classroom physical activity. There were significant differences between districts on the number of days per week classroom physical activity was integrated, the frequency of collaboration that occurred between teachers, the percentage of teachers who experienced barriers, and preferred delivery method of professional development. These findings support the importance of identifying teachers’ zone of proximal development to increase the use of classroom physical activity breaks. Understanding teachers’ knowledge and capacity for implementing classroom physical activity breaks can allow educational professionals to shift the implementation of classroom physical activity beyond sporadic use by isolated teachers and schools to a more systematic and consistent delivery across classrooms and throughout districts.

  11. Examining the Knowledge and Capacity of Elementary Teachers to Implement Classroom Physical Activity Breaks

    Directory of Open Access Journals (Sweden)

    Danae M. DINKEL

    2016-09-01

    Full Text Available This study examined teachers’ zone of proximal development for classroom physical activity breaks by assessing teachers’ knowledge and capacity for implementing classroom physical activity breaks. Five school districts of various sizes (n=346 teachers took part in a short online survey. Descriptive statistics were calculated and chi-square analyses were used to identify differences between districts. Almost all teachers utilized classroom physical activity to some extent. A third of teachers who stated they implemented classroom physical activity, experienced barriers to implementation. A majority of teachers were interested in learning more about classroom physical activity. There were significant differences between districts on the number of days per week classroom physical activity was integrated, the frequency of collaboration that occurred between teachers, the percentage of teachers who experienced barriers, and preferred delivery method of professional development. These findings support the importance of identifying teachers’ zone of proximal development to increase the use of classroom physical activity breaks. Understanding teachers’ knowledge and capacity for implementing classroom physical activity breaks can allow educational professionals to shift the implementation of classroom physical activity beyond sporadic use by isolated teachers and schools to a more systematic and consistent delivery across classrooms and throughout districts.

  12. Cell Phones in the Classroom: Preservice Teachers' Perceptions

    Science.gov (United States)

    Thomas, Kevin; O'Bannon, Blanche

    2013-01-01

    This study employed a survey to examine the perceptions of 92 preservice teachers enrolled at a small Midwestern liberal arts university regarding their support of the use of cell phones in the classroom, the benefits of specific cell phone features for school-related work, and the instructional benefits of and barriers to using cell phones in the…

  13. Creativity in the Early Childhood Classroom: Perspectives of Preservice Teachers

    Science.gov (United States)

    Eckhoff, Angela

    2011-01-01

    This study examined how preservice teachers view the nature and role of creativity in light of the complexities of contemporary early childhood classrooms. A multiple methods approach was utilized and data were collected with the Questionnaire Examining Student Teachers' Beliefs about Creativity (Diakidoy & Kanari, 1999) survey instrument and…

  14. Aboriginal English in the Classroom: An Asset or a Liability?

    Science.gov (United States)

    Sharifian, Farzad

    2008-01-01

    This paper discusses issues surrounding the use of Australian Aboriginal English in the classroom in the light of a recent survey. Aboriginal English is often correlated with low academic performance and poor school attendance. The paper argues that in any discussion of the school role of students' home talk, a range of factors need to be…

  15. Malaysian Students' Perceptions of Flipped Classroom: A Case Study

    Science.gov (United States)

    Zainuddin, Zamzami; Attaran, Mohammad

    2016-01-01

    The purpose of this study was to evaluate a class in University of Malaya where flipped learning was applied, and to examine students' perceptions and feedback towards flipped classroom. Data were collected using both quantitative and qualitative methods, i.e. survey, focus group and individual interviews. The results indicated that most students…

  16. Differences in Business Undergraduate Perceptions by Preferred Classroom Learning Environment

    Science.gov (United States)

    Blau, Gary; Mittal, Neha; Schirmer, Michael; Ozkan, Bora

    2017-01-01

    Online education continues to grow at business schools. The authors compared undergraduate business student perceptions across three different classroom learning delivery environments: online, hybrid, and face to face. Based on the survey responses using two independent samples, the authors' analyses found that students who preferred online…

  17. Faculty-Preferred Strategies to Promote a Positive Classroom Environment

    Science.gov (United States)

    Black, Laurel Johnson; Wygonik, Mindy L.; Frey, Barbara A.

    2011-01-01

    The purpose of this study was to identify the frequency and seriousness of disruptive student behaviors and the effective strategies used by educators to manage these classroom behaviors. At a mid-sized state university, 228 of 780 faculty members (29.2%) completed a 76-item survey. Results indicated that as faculty members' participation in…

  18. Classroom Teacher's Adherence to Philosophy and Ethics of Home ...

    African Journals Online (AJOL)

    This study analyzed and discussed the philosophy and goals of education, evaluating them on how classroom teachers adhere to the ethics of home economics for sustainable development in Anambra state, Nigeria. A descriptive survey design was used and the sample, randomly selected, was made up of two hundred ...

  19. Preschool Teachers' Views about Classroom Management Models

    Science.gov (United States)

    Sahin-Sak, Ikbal Tuba; Sak, Ramazan; Tezel-Sahin, Fatma

    2018-01-01

    This survey-based quantitative study investigates 310 Turkish preschool teachers' views about classroom management, using the following six models of disciplinary strategy: behavioral change theory, Dreikurs' social discipline model, Canter's assertive discipline model, the Glasser model of discipline, Kounin's model, and Gordon's teacher…

  20. Children's Attitudes and Classroom Interaction in an Intergenerational Education Program

    Science.gov (United States)

    Dunham, Charlotte Chorn; Casadonte, Dominick

    2009-01-01

    This research reports findings from an intergenerational science program, Project Serve, which placed senior volunteers in elementary and junior high science classrooms to assist teachers and augment instruction. Items from the Children's View of Aging survey (Newman, 1997; Newman & Faux, 1997) were administered before and after the project with…

  1. Fostering Ethnic and Religious Harmony through Classroom Language Experiences

    Science.gov (United States)

    Obiekezie, Eucharia Obiageli; Timothy, Alexander Essien

    2015-01-01

    This paper explores ways the classroom environment can fertilise ethnic and religious tolerance in students. In a pre/post test design, 76 students at a university secondary school in the Niger Delta region of Nigeria were randomly selected to respond to a twenty-item survey. Afterwards, the experimental group was exposed to a critical thinking…

  2. Perpetuating Gender Stereotypes in the Classroom: A Teacher Perspective

    Science.gov (United States)

    Gray, Colette; Leith, Helen

    2004-01-01

    This paper discusses findings from a study funded by the Equality Commission for Northern Ireland (NI) to explore the promotion of gender equity in the classroom and the extent to which initial teacher training and in-service courses address gender issues. Data from a questionnaire survey of 344 teachers and the qualitative dimensions of the study…

  3. Evaluating Classroom Time through Systematic Analysis and Student Feedback

    Science.gov (United States)

    Achen, Rebecca M.; Lumpkin, Angela

    2015-01-01

    The purpose of this action research was to examine the use of class time through classroom observation and student feedback. Students', the teacher's, and whole class activities during class were categorized every two minutes. Students also were given pre- and post-course surveys to assess perceptions on lecture time, impact of learning…

  4. Predicting and Curbing Classroom Incivility in Higher Education

    Science.gov (United States)

    Nordstrom, Cynthia R.; Bartels, Lynn K.; Bucy, Jayne

    2009-01-01

    This research examines predictors of uncivil classroom behavior. Uncivil behaviors are disrespectful and disruptive and may include carrying on conversations with others during class, leaving class early, talking on cell phones, etc. Data from a survey of undergraduate students revealed that students who possessed a consumerism orientation,…

  5. Role-Play and Student Engagement: Reflections from the Classroom

    Science.gov (United States)

    Stevens, Rachel

    2015-01-01

    Role-play is viewed by scholars as an effective active learning strategy: it encourages participation among passive learners, adds dynamism to the classroom and promotes the retention of material. But what do students think of role-play? This study surveyed 144 students after a role-play activity in a history course and asked them to identify what…

  6. Using Smart Boards and Manipulatives in the Elementary Science Classroom

    Science.gov (United States)

    Martin, Susan F.; Shaw, Edward L., Jr.; Daughenbaugh, Lynda

    2014-01-01

    This study summarizes the results of a survey administered to 48 elementary schools in the largest school district in a southeastern U.S. state, conducted by university faculty to evaluate the use of SMART Boards and hands-on experiences, the objectives of which were to identify preparedness of elementary classroom teachers in teaching elementary…

  7. Literacy learning in secondary school science classrooms: A cross-case analysis of three qualitative studies

    Science.gov (United States)

    Dillon, Deborah R.; O'Brien, David G.; Moje, Elizabeth B.; Stewart, Roger A.

    The purpose of this cross-case analysis is to illustrate how and why literacy was incorporated into science teaching and learning in three secondary classrooms. Research questions guiding the analysis include: (a) How were literacy events shaped by the teachers' philosophies about teaching science content and teaching students? and (b) How was literacy (reading, writing, and oral language) structured by the teachers and manifested in science lessons? The methodology of ethnography and the theoretical framework of symbolic interactionism were employed in the three studies on which the cross-case analysis was based. The researchers assumed the role of participant observers, collecting data over the period of 1 year in each of the three classrooms. Data, in the form of fieldnotes, interviews, and artifacts, were collected. In each study, data were analyzed using the constant comparative method (Glaser & Strauss, 1967) to determine patterns in the teachers' beliefs about learning and how these influenced their choice of literacy activities. The cross-case analysis was conducted to determine patterns across the three teachers and their classrooms. The findings from this analysis are used to compare how the teachers' philosophies of teaching science and their beliefs about how students learn influenced their use of literacy practices during lessons. Specifically, each teacher's use of literacy activities varied based on his or her beliefs about teaching science concepts. Furthermore, reading, writing, and oral language were important vehicles to learning science concepts within daily classroom activities in the three classrooms.Received: 1 April 1993; Revised: 30 August 1993;

  8. Extensive pneumatized air cells causing susceptibility artifacts in the petrosus part of the ICA.

    Science.gov (United States)

    McCoy, M R; Broussalis, E; Killer, M; Steinbacher, J; Klausner, F

    2017-03-01

    3D-Time-of-flight magnetic-resonance-angiography (TOF MRA) is an established method in vessel analysis. However, many artifacts that occur may lead to a false diagnosis. This retrospective study evaluates the coherence of MR artifacts to extensive pneumatized air cells surrounding the internal carotid artery (ICA) in the petrosus part of the temporal bone. Patients who received 3D-TOF MRA and multidetector helical computed tomography (CT) angiography were registered from April 2012 to April 2013. Of these patients, both ICAs in the petrosus part were analyzed. Vertical maximum intensity projection (MIP) artifacts were graduated as normal, mild to moderate, and severe artifacts. The distinction of the vertical part of the pneumatized air cells was also categorized in three groups, regarding the circumference of the ICA in pneumatization ≤ 90°, between 90° and 180°, and ≥ 180°. A total of 203 vessels were collected for analysis. The more extensive the pneumatized air cells were present, the more band-like artifacts and pseudostenosis at the vertical portion of the petrosus part of the ICA were registered. Careful examination of the source images and evaluation of the size of the pneumatized air cells with CT scan are essential to avoid false positive diagnosis in the distal petrosus part of the ICA.

  9. Neural networks improve brain cancer detection with Raman spectroscopy in the presence of light artifacts

    Science.gov (United States)

    Jermyn, Michael; Desroches, Joannie; Mercier, Jeanne; St-Arnaud, Karl; Guiot, Marie-Christine; Petrecca, Kevin; Leblond, Frederic

    2016-03-01

    It is often difficult to identify cancer tissue during brain cancer (glioma) surgery. Gliomas invade into areas of normal brain, and this cancer invasion is frequently not detected using standard preoperative magnetic resonance imaging (MRI). This results in enduring invasive cancer following surgery and leads to recurrence. A hand-held Raman spectroscopy is able to rapidly detect cancer invasion in patients with grade 2-4 gliomas. However, ambient light sources can produce spectral artifacts which inhibit the ability to distinguish between cancer and normal tissue using the spectral information available. To address this issue, we have demonstrated that artificial neural networks (ANN) can accurately classify invasive cancer versus normal brain tissue, even when including measurements with significant spectral artifacts from external light sources. The non-parametric and adaptive model used by ANN makes it suitable for detecting complex non-linear spectral characteristics associated with different tissues and the confounding presence of light artifacts. The use of ANN for brain cancer detection with Raman spectroscopy, in the presence of light artifacts, improves the robustness and clinical translation potential for intraoperative use. Integration with the neurosurgical workflow is facilitated by accounting for the effect of light artifacts which may occur, due to operating room lights, neuronavigation systems, windows, or other light sources. The ability to rapidly detect invasive brain cancer under these conditions may reduce residual cancer remaining after surgery, and thereby improve patient survival.

  10. Artifact Removal from Biosignal using Fixed Point ICA Algorithm for Pre-processing in Biometric Recognition

    Science.gov (United States)

    Mishra, Puneet; Singla, Sunil Kumar

    2013-01-01

    In the modern world of automation, biological signals, especially Electroencephalogram (EEG) and Electrocardiogram (ECG), are gaining wide attention as a source of biometric information. Earlier studies have shown that EEG and ECG show versatility with individuals and every individual has distinct EEG and ECG spectrum. EEG (which can be recorded from the scalp due to the effect of millions of neurons) may contain noise signals such as eye blink, eye movement, muscular movement, line noise, etc. Similarly, ECG may contain artifact like line noise, tremor artifacts, baseline wandering, etc. These noise signals are required to be separated from the EEG and ECG signals to obtain the accurate results. This paper proposes a technique for the removal of eye blink artifact from EEG and ECG signal using fixed point or FastICA algorithm of Independent Component Analysis (ICA). For validation, FastICA algorithm has been applied to synthetic signal prepared by adding random noise to the Electrocardiogram (ECG) signal. FastICA algorithm separates the signal into two independent components, i.e. ECG pure and artifact signal. Similarly, the same algorithm has been applied to remove the artifacts (Electrooculogram or eye blink) from the EEG signal.

  11. A general method for cupping artifact correction of cone-beam breast computed tomography images.

    Science.gov (United States)

    Qu, Xiaolei; Lai, Chao-Jen; Zhong, Yuncheng; Yi, Ying; Shaw, Chris C

    2016-07-01

    Cone-beam breast computed tomography (CBBCT), a promising breast cancer diagnostic technique, has been under investigation for the past decade. However, owing to scattered radiation and beam hardening, CT numbers are not uniform on CBBCT images. This is known as cupping artifact, and it presents an obstacle for threshold-based volume segmentation. In this study, we proposed a general post-reconstruction method for cupping artifact correction. There were four steps in the proposed method. First, three types of local region histogram peaks were calculated: adipose peaks with low CT numbers, glandular peaks with high CT numbers, and unidentified peaks. Second, a linear discriminant analysis classifier, which was trained by identified adipose and glandular peaks, was employed to identify the unidentified peaks as adipose or glandular peaks. Third, adipose background signal profile was fitted according to the adipose peaks using the least squares method. Finally, the adipose background signal profile was subtracted from original image to obtain cupping corrected image In experimental study, standard deviation of adipose tissue CT numbers was obviously reduced and the CT numbers were more uniform after cupping correction by proposed method; in simulation study, root-mean-square errors were significantly reduced for both symmetric and asymmetric cupping artifacts, indicating that the proposed method was effective to both artifacts. A general method without a circularly symmetric assumption was proposed to correct cupping artifacts in CBBCT images for breast. It may be properly applied to images of real patient breasts with natural pendent geometry.

  12. Elimination of motion and pulsation artifacts using BLADE sequences in shoulder MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lavdas, E.; Zaloni, E. [Technological Education Institute of Athens, Greece, Department of Medical Radiological Technologists, Athens (Greece); Vlychou, M.; Vassiou, K.; Fezoulidis, I. [University of Thessaly, Department of Radiology, Faculty of Medicine, Larissa (Greece); Tsagkalis, A. [IASO Hospital, Department of Orthopedics, Larissa (Greece); Dailiana, Z. [University of Thessaly, Department of Orthopedics, Faculty of Medicine, Larissa (Greece)

    2015-11-15

    To evaluate the ability of proton-density with fat-suppression BLADE (proprietary name for periodically rotated overlapping parallel lines with enhanced reconstruction in MR systems from Siemens Healthcare, PDFS BLADE) and turbo inversion recovery magnitude-BLADE (TIRM BLADE) sequences to reduce motion and pulsation artifacts in shoulder magnetic resonance examinations. Forty-one consecutive patients who had been routinely scanned for shoulder examination participated in the study. The following pairs of sequences with and without BLADE were compared: (a) Oblique coronal proton-density sequence with fat saturation of 25 patients and (b) oblique sagittal T2 TIRM-weighed sequence of 20 patients. Qualitative analysis was performed by two experienced radiologists. Image motion and pulsation artifacts were also evaluated. In oblique coronal PDFS BLADE sequences, motion artifacts have been significantly eliminated, even in five cases of non-diagnostic value with conventional imaging. Similarly, in oblique sagittal T2 TIRM BLADE sequences, image quality has been improved, even in six cases of non-diagnostic value with conventional imaging. Furthermore, flow artifacts have been improved in more than 80% of all the cases. The use of BLADE sequences is recommended in shoulder imaging, especially in uncooperative patients because it effectively eliminates motion and pulsation artifacts. (orig.)

  13. Dual Adaptive Filtering by Optimal Projection Applied to Filter Muscle Artifacts on EEG and Comparative Study

    Directory of Open Access Journals (Sweden)

    Samuel Boudet

    2014-01-01

    Full Text Available Muscle artifacts constitute one of the major problems in electroencephalogram (EEG examinations, particularly for the diagnosis of epilepsy, where pathological rhythms occur within the same frequency bands as those of artifacts. This paper proposes to use the method dual adaptive filtering by optimal projection (DAFOP to automatically remove artifacts while preserving true cerebral signals. DAFOP is a two-step method. The first step consists in applying the common spatial pattern (CSP method to two frequency windows to identify the slowest components which will be considered as cerebral sources. The two frequency windows are defined by optimizing convolutional filters. The second step consists in using a regression method to reconstruct the signal independently within various frequency windows. This method was evaluated by two neurologists on a selection of 114 pages with muscle artifacts, from 20 clinical recordings of awake and sleeping adults, subject to pathological signals and epileptic seizures. A blind comparison was then conducted with the canonical correlation analysis (CCA method and conventional low-pass filtering at 30 Hz. The filtering rate was 84.3% for muscle artifacts with a 6.4% reduction of cerebral signals even for the fastest waves. DAFOP was found to be significantly more efficient than CCA and 30 Hz filters. The DAFOP method is fast and automatic and can be easily used in clinical EEG recordings.

  14. A Review of Islamic Astronomical Artifacts in Sultan Haji Hassanal Bolkiah Islamic Exhibition Gallery, Brunei Darussalam

    Science.gov (United States)

    Noor, Nor Azam Mat

    2012-09-01

    The study of ancient artifacts is a branch of an ethnographic which includes a socio-cultural community that contributes to the development of civilization. In this case, it can be seen how a community showcase their respective cultures that would have triggered the views and thoughts within their civilization. How culture evolved can be seen from a perspective that although the Persian and Arab neighboring but very different in terms of creativity and their cosmological view. Results demonstrate both artifacts although there are similarities in the symbols of the constellation, but not all in the same cosmos thinking because it is influenced by the myth of the local people. Thus the study of artifacts is to consider the effects of a branch of archaeoastronomy and separate studies that approach on events using celestial navigation apart from the assimilation of science and technology. The study of such artifacts is very important in review of the purpose and scope of the establishment of a gallery and museum as a valuable item such as a heritage and artistic treasures of the world that must be given priority and documenting all the artifacts of which are for aesthetic value.

  15. Body MRI artifacts in clinical practice: a physicist's and radiologist's perspective.

    Science.gov (United States)

    Graves, Martin J; Mitchell, Donald G

    2013-08-01

    The high information content of MRI exams brings with it unintended effects, which we call artifacts. The purpose of this review is to promote understanding of these artifacts, so they can be prevented or properly interpreted to optimize diagnostic effectiveness. We begin by addressing static magnetic field uniformity, which is essential for many techniques, such as fat saturation. Eddy currents, resulting from imperfect gradient pulses, are especially problematic for new techniques that depend on high performance gradient switching. Nonuniformity of the transmit radiofrequency system constitutes another source of artifacts, which are increasingly important as magnetic field strength increases. Defects in the receive portion of the radiofrequency system have become a more complex source of problems as the number of radiofrequency coils, and the sophistication of the analysis of their received signals, has increased. Unwanted signals and noise spikes have many causes, often manifesting as zipper or banding artifacts. These image alterations become particularly severe and complex when they are combined with aliasing effects. Aliasing is one of several phenomena addressed in our final section, on artifacts that derive from encoding the MR signals to produce images, also including those related to parallel imaging, chemical shift, motion, and image subtraction. Copyright © 2013 Wiley Periodicals, Inc.

  16. Artifact removal algorithms for stroke detection using a multistatic MIST beamforming algorithm.

    Science.gov (United States)

    Ricci, E; Di Domenico, S; Cianca, E; Rossi, T

    2015-01-01

    Microwave imaging (MWI) has been recently proved as a promising imaging modality for low-complexity, low-cost and fast brain imaging tools, which could play a fundamental role to efficiently manage emergencies related to stroke and hemorrhages. This paper focuses on the UWB radar imaging approach and in particular on the processing algorithms of the backscattered signals. Assuming the use of the multistatic version of the MIST (Microwave Imaging Space-Time) beamforming algorithm, developed by Hagness et al. for the early detection of breast cancer, the paper proposes and compares two artifact removal algorithms. Artifacts removal is an essential step of any UWB radar imaging system and currently considered artifact removal algorithms have been shown not to be effective in the specific scenario of brain imaging. First of all, the paper proposes modifications of a known artifact removal algorithm. These modifications are shown to be effective to achieve good localization accuracy and lower false positives. However, the main contribution is the proposal of an artifact removal algorithm based on statistical methods, which allows to achieve even better performance but with much lower computational complexity.

  17. An Approach for Multi-Artifact Testing Through an Ontological Perspective for Behavior-Driven Development

    Directory of Open Access Journals (Sweden)

    Thiago Rocha Silva

    2016-07-01

    Full Text Available In a user-centered development process, artifacts evolve in iterative cycles until they meet users’ requirements and then become the final product. Every cycle gives the opportunity to revise the design and to introduce new requirements which might affect the specification of artifacts that have been set in former development phases. Testing the consistency of multiple artifacts used to develop interactive systems every time that new requirements are introduced is a cumbersome activity, especially if it is done manually. This paper proposes an approach based on Behavior-Driven Development (BDD to support the automated assessment of artifacts along the development process of interactive systems. The paper uses an ontology for specifying tests that can run over multiple artifacts sharing similar concepts. A case study testing Task Models, Prototypes, and Final User Interfaces is presented to demonstrate the feasibility of this approach from the early phases of the design process, providing a continuous quality assurance of requirements, and helping clients and development teams to identify potential problems and inconsistencies before commitments with software implementation are made.

  18. Beam Hardening Artifacts: Comparison between Two Cone Beam Computed Tomography Scanners

    Directory of Open Access Journals (Sweden)

    Farzad Esmaeili

    2012-04-01

    Full Text Available Background and aims. At present, cone beam computed tomography (CBCT has become a substitute for computed tomography (CT in dental procedures. The metallic materials used in dentistry can produce artifacts due to the beam hardening phenomenon. These artifacts decrease the quality of images. In the present study, the number of artifacts as a result of beam hardening in the images of dental implants was compared between two NewTom VG and Planmeca Promax 3D Max CBCT machines. Materials and methods. An implant drilling model was used in the present study. The implants (Dentis were placed in the canine, premolar and molar areas. Scanning procedures were carried out by two CBCT machines. The corresponding sections (coronal and axial of the implants were evaluated by two radiologists. The number of artifacts in each image was determined using the scale provided. Mann-Whitney U test was used for two-by-two comparisons at a significance level of P<0.05. Results. There were statistically significant differences in beam hardening artifacts in axial and coronal sections between the two x-ray machines (P<0.001, with a higher quality in the images produced by the NewTom VG. Conclusion. Given the higher quality of the images produced by the NewTom VG x-ray machine, it is recommended for imaging of patients with extensive restorations, multiple prostheses or previous implant treatments.

  19. Automatic Identification of Motion Artifacts in EHG Recording for Robust Analysis of Uterine Contractions

    Directory of Open Access Journals (Sweden)

    Yiyao Ye-Lin

    2014-01-01

    Full Text Available Electrohysterography (EHG is a noninvasive technique for monitoring uterine electrical activity. However, the presence of artifacts in the EHG signal may give rise to erroneous interpretations and make it difficult to extract useful information from these recordings. The aim of this work was to develop an automatic system of segmenting EHG recordings that distinguishes between uterine contractions and artifacts. Firstly, the segmentation is performed using an algorithm that generates the TOCO-like signal derived from the EHG and detects windows with significant changes in amplitude. After that, these segments are classified in two groups: artifacted and nonartifacted signals. To develop a classifier, a total of eleven spectral, temporal, and nonlinear features were calculated from EHG signal windows from 12 women in the first stage of labor that had previously been classified by experts. The combination of characteristics that led to the highest degree of accuracy in detecting artifacts was then determined. The results showed that it is possible to obtain automatic detection of motion artifacts in segmented EHG recordings with a precision of 92.2% using only seven features. The proposed algorithm and classifier together compose a useful tool for analyzing EHG signals and would help to promote clinical applications of this technique.

  20. Automatic identification of motion artifacts in EHG recording for robust analysis of uterine contractions.

    Science.gov (United States)

    Ye-Lin, Yiyao; Garcia-Casado, Javier; Prats-Boluda, Gema; Alberola-Rubio, José; Perales, Alfredo

    2014-01-01

    Electrohysterography (EHG) is a noninvasive technique for monitoring uterine electrical activity. However, the presence of artifacts in the EHG signal may give rise to erroneous interpretations and make it difficult to extract useful information from these recordings. The aim of this work was to develop an automatic system of segmenting EHG recordings that distinguishes between uterine contractions and artifacts. Firstly, the segmentation is performed using an algorithm that generates the TOCO-like signal derived from the EHG and detects windows with significant changes in amplitude. After that, these segments are classified in two groups: artifacted and nonartifacted signals. To develop a classifier, a total of eleven spectral, temporal, and nonlinear features were calculated from EHG signal windows from 12 women in the first stage of labor that had previously been classified by experts. The combination of characteristics that led to the highest degree of accuracy in detecting artifacts was then determined. The results showed that it is possible to obtain automatic detection of motion artifacts in segmented EHG recordings with a precision of 92.2% using only seven features. The proposed algorithm and classifier together compose a useful tool for analyzing EHG signals and would help to promote clinical applications of this technique.

  1. Analysis of metal artifact reduction tools for dental hardware in CT scans of the oral cavity: kVp, iterative reconstruction, dual-energy CT, metal artifact reduction software: does it make a difference?

    Science.gov (United States)

    De Crop, An; Casselman, Jan; Van Hoof, Tom; Dierens, Melissa; Vereecke, Elke; Bossu, Nicolas; Pamplona, Jaime; D'Herde, Katharina; Thierens, Hubert; Bacher, Klaus

    2015-08-01

    Metal artifacts may negatively affect radiologic assessment in the oral cavity. The aim of this study was to evaluate different metal artifact reduction techniques for metal artifacts induced by dental hardware in CT scans of the oral cavity. Clinical image quality was assessed using a Thiel-embalmed cadaver. A Catphan phantom and a polymethylmethacrylate (PMMA) phantom were used to evaluate physical-technical image quality parameters such as artifact area, artifact index (AI), and contrast detail (IQFinv). Metal cylinders were inserted in each phantom to create metal artifacts. CT images of both phantoms and the Thiel-embalmed cadaver were acquired on a multislice CT scanner using 80, 100, 120, and 140 kVp; model-based iterative reconstruction (Veo); and synthesized monochromatic keV images with and without metal artifact reduction software (MARs). Four radiologists assessed the clinical image quality, using an image criteria score (ICS). Significant influence of increasing kVp and the use of Veo was found on clinical image quality (p = 0.007 and p = 0.014, respectively). Application of MARs resulted in a smaller artifact area (p hardware metallic artifacts is not sufficient and may even adversely influence the image quality.

  2. Faculty and medical student attitudes about preclinical classroom attendance.

    Science.gov (United States)

    Zazulia, Allyson R; Goldhoff, Patricia

    2014-01-01

    Technological advances have diminished reliance on classroom attendance for mastering preclinical medical school course content, but nonattendance may have unintended consequence on the learning environment. Perceptions among educators and students regarding the value of attendance and implications of nonattendance have not been systematically studied. The purpose of this study was to investigate differences in medical student and faculty attitudes regarding preclinical classroom attendance and the impact of nonattendance on educators and the learning environment. Using Internet-based surveys, we assessed attitudes about preclinical classroom attendance among medical students and teaching faculty at Washington University School of Medicine. Our primary hypothesis was that students would be less likely than faculty to place societal value on attendance and relate it to professionalism. A total of 382 (79%) of 484 eligible students and 248 (64%) of 387 eligible faculty completed the survey. Both groups recognized a negative impact of poor attendance on faculty enthusiasm for teaching (students 83%, faculty 75%), but faculty were significantly more likely to endorse a negative impact on effectiveness of lectures (75% vs. 42%, pclass for research and community service activities (70% vs. 14%, pclass-going primarily as a tool for learning factual material, whereas many faculty viewed it as serving important functions in the professional socialization process. In this single-center cohort, medical student and teaching faculty attitudes differed regarding the importance of classroom attendance and its relationship to professionalism, findings that were at least partially explained by differing expectations of the purpose of the preclinical classroom experience.

  3. The Bird Box Survey Project

    Science.gov (United States)

    Willis, Patrick

    2014-01-01

    When high school students are asked what's the best part of science class, many will say it's the field trips. Students enjoy engaging in authentic, community-based science outside the classroom. To capitalize on this, Patrick Willis created the Bird Box Survey Project for his introductory field biology class. The project takes students…

  4. Reduction of variable-truncation artifacts from beam occlusion during in situ x-ray tomography

    DEFF Research Database (Denmark)

    Borg, Leise; Jørgensen, Jakob Sauer; Frikel, Jürgen

    2017-01-01

    Many in situ x-ray tomography studies require experimental rigs which may partially occlude the beam and cause parts of the projection data to be missing. In a study of fluid flow in porous chalk using a percolation cell with four metal bars drastic streak artifacts arise in the filtered...... discontinuities that are shown to be the source of the streaks. The ‘reduction to limited angle’ (RLA) method simply keeps only non-truncated projections; the ‘detector-directed smoothing’ (DDS) method smooths the discontinuities; while the ‘reflexive boundary condition’ (RBC) method enforces a zero derivative...... at the discontinuities. Experimental results using both simulated and real data show that the proposed methods effectively reduce variable-truncation artifacts. The RBC method is found to provide the best artifact reduction and preservation of image features using both visual and quantitative assessment. The analysis...

  5. Automatic detection and classification of artifacts in single-channel EEG

    DEFF Research Database (Denmark)

    Olund, Thomas; Duun-Henriksen, Jonas; Kjaer, Troels W.

    2014-01-01

    Ambulatory EEG monitoring can provide medical doctors important diagnostic information, without hospitalizing the patient. These recordings are however more exposed to noise and artifacts compared to clinically recorded EEG. An automatic artifact detection and classification algorithm for single......-channel EEG is proposed to help identifying these artifacts. Features are extracted from the EEG signal and wavelet subbands. Subsequently a selection algorithm is applied in order to identify the best discriminating features. A non-linear support vector machine is used to discriminate among different....... The detection algorithm yield an average sensitivity and specificity above 95% for both the subject-specific and generic models. The classification algorithm show a mean accuracy of 78 and 64% for the subject-specific and generic model, respectively. The classification model was additionally validated...

  6. Removal of muscle artifacts from EEG recordings of spoken language production.

    Science.gov (United States)

    De Vos, Maarten; Vos, De Maarten; Riès, Stephanie; Vanderperren, Katrien; Vanrumste, Bart; Alario, Francois-Xavier; Van Huffel, Sabine; Huffel, Van Sabine; Burle, Boris

    2010-06-01

    Research on the neural basis of language processing has often avoided investigating spoken language production by fear of the electromyographic (EMG) artifacts that articulation induces on the electro-encephalogram (EEG) signal. Indeed, such articulation artifacts are typically much larger than the brain signal of interest. Recently, a Blind Source Separation technique based on Canonical Correlation Analysis was proposed to separate tonic muscle artifacts from continuous EEG recordings in epilepsy. In this paper, we show how the same algorithm can be adapted to remove the short EMG bursts due to articulation on every trial. Several analyses indicate that this method accurately attenuates the muscle contamination on the EEG recordings, providing to the neurolinguistic community a powerful tool to investigate the brain processes at play during overt language production.

  7. Effect of motion artifact on digital camera based heart rate measurement.

    Science.gov (United States)

    Hassan, M A; Malik, A S; Saad, N; Fofi, D; Meriaudeau, F

    2017-07-01

    Remote health monitoring is an emerging field in biomedical technology. Digital camera based heart rate measurement method is a recent development which would make remote health monitoring reliable and sustainable in future. This paper presents an investigation on the effect of motion artifact on digital camera-based heart rate measurement. The paper will discuss details on the principles and effects of motion artifacts on photoplethysmography signals. An experiment is conducted using publicly available MAHNOB-HCI database. We have investigated the effects of static scenarios, scenarios involving rigid motion and scenarios involving non-rigid motion. The experiment was tested on state of the art digital camera based heart rate measuring methods. The results showed the effectiveness of the methods and provide a direction to overcome/minimize the effect of motion artifacts for future research.

  8. Fuzzy entropy based motion artifact detection and pulse rate estimation for fingertip photoplethysmography.

    Science.gov (United States)

    Paradkar, Neeraj; Chowdhury, Shubhajit Roy

    2014-01-01

    The paper presents a fingertip photoplethysmography (PPG) based technique to estimate the pulse rate of the subject. The PPG signal obtained from a pulse oximeter is used for the analysis. The input samples are corrupted with motion artifacts due to minor motion of the subjects. Entropy measure of the input samples is used to detect the motion artifacts and estimate the pulse rate. A three step methodology is adapted to identify and classify signal peaks as true systolic peaks or artifact. CapnoBase database and CSL Benchmark database are used to analyze the technique and pulse rate estimation was performed with positive predictive value and sensitivity figures of 99.84% and 99.32% respectively for CapnoBase and 98.83% and 98.84% for CSL database respectively.

  9. Metal artifact reduction in CT by identifying missing data hidden in metals.

    Science.gov (United States)

    Park, Hyoung Suk; Choi, Jae Kyu; Park, Kyung-Ran; Kim, Kyung Sang; Lee, Sang-Hwy; Ye, Jong Chul; Seo, Jin Keun

    2013-01-01

    There is increasing demand in the field of dental and medical radiography for effective metal artifact reduction (MAR) in computed tomography (CT) because artifact caused by metallic objects causes serious image degradation that obscures information regarding the teeth and/or other biological structures. This paper presents a new MAR method that uses the Laplacian operator to reveal background projection data hidden in regions containing data from metal. In the proposed method, we attempted to decompose the projection data into two parts: data from metal only (metal data), and background data in the absence of metal. Removing metal data from the projections enables us to perform sparsity-driven reconstruction of the metal component and subsequent removal of the metal artifact. The results of clinical experiments demonstrated that the proposed MAR algorithm improves image quality and increases the standard of 3D reconstruction images of the teeth and mandible.

  10. Flexible Method for the Automated Offline-Detection of Artifacts in Multi-Channel Electroencephalogram Recordings

    DEFF Research Database (Denmark)

    Waser, Markus; Garn, Heinrich; Benke, Thomas

    2017-01-01

    . However, these preprocessing steps do not allow for complete artifact correction. We propose a method for the automated offline-detection of remaining artifacts after preprocessing in multi-channel EEG recordings. In contrast to existing methods it requires neither adaptive parameters varying between...... recordings nor a topography template. It is suited for short EEG segments and is flexible with regard to target applications. The algorithm was developed and tested on 60 clinical EEG samples of 20 seconds each that were recorded both in resting state and during cognitive activation to gain a realistic...... artifact set. Five EEG features were used to quantify temporal and spatial signal variations. Two distance measures for the single-channel and multi-channel variations of these features were defined. The global thresholds were determined by three-fold cross-validation and Youden's J statistic...

  11. Industrial Experiences with a Formal DSL Semantics to Check the Correctness of DSL Artifacts

    Directory of Open Access Journals (Sweden)

    Sarmen Keshishzadeh

    2016-03-01

    Full Text Available A domain specific language (DSL abstracts from implementation details and is aligned with the way domain experts reason about a software component. The development of DSLs is usually centered around a grammar and transformations that generate implementation code or analysis models. The semantics of the language is often defined implicitly and in terms of a transformation to implementation code. In the presence of multiple transformations from the DSL, the correctness of the generated artifacts with respect to the semantics of the DSL is a relevant issue. We show that a formal semantics is essential for checking the correctness of the generated artifacts. We exploit the formal semantics in an industrial project and use formal techniques based on equivalence checking and model-based testing for validating the correctness of the generated artifacts. We report about our experience with this approach in an industrial development project.

  12. Automated motion artifact removal for intravital microscopy, without a priori information

    Science.gov (United States)

    Lee, Sungon; Vinegoni, Claudio; Sebas, Matthew; Weissleder, Ralph

    2014-03-01

    Intravital fluorescence microscopy, through extended penetration depth and imaging resolution, provides the ability to image at cellular and subcellular resolution in live animals, presenting an opportunity for new insights into in vivo biology. Unfortunately, physiological induced motion components due to respiration and cardiac activity are major sources of image artifacts and impose severe limitations on the effective imaging resolution that can be ultimately achieved in vivo. Here we present a novel imaging methodology capable of automatically removing motion artifacts during intravital microscopy imaging of organs and orthotopic tumors. The method is universally applicable to different laser scanning modalities including confocal and multiphoton microscopy, and offers artifact free reconstructions independent of the physiological motion source and imaged organ. The methodology, which is based on raw data acquisition followed by image processing, is here demonstrated for both cardiac and respiratory motion compensation in mice heart, kidney, liver, pancreas and dorsal window chamber.

  13. A PRACTICAL ONTOLOGY FOR THE LARGE-SCALE MODELING OF SCHOLARLY ARTIFACTS AND THEIR USAGE

    Energy Technology Data Exchange (ETDEWEB)

    RODRIGUEZ, MARKO A. [Los Alamos National Laboratory; BOLLEN, JOHAN [Los Alamos National Laboratory; VAN DE SOMPEL, HERBERT [Los Alamos National Laboratory

    2007-01-30

    The large-scale analysis of scholarly artifact usage is constrained primarily by current practices in usage data archiving, privacy issues concerned with the dissemination of usage data, and the lack of a practical ontology for modeling the usage domain. As a remedy to the third constraint, this article presents a scholarly ontology that was engineered to represent those classes for which large-scale bibliographic and usage data exists, supports usage research, and whose instantiation is scalable to the order of 50 million articles along with their associated artifacts (e.g. authors and journals) and an accompanying 1 billion usage events. The real world instantiation of the presented abstract ontology is a semantic network model of the scholarly community which lends the scholarly process to statistical analysis and computational support. They present the ontology, discuss its instantiation, and provide some example inference rules for calculating various scholarly artifact metrics.

  14. Artifact reduction in multichannel pervasive EEG using hybrid WPT-ICA and WPT-EMD signal decomposition techniques

    CERN Document Server

    Bono, Valentina; Das, Saptarshi; Maharatna, Koushik

    2014-01-01

    In order to reduce the muscle artifacts in multi-channel pervasive Electroencephalogram (EEG) signals, we here propose and compare two hybrid algorithms by combining the concept of wavelet packet transform (WPT), empirical mode decomposition (EMD) and Independent Component Analysis (ICA). The signal cleaning performances of WPT-EMD and WPT-ICA algorithms have been compared using a signal-to-noise ratio (SNR)-like criterion for artifacts. The algorithms have been tested on multiple trials of four different artifact cases viz. eye-blinking and muscle artifacts including left and right hand movement and head-shaking.

  15. ECG artifact cancellation in surface EMG signals by fractional order calculus application.

    Science.gov (United States)

    Miljković, Nadica; Popović, Nenad; Djordjević, Olivera; Konstantinović, Ljubica; Šekara, Tomislav B

    2017-03-01

    New aspects for automatic electrocardiography artifact removal from surface electromyography signals by application of fractional order calculus in combination with linear and nonlinear moving window filters are explored. Surface electromyography recordings of skeletal trunk muscles are commonly contaminated with spike shaped artifacts. This artifact originates from electrical heart activity, recorded by electrocardiography, commonly present in the surface electromyography signals recorded in heart proximity. For appropriate assessment of neuromuscular changes by means of surface electromyography, application of a proper filtering technique of electrocardiography artifact is crucial. A novel method for automatic artifact cancellation in surface electromyography signals by applying fractional order calculus and nonlinear median filter is introduced. The proposed method is compared with the linear moving average filter, with and without prior application of fractional order calculus. 3D graphs for assessment of window lengths of the filters, crest factors, root mean square differences, and fractional calculus orders (called WFC and WRC graphs) have been introduced. For an appropriate quantitative filtering evaluation, the synthetic electrocardiography signal and analogous semi-synthetic dataset have been generated. The examples of noise removal in 10 able-bodied subjects and in one patient with muscle dystrophy are presented for qualitative analysis. The crest factors, correlation coefficients, and root mean square differences of the recorded and semi-synthetic electromyography datasets showed that the most successful method was the median filter in combination with fractional order calculus of the order 0.9. Statistically more significant (p < 0.001) ECG peak reduction was obtained by the median filter application compared to the moving average filter in the cases of low level amplitude of muscle contraction compared to ECG spikes. The presented results suggest

  16. Language and other artifacts: socio-cultural dynamics of niche construction

    Science.gov (United States)

    Sinha, Chris

    2015-01-01

    Niche construction theory is a relatively new approach in evolutionary biology that seeks to integrate an ecological dimension into the Darwinian theory of evolution by natural selection. It is regarded by many evolutionary biologists as providing a significant revision of the Neo-Darwinian modern synthesis that unified Darwin’s theory of natural and sexual selection with 20th century population genetics. Niche construction theory has been invoked as a processual mediator of social cognitive evolution and of the emergence and evolution of language. I argue that language itself can be considered as a biocultural niche and evolutionary artifact. I provide both a general analysis of the cognitive and semiotic status of artifacts, and a formal analysis of language as a social and semiotic institution, based upon a distinction between the fundamental semiotic relations of “counting as” and “standing for.” I explore the consequences for theories of language and language learning of viewing language as a biocultural niche. I suggest that not only do niches mediate organism-organism interactions, but also that organisms mediate niche-niche interactions in ways that affect evolutionary processes, with the evolution of human infancy and childhood as a key example. I argue that language as a social and semiotic system is not only grounded in embodied engagements with the material and social-interactional world, but also grounds a sub-class of artifacts of particular significance in the cultural history of human cognition. Symbolic cognitive artifacts materially and semiotically mediate human cognition, and are not merely informational repositories, but co-agentively constitutive of culturally and historically emergent cognitive domains. I provide examples of the constitutive cognitive role of symbolic cognitive artifacts drawn from my research with my colleagues on cultural and linguistic conceptualizations of time, and their cultural variability. I conclude by

  17. The emergence of semantic categorization in early visual processing: ERP indices of animal vs. artifact recognition

    Directory of Open Access Journals (Sweden)

    Del Zotto Marzia

    2007-04-01

    Full Text Available Abstract Background Neuroimaging and neuropsychological literature show functional dissociations in brain activity during processing of stimuli belonging to different semantic categories (e.g., animals, tools, faces, places, but little information is available about the time course of object perceptual categorization. The aim of the study was to provide information about the timing of processing stimuli from different semantic domains, without using verbal or naming paradigms, in order to observe the emergence of non-linguistic conceptual knowledge in the ventral stream visual pathway. Event related potentials (ERPs were recorded in 18 healthy right-handed individuals as they performed a perceptual categorization task on 672 pairs of images of animals and man-made objects (i.e., artifacts. Results Behavioral responses to animal stimuli were ~50 ms faster and more accurate than those to artifacts. At early processing stages (120–180 ms the right occipital-temporal cortex was more activated in response to animals than to artifacts as indexed by posterior N1 response, while frontal/central N1 (130–160 showed the opposite pattern. In the next processing stage (200–260 the response was stronger to artifacts and usable items at anterior temporal sites. The P300 component was smaller, and the central/parietal N400 component was larger to artifacts than to animals. Conclusion The effect of animal and artifact categorization emerged at ~150 ms over the right occipital-temporal area as a stronger response of the ventral stream to animate, homomorphic, entities with faces and legs. The larger frontal/central N1 and the subsequent temporal activation for inanimate objects might reflect the prevalence of a functional rather than perceptual representation of manipulable tools compared to animals. Late ERP effects might reflect semantic integration and cognitive updating processes. Overall, the data are compatible with a modality-specific semantic memory

  18. Language and other artifacts: socio-cultural dynamics of niche construction.

    Science.gov (United States)

    Sinha, Chris

    2015-01-01

    Niche construction theory is a relatively new approach in evolutionary biology that seeks to integrate an ecological dimension into the Darwinian theory of evolution by natural selection. It is regarded by many evolutionary biologists as providing a significant revision of the Neo-Darwinian modern synthesis that unified Darwin's theory of natural and sexual selection with 20th century population genetics. Niche construction theory has been invoked as a processual mediator of social cognitive evolution and of the emergence and evolution of language. I argue that language itself can be considered as a biocultural niche and evolutionary artifact. I provide both a general analysis of the cognitive and semiotic status of artifacts, and a formal analysis of language as a social and semiotic institution, based upon a distinction between the fundamental semiotic relations of "counting as" and "standing for." I explore the consequences for theories of language and language learning of viewing language as a biocultural niche. I suggest that not only do niches mediate organism-organism interactions, but also that organisms mediate niche-niche interactions in ways that affect evolutionary processes, with the evolution of human infancy and childhood as a key example. I argue that language as a social and semiotic system is not only grounded in embodied engagements with the material and social-interactional world, but also grounds a sub-class of artifacts of particular significance in the cultural history of human cognition. Symbolic cognitive artifacts materially and semiotically mediate human cognition, and are not merely informational repositories, but co-agentively constitutive of culturally and historically emergent cognitive domains. I provide examples of the constitutive cognitive role of symbolic cognitive artifacts drawn from my research with my colleagues on cultural and linguistic conceptualizations of time, and their cultural variability. I conclude by reflecting on

  19. SU-F-T-407: Artifact Reduction with Dual Energy Or IMAR: Who’s Winning?

    Energy Technology Data Exchange (ETDEWEB)

    Elder, E; Schreibmann, E; Dhabaan, A [Department of Radiation Oncology and Winship Cancer Institute of Emory University Atlanta, GA (United States)

    2016-06-15

    Purpose: The purpose of this abstract was to evaluate the performance of commercial strategies for artifact reduction in radiation oncology settings. The iterative metal artifact reduction (Siemens iMAR) algorithm and monoenergetic virtual datasets reconstructed from dual energy scans are compared side-by-side in their ability to image in the presence of metal inserts. Methods: A CIRS ATOM Dosimetry Verification Phantom was scanned with and without a metal insert on a SOMATOM Definition AS dual energy scanner. Images with the metal insert were reconstructed with (a) a tradition single energy CT scan with the iMAR option implemented, using different artifact reduction settings and (b) a monoenergetic scan calculated from dual energy scans by recovering differences in the energy-dependence of the attenuation coefficients of different materials and then creating a virtual monoenergetic scan from these coefficients. The iMAR and monoenergetic scans were then compared with the metal-free scan to assess changes in HU numbers and noise within a region around the metal insert. Results: Both the iMAR and dual energy scans reduced artifacts produced by the metal insert. However the iMAR results are dependent of the selected algorithm settings, with a mean HU difference ranging from 0.65 to 90.40 for different options. The mean differences without the iMAR correction were 38.74. When using the dual energy scan, the mean differences were 4.53, that is however attributed to increased noise and not artifacts, as the dual energy scan had the lowest skewness (2.52) compared to the iMAR scans (ranging from 3.90 to 4.88) and the lowest kurtosis (5.72 for dual energy, range of 18.19 to 27.36 for iMAR). Conclusion: Both approaches accurately recovered HU numbers, however the dual energy method provided smaller residual artifacts.

  20. Artifact reduction of compressed images and video combining adaptive fuzzy filtering and directional anisotropic diffusion

    DEFF Research Database (Denmark)

    Nadernejad, Ehsan; Forchhammer, Søren; Korhonen, Jari

    2011-01-01

    and ringing artifacts, we have applied directional anisotropic diffusion. Besides that, the selection of the adaptive threshold parameter for the diffusion coefficient has also improved the performance of the algorithm. Experimental results on JPEG compressed images as well as MJPEG and H.264 compressed......Fuzzy filtering is one of the recently developed methods for reducing distortion in compressed images and video. In this paper, we combine the powerful anisotropic diffusion equations with fuzzy filtering in order to reduce the impact of artifacts. Based on the directional nature of the blocking...