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891.
In this paper, we address the problem of tracking DOA of multiple moving targets with known signal source waveforms and unknown gains in the presence of Gaussian noise using a nonuniform linear array. Herein, we make use of the fact that the output of each sensor can be described as a linear regression model whose coefficients each contain a pair of DOA and gain information corresponding to one target. These coefficients are determined by solving a linear least squares (LS) problem and then updated recursively based on a block QR decomposition recursive least squares (QRD-RLS) technique or a block regularized LS technique. Since the coefficients from different sensors have the same amplitude but variable phase information for the same signal, along with simple algebraic manipulations the well-known generalized least squares (GLS) are used to obtain an asymptotically-optimal DOA estimate without requiring a search over a large region of the parameter space. Computer simulations show that the proposed DOA tracking techniques when applied to a sparse antenna array can provide a better tracking performance than some of the existing methods do. 相似文献
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N.S. Heineken 《Journal of The Franklin Institute》1838,25(3):192-193
895.
N B Guterman 《Child abuse & neglect》1999,23(9):863-890
OBJECTIVE: Seeking to discern optimal programmatic strategies and inform the "universal versus targeted" debate in early home visitation services to prevent physical child abuse and neglect, a meta-analysis was conducted examining enrollment approaches in early home visitation studies and their reported outcomes. METHOD: Quantitative meta-analytic techniques were used to compare effect sizes from 19 controlled outcome studies across screening-based and population-based enrollment strategies. Effect sizes were calculated on protective services data and on child maltreatment related measures of parenting. RESULTS: On protective services report data, population-based studies reported a weighted mean effect size attributable to early home visitation of +3.72%, in comparison to -.07% for screening-based studies. On child maltreatment related measures of parenting, population-based studies reported a weighted mean effect size (r) attributable to early home visitation of +.092, in comparison to +.020 for screening-based studies. CONCLUSIONS: The findings indicate that population-based enrollment strategies appear favorable to screening-based ones in early home visitation programs seeking to prevent physical child abuse and neglect. It may be that psychosocial risk screens serve to enroll higher proportions of families for which early home visitation services are less likely to leverage change, and to exacerbate a mismatch between early home visitation service aims and family needs. 相似文献
896.
N. Chandra Shekhar K. Venkatasubbaiah N. R. Kandukuria 《European Journal of Engineering Education》2012,37(6):575-591
Measuring overall service quality (OSQ) is gaining prominence in higher education due to the increased competition among engineering education institutions (EEIs) and growing awareness about value for money among the public. Determination of OSQ on certain institutional aspects is done by various agencies throughout the world. Each system uses a different set of weighted indicators to measure the overall service quality of institutions. Five service quality factors, namely professionalism, integrated education, facilities, responsiveness and empathy are considered in the study. Trapezoidal fuzzy numbers are used to determine the aggregate weights of the factors to handle the vagueness present in the linguistic values of the stakeholders’ subjective opinions. Final weights of the factors are assessed by taking the distances of each factor between Fuzzy Positive Ideal Rating and Fuzzy Negative Ideal Rating. An illustrative study is presented to determine the OSQ of EEIs. The results help to focus on the factors which need immediate attention to enhance the quality of EEIs. 相似文献
897.
Amanda O. Latz James N. Rediger 《Community College Journal of Research & Practice》2014,38(2-3):280-285
Generational and life course theory lenses were placed upon one finding of a large-scale qualitative interview-based study focused on if and how community college faculty members construct work–life balance. Twenty-eight interviews with faculty members at a midwestern community college were conducted. Differences regarding to work-life balance approaches between Baby Boomer (n = 15) and Generation X (n = 13) faculty and as mediated by position within the life course are elucidated. We termed this finding tides of life, which is comprised of three subfindings: roles, tenure, and gender performance. Practical implications of this finding are put forward. Better understanding of the nuanced ways in which community college faculty construct work–life balance can inform policy decisions that impact faculty work. Moreover, better understanding of faculty life in a general sense is critical as community college leaders craft policies and refine practices related to faculty employment contracts, work environments, support mechanisms, professional development, and mentoring. 相似文献
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N. Valanides F. Gritsi M. Kampeza K. Ravanis 《International Journal of Early Years Education》2000,8(1):27-39
A semi-structured interview was individually administered to 33 children aged 5-6. The interview raised questions about the shapes of the Sun and the Earth as well as the cause of the day/night cycle. A teaching intervention designed to teach pre-school age children these concepts was then implemented with groups of 6-7 children. The intervention's effectiveness was consequently evaluated (after 2 weeks) using an interview similar to that conducted prior to the intervention. The results of the study showed that the majority of children readily accepted certain aspects of the scientific explanations of the day/night cycle. Specifically, the majority accepted that the Sun and the Earth are separate spherical objects, but fewer children attributed the day/night cycle to rotation of the Earth on its axis. Most seemed puzzled by the simultaneous movements of the Earth around the Sun and around its axis. Educational and research implications are discussed. Une semi-directive interview individuelle etait administree a 33 enfants de 5 a 6 ans. L'interview contenait des questions sur le scheme du soleil et de la terre et aussi sur la cause du cercle 'jour-nuit'. Une intervention didactique etait apres introduite aux groups de 6-7 enfants et ses resultats etaient finalement evalues, en utilisant la meme interview, deux semaines apres l'intervention. Les resultats de cet etude montrent que la majorite d'enfants ont accepte certains aspects des points de vue scientifiques concernant le cercle 'jour-nuit'. Plus specifiquement, la plupart d'enfants ont accepte que les schemes du soleil et de la terre ressemblaient a une sphere, mais moins d'enfants ont attribue le cercle 'jour-nuit' a la rotation de la terre autour du soi-meme. Quelques enfants n'ont pas developpe les correctes conceptions et c'etait apparent qu'ils avaient des difficultes a comprendre les mouvements simultanes de la terre autour du soleil et du soi-meme. Se administro individualmente una entrevista semiestructurada a 33 ninos de edades comprendidas entre los 5 y 6 anos. La entrevista incluja cuestiones sobre formas del sol y de la tierra y tambien la causa del ciclo dia/noche. Luego se introdujo una intervencion didactica a grupos de 6-7 ninos de edad preescolar para ensenarles estos conceptos. La efectividad de la intervencion file evaluada 2 semanas mas tarde, con una entrevista parecida a la realizada antes de la intervencion. Los resultados del estudjo mostraron que la mayoria de los ninos aceptaban facilmente ciertos aspectos de las explicaciones cientificas del ciclo dia/noche. Mas especialmente, la mayoria aceptaba que el sol y la tierra eran objetos esfericos diferentes, pero menos ninos atribuian el hecho de que el ciclo dia/noche se relacionara con la rotacion de la tierra alrededor de sil eje. Muchos parecian sorprenderse con los movimientos simultaneos de la tierra alrededor del sol y alrededor de si misma. Se discuten las implicaciones educativas y de investigacion. 相似文献