978 resultados para Computer arithmetic and logic units


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An important goal in computational neuroanatomy is the complete and accurate simulation of neuronal morphology. We are developing computational tools to model three-dimensional dendritic structures based on sets of stochastic rules. This paper reports an extensive, quantitative anatomical characterization of simulated motoneurons and Purkinje cells. We used several local and global algorithms implemented in the L-Neuron and ArborVitae programs to generate sets of virtual neurons. Parameters statistics for all algorithms were measured from experimental data, thus providing a compact and consistent description of these morphological classes. We compared the emergent anatomical features of each group of virtual neurons with those of the experimental database in order to gain insights on the plausibility of the model assumptions, potential improvements to the algorithms, and non-trivial relations among morphological parameters. Algorithms mainly based on local constraints (e.g., branch diameter) were successful in reproducing many morphological properties of both motoneurons and Purkinje cells (e.g. total length, asymmetry, number of bifurcations). The addition of global constraints (e.g., trophic factors) improved the angle-dependent emergent characteristics (average Euclidean distance from the soma to the dendritic terminations, dendritic spread). Virtual neurons systematically displayed greater anatomical variability than real cells, suggesting the need for additional constraints in the models. For several emergent anatomical properties, a specific algorithm reproduced the experimental statistics better than the others did. However, relative performances were often reversed for different anatomical properties and/or morphological classes. Thus, combining the strengths of alternative generative models could lead to comprehensive algorithms for the complete and accurate simulation of dendritic morphology.

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Optical characteristics of stirred curd were simultaneously monitored during syneresis in a 10-L cheese vat using computer vision and colorimetric measurements. Curd syneresis kinetic conditions were varied using 2 levels of milk pH (6.0 and 6.5) and 2 agitation speeds (12.1 and 27.2 rpm). Measured optical parameters were compared with gravimetric measurements of syneresis, taken simultaneously. The results showed that computer vision and colorimeter measurements have potential for monitoring syneresis. The 2 different phases, curd and whey, were distinguished by means of color differences. As syneresis progressed, the backscattered light became increasingly yellow in hue for circa 20 min for the higher stirring speed and circa 30 min for the lower stirring speed. Syneresis-related gravimetric measurements of importance to cheese making (e.g., curd moisture content, total solids in whey, and yield of whey) correlated significantly with computer vision and colorimetric measurements..

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Fluorene and thiophene units are commonly used in polymeric materials for electro-optical applications. Due to differences in reactivity, the final composition of polymers containing these components often differs from that used in their preparation. This contribution describes the synthesis of PPV type terpolymers built by fluorene, phenylene and thiophene units and their quantification by CPMAS NMR. The similarity of the three aromatic co-monomers makes it difficult to separate the analytical responses that would allow quantification of each copolymer unit in the chain. In this sense, we show that the combination of dipolar dephased CPMAS with radiofrequency ramp and proper spectral treatment allows a good estimation and quantification of the copolymer constitution. (C) 2011 Elsevier Ltd. All rights reserved.

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Background: Constructive alignment (CA) is a pedagogical approach that emphasizes the alignment between the intended learning outcomes (ILOs), teaching and learning activities (TLAs) and assessment tasks (ATs) as well as creation of a teaching/learning environment where students will be able to actively create their knowledge. Objectives: This paper aims at investigating the extent of constructively-aligned courses in Computer Engineering and Informatics department at Dalarna University, Sweden. This study is based on empirical observations of teacher’s perceptions of implementation of CA in their courses. Methods: Ten teachers (5 from each department) were asked to fill a paper-based questionnaire, which included a number of questions related to issues of implementing CA in courses. Results: Responses to the items of the questionnaire were mixed. Teachers clearly state the ILOs in their courses and try to align the TLAs and ATs to the ILOs. Computer Engineering teachers do not explicitly communicate the ILOs to the students as compared to Informatics teachers. In addition, Computer Engineering teachers stated that their students are less active in learning activities as compared to Informatics teachers. When asked about their subjective ratings of teaching methods all teachers stated that their current teaching is teacher-centered but they try to shift the focus of activity from them to the students. Conclusions: From teachers’ perspectives, the courses are partially constructively-aligned. Their courses are “aligned”, i.e. ILOs, TLAs and ATs are aligned to each other but they are not “constructive” since, according to them, there was a low student engagement in learning activities, especially in Computer Engineering department.

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The recent High Court decision in Macleod v R establishes that a director and sole shareholder may be convicted of fraudulently applying a company's property even though the person has consented to the personal use of the company's property. It is contended that while this decision is consistent with the weight of precedent, it is wrong in principle. The decision implies that corporations are not only separate legal entities, but that they are highly virtuous legal entities -- incapable of being imbued with the dishonest intentions and activities of the individuals controlling the company.

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There is recognition that the first-year of university study is a critical phase in the preparation, motivation and retention of science, mathematics,  engineering and technology (SMET) students. First-year provides the foundation/generic skills upon which students will base their undergraduate studies and professional practice; first-year is where many poorly prepared/at risk students will drop out and contribute to the poor student retention rate observed in the SMET disciplines; and first-year is when students may lose the motivation to pursue their chosen career direction if they find the studies at the commencement of their undergraduate program appear to bear no relationship to their intended career. In 2003, the Learning Resources Advisory Group of the Deakin University School of Engineering and Technology was requested to undertake a review of first-year units in the School’s programs. The information contained in anonymous unit evaluation questionnaires from the years 2000-2002 was used as the basis for analysing student perceptions of first-year units. In unit evaluations, students reported a wide range of issues that impacted negatively on their perception of the content and conduct of first-year units. It was noted that units service taught by other Schools form a significant element of the first-year of all of the Engineering and Technology undergraduate programs – typically 25 to 50 percent of the content. The significant influence of these units on the perceptions of the first-year of the School’s commencing students means that the School should exercise some control over the content and delivery of these units.

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Objective: To investigate relationships between children's body mass index (BMI) and parent reports of children's television and video game/computer habits, controlling for other potential risk factors for paediatric obesity.

Methods: Child BMI was calculated from measured height and weight collected in 1997 as part of a large, representative, cross-sectional study of children in Victoria, Australia. Parents reported the amount of time children watched television and used video games/computers, children's eating and activity habits, parental BMI and sociodemographic details.

Results: A total of 2862 children aged 5−13 years participated. Child mean BMI z-score was significantly related to television (F = 10.23, P < 0.001) but not video game/computer time (F = 2.23, P = 0.09), but accounted for only 1 and 0.2% of total BMI variance, respectively. When parental BMI, parental education, number of siblings, food intake, organized exercise and general activity level were included, television ceased to be independently significantly related to child BMI. Using adjusted logistic regression, the odds of being overweight and obese generally increased with increasing television viewing. No relationship was found for video game/computer use.
Conclusions: A small proportion of variance in child BMI was related to television, but not video game/computer time. This was far outweighed by the influence of other variables. Causal pathways are likely to be complex and interrelated.

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Course websites have become a basic requirement for course promotion and delivery in many universities. This study explores the relationship between perceived usefulness of course websites and student performance in an accounting course within a Masters of Business Administration (MBA) programme. Data from 48 students were found to support several hypotheses. Specifically, the findings of the study indicate that there is a significant correlation between the perceived usefulness of course website features such as lecture notes, tutorial questions and solutions and the frequency of use or access by students of such course website features. Further, we found that the perceived usefulness of course websites was positively related to students’ computer proficiency, but not with the frequency with which students missed classes. The findings also indicate that students with high need for achievement achieved better performance scores, but there was no significant relationship between perceived usefulness of course website and performance. These findings have several implications for the design and development of course websites at post-graduate level, and for future research examining the link between information technology and accounting education.

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This thesis aims to analyse the needs of museums in terms of computer databases, examine the ways in which these databases can assist with cataloguing and museum operations in general, and survey current database programs available. The Jewish Museum of Australia is used as a pilot study to practically apply the issues discussed.

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As the new millennium approaches, we are living in a society that is increasingly dependent upon information technology. However, whilst technology can deliver a number of benefits, it also introduces new vulnerabilities that can be exploited by persons with the necessary technical skills. Hackers represent a well-known threat in this respect and are responsible for a significant degree of disruption and damage to information systems. However, they are not the only criminal element that has to be taken into consideration. Evidence suggests that technology is increasingly seen as potential tool for terrorist organizations. This is leading to the emergence of a new threat in the form of 'cyber terrorists', who attack technological infrastructures such as the Internet in order to help further their cause. The paper discusses the problems posed by these groups and considers the nature of the responses necessary to preserve the future security of our society.