326 research outputs found
The economic and accounting content of fixed assets
This book presents a mathematical methodology for image analysis tasks at the edge of current research, including anisotropic diffusion filtering of tensor fields. Instead of specific applications, it explores methodological structures on which they are built.DIPLECS, GARNICS, NACI
Imaging in Acute Stroke
Imaging in the acute setting of suspected stroke is an important topic to all emergency physicians, neurologists, neurosurgeons and neuroradiologist. When it comes to imaging, the American College of Radiology (ACR) continually updates its guidelines for imaging pathways through the ACR Appropriateness Criteria.1,2 This article is a general review of the imaging modalities currently used to assess and help guide the treatment of strokes
Improving the achievements of non-traditional students on computing courses at one wide access university
This longitudinal study set out to improve the retention and achievements of diverse students on computing courses in one wide access university, firstly by early identification of students at risk of poor performance and secondly by developing and implementing an intervention programme. Qualitative data were obtained using the ASSIST questionnaire, by focus group discussions and an open-ended questionnaire on students’ experiences of the transition to higher education (HE). Quantitative data on student characteristics and module results were obtained from Registry. Statistical analyses were performed using SPSS version 10. The study comprised two phases where phase one sought to enable the early detection of students at risk of poor performance by investigating the data set for patterns that may emerge between student achievement at Level 1 and entrance qualification, feeder institution, approaches to learning, conceptions of learning, course and teaching preferences and motivation. Phase one findings showed a trend of poorer performance by students who entered computing courses in HE with an AVCE entrance qualification. It was also shown that mature students scored more highly on the deep approach scale compared to their younger counterparts. Phase two investigated the data set for patterns that may emerge between student achievement at Level 2 and entrance qualification, approaches to learning, conceptions of learning and course and teaching preferences. Phase two, using action research, also sought to develop an intervention programme from the findings. This intervention programme was designed to improve aspects of information delivery to students; the personal tutor system, assessment régimes, Welcome Week, and teaching and learning. Piloting, evaluation and refinement of the intervention programme brought changes that were seen as positive by both staff and students. These changes included the Welcome Week Challenge which involved students in activities that sought to enhance students’ interactions with peers, personal tutors and the school and university facilities. These findings have shown that, for staff in wide access HE institutions, some knowledge of the previous educational experiences of their students, and the requirements of those students, are vital in providing a smooth transition to HE. A model of the characteristics of a successful student on computing courses in HE and a model for enhanced retention of diverse students on computing courses in HE were developed from the research findings. These models provide a significant contribution to current knowledge of those factors that enhance a smooth transition to HE and the characteristics of a successful student in a wide access university.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Instantaneous frequency and amplitude of complex signals based on quaternion Fourier transform
The ideas of instantaneous amplitude and phase are well understood for
signals with real-valued samples, based on the analytic signal which is a
complex signal with one-sided Fourier transform. We extend these ideas to
signals with complex-valued samples, using a quaternion-valued equivalent of
the analytic signal obtained from a one-sided quaternion Fourier transform
which we refer to as the hypercomplex representation of the complex signal. We
present the necessary properties of the quaternion Fourier transform,
particularly its symmetries in the frequency domain and formulae for
convolution and the quaternion Fourier transform of the Hilbert transform. The
hypercomplex representation may be interpreted as an ordered pair of complex
signals or as a quaternion signal. We discuss its derivation and properties and
show that its quaternion Fourier transform is one-sided. It is shown how to
derive from the hypercomplex representation a complex envelope and a phase.
A classical result in the case of real signals is that an amplitude modulated
signal may be analysed into its envelope and carrier using the analytic signal
provided that the modulating signal has frequency content not overlapping with
that of the carrier. We show that this idea extends to the complex case,
provided that the complex signal modulates an orthonormal complex exponential.
Orthonormal complex modulation can be represented mathematically by a polar
representation of quaternions previously derived by the authors. As in the
classical case, there is a restriction of non-overlapping frequency content
between the modulating complex signal and the orthonormal complex exponential.
We show that, under these conditions, modulation in the time domain is
equivalent to a frequency shift in the quaternion Fourier domain. Examples are
presented to demonstrate these concepts
Математична модель контактного з’єднання метало-пластмасових циліндричних оболонок
We consider alpha scale spaces, a parameterized class (alpha is an element of (0, 1]) of scale space representations beyond the well-established Gaussian scale space, which are generated by the alpha-th power of the minus Laplace operator on a bounded domain using the Neumann boundary condition. The Neumann boundary condition ensures that there is no grey-value flux through the boundary. Thereby no artificial grey-values from outside the image affect the evolution proces, which is the case for the alpha scale spaces on an unbounded domain. Moreover, the connection between the a scale spaces which is not trivial in the unbounded domain case, becomes straightforward: The generator of the Gaussian semigroup extends to a compact, self-adjoint operator on the Hilbert space L-2(Omega) and therefore it has a complete countable set of eigen functions. Taking the alpha-th power of the Gaussian generator simply boils down to taking the alpha-th power of the corresponding eigenvalues. Consequently, all alpha scale spaces have exactly the same eigen-modes and can be implemented simultaneously as scale dependent Fourier series. The only difference between them is the (relative) contribution of each eigen-mode to the evolution proces. By introducing the notion of (non-dimensional) relative scale in each a scale space, we are able to compare the various alpha scale spaces. The case alpha = 0.5, where the generator equals the square root of the minus Laplace operator leads to Poisson scale space, which is at least as interesting as Gaussian scale space and can be extended to a (Clifford) analytic scale space
Динамика интеграционных процессов ЕАЭС
Проведено исследование динамики интеграционных процессов и факторов, их определяющих. Отмечено, что ключевым моментом интеграции стран ЕАЭС является углубление кооперационных связей и формирование региональных цепочек добавленной стоимости
Антиутопия как диагноз будущему
Материалы XIV Междунар. науч. конф. студентов, магистрантов, аспирантов и молодых ученых, Гомель, 13–14 мая 2021 г
Prospective cohort study of radiotherapy with concomitant and adjuvant temozolomide chemotherapy for glioblastoma patients with no or minimal residual enhancing tumor load after surgery
Survival of glioblastoma patients has been linked to the completeness of surgical resection. Available data, however, were generated with adjuvant radiotherapy. Data confirming that extensive cytoreduction remains beneficial to patients treated with the current standard, concomitant temozolomide radiochemotherapy, are limited. We therefore analyzed the efficacy of radiochemotherapy for patients with little or no residual tumor after surgery. In this prospective, non-interventional multicenter cohort study, entry criteria were histological diagnosis of glioblastoma, small enhancing or no residual tumor on post-operative MRI, and intended temozolomide radiochemotherapy. The primary study objective was progression-free survival; secondary study objectives were survival and toxicity. Furthermore, the prognostic value of O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation was investigated in a subgroup of patients. One-hundred and eighty patients were enrolled. Fourteen were excluded by patient request or failure to initiate radiochemotherapy. Twenty-three patients had non-evaluable post-operative imaging. Thus, 143 patients qualified for analysis, with 107 patients having residual tumor diameters ≤1.5 cm. Median follow-up was 24.0 months. Median survival or patients without residual enhancing tumor exceeded the follow-up period. Median survival was 16.9 months for 32 patients with residual tumor diameters >0 to ≤1.5 cm (95% CI: 13.3–20.5, p = 0.039), and 13.9 months (10.3–17.5, overall p < 0.001) for 36 patients with residual tumor diameters >1.5 cm. Patient age at diagnosis and extent of resection were independently associated with survival. Patients with MGMT promoter methylated tumors and complete resection made the best prognosis. Completeness of resection acts synergistically with concomitant and adjuvant radiochemotherapy, especially in patients with MGMT promoter methylation
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