3,077 research outputs found
Cardiac cell modelling: Observations from the heart of the cardiac physiome project
In this manuscript we review the state of cardiac cell modelling in the context of international initiatives such as the IUPS Physiome and Virtual Physiological Human Projects, which aim to integrate computational models across scales and physics. In particular we focus on the relationship between experimental data and model parameterisation across a range of model types and cellular physiological systems. Finally, in the context of parameter identification and model reuse within the Cardiac Physiome, we suggest some future priority areas for this field
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DWT/PCA face recognition using automatic coefficient selection
In PCA-based face recognition, there is often a trade-off between selecting the most relevant parts of a face image for recognition and not discarding information which may be useful. The work presented in this paper proposes a method to automatically determine the most discriminative coefficients in a DWT/PCA-based face recognition system, based on their inter-class and intra-class standard deviations. In addition, the eigenfaces used for recognition are generally chosen based on the value of their associated eigenvalues. However, the variance indicated by the eigenvalues may be due to factors such as variation in illumination levels between training set faces, rather than differences that are useful for identification. The work presented proposes a method to automatically determine the most discriminative eigenfaces, based on the inter-class and intra-class standard deviations of the training set eigenface weight vectors. The results obtained using the AT&T database show an improvement over existing DWT/PCA coefficient selection techniques
Hubungan gaya pembelajaran dengan pencapaian akademik pelajar aliran vokasional
Analisis keputusan Sijil Pelajaran Malaysia (SPM) 2011 menunjukkan penurunan
pencapaian bagi Sekolah Menengah Vokasional. Oleh itu, kajian ini dilaksanakan
bertujuan untuk mengkaji hubungan di antara gaya pembelajaran dengan pencapaian
akademik pelajar. Kajian ini juga ingin mengenalpasti gaya pembelajaran paling
dominan yang diamalkan oleh pelajar serta melihat perbezaan gaya pembelajaran
dengan jantina pelajar. Seramai 131 orang Pelajar Tingkatan Empat Kursus
Vokasional Di Sekolah Menengah Vokasional Segamat di Johor telah terlibat dalam
kajian ini. Soal selidik Index of Learning Style (ILS) yang dibangunkan oleh Felder
dan Silverman (1991) yang mengandungi 44 soalan telah digunakan untukh
menjalankan kajian ini. Gaya pembelajaran pelajar dapat dilihat melalui empat
dimensi gaya pembelajaran yang terdiri dari dua sub-skala yang bertentangan iaitu
dimensi pelajar Aktif dan Reflektif, dimensi pelajar Konkrit dan Intuitif, dimensi
pelajar Verbal dan Visual, serta dimensi pelajar Tersusun dan Global. Data yang
diperolehi dianalisis dengan menggunakan perisian Statistical Package for Social
Science for WINDOW release 20.0 (SPSS.20.0). Ujian Korelasi Pearson digunakan
untuk menganalisis data dalam mengkaji hubungan gaya pembelajaran dengan
pencapaian akademik pelajar. Nilai pekali p yang diperolehi di antara gaya
pembelajaran dengan pencapaian pelajar adalah (p=0.1 hingga 0.4). Ini menunjukkan
tidak terdapat hubungan yang signifikan di antara dua pembolehubah tersebut. Kajian
ini juga mendapati bahawa gaya pembelajaran yang menjadi amalan pelajar ialah
gaya pembelajaran Tersusun. Hasil kajian juga mendapati bahawa tidak terdapat
perbezaan yang signifikan di antara gaya pembelajaran dengan jantina pelajar
The Life-Cycle Income Analysis Model (LIAM): a study of a flexible dynamic microsimulation modelling computing framework
This paper describes a flexible computing framework designed to create a dynamic microsimulation model, the Life-cycle Income Analysis Model (LIAM). The principle computing characteristics include the degree of modularisation, parameterisation, generalisation and robustness. The paper describes the decisions taken with regard to type of dynamic model used. The LIAM framework has been used to create a number of different microsimulation models, including an Irish dynamic cohort model, a spatial dynamic microsimulation model for Ireland, an indirect tax and consumption model for EU15 as part of EUROMOD and a prototype EU dynamic population microsimulation model for 5 EU countries. Particular consideration is given to issues of parameterisation, alignment and computational efficiency.flexible; modular; dynamic; alignment; parameterisation; computational efficiency
Governing equations of tissue modelling and remodelling: A unified generalised description of surface and bulk balance
Several biological tissues undergo changes in their geometry and in their
bulk material properties by modelling and remodelling processes. Modelling
synthesises tissue in some regions and removes tissue in others. Remodelling
overwrites old tissue material properties with newly formed, immature tissue
properties. As a result, tissues are made up of different "patches", i.e.,
adjacent tissue regions of different ages and different material properties,
within evolving boundaries. In this paper, generalised equations governing the
spatio-temporal evolution of such tissues are developed within the continuum
model. These equations take into account nonconservative, discontinuous surface
mass balance due to creation and destruction of material at moving interfaces,
and bulk balance due to tissue maturation. These equations make it possible to
model patchy tissue states and their evolution without explicitly maintaining a
record of when/where resorption and formation processes occurred. The time
evolution of spatially averaged tissue properties is derived systematically by
integration. These spatially-averaged equations cannot be written in closed
form as they retain traces that tissue destruction is localised at tissue
boundaries.
The formalism developed in this paper is applied to bone tissues, which
exhibit strong material heterogeneities due to their slow mineralisation and
remodelling processes. Evolution equations are proposed in particular for
osteocyte density and bone mineral density. Effective average equations for
bone mineral density (BMD) and tissue mineral density (TMD) are derived using a
mean-field approximation. The error made by this approximation when remodelling
patchy tissue is investigated. The specific time signatures of BMD or TMD
during remodelling events may provide a way to detect these events occurring at
lower, unseen spatial resolutions from microCT scans.Comment: 14 pages, 8 figures. V2: minor stylistic changes, more detailed
derivation of Eqs (30)-(31), additional comments on implication of BMD and
TMD signatures for microCT scan
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