Разработка и программная реализация механизма хранения и управления связями между объектами САПР БПО

Система автоматизированного проектирования бортового программного обеспечения (САПР БПО) должна решать задачи систематизации проектных данных об изделиях. Каждое изделие описывается в терминах САПР БПО и состоит из набора сложных информационных объектов, каждый из которых состоит из нескольких простых информационных объектов. Любой простой объект может входит в состав нескольких составных объектов. Целью работы является поиск методов и разработка средств поиска вхождения простых объектов в состав сложных, копирования сложных объектов из состава одного изделия в состав другого, удаления/модификации простых и сложных объектов с оценкой влияния на все изделия, в состав которых входит данный объект.The computer-aided design software for onboard software (CAD BPO) should solve the problem of systematization of design data about products. Each product is described in terms of CAD software and consists of a set of complex information objects, each of which consists of several simple information objects. Any simple object may be part of several composite objects. The aim of the work is to search for methods and develop tools for finding the entry of simple objects into complex, copying complex objects from one product into another, removing / modifying simple and complex objects with an assessment of the impact on all products that include this object

Automatic Segmentation of Human Cortical Layer-Complexes and Architectural Areas Using Ex vivo Diffusion MRI and Its Validation

Recently, several magnetic resonance imaging contrast mechanisms have been shown to distinguish cortical substructure corresponding to selected cortical layers. Here, we investigate cortical layer and area differentiation by automatized unsupervised clustering of high-resolution diffusion MRI data. Several groups of adjacent layers could be distinguished in human primary motor and premotor cortex. We then used the signature of diffusion MRI signals along cortical depth as a criterion to detect area boundaries and find borders at which the signature changes abruptly. We validate our clustering results by histological analysis of the same tissue. These results confirm earlier studies which show that diffusion MRI can probe layer-specific intracortical fiber organization and, moreover, suggests that it contains enough information to automatically classify architecturally distinct cortical areas. We discuss the strengths and weaknesses of the automatic clustering approach and its appeal for MR-based cortical histology

Multistage Background Field Removal (MUBAFIRE)-Compensating for B0 Distortions at Ultra-High Field

The investigation of tissue magnetic susceptibility and the resultant magnetic field offers a new avenue for quantitative tissue characterisation by MRI. One crucial step in mining the phase and field data for relevant tissue information is the correction of externally induced field shifts. This article outlines a multistep approach comprising several methodologies for background field removal. The virtues of B0 long-range variation detection and compensation of more localised external disturbances are unified in a sequential filter chain. The algorithm is tested by means of a numerical Monte Carlo simulation model and applied to in vivo measurements at 3T and 9.4T as well as to a fixed brain tissue measurement at 9.4T. Further, a comparison to conventional filter types has been undertaken

Local site conditions and seismic risk assessment of historic buildings

The objectives of the Istanbul Seismic Risk Mitigation and Emergency Preparedness Project are to improve Istanbul’s preparedness for a potential earthquake. Within this framework “Risk Assessment of Cultural Heritage Buildings” was designed to address the vulnerability of cultural assets, specifically buildings with global cultural heritage value. One of the components of the project was the vulnerability and risk assessment of 170 historic buildings of varied age, value and state of conservation, distributed over several square miles. Many of these buildings have public functions such as museums or education establishments. Among the most famous are Topkapı Palace and Hagia Irene museum. After a discussion of the choice of the most appropriate earthquake scenario, the methodology used for assessing the effects of local site conditions on the seismic performance of selected cultural heritage buildings is presented. The purpose is to estimate the earthquake characteristics on the ground surface based on the probabilistic and deterministic hazard studies. The site specific elastic design spectra for each site are then manipulated to obtain site specific nonlinear displacement spectra, so that these can be directly compared with capacity curves for the buildings obtained by using mechanism approach limit state analysis. The procedure for obtaining the capacity curves is described and the choice of the most appropriate level of ductility and the equivalent reduction coefficient are discussed. A procedure to evaluate performance points and to define safety factors based on lateral acceleration, drift or expected damage level, is presented. The process of arriving at a risk evaluation and hence recommendation for strengthening or otherwise, is finally highlighted with respect to four comparable case studies

Measurement series at 3T.

<p>From top to bottom the field map, DIPF, MUBAFIRE and MUBAFIRE Local correction for five samples of the 3T study are shown. The bottom row illustrates histograms of the field distribution for the correction algorithms in each sample.</p

Parameter Optimisation.

<p>From left to right, the resulting error for standalone SPHINX, DIPF and MUBAFIRE are shown for a range of parameterisations. The rightmost graph illustrates the required computing time for MUBAFIRE.</p

Quantitative water content mapping at clinically relevant field strengths: A comparative study at 1.5T and 3T

PurposeQuantitative water content mapping in vivo using MRI is a very valuable technique to detect, monitor and understand diseases of the brain. At 1.5 T, this technology has already been successfully used, but it has only recently been applied at 3 T because of significantly increased RF field inhomogeneity at the higher field strength. To validate the technology at 3 T, we estimate and compare in vivo quantitative water content maps at 1.5 T and 3 T obtained with a protocol proposed recently for 3 T MRI.MethodsThe proposed MRI protocol was applied on twenty healthy subjects at 1.5 T and 3 T; the same post-processing algorithms were used to estimate the water content maps. The 1.5 T and 3 T maps were subsequently aligned and compared on a voxel-by-voxel basis. Statistical analysis was performed to detect possible differences between the estimated 1.5 T and 3 T water maps.ResultsOur analysis indicates that the water content values obtained at 1.5 T and 3 T did not show significant systematic differences. On average the difference did not exceed the standard deviation of the water content at 1.5 T. Furthermore, the contrast-to-noise ratio (CNR) of the estimated water content map was increased at 3 T by a factor of at least 1.5.ConclusionsVulnerability to RF inhomogeneity increases dramatically with the increasing static magnetic field strength. However, using advanced corrections for the sensitivity profile of the MR coils, it is possible to preserve quantitative accuracy while benefiting from the increased CNR at the higher field strength. Indeed, there was no significant difference in the water content values obtained in the brain at 1.5 T and 3 T

Simulation scheme.

<p>A gradient echo measurement is used to estimate a <math><msubsup><mi>T</mi><mn>2</mn><mo>*</mo></msubsup></math> map. Using the <math><msubsup><mi>T</mi><mn>2</mn><mo>*</mo></msubsup></math> anatomy and rescaling the values to an appropriate range, a susceptibility distribution is generated. Random susceptibility structures are added and dipole convolution generates the susceptibility-induced field map and a local reference. External disturbances are introduced as randomised spherical harmonic functions and noise is added. After BFR correction the results are compared to the reference field.</p

Increasing body mass index in an elderly cohort: Effects on the quantitative MR parameters of the brain

BackgroundBody mass index (BMI) is increasing in a large number of elderly persons. This increase in BMI is known to put one at risk for many "diseases of aging," although less is known about how a change in BMI may affect the brains of the elderly.PurposeTo investigate the relationship between BMI and quantitative water content, T1, T2*, and the semi‐quantitative magnetization transfer ratio (MTR) of various structures in elderly brains.Study TypeCross‐sectional.SubjectsForty‐two adults (BMI range: 19.1–33.5 kg/m2, age range: 58–80 years).Field Strength3T MRI (two multi‐echo gradient echoes, actual flip angle imaging, magnetization prepared rapid gradient echo, fluid attenuated inversion recovery).AssessmentThe 3D two‐point method was used to derive (semi‐)quantitative parameters in global white (WM) and gray matter (GM) and their regions as defined by the Johns Hopkins University and the Montreal Neurological Institute atlases.Statistical TestsMultivariate linear regression with BMI as principal regressor, corrected for the additional regressors age, gender, and glycated hemoglobin. Spearman correlation between quantitative parameters of the regions showing significant changes and the lipid spectra / C‐reactive protein (CRP). Voxel‐based morphometry and analysis of covariance (ANCOVA) to explore changes in the GM volume.ResultsT1 increased significantly (P < 0.05) in the frontal, temporal, and parietal cortices, while the bilateral corona radiata, right superior longitudinal fasciculus, as well as the corpus callosum showed significant changes in the WM regions. T2* increased significantly in the global WM and left corona radiata. Changes in MTR and the free water content did not reach significance. No significant correlation between any quantitative parameter and the lipid spectra or CRP could be identified.Data ConclusionThese results suggest that an elevated BMI predominantly affects T1 in WM as well as GM structures in the elderly human brain