32,278 research outputs found
Computerized Analysis of Magnetic Resonance Images to Study Cerebral Anatomy in Developing Neonates
The study of cerebral anatomy in developing neonates is of great importance for
the understanding of brain development during the early period of life. This
dissertation therefore focuses on three challenges in the modelling of cerebral
anatomy in neonates during brain development. The methods that have been
developed all use Magnetic Resonance Images (MRI) as source data.
To facilitate study of vascular development in the neonatal period, a set of image
analysis algorithms are developed to automatically extract and model cerebral
vessel trees. The whole process consists of cerebral vessel tracking from
automatically placed seed points, vessel tree generation, and vasculature
registration and matching. These algorithms have been tested on clinical Time-of-
Flight (TOF) MR angiographic datasets.
To facilitate study of the neonatal cortex a complete cerebral cortex segmentation
and reconstruction pipeline has been developed. Segmentation of the neonatal
cortex is not effectively done by existing algorithms designed for the adult brain
because the contrast between grey and white matter is reversed. This causes pixels
containing tissue mixtures to be incorrectly labelled by conventional methods. The
neonatal cortical segmentation method that has been developed is based on a novel
expectation-maximization (EM) method with explicit correction for mislabelled
partial volume voxels. Based on the resulting cortical segmentation, an implicit
surface evolution technique is adopted for the reconstruction of the cortex in
neonates. The performance of the method is investigated by performing a detailed
landmark study.
To facilitate study of cortical development, a cortical surface registration algorithm
for aligning the cortical surface is developed. The method first inflates extracted
cortical surfaces and then performs a non-rigid surface registration using free-form
deformations (FFDs) to remove residual alignment. Validation experiments using
data labelled by an expert observer demonstrate that the method can capture local
changes and follow the growth of specific sulcus
STV-based Video Feature Processing for Action Recognition
In comparison to still image-based processes, video features can provide rich and intuitive information about dynamic events occurred over a period of time, such as human actions, crowd behaviours, and other subject pattern changes. Although substantial progresses have been made in the last decade on image processing and seen its successful applications in face matching and object recognition, video-based event detection still remains one of the most difficult challenges in computer vision research due to its complex continuous or discrete input signals, arbitrary dynamic feature definitions, and the often ambiguous analytical methods. In this paper, a Spatio-Temporal Volume (STV) and region intersection (RI) based 3D shape-matching method has been proposed to facilitate the definition and recognition of human actions recorded in videos. The distinctive characteristics and the performance gain of the devised approach stemmed from a coefficient factor-boosted 3D region intersection and matching mechanism developed in this research. This paper also reported the investigation into techniques for efficient STV data filtering to reduce the amount of voxels (volumetric-pixels) that need to be processed in each operational cycle in the implemented system. The encouraging features and improvements on the operational performance registered in the experiments have been discussed at the end
Safety Net Design and Systemic Risk: New Empirical Evidence
Recent econometric evidence has noticeably changed views on the desirability and the appropriate design of explicit Deposit Insurance Schemes (DIS). The purpose of this paper is to take a second look at the data. After surveying recent empirical work and providing a theoretical framework, we argue that existing studies may suffer from a selection bias. Building on a new database on explicit deposit insurance compiled by the author, we perform a variety of semi-parametric and parametric tests to see whether and how explicit deposit insurance (de)stabilizes banking systems. We find that the evidence indeed suggests that a selection bias is present. Controlling for this bias leads to a reassessment of recent studies. In particular, making deposit insurance explicit has a rather moderate and, if any, stabilizing effect on the probability of experiencing a systemic crisis
The effect of investment tax credit: Evidence from an atypical programme in Italy
This paper examines how business investment responds to investment tax credit, as enacted by ItalyĂâs Law 388/2000. To assess whether the programme made investments possible that otherwise would not have been made, it exploits some features of the tax credit scheme, such as the fact that some Italian regions are not deemed eligible or that the amount of the bonus differs across eligible regions. Although the programme was fiscally unsustainable, and was therefore downsized well ahead of the expiry date, our findings suggest that it has been effective in stimulating investment.investment incentives, state aid
Policies for local development: an evaluation of Italy's "Patti Territoriali"
In Italy, Patti Territoriali (Territorial Pacts) are one of the main government-sponsored programmes to foster growth in disadvantaged areas. A territorial pact is an agreement among the local authorities and representatives of civil society (mainly entrepreneurs and trade unions) of a number of neighbouring municipalities that is subsequently endorsed by the central government. It consists in a fully-fledged development plan, including a series of private and public investments for which public funding is provided. This paper evaluates the effectiveness of territorial pacts by comparing the economic performance, in terms of employment and number of plants, of participating municipalities with a sample of municipalities not involved in the policy. The results suggest that the programme has been largely ineffective in stimulating growth.regional aid, regional growth, ownership
Pension systems and reform conceptual framework
The WorldBank's conceptual framework to assess pension systems and reform options evaluates initial conditions and the capacity to improve the enabling environment, and then focuses on how best to work within these to achieve the core objectives of pension systems - protection against the risk of poverty in old age and smoothing consumption from one's work life into retirement. The Bank applies a multi-pillared approach towards pension system modalities to address the needs of target populations including: (i) a non-contributory'zero pillar'extending some level of old-age income security to all of the elderly; (ii) an appropriately sized mandatory'first pillar'with the objective of replacing some portion of lifetime pre-retirement income through contributions linked to earnings; (iii) a funded mandatory defined-contribution'second pillar'that typically provides privately-managed individual savings accounts; (iv) a funded voluntary'third-pillar;'and (v) a non-financial'fourth pillar.'The primary evaluation criteria are the ability of the system to maintain adequacy, affordability, sustainability, equity, predictability, and robustness. The secondary evaluation criteria are the system's capacity to: minimize labor market distortions; contribute to savings mobilization; and contribute to financial market development. Because pension benefits are claims against future economic output, it is essential that over time pension systems contribute to growth and output to support the promised benefits. Going forward, the Bank is focusing on strengthening its support in: (a) establishing a clearer results framework to assess pension systems and reforms; (b) enhancing knowledge management, including research and learning; and (c) improving implementation capacity.Emerging Markets,Debt Markets,Environmental Economics&Policies,Pensions&Retirement Systems,Banks&Banking Reform
Safety Net Design and Systemic Risk: New Empirical Evidence
Recent econometric evidence has noticeably changed views on the desirability and the appropriate design of explicit Deposit Insurance Schemes (DIS). The purpose of this paper is to take a second look at the data. After surveying recent empirical work and providing a theoretical framework, we argue that existing studies may suffer from a selection bias. Building on a new database on explicit deposit insurance compiled by the author, we perform a variety of semi-parametric and parametric tests to see whether and how explicit deposit insurance (de)stabilizes banking systems. We find that the evidence indeed suggests that a selection bias is present. Controlling for this bias leads to a reassessment of recent studies. In particular, making deposit insurance explicit has a rather moderate and, if any, stabilizing effect on the probability of experiencing a systemic crisis.Deposit Insurance ; Banking Fragility ; Systemic Risk
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