GIFTed Demons: deformable image registration with local structure-preserving regularization using supervoxels for liver applications.

Deformable image registration, a key component of motion correction in medical imaging, needs to be efficient and provides plausible spatial transformations that reliably approximate biological aspects of complex human organ motion. Standard approaches, such as Demons registration, mostly use Gaussian regularization for organ motion, which, though computationally efficient, rule out their application to intrinsically more complex organ motions, such as sliding interfaces. We propose regularization of motion based on supervoxels, which provides an integrated discontinuity preserving prior for motions, such as sliding. More precisely, we replace Gaussian smoothing by fast, structure-preserving, guided filtering to provide efficient, locally adaptive regularization of the estimated displacement field. We illustrate the approach by applying it to estimate sliding motions at lung and liver interfaces on challenging four-dimensional computed tomography (CT) and dynamic contrast-enhanced magnetic resonance imaging datasets. The results show that guided filter-based regularization improves the accuracy of lung and liver motion correction as compared to Gaussian smoothing. Furthermore, our framework achieves state-of-the-art results on a publicly available CT liver dataset

Registration of serial sections: An evaluation method based on distortions of the ground truths

Registration of histological serial sections is a challenging task. Serial sections exhibit distortions and damage from sectioning. Missing information on how the tissue looked before cutting makes a realistic validation of 2D registrations extremely difficult. This work proposes methods for ground-truth-based evaluation of registrations. Firstly, we present a methodology to generate test data for registrations. We distort an innately registered image stack in the manner similar to the cutting distortion of serial sections. Test cases are generated from existing 3D data sets, thus the ground truth is known. Secondly, our test case generation premises evaluation of the registrations with known ground truths. Our methodology for such an evaluation technique distinguishes this work from other approaches. Both under- and over-registration become evident in our evaluations. We also survey existing validation efforts. We present a full-series evaluation across six different registration methods applied to our distorted 3D data sets of animal lungs. Our distorted and ground truth data sets are made publicly available.Comment: Supplemental data available under https://zenodo.org/record/428244

Contribution à la durabilité de la gestion de la biomasse solide en République Démocratique du Congo

Cette étude porte sur la contribution des acteurs de la biomasse solide (BS) à la durabilité de la gestion de celle-ci en République démocratique du Congo (RDC). La problématique s'articule sur la question centrale suivante : la gestion de la biomasse solide peut-elle favoriser la durabilité de cette ressource énergétique en RDC? À cet égard, trois axes majeurs ont été étudiés pour cerner les facteurs susceptibles de compromettre ou de promouvoir la gestion durable de la BS en RDC : • Les facteurs qui agissent sur la filière de la BS concernant les aspects techniques, allant de la production à la carbonisation, au défournement, à la récolte, au transport et enfin à la commercialisation de ladite ressource en RDC; • Les facteurs liés aux aspects règlementaires concernant le cadre juridique appliqué à la BS en RDC; • Les facteurs en lien avec les aspects organisationnels, institutionnels et ceux de la gouvernance forestière en RDC. Les trois objectifs suivants permettent d'analyser la question de la durabilité de gestion de la biomasse solide :1. Réaliser le diagnostic du contexte et de la pratique de l'utilisation de la BS en RDC en vue de ressortir les facteurs qui contribuent aux forces et faiblesses de cette pratique. De ce fait, l'approche d'analyse stratégique « forces, faiblesses, opportunités, menaces » (FFOM ou SWOT en anglais) a aidé à déceler les maillons qui permettent de définir les conditions et les occasions favorisant les trois piliers du développement durable que sont l'environnement, le social et l'économie; 2. Évaluer le degré de durabilité d'utilisation de la BS actuelle. Cela a conduit à faire une analyse des cadres législatifs, règlementaires et normatifs, ainsi que des aspects organisationnels, institutionnels et modernes de la gestion de la BS en RDC. Par conséquent, une esquisse de la gouvernance de la BS en RDC a été proposée pour stimuler l'analyse des instruments qui traitent des questions de cadres juridiques et coutumiers susceptibles d'influencer ces normes; 3. Proposer des éléments d'amélioration du contexte, de la pratique et du respect de la réglementation de l'utilisation de la BS qui favorisent un modèle de la gestion participative de l'utilisation durable de cette énergie. Pour ce faire, l'étude présente les facteurs de la durabilité de la gestion de la bioénergie et leurs interrelations dans le but de mettre sur pied un modèle de gestion participative de la bioénergie permettant de répondre au développement durable de la BS en RDC. Au regard des axes clés énumérés, la nécessité de faire ressortir un modèle de réponses fiables et palpables avec à la clé la gestion et l'utilisation de la BS respectant les principes du développement durable s'avère indispensable en RDC. De ce fait, le modèle de table de concertation des acteurs de la BS en RDC est élaboré.This thesis focuses on the contribution to the sustainability of the management of solid biomass (SB) in the Democratic Republic of Congo (DRC). This study revolves around the following central question: Can the management of solid biomass promote the sustainability of this energy resource in the DRC? Three major axes were studied to identify the factors likely to compromise or promote the sustainable management of SB in the DRC: • The factors acting on the SB sector focus on the related technical aspects, ranging from production, carbonization, excavation, harvesting, transport and to the marketing of this resource in the DRC; • Factors related to regulatory aspects concerning the legal framework applied to SB in the DRC; • The factors structuring the organizational and institutional aspects and those of forest governance in the DRC. The three following objectives were analyzed to answer the issue of the sustainability of solid biomass management: 1. Carry out the diagnosis of the context and practice of the use of SB in the DRC to highlight the factors that contribute to the strengths and weaknesses of this practice. The SWOT strategic analysis approach was used to identify the links that define the strengths, weaknesses, opportunities and threats for the three pillars of sustainable development that are environmental, social and economic. 2. Assess the level of sustainability of the actual use of SB with a focus on improving the factors of non-sustainability. This led to an analysis of the legislative, regulatory and normative frameworks, as well as the organizational, institutional and modern aspects of BS management in the DRC. An outline of SB governance in the DRC has been proposed to stimulate analysis of instruments addressing issues of legal frameworks and customary that influence these norms. 3. Propose elements for improving the context, practice, and compliance with the regulations for the use of SB that promote a participatory management model for the sustainable use of this energy source. To do this, the factors of the sustainability of bioenergy management and their interrelationships were presented with the aim of setting up a participatory bioenergy management model to respond to the development of SB in DRC. Regarding the key axes listed above, the need to develop and implement a model of reliable and tangible responses, with the management and use of SB thus respecting the principles of sustainable development, is essential in the DRC. As a result, the consultation table model for SB actors in the DRC is elaborated