Évaluation environnementale des conséquences de la décarbonisation des services énergétiques

Abstract: The services provided by energy commodities are essential for human wellbeing but the reliance on fossil-fuels is jeopardising the livelihood of future generations and ecosystems, through global warming and other cause-effect pathways. There is an urgent need to transform the energy system, but this transformation may create unforeseen problems if not planned comprehensively. Many energy transitions plans rely on energy system optimisation models (ESOM), but these models are ill-prepared to evaluate the range of environmental stressors and their effects, and have oversimplified representations of production systems. An integrative approach combining ESOMs with life cycle assessment (LCA) can overcome the limitations of ESOMs, helping to avoid the ‘backfire’ of mitigation policies. This thesis gives an overview of the limitations of existing approaches linking ESOMs and LCA and implements a novel approach to overcome them. Several questions related to the energy transition in the province of Quebec (Canada) are assessed with the North American TIMES Energy Model (NATEM). The main scenario investigated, modelling the consequences of greenhouse gas (GHG) mitigation targets, is assessed from a life cycle perspective. To link both the optimization and the LCA models, a set of functions and procedures are encoded in an open-source software, that can be reused in other assessments. Results show that just a relatively narrow number of processes drive the changes in GHG, and this feature can be used to simplify the linking between TIMES and LCA models. The integrated ESOM-LCA assessment applied to Quebec indicates that global warming (GW) mitigation policies would reduce impacts on human health and biodiversity. This reduced impact is driven by reduced climate change but also other cause-effect mechanisms such as reduced water scarcity and metal contamination. Additionally, full-year building simulations of Quebec detached houses introduced as new technological options in NATEM suggest that better insulated buildings would reduce the total costs of GW mitigation. The introduction of low-carbon technologies could raise the costs of energy services by 20% but these costs could be substantially lowered with demand-side measures. ESOMs provide an interesting but limited perspective to plan energy transitions. The softlink of ESOMs with LCA is a viable approach to give a more comprehensive view of relative importance of cause-effect pathways affecting human health and biodiversity. The integrated assessment is a powerful tool to analyse a wide range of issues related to the needed energy transitions. Understanding the underlying assumptions and principles of models is also important to interpret and design assessments. To facilitate this kind of analysis, researchers should facilitate the reusability of their works, agreeing on output formats, documenting the code underlying the analyses, and providing tools to integrate models. To this end, scriptable open-source software tools are extremely useful. This thesis attempts to put a step forward in this direction.Les services énergétiques sont essentiels au bien-être humain, mais l’utilisation de combustibles fossiles pour répondre à la demande énergétique compromet les moyens de subsistance des générations futures et des écosystèmes, par le réchauffement climatique et d’autres menaces. Il est donc urgent de transformer le système énergétique existant. Cependant, cette transformation peut créer des problèmes imprévus si elle n’est pas planifiée de manière cohérente et complète. Plusieurs plans de transition énergétique reposent sur des modèles d'optimisation des systèmes énergétiques (MOSE), mais ces modèles sont peu adaptés pour évaluer les facteurs de stress environnementaux et leurs effets, et ils adoptent des représentations trop simplistes des systèmes de production. L’hypothèse de base de cette thèse est qu’une approche combinant les MOSE et l’analyse du cycle de vie (ACV) peut permettre de surmonter les limites des MOSE, en aidant à éviter des imprévus dans les politiques de réduction de gaz à effet de serre. Cette thèse donne un aperçu des limites des approches existantes reliant MOSE et ACV et met en oeuvre une méthodologie possible pour les surmonter. Plusieurs questions liées à la transition énergétique au Québec sont évaluées à l'aide d’un modèle TIMES (NATEM) pour la province de Québec. Le scénario de modélisation des conséquences des objectifs de réduction des gaz à effet de serre (GES) est ensuite évalué selon une perspective de cycle de vie. Pour relier les deux modèles, un ensemble de fonctions et de procédures est codé dans un langage open source (Python), qui peut être réutilisé dans d'autres évaluations. Les résultats montrent que seul un nombre relativement restreint de processus est à l'origine des changements dans la quantité de GES. Cette observation est utilisée pour simplifier la liaison entre les modèles TIMES et ACV. L'évaluation intégrée MOSE-ACV appliquée au Québec indique que les politiques de réduction de GES peuvent réduire les impacts sur la santé humaine et la biodiversité. Cette réduction d’impacts est due à la mitigation du changement climatique, mais également à d'autres mécanismes de cause à effet tels que la réduction de la pénurie d'eau et de la contamination par les métaux. De plus, la liaison des MOSE avec des modèles de simulation énergétique de bâtiments suggère que des bâtiments mieux isolés réduiraient les coûts totaux de réduction de GES. L'introduction de technologies à faibles émissions de carbone pourrait augmenter les coûts des services énergétiques de 20%, mais ces coûts pourraient être considérablement réduits grâce à des mesures axées sur la demande énergétique. Les MOSE offrent une perspective intéressante, mais limitée, pour planifier les transitions énergétiques. La liaison des MOSE avec ACV est une approche viable pour donner une vue plus complète de l’importance relative des mécanismes qui affectent la santé humaine et la biodiversité. L'évaluation intégrée est un outil puissant pour analyser une large gamme de problèmes liés aux transitions énergétiques. Comprendre les hypothèses et principes sous-jacents des modèles est également important pour interpréter les résultats. Pour faciliter ce type d'analyse, les chercheurs doivent faciliter la réutilisation de leurs travaux, en convenant des formats de sortie, en documentant le code sous-jacent aux analyses et en fournissant des outils pour intégrer les modèles. À cette fin, les outils open-source scriptables sont extrêmement utiles. Cette thèse tente de faire un pas en avant dans cette direction

Structured Chain-of-Thought Prompting for Few-Shot Generation of Content-Grounded QA Conversations

We introduce a structured chain-of-thought (SCoT) prompting approach to generating content-grounded multi-turn question-answer conversations using a pre-trained large language model (LLM). At the core of our proposal is a structured breakdown of the complex task into a number of states in a state machine, so that actions corresponding to various subtasks, e.g., content reading and utterance generation, can be executed in their own dedicated states. Each state leverages a unique set of resources including prompts and (optionally) additional tools to augment the generation process. Our experimental results show that SCoT prompting with designated states for hallucination mitigation increases agent faithfulness to grounding documents by up to 16.8%. When used as training data, our open-domain conversations synthesized from only 6 Wikipedia-based seed demonstrations train strong conversational QA agents; in out-of-domain evaluation, for example, we observe improvements of up to 13.9% over target domain gold data when the latter is augmented with our generated examples

Independent Component Analysis and Time-Frequency Masking for Speech Recognition in Multitalker Conditions

When a number of speakers are simultaneously active, for example in meetings or noisy public places, the sources of interest need to be separated from interfering speakers and from each other in order to be robustly recognized. Independent component analysis (ICA) has proven a valuable tool for this purpose. However, ICA outputs can still contain strong residual components of the interfering speakers whenever noise or reverberation is high. In such cases, nonlinear postprocessing can be applied to the ICA outputs, for the purpose of reducing remaining interferences. In order to improve robustness to the artefacts and loss of information caused by this process, recognition can be greatly enhanced by considering the processed speech feature vector as a random variable with time-varying uncertainty, rather than as deterministic. The aim of this paper is to show the potential to improve recognition of multiple overlapping speech signals through nonlinear postprocessing together with uncertainty-based decoding techniques

Finding Function in Form: Compositional Character Models for Open Vocabulary Word Representation

We introduce a model for constructing vector representations of words by composing characters using bidirectional LSTMs. Relative to traditional word representation models that have independent vectors for each word type, our model requires only a single vector per character type and a fixed set of parameters for the compositional model. Despite the compactness of this model and, more importantly, the arbitrary nature of the form-function relationship in language, our "composed" word representations yield state-of-the-art results in language modeling and part-of-speech tagging. Benefits over traditional baselines are particularly pronounced in morphologically rich languages (e.g., Turkish)

Should we use tactics or patterns to build secure systems?

Abstrac

Slide, Constrain, Parse, Repeat: Synchronous SlidingWindows for Document AMR Parsing

The sliding window approach provides an elegant way to handle contexts of sizes larger than the Transformer's input window, for tasks like language modeling. Here we extend this approach to the sequence-to-sequence task of document parsing. For this, we exploit recent progress in transition-based parsing to implement a parser with synchronous sliding windows over source and target. We develop an oracle and a parser for document-level AMR by expanding on Structured-BART such that it leverages source-target alignments and constrains decoding to guarantee synchronicity and consistency across overlapping windows. We evaluate our oracle and parser using the Abstract Meaning Representation (AMR) parsing 3.0 corpus. On the Multi-Sentence development set of AMR 3.0, we show that our transition oracle loses only 8\% of the gold cross-sentential links despite using a sliding window. In practice, this approach also results in a high-quality document-level parser with manageable memory requirements. Our proposed system performs on par with the state-of-the-art pipeline approach for document-level AMR parsing task on Multi-Sentence AMR 3.0 corpus while maintaining sentence-level parsing performance

Rendezvous Technique for the Treatment of Complete Common Bile Duct Transection After Multiple Hepatobiliary Surgeries

Common bile duct (CBD) injury during surgical procedures is a serious complication. Partial injury can usually be managed by a combination of percutaneous and/or endoscopic techniques. However, the management of complete transection of the CBD is very challenging. There are small case series of nonsurgical management of complete CBD transection during laparoscopic cholecystectomy. In this particular case, a 55-year-old female patient had multiple operations because of malignant pheochromocytoma with liver metastases. She developed a complete CBD transection during right hepatectomy. A biloma was managed with image-guided percutaneous drainage. However, both attempts of percutaneous transhepatic cholangiography (PTC) and endoscopic retrograde cholangiopancreatography (ERCP) for CBD stent were unsuccessful, as the native CBD was partially resected during the injury. A rendezvous procedure, in which a guidewire was placed through the distal CBD and into a biloma by ERCP and subsequently snared with PTC, allowed for a biliary-duodenal catheter to be placed successfully and achieve continuity of the patient's biliary tree.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140151/1/lap.2014.0374.pd

AMR Parsing with Instruction Fine-tuned Pre-trained Language Models

Instruction fine-tuned language models on a collection of instruction annotated datasets (FLAN) have shown highly effective to improve model performance and generalization to unseen tasks. However, a majority of standard parsing tasks including abstract meaning representation (AMR), universal dependency (UD), semantic role labeling (SRL) has been excluded from the FLAN collections for both model training and evaluations. In this paper, we take one of such instruction fine-tuned pre-trained language models, i.e. FLAN-T5, and fine-tune them for AMR parsing. Our extensive experiments on various AMR parsing tasks including AMR2.0, AMR3.0 and BioAMR indicate that FLAN-T5 fine-tuned models out-perform previous state-of-the-art models across all tasks. In addition, full fine-tuning followed by the parameter efficient fine-tuning, LoRA, further improves the model performances, setting new state-of-the-arts in Smatch on AMR2.0 (86.4), AMR3.0 (84.9) and BioAMR (82.3)

Bootstrapping Multilingual AMR with Contextual Word Alignments

We develop high performance multilingualAbstract Meaning Representation (AMR) sys-tems by projecting English AMR annotationsto other languages with weak supervision. Weachieve this goal by bootstrapping transformer-based multilingual word embeddings, in partic-ular those from cross-lingual RoBERTa (XLM-R large). We develop a novel technique forforeign-text-to-English AMR alignment, usingthe contextual word alignment between En-glish and foreign language tokens. This wordalignment is weakly supervised and relies onthe contextualized XLM-R word embeddings.We achieve a highly competitive performancethat surpasses the best published results forGerman, Italian, Spanish and Chinese

Variation and inheritance of iron reductase activity in the roots of common bean (Phaseolus vulgaris L.) and association with seed iron accumulation QTL

<p>Abstract</p> <p>Background</p> <p>Iron deficiency anemia is a global problem which often affects women and children of developing countries. Strategy I plants, such as common bean (<it>Phaseolus vulgaris </it>L.) take up iron through a process that involves an iron reduction mechanism in their roots; this reduction is required to convert ferric iron to ferrous iron. Root absorbed iron is critical for the iron nutrition of the plant, and for the delivery of iron to the shoot and ultimately the seeds. The objectives of this study were to determine the variability and inheritance for iron reductase activity in a range of genotypes and in a low × high seed iron cross (DOR364 × G19833), to identify quantitative trait loci (QTL) for this trait, and to assess possible associations with seed iron levels.</p> <p>Results</p> <p>The experiments were carried out with hydroponically grown plants provided different amounts of iron varying between 0 and 20 μM Fe(III)-EDDHA. The parents, DOR364 and G19833, plus 13 other cultivated or wild beans, were found to differ in iron reductase activity. Based on these initial experiments, two growth conditions (iron limited and iron sufficient) were selected as treatments for evaluating the DOR364 × G19833 recombinant inbred lines. A single major QTL was found for iron reductase activity under iron-limited conditions (1 μM Fe) on linkage group b02 and another major QTL was found under iron sufficient conditions (15 μM Fe) on linkage group b11. Associations between the b11 QTL were found with several QTL for seed iron.</p> <p>Conclusions</p> <p>Genes conditioning iron reductase activity in iron sufficient bean plants appear to be associated with genes contributing to seed iron accumulation. Markers for bean iron reductase (FRO) homologues were found with <it>in silico </it>mapping based on common bean synteny with soybean and <it>Medicago truncatula </it>on b06 and b07; however, neither locus aligned with the QTL for iron reductase activity. In summary, the QTL for iron reductase activity under iron limited conditions may be useful in environments where beans are grown in alkaline soils, while the QTL for iron reductase under sufficiency conditions may be useful for selecting for enhanced seed nutritional quality.</p