Letteratura scientifica selezionata sul tema "Conditional Search Space"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Consulta la lista di attuali articoli, libri, tesi, atti di convegni e altre fonti scientifiche attinenti al tema "Conditional Search Space".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Articoli di riviste sul tema "Conditional Search Space":
1
Bryce, D., S. Kambhampati e D. E. Smith. "Planning Graph Heuristics for Belief Space Search". Journal of Artificial Intelligence Research 26 (30 maggio 2006): 35–99. http://dx.doi.org/10.1613/jair.1869.
Abstract (sommario):
Some recent works in conditional planning have proposed reachability heuristics to improve planner scalability, but many lack a formal description of the properties of their distance estimates. To place previous work in context and extend work on heuristics for conditional planning, we provide a formal basis for distance estimates between belief states. We give a definition for the distance between belief states that relies on aggregating underlying state distance measures. We give several techniques to aggregate state distances and their associated properties. Many existing heuristics exhibit a subset of the properties, but in order to provide a standardized comparison we present several generalizations of planning graph heuristics that are used in a single planner. We compliment our belief state distance estimate framework by also investigating efficient planning graph data structures that incorporate BDDs to compute the most effective heuristics. We developed two planners to serve as test-beds for our investigation. The first, CAltAlt, is a conformant regression planner that uses A* search. The second, POND, is a conditional progression planner that uses AO* search. We show the relative effectiveness of our heuristic techniques within these planners. We also compare the performance of these planners with several state of the art approaches in conditional planning.
2
BOKHONSKY, A. I. "SEARCH EXTREME FUNCTIONAL". Fundamental and Applied Problems of Engineering and Technology 4, n. 1 (2020): 144–49. http://dx.doi.org/10.33979/2073-7408-2020-342-4-1-144-149.
Abstract (sommario):
Examples illustrate the developed procedure for checking the sufficient condition for the extremum of a functional (construction of its mathematical image); in the problem of the calculus of variations on a conditional extremum, the role of the Lagrange multiplier is estimated and the surface of the functional is constructed in terms of the parameters of variations of admissible functions of a normalized linear space.
3
Park, Gunju, e Youngmin Yi. "CondNAS: Neural Architecture Search for Conditional CNNs". Electronics 11, n. 7 (31 marzo 2022): 1101. http://dx.doi.org/10.3390/electronics11071101.
Abstract (sommario):
As deep learning has become prevalent and adopted in various application domains, the need for efficient convolution neural network (CNN) inference on diverse target platforms has increased. To address the need, a neural architecture search (NAS) technique called once-for-all, or OFA, which aims to efficiently find the optimal CNN architecture for the given target platform using genetic algorithm (GA), has recently been proposed. Meanwhile, a conditional CNN architecture, which allows early exits with auxiliary classifiers in the middle of a network to achieve efficient inference without accuracy loss or with negligible loss, has been proposed. In this paper, we propose a NAS technique for the conditional CNN architecture, CondNAS, which efficiently finds a near-optimal conditional CNN architecture for the target platform using GA. By attaching auxiliary classifiers through adaptive pooling, OFA’s SuperNet is successfully extended, such that it incorporates the various conditional CNN sub-networks. In addition, we devise machine learning-based prediction models for the accuracy and latency of an arbitrary conditional CNN, which are used in the GA of CondNAS to efficiently explore the large search space. The experimental results show that the conditional CNNs from CondNAS is 2.52× and 1.75× faster than the CNNs from OFA for Galaxy Note10+ GPU and CPU, respectively.
4
Yuan, Xiaojian, Kejiang Chen, Jie Zhang, Weiming Zhang, Nenghai Yu e Yang Zhang. "Pseudo Label-Guided Model Inversion Attack via Conditional Generative Adversarial Network". Proceedings of the AAAI Conference on Artificial Intelligence 37, n. 3 (26 giugno 2023): 3349–57. http://dx.doi.org/10.1609/aaai.v37i3.25442.
Abstract (sommario):
Model inversion (MI) attacks have raised increasing concerns about privacy, which can reconstruct training data from public models. Indeed, MI attacks can be formalized as an optimization problem that seeks private data in a certain space. Recent MI attacks leverage a generative adversarial network (GAN) as an image prior to narrow the search space, and can successfully reconstruct even the high-dimensional data (e.g., face images). However, these generative MI attacks do not fully exploit the potential capabilities of the target model, still leading to a vague and coupled search space, i.e., different classes of images are coupled in the search space. Besides, the widely used cross-entropy loss in these attacks suffers from gradient vanishing. To address these problems, we propose Pseudo Label-Guided MI (PLG-MI) attack via conditional GAN (cGAN). At first, a top-n selection strategy is proposed to provide pseudo-labels for public data, and use pseudo-labels to guide the training of the cGAN. In this way, the search space is decoupled for different classes of images. Then a max-margin loss is introduced to improve the search process on the subspace of a target class. Extensive experiments demonstrate that our PLG-MI attack significantly improves the attack success rate and visual quality for various datasets and models, notably, 2 ∼ 3× better than state-of-the-art attacks under large distributional shifts. Our code is available at: https://github.com/LetheSec/PLG-MI-Attack.
5
MALI, AMOL DATTATRAYA, e MINH TANG. "STATE-SPACE PLANNING WITH VARIANTS OF A*". International Journal on Artificial Intelligence Tools 15, n. 03 (giugno 2006): 433–64. http://dx.doi.org/10.1142/s0218213006002758.
Abstract (sommario):
Significant advances have occurred in heuristic search for planning in the last eleven years. Many of these planners use A*-style search. We report on five sound and complete domain-independent forward state-space STRIPS planners in this paper. The planners are AWA* (Adjusted Weighted A*), MAWA* (Modified AWA*), AWA*-AC (AWA* with action conflict-based adjustment), AWA*-PD (AWA* with deleted preconditions-based adjustment), and AWA*-AC-LE (AWA*-AC with lazy evaluation). AWA* is the first planner to use node-dependent weighting in A*. MAWA*, AWA*-AC, AWA*-PD, and AWA*-AC-LE use conditional two-phase heuristic evaluation. MAWA* applies node-dependent weighting to a subset of the nodes in the fringe, after the two-phase evaluation. One novel idea in AWA*-AC-LE is lazy heuristic evaluation which does not construct relaxed plans to compute heuristic values for all nodes. We report on an empirical comparison of AWA*, MAWA*, AWA*-AC, AWA*-PD, and AWA*-AC-LE with classical planners AltAlt, FF, HSP-2 and STAN 4. Our variants of A* outperform these planners on several problems. The empirical evaluation shows that heuristic search planning is significantly benefitted by node-dependent weighting, conditional two-phase heuristic evaluation and lazy evaluation. We report on the insights about inferior performance of our planners in some domains using the notion of waiting time. We discuss many other variants of A*, state-space planners and directions for future work.
6
Marinescu, Radu, Akihiro Kishimoto e Adi Botea. "Parallel AND/OR Search for Marginal MAP". Proceedings of the AAAI Conference on Artificial Intelligence 34, n. 06 (3 aprile 2020): 10226–34. http://dx.doi.org/10.1609/aaai.v34i06.6584.
Abstract (sommario):
Marginal MAP is a difficult mixed inference task for graphical models. Existing state-of-the-art algorithms for solving exactly this task are based on either depth-first or best-first sequential search over an AND/OR search space. In this paper, we explore and evaluate for the first time the power of parallel search for exact Marginal MAP inference. We introduce a new parallel shared-memory recursive best-first AND/OR search algorithm that explores the search space in a best-first manner while operating with limited memory. Subsequently, we develop a complete parallel search scheme that only parallelizes the conditional likelihood computations. We also extend the proposed algorithms into depth-first parallel search schemes. Our experiments on difficult benchmarks demonstrate the effectiveness of the parallel search algorithms against current sequential methods for solving Marginal MAP exactly.
7
Payne, R. D., N. Guha, Y. Ding e B. K. Mallick. "A conditional density estimation partition model using logistic Gaussian processes". Biometrika 107, n. 1 (5 dicembre 2019): 173–90. http://dx.doi.org/10.1093/biomet/asz064.
Abstract (sommario):
Summary Conditional density estimation seeks to model the distribution of a response variable conditional on covariates. We propose a Bayesian partition model using logistic Gaussian processes to perform conditional density estimation. The partition takes the form of a Voronoi tessellation and is learned from the data using a reversible jump Markov chain Monte Carlo algorithm. The methodology models data in which the density changes sharply throughout the covariate space, and can be used to determine where important changes in the density occur. The Markov chain Monte Carlo algorithm involves a Laplace approximation on the latent variables of the logistic Gaussian process model which marginalizes the parameters in each partition element, allowing an efficient search of the approximate posterior distribution of the tessellation. The method is consistent when the density is piecewise constant in the covariate space or when the density is Lipschitz continuous with respect to the covariates. In simulation and application to wind turbine data, the model successfully estimates the partition structure and conditional distribution.
8
Zeng, Zilin, Hongjun Zhang, Rui Zhang e Youliang Zhang. "A Hybrid Feature Selection Method Based on Rough Conditional Mutual Information and Naive Bayesian Classifier". ISRN Applied Mathematics 2014 (30 marzo 2014): 1–11. http://dx.doi.org/10.1155/2014/382738.
Abstract (sommario):
We introduced a novel hybrid feature selection method based on rough conditional mutual information and Naive Bayesian classifier. Conditional mutual information is an important metric in feature selection, but it is hard to compute. We introduce a new measure called rough conditional mutual information which is based on rough sets; it is shown that the new measure can substitute Shannon’s conditional mutual information. Thus rough conditional mutual information can also be used to filter the irrelevant and redundant features. Subsequently, to reduce the feature and improve classification accuracy, a wrapper approach based on naive Bayesian classifier is used to search the optimal feature subset in the space of a candidate feature subset which is selected by filter model. Finally, the proposed algorithms are tested on several UCI datasets compared with other classical feature selection methods. The results show that our approach obtains not only high classification accuracy, but also the least number of selected features.
9
Dumedah, Gift, Aaron A. Berg e Mark Wineberg. "Pareto-optimality and a search for robustness: choosing solutions with desired properties in objective space and parameter space". Journal of Hydroinformatics 14, n. 2 (22 giugno 2011): 270–85. http://dx.doi.org/10.2166/hydro.2011.120.
Abstract (sommario):
Multi-objective genetic algorithms are increasingly being applied to calibrate hydrological models by generating several competitive solutions usually referred to as a Pareto-optimal set. The Pareto-optimal set comprises non-dominated solutions at the calibration phase but it is usually unknown whether all or only a subset of non-dominated solutions at the calibration phase remains non-dominated at the validation phase. In practice, users would like to know solutions (and their associated properties) which remain non-dominated at both the calibration and validation phases. This study investigates robustness of the Pareto-optimal set by developing a model characterization framework (MCF). The MCF uses cluster analysis to examine the distribution of solutions in parameter space and objective space, and conditional probability to combine linkages between the distributions of solutions in both spaces. The MCF has been illustrated for calibration output generated from application of the Non-dominated Sorting Genetic Algorithm-II to calibrate the Soil and Water Assessment Tool for streamflow in the Fairchild Creek watershed in southern Ontario. Our results show that not all non-dominated solutions found at the calibration phase perform the same for different validation periods. The MCF illustrates that robust solutions – non-dominated solutions which cluster in similar locations in parameter space and objective space – performed consistently well for several validation periods.
10
Gnad, Daniel, Jörg Hoffmann e Martin Wehrle. "Strong Stubborn Set Pruning for Star-Topology Decoupled State Space Search". Journal of Artificial Intelligence Research 65 (17 luglio 2019): 343–92. http://dx.doi.org/10.1613/jair.1.11576.
Abstract (sommario):
Analyzing reachability in large discrete transition systems is an important sub-problem in several areas of AI, and of CS in general. State space search is a basic method for conducting such an analysis. A wealth of techniques have been proposed to reduce the search space without affecting the existence of (optimal) solution paths. In particular, strong stubborn set (SSS) pruning is a prominent such method, analyzing action dependencies to prune commutative parts of the search space. We herein show how to apply this idea to star-topology decoupled state space search, a recent search reformulation method invented in the context of classical AI planning.
Star-topology decoupled state space search, short decoupled search, addresses planning tasks where a single center component interacts with several leaf components. The search exploits a form of conditional independence arising in this setting: given a fixed path p of transitions by the center, the possible leaf moves compliant with p are independent across the leaves. Decoupled search thus searches over center paths only, maintaining the compliant paths for each leaf separately. This avoids the enumeration of combined states across leaves.
Just like standard search, decoupled search is adversely affected by commutative parts of its search space. The adaptation of strong stubborn set pruning is challenging due to the more complex structure of the search space, and the resulting ways in which action dependencies may affect the search. We spell out how to address this challenge, designing optimality-preserving decoupled strong stubborn set (DSSS) pruning methods. We introduce a design for star topologies in full generality, as well as simpler design variants for the practically relevant fork and inverted fork special cases. We show that there are cases where DSSS pruning is exponentially more effective than both, decoupled search and SSS pruning, exhibiting true synergy where the whole is more than the sum of its parts. Empirically, DSSS pruning reliably inherits the best of its components, and sometimes outperforms both.
Tesi sul tema "Conditional Search Space":
1
Gamot, Juliette. "Algorithms for Conditional Search Space Optimal Layout Problems". Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILB042.
Abstract (sommario):
Cette thèse s'inscrit dans le cadre de l'optimisation d'agencement, une étape importante dans la conception de systèmes multidisciplinaires complexes tels que les véhicules aérospatiaux. Les problèmes d'agencement optimal (OLP) consistent à trouver la meilleure disposition d'un ensemble de composants dans un système ou un espace, afin d'atteindre certains objectifs (réduction des coûts, amélioration des performances, etc.) tout en satisfaisant diverses contraintes (géométriques, fonctionnelles, etc.). Le traitement des OLP est encore un défi aujourd'hui, tant en termes de formulation que de résolution. En effet, les OLP sont souvent très contraints et impliquent de nombreuses variables de décision (continues, discrètes, catégorielles), qui peuvent être fixes ou conditionnelles. Les variables conditionnelles sont utiles pour définir différents choix de conception qui doivent être faits en même temps que l'optimisation de l'agencement des composants. Ainsi, la résolution des OLP nécessite l'utilisation d'algorithmes d'optimisation avancés combinant différentes catégories de méthodes, comme par exemple les métaheuristiques et l'optimisation bayésienne.L'objectif global de la thèse est d'étudier les OLP, leur formulation dans différents contextes, leur résolution à l'aide de diverses méthodes d'optimisation et hybridations, ainsi que la validation de ces méthodes dans le cadre de la conception de véhicules aérospatiaux. Les contributions de la thèse sont organisées en deux parties correspondant à deux types d'OLP. Dans la première (respectivement deuxième) partie, la liste de composants à agencer est fixe (resp. variable), impliquant des OLP à espace de recherche fixe ou FSS-OLP, (resp. des OLP à espace de recherche conditionnel ou CSS-OLP). Dans les deux cas, le système/l'espace dans lequel les composants sont agencés est considéré comme mono ou multi-contenant.Dans la première partie, une étude des FSS-OLP est proposée, incluant leurs formulations génériques, leurs applications et méthodes de résolution, avec un focus particulier sur les méthodes quasi-physiques et les métaheuristiques. Basés sur un système de force virtuelle (VF), les algorithmes quasi-physiques simulent les lois de la dynamique et traitent efficacement les problèmes fortement contraints. Une variante (nommée CSO-VF) de de ces algorithmes est développée afin de résoudre les FSS-OLP à un seul contenant. Dans CSO-VF, la position et l'orientation des composants évoluent grâce au VF. Pour traiter les systèmes multi-contenants, CSO-VF est hybridé à un algorithme génétique (GA) dans un algorithme à deux étages qui affecte les composants aux contenants puis optimise leur disposition dans chacun des contenants. Ces deux algorithmes sont évalués grâce à des problèmes d'agencement de satellites.Dans la deuxième partie, une étude des CSS-OLP est proposée avec la même approche que dans la première partie. Les variables conditionnelles engendrent des OLP plus complexes. Par exemple, dans le contexte de la conception aérospatiale, une quantité donnée de carburant peut être incluse dans le système, soit dans un grand réservoir, soit dans deux plus petits. Par conséquent, le nombre de composants à positionner n'est pas le même dans les deux cas et le nombre de variables de conception et de contraintes varie donc au cours du processus d'optimisation. Deux approches ont été développées pour traiter les CSS-OLP à un seul contenant : la première est un GA modifié pour introduire des variables cachées dans les chromosomes. La seconde est une approche bi-niveaux combinant optimisation bayésienne et l'algorithme CSO-VF. L'optimisation bayésienne sélectionne les composants et CSO-VF optimise leur agencement. Cette dernière approche a été hybridée avec un GA dans un algorithme tri-niveaux afin de traiter les CSS-OLP multi-contenants. Enfin, tous les algorithmes sont évalués et comparés grâce à des problèmes d'agencement de satellitesThis thesis falls within the scope of layout optimization, which is an important stage in the design of complex multidisciplinary engineering systems such as aerospace vehicles. Optimal layout problems (OLPs) involve finding the best arrangement of a set of components within a single- or multi-container system or space to meet specific objectives (cost reduction, performance enhancement, etc.) while satisfying various constraints (geometrical, functional, etc.). Dealing with OLPs is challenging both in terms of their formulation and their efficient and effective resolution. Actually, OLPs are often highly constrained and involve many mixed decision variables (continuous, discrete/categorial) which may be fixed or conditional. Conditional variables are highly useful to define different design choices when the set of components to be arranged is variable and dynamic. Consequently, their resolution requires the use of advanced optimization algorithms combining different classes of (mixed-variable) methods including metaheuristics and Bayesian optimization.The overall objective of the thesis is to investigate OLPs, their formulation in different contexts, their resolution using various optimization methods and their hybridization, and their validation within the framework of aerospace vehicle design. The contributions of the thesis are organized in two parts corresponding to two types of OLPs. In the first (resp. second) part, the set of components to be arranged is fixed (variable or conditional) involving fixed search space OLPs or FSS-OLPs (resp. conditional search space OLPs or CSS-OLPs). In both cases, the system/space in which the components are arranged is considered single- or multi-container.In the first part, a survey of constrained mixed-variable FSS-OLPs is proposed including their generic formulations, applications and resolution methods with a particular focus on quasi-physical methods and population-based metaheuristics. Based on a virtual force system (VF) quasi-physical algorithms emulate the principle of physical laws in system dynamics and deal efficiently with highly constrained problems. A variant (namely CSO-VF) of these algorithms is devised for solving single-container FSS-OLPs. In CSO-VF, the positions and orientations of the components are evolved using VF. To deal with multi-container systems, CSO-VF is combined with a Genetic Algorithm (GA) in a two-stage algorithm that assigns the components to the containers and optimizes their layout. These single- and multi-container algorithms are assessed considering satellite module FSS-OLPs that are representative benchmarks.In the second part, a survey of constrained mixed-variable CSS-OLPs is proposed in the same way than in the first part. Conditional variables involve more complex OLPs. Actually, for instance, in the context of aerospace concept design, a given amount of fuel could be included in a container in either one large tank or two smaller ones. Therefore, as the number of components to position is not the same in both cases the number of design variables as well as constraint functions vary during the optimization process. To deal with single-container CSS-OLPs, two approaches have been investigated: the first one is a GA revisited considering hidden variables, leading to variable-geometry OLPs (in objective and constraint functions). The second approach is a two-stage surrogate guided-CSO-VF algorithm combining Bayesian Optimization with CSO-VF. Bayesian Optimization selects the components with are considered by CSO-VF for layout optimization. This latter approach has been extended with a GA in a three-stage algorithm to tackle multi-container CSS-OLPs. Finally, all the algorithms are evaluated and compared based on their application to CSS variants of satellite module OLPs
2
Czajkowska, Anna Marzena. "Maximum entropy based evolutionary optimization of water distribution networks under multiple operating conditions and self-adaptive search space reduction method". Thesis, University of Strathclyde, 2016. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=27497.
Libri sul tema "Conditional Search Space":
1
Severin, Timothy. The Spice Islands voyage: In search of Wallace. London: Little, Brown, 1997.
2
Daley, Patricia. Gender & genocide in Burundi: The search for spaces of peace in the Great Lakes Region. Oxford: James Currey, 2007.
3
Brindza, Ján, e Olga Grygorieva, a cura di. Book of Abstracts of the 5th International Scientific Conference Agrobiodiversity for Improving the Nutrition, Health, Quality of Life and Spiritual Human Development. Slovak University of Agriculture in Nitra, Slovakia, 2021. http://dx.doi.org/10.15414/2021.9788055224015.
Abstract (sommario):
International conference aims to create more space and conditions for a broader discussion and search for all available solutions for the conservation and use of agrobiodiversity within the possibilities that research teams in individual countries and workplaces have. Research teams usually focus only on solving a specific biological problem of a plant species. That's right. But it would be appropriate for research teams to go beyond the research barriers and connect research results to practical applications, conditions and current societal challenges not only to improve nutrition, health and quality of life, but also to areas related to spiritual human development, and of humankind.Therefore, the conference organizers included in the program lectures focused on ethics in biological research, the use of plant species and nature for human healing, the use of agroforestry systems for food production with the current solution of adverse climate change, practical use of plants for new therapy and rehabilitation of humans and other specific and unusual areas.
4
Kirichenko, Alexander. Greek Literature and the Ideal. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/oso/9780192866707.001.0001.
Abstract (sommario):
Abstract The contention of this book is that the development of Greek literature was motivated by the need to endow political geography with a sense of purposeful structure. It views Greek literature as a crucial factor in the cultural production of space and Greek geography as a crucial factor in the production of literary meaning. Its focus is on the idealizing images that Greek literature created of three spatial patterns of power distribution—a decentralized network of aristocratically governed communities (archaic Greece), a democratic city controlling an empire (classical Athens), and a microcosm of Greek culture located on foreign soil, ruled by quasi-divine royals, and populated by immigrants (Ptolemaic Alexandria). The book draws connections between the formation of these idealizing images and the emergence of such literary modes of meaning-making as the authoritative communication of the truth, the dialogic encouragement to search for the truth on one’s own, and the abandonment of transcendental goals for the sake of cultural memory and/or aesthetic pleasure. Its readings of such canonical Greek authors as Homer, Hesiod, the tragedians, Thucydides, Plato, Callimachus, and Theocritus show that the pragmatics of Greek literature (the sum total of the ideological, cognitive, and emotional effects that it seeks to produce) is, in essence, always a pragmatics of space—i.e. that there is a strong correlation between the historically conditioned patterns of political geography and the changing mechanisms whereby Greek literature enabled its recipients to make sense of their world.
5
Vogt, Wendy A. Lives in Transit. University of California Press, 2018. http://dx.doi.org/10.1525/california/9780520298545.001.0001.
Abstract (sommario):
Propelled by structural conditions of violence and everyday insecurity, each year tens of thousands of people from Guatemala, Honduras and El Salvador leave their homes in search of a more secure future. For those en route to the United States, they must first cross Mexico where transnational and state security regimes funnel them into clandestine routes where they encounter abuse, injury, extortion, police profiling, sexual violence and kidnapping. As unauthorized gendered and racialized others, migrants become implicated within a state-criminal nexus that profits from their plight. Moving beyond scholarship focused on fixed sending and receiving communities or borderlands, Lives in Transit focuses on the liminal spaces between these zones as crucial sites of ethnographic analysis to understand the complexity of contemporary mobilities and the ways structural forms of violence are rearticulated at the local level. Through the powerful testimonies of migrants still in the midst of their journeys and the people on the ground who care for them, this book provides a rare look into the everyday and often gendered logics of mobility, violence, security and intimacy within spaces of transit. From the intimate perspective of daily life in migrant shelters and local communities, it illuminates the strategies, social relations and economies of care that people engage as they negotiate their movements and their lives. It also bears witness to the emerging social movement around migrant rights that connects the intimate labors of individuals and families between and across borders.
6
Aspden, Richard, e Jenny Gregory. Morphology. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199668847.003.0011.
Abstract (sommario):
The study of joint morphology can help us to understand the risk factors for osteoarthritis (OA), how it progresses, and aids in developing imaging biomarkers for study of the disease. OA results in gross structural changes in affected joints. Growth of osteophytes, deformation of joint components, and loss of joint space where cartilage has broken down are all characteristics of the disorder. Certain bone shapes as well as malalignment predispose people to future OA, or may be a marker for early OA. Geometrical measures, such as the alpha angle or Wiberg’s CE angle, used to be the primary tool for investigating morphology. In recent years, however, statistical shape modelling (SSM) has become increasingly popular. SSM can be used with any imaging modality and has been successfully applied to a number of musculoskeletal conditions. It uses sets of landmark points denoting the anatomy of one or more bones to generate new variables (modes) that describe and quantify the shape variation in a set of images via principal components analysis. With the aid of automated search algorithms for point placement, the use of SSMs is expanding and provides a valuable and versatile tool for exploration of bone and joint morphometry. Whilst the majority of research has focused on hip and knee OA, this chapter provides an overview of joint morphology through the whole skeleton and how it has helped our ability to understand and quantify the risk and progression of osteoarthritis.
Capitoli di libri sul tema "Conditional Search Space":
1
Bu, Lei, Zhunyi Xie, Lecheng Lyu, Yichao Li, Xiao Guo, Jianhua Zhao e Xuandong Li. "BRICK: Path Enumeration Based Bounded Reachability Checking of C Program (Competition Contribution)". In Tools and Algorithms for the Construction and Analysis of Systems, 408–12. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-99527-0_22.
Abstract (sommario):
AbstractBRICK is a bounded reachability checker for embedded C programs. BRICK conducts a path-oriented style checking of the bounded state space of the program, that enumerates and checks all the possible paths of the program in the threshold one by one. To alleviate the path explosion problem, BRICK locates and records unsatisfiable core path segments during the checking of each path and uses them to prune the search space. Furthermore, derivative free optimization based falsification and loop induction are introduced to handle complex program features like nonlinear path conditions and loops efficiently.
2
Ferreira, Margarida, Miguel Terra-Neves, Miguel Ventura, Inês Lynce e Ruben Martins. "FOREST: An Interactive Multi-tree Synthesizer for Regular Expressions". In Tools and Algorithms for the Construction and Analysis of Systems, 152–69. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-72016-2_9.
Abstract (sommario):
AbstractForm validators based on regular expressions are often used on digital forms to prevent users from inserting data in the wrong format. However, writing these validators can pose a challenge to some users.We present Forest, a regular expression synthesizer for digital form validations. Forest produces a regular expression that matches the desired pattern for the input values and a set of conditions over capturing groups that ensure the validity of integer values in the input. Our synthesis procedure is based on enumerative search and uses a Satisfiability Modulo Theories (SMT) solver to explore and prune the search space. We propose a novel representation for regular expressions synthesis, multi-tree, which induces patterns in the examples and uses them to split the problem through a divide-and-conquer approach. We also present a new SMT encoding to synthesize capture conditions for a given regular expression. To increase confidence in the synthesized regular expression, we implement user interaction based on distinguishing inputs.We evaluated Forest on real-world form-validation instances using regular expressions. Experimental results show that Forest successfully returns the desired regular expression in 70% of the instances and outperforms Regel, a state-of-the-art regular expression synthesizer.
3
Mieli, Micol. "Exploring “Planned Serendipity” and On-site Information Behavior on Smartphones". In Information and Communication Technologies in Tourism 2022, 406–11. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-94751-4_36.
Abstract (sommario):
AbstractThe paper explores tourists’ smartphone-related information behavior on site in light of the concept of “planned serendipity”. The ability to gather information at anytime and anywhere can deeply influence tourists’ behavior, their information needs and the outcomes of their travel plans. In this study, the concept of planned serendipity is used to suggest that the outcome of travel information behavior on site is not entirely planned nor entirely serendipitous. The study employs the Experience Sampling Method (ESM) in combination with qualitative interviews, which allow the researcher to gather data both during the participants’ trip and afterwards. The thematic analysis resulted in four main themes related to information search connected to smartphone use: flexible plans; orientation in time and space; specificity of the query; aiming for optimization. Such conditions result in planned serendipity. The study thus contributes to the conceptualization of planned serendipity as an outcome of smartphone use during travel for information purposes.
4
Zhang, Qi, Linxue Li, Nan Ma, Yunxiang Shan e William W. Braham. "Characterizing the Solution Space of Building Shading System Through Computational and Parametric Feed-Forward Design Approach". In Computational Design and Robotic Fabrication, 284–94. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-99-8405-3_24.
Abstract (sommario):
AbstractBuilding shading systems play an important role in controlling solar heat gains, which can mitigate the impact of climate change on indoor environment. Effectively reducing cooling demand in summer and heating demand in winter requests further development of seasonally regulated shading systems. The main problem is to find a way that consumes less energy while reaching better comfort, which demonstrates potential for conducting an extensive search to parametrize configuration of shading. This paper aims to investigate the effects of building shading systems on energy and thermal performance in different seasonal conditions through a parametric design method, using Baoshan station in Shanghai, China as a case study to establish a baseline model and test different shading components’ direction, depth, spacing, and tilt angle. The method explores a large solution space at the beginning of design, establishing a variety of approaches that can inform the architectural design team. The results showed that a proper passive shading system can reduce energy consumption by about 13% while thermal comfort meets ASHRAE 55 standards. This finding indicates the possibility of improving the indoor thermal comfort while lessening building energy consumption.
5
Daberkow, Andreas, Stephan Groß, Christopher Fritscher e Stefan Barth. "An Energy Efficiency Comparison of Electric Vehicles for Rural–Urban Logistics". In Small Electric Vehicles, 85–96. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-65843-4_7.
Abstract (sommario):
AbstractIn many small and medium-sized businesses in rural–urban areas, delivery services to and from customers, suppliers, and distributed locations are required regularly. In contrast to purely urban commercial centres, the distances here are larger. The aim of this paper is to identify opportunities for substituting combustion-engine logistics with lightweight electric commercial vehicles and the limitations thereto, describing an energy efficiency comparison and improvement process for a defined logistics application. Thus, the area of Heilbronn-Franconia and its transport conditions are presented as examples to compare the use case to standard driving cycles. Then the logistic requirements of Heilbronn UAS (University of Applied Science) locations and the available vehicles as well as further electric vehicle options are depicted. Options are discussed for the additional external payload in search of transport volume optimisation without increasing the vehicle floor space. To this end, simulation models are developed for the aerodynamic examination of the enlarged vehicle body and for determining energy consumption. Consumption and range calculation lead to vehicle concept recommendations. These research activities can contribute to the transformation of commercial electro mobility in rural and urban areas in many parts of Germany and Europe.
6
Tàbara, J. David. "The TIPPING+ Project Journey". In Springer Climate, 1–19. Cham: Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-50762-5_1.
Abstract (sommario):
AbstractThis chapter introduces and provides the research background of the several contributions of this book. It does so first by briefly reviewing the previous conceptual developments that over the course of two decades eventually led to the EU-funded project TIPPING+. The goal of the project was to improve our understanding of the enabling conditions and complex processes for fast structural sustainable transformations in coal and carbon intensive regions (CCIRs) using the notion of positive tipping points as a boundary concept able to bring together the insights of various social science and interdisciplinary perspectives. The main challenge facing these regions is understood not only as sectoral energy transitioning challenge; but the extent to which multiple socio-economic, political and cultural dimensions for full-systems transformations are taken into account. Second, it presents some of the conceptual and methodological proposals generated by the project and argues for ontological and epistemological diversity and to understand equity and justice as a key drivers and outcomes of positive tipping points. As a research journey, however, the TIPPING+ project did not search for a destination. Instead, it looked for a point of departure, for an opportunity space in which different disciplines, researchers and interests could jointly develop their own ideas and start their own new research ventures.
7
Dobrocky, Tomas, e Àlex Rovira. "Problem Solving Disorders of CSF". In IDKD Springer Series, 13–27. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-50675-8_2.
Abstract (sommario):
AbstractSpontaneous Intracranial Hypotension (SIH)Spontaneous intracranial hypotension (SIH) is a debilitating medical condition, which is perpetuated by the continuous loss of cerebrospinal fluid (CSF) at the level of the spine, and is the top differential diagnosis for patients presenting with orthostatic headache. Neuroimaging plays a crucial role in the diagnostic work-up and monitoring SIH, as it provides objective data in the face of various clinical symptoms and very often a normal opening pressure on lumbar puncture. Brain MRI frequently demonstrates typical signs of CSF depletion and includes homogenous dural enhancement, venous distention, subdural collections, and brain sagging. Three types of CSF leaks may be distinguished: (1) ventral dural leaks due to microspurs, (2) leaking spinal nerve root cysts, (3) or direct CSF venous fistula. The quest for the leak may be the fabled search for the needle in the haystack, scrutinizing the entire spine for a dural breach often the size of pin. The main role of spine imaging is the correct classification and precise localization of CSF leaks. Precise localization of the CSF leak site is crucial to successful treatment, which is generally a targeted percutaneous epidural patch or surgical closure when conservative measures fail to provide long-term relief.Obstructive Hydrocephalus. Communicating Hydrocephalus. Normal Pressure HydrocephalusModern imaging techniques play an essential role for understanding of the anatomy of the cerebrospinal fluid (CSF) spaces and ventricular system, as well as the hydrodynamics of CSF flow, and consequently in the assessment of the different types of hydrocephalus. Obstructive (non-communicating) hydrocephalus is a complex disorder resulting from an obstruction/blockage of the CSF circulation along one or more of the narrow apertures connecting the ventricles, being the most common type of hydrocephalus in children and young adults. On the other hand, communicating hydrocephalus is defined as a cerebrospinal fluid flow circulation abnormality outside the ventricular system that produces an increase in the ventricular size. Most cases are secondary to obstruction of CSF flow between the basal cisterns and brain convexity and include common conditions such as subarachnoid hemorrhage and meningitis (infectious and neoplastic). In a subset of communicating hydrocephalus, no CSF obstruction can be demonstrated as occurs in normal pressure hydrocephalus (NPH), a complex entity with poorly understood cerebrospinal fluid dynamics. Neuroradiology plays an essential role in the diagnosis of hydrocephalus, and in distinguishing this condition from other causes of ventriculomegaly.
8
Lantican, Gaudencia A. "Field Screening of Gamma-Irradiated Cavendish Bananas". In Efficient Screening Techniques to Identify Mutants with TR4 Resistance in Banana, 97–109. Berlin, Heidelberg: Springer Berlin Heidelberg, 2022. http://dx.doi.org/10.1007/978-3-662-64915-2_7.
Abstract (sommario):
AbstractIn our search for Cavendish bananas to withstand Fusarium oxysporum f. sp. cubense (Foc TR4) and other diseases, field screening of tissue-cultured Grand Nain banana seedlings derived from gamma-irradiated shoot tips was explored. Six months after irradiation and multiplication in the laboratory, the plantlets (M1V6) were individually grown in seedling bags under screen house conditions for 8 weeks, side-by-side with non-irradiated plantlets of the same clone. Once acclimatized, the banana plants were grown in an area confirmed positive of Foc TR4 (based on previous farm records stating that more than 50% of the plant population succumbed to the disease). Seedlings from each treatment (dose of radiation) were divided into four replicates, regardless of the number of plants. Each plant was given a unique identification code for traceability during disease monitoring, bunch and fruit quality evaluation.Incidences of Foc TR4, Moko disease (Ralstonia solanacearum) and virus diseases were monitored weekly. Plants found positive of any disease were eradicated immediately. The plant population for the succeeding generation was managed by removing the unwanted suckers, 12 weeks from planting using a spade gouge and keeping only one sucker per plant for the next generation. Agronomic characters of each plant were taken at the flowering stage. These included age to flower, height, pseudostem circumference, number of leaves and height of the sucker. The bunch was harvested 12 weeks from flowering. The number of hands in a bunch, the number of fingers and weight of a hand were recorded. The same agronomic characters of the plant were taken for the succeeding generations.Plants left standing in the field without any disease symptoms 3 years after planting were considered as putative mutants and were selected as candidate lines for multiplication and second-generation field screening. Only healthy suckers (free from viruses) were further multiplied via tissue culture technique to reach M1V6. Clean suckers from each line free of soil debris or dirt were sent to the laboratory for multiplication. At least 1000 plantlets were produced from each line for the second-generation field screening. These were grown in two locations – with and without records of Foc TR4. Field monitoring activities including plant population management, disease incidence assessment and fruit quality evaluation were carried out following the same protocols used in the establishment of the first-generation plants. Lines with population showing ≤10% Foc TR4 after the first harvest, with good vigor, fruit quality and productivity were considered as candidates for further multiplication, farmers distribution and field planting under semi-commercial scale.
9
Chi, Yuhong, Fuchun Sun, Langfan Jiang, Chunyang Yu e Chunli Chen. "Quotient Space-Based Boundary Condition for Particle Swarm Optimization Algorithm". In Advances in Abstract Intelligence and Soft Computing, 31–42. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-2651-5.ch003.
Abstract (sommario):
To control particles to fly inside the limited search space and deal with the problems of slow search speed and premature convergence of particle swarm optimization algorithm, this paper applies the theory of topology, and proposed a quotient space-based boundary condition named QsaBC by using the properties of quotient space and homeomorphism. In QsaBC, Search space-zoomed factor and Attractor are introduced according to the dynamic behavior and stability of particles, which not only reduce the subjective interference and enforce the capability of global search, but also enhance the power of local search and escaping from an inferior local optimum. Four CEC’2008 benchmark functions are selected to evaluate the performance of QsaBC. Comparative experiments show that QsaBC can achieve the satisfactory optimization solution with fast convergence speed. Furthermore, QsaBC is more effective with errant particles, and has easier calculation and better robustness than other methods.
10
Barrow, John D. "Initial Conditions". In New Theories of Everything, 44–92. Oxford University PressNew York, NY, 2007. http://dx.doi.org/10.1093/oso/9780192807212.003.0003.
Abstract (sommario):
Abstract Laws of Nature tell us how things change. Yet behind them we believe there to lurk invariances that straitjacket reality. Nature can do whatever she pleases so long as these charmed quantities stay the same throughout the change. The Theory of Everything seeks to provide us with the ultimate directory of all possible changes. The guiding principle in the search for this all-controlling formula is that it must be a single law, not a collection of different pieces. The logical unity of the Universe demands a single invariance that remains unchanged in the face of all the complexity and transience we see about us from the smallest sub-atomic scales to the farthest reaches of outer space.
Atti di convegni sul tema "Conditional Search Space":
1
Valdez, Sofia, Nicholas Rodriguez e Carolyn Seepersad. "Latent Variable Representations for Interactive Structural Design Exploration". In ASME 2022 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/detc2022-91076.
Abstract (sommario):
Abstract Additive manufacturing and topology optimization are complementary technologies that enable unprecedented levels of design freedom for realizing complex structures. This increasing design freedom is accompanied by increasing complexity, such that it can become difficult for either computational algorithms or human designers alone to search these expansive design spaces effectively. Our previous work laid the foundation for an interactive design framework that enables human designers to use their expertise and intuition to guide computational algorithms quickly towards promising solutions. The framework established a latent representation of a library of designs by combining classical topology optimization techniques with a conditional generative adversarial network (cGAN). Our goal is to expand on this framework by creating interactive functionalities that allow users to more efficiently visualize and search an expansive structural design space by manipulating its latent variable representation.
2
Drobyshevski, Y., H. Wadhwa e J. R. Whelan. "Response Based Design Metocean Conditions for an FPSO by the Extremum Search Within Joint Metocean PDF". In ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/omae2015-41658.
Abstract (sommario):
The response based analysis of a floating system aims at the prediction of extreme N-year return period responses by analysing their statistics in site-specific metocean conditions. After the extreme responses have been determined the inverse problem is solved: the most probable design metocean conditions (DMC) should be determined which cause these responses. The most probable DMC associated with a given response can be determined by using the joint probability density function (PDF) of metocean parameters. Mathematically, the most probable DMC is equivalent to a “design point”, at which the joint metocean PDF has a conditional maximum. This paper presents a method for finding the most probable DMC by the extremum search. Several numerical examples are presented to demonstrate finding the most probable DMCs for typical responses of an FPSO in North Sea environment, including global motions, wave loads, turret motions and relative wave motions. The most probable DMCs are found by the search process implemented in the space of physical metocean variables, which allows for easy interpretation of the results and exploring the response sensitivity to variability of metocean parameters.
3
Shi, Qinzhong, Ichiro Hagiwara e Futoshi Takashima. "The Most Probable Optimal Design Method for Global Optimization". In ASME 1999 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/detc99/dac-8635.
Abstract (sommario):
Abstract In this study, to find the global optimum efficiently, holographic neural network is introduced to be an activate function of response surface methodology. Since the accuracy of approximation function near the global optimal design is merely important, techniques to search the region of containing the global optimal design using conditional random seeds, and techniques for finding more, accurate approximation near the global optimal design, using holographic neural network are exploited. In the study, the proposed approach called the most probable optimal design (MPOD) method to pick up one local optimum design which has the biggest probability in the design space. Design example of crash worthiness for the passenger injury with continuous and discrete design variables are shown the validity of the method.
4
Meshreki, Mouhab, Karim Hamza, Ashraf O. Nassef e Helmi Attia. "Optimization of the Cutting Conditions for High Speed Drilling of Woven Composites". In ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/detc2013-12992.
Abstract (sommario):
The present work proposes a new algorithm for the optimization of cutting parameters in the high speed drilling of woven composites. The cutting parameters under consideration are the feed rate and the spindle speed. Three performance parameters are to be minimized. These are the exit delamination, the surface roughness and the thrust force. These performance parameters are observed experimentally. One of the challenges that face the experimental testing of these parameters is the high cost of the drilling tools and specimen materials. Therefore, the minimization of the number of experimental tests is a necessary requirement. The algorithm presented hybridizes Kriging as a meta-modeling technique with evolutionary multi-objective optimization to optimize the cutting parameters while intelligently selecting the new set of cutting parameters in each iteration. After starting with a factorial design of the search space, and after testing the performance criteria at these points, the algorithm fits a multi-dimensional surface using Kriging. This step is followed by an evolutionary search on the fitted model. The search spreads a population of search points in the direction of better performance criteria as well as in the direction of un-sampled space. The previous two steps are conducted iteratively for a pre-defined number of iterations. In the final iteration, the population of search points is clustered to yield a small number of new points at which the new experiments will be conducted. The whole process is iterated until the maximum number of allowable experiments is achieved. The algorithm is tested using an existing set of previously published experimental data that are dense enough to predict the actual response surface of the performance criteria. Results showed that the algorithm smartly moved into the direction of higher performance criteria with a low number of experimental trials.
5
Dong, Ming, e Jianzhong Cha. "Timed Petri Nets and Heuristic Search-Based FMS Scheduling". In ASME 1996 Design Engineering Technical Conferences and Computers in Engineering Conference. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-detc/dac-1063.
Abstract (sommario):
Abstract In this paper, FMS scheduling problems are modeled by timed Petri nets. The timed Petri nets can model the important characteristics of FMSs such as routing flexibility, shared resources, precedence relationships among operations, concurrency, synchronization and lot sizes. So the Petri net model of an FMS scheduling problem which reflects the given constraints would limit the search within the feasible schedule space. By making use of a heuristic scheduling algorithm which satisfies the lower bound condition of the algorithm A*, the search space can be further reduced and an optimal path can be found. This new scheduling approach which combines Petri net modeling with heuristic search can effectively handle with the structural complexity and computational complexity of FMS scheduling problems.
6
Blümer, Mariana Piovan. "A porosidade no largo da batata: cultura como patrimônio imaterial na cidade contemporânea". In Seminario Internacional de Investigación en Urbanismo. Barcelona: Curso de Arquitetura e Urbanismo. Universidade do Vale do Itajaí, 2016. http://dx.doi.org/10.5821/siiu.6299.
Abstract (sommario):
O Largo da Batata torna-se objeto de estudo na busca pela compreensão da Porosidade na cidade como condicionante de ocupação e uso dos espaços públicos pelo ser humano, assim como estepróprio se construindo a partir de experiências possíveis por imersão nessa esfera.O espaço público identificado como um espaço de significações, constituído por camadas que denotam as transformações do sentido delugar. Nesse contexto, os poros são indiretamente percebidos, pois não são possíveis de serem interpretados apenas pelas formas físicas (visuais). Trata-se de uma análise fenomenológica das formas de ocupação atuais somadas às dinâmicas de uso e identidade desse lugar ao longo do tempo, as quais são entendidas aqui como membranas.Investiga-se, portanto, quais são os parâmetros que definem a porosidade? Há relação entre as condicionantes de porosidade física e de porosidade social? Como elas qualificam os espaços urbanos públicos no cotidiano citadino (espaço existencial)? É possível construir porosidade? The Largo da Batata becomes an object of study in the search for understanding porosity in the city as a condition of occupation and use of public spaces by man, and man self-buildingfrom possible experiences for immersion in this sphere. Public space hasidentified as space of meanings, made of layers that denote the transformations on the sense of place. In this context, the pores are indirectly perceived as they are not able to be interpreted only by the physical forms (visual); this is a phenomenological analysis of modes of today’s occupation, the dynamics of use and identity of this place throughout its history - understood here as their membranes. Therefore, we inquire what are the parameters that define the porosity? Is there a relationship between the conditions of physical porosity and social porosity? If so, how they qualify the public urban spaces in the daily city (existential space)? Can we build porosity?
7
Shahriari, A., H. Mokhlis, A. H. A. Bakar, M. Karimi, J. A. Laghari e M. Kazeminezad. "The calculation of low voltage solution based on state space search method in ill-conditioned system". In 2012 IEEE International Power Engineering and Optimization Conference (PEOCO). IEEE, 2012. http://dx.doi.org/10.1109/peoco.2012.6230836.
8
Khalessi, M. R., Y. T. Wu e T. Y. Torng. "Most-Probable-Point-Locus Reliability Method in Standard Normal Space". In ASME 1991 Design Technical Conferences. American Society of Mechanical Engineers, 1991. http://dx.doi.org/10.1115/detc1991-0003.
Abstract (sommario):
Abstract This paper describes a new structural reliability analysis iteration procedure based on the concept of most probable point locus (MPPL). Using a new quadratic search algorithm, the proposed procedure examines the global behavior of the limit-state function, g, along the MPPL in the standard normal space in search of the most probable point (MPP) on the g = o surface, and identifies unusual conditions such as multiple MPPs. During the iteration procedure, the generated information is updated after each sensitivity analysis. This action helps the analyst to minimize the number of computer runs and determine the next step. By adopting two efficient convergence criteria, the proposed procedure is demonstrated to be significantly more efficient than the commonly used reliability analysis procedures, and is suitable to be integrated with existing general-purpose finite element computer programs for nondeterministic structural analysis.
9
Pisu, Pierluigi, C. Hubert, N. Dembski, G. Rizzoni, John Josephson, James Russell e Mark Carroll. "Modeling and Design of Heavy Duty Hybrid Electric Vehicles". In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81514.
Abstract (sommario):
A large scale design space exploration provides invaluable insight into vehicle design tradeoffs. Performing such a search requires designers to: • define appropriate performance criteria by which to judge the vehicles in the design space; • develop vehicle models to calculate the needed criteria; and • determine suitable velocity profiles as well as grade and terrain conditions to feed into the models. This paper presents a methodology for creating and conducting a design space exploration with particular application to heavy duty series hybrid electric-trucks.
10
Venkatesh, Jayantheeswar, Anders Thorin e Mathias Legrand. "Nonlinear Modal Analysis of a One-Dimensional Bar Undergoing Unilateral Contact via the Time-Domain Boundary Element Method". In ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/detc2017-68340.
Abstract (sommario):
Finite elements in space with time-stepping numerical schemes, even though versatile, face theoretical and numerical difficulties when dealing with unilateral contact conditions. In most cases, an impact law has to be introduced to ensure the uniqueness of the solution: total energy is either not preserved or spurious high-frequency oscillations arise. In this work, the Time Domain Boundary Element Method (TD-BEM) is shown to overcome these issues on a one-dimensional system undergoing a unilateral Signorini contact condition. Unilateral contact is implemented by switching between free boundary conditions (open gap) and fixed boundary conditions (closed gap). The solution method does not numerically dissipate energy unlike the Finite Element Method and properly captures wave fronts, allowing for the search of periodic solutions. Indeed, TD-BEM relies on fundamental solutions which are travelling Heaviside functions in the considered one-dimensional setting. The proposed formulation is capable of capturing main, subharmonic as well as internal resonance backbone curves useful to the vibration analyst. For the system of interest, the nonlinear modeshapes are piecewise-linear unseparated functions of space and time, as opposed to the linear modeshapes that are separated half sine waves in space and full sine waves in time.
Rapporti di organizzazioni sul tema "Conditional Search Space":
1
Weinschenk, Craig. Analysis of Search and Rescue Tactics in Single-Story Single-Family Homes Part I: Bedroom Fires. UL's Fire Safety Research Institute, maggio 2022. http://dx.doi.org/10.54206/102376/dptn2682.
Abstract (sommario):
Prior full-scale fire service research on the residential fireground has focused the impact of ventilation and suppression tactics on fire dynamics. This study builds upon prior research by conducting 11 experiments a purpose-built single-story, single-family residential structure to quantify the im- pact of how search and rescue tactics are coupled with ventilation and suppression actions and timing. Each fully furnished structure included four bedrooms, 2 bathrooms and an open-floor kitchen and living room. The structures were instrumented to quantify post-ignition toxic gas and thermal conditions. Temperature, velocity, and pressure were measured to evaluate the fire dynamics. Gas concentrations and heat fluxes were measured to quantify toxic and thermal exposures. Across this series of experiments, the impact of isolation of fire and non-fire compartments, the timing of search actions relative to suppression actions, and the influence of isolation, elevation, and path of travel during rescue were examined with respect to firefighter safety and occupant tenability. Similar to previous experiments in both purpose-built and acquired structure, the data showed that prior intervention locations lower in elevation and/or behind closed doors had lower toxic gas and thermal exposures compared to locations at higher elevations or locations that were not isolated. Lower elevations were also shown to have lower toxic gas and thermal exposures during the removal of occupants as part of rescue operations. For scenarios where search operations occurred prior to suppression, isolation of spaces from flow paths connected to the fire compartment was shown to be effective at reducing the thermal operating class for firefighters and the toxic and thermal exposure rates compared to spaces that were not isolated. Following isolation, exterior ventilation was found to further reduce the toxic gas and thermal exposures in the protected space. Suppression, from either interior and exterior positions, was effective at reducing the thermal operating class for searching firefighters and the rate of thermal exposure increase to occupants. Following suppression, additional exterior ventilation increased the rate at which gas concentrations returned to pre-ignition levels.
2
Weinschenk, Craig, e Jack Regan. Analysis of Search and Rescue Tactics in Single-Story Single-Family Homes Part II: Kitchen and Living Room Fires. UL's Fire Safety Research Institute, maggio 2022. http://dx.doi.org/10.54206/102376/zkxw6893.
Abstract (sommario):
Prior full-scale fire service research on the residential fireground has focused the impact of ventilation and suppression tactics on fire dynamics. This study builds upon prior research by conducting 10 experiments a purpose-built single-story, single-family residential structure to quantify the im- pact of how search and rescue tactics are coupled with ventilation and suppression actions and timing. Each fully furnished structure included four bedrooms, 2 bathrooms and an open-floor kitchen and living room. The structures were instrumented to quantify post-ignition toxic gas and thermal conditions. Temperature, velocity, and pressure were measured to evaluate the fire dynamics. Gas concentrations and heat fluxes were measured to quantify toxic and thermal exposures. Across this series of experiments, the impact of isolation of fire and non-fire compartments, the timing of search actions relative to suppression actions, and the influence of isolation, elevation, and path of travel during rescue were examined with respect to firefighter safety and occupant tenability. Similar to previous experiments in both purpose-built and acquired structure, the data showed that prior intervention locations lower in elevation and/or behind closed doors had lower toxic gas and thermal exposures compared to locations at higher elevations or locations that were not isolated. Lower elevations were also shown to have lower toxic gas and thermal exposures during the removal of occupants as part of rescue operations. For scenarios where search operations occurred prior to suppression, isolation of spaces from flow paths connected to the fire compartment was shown to be effective at reducing the thermal operating class for firefighters and the toxic and thermal exposure rates compared to spaces that were not isolated. Following isolation, exterior ventilation was found to further reduce the toxic gas and thermal exposures in the protected space. Suppression, from either interior and exterior positions, was effective at reducing the thermal operating class for searching firefighters and the rate of thermal exposure increase to occupants. Following suppression, additional exterior ventilation increased the rate at which gas concentrations returned to pre-ignition levels.
3
Weinschenk, Craig, e Keith Stakes. Analysis of Search and Rescue Tactics in Single-Story Single-Family Homes Part III: Tactical Considerations. UL's Fire Safety Research Institute, maggio 2022. http://dx.doi.org/10.54206/102376/xsla7995.
Abstract (sommario):
Prior full-scale fire service research on the residential fireground has focused the impact of ventilation and suppression tactics on fire dynamics. This study builds upon prior research by conducting 21 experiments in two identical purpose-built single-story, single-family residential structures to quantify the impact of how search and rescue tactics are coupled with ventilation and suppression actions and timing. Each fully furnished structure included four bedrooms, 2 bathrooms and an open-floor kitchen and living room. The structures were instrumented to quantify post-ignition toxic gas and thermal conditions. Temperature, velocity, and pressure were measured to evaluate the fire dynamics. Gas concentrations and heat fluxes were measured to quantify toxic and thermal exposures. Eleven experiments examined bedroom fires, eight examined kitchen fires, and two examined living room fires. Across this series of experiments, the impact of isolation of fire and non-fire compartments, the timing of search actions relative to suppression actions, and the influence of isolation, elevation, and path of travel during rescue were examined with respect to firefighter safety and occupant tenability. Similar to previous experiments in both purpose-built and acquired structure, the data showed that prior intervention locations lower in elevation and/or behind closed doors had lower toxic gas and thermal exposures compared to locations at higher elevations or locations that were not isolated. Lower elevations were also shown to have lower toxic gas and thermal exposures during the removal of occupants as part of rescue operations. For scenarios where search operations occurred prior to suppression, isolation of spaces from flow paths connected to the fire compartment was shown to be effective at reducing the thermal operating class for firefighters and the toxic and thermal exposure rates compared to spaces that were not isolated. Following isolation, exterior ventilation was found to further reduce the toxic gas and thermal exposures in the protected space. Suppression, from either interior and exterior positions, was effective at reducing the thermal operating class for searching firefighters and the rate of thermal exposure increase to occupants. Following suppression, additional exterior ventilation increased the rate at which gas concentrations returned to pre-ignition levels.
4
Kerber, Steve, e Robin Zevotek. Fire Service Summary Report: Study of Residential Attic Fire Mitigation Tactics and Exterior Fire Spread Hazards on Firefighter Safety. UL Firefighter Safety Research Institute, novembre 2014. http://dx.doi.org/10.54206/102376/pxtq2256.
Abstract (sommario):
Attic fires pose many hazards for the fire service. When a fire occurs in an attic, it is common it goes unnoticed/reported until smoke or flames are visible from the outside of the structure. Because they take longer to detect, attic fires are more dangerous for firefighters and residents. In a fire situation, the attic ventilation system, which is designed to reduce moisture accumulation by drawing fresh air low from the eaves and exhausting moisture laden warm air near the peak, create an optimal fire growth and spread situation by supplying oxygen to the fire and exhausting hot gases. An estimated 10,000 residential attic fires are reported to U.S. fire departments each year and cause an estimated 30 civilian deaths, 125 civilian injuries and $477 million in property loss. The location of the attic creates several difficulties for the fire service. Firefighters must decide whether to fight the fire from inside the structure, from the outside or a combination of the two. This the decision is complicated by the constant hazard of ceiling collapse, which has the potential to rapidly deteriorate conditions in the living spaces. A piece of gypsum board may fall or be pulled from the ceiling making the relatively clear and cool conditions in the living space change very quickly endangering firefighters executing a search and rescue operation as part of their life safety mission. Further complicating the decision are the hazards associated with roof structure collapse, creating deadly conditions for firefighters operating on and under the roof. Structural collapse accounted for 180 firefighter deaths between 1979 and 2002 of which one-third occurred in residential structures . Many of these incidents involved a roof falling on firefighters or firefighters falling through the roof during firefighting operations on attic fires. The purpose of this study is to increase firefighter safety by providing the fire service with scientific knowledge on the dynamics of attic and exterior fires and the influence of coordinated fire mitigation tactics from full-scale fire testing in realistic residential structures.
5
Kerber, Steve, e Robin Zevotek. Study of Residential Attic Fire Mitigation Tactics and Exterior Fire Spread Hazards on Firefighter Safety Released. UL Firefighter Safety Research Institute, novembre 2014. http://dx.doi.org/10.54206/102376/lihb1439.
Abstract (sommario):
Attic fires pose many hazards for the fire service. When a fire occurs in an attic, it is common it goes unnoticed/reported until smoke or flames are visible from the outside of the structure. Because they take longer to detect, attic fires are more dangerous for firefighters and residents. In a fire situation, the attic ventilation system, which is designed to reduce moisture accumulation by drawing fresh air low from the eaves and exhausting moisture laden warm air near the peak, create an optimal fire growth and spread situation by supplying oxygen to the fire and exhausting hot gases. An estimated 10,000 residential attic fires are reported to U.S. fire departments each year and cause an estimated 30 civilian deaths, 125 civilian injuries and $477 million in property loss. The location of the attic creates several difficulties for the fire service. Firefighters must decide whether to fight the fire from inside the structure, from the outside or a combination of the two. This the decision is complicated by the constant hazard of ceiling collapse, which has the potential to rapidly deteriorate conditions in the living spaces. A piece of gypsum board may fall or be pulled from the ceiling making the relatively clear and cool conditions in the living space change very quickly endangering firefighters executing a search and rescue operation as part of their life safety mission. Further complicating the decision are the hazards associated with roof structure collapse, creating deadly conditions for firefighters operating on and under the roof. Structural collapse accounted for 180 firefighter deaths between 1979 and 2002 of which one-third occurred in residential structures . Many of these incidents involved a roof falling on firefighters or firefighters falling through the roof during firefighting operations on attic fires. The purpose of this study is to increase firefighter safety by providing the fire service with scientific knowledge on the dynamics of attic and exterior fires and the influence of coordinated fire mitigation tactics from full-scale fire testing in realistic residential structures.