Littérature scientifique sur le sujet « Decision Procedures Hypergeometric Sequences »
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Articles de revues sur le sujet "Decision Procedures Hypergeometric Sequences"
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Wagner, Kyle, Alex Smith, Abigail Allen, Kristen McMaster, Apryl Poch et Erica Lembke. « Exploration of New Complexity Metrics for Curriculum-Based Measures of Writing ». Assessment for Effective Intervention 44, no 4 (28 mai 2018) : 256–66. http://dx.doi.org/10.1177/1534508418773448.
Texte intégralRésumé :
Researchers and practitioners have questioned whether scoring procedures used with curriculum-based measures of writing (CBM-W) capture growth in complexity of writing. We analyzed data from six independent samples to examine two potential scoring metrics for picture word CBM-W (PW), a sentence-level CBM task. Correct word sequences per response (CWSR) and words written per response (WWR) were compared with the current standard metric of correct word sequences (CWS). Linear regression analyses indicated that CWSR predicted scores on standardized norm-referenced criterion measures in more samples than did WWR or CWS. Future studies should explore the capacity of CWSR and WWR to show growth over time, stability, diagnostic accuracy, and utility for instructional decision making.
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Strough, JoNell, Wändi Bruine de Bruin et Andrew M. Parker. « Taking the Biggest First : Age Differences in Preferences for Monetary and Hedonic Sequences ». Journals of Gerontology : Series B 74, no 6 (4 janvier 2018) : 964–74. http://dx.doi.org/10.1093/geronb/gbx160.
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Abstract Objectives People face decisions about how to sequence payments and events, including when to schedule bigger events relative to smaller ones. We examine age differences in these sequence preferences. Methods We gave a national adult life-span sample (n = 1,296, mean = 53.06 years, standard deviation = 16.33) four scenarios describing a positive or negative hedonic (enjoyable weekends, painful dental procedures) or monetary (receiving versus paying money) event. We considered associations among age, sequence preferences, three self-reported decision-making processes—emphasizing experience, emotion, and reasoning—and two dimensions of future time perspective—focusing on future opportunities and limited time. Results Older age was associated with taking the “biggest” event sooner instead of later, especially for receiving money, but also for the other three scenarios. Older age was associated with greater reported use of reason and experience and lesser reported use of emotion. These decision-making processes played a role in understanding age differences in sequence preferences, but future time perspective did not. Discussion We discuss “taking the biggest first” preferences in light of prior mixed findings on age differences in sequence preferences. We highlight the distinct roles of experience- and emotion-based decision-making processes. We propose applications to financial and health-care settings.
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Xu, Zhou Bo, Tian Long Gu, Liang Chang et Feng Ying Li. « A Novel Symbolic OBDD Algorithm for Generating Mechanical Assembly Sequences Using Decomposition Approach ». Advanced Materials Research 201-203 (février 2011) : 24–29. http://dx.doi.org/10.4028/www.scientific.net/amr.201-203.24.
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The compact storage and efficient evaluation of feasible assembly sequences is one crucial concern for assembly sequence planning. The implicitly symbolic ordered binary decision diagram (OBDD) representation and manipulation technique has been a promising way. In this paper, Sharafat’s recursive contraction algorithm and cut-set decomposition method are symbolically implemented, and a novel symbolic algorithm for generating mechanical assembly sequences is presented using OBDD formulations of liaison graph and translation function. The algorithm has the following main procedures: choosing any one of vertices in the liaison graph G as seed vertex and scanning all connected subgraphs containing seed vertex by breadth first search; transforming the problem of enumerating all cut-sets in liaison graph into the problem of generating all the partitions: two subsets V1and V2of a set of vertices V where both the induced graph of vertices V1and V2are connected; checking the geometrical feasibility for each cut-set. Some applicable experiments show that the novel algorithm can generate feasible assembly sequences correctly and completely.
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Khan, M. Shamim, Alex Chong et Tom Gedeon. « A Methodology for Developing Adaptive Fuzzy Cognitive Maps for Decision Support ». Journal of Advanced Computational Intelligence and Intelligent Informatics 4, no 6 (20 novembre 2000) : 403–7. http://dx.doi.org/10.20965/jaciii.2000.p0403.
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Differential Hebbian Learning (DHL) was proposed by Kosko as an unsupervised learning scheme for Fuzzy Cognitive Maps (FCMs). DHL can be used with a sequence of state vectors to adapt the causal link strengths of an FCM. However, it does not guarantee learning of the sequence by the FCM and no concrete procedures for the use of DHL has been developed. In this paper a formal methodology is proposed for using DHL in the development of FCMs in a decision support context. The four steps in the methodology are: (1) Creation of a crisp cognitive map; (2) Identification of event sequences for use in DHL; (3) Event sequence encoding using DHL; (4) Revision of the trained FCM. Feasibility of the proposed methodology is demonstrated with an example involving a dynamic system with feedback based on a real-life scenario.
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Orakçı, Erhan, et Ali Özdemir. « Using Social Choice Function for Multi Criteria Decision Making Problems ». Alphanumeric Journal 12, no 1 (20 juillet 2024) : 21–38. http://dx.doi.org/10.17093/alphanumeric.1426694.
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Many social choice preference functions or aggregation techniques, such as Borda, Copeland, Dodgson, Kemeny, are employed to obtain integrated solutions in multi-criteria decision problems. On the other hand, the number of studies comparing these techniques in the context of aggregation procedures in multi-criteria decision problems is limited. Furthermore, the advantages and disadvantages of the techniques have not been adequately discussed. In this context, the applicability of Borda, Copeland Dodgson, and Kemeny techniques in solving multi-criteria decision problems was investigated in this study. Analyses were performed on 500,000 samples containing various alternatives and sequences produced using the R software. The Kendall W test was used to assess the compatibility of the aggregation techniques. As a result, as the number of alternatives in the problem increases, the examined techniques produce an incomplete ranking. The features of the new aggregation technique to be developed were also determined in the context of the obtained results.
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Marchand, Pascal, et Claude Navarro. « Dialog Organization and Functional Communication in a Medical Assistance Task by Phone ». Perceptual and Motor Skills 81, no 2 (octobre 1995) : 451–61. http://dx.doi.org/10.1177/003151259508100218.
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This study is based on a corpus of 110 dialogs recorded in a medical assistance telephonist's workstation. Given the nature of the task, we have considered five main variables in dialog (topics) as well as their order of occurrence (sequences). These data were analyzed with a lexical analysis program. Results show a great difference between Operator/Specialist dialog and Operator/Nonspecialist dialog. Dialog “script” is very strong in the first case in which the operator merely plays a feedback role (routine procedures). If the caller is a private individual, the situation is often an indefinite problem, and the operator may have to adapt to the person (weak script) to obtain relevant information as quickly as possible (problem-solving procedures). This provides confirmation of the operator's twofold competence (efficient decision-making, dialog management).
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Bibilo, P. N., Yu Yu Lankevich et V. I. Romanov. « Logical Minimization of Multilevel Representations of Boolean Function Systems ». Informacionnye Tehnologii 29, no 2 (20 février 2023) : 59–71. http://dx.doi.org/10.17587/it.29.59-71.
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A decisive influence on complexity and speed of a combinational logic circuit of library CMOS elements is exerted by the preliminary stage of technologically independent optimization of the implemented system of Boolean functions. At present, the main methods of such optimization in the logical synthesis of custom CMOS VLSI blocks are methods for minimizing binary decision diagrams — Binary Decision Diagrams (BDD) or their modifications. Graphical representations of BDD are built on the basis of the Shannon expansions of Boolean functions. A BDD graph corresponds to a set of interrelated Shannon expansion formulas that form a multilevel representation of the minimized system of Boolean functions. The efficiency of applying various optimization procedures of minimization for several types of BDD representations of systems of Boolean functions is investigated in the paper. 7hese procedures are used as a technologically independent optimization in the synthesis of multi-output logic circuits of library CMOS elements. In addition to single logical optimization procedures, sequences of such procedures are studied that form various methods of logical optimization of multilevel representations of systems of Boolean functions. The results of experiments on 49 examples of systems of Boolean functions are presented. 25 optimization routes have been studied, efficient routes have been determined for various types of specifications of function systems. The obtained experimental results are compared with the known ones. It has been established that to estimate the complexity of optimized algebraic representations of systems of functions, it is advisable to use such a criterion as the total number of literals (variables or their inversions) of Boolean variables.
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Pathiraja Rathnayaka Hitige, Nadeesha, Ting Song, Steven J. Craig, Kimberley J. Davis, Xubing Hao, Licong Cui et Ping Yu. « An Ontology-Based Approach for Understanding Appendicectomy Processes and Associated Resources ». Healthcare 13, no 1 (24 décembre 2024) : 10. https://doi.org/10.3390/healthcare13010010.
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Background: Traditional methods for analysing surgical processes often fall short in capturing the intricate interconnectedness between clinical procedures, their execution sequences, and associated resources such as hospital infrastructure, staff, and protocols. Aim: This study addresses this gap by developing an ontology for appendicectomy, a computational model that comprehensively represents appendicectomy processes and their resource dependencies to support informed decision making and optimise appendicectomy healthcare delivery. Methods: The ontology was developed using the NeON methodology, drawing knowledge from existing ontologies, scholarly literature, and de-identified patient data from local hospitals. Results: The resulting ontology comprises 108 classes, including 11 top-level classes and 96 subclasses organised across five hierarchical levels. The 11 top-level classes include “clinical procedure”, “appendicectomy-related organisational protocols”, “disease”, “start time”, “end time”, “duration”, “appendicectomy outcomes”, “hospital infrastructure”, “hospital staff”, “patient”, and “patient demographics”. Additionally, the ontology includes 77 object and data properties to define relationships and attributes. The ontology offers a semantic, computable framework for encoding appendicectomy-specific clinical procedures and their associated resources. Conclusion: By systematically representing this knowledge, this study establishes a foundation for enhancing clinical decision making, improving data integration, and ultimately advancing patient care. Future research can leverage this ontology to optimise healthcare workflows and outcomes in appendicectomy management.
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Petrosyan, Azniv F. « Importance Rearrangement within Education, Economy and Natural Protection Ministries for Armenian Composite Supportive Progress (ACASP) ». Business and Management Studies 2, no 3 (23 août 2016) : 78. http://dx.doi.org/10.11114/bms.v2i3.1834.
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Sustainable Development is an innovative concept characterized as Composite Appraising Supportive Progress of Armenia (ACASP). Biodiversity concept is another topic having a vast power on public management and employment. Social, economic and environmental impacts optimize sequences within Education (S3), Economy (E5), Air (N3) & Land (N1) Ministries. Seven (7) phases of Operation Research (OR) studies correspond to nine (9) procedures of composite progressive indicators. Two (2) techniques are applied as decision making of utility function and transportation tasks. North-West Corner Rule (NWCR) and Low Cost Cell Rule (LCCR) are applied to manage public employment as per Education (S3), Economy (E5), Land (N1) and Air (N3) magnitudes of ACASP. A motivating approach is pertained not only to pick the order of significance as per biodiversity concept, but also to characterize the process of decision making through operation research techniques, particularly transportation assignments as per origins and destinations with supply and demand applications. The resulting sequence is revealed by sustenance of biodiversity concept with public employment of Armenian CASP.
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Reichelt, Florian, Dietmar Traub et Thomas Maier. « DERIVATION OF A METHOD DNA FOR THE UNIFIED DESCRIPTION OF METHODICAL PROCEDURES IN PRODUCT DEVELOPMENT ». Proceedings of the Design Society 3 (19 juin 2023) : 1187–96. http://dx.doi.org/10.1017/pds.2023.119.
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AbstractThe number of publications on methods in product development is increasing constantly. In addition to scientific models, method guidelines exist in practice to support the selection of suitable methods. When looking more closely, it is noticeable that new methods are not new developments of methodical principles, but rather adaptations and summaries of known methods to specific application areas.Although approaches to standardize methods exist, they are usually formulated too abstractly to be useful to project managers as a support for method decision making.In our contribution, we analyse common methods of technical product development regarding similarities in content and time. In doing so, we were able to derive a method DNA on the basis of which all methods can be described and, above all, distinguished in a verifiable manner. In addition to essential activity blocks, the DNA also includes the description of temporal sequences, which in particular enables a differentiation between agile and classic methods. Ultimately, the method DNA not only offers the chance to make methodical work comprehensible, but also the possibility to select methods specifically for upcoming development steps arises through the classification option.
Thèses sur le sujet "Decision Procedures Hypergeometric Sequences"
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Nosan, Klara. « Zero problems in polynomial models ». Electronic Thesis or Diss., Université Paris Cité, 2024. http://www.theses.fr/2024UNIP7008.
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Les modèles polynomiaux sont omniprésents en informatique, dans l'étude des automates et des langages formels, de l'optimisation, de la théorie des jeux, de la théorie du contrôle et de nombreux autres domaines. Dans cette thèse, nous considérons des modèles décrits par des systèmes d'équations polynomiales et des équations différentielles, où le système évolue à travers un ensemble discret de pas de temps avec des mises à jour polynomiales à chaque pas. Nous explorons trois aspects des « problèmes de zéros » pour les modèles polynomiaux : le test d'identité pour les expressions algébriques données par des polynômes, la détermination de l'existence de racines pour les systèmes polynomiaux et la détermination de l'existence de zéros dans les suites satisfaisant des récurrences à coefficients polynomiaux. Dans la première partie, nous étudions les tests d'identité pour les expressions algébriques impliquant des radicaux. En d'autres termes, étant donné un polynôme à k variables représenté par un circuit algébrique et k radicaux réels, nous examinons la complexité de déterminer si le polynôme s'annule sur l'entrée. Nous améliorons la borne PSPACE existante, en plaçant le problème dans coNP en supposant l'hypothèse de Riemann généralisée (HRG). Nous considérons ensuite une version restreinte du problème, où les entrées sont des racines carrées de nombres premiers impairs, montrant qu'il peut être résolu en temps polynomial randomisé en supposant HRG. Nous considérons ensuite les systèmes d'équations polynomiales et étudions la complexité de déterminer si un système de polynômes à coefficients polynomials a une solution. Nous présentons une approche du problème basée sur la théorie des nombres, généralisant les techniques utilisées pour les tests d'identité, et montrons que le problème appartient à la classe de complexité AM en supposant HRG. Nous analysons le lien entre ce problème et le problème de la détermination de la dimension d'une variété complexe, dont l'appartenance à AM a déjà été prouvé supposant HRG. Dans la dernière partie de cette thèse, nous analysons les suites satisfaisant des récurrences à coefficients polynomiaux. Nous étudions la question de savoir si zéro appartient d'une suite récursive polynomiale résultant d'une somme de deux suites hypergéométriques. Plus précisément, nous considérons le problème pour les suites dont les coefficients polynomiaux se décomposent dans le corps des rationnels Q. Nous montrons sa relation avec les valeurs de la fonction Gamma évaluées en des points rationnels, ce qui permet d'établir la décidabilité du problème supposant la conjecture de Rohrlich-Lang. Nous proposons une nouvelle approche basée sur l'étude des diviseurs premiers de la suite, ce qui nous permet d'établir la décidabilité inconditionnelle du problèmePolynomial models are ubiquitous in computer science, arising in the study of automata and formal languages, optimisation, game theory, control theory, and numerous other areas. In this thesis, we consider models described by polynomial systems of equations and difference equations, where the system evolves through a set of discrete time steps with polynomial updates at every step. We explore three aspects of "zero problems" for polynomial models: zero testing for algebraic expressions given by polynomials, determining the existence of zeros for polynomial systems and determining the existence of zeros for sequences satisfying recurrences with polynomial coefficients. In the first part, we study identity testing for algebraic expressions involving radicals. That is, given a k-variate polynomial represented by an algebraic circuit and k real radicals, we examine the complexity of determining whether the polynomial vanishes on the radical input. We improve on the existing PSPACE bound, placing the problem in coNP assuming the Generalised Riemann Hypothesis (GRH). We further consider a restricted version of the problem, where the inputs are square roots of odd primes, showing that it can be decided in randomised polynomial time assuming GRH. We next consider systems of polynomial equations, and study the complexity of determining whether a system of polynomials with polynomial coefficients has a solution. We present a number-theoretic approach to the problem, generalising techniques used for identity testing, showing the problem belongs to the complexity class AM assuming GRH. We discuss how the problem relates to determining the dimension of a complex variety, which is also known to belong to AM assuming GRH. In the final part of this thesis, we turn our attention to sequences satisfying recurrences with polynomial coefficients. We study the question of whether zero is a member of a polynomially recursive sequence arising as a sum of two hypergeometric sequences. More specifically, we consider the problem for sequences where the polynomial coefficients split over the field of rationals Q. We show its relation to the values of the Gamma function evaluated at rational points, which allows to establish decidability of the problem under the assumption of the Rohrlich-Lang conjecture. We propose a different approach to the problem based on studying the prime divisors of the sequence, allowing us to establish unconditional decidability of the problem
Chapitres de livres sur le sujet "Decision Procedures Hypergeometric Sequences"
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Jeż, Artur, Anthony W. Lin, Oliver Markgraf et Philipp Rümmer. « Decision Procedures for Sequence Theories ». Dans Computer Aided Verification, 18–40. Cham : Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-37703-7_2.
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AbstractSequence theories are an extension of theories of strings with an infinite alphabet of letters, together with a corresponding alphabet theory (e.g. linear integer arithmetic). Sequences are natural abstractions of extendable arrays, which permit a wealth of operations including append, map, split, and concatenation. In spite of the growing amount of tool support for theories of sequences by leading SMT-solvers, little is known about the decidability of sequence theories, which is in stark contrast to the state of the theories of strings. We show that the decidable theory of strings with concatenation and regular constraints can be extended to the world of sequences over an alphabet theory that forms a Boolean algebra, while preserving decidability. In particular, decidability holds when regular constraints are interpreted as parametric automata (which extend both symbolic automata and variable automata), but fails when interpreted as register automata (even over the alphabet theory of equality). When length constraints are added, the problem is Turing-equivalent to word equations with length (and regular) constraints. Similar investigations are conducted in the presence of symbolic transducers, which naturally model sequence functions like map, split, filter, etc. We have developed a new sequence solver, SeCo, based on parametric automata, and show its efficacy on two classes of benchmarks: (i) invariant checking on array-manipulating programs and parameterized systems, and (ii) benchmarks on symbolic register automata.
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Cauli, Claudia, Magdalena Ortiz et Nir Piterman. « Actions over Core-Closed Knowledge Bases ». Dans Automated Reasoning, 281–99. Cham : Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-10769-6_17.
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AbstractWe present new results on the application of semantic- and knowledge-based reasoning techniques to the analysis of cloud deployments. In particular, to the security of Infrastructure as Code configuration files, encoded as description logic knowledge bases. We introduce an action language to model mutating actions; that is, actions that change the structural configuration of a given deployment by adding, modifying, or deleting resources. We mainly focus on two problems: the problem of determining whether the execution of an action, no matter the parameters passed to it, will not cause the violation of some security requirement (static verification), and the problem of finding sequences of actions that would lead the deployment to a state where (un)desirable properties are (not) satisfied (plan existence and plan synthesis). For all these problems, we provide definitions, complexity results, and decision procedures.
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Hai-Jew, Shalin. « Optimizing Static and Dynamic Visual Expressions of Time-Based Events, Processes, Procedures, and Future Projections for Instructional Design ». Dans Form, Function, and Style in Instructional Design, 134–50. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-5225-9833-6.ch007.
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Time-based visuals are used to depict time-based events, processes, procedures, and future projections, among others. These come in 2D, 3D, and 4D types, and they may be static or dynamic, non-interactive, or interactive. A simple process or procedure may be expressed visually as a timeline, a flowchart, a stacked diagram, a node-link game tree, a workflow diagram, dedicated-type sequence diagrams, or some other sequence-based visual. With the proliferation of more complex time-based sequences—with multiple paths, multiple actors, decision junctures, conditionals, and other forms of dimensionality, and with multimodal expressions and interactive digital interfaces, with processes as descriptions, theorized steps, directional procedures, projections, and other types—the visual depictions of processes and procedures have become much more complex and layered. This work describes some efforts to optimize these visual expressions through proper design, development, testing, and revision.
Actes de conférences sur le sujet "Decision Procedures Hypergeometric Sequences"
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Clauss, Gu¨nther F., Sascha Kosleck et Daniel Testa. « Critical Situations of Vessel Operations in Short Crested Seas : Forecast and Decision Support System ». Dans ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79482.
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The encounter of extreme waves, extreme wave groups or of unfavourable wave sequences is a dangerous thread for ships and floating/fixed marine structures. The impact of extreme waves causes enormous forces whereas the encounter of an unfavourable wave sequence — not necessarily extreme waves — can arouse critical motions or even resonance, often leading to loss of cargo, ship and crew. Thus, besides a well thought-out maritime design, a system detecting critical incoming wave sequences in advance can help avoiding those dangerous situations, increasing the safety of sea transport or offshore operations. During the last two years (see [1] and [2]) a new system for decision support on board a ship or floating/fixed marine structure named CASH — Computer Aided Ship Handling — has been introduced. The preceding papers showed the step wise development of the main components of the program code — 3D–WAVE FORECAST and 3D–SHIP MOTION FORECAST. These procedures provide a deterministic approach to predict the short-crested seas state within radar range of the ship, as well as resulting ship motions in 6 degrees of freedom. Both methods have been enhanced with special focus on the speed of calculation to ensure a just-in-time forecast. A newly developed component is the ADAPTIVE 3D-PRESSURE DISTRIBUTION. This method calculates the pressure distribution along the wetted surface of the ship hull using a newly developed stretching approach [3]. With the end of the joint project LaSSe — Loads on Ships in Seaway (funded by the German Government) the paper presents the CASH-system, giving the possibility to detect critical situations in advance. Thus not only decision support on board a cruising ship can be provided, but also time windows for offshore operations are identified well in advance.
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Antani, Kavit R., Bryan Pearce, Laine Mears, Rahul Renu, Mary E. Kurz et Joerg Schulte. « Application of System Learning to Precedence Graph Generation for Assembly Line Balancing ». Dans ASME 2014 International Manufacturing Science and Engineering Conference collocated with the JSME 2014 International Conference on Materials and Processing and the 42nd North American Manufacturing Research Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/msec2014-3906.
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Manufacturing Process Planning is the systematic development of the detailed methods by which products can be manufactured in a cost-efficient manner, while achieving their functional requirements. An assembly line is a flow-oriented production system where the productive units performing the operations, referred to as stations, are aligned in a serial manner. The work pieces visit stations successively as they are moved along the line usually by some kind of transportation system, e.g., a conveyor belt. An important decision problem, called Assembly Line Balancing Problem (ALBP), arises and has to be solved when (re-) configuring an assembly line. It consists of distributing the work tasks among the work stations along the line due to changes in task requirements for planned production. The assignment of tasks to stations is constrained by task sequence restrictions which can be expressed in a precedence graph. However, most manufacturers usually do not have precedence graphs or if they do, the information on their precedence graphs is inadequate. As a consequence, the elaborate solution procedures for different versions of ALBP developed by more than 50 years of research are often not applicable in practice as not all constraint information is known. This is a common problem in automotive final assembly. In this work we describe a novel precedence generation technique that is based on system-learning from past feasible production sequences. This technique forms a sufficient precedence graph that guarantees feasible line balances. Experiments indicate that the proposed procedure is able to approximate a precedence graph generated by an expert sufficiently well to detect nearly-optimal solutions even for a real-world automotive assembly line segment. Thus, the application of system learning seems to provide a simple and practical way to implement Decision Support Systems to make assembly line planning more efficient.
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Al Kalbani, H. « Lessons from a Year-Long Operation of an Atmospheric Pressure Flare Gas Recovery System ». Dans SPE Conference at Oman Petroleum & Energy Show. SPE, 2024. http://dx.doi.org/10.2118/218652-ms.
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Abstract As the world approaches the 2030 deadline set by the World Bank to eliminate routine flaring, substantial investments are directed towards establishing flare gas recovery, treatment and export infrastructure. This paper delves into the critical components of this imperative task: isolating the flare system and implementing a gas recovery system. The objective is to distill valuable insights and lessons learned from our year-long experience operating such a system, providing a valuable resource for future projects. The lessons learned encompass concept development, design considerations, commissioning procedures, and essential operational aspects. These lessons cover a broad spectrum of critical considerations, including compressor selection, process design fundamentals, control, startup & shutdown sequences, commissioning procedures and underscore the paramount importance of comprehensive training protocols. The flare gas recovery project aimed to capture gas from atmospheric pressure (AP) sources within the plant. The AP flare gas network intricately collects atmospheric gas from diverse sources, including free water knockout tanks, skim tanks, buffer tanks, drain vessels, skimming vessels, purge gas, and more. The project installed an efficient isolation system which directs this gas to the newly installed gas recovery compressor, where the gas is compressed before being sent for further treatment. Compressor selection was a crucial decision, and the project ultimately chose the rotary vane compressor due to its exceptional robustness in handling wet gas. Determining the compressor's flowrate entailed a meticulous process, factoring in operational dynamics, site-specific conditions, and gas flashing considerations. Implementing the control schematic was equally careful, given the challenge of low suction pressure. Careful placement of pressure transducers ensured adequate volume at compressor suction to prevent pressure spikes triggering frequent shutdowns. The isolation system incorporated both an emergency shutdown valve and a pressure control valve, designed to re-route gas back to the flare when necessary The start-up sequence was thoughtfully designed to meet the dual requirements of isolating the flare while preventing back pressure in the connected tank until the compressor was in operation. Similarly, the shutdown sequence was carefully engineered to prevent the compressor from running while the flare emergency shutdown valve was open. Rigorous commissioning involved using fuel gas to validate the control scheme's functionality, ensuring it operated as intended. Training considerations were integral from the project's inception, incorporated into design reviews and Hazard and Operability Studies (HAZOPs) and upheld during commissioning. In summary, our experience underscores the indispensable role of meticulous planning, technology selection, and comprehensive training in realizing efficient and environmentally responsible gas recovery project.
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Antani, Kavit R., Bryan Pearce, Mary E. Kurz, Laine Mears, Kilian Funk et Maria E. Mayorga. « Manual Precedence Mapping and Application of a Novel Precedence Relationship Learning Technique to Real-World Automotive Assembly Line Balancing ». Dans ASME 2013 International Manufacturing Science and Engineering Conference collocated with the 41st North American Manufacturing Research Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/msec2013-1235.
Texte intégralRésumé :
An assembly line is a flow-oriented production system where the productive units performing the operations, referred to as stations, are aligned in a serial manner. The work pieces visit stations successively as they are moved along the line usually by some kind of transportation system, e.g., a conveyor belt. An important decision problem, called Assembly Line Balancing Problem (ALBP), arises and has to be solved when (re-) configuring an assembly line. It consists of distributing the total workload for manufacturing any unit of the product to be assembled among the work stations along the line. The assignment of tasks to stations is constrained by task sequence restrictions which can be expressed in a precedence graph. However, most manufacturers usually do not have precedence graphs or if they do, the information on their precedence graphs is inadequate. As a consequence, the elaborate solution procedures for different versions of ALBP developed by more than 50 years of intensive research are often not applicable in practice. Unfortunately, the known approaches for precedence graph generation are not suitable for the conditions in the automotive industry. Therefore, we describe a detailed application of a new graph generation approach first introduced by Klindworth et al. [1] that is based on learning from past feasible production sequences. This technique forms a sufficient precedence graph that guarantees feasible line balances. Experiments indicate that the proposed procedure is able to approximate the real precedence graph sufficiently well to detect nearly optimal solutions even for a real-world automotive assembly line segment with up to 317 tasks. In particular, it seems to be promising to use interviews with experts in a selective manner by analyzing maximum and minimum graphs to identify still assumed relations that are crucial for the graph’s structure. Thus, the new approach seems to be a major step to close the gap between theoretical line balancing research and practice of assembly line planning.
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Schneider, Raymond E., et Steven E. Farkas. « Transition Risk Method and Example ». Dans 12th International Conference on Nuclear Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/icone12-49519.
Texte intégralRésumé :
Paragraph (a)(4) of the Maintenance Rule (re 10CFR§50.65) states that before performing maintenance activities, the licensees shall assess and manage the increase in risk that may result from the maintenance activities. The rule is explicitly applicable to all operating modes. Currently, most plants use a qualitative tool for assessing and controlling the risk of the various plant conditions during an outage. Fewer plants have any means of performing a quantitative or qualitative assessment of the associated risks of transitioning the plant in each configuration from power to “cold shutdown.” Typically, only the end-state of shutdown is considered. The transition-period includes short-duration configurations when the available set of equipment is not what it was during power operations, e.g., having only one main feedwater train in-service. Given the concern that the NRC may require quantitative risk assessments of plant transitions and plant configurations during shutdown operations, Omaha Public Power District (OPPD) pro-actively authorized Westinghouse Engineering Services to develop a method for assessing risk associated with a transition from all power to shutdown and back to full power. An outage schedule is highly plant specific, with plant-to-plant and outage-to-outage variations in system configurations, and maintenance practices. Accordingly, the duration of the transition largely depends on equipment maintenance activities driving the decision to shutdown and repair. The time spent in various parts of the transition is a strong determinant in the associated risk of the transition. A transition takes the plant through a series of Plant Operational States (POSs). The features important to the characterization of each of the POSs include decay-heat level, plant activities involved, available equipment, as well as RCS temperature and pressure. The risk of the entire transition comes from calculating a figure-of-merit of each POS which can be loosely thought of as a per-hour core-damage frequency (CDF). This number gets multiplied by the associated duration of the POS. The sum is the transition risk. The effective CDF associated with the transition comes from dividing the POS-specific CDF sum by the total transition time, and converting that result to an annual frequency. Our paper describes decomposing OPPD operating procedures into periods for which we quantified sequences. In particular, the method considers the dominant shutdown failure modes: loss of shutdown cooling, loss of inventory, and loss of offsite power (including both plant centered and grid-related events). The transition example presented herein covers a simple shutdown and restart stemming from an indeterminate-quality problem. That is, all equipment is functional and available to the plant operators.
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Yessalina, S. A., R. A. Gulamov, S. E. Mallaev, A. S. Muratov, M. N. Muminov, A. M. Kuvanyshev, B. S. Khairaliyev et al. « Revealing New Exploration Plays in the Deeper Parts of the Ustyurt Region in Uzbekistan ». Dans GOTECH. SPE, 2024. http://dx.doi.org/10.2118/219312-ms.
Texte intégralRésumé :
Abstract Objectives/Scope The Berdakh-Sudochi region, the promising frontier exploration area of Uzbekistan have been studied for basin modeling to optimize exploration drilling campaign. The objective of this study was to assess the overall potential of deeper poorly explored Lower Jurassic sequences, based on analyses of field data, regional geological framework and petroleum system. Methods, Procedures, Process An integrated approach has been applied for petroleum system modeling of the Jurassic sediments in the study area. The basin models have been built based on comprehensive review of all collected regional geological, geophysical, and field data. Interpreted seismic data have been utilized to build the subsurface structural framework of the basin. Distribution of depositional facies have been constrained based on analyses of well logs, seismic attributes, core data and existing regional studies. This basic geological concept served as the main input for assessment of petroleum system elements and reconstruction of burial and thermal histories. Results, Observations, Conclusions The Jurassic formations in the study area were controlled by the development of the Sudochi paleorift active till Lower Jurassic. Active rifting had dramatic effects on hydrocarbon system. The paleorift provided an effective kitchen for organic maturation in the deeper subsided part of the region. Rapid sedimentation led to deposition of thick basal reservoir rocks at the margins of the basin. The results of regional geological studies and petroleum system modeling showed promising potential for the Lower Jurassic sediments underlying the producing intervals. Reconstructed burial and thermal histories favor the Lower Jurassic in terms of hydrocarbon generation and timing of expulsion. High subsidence rates created favorable conditions for preservation and maturation of distal Lower Jurassic organic-rich sediments, with gas window starting at depth range of 3-4 km. The proximal Lower Jurassic fan deposits represent the best reservoir in terms of net thickness and continuity, overlain by fining upward fluvial sediments of Middle and Upper Jurassic. Close vicinity between kitchen and reservoir rocks facilitated effective migration and charge of traps. Recommended deepening of the existing wells till depth of 4500 m targeting Lower Jurassic fans has proved high potential of the sequence with commercial flow rates up to 1 MMscm/d. The new deep wells were planned at different parts of the paleo-rift to develop the new play. After drilling success followed by increase in production drilling an appraisal well down to 6500m was proposed and approved to explore the deeper syn-rift deposits and traps. Novel/Additive Information This work represents multidisciplinary study integrating regional geological and geophysical data. highlighting importance of petroleum system studies in reducing exploration risks by defining most promising targets for drilling. The results of this work opened new opportunities and had crucial impact on governmental decision to boost exploration activity in the Ustyurt region.