Bibliografías temáticas / Unit multiple interval graphs

Índice

Artículos de revistas
Tesis
Libros
Capítulos de libros
Actas de conferencias

Literatura académica sobre el tema "Unit multiple interval graphs"

Autor: Grafiati

Publicado: 21 de diciembre de 2024

Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros

Elija tipo de fuente:

Consulte las listas temáticas de artículos, libros, tesis, actas de conferencias y otras fuentes académicas sobre el tema "Unit multiple interval graphs".

Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.

También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.

Artículos de revistas sobre el tema "Unit multiple interval graphs"

Ardévol Martínez, Virginia, Romeo Rizzi, Florian Sikora y Stéphane Vialette. "Recognizing unit multiple interval graphs is hard". Discrete Applied Mathematics 360 (enero de 2025): 258–74. http://dx.doi.org/10.1016/j.dam.2024.09.011.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Cardoza, Jacqueline E., Carina J. Gronlund, Justin Schott, Todd Ziegler, Brian Stone y Marie S. O’Neill. "Heat-Related Illness Is Associated with Lack of Air Conditioning and Pre-Existing Health Problems in Detroit, Michigan, USA: A Community-Based Participatory Co-Analysis of Survey Data". International Journal of Environmental Research and Public Health 17, n.º 16 (7 de agosto de 2020): 5704. http://dx.doi.org/10.3390/ijerph17165704.

Texto completo

Resumen

The objective of the study was to investigate, using academic-community epidemiologic co-analysis, the odds of reported heat-related illness for people with (1) central air conditioning (AC) or window unit AC versus no AC, and (2) fair/poor vs. good/excellent reported health. From 2016 to 2017, 101 Detroit residents were surveyed once regarding extreme heat, housing and neighborhood features, and heat-related illness in the prior 5 years. Academic partners selected initial confounders and, after instruction on directed acyclic graphs, community partners proposed alternate directed acyclic graphs with additional confounders. Heat-related illness was regressed on AC type or health and co-selected confounders. The study found that heat-related illness was associated with no-AC (n = 96, odds ratio (OR) = 4.66, 95% confidence interval (CI) = 1.22, 17.72); living ≤5 years in present home (n = 57, OR = 10.39, 95% CI = 1.13, 95.88); and fair/poor vs. good/excellent health (n = 97, OR = 3.15, 95% CI = 1.33, 7.48). Co-analysis suggested multiple built-environment confounders. We conclude that Detroit residents with poorer health and no AC are at greater risk during extreme heat. Academic-community co-analysis using directed acyclic graphs enhances research on community-specific social and health vulnerabilities by identifying key confounders and future research directions for rigorous and impactful research.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Rautenbach, Dieter y Jayme L. Szwarcfiter. "Unit Interval Graphs". Electronic Notes in Discrete Mathematics 38 (diciembre de 2011): 737–42. http://dx.doi.org/10.1016/j.endm.2011.10.023.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Dourado, Mitre C., Van Bang Le, Fábio Protti, Dieter Rautenbach y Jayme L. Szwarcfiter. "Mixed unit interval graphs". Discrete Mathematics 312, n.º 22 (noviembre de 2012): 3357–63. http://dx.doi.org/10.1016/j.disc.2012.07.037.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Grippo, Luciano N. "Characterizing interval graphs which are probe unit interval graphs". Discrete Applied Mathematics 262 (junio de 2019): 83–95. http://dx.doi.org/10.1016/j.dam.2019.02.022.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Kulik, Anatoliy, Sergey Pasichnik y Dmytro Sokol. "MODELING OF PHYSICAL PROCESSES OF ENERGY CONVERSION IN SMALL-SIZED VORTEX ENERGY SEPARATORS". Aerospace technic and technology, n.º 1 (26 de febrero de 2021): 20–30. http://dx.doi.org/10.32620/aktt.2021.1.03.

Texto completo

Resumen

The object of study in the article is the vortex effect of temperature separation in a rotating gas flow, which is realized in small-sized vortex energy separators. The subject matter is the models that describe the physical processes of energy conversion in small-sized vortex energy separators as objects of automatic control. The goal is to obtain models of a vortex energy separator reflecting its static and dynamic properties as an automatic control object. The tasks to be solved are: to develop a three-dimensional computer model of a small-sized vortex energy separator which will allow analyzing the parameters of the gas flow and physical processes of energy conversion directly inside the object and obtaining its static characteristics. A linearization method of static characteristics on the interval of input and output values is proposed which will expand the operating range without loss of linearization accuracy. A method of structural-parametric identification based on experimental logarithmic magnitude-frequency characteristics is proposed which will allow for the same set of experimental points to select the structure of the mathematical model of varying complexity depending on the specified accuracy. As a result of the work, the scheme for modeling the automatic control object was formed, consisting of the drive unit, sensor unit, and vortex energy separator, with the reflection of all the obtained operating modes. The methods used are the method of graphic linearization, Laplace transform, structural-parametric identification. The following results were obtained: a computer and linearized mathematical model of the small-sized vortex energy separator as an automatic control object reflecting its properties in the time and frequency domains was obtained. A comparative analysis of the reactions of the model and the real object to the same input action was carried out. Conclusions. The scientific novelty of the results obtained is as follows: 1) multiple graphic linearizations of one static characteristic to use the full range of the operation mode of vortex energy separator, which distinguishes it from the known;2) mathematical model structural-parametric identification for vortex energy separator with the help of known points of the Bode magnitude plots by using the interpolation polynomial and its derivatives graphs.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Le, Van Bang y Dieter Rautenbach. "Integral mixed unit interval graphs". Discrete Applied Mathematics 161, n.º 7-8 (mayo de 2013): 1028–36. http://dx.doi.org/10.1016/j.dam.2012.09.013.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Jinjiang, Yuan y Zhou Sanming. "Optimal labelling of unit interval graphs". Applied Mathematics 10, n.º 3 (septiembre de 1995): 337–44. http://dx.doi.org/10.1007/bf02662875.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Marx, Dániel. "Precoloring extension on unit interval graphs". Discrete Applied Mathematics 154, n.º 6 (abril de 2006): 995–1002. http://dx.doi.org/10.1016/j.dam.2005.10.008.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Lin, Min Chih, Francisco J. Soulignac y Jayme L. Szwarcfiter. "Short Models for Unit Interval Graphs". Electronic Notes in Discrete Mathematics 35 (diciembre de 2009): 247–55. http://dx.doi.org/10.1016/j.endm.2009.11.041.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Más fuentes

Tesis sobre el tema "Unit multiple interval graphs"

Ardevol, martinez Virginia. "Structural and algorithmic aspects of (multiple) interval graphs". Electronic Thesis or Diss., Université Paris sciences et lettres, 2024. http://www.theses.fr/2024UPSLD028.

Texto completo

Resumen

Les graphes d’intervalles multiples sont une généralisation bien connue des graphes d’intervalles, où chaque sommet d’un graphe est représenté par un d-intervalle (l’union de d intervalles) pour un certain nombre naturel d > 1, et il existe une arête entre deux sommets si et seulement si leurs d-intervalles correspondants se croisent. En particulier, un graphe de d-intervalles est unitaire si tous les intervalles de la représentation ont une longueur unitaire. Dans cette thèse, nous étudions les graphes de d-intervalles unitaires d’un point de vue structurel et algorithmique. Dans la première partie, nous essayons de généraliser la caractérisation de Roberts des graphes d’intervalles unitaires, qui affirme qu’un graphe est un graphe d’intervalles unitaire si et seulement s’il est un graphe d’intervalles et ne contient pas le graphe biparti complet K1,3 comme sous-graphe induit. Ensuite, nous passons à l’étude de la complexité de la reconnaissance des graphes d’intervalles multiples unitaires. Nous prouvons que, étant donné un graphe G, il est NP-difficile de déterminer si G est un graphe de d-intervalles unitaires, et nous étendons ensuite ce résultat de difficulté à d’autres sous-classes de graphes de d-intervalles unitaires. Dans la dernière partie de ce manuscrit, nous nous concentrons sur le problème de PIG-completion, qui étant donné un graphe d’intervalles G, demande de trouver le nombre minimum d’arêtes à ajouter à G pour qu’il devienne un graphe d’intervalles unitaire. Nous obtenons un algorithme polynomial lorsque G contient un sommet adjacent à tous les autres sommets du graphe, et un algorithme XP paramétré par une propriété structurelle du graphe
Multiple interval graphs are a well-known generalization of interval graphs, where each vertex of a graph is represented by a d-interval (the union of d intervals) for some natural number d > 1, and there exists an edge between two vertices if and only if their corresponding d-intervals intersect. In particular, a d-interval graph is unit if all the intervals on the representation have unit length. In this thesis, we study unit d-interval graphs from a structural and an algorithmic perspective. In the first part, we tryto generalize Roberts characterization of unit interval graphs, which states that a graph is unit interval if and only if it is interval and it does not contain the complete bipartite graph K1,3 as an induced subgraph. Then, we move on to studythe complexity of recognizing unit multiple interval graphs. We prove that given a graph G it is NP-hard to determine whether G is a unit d-interval graph, and then extend this hardness result to other subclasses of unit d-interval graphs. Inthe last part of this manuscript, we focus on the PIG-completion problem, where given an interval graph G, we are asked to find the minimum number of edges that we need to add to G so that it becomes a proper interval graph. We obtain apolynomial algorithm when G contains a vertex that is adjacent to every other vertex of the graph, and an XP algorithm parameterized by a structural property of the graph

Los estilos APA, Harvard, Vancouver, ISO, etc.

Vestin, Albin y Gustav Strandberg. "Evaluation of Target Tracking Using Multiple Sensors and Non-Causal Algorithms". Thesis, Linköpings universitet, Reglerteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-160020.

Texto completo

Resumen

Today, the main research field for the automotive industry is to find solutions for active safety. In order to perceive the surrounding environment, tracking nearby traffic objects plays an important role. Validation of the tracking performance is often done in staged traffic scenarios, where additional sensors, mounted on the vehicles, are used to obtain their true positions and velocities. The difficulty of evaluating the tracking performance complicates its development. An alternative approach studied in this thesis, is to record sequences and use non-causal algorithms, such as smoothing, instead of filtering to estimate the true target states. With this method, validation data for online, causal, target tracking algorithms can be obtained for all traffic scenarios without the need of extra sensors. We investigate how non-causal algorithms affects the target tracking performance using multiple sensors and dynamic models of different complexity. This is done to evaluate real-time methods against estimates obtained from non-causal filtering. Two different measurement units, a monocular camera and a LIDAR sensor, and two dynamic models are evaluated and compared using both causal and non-causal methods. The system is tested in two single object scenarios where ground truth is available and in three multi object scenarios without ground truth. Results from the two single object scenarios shows that tracking using only a monocular camera performs poorly since it is unable to measure the distance to objects. Here, a complementary LIDAR sensor improves the tracking performance significantly. The dynamic models are shown to have a small impact on the tracking performance, while the non-causal application gives a distinct improvement when tracking objects at large distances. Since the sequence can be reversed, the non-causal estimates are propagated from more certain states when the target is closer to the ego vehicle. For multiple object tracking, we find that correct associations between measurements and tracks are crucial for improving the tracking performance with non-causal algorithms.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Tu, Yuan-Lung y 塗元龍. "A Study on Unit Interval Graphs". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/76002582966141739137.

Texto completo

Resumen

碩士
輔仁大學
數學系碩士班
101
The purpose of this thesis is to study some characterizations of unit interval graphs and an algorithm that are used to recognize whethere a given graph is a unit interval graph or not. The former is based on the book ”Introduction to graph theory” written by D. B. West; and the latter is based on the paper ”A simple 3-sweep LBFS algorithm for the recognition of unit interval graphs” by D. G. Corneil.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Williams, Aaron Michael. "Shift gray codes". Thesis, 2009. http://hdl.handle.net/1828/1966.

Texto completo

Resumen

Combinatorial objects can be represented by strings, such as 21534 for the permutation (1 2) (3 5 4), or 110100 for the binary tree corresponding to the balanced parentheses (()()). Given a string s = s1 s2 sn, the right-shift operation shift(s, i, j) replaces the substring si si+1..sj by si+1..sj si. In other words, si is right-shifted into position j by applying the permutation (j j−1 .. i) to the indices of s. Right-shifts include prefix-shifts (i = 1) and adjacent-transpositions (j = i+1). A fixed-content language is a set of strings that contain the same multiset of symbols. Given a fixed-content language, a shift Gray code is a list of its strings where consecutive strings differ by a shift. This thesis asks if shift Gray codes exist for a variety of combinatorial objects. This abstract question leads to a number of practical answers. The first prefix-shift Gray code for multiset permutations is discovered, and it provides the first algorithm for generating multiset permutations in O(1)-time while using O(1) additional variables. Applications of these results include more efficient exhaustive solutions to stacker-crane problems, which are natural NP-complete traveling salesman variants. This thesis also produces the fastest algorithm for generating balanced parentheses in an array, and the first minimal-change order for fixed-content necklaces and Lyndon words. These results are consequences of the following theorem: Every bubble language has a right-shift Gray code. Bubble languages are fixed-content languages that are closed under certain adjacent-transpositions. These languages generalize classic combinatorial objects: k-ary trees, ordered trees with fixed branching sequences, unit interval graphs, restricted Schr oder and Motzkin paths, linear-extensions of B-posets, and their unions, intersections, and quotients. Each Gray code is circular and is obtained from a new variation of lexicographic order known as cool-lex order. Gray codes using only shift(s, 1, n) and shift(s, 1, n−1) are also found for multiset permutations. A universal cycle that omits the last (redundant) symbol from each permutation is obtained by recording the first symbol of each permutation in this Gray code. As a special case, these shorthand universal cycles provide a new fixed-density analogue to de Bruijn cycles, and the first universal cycle for the "middle levels" (binary strings of length 2k + 1 with sum k or k + 1).

Los estilos APA, Harvard, Vancouver, ISO, etc.

Libros sobre el tema "Unit multiple interval graphs"

Wijdicks, Eelco F. M. y Sarah L. Clark. Neurocritical Care Pharmacotherapy. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190684747.001.0001.

Texto completo

Resumen

Drugs are used to treat, salvage, and protect the brain. This book provides information on how to prescribe and monitor the drugs most frequently used in the emergency department and the neurosciences critical care unit. Each drug is discussed in great detail to allow for its efficient use and to allow the recognition of drug-related problems. The book explains how these drugs work and what the body does with the drug in the acutely ill neurologic patient. It provides guidance on how these drugs are best administered and revisits how we can most effectively practice medication reconciliation. This manual has multiple useful concise tables and graphs summarizing over 150 drugs.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Capítulos de libros sobre el tema "Unit multiple interval graphs"

Le, Van Bang y Dieter Rautenbach. "Integral Mixed Unit Interval Graphs". En Lecture Notes in Computer Science, 495–506. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-32241-9_42.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Joos, Felix. "A Characterization of Mixed Unit Interval Graphs". En Graph-Theoretic Concepts in Computer Science, 324–35. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-12340-0_27.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Jiang, Minghui y Yong Zhang. "Parameterized Complexity in Multiple-Interval Graphs: Domination". En Parameterized and Exact Computation, 27–40. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-28050-4_3.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Talon, Alexandre y Jan Kratochvil. "Completion of the Mixed Unit Interval Graphs Hierarchy". En Lecture Notes in Computer Science, 284–96. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-17142-5_25.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Alam, M. J., S. G. Kobourov, S. Pupyrev y J. Toeniskoetter. "Weak Unit Disk and Interval Representation of Graphs". En Graph-Theoretic Concepts in Computer Science, 237–51. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-53174-7_17.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Cao, Yixin. "Recognizing (Unit) Interval Graphs by Zigzag Graph Searches". En Symposium on Simplicity in Algorithms (SOSA), 92–106. Philadelphia, PA: Society for Industrial and Applied Mathematics, 2021. http://dx.doi.org/10.1137/1.9781611976496.11.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Klavík, Pavel, Jan Kratochvíl, Yota Otachi, Ignaz Rutter, Toshiki Saitoh, Maria Saumell y Tomáš Vyskočil. "Extending Partial Representations of Proper and Unit Interval Graphs". En Algorithm Theory – SWAT 2014, 253–64. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-08404-6_22.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Jiang, Minghui y Yong Zhang. "Parameterized Complexity in Multiple-Interval Graphs: Partition, Separation, Irredundancy". En Lecture Notes in Computer Science, 62–73. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-22685-4_6.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Francis, Mathew C., Daniel Gonçalves y Pascal Ochem. "The Maximum Clique Problem in Multiple Interval Graphs (Extended Abstract)". En Graph-Theoretic Concepts in Computer Science, 57–68. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-34611-8_9.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Zhou, Yunhong. "Improved Multi-unit Auction Clearing Algorithms with Interval (Multiple-Choice) Knapsack Problems". En Algorithms and Computation, 494–506. Berlin, Heidelberg: Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/11940128_50.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Actas de conferencias sobre el tema "Unit multiple interval graphs"

Sampaio Jr., Moysés S., Fabiano S. Oliveira y Jayme L. Szwarcfiter. "Sobre Finura Própria de Grafos". En III Encontro de Teoria da Computação. Sociedade Brasileira de Computação - SBC, 2018. http://dx.doi.org/10.5753/etc.2018.3165.

Texto completo

Resumen

Both graph classes of k-thin and proper k-thin graphs have recently been introduced generalizing interval and unit interval graphs, respectively. The complexity of the recognition of k-thin and proper k-thin are open, even for fixed k 2. In this work, we introduce a subclass of the proper 2-thin graphs, called proper 2-thin of precedence. For this class, we present a characterization and an efficient recognition algorithm.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Eisenstat, David y Philip N. Klein. "Linear-time algorithms for max flow and multiple-source shortest paths in unit-weight planar graphs". En the 45th annual ACM symposium. New York, New York, USA: ACM Press, 2013. http://dx.doi.org/10.1145/2488608.2488702.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Sun, M., Z. X. Yang, N. Guo y R. J. Jardine. "Three-Dimensional DEM Simulation of Plugging Behaviour of Small-Diameter Open-Ended Model Piles Penetrating Into Sand". En Innovative Geotechnologies for Energy Transition. Society for Underwater Technology, 2023. http://dx.doi.org/10.3723/joia5398.

Texto completo

Resumen

It is known that plugging behaviour plays a significant role in affecting the bearing capacity of open-ended piles driven in sands. However, numerical analyses of pile plugging presents multiple challenges. To better understand plugging development during open-ended pile installation, three-dimensional discrete element method (DEM) simulations have been undertaken of small model piles' penetration in virtual calibration chamber tests. The analyses employed the open-source MUSEN framework and took advantages of graphics processing unit (GPU) acceleration, particle refinement and axisymmetric modelling. The simulation was able to reproduce pile plugging behaviour in sands ranging from fully coring to fully plugged states. The contributions to pile capacity of internal and external shaft friction are correlated with plug indices including incremental filling ratio (IFR) and plug length ratio (PLR). The new, purely theoretical, analyses show shaft resistances that agree well with estimates made from well-known CPT-based offshore design methods. The poorer agreement found for base resistances also identified ways in which the new DEM analyses may be improved.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Campanari, Stefano, Luca Boncompagni y Ennio Macchi. "Microturbines and Trigeneration: Optimization Strategies and Multiple Engine Configuration Effects". En ASME Turbo Expo 2002: Power for Land, Sea, and Air. ASMEDC, 2002. http://dx.doi.org/10.1115/gt2002-30417.

Texto completo

Resumen

This paper investigates energy savings and economic aspects related to the use of microturbine generators in commercial buildings either for cogeneration (electricity+heat) or for trigeneration (electricity, heat and cold). In all calculations, reference is made to a 25 kWel–class commercial micro-turbine generator (MTG), tested by the authors. Various plant schemes are considered, based on one or several MTG sets. The possibility of generating heat and/or cold also by an electrically driven inverse-cycle air-to-water heat pump/chiller system is also considered. Calculations are based on the simulation code TRIGEN developed by the authors. The code provides detailed energy, economic and emission yearly balances. The plant operating mode is optimized in each time interval. The results indicate that, due to large load variations, (i) the optimum turbine nominal output is in the range of about 70% of the electric peak demand, (ii) energy savings are marginal, (iii) advantages related to splitting the overall capacity on more than one unit are marginal and (iv) the addition of an absorption machine improves the plant economics.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Patrão, Caroline, Luis Kowada, Diane Castonguay, André Ribeiro y Celina Figueiredo. "Some exact values for the diameter in Cayley graph Hl,p". En IV Encontro de Teoria da Computação. Sociedade Brasileira de Computação - SBC, 2019. http://dx.doi.org/10.5753/etc.2019.6395.

Texto completo

Resumen

The family of graphs H,p has been defined in the context of edge partitions. The established properties such as vertex transitivity and low diameter suggest this family as a good topology for the design of interconnection networks. The vertices of the graphH p are the tuples with values between 0 and p1, such that the sum of the values is a multiple of p, and there is an edge between two vertices, if the two corresponding tuples have two pairs of entries whose values differ by one unit. In order to work towards the diameter, the difference between an upper and a lower bounds is established to be at most and we present subfamilies of graphs H p such that, for several values of and p, the bounds are tight.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Mellal, I., V. Rasouli, A. Dehdouh, A. Letrache, C. Abdelhamid, M. L. Malki y O. Bakelli. "Formation Evaluation Challenges of Tight and Shale Reservoirs. A Case Study of the Bakken Petroleum System". En 57th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2023. http://dx.doi.org/10.56952/arma-2023-0894.

Texto completo

Resumen

ABSTRACT Several challenges are associated with enhancing oil and gas recovery from tight and shale reservoirs, which make up a significant portion of hydrocarbon production worldwide. Despite past efforts to characterize the properties of these reservoirs using different techniques, several geological, geochemical, and geological properties of such formations remain challenging to determine accurately. To investigate these challenges, the Bakken Petroleum System (BPS) is taken as a case study, consisting of two source rock units and two tight reservoir units. A petrographic analysis using core slabs was done and a petrophysical model was built using conventional and advanced logs to estimate properties such as porosity, permeability, water saturation, mineralogy, movable and irreducible fluids, and pore size distribution. Challenges arise from the complexity of the formation, limitations of logging tools, and inaccuracies in estimation methods. Thin laminas and borrowed intervals are difficult to detect from well logs, leading to an incorrect reading of different well logs. Additionally, cementing material and variable volumes of minerals along the reservoir interval make the estimation of cementing exponent constant inaccurate. The salinity of water, dispersed clays, and clays coatings on grains lead to low resistivity readings. Also, permeability is independent of porosity and controlled by uniform pore throat and body size distribution. The study presents lessons learned from characterizing the complex BPS and challenges that can be used to accurately characterize other tight and shale reservoirs worldwide. INTRODUCTION Unconventional reservoirs are increasingly explored and exploited as conventional reserves decline. Shale and tight reservoirs account for 42% of total U.S. hydrocarbon reserves (EIA). Despite these huge reserves, less than 10% of the original oil in place (OOIP) can be technically and economically produced from these reservoirs using multistage hydraulic fracturing due to the low porosity and permeability, complex pore structure, and high variation in the mineralogy of these reservoirs(Abdeldjalil et al., 2023; Helms et al., 2023; Merzoug et al., 2022; J. Sorensen et al., 2014). Several enhanced oil recovery methods have been tested to investigate the factors affecting oil recovery from pore to field scale. This requires detailed understanding of rock and fluid properties at different scales for accurate modeling of subsurface fluid flow for EOR and gas storage (J.A. Harju, et al. 2022). Multiple challenges prevent accurate evaluation of the reservoir's rock and fluid properties distribution. This is due to various pore size and type distribution, mineralogy variation, different cementing minerals, thin beds, bioturbations, and existence and distribution of organic matter (Onwumelu et al., 2021). Geologic, petrographic and petrophysical analysis are the main common methods used to characterize reservoirs at different scales, This involves the identification of the main geologic features (grain size distribution, bioturbations, laminations and lithofacies), petrophysical properties (porosity, permeability, fluids, kerogen, and minerals volumes, pore size distribution), and pore characteristics (pore type and size, pore throat size distribution, grain sorting, and cementing materials). The accuracy and applicability of these methods are highly dependent on the scale of evaluation and the complexity of the reservoir.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Zeng, Qingna, Donghui Wang, Fenggang Zang, Yixiong Zhang, Bihao Wang y Zhihao Yuan. "Disorders in Fluid Filled Pipeline Structure With Elastic Helmholtz Resonators". En 2022 29th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/icone29-93421.

Texto completo

Resumen

Abstract This paper studies the influence of hybrid disorders on acoustic transmission characteristic in pipeline with periodic elastic HRs. Band gap structures (BGs) for infinite period are investigated by transfer matrix method and finite element method respectively, and fit well with the corresponding transmission loss (TL) for finite regular periods. By introducing a certain degree of uncertainty level, Interval analysis method is used to convert uncertain parameter problems into two deterministic models. Frequency response function (FRF) for near-periodic structure with single disorder and BGs for quasi-periodic structure with multiple disorders considering cavity radius and periodic length are investigated. The existence of disorders in periodic structure would always reduce attenuation interval and intensity, some disturbance would even change the original acoustic transmission characteristic and excite completely new attenuation zones. The sensitivity of pipeline acoustic vibration transfer characteristic to disorder parameter depends on attenuation mechanism, as for periodic elastic HRs pipeline, acoustic propagation stability is more sensitive to characteristic of locally resonant unit. The work in this paper enriches the stability analysis of pipeline with elastic HRs, which would provide theoretical reference for noise and vibration reduction design in practical engineering applications.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Bartkowiak, Tomasz. "Characterization of 3D Surface Texture Directionality Using Multi-Scale Curvature Tensor Analysis". En ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-71609.

Texto completo

Resumen

Anisotropy of surface texture can in many practical cases significantly affect the interaction between the surface and phenomena that influence or are influenced by the topography. Tribological contacts in sheet forming, wetting behavior or dental wear are good examples. This article introduces and exemplifies a method for quantification and visualization of anisotropy using the newly developed 3D multi-scale curvature tensor analysis. Examples of a milled steel surface, which exhibited an evident anisotropy, and a ruby contact probe surface, which was the example of isotropic surface, were measured by the confocal microscope. They were presented in the paper to support the proposed approach. In the method, the curvature tensor T is calculated using three proximate unit vectors normal to the surface. The multi-scale effect is achieved by changing the size of the sampling interval for the estimation of the normals. Normals are estimated from regular meshes by applying a covariance matrix method. Estimation of curvature tensor allows determination of two directions around which surface bends the most and the least (principal directions) and the bending radii (principal curvatures). The direction of the normal plane, where the curvature took its maximum, could be plotted for each analyzed region and scale. In addition, 2D and 3D distribution graphs could be provided to visualize anisotropic or isotropic characteristics. This helps to determine the dominant texture direction or directions for each scale. In contrast to commonly used surface isotropy/anisotropy determination techniques such as Fourier transform or autocorrelation, the presented method provides the analysis in 3D and for every region at each scale. Thus, different aspects of the studied surfaces could clearly be seen at different scales.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Enikov, Eniko T., Péter P. Polyvás, Gholam Peyman y Sean Mccafferty. "Tactile Eye Pressure Measurement Through the Eyelid". En ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-50875.

Texto completo

Resumen

This article presents the early results from a 10-person human subject study evaluating the accuracy of a novel method of indirect estimation of intraocular pressure using tactile sensors. Manual digital palpation tonometery is an old method used to estimate the eye pressure through palpation with ones fingers. Based on this concept, we present an instrumented measurement method, where multiple tactile stiffness sensors are used to infer the intraocular pressure of the eye. The method is validated using experimental data gathered from human subjects with eye pressures from 15 to 22 mmHg and determined by Goldman applanation tonometry (GAT). Bland-Altman plots comparing the GAT measurements and the proposed through-the-eye-lid tonometry indicate a statistical error of 5.16 mmHg, within the 95% confidence interval, which compares favorably with the FDA-mandated error bound of 5 mmHg. Details on the unit operation and data filtering are also presented. Due to its indirect and non-invasive nature, the proposed new tactile tonometry method can be applied at home as a self-administered home tonometer for management of glaucoma.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Matzenauer, Mônica, Renata Reiser y Helida Santos. "An approach for consensual analysis on Typical Hesitant Fuzzy Sets via extended aggregations and fuzzy implications based on admissible orders". En Workshop-Escola de Informática Teórica. Sociedade Brasileira de Computação, 2021. http://dx.doi.org/10.5753/weit.2021.18937.

Texto completo

Resumen

Typical Hesitant Fuzzy Logic (THFL) is founded on the theory of Hesitant Fuzzy Sets, which consider as membership degrees the finite and non-empty subsets of the unit interval, called Typical Hesitant Fuzzy Elements (THFE). THFL provides the modelling for situations where there exists not only data uncertainty, but also indecision or hesitation among experts about the possible values for preferences regarding collections of objects. In order to reduce the information collapse for comparison and/or ranking of alternatives in the preference relationships, this thesis develops new ideas on THFL connectives, investigated under the scope of three admissible orders. In particular, properties of negations and aggregations are studied, as t-norms and OWA operators, with special interest in the axiomatic structures defining the implications and preserving their algebraic properties and representability. As the main contribution, we present a model that formally builds consensus measures on THFE through extended aggregation functions and fuzzy negation, using admissible orders for comparison and further, differentiating an analysis of consistency over preference matrices. Main theoretical results are submitted to multiple expert and mutiple criteria decision making problems.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Ofrecemos descuentos en todos los planes premium para autores cuyas obras están incluidas en selecciones literarias temáticas. ¡Contáctenos para obtener un código promocional único!