Letteratura scientifica selezionata sul tema "Two-Layered logics"
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Articoli di riviste sul tema "Two-Layered logics":
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Brandl, Bernd, e Barbara Bechter. "The hybridization of national collective bargaining systems: The impact of the economic crisis on the transformation of collective bargaining in the European Union". Economic and Industrial Democracy 40, n. 3 (23 gennaio 2018): 469–89. http://dx.doi.org/10.1177/0143831x17748199.
Abstract (sommario):
In this article it is argued that the economic crisis has made national collective bargaining systems increasingly multi-layered, perforated and dynamically unstable, i.e. hybrid. The authors explain these transformations in terms of the concomitance of two different sources of change which do not necessarily follow the same logics. The first source stems from national systems’ endogenous logic of path dependency and the second from pressure to reform in accordance with exogenously applied strategies and logics. It is argued that these sources act like a whipsaw, pushing and pulling national collective bargaining systems between the two logics, leading to hybrid collective bargaining systems.
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Davis-Sikora, Diane, Rui Liu e Linda Ohrn-McDaniel. "BETA_S PAVILION". Journal of the International Association for Shell and Spatial Structures 63, n. 2 (1 giugno 2022): 115–21. http://dx.doi.org/10.20898/j.iass.2022.010.
Abstract (sommario):
BeTA_S pavilion is a 2.13m (7 ft) tall free-standing installation that employs biotensegrity logics characterized by networks of interconnected components and tendons with a shape adaptive capacity. The passively stable assembly responds to human touch through vibrational motion. The pavilion introduces a novel hybrid structural system with a two-way surface derived from a catenary archway composed of 385 regular tetrahedron modules connected in series by bands of pre-stressed CNC knit textile strips. Each tetrahedron consists of bending-active GFRP rods linked by custom 3D printed polylactide connectors. The pavilion's double layered surface is hydrophobic, using yarn made from recycled plastic bottles.
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Liu, B., X. X. Ren, Xian Zhang, Ping Li, Y. Dong e Zhi-Xin Guo. "Electric field tunable multi-state tunnel magnetoresistances in 2D van der Waals magnetic heterojunctions". Applied Physics Letters 122, n. 15 (10 aprile 2023): 152408. http://dx.doi.org/10.1063/5.0139076.
Abstract (sommario):
Magnetic tunnel junction (MTJ) based on van der Waals (vdW) magnetic layers has been found to present excellent tunneling magnetoresistance (TMR) property, which has great potential applications in field sensing, nonvolatile magnetic random access memories, and spin logics. Although MTJs composed of multilayer vdW magnetic homojunction have been extensively investigated, the ones composed of vdW magnetic heterojunction are still to be explored. Here, we use first-principles approaches to reveal that the magnetic heterojunction MTJs have much more distinguishable TMR values than the homojunction ones. In the MTJ composed of bilayer CrI3/bilayer Cr2Ge2Te6 heterojunction, we find there are eight stable magnetic states, leading to six distinguishable electronic resistances. As a result, five sizable TMRs larger than 300% can be obtained (the maximum TMR is up to 620 000%). Six distinguishable memories are obtained, which is two times larger than that of a four-layered homojunction MTJ. The underlying relationships among magnetic state, spin-polarized band structures, and transmission spectra are further revealed to explain the multiple TMR values. We also find that the magnetic states, and thus TMRs, can be efficiently modulated by an external electric field. This study opens an avenue to the design of high-performance MTJ devices based on vdW heterojunctions.
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Correia, Jorge, e Muath Taher. "Traditional Islamic cities unveiled: the quest for urban design regularity". Gremium 2, n. 4 (1 agosto 2015): 21–36. http://dx.doi.org/10.56039/rgn04a04.
Abstract (sommario):
Traditional Islamic cities have generally gathered orientalized gazes and perspectives, picking up from misconceptions and stereotypes that evolved during the seconf half of the 19th century and were perpectuated by colonialism. More recent scholarship has shed light on the urban organization and composition of such tissues; most of them confined to old quarters or historical centres of thriving contemporary cities within the Arab-Muslim world. In fact, one of the most striking features has been the unveiling of layered urban assemblages where exterior agents have somehow launched or interrupted an apparent islamicized continuum. Primarly, this paper wishes to search for external political factors that have designed regularly geometrized patterns in medium-sized Arab towns. For that, two case studies from different geographies - Maghreb and the Near East - will be morphologically analysed through updated urban surveys. Whereas Nablus (Palestine) ows the urban matrix of its old town to its Roman past, in Azemmour’s medina (Morocco) it is still possible to track the thin European early-modern colonial stratum. However, both cases show how regularity patterns challenge Western concepts of geometrical design to embrace levels of rationality related to tradional Islamic urban forms, societal configurations and built environment. Urban morphology becomes a fundamental tool for articulating the history with me processes of sedimentation and evolution in order to read current urban prints and dynamics. Thus, the paper will also interpret alternative logics of rational urban display in Azemmour and Nablus, linked to ways of living within the Islamic sphere.
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Kim, Kwang Baek. "Cloud-Type Classification by Two-Layered Fuzzy Logic". International Journal of Fuzzy Logic and Intelligent Systems 13, n. 1 (30 marzo 2013): 67–72. http://dx.doi.org/10.5391/ijfis.2013.13.1.67.
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Su, Guohui, Xing Wu, Wenqi Tong e Chungang Duan. "Two-Dimensional Layered Materials-Based Spintronics". SPIN 05, n. 04 (dicembre 2015): 1540011. http://dx.doi.org/10.1142/s2010324715400111.
Abstract (sommario):
The recent emergence of two-dimensional (2D) layered materials — graphene and transition metal dichalcogenides — opens a new avenue for exploring the internal quantum degrees of freedom of electrons and their potential for new electronics. Here, we provide a brief review of experimental achievements concerning electrical spin injection, spin transport, graphene nanoribbons spintronics and transition metal dichalcogenides spin and pseudospins. Future research in 2D layered materials spintronics will need to address the development of applications such as spin transistors and spin logic devices, as well as exotic physical properties including pseudospins-valley phenomena in graphene and other 2D materials.
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Jong-Hwan Kim, Jong-Hwan Park, Seon-Woo Lee e E. K. P. Chong. "A two-layered fuzzy logic controller for systems with deadzones". IEEE Transactions on Industrial Electronics 41, n. 2 (aprile 1994): 155–62. http://dx.doi.org/10.1109/41.293875.
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Liau, Teh Chau, Jin Jei Wu, Jian Qi Shen e Tzong Jer Yang. "Photonic Logic Gate Design Based on Frequency-Sensitive Optical Response of an EIT Photonic Crystal". Advanced Materials Research 301-303 (luglio 2011): 402–8. http://dx.doi.org/10.4028/www.scientific.net/amr.301-303.402.
Abstract (sommario):
The frequency-sensitive optical response due to two-photon resonance of electromagnetically induced transparency (EIT) in a tunable band structure of an EIT-based layered medium is considered. The unit cells of this periodic layered structure are composed of dielectric (e.g., GaAs) and EIT atomic vapor. The frequency-sensitive behavior of controllable reflectance and transmittance depending on the external control field can be applicable to new device design (e.g., it can serve as the fundamental working mechanism for photonic switches and photonic logic gates). Some two-input logic gates (e.g., OR and NAND gates) are designed based on the present effect of sensitive switching control that results from the two-photon resonance.
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Zhao, Yaning, e Chengyi Xia. "Crash behavior modeling and analysis on two interdependent networks". Modern Physics Letters B 35, n. 11 (17 febbraio 2021): 2150182. http://dx.doi.org/10.1142/s0217984921501827.
Abstract (sommario):
In real-world systems, one random failure or targeted attack may lead to the cascading destruction within a system, and even create the systemic collapse among multiple correlated ones. With the help of network science, modeling the cascade failure on complex networks has become a challenging topic. In this paper, we put forward an improved cascading model on two interdependent networks to further explore the impact of the specific detachment logic on the system collapse, where the distinct condition to leave the system for a pair of nodes exists on the two-layered networks. Meanwhile, once the detachment logic is satisfied, two different criteria are adopted to determine whether this pair of nodes will leave the interdependent networks. Through extensive numerical simulations, we analyze the effects of detachment logic, network topology, departure criteria and nodal coupling relationship between layers in detail. It is found that in our detachment logic, both criteria will render the whole system to exhibit the phenomenon of pseudo-steady state and sudden collapse. In particular, two critical thresholds to characterize the evolution of system crashing emerge, which is different from previous findings under other detachment logic conditions on two-layered networks. Current results are conducive to further understanding the crashing behaviors of interdependent networks and designing the more robust networked systems in practice.
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Scott, Joseph, Maysum Panju e Vijay Ganesh. "LGML: Logic Guided Machine Learning (Student Abstract)". Proceedings of the AAAI Conference on Artificial Intelligence 34, n. 10 (3 aprile 2020): 13909–10. http://dx.doi.org/10.1609/aaai.v34i10.7227.
Abstract (sommario):
We introduce Logic Guided Machine Learning (LGML), a novel approach that symbiotically combines machine learning (ML) and logic solvers to learn mathematical functions from data. LGML consists of two phases, namely a learning-phase and a logic-phase with a corrective feedback loop, such that, the learning-phase learns symbolic expressions from input data, and the logic-phase cross verifies the consistency of the learned expression with known auxiliary truths. If inconsistent, the logic-phase feeds back "counterexamples" to the learning-phase. This process is repeated until the learned expression is consistent with auxiliary truth. Using LGML, we were able to learn expressions that correspond to the Pythagorean theorem and the sine function, with several orders of magnitude improvements in data efficiency compared to an approach based on an out-of-the-box multi-layered perceptron (MLP).
Tesi sul tema "Two-Layered logics":
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KOZHEMIACHENKO, Daniil. "Paraconsistent and fuzzy modal logics for reasoning about uncertainty". Electronic Thesis or Diss., Bourges, INSA Centre Val de Loire, 2023. http://www.theses.fr/2023ISAB0014.
Abstract (sommario):
Ce manuscrit est dédié à l'étude des logiques modales floues qui formalisent le raisonnement (paraconsistant) sur l'incertitude. Ici, l'interprétation d'«information (données) incertain(es)» inclut toute combinaison des trois propriétés suivantes. Premièrement, l'information peur être quantifiée, i.e., la proposition est associée à un degré de vérité plutôt qu'une valeur de vérité. Deuxièmement, l'information peut être incomplète. Troisièmement, l'information peut être contradictoire.Toutes les logiques étudiees se divisent en deux groupes. Les plus «traditionnelles» dont la sémantique est construite sur des modèles de Kripke où les formules (et parfois, même des relations d'accessibilité) prennent des valeurs dans [0,1] constituent le premier groupe. Le second groupe contient des logiques dites «bi-stratifiées». Ici, le langage est composé de trois parties: la strate intérieure, la strate extérieure, et la modalité non-nichante. On interprète la modalité comme une mesure sur l'univers (e.g., une mesure de probabilité, fonction de croyance, fonction de plausibilité, etc.) correspondante au degré de (in)certitude de l'agent dans une proposition donnée. Le raisonnement sur cette (in)certitude est conduit dans la strate extérieure. Les cadres dans des logiques bi-stratifiées sont alors des ensembles munis de mesures.Chacun de ces deux genres de logiques correspond à l'une des façons d'interpréter l'incertitude. Dans le cas moins formel, nous utiliserons les logiques avec la sémantique de Kripke. Dans le cas plus formel où l'on assume que le degré de certitude se comporte comme une mesure d'incertitude concrète, nous utiliserons les logiques bi-stratifiéesThis dissertation is devoted to the study of fuzzy modal logics that formalise (paraconsistent) reasoning about uncertainty. The understanding of ‘uncertain information (data)’ here includes any combination of the following three characteristics. First, the information can be graded, i.e., the statement is equipped with a truth degree rather than a truth value. Second, the information can be incomplete. Third, the information can be contradictory.All the logics in question can be divided into two kinds. First, the more ‘traditional’ modal logics defined on [0,1]-valued Kripke models (possibly, with fuzzy accessibility relations) whose language includes modal operators interpreted as infima and suprema of values in the accessible states.The second kind of logics contains so-called ‘two-layered’ logics. In this framework, the language is divided into three parts: the inner layer, the outer layer, and the non-nesting modality. The idea is to use the inner-layer language to describe events, interpret the modality as a measure on the set of events (e.g., as a probability function, belief function, plausibility, etc.) corresponding to the degree of the agent's (un)certainty in a given event, and then reason about this (un)certainty in the outer-layer language. A frame in a two-layered logic is, thus, a set with a measure defined thereon.These two kinds of logics correspond to two ways of interpreting uncertainty. In the less formal one, we will be using the logics with the Kripke-frame semantics. In the more formal case where the degree of one's certainty or belief is assumed to behave as a concrete uncertainty measure, we will use the two-layered logics
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Fumagalli, Mattia. "A two-layered Knowledge Architecture for perceptual and linguistic Knowledge". Doctoral thesis, Università degli studi di Trento, 2017. https://hdl.handle.net/11572/369282.
Abstract (sommario):
The lack of generality is a structural weakness of knowledge representation formalisms. Here by lack of generality we mean the inability of any given representation to describe the infinite richness and diversity of the world and also its potentially infinite descriptions which are enabled by language. This lack of generality is the main cause of many of the difficulties encountered so far, just think of the problems which have arisen in the effort of creating reusable ontologies. In this thesis we propose a solution to the problem of generality which is based on the key idea that knowledge should not be modeled a priori, at design time, but it should continuously generated, adapted and evolved, from generation to usage. The thesis provides four main contributions: (i) a shared terminology for the characterization of concepts and for their computational representation; (ii) a formalization of the distinction between substance concepts and classification concepts; (iii) the integration of these two notions of concept into a general representation language that organizes them into a hierarchy of increasing abstraction of what is perceived, and (iv) a two-layered knowledge representation formalism, where the first layer allows to represent concepts, as the main devices for achieving generality, and where the second layer allows to represent concepts as the result of “adapting†a description to the current knowledge representation needs and requirements.
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Fumagalli, Mattia. "A two-layered Knowledge Architecture for perceptual and linguistic Knowledge". Doctoral thesis, University of Trento, 2017. http://eprints-phd.biblio.unitn.it/2721/1/PhD.Thesis.Mattia.Fumagalli.2017.Final.pdf.
Abstract (sommario):
The lack of generality is a structural weakness of knowledge representation formalisms. Here by lack of generality we mean the inability of any given representation to describe the infinite richness and diversity of the world and also its potentially infinite descriptions which are enabled by language. This lack of generality is the main cause of many of the difficulties encountered so far, just think of the problems which have arisen in the effort of creating reusable ontologies. In this thesis we propose a solution to the problem of generality which is based on the key idea that knowledge should not be modeled a priori, at design time, but it should continuously generated, adapted and evolved, from generation to usage. The thesis provides four main contributions: (i) a shared terminology for the characterization of concepts and for their computational representation; (ii) a formalization of the distinction between substance concepts and classification concepts; (iii) the integration of these two notions of concept into a general representation language that organizes them into a hierarchy of increasing abstraction of what is perceived, and (iv) a two-layered knowledge representation formalism, where the first layer allows to represent concepts, as the main devices for achieving generality, and where the second layer allows to represent concepts as the result of “adapting” a description to the current knowledge representation needs and requirements.
Capitoli di libri sul tema "Two-Layered logics":
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Bílková, Marta, Sabine Frittella, Daniil Kozhemiachenko e Ondrej Majer. "Two-Layered Logics for Paraconsistent Probabilities". In Logic, Language, Information, and Computation, 101–17. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-39784-4_7.
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Schmidtke, Hedda. "Towards a Fuzzy Context Logic". In Fuzzy Systems [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95624.
Abstract (sommario):
A key step towards trustworthy, reliable and explainable, AI is bridging the gap between the quantitative domain of sensor-actuator systems and the qualitative domain of intelligent systems reasoning. Fuzzy logic is a well-known formalism suitable for aiming at this gap, featuring a quantitative mechanism that at the same time adheres to logical principles. Context logic is a two-layered logical language originally aimed at pervasive computing systems for reasoning about and within context, i.e., changing logical environments. Both logical languages are linguistically motivated. This chapter uncovers the close connection between the two logical languages presenting two new results. First, a proof is presented that context logic with a lattice semantics can be understood as an extension of fuzzy logic. Second, a fuzzification for context logic is proposed. The resulting language, which can be understood as a two-layered fuzzy logic or as a fuzzified context logic, expands both fields in a novel manner.
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"Chapter Two: Logical Functions of Judgment and the Layered Solution". In The Aesthetic Use of the Logical Functions in Kant's Third Critique, 75–132. De Gruyter, 2018. http://dx.doi.org/10.1515/9783110576078-005.
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Heskett, John. "Futures". In Toothpicks and Logos, 190–202. Oxford University PressNew York, NY, 2002. http://dx.doi.org/10.1093/oso/9780192803214.003.0010.
Abstract (sommario):
Abstract Two themes have recurred throughout this book: the extent of variations in design practice, and the manner in which it is being affected by far-reaching changes in technology, markets, and cultures. Design cannot remain isolated from these wider patterns, but the situation is confused. As in previous historical phases of change, a point arrives at which consciousness of the extent of change becomes a pressing issue, but uncertainty about what will eventuate means few definitive answers are available. Since the early 1980s, attempts to adapt old forms and processes to new purposes have been juxtaposed with wild experiments and many overconfident pronouncements of what the future will be. If the basic proposition in this book is that design has evolved historically in a layered pattern, rather than a linear evolution in which new developments eliminate previous manifestations, then we can expect new layers to be added that will alter the role and relationships of pre-existing modes.
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Angelone, Erik. "A Corpus-Based Comparison of Self-Reflection Modalities in Process-Oriented Translator Training". In Handbook of Research on Teaching Methods in Language Translation and Interpretation, 346–61. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-6615-3.ch018.
Abstract (sommario):
In recent years, process-oriented translator training has gained popularity among trainers and trainees alike, thanks to new, user-friendly pedagogical tools geared towards fostering cognizance of problems and problem-solving. This chapter reports on a corpus-based exploratory study that set out to document variation in student problem-solving discourse when utilizing Integrated Problem and Decision Reporting logs and screen recordings as self-reflection tools. Variation was observed between the two self-reflection modalities, particularly in the domains of the textual level and locus (comprehension, transfer, or production) of problem solving. The discourse generated by students when using screen recording for self-reflection is suggestive of a multi-layered, granular approach, which may, in part, shed light on why screen-recording analysis has proven to be particularly efficacious for the purposes of error detection and mitigation.
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Kivle, Ineta. "Skaitļu polifonija: imitācija vai simulācija? 111111111 × 111111111 = 12345678987654321". In Izmērītais laiks un telpa, 15–24. LU Akadēmiskais apgāds, 2022. http://dx.doi.org/10.22364/ilt.22.02.
Abstract (sommario):
Number relates to intelligible reality: it gives a clear reference to quantity and demonstrates how mind is connected with sensitive world, or how numbers simulate self-referential codes and signs. Numbers as metaphysical order, element of ontological structures, measure of harmony, movement and transformation are applicable for comparison of various philosophical approaches. Philosophical approach seeks abstract and universal being of numbers that connotes with ideas, shapes, and forms – the number always is something definite. On the one hand, numbers are independent of capacities of subjective mind, whereas on the other, numbers are constituted by human mind as a measure of order, proportion, harmony, quantity, etc. As the main philosophical characterizations of number are considered the stances permeating all spectrum of human activities, elucidating functions of being and justifying rational order of the world, as well as constructed realities – simulacrum, hyperreality, digital world, etc. Simulation, as well as imitation relates to reality in different ways, it depends on what is thought by reality. Reality as being of actual existence always changes its horizons from real objects to images and words, from intellect and emotions to signs and images, from signs to signs, etc. Faculty of ancient cosmos to be imitated is not more real than hyperreality with its functions of simulation – they both are realities of philosophical environments of different cultures. The main difference between imitation and simulation confirms existence of two realities: one is concerned with human’s activities that imitate nature, cosmos and other peoples and make references from intelligible to sensitive, from perceptual world to intelligible; another is hyperreality with its own realm that is without references to real human life and activities. Ancient philosophy concerns several aspects of number from cosmic dimensions to sensitive and calculative world, reaching different realms of human activities – democracy and politics, music, harmony of spheres, sounds, rhythm, relationship between cosmos, music and mathematics, etc. Baudrillard creates a new condition of society that have no ground – that is hyperreality, simulacra determined by the force of the code of numeral correlations. Baudrillard gives the examples of consumer objects as codes and shows how one numeral correlation of signs is constituted by structural relations with other signs. Self-referentiality of signs stimulates a separation from real objects, coding systems manage society through signs and digital logic of code. Signs simulate signs, numbers simulate numeral codes – in such flux of data, the subjectivity of human is deconstructed. The concept of number shows two different models of society: one is hypostatic – coming upwards and downwards with a reference to another reality and respect to corresponding truth; the other is a horizontally generated multiplicity – the deconstruction of the real into details without references to another reality and rejection of corresponding truth. However, there is a common stance: Ancient Cosmos as well as Hyperreality are created exploring typical mathematical operations, where numbers justify stability and clear order of created realities. The question is: how do we see numbers in reality? The “polyphony of numbers” works differently in each of these realities. The generally accepted definition that polyphony forms a complex and multi-layered simultaneous process of different components applies equally to the imitation and simulation of numbers, as well as to ancient philosophy and postmodern theories of hyperreality. The difference is in the direction, sequence and understanding of polyphonic reality. The polyphony of numbers explains not only the realities of thoughts that can be separated in historical time, but also the different manifestations of numbers in sounds, colours, and objects. The primary resources of the study are Plato’ dialogues; Plotinus. The Enneads. Tractate On Number; Jean Baudrillard. Simulacra and Simulations.
Atti di convegni sul tema "Two-Layered logics":
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Pratumsuwan, Pornjit, e Siripun Thongchai. "A two-layered fuzzy logic controller for proportional hydraulic system". In 2009 4th IEEE Conference on Industrial Electronics and Applications (ICIEA). IEEE, 2009. http://dx.doi.org/10.1109/iciea.2009.5138715.
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S. Pereira, Marcos, e Bruno V. Adorno. "Manipulation Task Planning with Constrained Kinematic Controller". In Congresso Brasileiro de Automática - 2020. sbabra, 2020. http://dx.doi.org/10.48011/asba.v2i1.1276.
Abstract (sommario):
This paper addresses the integration of task planning and motion control in robotic manipulation, where automatically generated feasible manipulation sequences are executed by a controller that explicitly accounts for the task geometric constraints. To cope with the high dimensionality of the manipulation problem and the complexity of specifying the tasks, we use a multi-layered framework for task and motion planning adapted from the literature. The adapted framework consists of a high-level planner, which generates task plans for linear temporal logic specifications, and a low-level motion controller, based on constrained optimization, that allows to define regions of interest instead of exact locations while being reactive to changes in theworkspace. Thus, there is no low-level motion planning time added to the total planning time. Moreover, since there is no replanning phase due to motion planner failures, the robot actions are generated only once for each task because the search for a plan occurs on a static graph. We evaluated this approach with two pick-and-place tasks with similar complexity to the original framework and showed that the number of plan nodes generated is smaller than the one in the original framework, which implies less total planning time.
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Almheiri, Afra Naser, Subhrankar Paul, Shady Hassan, Carlos Barajas, Behdad Safaei, Mohamed Mahgoub e Guillaume Marie Cambois. "An Unprecedented Uplift in Seismic Imaging from an Ultra-Shallow Water Field, Offshore Abu Dhabi". In ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/211669-ms.
Abstract (sommario):
Abstract Offshore Abu Dhabi is characterized by ultra-shallow waters and thinly layered carbonate formations with high velocity and anisotropy contrasts. This produces complex recorded seismic wave-fields, riddled with noise and multiple energy, which are notoriously difficult to process. In a recent reprocessing project over a producing field offshore Abu Dhabi, we applied innovative processing techniques and obtained an unprecedented uplift in the final seismic image. 3D seismic data was acquired over the study area deploying airgun sources and 4-component receivers with ocean bottom cable (OBC) in an orthogonal cross-spread design. In vintage processing PZ summation was used to obtain the upgoing wavefield with the receiver ghost removed. 1D deconvolution was then applied to attenuate receiver-side pegleg multiples. Strong residual multiple energy nonetheless remained in the overburden and caused challenges in interpretation of the data. For the reprocessing, we applied a method known as up-down deconvolution, which is commonly used in deep water with a smooth water bottom. The implementation of up-down deconvolution in this ultrashallow water environment was challenging due to poor trace sampling and insufficient direct arrival energy in the shallow part of the recorded wavefield in the receiver domain. The mostly flat seafloor and horizontally stratified geology allowed us to implement the method in ultra-shallow water in the crossspread domain, with enhanced trace density. Further, we implemented a three-step method to model velocity and anisotropy parameters. We first used long offset seismic data to estimate effective velocity and anisotropy using a bi-spectral analysis method to pick non-hyperbolic moveout of the reflection data. Secondly, we independently measured Thomsen anisotropic parameters at seismic scale using available well logs and walk-away VSP data. These two independent methods provided an opportunity to build a simple layered anisotropy model. In the third step, we used reflection tomography to derive the final velocity and anisotropy models. The final model shows a wide variation of anisotropy within different geological layers of the survey area, where delta varies between -5% to 10% and epsilon varies between 0% to 40%. The shallow section exhibits high epsilon (30 to 40%) and negative delta values. The new seismic images provide a reliable interpretation of overburden structures. The Vertical Transverse isotropy (VTI) model shows consistency with sonic logs. The seismic images display high correlation with well synthetics at reservoir level. The reliability of the anisotropy model is confirmed by comparing a seismic structural depth map with well tops. The incorporation of anisotropy in incidence angle computation allows accurate angle stacks to be produced, which improves the reliability of subsequent AVO analysis. The workflow showcases the first successful implementation of up-down deconvolution in ultra-shallow waters to remove multiples, and reliable estimation of VTI parameters combining seismic and well data offshore Abu Dhabi.
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Pandey, Vikram Kumar, Permanand Dhermeshwar Thankur, Setiyo Pamungkas, Tony Thomas, Redha Al Lawatia, Magdy Samir, Talha Zubair e Abdul Bari. "Vertical Interference Testing as a Gateway to Permeability Anisotropy Demystification and Understanding Fluid Displacement in Carbonates". In SPE Reservoir Characterisation and Simulation Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/212646-ms.
Abstract (sommario):
Abstract Carbonates are infamous for their complex intrinsic heterogeneity, exaggerated due to stratification and layered geology. Characterization and correlation of this heterogeneity with recovery mechanisms becomes critical pertaining to Lower Cretaceous reservoir ‘A’ with over 4 decades of production/injection history. Hence, it is pertinent to systematically reduce the uncertainties associated with reservoir characterization by delineating high permeability streaks, permeability-contrasts, links between geological and petrophysical facies and their impact on field scale production/injection strategies. Emphasis was put on capturing downhole dynamic Kv/Kh profile across sub layers of the reservoir ‘A’, to enable assignment of representative values into reservoir simulation model with associated reservoir zonation. Vertical interference testing (VIT) was designed in a crestal location well with a history of near-by waterflooding, integrating simulator-based outputs with petrophysical and borehole image logs of an offset. Drawdown-buildup cycle was performed across source probe or packer, while simultaneous monitoring of pressure at observation probe. To reduce uncertainty and incorporate statistical sense into the data, multiple cycles of drawdown-buildup were conducted for vertical connectivity evaluation. In total, eleven VIT tests conducted with formation tester tool utilizing dual-straddle-packer and two-probe modules were interpreted implementing a systematic approach considering vertical communication as a function of geological facies and textural aspects from borehole images, geological information on fractures/faults, and surfaces. Interpretation involves identification of flow-units based on available logs, followed by identification of flow regimes (spherical/radial) to history-match data for estimation of horizontal and vertical permeabilities of each layer. Resultant analysis yielded insights on anisotropy by validating vertical communication through stylolite and across dense layers. Integration of VIT analysis results (Kh,Kv,Kv/Kh) with petrophysical logs led to the establishment of water flood advancement mechanism in this observation well at the crestal location of field. This establishes a critical link between integrated geological, textural and facies analysis in context of sedimentology, layering and rock quantified fabric permeability indicators visible on high vertical and horizontal resolution borehole image. Thereby, allowing derivation of scalable answer products and workflows. Subsequently, explaining water flood mechanism and enabling updating of simulation model for enhanced reservoir characterization. Furthermore, this also allows for field development augmentation and injection strategy optimization through linking of dynamic results to reservoir description of two major sub-layers of this giant carbonate field. Integration and analysis of key insights on vertical communication and carbonate anisotropy with major geological/petrophysical features aided in characterizing 3D static and dynamic models. This would allow improved trajectory planning of future wells, leading to improvement in recovery efficiency through guided injection strategy. Additionally, proactive data aggregation and insightful interpretation to help accelerate realization of value from field development strategy was highlighted.
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Troup, Duncan John, Muhammad Idham Khalid, Syahezat Ismail e Sathish Kumar Batulemai. "Cost Effective Plug And Abandonment Operations Through Acoustics Based Hydraulic Isolation Diagnostics". In SPE Asia Pacific Oil & Gas Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/210690-ms.
Abstract (sommario):
Abstract Presence of undesired and unplanned fluid movement in the wellbore is a major concern for operators through-out a well's life cycle. This happens when the barrier system of the well fails to provide the required isolation. Cemented sections are important barrier systems where failure of isolation can cause numerous issues such as emission to surface, undesired water production, depletion of gas drive mechanism, loss of production to the neighboring zones, contamination of freshwater sands and reservoir damage. Priorities are often given to ensure cement integrity during the plug and abandonment (P&A) phase to eliminate uncontrolled emission to surface post P&A. Deployment of two new generation acoustics technologies will enable operators to comprehensively identify these undesired/unplanned fluid movement in the wellbore and also indicate cement quality in annulus by running in tubing prior to P&A campaign in rig-less mode. The technology responsible to determine hydraulic seal consists of full-spectrum acoustics sensors that accurately identifies downhole leak or flow behind pipe through industry leading sensitivity & broadest frequency bandwidth sensors. The cement sheath quality meanwhile can be determined through deployment of multi-string isolation logging technology that provides multi-layer cement bond quality measurement. Unlike conventional cement bond logs and ultrasonic imaging logs which requires prior removal of production tubing from the wells, the multi string isolation logging technology diagnoses the cement sheath quality without the need to pull the tubing. Both of this technology can be deployed in the same run. The accurate assessment of cement bond and isolation conditions in multi-layered configurations not only reduces unnecessary costs, but significantly simplifies the traditional P&A process altogether. While many P&A operations can run as high as $500,000 per day, new generations acoustics based downhole leak and flow detection technology coupled with multi-layer cement bond quality measurement technology drastically reduces overall expenditure and ensures the most efficient operation process. It also paves the way in innovation for a wider range of rigless P&A solutions. The proposed technology are unique products of Archer and Probe. The combination run also indicate the value that can be generated from collaboration within technology providers in the industry.
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Wu, Hsu-Hsiang (Mark), Alan Cull, Li Pan, Clint Lozinsky, Matthew Griffing, Yijing Fan, Alban Duriez e Michael Bittar. "A New Generation of LWD Geosteering Electromagnetic Resistivity Tool Providing Multi-Layered Bed Boundary Detection, Anisotropy Determination, and Azimuthal Resistivity Measurements for Accurate Well Placement and Formation Evaluation". In 2022 SPWLA 63rd Annual Symposium. Society of Petrophysicists and Well Log Analysts, 2022. http://dx.doi.org/10.30632/spwla-2022-0049.
Abstract (sommario):
Over the past few years, ultra-deep electromagnetic (EM) resistivity tools have been primarily used to enable proactive geosteering and reservoir mapping. The ability to detect formation properties with a depth of investigation from 25 to 225 ft away from a wellbore enables optimization of well placement and helps to maximize reservoir exposure. As a result of the low frequencies and long spacings used by ultra-deep-reading tools, the corresponding inversion cannot resolve thinly bedded layers near the wellbore. Conventional azimuthal resistivity tools are then used to evaluate such missing details from the ultra-deep tools. Still, the conventional tools do not completely close the technology gap of providing high-fidelity, multilayer bed-boundary detection near the wellbore because of hardware limitations. A new generation of logging-while-drilling (LWD) geosteering resistivity tool is introduced, adopting enhanced antenna designs from the ultra-deep EM resistivity tool and comprising a shallow and a deep antenna collar. The shallow collar contains an antenna array of multiple coaxial transmitters and tilted receivers to produce azimuthal resistivities and geosignals. In addition, a pair of co-located, tilted transmitters enable formation anisotropy determination at any wellbore deviation. The deep collar is equipped with two tilted transmitters. By connecting the two collars, the system can detect formation bed boundaries within the range of 1 to 30 ft away from the wellbore, depending on the selected operating frequency and transmitter-to-receiver spacing. This paper discusses the design principle of the new generation resistivity tool. The design has three major advantages over existing resistivity technologies: tool measurements have a detection range of up to 30 ft to a formation bed boundary with a favorable resistivity contrast; the corresponding distance-to-bed-boundary (DTBB) inversion achieves very high resolution of thin layers near the wellbore; and the tool measures formation anisotropy and dip at any wellbore deviation. In addition, it provides greater signal-to-noise ratio (SNR) in its resistivity and geosignal measurements compared to previous designs. Several field trials have validated and exhibited the tool performance in calculating real-time resistivity anisotropy comparable to a 3D wireline induction reference. The trials also demonstrated azimuthal resistivity and geosignal measurements that matched other LWD resistivity tools, and a detection range of 1 to 30 ft for the multi-layered inversion, which matched offset well logs and real-time resistivity logs. Inversion results from deep to very shallow provide the flexibility to address a range of geosteering objectives and improve the economics of field development.
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Mosoiu, Ovidiu, Catalin Cioaca e Ion Balaceanu. "USING THE CAPITAL ASSET PRICING MODEL IN INFORMATION SECURITY INVESTMENTS". In eLSE 2018. Carol I National Defence University Publishing House, 2018. http://dx.doi.org/10.12753/2066-026x-18-220.
Abstract (sommario):
Interest in real option theory has intensified over the last decade due to the high uncertainty faced by some private and public organizations when deciding to make a strategic investment (competitive environment) or when faced with an external requirement of the organizational environment (ensuring security standards). Traditional methods of investment analysis define the existence of investment opportunity by net present value (NPV), ignoring the possibility that an investment will start from a certain moment in the future. In this way, it is not possible to capture the phenomenon in dynamics, which leads to limiting the possibility of solving the existing uncertainty over the time regarding the optimal use of resources. The need to optimize managerial strategies and give some flexibility to decision-makers in relation to the changes in the organization's external environment has triggered the real options analysis (ROA). By using ROA, a win-win situation is created in which the available policy options mitigate uncertainty fluctuations of updated net worth (based on new information available) and, at the same time, by applying the best strategy, maximize earnings. Information security systems are designed on a layered architecture and the decision to improve performance on each layer is the responsibility of strategic management. Being a modular system, it is recommended to build the architecture by stages, depending on the value of the assets. Also, the relatively long duration and costs of implementation, limited resources, irreversible character, and project risks determine the value and evaluation of the investment, involving its representation as a combined option associated with a succession of decisions. The proposed model is inspired from the theory of financial and real options, but also from the fuzzy logic. This approach seeks to anchor specific mechanisms for the study of asymmetric risk events in the security market (perfect market assumptions are of course limiting but provide a quick overview, which is essential for the proposed application). Using the capital asset pricing model (CAPM), the return on investments in the security of IT & C systems, by reference to the investment risk as the estimated value, is defined. Investors can take risks that can be broken down into two components: systematic risks and non-systemic risks. Systematic risk refers to the variability of income caused by external factors (macroeconomic conditions), being a measure of the relative market volatility of relative incomes. Unsystematic risk refers to income variability caused by unpredictable factors (mismanagement decisions, abrupt technologies overtaken). The depreciation of security investments is inherent and leads to the dilemma of small and frequent investments or major and rare investments. On this issue, the proposed model can provide solutions to decision-makers. Uncertainty, irreversibility, growth potential and competition are factors that influence the behavior and investment decision. We consider that by using the capital asset pricing model in the security investments associated with eLerning training systems, we can increase the precision of optimal investment in terms of risk and opportunity balancing.
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Gupta, Kinjal Dhar, Haibin Di e Aria Abubakar. "Automatic Estimation of Reservoir Properties Using 3D Machine Learning Workflow Independent of Well Alignment in the Presence of Geological Complexes". In ADIPEC. SPE, 2023. http://dx.doi.org/10.2118/216867-ms.
Abstract (sommario):
Abstract One of the most important steps for reservoir characterization is estimating its properties. The machine learning workflows developed in recent years to automate the process mostly capture 2D context of seismic and are capable of using information from vertical wells only. In this work we propose a new machine learning workflow to automatically estimate the properties that not only uses 3D seismic context in the presence of geological complexes but also is applicable to both vertical and deviated wells. Our proposed workflow consists of a machine learning model that estimates the property at each point of the survey by learning the 3D context around it. To build this model, 3D cubes of seismic and salt bodies are extracted around each point of the wells and fed as inputs into a multi-layered convolutional neural network architecture, with the corresponding properties at those well points as outputs. Once the model has been trained, it is used for estimating all properties at any point on the survey simultaneously by feeding it 3D cubes of seismic and salt bodies extracted around that point. To evaluate our method, we use the publicly available dataset from Groningen gas field. We train our model on 35 wells and use 4 other wells as test wells. We used seismic and salt as inputs and sonic and gamma ray logs as output. We observe that the predicted property values by our machine learning workflow for every test well match with the true property values of the wells, thus concluding that our workflow is capable of successfully estimating the properties automatically from seismic and salt information. We also observe that our workflow is capable of predicting properties at the well location that has no properties measured. As our workflow predicts properties at points, it can be used for both vertical and non-vertical wells. We also used the model to predict entire slices which pass through the test wells and observed that the distinct patterns followed by the predicted values coincide with the true values of the wells and the inputs, seismic and salt. The novelty of our approach involves two aspects. The first aspect is using the 3D context of seismic and salt as input. And the second aspect is estimating the properties only at points, thus generalizing the workflow across wells with various alignments – vertical or non-vertical.
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Pradhan, A., H. Al-Mayyan, D. Kamal, K. Ziyab, P. Nurafza, A. Srivastava, S. Mishra e T. Faulkner. "First Successful Execution of Miscible Gas Injection EOR Pilot in Kuwait: Challenges and Opportunities". In ADIPEC. SPE, 2023. http://dx.doi.org/10.2118/216693-ms.
Abstract (sommario):
Abstract A hydrocarbon gas injection pilot was successfully conducted in a heterogeneous multilayered Oolitic carbonate reservoir in Kuwait. The pilot strived towards de-risking technical and commercial feasibility for field-scale deployment of miscible CO2 WAG EOR development. The aim was to generate reliable unambiguous pilot performance results on remaining oil saturation, inflow profile and sweep efficiency to better quantify risks and uncertainties. This paper describes design, execution, and results of this pilot and its challenges and opportunities. The pilot was an inverted four-spot, consisted of a pre-flush water injection phase (2016-19), drilling and coring two fiberglass cased observation wells, followed by a gas injection phase (2021-2022). The phases were carried-out sequentially in three target layers, injecting a range of pore volumes in each layer. The pre-flush surveillance program included Inter-well water tracer test (IWTT), time-lapse saturation logging, coring, PLT/ILT, VIT, PGOR and ESP monitoring of the pilot wells. The gas injection phase surveillance in addition constituted gas tracers, pressure transient data and time-lapse saturation logging in the two observation wells to monitor the gas flood front movement. The immediate impact of this miscible gas injection pilot was the bolstering oil production increase and water-cut reduction in several pilot wells in relatively short pilot duration, persuading the management to high-grade CO2 full-field development as in-plan firm project. An integrated analysis of all the gathered data was conducted, providing an insight on reservoir de-saturation, inflow and sweep for the pre-flush and gas injection phases along with the achieved oil gain, assisting better understanding of the implications for future CO2 Water Alternating Gas (WAG) Enhanced Oil Recovery (EOR) full field pattern development. Detailed integrated static and dynamic modeling of the pilot area were conducted using compositional simulation models, incorporating pre-flush and gas injection phase data, history matched to production, injection, GOR, water-cut, pressure, tracer production concentration and arrival time, ILT/PLT and time-lapse saturation logs. This detailed assessment revealed the impact of heterogeneity including horizontal baffles and barriers on the displacement process. The water and gas tracer analysis provided a unique opportunity to conduct Residence Time Distribution (RTD) analysis to assess, quantify, and compare heterogenous flow patterns and swept volumes for both water and gas transport between well pairs in different reservoir layers. Novel integrated workflow consisting of robust surveillance techniques, reservoir modelling workflows along with tracer analysis techniques were used in this complex heterogeneous multi-layered carbonate reservoir study in understanding pore scale and reservoir scale sweep efficiency and its impact on oil recovery. The immediate increase in oil production in pilot and surrounding wells has provided KOC the much-needed opportunity in designing a road map for commercial deployment of CO2 WAG in this world class field.
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Aoun, Ala Eddine, Vamegh Rassouli, Youcef Khetib, Atir Kaunain, Olivia Kost e Abdelhakim Khouissat. "Technical Assessments of Horizontal Drilling with Multistage Fracturing to Increase Production from Hassi Tarfa Field, Algeria". In 56th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2022. http://dx.doi.org/10.56952/arma-2022-0886.
Abstract (sommario):
ABSTRACT: Unconventional resources have become the core business of many petroleum companies to meet the increasing demand for energy. Several technologies and methods have been developed and deployed to unlock the potential of tight and ultra-tight formations. Hassi Tarfa (HTF) oil field is a thin and tight sandstone reservoir in Algeria, with an average permeability of less than 0.5 mD. However, all drilled wells in this field are vertical. Hydraulic Fracturing (HF) is the prime stimulation technique that is applied to increase oil recovery in unconventional reservoirs. Although the well production tremendously increases after fracking operation, it does not sustain for longer period of time, which keeps the estimated ultimate recovery (EUR) to be relatively low. In this study, a reservoir model was built and history matched, in order to consider three scenarios to optimize the horizontal lateral length in the HTF field. Then, multistage HF design was simulated using advanced 3D finite element software and exported to the model to estimate the potential increase of EUR. Sensitivities on number of HF stages, fluid volumes, and proppant were conducted to identify the optimal number of HF stages. The results of this study showed that, employing multistage hydraulic fracturing along horizontal drilling can significantly improve the oil recovery in HTF formation. Fracture length and the number of stages showed to be important design parameters. This study also identified the optimal range of operational parameters such as pumping schedule, proppant mass and perforation interval which are crucial to the cost reduction and operation efficiency. 1. INTRODUCTION Global energy demand has increased considerably in the last decades due to the increase of the world population, manufacturing activities, and the high living standards, which calls for efficient energy recovery methods. Oil recovery factor from primary depletion for shale and tight formation has been predicted typically to be less than 10% (Alvarez et al, 2016). To overcome the resistance of the low to extremely low permeability to hydrocarbons flow from reservoir to bottom-hole, the petroleum industry has started implementing several enhanced oil recovery (EOR) mechanisms and technologies (Chemmakh et al., 2021; Ozotta et al., 2021). The combination of horizontal well drilling and multi-stage fracturing, and completion technologies has been the key, over the last two decades, to economically unlock the potential of unconventional reservoirs (Shengnan and Wang, 2012; Kegang et al, 2016). The horizontal section drilled maximizes exposure to the reservoir, while multi-stage fractures increase drainage area and build an effective connection between reservoir and horizontal wellbore. Cost effective Hydraulic Fracturing (HF) design is crucial to mobilize oil in tight formation. An integrated approach is essential to optimize fracture parameters using a reliable geomechanical model and reliable reservoir simulations to predict the post-fracture productivity (Rahman et al, 2014). The industry experience has showed that one third of the fractured clusters contribute with up to 75% of production. Far et al. (2015) observed that resulting production is lithology dependent and some specific variables correlate well with reservoir fracturability and production. The approach developed maximizes the use of well logs and cuttings analysis to determine where to place the frac stage and perforation clusters. Several studies had investigated the optimum horizontal length to maximize recovery. In the Bakken formation in the Williston Basin, USA for instance, the horizontal lateral length typically exceeds 10,000 ft with more than 30 HF stages. It is substantiated in literature that the various in lithology and geology lead to different optimal stage intervals, therefore different ultimate oil recovery. Wang et al. (2019) proposed an innovative approach to optimize horizontal well fracturing with great success. A set of seismic methods were implemented to accurately visualize the formation around the wellbore, select the best azimuth, frac location and direction. Recently, artificial intelligence has been widely implemented in the petroleum industry. Andrei and Connel (2019) applied fuzzy logic to build a data driven model, which was used to identify reservoir quality and eventually horizontal well placement. Likewise, Elkin et al. (2018) employed Monte Carlo technique to optimize horizontal well length. Al Shueili et al. (2022) presented the lessons learned about how to approach horizontal well multistage fracturing program in tight multi-layered and laminated reservoir. Based on the production model, they reported that four to five HF stages for 1000 m lateral length is sufficient to connect the required layers.