Academic literature on the topic 'Load Path Theory'
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Journal articles on the topic "Load Path Theory"
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Qiu, Gong An, Guoan Zhang, Xiao Ge Zhang, and Min Liu. "Safety Information Dissemination Path Prediction in High-Density Vehicular Wireless Networks." Advanced Materials Research 655-657 (January 2013): 1770–73. http://dx.doi.org/10.4028/www.scientific.net/amr.655-657.1770.
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Many safety applications needed safety warning information to be disseminated to all vehicles in an area quickly. A path prediction model was built from the fused evidences by evidence theory, in which the basic probability assignment function of the local load and the old path load could be achieved using fuzzy set. And the loads became the evidences of the dissemination path prediction respectively. The prediction result with the maximal confidence was regarded as the quasi-real-time dissemination path load. Simulations show that the average end-to-end delay of safety information under heavy load with path prediction is less than the half of the delay without path prediction. However, the average packets loss rate of two schemes is almost the same.
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Bai, Xin Lei, Li Ping Guo, and Liang Ze Liu. "Optimization Scheme of Load Transferring Path for Distribution Network." Applied Mechanics and Materials 494-495 (February 2014): 1656–59. http://dx.doi.org/10.4028/www.scientific.net/amm.494-495.1656.
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For the power distribution network load transferring path optimization problem, this paper focuses on optimization scheme of load transferring path based on the fast non-dominated storing genetic algorithm (NSGA-II) with elitist strategy, this proposed method can avoid the selection of weight and the preference of the solution, and the solution sets can highlight the essence of optimization problems, then the fuzzy theory and the entropy weight are employed to extract the comprehensive optimal solution. IEEE33 node system simulation results verify the effectiveness of the model and algorithm.
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Jie Gao and Li Zhang. "Load-balanced short-path routing in wireless networks." IEEE Transactions on Parallel and Distributed Systems 17, no. 4 (April 2006): 377–88. http://dx.doi.org/10.1109/tpds.2006.49.
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Gebhardt, Clemens, and Michael Kaliske. "Reliable simulation of timber structures by combined load and displacement control." Engineering Computations 32, no. 3 (May 5, 2015): 766–78. http://dx.doi.org/10.1108/ec-04-2014-0069.
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Purpose – The purpose of this paper is to propose a path-finding algorithm to solve problems with an arbitrary load-displacement relationship which results from geometrical and material nonlinear models to simulate e.g. timber structures realistically. Design/methodology/approach – A method using combined load and displacement control for the Newton method along with path-characterising measures and sub-incremention is introduced. A path-related stiffness measure is used to identify the situation when it is necessary to select the displacement control and chose the best degree of freedom as a parameter instead of the load factor. The nonlinearity index extracts information about the convergence behaviour during one incremental step. Together with the reduction of the load increments it avoids leaving the equilibrium path. Findings – The method is discussed based on numerical examples with highly nonlinear behaviour. It is capable to solve systems with decreasing load capacity and snap-back effects. Originality/value – The algorithm combines load and displacement control and adaptively choses the method and the corresponding degree of freedom and cares for reliable path following.
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Yang, Chao, Yansong Wang, Hui Guo, Jiang Lv, Ningning Liu, and Hongzhong Qi. "Vibration load and transfer path identification of vehicle using inverse matrix method based on singular value decomposition." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 234, no. 6 (November 22, 2019): 1703–13. http://dx.doi.org/10.1177/0954407019887887.
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Based on the theory of inverse transfer matrix, a novel method for simultaneous load identification of vehicle vibration is presented in this paper. Some response, excitation, reference points (called key points) and their transfer paths, which have severe effects on the vibration of a whole vehicle, are defined. The transfer functions among the key points are measured by experiments, and thereby a transfer function matrix of vehicle vibration is established. To solve ill-conditioning problem in the transfer function matrix, the methodology of singular value decomposition is introduced into matrix inversion in the excitation load identification. To reduce the identification error, four transfer function matrices with different reference points and condition numbers are selected and discussed. The results show that the more the reference points are, the smaller the condition number of transfer function matrix is, the higher the accuracy of excitation load identification. The transfer function matrix with minimum condition number is used to identify the excitation loads at the vehicle key points. Experimental verifications suggest that the newly proposed method is effective and feasible for excitation load identification of vehicle vibration. Using the identified excitation loads, furthermore, the vibration causes of the steering wheel and seat rail are obtained, which is helpful for improving vibration performance of the sample vehicle. In applications, the excitation load identification method proposed in this paper may be applied not only to other types of vehicle, but also to other complex electromechanical products for load identification in engineering.
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Liang, Ke, and Qin Sun. "Koiter’s Reduction Finite Element Method for Nonlinear Stability Analysis of Thin-Walled Shells." International Journal of Computational Methods 17, no. 01 (September 30, 2019): 1843004. http://dx.doi.org/10.1142/s0219876218430041.
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Thin-walled structures are widely used in aeronautical and aerospace engineering. Conical and cylindrical shells structures, under axial compression, are prone to failure by buckling and typically show a snap-back phenomenon in the end-shortening curve. Path-following technologies based on Newton-type methods have difficulties to trace reliably the snap-back response due to the extremely sharp turning angle near the limit point. In this paper, a Koiter’s reduction finite element method, termed the Koiter–Newton (KN) method, is presented to trace reliably the post-buckling path of cylinders and cones considering either linear buckling modes or dimples from lateral perturbation loads as geometric imperfection. A robust algorithm based on the bifurcation-detection technique is applied during the solution of the reduced order model to achieve a successful path-tracing. The numerical results presented reveal that the nonlinear prediction obtained from Koiter’s perturbation theory at the unloaded state of the structure is numerically accurate up to the buckling load and the initial post-buckling path.
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Yang, Bin, Qin Shou Huang, Ping Liang, and Hua Xu. "Simulation of Reflective Crack Propagation Path in Asphalt Overlay under the Partial Wheel Load." Advanced Materials Research 189-193 (February 2011): 2001–4. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.2001.
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Partial wheel load is one of the main causes that lead to shear-type reflective crack of asphalt overlay in the old cement concrete pavement. Based on the theory of fracture mechanics and finite element method, this paper focuses on the numerical simulation of the reflective crack propagation path in asphalt overlay under the partial wheel load. Calculation result and analysis show that reflective crack partially expands upwards at the side of wheel load under the effect of partial wheel load with a sequential increase of crack propagation length. As the crack propagation length increases, stress intensity factors grow rapidly in the early period, and then increase by degrees slowly and, in the later period, the amplitude grows increasingly. Stress and strain fields enhance as the reflective crack increases upwards and the crack propagation angle expands gradually with the increase of reflective crack propagation length.
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He, Longlong, Zhifang Liu, Junjie Gu, Jinliang Wang, and Kunfa Men. "Fatigue Crack Propagation Path and Life Prediction Based on XFEM." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 37, no. 4 (August 2019): 737–43. http://dx.doi.org/10.1051/jnwpu/20193740737.
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Based on the theory of linear elastic fracture mechanics, the relationships between material constants c3, c4 required in Abaqus and constants C, m in Paris formula are derived. Then extended finite element method (XFEM) of Abaqus software is used to is used to predict the crack propagation path and life of the plate with center inclined through crack and typical stiffened wing spar with initial crack under the constant amplitude fatigue load. The results show that the predicted crack propagation path is in good agreement with the experimental results, and the crack propagation life error is less than 6.3%. It also shows that this method can accurately predict the fatigue crack growth path and life of two-dimensional and three-dimensional complex structures under constant amplitude loads. This study can provide an effective way for damage tolerance analysis of structures and has certain engineering application value.
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Zhang, Jun Ping, Ai Rong Liu, Gang Wu, and Ke Zeng. "Study on Operating Vehicle Load Limit of Sub-Health Bridge." Advanced Materials Research 163-167 (December 2010): 3369–75. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.3369.
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Depending on the actual service condition of sub-health bridge, the following investigation is carried out: 1)The concept of damage limit state is proposed, from which the subject of the serviceability carrying capacity is revealed, then the evaluation path of serviceability carrying capacity of sub-health beam is given.2) The difference between the reliability of sub-health bridge and new bridge is analyzed, consequently, the problem about reasonable limit vehicle load is solved preliminarily in theory.
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Liu, Weiling. "Knowledge map: a creative visual path to library guides and resources." Electronic Library 38, no. 5/6 (November 26, 2020): 943–62. http://dx.doi.org/10.1108/el-03-2020-0055.
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Purpose This paper aims to indicate that library guides seem to be unfamiliar to most students or not easy to find or use. Some improvements have been made by embedding the guides in the learning management system or promoting the guides in formal library instructional classes. Are there other ways to promote or improve the use of library guides? The author proposes an exploratory visual solution to minimize this gap between library users and library guides. Design/methodology/approach Guided by the cognitive load theory, the proposed solution is a knowledge map created with Freeplane. The proposal is illustrated by comparing a sample knowledge map with its content source, a subject guide in LibGuides, via three browsing paths in locating a recommended database for a particular course on the sample subject guide website. Findings The knowledge map can display contents in different ways and provide a simple and visual layout with direct access to the library resources, which may help lessen users’ intrinsic cognitive load, minimize extraneous load or promote germane load. The map can also be beneficial to librarians for preparing teaching materials or guides management. Practical implications The proposed solution can be implemented with Freeplane based on existing library guides or created from scratch. Originality/value The proposed solution addresses a gap in the library field, where the use of knowledge maps for library services is overlooked.
Dissertations / Theses on the topic "Load Path Theory"
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Doncel, Josu. "Efficiency of distributed queueing games and of path discovery algorithms." Thesis, Toulouse, INSA, 2015. http://www.theses.fr/2015ISAT0007/document.
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Cette thèse porte sur l'efficacité des algorithmes distribués de partage des ressources et des algorithmes de découvert de chemin en ligne. Dans la première partie de la thèse, nous analysons un jeu dans lequel les utilisateurs paient pour utiliser une ressource partagée. La ressource allouée à un utilisateur est directement proportionnel à son paiement. Chaque utilisateur veut minimiser son paiement en assurant une certaine qualité de service. Ce problème est modélisé comme un jeu non-coopératif de partage des ressources. A cause du manque des expressions analytiques de la discipline de file d'attente sous-jacente, nous pouvons résoudre le jeu que sous certaines hypothèses. Pour le cas général, nous développons une approximation basée sur un résultat fort trafic et nous validons la précision de l'approximation numériquement.Dans la deuxième partie, nous étudions l'efficacité des jeux de balance de charge, c'est à dire, nous comparons la perte de performance de routage non coopératif décentralisé avec un routage centralisé. Nous montrons que le PoA est une mesure très pessimiste car il est atteint que dans des cas pathologiques. Dans la plupart des scénarios, les implémentations distribués de balance de charge effectuent presque aussi bien que la mise en œuvre centralisée optimale.Dans la dernière partie de la thèse, nous analysons problème de découverte chemin optimal dans les graphes complets. En ce problème, les valeurs des arêtes sont inconnues, mais peuvent être interrogés. Pour une fonction donnée qui est appliquée à des chemins, l'objectif est de trouver un meilleur chemin de valeur à partir d'une source vers une destination donnée interrogation le plus petit nombre de bords. Nous vous proposons le rapport de requête en tant que mesure de l'efficacité des algorithmes qui permettent de résoudre ce problème. Nous prouvons une limite inférieure pour ne importe quel algorithme qui résout ce problème et nous avons proposé un algorithme avec un rapport de requête strictement inférieure à 2This thesis deals with the efficiency of distributed resource sharing algorithms and of online path discovery algorithms. In the first part of the thesis, we analyse a game in which users pay for using a shared resource. The allocated resource to a user is directly proportional to its payment. Each user wants to minimize its payment while ensuring a certain quality of service. This problem is modelled as a non-cooperative resource-sharing game. Due to lack of analytical expressions for the underlying queuing discipline, we are able to give the solution of the game only under some assumptions. For the general case, we develop an approximation based on a heavy-traffic result and we validate the accuracy of the approximation numerically. In the second part, we study the efficiency of load balancing games, i.e., we compare the loss in performance of noncooperative decentralized routing with a centralized routing. We show that the PoA is very pessimistic measure since it is achieved in only pathological cases. In most scenarios, distributed implementations of load-balancing perform nearly as well as the optimal centralized implementation. In the last part of the thesis, we analyse the optimal path discovery problem in complete graphs. In this problem, the values of the edges are unknown but can be queried. For a given function that is applied to paths, the goal is to find a best value path from a source to a given destination querying the least number of edges. We propose the query ratio as efficiency measure of algorithms that solve this problem. We prove a lower-bound for any algorithm that solves this problem and we proposed an algorithm with query ratio strictly less than 2
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Payne, Rozetta Mary Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "A knowledge-based engineering tool for aiding in the conceptual design of composite yachts." Publisher:University of New South Wales. Mechanical & Manufacturing Engineering, 2008. http://handle.unsw.edu.au/1959.4/41229.
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Proposed in this thesis is a methodology to enable yacht designers to develop innovative structural concepts, even when the loads experienced by the yacht are highly uncertain, and has been implemented in sufficient detail to confirm the feasibility of this new approach. The new approach is required because today??s yachts are generally lighter, getting larger and going faster. The question arises as to how far the design envelope can be pushed with the highly uncertain loads experienced by the structure? What are the effects of this uncertainty and what trade-offs in the structural design will best meet the overall design objectives? The new approach provides yacht designers with a means of developing innovative structural solutions that accommodate high levels of uncertainty, but still focus on best meeting design objectives constrained by trade-offs in weight, safety and cost. The designer??s preferences have a large, and not always intuitive, influence on the necessary design trade-offs. This in turn invites research into ways to formally integrate decision algorithms into knowledge-based design systems. A lean and robust design system has been achieved by developing a set of tools which are blanketed by a fuzzy decision algorithm. The underlying tool set includes costing, material optimisation and safety analysis. Central to this is the innovative way in which the system allows non-discrete variables to be utilized along with new subjective measures of structural reliability based on load path algorithms and topological (shape) optimisation. The originality in this work is the development of a knowledge-based framework and methodology that uses a fuzzy decision making tool to navigate through a design space and address trade-offs between high level objectives when faced with limited design detail and uncertainty. In so doing, this work introduces the use of topological optimisation and load path theory to the structural design of yachts as a means of overcoming the historical focus of knowledge-based systems and to ensure that innovative solutions can still evolve. A sensitivity analysis is also presented which can quantify a design??s robustness in a system that focuses on a global approach to the measurement of objectives such as cost, weight and safety. Results from the application of this system show new and innovative structural solutions evolving that take into account the designers preferences regarding cost, weight and safety while accommodating uncertain parameters such as the loading experienced by the hull.
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Obeidat, Khaled Ahmad. "Design Methodology for Wideband Electrically Small Antennas (ESA) Based on the Theory of Characteristic Modes (CM)." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274730653.
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Pejhan, Khashayar. "The study of U* index theory for load transfer analysis and its application in design evaluation of vehicle components." 2017. http://hdl.handle.net/1993/32078.
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Load transfer analysis deals with an important function of engineering structure, which is the ability of structure in transferring imposed loads to the supporting points. Although stress value has proved to be an efficient index for performing the failure analysis, the necessity of defining an index for evaluation of structure stiffness has led to the introduction of the U* index theory. The U* index characterizes the internal stiffness distributions, as an indicator of the load transfer in the structure. Although U* index theory have been proven to be useful in design, it is missing necessary steps toward becoming a mature theory for structural analysis.
Firstly, the U* index theory needed to be examined and validated by experimental testing. Therefore, an experimental setup was proposed and tested, and U* index theory was validated through comparison of results.
Secondly, a systematic comparison between the conventional stresses analysis and the U* index analysis was lacking. Such comparison was made for structural analyses of a vehicle component. The results, also compared to observations of experimental testing showed that in some cases, application of conventional stress analysis might be limited or less precise.
Thirdly, design modification capability is a significant feature of the U* index theory, and it was necessary to demonstrate that real life problems can benefit from this potential. In this study, sample structures representing the components of multiple passengers carrying vehicles were selected and analyzed by U* index theory and design modifications were proposed and implemented on the structure.
Lastly, the U* index theory should be applicable to different types of problems, including nonlinear domain. Hence, to remove the limitations of linear analysis that is a part of the original theory, an extension of U* index theory to the nonlinear domain was proposed and tested.
In summary, U* index theory provides an understandable explanation of load transfer in the structure and provides a general awareness regarding structural performance. He presented work showed that the existing methods of structural analysis have limitations in certain aspects that can be overcome by combining the perspective of U* index analysis to the existing structural analysis paradigm.February 2017
Books on the topic "Load Path Theory"
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Parini, Jay. The Art of Teaching. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780195169690.001.0001.
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Becoming an effective teacher can be quite painful and exhausting, taking years of trial and error. In The Art of Teaching, writer and critic Jay Parini looks back over his own decades of trials, errors, and triumphs, in an intimate memoir that brims with humor, encouragement, and hard-won wisdom about the teacher's craft. Here is a godsend for instructors of all levels, offering valuable insight into the many challenges that educators face, from establishing a persona in the classroom, to fostering relationships with students, to balancing teaching load with academic writing and research. Insight abounds. Parini shows, for instance, that there is nothing natural about teaching. The classroom is a form of theater, and the teacher must play various roles. A good teacher may look natural, but that's the product of endless practice. The book also considers such topics as the manner of dress that teachers adopt (and what this says about them as teachers), the delicate question of politics in the classroom, the untapped value of emeritus professors, and the vital importance of a settled, disciplined life for a teacher and a writer. Parini grounds all of this in personal stories of his own career in the academy, tracing his path from unfocused student--a self-confessed "tough nut to crack"--to passionate writer, scholar, and teacher, one who frankly admits making many mistakes over the years. Every year, thousands of newly minted college teachers embark on their careers, most with scant training in their chosen profession. The Art of Teaching is a perfect book for these young educators as well as anyone who wants to learn more about this difficult but rewarding profession.
Book chapters on the topic "Load Path Theory"
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Bogushevsky, Denis, Pavel Mikheev, Pavel Pristupa, and Serguey Suschenko. "The Time-Out Length Influence on the Available Bandwidth of the Selective Failure Mode of Transport Protocol in the Load Data Transmission Path." In Developments in Language Theory, 120–31. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-99447-5_11.
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Millitzer, Jonathan, Jan Hansmann, Giovanni Lapiccirella, Christoph Tamm, and Sven Herold. "Tuning and Emulation of Mechanical Characteristics – Tunable Mounts and a Mechanical Hardware-in-the-Loop Approach for More Efficient Research and Testing." In Lecture Notes in Mechanical Engineering, 129–44. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-77256-7_12.
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AbstractNumerical simulations offer a wide range of benefits, therefore they are widely used in research and development. One of the biggest benefits is the possibility of automated parameter variation. This allow testing different scenarios in a very short period of time. Nevertheless, physical experiments in the laboratory or on a test rig are still necessary and will still be necessary in the future. The physical experiments offer benefits e.g. for very complex and/or nonlinear systems and are needed for the validation of numerical models.Fraunhofer LBF has developed hardware solutions to bring the benefit of rapid and automated parameter variation to experimental environments. These solutions allow the tuning and emulation of the mechanical properties, like stiffness, damping and eigenfrequencies of structures.The work presents two approaches: First a stiffness tunable mount, which has been used in laboratory tests in the field of semi-active load path redistribution. It allowed the researcher to test the semi-active system under different mechanical boundary conditions in a short period of time. Second, a mechanical Hardware-in-the-loop (mHIL) approach for the NVH development of vehicles components is presented. Here a mHIL-system is used to emulate the mechanical characteristics of a vehicle’s body in white in a wide frequency range. This allows the experimental NVH optimization of vehicle components under realistic boundary conditions, without actually needing a (prototype) body in white.
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Chatterjee, Ahan. "A Decadal Walkthrough on Energy Modelling for Cloud Datacenters." In Impacts and Challenges of Cloud Business Intelligence, 195–204. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-5040-3.ch012.
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Cloud computing is the growing field in the industry, and every scale industry needs it now. The high scale usage of cloud has resulted in huge power consumption, and this power consumption has led to increase of carbon footprint affecting our mother nature. Thus, we need to optimize the power usage in the cloud servers. Various models are used to tackle this situation, of which one is a model based on link load. It minimized the bit energy consumption of network usage which includes energy efficiency routing and load balancing. Over this, multi-constraint rerouting is also adapted. Other power models which have been adapted are virtualization framework using multi-tenancy-oriented data center. It works by accommodating heterogeneous networks among virtual machines in virtual private cloud. Another strategy that is adopted is cloud partitioning concept using game theory. Other methods that are adopted are load spreading algorithm by shortest path bridging, load balancing by speed scaling, load balancing using graph constraint, and insert ranking method.
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Singh, Anne-Marie, and Slava Kalyuga. "Enhancing the Effectiveness of Educational Hypermedia." In Advances in Game-Based Learning, 387–409. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-5225-0125-1.ch016.
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With advancement in technology, hypermedia learning environments are becoming more common in education. Such environments present the multiple representations of information in a non-linear and non-sequential format, allowing the learners to enhance their retention and transfer of knowledge by selecting and sequencing their learning paths. Research into expert-novice differences has suggested that learner prior knowledge has major implications for learning. This chapter considers the role of learner prior knowledge in enhancing the effectiveness of hypermedia learning from a cognitive load perspective. Cognitive load theory is an instructional theory that investigates instructional means of managing limitations of human cognitive system, primarily processing limitations of working memory. The chapter reviews recent studies of cognitive load theory-generated techniques for learners with different levels of prior knowledge and relevant research in hypermedia learning. The chapter concludes with evidence-based recommendations for enhancing the effectiveness of educational hypermedia.
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Kapuria, S., P. C. Dumir, and A. Ahmed. "Assessment of a layerwise theory of hybrid beams for patch load." In Computational Fluid and Solid Mechanics 2003, 370–73. Elsevier, 2003. http://dx.doi.org/10.1016/b978-008044046-0.50091-9.
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T, Tamilarasi, and M. Prasanna. "Research and Development on Software Testing Techniques and Tools." In Encyclopedia of Information Science and Technology, Fourth Edition, 7503–13. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-2255-3.ch653.
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Software Testing is the pre-eminent part of the software development life cycle process. It is the process of evaluating system or its components with the specified requirements or not. It is important process by means of accessing the quality of software, reusability and traceability of the requirements specified. There are many number of testing techniques and tools available for this task. Software testing is an essential part of research and lot of development has been made in this field. In this chapter, testing techniques and tools including test design tools, load and performance testing tools, test management tools, test implementation tools, test evaluation tools, static analysis tools, Basic path testing, Loop testing, Control structure testing, code based techniques, Path testing, data flow testing, syntax testing has been described. Some distinctive latest research and development in testing strategy have been summarized.
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T, Tamilarasi, and M. Prasanna. "Research and Development on Software Testing Techniques and Tools." In Advances in Computer and Electrical Engineering, 1479–93. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-7598-6.ch109.
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Software testing is the pre-eminent part of the software development life cycle process. It is the process of evaluating system or its components with the specified requirements or not. It is important process by means of accessing the quality of software, reusability, and traceability of the requirements specified. There are many number of testing techniques and tools available for this task. Software testing is an essential part of research and lot of development has been made in this field. In this chapter, testing techniques and tools including test design tools, load, and performance testing tools, test management tools, test implementation tools, test evaluation tools, static analysis tools, basic path testing, loop testing, control structure testing, code-based techniques, path testing, data flow testing, syntax testing has been described. Some distinctive latest research and development in testing strategy have been summarized.
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Huang, Lican. "Virtual Hierarchical Tree Grid Organizations (VIRGO)." In Handbook of Research on P2P and Grid Systems for Service-Oriented Computing, 711–31. IGI Global, 2010. http://dx.doi.org/10.4018/978-1-61520-686-5.ch030.
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The currently two types of main P2P technologies–unstructured and structured approaches do not care about the semantic meaning of the nodes. They do not care about the nodes whose users may take different roles in social groups in the communities. Here, a semantic P2P Network-Virtual Hierarchical Tree Gird Organizations (VIRGO) is described. VIRGO is a hybrid of unstructured P2P and structured P2P technologies by merging a multi-tuple Virtual Hierarchical Overlay Network and random cached network. It has the following properties: Decentralization--VIRGO is fully distributed, robust, and easy-managed; Load balance–Cached nodes in route table help to solve the problem of the load balance in the tree structure; Scalability--Time complexity, space complexity and message-cost of lookup protocol of VIRGO is O (logN), where N is the total number of nodes in the network; Availability–There is at least one path between every two nodes. This chapter gives audience the concepts, framework, protocols and applications about Virtual Hierarchical Tree Gird Organizations (VIRGO). It will point out why VIRGO should exist among lots of P2P technologies
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Bhattacharyya, Mitun, Ashok Kumar, and Magdy Bayoumi. "System Framework and Protocols for Ubiquitous Computing Based Monitoring of an Oil Platform." In Designing Solutions-Based Ubiquitous and Pervasive Computing, 138–57. IGI Global, 2010. http://dx.doi.org/10.4018/978-1-61520-843-2.ch007.
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This book chapter proposes a system based on the WirelessHART standard for monitoring and controlling oil platforms using sensor networks. The authors propose a hierarchical distributed system where sensor nodes and process components are grouped both functionally and in terms of proximity (i.e., spatially). They harness the existing electrical powering supplies to some of the process components to enhance our network routing protocol. They also propose a component based addressing scheme. Then propose a hybrid routing protocol having proactive paths for high priority data and reactive paths for low priority that can help in load balancing and thus improving the lifetime of the sensor network. Finally, the authors discuss about methodologies for assessing the health (residual energy) of the sensor network system. Related research is discussed at appropriate points.
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Koch, Christof. "Linear Cable Theory." In Biophysics of Computation. Oxford University Press, 1998. http://dx.doi.org/10.1093/oso/9780195104912.003.0008.
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In the previous chapter, we briefly met some of the key actors of this book. In particular, we introduced the RC model of a patch of neuronal membrane and showed an instance where such a “trivial” model accounts reasonably well for the input-output properties of a neuron, as measured at its cell body. However, almost none of the excitatory synapses are made onto the cell body, contacting instead the very extensive dendritic arbor. As we will discuss in detail in Chap. 3, dendritic trees can be quite large, containing up to 98% of the entire neuronal surface area. We therefore need to understand the behavior of these extended systems having a cablelike structure. The basic equation governing the dynamics of the membrane potential in thin and elongated neuronal processes, such as axons or dendrites, is the cable equation. It originated in the middle of the last century in the context of calculations carried out by Lord Kelvin, who described the spread of potential along the submarine telegraph cable linking Great Britain and America. Around the turn of the century, Herman and others formulated the concept of Kemleitermodel, or core conductor model, to understand the flow of current in nerve axons. Such a core conductor can be visualized as a thin membrane or sheath surrounding a cylindrical and electrically conducting core of constant cross section placed in a solution of electrolytes. The study of the partial differential equations describing the evolution of the electrical potential in these structures gave rise to a body of theoretical knowledge termed cable theory. In the 1930s and 1940s concepts from cable theory were being applied to axonal fibers, in particular to the giant axon of the squid (Hodgkin and Rushton, 1946; Davis and Lorente de No, 1947). The application of cable theory to passive, spatially extended dendrites started in the late 1950s and blossomed in the 1960s and 1970s, primarily due to the work of Rail (1989). In an appropriate gesture acknowledging his role in the genesis of quantitative modeling of single neurons, Segev, Rinzel, and Shepherd (1995) edited an annotated collection of his papers, to which we refer the interested reader. It also contains personal recollections from many of Rail's colleagues as well as historical accounts of the early history of this field.
Conference papers on the topic "Load Path Theory"
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Hachkowski, M., L. Peterson, and M. Lake. "Load path management design theory for precision deployable joints." In 41st Structures, Structural Dynamics, and Materials Conference and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2000. http://dx.doi.org/10.2514/6.2000-1364.
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Pejhan, Khashayar, Qingguo Wang, Christine Q. Wu, and Igor Telichev. "Extension of U* Index Theory to Nonlinear Case of Load Transfer Analysis." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51175.
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Load transfer analysis has been proved to be an effective approach for designing light weight vehicle structures in last two decades. There are two main procedures for predicting the load path in a vehicle: The stress trajectory method and the U* index theory. The first approach has shown some shortcomings in dealing with geometrical irregularities. As a result, automotive industries have mainly applied the U* index as a design tool to study the load transfer behavior in the vehicle structure. The U* index, is an indicator for the load transfer in the structure, i.e. higher U* index value indicates more significant role in the load transfer process. So, the distribution of the U* index in the structure can be used to predict the main load path in the structure. Nevertheless, this foundation of this theory is based upon the linear elasticity equations and consequently, it has always been limited to linear elastic problems in static or quasi static conditions. Eradicating this limitation and extending the U* Index theory to nonlinear elastic problems is the main objective of this study. An extension to nonlinear criteria for U* index theory is proposed in this paper. It is shown, for the very first time, that the extended nonlinear load transfer index (U*NL) is a true measure for the load transfer in the structure in a nonlinear elastic problem.
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Wang, Qingguo, Khashayar Pejhan, Christine Q. Wu, and Igor Telichev. "Load Transfer Index for Composite Materials." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51176.
Full textAbstract:
Load transfer analysis is a new paradigm for lightweight vehicle design. U* index has been proved to be an effective indicator for the load path. The U* theory indicates that the external loading mainly transfers through the parts with higher U* values in the structure. However, the fundamental equations of the theory are based on isotropic, homogenous, and linear elastic assumptions for the materials. Consequently, U* index is inadequate for composite materials which are increasingly used in automotive structures. In this study, a new load transfer index for composite structures, U*O, is proposed for the first time inspired by the basic U* theory. The U*O index considers the composite material as orthotropic instead of isotropic and eliminates the limitation of the basic U*. The effectiveness of the new U*O index on load path prediction is demonstrated by a case study for a general Graphite-epoxy lamina. The U*O index is capable to evaluate the accurate load path for the composite specimen. By contrast, the basic U* analysis shows the incorrect results.
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Krishnan, Girish, Charles Kim, and Sridhar Kota. "Load-Transmitter Constraint Sets: Part II—A Building Block Based Methodology for the Synthesis of Compliant Mechanisms." In ASME 2010 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/detc2010-28819.
Full textAbstract:
Designers have always conceptualized of load flow as a part of their initial design process for mechanisms and structures. However, the lack of mathematical representation of load flow makes it inappropriate to be included in systematic design processes. Load Transmitter Constraint (LTC) sets provide a mathematical framework for visualizing load paths in compliant mechanisms. In this paper we propose a systematic design methodology for compliant mechanisms by systematic combination of LTC sets. This enables the designer to conceptualize load flow and choose relevant LTC sets to enforce it. Apart from being intuitive this process gives an understanding of the importance of each member in the mechanism. Furthermore this theory enables accurate and deterministic design for given motion specification without the aid of extensive computation. In this paper we propose guidelines for the design of mechanisms with a single load flow path and multi load flow path, particularly relevant in shape morphing applications.
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Pejhan, Khashayar, Qingguo Wang, and Igor Telichev. "Experimental Study of U* Index Response to Structural and Loading Variations." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51181.
Full textAbstract:
Load transfer analysis tracks the path, on which the imposed load is being carried through the structure. Recently, vehicle structure designers have paid growing attention to this aspect of structural analysis for designing lighter vehicle structures that can efficiently carry the imposed loads with minimum weight. There are two main procedures for load transfer analysis in automotive engineering: 1) Stress trajectory method and 2) U* index theory. The former method faces some difficulties in following load path in structures with stress concentrations made by geometrical irregularities. As a result the U* index theory has been utilized more frequently in this area. This theory has shown exceptional capacities in following load transfer in the structure and has provided innovative tools for design modification in automotive industry. Although it can be shown mathematically that U* index quantifies the internal stiffness of the structure there has not been an experimental validation for that. Moreover, the term internal stiffness itself is not an easy concept to follow and it can be easily mistaken for the structural stiffness of the structure. As a result in the current paper two experimental testing procedures are presented to distinguish the internal stiffness, that can be quantified with U* index and the structural (conventional) stiffness of the structure. Through these experiments, for the first time, physical evaluation of U* index response to loading and structural variations can be performed.
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Akbarzadeh, A. H., M. Arian Nik, and D. Pasini. "Structural Analysis of Variable Stiffness Laminated Plates Using First-Order Shear Deformation Theory." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-39092.
Full textAbstract:
Constant and variable stiffness strategies have been developed to design a composite laminate. With the former, each layer is designed with straight fibers that have the highest stiffness and strength in the fiber direction. With the latter, on the other hand, the stiffness can change within each layer by placing the fibers along a curvilinear fiber path. A variable stiffness design results in improved structural performance, as well as opens up opportunities to search for trade-off among structural properties. During the manufacture of a variable stiffness design with Automated Fiber Placement, certain defects in the form of gaps and overlaps could appear within the laminate and affect the laminate performance. In this study, we use the first-order shear deformation theory to assess the effect of transverse shear stresses on the critical buckling load, free and forced vibration of a variable stiffness laminate with embedded defects, an issue so far rarely examined in literature. The governing differential equations for the static analysis are first derived. A semi-analytic solution is then obtained using the hybrid Fourier-Galerkin method and the numeric time integration technique. The eigenvalue analysis is also conducted to determine the fundamental frequency and critical buckling load of the plate. It is found that the behavior of a variable stiffness plate is much more affected by the shear stresses than a constant stiffness plate. Ignoring the effect of transverse shear stresses results in 34% error in the predicted buckling load of a variable stiffness laminate with overlaps and a length-to-thickness ratio of 10.
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Zhou, Hong, Swetha Minupuri, Shilpa Indroju, and Vasuda Gorti. "Five-Bar Cylinder-Crank Two-DOF Parallel Manipulators for Singularity-Free Path Generation." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-10408.
Full textAbstract:
Parallel manipulators have the merits of high stiffness, load-bearing, operation speed and precision positioning capabilities that are required in many industrial applications. The main challenges for parallel manipulators are their limited workspace and singularity-free path generation capability. This paper is focused on the singularity-free path generation of five-bar cylinder-crank two-DOF parallel manipulators. The linkage feasibility conditions are derived based on the elimination of dead point position within the workspace. The workspace is generated using the curve-enveloping theory. The singularity characteristics and linkage configurations are presented. The singularity-free path generation capability is analyzed. The performance index contours within the workspace are produced using the condition number of the manipulator Jacobian matrix. This paper shows that five-bar cylinder-crank two-DOF parallel manipulators can be used as effective singularity-free path generators if properly designed. The results of this paper provide a useful map for the proper design of this type of parallel manipulator.
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Ahmadian, M. T., and T. Pirbodaghi. "Dynamic Analysis of Orthotropic Laminated Composite Plate Under Axial Load on Elastic Foundation." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-14436.
Full textAbstract:
In this paper, free vibration analysis of laminated composite plates is carried out using first shear deformation theory and finite element method. Effect of axial tension and compression forces on the natural frequencies of the structure is investigated. Applying elastic foundation under the laminated composite plates has enabled us to achieve desired frequencies. The displacements are based C° – nine plate bending element and each node has three degree of freedom. The equations of motion are derived using Hamilton's principle. Results indicate the tension forces will increase the natural frequency while the compression force reduces the natural frequency. The buckling force of plate is computed by increasing the absolute value of compressive force until the natural frequency tends to zero. Dynamic of moving mass in a circular path on the laminated composite plate is also investigated. Displacement of plate center reveals a sinusoidal pattern in time.
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Zaki, Wael, Xiaojun Gu, Ziad Moumni, and Weihong Zhang. "High-Cycle Fatigue Criterion for Shape Memory Alloys Based on Shakedown Theory." In ASME 2016 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/smasis2016-9165.
Full textAbstract:
Based on a recently developed shakedown theory for non-smooth nonlinear materials, we derive a criterion for high-cycle fatigue in shape memory alloys (SMAs). The fatigue criterion takes into account phase transformation as well as reorientation of martensite variants as the source of fatigue damage. The mathematical derivation of the criterion is based on the requirement of elastic shakedown for a given structure to achieve unlimited fatigue endurance. Elastic shakedown is defined as an asymptotic state in which damage due to time-varying load becomes confined at the mesoscopic scale, or the scale of the grain, with no discernable inelasticity at the macroscopic scale. From an energy standpoint, elastic shakedown corresponds to a situation where energy dissipation becomes bounded and the response elastic after a certain number of loading cycles. A sufficient condition to achieve this state was established by Melan (1936) [1] and Koiter (1960) [2] for elastoplastic materials and later generalized to hardening plasticity by Nguyen (2003) and to non-smooth non-linear materials by Peigney (2014). The latter formulation is applicable to SMAs obeying the ZM constitutive model (Zaki & Moumni, 2007) and is shown here to allow the derivation of a high-cycle fatigue criterion analogous to the one proposed by Dang Van (1973) for elastoplastic materials. The criterion allows establishing a safe domain in stress deviator space at the mesoscopic scale consisting of a hypercylinder with axis parallel to the direction of martensite orientation. The hypercylinder is delimited along its axis by two transverse hyperplanes representing bounds on admissible stress states consistent with the loading conditions for phase transformation. Safety with regard to high-cycle fatigue, upon elastic shakedown, is conditioned by the persistence of the macroscopic stress path, as the load varies and at every material point, strictly within the hypercylinder. The size of the hypercylinder is shown to strongly depend on the relative amount of martensite present in the SMA.
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Zhou, Hong, Kamlesh Borgaonkar, and Govind Raj Venkat Rao. "Five-Bar Double-Slider Two-DOF Parallel Manipulators for Singularity-Free Path Generation." In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-66328.
Full textAbstract:
Parallel manipulators are closed-loop multi-degree-of-freedom linkages, which have the merits of high stiffness, load-bearing, operation speed and precision positioning capabilities that are required in many industrial applications. The main challenges for parallel manipulators are the limited workspace and singularity-free path generation capability. This paper is focused on the singularity-free path generation of five-bar double-slider two-DOF parallel manipulators. The linkage feasibility conditions are derived based on the elimination of dead point position within the workspace. The workspace is generated using the curve-enveloping theory. The singularity characteristics and linkage configurations are presented. The singularity-free path generation capability is analyzed. The performance index contours within the workspace are produced using the condition number of the manipulator Jacobian matrix. This paper shows that five-bar double-slider two-DOF parallel manipulators can be used as effective singularity-free path generators if properly designed. The results of this paper provide a useful map for the proper design of this type of parallel manipulator.
Reports on the topic "Load Path Theory"
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Financial Stability Report - Second Semester of 2020. Banco de la República de Colombia, March 2021. http://dx.doi.org/10.32468/rept-estab-fin.sem2.eng-2020.
Full textAbstract:
The Colombian financial system has not suffered major structural disruptions during these months of deep economic contraction and has continued to carry out its basic functions as usual, thus facilitating the economy's response to extreme conditions. This is the result of the soundness of financial institutions at the beginning of the crisis, which was reflected in high liquidity and capital adequacy indicators as well as in the timely response of various authorities. Banco de la República lowered its policy interest rates 250 points to 1.75%, the lowest level since the creation of the new independent bank in 1991, and provided ample temporary and permanent liquidity in both pesos and foreign currency. The Office of the Financial Superintendent of Colombia, in turn, adopted prudential measures to facilitate changes in the conditions for loans in effect and temporary rules for rating and loan-loss provisions. Finally, the national government expanded the transfers as well as the guaranteed credit programs for the economy. The supply of real credit (i.e. discounting inflation) in the economy is 4% higher today than it was 12 months ago with especially marked growth in the housing (5.6%) and commercial (4.7%) loan portfolios (2.3% in consumer and -0.1% in microloans), but there have been significant changes over time. During the first few months of the quarantine, firms increased their demands for liquidity sharply while consumers reduced theirs. Since then, the growth of credit to firms has tended to slow down, while consumer and housing credit has grown. The financial system has responded satisfactorily to the changes in the respective demands of each group or sector and loans may grow at high rates in 2021 if GDP grows at rates close to 4.6% as the technical staff at the Bank expects; but the forecasts are highly uncertain. After the strict quarantine implemented by authorities in Colombia, the turmoil seen in March and early April, which was evident in the sudden reddening of macroeconomic variables on the risk heatmap in Graph A,[1] and the drop in crude oil and coal prices (note the high volatility registered in market risk for the region on Graph A) the local financial markets stabilized relatively quickly. Banco de la República’s credible and sustained policy response played a decisive role in this stabilization in terms of liquidity provision through a sharp expansion of repo operations (and changes in amounts, terms, counterparties, and eligible instruments), the purchases of public and private debt, and the reduction in bank reserve requirements. In this respect, there is now abundant aggregate liquidity and significant improvements in the liquidity position of investment funds. In this context, the main vulnerability factor for financial stability in the short term is still the high degree of uncertainty surrounding loan quality. First, the future trajectory of the number of people infected and deceased by the virus and the possible need for additional health measures is uncertain. For that reason, there is also uncertainty about the path for economic recovery in the short and medium term. Second, the degree to which the current shock will be reflected in loan quality once the risk materializes in banks’ financial statements is uncertain. For the time being, the credit risk heatmap (Graph B) indicates that non-performing and risky loans have not shown major deterioration, but past experience indicates that periods of sharp economic slowdown eventually tend to coincide with rises in non-performing loans: the calculations included in this report suggest that the impact of the recession on credit quality could be significant in the short term. This is particularly worrying since the profitability of credit establishments has been declining in recent months, and this could affect their ability to provide credit to the real sector of the economy. In order to adopt a forward-looking approach to this vulnerability, this Report presents several stress tests that evaluate the resilience of the liquidity and capital adequacy of credit institutions and investment funds in the event of a hypothetical scenario that seeks to simulate an extreme version of current macroeconomic conditions. The results suggest that even though there could be strong impacts on the credit institutions’ volume of credit and profitability under such scenarios, aggregate indicators of total and core capital adequacy will probably remain at levels that are above the regulatory limits over the horizon of a year. At the same time, the exercises highlight the high capacity of the system's liquidity to face adverse scenarios. In compliance with its constitutional objectives and in coordination with the financial system's security network, Banco de la República will continue to closely monitor the outlook for financial stability at this juncture and will make the decisions that are necessary to ensure the proper functioning of the economy, facilitate the flow of sufficient credit and liquidity resources, and further the smooth operation of the payment systems. Juan José Echavarría Governor