scholarly journals Modeling and simulation of economic processes

Author(s):  
Bogdan Brumar

In general, any activity requires a longer action often characterized by a degree of uncertainty, insecurity, in terms of size of the objective pursued. Because of the complexity of real economic systems, the stochastic dependencies between different variables and parameters considered, not all systems can be adequately represented by a model that can be solved by analytical methods and covering all issues for management decision analysis-economic horizon real. Often in such cases, it is considered that the simulation technique is the only alternative available. Using simulation techniques to study real-world systems often requires a laborious work. Making a simulation experiment is a process that takes place in several stages.

Author(s):  
Cesar Lellis Ferreira Leite ◽  
Guilherme de Aquino Barbosa ◽  
Ma´rio Jorge Lima

Modeling and simulation techniques were used for sizing and management of tank farm facilities. Probabilistic models representing interfaces (market, supply, production, laboratory, etc.) were represented in the model. The technique allows simulation of the logistic costs and service level in different scenarios, subsidizing technical and managerial decisions leading to optimization of inventories. Major advantages are: 1 – once it is created, a model can be used several times to assess the proposed projects and policies; 2 – the analysis methodology used by simulation enables the assessment of a proposed system, even if the entry data are still under form of schemes or drafts; 3 – simulation is generally easier to be applied than analytical methods; A partnership was created among several of Petrobras’ managers for the development of the so-called “Integral and Integrated Model of Transfer and Storage”. Examples of application of such model to some terminals and the relevant results obtained will be shown.


Author(s):  
Lorenzo Damiani ◽  
Pietro Giribone ◽  
Guido Guizzi ◽  
Roberto Revetria ◽  
Elpidio Romano

Simulation is the best tool used to predict the behavior of real world systems. For the analysis of complex systems, simulation is often used prior to the operation of the system as a mediator for a dynamic situation. This chapter presents the issue of complex systems simulation through Discrete Event Simulation (DES) and System Dynamics (SD) techniques. The Authors original approach stands in the combined employ of the two SD and DES simulation techniques to solve real logistic problems. In the course of the chapter, examples of real world issues regarding logistics are explained. In particular, the following case studies are provided: a production environment, a waste collection scheme, a hub base, a harbor including container terminal, bulk terminal and navigation channel.


2019 ◽  
Vol 24 (43) ◽  
pp. 5175-5180 ◽  
Author(s):  
Jatinder Kaur Mukker ◽  
Ravi Shankar Prasad Singh

The properties of nanoparticles can be exploited to overcome challenges in drug delivery. By virtue of its design and size, the pharmacokinetics of nanoparticles are different than other small molecules. Modeling and simulation techniques have great potential to be used in nanoformulation development; however, their use in optimization of nanoformulation is very limited. This review highlights the differences in absorption, distribution, metabolism and excretion (ADME) characteristics of nanoparticles, use of modeling and simulation techniques in nanoformulation development and challenges in the implementation of modeling techniques.


Author(s):  
Ray Huffaker ◽  
Marco Bittelli ◽  
Rodolfo Rosa

Detecting causal interactions among climatic, environmental, and human forces in complex biophysical systems is essential for understanding how these systems function and how public policies can be devised that protect the flow of essential services to biological diversity, agriculture, and other core economic activities. Convergent Cross Mapping (CCM) detects causal networks in real-world systems diagnosed with deterministic, low-dimension, and nonlinear dynamics. If CCM detects correspondence between phase spaces reconstructed from observed time series variables, then the variables are determined to causally interact in the same dynamic system. CCM can give false positives by misconstruing synchronized variables as causally interactive. Extended (delayed) CCM screens for false positives among synchronized variables.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Qing Yao ◽  
Bingsheng Chen ◽  
Tim S. Evans ◽  
Kim Christensen

AbstractWe study the evolution of networks through ‘triplets’—three-node graphlets. We develop a method to compute a transition matrix to describe the evolution of triplets in temporal networks. To identify the importance of higher-order interactions in the evolution of networks, we compare both artificial and real-world data to a model based on pairwise interactions only. The significant differences between the computed matrix and the calculated matrix from the fitted parameters demonstrate that non-pairwise interactions exist for various real-world systems in space and time, such as our data sets. Furthermore, this also reveals that different patterns of higher-order interaction are involved in different real-world situations. To test our approach, we then use these transition matrices as the basis of a link prediction algorithm. We investigate our algorithm’s performance on four temporal networks, comparing our approach against ten other link prediction methods. Our results show that higher-order interactions in both space and time play a crucial role in the evolution of networks as we find our method, along with two other methods based on non-local interactions, give the best overall performance. The results also confirm the concept that the higher-order interaction patterns, i.e., triplet dynamics, can help us understand and predict the evolution of different real-world systems.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ferenc Molnar ◽  
Takashi Nishikawa ◽  
Adilson E. Motter

AbstractBehavioral homogeneity is often critical for the functioning of network systems of interacting entities. In power grids, whose stable operation requires generator frequencies to be synchronized—and thus homogeneous—across the network, previous work suggests that the stability of synchronous states can be improved by making the generators homogeneous. Here, we show that a substantial additional improvement is possible by instead making the generators suitably heterogeneous. We develop a general method for attributing this counterintuitive effect to converse symmetry breaking, a recently established phenomenon in which the system must be asymmetric to maintain a stable symmetric state. These findings constitute the first demonstration of converse symmetry breaking in real-world systems, and our method promises to enable identification of this phenomenon in other networks whose functions rely on behavioral homogeneity.


MRS Bulletin ◽  
2006 ◽  
Vol 31 (5) ◽  
pp. 410-418 ◽  
Author(s):  
Angelo Bongiorno ◽  
Clemens J. Först ◽  
Rajiv K. Kalia ◽  
Ju Li ◽  
Jochen Marschall ◽  
...  

AbstractThe broader context of this discussion, based on a workshop where materials technologists and computational scientists engaged in a dialogue, is an awareness that modeling and simulation techniques and computational capabilities may have matured sufficiently to provide heretofore unavailable insights into the complex microstructural evolution of materials in extreme environments.As an example, this article examines the study of ultrahigh-temperature oxidation-resistant ceramics, through the combination of atomistic simulation and selected experiments.We describe a strategy to investigate oxygen transport through a multi-oxide scale—the protective layer of ultrahigh-temperature ceramic composites ZrB2-SiC and HfB2-SiC—by combining first-principles and atomistic modeling and simulation with selected experiments.


2012 ◽  
Vol 2012 ◽  
pp. 1-24 ◽  
Author(s):  
Mona Riabacke ◽  
Mats Danielson ◽  
Love Ekenberg

Comparatively few of the vast amounts of decision analytical methods suggested have been widely spread in actual practice. Some approaches have nevertheless been more successful in this respect than others. Quantitative decision making has moved from the study of decision theory founded on a single criterion towards decision support for more realistic decision-making situations with multiple, often conflicting, criteria. Furthermore, the identified gap between normative and descriptive theories seems to suggest a shift to more prescriptive approaches. However, when decision analysis applications are used to aid prescriptive decision-making processes, additional demands are put on these applications to adapt to the users and the context. In particular, the issue of weight elicitation is crucial. There are several techniques for deriving criteria weights from preference statements. This is a cognitively demanding task, subject to different biases, and the elicited values can be heavily dependent on the method of assessment. There have been a number of methods suggested for assessing criteria weights, but these methods have properties which impact their applicability in practice. This paper provides a survey of state-of-the-art weight elicitation methods in a prescriptive setting.


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