scholarly journals Оценка производительности причала для целей имитационного моделирования

Author(s):  
A.L. Kuznetsov ◽  
A.V. Galin ◽  
A.D. Semenov ◽  
E.V. Vinogradova

В работе отмечается, что одной из наиболее актуальных задач имитационного моделирования в области морских контейнерных перевозок является взаимодействие между собой контейнерных терминалов одного порта или нескольких портов морского побережья (морского фасада хинтерленда).По этой причине в статье рассматриваются методы оценки производительности причала, основанные на статистических данных и методе Монте-Карло, преимуществом которых является возможность оценить производительность всех операций контейнерного терминала с учетом случайного характера продолжительности отдельных движений путем наблюдения лишь за некоторыми, наиболее часто встречающимися операциями. Эти методы могут использоваться для решения задачи о взаимодействующих терминалах, когда суда осуществляют погрузо-разгрузочные операции на нескольких терминалах порта в рамках одного судозахода. Информация о производительности причала позволяет промоделировать данную систему без учета внутренних процессов контейнерного терминала. В работе доказывается, что существует зависимость между производительностью причала и размером судозахода судна. Корреляционно-регрессионный анализ позволил выявить наиболее подходящие формы зависимости линейную и степенную. В работе также получены оценки разброса выявленных зависимостей для целей имитационного моделирования. Полученная зависимость доказывает адекватность аналитических рассуждений о производительности причала, представленных в предыдущих работах.The paper notes that one of the most important tasks of simulation in the field of container shipping is the interaction of container terminals of one port or several ports of the sea coast (sea front of the hinterland) .For this reason, the article discusses methods for assessing the performance of a berth based on statistical data and Monte Carlo method, the advantage of which is the ability to evaluate the performance of all operations of the container terminal, taking into account the random nature of individual movements by monitoring only for some of the most frequently used operations. These methods can be used to solve the problem of interacting terminals when ships carry out loading and discharging operations at several port terminals within the framework of a single call. Information about the berth productivity allows to simulate this system without taking into account the internal processes of the container terminal. The paper proves that there is a relationship between the berth productivity and the size of the ships call. Correlation-regression analysis revealed the most appropriate forms of dependence - linear and power-law. The paper also obtained estimates of the spread of identified dependencies for the purpose of simulation. The obtained dependence proves the adequacy of analytical reasoning about the performance of the berth presented in previous works.

2020 ◽  
Vol 20 (1) ◽  
pp. 408-420
Author(s):  
Małgorzata Stec

AbstractResearch background: The article attempts to include the accuracy of statistical data in a synthetic evaluation and classification of EU countries in terms of innovation.Purpose: The aim of the article is to evaluate an influence of the accuracy of statistical data on a classification of EU countries in terms of innovation.Research methodology: The research employed diagnostic variables determining the innovation of EU countries and a methodology proposed by the European Commission in the European Innovation Scoreboard 2019. The influence of the uncertainty of the measurement of the diagnostic variables on the Summary Innovation Index of EU countries was evaluated. In order to do this, a procedure employing the Monte Carlo method was proposed.Results: Taking into account the uncertainty of the measurement of variables in the evaluation of the innovation of EU countries resulted in qualifying one of the countries to another innovation group.Novelty: The article draws attention to an important but often neglected problem related to the accuracy of statistical data used in research, and the evaluation of their influence on the calculation of a value of synthetic measure (based on the innovation of EU countries).


2019 ◽  
Vol 114 ◽  
pp. 03003
Author(s):  
D.A. Boyarkin ◽  
D.S. Krupenev ◽  
D.V. Iakubobsky

Modern electricity consumers place increasingly high demands on the level of reliability of power supply and, correspondingly, the reliability of electric power systems (EPS). These requirements should be directly addressed in the EPS development planning tasks. To this end, the evaluation of the level of EPS reliability is performed by employing software and computer systems that have various methods of reliability evaluation implemented therein. Among the variety of methods for identifying reliability indicators to evaluate resource adequacy the most appropriate one is the Monte Carlo method (the method of statistical tests): it enables to perform calculations within a reasonable time with the required accuracy, while the calculation of complex EPS-like systems by means of analytical methods proves impossible because of the large dimensionality of the problem. However, even when using the Monte Carlo method, the difficulties arise as well, namely the problem of the need to reproduce a large number of random states of the simulated EPS and the calculation of the operating mode of each of them. There are several ways to reduce the overall calculation time by either efficient random number generators and optimizers or alternative methods of the calculation of operating modes. The article deals with the issue of bringing up to date the method behind reliability calculation that makes use of the Monte Carlo method. We propose to use regression analysis methods when calculating operating modes of random states of the EPS. To this end, we adopt the support-vector machine and the random forest method. Experimental studies covered in the article attest to the efficiency of the new method, for the 24-node system IEEE RTS-96 the calculation speed has been increased by almost a factor of 4 while maintaining accuracy.


2021 ◽  
Vol 264 ◽  
pp. 05025
Author(s):  
Marufdjan Rasulov ◽  
Masud Masharipov ◽  
Azizbek Ismatullaev

Currently, container shipping plays an important role in international logistics. Terminals handle containers between different modes of transport and are a key element in supply chains. The quality of transport services, in general, depends on the technical and technological parameters of container terminals. At the same time, the task is to optimize the operating mode of the container terminal to reduce logistics costs. This article presents the results of a study of the traffic flows of terminals adjacent to the Tashkent regional railway junction stations, obtained based on timing observations on the unloading of containers arriving at the terminal by road for shipment by container trains. Based on these observations, the regularities of the distribution of the probabilities of the arrival of containers at the terminal and the time of servicing vehicles by a gantry crane were established. With the help of the established patterns, the main indicators were selected that characterize the quality of the container terminal functioning. A mathematical model has been developed and an algorithm for finding the optimal operating mode of a container terminal when forming a container block train. As the results of calculations have shown, the volume of logistics costs for the operation of a container terminal depends on the type and quantity of used handling equipment and the number of supply of fitting wagons to loading and unloading routes.


1974 ◽  
Vol 22 ◽  
pp. 307 ◽  
Author(s):  
Zdenek Sekanina

AbstractIt is suggested that the outbursts of Periodic Comet Schwassmann-Wachmann 1 are triggered by impacts of interplanetary boulders on the surface of the comet’s nucleus. The existence of a cloud of such boulders in interplanetary space was predicted by Harwit (1967). We have used the hypothesis to calculate the characteristics of the outbursts – such as their mean rate, optically important dimensions of ejected debris, expansion velocity of the ejecta, maximum diameter of the expanding cloud before it fades out, and the magnitude of the accompanying orbital impulse – and found them reasonably consistent with observations, if the solid constituent of the comet is assumed in the form of a porous matrix of lowstrength meteoric material. A Monte Carlo method was applied to simulate the distributions of impacts, their directions and impact velocities.


Author(s):  
Makoto Shiojiri ◽  
Toshiyuki Isshiki ◽  
Tetsuya Fudaba ◽  
Yoshihiro Hirota

In hexagonal Se crystal each atom is covalently bound to two others to form an endless spiral chain, and in Sb crystal each atom to three others to form an extended puckered sheet. Such chains and sheets may be regarded as one- and two- dimensional molecules, respectively. In this paper we investigate the structures in amorphous state of these elements and the crystallization.HRTEM and ED images of vacuum-deposited amorphous Se and Sb films were taken with a JEM-200CX electron microscope (Cs=1.2 mm). The structure models of amorphous films were constructed on a computer by Monte Carlo method. Generated atoms were subsequently deposited on a space of 2 nm×2 nm as they fulfiled the binding condition, to form a film 5 nm thick (Fig. 1a-1c). An improvement on a previous computer program has been made as to realize the actual film formation. Radial distribution fuction (RDF) curves, ED intensities and HRTEM images for the constructed structure models were calculated, and compared with the observed ones.


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