scholarly journals Determination of the Most Interconnected Sections of Main Gas Pipelines Using the Maximum Clique Method

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 501
Author(s):  
Sergey Vorobev ◽  
Anton Kolosnitsyn ◽  
Ilya Minarchenko
Keyword(s):  
Flow Problem ◽  
Maximum Clique ◽  
Maximum Flow ◽  
Critical Infrastructures ◽  
Transmission Network ◽  
Gas Pipelines ◽  
Transmission Networks ◽  
Definition Of ◽  
Gas Fields

This article is devoted to the definition of the most important combinations of objects in critical network infrastructures. This study was carried out using the example of the Russian gas transmission network. Since natural gas is widely used in the energy sector, the gas transmission network can be exposed to terrorist threats, and the actions of intruders can be directed at both gas fields and gas pipelines. A defender–attacker model was proposed to simulate attacks. In this model, the defender solves the maximum flow problem to satisfy the needs of gas consumers. By excluding gas pipelines, the attacker tries to minimize the maximum flow in the gas transmission network. Russian and European gas transmission networks are territorially very extensive and have a significant number of mutual intersections and redundant pipelines. Therefore, one of the approaches to inflicting maximum damage on the system is modeled as an attack on a clique. A clique in this study is several interconnected objects. The article presents the list of the most interconnected sections of main gas pipelines, the failure of which can cause the greatest damage to the system in the form of a gas shortage among consumers. Conclusions were drawn about the applicability of the maximum clique method for identifying the most important objects in network critical infrastructures.

scholarly journals The clique approach to identifying critical elements in gas transmission networks

2021 ◽  
Vol 289 ◽  
pp. 03009
Author(s):  
Sergey Vorobev ◽  
Anton Kolosnitsyn ◽  
Ilya Minarchenko
Keyword(s):  
Maximum Flow ◽  
Gas Production ◽  
Transmission Network ◽  
Gas Pipelines ◽  
Potential Threat ◽  
Transmission Networks ◽  
Critical Elements ◽  
System Operator ◽  
Gas Fields ◽  
The Given

We consider the gas transmission network operating on the territory of the Russian Federation. This network includes gas fields, gas consumers, nodal compressor stations, underground gas storages, which, depending on the given scenario of the system operation, can act as gas sources or gas consumers. The nodes are connected by means of gas pipelines. Because natural gas is used in heat and power engineering and electricity, the gas transmission network may be exposed to terrorist threats, and the actions of intruders may be directed both at gas production facilities and gas pipelines. To simulate intruders attacks, a model of the attacker-defender type was proposed. In this model, the defender, represented by the system operator, solves the problem of finding the maximum flow to meet the needs of gas consumers. The attacker, in turn, attempts to minimize the maximum flow in the gas transmission network by excluding either nodes or gas pipelines. Gas transmission networks in Russia and Europe are very extensive, ramified, and have many bridges and reserve gas pipelines. Therefore, to inflict maximum damage to the system, attacks on cliques, that is, on several interconnected objects, are modelled. The article presents the results of test calculations, in which we identify the most significant combinations of objects in the gas transmission network in terms of the potential threat from terrorist attacks.

scholarly journals Combination of the SCS-CN and the GRADEX models to maximum flow estimation

RBRH ◽  
2018 ◽  
Vol 23 (0) ◽  
Author(s):  
Tainá Mota ◽  
Mauro Naghettini ◽  
Wilson Fernandes ◽  
Francisco Silva
Keyword(s):  
Probability Distribution ◽  
Maximum Flow ◽  
Drainage Basins ◽  
Frequency Curve ◽  
Maximum Rainfall ◽  
Flow Estimation ◽  
The Many ◽  
Definition Of ◽  
Scs Cn

ABSTRACT The absence of hydrometric monitoring of adequate extension, periodicity, temporal resolution and quality is the Brazilian reality in many drainage basins. It’s common the use of rainfall-runoff models of simple application to determine rainfall excess volumes, such as the SCS-CN method. Although the SCS method is broadly accepted, many authors have questioned the results derived from its application to catchments with distinct characteristics than those studied during its original formulation. An alternate method for maximum flow estimation in catchments with scarce monitoring is the GRADEX method, which proposes extrapolation of the flood volumes’ frequency curve from precipitation series. Despite being a consolidated method, it is rarely used in Brazil because of the difficulties found in fulfilling its initial hypotheses. This paper suggests, therefore, the combination of both methods, aiming for a methodology that better describes the uncertainties involved in the determination of the direct flood volumes’ probability distribution. The case study is conducted on the Serra Azul river catchment, Juatuba – MG, which offers 12 years of continuous records. The referred combination occurs on the definition of the lower and upper boundaries of the probability distribution of global water retention in the soil and in the catchment, as embedded in the GRADEX method, from the CNASYMPTOTIC concept. The modelled scenarios bear evidence of the many possibilities that may exist in the extrapolation of the frequency curve of surface runoff volumes suggests a range of results that better underpins the definition of the saturation condition and, consequently, the maximum rainfall excess calculation, as compared to the originally proposed methods.

scholarly journals A Review of Flow-Capacitated Networks: Algorithms, Techniques and Applications

2021 ◽  
pp. 1-33
Author(s):  
Omar Mutab Alsalami ◽  
Ali Muhammad Ali Rushdi
Keyword(s):  
Network Flow ◽  
Flow Problem ◽  
Maximum Flow ◽  
Flow Properties ◽  
Transformation Techniques ◽  
Graph Theoretic ◽  
Network Problems ◽  
Definition Of ◽  
Capacitated Network ◽  
Alternative Solutions

This paper presents a review of flow network concepts, including definition of some graph-theoretic basics and a discussion of network flow properties. It also provides an overview of some crucial algorithms used to solve the maximum-flow problem such as the Ford and Fulkerson algorithm (FFA), supplemented with alternative solutions, together with the essential terminology for this algorithm. Moreover, this paper explains the max-flow min-cut theorem in detail, analyzes the concepts behind it, and provides some examples and their solutions to demonstrate this theorem. As a bonus, it expounds the reduction and transformation techniques used in a capacitated network. In addition, this paper reviews one of the popular techniques for analyzing capacitated networks, which is the “decomposition technique”. This technique is centered on conditioning a complicated network on the possible states of a keystone element  or on the possible combinations of states of many keystone elements. Some applications of capacitated network problems are addressed based on each type of problem being discussed.

scholarly journals Playing with the Maximum-Flow Problem

10.29007/tkk1 ◽  
2018 ◽  
Author(s):  
Orna Kupferman
Keyword(s):  
Communication Networks ◽  
Flow Problem ◽  
Optimal Strategies ◽  
Maximum Flow ◽  
Computing Environment ◽  
Open Problems ◽  
Maximum Flow Problem ◽  
Road Systems ◽  
Definition Of ◽  
Special Case

In the traditional maximum-flow problem, the goal is to transfer maximum flow in a network by directing, in each vertex in the network, incoming flow into outgoing edges. The problem has been extensively used in order to optimize the performance of networks in numerous application areas. The definition of the problem corresponds to a setting in which the authority has control on all vertices of the network. Today’s computing environment involves parties that should be considered adversarial. We survey recent studies on flow games, which capture settings in which the vertices of the network are owned by different and selfish entities. We start with the case of two players, max (the authority), which aims at maximizing the flow, and min (the hostile environment), which aims at minimizing the flow. We argue that such flow games capture many modern settings, such as partially- controlled pipe or road systems or hybrid software-defined communication networks. We then continue to the special case where all vertices are owned by min. This case captures evacuation scenarios, where the goal is to maximize the flow that is guaranteed to travel in the most unfortunate routing decisions. Finally, we study the general case, of multiple players, each with her own target vertex. In all settings, we study the problems of finding the maximal flows, optimal strategies for the players, as well as stability and equilibrium inefficiency in the case of multi-player games. We discuss additional variants and their applications, and point to several interesting open problems.

State Failure and the Political Violence Phenomenon: A Comparative Analysis of Iraq and Syria Cases

2016 ◽  
Vol 4 (2) ◽  
pp. 170 ◽  
Author(s):  
K. Eylem Özkaya Lassalle
Keyword(s):  
Cold War ◽  
Political Violence ◽  
State Failure ◽  
The Political ◽  
Collective Violence ◽  
Short Run ◽  
Definition Of ◽  
The Cold War

The concept of failed state came to the fore with the end of the Cold War, the collapse of the USSR and the disintegration of Yugoslavia. Political violence is central in these discussions on the definition of the concept or the determination of its dimensions (indicators). Specifically, the level of political violence, the type of political violence and intensity of political violence has been broached in the literature. An effective classification of political violence can lead us to a better understanding of state failure phenomenon. By using Tilly’s classification of collective violence which is based on extent of coordination among violent actors and salience of short-run damage, the role played by political violence in state failure can be understood clearly. In order to do this, two recent cases, Iraq and Syria will be examined.

DEFINITION OF TIME SPENT ON REPAIR OF BUS TRANSMISSION UNITS TAKING INTO ACCOUNT TECHNOLOGICAL EQUIPMENT RELIABILITY

2020 ◽  
Vol 2020 (9) ◽  
pp. 29-33
Author(s):  
Sergey Bulatov
Keyword(s):  
Negative Impact ◽  
Probabilistic Method ◽  
Technological Equipment ◽  
Quality And Safety ◽  
Transmission Unit ◽  
Equipment Reliability ◽  
Hours Of Work ◽  
Definition Of ◽  
Time Decrease

The paper purpose is the effectiveness estimation in the technological equipment use, taking into account its reliability and productivity for defective transmission units of buses. The problem consists in the determination of time to be spent on repair of bus transmission units taking into account technological equipment reliability. In the paper there is used a probabilistic method for the prediction bus transmission units, and also a method of the dynamics of averages which allow ensuring minimum of costs for units downtime during repair and equipment cost. The need for repair of transmission units (gear box) arises on an average after 650 hours, the average productivity of the bench makes 4.2 bus / hour. The bench fails on the average after 4600 hours of work, the average time of the bench makes 2 hours. In such a way the solution of the problem specified allows analyzing the necessity of time decrease for transmission unit repair to avoid long downtimes of buses in repair areas without negative impact upon high repair quality and safety during the further operation.

Tests of jackhammers (formation of bench techniques)

2020 ◽  
pp. 28-32
Author(s):  
V.S. Vanaev
Keyword(s):  
Impact Energy ◽  
Bench Tests ◽  
Measuring Complex ◽  
Energy Indicators ◽  
Definition Of ◽  
Determination Of Parameters ◽  
Dynamic Indicators

Development of complex determination of parameters of jackhammers at bench tests is studied. The modern support of tests of jackhammers for the purpose of definition of their energy, vibration and noise indicators is considered. Descriptions of the SORP universal bench and UIPU measuring complex are given. Keywords jackhammer, bench, tests, processing object, energy indicators, impact energy, dynamic indicators [email protected]

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