Dynamic system of indices determining technical equipment of railroad infrastructure

Relationship Of ◽

The Given ◽

Optimum Relationship

Objective: To obtain technical equipment of infrastructure and terminal capacity relations in order to determine the necessary gridiron of tracks, as well as to assess efficiency and optimization of existing stations’ functioning. Methods: Based on synthesis and analysis of stations’ operation, as well as transport systems’ simulation modeling theory. Results: Parameters, influencing the present and designed terminal capacity, were identified. Cause-and-effect relations of events, resulting in railway machinery being brought in non-serviceable condition, are established. Dynamic system of indices was suggested, allowing for a more precise solution of the following tasks: to identify the necessary and sufficient gridiron of tracks for passing the specified amount of traffic, to assess the most probable amount of traffic at the station and its loading. Criteria of input and output flows of traffic at the station, as well as lay-over and trains' delays were stated, the former make it possible to analyze the suggested technical equipment and station functioning. Practical importance: On the basis of obtained relations it is possible to specify optimum relationship of trains’ lay-over time at station yards, the reserve of gridiron of tracks’ elements time in use and the number of routes being implemented at the station, as well as the necessary gridiron of tracks within the given аmount of train traffic. The results of the research may be applied in designing new railway stations, as well as optimization of station functioning and reconstruction of the existing stations.

Mechanochemistry of fluoride solids: from mechanical activation to mechanically stimulated synthesis

ChemTexts ◽

10.1007/s40828-021-00133-2 ◽

2021 ◽

Vol 7 (2) ◽

Author(s):

Gudrun Scholz

Keyword(s):

Mechanical Activation ◽

Mechanochemical Synthesis ◽

Alkaline Earth ◽

Earth Metal ◽

Alkaline Earth Metal ◽

Technical Equipment ◽

Metal Compounds ◽

Potential Applications ◽

The Given ◽

Mechanochemical Reactions

Abstract This lecture text is focused on the comparatively young field of mechanochemistry of fluoride solids, considering both their mechanical activation and their mechanochemical synthesis. Beside a literature survey, the mechanochemical synthesis of binary fluorides MF2, MF3, of complex fluorides MMgF4, of solid solutions MaxMb1−xF2 or M1−xLnxF2+x (Ln: Y, Eu) and of fluorine-containing coordination polymers is presented. Owing to their interesting potential applications in the field of fluoride ion conductivity or luminescence properties when doped, most of the given examples are alkaline earth metal compounds. A short historical survey, remarks on peculiarities and consequences of mechanical activation as well as the necessary technical equipment for mechanochemical reactions precede the section. Graphic abstract

On cryptographic properties of (n + 1)-bit S-boxes constructed by known n-bit S-boxes

Journal of Mathematical Cryptology ◽

10.1515/jmc-2020-0004 ◽

2020 ◽

Vol 15 (1) ◽

pp. 258-265

Author(s):

Yu Zhou ◽

Daoguang Mu ◽

Xinfeng Dong

Keyword(s):

Sufficient Conditions ◽

Sum Of Squares ◽

Basic Component ◽

Necessary And Sufficient Conditions ◽

Autocorrelation Functions ◽

Walsh Spectrum ◽

Cryptographic Algorithms ◽

Relationship Of

AbstractS-box is the basic component of symmetric cryptographic algorithms, and its cryptographic properties play a key role in security of the algorithms. In this paper we give the distributions of Walsh spectrum and the distributions of autocorrelation functions for (n + 1)-bit S-boxes in [12]. We obtain the nonlinearity of (n + 1)-bit S-boxes, and one necessary and sufficient conditions of (n + 1)-bit S-boxes satisfying m-order resilient. Meanwhile, we also give one characterization of (n + 1)-bit S-boxes satisfying t-order propagation criterion. Finally, we give one relationship of the sum-of-squares indicators between an n-bit S-box S0 and the (n + 1)-bit S-box S (which is constructed by S0).

Bipartite graphs with close domination and k-domination numbers

Open Mathematics ◽

10.1515/math-2020-0047 ◽

2020 ◽

Vol 18 (1) ◽

pp. 873-885

Author(s):

Gülnaz Boruzanlı Ekinci ◽

Csilla Bujtás

Keyword(s):

Positive Integer ◽

Dominating Set ◽

Domination Number ◽

Bipartite Graphs ◽

Sufficient Condition ◽

Necessary And Sufficient Condition ◽

Minimum Cardinality ◽

Vertex Set ◽

Abstract Let k be a positive integer and let G be a graph with vertex set V(G) . A subset D\subseteq V(G) is a k -dominating set if every vertex outside D is adjacent to at least k vertices in D . The k -domination number {\gamma }_{k}(G) is the minimum cardinality of a k -dominating set in G . For any graph G , we know that {\gamma }_{k}(G)\ge \gamma (G)+k-2 where \text{Δ}(G)\ge k\ge 2 and this bound is sharp for every k\ge 2 . In this paper, we characterize bipartite graphs satisfying the equality for k\ge 3 and present a necessary and sufficient condition for a bipartite graph to satisfy the equality hereditarily when k=3 . We also prove that the problem of deciding whether a graph satisfies the given equality is NP-hard in general.

A General Analysis of Sequential Social Learning

Mathematics of Operations Research ◽

10.1287/moor.2020.1093 ◽

2021 ◽

Author(s):

Itai Arieli ◽

Manuel Mueller-Frank

Keyword(s):

Social Learning ◽

Utility Function ◽

Posterior Probability ◽

General Analysis ◽

Sufficient Condition ◽

Important Class ◽

General Utility ◽

Learning Game ◽

This paper analyzes a sequential social learning game with a general utility function, state, and action space. We show that asymptotic learning holds for every utility function if and only if signals are totally unbounded, that is, the support of the private posterior probability of every event contains both zero and one. For the case of finitely many actions, we provide a sufficient condition for asymptotic learning depending on the given utility function. Finally, we establish that for the important class of simple utility functions with finitely many actions and states, pairwise unbounded signals, which generally are a strictly weaker notion than unbounded signals, are necessary and sufficient for asymptotic learning.

Technical regulation for the values of hydraulic parameters of used metal pipes in order to extend the period of their use

Proceedings of Petersburg Transport University ◽

10.20295/1815-588x-2021-3-421-427 ◽

2021 ◽

Vol 18 (3) ◽

pp. 421-427

Author(s):

Oleg A. PRODOUS ◽

◽

Lev D. TEREKHOV ◽

Petr P. YAKUBCHIK ◽

Alexander S. CHERNIKH ◽

...

Keyword(s):

Practical Importance ◽

Hydraulic Calculation ◽

Technical Regulation ◽

Supply Networks ◽

Steel Pipes ◽

Head Losses ◽

Metal Pipes ◽

Inner Diameter ◽

Pumping Equipment ◽

Objective: To compare the characteristics of hydraulic potential in worn steel pipes with internal deposits subjected to cleaning by mechanical and chemical methods. Methods: Calculated dependencies are used for hydraulic calculation of new metal pipes and pipes with internal deposits. Results: A calculated dependence was obtained to determine the value of the inner diameter of pipes with any thickness of the layer of internal deposits. The concept of an efﬁcient pipeline is introduced and a comparison made of the values of head losses in new pipes and in pipes with internal deposits. A speciﬁc practical example is considered. For the given example, compare the values of energy consumption of pumping equipment for two methods of cleaning the inner surface of pipes. Measures are indicated to ensure the efﬁciency of operation of water supply networks. Practical importance: It is shown that the chemical method of technical regulation of the hydraulic characteristics of new steel pipes provides an extension of the period of their further use.

Time Coordination of Periodic Passenger Train Connections in Conditions of Single-Track Lines

Mathematical Problems in Engineering ◽

10.1155/2021/3876561 ◽

2021 ◽

Vol 2021 ◽

pp. 1-17

Author(s):

Filip Lorenz ◽

Vit Janos ◽

Dusan Teichmann ◽

Michal Dorda

Keyword(s):

Mathematical Model ◽

Mathematical Programming ◽

Real Data ◽

Real Problem ◽

Single Track ◽

Railway Stations ◽

Optimization Software ◽

Proposed Model ◽

The Individual ◽

The article addresses creation of a mathematical model for a real problem regarding time coordination of periodic train connections operated on single-track lines. The individual train connections are dispatched with a predefined tact, and their arrivals at and departures to predefined railway stations (transfer nodes) need to be coordinated one another. In addition, because the train connections are operated on single-track lines, trains that pass each other in a predefined railway stations must be also coordinated. To optimize the process, mathematical programming methods are used. The presented article includes a mathematical model of the given task, and the proposed model is tested with real data. The calculation experiments were implemented using optimization software Xpress-IVE.

Deontic Relationship in the Context of Jan Woleński’s Metaethical Naturalism

Studia Humana ◽

10.2478/sh-2020-0031 ◽

2020 ◽

Vol 9 (3-4) ◽

pp. 120-130

Author(s):

Tomasz Jarmużek ◽

Mateusz Klonowski ◽

Rafał Palczewski

Keyword(s):

Deontic Logic ◽

Possible Worlds ◽

Normative System ◽

System A ◽

Relationship Of ◽

AbstractIn this paper, we indicate how Jan Woleński’s non-linguistic concept of the norm allows us to clarify the deontic relationship between sentences and the given normative system. A relationship of this kind constitutes a component of the metalogic of relating deontic logic, which subjects the logical value of the deontic sentence to the logical value of the constituent sentence and its relationship with a given normative system in the accessible possible worlds.

Research Anthology on Strategies for Using Social Media as a Service and Tool in Business ◽

Investigating the Impact of Social Media on Gen Y Employees' Engagement

10.4018/978-1-7998-9020-1.ch059 ◽

2021 ◽

pp. 1180-1202

Author(s):

Mohammad Faraz Naim ◽

Usha Lenka

Keyword(s):

Social Media ◽

Employee Engagement ◽

Structural Equation ◽

Equation Modeling ◽

It Industry ◽

Gen Y ◽

Relationship Of ◽

Hr Strategy ◽

The Impact ◽

The study examines the influence of social media on Gen Y employees' engagement. Hypotheses are developed to explain the influence of social media on Gen Y employees' engagement. A sample of 256 Indian Gen Y employees from IT industry participated in the survey. Structural equation modeling is used to test the research hypotheses. Findings reveal that social media has a significant positive effect on Gen Y employees' engagement. It is revealed that social media moderates the relationship of HR practices (communication, collaboration; knowledge sharing and recognition) and engagement in Gen Y employees. While the scope of this study is limited to IT industry and results may not generalize to different industries in different regions. Hence, future studies should test the given hypotheses in different industries of different regions. The findings suggest that organizations should incorporate social media into their HR strategy. The study is one of the first to date, to empirically test the effect of social media on Gen Y employee engagement.

On Cauchy’s Interlacing Theorem and the Stability of a Class of Linear Discrete Aggregation Models Under Eventual Linear Output Feedback Controls

Symmetry ◽

10.3390/sym11050712 ◽

2019 ◽

Vol 11 (5) ◽

pp. 712 ◽

Cited By ~ 2

Author(s):

Manuel De la Sen

Keyword(s):

Dynamic System ◽

Output Feedback ◽

Iteration Step ◽

Stability And Convergence ◽

Feedback Controls ◽

Time Aggregation ◽

The Stability ◽

The Given ◽

Stability Results

This paper links the celebrated Cauchy’s interlacing theorem of eigenvalues for partitioned updated sequences of Hermitian matrices with stability and convergence problems and results of related sequences of matrices. The results are also applied to sequences of factorizations of semidefinite matrices with their complex conjugates ones to obtain sufficiency-type stability results for the factors in those factorizations. Some extensions are given for parallel characterizations of convergent sequences of matrices. In both cases, the updated information has a Hermitian structure, in particular, a symmetric structure occurs if the involved vector and matrices are complex. These results rely on the relation of stable matrices and convergent matrices (those ones being intuitively stable in a discrete context). An epidemic model involving a clustering structure is discussed in light of the given results. Finally, an application is given for a discrete-time aggregation dynamic system where an aggregated subsystem is incorporated into the whole system at each iteration step. The whole aggregation system and the sequence of aggregated subsystems are assumed to be controlled via linear-output feedback. The characterization of the aggregation dynamic system linked to the updating dynamics through the iteration procedure implies that such a system is, generally, time-varying.

Anomalous diffusion of random walk on random planar maps

Probability Theory and Related Fields ◽

10.1007/s00440-020-00986-7 ◽

2020 ◽

Vol 178 (1-2) ◽

pp. 567-611

Author(s):

Ewain Gwynne ◽

Tom Hutchcroft

Keyword(s):

Random Walk ◽

Universality Class ◽

Simple Random Walk ◽

Growth Exponent ◽

Graph Distance ◽

Link Type ◽

Random Planar Map ◽

Planar Maps ◽

Relationship Of ◽

Abstract We prove that the simple random walk on the uniform infinite planar triangulation (UIPT) typically travels graph distance at most $$n^{1/4 + o_n(1)}$$ n 1 / 4 + o n ( 1 ) in n units of time. Together with the complementary lower bound proven by Gwynne and Miller (2017) this shows that the typical graph distance displacement of the walk after n steps is $$n^{1/4 + o_n(1)}$$ n 1 / 4 + o n ( 1 ) , as conjectured by Benjamini and Curien (Geom Funct Anal 2(2):501–531, 2013. arXiv:1202.5454). More generally, we show that the simple random walks on a certain family of random planar maps in the $$\gamma $$ γ -Liouville quantum gravity (LQG) universality class for $$\gamma \in (0,2)$$ γ ∈ ( 0 , 2 ) —including spanning tree-weighted maps, bipolar-oriented maps, and mated-CRT maps—typically travels graph distance $$n^{1/d_\gamma + o_n(1)}$$ n 1 / d γ + o n ( 1 ) in n units of time, where $$d_\gamma $$ d γ is the growth exponent for the volume of a metric ball on the map, which was shown to exist and depend only on $$\gamma $$ γ by Ding and Gwynne (Commun Math Phys 374:1877–1934, 2018. arXiv:1807.01072). Since $$d_\gamma > 2$$ d γ > 2 , this shows that the simple random walk on each of these maps is subdiffusive. Our proofs are based on an embedding of the random planar maps under consideration into $${\mathbb {C}}$$ C wherein graph distance balls can be compared to Euclidean balls modulo subpolynomial errors. This embedding arises from a coupling of the given random planar map with a mated-CRT map together with the relationship of the latter map to SLE-decorated LQG.