scholarly journals The Role of Visibility in Pursuit/Evasion Games

2021 ◽  
Author(s):  
Athanasios Kehagias ◽  
Dieter Mitsche ◽  
Paweł Prałat
Keyword(s):  
Random Walk ◽  
Mobile Robotics ◽  
Quantitative Measure ◽  
Point Of View ◽  
Pursuit Evasion ◽  
The Cost ◽  
Theoretical Results ◽  
Discretized Model ◽  
Cops And Robber

The cops-and-robber (CR) game has been used in mobile robotics as a discretized model (played on a graph G) of pursuit/evasion problems. The “classic” CR version is a perfect information game: the cops’ (pursuer’s) location is always known to the robber (evader) and vice versa. Many variants of the classic game can be defined: the robber can be invisible and also the robber can be either adversarial (tries to avoid capture) or drunk (performs a random walk). Furthermore, the cops and robber can reside in either nodes or edges of G. Several of these variants are relevant as models or robotic pursuit/evasion. In this paper, we first define carefully several of the variants mentioned above and related quantities such as the cop number and the capture time. Then we introduce and study the cost of visibility (COV), a quantitative measure of the increase in difficulty (from the cops’ point of view) when the robber is invisible. In addition to our theoretical results, we present algorithms which can be used to compute capture times and COV of graphs which are analytically intractable. Finally, we present the results of applying these algorithms to the numerical computation of COV.

scholarly journals The Role of Visibility in Pursuit/Evasion Games

2021 ◽  
Author(s):  
Athanasios Kehagias ◽  
Dieter Mitsche ◽  
Paweł Prałat
Keyword(s):  
Random Walk ◽  
Mobile Robotics ◽  
Quantitative Measure ◽  
Point Of View ◽  
Pursuit Evasion ◽  
The Cost ◽  
Theoretical Results ◽  
Discretized Model ◽  
Cops And Robber

The cops-and-robber (CR) game has been used in mobile robotics as a discretized model (played on a graph G) of pursuit/evasion problems. The “classic” CR version is a perfect information game: the cops’ (pursuer’s) location is always known to the robber (evader) and vice versa. Many variants of the classic game can be defined: the robber can be invisible and also the robber can be either adversarial (tries to avoid capture) or drunk (performs a random walk). Furthermore, the cops and robber can reside in either nodes or edges of G. Several of these variants are relevant as models or robotic pursuit/evasion. In this paper, we first define carefully several of the variants mentioned above and related quantities such as the cop number and the capture time. Then we introduce and study the cost of visibility (COV), a quantitative measure of the increase in difficulty (from the cops’ point of view) when the robber is invisible. In addition to our theoretical results, we present algorithms which can be used to compute capture times and COV of graphs which are analytically intractable. Finally, we present the results of applying these algorithms to the numerical computation of COV.

The Role of Polyculture in Sustainable Agricultural Development and Prevention of Land Degradation

2022 ◽  
pp. 132-153
Author(s):  
Milan Marković ◽  
Ivana Marjanović
Keyword(s):  
Land Degradation ◽  
Organic Agriculture ◽  
Agricultural Development ◽  
Point Of View ◽  
Economic Viability ◽  
The Cost ◽  
Sufficient Food ◽  
Growing Population ◽  
Research Show

The aim of the chapter is to show the possible impact of policulture farming on some determinants of sustainable agricultural development, especially from the point of view of economic viability, biodiversity, and land degradation. Increasing the area under polyculture is one of the main solutions to the present environmental problems. The key constraints are economic pressures due to the question of the cost-effectiveness of such a mode of production and the need to provide sufficient food for a growing population, especially in developing countries. The results of the research show that policulture (organic agriculture) should be favored, while monoculture farming must be adequately directed and put in the function of achieving ecological goals of sustainable development as much as possible. In addition, on the example of European countries, it was assessed that there are good conditions for further “greening” of agriculture, bearing in mind the movement of the analyzed indicators.

scholarly journals The Influence of Carbon Tax on the Feasibility of Industrial Project: A Case Study of Heat Exchanger Replacement at PT Kaltim Methanol Industri, Indonesia

2020 ◽  
Vol 20 (2) ◽  
pp. 196
Author(s):  
Wingo Wira Dewanatan ◽  
Muhammad Kurniawan Adiputra ◽  
Imam Karfendi Putro ◽  
Soni Hartanto ◽  
Jonas Kristanto ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Co2 Emission ◽  
Carbon Tax ◽  
Point Of View ◽  
Financial Policies ◽  
Positive Role ◽  
Industrial Project ◽  
The Cost

Petrochemical industries have faced growing pressure to decrease their carbon emission from direct and indirect sources. This work aims to demonstrate a carbon tax’s introduction to a feasibility study on the heat exchanger (HE) replacement project at PT Kaltim Methanol Industri, Indonesia. The project was aimed to avoid methanol release as much as 48.88 MT/year. The release of methanol can also be associated with CO2 emission with an emission factor of 0.6 ton CO2e/ton methanol. Here, we investigated the influence of inclusion and exclusion of carbon tax to monetize the CO2 release. From the project investment point of view, carbon tax inclusion is expected to increase the cost-saving. Introduction of the carbon tax as high as 10 USD/ton CO2e with 5% annual increase gives IRR value of 7.06% with Payout Time (PoT) of ca. 11 years. The IRR value without carbon tax scenario is 6.68 % with the same range of PoT. Hence, the inclusion of carbon tax may increase the feasibility of the project. This work has demonstrated the positive role of the carbon tax to increase the feasibility of a project which inlines with the national initiatives to curb the CO2 emission from chemical industries. It is also worth noting that introduction of carbon tax should be accompanied by a reorganization of government incentives, including several financial policies to create a conducive atmosphere for investors in Indonesia.

scholarly journals Modeling and optimization of hourglass-shaped aquaporins

2018 ◽  
Vol 28 (08) ◽  
pp. 1529-1564
Author(s):  
Matthieu Bonnivard ◽  
Florian Omnès ◽  
Yannick Privat
Keyword(s):  
Chem Phys ◽  
Point Of View ◽  
Optimal Shapes ◽  
Regularity Properties ◽  
Good Filtration ◽  
Single File Transport ◽  
Energy Dissipated ◽  
The Cost ◽  
Filtration Properties

This paper is concerned with aquaporins (AQPs), that are proteins playing the role of water-selective channels also called nanopores, involved in many biological systems. From a technological point of view, it is relevant to design systems enjoying as good filtration properties. Inspired by [S. Gravelle, L. Joly, C. Ybert and L. Bocquet, Large permeabilities of hourglass nanopores: From hydrodynamics to single file transport, J. Chem. Phys. 141 (2014) 18C526], we investigate in a quite general framework shape optimization issues related to the improvement of hourglass-shaped aquaporins performances, in terms of energy dissipated by the fluid through the channel. After modeling this problem mathematically, we show that it is well-posed in some sense, and compute the so-called shape derivative of the cost functional in view of numerical simulations. Noting that our framework requires regularity properties of the free boundary, we introduce a dedicated numerical method, using in particular a proper shape gradient extension-regularization to adapt the mesh at each iteration, in an adequate way. Optimal shapes of aquaporins are then provided for relevant values of parameters, and we finally discuss the observed performances with respect to the existing results/literature.

scholarly journals Properties of Fourier Syntheses and New Syntheses

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 538
Author(s):  
Maria Cristina Burla ◽  
Benedetta Carrozzini ◽  
Giovanni Luca Cascarano ◽  
Carmelo Giacovazzo ◽  
Giampiero Polidori
Keyword(s):  
Structural Model ◽  
Point Of View ◽  
Special Role ◽  
Fourier Synthesis ◽  
Practical Applications ◽  
Phase Extension ◽  
Points Of View ◽  
Theoretical Results

In this study, the properties of observed, difference, and hybrid syntheses (hybrid indicates a combination of observed and difference syntheses) are investigated from two points of view. The first has a statistical nature and aims to estimate the amplitudes of peaks corresponding to the model atoms, belonging or not belonging to the target structure; the amplitudes of peaks related to the target atoms, missed or shared with the model; and finally, the quality of the background. The latter point deals with the practical features of Fourier syntheses, the special role of weighted syntheses, and their usefulness in practical applications. It is shown how the properties of the various syntheses may vary according to the available structural model and, in particular, how weighted hybrid syntheses may act like an observed and difference or a full hybrid synthesis. The theoretical results obtained in this paper suggest new Fourier syntheses using novel Fourier coefficients: their main features are first discussed from a mathematical point of view. Extended experimental applications show that they meet the basic mission of the Fourier syntheses, enhancing peaks corresponding to the missed target atoms, depleting peaks corresponding to the model atoms not belonging to the target, and significantly reducing the background. A comparison with the results obtained via the most popular modern Fourier syntheses is made, suggesting a role for the new syntheses in modern procedures for phase extension and refinement. The most promising new Fourier synthesis has been implemented in the current version of SIR2014.

Visual and Acoustic Display in Uca Mordax and U. Burgersi, Sibling Species of Neotropical Fiddler Crabs. I. Waving Display

Behaviour ◽  
1983 ◽  
Vol 83 (3-4) ◽  
pp. 229-250 ◽  
Author(s):  
Heinrich-Otto Von Hagen
Keyword(s):  
Point Of View ◽  
Fiddler Crabs ◽  
Interspecific Differences ◽  
Waving Display ◽  
The Mean ◽  
The Cost ◽  
Major Cheliped ◽  
Evolutionary Point ◽  
Analysis Of Motion

AbstractThe fiddler crabs Uca mordax and U. burgersi, living sympatrically from Guatemala to southern Brazil, were until recently discussed as belonging to only one species, because their similarities refer not only to morphology but also to their waving displays, which were called "indistinguishable". A frame-by-frame analysis of motion pictures taken in Trinidad (W.I.) confirmed the presence of many similarities in respect to the special "jerking" type of waving display, the mean duration of routine waves, the effect of increasing excitation, the pattern of leg-waving and the presence of a "precursory" downstroke" of the major cheliped. However, a closer analysis of certain components or elements of the display yielded various interspecific differences. In burgersi there is the tendency to omit the precursory downstroke and to extend all motion components at the cost of all kinds of pauses, while in mordax the contrary is true. Furthermore, the movements of the minor cheliped show a different pattern in the two species. The differences found are discussed in respect to differences in the allometry of the major cheliped and from an evolutionary point of view. It is concluded that the waving display of mordax represents the more ancestral type. The role of the waving display as a possible means of reproductive isolation will be discussed in part II of this study dealing with the acoustic display.

Magnetoviscosity of Colloidal Suspensions

1973 ◽  
Vol 51 (2) ◽  
pp. 180-194 ◽  
Author(s):  
A. C. Levi ◽  
R. F. Hobson ◽  
F. R. McCourt
Keyword(s):  
Reasonable Agreement ◽  
Colloidal Suspension ◽  
Planck Equation ◽  
Colloidal Suspensions ◽  
Theoretical Explanation ◽  
Theoretical Description ◽  
Point Of View ◽  
Theoretical Results ◽  
Ferromagnetic Particles

A theoretical description of the effect of an applied magnetic field on the viscosity of a colloidal suspension of single-domain ferromagnetic particles is given from the point of view of linearized hydrodynamics, starting from a microscopic Fokker–Planck equation. Reasonable agreement is found between theoretical results and previous experimental measurements of the effect. A comparison with an earlier theoretical explanation of the effect is given. It is found, in particular, that a consideration of the role of Brownian motion is not only desirable but crucial to a proper explanation of the magnetoviscosity effect.

Paradoxes of Control: The (Electronic) Monitoring and Reporting System of the Dutch High Speed Alliance (HSA)

2007 ◽  
Vol 38 (2) ◽  
pp. 75-83 ◽  
Author(s):  
Kees Boersma ◽  
Sytze F. Kingma ◽  
Marcel Veenswijk
Keyword(s):  
High Speed ◽  
Electronic Monitoring ◽  
Reporting System ◽  
Point Of View ◽  
Political Agenda ◽  
Technical Problems ◽  
Control Versus ◽  
The Cost ◽  
And Control

Recently, some the large public (transport) infrastructures became an important issue on the Dutch political agenda. It was especially the High Speed Alliance (HSA), one of the major transport infra-structural projects in the Netherlands that attracted a lot of attention. On one hand, this project was highly advanced from a technical point of view; on the other hand, the HSA was characterized by enormous (budgetary, time, and technical) problems. A large part of these problems was supposed to be covered by a complex (electronic) monitoring and reporting system. The system, which was established to exclude uncertainty and risk, created its own uncertainty. In this paper, the authors examine the role of this system in the process of rationalization and control within the HSA-organization by focusing upon the process of sensemaking. The authors argue that the problems within the HSA can best be understood in terms of a paradox: rationalization and control versus local, individual freedom and initiatives. Three major paradoxes have been distinguished: the cost paradox, the control paradox, and the risk paradox.

scholarly journals Interest-Seeking as Sense-Making: Ideas and Business Interests in the New Deal

2011 ◽  
Vol 52 (2) ◽  
pp. 277-311 ◽  
Author(s):  
Sascha Münnich
Keyword(s):  
Welfare State ◽  
New Deal ◽  
Point Of View ◽  
Public Works ◽  
Business Interests ◽  
Supportive Role ◽  
Social Security Act ◽  
The Cost ◽  
The New Deal

AbstractThis article addresses the question of how ideas and interests can be linked in policy analysis. The juxtaposition of the two concepts is criticized from a sociological point of view. Instead, ideas are a substantial element of interest formation. Cognitive and normative worldviews shape the transformation of objective socio-economic positions into subjective, situational action orientations. Interests can be traced back to the interplay between structural positions, situational problems and their idea-based interpretation.It is then shown how these conceptual arguments can bring forward a prominent debate in welfare state analysis: the role of business in the emergence of the American welfare state in the New Deal. While struggling with the question whether the supportive role of some business leaders in theSocial Security Actof 1935 reveals substantial interest changes or strategical adaption, both sides of the debate suffer from an objectivist concept of interest. This one-sided concept of interest comes at the cost of leaving open the question of why business interests changed in the direction of unemployment insurance and not in the direction of other feasible institutional options such as price regulation or public works. These options would also have provided a solution to the problem American employers were facing. Analysis of social reform discourses between 1911 and 1935 shows that the partial reorientation of business people cannot be sufficiently explained without taking into account the growing legitimacy of liberal- corporatist ideas among employers in the 1920s.

Elucidation of block boundaries as the dissolution channels in hydrated cement

1978 ◽  
Vol 36 (1) ◽  
pp. 484-485
Author(s):  
N.V. Belov ◽  
U.I. Papiashwili ◽  
B.E. Yudovich
Keyword(s):  
Liquid Phase ◽  
Grain Boundaries ◽  
Benzoyl Peroxide ◽  
Phase Contrast ◽  
Active Role ◽  
Point Of View ◽  
Hardened Cement ◽  
Hydrated Cement ◽  
Hardened Cement Paste

It has been almost universally adopted that dissolution of solids proceeds with development of uniform, continuous frontiers of reaction.However this point of view is doubtful / 1 /. E.g. we have proved the active role of the block (grain) boundaries in the main phases of cement, these boundaries being the areas of hydrate phases' nucleation / 2 /. It has brought to the supposition that the dissolution frontier of cement particles in water is discrete. It seems also probable that the dissolution proceeds through the channels, which serve both for the liquid phase movement and for the drainage of the incongruant solution products. These channels can be appeared along the block boundaries.In order to demonsrate it, we have offered the method of phase-contrast impregnation of the hardened cement paste with the solution of methyl metacrylahe and benzoyl peroxide. The viscosity of this solution is equal to that of water.

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