scholarly journals Immunized Token-Based Approach for Autonomous Deployment of Multiple Mobile Robots in Burnt Area

2021 ◽  
Vol 13 (20) ◽  
pp. 4135
Author(s):  
Sulemana Nantogma ◽  
Weizhi Ran ◽  
Pengfei Liu ◽  
Zhang Yu ◽  
Yang Xu

Collaborative exploration, sensing and communication in previously unknown environments with high network latency, such as outer space, battlefields and disaster hit areas are promising in multi-agent applications. When disasters such as large fires or natural disasters occur, previously established networks might be destroyed or incapacitated. In these cases, multiple autonomous mobile robots (AMR) or autonomous unmanned ground vehicles carrying wireless devices and/or thermal sensors can be deployed to create an end-to-end communication and sensing coverage to support rescue efforts or access the severity of damage. However, a fundamental problem is how to rapidly deploy these mobile agents in such complex and dynamic environments. The uncertainties introduced by the operational environment and wide range of scheduling problem have made solving them as a whole challenging. In this paper, we present an efficient decentralized approach for practical mobile agents deployment in unknown, burnt or disaster hit areas. Specifically, we propose an approach that combines methods from Artificial Immune System (AIS) with special token messages passing for a team of interconnected AMR to decide who, when and how to act during deployment process. A distributed scheme is adopted, where each AMR makes its movement decisions based on its local observation and a special token it receives from its neighbors. Empirical evidence of robustness and effectiveness of the proposed approach is demonstrated through simulation.

2020 ◽  
Vol 35 (2) ◽  
pp. 101-121
Author(s):  
Chava Brownfield-Stein

Examining the activities of the Israel Defense Forces along the Gaza-Israel border, this article identifies a new phase in what the author calls ‘military-police fusion’. The analysis focuses on novel technologies—remote-controlled weapon stations and unmanned ground vehicles—and on the women soldiers who operate these systems. The central claim is that the blurring of boundaries between military and policing missions, combined with high-tech weaponry, has resulted in the development and implementation of new modes of violence that are currently undergoing a process of redefinition and feminization. The article addresses three key dimensions of the processes occurring in the hybrid operational environment along the Gaza-Israel border: the legal dimension, the technological dimension, and the gender dimension.


2021 ◽  
pp. 54-59
Author(s):  
L. R. Yurenkova ◽  
O. A. Yakovuk ◽  
I. V. Morozov

The article provides examples of how the device known as the «angle reflector» a few decades ago has been increasingly used in various fields of science and technology in recent years. Angle reflectors are designed to change (reflect) optical and radar rays in the direction, opposite to the original direction. At present, angle reflectors are widely used to ensure the safety of road transport on dangerous road sections. Radio wave reflectors have the same design as optical ones; therefore, in radio detection and location, angle reflectors are used to send warning signals to ship radars on bridge supports, beacons and buoys. Modern angle reflectors attached to meteorological probes allow determining the direction and speed of the wind at high altitude, which is especially important in the study of the outer space. In recent years, devices have been developed to improve the accuracy of radar stations calibration. The examples of graphical calculation of angle reflectors presented in the article clearly demonstrate the primary role of geometry in the design activity of an engineer. The graphical calculation is based on the theoretical positions of projective geometry. The design and calculation of optical systems is carried out by the graphoanalytic method, since only with a combination of graphical and analytical methods it is possible to accurately calculate the course of a light beam, laser, or radio wave and thereby determine the design parameters of the devices. The article focuses on a graphical method for calculating two types of angle reflectors using orthogonal projection, due to which modern engineers will be able to create more up-to-date designs of optical systems with a wide range of applications.


Author(s):  
Riccardo De Pascalis ◽  
William J. Parnell ◽  
I. David Abrahams ◽  
Tom Shearer ◽  
Donna M. Daly ◽  
...  

For the first time, the problem of the inflation of a nonlinear viscoelastic thick-walled spherical shell is considered. Specifically, the wall has quasilinear viscoelastic constitutive behaviour, which is of fundamental importance in a wide range of applications, particularly in the context of biological systems such as hollow viscera, including the lungs and bladder. Experiments are performed to demonstrate the efficacy of the model in fitting relaxation tests associated with the volumetric inflation of murine bladders . While the associated nonlinear elastic problem of inflation of a balloon has been studied extensively, there is a paucity of studies considering the equivalent nonlinear viscoelastic case. We show that, in contrast to the elastic scenario, the peak pressure associated with the inflation of a neo-Hookean balloon is not independent of the shear modulus of the medium. Moreover, a novel numerical technique is described in order to solve the nonlinear Volterra integral equation in space and time originating from the fundamental problem of inflation and deflation of a thick-walled nonlinear viscoelastic shell under imposed pressure.


2020 ◽  
Vol Vol. 36 (No. 2) ◽  
pp. 71-77
Author(s):  
Katarina Haviernikova ◽  
Janka Betakova

Small and medium-sized enterprises (SMEs) in developed countries represent an important part of their economic environment. They belong to accelerators of economic development in regions and countries. One of the specifications of SMEs is that they allow people to learn to use their own entrepreneurial skills. Thus, the success of SMEs depends on the skills of the person who is responsible for business management in the enterprise. Without skilled and competent managers no activity will be performed effectively. The development and changes in the economic environment, in which SMEs operate, cause the various reversals connected with uncertainty and the resulting risks. A competent person (owner/manager) in SME will need to anticipate these risks and develop appropriate mitigation and strategies for them. The owner/manager of SME should consider the fact, that there could be deviations in the realization process against the planned goal. This deviation presents the risk and the representative of SME should know, how it is possible to manage this risk. It means to reduce its negative impact. The lack of knowledge is a fundamental problem in the failure of most initiatives in the SMEs and the lack of experience can become a major risk to business survival. The goal of owners/managers in SMEs should be to reduce the possible errors and risks in that way that the SME gets into a situation in which it can anticipate changes, and it is able to respond to them and exploit them to their advantage. Each SME is unique and the risk may occur differently in comparison with other SMEs. Risk management and mitigation of risk are important to ensure the security of the company and its continuous development. The risk management in SMEs is perceived as a means of the improvement of SMEs’ success in their activities, due to the fact, that in most cases the unpredictable situations represent a serious loss-making exposure for the SMEs business sector which leads to the loss. For those SMEs whose capital base is insufficient, they can have catastrophic consequences in the case of realized activities, and they can lead to financial losses and subsequently to possible bankruptcy. For this reason, risk management is a prerequisite for minimization of the negative effects of unexpected situations. Still, a lot of SMEs rarely carry out process-related activities risk management. It is affected by limited resources (financial, human), which SMEs have, and which process risk management. There is a wide range of studies focused on risk management in SMEs, but only several of them are focused currently on the responsibility for risk management. This paper contributes to the dissemination of knowledge about the responsibility for risk management in SMEs and provides wider analysis in ways of responsibility for it. To reach the main of the paper, questionnaire surveys among 1018 Slovak SMEs were conducted. We compared the responsibility for risk management in SMEs between two groups of SMEs – technological and tourism from the point of view of sized category, and regional of SMEs. For the evaluation of differences and dependencies among three groups of respondents’ answers, according to their size category, economic branch in which they operate, and regional location, the Chi-square test was used. The associations among respondents’ answers were evaluated through Cramer’s V. The results showed the differences in responsibility for risk management among Slovak SMEs. The results of this study may provide implications for subsequent research focused on responsibility for risk management in the wider context.


2019 ◽  
Vol 20 (3) ◽  
pp. 530-560
Author(s):  
Akif Durdu ◽  
Aydan M. Erkmen ◽  
Alper Yilmaz

Abstract This paper outlines the methodology and experiments associated with the reshaping of human intentions based on robot movements within Human-Robot Interactions (HRIs). Although studies on estimating human intentions are well studied in the literature, reshaping intentions through robot-initiated interactions is a new significant branching in the field of HRI. In this paper, we analyze how estimated human intentions can intentionally change through cooperation with mobile robots in real Human-Robot environments. This paper proposes an intention-reshaping system that includes either the Observable Operator Models (OOMs) or Hidden Markov Models (HMMs) to estimate human intention and decide which moves a robot should perform to reshape previously estimated human intentions into desired ones. At the low level, the system needs to track the locations of all mobile agents using cameras. We test our system on videos taken in a real HRI environment that has been developed as our experimental setup. The results show that OOMs are faster than HMMs and both models give correct decisions for testing sequences.


1989 ◽  
Vol 134 ◽  
pp. 347-348
Author(s):  
Richard A. Shaw ◽  
Michael M. De Robertis

We have obtained high signal-to-noise ratio CCD spectra at ≤ 150 km/s resolution for 6 high-ionization Seyfert galaxies. We analyzed the profiles of the emission-lines over a wide range in both ionization potential (IP) and critical density (Ncr) in order to study the fundamental problem of cloud motion in the narrow-line region (NLR). Using the known correlations between FWHM and IP and/or Ncr for these galaxies, and assuming that the blueward profile asymmetries result from the combined effects of radially infalling or outflowing clouds and extinction within or between them, we deconvolve these effects by analyzing the correlation between emission-line asymmetries and both IP and Ncr. We find fair to good correlations in the sense that lines with high IP and Ncr also tend to have high asymmetry, while lines with low IP and Ncr have low but usually non-zero asymmetry. Simulated emission-line profiles generated with a spherically-symmetric model of a NLR suggest that the extinction arises primarily within radially infalling clouds.


2012 ◽  
Vol 24 (4) ◽  
pp. 677-685
Author(s):  
Kenji Terabayashi ◽  
◽  
Toru Morita ◽  
Hiroya Okamoto ◽  
Kazunori Umeda ◽  
...  

In car driving support systems and mobile robots, it is important to understand three-dimensional environment widely at once. In this paper, we use a fish-eye camera as a sensor to measure three-dimensional (3D) environments. This camera can take a wide-range and distortional image and can be easily mounted on cars. We propose a method for reconstructing 3D environment using fish-eye images based on Epipolar-Plane Image (EPI) analysis. This method enables easy and stable matching of feature points. The effectiveness of the proposed method is verified by experiments.


2014 ◽  
Vol 22 (1) ◽  
pp. 35-45
Author(s):  
Nicholas Maxwell

Purpose – In this paper the author aims to sketch a liberal-studies course designed to explore our fundamental problem of thought and life: How can our human world exist and best flourish embedded as it is in the physical universe? The fundamental character of this problem provides one with the opportunity to explore a wide range of issues. Design/methodology/approach – The paper addresses the following questions: what does physics tell us about the universe and ourselves? How do we account for everything physics leaves out? How can living brains be conscious? If everything occurs in accordance with physical law, what becomes of free will? How does Darwin's theory of evolution contribute to the solution to the fundamental problem? What is the history of thought about this problem? What is of most value associated with human life? What kind of civilized world should we seek to help create? Why is the fundamental problem not a part of standard education in schools and universities? What are the most serious global problems confronting humanity? Can humanity learn to make progress towards as good a world as possible? Findings – Taking the fundamental problem as central provides the course with a coherent structure. The course would be conducted as a seminar, and it would respond to queries and suggestions from students. Research limitations/implications – The paper provides only a sketch of the character of the course. Practical implications – The course would be conducted as a seminar, and it would respond to queries and suggestions from students. Originality/value – Taking the fundamental problem as central provides the course with a coherent structure.


Author(s):  
D. Botto ◽  
M. Lavella ◽  
M. M. Gola

The modelling of the friction interfaces has received much attention in recent years from the aerospace industry. In order to obtain reliable prediction of the nonlinear dynamic behaviour of the disc and blades in the aerospace engine the friction forces at interfaces, such as in under-platform dampers, blade and fir tree roots or shrouds, must be modelled accurately. Two contact parameters, namely the contact stiffness and the coefficient of friction, are sufficient to model, with good accuracy, the friction contact. The contact parameters are obtained experimentally, and are of interest for the designer only if representative of the operational environment of the engine. To pursue this aim a test rig has been designed to perform experiments in a wide range of temperatures, with different combinations of normal and tangential load, frequencies and mating materials, representative of the real operating condition of the engine. Most of the rigs found in literature perform most likely point contact even if the two bodies have plane mating surfaces. The design of a real plane-on-plane contact test rig is not an easy task but despite the difficulty a solution was found in the design shown in this work. The core of the rig is a tilting mechanism enabling one surface to lies down on the other so that the plane-on-plane contact is achieved, at least within the flatness geometrical tolerance of the surfaces. The results of the experiments are the hysteresis loops, namely the tangential contact force against the relative displacement, from which the contact parameters can be calculated. Measurements of displacements are taken very close to the actual contact area and are performed by means of two laser interferometers. Localized heating is achieved by means of an induction heating machine while a thermocouple measures the temperature at points close to the contact area.


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