scholarly journals COMPUTING SHORTEST, FASTEST, AND FOREMOST JOURNEYS IN DYNAMIC NETWORKS

2003 ◽  
Vol 14 (02) ◽  
pp. 267-285 ◽  
Author(s):  
B. BUI XUAN ◽  
A. FERREIRA ◽  
A. JARRY

New technologies and the deployment of mobile and nomadic services are driving the emergence of complex communications networks, that have a highly dynamic behavior. This naturally engenders new route-discovery problems under changing conditions over these networks. Unfortunately, the temporal variations in the network topology are hard to be effectively captured in a classical graph model. In this paper, we use and extend a recently proposed graph theoretic model, which helps capture the evolving characteristic of such networks, in order to propose and formally analyze least cost journey (the analog of paths in usual graphs) in a class of dynamic networks, where the changes in the topology can be predicted in advance. Cost measures investigated here are hop count (shortest journeys), arrival date (foremost journeys), and time span (fastest journeys).

2021 ◽  
pp. 1-27
Author(s):  
Tiberiu Dragu ◽  
Yonatan Lupu

Abstract How will advances in digital technology affect the future of human rights and authoritarian rule? Media figures, public intellectuals, and scholars have debated this relationship for decades, with some arguing that new technologies facilitate mobilization against the state and others countering that the same technologies allow authoritarians to strengthen their grip on power. We address this issue by analyzing the first game-theoretic model that accounts for the dual effects of technology within the strategic context of preventive repression. Our game-theoretical analysis suggests that technological developments may not be detrimental to authoritarian control and may, in fact, strengthen authoritarian control by facilitating a wide range of human rights abuses. We show that technological innovation leads to greater levels of abuses to prevent opposition groups from mobilizing and increases the likelihood that authoritarians will succeed in preventing such mobilization. These results have broad implications for the human rights regime, democratization efforts, and the interpretation of recent declines in violent human rights abuses.


2011 ◽  
pp. 581-599
Author(s):  
Robert Gilles ◽  
Tabitha James ◽  
Reza Barkhi ◽  
Dimitrios Diamantaras

Social networks depict complex systems as graph theoretic models. The study of the formation of such systems (or networks) and the subsequent analysis of the network structures are of great interest. For information systems research and its impact on business practice, the ability to model and simulate a system of individuals interacting to achieve a certain socio-economic goal holds much promise for proper design and use of cyber networks. We use case-based decision theory to formulate a customizable model of information gathering in a social network. In this model, the agents in the network have limited awareness of the social network in which they operate and of the fixed, underlying payoff structure. Agents collect payoff information from neighbors within the prevailing social network, and they base their networking decisions on this information. Along with the introduction of the decision theoretic model, we developed software to simulate the formation of such networks in a customizable context to examine how the network structure can be influenced by the parameters that define social relationships. We present computational experiments that illustrate the growth and stability of the simulated social networks ensuing from the proposed model. The model and simulation illustrates how network structure influences agent behavior in a social network and how network structures, agent behavior, and agent decisions influence each other.


2021 ◽  
Vol 42 (1) ◽  
pp. 30-37
Author(s):  
Gopinath Das ◽  
Bidyarthi Dutta ◽  
Anup Kumar Das

The indicator Citation Swing Factor (CSF) has recently been developed to quantitatively measure the diffusion process from h-core zone to h-core excess zone. This paper calculated CSF for Indian physics and astronomy research output appeared in selective Indian journals since 2005 to 2020. The theoretical values of CSF are also calculated on the basis of its fundamental equation and same was compared it with the respective observed values. The average error over entire time span is found 2.26 per cent indicating close proximity between theoretically expected and practically observed values. Besides, three other scientometric indicators are introduced here, viz. Time-Normalised Total Cited Ratio (TC), Time-Normalised Cited Uncited Ratio (CU) and Time-Normalised Total Uncited Ratio (TU). Of these four indicators, the variation of TC is highest (1.76), followed by TU (0.53), CU (0.37) and CSF(E) (0.09), as evident from the values of respective Coefficients of Variations. The numerical values of these indicators are found out for the same sample and the temporal variations along with their mutual interrelationships are determined by regression analysis. It is observed that the three indicators, TC, CU and TU are mutually interrelated through the following linear regression equations, i.e. TC = -0.76 + 1.88*TU and CU = -0.201 + 0.34*TU.


Author(s):  
Tanvir Singh ◽  
V.P. Agrawal

Nanotechnology can create many new nanomaterials and nanodevices with a vast range of applications, such as in medicine, electronics, biomaterials, and energy production, etc. An attempt is made to develop an integrated systems model for the structure of the nanotechnology system in terms of its constituents and interactions between the constituents and processes, etc. using graph theory and matrix algebra. The nanotechnology system is first modeled with the help of graph theory, secondly by variable adjacency matrix and thirdly by multinomial (which is known as a permanent function). The permanent function provides an opportunity to carry out a structural analysis of nanotechnology system in terms of its strength, weakness, improvement, and optimization, by correlating the different systems with its structure. The physical meaning has been associated with each term of the permanent function. Different structural attributes of the nanotechnology system are identified concurrently to reduce cost, time for design and development, and also to develop a graph-theoretic model, matrix model, and multinomial permanent model of nanotechnology system. The top-down approach for a complete analysis of any nanotechnology systems is given. The general methodology is presented for the characterization and comparison of two nanotechnology systems.


Author(s):  
Jian Xie ◽  
Youyi Bi ◽  
Zhenghui Sha ◽  
Mingxian Wang ◽  
Yan Fu ◽  
...  

Abstract Understanding the impact of engineering design on product competitions is imperative for product designers to better address customer needs and develop more competitive products. In this paper, we propose a dynamic network based approach to modeling and analyzing the evolution of product competitions using multi-year product survey data. We adopt Separate Temporal Exponential Random Graph Model (STERGM) as the statistical inference framework because it considers the evolution of dynamic networks as two separate processes: formation and dissolution. This treatment allows designers to investigate why two products enter into competition and why a competitive relationship preserves or dissolves over time. In an open market, the available products to customers are continuously changing over the time, posing challenges for conventional modeling methods concerning fixed product input. Consequently, we propose to leverage “structural zeros” in STERGM to tackle the problem of modeling varying product competitors as nodes in dynamic networks. We use China’s automotive market as a case study to illustrate the implementation of the proposed approach and its benefits compared to the static network modeling approach based on Exponential Random Graph Model (ERGM). The results show that our approach identifies the driving factors associated with product attributes and current market competition structures for the change of competition in both formation and dissolution processes. The insights gained from this paper can help designers better interpret the temporal changes of product competition relations and make product design decisions with the aid of dynamic network-based models.


2011 ◽  
Vol 208 (2) ◽  
pp. 142-152 ◽  
Author(s):  
Jacek Blazewicz ◽  
Edmund K. Burke ◽  
Marta Kasprzak ◽  
Alexandr Kovalev ◽  
Mikhail Y. Kovalyov

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