When physical communication network infrastructures fail, infrastructure-less communication networks such as mobile ad-hoc networks (MANET), can provide an alternative. This, however, requires MANETs to be adaptable to dynamic contexts characterized by the changing density and mobility of devices and availability of energy sources. To address this challenge, this paper proposes a decentralized context-adaptive topology control protocol. The protocol consists of three algorithms and uses preferential attachment based on the energy availability of devices to form a loop-free scale-free adaptive topology for an ad-hoc communication network. The proposed protocol has a number of advantages. First, it is adaptive to the environment, hence applicable in scenarios where the number of participating mobile devices and their availability of energy resources is always changing. Second, it is energy-efficient through changes in the topology. This means it can be flexibly combined with different routing protocols. Third, the protocol requires no changes on the hardware level. This means it can be implemented on all current phones, without any recalls or investments in hardware changes. The evaluation of the protocol in a simulated environment confirms the feasibility of creating and maintaining a self-adaptive ad-hoc communication network, consisting of multitudes of mobile devices for reliable communication in a dynamic context.
Complex adaptive systems provide a significant number of concepts such as reaction, interaction, adaptation, and evolution. In general, these concepts are modelled employing different techniques which give an inexplicit vision on the system. Therefore, all concepts must be carefully modelled using the same approach to avoid contradiction and guarantee system homogeneity and correctness. However, developing a computing system that includes all these concepts using the same approach is not an easy task and requires a perfect understanding of the system's behaviour. In this paper, we contribute as stepwise towards proposing an approach to model the most important concepts of complex adaptive systems while ensuring homogeneity and the correctness of models. For this aim, we present five standard agent-based models formalizing agent properties, reaction, interaction, adaptation, and evolution. These models are adapted to all cases of complex adaptive systems since they include an abstract description of these concepts. To implement our approach formally, we choose the Event-B method due to the strong assurance of bugs' absence that it guarantees. Besides, it supports horizontal and vertical refinement which facilitates the specification process. Furthermore, the approach of this paper addresses the very abstract level of modelling which expand the use of this approach to other formal methods and tools.
One of the basic approaches in science views behavioral products as a process within a dynamic system. The mechanism might be seen as a representation of many instances of centralized control in real time. Many real systems, however, exhibit autonomy by denying statically treated mechanisms. This study addresses the issues related to the identification of dynamic systems and suggests how determining the basic principles of a collective structure may be the key to understanding complex behavioral processes. A fundamental model is derived to assess the advantages of this perspective using a basic methodology. The connection between perspective and technique demonstrates certain aspects within their actual context while also clearly including the framework of actual dynamic system identification.
Understanding how innovations are accepted in a dynamic and complex market environment is a crucial factor for competitive advantage. To understand the relevant factors for this diffusion and to predict success, empirically grounded agent-based models have become increasingly popular in recent years. Despite the popularity of these innovation diffusion models, no common framework that integrates their diversity exists. This article presents a flexible, modular and extensible common description and implementation framework that allows to depict the large variety of model components found in existing models. The framework aims to provide a theoretically grounded description and implementation framework for empirically grounded agent-based models of innovation diffusion. It identifies 30 component requirements to conceptualize an integrated formal framework description. Based on this formal description, a java-based implementation allowing for flexible configuration of existing and future models of innovation diffusion is developed. As a variable decision support tool in decision-making processes on the adoption of innovations the framework is valuable for the investigation of a range of research questions on innovation diffusion, business model evaluation and infrastructure transformation.
Book detailsGreg Conradi SmithWilliam & Mary, Williamsburg, VACellular Biophysics and Modeling: A Primer on the Computational Biology of Excitable CellsCambridge University Press 2019© Greg Conradi Smith 2019DOI: 10.1017/9780511793905ISBN 978-1-107-00536-5 HardbackISBN 978-0-521-18305-5 Paperback
The concept of false data injection attack (FDIA) was introduced originally in the smart grid domain. While the term sounds common, it specifically means the case when an attacker compromises sensor readings in such tricky way that undetected errors are introduced into calculations of state variables and values. Due to the rapid growth of the Internet and associated complex adaptive systems, cyber attackers are interested in exploiting similar attacks in other application domains such as healthcare, finance, defense, governance, etc. In today’s increasingly perilous cyber world of complex adaptive systems, FDIA has become one of the top-priority issues to deal with. It is a necessity today for greater awareness and better mechanism to counter such attack in the cyberspace. Hence, this work presents an overview of the attack, identifies the impact of FDIA in critical domains, and talks about the countermeasures. A taxonomy of the existing countermeasures to defend against FDIA is provided. Unlike other works, we propose some evaluation metrics for FDIA detection and also highlight the scarcity of benchmark datasets to validate the performance of FDIA detection techniques.
Learning Management Systems (LMS) is now an emergent technology where massive data are collected and requires handling. This data comes from different sources with multiple features which represents another complex paradigm. However, as part of business intelligence and decision support, this data needs to be classified and analyzed for the management, teachers, as well as students to make the appropriate decisions. Thus, one of the effective data analysis methods is clustering. However, LMS data encompasses multi-features, which are not sufficient to make appropriate decisions. Therefore, single feature clustering algorithms would not help LMS decision-makers. Consequently, multifeatured/multiobjective clustering algorithms could be one of the proposed solutions. Thus, looking at different multiobjective clustering algorithms as compared to the LMS nature of data, those algorithms do not satisfy the clustering purpose. In addition, the LMS data could be huge, complex, and sequential algorithms would not help as well. Thus, this paper is a step forward towards clustering LMS data for better decision making. The paper proposes a new clustering framework based upon distributed systems and a new multiobjective algorithm for the purpose of LMS clustering. The algorithm has been examined experimentally in order to answer some of the questions that help taking decision based upon LMS collected data.
Book details Scott E. Page The Model Thinker: What You Need to Know to Make Data Work for You. Hatchett Book Group. 448 pages; ISBN-10: 0465094627; ISBN-13: 978-0465094622. 18.56 USD.
The generation of synthetic data is an essential tool to study complex systems, allowing for example to test models of these in precisely controlled settings, or to parametrize simulation models when data is missing. This paper focuses on the generation of synthetic data with an emphasis on correlation structure. We introduce a new methodology to generate such correlated synthetic data. It is implemented in the field of socio-spatial systems, more precisely by coupling an urban growth model with a transportation network generation model. We also show the genericity of the method with an application on financial time-series. The simulation results show that the generation of correlated synthetic data for such systems is indeed feasible within a broad range of correlations, and suggest applications of such synthetic datasets.
Book details De Nooy W., Mrvar A., and Batagelj V. Exploratory Social Network Analysis with Pajek 3rd (Expanded) Edition Cambridge: Cambridge University Press; 2018. 334 pages, ISBN 978-1-108-56569-1
With the decline of Moore’s law and the ever increasing availability of cheap massively parallel hardware, it becomes more and more important to embrace parallel programming methods to implement Agent-Based Simulations (ABS). This has been acknowledged in the field a while ago and numerous research on distributed parallel ABS exists, focusing primarily on Parallel Discrete Event Simulation as the underlying mechanism. However, these concepts and tools are inherently difficult to master and apply and often an excess in case implementers simply want to parallelise their own, custom agent-based model implementation. However, with the established programming languages in the field, Python, Java and C++, it is not easy to address the complexities of parallel programming due to unrestricted side effects and the intricacies of low-level locking semantics. Therefore, in this paper we propose the use of a lock-free approach to parallel ABS using Software Transactional Memory (STM) in conjunction with the pure functional programming language Haskell, which in combination, removes some of the problems and complexities of parallel implementations in imperative approaches. We present two case studies, in which we compare the performance of lock-based and lock-free STM implementations in two different well known Agent-Based Models, where we investigate both the scaling performance under increasing number of CPU cores and the scaling performance under increasing number of agents. We show that the lock-free STM implementations consistently outperform the lock-based ones and scale much better to increasing number of CPU cores both on local hardware and on Amazon EC. Further, by utilizing the pure functional language Haskell we gain the benefits of immutable data and lack of unrestricted side effects guaranteed at compile-time, making validation easier and leading to increased confidence in the correctness of an implementation, something of fundamental importance and benefit in parallel programming in general and scientific computing like ABS in particular.
Book details Authors: Kwang-Yong Kim, Abdus Samad, Ernesto Benini Title: Design Optimization of Fluid Machinery: Applying Computational Fluid Dynamics and Numerical Optimization ISBN: 9781119188308 (ePub) Published by: JohnWiley & Sons Singapore Pte. Ltd; 2019
Mobile contactless payment (MCP) is the future technology that is used for mobile payments, mobile wallet, transportation, and for mobile coupons. Existing solutions in this realm do not ensure end-to-end communication, information privacy, and the client’s anonymity. In order to overcome these flaws, we propose a secure and privacy preserving mobile commerce (SPPMC) framework for near-field communication (NFC) based proximity payments. SPPMC framework achieves both communication and information privacy. It ensures the client’s anonymity by making use of traceable anonymous certificates (TAC). Grid of secure elements (GSE) is used at the banking servers. The cost of computation and communication is very less. SPPMC ensures end-to-end security and withstands any type of known attack including multi-protocol attack. SPPMC is successfully verified using Burrows–Abadi–Needham (BAN) logic and Scyther tool. It ensures all the security properties.
The use of online social media is also connected with the real world. A very common example of this is the effect of social media coverage on the chances of success of elections. Previous literature has identified that the outcome of elections can often be predicted based on online public discussions. These discussions can be across various online social network with a special focus on the candidate's own accounts. Among many other forms of social media, Wikipedia is a very widely-used self-organizing information resource. The management and administration of Wikipedia is performed using special users which are elected by means of online public elections. In other words, the results of these elections pose as an emergent outcome of a large-scale self-organized opinion formation process. However, due to dynamical, and non-linear interactions besides the presence of mutual dependencies between election participants, a statistical analysis of this data can both be cumbersome as well as inefficient in terms of information extraction. We believe that social network analysis is a more appropriate alternative. It allows for the identification of local and global patterns, identification of influential nodes as well as the contacts involved in the influence. In general, this particular analytic technique can help in examining the internal complex network dynamics. In the current paper, we investigates whether personal contacts matter more than know-how contacts in wiki election nominations and voting participation. We employ the use of standard social network analysis tools such as Pajek and Gephi. The presented work demonstrates the significance of personal contacts over know-how contacts of a person in online elections. We have discovered that personal contacts, i.e. immediate neighbors (based on degree centrality) and neighborhood (k-neighbors) of a person have a positive effect on a person’s nomination as an administrator and also contribute to the active participation of voters in voting. Moreover, know-how contacts, analyzed by means of measures such as betweenness and closeness centralities, have a relatively insignificant effect on the selection of a person. However, know-how contacts, measured in terms of betweenness centrality can positively contribute only to the voting process—primarily due to the role played in passing information around the network. These contacts, also measured in terms of influence domain and PageRank, can play a vital role in the selection of an admin. Additionally, such contacts have a positive association with the voting process in terms of reachability and brokerage roles.
The current paper shows the multi-agents capabilities for valid and flexible applications when using a framework. Agent-based functions were used within JADE framework for an Android messaging application with all requirements included. In the paper are described the architecture, the main functions and the databases integration of a user friendly agent-based application. There are included existing and possible multi-agents characteristics to provide integration with mobile platforms and storage challenges to improve the user experience through data mining.
Purpose Smart grid can be considered as the next step in the evolution of power systems. It comprises of different entities and objects ranging from smart appliances, smart meters, generators, smart storages, and more. One key problem in modeling smart grid is that while currently there has previously been a considerable focus on the proof of concept aspect of smart grid, there have been very few modeling attempts and even lesser attempts at formalization. To the best of our knowledge, formal specification has not been applied previously in the domain of smart grid. Methods Using a state-based formal specification language namely Z (pronounced as ‘Zed’), we present a novel approach to formally modeling and specify smart grid components. Results The modeling exercise clearly demonstrates that Z is particularly suited for modeling various smart grid components. Conclusions The presented formal specification can be considered as a first step towards the modeling of smart grid using a Software Engineering formalism. It also demonstrates how formal specification can be used to model complex systems in general, and the smart grid, in particular.
