A Taxonomy on Misbehaving Nodes in Delay Tolerant Networks

Delay Tolerant Networks (DTNs) are type of Intermittently Connected Networks (ICNs) featured by long delay, intermittent connectivity, asymmetric data rates and high error rates. DTNs have been primarily developed for InterPlanetary Networks (IPNs), however, have shown promising potential in challenged networks i.e. DakNet, ZebraNet, KioskNet and WiderNet. Due to unique nature of intermittent connectivity and long delay, DTNs face challenges in routing, key management, privacy, fragmentation and misbehaving nodes. Here, misbehaving nodes i.e. malicious and selfish nodes launch various attacks including flood, packet drop and fake packets attack, inevitably overuse scarce resources (e.g., buffer and bandwidth) in DTNs. The focus of this survey is on a review of misbehaving node attacks, and detection algorithms. We firstly classify various of attacks depending on the type of misbehaving nodes. Then, detection algorithms for these misbehaving nodes are categorized depending on preventive and detective based features. The panoramic view on misbehaving nodes and detection algorithms are further analyzed, evaluated mathematically through a number of performance metrics. Future directions guiding this topic are also presented

Blockchain for Cities—A Systematic Literature Review

Blockchain is considered one of the most disruptive technologies of our time. Numerous cities around the world are launching blockchain initiatives as part of the overall efforts toward shaping the urban future. However, the infancy stage of the blockchain industry leads to a severe gap between the knowledge we have and the actions urban policy makers are taking. This paper is an effort to narrow this rift. We provide a systematic literature review on concrete blockchain use cases proposed by the research community. At the macro-level, we discuss and organize use cases from 159 selected papers into nine sectors recognized as crucial for sustainable and smart urban future. At the micro-level, we identify a component-based framework and analyze the design and prototypes of blockchain systems studied in a subset of 71 papers. The high-level use case review allows us to illustrate the relationship between them and the four pillars of urban sustainability: social, economic, environmental, and governmental. The system level analysis helps us highlight interesting inconsistencies between well-known blockchain applicability decision rules and the approaches taken by the literature. We also offer two classification methodologies for blockchain use cases and elaborate on how they can be applied to stimulate cross-sector insights in the blockchain knowledge domain

Generic access to symbolic computing services

Symbolic computation is one of the computational domains that requires large computational resources. Computer Algebra Systems (CAS), the main tools used for symbolic computations, are mainly designed to be used as software tools installed on standalone machines that do not provide the required resources for solving large symbolic computation problems. In order to support symbolic computations an infrastructure built upon massively distributed computational environments must be developed. Building an infrastructure for symbolic computations requires a thorough analysis of the most important requirements raised by the symbolic computation world and must be built based on the most suitable architectural styles and technologies. The architecture that we propose is composed of several main components: the Computer Algebra System (CAS) Server that exposes the functionality implemented by one or more supporting CASs through generic interfaces of Grid Services; the Architecture for Grid Symbolic Services Orchestration (AGSSO) Server that allows seamless composition of CAS Server capabilities; and client side libraries to assist the users in describing workflows for symbolic computations directly within the CAS environment. We have also designed and developed a framework for automatic data management of mathematical content that relies on OpenMath encoding. To support the validation and fine tuning of the system we have developed a simulation platform that mimics the environment on which the architecture is deployed

Smart cities : concepts, perceptions and lessons for planners

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 127-137).Today, there appears to be a visible trend in the use of the "smart" prefix. For example, cities are branding themselves as, or striving to become "smart" cities. Planners and policy-makers espouse "smart growth". Infrastructure planning involves "smart grids" for energy, "smart networks" for information and communications technologies (ICTs) and "smart mobility" in transportation. The "smart" term has also been stretched, where being "smart" is trounced by being "smarter". Being "smart", or "smarter", is perhaps seen as the next frontier for city planning, policy-making and management. A common underlying theme in "smart" cities is the application of technology to city planning and management, that leads to greater optimization of time and resources. However, definitions of "smart" cities remain elusive, and an inadequate understanding may lead cities to possible image or technological traps, heavy investments in ICTs and infrastructure without maximizing their potential, or to focus on "smart" technologies for short-term solutions without adequately considering the long term. As cities grapple with rapid urbanization and goals for sustainable development, resource management and climate change mitigation, learning about being "smart" will be timely and invaluable for planners. This study examines six "smart" cities - Boston, San Francisco, Amsterdam, Stockholm, Singapore and Rio de Janeiro - assessing city officials' perceptions and concepts of "smart cities" and their "smart" initiatives. Their efforts and approaches are analyzed against four theories of "smart" cities; (a) "smart machines" and organization, (b) engaging communities, organizations and businesses, (c) learning and adaptation, and (d) investing for the future. From the research, learning points and best practices are extracted, to serve as an applicable guide for cities as they embark on their "smart" initiatives.by Tuan-Yee Ching.M.C.P