Scalable wireless sensor networks for dynamic communication environments: simulation and modelling

This thesis explores the deployment of Wireless Sensor Networks (WSNs) on localised maritime events. In particular, it will focus on the deployment of a WSN at sea and estimating what challenges derive from the environment and how they affect communication. This research addresses these challenges through simulation and modelling of communication and environment, evaluating the implications of hardware selection and custom algorithm development. The first part of this thesis consists of the analysis of aspects related to the Medium Access Control layer of the network stack in large-scale networks. These details are commonly hidden from upper layers, thus resulting in misconceptions of real deployment characteristics. Results show that simple solutions have greater advantages when the number of nodes within a cluster increases. The second part considers routing techniques, with focus on energy management and packet delivery. It is shown that, under certain conditions, relaying data can increase energy savings, while at the same time allows a more even distribution of its usage between nodes. The third part describes the development of a custom-made network simulator. It starts by considering realistic radio, channel and interference models to allow a trustworthy simulation of the deployment environment. The MAC and Routing techniques developed thus far are adapted to the simulator in a cross-layer manner. The fourth part consists of adapting the WSN behaviour to the variable weather and topology found in the chosen application scenario. By analysing the algorithms presented in this work, it is possible to find and use the best alternative under any set of environmental conditions. This mechanism, the environment-aware engine, uses both network and sensing data to optimise performance through a set of rules that involve message delivery and distance between origin and cluster hea

Enabling and Understanding Failure of Engineering Structures Using the Technique of Cohesive Elements

In this paper, we describe a cohesive zone model for the prediction of failure of engineering solids and/or structures. A damage evolution law is incorporated into a three-dimensional, exponential cohesive law to account for material degradation under the influence of cyclic loading. This cohesive zone model is implemented in the finite element software ABAQUS through a user defined subroutine. The irreversibility of the cohesive zone model is first verified and subsequently applied for studying cyclic crack growth in specimens experiencing different modes of fracture and/or failure. The crack growth behavior to include both crack initiation and crack propagation becomes a natural outcome of the numerical simulation. Numerical examples suggest that the irreversible cohesive zone model can serve as an efficient tool to predict fatigue crack growth. Key issues such as crack path deviation, convergence and mesh dependency are also discussed

IOT Based Real Time River Water Quality Monitoring and Control System

Water quality monitoring systems currently in use are manual and involve tedious processes that are time intensive. This research suggests a system with sensors for water quality monitoring. Access to real-time data may be obtained through remote monitoring and the Internet of Things. A wireless sensor network (WSN) contains a micro-controller for data processing, a mechanism for communicating between and inside nodes and many (IoT). Using Spark flow analysis with Spark MLlib, deep on it. The agent will receive a warning SMS automatically if the detected value exceeds the threshold. Our plan to develop a high- frequency, high-mobility, low-power water monitoring system makes it special. As a result, the Bangladeshi people will find our proposed approach highly useful in raising awareness of and putting an end to water pollution

Routing and Mobility on IPv6 over LoWPAN

The IoT means a world-wide network of interconnected objects based on standard communication protocols. An object in this context is a quotidian physical device augmented with sensing/actuating, processing, storing and communication capabilities. These objects must be able to interact with the surrounding environment where they are placed and to cooperate with neighbouring objects in order to accomplish a common objective. The IoT objects have also the capabilities of converting the sensed data into automated instructions and communicating them to other objects through the communication networks, avoiding the human intervention in several tasks. Most of IoT deployments are based on small devices with restricted computational resources and energy constraints. For this reason, initially the scientific community did not consider the use of IP protocol suite in this scenarios because there was the perception that it was too heavy to the available resources on such devices. Meanwhile, the scientific community and the industry started to rethink about the use of IP protocol suite in all IoT devices and now it is considered as the solution to provide connectivity between the IoT devices, independently of the Layer 2 protocol in use, and to connect them to the Internet. Despite the use of IP suite protocol in all devices and the amount of solutions proposed, many open issues remain unsolved in order to reach a seamless integration between the IoT and the Internet and to provide the conditions to IoT service widespread. This thesis addressed the challenges associated with the interconnectivity between the Internet and the IoT devices and with the security aspects of the IoT. In the interconnectivity between the IoT devices and the Internet the problem is how to provide valuable information to the Internet connected devices, independently of the supported IP protocol version, without being necessary accessed directly to the IoT nodes. In order to solve this problem, solutions based on Representational state transfer (REST) web services and IPv4 to IPv6 dual stack transition mechanism were proposed and evaluated. The REST web service and the transition mechanism runs only at the border router without penalizing the IoT constrained devices. The mitigation of the effects of internal and external security attacks minimizing the overhead imposed on the IoT devices is the security challenge addressed in this thesis. Three different solutions were proposed. The first is a mechanism to prevent remotely initiated transport level Denial of Service attacks that avoids the use of inefficient and hard to manage traditional firewalls. It is based on filtering at the border router the traffic received from the Internet and destined to the IoT network according to the conditions announced by each IoT device. The second is a network access security framework that can be used to control the nodes that have access to the network, based on administrative approval, and to enforce security compliance to the authorized nodes. The third is a network admission control framework that prevents IoT unauthorized nodes to communicate with IoT authorized nodes or with the Internet, which drastically reduces the number of possible security attacks. The network admission control was also exploited as a management mechanism as it can be used to manage the network size in terms of number of nodes, making the network more manageable, increasing its reliability and extending its lifetime.A IoT (Internet of Things) tem suscitado o interesse tanto da comunidade académica como da indústria, uma vez que os campos de aplicação são inúmeros assim como os potenciais ganhos que podem ser obtidos através do uso deste tipo de tecnologia. A IoT significa uma rede global de objetos ligados entre si através de uma rede de comunicações baseada em protocolos standard. Neste contexto, um objeto é um objeto físico do dia a dia ao qual foi adicionada a capacidade de medir e de atuar sobre variáveis físicas, de processar e armazenar dados e de comunicar. Estes objetos têm a capacidade de interagir com o meio ambiente envolvente e de cooperar com outros objetos vizinhos de forma a atingirem um objetivo comum. Estes objetos também têm a capacidade de converter os dados lidos em instruções e de as comunicar a outros objetos através da rede de comunicações, evitando desta forma a intervenção humana em diversas tarefas. A maior parte das concretizações de sistemas IoT são baseados em pequenos dispositivos autónomos com restrições ao nível dos recursos computacionais e de retenção de energia. Por esta razão, inicialmente a comunidade científica não considerou adequado o uso da pilha protocolar IP neste tipo de dispositivos, uma vez que havia a perceção de que era muito pesada para os recursos computacionais disponíveis. Entretanto, a comunidade científica e a indústria retomaram a discussão acerca dos benefícios do uso da pilha protocolar em todos os dispositivos da IoT e atualmente é considerada a solução para estabelecer a conetividade entre os dispositivos IoT independentemente do protocolo da camada dois em uso e para os ligar à Internet. Apesar do uso da pilha protocolar IP em todos os dispositivos e da quantidade de soluções propostas, são vários os problemas por resolver no que concerne à integração contínua e sem interrupções da IoT na Internet e de criar as condições para a adoção generalizada deste tipo de tecnologias. Esta tese versa sobre os desafios associados à integração da IoT na Internet e dos aspetos de segurança da IoT. Relativamente à integração da IoT na Internet o problema é como fornecer informação válida aos dispositivos ligados à Internet, independentemente da versão do protocolo IP em uso, evitando o acesso direto aos dispositivos IoT. Para a resolução deste problema foram propostas e avaliadas soluções baseadas em web services REST e em mecanismos de transição IPv4 para IPv6 do tipo pilha dupla (dual stack). O web service e o mecanismo de transição são suportados apenas no router de fronteira, sem penalizar os dispositivos IoT. No que concerne à segurança, o problema é mitigar os efeitos dos ataques de segurança internos e externos iniciados local e remotamente. Foram propostas três soluções diferentes, a primeira é um mecanismo que minimiza os efeitos dos ataques de negação de serviço com origem na Internet e que evita o uso de mecanismos de firewalls ineficientes e de gestão complexa. Este mecanismo filtra no router de fronteira o tráfego com origem na Internet é destinado à IoT de acordo com as condições anunciadas por cada um dos dispositivos IoT da rede. A segunda solução, é uma framework de network admission control que controla quais os dispositivos que podem aceder à rede com base na autorização administrativa e que aplica políticas de conformidade relativas à segurança aos dispositivos autorizados. A terceira é um mecanismo de network admission control para redes 6LoWPAN que evita que dispositivos não autorizados comuniquem com outros dispositivos legítimos e com a Internet o que reduz drasticamente o número de ataques à segurança. Este mecanismo também foi explorado como um mecanismo de gestão uma vez que pode ser utilizado a dimensão da rede quanto ao número de dispositivos, tornando-a mais fácil de gerir e aumentando a sua fiabilidade e o seu tempo de vida

Navigating the IoT landscape: Unraveling forensics, security issues, applications, research challenges, and future

Given the exponential expansion of the internet, the possibilities of security attacks and cybercrimes have increased accordingly. However, poorly implemented security mechanisms in the Internet of Things (IoT) devices make them susceptible to cyberattacks, which can directly affect users. IoT forensics is thus needed for investigating and mitigating such attacks. While many works have examined IoT applications and challenges, only a few have focused on both the forensic and security issues in IoT. Therefore, this paper reviews forensic and security issues associated with IoT in different fields. Future prospects and challenges in IoT research and development are also highlighted. As demonstrated in the literature, most IoT devices are vulnerable to attacks due to a lack of standardized security measures. Unauthorized users could get access, compromise data, and even benefit from control of critical infrastructure. To fulfil the security-conscious needs of consumers, IoT can be used to develop a smart home system by designing a FLIP-based system that is highly scalable and adaptable. Utilizing a blockchain-based authentication mechanism with a multi-chain structure can provide additional security protection between different trust domains. Deep learning can be utilized to develop a network forensics framework with a high-performing system for detecting and tracking cyberattack incidents. Moreover, researchers should consider limiting the amount of data created and delivered when using big data to develop IoT-based smart systems. The findings of this review will stimulate academics to seek potential solutions for the identified issues, thereby advancing the IoT field.Comment: 77 pages, 5 figures, 5 table

Determining Additional Modulus of Subgarde Reaction Based on Tolerable Settlement for the Nailed-slab System Resting on Soft Clay.

Abstract—Nailed-slab System is a proposed alternative solution for rigid pavement problem on soft soils. Equivalent modulus of subgrade reaction (k’) can be used in designing of nailed-slab system. This modular is the cumulative of modulus of subgrade reaction from plate load test (k) and additional modulus of subgrade reaction due to pile installing (∆∆∆∆k). A recent method has used reduction of pile resistance approach in determining ∆∆∆∆k. The relative displacement between pile and soils, and reduction of pile resistance has been identified. In fact, determining of reduction of pile resistance is difficult. This paper proposes an approach by considering tolerable settlement of rigid pavement. Validation is carried out with respect to a loading test of nailed-slab models. The models are presented as strip section of rigid pavement. The theory of beams on elastic foundation is used to calculate the slab deflection by using k’. Proposed approach can results in deflection prediction close to observed one. In practice, the Nailed-slab System would be constructed by multiple-row piles. Designing this system based on one-pile row analysis will give more safety design and will consume less time