Polytechnic Institute of Porto
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Gullies mitigation and control measures: A case study of the Seirós gullies (North of Portugal)
No full text4th International Conference on Ecohydrology, Soil and Climate Change, EcoHCC'2017It is known that the erosion process triggered by gullies contributes to significant soil loss and land degradation, and this can limit the options for the occupation and development of a territory in terms of the suitability and quality of the farmland area. The variety of physical factors associated with gully formation hinders straightforward interpretations and requires well-grounded analysis based on local observation.
This work presents an example of gullies formed in a colluvial hill-slope agricultural area in Seirós, North of Portugal. The gullies were formed by intense rainfall events in 2015 that led to a channel overflowing. The channel in question was 49 m long, 0.50 m wide and 0.50 m deep and had been built by the landowner to protect his farmland from hillslope drainage. The adequacy of the strategy implemented to prevent gully formation with a view to the rehabilitation of the area is validated.info:eu-repo/semantics/publishedVersio
Routing heuristics for load-balanced transmission in TSN-based networks
No full textA carefully designed routing synthesis can help system designers achieve a better load balancing in TSN-based networks and avoid congestion. To this end purpose, this work proposes two heuristics referred to as (1) LB-DRR, which aims at achieving a better load balancing and compute as much disjoint routing paths as possible for each replicated flow; and (2) CR-DRR, which recomputes paths for time-sensitive flows in congestion situations. Extensive simulations demonstrate that the proposed approach outperforms the classical Shortest Path (SPA) and the weighted Equal Cost Multi-path (wt-ECMP) algorithms in terms of the maximum load transmitted on a link by more than 70% and 20%, respectively.info:eu-repo/semantics/publishedVersio
Taming Hierarchical Connectors
No full textBuilding and maintaining complex systems requires good
software engineering practices, including code modularity and reuse. The
same applies in the context of coordination of complex component-based
systems. This paper investigates how to verify properties of complex coordination patterns built hierarchically, i.e., built from composing blocks
that are in turn built from smaller blocks. Most existing approaches to
verify properties flatten these hierarchical models before the verification
process, losing the hierarchical structure. We propose an approach to verify hierarchical models using containers as actions; more concretely, containers interacting with their neighbours. We present a dynamic modal
logic tailored for hierarchical connectors, using Reo and Petri Nets to
illustrate our approach. We realise our approach via a prototype implementation available online to verify hierarchical Reo connectors, encoding connectors and formulas into mCRL2 specifications and formulasinfo:eu-repo/semantics/publishedVersio
Adaptive Terminal-Integral Sliding Mode Force Control of Elastic Joint Robot Manipulators in the Presence of Hysteresis
No full textPart of the Advances in Intelligent Systems and Computing book series (AISC, volume 1058)In this paper, an adaptive terminal-integral sliding mode force control of elastic joint robot manipulators in the presence of hysteresis is proposed. One of the most important issues that is solved in this study is that the hysteresis phenomenon is considered something that provokes losses in the manipulator motion and controller errors. Force control is necessary because it can be implemented and very useful in the area of industrial robotics such as collaborative and cooperative robotics. Therefore, it can be implemented for precise control in which robot-operator or robot-robot interaction is needed. An adaptive terminal-integral sliding mode force control is proposed by considering the hysteresis and the effects between the end effector and a flexible environment. Force control has not been studied extensively nowadays and even less for elastic joint robot manipulators. Thus, to improve the system precision control, the adaptive sliding mode controller (ASMC) is designed by a Lyapunov approach obtaining the adaptive and controller laws, respectively. As an experimental case study, two links elastic joint robot manipulator is considered by obtaining the elastic joint model with hysteresis using a Bouc-Wen model.info:eu-repo/semantics/publishedVersio
Buffer-Aware Scheduling for UAV Relay Networks with Energy Fairness
No full textFor assisting data communications in human-unfriendly environments, Unmanned Aerial Vehicles (UAVs) are employed to relay data for ground sensors thanks to UAVs' flexible deployment, high mobility, and line-of-sight communications. In UAV relay networks, energy efficient data relay is critical due to limited battery of the ground sensing devices. In this paper, we propose a butter-aware transmission scheduling optimization to minimize the energy consumption of the ground devices under constraints of butter overflows and energy cost fairness on the ground devices. Moreover, we show that the problem is NP-complete and propose a heuristic algorithm to approximate the optimal scheduling solution in polynomial time. The performance of the proposed algorithm is evaluated in terms of network sizes, packet arrival rates, and fairness of the energy consumption. Numerical results confirm that the proposed scheduling algorithm reduces the energy consumption of the ground devices in a fair fashion, while the butter overflow constraint holds.info:eu-repo/semantics/publishedVersio
Deep Q-Learning based Resource Management in UAV-assisted Wireless Powered IoT Networks
No full textIn Unmanned Aerial Vehicle (UAV)-assisted Wireless Powered Internet of Things (IoT), the UAV is employed to charge the IoT nodes remotely via Wireless Power Transfer (WPT) and collect their data. A key challenge of resource management for WPT and data collection is preventing battery drainage and butter overflow of the ground IoT nodes in the presence of highly dynamic airborne channels. In this paper, we consider the resource management problem in practical scenarios, where the UAV has no a-prior information on battery levels and data queue lengths of the nodes. We formulate the resource management of UAV-assisted WPT and data collection as Markov Decision Process (MDP), where the states consist of battery levels and data queue lengths of the IoT nodes, channel qualities, and positions of the UAV. A deep Q-learning based resource management is proposed to minimize the overall data packet loss of the IoT nodes, by optimally deciding the IoT node for data collection and power transfer, and the associated modulation scheme of the IoT node.info:eu-repo/semantics/publishedVersio
Attack Detection in Cyber-Physical Production Systems using the Deterministic Dendritic Cell Algorithm
No full textCyber-Physical Production Systems (CPPS) are key enablers for industrial and economic growth. The introduction of the Internet of Things (IoT) in industrial processes represents a new revolution towards the Smart Manufacturing oncept and is usually designated as the 4 th Industrial Revolution. Despite the huge interest from the industry to innovate their production systems, in order to increase revenues at lower costs, the IoT concept is still immature and fuzzy, which increases security related risks in industrial systems. Facing this paradigm and, since CPPS have reached a level of complexity, where the human intervention for operation and control is becoming increasingly difficult, Smart Factories require autonomic methodologies for security management and self-healing. This paper presents an Intrusion Detection System (IDS) approach for CPPS, based on the deterministic Dendritic Cell Algorithm (dDCA). To evaluate the dDCA effectiveness, a testing dataset was generated, by implementing and injecting various attacks on a OPC UA based CPPS testbed. The results show that these attacks can be successfully detected using the dDCA.info:eu-repo/semantics/publishedVersio
A Commodity SBC-Edge Cluster for Smart Cities
No full textThe commodity Single Board Computers (SBCs)
are increasingly becoming powerful and can execute standard
operating systems and mainstream workloads. In the context
of cloud-based smart city applications, SBCs can be utilized as
Edge computing devices reducing the network communication.
In this paper, we investigate the design and implementation of
a SBC based edge cluster (SBC-EC) framework for a smart
parking application. Since SBCs are resource constrained devices,
we devise a container based framework for a lighter foot-print.
Kubernetes was used as an orchestration tool to orchestrate
various containers in the framework. To validate our approach,
we implemented a proof-of-concept of the SBC based Edge cluster
for a smart parking application, as a possible ioT use-case.Our
implementation shows that, the use of SBC devices at the edge of
a cloud based smart parking application is a cost effective and
low energy, green computing solution. The proposed framework
can be extended to similar cloud based applications in the context
of a smart city.info:eu-repo/semantics/publishedVersio
A Domain Specific Language for Automotive Systems Integration
No full textDeveloping complex safe and secure Cyber-Physical
Systems (CPS) applications for the automotive domain is typically
a complex task, due to the criticality inherent to this domain.
Considering such known complexity of the development process,
we propose a novel solution that aims to provide a quasiautomatic1
integration process between the different components
of such CPS systems via the support of a Domain Specific
Language (DSL) that provides several views of the system,
abstracting away the more technical implementation details,
while imposing system properties and restrictions that have the
potential to be formally verified (either statically or at run-time)
during design, and facilitates the process of customization and
quasi-automatic build and deployment processes. In this paper,
we briefly analyze the tools that are available and that cover
partially the characteristics of our envisioned DSL, describe its
building blocks, and show how it can be applied in a small,
yet sufficiently complex CPS application whose architecture is
very close to what we may expect for the modern and future
generation of CPS application in the automotive domain.info:eu-repo/semantics/publishedVersio
Security in Wireless Sensor Networks: A formal verification of protocols
No full textThe increase of the digitalization taking place in various industrial domains is leading developers towards the design and implementation of more and more complex networked control systems (NCS) supported by Wireless Sensor Networks (WSN). This naturally raises new challenges for the current WSN technology, namely in what concerns improved guarantees of technical aspects such as real-time communications together with safe and secure transmissions. Notably, in what concerns security aspects, several cryptographic protocols have been proposed. Since the design of these protocols is usually error-prone, security breaches can still be exposed and MALICIOUSly exploited unless they are rigorously analyzed and verified. In this paper we formally verify, using ProVerif, three cryptographic protocols used in WSN, regarding the security properties of secrecy and authenticity. The security analysis performed in this paper is more robust than the ones performed in related work. Our contributions involve analyzing protocols that were modeled considering an unbounded number of participants and actions, and also the use of a hierarchical system to classify the authenticity results. Our verification shows that the three analyzed protocols guarantee secrecy, but can only provide authenticity in specific scenarios.info:eu-repo/semantics/publishedVersio