55 research outputs found
Improving the Scalability of DPWS-Based Networked Infrastructures
The Devices Profile for Web Services (DPWS) specification enables seamless
discovery, configuration, and interoperability of networked devices in various
settings, ranging from home automation and multimedia to manufacturing
equipment and data centers. Unfortunately, the sheer simplicity of event
notification mechanisms that makes it fit for resource-constrained devices,
makes it hard to scale to large infrastructures with more stringent
dependability requirements, ironically, where self-configuration would be most
useful. In this report, we address this challenge with a proposal to integrate
gossip-based dissemination in DPWS, thus maintaining compatibility with
original assumptions of the specification, and avoiding a centralized
configuration server or custom black-box middleware components. In detail, we
show how our approach provides an evolutionary and non-intrusive solution to
the scalability limitations of DPWS and experimentally evaluate it with an
implementation based on the the Web Services for Devices (WS4D) Java Multi
Edition DPWS Stack (JMEDS).Comment: 28 pages, Technical Repor
A peer-to-peer service architecture for the Smart Grid
Short paperThe Smart Grid vision needs to address hard challenges such as interoperability, reliability and scalability before it can become fulfilled. The need to provide full interoperability between current and future energy and non-energy systems and its disparate technologies along with the problem of seamless discovery, configuration, and communication of a large variety of networked devices ranging from the resource constrained sensing devices to the large machines inside a data center requires an agnostic Service Oriented Architecture. Moreover, the sheer scale of the Smart Grid and the criticality of the communication among its subsystems for proper management, demands a scalable and reliable communication framework able to work in an heterogeneous and dynamic environment. In this position paper, we propose a generic framework, based on Web Services for interoperability, and epidemic or gossip based communication protocols for reliability and scalability, that can serve a general management substrate where several Smart Grid problems can be solved. We illustrate the flexibility of the proposed framework by showing how it can be used in two specific scenarios.Important challenges in interoperability, reliability, and scalability need to be addressed before the Smart Grid vision can be fulfilled. The sheer scale of the electric grid and the criticality of the communication among its subsystems for proper management, demands a scalable and reliable communication framework able to work in an heterogeneous and dynamic environment. Moreover, the need to provide full interoperability between diverse current and future energy and non-energy systems, along with seamless discovery and configuration of a large variety of networked devices, ranging from the resource constrained sensing devices to servers in data centers, requires an implementation-agnostic Service Oriented Architecture. In this position paper we propose that this challenge can be addressed with a generic framework that reconciles the reliability and scalability of Peer-to-Peer systems, with the industrial standard interoperability of Web Services. We illustrate the flexibility of the proposed framework by showing how it can be used in two specific scenarios
A Real-Time Service-Oriented Architecture for Industrial Automation
Industrial automation platforms are experiencing a paradigm shift. New technologies are making their way in the area, including embedded real-time systems, standard local area networks like Ethernet, Wi-Fi and ZigBee, IP-based communication protocols, standard service oriented architectures (SOAs) and Web services. An automation system will be composed of flexible autonomous components with plug & play functionality, self configuration and diagnostics, and autonomic local control that communicate through standard networking technologies. However, the introduction of these new technologies raises important problems that need to be properly solved, one of these being the need to support real-time and quality-of-service (QoS) for real-time applications. This paper describes a SOA enhanced with real-time capabilities for industrial automation. The proposed architecture allows for negotiation of the QoS requested by clients from Web services, and provides temporal encapsulation of individual activities. This way, it is possible to perform an a priori analysis of the temporal behavior of each service, and to avoid unwanted interference among them. After describing the architecture, experimental results gathered on a real implementation of the framework (which leverages a soft real-time scheduler for the Linux kernel) are presented, showing the effectiveness of the proposed solution. The experiments were performed on simple case studies designed in the context of industrial automation applications
Distributed Hybrid Simulation of the Internet of Things and Smart Territories
This paper deals with the use of hybrid simulation to build and compose
heterogeneous simulation scenarios that can be proficiently exploited to model
and represent the Internet of Things (IoT). Hybrid simulation is a methodology
that combines multiple modalities of modeling/simulation. Complex scenarios are
decomposed into simpler ones, each one being simulated through a specific
simulation strategy. All these simulation building blocks are then synchronized
and coordinated. This simulation methodology is an ideal one to represent IoT
setups, which are usually very demanding, due to the heterogeneity of possible
scenarios arising from the massive deployment of an enormous amount of sensors
and devices. We present a use case concerned with the distributed simulation of
smart territories, a novel view of decentralized geographical spaces that,
thanks to the use of IoT, builds ICT services to manage resources in a way that
is sustainable and not harmful to the environment. Three different simulation
models are combined together, namely, an adaptive agent-based parallel and
distributed simulator, an OMNeT++ based discrete event simulator and a
script-language simulator based on MATLAB. Results from a performance analysis
confirm the viability of using hybrid simulation to model complex IoT
scenarios.Comment: arXiv admin note: substantial text overlap with arXiv:1605.0487
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Middleware architectures for the smart grid: A survey on the state-of-the-art, taxonomy and main open issues
The integration of small-scale renewable energy sources in the smart grid depends on several challenges that must be overcome. One of them is the presence of devices with very different characteristics present in the grid or how they can interact among them in terms of interoperability and data sharing. While this issue is usually solved by implementing a middleware layer among the available pieces of equipment in order to hide any hardware heterogeneity and offer the application layer a collection of homogenous resources to access lower levels, the variety and differences among them make the definition of what is needed in each particular case challenging. This paper offers a description of the most prominent middleware architectures for the smart grid and assesses the functionalities they have, considering the performance and features expected from them in the context of this application domain
AGNI: an API for the control of automomous service robots
With the continuum growth of Internet connected devices, the scalability of the
protocols used for communication between them is facing a new set of challenges. In
robotics these communications protocols are an essential element, and must be able to
accomplish with the desired communication.
In a context of a multi-‐‑agent platform, the main types of Internet communication
protocols used in robotics, mission planning and task allocation problems will be
revised. It will be defined how to represent a message and how to cope with their
transport between devices in a distributed environment, reviewing all the layers of the
messaging process.
A review of the ROS platform is also presented with the intent of integrating the
already existing communication protocols with the ServRobot, a mobile autonomous
robot, and the DVA, a distributed autonomous surveillance system. This is done with
the objective of assigning missions to ServRobot in a security context
Ensuring Cyber-Security in Smart Railway Surveillance with SHIELD
Modern railways feature increasingly complex embedded computing systems for surveillance, that are moving towards fully wireless smart-sensors. Those systems are aimed at monitoring system status from a physical-security viewpoint, in order to detect intrusions and other environmental anomalies. However, the same systems used for physical-security surveillance are vulnerable to cyber-security threats, since they feature distributed hardware and software architectures often interconnected by ‘open networks’, like wireless channels and the Internet. In this paper, we show how the integrated approach to Security, Privacy and Dependability (SPD) in embedded systems provided by the SHIELD framework (developed within the EU funded pSHIELD and nSHIELD research projects) can be applied to railway surveillance systems in order to measure and improve their SPD level. SHIELD implements a layered architecture (node, network, middleware and overlay) and orchestrates SPD mechanisms based on ontology models, appropriate metrics and composability. The results of prototypical application to a real-world demonstrator show the effectiveness of SHIELD and justify its practical applicability in industrial settings
A real time demonstrative analysis of lightweight payload encryption in resource constrained devices based on mqtt
06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Kısıtlı cihazların kaynakları, yani bellek (ROM ve RAM), CPU ve pil ömrü (varsa) sınırlıdır. Genellikle, veri toplayan sensörler, makinadan makineye (M2M) veya servisleri ve elektrikli ev aletlerini kontrol eden akıllı cihazlar için puanlar. Bu tür aygıtlar bir ağa bağlandığında "nesnelerin Internet'i" nin (IoT) bir parçasını oluştururlar. Message Queue Telemetry Transport (yani MQTT), hafif, açık, basit, istemci-sunucu yayın/abone mesajlaşma taşıma protokolüdür. Güvenilir iletişim için üç Hizmet Kalitesi (QoS) seviyesini destekleyen çoğu kaynak kısıtlamalı IoT cihazı için kullanışlıdır ve verimlidir. Cihazdan Cihaza (D2D) ve nesnelerin Internet'i (IoT) bağlamları gibi kısıtlı ortamlarda iletişim için gerekli olan bir protokoldür. MQTT protokolü, güvenli soket katmanı (SSL) sertifikalarına dayalı taşıma katmanı güvenliği (TLS) dışında somut güvenlik mekanizmalarından yoksundur. Bununla birlikte, bu güvenlik protokollerinin en hafif değildir ve özellikle kısıtlı cihazlar için ağ yüklerini artırır. IoT cihazlarının yaklaşık %70'inde özellikle de istemci tarafında veri şifrelemesi yoktur ve TLS için mükemmel bir alternatif olabilir. Bu tezde, farklı Hizmet Kalitesi (QoS) ve veri yüklerin değişken boyutu için kısıtlı bir cihaz üzerinde MQTT protokolünün ağ performansı üzerindeki etkisini göstermek için bir deney düzeneği tasarlanmıştır. Bu çalışmanın yeni kısmı, yüklerin istemci tarafında şifrelenmesini ve ağ performansı üzerindeki etkisini kapsıyor. Denemelerde, verilere 128-bits ileileri şifreleme standardı (AES) hafif bir şifreleme uygulanmıştır. Mesajlar, farklı yük boyutlarına dayanan bir komisyoncu sunucusu aracılığıyla gerçek kablolu alt uçtakı yayıncılık istemcisi ve düşük uçtakı abone istemcisi üzerinden MQTT'deki üç farklı QoS seviyesini kullanarak aktarılır. Paketler, şifreleme ve şifre çözme işlem süresinin ölçülmesiyle birlikte uçtan uca gecikme, verimlilik ve mesaj kaybı analiz etmek için yakalanır. Deney sonuçlarına göre, şifrelenmemiş (şifresiz metin) yükün daha düşük bir ağ yük etkisine sahip olduğu ve bu nedenle, yüzde kaybı ve mesaj tesliminde, şifreli yüke göre MQTT'yi kullanarak nispeten daha iyi bir ağ performansı ürettiği sonucuna varılmıştır.Constrained devices are limited in resources namely, memory (ROM and RAM), CPU and battery life (if available). They are often used as sensors that collects data, machine to machine (M2M) or smart devices that control services and electrical appliances. When such devices are connected to a network they form what is called "things" and in a whole, they form part of the "Internet of Things" (IoT). Message Queue Telemetry Transport (MQTT) is a common light weight, open, simple, client-server publish/subscribe messaging transport protocol useful and efficient for most resource constrained IoT devices that supports three Quality of Service (QoS) levels for reliable communication. It is an essential protocol for communication in constrained environments such as Device to Device (D2D) and Internet of Things (IoT) contexts. MQTT protocol is devoid of concrete security mechanisms apart from Transport Layer Security (TLS) based on Secure Socket Layer (SSL) certificates. However, this is not the lightest of security protocols and increases network overheads especially for constrained devices. About 70 % of most ordinary IoT devices also lack data encryption especially at the client-end which could have been a perfect alternative for TLS. In this thesis, an experimental setup is designed to demonstrate the effect on network performance of MQTT protocol on a constrained device for different Quality of Service (QoS) and variable size of payloads. The novel part of this study covers client-side encryption of payloads and its effect over network performance. In the experiments, a lightweight encryption of 128-bits Advanced Encryption Standard (AES) is applied on the data. The messages are transferred using the three different QoS levels in MQTT over real wired low-end publish client and low-end subscriber client via a broker server based on different payload sizes. The packets are captured to analyze end-to-end latency, throughput and message loss along with the measurement of encryption and decryption processing time. According to the results of the experiment, it was concluded that, non-encrypted (plaintext) payload have a lower network load effect and hence produces a relatively better network performance using MQTT in terms of percentage loss and message delivery than the encrypted payload
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