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  • 1.
    Alexander, Karlsson
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Design and Development of a Wireless Multipoint E-stop System for Autonomous Haulers2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Safety-related functions are important in autonomous industrial applications and are featured in an extensive body of work contained within the standards. The implementation of safety-related systems is commonly done by an external company at a great cost and with limited flexibility. Thus, the objective of this thesis was to develop and implement a safety-related system using o-the-shelf products and to analyse how well it can comply with the established standards of safety-related functions. This work has sought to review the current standards for safety-functions, the eectsof harsh radio environments on safety-related systems, and how to validate the safety-function.The system development process was used to gain knowledge by rst building the concept based on pre-study. After the pre-study was nished, the process moved to the development of software, designed to maintain a wireless heartbeat as well as to prevent collisions between the autonomous and manual-driven vehicles at a quarry, and implementation of the system in real hardware. Finally, a set of software (simulations) and hardware (measurements in an open-pit mine) tests were performed to test the functionality of the system. The wireless tests showed that the system adhered to the functional requirements set by the company, however, the evaluated performance level according to ISO 13849-1 resulted in performance level B which is insucient for a safety-related function. This work demonstrates that it is not possible to develop a safety-related system using the off-the-shelf products chosen, without hardware redundancy.

  • 2.
    Al-Rawi, Mohammed
    et al.
    Universidade de Aveiro, Portugal.
    Elmgren, Fredrik
    DeepVision AB, Linköping, Sweden.
    Frasheri, Mirgita
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Curuklu, Baran
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Yuan, Xin
    Universidad Politecnica de Madrid, Spain.
    Martínez, José-Fernán
    Universidad Politecnica de Madrid, Spain.
    Bastos, Joaquim
    Instituto de Telecomunicações - Pólo de Aveiro, Portugal.
    Rodriguez, Jonathan
    Universidade de Aveiro, Portugal.
    Pinto, Marc
    ECA Robotics, France.
    Algorithms for the Detection of First Bottom Returns and Objects in the Water Column in Side-Scan Sonar Images2017Ingår i: OCEANS '17 A Vision for our Marine Future OCEANS '17, Aberdeen, United Kingdom, 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    Underwater imaging has become an active research area in recent years as an effect of increased interest in underwater environments and is getting potential impact on the world economy, in what is called blue growth. Since sound propagates larger distances than electromagnetic waves underwater, sonar is typically used for underwater imaging. One interesting sonar image setting is comprised of using two parts (left and right) and is usually referred to as sidescan sonar. The image resulted from sidescan sonars, which is called waterfall image, usually has to distinctive parts, the water column and the image seabed. Therefore, the edge separating these two parts, which is called the first bottom return, is the real distance between the sonar and the seabed bottom (which is equivalent to sensor primary altitude). The sensory primary altitude can be measured if the imaging sonar is complemented by interferometric sonar, however, simple sonar systems have no way to measure the first bottom returns other than signal processing techniques. In this work, we propose two methods to detect the first bottom returns; the first is based on smoothing cubic spline regression and the second is based on a moving average filter to detect signal variations. The results of both methods are compared to the sensor primary altitude and have been successful in 22 images out of 25.

  • 3.
    Ashjaei, Mohammad
    Mälardalens högskola, Akademin för innovation, design och teknik. Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Multi-Hop Real-Time Communication over Switched Ethernet Technology2014Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Switched Ethernet technology has been introduced to be exploited in real-time communication systems due to its features such as its high throughput and wide availability, hence being a cost-effective solution. Many real-time switched Ethernet protocols have been developed, preserving the profits of traditional Ethernet technology, to overcome the limitations imposed by using commercially available (COTS) switches. These limitations mainly originate from the non-deterministic behavior of the Ethernet switches inherent in the use of FIFO queues and a limited number of priority levels.

     

    In our research we focus on two particular real-time communication technologies, one based on COTS Ethernet switches named the FTT-SE architecture and the other using a modified Ethernet switch called the HaRTES architecture. Both architectures are based on a master-slave technique supporting different and temporally isolated traffic types including real-time periodic, real-time sporadic and non-real-time traffic. Also, they provide mechanisms implementing adaptivity as a response to the requirements imposed by dynamic real-time applications. Nevertheless, the two mentioned architectures were originally developed for a simple network consisting of a single switch, and they were lacking support for multi-hop communication. In industrial applications, multi-hop communication is essential as the networks comprise a high number of nodes, that is far beyond the capability of a single switch.

     

    In this thesis, we study the challenges of building multi-hop communication using the FTT-SE and the HaRTES architectures. We propose different architectures to provide multi-hop communication while preserving the key characteristics of the single-switch architecture such as timeliness guarantee, resource efficiency, adaptivity and dynamicity. We develop a response time analysis for each proposed architecture and we compare them to assess their corresponding benefits and limitations. Further, we develop a simulation tool to evaluate the solutions.

  • 4.
    Avni, G.
    et al.
    IST Austria, Klosterneuburg, Austria.
    Goel, S.
    IIT Bombay, Mumbai, India.
    Henzinger, T. A.
    IST Austria, Klosterneuburg, Austria.
    Rodriguez-Navas, Guillermo
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Computing scores of forwarding schemes in switched networks with probabilistic faults2017Ingår i: Lecture Notes in Computer Science, Volume 10206, Springer Verlag , 2017, s. 169-187Konferensbidrag (Refereegranskat)
    Abstract [en]

    Time-triggered switched networks are a deterministic communication infrastructure used by real-time distributed embedded systems. Due to the criticality of the applications running over them, developers need to ensure that end-to-end communication is dependable and predictable. Traditional approaches assume static networks that are not flexible to changes caused by reconfigurations or, more importantly, faults, which are dealt with in the application using redundancy. We adopt the concept of handling faults in the switches from non-real-time networks while maintaining the required predictability. We study a class of forwarding schemes that can handle various types of failures. We consider probabilistic failures. For a given network with a forwarding scheme and a constant ℓ, we compute the score of the scheme, namely the probability (induced by faults) that at least ℓ messages arrive on time. We reduce the scoring problem to a reachability problem on a Markov chain with a “product-like” structure. Its special structure allows us to reason about it symbolically, and reduce the scoring problem to #SAT. Our solution is generic and can be adapted to different networks and other contexts. Also, we show the computational complexity of the scoring problem is #P-complete, and we study methods to estimate the score. We evaluate the effectiveness of our techniques with an implementation.

  • 5.
    Barac, Filip
    et al.
    Mid Sweden University.
    Yu, Kan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Gidlund, Mikael
    ABB, Corporate Research.
    Åkerberg, Johan
    ABB, Corporate Research.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Towards Reliable and Lightweight Communication in Industrial Wireless Sensor Networks2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we address the issues of timeliness and transmission reliability of existing industrial communication standards. We combine a Forward Error Correction coding schemeon the Medium Access Control layer with a lightweight routing protocol to form an IEEE 802.15.4-conformable solution, whichcan be implemented into already existing hardware without violating the standard. After laying the theoretical foundations,we conduct a performance evaluation of the proposed solution.The results show a substantial gain in reliability and reducedlatency, compared to the uncoded transmissions, as well ascommon Wireless Sensor Network routing protocols.

  • 6.
    Bergblomma, Marcus
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Ekström, Martin
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Ekström, Mikael
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Gerdtman, Christer
    Motion Control AB, Västerås, Sweden .
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik.
    A wireless low latency control system for harsh environments2012Ingår i: IFAC Proceedings Volumes (IFAC-PapersOnline): Vol. 11, PART 1, 2012, s. 17-22Konferensbidrag (Refereegranskat)
    Abstract [en]

    The use of wireless communication technologies in the industry offer severaladvantages. One advantage is the ability to deploy sensors where they previously could noteasily be deployed, for instance on parts that rotate. To use wireless communication in industrialcontrol loops, demands on reliability and latency requirements has to be met. This in anenvironment that may be harsh for radio communication. This work presents a reliable, lowlatency wireless communication system. The system is used in a wireless thyristor control loopin a hydro power plant generator. The wireless communication is based on Bluetooth radiomodules. The work shows a latency analysis together with empirical hardware based latencyand packet error rate measurements. The background noise of a hydro power plant station isalso investigated. The average latency between the Bluetooth modules for the proposed systemis 5.09 ms. The packet error rate is 0.00288 for the wireless low latency control system deployedin a hydro power plant.

  • 7.
    Castellanos Ardila, Julieth Patricia
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Gallina, Barbara
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Towards Efficiently Checking Compliance Against Automotive Security and Safety Standards2017Ingår i: The 7th IEEE International Workshop on Software Certification WoSoCer 2017, 2017, s. 317-324Konferensbidrag (Refereegranskat)
    Abstract [en]

    The growing connectivity of the systems that we rely on e.g. transportation vehicles is pushing towards the introduction of new standards aimed at providing a baseline to address cybersecurity besides safety. If the interplay of the two normative spaces is not mastered, compliance management might become more time consuming and costly, preventing engineers from dedicating their energies to system engineering. In this paper, we build on top of previous work aimed at increasing efficiency and confidence in compliance management. More specifically, we contribute to building a terminological framework needed to enable the systematization of commonalities and variabilities within ISO 26262 and SAE J3061. Then, we focus our attention on the requirements for software design and implementation and we use defeasible logic to prove compliance. Based on the compliance checking results, we reveal reuse opportunities. Finally, we draw our conclusions and sketch future research directions.

  • 8.
    Dao, Van-Lan
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Tran, Hung Vinh
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Girs, Svetlana
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Uhlemann, Elisabeth
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Reliability and Fairness for CANT Communication Based on Non-Orthogonal Multiple Access2019Ingår i: 2019 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS WORKSHOPS (ICC WORKSHOPS), IEEE , 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Recently, communication using unmanned aerial vehicles (LAVO as relay nodes has been considered beneficial for a number of applications. Moreover, nomorthogonM multiple access (NONIA) with users being assigned different signal passer levels while sharing the same tune-frequency domain has been found effective to enhance spectrum utilization and provide predictable access to the channel. Thus, in this paper we consider an UAV communication system with NOMA and propose a solution to find the optimal values for the user's power allocation coefficients (PA(s) needed to achieve the required levels of communication reliability. We present a closed-form expression for the PAC of each user and also propose an algori for finding the optimal altitude of the UAV required to satisfy the fairness condition for all users. Finally, we provide numerical mutinies and compare the results tar three types of communication environments.

  • 9.
    Feljan, Juraj
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Karapantelakis, A.
    Ericsson Research, Sweden.
    Mokrushin, L.
    Ericsson Research, Sweden.
    Inam, R.
    SOCNE, Sweden.
    Fersman, E.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Azevedo, C. R. B.
    University of Campinas, Brazil.
    Raizer, K.
    University of Campinas, Brazil.
    Souza, R. S.
    University of Campinas, Brazil.
    Tackling IoT complexity2017Ingår i: Ericsson review (English ed.), ISSN 0014-0171, Vol. 95, nr 2, s. 60-69Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Internet of Things (IoT) applications transcend traditional telecom to include enterprise verticals such as transportation, healthcare, agriculture, energy and utilities. Given the vast number of devices and heterogeneity of the applications, both ICT infrastructure and IoT application providers face unprecedented complexity challenges in terms of volume, privacy, interoperability and intelligence. Cognitive automation will be crucial to overcoming the intelligence challenge.

  • 10.
    Fernandez, Z.
    et al.
    Information and Communication Technologies Area, Ikerlan Technology Research Centre, Mondragón, Spain.
    Val, I.
    Information and Communication Technologies Area, Ikerlan Technology Research Centre, Mondragón, Spain.
    Mendicute, M.
    Signal Theory and Communications Area, Mondragon University, Mondragón, Spain.
    Uhlemann, Elisabeth
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Analysis and Evaluation of Self-Organizing TDMA for Industrial Applications2019Ingår i: IEEE International Workshop on Factory Communication Systems - Proceedings, WFCS, Institute of Electrical and Electronics Engineers Inc. , 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    With the Industry 4.0 revolution, the inclusion of wireless communications with real-time requirements has been gaining popularity in industrial applications. As existing wireless technologies do not fully satisfy the stringent requirements of the most critical industrial applications, wired, centralized networks are often used. However, when the application requires mobility, there is no other way than to use wireless communications. Further, in applications where the topology changes dynamically and a large number of devices are mobile, centralized protocols are less suitable. Unfortunately, most decentralized medium access protocols are not predictable, and thereby not able to fulfil the real-time requirements. To address these challenges, in this paper Self-Organizing Time Division Multiple Access (STDMA) is analysed to assess its suitability for use in industrial applications. The analysis has been carried out through simulations under a multipath dispersed time-variant industrial channel while subject to a variable Doppler shift. To this end, several metrics such as channel access delay, slot occupation distribution (SOD), packet losses and packet inter-arrival time (PIAT) have been evaluated, using OMNeT++ in combination with the VEINS framework. 

  • 11.
    Fotouhi, Hossein
    et al.
    CISTER/INESC-TEC, ISEP, Polytechnic Institute of Porto, Portuga.
    Alves, Mário
    CISTER/INESC-TEC, ISEP, Polytechnic Institute of Porto, Portuga.
    Zuniga, Marco
    Delft University of Technology, The Netherlands.
    Koubâa, Anis
    CISTER/INESC-TEC, ISEP, Polytechnic Institute of Porto, Portuga.
    Reliable and fast hand-offs in low-power wireless networks2014Ingår i: IEEE Transactions on Mobile Computing, ISSN 1536-1233, E-ISSN 1558-0660, Vol. 13, nr 11, s. 2620-2633Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hand-off (or hand-over), the process where mobile nodes select the best access point available to transfer data, has been well studied in wireless networks. The performance of a hand-off process depends on the specific characteristics of the wireless links. In the case of low-power wireless networks, hand-off decisions must be carefully taken by considering the unique properties of inexpensive low-power radios. This paper addresses the design, implementation and evaluation of smart-HOP, a hand-off mechanism tailored for low-power wireless networks. This work has three main contributions. First, it formulates the hard hand-off process for low-power networks (such as typical wireless sensor networks - WSNs) with a probabilistic model, to investigate the impact of the most relevant channel parameters through an analytical approach. Second, it confirms the probabilistic model through simulation and further elaborates on the impact of several hand-off parameters. Third, it fine-tunes the most relevant hand-off parameters via an extended set of experiments, in a realistic experimental scenario. The evaluation shows that smart-HOP performs well in the transitional region while achieving more than 98 percent relative delivery ratio and hand-off delays in the order of a few tens of a milliseconds.

  • 12.
    Fotouhi, Hossein
    et al.
    Polytechnic Institute of Porto (ISEP-IPP), Porto, Portugal.
    Zúñiga, Marco
    Polytechnic Institute of Porto (ISEP-IPP), Porto, Portugal.
    Alves, Mário
    Polytechnic Institute of Porto (ISEP-IPP), Porto, Portugal.
    Koubâa, Anis
    Polytechnic Institute of Porto (ISEP-IPP), Porto, Portugal.
    Marrón, Pedro
    Polytechnic Institute of Porto (ISEP-IPP), Porto, Portugal.
    Smart-HOP: A Reliable Handoff Mechanism for Mobile Wireless Sensor Networks2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    Handoff processes, the events where mobile nodes select the best access point available to transfer data, have been well studied in cellular and WiFi networks. However, wireless sensor networks (WSN) pose a new set of challenges due to their simple low-power radio transceivers and constrained resources. This paper proposes smart-HOP, a handoff mechanism tailored for mobile WSN applications. This work provides two important contributions. First, it demonstrates the intrinsic relationship between handoffs and the transitional region. The evaluation shows that handoffs perform the best when operating in the transitional region, as opposed to operating in the more reliable connected region. Second, the results reveal that a proper fine tuning of the parameters, in the transitional region, can reduce handoff delays by two orders of magnitude, from seconds to tens of milliseconds.

  • 13.
    Girs, Svetlana
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Cooperative Communication for Increased Reliability in Industrial Wireless Networks2013Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Introducing wireless networks into distributed industrial systems may enable new or improved application areas and also great cost reductions due to lower complexity of installation and maintenance, compared to existing wired solutions. However, signals travelling through wireless channels are affected by pathloss, fading and shadowing, and, as a result, packet errors are both time-varying and more frequent than in e.g., existing wired fieldbuses. Packet errors or delays occurring in industrial systems can, in critical situations, lead to damage of expensive equipment or even danger to human life. Thus, wireless networks can be accepted for use in industrial networks only when sufficient levels of reliability and timeliness can be guaranteed.

    Relaying is a technique that has the potential to increase reliability with maintained delay. Having different geographical locations, and thus different wireless channel qualities, some nodes may overhear transmitted packets even in cases when the intended receiver did not, and then cooperate by relaying these packets to their final destination.

    This thesis deals with design of relaying strategies aiming to increase reliability in deadline-constrained industrial applications using wireless networks. The influence of several different parameters, such as positions of relay nodes, number of erroneous packets at the relay node and at the destination respectively, as well as the number of available time slots before the deadline, are evaluated to determine the best acting strategy for each relay node. Moreover, it is shown that when a specific relay node has the opportunity to aid more than one source node, performance can be improved even further if the relay node combines several packets, using Luby coding or packet aggregation, and instead relays such combined packets. Given the methods proposed in this thesis, the reliability in industrial wireless networks can be enhanced considerably, without increasing the delay, such that message deadlines still are kept.

  • 14.
    Girs, Svetlana
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Designing a Bandwidth Management Scheme for Heterogeneous Virtualized Networks2018Ingår i: 2018 IEEE 23RD INTERNATIONAL CONFERENCE ON EMERGING TECHNOLOGIES AND FACTORY AUTOMATION (ETFA), IEEE , 2018, s. 1079-1082Konferensbidrag (Refereegranskat)
    Abstract [en]

    With envisioned increased density and complexity of future industrial networks, software defined networking (SDN) and network virtualization are considered to be promising techniques for network organization and management. Thus, in this paper we look at heterogeneous software defined networks consisting of several virtual slices and present a bandwidth control algorithm, which is designed to provide control over shared bandwidth both in wired and wireless parts of the network. The designed algorithm has been implemented in real hardware and in this paper we present the initial test results.

  • 15.
    Girs, Svetlana
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Bergblomma, Marcus
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Uhlemann, Elisabeth
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Halmstad University, Sweden.
    Štimac, Barbara
    University of Zagreb, Zagreb, Croatia .
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Design of Channel Measurement Guidelines for Characterization of Wireless Industrial Environments2013Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Providing reliable and timely communication in wireless industrial systems requires careful design of error control schemes able to tackle the bit error patterns typically occurring in these environments. As most error control schemes target some specific characteristics of a wireless channel, the selection of channel model is crucial for proper performance assessment. There are a number of widely used channel models, but the question of the most appropriate choice of model for industrial environments still remains largely open. Not many indoor measurement campaigns have focused on industrial environments with their own specific characteristics. In this paper we present a set of measurement guidelines aiming to characterize industrial environments such that suitable channel models can be selected to properly evaluate error control schemes targeting reliable and timely wireless communications in industrial environments. 

  • 16.
    Girs, Svetlana
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Uhlemann, Elisabeth
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Halmstad University.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Increased Reliability of Reduced Delay in Wireless Industrial Networks Using Relaying and Luby Codes2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Providing reliable and timely communication in wireless industrial networks is crucial. Previous research has shown that relaying can aid in achieving this goal. We consider the case when relay resources are sparse such that each relay needs to aid e.g., three different sensor nodes and propose to combine relaying with Luby codes. We let the relay node construct a Luby coded packet using the three source packets as input. The destination can then use the Luby coded packet to recover an erroneous or lost source packet regardless of which source that packet belonged to. The performance evaluation shows that our proposed scheme significantly increases the number of correctly received packets before the corresponding deadlines, or alternatively that high reliability can be maintained even if fewer time slots are allocated for retransmissions, thus lowering the delay.

  • 17.
    Girs, Svetlana
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Uhlemann, Elisabeth
    Halmstad University.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik.
    The Effects of Relay Behavior and Position in Wireless Industrial Networks2012Ingår i: 2012 9th IEEE International Workshop on Factory Communication Systems, May 21-24, 2012 Lemgo, Germany: Proceedings, 2012, s. 183-190Konferensbidrag (Refereegranskat)
    Abstract [en]

    In wireless industrial networks, providing reliable and timely communication is crucial. Previous research has shown that relaying can be used to achieve this goal. However, we have found that different types of wireless channels encountered in industrial environments affect the benefits as well as the best behavior and position of relay nodes. We consider two types of behavior: the relay node always retransmits or it only retransmits if it has obtained a correct copy of the packet. We evaluate different positions of the relay node by conducting simulations for two types of fading channels: with and without line of sight. The results clearly show that the benefits, the best behavior and position of a relay node depends on the wireless channel, whether or not the bit errors appear randomly or in bursts and also on the distance between the source and the final destination.

  • 18.
    Girs, Svetlana
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Willig, Andreas
    University of Canterbury, Canterbury, New Zealand.
    Uhlemann, Elisabeth
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Halmstad University, Halmstad, Sweden.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    On the Role of Feedback for Industrial Networks Using Relaying and Packet Aggregation2013Rapport (Övrigt vetenskapligt)
    Abstract [en]

    To be accepted for use in industrial applications, wireless technologies must offer similar performance in terms of reliability and timeliness as provided by current wired solutions. Wireless channels, introducing time-varying packet error rates, impose a significant challenge to fulfill these requirements. One way to improve reliability in industrial wireless networks is to use relaying, whereas packet aggregation is a method that can reduce delay. Hence, in this paper, we propose to use a combination of relaying and packet aggregation. Based on the type of feedback provided by the controller, the relay node can choose the most suitable way to use its allocated time slots such that more packets can reach the controller before their deadlines. The results show that allowing this kind of flexibility at the relay node results in performance improvements. The more flexibility, the greater the gain, and thus further improvements can be made by adjusting the schedule to take different types of feedback into account.

  • 19.
    Gran, Mikael
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Karlsson, Claes
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Survey of VMware NSX Virtualized Network Platform: Utvärdering av VMware NSX Virtualized Network Platform2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Atea Eskilstuna hade behovet av en plattform som kan förenkla och minska antalet konfigurationer vid implementation av kunder. Arbetet gick ut på att utvärdera plattformen VMware NSX och jämföra det mot traditionella nätverkslösningar. I dagens datacenter är virtualisering en viktig del av dess verksamhet. Användandet av virtualisering optimerar hanteringen av hårdvaru-resurser och kostnader. Virtualisering har hittills främst fokuserat på hantering av servrar och klienter, vilket har passerat nätverksutvecklingen, och därför har det uppstått vissa problem med traditionella datacenter gällande trafikflöden, säkerhet och implementering. Datacenter har tidigare varit optimerade för trafik som ska in eller ut ur datacentret. Detta har lett till att brandväggar och säkerhetspolicies ofta placerats vid datacentrets kant. I dagens datacenter har det däremot blivit en ökning på trafik mellan enheter inom datacentret som behöver skyddas. Denna typ av interna säkerhet kan uppnås av interna policies på samtliga nätverksenheter, dock blir det ohållbart vid implementation då antalet konfigurationspunkter i nätverket ökar. Dessa problem kan hanteras med hjälp av VMware NSX som virtualiserar nätverksenheter och centraliserar administration. NSX har en distribuerad brandväggs-funktion vilket medför att policies kan appliceras direkt på virtuella maskiner och virtuella routrar, från en central konfigurationspunkt. Detta ökar säkerheten och minskar implementationstiden jämfört med traditionella datacenter. Arbetet fokuserar på hur NSX arbetar till skillnad från fysiska nätverksenheter samt hur NSX hanterar frågor som trafikflöden, säkerhet och automation. För dessa ändamål byggdes en laborationsmiljö i Ravellos molntjänst med flertalet virtuella maskiner och en litteraturstudie utfördes. Laborationsmiljön användes för att sätta upp kunder med hjälp av virtuella nätverksenheter och virtuella maskiner. Laborationsmiljön användes som referens för hur implementation av NSX och dess funktioner går till. Litteraturstudien fokuserar på vad som är möjligt i NSX och vilka för- och nackdelar som finns med NSX jämfört med traditionella datacenter. Resultaten visade på att den enda nackdelen med NSX var dess licenskostnader.

  • 20.
    Grankvist, Henrik
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Kvarnström, William
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Security Feature Test for Ethernet Switches2014Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    A new standard in network security for industrial control systems is about to be released by a number of working groups within the ISA99 organization. ABB has a certification program for network components that may be used together with the control system 800xA, which is named Industrial IT Certification. ABB now wants to introduce formal testing of network component’s security features according to this standard.The document IEC 62443-4-2 is the document within this standard that describes how the system requirements should be implemented on network components. This document is still a draft, so the document IEC 62443-3-3 which describes how the system requirements should be implemented on a whole industrial control system has been used to estimate the content of IEC 62443-4-2 when it is finished. Out of these two documents the requirements has been broken down into a test description which contains a number of tests to check which security features a switch has and that they work as described. Together with the test description, a test record template has been created to be used for documenting the result from the tests.Finally a comparison was made where the results from a number of different network equipment could be compared against each other regarding their security features. This comparison will in the future make it easier for ABB’s customers when they are in the process of buying new network equipment.In short the more expensive brands of switches have in general more security features implemented, and desktop switches has more security features implemented than industrial switches, with certain exceptions. The buyer needs to ask himself if he really needs all the security features. The choice of what switch to buy all depends on the placement of the switch and what purpose it should fulfill.

  • 21.
    Gutiérrez, Marina
    et al.
    TTTech Computertechnik AG, Austria.
    Steiner, Wilfried
    TTTech Computertechnik AG, Austria.
    Dobrin, Radu
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    A Configuration Agent based on the Time Triggered Paradigm for Real-Time Networks2015Ingår i: IEEE International Workshop on Factory Communication Systems - Proceedings, WFCS, 2015, Vol. Article number 7160584Konferensbidrag (Refereegranskat)
    Abstract [en]

    Distributed cyber-physical systems are growing in size and functionality and deterministic communication is an important requirement for those systems. The existing solutions based on the time-triggered paradigm pose certain limitations in regards to the configuration. Usually configuration is seen as a one-time event during the installation of the network. Future realtime networks need to be able to adapt more easily to changes in the network. Thus, the configuration becomes an ongoing service, e.g., as for network maintenance and re-configuration to add and remove new, respectively old, equipment. We postulate that configuration will emerge to a continued service that accompanies a real-time network throughout its different life-cycle phases. In this context of evolving and dynamic networks, we introduce the concept of a configuration agent for real-time networks and demonstrate the concept by a realization based on the time triggered paradigm.

  • 22.
    Gyllhamn, Claes
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Centraliserad styrning av åtkomstlistor2011Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Can the Danish "Aftalesystemet", a system with the intention to simplify the use of services within health care, be used in Sweden? This project has investigated the possibility by installing and testing the system and explored its functions to detect any eventual problems. Analyses were made of the system's graphical part and the underlying code to see in greater detail how the communication between units occurred, since no actual documentation of it existed. Discussions with the developers took place regarding how the current system works and how further development should continue. In order to test the system, a completely virtual environment was used. Server, clients and routers were virtualized with VirtualBox and GNS3 in order to not disrupt any ongoing services. The results show that because of how the Danish infrastructure is constructed, and how the system is developed to function primarily in a Danish infrastructure, some changes are needed regarding the design of the database, the GUI and the generation of access lists. Because MedCom and Inera are cooperating on this project, some functions will only be available in either language. However, the plan is that the system will be generalized to such a degree in the future that it can be used cooperatively by several countries.

  • 23.
    Henriksson, Johannes
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Magnusson, Alexander
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Impact of using cloud-based SDNcontrollers on the networkperformance2019Självständigt arbete på grundnivå (högskoleexamen), 180 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Software-Defined Networking (SDN) is a network architecture that differs from traditionalnetwork planes. SDN has tree layers: infrastructure, controller, and application. Thegoal of SDN is to simplify management of larger networks by centralizing control into thecontroller layer instead of having it in the infrastructure. Given the known advantages ofSDN networks, and the flexibility of cloud computing. We are interested if this combinationof SDN and cloud services affects network performance, and what affect the cloud providersphysical location have on the network performance. These points are important whenSDN becomes more popular in enterprise networks. This seems like a logical next step inSDN, centralizing branch networks into one cloud-based SDN controller. These questionswere created with a literature studies and answered with an experimentation method. Theexperiments consist of two network topologies both locally hosted SDN (baseline) and cloudhosted SDN. The topology used Zodiac FX switches and Linux hosts. The following metricswas measured: throughput, latency, jitter, packet loss, and time to add new hosts. Theconclusion is that SDN as a cloud service is possible and does not significantly affect networkperformance. One limitation with this thesis was the hardware, resulting in big fluctuationin throughput and packet loss.

  • 24.
    Hoang, Le-Nam
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Uhlemann, Elisabeth
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Jonsson, M.
    School of Information Technology, Halmstad University, Halmstad, Sweden.
    Relay Grouping to Guarantee Timeliness and Reliability in Wireless Networks2019Ingår i: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 23, nr 9, s. 1661-1664, artikel-id 8737952Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Relaying can increase reliability, range, or throughput. In many cyber-physical systems (CPS), relaying is used to maximize reliability before a given deadline. Since concurrent transmissions are not supported by most CPS, time-division multiple access (TDMA) is typically used. However, a major drawback of relaying in TDMA is that pre-allocated time-slots are wasted if their respective transmitters do not have any correctly received packet to relay. Therefore, in this letter, we propose a novel relay grouping scheme to overcome this drawback. Numerical results show that the proposed scheme significantly enhances the reliability while guaranteeing the deadline for each message. 

  • 25.
    Holmstedt, Christoffer
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Model-checked Space Plug-and-Play Architecture Local Subnet Adaptation implemented in Ada with Ravenscar restrictions2014Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Space Plug-and-Play Architecture (SPA) is a set of standards to make it easier to build small satellites. Focus is put on improving the integration phase andthe time consuming validation and verification process by introducing plug-and-play functionality. From mission call-up to operational satellite it should only take six days.

    A SPA network consists of several different types of subnets with differentpros and cons. For each processing node there must be one Local Subnet Manager (SM-L). The SM-L can communicate over different communication protocols depending on how the respective local subnet is set up, one option is UDP/IP.

    In this thesis Ada Protected Objects is presented as a viable option for inter-process communication instead of UDP/IP in a SPA network. This thesis presents the initial work towards a SPA Local Subnet Adaptation that builds onlanguage constructs in Ada such as Ada Tasks and Protected Objects. The system design and implementation is verified deadlock free with UPPAAL but showsindications of livelock possibilities. The severity of these livelocksituations is discussed in the conclusion.

  • 26.
    Li, Ning
    et al.
    Universidad Politecnica de Madrid, Madrid, Spain .
    Cürüklü, Baran
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Bastos, Joaquim
    Instituto de Telecomunicacoes, Lisboa, Portugal .
    Sucasas, Victor
    Universidade de Aveiro, Aveiro, Portugal .
    Fernandez, Jose Antonio Sanchez
    Universidad Politecnica de Madrid, Madrid, Spain .
    Rodriguez, Jonathan
    Campus Universitário de Santiago, Lisboa, Portugal .
    A probabilistic and highly efficient topology control algorithm for underwater cooperating AUV networks2017Ingår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, nr 5, artikel-id 1022Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of the Smart and Networking Underwater Robots in Cooperation Meshes (SWARMs) project is to make autonomous underwater vehicles (AUVs), remote operated vehicles (ROVs) and unmanned surface vehicles (USVs) more accessible and useful. To achieve cooperation and communication between different AUVs, these must be able to exchange messages, so an efficient and reliable communication network is necessary for SWARMs. In order to provide an efficient and reliable communication network for mission execution, one of the important and necessary issues is the topology control of the network of AUVs that are cooperating underwater. However, due to the specific properties of an underwater AUV cooperation network, such as the high mobility of AUVs, large transmission delays, low bandwidth, etc., the traditional topology control algorithms primarily designed for terrestrial wireless sensor networks cannot be used directly in the underwater environment. Moreover, these algorithms, in which the nodes adjust their transmission power once the current transmission power does not equal an optimal one, are costly in an underwater cooperating AUV network. Considering these facts, in this paper, we propose a Probabilistic Topology Control (PTC) algorithm for an underwater cooperating AUV network. In PTC, when the transmission power of an AUV is not equal to the optimal transmission power, then whether the transmission power needs to be adjusted or not will be determined based on the AUV’s parameters. Each AUV determines their own transmission power adjustment probability based on the parameter deviations. The larger the deviation, the higher the transmission power adjustment probability is, and vice versa. For evaluating the performance of PTC, we combine the PTC algorithm with the Fuzzy logic Topology Control (FTC) algorithm and compare the performance of these two algorithms. The simulation results have demonstrated that the PTC is efficient at reducing the transmission power adjustment ratio while improving the network performance.

  • 27.
    Liu, Meng
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Schedulability analysis of GMF-modeled messages over controller area networks with mixed-queues2014Ingår i: IEEE Int. Workshop Factory Commun. Syst. Proc. WFCS, 2014, s. Article number 6837606-Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Controller Area Network (CAN) is widely utilized in many industrial real-time applications. As a real-time communication network, the predictability of timing behaviors is very important. Therefore, many works have been proposed regarding the schedulability analysis of CAN messages. Most of the existing analysis approaches are based on a traditional periodic message model. However, in some applications, the transmission of a message may follow a certain pattern instead of repeating the same transmission period by period. In these cases, applying the existing analysis methods may lead to quite pessimistic results. In order to tackle this problem, in this paper we apply the Generalized Multi-Frame (GMF) task model on CAN messages, where both priority-based and FIFO-based message queues are taken into account. We present a corresponding sufficient schedulability analysis. According to the experimental evaluations, our analysis can provide tighter results compared to the existing CAN message response time analysis in the context of GMF-modeled messages. 

  • 28.
    Ljungberg, Andreas
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Mätningssystem för inbyggda sensorer i hälsoteknik2016Självständigt arbete på grundnivå (kandidatexamen), 180 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Medicinsk personal och har använt ett Go/No-Go test, som ett verktyg för att diagnostisera ADHD (Attention Deficit Hyperactivity Disorder) hos patienter. I testen används en uppsättning av sfärer i olika sekventiella mönster där patienten med hjälp av en tryckknapp markerar när en specifik färg visas på skärmen. Till testet finns en kamera som registrerar patientens rörelser. Problemet med testet är att flera individuella testomgångar och utvärderingar krävs för att urskilja personer med ADHD ifrån personer utan ADHD. Frågan som undersökts är hur och om det är användbart att tillföra ytterligare inbyggda sensorer och bättre analyseringsmjukvara för att förbättra, korta ner och förenkla den nuvarande utvärderingsprocessen.En bakgrundsstudie har utförts för att få fram en bra grund till implementationen och teoretiskt fastställa om systemet är användbart vid diagnostisering av ADHD. Prototypen användes sedan med sensorer av psykologer som fick utvärdera principen. Både teorin och användartesterna framförde tydliga resultat på att flera sensorer och bättre mjukvaruimplementation kommer leda till kortare diagnostiseringsfaser hos patienter med ADHD.

  • 29.
    Loni, Mohammad
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Daneshtalab, Masoud
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Sjödin, Mikael
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    ADONN: Adaptive design of optimized deep neural networks for embedded systems2018Ingår i: Proceedings - 21st Euromicro Conference on Digital System Design, DSD 2018, Institute of Electrical and Electronics Engineers Inc. , 2018, s. 397-404Konferensbidrag (Refereegranskat)
    Abstract [en]

    Nowadays, many modern applications, e.g. autonomous system, and cloud data services need to capture and process a big amount of raw data at runtime that ultimately necessitates a high-performance computing model. Deep Neural Network (DNN) has already revealed its learning capabilities in runtime data processing for modern applications. However, DNNs are becoming more deep sophisticated models for gaining higher accuracy which require a remarkable computing capacity. Considering high-performance cloud infrastructure as a supplier of required computational throughput is often not feasible. Instead, we intend to find a near-sensor processing solution which will lower the need for network bandwidth and increase privacy and power efficiency, as well as guaranteeing worst-case response-times. Toward this goal, we introduce ADONN framework, which aims to automatically design a highly robust DNN architecture for embedded devices as the closest processing unit to the sensors. ADONN adroitly searches the design space to find improved neural architectures. Our proposed framework takes advantage of a multi-objective evolutionary approach, which exploits a pruned design space inspired by a dense architecture. Unlike recent works that mainly have tried to generate highly accurate networks, ADONN also considers the network size factor as the second objective to build a highly optimized network fitting with limited computational resource budgets while delivers comparable accuracy level. In comparison with the best result on CIFAR-10 dataset, a generated network by ADONN presents up to 26.4 compression rate while loses only 4% accuracy. In addition, ADONN maps the generated DNN on the commodity programmable devices including ARM Processor, High-Performance CPU, GPU, and FPGA.

  • 30.
    Maabi, Somayeh
    et al.
    Shahid Beheshti University, Tehran, Iran.
    Safaei, Farshad R.Pour
    Shahid Beheshti University, Tehran, Iran .
    Rezaei, Amin
    University of Louisiana at Lafayette, Lafayette, United States.
    Daneshtalab, Masoud
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Royal Institute of Technology (KTH), Stockholm, Sweden.
    Zhao, Dan
    Old Dominion University, Norfolk, United States .
    ERFAN: Efficient reconfigurable fault-tolerant deflection routing algorithm for 3-D Network-on-Chip2016Ingår i: International System on Chip Conference, IEEE Computer Society, 2016, s. 306-311Konferensbidrag (Refereegranskat)
    Abstract [en]

    With degradation in transistors dimensions and complication of circuits, Three-Dimensional Network-on-Chip (3-D NoC) is presented as a promising solution in electronic industry. By increasing the number of system components on a chip, the probability of failure will increase. Therefore, proposing fault tolerance mechanisms is an important target in emerging technologies. In this paper, two efficient fault-tolerant routing algorithms for 3-D NoC are presented. The presented algorithms have significant improvement in performance parameters, in exchange for small area overhead. Simulation results show that even with the presence of faults, the network latency is decreased in comparison with state-of-the-art works. In addition, the network reliability is improved reasonably.

  • 31.
    Malmgren, Andreas
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Persson, Simon
    Mälardalens högskola, Akademin för innovation, design och teknik.
    A comparative study of Palo Alto Networks and Juniper Networks next-generation firewalls for a small enterprise network2016Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This thesis is a comparative study of two Next-Generation Firewalls (NGFWs) with the aim to conclude which one is the most suitable for a small enterprise network. The network in question is Company A’s Office A1. Office A is in the process of upgrading their internal network and with the upgrade a new NGFW will be implemented. The two NGFW platforms that have been researched per Company A’s request are Juniper Networks’ SRX-series firewalls and Palo Alto Networks’ (PAN) PA-series, with focus on the SRX1500 and PA-3020 for a fair comparison. To be able to evaluate different platforms and appliances, the concept of NGFW and what it constitutes has been researched and presented. Both of the NGFW platforms have been tested and compared in terms of ease-of-use and cost analysis. The testing focused on the respective web-interfaces and shows no significant differences between the two NGFWs at a first glance in terms of functionality. However, PAN’s web-interface does objectively feel more up-to-date and provides application visibility natively, which Juniper offers as a separate service as part of the centralised management platform, which is excessive for Office A’s network. The research and collection of data has been conducted based on Office A’s needs and requirements. Third-party research has been collected from NSS Labs and Gartner and serves as a basis for the evaluation. The future network of Office A introduces new services and the general usage will mainly consist of office oriented application based traffic. The evaluation of the research of the two NGFWs and the collection of data, in the context of Office A’s network, shows that the PA-3020 would be favoured. The key points are as follows:

    • PAN’s NGFWs are built specifically for application awareness whereas Juniper are new in the NGFW market and has recently started to add the more advanced application awareness features.
    • PAN offers a one-box solution suited for smaller networks such as Office A whereas a Juniper implementation would require additional hardware (VM’s) to obtain similar features.
    • PAN offers more features in terms of user identification which is a key factor in enabling a true context aware security environment seamlessly integrated and invisible to the users.

    No major difference in cost if a similar set of features are to be implemented, based on non-rebated list prices (additional hardware not included).

    1 Note: Due to confidentiality, the name and details of the company has been anonymised throughout the report.

  • 32.
    Persson, Anders
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Platform development of body area network for gait symmetry analysis using IMU and UWB technology2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Having a device with the capability of measure motions from gait produced by a human being, could be of most importance in medicine and sports. Physicians or researchers could measure and analyse key features of a person's gait for the purpose of rehabilitation or science, regarding neurological disabilities. Also in sports, professionals and hobbyists could use such a device for improving their technique or prevent injuries when performing. In this master thesis, I present the research of what technology is capable of today, regarding gait analysis devices. The research that was done has then help the development of a suggested standalone hardware sensor node for a Body Area Network, that can support research in gait analysis. Furthermore, several algorithms like for instance UWB Real-Time Location and Dead Reckoning IMU/AHRS algorithms, have been implemented and tested for the purpose of measuring motions and be able to run on the sensor node device. The work in this thesis shows that a IMU sensor have great potentials for generating high rate motion data while performing on a small mobile device. The UWB technology on the other hand, indicates a disappointment in performance regarding the intended application but can still be useful for wireless communication between sensor nodes. The report also points out the importance of using a high performance micro controller for achieving high accuracy in measurements.

  • 33.
    Pozo, Francisco
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Rodriguez-Navas, Guillermo
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Hansson, Hans
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Self-Healing Protocol: Repairing Scheduels Online after Link Failures in Time-Triggered NetworksIngår i: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The time-triggered paradigm is not adaptive, a static schedule determines the time-triggered communication and, then, any unpredicted change, like a link failure, might result in the loss of frames. Using spatial redundancy or recomputing a new schedule for replacement achieves fault tolerance only in moderate-size networks. With the increase in size and complexity of cyber-physical systems, more scalable and cost-efficient mechanisms are needed in order to complement conventional solutions. We propose a distributed Self-Healing Protocol that instead of recomputing the whole schedule, repairs the existent schedule at runtime. The basis of our protocol is the collaboration of nodes in the network to individually adjust their local schedules for rerouting the frames affected by link failures. Our protocol exhibits a high success rate compared to full rescheduling, as well as remarkable scalability; it repairs the schedule in milliseconds, whereas rescheduling requires minutes.

  • 34.
    Pozo Pérez, Francisco Manuel
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Rodriguez-Navas, Guillermo
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Hansson, Hans
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Semi-Distributed Self-Healing Protocol for Online Schedule Repair after Network Failures2019Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Adaptive requirements for networks with strict timing restrictions do challenge the static nature of the time-triggered communication paradigm. Continuous changes in the network topology during operation require frequent rescheduling, followed by schedule distribution, a process that is excessively time-consuming as it was intended to be performed only during the design phase. The fully-distributed Self-Healing Protocol introduced a collaborative method to quickly modify the local schedules of the nodes during runtime, after link failures. This protocol gets the network back to correct operation in milliseconds, but it assumes that only the nodes are able to modify their local schedules, which limited the achieved improvement. This paper proposes to shift to a semi-distributed strategy, where high-performance nodes are responsible for the nodes and links within a small network segment. These nodes rely on their privileged view of the system in order to reduce the response time, increase the healing success rate, and extend the fault model to include switch failures. 

  • 35.
    Sanzogni, L.
    et al.
    Griffith Univ, Nathan, Australia.
    Bonner, Richard
    Griffith Univ, Nathan, Australia.
    Chan, R.
    Griffith Univ, Nathan, Australia.
    Vaccaro, J.A.
    Griffith Univ, Nathan, Australia.
    Perceptrons with polynomial post-processing1996Ingår i: Proceedings of the International Conference on Tools with Artificial Intelligence, 1996, s. 472-474Konferensbidrag (Refereegranskat)
    Abstract [en]

    Introduces tensor-product neural networks, composed of a layer of univariate neurons followed by a net of polynomial post-processing. We look at the general approximation problem by these networks observing in particular their relationship to the Stone-Weierstrass theorem for uniform function algebras. The implementation of the post-processing as a two-layer network with logarithmic and exponential neurons leads to potentially important 'generalised' product networks which, however, require a complex approximation theory of the Müntz-Szasz-Ehrenpreis type. A backpropagation algorithm for product networks is presented and used in three computational experiments. In particular, approximation by a sigmoid product network is compared to that of a single-layer radial basis network and a multiple-layer sigmoid network.

  • 36.
    Sjöberg, Katrin
    et al.
    Högskolan i Halmstad, Inbyggda system (CERES).
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Inbyggda system (CERES).
    Ström, Erik G.
    Chalmers University of Technology.
    How severe is the hidden terminal problem in VANETs when using CSMA and STDMA?2011Ingår i: IEEE Vehicular Technology Conference (VTC Fall) / [ed] IEEE, Piscataway, N.J.: IEEE conference proceedings , 2011, s. 1-5Konferensbidrag (Refereegranskat)
    Abstract [en]

    The hidden terminal problem is often said to be the major limiting performance factor in vehicular ad hoc networks. In this article we propose a definition of the hidden terminal problem suitable for broadcast transmissions and proceed with a case study to find how the packet reception probability is affected by the presence of hidden terminals. Two different medium access control methods; carrier sense multiple access (CSMA) from IEEE 802.11p and self-organizing time division multiple access (STDMA), are subject of investigation through computer simulations of a highway scenario with a Nakagami fading channel model. The results reveal that the presence of hidden terminals does not significantly affect the performance of the two MAC protocols. STDMA shows a higher packet reception probability for all settings due to the synchronized packet transmissions.

  • 37.
    Telander Håkansson, Jonas
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Eriksson, Lennart
    Mälardalens högskola, Akademin för innovation, design och teknik.
    A reliable timing system using RFID2015Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Timing systems for outdoor competitions recently started to use Radio Frequency ID (RFID) technology, to simplify and make precise time registrations of the participants. A couple of application for this usage exists on the market as of today, but none of them has addressed the issue of communication reliability. With a lot of RFID readers placed in different location during a competition, acting as checkpoints and connected to one network and having one computer managing all the registrations, what happens if a cable breaks or a computer crashes? This report describes the thesis work that was conducted mainly in order to address that issue. The goal of the thesis work has been to improve and extend an existing software used for timekeeping by adding new functionality and extending it with the reliability that was requested. A state-of-the-art analyze was made among related work, with focus on intermediate storage and time synchronization, in order to find the most suitable way of securing reliable communication. Software and hardware related to the work was researched, and the problems that needed to be addressed were divided into four research question which were all answered, and presented in this report. The result is a system where an application, implemented in a Raspberry Pi single board computer, helps the existing software to ensure that all the registrations during a competition are at some point sent to the main computer and subsequently stored in the competition database, even if the communication is temporarily broken.

  • 38.
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Inbyggda system (CERES).
    Report on Wireless Vehicular Communications: [VTS News]2012Ingår i: IEEE Vehicular Technology Magazine, ISSN 1556-6072, E-ISSN 1556-6080, Vol. 7, nr 3, s. 102-106Artikel i tidskrift (Övrigt vetenskapligt)
  • 39.
    Urama, Ifeoma Helen
    et al.
    Mälardalens högskola.
    Fotouhi, Hossein
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Abdellatif, M. M.
    British University in Egypt, Cairo, Egypt.
    Optimizing RPL Objective Function for Mobile Low-Power Wireless Networks2017Ingår i: Proceedings - International Computer Software and Applications Conference, IEEE Computer Society , 2017, s. 678-683Konferensbidrag (Refereegranskat)
    Abstract [en]

    Supporting mobility in wireless sensor networks is one of the major requirements for future Internet of Things (IoT) applications. This work focuses on optimizing the objective function of Routing Protocol for Low-power and Lossy Networks (RPL) in mobile applications. RPL routing is the most common standard routing protocol designed for IoT applications. We optimized RPL objective function by combining several RPL parameters, such as (i) Expected Transmission Count (ETX), (ii) number of hops, and (iii) average Received Signal Strength Indicator (RSSI) as inputs in a fuzzy logic model. These parameters are more influenced in mobile applications. We applied the fuzzy decision to the mRPL (a hand-off enabled RPL mechanism). We fine-tuned the weighting scheme by running extensive simulations to achieve reliable data communication. We found that the fuzzy-based hand-off approach provides high reliability by successfully delivering nearly 100% of data packets, while achieving a very short hand-off delay. 

  • 40.
    Vo, Van Nhan
    et al.
    Duy Tan Univ, Danang, Vietnam.
    Tran, Hung Vinh
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Uhlemann, Elisabeth
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Truong, Quach Xuan
    VNU Univ Engn & Technol, Hanoi, Vietnam.
    So-In, Chakchai
    Khonkaen Univ, Appl Network Technol ANT Lab, Khon Kaen, Thailand..
    Balador, Ali
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Reliable Communication Performance for Energy Harvesting Wireless Sensor Networks2019Ingår i: 2019 IEEE 89TH VEHICULAR TECHNOLOGY CONFERENCE (VTC2019-SPRING), IEEE , 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we study the problem of how to provide reliable communications for energy harvesting (EH) wireless sensor network (WSN). Using the example of an autonomous quarry, where self-driving trucks autonomously collect and transport goods, there is a need for multiple wireless sensors collecting data about where and when goods can be collected, while guaranteeing reliable operation of the quarry. The vehicles transfer energy to the wireless sensors within range, forming a cluster. The sensors use this energy to transmit data to the vehicles. Finally, the vehicles relay information to an access point (AP). The AP processes the collected information and synchronize the operation of all vehicles. We propose an interference channel selection policy for the sensors-to-vehicles links and vehicles-to-AP links to improve the reliability of the communications, while enhancing the energy utilization. Accordingly, closed-form expression on how to achieve reliable communication within the considered system is derived and numerical results show that the proposed channel selection strategy not only improves the probability of achieving sufficiently reliable communication but also enhances the energy utilization.

  • 41.
    Wang, W.
    et al.
    Computer Science Department, University of Pittsburgh, Pittsburgh, PA, United States.
    Mosse, D.
    Computer Science Department, University of Pittsburgh, Pittsburgh, PA, United States.
    Papadopoulos, Alessandro
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Packet priority assignment for wireless control systems of multiple physical systems2019Ingår i: Proceedings - 2019 IEEE 22nd International Symposium on Real-Time Distributed Computing, ISORC 2019, Institute of Electrical and Electronics Engineers Inc. , 2019, s. 143-150Konferensbidrag (Refereegranskat)
    Abstract [en]

    Wireless control systems (WCSs) have gained much attention lately, due to their easy deployment and flexibility compared to wired control systems. However, this comes at the cost of possibly increased network delay and packet losses, that can significantly impact the control system performance, and possibly its stability. Such problems become even more relevant if the network is shared among different control systems, and thus becomes a scarce resource, like in Industrial Internet of Things applications. In this paper, we describe how to assign packet priorities dynamically when there are many physical systems sharing a given network, aiming at minimizing the performance degradation of the WCS. Towards that, we present a network model including both delay and packet losses, both of which are very important for the control system performance. Our solution is evaluated over two different use cases to show the generality of the approach: the WCS for a set of inverted pendula, and the WCS for small modular reactors in a nuclear power plant. The results show that the proposed approach allows for a more stable performance even in presence of highly nonlinear systems, sensitive to time-varying delays, as well as in presence of high network interference.

  • 42.
    Westermark, Antti
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Pantzar, David
    Mälardalens högskola, Akademin för innovation, design och teknik.
    UTVECKLING AV KOMBINERAD DATAKOMMUNIKATION OCH TWO WAY RANGING FÖR IEEE 802.15.4 ULTRAWIDEBANDSYSTEM2019Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Trådlös kommunikation mellan noder sker genom att skicka data över det trådlösa mediet, för att få kommunikationen att samspela har flertalet standarder utvecklats. En av dessa standarder är 802.15.4 med UWB PHY vars utformning är av en sådan karaktär att signalöverföringen blir störningstålig och osynlig för andra standarder. UWB används ofta till lokalisering och positionering, men kan även användas till en samtida dataöverföring då standardens utformning tillåter detta. Det var dock oklart med vilken prestanda detta kunde genomföras. Därför har den datakommunikationsprestandan undersöks. Den hypotes som följdes under arbetet var att ''genom att skicka data mellan positioneringsimpulserna möjliggörs användandet av samma enhet för positionering och datakommunikation, systemets prestanda påverkas då av MAC-metoden''. Ur hypotesen kom det tre frågeställningar: Vilken MAC-metod är lämplig för både positionering och dataöverföring? Är det möjligt att använda systemet för både positionering och dataöverföring genom att skicka data mellan positioneringsimpulserna? Vilken kommunikationsprestanda kan uppnås när systemet används för både postionering och dataöverföring? I arbetet bevisas hypotesen samt frågeställningarna med syftet att detta kunde komma att hjälpa till inom exempelvis robotiken, men även som ett alternativ till WiFi då UWB är både störningståligt och osynligt för andra standarder. Den iterativa metoden användes för att utveckla ett system som kunde lösa den kombinerade positioneringen och datakommunikationen. I prestandatesterna gick det att utläsa att hypotesen stämde förutsatt att parametrarna är korrekt.

  • 43.
    Willig, Andreas
    et al.
    University of Canterbury, Christchurch, New Zealand.
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Inbyggda system (CERES).
    Deadline-Aware Scheduling of Cooperative Relayers in TDMA-Based Wireless Industrial Networks2014Ingår i: Wireless networks, ISSN 1022-0038, E-ISSN 1572-8196, Vol. 20, nr 1, s. 73-88Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper we consider a scenario in which a set of source nodes wishes to transmit real-time data packets periodically to a central controller over lossy wireless links, while using a TDMA-based medium access control protocol. Furthermore, a number of relay nodes are present which can help the source nodes with packet retransmissions. The key question we consider in this paper is how to schedule the TDMA slots for retransmissions while taking advantage of the relay nodes, so that the average number of packets missing their deadlines is minimized. We provide a problem formulation for the general deadline-aware TDMA relay scheduling problem. Since the design space of the general problem is large, we also present one particular class of restricted TDMA relay scheduling problems. We suggest and numerically investigate a range of algorithms and heuristics, both optimal and suboptimal, of the restricted scheduling problem, which represent different trade-offs between achievable performance and computational complexity. Specifically, we introduce two different Markov Decision Process (MDP) based formulations for schedule computation of the restricted TDMA relay scheduling problem. One MDP formulation gives an optimal schedule, another (approximate) formulation gives a sub-optimal schedule which, however, comes very close to the optimal performance at much more modest computational and memory costs.

  • 44.
    Willig, Andreas
    et al.
    University of Canterbury.
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Inbyggda system (CERES).
    On relaying for wireless industrial communications: Is careful placement of relayers strictly necessary?2012Ingår i: IEEE International Workshop on Factory Communication Systems, 2012, s. 191-200Konferensbidrag (Refereegranskat)
    Abstract [en]

    Relaying is a very promising technique to improve the reliability of data transmission in wireless (industrial) networks. With relaying, relay nodes support source nodes in carrying out retransmissions. A common assumption is that relayers should be placed at “good” positions (e.g. in the middle between source and destination) to achieve benefits. In this paper we tackle the question of whether it is strictly necessary to place relayers at “good” positions (which often requires extensive measurements). We present results indicating that the benefits of relaying are achievable even with randomly placed relayers, as long as enough of them are deployed. Specifically, we present results suggesting that with a sufficient (and still not too high) number of randomly deployed relayers, the probability that all packets, sent by source nodes to a central controller in a TDMA round, reach the controller is larger than for the case with source-only retransmissions. This finding holds true both in the absence and the presence of feedback.

  • 45.
    Yu, Kan
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    On Reliable and Deadline-Constrained Communication in Wireless Industrial Networks2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Along with the quick development of wireless communication technologies, industrial automation networks are also in unceasing evolution. Industrial wireless sensor and actuator networks (IWSAN) have been increasingly adopted in industrial automation systems. Although there are a number of advantages of replacing cables with wireless links, such as cost reduction, enhanced scalability and flexibility, the stringent requirements on communication reliability and meeting firm deadlines from industrial mission-critical applications must still be fulfilled. Also, transmissions over wireless channels in industrial environments are prone to noise and interferences, resulting in frequent erroneous packet deliveries. Although industrial automation systems are usually designed to be tolerant of certain communication errors, successive transmission failures may still cause downtime of industrial applications, which might lead to significant economic losses or even serious accidents. This thesis addresses the problems mentioned above and aims to provide reliable and deadline-constrained communication via IWSANs for industrial automation systems. On the MAC layer, existing IWSAN standards utilize automatic repeat request (ARQ) to improve reliability at the cost of additional transmission latency. An alternative method is to use Forward Error Correction (FEC) schemes to provide reliable communication by recovering erroneous data and avoiding unnecessary retransmissions. On the MAC layer, Time Division Multiple Access (TDMA) is usually applied in current IWSAN standards for collision-free and deterministic communication. An inappropriate scheduling scheme may introduce high transmission jitter and degrade the quality of control. On the network layer, routing protocols play an important role in both communication reliability and latency. Existing solutions are either hardly able to fulfill all stringent requirements from the mission-critical industrial applications, too complicated to be realized, or lack verification in reality. The contributions of this thesis consist of (i) the possibilities of using FEC schemes in IWSANs is explored under the requirements of existing standards on the MAC layer. A compatible and flexible FEC scheme on the MAC layer for IWSANs that does not violate the standard is proposed and evaluated by simulations. (ii) To guarantee an acceptable control quality, a TDMA scheduling scheme is presented aiming for low communication jitter, and it is compared to classic scheduling schemes. (iii) The advantages of exploiting flooding in IWSANs is discussed; a reliable controlled flooding-based routing protocol is proposed and compared to both traditional routing protocols and other flooding-based protocols. (iv) A complete IWSAN platform is built and the whole protocol stack is implemented. Measurements were conducted in a real industrial environment to verify the correctness of the proposed solution.

  • 46.
    Yu, Kan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    On Reliable Real Time Communication in Industrial Wireless Sensor Networks2012Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    In the industrial automation, Industrial Wireless Sensor Networks (IWSNs) have been increasingly applied due to a great number of benefits such as convenient installation, flexible deployment and cost efficiency. Compared with conventional wireless systems, IWSNs have more stringent requirements communication reliability and real time performance. However, IWSNs are frequently deployed in a hash industrial environment with electromagnetic disturbances, moving objects and non-line-of-sight (NLOS) communication. Because of the vulnerability of wireless signal, IWSNs are under high risk oftransmission failures, which may result in missing or delaying of process orcontrol data. For industrial automation, missing the process or control deadlineis intolerable, which may terminate industrial application and finally result in economic loss and safety problems. From hierarchy point of view, the high communication reliability and low communication latency can be achieved from different network layers. OnMAC layer, existing protocols in IWSNs only provide automatic repeat request (ARQ) to improve reliability at the cost of real time performance. Analternative method is to apply Forward Error Correction (FEC) mechanism on MAC layer to provide more reliable transmissions and reduce acknowledgement messages by recovering error data. On network layer, routing protocolplays an important role in both communication reliability and latency. Traditionalrouting protocols in IWSNs are either hardly able to fulfill both of these requirements or overcomplicated.In this thesis, we initially explore the possibilities of introducing FEC intoIWSN under the requirements of the existing standard on MAC layer. Then we propose compatible and flexible FEC schemes on MAC layer for IWSNs without violating the standard format. Routing protocols based on flooding are proved to increase the Packet Delivery Ratio (PDR) by transmission diversity.We propose reliable and robust routing protocols with respect to high reliability and real time performance for IWSNs.

  • 47.
    Yu, Kan
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Barac, Filip
    Mid Sweden University.
    Gidlund, Mikael
    ABB, Corporate Research.
    Åkerberg, Johan
    ABB, Corporate Research.
    Adaptive Forward Error Correction for Best Effort Wireless Sensor Networks2012Ingår i: 2012 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC), 2012, s. 7104-7109Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this work we propose an Adaptive Forward Error Correction (AFEC) algorithm for best effort Wireless Sensor Networks. The switching model is described in terms of a finite-state Markov model and it is based on the channel behavior,observed via Packet Delivery Ratio in the recent past. We compare the performance of AFEC with static FEC, as well as uncoded transmissions. The results demonstrate a gain in PDR achieved by introducing FEC coding in uncoded IEEE 802.15.4 transmissions, as well as the advantages over static FEC schemes,namely increased throughput and reduced energy consumption.The proposed solution is IEEE 802.15.4-compliant and requires no additional feedback channels.

  • 48.
    Yu, Kan
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Filip, Barac
    Mid Sweden University.
    Mikael, Gidlund
    ABB, Corporate Research.
    Åkerberg, Johan
    ABB, Corporate Research.
    Mats, Björkman
    Mälardalens högskola, Akademin för innovation, design och teknik.
    A Flexible Error Correction Scheme for IEEE 802.15.4-based Industrial Wireless Sensor Networks2012Ingår i: IEEE International Symposium on Industrial Electronics, 2012, s. 1172-1177Konferensbidrag (Refereegranskat)
    Abstract [en]

    Noise and interference make a substantial impacton wireless transmissions in industrial environments, resulting infrequent erroneous packet deliveries. Existing industrial communication standards adopt the IEEE 802.15.4 specification, which provides no means to correct the detected errors. We propose an IEEE 802.15.4-compliant Forward Error Correction-basedapproach that can be easily retrofitted into the standard withoutthe need for any kind of interaction with chip manufacturers orstandardization bodies. We evaluate the approach on link- and network-level scenarios. Improvement of reliability by using FEC can yield multiple benefits: a reduced number of retransmissions,and lower average latency, to name a few. With respect to the uncoded system, the proposed solution provides identical codinggain as the traditional FEC method, at a significantly lower computational load of decoding.

  • 49.
    Yu, Kan
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Gidlund, Mikael
    ABB, Corporate Research.
    Åkerberg, Johan
    ABB, Corporate Research.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Reliable and Low Latency Transmission in Industrial Wireless Sensor Networks2011Ingår i: Procedia Computer Science, ISSN 1877-0509, E-ISSN 1877-0509, Vol. 5, s. 866-873Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The major advantages with Industrial Wireless Sensor Networks (IWSNs) in process automation are cable cost reduction, enhanced flexibility and enabling new emerging applications such as wireless control. However, transmission over the wireless channel is prone to noise and interference which causes packets to be erroneous received at the receiver node. To improve the link reliability in lossy channels, error correcting codes are commonly used. In this paper we discuss the use of forward error correction (FEC) codes in IWSN in order not only to improve the link reliability but also to reduce the number of retransmissions in harsh industrial environments. We propose a FEC scheme suitable for MAC level protection where the packet is divided into groups and encoded using systematic FEC codes. We have implemented different FEC codes in a typical IWSN chip to evaluate memory consumption and to ensure that we are not violating the strict timing rules for acknowledgment. Our results show that some FEC codes are suitable to be implemented in a typical IWSN node while several fails due to large memory footprint or to long encoding and decoding time.

  • 50.
    Yu, Kan
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Gidlund, Mikael
    ABB, Corporate Research.
    Åkerberg, Johan
    ABB, Corporate Research.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Reliable RSS-based Routing Protocol for Industrial Wireless Sensor Networks2012Ingår i: IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society: Proceeding, 2012, s. 3231-3237Konferensbidrag (Refereegranskat)
    Abstract [en]

    High reliability and real-time performance are main research challenges in Industrial Wireless Sensor Networks (IWSNs). Existing routing protocols applied in IWSNs are either overcomplicated or fail to fulfill the stringent requirements. In this paper, we propose a reliable and flexible Received Signal Strength-based routing scheme. Our proposed solution can achieve a seamless transition in the event of topology change and can be applied in different industrial environments. The simulation results show that our solution outperforms conventional routing protocols in both reliability and latency. Furthermore, the result also proves that the changes of the network topology have no impact on data transmissions of other nodes by our scheme, whereas conventional routing protocols are shown to fail to recover the network in a short time. Finally, due to dynamic weighting mechanism, the proposed scheme is verified to achieve significantly higher reliability in scenarios with obstacles and avoid installation troubles, compared to location-based flooding scheme. Thus, our proposed scheme is considered to be more suitable for IWSNs than other routing protocols.

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