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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Performance Analysis and Improvement of 5G based Mission Critical Motion Control Applications

Bhimavarapu, Koushik January 2022 (has links)
The industrial needs in the production of goods and control of processes within the factory keep leapfrogging daily by the necessities to fulfil the needs of the ever-growing population. In recent times, the industries are looking towards Industry 4.0 to improve their overall productivity and scalability. One of the significant aspects that are required to meet the requirements of Industry 4.0 is communication networks among industrial applications. Nowadays, industries from the cross markets are looking to replace their existing wired networks with wireless networks, which indeed brings many use-cases and a lot of new business models into existence. To make all these options possible, wireless networks need to meet the stringent requirements of these industrial applications in the form of reliability, latency, and service availability. This thesis focuses on a systematic methodology to integrate wireless networks like 5G, Wi-Fi 6, etc., into real-life automation devices. It also describes a methodology to evaluate their communication and control performance by varying control parameters like topology, cycle time, and type of networks. It also devises some techniques and methods that can improve the overall performance, i.e., both control and communication performance of the control applications. The method used to implement this work is a case study. This work integrates and tests the industrial applications in a real-life scenario. It is the best effort to bring a unique perspective of communication engineers and control engineers together regarding the performance of the industrial applications. This work tries to verify the suitability of the wireless in mission-critical control application scenarios with respect to their communication and control performance. Software for data analysis and visualization and its methodology for analyzing the traffic flow of the control applications via different wireless networks is demonstrated by varying different control parameters. It is shown that it is challenging for 5G to support the shorter cycle time values, and performance will get better and more stable with the increase in the cycle time of the control application. It is also found that the 1-Hop wireless topologies have a comparatively better control performance than 2-Hop wireless topologies. In the end, it is found that the communication and control performance of the motion control application can be improved by using the hybrid topology, which is a mixture of 5G and Wi-Fi 6, by modifying some key aspects. The thesis work helps to introduce a novel systematic methodology for measuring and analyzing the communication and control applications via different wireless networks. It also gives a better idea for the control engineers in the industry about which cycle times the different wireless networks and their topologies support when integrated with industrial automation devices. It also describes which wireless networks support industrial applications better. It ends with a novel methodology that could improve the performance of the mission-critical motion applications by using existing wireless technologies.
22

Dynamic Assessment in Foreign Language Individualized Instruction

LEE, SOO YUN 28 December 2016 (has links)
No description available.
23

GAME THEORETICAL MODELS OF COMPETITION IN TIME-SENSITIVE MARKETS

Bakhtiari, Behrouz 04 1900 (has links)
<p>This study focuses mainly on situations of time-based competition. Three problems in this context will be studied in three different parts. In the first part, we will examine the promised delivery time (PDT) competition for firms whose production processes consist of more than one stage. We study three games; a) when each firm consists of two stages and has identical production rates in both stages, b) when each firm consists of k stages and has identical production rate in all stages and, c) when each firm consists of two stages and has different production rates in each stage. In the second part, we focus on a duopolistic market where the firms compete against each other by determining their PDT. The firms try to win the business of a single customer who is sensitive to PDT but will also penalize the winning firm through tardiness costs. This situation may emerge when the production duration is too long and the product is expensive as in the aviation industry. The third part of this study deals with situations of investment competition in the presence of incomplete information in the market. The investment decision will affect the time to production (speed) and determines the probability of winning the business. The notion of incompleteness in information is projected when firms are not fully certain about each other's objective function. In each chapter, we will find the equilibrium of the game and determine the players' optimal strategies. At the end of each chapter, a numerical analysis is presented, where numerous numerical examples are solved. Based on the numerical examples, a sensitivity analysis is also presented for each model that would capture the sensitivity of the Nash equilibria and the firms' optimal strategies towards changes in parameters in the market or the competitor's operations.</p> / Doctor of Philosophy (PhD)
24

Time-Sensitive Networking in Digital Substations

Johansson, Andreas, Wågbrant, Samuel January 2024 (has links)
With the advancements in the Industrial Internet of Things (IIoT), new networking requirements and demands are introduced to Substation Automation Systems (SAS) within electrical power grids. The possibility of merging Information Technology (IT) and Operational Technology (OT) traffic on the same network to achieve higher productivity, however, presents new challenges in providing real-time guarantees to OT traffic. Time-Sensitive Networking (TSN) can be a promising solution that allows IT and OT traffic to coexist seamlessly while still providing real-time guarantees for critical applications. Substations act as critical nodes within power grids, and their digitalisation is a crucial element in the energy transition. A digital substation handles International Electrotechnical Commission (IEC) 61850 protocol traffic such as Generic Object Oriented Substation Event (GOOSE), Sampled Values (SV), and Manufacturing Message Specification (MMS), which all have strict timing requirements. The integration of TSN into these substations could improve the handling of this traffic and, consequently, the controllability of power grids. This thesis investigates the use of TSN in an IEC 61850 process bus, typically implemented in an SAS. A series of simulated test scenarios were developed to evaluate the impact of TSN compared to traditional networking methods. These included configurations using Ethernet, Ethernet with priority queuing, and TSN with Time-Aware Shaper (TAS) and Credit-Based Shaper (CBS). The results indicate that TSN can meet critical timing requirements, reduce jitter, and manage sporadic traffic effectively under high traffic loads. While the TAS scheduler may increase End-to-End delay for periodic traffic, CBS can reduce it for event-based traffic. Furthermore, robust timing guarantees are ensured for the TSN scenarios by providing a feasible schedule for Scheduled Traffic (ST) and a worst-case response time analysis for Audio-Video Bridging (AVB) traffic. This research highlights TSN’s potential to improve grid controllability and reliability through enhanced network performance, illustrating its role in the future of resilient grid technologies.
25

Security Analysis of OPC UA in Automation Systems for IIoT / Säkerhetsanalys av OPC UA inom automationssystem för IIoT.

Varadarajan, Vaishnavi January 2022 (has links)
Establishing secured communication among the different entities in an industrial environment is a major concern. Especially with the introduction of the Industrial Internet of Things (IIoT), industries have been susceptible to cyber threats, which makes security a critical requirement for the industries. Prevailing industrial communication standards were proven to meet the security needs to some extent, but the major issue which was yet to be addressed was interoperability. To achieve interoperability, Open Platform Communication Unified Architecture (OPC UA) was introduced as a communication protocol. OPC UA helped bridge the gap between Information Technology (IT) and Operational Technology (OT) security needs, but this also gives rise to new attack opportunities for the intruder. In this thesis, we have analysed the security challenges in OPC UA and the impact of two different cyberattacks on the OPC UA. First, we have implemented an OPC UA Network with the help of Raspberry Pis and open62541, an open-source implementation of the OPC UA client and server. Following this, to evaluate the performance of the network, we performed three cybersecurity attacks, Packet Sniffing, Man in the Middle Attack (MITM) and Denial of Service attack. We assessed the impact these attacks have on the OPC UA network. We have also discussed the detection mechanism for the same attacks. This analysis has helped us recognize the threats faced by OPC UA in an IIoT environment with respect to message flooding, packet sniffing and man in the middle attack and the countermeasures to this attack have been discussed / Att etablera en säker kommunikation mellan de olika enheterna i en industriell miljö är en stor utmaning. Speciellt efter introduktionen av Industrial Internet of Things (IIoT) har industrier varit mottagliga för cyberhot vilket gör cybersäkerhet en prioritet. Rådande industriella kommunikationsstandarder har visats att till viss del uppfylla säkerhets- behoven, men en av de största problemen var bristen på interoperabilitet. För att uppnå interoperabiliteten skapades Open Platform Communication Unified Architecture (OPC UA) som kommun- ikationsprotokoll. OPC UA hjälper till att överbrygga gapet mellan säkerhetsbehoven av information- steknologi (IT) och Operational Technology (OT), men detta ger också upphov till nya attackmöjligheter för inkräktare. I detta examensarbete har vi analyserat säkerhetsutmaningarna i OPC UA och effekten av två olika cyberattacker på OPC UA. Först har vi implementerat ett OPC UA Network med hjälp av Raspberry Pis och open62541 som är en öppen källkodsimplementering av OPC UA klient och server. Efter detta utförde vi tre cybersäkerhetsattacker för att utvärdera nätverkets prestanda, packet sniffing, Man in the Middle Attack (MITM) och Denial of Service attack. Vi bedömde vilken effekt dessa attacker har på OPC UA-nätverket. Vi har också diskuterat detektionsmekanismen för samma attacker. Denna analys har hjälpt oss att känna igen de hot som OPC UA står inför i en IIoT-miljö med avseende på dataflöde, packet sniffing och Man in the Middle attack och även försvar mot dessa attacker har diskuterats.
26

Security Analysis of OPC UA in Automation Systems for IIoT / Säkerhetsanalys av OPC UA inom automationssystem för IIoT.

Varadarajan, Vaishnavi January 2022 (has links)
Establishing secured communication among the different entities in an industrial environment is a major concern. Especially with the introduction of the Industrial Internet of Things (IIoT), industries have been susceptible to cyber threats, which makes security a critical requirement for the industries. Prevailing industrial communication standards were proven to meet the security needs to some extent, but the major issue which was yet to be addressed was interoperability. To achieve interoperability, Open Platform Communication Unified Architecture (OPC UA) was introduced as a communication protocol. OPC UA helped bridge the gap between Information Technology (IT) and Operational Technology (OT) security needs, but this also gives rise to new attack opportunities for the intruder. In this thesis, we have analysed the security challenges in OPC UA and the impact of two different cyberattacks on the OPCUA. First, we have implemented an OPC UA Network with the help of Raspberry Pis and open62541, an open-source implementation of the OPC UA client and server. Following this, to evaluate the performance of the network, we performed three cybersecurity attacks, Packet Sniffing, Man in the Middle Attack (MITM) and Denial of Service attack. We assessed the impact these attacks have on the OPC UA network. We have also discussed the detection mechanism for the same attacks. This analysis has helped us recognize the threats faced by OPC UA in an IIoT environment with respect to message flooding, packet sniffing and man in the middle attack and the countermeasures to this attack have been discussed. / Att etablera en säker kommunikation mellan de olika enheterna i en industriell miljö är en stor utmaning. Speciellt efter introduktionen av Industrial Internet of Things (IIoT) har industrier varit mottagliga för cyberhot vilket gör cybersäkerhet en prioritet. Rådande industriella kommunikationsstandarder har visats att till viss del uppfylla säkerhets- behoven, men en av de största problemen var bristen på interoperabilitet. För att uppnå interoperabiliteten skapades Open Platform Communication Unified Architecture (OPC UA) som kommun- ikationsprotokoll. OPC UA hjälper till att överbrygga gapet mellan säkerhetsbehoven av information- steknologi (IT) och Operational Technology (OT), men detta ger också upphov till nya attackmöjligheter för inkräktare. I detta examensarbete har vi analyserat säkerhetsutmaningarna i OPC UA och effekten av två olika cyberattacker på OPC UA. Först har vi implementerat ett OPC UA Network med hjälp av Raspberry Pis och open62541 som är en öppen källkodsimplementering av OPC UA klient och server. Efter detta utförde vi tre cybersäkerhetsattacker för att utvärdera nätverkets prestanda, packet sniffing, Man in the Middle Attack (MITM) och Denial of Service attack. Vi bedömde vilken effekt dessa attacker har på OPC UA-nätverket. Vi har också diskuterat detektionsmekanismen för samma attacker. Denna analys har hjälpt oss att känna igen de hot som OPC UA står inför i en IIoT-miljö med avseende på dataflöde, packet sniffing och Man in the Middle attack och även försvar mot dessa attacker har diskuterats.
27

Wise by Design: A Wisdom-Based Framework for Innovation and Organizational Design and its Potential Application in the Future of Higher Education

Suarez, Juan F. 01 June 2014 (has links)
No description available.

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