275 research outputs found
A New Economic Dispatch for Coupled Transmission and Active Distribution Networks Via Hierarchical Communication Structure
Traditionally, the economic dispatch problem (EDP) of the bulk generators connected to transmission networks (TNs) is solved in a centralized dispatching center (CDC) while modeling distribution networks as passive loads. With the increasing penetration levels of distributed generation, coordinating the economic dispatch between TNs and active distribution networks (ADNs) became vital to maximizing system efficiency. This article proposes a hierarchical communication structure, which requires minimal upgrades to the CDC, for solving the EDP of coupled TNs and ADNs. Based on the minimal data transfer between the CDC and distribution network operators, the problem is formulated and solved while considering the network losses in both TNs and ADNs. Furthermore, a sensitivity analysis is conducted to assess the effect of the ratio of the distribution lines on the economic dispatch solution and the operational cost of the system. The numerical results demonstrate the effectiveness of the proposed centralized scheme and highlight the significance of considering the network losses of both TNs and ADNs when solving the EDP. The results show that the proposed framework can achieve savings of up to 17.98% by taking into account the network losses of TNs and ADNs
Microfluidic Communications Protocol Design and Transmission Performance Analysis
The new field of nanocommunications aims to develop communication systems at the nanoscale. It has developed into two main communication directions: molecular communications andelectromagnetic communications. Microfluidic communications is a subtype of molecular communications. Existing liquid based microfluidics applications are the main target for the integration of a communication feature.
Currently, there are still no standards for microfluidics communications protocol. The protocols should consider particular phenomena such as noise, transmission access priorities, and probability of coalescence between microdroplets. Those phenomena bring challenges in protocol development of microfluidics communications.
In this thesis, the protocol stack for microfluidics communications is developed. Starting from the physical layer, feasible modulation schemes for data transmission suitable for microfluidics communications is examined. Later, medium access control layer protocols is discussed in order to optimize transmission medium access for the network entities. This is done to avoid droplet coalescence. Specification of the addressing and routing methods is defined to ensure data submission to the destination point. Finally, the performance of the proposed schemes and numerical comparison to viable alternatives are analyzed.
The results of the evaluation are reached through MATLAB software simulations. This work concentrates on Communication through Silence (CtS) where the payload is represented as distance between two droplets. Two schemes of CtS (decimal and hexadeximal) are investigated. Both CtS schemes with particular optimum amount binary payload outperforms OOK in throughput performance. The fairness of the transmission system can be achieved for a decentralized system by combining slotted (TDMA) scheme and a probability-based algorithm
Innovative Concepts and Applications for Smart Water Cities
Smart cities are emerging worldwide, including economic, institutional, social, and technical concepts in interaction with existing infrastructure to achieve sustainability and increase quality of life. Additionally, digitalisation projects in the field of urban water infrastructure (UWI) aim to increase capacity of existing infrastructure to deal with future challenges caused by climate change, growing of urban population, and maintenance. Therefore, efficient and reliable information- and communication technologies (ICT) represent a key factor for the exchange of measurement data (e.g., monitoring environmental parameters) and interconnections between different participants. However, ICT and system-wide management are not yet widely deployed and mainly concentrated on main points in network-based UWI (e.g., combined sewer overflows, inlet point of district meter areas). In this context, especially the Internet of Things (IoT) concepts enables a large-scale implementation of measurement devices even at underground and remote structures, increasing data availability significantly. Following, new possibilities in the management of network-based UWI are emerging. The research aim of this doctoral dissertation is to contribute to the ongoing development of smart water cities by developing innovative concepts in the field of urban drainage and water distribution network including nature-based solutions
Recommended from our members
Converged IP-over-standard ethernet progress control networks for hydrocarbon process automation applications controllers
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The maturity level of Internet Protocol (IP) and the emergence of standard Ethernet interfaces of Hydrocarbon Process Automation Application (HPAA) present a real opportunity to combine independent industrial applications onto an integrated IP based network platform. Quality of Service (QoS) for IP over Ethernet has the strength to regulate traffic mix and support timely delivery. The combinations of these technologies lend themselves to provide a platform to support HPAA applications across Local Area Network (LAN) and Wide Area Network (WAN) networks. HPAA systems are composed of sensors, actuators, and logic solvers networked together to form independent control system network platforms. They support hydrocarbon plants operating under critical conditions that — if not controlled — could become dangerous to people, assets and the environment. This demands high speed networking which is triggered by the need to capture data with higher frequency rate at a finer granularity. Nevertheless, existing HPAA network infrastructure is based on unique autonomous systems, which has resulted in multiple, parallel and separate networks with limited interconnectivity supporting different functions. This created increased complexity in integrating various applications and resulted higher costs in the technology life cycle total ownership. To date, the concept of consolidating HPAA into a converged IP network over standard Ethernet has not yet been explored. This research aims to explore and develop the HPAA Process Control Systems (PCS) in a Converged Internet Protocol (CIP) using experimental and simulated networks case studies. Results from experimental and simulation work showed encouraging outcomes and provided a good argument for supporting the co-existence of HPAA and non-HPAA applications taking into consideration timeliness and reliability requirements. This was achieved by invoking priority based scheduling with the highest priority being awarded to PCS among other supported services such as voice, multimedia streams and other applications. HPAA can benefit from utilizing CIP over Ethernet by reducing the number of interdependent HPAA PCS networks to a single uniform and standard network. In addition, this integrated infrastructure offers a platform for additional support services such as multimedia streaming, voice, and data. This network‐based model manifests itself to be integrated with remote control system platform capabilities at the end user's desktop independent of space and time resulting in the concept of plant virtualization
Data analytics for stochastic control and prognostics in cyber-physical systems
In this dissertation, several novel cyber fault diagnosis and prognosis and defense methodologies for cyber-physical systems have been proposed. First, a novel routing scheme for wireless mesh network is proposed. An effective capacity estimation for P2P and E2E path is designed to guarantee the vital transmission safety. This scheme can ensure a high quality of service (QoS) under imperfect network condition, even cyber attacks. Then, the imperfection, uncertainties, and dynamics in the cyberspace are considered both in system model and controller design. A PDF identifier is proposed to capture the time-varying delays and its distribution. With the modification of traditional stochastic optimal control using PDF of delays, the assumption of full knowledge of network imperfection in priori is relaxed. This proposed controller is considered a novel resilience control strategy for cyber fault diagnosis and prognosis. After that, we turn to the development of a general framework for cyber fault diagnosis and prognosis schemes for CPSs wherein the cyberspace performance affect the physical system and vice versa. A novel cyber fault diagnosis scheme is proposed. It is capable of detecting cyber fault by monitoring the probability of delays. Also, the isolation of cyber and physical system fault is achieved with cooperating with the traditional observer based physical system fault detection. Next, a novel cyber fault prognosis scheme, which can detect and estimate cyber fault and its negative effects on system performance ahead of time, is proposed. Moreover, soft and hard cyber faults are isolated depending on whether potential threats on system stability is predicted. Finally, one-class SVM is employed to classify healthy and erroneous delays. Then, another cyber fault prognosis based on OCSVM is proposed --Abstract, page iv
Accelerating Audio Data Analysis with In-Network Computing
Digital transformation will experience massive connections and massive data handling. This will imply a growing demand for computing in communication networks due to network softwarization. Moreover, digital transformation will host very sensitive verticals, requiring high end-to-end reliability and low latency. Accordingly, the emerging concept “in-network computing” has been arising. This means integrating the network communications with computing and also performing computations on the transport path of the network. This can be used to deliver actionable information directly to end users instead of raw data.
However, this change of paradigm to in-network computing raises disruptive challenges to the current communication networks. In-network computing (i) expects the network to host general-purpose softwarized network functions and (ii) encourages the packet payload to be modified. Yet, today’s networks are designed to focus on packet forwarding functions, and packet payloads should not be touched in the forwarding path, under the current end-to-end transport mechanisms. This dissertation presents fullstack in-network computing solutions, jointly designed from network and computing perspectives to accelerate data analysis applications, specifically for acoustic data analysis.
In the computing domain, two design paradigms of computational logic, namely progressive computing and traffic filtering, are proposed in this dissertation for data reconstruction and feature extraction tasks. Two widely used practical use cases, Blind Source Separation (BSS) and anomaly detection, are selected to demonstrate the design of computing modules for data reconstruction and feature extraction tasks in the in-network computing scheme, respectively. Following these two design paradigms of progressive computing and traffic filtering, this dissertation designs two computing modules: progressive ICA (pICA) and You only hear once (Yoho) for BSS and anomaly detection, respectively. These lightweight computing modules can cooperatively perform computational tasks along the forwarding path. In this way, computational virtual functions can be introduced into the network, addressing the first challenge mentioned above, namely that the network should be able to host general-purpose softwarized network functions. In this dissertation, quantitative simulations have shown that the computing time of pICA and Yoho in in-network computing scenarios is significantly reduced, since pICA and Yoho are performed, simultaneously with the data forwarding. At the same time, pICA guarantees the same computing accuracy, and Yoho’s computing accuracy is improved.
Furthermore, this dissertation proposes a stateful transport module in the network domain to support in-network computing under the end-to-end transport architecture. The stateful transport module extends the IP packet header, so that network packets carry message-related metadata (message-based packaging). Additionally, the forwarding layer of the network device is optimized to be able to process the packet payload based on the computational state (state-based transport component). The second challenge posed by in-network computing has been tackled by supporting the modification of packet payloads.
The two computational modules mentioned above and the stateful transport module form the designed in-network computing solutions. By merging pICA and Yoho with the stateful transport module, respectively, two emulation systems, i.e., in-network pICA and in-network Yoho, have been implemented in the Communication Networks Emulator (ComNetsEmu). Through quantitative emulations, the experimental results showed that in-network pICA accelerates the overall service time of BSS by up to 32.18%. On the other hand, using in-network Yoho accelerates the overall service time of anomaly detection by a maximum of 30.51%. These are promising results for the design and actual realization of future communication networks
NASA/ASEE Summer Faculty Fellowship Program: 1988 research reports
This contractor's report contains all sixteen final reports prepared by the participants in the 1988 Summer Faculty Fellowship Program. Reports describe research projects on a number of topics including controlled environments, robotics, cryogenic propellant storage, polymers, hydroponic culture, adaptive servocontrol, and computer aided desig
Powerline communication and demand side management for microgrids
Motivation: The greatest challenge for microgrid deployment is making energy affordable, especially in remote low-income communities. This thesis answers the following research question:
Can digital communication reduce the price of electricity for an islanded low voltage microgrid and if so, can broadband powerline communications meet microgrid control requirements?
Approach: This study conducts a cost-benefit analysis of the addition of a field area network to a microgrid. Broadband powerline communication is selected as a candidate technology and tested on various microgrid networks to determine its suitability.
Results: The main contributions of this study are:
A demand-side management strategy and unsubsidised cost reflective tariff structure for rural microgrids in the developing world.
A cost-benefit analysis that shows the addition of a low bit rate, medium latency communication system (1 kbps per customer, 100 ms) may reduce the levelized cost of energy by 32%.
A performance evaluation of broadband HomePlug powerline communications for microgrids which shows the Homeplug AV2 has a range of 600 m and functions well on complex radial distribution networks.
Conclusion: Investment in a minimally capable communication system has significant economic benefit to both customer and utility by enabling smart grid services such as automatic meter reading and demand side management. Since communication technologies share similar bit rate and latency capabilities and are similarly priced, the technology choice is driven more by microgrid geography, complexity, availability and reliability. Powerline communications require no additional cable, but boast reliability similar to dedicated cable solutions. The
HomePlug AV meets bit rate and latency requirements, is affordable, reliable, simple and widely available around the world. This study concludes it is a solid candidate for low voltage islanded microgrids.
The material presented in this thesis has been published or submitted for publication in an abbreviated format in the following publications:
D. Neal et al, "Demand side energy management and customer behavioral response in a rural islanded microgrid," in IEEE PES/IAS PowerAfrica, 2020.
D. Neal, D. Rogers and M. McCulloch, "A Techno-Economic Analysis of Communication in Islanded Microgrids," unpublished. Submitted Oct 2023 to Elsevier Renewable and Sustainable Energy Reviews.
D. Neal, D. Rogers and M. McCulloch, "Broadband Powerline Communication for Low-Voltage Microgrids," unpublished. Submitted Oct 2023 to IEEE Transactions on Power Delivery
- …