65 research outputs found
Design of a multi-agent system for distributed voltage regulation
In this paper, an intelligent distributed multi-agent system (MAS) is proposed for the implementation of a novel optimization technique for distributed voltage regulation. The proposed MAS approach controls a large heavily-meshed distribution network which is grouped into small subnetworks using Δ decomposition. The voltage regulation is accomplished by distributed generator (DG) agents, linear programming solver (LPS) agents, network violation detector (NVD) agents, and one Δ decomposition agent. The LPS agent has an embedded control algorithm which optimizes DG generation within a subnetwork once the voltage at particular nodes exceeds the normal operational limits. The subnetworks and their control requirements are achieved through self-organization, which is the novelty of the research. Each intelligent agent has its own knowledge and reasoning logic to plan its own activities. The control actions are coordinated through agent communications within the subnetwork. The agent platform, Presage2, with improved autonomy and agent communication capability, has been used to develop the proposed MAS system and design the agentsâ behaviors
Simultaneous evolutionary expansion and constraint of genomic heterogeneity in multifocal lung cancer.
Recent genomic analyses have revealed substantial tumor heterogeneity across various cancers. However, it remains unclear whether and how genomic heterogeneity is constrained during tumor evolution. Here, we sequence a unique cohort of multiple synchronous lung cancers (MSLCs) to determine the relative diversity and uniformity of genetic drivers upon identical germline and environmental background. We find that each multicentric primary tumor harbors distinct oncogenic alterations, including novel mutations that are experimentally demonstrated to be functional and therapeutically targetable. However, functional studies show a strikingly constrained tumorigenic pathway underlying heterogeneous genetic variants. These results suggest that although the mutation-specific routes that cells take during oncogenesis are stochastic, genetic trajectories may be constrained by selection for functional convergence on key signaling pathways. Our findings highlight the robust evolutionary pressures that simultaneously shape the expansion and constraint of genomic diversity, a principle that holds important implications for understanding tumor evolution and optimizing therapeutic strategies.Across cancer types tumor heterogeneity has been observed, but how this relates to tumor evolution is unclear. Here, the authors sequence multiple synchronous lung cancers, highlighting the evolutionary pressures that simultaneously shape the expansion and constraint of genomic heterogeneity
Supporting Control Room Operators in Highly Automated Future Power Networks
Operating power systems is an extremely challenging task, not least because power systems have become highly interconnected, as well as the range of network issues that can occur. It is therefore a necessity to develop decision support systems and visualisation that can effectively support the human operators for decision-making in the complex and dynamic environment of future highly automated power system. This paper aims to investigate the decision support functions associated with frequency deviation events for the proposed Web of Cells concept
Demonstration of visualization techniques for the control room engineer in 2030.:ELECTRA Deliverable D8.1. WP8: Future Control Room Functionality
Deliverable 8.1 reports results on analytics and visualizations of real time flexibility in support of voltage and frequency control in 2030+ power system. The investigation is carried out by means of relevant control room scenarios in order to derive the appropriate analytics needed for each specific network event
A self-organizing multi-agent system for distributed voltage regulation
This paper presents a distributed voltage regulation method based on multi-agent system control and network self-organization for a large distribution network. The network autonomously organizes itself into small subnetworks through the epsilon decomposition of the sensitivity matrix, and agents group themselves into these subnetworks with the communication links being autonomously determined. Each subnetwork controls its voltage by locating the closest local distributed generation and optimizing their outputs. This simplifies and reduces the size of the optimization problem and the interaction requirements. This approach also facilitates adaptive grouping of the network by self-reorganizing to maintain a stable state in response to time-varying network requirements and changes. The effectiveness of the proposed approach is validated through simulations on a model of a real heavily-meshed secondary distribution network. Simulation results and comparisons with other methods demonstrate the ability of the subnetworks to autonomously and independently regulate the voltage and to adapt to unpredictable network conditions over time, thereby enabling autonomous and flexible distribution networks
Peripheral Blood Lymphocyte Subsets Predict the Efficacy of Immune Checkpoint Inhibitors in NonâSmall Cell Lung Cancer
BackgroundNonâsmall cell lung cancer (NSCLC) has entered the era of immunotherapy. However, only partial patients were able to benefit from immune checkpoint inhibitors (ICIs). Currently, biomarkers for predicting patientsâ response to ICIs are primarily tumor tissue dependent and have limited accuracy. There is an urgent need to explore peripheral blood-based biomarkers to predict the efficacy and safety of ICI therapy.MethodsTo explore the correlation between lymphocyte subsets and the efficacy and safety of ICIs, we retrospectively analyzed peripheral blood lymphocyte subsets and survival prognosis data of 136 patients with stage IV NSCLC treated with ICIs.ResultsThe two factors that had the greatest impact on the prognosis of patients with NSCLC treated with ICIs were CD4+CD45RAâ T cell (HR = 0.644, P = 0.047) and CD8+ T/lymphocyte (%) (HR = 1.806, P = 0.015). CD4+CD45RAâ T cell showed excellent predictive efficacy (AUC = 0.854) for ICIs monotherapy, with a sensitivity of 75.0% and specificity of 91.7% using CD4+CD45RAâ T cell >311.3 Ă 106/L as the threshold. In contrast, CD8+ T/lymphocyte (%) was only associated with the prognosis but had no predictive role for ICI efficacy. CD4+ T cell and its subsets were significantly higher in patients with mild (grades 1â2) immune-related adverse events (irAEs) than those without irAEs. CD8+CD38+ T cell was associated with total irAEs and severe (grades 3â4) irAEs but was not suitable to be a predictive biomarker.ConclusionPeripheral blood CD4+CD45RAâ T cell was associated with the prognosis of patients with NSCLC applying ICIs, whereas CD8+CD38+ T cell was associated with irAEs and severe irAEs
Hybrid iterative algorithm for finite families of countable Bregman quasi-Lipschitz mappings with applications in Banach spaces
A multi-agent system design and implementation for flexible network management
Strathclyde theses - ask staff. Thesis no. : T14887With the introduction of renewable energy technologies to reduce greenhouse gas emissions, a significant amount of Distributed Generation (DG) has connected to distribution networks. Hence, the operation of electrical power distribution systems has become complicated and increasingly challenging due to the uncertainty of bi-directional power flow, voltage fluctuations, and frequency deviations. To help manage these issues, the system requires more intelligent functions and flexibility in order to support solutions for network management and operation. Moreover, distribution network operators are looking for an active approach to maximise the utilisation of network capacity while solving network issues for more DG connections. As a result, Active Network Management (ANM) has been proposed to facilitate DG connections without breaching network operation limits. This is achieved by managing network control functions in line with operational objectives and it is often seen as a way to avoiding the high costs of reinforcing the existing infrastructure. However, as the network continues to change, such as increasing DG connections, and control functions keep evolving overtime. ANM is considered to be part of the solution for at least the medium term.;ANM is considered to be part of the solution for at least the medium term. Therefore, ANM requires sufficient flexibility to adapt changes to its environment and extensibility to upgrade control functions overtime for future needs. A key aspect of this is interoperability to allow ANM to interact with different control devices, such as intelligent electronic devices, to collect data and realise control purposes as they also evolve.Multi-agent Systems (MAS) is one of the most relevant technologies to address the above challenges as it provides autonomous and proactive behaviour in open and dynamic environments, which is analogous to new DG connections. In addition, MAS offers a flexible and extensible platform that is the advantage of other relevant technologies, such as a service-oriented architecture. Therefore, it is proposed as part of the work of this thesis that the requirement for flexibility and extensibility can be achieved through the development of control functions as intelligent agents with scalable capabilities brought about through the use of MAS technology. The novel solver agent developed as part of the work of this thesis is an essentialcomponent of the MAS architecture considered in this thesis incorporates an integrated control algorithm and negotiation capability to solve conflicts between various control solutions.;This thesis presents a fully integrated MAS architecture for ANM. It is developed by following a comprehensive design methodology and each stage of the proposed MAS architecture is detailed through specification to implementation. Selected control algorithms are developed as intelligent agents to achieve multiple ANM solutions. In order to provide a common understanding of terminology for agent communications, ontologies for power system control applications, including thermal overload and voltage violation, have been created. A novel IEC 61850 interface has been developed and embedded inside the agent to address interoperability issue between devices for data collection and control.;To evaluate the performance of the developed MAS architecture, along with the novel elements of this thesis a range of simulation case studies are explored. Studies are based on a closed-loop simulation environment with a power system simulator: one case study is based on an operational UK 11 kV radial distribution network to demonstrate the application of MAS for various power system controls; another examines the self-organising ability of the developed MAS architecture by using the Δ decomposition algorithm for distributed voltage regulation. The results demonstrate the flexibility, extensibility, and self-organisation capabilities of the novel fully integrated MAS architecture. This is built upon and the prospects for the inclusion of the MAS technology within operational power systems is discussed and recommendations made as part of this thesis.With the introduction of renewable energy technologies to reduce greenhouse gas emissions, a significant amount of Distributed Generation (DG) has connected to distribution networks. Hence, the operation of electrical power distribution systems has become complicated and increasingly challenging due to the uncertainty of bi-directional power flow, voltage fluctuations, and frequency deviations. To help manage these issues, the system requires more intelligent functions and flexibility in order to support solutions for network management and operation. Moreover, distribution network operators are looking for an active approach to maximise the utilisation of network capacity while solving network issues for more DG connections. As a result, Active Network Management (ANM) has been proposed to facilitate DG connections without breaching network operation limits. This is achieved by managing network control functions in line with operational objectives and it is often seen as a way to avoiding the high costs of reinforcing the existing infrastructure. However, as the network continues to change, such as increasing DG connections, and control functions keep evolving overtime. ANM is considered to be part of the solution for at least the medium term.;ANM is considered to be part of the solution for at least the medium term. Therefore, ANM requires sufficient flexibility to adapt changes to its environment and extensibility to upgrade control functions overtime for future needs. A key aspect of this is interoperability to allow ANM to interact with different control devices, such as intelligent electronic devices, to collect data and realise control purposes as they also evolve.Multi-agent Systems (MAS) is one of the most relevant technologies to address the above challenges as it provides autonomous and proactive behaviour in open and dynamic environments, which is analogous to new DG connections. In addition, MAS offers a flexible and extensible platform that is the advantage of other relevant technologies, such as a service-oriented architecture. Therefore, it is proposed as part of the work of this thesis that the requirement for flexibility and extensibility can be achieved through the development of control functions as intelligent agents with scalable capabilities brought about through the use of MAS technology. The novel solver agent developed as part of the work of this thesis is an essentialcomponent of the MAS architecture considered in this thesis incorporates an integrated control algorithm and negotiation capability to solve conflicts between various control solutions.;This thesis presents a fully integrated MAS architecture for ANM. It is developed by following a comprehensive design methodology and each stage of the proposed MAS architecture is detailed through specification to implementation. Selected control algorithms are developed as intelligent agents to achieve multiple ANM solutions. In order to provide a common understanding of terminology for agent communications, ontologies for power system control applications, including thermal overload and voltage violation, have been created. A novel IEC 61850 interface has been developed and embedded inside the agent to address interoperability issue between devices for data collection and control.;To evaluate the performance of the developed MAS architecture, along with the novel elements of this thesis a range of simulation case studies are explored. Studies are based on a closed-loop simulation environment with a power system simulator: one case study is based on an operational UK 11 kV radial distribution network to demonstrate the application of MAS for various power system controls; another examines the self-organising ability of the developed MAS architecture by using the Δ decomposition algorithm for distributed voltage regulation. The results demonstrate the flexibility, extensibility, and self-organisation capabilities of the novel fully integrated MAS architecture. This is built upon and the prospects for the inclusion of the MAS technology within operational power systems is discussed and recommendations made as part of this thesis
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