scholarly journals Packet Flow Capacity Autonomous Operation Based on Reinforcement Learning

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8306
Author(s):  
Sima Barzegar ◽  
Marc Ruiz ◽  
Luis Velasco

As the dynamicity of the traffic increases, the need for self-network operation becomes more evident. One of the solutions that might bring cost savings to network operators is the dynamic capacity management of large packet flows, especially in the context of packet over optical networks. Machine Learning, particularly Reinforcement Learning, seems to be an enabler for autonomicity as a result of its inherent capacity to learn from experience. However, precisely because of that, RL methods might not be able to provide the required performance (e.g., delay, packet loss, and capacity overprovisioning) when managing the capacity of packet flows, until they learn the optimal policy. In view of that, we propose a management lifecycle with three phases: (i) a self-tuned threshold-based approach operating just after the packet flow is set up and until enough data on the traffic characteristics are available; (ii) an RL operation based on models pre-trained with a generic traffic profile; and (iii) an RL operation with models trained for real traffic. Exhaustive simulation results confirm the poor performance of RL algorithms until the optimal policy is learnt and when traffic characteristics change over time, which prevents deploying such methods in operators’ networks. In contrast, the proposed lifecycle outperforms benchmarking approaches, achieving noticeable performance from the beginning of operation while showing robustness against traffic changes.

Electronics ◽  
2021 ◽  
Vol 10 (13) ◽  
pp. 1515
Author(s):  
Maciej Sobieraj ◽  
Piotr Zwierzykowski ◽  
Erich Leitgeb

DWDM networks make use of optical switching networks that allow light waves of multiple lengths to be serviced and provide the possibility of converting them appropriately. Research work on optical switching networks focuses on two main areas of interest: new non-blocking structures for optical switching networks and finding traffic characteristics of switching networks of the structures that are already well known. In practical design of switching nodes in optical networks, in many cases, the Clos switching networks are successfully used. Clos switching networks are also used in Elastic Optical Networks that can effectively manage allocation of resources to individual multi-service traffic streams. The research outcomes presented in this article deal with the problems of finding traffic characteristics in blocking optical switching networks with known structures. This article aims at presenting an analysis of the influence of traffic management threshold mechanisms on the traffic characteristics of multi-service blocking Clos switching networks that are used in the nodes of elastic optical networks as well as their influence on the traffic efficiency of network nodes. The analysis was carried out on the basis of research studies performed in a specially dedicated purpose-made simulation environment. The article presents a description of the simulation environment used in the experiments. The study was focused on the influence of the threshold mechanism, which is one of the most commonly used and elastic traffic management mechanisms, and on the traffic characteristics of switching networks that service different mixtures of multi-service Erlang, Engset and Pascal traffic streams. The conducted study validates the operational effectiveness and practicality of the application of the threshold mechanism to model traffic characteristics of nodes in an elastic optical network.


Entropy ◽  
2021 ◽  
Vol 23 (6) ◽  
pp. 737
Author(s):  
Fengjie Sun ◽  
Xianchang Wang ◽  
Rui Zhang

An Unmanned Aerial Vehicle (UAV) can greatly reduce manpower in the agricultural plant protection such as watering, sowing, and pesticide spraying. It is essential to develop a Decision-making Support System (DSS) for UAVs to help them choose the correct action in states according to the policy. In an unknown environment, the method of formulating rules for UAVs to help them choose actions is not applicable, and it is a feasible solution to obtain the optimal policy through reinforcement learning. However, experiments show that the existing reinforcement learning algorithms cannot get the optimal policy for a UAV in the agricultural plant protection environment. In this work we propose an improved Q-learning algorithm based on similar state matching, and we prove theoretically that there has a greater probability for UAV choosing the optimal action according to the policy learned by the algorithm we proposed than the classic Q-learning algorithm in the agricultural plant protection environment. This proposed algorithm is implemented and tested on datasets that are evenly distributed based on real UAV parameters and real farm information. The performance evaluation of the algorithm is discussed in detail. Experimental results show that the algorithm we proposed can efficiently learn the optimal policy for UAVs in the agricultural plant protection environment.


2021 ◽  
Author(s):  
Yunfan Su

Vehicular ad hoc network (VANET) is a promising technique that improves traffic safety and transportation efficiency and provides a comfortable driving experience. However, due to the rapid growth of applications that demand channel resources, efficient channel allocation schemes are required to utilize the performance of the vehicular networks. In this thesis, two Reinforcement learning (RL)-based channel allocation methods are proposed for a cognitive enabled VANET environment to maximize a long-term average system reward. First, we present a model-based dynamic programming method, which requires the calculations of the transition probabilities and time intervals between decision epochs. After obtaining the transition probabilities and time intervals, a relative value iteration (RVI) algorithm is used to find the asymptotically optimal policy. Then, we propose a model-free reinforcement learning method, in which we employ an agent to interact with the environment iteratively and learn from the feedback to approximate the optimal policy. Simulation results show that our reinforcement learning method can acquire a similar performance to that of the dynamic programming while both outperform the greedy method.


2021 ◽  
Author(s):  
Yunfan Su

Vehicular ad hoc network (VANET) is a promising technique that improves traffic safety and transportation efficiency and provides a comfortable driving experience. However, due to the rapid growth of applications that demand channel resources, efficient channel allocation schemes are required to utilize the performance of the vehicular networks. In this thesis, two Reinforcement learning (RL)-based channel allocation methods are proposed for a cognitive enabled VANET environment to maximize a long-term average system reward. First, we present a model-based dynamic programming method, which requires the calculations of the transition probabilities and time intervals between decision epochs. After obtaining the transition probabilities and time intervals, a relative value iteration (RVI) algorithm is used to find the asymptotically optimal policy. Then, we propose a model-free reinforcement learning method, in which we employ an agent to interact with the environment iteratively and learn from the feedback to approximate the optimal policy. Simulation results show that our reinforcement learning method can acquire a similar performance to that of the dynamic programming while both outperform the greedy method.


Author(s):  
Anastasios Valkanis ◽  
Georgia Beletsioti ◽  
Petros Nicopolitidis ◽  
Georgios Papadimitriou ◽  
Emmanouel Varvarigos

2021 ◽  
Author(s):  
Lihao Liu ◽  
Shan Yin ◽  
Chen Yang ◽  
Wei Zhang ◽  
Zhenhao Wang ◽  
...  

Author(s):  
Philip Odonkor ◽  
Kemper Lewis

Abstract In the wake of increasing proliferation of renewable energy and distributed energy resources (DERs), grid designers and operators alike are faced with several emerging challenges in curbing allocative grid inefficiencies and maintaining operational stability. One such challenge relates to the increased price volatility within real-time electricity markets, a result of the inherent intermittency of renewable energy. With this challenge, however, comes heightened economic interest in exploiting the arbitrage potential of price volatility towards demand-side energy cost savings. To this end, this paper aims to maximize the arbitrage value of electricity through the optimal design of control strategies for DERs. Formulated as an arbitrage maximization problem using design optimization, and solved using reinforcement learning, the proposed approach is applied towards shared DERs within multi-building residential clusters. We demonstrate its feasibility across three unique building cluster demand profiles, observing notable energy cost reductions over baseline values. This highlights a capability for generalized learning across multiple building clusters and the ability to design efficient arbitrage policies towards energy cost minimization. Finally, the approach is shown to be computationally tractable, designing efficient strategies in approximately 5 hours of training over a simulation time horizon of 1 month.


2019 ◽  
Vol 28 (20) ◽  
pp. 1326-1330 ◽  
Author(s):  
Sharon Ferdinandus ◽  
Lindsay K Smith ◽  
Hemant Pandit ◽  
Martin H Stone

This article provides an overview of the set up for an arthroplasty care practitioner (ACP)-led virtual orthopaedic clinic (VOC). Suitable patients attend a local hospital for an X-ray and complete a questionnaire, but do not physically attend a clinic. This has been running successfully in a university teaching hospital and has led to cost savings, a reduction in outpatient waiting times and high levels of patient satisfaction. Similar clinics have the potential to become normal practice across the NHS. This article outlines the steps necessary to implement a successful VOC. The lessons learnt during this exercise may be useful for other ACPs when setting up a VOC.


2012 ◽  
Vol 30 (4_suppl) ◽  
pp. 194-194
Author(s):  
Krzysztof Krzemieniecki ◽  
Krzysztof Simon ◽  
Krzysztof Zieniewicz ◽  
Pawel Pecilo

194 Background: Due to chronic hepatitis and cirrhosis as main risk factors of HCC – patients in Poland can be treated either by oncologists or by gastroenterologists. As no data exist on HCC patient flow between these specialities, this registry was set up. We also wanted to know the differences in both specialities’ approach to targeted therapies. Methods: Data of patients treated by oncologists (LIVER 2) and gastroenterologists (LIVER 1) were recorded. Descriptive statistical methods and U-Mann-Whitney and Fisher tests were used. Results: 478 patients were included into registry from 2009 until the end of 2010. 70% of patients were male. In 42% cases HCC was caused by HCV and in 24% by HBV. LIVER 2 recorded more patients with unknown HCC aetiology than LIVER 1 (35% vs 15%). The HCC diagnosis was made based on CT scan (80%, ns), US scan (74% in LIVER 1 vs 47% in LIVER 2, p<0,0001) or biopsy (72% LIVER 2 vs 48% LIVER 1, p<0,0001). Patients with advanced stage of HCC according to BCLC scale and poor performance status were more frequently seen by oncologists (LIVER 2), similar prevalence in Child Pugh status was observed in both groups (p<0,05 for all). Registry showed differences in frequency of extrahepatic lesions (10% LIVER 1 42% in LIVER 2, p<0,05). Most common co morbidities were diabetes (32%), liver disorders (39%), hypertension (61%), coronary disease (24%). Median AFP level was 100 ng/ml in LIVER 1 and 219 in LIVER 2 (p=0,057). Registry showed that for gastroenterologists reasons to consider sorafenib as next step in therapy was in 47% cases HCC progression, in 51% good performance status and in 55% sorafenib was found as the only one therapy suitable due to contraindications for other treatments. Oncologists consider sorafenib therapy in 56% cases due to HCC progression and in 72% cases due to good performance status. Among patients considered for targeted therapy, approximately 20% presented Child Pugh B status. Conclusions: This is the first detailed HCC registry in Poland covering the different therapeutic area specialists. Patients with more advanced HCC and worse performance status are more frequently treated by oncologists (p<0,05). The data shows need of early HCC detection interdisciplinary system referring patients to the oncologist.


Sign in / Sign up

Export Citation Format

Share Document