scholarly journals Packet Loss Measurement Based on Sampled Flow

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2149
Author(s):  
Haoliang Lan ◽  
Jie Xu ◽  
Qun Wang ◽  
Wei Ding
Keyword(s):  
Real Time ◽  
Packet Loss ◽  
Access Network ◽  
Packet Losses ◽  
Monitoring Point ◽  
Loss Measurement ◽  
Proposed Model ◽  
Comparison Results ◽  
Before And After ◽  
Network Boundary

This paper is devoted to further strengthening, in the current asymmetric information environment, the informed level of operators about network performance. Specifically, in view of the burst and perishability of a packet loss event, to better meet the real-time requirements of current high-speed backbone performance monitoring, a model for Packet Loss Measurement at the access network boundary Based on Sampled Flow (PLMBSF) is presented in this paper under the premise of both cost and real-time. The model overcomes problems such as the inability of previous estimation to distinguish between packet losses before and after the monitoring point, deployment difficulties and cooperative operation consistency. Drawing support from the Mathis equation and regression analysis, the measurement for packet losses before and after the monitoring point can be realized when using only the sampled flows generated by the access network boundary equipment. The comparison results with the trace-based passive packet loss measurement show that although the proposed model is easily affected by factors such as flow length, loss rate, sampling rate, the overall accuracy is still within the acceptable range. In addition, the proposed model PLMBSF, compared with the trace-based loss measurement is only different in the input data granularity. Therefore, PLMBSF and its advantages are also applicable to aggregated traffic.

Quality Analysis of VoIP in Real-Time Interactive Systems over Lossy Networks

2015 ◽  
pp. 261-274
Author(s):  
Maha Z. Mouasher ◽  
Ala' F. Khalifeh
Keyword(s):  
Real Time ◽  
Packet Loss ◽  
Interactive Systems ◽  
Quality Analysis ◽  
The Internet ◽  
Test Bed ◽  
Lossy Networks ◽  
Packet Losses ◽  
Perceptual Evaluation ◽  
Voice Packets

Voice over Internet Protocol (VoIP) systems have been spreading massively during the recent years. However, many challenges are still facing this technology among which is the lossy behavior and the uncontrolled network impairments of the Internet. In this chapter, the authors design and implement a VoIP test-bed utilizing the Adobe Real-Time Media Flow Protocol (RTMFP) that can be used for many voice interactive applications. The test-bed was used to study the effect of changing some voice parameters, mainly the encoding rate and the number of frames per packet as function of the network packet loss. Several experiments were conducted on several voice files over different packet losses, concluding in the best combination of parameters in low, moderate, and high packet loss conditions to improve the performance of voice packets measured by the Perceptual Evaluation of Speech Quality (PESQ) values.

Control Strategies for Distributed Real-Time Control With Time Delays and Packets Losses

2004 ◽  
Author(s):  
Kun Ji ◽  
Ajit Ambike ◽  
Won-Jong Kim
Keyword(s):  
Time Delay ◽  
Real Time ◽  
Packet Loss ◽  
Time Delays ◽  
Open Loop ◽  
Current Control ◽  
Test Bed ◽  
Real Time Control ◽  
Packet Losses ◽  
Time Operation

Investigation on using network for distributed systems is an important topic in the motion control industry. This paper presents solutions to time-delay and packet-loss problems encountered in distributed real-time operation of an open-loop unstable magnetic levitation (maglev) test bed via an Ethernet. A novel model predictive control strategy with optimal controller design is developed to overcome the adverse influences of time delays and packet losses. By using the prediction of system states and the event-driven and time-driven smart actuator simultaneously, the plant receives the current control signal in every sampling interval even at the presence of time delays and packet losses. Thus we can compensate the time-delay and packet-loss in a uniform way. The simulation and experimental results demonstrated the feasibility and effectiveness of this control algorithm for NCSs with long stochastic time delays and successive packet losses.

Integration effects of UAVs in non-segregated airspace

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Tamer Savas ◽  
Oznur Usanmaz ◽  
Ozlem Sahin ◽  
Ertan Çınar ◽  
Murat Karaderili
Keyword(s):  
Real Time ◽  
Simulation Method ◽  
Flight Time ◽  
Flight Distance ◽  
Content Type ◽  
Time Simulation ◽  
Proposed Model ◽  
Comparison Results ◽  
Quantitative Results ◽  
Real Time Simulations

Purpose The study aims to design a new route model for unmanned aerial vehicles (UAVs) to integrate them into non-segregated airspace. Design/methodology/approach The proposed route model was assessed and validated through real-time simulations. Findings The comparison results of baseline and proposed route model show that a reduction of 38% and 41% in the total flight time and total flight distance were obtained in favour of the proposed model, respectively. Practical implications The proposed route model can be applied by airspace designers and UAV users to perform safe and efficient landing in non-segregated airspace. Originality/value In this study, a new proposed route model is constructed for UAVs. Quantitative results, using a real-time simulation method, are achieved in terms of flight distance and flight time.

scholarly journals A Model for Video Quality Assessment Considering Packet Loss for Broadcast Digital Television Coded in H.264

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Jose Joskowicz ◽  
Rafael Sotelo
Keyword(s):  
Packet Loss ◽  
Pearson Correlation ◽  
Video Quality ◽  
Ip Networks ◽  
High Variability ◽  
Digital Television ◽  
Packet Losses ◽  
Quality Estimation ◽  
Transport Stream ◽  
Proposed Model

This paper presents a model to predict video quality perceived by the broadcast digital television (DTV) viewer. We present how noise on DTV can introduce individual transport stream (TS) packet losses at the receiver. The type of these errors is different than the produced on IP networks. Different scenarios of TS packet loss are analyzed, including uniform and burst distributions. The results show that there is a high variability on the perceived quality for a given percentage of packet loss and type of error. This implies that there is practically no correlation between the type of error or the percentage of packets loss and the perceived degradation. A new metric is introduced, theweighted percentageof slice loss, which takes into account the affected slice type in each lost TS packet. We show that this metric is correlated with the video quality degradation. A novel parametric model for video quality estimation is proposed, designed, and verified based on the results of subjective tests in SD and HD. The results were compared to a standard model used in IP transmission scenarios. The proposed model improves Pearson Correlation and root mean square error between the subjective and the predicted MOS.

scholarly journals MAC-aware Loss Discrimination for Real-time Streaming Services in Wireless Networks

2020 ◽  
Vol 8 (6) ◽  
pp. 5047-5052
Keyword(s):  
Wireless Networks ◽  
Real Time ◽  
Packet Loss ◽  
Rate Control ◽  
Wireless Channel ◽  
Packet Losses ◽  
Streaming Applications ◽  
Wired Networks ◽  
Control Scheme ◽  
Channel Errors

This paper addresses the rate control problem for real-time applications streamed over wireless networks. In wired networks, an equation-based rate control such as TCP-friendly rate control (TFRC) can be used to control the rates of a source under the assumption that the loss is primarily due to congestion. But in wireless networks, packet loss may be due either to congestion or to channel errors. Thus, it is necessary to differentiate between packet loss due to wireless channel errors and that due to congestion. The MAC-aware rate control scheme for real-time streaming applications discriminates packet losses due to channel errors using the event generation in the MAC layer. The simulation results show that the MAC-aware rate control scheme has higher throughput than the rate control scheme without loss classification.

scholarly journals Influence of extracorporeal membrane oxygenation on serum microRNA expression

2019 ◽  
Vol 47 (12) ◽  
pp. 6109-6119
Author(s):  
M. Scettri ◽  
H. Seeba ◽  
D. L. Staudacher ◽  
S. Robinson ◽  
D. Stallmann ◽  
...  
Keyword(s):  
Extracorporeal Membrane Oxygenation ◽  
Real Time ◽  
Underlying Disease ◽  
Real Time Quantitative Pcr ◽  
Membrane Oxygenation ◽  
Serum Microrna ◽  
Clinical Biomarkers ◽  
Differentially Expressed Mirnas ◽  
Before And After ◽  
Medical Intensive Care

Objective To date, no biomarkers have been established to predict haematological complications and outcomes of extracorporeal membrane oxygenation (ECMO). The aim of this study was to investigate the expression of a panel of microRNAs (miRNAs), which are promising biomarkers in many clinical fields, in patients before and after initiating ECMO. Methods Serum miRNA levels from 14 patients hospitalized for acute respiratory failure and supported with ECMO in our medical intensive care unit were analysed before and 24 hours after ECMO. In total, 179 serum-enriched miRNAs were profiled by using a real-time PCR panel. For validation, differentially expressed miRNAs were individually quantified with conventional real-time quantitative PCR at 0, 24, and 72 hours. Results Under ECMO support, platelet count significantly decreased by 65 × 103/µL (25th percentile = 154.3 × 103/µL; 75th percentile = 33 × 103/µL). Expression of the 179 miRNAs investigated in this study did not change significantly throughout the observational period. Conclusions According to our data, the expression of serum miRNAs was not altered by ECMO therapy itself. We conclude that ECMO does not limit the application of miRNAs as specific clinical biomarkers for the patients’ underlying disease.

scholarly journals Adaptive Real-Time Routing Protocol for (m,k)-Firm in Industrial Wireless Multimedia Sensor Networks

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1633 ◽  
Author(s):  
Beom-Su Kim ◽  
Sangdae Kim ◽  
Kyong Hoon Kim ◽  
Tae-Eung Sung ◽  
Babar Shah ◽  
...  
Keyword(s):  
Real Time ◽  
Routing Protocol ◽  
Traffic Management ◽  
Research Area ◽  
Multimedia Data ◽  
Wireless Multimedia ◽  
Multimedia Sensor Networks ◽  
Proposed Model ◽  
Event Information ◽  
Firm Model

Many applications are able to obtain enriched information by employing a wireless multimedia sensor network (WMSN) in industrial environments, which consists of nodes that are capable of processing multimedia data. However, as many aspects of WMSNs still need to be refined, this remains a potential research area. An efficient application needs the ability to capture and store the latest information about an object or event, which requires real-time multimedia data to be delivered to the sink timely. Motivated to achieve this goal, we developed a new adaptive QoS routing protocol based on the (m,k)-firm model. The proposed model processes captured information by employing a multimedia stream in the (m,k)-firm format. In addition, the model includes a new adaptive real-time protocol and traffic handling scheme to transmit event information by selecting the next hop according to the flow status as well as the requirement of the (m,k)-firm model. Different from the previous approach, two level adjustment in routing protocol and traffic management are able to increase the number of successful packets within the deadline as well as path setup schemes along the previous route is able to reduce the packet loss until a new path is established. Our simulation results demonstrate that the proposed schemes are able to improve the stream dynamic success ratio and network lifetime compared to previous work by meeting the requirement of the (m,k)-firm model regardless of the amount of traffic.

scholarly journals Real-Time High-Level Acute Pain Detection Using a Smartphone and a Wrist-Worn Electrodermal Activity Sensor

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 3956
Author(s):  
Youngsun Kong ◽  
Hugo F. Posada-Quintero ◽  
Ki H. Chon
Keyword(s):  
Real Time ◽  
Electrodermal Activity ◽  
Smartphone Application ◽  
Real Time Processing ◽  
Pain Stimulation ◽  
Significant Difference ◽  
Before And After ◽  
Electrical Pulses ◽  
Pain Detection ◽  
High Level

The subjectiveness of pain can lead to inaccurate prescribing of pain medication, which can exacerbate drug addiction and overdose. Given that pain is often experienced in patients’ homes, there is an urgent need for ambulatory devices that can quantify pain in real-time. We implemented three time- and frequency-domain electrodermal activity (EDA) indices in our smartphone application that collects EDA signals using a wrist-worn device. We then evaluated our computational algorithms using thermal grill data from ten subjects. The thermal grill delivered a level of pain that was calibrated for each subject to be 8 out of 10 on a visual analog scale (VAS). Furthermore, we simulated the real-time processing of the smartphone application using a dataset pre-collected from another group of fifteen subjects who underwent pain stimulation using electrical pulses, which elicited a VAS pain score level 7 out of 10. All EDA features showed significant difference between painless and pain segments, termed for the 5-s segments before and after each pain stimulus. Random forest showed the highest accuracy in detecting pain, 81.5%, with 78.9% sensitivity and 84.2% specificity with leave-one-subject-out cross-validation approach. Our results show the potential of a smartphone application to provide near real-time objective pain detection.

scholarly journals SURG-03. IMMERSIVE VIRTUAL REALITY APPLICATIONS IN NEUROSURGICAL ONCOLOGY

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii461-iii461
Author(s):  
Andrea Carai ◽  
Angela Mastronuzzi ◽  
Giovanna Stefania Colafati ◽  
Paul Voicu ◽  
Nicola Onorini ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Real Time ◽  
New Technologies ◽  
Young Patients ◽  
Spatial Relationship ◽  
3D Models ◽  
Immersive Virtual Reality ◽  
Global Improvement ◽  
3D Rendering ◽  
Before And After

Abstract Tridimensional (3D) rendering of volumetric neuroimaging is increasingly been used to assist surgical management of brain tumors. New technologies allowing immersive virtual reality (VR) visualization of obtained models offer the opportunity to appreciate neuroanatomical details and spatial relationship between the tumor and normal neuroanatomical structures to a level never seen before. We present our preliminary experience with the Surgical Theatre, a commercially available 3D VR system, in 60 consecutive neurosurgical oncology cases. 3D models were developed from volumetric CT scans and MR standard and advanced sequences. The system allows the loading of 6 different layers at the same time, with the possibility to modulate opacity and threshold in real time. Use of the 3D VR was used during preoperative planning allowing a better definition of surgical strategy. A tailored craniotomy and brain dissection can be simulated in advanced and precisely performed in the OR, connecting the system to intraoperative neuronavigation. Smaller blood vessels are generally not included in the 3D rendering, however, real-time intraoperative threshold modulation of the 3D model assisted in their identification improving surgical confidence and safety during the procedure. VR was also used offline, both before and after surgery, in the setting of case discussion within the neurosurgical team and during MDT discussion. Finally, 3D VR was used during informed consent, improving communication with families and young patients. 3D VR allows to tailor surgical strategies to the single patient, contributing to procedural safety and efficacy and to the global improvement of neurosurgical oncology care.

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