Impact Of Transmission Delay Research Articles

Experimental network performance evaluation for human-robot interaction collision detection using cameras

A practical solution to human-robot collision detection using devices commonly found in workplaces, such as 2D cameras, requires thorough planning and evaluation of network restrictions that may deny timely access to and process important context data collected by IoT devices. In this study, we evaluate the behavior of the AMQP and MQTT application protocols for camera image transmission. We examine the packet overhead for each protocol when streaming video signals. Also, we evaluate the impact of transmission delay on the total decision time starting from the moment the camera captures an image to the moment it is decided if there is a robot-human collision or not. Finally, we also evaluated an open-source platform to emulate wireless Mininet-wifi, seeking to understand the level of influence it would have on the results. The results show that transmission overhead represents as much as 80% of the total decision time and that the AMQP protocol takes around 5% less transmission time than MQTT. The results also show that the use of hardware accelerators such as a GPU increases by 37 times the number of detections. We found that the size of the image to be transmitted and wireless communications did not influence the results for our scenario. In addition, we also noticed that the use of emulation through Mininet-wifi does not negatively influence the behavior of the experiments.

ALBLP: Adaptive Load-Balancing Architecture Based on Link-State Prediction in Software-Defined Networking

Load-balancing optimization in software-defined networking (SDN) has been researched for a long time. Researchers have proposed many solutions to the load-balancing problem but have rarely considered the impact of transmission delay between controllers and switches under high-load network conditions. In this paper, we propose an adaptive load-balancing architecture based on link-state prediction (ALBLP) in SDN that can solve the influence of transmission delay between controllers and switches on network load balancing. ALBLP constructs the prediction model of the network link status, adopts the long-term and short-term memory neural network (LSTM) algorithm to predict the network link-state value, and then uses the predicted value as the Dijkstra weight to calculate the optimal path between network hosts. The proposed architecture can adaptively optimize network load balancing and avoid the empty window period, in which the switch flow table does not exist by actively issuing the flow table. Under the network architecture, we collect the data set of the network link-state by simulating the GÉANT network, and we verify the effectiveness of the proposed algorithm. The experiment results show that the ALBLP proposed in this paper can optimize load balancing in SDN and solve the problem of transmission delay between controllers and switches. It has a maximum load-balancing improvement of 23.7% and 11.7% in comparison with the traditional Open Shortest Path First (OSPF) algorithm and the reinforcement learning method based on Q-Learning.

Distributed Data Traffic Scheduling With Awareness of Dynamics State in Cyber Physical Systems With Application in Smart Grid

The design of communication infrastructure in cyber physical system (CPS) is of vital importance for proper operations of physical dynamics. In this paper, the scheduling of packet transmission over wireless communication networks in CPS is studied for the purpose of system state stabilization. To measure the effective information amount of different packets, the concept of virtual queue (VQ) is defined based on the delay-tolerant Kalman filtering. VQ-based back pressure algorithm is proposed for the distributed data traffic scheduling. The impact of transmission delays on VQ lengths is also studied for the formulation of distributed scheduling strategy. The scheduling method is then applied in the context of voltage control in microgrid and is demonstrated to achieve better performance than general scheduling algorithm without the awareness of dynamics state. Further numerical simulations of data traffic scheduling considering transmission delay are carried out to demonstrate the validity of the scheduling algorithm, which is established according to VQ lengths affected by transmission time delays.

The Impact of Transmission Delays on Mission Control-Space Crew Communication

During long duration missions space-ground communications will involve delays up to 20 minutes one way, a reality that poses a formidable challenge to team communication and task performance. In the present research we examined how transmission delays impacted the interactions between mission controllers and space crews during routine and off-nominal tasks. Method: Four teams of NASA flight controllers and astronauts participated in a space simulation study involving two 2-hour scenarios with transmission delays of 50 sec and 300 sec. Audio-recordings of space - ground communications were transcribed and their structure (turn taking and sequence) and content examined; specifically, whether speakers identified addressees or themselves, and whether listeners confirmed their understanding. Results and Discussion: Transmission delays disrupted the structure of space-ground communications as contributions by flight controllers and astronauts overlapped or were out of sequence. Space crewmembers and flight controllers did not consistently mark the end of their turn; however, our findings suggest that they were more likely to do so under the longer transmission delay. Omissions of identifiers and inadequate listener feedback were observed under both delay conditions. Strategies supportive of grounding processes were also identified.

Impact of transmission delay in audiovisual communications

AbstractIn this paper, the design and results are presented of an experimental study which was conducted in order to assess subjectively the impact of transmission delay in audiovisual communications. This study was undertaken using two 64 kb/s videotelephones which were connected over links incorporating simulated one‐way circuit propagation delays of 0 ms, 250 ms and 500 ms. From the results obtained it was concluded that audiovisual communication is weakly affected by propagation delay. In general, performance degradation between terrestrial and single‐hop satellite connections was minimal and in most cases statistically insignificant. A subsidiary conclusion is that the presence of the visual cues appears to mitigate the impact of transmission delay in audiovisual communication.