41 research outputs found
Improving latency for interactive, thin-stream applications over reliable transport
A large number of network services use IP and reliable transport protocols. For applications with constant pressure of data, loss is handled satisfactorily, even if the application is latencysensitive. For applications with data streams consisting of intermittently sent small packets, users experience extreme latencies more frequently. Due to the fact that such thin-stream applications are commonly interactive and time-dependent, increased delay may severely reduce the experienced quality of the application. When TCP is used for thin-stream applications, events of highly increased latency are common, caused by the way retransmissions are handled. Other transport protocols that are deployed in the Internet, like SCTP, model their congestion control and reliability on TCP, as do many frameworks that provide reliability on top of unreliable transport. We have tested several application- and transport layer solutions, and based on our findings, we propose sender-side enhancements that reduce the application-layer latency in a manner that is compatible with unmodified receivers. We have implemented the mechanisms as modifications to the Linux kernel, both for TCP and SCTP. The mechanisms are dynamically triggered so that they are only active when the kernel identifies the stream as thin. To evaluate the performance of our modifications, we have conducted a wide range of experiments using replayed thin-stream traces captured from real applications as well as artificially generated thin-stream data patterns. From the experiments, effects on latency, redundancy and fairness were evaluated. The analysis of the performed experiments shows great improvements in latency for thin streams when applying the modifications. Surveys where users evaluate their experience of several applicationsâ quality using the modified transport mechanisms confirmed the improvements seen in the statistical analysis. The positive effects of our modifications were shown to be possible without notable effects on fairness for competing streams. We therefore conclude that it is advisable to handle thin streams separately, using our modifications, when transmitting over reliable protocols to reduce retransmission latency
Reducing Internet Latency : A Survey of Techniques and their Merit
Bob Briscoe, Anna Brunstrom, Andreas Petlund, David Hayes, David Ros, Ing-Jyh Tsang, Stein Gjessing, Gorry Fairhurst, Carsten Griwodz, Michael WelzlPeer reviewedPreprin
Kvasir-Capsule, a video capsule endoscopy dataset
Artificial intelligence (AI) is predicted to have profound effects on the future of video capsule endoscopy (VCE) technology. The potential lies in improving anomaly detection while reducing manual labour. Existing work demonstrates the promising benefits of AI-based computer-assisted diagnosis systems for VCE. They also show great potential for improvements to achieve even better results. Also, medical data is often sparse and unavailable to the research community, and qualified medical personnel rarely have time for the tedious labelling work. We present Kvasir-Capsule, a large VCE dataset collected from examinations at a Norwegian Hospital. Kvasir-Capsule consists of 117 videos which can be used to extract a total of 4,741,504 image frames. We have labelled and medically verified 47,238 frames with a bounding box around findings from 14 different classes. In addition to these labelled images, there are 4,694,266 unlabelled frames included in the dataset. The Kvasir-Capsule dataset can play a valuable role in developing better algorithms in order to reach true potential of VCE technology
Investigating the distribution of functionality for building a video server hypercube with IXP2400 cards
Streamed multimedia is becoming common on the Internet as the
bandwidths increase for end-users. To stream data with high
bitrates to many concurrent users, servers are needed that can handle
these extreme loads. Implementing servers in clusters to be able to meet
demands has proved to be a good strategy, providing scalability and performance. One commercial actor that has done this
successfully is nCube. Their n4x solution is a server
cluster based on a hypercube interconnection topology, and their
reported server performance is promising. However, the use of
special hardware for offloading routing increases the cost for
deploying this system. Network processing units have many similar
properties to the special hardware used by nCube. They are fully
programmable and optimized for networking tasks. In this thesis, we
start by charting the functionality and capabilities of the IXP2400 network
processor by implementing a series of test applications. Using
knowledge gained from this exploration, the design and implementation
of a video server hypercube prototype is done. We present an evaluation of the IXP2400 hardware
platform based on the test applications. Our video server cube
prototype is also presented and evaluated