Danyu Zhu

QoS aware wireless bandwidth aggregation (QAWBA) by integrating cellular and ad-hoc networks

Some mobile devices are beginning to support both cellular and IEEE 802.11 based network interfaces. Although rates are increasing, current cellular networks provide relatively low bandwidth that do not meet the QoS requirements of many high-demanding multimedia applications. In this paper, we propose an integrated network architecture that utilizes both wireless interfaces to provide better QoS support by QoS aware wireless bandwidth aggregation (QAWBA). Via QAWBA, mobile nodes form a mobile ad hoc network (MANET) using their IEEE 802.11 interfaces to share their cellular link capacity. Some mobile nodes act as proxies to contribute their idle cellular links to support a QoS request that may exceed the available bandwidth of any individual mobile node. A K-path proxy discovery algorithm is proposed for fast and efficient proxy discovery. Simulation results show that QAWBA can significantly improve network utilization and the admission rate of QoS requests.

Development of supermedia interface for telediagnostics of breast pathology

A robotic device with haptic, tactile, and ultrasound capabilities, which can acquire and render information of breast pathology was developed. A physician interface that can examine the human breast remotely and accurately, using such a robotic device was also developed. Such a robotic device can be used to do screening or focused breast exams for patients in remote areas without convenient access to physicians. Because of in-situ ultrasound imaging, examination by the robotic device may prove to be more accurate than examination by the physicians own hand. In addition, the robotic device can also be used to train healthcare professionals in breast pathology

Supermedia transport for teleoperations over overlay networks

In real-time Internet based teleoperation systems, the operator controls the robot and receives feedback through the Internet. Supermedia refers to robotic control commands, video, audio, haptic feedback, and other sensory information in the control system. Traditional transport services may not be able to meet the timely transmission requirements and dynamic priority changes of supermedia streams. Supermedia TRansport for teleoperations over Overlay Networks (STRON) uses multiple disjoint paths and forward error correction encodings to reduce end-to-end latency for supermedia streams. Network routes and encoding redundancy may be adjusted dynamically to meet the supermedia QoS requirements. NS2 simulations and evaluations using available bandwidth traces from globally distributed computing nodes show that STRON can significantly reduce latency compared with available transport services.

Supermedia Interface for Internet-based Telediagnostics of Breast Pathology

We present our development of a supermedia interface for telediagnostics of breast pathology via the Internet. Supermedia is the incorporation of multiple media and data streams, such as audio, video, ultrasound images, and tactile and haptic sensor data for enhanced telepresence capabilities. Our supermedia interface comprises an anthropomorphic arm/hand equipped with haptic and tactile sensing, ultrasound imaging capabilities, a physician interface capable of rendering both haptic and tactile information, and two-way audio and video. The supermedia interface was tested via the Internet and enables telediagnostics. Preliminary experiments with silicone breast models have demonstrated the e fectiveness of the supermedia interface for telediagnostics. The interface is expected to enhance and improve the diagnostic performance of breast pathology as well as promote telediagnostics in remote areas and for patients with cultural barriers.

Improved transport service for remote sensing and control over wireless networks

In a bilateral teleoperated system, the signal transmissions between the operator and the slave manipulators have different QoS requirements in comparison to traditional network traffic. Running teleoperated systems over wireless networks poses more challenges in comparison to wired networks. The media streams involved differentiate themselves from other media types in that they require both reliable and smooth delivery. Reliable delivery requires the transport service to have TCP style semantics. By being smooth, the transport service should be able to deliver the control and sensing data with bounded and reduced latency and its variation. For example, we have conducted numerous teleoperated experiments using our system. We have found in some of our applications that if the end-to-end latency variance becomes larger than 0.3 second, the operator has difficulty maintaining smooth control of the slave manipulator. However, our simulations show that using TCP, the end-to-end latency variance can be as much as 2.5 seconds in an ad hoc wireless network. This paper proposes an improved transport service for remote sensing and control (TRSC). The service reduces the end-to-end latency and latency variance (jitter) for real-time reliable media in mobile ad hoc networks by using forward error correction encoding and multiple network paths. Simulation using NS2 shows the approach performs well under different wireless scenarios

Supermedia Interface for Internet Based Tele-diagnostics of Breast Pathology

This paper presents our development of a supermedia interface for tele-diagnostics of breast pathology via Internet. Supermedia is the incorporation of multiple media and data streams, such as audio, video, ultrasound images, and tactile and haptic sensor data for enhanced telepresence capabilities. Our supermedia interface is comprised of an anthropomorphic arm/hand equipped with haptic and tactile sensing, ultrasound imaging capabilities, a physician interface capable of rendering both haptic and tactile information, and two-way audio and video. The supermedia interface was tested via the Internet and enables tele-diagnostics. Preliminary experiments had demonstrated the effectiveness of the developed supermedia tele-diagnostic interface. That is, it will greatly enhance and improve the diagnostic performance as well as promote the tele-diagnostics of breast pathology in remote areas a reality

Networked Human/Robot Cooperative Interface for Tele-diagnostics of Breast Pathology

This paper presents our development of a network-enabled human/robot cooperative interface for tele- diagnostics of breast pathology. To enhance telepresence capabilities, our human/robot interface is comprised of an anthropomorphic arm/hand equipped with haptic and tactile sensing, ultrasound imaging capabilities, a physician interface capable of rendering both haptic and tactile information, and two-way audio and video. This cooperative and multimedia interface was tested via the Internet and enables tele-diagnostics. Preliminary experiments had demonstrated the effectiveness of the developed human/robot tele-diagnostic interface. That is, it will greatly enhance and improve the diagnostic performance as well as promote the tele-diagnostics of breast pathology in remote areas a reality.