We solve the problem of synchronizing a network of linear agents with unknown parameters and unknown network topology given that the Laplacian that defines it has no complex eigenvalues. To solve this problem, we use ...
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We solve the problem of synchronizing a network of linear agents with unknown parameters and unknown network topology given that the Laplacian that defines it has no complex eigenvalues. To solve this problem, we use a modified high order adaptation algorithm. We obtain conditions for reaching consensus with the proposed algorithm. We show modeling results that demonstrate the efficiency of the proposed approach.
The evolution of broadband connection technologies, along with the explosive growth of mobile handheld devices, has made video content one of the major Internet traffic types. HTTP adaptive streaming (HAS) is one fact...
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The evolution of broadband connection technologies, along with the explosive growth of mobile handheld devices, has made video content one of the major Internet traffic types. HTTP adaptive streaming (HAS) is one factor assisting the growing popularity of Internet video. One of its standards, the MPEG dynamic adaptive streaming over HTTP (DASH), allows users to access video streams of multiple resolutions available at a central repository. Various adaptation algorithms using the MPEG DASH protocol have been proposed, aiming to adapt the media bit rate delivered at the client to the current network conditions. In this paper, we present the FDASH rate adaptation scheme that employs fuzzy logic to control the buffering time and the video resolution delivered to the client in order to distribute video segments of the best quality, deliver undisrupted video playback, and avoid frequent changes of video resolution. The comparison of FDASH against other rate adaptation schemes shows that the former successfully provides the client with the optimal video rates, avoiding buffer underflows and unnecessary changes of video resolution in case of fluctuations of the available connection throughput.
In this paper, we propose a multi-band multi-channel adaptation algorithm to enhance the performance of single-hop mobile ad hoc networks (MANETs) running the IEEE802.11 standard. The algorithm takes into consideratio...
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ISBN:
(纸本)9781509055104
In this paper, we propose a multi-band multi-channel adaptation algorithm to enhance the performance of single-hop mobile ad hoc networks (MANETs) running the IEEE802.11 standard. The algorithm takes into consideration medium contention, coverage range and obstacle penetration in selecting both the operating band and the channel within the selected band. Applying the algorithm, a MANET with its usual highly-dynamic behavior, in terms of mobility and number of active stations, seeks a better operating environment according to its real-time practiced performance within the surrounding environment. The algorithm operates independently on each MANET without any type of coordination with other competing IEEE802.11 networks. Simulations are performed to demonstrate the performance of the proposed algorithm. The obtained results show its feasibility in enhancing the performance of a MANET over the fixed band and channel allocation strategies of the IEEE802.11 standard.
Adaptive video streaming using HTTP has become popular in recent years for commercial video delivery. The recent MPEG-DASH standard allows interoperability and adaptability between servers and clients from different v...
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ISBN:
(纸本)9781510601420
Adaptive video streaming using HTTP has become popular in recent years for commercial video delivery. The recent MPEG-DASH standard allows interoperability and adaptability between servers and clients from different vendors. The delivery of the MPD (Media Presentation Description) files in DASH and the DASH client behaviours are beyond the scope of the DASH standard. However, the different adaptation algorithms employed by the clients do affect the overall performance of the system and users' QoE (Quality of Experience), hence the need for research in this field. Moreover, standard DASH delivery is based on fixed segments of the video. However, there is no standard segment duration for DASH where various fixed segment durations have been employed by different commercial solutions and researchers with their own individual merits. Most recently, the use of variable segment duration in DASH has emerged but only a few preliminary studies without practical implementation exist. In addition, such a technique requires a DASH client to be aware of segment duration variations, and this requirement and the corresponding implications on the DASH system design have not been investigated. This paper proposes a segment-duration-aware bandwidth estimation and next-segment selection adaptation strategy for DASH. Firstly, an MPD file extension scheme to support variable segment duration is proposed and implemented in a realistic hardware testbed. The scheme is tested on a DASH client, and the tests and analysis have led to an insight on the time to download next segment and the buffer behaviour when fetching and switching between segments of different playback durations. Issues like sustained buffering when switching between segments of different durations and slow response to changing network conditions are highlighted and investigated. An enhanced adaptation algorithm is then proposed to accurately estimate the bandwidth and precisely determine the time to download the next optima
To realize the decoupling control of excitation and torque,Vector control of asynchronous motor requires accurate rotor flux position earring on rotor flux *** the indirect vector control scheme,the accuracy of the ro...
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ISBN:
(纸本)9781479919819
To realize the decoupling control of excitation and torque,Vector control of asynchronous motor requires accurate rotor flux position earring on rotor flux *** the indirect vector control scheme,the accuracy of the rotor flux orientation is influenced by the motor parameters,especially the rotor *** this paper,a new method for on-line correction of rotor resistance is *** this method,the rotor flux q axis component is obtained by the motor steady state model,we can design compensator based on the q axis component,which on-line adjust the rotor resistance to realize the rotor field *** method is simple and easy to be realized *** paper gives a detailed theoretical analysis and implementation *** validity of the algorithm is proved by the experimental results.
The treatment for motor disability's post-stroke involves repetitive training of affected limb to promote learning. Optimally designed sensor based solutions can complement the conventional approach of neuro-rehab...
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ISBN:
(纸本)9781538659250
The treatment for motor disability's post-stroke involves repetitive training of affected limb to promote learning. Optimally designed sensor based solutions can complement the conventional approach of neuro-rehabilitation with a therapist. In this paper, we present a novel algorithm based on patient's task performance. The proposed algorithm uses "enhanced Bi-directional adaptability," with slacking factor to ensure active participation of patients. This allows the system to adapt to the requirements of participants without pre-existing knowledge of patient's disability. This not only makes it compatible to a wider range of a patient but also reduces the time required for the adaptation. The simulated results for patients with various disability levels potentially demonstrate that the system can adapt to different levels of disability.
The density distribution and internal structure of bone relate to exterior loads on it. To study the remodeling process of trabecular bone, an adaptation algorithm with direction determination and stiffness modificati...
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ISBN:
(纸本)9783540368397
The density distribution and internal structure of bone relate to exterior loads on it. To study the remodeling process of trabecular bone, an adaptation algorithm with direction determination and stiffness modification was developed and applied to a 3D femoral finite element model. Material axes of every trabecular element were rotated to three principal stress directions determined from load cases in local coordinate system, then elastic and shear moduli were changed according to mechanical stimulus respectively. The calculation results have shown that the distribution of bone density and anisotropy degree corresponded well to the morphology of real femur, and trabeculae direction aligned with the known trabecular pattern. This orthotropic adaptation algorithm can simulate the remodeling process of femoral trabecular bone accurately.
A quality of experience (QoE) driven rate adaptation approach is proposed in this paper for adaptive HTTP streaming which jointly considers both bandwidth savings and video quality adaptation into account for the rate...
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A quality of experience (QoE) driven rate adaptation approach is proposed in this paper for adaptive HTTP streaming which jointly considers both bandwidth savings and video quality adaptation into account for the rate adjustment, beneficial to both service providers and subscribers. At each decision epoch, the adaptation algorithm accumulates for the time varying QoE of a viewer by accounting for all the impairments, namely, initial delay, quality transitions, and playback interruptions, which commonly occur during the playback of a video in adaptive streaming. Based on the possible bandwidth savings and resulting QoE variations, the algorithm decides on to adapt the bitrate dynamically and accordingly maximizes viewers' QoE. Since the proposed adaptation approach constructs an optimal path across the segments for adaptation, it also achieves QoE fairness among multiple clients in shared bandwidth environments. The experimental evaluation carried over real-world wireless network environments demonstrate that the proposed adaptation approach can maximize viewers' QoE in adaptive streaming, especially, under highly variable throughput conditions.
The requirements for video streaming have changed drastically during the past years. In today's Internet, high definition resolutions are considered default for videos, even in mobile settings, and with 4G penetra...
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ISBN:
(纸本)9781728105680
The requirements for video streaming have changed drastically during the past years. In today's Internet, high definition resolutions are considered default for videos, even in mobile settings, and with 4G penetration reaching 90 percent in the US, this no longer poses a big problem. However, while mobile bandwidth has increased, the battery life time of mobile devices has not increased significantly. Furthermore, current data plans are still not large enough to regularly stream movies during the commute. Users still resort to downloading media before travel. In this paper we propose a new HTTP adaptive streaming algorithm that delivers videos in high quality while avoiding stalling events, schedules the download of video segments so that a energy conserving idle state is often reached and keeps the buffer low at points in the video where many viewers abandon the video to save data. While most adaptive streaming algorithms optimize quality and stalling, this is the first attempt to use an adaptive streaming algorithm to reduce energy consumption. Since video streaming providers mostly care about the Quality of Experience when watching videos, energy efficiency is left to the device manufacturers. Therefore, both parties have little incentive to cooperate in this regard. But on the Internet of tomorrow, where most videos are watched on mobile devices, energy efficiency and the Quality of Experience must go hand in hand.
An adaptive inverse control algorithm is proposed for shock testing an arbitrary specimen using an electrodynamic actuator. The purpose is to ascertain whether the specimen can survive and continue to function under s...
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An adaptive inverse control algorithm is proposed for shock testing an arbitrary specimen using an electrodynamic actuator. The purpose is to ascertain whether the specimen can survive and continue to function under severe shock conditions. The main difficulty in shock control is that the specimen dynamics vary significantly and a control algorithm is required that adapts to the characteristics of a new specimen. The control algorithm used is the adaptive inverse control method, which approximates an inverse model of the loaded shaker with a finite impulse response adaptive filter, such that the reference input is reproduced at the shaker output. The standard filtered-x least mean square control structure used in the adaptive inverse control algorithm is modified to a block-processing structure, with the frequency-domain adaptive filter as the adaptation algorithm. Practical results show that the filtered-x frequency-domain adaptive filter control algorithm allows convergence of the shaker output to the assigned reference shock pulse.
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