Many practical systems are often involved in sequence-dependent failure behaviors. The efficiency of analyzing these dynamic systems is limited by addressing sequential failure events (SFEs). The survival signature method has the potential to address this issue. However, the survival signature cannot be applied directly due to the existence of SFEs. In this article, the adapted survival signature-based methods are developed for the rapid analysis of dynamic systems modeled by dynamic fault trees with priority-andgates. First, we deduce the probabilistic expressions of SFEs under the survival signature paradigm using conditional probability. Second, an analytical method for accurately computing the survival signatures of dynamic systems is proposed. Third, for large-scale and highly coupled dynamic systems, a semianalytical method is proposed to obtain the survival signature through simulating the Boolean states of SFEs under given components’ state. Several numerical and practical engineering cases are examined to highlight the superiority of the proposed methods compared with the sequential binary decision diagram method and coarse Monte Carlo simulation.

The Public Protection and Disaster Relief (PPDR) sector is undergoing an important transition with the deployment of Mission Critical (MC) mobile broadband technology based on 3GPP standards, with multiple initiatives on-going worldwide for providing PPDR agencies with broadband communications capabilities. One common approach being adopted is the delivery of MC services together with commercial traffic over public mobile networks and the use of prioritization mechanisms to protect the MC connections in congestion situations. However, this approach leaves commercial traffic unprotected in front of a non-controlled surge of MC traffic in specific cells since all resources would be allocated to serve this traffic. In this context, this paper proposes a solution to properly multiplex MC and commercial services with congestion protection for both types of services. The solution is based on the exploitation of the network slicing features brought into the new 5G standards. In particular, the paper describes how different slices can be parameterized in a 5G Radio Access Network (RAN) so that radio load guarantees can be established for each type of service. The proposed solution is evaluated in an illustrative scenario by means of simulations. Obtained results show the improvements in traffic isolation achievable by the slicing configuration when compared to the solution that only relies on prioritization mechanisms.

With worldwide shipments of smartphones (487.7 million) exceeding PCs (414.6 million including tablets) in 2011, and in the US alone, more users predicted to access the Internet from mobile devices than from PCs by 2015, clearly there is a desire to be able to use mobile devices and networks like we use PCs and wireline networks today. However, in spite of advances in the capabilities of mobile devices, a gap will continue to exist, and may even widen, with the requirements of rich multimedia applications. Mobile cloud computing can help bridge this gap, providing mobile applications the capabilities of cloud servers and storage together with the benefits of mobile devices and mobile connectivity, possibly enabling a new generation of truly ubiquitous multimedia applications on mobile devices: Cloud Mobile Media (CMM) applications.

Cloud Mobile Gaming (CMG) [1][10][11] has been proposed as an approach to enable rich Internet games on mobile devices, where the rendering of the games is performed on cloud servers, as opposed to on mobile devices. Though promising, the CMG approach may require significant cloud computing resources for the concurrent gaming sessions, and even more critically, significant bandwidth for delivering the rendered videos back to mobile devices, leading to high cloud costs, and questions regarding resource constrained wireless networks. This paper addresses the problem of making the CMG approach scalable and economically feasible by proposing a novel Wireless Cloud Scheduler (WCS), which can increase the number of simultaneous CMG sessions that can be supported while ensuring Mobile Gaming User Experience (MGUE)[1] with the available wireless network resources, while minimizing the cloud service cost incurred by the CMG provider. Unlike conventional network schedulers, WCS considers simultaneously the constraints of the wireless networks that may be available to each CMG user, including cellular and WiFi, as well as the cost of available cloud resources, while scheduling the most optimal wireless link and cloud server for each CMG session. To further enhance the performance of WCS, we also propose a joint scheduling-adaptation algorithm, that can systematically leverage adaptation techniques introduced in [10][11] to adapt the communication needs of in-service users if the available wireless network bandwidth is not sufficient for a new CMG user. Our simulation results demonstrate that the use of WCS, and the joint scheduling-adaptation algorithm, can significantly improve the performance of the CMG approach, increasing the number of simultaneous CMG sessions that can be supported, while maximizing aggregate MGUE and minimizing the average cloud service cost.

A new Cloud Mobile Gaming (CMG) approach, where the responsibility of executing the gaming engines, including the most compute intensive tasks of graphic rendering, is put on cloud servers instead of the mobile devices, has the potential for enabling mobile users to play the same rich Internet games available to PC users. However, the mobile gaming user experience may be limited by the communication constraint imposed by available wireless networks and computation constraint imposed by the cost and availability of cloud servers. In this paper, we propose a rendering adaptation technique which can adapt the game rendering parameters to satisfy CMG communication and computation constraints, such that the overall mobile gaming user experience is maximized. Experiments conducted on a commercial UMTS network demonstrate that the proposed rendering adaptation techniques can make the CMG approach feasible: ensuring protection against wireless network conditions, and ensuring server computation scalability, thereby ensuring acceptable mobile gaming user experience.

A new remote server based gaming approach, where the responsibility of executing the gaming engines is put on remote servers instead of the mobile devices, has the potential for enabling mobile users to play the same rich Internet games available to PC users. However, the mobile gaming user experience may be limited by risks of unacceptably high response time, and low gaming video quality, as gaming control commands, and the resulting gaming video, have to travel through wireless networks characterized by high bandwidth fluctuations, latency and packet loss. In this paper, we propose a set of application layer optimization techniques to ensure acceptable gaming response time and video quality in the remote server based approach. The techniques include downlink gaming video rate adaptation, uplink delay optimization, and client play-out delay adaptation. Experiments conducted on a commercial HSDPA network demonstrate that the proposed optimization techniques can make the remote server based approach feasible, allowing rich Internet games to be played on mobile devices, while ensuring acceptable user experience.

With the evolution of mobile devices and networks, and the growing trend of mobile Internet access, rich, multi-player gaming using mobile devices, similar to PC-based Internet games, has tremendous potential and interest. However, the current client-server architecture for PC-based Internet games, where most of the storage and computational burden of the game lies with the client device, does not work with mobile devices, constraining mobile gaming to either downloadable, single player games, or very light non-interactive versions of the rich multi-player Internet games. In this paper, we study a cloud server based approach, termed Cloud Mobile Gaming (CMG), where the burden of executing the gaming engines is put on cloud servers, and the mobile devices just communicate the users' gaming commands to the servers. We analyze the factors affecting the quality of user experience using the CMG approach, including the game genres, video encoding factors, and the conditions of the wireless network. Based on the above analysis, we develop a model for Mobile Gaming User Experience (MGUE), and develop a prototype for real-time measurement of MGUE that can be used in real networks. We validate MGUE model using controlled subjective testing, and then use it to characterize user experience achievable using the CMG approach in wireless networks.