2194314
Shared protection based on matrix decomposition in tropical semi-rings
It is observed that the singular value decomposition (SVD) transformation based on min-plus algebra (or called tropical semi-rings) leads to a very good characteristic in zero underestimating the reconstructed matrix. This paper introduces a novel distributed control framework for shared protection in optical networks with reduced routing information based on the tropical semi-rings technique, called sharing with reduced information with tropical semi-rings (SRI-TROP). The design of the proposed framework aims to initiate a compromise between the amount of link-state dissemination and the performance impairment due to the incompleteness of routing information, such that the precision in the link-state matrix reconstruction can efficiently map to the reduction in blocking probability. Based on the framework, a series of novel schemes are proposed, which are verified and compared with the reported counterparts in a simulation. The simulation results show that the performance in terms of the precision in the reconstructed link-state and the resultant blocking probability can be significantly improved.
61072281
A new scheme for lightpath restoration in wdm networks
All-optical networks with wavelength division multiplexing capability are the promising candidates for the next generation Internet. As these networks carry enormous bandwidth, it is not optional for them to be survivable. Although the available proactive restoration schemes provide 100% restoration guarantee, they require a huge extra capacity and usually result in an extremely high blocking probability. In this paper, we propose a novel active scheme that uses multiple predefined but not reserved backup paths along a working path to restore the lightpath in the event of link-failure. Simulation results based on two typical networks indicate that our new restoration method can reduce blocking probability and capacity requirement significantly while guaranteeing a very high restoration probability.
30106346
A Genetic Algorithm for Dynamic Routing and Wavelength Assignment in WDM Networks
In this paper, we study the challenging problem of Dynamic Routing and Wavelength Assignment (DRWA) in WDM (Wavelength-Division-Multiplexing) networks with wavelength continuity constraint, and propose an improved genetic algorithm (GA) for it. By adopting a new fitness function to consider simultaneously the path length and number of free wavelengths in cost estimation of a route, the new genetic RWA algorithm can achieve a good load balance among route candidates and result in a lower blocking probability than both the fixed alternative routing algorithm and the previous GA-based algorithm for DRWA, as verified by an extensive simulation study upon the ns-2 network simulator and some typical network topologies.
42869695
Dynamic RWA Based on the Combination of Mobile Agents Technique and Genetic Algorithm in WDM Networks with Sparse Wavelength Conversion
In this paper, we study the dynamic RWA problem in WDM networks with sparse wavelength conversion and propose a novel hybrid algorithm for it based on the combination of mobile agents technique and genetic algorithm. By keeping a suitable number of mobile agents in the network to cooperatively explore the network states and continuously update the routing tables, the new hybrid algorithm has the ability to promptly determine the first population of routes for a new request based on the routing table of its source node without requiring the time consuming process associated with the available GA-based dynamic RWA algorithms. To achieve a good load balance in WDM networks with sparse wavelength conversion, we adopt in our hybrid algorithm a new reproduction scheme and a new fitness function that simultaneously takes into account the path length, number of free wavelengths and wavelength conversion capability in route selection. Our new algorithm has the capabilities of achieving a better load balance and resulting a significantly lower blocking probability than that of the promising fixed-alternate routing algorithm for both the optical networks with sparse and full-range wavelength converters and the optical networks with sparse and limited-range wavelength converters, as verified by an extensive simulation study upon the ns-2 network simulator. The ability to guarantee both a low blocking probability and a small setup delay makes the new hybrid dynamic RWA algorithm very attractive for both the optical circuit switching networks and future optical burst switching networks.
5799803
Protection mechanisms for application service hosting platforms
The application service hosting platform (ASHP) has recently received tremendous attention from both industry and academia. An ASHP provides a shared high-performance infrastructure to host different application services (AS), outsourced by application service providers (ASP). In this paper, we focus on the protection of ASHP which has inherent requirement of sharing, openness, and mutual isolation. In contrast to a dedicated server platform, which is analogous with a private house, an ASHP is like an apartment building, involving the 'host' - the ASHP infrastructure, and the 'tenants' - the AS. Strong protection and isolation must be provided between the host and the tenants, as well as between different tenants. Unfortunately, traditional OS architecture and mechanisms are not adequate to provide strong ASHP protection. In this paper we first make the case for a new OS architecture based on the virtual OS technology. We then present three protection mechanisms we have developed in SODA, our ASHP architecture. The mechanisms include: (1) resource isolation between AS; (2) virtual switching and firewalling between AS; and (3) kernelized intrusion detection and logging for each AS. For (3), we have developed a system called Kernort inside the virtual OS kernel. Kernort detects network intrusions in real-time and logs AS activities even when the AS has been compromised. Moreover for the privacy of AS, logs are encrypted by Kernort so that the 'landlord' (namely ASHP owner) cannot view them without authorization. We are applying SODA to iShare, an Internet-based distributed resource sharing platform.
45958635
Micro power meter for energy monitoring of wireless sensor networks at scale
18153606
Virtual distributed environments in a shared infrastructure
We have developed a middleware system that integrates and extends virtual machine and virtual network technologies to support mutually isolated virtual distributed environments in shared infrastructures like the grid and the PlanetLab overlay infrastructure. Integrating virtual network and on-demand virtual machine creation and customization technologies makes virtual distributed environments a reality. The Violin-based middleware system integrates and enhances such technologies to create virtual distributed environments.
12509330
Approximate Information Flows: Socially-Based Modeling of Privacy in Ubiquitous Computing
In this paper, we propose a framework for supporting sociallycompatible privacy objectives in ubiquitous computing settings. Drawing on social science research, we have developed a key objective called the Principle of Minimum Asymmetry, which seeks to minimize the imbalance between the people about whom data is being collected, and the systems and people that collect and use that data. We have also developed Approximate Information Flow (AIF), a model describing the interaction between the various actors and personal data. AIF effectively supports varying degrees of asymmetry for ubicomp systems, suggests new privacy protection mechanisms, and provides a foundation for inspecting privacy-friendliness of ubicomp systems.
14786472
CoarseZ Buffer Bandwidth Model in 3D Rendering Pipeline
Depth traffic occupies a major portion of 3D graphics memory bandwidth. In order to reduce depth reading, we propose employing a low-resolution depth buffer, namely CoarseZ buffer, for tile-level depth culling before per-pixel test. The maximum depth of a tile is stored in the corresponding entry of CoarseZ buffer. Simulation results show that a small CoarseZ buffer can achieve remarkably high culling rate and significantly reduce z-reading bandwidth. We build a model that quantifies the influence of the CoarseZ design parameters on its efficiency and bandwidth. Test results of industrial benchmarks show that CoarseZ with tile size of 4 and bit depth of 16 can be a best selection to reduce memory bandwidth