Jui-Hao Chiang

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Memory virtualization abstracts a physical machine's memory resource and presents to the virtual machines running on it a piece of physical memory that could be shared, compressed and moved. To optimize the memory resource utilization by fully leveraging the flexibility afforded by memory virtualization, it is essential that the hypervisor have some sense(More)
Clock synchronization is an essential building block for many control mechanisms used in wireless networks, including frequency hopping, power management, and packet scheduling. Although the IEEE 802.11 standard [1] provides a clock synchronization mechanism for multi-hop wireless networks, it has well-documented accuracy problems [2], [3] because the(More)
A major barrier to advancing modern wireless networking research is the lack of an effective wireless network simulation platform that simultaneously offers high fidelity, scalability, reproducibility and ease of use. MiNT [8], [7] is an innovative wireless network emulation platform that is specifically designed to satisfy all these desirable properties.(More)
Modern virtualization technologies have a powerful ability to move a virtual machine (VM) from one physical machine to another, which enables unprecedented flexibility for system fault tolerance and load balancing. However, for physical machines there is no similar capability. This paper describes the detailed design of migrating a physical machine's state(More)
Memory de-duplication removes the memory state redundancy among virtual machines that run on the same physical machine by identifying common memory pages shared by these virtual machines and storing only one copy for each of common memory pages. A standard approach to identifying common memory pages is to hash the content of each memory page, and compare(More)
The effectiveness of a modern hyper visor on a virtualized server is measured by its consolidation ratio, which is defined as the maximum number of virtual machines (VM) that can run on a physical server without performance degradation. A key factor in determining a hyper visor's consolidation ratio is its effectiveness in fairly distributing a virtualized(More)
Minimizing the total amount of physical memory consumption of the virtual machines (VM) concurrently running on a physical server is a key to improving a hyper visor's consolidation ratio, defined as the maximum number of VMs that can run on a physical server without performance degradation. This paper describes the design, implementation and evaluation of(More)
A powerful functionality enabled by modern virtualization technologies is the ability to move a virtual machine (VM) from one physical machine to another, which enables unprecedented flexibility for system fault tolerance and load balancing. However, no similar capability exists for physical machines. This paper describes the first known successful(More)
A voice-over-IP (VoIP) gateway bridges IP-based packet-switched networks (i.e. Internet) with public circuit-switched telephone networks (i.e. PSTN). The key building block of a VoIP gateway is a telephony card that interfaces with the PSTN and converts signals from the PSTN to bits that can be manipulated by a computer and vice versa. Because commercially(More)