Recently, some researchers have performed extensive experiments to study the feasibility and performance of vehicle drive-thru access to roadside access points (APs). The experiments demonstrate that the duration of connectivity to the AP is limited. A drive-thru vehicle has an area of high signal strength near the AP, but experiences poor link quality when entering or exiting the AP coverage area. Since a vehicle spends a large portion of the connection time in this poor link quality area, the data throughput can be significantly reduced. This problem has been identified in several works, but a viable solution has yet to be identified. In this paper, we propose a vehicle-to-vehicle relay (V2VR) scheme which extends the service range of roadside APs and allows drive-thru vehicles to maintain high throughput within an extended range. Our solution is distributed and purely client-based, without any modification to the existing 802.11 APs. Through implementation and simulation, we demonstrate that the V2VR scheme can effectively extend the drive-thru access range and improve the network utilization for drive-thru vehicles.
IBM has designed special cryptographic processors for its servers for more than 25 years. These began as very simple devices, but over time the requirements have become increasingly complex, and there has been a never-ending demand for increased speed. This paper describes the PCIXCC, the new coprocessor introduced in the IBM z990 server. In many ways, PCIXCC is a watershed design. For the first time, a single product satisfies all requirements across all IBM server platforms. It offers the performance demanded by today s Web servers, it supports the complex and specialized cryptographic functions needed in the banking and finance industry, and it uses packaging technology that leads the world in resistance to physical or electrical attacks against its secure processes and the secret data it holds. Furthermore, it is programmable and highly flexible, so that its function can be easily modified to meet new requirements as they appear. These features are possible because of innovative design in both the hardware and embedded software for the card. This paper provides an overview of that design.
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