In this paper, we describe the design of menus for multiuser digital tabletops. On direct input surfaces, occlusions created by the user's hand decrease interaction performance with menus. The key design criteria are to avoid these occlusions and to adapt the menu placement to the user's handedness and position on the tabletop. We present an adaptive menu placement method based on direct touch and pen tracking that allows correct menu placement around the table. As an extension, we propose adding a gesture input area for fast interaction which can be partly occluded by the user's hand.

This paper describes an overload control scheme for web servers which integrates admission control and load balancing. The admission control mechanism adaptively determines the client request acceptance rate to meet the web servers' performance requirements while the load balancing or client request distribution mechanism determines the fraction of requests to be assigned to each web server. The scheme requires no prior knowledge of the relative speeds of the web servers, nor the work required to process each incoming request.

No abstract

Abstract-In this paper we describe the process that we undertook to build a configurable wireless platform that can be used to implement cognitive radio network (CRN) architectures. Consisting of a commodity IEEE 802.11 a/b/g (WiFi) router at the physical (PHY) layer and RF signal processing and IP traffic shaping circuitry, the resultant hybrid terminal (called the WiFi CR) becomes a building block that can implement cognitive femtocells, point to multipoint, mesh, and relay wireless networks. The IP addressable WiFi CR terminals can sense their radio environment, schedule IEEE 802.11 packet transmissions in space and time, and select channel, modulation rates, and transmit power. Intelligent operation is undertaken by a cognitive network management system (CR NMS) which controls a number of WiFi CR terminals and solicits sensor information from them. The CR NMS gathers the spectrum and sensed interference information and builds a memory map with such knowledge, thereby creating radio environment awareness for the CRN. Cognitive engines (the intelligent control algorithms) within the CR NMS use radio environment knowledge and other information (such as spectrum policy) to give the system a capability to seek white space spectrum, avoid interference, identify primary users, and take on other tasks associated with cognitive radio (CR). Designed around ISM band operation, this generic terminal, with proper RF modifications, can work in the TV bands, 3.65-3.70 GHz, and up to 60 GHz.

No abstract