Integrating wireless EEGs into medical sensor networks

Wireless Electroencephalograms (EEG) are currently being used to wirelessly transmit the data from brain sensors to a computer and they carry huge potential for many future medical applications. This paper presents the design of a hy-brid medical sensor network with Tmote Sky motes as wire-less EEG sensor nodes at the lowest level collecting EEG signals and sending them to Stargate PDAs at the next level. Stargates perform artifact removal, Fourier transfor-mation and feature extraction and the final machine intelli-gence algorithms are run at a PC server. Several features of the CodeBlue medical sensor network like query processing, routing layer are used in our design. The advantages of the hybrid medical sensor network integrating wireless EEGs include the capability to have the brain monitoring func-tionality incorporated into the medical sensor networks. ACM Classificatio

Test design for computer network protocols

Communication protocol testing can be done with a test architecture consisting of remote Tester and local Responder processes. By ignoring interaction primitive parameters and additional state variables, it is possible to adapt test sequence generation techniques for finite state machines (FSM) to generate sequences for protocols specified as incomplete finite state machines.For real protocols, tests can be designed based on the formal specification of the protocol which uses an extended FSM model in specifying the transition types. The transition types are transformed into a simpler form called normal form transitions which can be modelled by a control and a data flow graph. Furthermore, the data flow graph is partitioned to obtain disjoint blocks representing the different functions of the protocol. Tests are designed by considering parameter variations of the input primitives of each data flow function and determining the expected outputs. This methodology gives complete test coverage of all data flow functions and tests for unspecified cases can be designed using the control and data flow graphs. The methodology is applied to two real protocols: Transport protocols Classes 0 and 2

Multimedia Communication in Wireless Networks with an Evaluation of Slot Aggregation in PACS

A novel application on the recently emerging Personal Communication Services (PCS) networks is the multimedia communication. We discuss the requirements for providing multimedia service over the PCS networks. Video coding, channel (slot) aggregation, bandwidth and quality of service aspects are identified to be of prime importance for multimedia communication. Next, slot aggregation and data-sense multiple access techniques of Bellcore's PACS standard are studied. Two channels of PACS are investigated using simulation. It is shown that the IMP channel can only provide very low speeds. The packet protocol channel (PPC) on the other hand offers much higher speeds both on the downlink and uplink and seems more suitable for multimedia communication at MPEG-4 speeds

Design of IP-based Routing in a LEO Satellite Network

This paper presents the architecture and operational principles of a mobile data network with a Teledesic-like low-earth orbit (LEO) satellite backbone. The mission of the network is to provide worldwide data communication compatible with the Internet. First, a precise de nition of the network architecture which consists of LEO's with intersatellite links, gateway stations, standard terminals and mobile terminals is given. The proposed model is a hybrid design in which the responsibilities for routing and user tracking are shared between the satellites and gateway stations. Based on the model, a unicast routing algorithm, compatible with the Internet Protocol (IP), is developed. Analytical modelling is developed establishing the delay properties of unicast datagrams. Finally video and audio transmission in the network are considered. It is shown by simulation that the network can provide low delay and high frame rate audio and video transmission to mobile users

Multimedia Communication in Cellular PACS Network

A novel application on the recently emerging Personal Communication Services (PCS) networks is the multimedia communication. In this paper, we evaluate multimedia communications capability of one of the PCS standards, Personal Access Communications System's (PACS) packet channel (PPC) using simulation modeling. The performance of PPC's slot aggregation and data-sense multiple access techniques are studied by considering the downlink and uplink in a single cell and combined uplink/downlink in two cells and changing various parameters such as the number of users and certain protocol parameters. Interconnection of PPC with the Internet is discussed next. Frame rates of MPEG-1 coded images transmitted in a PACS cell as IP datagrams are determined. Handover characteristics of PPC downlink are studied by changing different parameters such as the cell size, the speed of the mobile host and time between handovers. The results clearly establish that multimedia communication on PPC is only feas..

Architectural Support for Designing Fault-Tolerant Open Distributed Systems

A distributed system consists of autonomous computing modules that interact with each other using messages. Designing distributed systems is more difficult than designing centralized systems for several reasons. Physical separation and the use of heterogeneous computers complicate interprocessor communication, management of resources, synchronization of cooperating activities, and maintenance of consistency among multiple copies of information. The main advantages of distributed systems include increased fault-tolerance capabilities through the inherent redundancy of resources, improved performance by concurrently executing a single task on several computing modules, resource sharing, and the ability to adapt to a changing environment (extensibility). Distributed systems cover a wide range of applications, recent advances in VLSI devices and network will further increase the use of distributed systems. As the complexity of these systems increases, so does the probability of component failure, which can adversely affect the performance and usefulness of such systems. Thus, reliability, availability, and fault tolerance become important design issues in distributed systems. Fault tolerance is the system’s ability to continue executing despite the occurrence of failures. Increasing the reliability and fault tolerance of a system involves a trade-off between the cost of failure (for example, costs incurred by incomplete or incorrect computations) and the cost of incorporating the redundancy and recovery mechanisms. Because of their inherent redundancy, distributed systems provide a cost-effective way to apply fault-tolerance techniques. Open distributed systems provide universal connectivities among their components because their designs are based on the standard protocols adopted by the international standard organization (ISO). In this computing environment, interacting processes communicate through messages that traverse a stack of software layers. Consequently, applying fault-tolerance techniques to execute critical tasks can be costly in terms of execution time. In this article, we first provide an overview of the main techniques for designing fault-tolerant software and hardware systems. We identify the important features of the building blocks (computers, memories, buses, etc.) that can support an efficient implementation of fault-tolerant open distributed systems (FTODS). Taking into account the features of these building blocks, we propose an organization for FTODS. In FTODS, the algorithms needed for transferring files and synchronizing the concurrent activities of the computing modules – and for recovery – are ISO standard protocols. We propose the use of low-level voting and recovery algorithms that can run as a layer of software above the operating system to make the open distributed system an attractive environment for applying fault-tolerant techniques

Requirements to Secure End to End Privacy in IdLoc Systems: draft-xyz-pidloc-reqs-00.txt

International audienc