Upgrade Path Research Articles

A Phased Approach to Implementing DTV

There are many paths that can be taken during the transition from analog to digital television. Broadcasters must weigh the delivery of new services, such as high definition, multiplexed standard definition, pay television, and data broadcasting, versus budgetary and logistics constraints. Rather than jumping into a full-featured digital television (DTV) broadcast system, broadcasters may wish to consider the upgrade in phases. This paper discusses an upgrade path to delivery of new digital services that can be taken over four phases. At each phase, the broadcaster must build and install only a portion of the full DTV broadcast system; yet each phase also represents a milestone at which the broadcaster can deliver meaningful services.

High-speed point-to-point and multiple broadcast services delivered over a WDM passive optical network

Tailoring broad optical sources to the free spectral range of a waveguide-grating router, we show that multiple independent broadcast services can be delivered efficiently over a common wavelength-division-multiplexed passive optical network (PON). In addition to 1) delivering two independent video services, each comprising 80 digital video channels, we further exploit the periodicity property of the router to simultaneously deliver; 2) bidirectional 50-Mb/s baseband conventional PON service; 3) a limited (50 channel) digital broadcast video service; and 4) an individual 2.5-Gb/s bidirectional link to a "business" subscriber, demonstrating several distinct upgrade paths. Bit-error-rate performance and dispersion measurements are presented.

Broadband upgrade of an operating narrowband single-fiber passive optical network using coarse wavelength division multiplexing and subcarrier multiple access

We demonstrate an overlay of a broadband passive optical network (PON) on the same fiber network as an operating baseband digital system. The baseband system is modeled after current-generation narrowband PONs, and the two PONs can be operated simultaneously. The broadband PON incorporates coarse wavelength division multiplexing to increase the downstream bit rate, and subcarrier multiple access for the upstream upgrade. We examine the RF interference between baseband and subcarrier signals, and provide guidelines on channel spacing and means for accommodating differing power levels for the two signals. The broadband architecture described here provides a graceful upgrade path for providing advanced digital services on a PON without having to modify the network or terminal equipment used for providing narrowband services.

TOBASCO: an innovative approach for upgrading CATV fiber-coax networks for broadband interactive services

To introduce broadband interactive services in a fiber-coax CATV network with high splitting ratio, a high-density wavelength multiplexing upgrading strategy in combination with conventional TDMA techniques is presented. It features flexible network reconfiguration via wavelength reassignment at the fiber terminating network units, a high interactive services capacity per user, and improved network scalability. On the fiber part of the network the interactive channels are carried in baseband, time-multiplexed (in ATM) in a number of wavelength channels. The article gives an overview of the most distinctive characteristics of TOBASCO. The system architecture as well as the evolutionary upgrade path are presented. The implications of the flexible wavelength allocation scheme on the network topology and, in particular, dynamic assignment strategies are analyzed. Finally, the field trial to be carried out in Gent is discussed.

Digidesign Audiomedia III for Windows Computers

Digidesign's ProTools hardware and software products have earned a reputation among Macintosh users for intelligent design, top-notch sound quality, a modular upgrade path, and a host of features for audio professionals. In many audio production and post-production studios, ProTools has become the system of choice. With the release of its Audiomedia III hardware (hereafter 'AM III) and Session software, Digidesign is making many of those same benefits available to users of IBM-PCcompatible computers running the Windows operating system. The AM III consists of a single printed circuit card for Windowsbased Pentium computers using the PCI bus. The system includes Session installation diskettes for Windows 3.1 and Windows 95. (A version of Session for Macintosh computers is also available from Digidesign.) Other requirements include a minimum 75-MHz clock speed; 16 MB RAM minimum; an SVGA monitor and video card; and a fast internal EIDE or SCSI hard drive.

Reactor compatibility of the H-mode

H-mode operation presents challenges for ITER and for reactor application in the areas of performance, accessibility, sustainability and divertor compatibility. Some issues are more severe for ITER, while others are more problematic for an economic fusion reactor producing 3 MW of neutron flux to its walls. The problems that are more severe for ITER include the power requirements for the H-mode, and confinement uncertainties. Problems which are more severe for a reactor include capability for high operation, the role of the Greenwald density limit, and divertor compatibility. Within the present ITER concept, it would be very helpful to have a well defined upgrade path for the auxiliary heating systems, including options for strong profile control. The world fusion research programme should maintain a major focus on improving the reactor compatibility of the H-mode, with an eye to the special advantages of H-mode plasmas with strong shaping.

Building a digital library on ten thousand dollars a year

Describes the benefits of a low‐cost digital library server using an electronic mail interface. Suggests hardware and software configurations. Outlines a hypothetical budget and cost analysis for the first year of operation. Recommends a possible upgrade path. Suggests a “486” computer and v.34 high speed modem. Discusses the reasons for preferring the Linux adaptation of UNIX for the platform for this application. Recommends mail transport agent and outlines mail server programs available. The bibliography includes all online and printed references necessary to obtain and configure the software discussed.

Enriching the expressive power of security labels

Common security models such as Bell-LaPadula focus on the control of access to sensitive data but leave some important systems issues unspecified, such as the implementation of read-only objects, garbage collection, and object upgrade and downgrade paths. Consequently, different implementations of the same security model may have conflicting operational and security semantics. We propose the use of more expressive security labels for specifying these system issues within the security model, so that the semantics of a system design are precisely understood and are independent of implementation details. >

A Macintosh Interface for the Cameca Camebax-Micro Electron Microprobe

Over the past few years it has become apparent in our multi-user facility that the computer system and software supplied in 1985 with our CAMECA CAMEBAX-MICRO electron microprobe analyzer has the greatest potential for improvement and updating of any component of the instrument. While the standard CAMECA software running on a DEC PDP-11/23+ computer under the RSX-11M operating system can perform almost any task required of the instrument, the commands are not always intuitive and can be difficult to remember for the casual user (of which our laboratory has many). Given the widespread and growing use of other microcomputers (such as PC’s and Macintoshes) by users of the microprobe, the PDP has become the “oddball” and has also fallen behind the state-of-the-art in terms of processing speed and disk storage capabilities. Upgrade paths within products available from DEC are considered to be too expensive for the benefits received. After using a Macintosh for other tasks in the laboratory, such as instrument use and billing records, word processing, and graphics display, its unique and “friendly” user interface suggested an easier-to-use system for computer control of the electron microprobe automation. Specifically a Macintosh IIx was chosen for its capacity for third-party add-on cards used in instrument control.

A PROLOG simulator for interactive flexible manufacturing systems control

A simulation model of an in-line Flexible Manufacturing System has been built using the declarative computer programming lan guage PROLOG. The model is a vehicle for the study of dynamic responses of Flexible Manufacturing System control. Animation of system status and powerful user interaction are essential for this application. A simple but effective structure has been formulated in PROLOG as a core kernel of the simulator. The decision making process is modelled as a set of functional queues. Partitioning of the de cision functions permits modeling of complex peer-to-peer co ordinated decision making in non-trivial control environments. This offers many advantages over traditional manufacturing simu lation systems. The authors describe appropriate strategies for the realization of acceptable computational performance while retaining the powerful benefits of the PROLOG environment. The result is a practical operational system which features an incremental de velopment upgrade path, quick prototyping, fast and clearly understood code changes.

Migrating to System/38

The IBM System/38 was first introduced in 1978, with the latest model released in 1985. It provides an upgrade path for System/34/36 users and is an alternative to the 4300. The computer has a mandatory database with data dictionary. It supports interactive terminals and has complex security features.

An independent user's view of backplane bus standards

The general characteristics of the UK Independent Broadcasting Authority are examined in respect of its transmitter site construction and maintenance activities, and these are related to particular requirements in respect of processor-based equipment. Past experience with bus-based systems is discussed, with particular reference to Multibus I. The requirements derived from this experience are discussed and currently available bus systems are considered with a view to recommendations for use on future projects. Bus system inter-operability, and upgrade paths especially, are considered. The paper recommends that the best apparent couplings are between STE (PIO00), VME (P1014) and Futurebus (P896).