Showing papers by "AT&T Labs published in 1993"

Article comprising solder with improved mechanical properties

Abstract: New solder compositions which can have improved mechanical properties are disclosed. In a preferred embodiment, the solder comprises a matrix material and magnetically dispersed particles. A desirable dispersion of the magnetic particles in the matrix material, is accomplished by applying a magnetic field to the molten matrix material containing magnetic particles and solidifying it in the presence of the magnetic field. The particle-dispersed microstructures improve the mechanical properties of the solder composition. The improved solder composition can be made into a powder to be used in solder paste, cream or reshaped while substantially retaining the improved mechanical properties.

Optoelectronic cable connector

Abstract: A plurality of optical fibers (14-14E) are interconnected by using connectors each comprising an optoelectronic device (13-13E) adapted to be connected to an end of each optical fiber for converting optical signals to electrical signals and for converting electrical signals to optical signals. Each connector has a first contact (12-12E) having a cylindrical plug end and a cylindrical socket end located on a common axis and a transverse conductor (21) extending transversely to the axis (20) from the first contact and connected to the optoelectronic device of the connector. The plug end of each contact is adapted to fit snugly within the socket end of another first contact, whereby all of the contacts may be connected and arranged along the common axis. Each of the contacts is free to rotate with respect to other contacts to which it is connected; this permits the various optical fibers to extend in different radial directions from the axis. In a preferred embodiment, each connector further comprises second (23) and third (24) hollow cylindrical contacts surrounding the first contact (22). Hollow cylindrical insulators ( 26, 27) separate and insulate the first, second and third contacts, and appropriate slots permit transverse conductors (29, 31, 32) of the contacts to be connected to the optoelectronic devices (41). In this manner, each connector interconnects electrical ground and power lines, as well as the optical signal lines of the various optical fiber cables (40).

Teletraffic issues in ATM networks

Abstract: In recent years we have witnessed a rapid development of broadband digital communication technology, driven by the maturity of fiber-optic transmission techniques. Fiber-optic lines capable of transmitting data at a speed from 45 up to 155 megabits per second (Mbps) are already operational. In addition, transmission speeds as high as 3.4 gigabits per second (Gbps) have been achieved in research labs. Compared to the conventional Tl-speed (1.544 Mbps) network, a broadband fiber-optic network can serve not only the conventional data communication demands, but also provide sufficient bandwidth to facilitate new applications, such as voice and video. In today's telecommunication networks, however, traffic from these applications are still carried by separate, dedicated networks, e.g., the traditional telephony for voice, and cable TV for motion pictures. Work is currently being conducted by many organizations to explore the possibilities of integrating diverse communication demands (data, voice, and video) over a common broadband digital network covering a wide area,

Which patterns are hard to find

Abstract: The paper considers the exact number of character comparisons needed to find all occurrences of a pattern of length m in a text of length n using on-line and general algorithms. For on-line algorithms, a lower bound of about (1 + &) . n character comparisons is obtained. For general algorithms, a lower bound of about (1 + &) . n character comparisons is obtained. These lower bounds complement an on-line upper bound of about (1 ,+ &)) n comparisons obtained recently by Cole and Hariharan. The lower bounds are obtained by finding pattems with interesting combinatorial properties (these are the hard to find patterns). It is also shown that for some patterns off-line algorithms can be more efficient than on-line algorithms.