Communication of multimedia data among multiple parties can be costly in terms of use of network resources if guaranteed quality of service is requested. We believe, however, that knowledge of the functional character...
详细信息
作者：
ERKER, GJDODDS, DEKRZYMIEN, WADavid E. Dodds was born in Saskatoon
Canada in 1945. He received the B. Eng. and MSc. degrees from the University of Saskatchewan in 1966 and 1968 respectively. He worked with Bell Northern Research (Ottawa) on PBX design in 1969 1972 and 1978. Since 1969 he has been with the University of Saskatchewan where he is currently Professor of Electrical Engineering. He teaches courses in electronics and communications and also presents short courses on the fundamentals of telephony. Current research interests are in data transmission signal processing architecture and frame synchronization for PCM and spread spectrum systems. He has been granted five patents relating to commercial products in delta-modulation telephone line interfacing and computer data transmission. In 1986 he was on sabbatical leave at BNR Inc. and worked with an ANSI committee on the standardization of FDDI-II a combined voice and data system. Mr. Dodds is a Registered Consulting Engineer in Saskatchewan. Witold A. Krzyden received his MSc. (Eng.) and Ph.D. degrees (both in Electrical Engineering) in 1970 and 1978
respectively from the Poznan Technical University in Poznan Poland. He was awarded the Minister's of Science and Technology Prize of Excellence for his Ph.D. thesis. From 1970 to 1978 he was a Research Engineer and Teaching Assistant and then from 1978 to 1980 an Assistant Professor of Electrical Engineering at the Poznan Technical University. In 1980 he won a Dutch Government Research Fellowship at the Twente University of Technology in Enschede the Netherlands for the year of 1980/1981. In the following year of 1981/82 he was a Research Assistant Professor there. From 1982 to 1986 he was an Assistant Professor of Electrical Engineering at Lakehead University in Thunder Bay Ontario Canada. In 1986 he joined the Univeristy of Alberta and Alberta Telecommunications Research Centre (now Telecommunications Research Laboratories or TRLabs) as an Associate Professor of Electrical Engineering. Currently he is a Professor of E
The 5.5 km range of the basic rate ISDN loop has been extended by using a negative impedance amplifier and by using a 2 wire/4 wire (2w/4w) amplifier. The negative impedance amplifier extends the range of the loop by ...
详细信息
The 5.5 km range of the basic rate ISDN loop has been extended by using a negative impedance amplifier and by using a 2 wire/4 wire (2w/4w) amplifier. The negative impedance amplifier extends the range of the loop by 1.0 km, whereas the 2w/4w amplifier extends the range by 1.5 km at the expense of increased complexity. As part of the amplifer design, a resistor/capacitor network has been developed which closely matches the characteristic impedance of telephone cable. Error rate tests have been conducted using various lengths of cable and an operating ISDN line.
This paper presents a method used to improve the current personnel evaluation procedures in a large company. The method is grounded on the semiotic analysis of stories justifying judgments. Categories and verbal value...
详细信息
This paper presents a method used to improve the current personnel evaluation procedures in a large company. The method is grounded on the semiotic analysis of stories justifying judgments. Categories and verbal values are represented by using concepts of fuzzy set theory. Particularly, a method is presented to measure the membership value of an individual in a predefined fuzzy category.< >
Optical second harmonic generation (SHG) is a highly surface‐sensitive probe for studying crystalline Si surfaces because the inversion symmetry is broken and electric dipole optical SHG processes forbidden in the bu...
Optical second harmonic generation (SHG) is a highly surface‐sensitive probe for studying crystalline Si surfaces because the inversion symmetry is broken and electric dipole optical SHG processes forbidden in the bulk are allowed. The polarized optical SHG from a perfectly oriented Si surface is inherently anisotropic, varying periodically as the in‐surface projection of the polarization vector of the incident laser is rotated about a normal to the surface. The harmonic contributions to the angular anisotropy from the surface are characteristic of the surface bonding, and are modified by misorientation, chemical termination, as well as thermal treatments. This paper reviews the results of our previously reported optical SHG studies on Si(111) wafers with misorientations of 0°–5°±0.5° in the [112̄] direction for Si–H or Si–O terminated surfaces. Azimuthal anisotropy data are compared with an empirical model for the SHG intensity that is based on (i) the nonlinear response of anharmonic oscillators, and (ii) a phenomenological theory of azimuthal anisotropies expected for different surface orientations. This model is used as a framework for estimating ’’effective‘‘ resonance energies from single wavelength experiments, and in particular, for providing insights into the microscopic mechanisms that can contribute to the changes in these resonance energies with respect to different processing conditions. For example, important differences between thermally grown and plasma‐oxidized interfaces are identified, and correlations between SHG and electrical performance of the Si–SiO2 interfaces are discussed.
Current user interface builders provide only low-level assistance, because they have knowledge of neither the application, nor the principles by which interface elements are combined effectively. We have developed a f...
详细信息
ISBN:
(纸本)9051991339
Current user interface builders provide only low-level assistance, because they have knowledge of neither the application, nor the principles by which interface elements are combined effectively. We have developed a framework that unites the knowledge components essential for effective user interface presentation design. The framework consists of an application model (both a data model and a control model), a design process model that supports top-down iterative development, and graphic design knowledge that is used both to place dialog box elements such that their application dependent logical relationships are visually reinforced and to control design symmetry and balance. To demonstrate the framework's viability, we have constructed a tool based on encapsulated design knowledge that establishes high-level style preferences and provides expert assistance for the dialog box presentation design and menu structuring.
A specific class of multimedia applications is expected to be of importance for future communication networks: multi-party interactive multimedia (MIM). Based on the isolation and characterization of MIM applications,...
详细信息
A specific class of multimedia applications is expected to be of importance for future communication networks: multi-party interactive multimedia (MIM). Based on the isolation and characterization of MIM applications, concrete network support requirements are derived. The varying degree of connectivity, the vastly different sizes in terms of participants and the reliance on a guaranteed quality of service make MIM support a difficult problem. Starting with the definition of multimedia communication abstractions, principles of solutions are sketched. For an important subclass of applications, a particularly efficient and practicable alternative implementation based on half-duplex channels is introduced. Interfaces at both the transport and network layers are also considered.< >
Most of the solutions proposed to support guaranteed performance communication services in a packet-switching network adopt a connection-oriented and reservation-oriented approach. In this approach, the resource alloc...
详细信息
Most of the solutions proposed to support guaranteed performance communication services in a packet-switching network adopt a connection-oriented and reservation-oriented approach. In this approach, the resource allocation and route selection decisions are made during connection establishment on the basis of the current resource availability and real-time network load, and are usually kept for the duration of the connection's life time. However, such an approach shows two major limitations: first, the communication service provided is usually fixed, with limited or no capability of adapting to dynamic changes in the clients' requirements; second, a low utilization of the network may be observed. In the paper, the authors present a flexible management scheme that allows graceful adaptation of guaranteed performance service connections. Mechanisms have been devised to allow changing of the trade and performance parameters of a real-time connection during its lifetime. These mechanisms, together with an adaptation policy, can make more efficient use of the network resources by performing cooperative, consenting, high-level multiplexing. the authors distinguish between two types of adaptation: client initiated adaptation and network initiated adaptation. They give examples for both types and present results from simulation experiments to show the effectiveness of the approach.< >
暂无评论