Generic Representation of Solid-Object Geometry for Genetic Search

Abstract: This paper examines the first stage of using genetic algorithms in design—how to encode designs as chromosomes. Generic representations capable of describing the geometry of any solid object to eliminate the unnecessary duplication of work at this stage are explored. A suitable low-parameter, spatial-partitioning representation is then proposed, using partitions consisting of six-sided polyhedra intersected by planes. Finally, the coding of the representation is examined, with the conclusion that allelic coding with control genes and user-definable, fixed-value alleles would provide the most flexible system.     

The Manager as Pirate: An Inspection of the Gentle Art of Bootlegging

Bootlegging is a special type of innovation involving covert research without the explicit approval of the responsible manager. It incorporates a dimension of secrecy as this research does not appear on project sheets drawn up by the management of firms. But it might also incorporate the dimension of conspiracy if the innovative activity is pursued by a research team, and perhaps with wider tacit support. Bootlegging exists as a phenomenon in a large number of companies. Interview findings suggest that the attitudes of management towards bootlegging are determined by prevailing perceptions of uncertainty and knowledge about the nature of decision processes.     

Global Environmental Change: Management Under Long-range Uncertainty

This paper gives an overview of social science challenges in global environmental research. After a sketch of backgrounds, the ‘social dilemma’ is introduced as a major research question. It is asserted that current uncertainties over global environmental change provoke innovative studies on risk behaviour and management of long-range, largely unpredictable, phenomena. Various illustrations of new research initiatives and directions are given.     

Applications of Telos

EuLisp has an integrated object system with reflective capabilities. We discuss some example applications which use these facilities to experiment with some advanced and powerful concepts, namely, finalization, virtual shared memory and persistence. A secondary goal is to attempt to illustrate the additional possibilities of metaobject programming over non-metalevel techniques.     

Plasma immersion ion implantation for SOI synthesis: SIMOX and ion-cut

We have demonstrated feasibility to form silicon-on-insulator (SOI) substrates using plasma immersion ion implantation (PIII) for both separation by implantation of oxygen and ion-cut. This high throughput technique can substantially lower the high cost of SOI substrates due to the simpler implanter design as well as ease of maintenance. For separation by plasma implantation of oxygen wafers, secondary ion mass spectrometry analysis and cross-sectional transmission electron micrographs show continuous buried oxide formation under a single-crystal silicon overlayer with sharp Si/SiO₂ interfaces after oxygen plasma implantation and high-temperature (1300°C) annealing. Ion-cut SOI wafer fabrication technique is implemented for the first time using PIII. The hydrogen plasma can be optimized so that only one ion species is dominant in concentration and there are minimal effects by other residual ions on the ion-cut process. The physical mechanism of hydrogen induced silicon surface layer cleavage has been investigated. An ideal gas law model of the microcavity internal pressure combined with a two-dimensional finite element fracture mechanics model is used to approximate the fracture driving force which is sufficient to overcome the silicon fracture resistance.     

Computer interface design: A user-centered approach

Enhancing the way people use computers to perform tasks has become a very important issue in interface design and human-computer interactions. When the concept of human-computer interaction first began to emerge it was commonly understood as the hardware and software through which a human and computer could effectively communicate (Laurel, 1990). This effective communication is also know as user-friendliness. The concept of user friendliness has recently been expanded to include various attributes and cognitive aspects of the user's needs and experiences. Focus should be on the user's experiences, expectations, preferences, and cognitive aspects in developing efficient and effective computer interface designs. It is the basic premise of this paper to emphasize using a user-centered design in developing computer interfaces.     

Deorthogonalization of ODS-CDMA QPSK by AM/PM Nonlinearity

When using a conventional demodulator, a sufficient condition to maintain ODS-CDMA codeword orthogonality is constant relative channel amplitude over the codeword duration. When transmitted over a memoryless, AM/PM nonlinearity channel, the chip-to-chip fluctuating amplitude of a composite ODS-CDMA QPSK waveform produces a chip-to-chip fluctuating phase that deorthogonalizes the ODS-CDMA codewords, resulting in an additional multiple access self-interference similar to that found in asynchronous DS-CDMA. For ODS-CDMA QPSK in an AM/PM nonlinearity channel, we utilize the Central Limit Theorem, derive, and evaluate: (i) an expression for the signal-to-distortion ratio at the demodulator output, (ii) an expression for the uncoded bit error probability, and (iii) an upper bound on the convolutionally-coded bit error probability. We find that the degradation to BER depends on both the AM/PM nonlinearity slope and the ODS-CDMA channel loading.