Engineering

Publication Search Results

Now showing 1 - 10 of 24
  • (1997) Altermatt, Pietro; Heiser, Gernot; Kiesewetter, Tobias; McIntosh, Keith; Honsberg, Christiana; Wenham, Stuart; Green, Martin
    Conference Paper
    An accurate numerical model is established for the simulation of buried contact cells in two dimensions. The physical parameters and the approximations are discussed as well as the procedures that lead to the foundations of the model. The model is applied to bifacial cells with three different rear surface configurations: (A) passivated by a thermally grown oxide, (B) by a dopand-induced floating junction, and (C) with a contacted junction. Especially when the cell is situated in a light-concentrating roof tile, configuration C performes far better than A and B. The two-dimensional effects of resistive losses in the semiconductor region of the cell are also discussed

  • (1997) Kuhlman, Burhard; Grauvogi, Manfred; Meyer, R; Hezel, Rudolf; Heiser, Gernot; Aberle, Armin
    Conference Paper

  • (1997) Kuhlmann, Burhard; Aberle, Armin; Hezel, Rudolf; Heiser, Gernot
    Conference Paper
    The Al/SiOx/p-Si MIS tunnel contact is an essential part of metal-insulator-semiconductor inversion-layer (MIS-IL) silicon solar cells. We experimentally determined the recombination properties (saturation current density J0 and ideality factor n) of the MIS contact in MIS-IL silicon solar cells fabricated at ISFH. Based on these measurements, it has been possible to resolve the contribution of the MIS contact to the total recombination losses in 1-sun illuminated MIS-IL solar cells by means of 2D numerical modeling. Furthermore, a 2D numerical optimization study is performed where the optimum width of the MIS contact fingers of advanced MIS-IL silicon solar cells is determined

  • (1997) Corkish, Richard; Puzzer, Tom; Sproul, Alistair; Luke, Keung; Heiser, Gernot
    Conference Paper

  • (1997) Elphinstone, Kevin; Russell, Stephen Michael; Heiser, Gernot; Liedtke, Jochen
    Conference Paper
    Single address space systems (SASOS) provide a programming model that is well suited to supporting persistent object systems. In this paper we show that stability can be implemented in the Mungi SASOS without incurring overhead in excess of the inherent cost of shadow-paging. Our approach is based on the introduction of aliasing into the SASOS model and makes heavy use of user-level page fault handlers to allow implementation outside the kernel. We also show how the demands of database systems for control over page residency and physical I/O can be accommodated. An approach to user-level implementation of distributed shared memory (DSM) coherency models is outlined.

  • (1997) Liedtke, Jochen; Elphinstone, Kevin; Schonberg, Sebastian; Hartig, Hermann; Heiser, Gernot; Islam, Nayeem; Jaeger, Trent
    Conference Paper
    Extensibility can be based on cross-address-space communication or on grafting application-specific modules into the operating system. For comparing both approaches, we need to explore the best achievalbe performance for both models. This paper reports the achieved performance of cross-address-space communication for the L4 microkernel on Intel Pentium, MIPS R4600 and DEC Alpha. The direct cost ranges from 81 cycles (Alpha) to 115 cycles (Pentium). Since only 2.5% of the L1 cache are required (Pentium) the average indirect costs are not expected to be much higher.

  • (1997) Zhao, Yong; Choi, Caroline; Zhang, Hua; Andrikidis, C; He, Ying
    Conference Paper

  • (1997) Epps, Julien; Dowd, Annette; Smith, John; Wolfe, Joseph
    Conference Paper
    The formants of speech sounds are usually attributed to resonances of the vocal tract. Formant frequencies are usually estimated by inspection of spectrograms or by automated techniques such as linear prediction. In this paper we measure the frequencies of the first two resonances of the vocal tract directly, in real time, using acoustic impedance spectrometry. The vocal tract is excited by a carefully calibrated, broad band, acoustic current signal applied outside the lips while the subject is speaking. The sound pressure response is analysed to give the resonant frequencies. We compare this new method (Real-time Acoustic Vocal tract Excitation or RAVE) with linear prediction and we report the vocal tract resonances for eleven vowels of Australian English. We also report preliminary results of using feedback from vocal tract excitation as a speech trainer, and its effect on improving the pronunciation of foreign vowel sounds by monolingual anglophones.

  • (1997) Ramadan, Ziad; Preston, Philip; Thong, Le-Gia; Chellen, Vija; Compton, Paul; Mulholland, Mary; Hibbert, D. Brynn; Kang, Byeong
    Conference Paper

  • (1997) Ramadan, Ziad; Mulholland, Mary; Hibbert, D. Brynn; Preston, Philip; Compton, Paul; Haddad, Paul
    Conference Paper