Journal of Light & Visual Environment
Online ISSN : 1349-8398
Print ISSN : 0387-8805
ISSN-L : 0387-8805
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Volume 17, Issue 2
Displaying 1-6 of 6 articles from this issue
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Papers
  • Lighting Design in Interreflective Environments Using Hopfield Neural Networks
    Kentaro TAKAHASHI, Kazufumi KANEDA, Takeshi YAMANAKA, Hideo YAMASHITA, ...
    1993 Volume 17 Issue 2 Pages 2_9-2_15
    Published: 1993
    Released on J-STAGE: February 25, 2011
    DOIhttps://doi.org/10.2150/jlve.17.2_9
    JOURNAL FREE ACCESS
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    This paper proposes a method for calculating luminous intensity distributions of multiple light sources taking into account both direct and interreflected light when a desired luminance distribution in a space is given. This inverse lighting problem is useful for designing rooms and tunnels. In our approach, a luminance distribution is specified instead of an illuminance distribution, because it is closely connected to the appearance of rooms and is used for lighting design in a tunnel. To calculate the intensity distributions of light sources quickly and robustly, the property of Hopfield neural networks that their energy converges to a minimum is exploited. The proposed method should greatly facilitate lighting design when used with rendering techniques such as the radiosity method. Several examples including lighting design in a tunnel are shown to demonstrate the usefulness of the proposed method.
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  • Relation between Helmholtz-Kohlrausch Effect, Purity Discrimination, and Go Function
    Yoshinobu NAYATANI, Hiroaki SOBAGAKI, Kenjiro HASHIMOTO
    1993 Volume 17 Issue 2 Pages 2_16-2_24
    Published: 1993
    Released on J-STAGE: February 25, 2011
    DOIhttps://doi.org/10.2150/jlve.17.2_16
    JOURNAL FREE ACCESS
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    Using the nonlinear color-appearance model, predicted are the four kinds of color-perception phenomena, which are the Go function studied by Evans, Munsell Values for different hues, purity discrimination, and the Helmholtz-Kohlrausch effect. The analysis confirmed that all the four phenomena are caused by the same common factor, the chromatic strength of spectral color stimulus reported by Evans in 1967.
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  • Effect of Operating Position on Photometric Performance of HID-Lamp Floodlights
    Tadahiro OTSUKA, Minoru =FUKUHARA, Tadashi MURAKAMI, Toru NOGUCHI
    1993 Volume 17 Issue 2 Pages 2_25-2_32
    Published: 1993
    Released on J-STAGE: February 25, 2011
    DOIhttps://doi.org/10.2150/jlve.17.2_25
    JOURNAL FREE ACCESS
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    Photometric performance of floodlights with HID lamps, a high pressure sodium lamp and a metal halide lamp, were determined through different methods and with the operating position varied. The position and the method had no effect on the photometric performance of a floodlight with a high pressure sodium lamp, whereas with a metal halide lamp, they did affect the luminous intensity distribution, leaving the luminaire efficiency intact. The results are considered to have been affected largely by the arc condition of the lamp used in the measurement. Consequently, for an accurate control of the luminous intensity distribution, correct selection of the optical system and of the measurement method are important in consideration of the operating position.
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  • Study on the Prediction of Illuminance by Daylight in a Retractable Domed Stadium
    Tomoko IKARI, Shunichi FUJII
    1993 Volume 17 Issue 2 Pages 2_33-2_40
    Published: 1993
    Released on J-STAGE: February 25, 2011
    DOIhttps://doi.org/10.2150/jlve.17.2_33
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    A daylighting calculation method for a domed stadium is presented. Based on this method, a computer program has been developed to predict illuminance distribution by daylight in a retractable domed stadium. Direct sunlight and skylight are considered as the daylighting sources in this program. Skylight model is based on the C.I.E. (Commission Internationale de l’Eclairage) Overcast and Clear Sky functions. For the purpose of examine the accuracy of the prediction by the computer program, the calculations were compared with the scale model measurements. A retractable domed stadium was designed and the 1:200 scale model was made. Illuminance measurements were carried out by setting the scale model under an artificial sky. The measured values were compared with the predicted values for the same conditions simulated by the computer program. As for this stadium, the predicted values agreed well with the measured values.
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  • Charging Tendency of Phosphors and Blackening Phenomena in Fluorescent Lamps
    Hidenori ITO, Yoji YUGE, Akira TAYA, Masaaki TAMATANI, Kenji TERASHIMA
    1993 Volume 17 Issue 2 Pages 2_41-2_49
    Published: 1993
    Released on J-STAGE: February 25, 2011
    DOIhttps://doi.org/10.2150/jlve.17.2_41
    JOURNAL FREE ACCESS
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    Long-term lumen maintenance of high-load fluorescent lamps is investigated using 3-band rare earth phosphors. The contact electric charging tendency of the phosphor is systematically varied by depositing colloids on the phosphor particle surfaces. For every phosphor system tested, the maintenance shows a maximum at a certain value in the charging tendency where the amount of mercury oxide absorbed on the phosphor is minimum. On the other hand, the depreciation of the phosphors themselves does not depend on the charging tendency. Furthermore, the charging tendency of mercury oxide exists near that for maximum maintenance. From these results, it is concluded that the difference in charging tendency between mercury oxide and a phosphor governs mercury oxide adsorption on the phosphor; the amount of adsorbed mercury oxide becomes larger with an increase in the difference causing significant lamp depreciation.
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