Warren Julian | The University of Sydney (original) (raw)

Papers by Warren Julian

Lighting Research & Technology, Dec 1, 2004

Lighting Research & Technology, Dec 1, 2001

One of the tasks in sky modelling is the determination of the location and amount of cloud covera... more One of the tasks in sky modelling is the determination of the location and amount of cloud coverage in the sky. Analysis using digital camera systems is possible but requires an automated method of separating sky images into clear sky and cloud regions. Two segmentation approaches have been used in this research, one based purely upon the colour characteristics of sky regions, the other a neural network approach using a wider range of variables. A convolution technique was developed to reduce classification errors prior to defining cloud outlines using polylines. Sensitivity analysis shows that this can be carried out efficiently with little loss of accuracy.

Architectural Science Review, Sep 1, 1973

Lighting Research & Technology, Sep 1, 1995

The luminance distribution of the sky dome provides basic information for various modelling tasks... more The luminance distribution of the sky dome provides basic information for various modelling tasks, including daylighting analysis and design, and for the creation of ultra-realistic computer-generated visualisations. To date there have been few tools to support the development and adoption of realistic luminance models for worldwide use. This paper presents a new approach to modelling sky luminance where explicit attention is paid to the presence of clouds and other obstructions to light available from the sky. A standard digital form (SDF) is proposed as a way of providing consistent representations of data from various sources (measured or empirical) that allows the data to be manipulated using a standard and consistent set of basic operators. These operators can be applied to build new (hybrid) models which can then be made available for use in simulation packages. Access to the SDF models is achieved through a standard set of functions which can be integrated into other user-written software.

한국태양에너지학회 학술대회논문집, Nov 1, 2002

Journal of light and visual environment, 2001

Lighting Research & Technology, 2000

... The SDF models derived from the SSLD models produce results very close to the defining empiri... more ... The SDF models derived from the SSLD models produce results very close to the defining empirical expressions. Table 1 shows a brief comparison of the zenith luminances produced for the subset of SSLD models t~ compare with the three example Sydney skies. ...

Architectural Science Review, 1982

This paper reports on a recent study undertaken into the use of automatic dimming equipment in sc... more This paper reports on a recent study undertaken into the use of automatic dimming equipment in schools in NS W, Australia. It looks briefly at the reasons why dimming must be considered as a means of energy conservation and considers the peculiar characteristics of school buildings. A discussion of the various methods that can be used for dimmer control is followed by a report on an experimental, full-scale study undertaken in a school in NS W. Practical considerations, such as, room design, zoning of dimmers, sensor location etc are then discussed with a brief comment on economic matters.

Architectural Science Review, 1975

Lighting Research and Technology, 2010

What an opportunity, I thought, on reading the invitation to write one of the first Opinion pages... more What an opportunity, I thought, on reading the invitation to write one of the first Opinion pages in Lighting Research and Technology. It was a pleasure to be invited because I have been a regular commentator on a number of lighting issues, including the apparent lack of impact of most of the last 30 years’ lighting research, that is, research outside of metrology, light sources and materials. Broadly, applications research has had little influence on practice, standards and, to some extent, the philosophy of lighting. However, this opportunity has turned out to be a very difficult task. What is the big idea, the big lost opportunity or the big problem that will change the lighting world? Like many others, I would say that uniform horizontal illuminance has been the problem. The concept is so well implanted into the minds of (technically competent) lighting designers and researchers that it is almost impossible to resist its gravitational pull. Along with this goes the naı̈ve idea that lighting calculations are precise; education on uncertainties and tolerances is suspended when illuminance calculations and measurements are undertaken. Most standards and codes of practice are silent on tolerances and there is no indication given in manufacturers’ data; all numbers are exact, presumably to the number of significant figures shown. It is amazing, too, that the decreasing visual difficulty of visual tasks has had no impact on lighting standards. No one reads a fifth carbon copy now because they don’t exist and most industrial tasks have become visually less demanding. Yet we doggedly stick to the great research byWaldram in the 1940s as the basis for today’s illuminance recommendations. Whilst lighting doesn’t encompass string theory and its prediction of possible parallel universes, lighting does have at least two others; one is daylight, usually limited to skylight and another, sunlight. The technology to explore these universes is certainly available but it seems that the most sophisticated software is mainly used to do what the lumen method can do in predicting average working plane illuminances, along with reams of output and supposedly photorealistic views of the appearance of a space. How can that be when no one knows what luminances or exitances produce ‘bright’ interiors? There is more that can be said, particularly about the consequences of the demise of publicly funded, non-university-based research over the last two decades and the effect on lighting research and research training. I think we are almost at the point of shifting our gaze from the lower horizontal plane to the vertical planes and the ceiling. Once that is done, the uniform horizontal illuminance universe will wane to be replaced by the brightness universe. That will allow visually meaningful lighting design and the ability to predict the visual effects of energy management strategies. In time, it will allow the daylight universes to coalesce with the brightness universe to bring lighting together, for the first time, as a unified science and technology, along with the benefits to society that will follow.

Lighting Research & Technology, 1992

... Waldram (44) suggests using the mean brightness of large parts of the visual field, defining ... more ... Waldram (44) suggests using the mean brightness of large parts of the visual field, defining this as within 10° of the point of regard. Bellchambers et al.(45) also consider 10° to represent the extent of the visual field which contributes to the adaptation luminance. ...

... abacus The ancient Greek calculating frame consisting of beads sliding on thin rods, still wi... more ... abacus The ancient Greek calculating frame consisting of beads sliding on thin rods, still widely used in ... and conditions of tests, the quantity of mixing water determines the strength of concrete, as long ... Usually the test is run for a deﬁnite number of strokes with a deﬁnite pressure ...

Architectural Science Review, 1979

... Warren G. Julian * ... necessitated by: improvements in lamps, luminaires and light control m... more ... Warren G. Julian * ... necessitated by: improvements in lamps, luminaires and light control materials; new research results; a realization of the role of daylight; and the ... The first Australian Code was issued during World War I1 as AS (E) CASOI-1942 [3] as a war-time emergency ...

Lighting Research and …, 1989

... AJ Shepherd BA, WG Julian BSc BE MSc(Arch) PhD DipBdgSc LFIES(Aust) and AT Purcell ... Julian... more ... AJ Shepherd BA, WG Julian BSc BE MSc(Arch) PhD DipBdgSc LFIES(Aust) and AT Purcell ... Julian suggests that observers' attention tends to be drawn to dark areas in the ... between 2000 and 5000 scotopic trolands (which corres-ponds approximately to daylight luminances of ...

Lighting Research and …, Jan 1, 1992

Summary The International Daylight Measurement Programme will generate a large amount of data fro... more Summary The International Daylight Measurement Programme will generate a large amount of data from distinct locations worldwide. To ensure comparability of results, data must be identified uniquely and standardisation of data analysis including the determination of derived ...

ARC Project A, Jan 1, 1998

Lighting Research and Technology, Jan 1, 1984

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