Warren G. Julian

Daylight measurement data: Methods of evaluation and representation

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 quantities is necessary. A number of formulae are proposed for the normalisation and analysis of direct beam, global and diffuse irradiances and illuminances and sky luminance distributions. Graphical representation of results is discussed and a graphical approach, the P-G-D diagram, is put forward as a solution for irradiance and illuminance data presentation.

Variation in near visual acuity with illuminance for a group of 27 partially-sighted people

This paper reports on the improvements in near visual acuity with increasing task illuminance for a group of partially-sighted people with various visual defects. The experimental method employed a technique which allows the easy transfer of experimental results to practical design. Comments are also made on the design of the visual environment for the partially sighted.

Lighting: an urgent case for a major research effort in architectural science

Abstract This paper examines a number of issues in lighting in the context of design and the first 30 years of architectural science. It observes that architectural sciences interest in lighting has mainly concerned the light-technical aspects of daylight and electric light and has tended to ignore the psychophysical. It also observes that there has been a reduction in lighting research and teaching in recent years and suggests that a major effort is needed to remedy this. Architectural science institutions should be the obvious homes for this research and teaching.

Comparison of real Sydney skies with model skies

This paper presents a comparison between some new models for representing sky luminance, as proposed by Kittler, Darula and Perez, and some typical skies recorded in Sydney, Australia. The results of this study show that these new models are most probably better suited to model skies that are clear or fully overcast as compared with the CIE standard sky models. Skies that have partial cloud coverage are typically more complex than can be modelled using standard models. In such cases special local models would have to be devised.

Sky luminance: Standard digital form for modelling

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.

Criteria for the Selection of Dimming Equipment in Schools

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.

Authors’ response to N Ruck

Dr Ruck highlights a major limitation of climatic data that even the World Meteorological organisation recognises. 1 One of the problems of meteorological observation of cloud cover is that it is a subjective visual process and the potential inter-observer errors involved have been known for some time, for example see Galligan. 2 This rror is greatest in the mid-range of cloud cover and varies with cloud type. It is exactly this problem that the method outlined in the paper hopes to overcome.

Writing Macintosh “applications” in APL

This paper briefly describes some features of a student enrolment and record system written for use on Macintosh PCs using APL.68000. The emphasis is on the development of the interface between the user and the APL file environment. The paper describes and illustrates the development of “applications” which use the Apple conventions and which appear like another Macintosh applications. This is achieved through the use of a series of powerful cover functions which access the Macintoshs primitives for file-handling, event-handling, windows, menus etc. and which use Quickdraw primitives for graphics and text output.

The use of APL.68000 access to the Macintosh quickdraw system for the productio n of shadows cast by buildings

This paper describes the considerations involved in predicting the shapes of shadows cast by buildings for any hour, day or month of the year and for any location on Earth. The power of APL is demonstrated in the general solutions possible for the problem irrespective of the shape of the building provided that it is composed of regular cylinders or prisms. Direct access to the Macintosh Quickdraw functions allows the production of graphical output of high resolution and using any of the available printing fonts. The system described makes use of Macintosh menus and dialogue boxes for data input and workflow control. The result is a system with an appearance similar to other Macintosh applications, such as, MacWrite, Word or MacDraw and the user is unaware of the presence of APL.

The use of APL primitives and function domains to produce general APL solutions to problems involving discontinuities

There are many mathematical problems where discontinuities or varying boundary conditions mean that a number of different solutions can apply, depending upon the domains of particular variables. In traditional algebra these solutions are usually listed as a set of solutions with the domains of the variables stated for each solution. In programming a similar technique is involved, using branching to select the expression to be evaluated depending upon the domains of the variables involved. By using APL, both as an algebra and as aprogramming language, single expressions for many such problems can be written (general solutions) which are valid for all variable domains. These solutions are generated using APL primitives to control either the domain of a function or its result. The paper will discuss the philosophy of the method and its application in simplifying the algorithmic solutions of problems involving restricted domains and discontinuities. Examples relating to the determination of shear forces and bending moments on isostatic beams and utilisation factors (used in electric lighting design) are used to demonstrate the generation of a general solution to a problem involving both restricted domains and discontinuities.