Excerpt of the publications
of De Luminæ Lab members De
Luminæ Lab members
have published several papers on international scientific
congresses, in particular PLEA and WREC.
Interpretation
models and their application for luminous ambience
ABSTRACT :
Quantitative information
from measurements or simulations of interior luminous ambiences yields
a large quantity of data. These data may be very useful to analyse the
performance and comfort of a luminous ambience in design or
rehabilitation and promote a controlled use of daylighting instead of
artificial light. However it is necessary to interpret these data with
terms accessible to architects.
The purpose of our work was
both theoretical and applied: we improved data collection and
interpretation methods of quantitative data on luminous ambience. We
then applied these methods to design a modified luminous ambience in an
existing space.
We had the opportunity to work in the
cafeteria of the "Galeries du Grand Palais" in Paris. We
improved the measurement method for luminance and chromaticities on the
interior opaque and glazed envelope of spaces in natural and mixed
lighting (both natural and artificial). We interpreted these measures
(a large number of quantitative data) in qualitative terms. On the
basis on these analyses, we followed the inverse path: we expressed the
concepts for modified luminous ambiences, then built these ambiences.
We could verify with measurements the correspondences between our
qualitative intentions and measured quantitative data. This
work gave interesting insights for the definition of criteria for the
analysis of luminous ambience. Keywords :
Daylighting, Luminous Ambience, Qualitative Expressions, Measurements.
Congress : PLEA2005 - Passive and Low Energy
Architecture.
Date : 13-16 November 2005, Beyrouth, Lebanon. Télécharger
: Interpretation models and their application
for luminous ambience
Will
it really be soft and calm, my luminous ambience?
ABSTRACT :
The intake and distribution of natural light in interior spaces are
imagined early in architectural design: placement of openings,
orientations and inclinations, depth of spaces, etc. are
defined during the first sketches. However, existing design aid tools
are ill adapted to this early
phase where the building is not completely defined.
In order to help overcome these difficulties, we propose to use the
models of buildings in design.
They are placed under an artificial or natural sky. Inside images are
displayed via micro-cameras on
a computer screen. The software computes correspondence between points
of the image and
luminance levels in the actual models. Knowing luminance in every point
of the interior envelope,
the software we are developing, analyses the luminous ambience on the
image.
The main
contribution of this work lies within ambience analysis on images,
expressed in qualitative and
quantitative terms. For example, the result of the analysis of a field
of vision is "calm and clear
ambience" or "tense and rather dark", etc. Definitions of such
qualitative terms, based on previous
works, are shown to users along with related quantitative and reference
data.
These methods help the use of natural light, hence of renewable energy.
It allows good use of the
natural luminous flux: to have enough but not too much (avoiding visual
discomfort and overheat). It
also allows architects to follow the aesthetic evolutions of the
ambiences they imagined.
Keywords : Visualisation, Luminous Ambience, Software Analysis,
Daylighting
Congress : PLEA2005 - Passive and Low Energy
Architecture.
Date : 13-16 November 2005, Beyrouth, Liban
. Télécharger
: Will it really be soft and calm, my luminous
ambience?
Simulation
of Luminaires in Radiance: Verification Method
ABSTRACT :
In the process of architectural design architects can use different
software tools for modelling and simulation. These programs allow them
to simulate imaginary buildings, and verify their intentions,
preferences and respect of norms, in order to bring the resulting
ambience closer to architects intentions. On the other hand, programs
follow strictly defined geometrical and physical laws, which give
quantitative accuracy to the project.
For modelling and simulation in architecture there is a great number of
different computer programs available on the market, such as AutoCAD,
3DStudio Max, PovRay, Radiance, etc. All these programs offer similar
possibilities for modeling of geometrical primitives, but their
capability to simulate luminous ambiance of the building is different.
Definition of luminous ambiance is rather complex, and it involves
description of artificial (luminaires) and natural (sun, sky) light
sources, building position and environment, and materials used for
building interior and exterior. Lighting design programs are software
tools for calculation and visualization of luminous ambiance.
Due to the complex nature of light, all lighting design
programs, in
the process of light modelling, involve some simplifying assumptions,
which lead to some amount of calculation inaccuracy.
The aim of this paper is to propose a method for evaluation of the
error introduced by computer simulation of luminaires. The method
compares luminaire simulation results from Radiance2 software against
results obtained from lighting calculation methods proposed by
“Illuminating Engineering Society of North America”
- IESNA.
Keywords : Luminous Ambience, Daylighting, Artificial Lighting,
Architecture, Interior
Measurements-Interpretation, Energy savings.
Congress : BCI'05 - Balkan Conference on Informatics
Date : 17-19 November 2005. Ohrid,
Macédonia. Download : Simulation
of Luminaires in Radiance: Verification Method
Measurement
and interpretation of luminous
ambience
ABSTRACT :
This paper presents part of a multidisciplinary work with three teams:
two laboratories of
psychology and a laboratory of lighting/architecture. We concentrate
here, within the
project, on activities on luminous ambience and focus on the
lighting/architecture part.
The problem we studied was: -
How is it possible to concisely express the variety of luminous
ambience qualities
on the basis of a large number of light measurements?
More precisely, in order to analyse the quantitative data collected
from measurements,
we intend to define interpretation models. The result of these
interpretation models
should be easily usable for further analysis and understandable by
architects. Architects
do not manipulate expressions such as luminance levels. In order to
express their
intentions for a luminous ambience, they use qualitative and
descriptive expressions.
-
On the basis on these interpretations, how can we change the existing
concept of
artificial lighting for a space in order to lessen energy costs, to
keep a good performance
of lighting and to improve the comfort and pleasantness of users?
More precisely, comfort and pleasantness are closely linked to
contrasts thresholds,
gradual ranges of luminance and chromaticities on the interior
envelope. Artificial
lighting is used by the general public and designers not only to reach
a sufficient level of
lighting on work surfaces, but also to increase or decrease contrasts
and gradual ranges
of luminance and modify the colour of the light on the interior
envelope in order to reach
a comfortable and pleasant ambience. In that respect, we can say that
the expenditure in
electric energy is also due to the fraction of artificial lighting used
to create comfort and
pleasantness of ambience.
To address these two questions, we have studied existing
luminous
ambience in two sites
in Paris. The spaces under study were rest areas. We defined the method
for light
measurement on the opaque and glazed interior envelope (with
luminancechroma and
luxchroma meters) in mixed lighting (both natural and artificial). We
interpret the
measurements in terms adapted to architects. We defined the concepts
for different
luminous ambiences and built these modified ambiences in the sites
themselves.
Keywords : Luminous Ambience, Daylighting, Artificial Lighting,
Architecture, Interior
Measurements-Interpretation, Energy savings.
Congress : WREC - World Renewable Energy Congress
Date : 22-27 May 2005, Aberdeen, United Kingdom.
Download : Measurement and interpretation of luminous
ambience
Luminous
ambience, quantitative/qualitative
data and subjective response
ABSTRACT
:
This paper presents several years of research in luminous ambience in
daylighting. It
began with works on the relationship between intuitive and quantitative
approaches for the
understanding of luminous ambience. We collected quantitative data from
measurements of
illuminance levels on glazed and opaque surfaces in interior spaces.
From these measures we could
build an interpretation related to the luminous ambience. They were
compared to what was
expressed by interviewed subjects in these spaces or to intentions
expressed by the architect during
the design when available.
At the end of this work, a first issue was: how could we explain that
comfort and pleasantness of an ambience may often be conflicting? We
investigated this question
and showed that comfort is not sufficient to express the quality of a
luminous ambience and that
some degree of “discomfort” may be needed by
individuals to feel an ambience as pleasant.
Confronted to the variety of answers given by people about luminous
ambience, we tried to
understand how subjective responses to a luminous ambience relate to
the dimensions of
personality. As this particular point of view seemed to have seldom
been investigated, we decided
to start a project specifically focused on this subject. The purpose of
this paper is therefore to sum
up this line of research, from quantitative measurements to dimensions
of personality.
Keywords : Daylighting, ambience, measurement, subjective response
Congress : First International Workshop on
Architectural and Urban Ambient Environment
Date : 6-8 February 2002. Nantes, France. Download :
Luminous ambience, quantitative/qualitative
data and subjective response
Dimensions
of personality in the responses to luminous ambiences
ABSTRACT :
In this multidisciplinary work, we propose a practical framework to
study the variability of
subjective responses to identical luminous ambiences (atmosphere). We
focus on the influence of
personality dimensions.
Architects build spaces for which they define functional
characteristics and an esthetical concept, while
considering the quality of ambiences. The success of a building depends
on the subjective perceptions and
the behavioural responses of users regarding these functionalities and
ambiences. In most works on
ambiences, the user is generally considered as an "average user"
(mister anybody). The importance and
variability of the subjective character of responses has often been
mentioned. However, we still do not
have effective indicators on the relationship between personalities and
the sensations of comfort and
pleasure in a luminous ambience.
The purpose of this work is therefore to study the relationship between
the perceptivo-cognitive
handling of luminance and chromaticities and the way social spaces are
occupied and used depending on
their luminous ambience.
We study the behaviour of subjects in a laboratory and on sites (in
rest areas). At the same time, we
study the luminous ambiences in these areas.
We obtain indicators on subjects: - 1) by
measuring perceptive sensitivity to luminous stimuli (ERP method, in
laboratory) with an electroencephalogram on 48 people in order to
detect high and low level
sensation seekers according to their sensations of pleasure
- 2) by observing the behaviour of the same
subjects in rest areas and by discussing with them with a
questionnaire.
We obtain indicators on existing luminous ambiences (with natural light
and artificial light to
complement it) in rest areas by measuring luminance, illuminance and
chromaticities on opaque and
transparent envelopes in these areas.
We then greatly modify luminous ambiences in these areas (by partially
covering windows and by
modifying artificial light). We then repeat the observations with the
same kind of subjects.
Keywords :
Congress : PLEA 2001 - Passive and Low-Energy
Architecture
Date : 6-9 November 2001. Florianopolis, Brasil. Download :
Dimensions
of personality in the responses to luminous ambiences
Comfortable
and/or pleasant ambience:
conflicting issues?
ABSTRACT :
We present here a theoretical study about the relationships between
comfortable and pleasant ambiences. The
notion of comfort is not sufficient for the study and design of
ambience. Ambience is defined here as the way
the environment affects a subject. Subjects are naturally affected by a
global ambience. However, for the
analysis, we distinguish between luminous, aesthetic, thermal,
acoustic…ambience.
Comfort definitions exclude the notion of tension and
psycho-physiological disturbance on subjects,
whatever its level may be. The question of pleasant ambience is
naturally not fully answered. However, one
way to define a pleasant ambience especially includes the notion of
tension on subjects affected by an
ambience. The case of the house on the cascade by F L Wright perfectly
illustrates this point. This house is
situated on a waterfall whose acoustic level is above all norms.
Therefore this house is not comfortable.
However, it is widely recognised and taught as a reference for its
pleasant ambience, especially for the
contribution of the acoustic ambience. In this case, the comfortable
and pleasant sides of ambience are
conflicting.
As modern technologies are improving, artificial lighting and
ventilation, for example, can lead to perfectly
comfortable ambience. However, it is widely recognised that natural
lighting and passive ventilation are more
pleasant.
We develop this discussion on the basis of the results of a study on
qualifications of luminous ambience and
on other theoretical and technical works. We believe that this
investigation is nowadays important because
the technological sides of ambience are improving: comfortable ambience
may be designed, but are they
pleasant? We think that a very global view on ambience is now needed.
Keywords :
Congress : PLEA 2000 - Passive and Low-Energy
Architecture
Date : 2-5 July 2000. Cambridge, United Kingdom. Download :
Comfortable
and/or pleasant ambience: conflicting
issues?
A
comparative analysis of luminous ambience designed for equivalent
functions  ABSTRACT
:
The first part of this work focused on the elicitation of links between
qualitative and quantitative approaches for luminous ambience in
daylighting. We
measured luminance and illuminance levels on glazed and opaque surfaces
in interior
spaces. We analysed and compared these measures and interpretations to
impressions
felt by subjects in the spaces, or to intentions expressed by the
architect during the
design of the project when available. This comparison has proved itself
very meaningful
and shows that many relations between the intuitive approach and
quantitative
measured data may be established.
In the second part, we performed a comparative analysis between
qualitative and
quantitative data for luminous ambience designed for equivalent
functions.
It helped us better define the meaning of the qualitative terms used by
subjects. It
also helped us enrich the quantitative point of view through the
definition of new
notions such as the rhythm of repetition of contrast levels or the size
of surfaces having
a particular level of luminance. This work can also be used to enrich
the language on
luminous ambience and be of great help on the classification of
luminous ambience. We
use this comparative approach in teaching, in our school of
architecture.
Beyond quantitative data, our method allows to perform an analysis
closer to
architects' needs and expressed in his language. This link between
qualitative and
quantitative allows to fill the gap between scientific technique and
architectural design.
It may be included in RADIANCE, to provide results related to
architects' intentions.
Keywords :
Congress : TIA
2000 - Teachers in Architecture
Date : 10-12 July 2000. Oxford, United Kingdom. Download :
A
comparative analysis of luminous ambience designed for equivalent
functions
Measurements
and qualification of luminous ambience in daylighting
 ABSTRACT
:
This paper is centered on the relationship between intuitive and
quantitative
approaches for the understanding of luminous ambience in order to
formalize criteria for the
classification of luminous ambiences.
We measured luminance and illuminance levels on
glazed and opaque surfaces in interior spaces and built a synthetic
scheme of these levels.
We then analyzed and compared these measures and their interpretation
to impressions felt
by several subjects in the spaces, or to intentions expressed by the
architect during the
design of the project when available.
This comparison has proved itself very meaningful and
shows that many relations between the intuitive approach and
quantitative measured data
may be established. The second part of the work deals with the
definition of criteria to
classify ambiences. They allowed us to prepare a computer tool, based
on neural nets which
will be used to help architects store and browse through a large number
of images.
Keywords :
Congress : PLEA
1999 - Passive and Low-Energy Architecture
Date : 22-24 September 1999. Brisbane, Australia. Download :
Measurements
and qualification of luminous ambience in daylighting
Interaction
between qualitative and quantitative approaches in the
teaching of architectural design 
ABSTRACT
:
In order to improve the understanding of daylighting by students in
architecture, we
seek a better integration between scientific and architectural
languages and we try to strengthen
the links between quantitative (knowledge on daylighting as a physical
phenomenon expressed in
mathematical terms) and qualitative (knowledge on daylighting as a
modifier of luminous
ambiance expressed in a descriptive way using natural language).
This will help students to reach
a better control of the phenomenon, to build their own criteria and to
apply them in the sketch
phase of architectural design. It may also be a basis for a
aiding-system for the design in the
sketch phase. We used fuzzy set methods and multivalued logicsto model
the building and its
environment and to structure knowledge taking architect’s
preferences into account. Keywords :
Congress : TIA
1995 - Teachers in Architecture
Date : 28-30 September 1995. Florence, Italy. Download :
Interaction
between qualitative and quantitative approaches in the teaching of
architectural design
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