TAKING SOUNDINGS A COMPOSERS` INVESTIGATIONS INTO TECHNOLOGIES OF NAVIGATION

3 03 2009

By YOLANDE HARRIS

Taking Soundings places musical composition and sound art in a space of navigation and landscape. It suggests that technologies of navigation contribute to forming our relationship to the natural environment. Through the media of sound, moving image and space, the research contemplates the artistic implications of navigation through a technological position of motion, instability and noise. This empirical approach highlights the contrasts between a bodily experience of a physical environment and technologies of invisibility and intangibility. Sound, in the meeting of its physical and musical guises, is the primary catalyst.

As a composer I advocate that musical composition can benefit from stepping outside its own formal systems in order to investigate how sound can operate within the larger context of image and space. Beginning with the musical score, which does not contain sound but encodes potential interpretations by a performer within its notation, I use this interpretative gap between image and sound to drastically expand the idea of the score. Building on my other formal training in architecture and moving image, I initially looked into sound in relation to landscape and new technologies, then focused on navigation techniques. Much like a score, these presented spatial and temporal concepts with a direct physical relationship to the person navigating. It also created a discourse around the map, chart, trace and the various levels of notated or linear images in relation to the environment.In attempting to chart as carefully as I can an illusive area between sound, image and space as we actively make it, or physically compose it, I take on the complex influences of technologies.

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THE COSMOPHONE PLAYING WITH PARTICLES, THE COSMOS AND SOUNDS

3 03 2009

By  CLAUDE VALLÉE, http://cosmophone.in2p3.fr

 

THE INFINITELY SMALL, THE INFINITELY LARGE AND THE HIGH ENERGY DENSITY FRONTIER

Fundamental physics explores areas of nature which are more and more distant from common sense and usual representations of reality. In the past decades, high energy particle accelerators have revealed a new world of sub-atomic particles and forces which govern the behaviour of matter. These objects are described within the frame of quantum mechanics and Einstein relativity, which dilute the usual concepts of determinism, localisation, time and energy. It was recently recognised that the properties of sub-atomic particles are intimately related to the behaviour of the Universe in its very first moments. Within the Big Bang model, now corroborated by numerous observations, the energy density was so high in the first fraction of second that all kinds of sub-atomic particles existed together, forming a gas of matter, anti-matter and radiation interacting in the same way as they do in present high-energy accelerators or violent cosmic phenomena like quasars or super-novae. This conjunction of cosmology and particle physics is one of the most striking trends of present fundamental research.

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ARTISTIC PROPOSALS ON CULTURAL APPLICATION OF JEM 2009 ISS ART EXPERIMENT PROGRAM

2 03 2009

By TAKURO OSAKA

“If I were to create art in space, it would be composed of light.” Souichi Noguchi, the Japanese astronaut, commented after the STS-114 mission to artists at a debriefing session held at Tokyo National University of Fine Arts & Music in October 2005. He stated that through his visual experience in outer space, he felt that light had an artistic
potential in space. The statement was a great inspiration for me as a creator of light art and as a professional who conducts studies on space and art, and gave me the opportunity to write this paper. (Mission Debriefing Session by Astronaut Noguchi, 2005)

In 2008, when the Japanese Experiment Module (JEM) “KIBO” will be docked to the ISS (International Space Station), the pilot mission for artistic experiments will begin. Prior to this mission, since 1996, JAXA (Japan Aerospace Exploration Agency) has been conducting research on the effective application of cultural-social sciences to JEM, and since 2000, has carried out experiments pursuing the theme “Potential of Art in Space”.

The artistic experiments in the space shuttle by astronauts Doi (STS-87 Mission, 1997) and Noguchi (STS-114 Mission, 2005) are from this project. The present paper will report on the artistic experiments that started in 2000 and introduce the designs of the art pilot mission to be launch in 2008, and discuss the potential of art in space.

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SONIC EUKARYOTES: SONOCYTOLOGY, CYTOPLASMIC MILIEU AND THE TEMPS INTERIEUR

2 03 2009

By SOPHIA ROOSTH

At the beginning, the whole body or organism raises up a sculpture or statue of tense skin, vibrating amid voluminous sound, open-closed like a box (or drum), capturing that by which it is captured. We hear by means of the skin and the feet. We hear with the cranial box, the abdomen and the thorax. We hear by means of the muscles, nerves, and tendons. Our body-box, stretched with strings, veils itself within a global tympanum. We live amid sounds and cries, amid waves rather than spaces the organism moulds and indents itself…I am a house of sound, hearing and voice at once, black box and sounding-board, hammer and anvil, a grotto of echoes, a musicassette, the ear’s pavilion, a question mark, wandering in the space of messages filled or stripped of sense.…I am the resonance and the tone, I am altogether the mingling of the tone and its resonance.i

–Michel Serres

That we have no ears to hear the music the spores shot off from basidia make obliges us to busy ourselves microphonically.ii

–John Cage

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INSECTS, TREES, AND CLIMATE: THE BIOACOUSTIC ECOLOGY OF DEFORESTATION AND ENTOMOGENIC CLIMATE CHANGE

21 02 2009

By DAVID DUNN and JAMES P. CRUTCHFIELD

Accumulating observational evidence suggests an intimate connection between rapidly expanding insect populations, deforestation, and global climate change. We review the evidence, emphasizing the vulnerability of key planetary carbon pools, especially the Earth’s forests that link the micro-ecology of insect infestation to climate. We survey current research regimes and insect control strategies, concluding that at present they are insufficient to cope with the problem’s present regional scale and its likely future global scale. We propose novel bioacoustic interactions between insects and trees as key drivers of infestation population dynamics and the resulting wide-scale deforestation. The bioacoustic mechanisms suggest new, nontoxic control interventions and detection strategies.

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THE COSMOPHONE: PLAYING WITH PARTICLES, THE COSMOS AND SOUNDS

15 01 2009

by CLAUDE VALLEE

THE INFINITELY SMALL, THE INFINITELY LARGE AND THE HIGH ENERGY DENSITY FRONTIER

Fundamental physics explores areas of nature which are more and more distant from common sense and usual representations of reality. In the past decades, high energy particle accelerators have revealed a new world of sub-atomic particles and forces which govern the behaviour of matter.  These objects are described within the frame of quantum mechanics and Einstein relativity, which dilute the usual concepts of determinism, localisation, time and energy. It was recently recognised that the properties of sub-atomic particles are intimately related to the behaviour of the Universe in its very first moments. Within the Big Bang model, now corroborated by numerous observations, the energy density was so high in the first fraction of second that all kinds of sub-atomic particles existed together, forming a gas of matter, anti-matter and radiation interacting in the same way as they do in present high-energy accelerators or violent cosmic phenomena like quasars or super-novae. This conjunction of cosmology and particle physics is one of the most striking trends of present fundamental research.   

THE COSMOPHONE

The cosmophone is a tentative to reveal this close connection between the infinitely small and the infinitely large in a sensuous way, by detecting and imaging the continuous flow of elementary particles originating from our entire galaxy: cosmic rays. Figure 1 gives a general sketch of the concept and Figure 2 a schematic view of the technical implementation.

COSMIC RAYS

Our planet is continuously bombarded by cosmic rays made of protons and atomic nuclei which are emitted from throughout our galaxy. These particles can be accelerated to very high energies when they encounter gases in expansion as produced by super-novae. They are confined within the galaxy by the galactic magnetic field and travel typically several millions of years before reaching the earth. As they hit the upper atmosphere, cosmic rays create avalanches of elementary particles. The most penetrating of these are “muons”, which can reach sea level.  A muon is a type of heavy electron not found in ordinary matter because of its very short life time.  The human body is insensitive to muons, even though several muons pass through us every second. Muons can show up in three ways: either individually (the most frequent case), or as a bunch originating from a particularly energetic cosmic proton, or as an electromagnetic shower of electrons, anti-electrons and photons in case the muon interacts with matter above the installation.

cosmos_2 PARTICLE DETECTION

The cosmic particle detection is based on standard techniques used for decades in high energy particle physics. Muons are detected by the very faint bluish light they generate in plastic scintillator strips deployed as two detector arrays located on the ceiling and the floor of the installation. The tiny light flashes are converted into short electric pulses by photo-multipliers. Parasitic noise from terrestrial natural radioactivity is discarded using the fact that muons travel at a speed close to the light speed, and therefore cross the installation quasi-instantaneously: a muon signature consists in two sensors hit simultaneously on the ceiling and the floor.  The positions of the hit sensors give the direction of the muon trajectory in space. In case of electromagnetic showers, several contiguous sensors are hit in both detector arrays. The electromagnetic shower size variations are an essential additional source of randomness in the detected phenomena. The signals of all detected phenomena are readout by a fast data acquisition system, converted in MIDI format and transmitted almost instantaneously to a real time sound synthesis system.

SOUND SYNTHESIS

The aim of the sound synthesis is to instantaneously materialise the trajectories of cosmic particles in space as they move through a given point, and to offer additional features to composers for special effects. The sounds are produced digitally in real time by a computer which operates two arrays of loudspeakers directly hooked up to the detectors. Sound synthesis is technically handled with the program MAX-MSP, which is interfaced to the cosmic particles input parameters

 cosmos_2b through a more general framework, allowing the composer to drive the music as function of the occurrence of cosmic phenomena. The generation of sounds in three-dimensional space makes a heavy use of the laws of psycho-acoustics, but full freedom remains to the composer to interpret the cosmic phenomena in a personal way and let his imagination wander.

ARTISTIC  CONTEXTS

The cosmophone can be declined in various artistic contexts, ranging from museum installations to more general implementations serving as framework for public artistic shows.

MUSEUM INSTALLATION

As a museum device, the cosmophone acts as a three-dimensional installation whose goal is to materialize the features of the detected phenomena in the most evocating way. As an example Figure 3 gives a view of the cosmophone built for the Cité des Sciences et de l’Industrie in Paris. In such an installation isolated muons are reproduced by activating the two loudspeakers associated to the top and bottom hit detectors. The sound is moved in space from the muon’s entry point down to its exit point, while shifting its frequency as would occur with a real moving source (Doppler effect). Impact sounds are added at the entry and exit points to improve the spatial localisation of the trajectory.  Electromagnetic showers are materialized by trickling and streaming envelopes whose texture can depend on the size of the showers.

In such an installation, the choice of sound as a medium is essential for several reasons. First of all, sound is transmitted as a mechanical vibration, providing a direct contact with the distant phenomenon. The moderate ability of the ear to locate sound sources is also well matched to the rather coarse space sampling allowed by simple particle detectors and loudspeakers. Finally the present sophistication of numerical sound synthesis techniques allows a flexible real-time three-dimensional imaging of particle properties. Such an environmental reproduction is essential to the emotional impact of the physics phenomenon.  These principles could be extended to the reproduction of many other physics processes.

cosmos_3 ARTISTIC SHOWS

The cosmophone can serve as a general framework to public artistic shows involving composers, choregraphers or other artists. Such a large cosmophone, covering an area of up to 100 squared meters and initially built for the 50th anniversary of CERN (the European Centre for High Energy Physics located in Geneva), is now exploited by the Music Company UBRIS STUDIO led by Jacques Diennet.  Potential performances include pure electronic compositions, mixed compositions with musicians improvising within the cosmophone, or even dancers acting as function of the detected phenomena. The public can stand either within the cosmophone, or outside like in front of a conventional stage.  In all cases, the cosmophone offers artists an opportunity to express how the extreme worlds of sub-atomic particles and cosmic phenomena stimulate their imaginations.

The first use of the cosmophone in such a context was pioneered by Jacques Diennet at the 50th anniversary of CERN in October 2004. In this occasion his piece “La Paix des Etoiles N0 2” was created in Geneva with the large cosmophone exploited by UBRIS STUDIO. This is a 10 minutes pure electro-acoustic composition which attacks one of the central question of music: the control of the musical process. In the present case and in line with the principles initiated by John Cage, the spacialised sound effects are driven by the real time random occurrence of cosmic phenomena, within a pre-defined sequence programmed by the composer.      

UBRIS STUDIO also offers artists the possibility to exploit the cosmophone within their own aesthetic principles. An opportunity to extend the artistic use of the cosmophone was given by the “Groupe de Recherche et d’Improvisation Musicales” (GRIM) in Marseille, where several concerts and workshops were organised in January 2006. In this occasion three new pieces were created: one electro-acoustic piece from Michel Pascal, “Leçons de choses”, combining a pedagogic text on cosmic particles with sound effects, and two pieces involving for the first time live musicians interacting with the cosmophone. The first one, “Téléphone maison, variation cosmique sur un theme populaire” from Pascal Gobin, presents a brass ensemble which improvises within the cosmophone as function of the detected phenomena. In the second one, “Intraçables N0 1” from Jean-Marc Montera, the words of a poem from late writter Tarkos are scattered apart within the room by the random occurrence of cosmic muons, whereas Jean-Marc Montera improvises on a traditional Corsican guitar, a cetera.  Figure 4 shows a photo of this performance during one of the GRIM concerts.

The positive reaction of the public as well as of the press to these exploratory attempts have confirmed the relevance of the artistic exploitation of the cosmophone, and UBRIS STUDIO is presently developing new partnerships for further projects.

cosmos_4 SUMMARY

The cosmophone is a meeting point of advanced basic sciences (astrophysics and particle physics), new technologies (real-time digital sound synthesis and sound spacialisation) and contemporary art (environmental music and systems), fields where mutual fertilisation offers a potential source of innovative developments. By putting spectators at the junction of the infinitely small and the infinitely large, the cosmophone brings the listener into direct contact with our galaxy and the violent phenomena that take place there, creating a new world of stimulation to artistic creation. 

http://cosmophone.in2p3.fr





HERE IS NOW AND THERE THE SOUND OF THE LAND: GROUND-BREAKING

3 10 2008

by PAUL ADDERLEY and MICHAEL YOUNG

SCIENTIFIC AND SONIC PERCEPTIONS OF THE AFRICAN SAHEL

Societies are often required to react to extreme events that arise through either anthropogenic or natural processes. Such extremity might be measured is in terms of its immediacy and intensity; it demands comprehension against understood norms. For example, our present-day debate on future climatic change is driven by scientific assertion, reinforced by evidence gathered from both instrument and indirect proxy measurements, whilst the varying societal responses are predicated by everyday cultural experiences. In contrast, places considered to offer experiences at the boundaries of or outside the everyday, e.g. hot and cold deserts, provide a different conception of extreme. In this conception, change and the rates of change typically lack context, validation and position within everyday norms. Consequently, it is within such surroundings that the greatest tension occurs between the perception of place and rates of change. While the methodologies of science and art practice are often respectively considered positivistic and non-rational, both are in fact able to investigate the extreme in this context. Whether or not such characterisations are legitimate, the obvious epistemological differences both illuminate and problematise our understanding. In this paper we describe a real-time generative installation commissioned from the authors by the UK Research Councils called Ground-breaking: Extreme Landscapes in Grains and Pixels that attempts to explore and test these differences . Further examples are available at http://www.ground-breaking.net.

This work offers context and potential validation about change and the rate of change of an extreme environment: this is evidenced through scientific analysis of landscapes and soils and is translated, in a process of critical evaluation, to create an audio-visual installation. The installation seeks to convey cultural imprints left by societal responses to change experienced in a marginalised area, the African Sahel. By considering a landscape that is both extreme and has long-standing cultural activity, a narrative is developed. To borrow Barthes’s terminology (Barthes, 1977), the data from scientific analysis provide functions to the narrative; they are indices to the landscape and to human conditions. These data also connote actions that may be anthropogenic or environmental (such as changes in land management, house building, flooding and desertization). A narrative emerges from the exploration of these data, in which a sequence of actions is deduced from functional descriptions of physical objects, which are in turn offered for evaluation and exploration in sonic and visual forms.

CONTEXT AND INVESTIGATION

The fertility of soil is fundamental to the long-term sustainability of human societies and is a source of, and sink for, materials used to sustain human existence. Soils may retain the imprint of cultural activities, presenting an opportunity to examine how past societies managed their surrounding landscapes. Soils can act as a record of past cultural activities; the examination of such soils – cultural soils – is a major element in the Ground-breaking installation. 

The soil materials referred to by the installation were sampled from the West African Sahel at a village called Tiwa located in the lacustrine plain of Lake Chad in Northern Nigeria (Adderley, et al., 2004). This region has experienced extremes of flooding and drought throughout history that may have displaced the human population. The village has dwellings constructed from mud-brick and thatch, surrounded by fields. Samples were taken from a pit dug close to the village. This area is subject to intense land management and receives cultural debris washed-in by seasonal rains. The materials were sampled intact with the spatial organisation of the soil maintained through processing and examination in the laboratory. The soils were found to span a 10,000 year period that includes the onset of human settlement in the Lake Chad plain c. 4000 years ago (Connah, 1981). For the Ground-breaking installation these materials were analysed to produce data streams suitable to cross-disciplinary interpretation. An examination of large areas of the samples allows a virtual exploration of microscale features. By using the latest digital image-analysis methodologies, a quantitative examination of the materials identifies objects that provide discrete cultural signals. These objects can then be classified and spatially related and in turn be used to develop a sonic narrative drawing upon both the measurements and their interpretation as cultural signifiers.

To allow microscopic viewing, the soil materials were treated to produce glass-mounted thin-section samples. The samples were dried, impregnated with resin, mounted, ground and polished to a uniform thickness of 30 µm. At this thickness grains of quartz mineral are translucent. The thin-section samples were observed with a microscope and images captured with a sequence of different illumination methods, each producing a different resultant image. For example, the oblique incident reflected light image typically shows dark images with colours that can be interpreted as related to cultural activities; specifically burnt materials, such as pieces of fired clay and partially combusted fuel materials, show clearly as ruby reds and orange colours. 

From eight microscope slides a total of thirty-two areas were analysed. For each sample area a large-scale calibrated image was made, repeated for all four illumination methods. These images were examined using image-analysis techniques (Russ, 2006; Adderley et al., 2002), each group of objects representing the imprint of a different cultural event: construction and destruction of buildings, soil disturbances such as cultivation and periods of flooding. Each object in the image was identified and its size, shape and location analysed. With the object defined as a mass of contiguous pixels that satisfy the segmentation criteria of specific colour properties, the object’s area is given by counting the number pixels whilst the outer edge of the mass of pixels is the object perimeter. Holes are identified as pixels outside the segmentation criteria yet bounded by those that are. Shape was estimated by measuring parallel tangents – Feret measurements – at 360 positions around each object (Russ, 2006). The fractal dimension of each object, a derived measure of shape, was calculated from the area and perimeter relationship (Mandelbrot, 1977). By considering the centre of the object as the point with the maximum distance from any point on the perimeter, a set of co-ordinates for each object within an image can be determined. There is therefore a data set for every identified object comprising {x,y} spatial coordinates and a descriptive list; object area, perimeter, count of the holes in the object, Feret mean, fractal dimension and colour hue, saturation and intensity. These and the 10,000 year temporal data form the precursors for the implementation and structure of the installation.

IMPLEMENTATION OF THE GROUND-BREAKING INSTALLATION

The macrostructure of the installation is guided by a master clock that represents the 10,000 years. The equivalent time interval executed by the installation system varies on each cycle, which denotes interpolated data describing the lake-level of Lake Chad at decadal intervals. The levels are indicative of three states; flood, drought or human-populated. These data are interpreted as a probability function that influences the generative processes of the installation. Adaptive probability systems have been applied in other recent work by Young (2007).

The visual component comprises a library of on-site photographs and the thin-section images of soil samples. At irregular time intervals a thin section is selected and images, along with soil data, are loaded. The choice is randomised, restricted to the time period indicated by the current position of the master clock. Images are deployed in cross-fading combinations to allow for complementary perspectives of colour and detail. Real-time visual behaviours are related to the lake-level state: drought (minor colouration effects), flood (flowing progression between data points,) and human population settlement (onsite photographic material actively interspersed). Sound materials are controlled similarly, such that the most clearly referential sounds  (i.e. environmental, voices, music) are more likely when relevant to the historical scale. Audio material is generated from the soil data’ each object’s descriptors (area, perimeter, Feret, etc..) are mapped to the sound synthesis algorithm. as long as the current image selection is in view.

The generation of sound from non-musical data is well established (Scaletti, 1994). Pre-existing wave functions are easily susceptible to sonfication, by a direct mapping of function to synthesis. This approach can be contrasted to higher level mapping strategies, in which an input parameter set is made congruent with the requirements of a specific sound generating system (Hermann & Ritter, 1999). Parameter mapping strategies have been classified as one-to-one, divergent or convergent (Hunt & Wanderley, 2002), indicating the possibilities for data to be directly translated, directed to a multiplicity of parameters, or condensed to fewer dimensions. Designer intervention – whether intentional or not – is common in this mapping process. In all these cases, the broad aim of sonification is to render complex data susceptible to analysis. A common question arises from the absence of time information in the data itself, and the consequent need for data to be linearised in time as a stream of discrete events. Given that temporalisation is, in effect, sonification, some form of creative decision-making is unavoidable, and must to some extent be predicated on the desired outcome of the investigation.

In Ground-breaking, the mapping of data to sound parameters is arbitrary but consistent in any one cycle of the 10,000 year history. For each iteration of the master cycle, the mapping is assigned autonomously by the system with no creative intervention from a user. There are seven data parameters and over twenty sound synthesis parameters, so this reshuffling is decisive in pre-determining the vocabulary and behaviour of sounds. Two synthesis techniques are employed; subtractive synthesis (multi-band filtered noise) and granular synthesis (or granular reconstruction, the production of extensive and timbrally-rich sound events by the proliferation of tiny sonic fragments). Granular methods offer the possibility of clear sonic reference, and more abstract material, depending on the content, duration and processing of individual grains. Sonic parameters include the frequency content, bandwidth and harmonicity of filter banks, the size, content, amplitude, post-processing of grains. Grain content is critical: this is obtained from a library of recorded sounds stored by the system, tagged with descriptors denoting their referential content (such as water, work, environment, human voice, music) and sonic character (loudness brightness, roughness, pitch-noise). The tags are assigned as sound parameters, so sound sources are read into the granular synthesiser as a basis for subsequent events. The complete process is summarized in Figure-1.

Our purpose is not direct sonification but non-rational exploration and narration. Sonic – and visual – production is not intended as a proxy for the actual data There is a new emergent narrative that references data both directly and obliquely. This narrative seeks a structural and syntactical relationship that is consistent and, in theory, comprehensible. Returning to Barthes, the narrative constructed in Ground-breaking is the result of a stochastic exploration of the soil data sets as cultural indices. The narration is both cyclical and open-ended; because periodic techniques are combined with probability functions, no cycle is repeated. The exploration is in part randomly driven, but, given that the data can be parameterised as a time-based (i.e. rhythmical) function, the narrative is also self-referential. The data sets have a functional role in the narrative; they are also a mode of description of the material objects that connotes actions. In this case, actions can only be deduced from the description, and may be human or environmental (such as interventions in land maintenance, firing bricks, flooding activity). So, a narrative emerges from the exploration of a data space, in which a sequence of actions can be deduced from functional descriptions of physical objects. 

CONCLUSION

The Ground-breaking installation was commissioned to raise awareness of the scientific aspects of how people have coped with extreme modifications, regardless of causation, of the environment of the African Sahel. The work has problematised notions of data representation, such that it offers a critique of data-sets rather than a simple audification. In doing so it has attempted to breach the barriers presented by different temporal and spatial scales: between landscape and the production of artefacts, between the scientific analysis of artefacts and their manufacture, between the perception of visual and sonified representations, and between micro-scale information and macro-scale evidence of extreme climatic change. Direct deduction of the human processes or environmental events is not explicitly sought such that the installation remains an unresolved generative work; in this form it promotes the audience towards a liminal space, an understanding of place and of rates of change.

The narrative developed explores a data space which contains as set of deduced actions from functional descriptions of physical objects; this has revealed the possibility that a yet more detailed data analysis and deeper data space exploration can produce further novel insights into the nature of the cultural imprints held by the soil. This also highlights the transferability of the meta-constructs of the narrative to other domains including other geographical environments with other cultural imprints. 

Bibliography

Adderley, W.P., Simpson, I.A. & Davidson, D.A. (2006) Historic landscape management: a validation of quantitative soil thin section analyses. Journal of Archaeological Science, 33, 320-334.

Adderley, W.P., Simpson, I.A., Kirscht, H., Adam, M., Spencer, J.Q., & Sanderson, D.C.W. (2004) Enhancing ethno-pedology: integrated approaches to Kanuri and Shuwa Arab definitions in the Kala-Balge region, North East Nigeria. Catena, 58, 41-64.

Adderley, W.P., Simpson, I.A. & Davidson, D.A. (2002) Colour description and quantification in mosaic images of soil thin sections. Geoderma, 108: 181-195. 

Barthes, R. (1977) Image, Music, Text. London: Fontana Press. 

Connah, G. (1981) Three Thousand Years in Africa: Man and His Environment in the Lake Chad Region of Nigeria. New York: Cambridge University Press, 268.

Hermann, T. & Ritter, H. (1999) Listen to your Data: Model-Based Sonification for Data Analysis. In G. E. Lasker (Ed.) Advances in intelligent computing and multimedia systems. Int. Inst. for Advanced Studies in System Research and Cybernetics, 8 Baden-Baden, 189—194.

Hunt, A., & Wanderley, M.M. (2002). Mapping performance parameters to synthesis engines. Organised Sound, 7:2, 103–114. 

Mandelbrot, B.B. (1977) The Fractal Geometry of Nature. San Francisco: W.H. Freeman, 365. 

Russ, J.C. (2006) The image Processing Handbook (Fifth Edition) CRC Press, Boca Raton, Florida.

Scaletti, C.(1994). Sound synthesis algorithms for auditory data representations. In G. Kramer (Ed.) Auditory Display: Sonification, Audification, and Auditory Interfaces. Addison-Wesley. 223–251. 

Young (2007) NN Music: Improvising with a ‘Living’ Computer. Proc. of the International Computer Music Conference. ICMA: San Francisco, 508-511.