McGill University Thèses et mémoires publiés en 1997

One of the key factors in ensuring safe slopes in open pit mines is the control of the groundwater flow within the slope. When analyzing the flow regime and its characteristics, traditional numerical methods designed for soil-like materials may not always apply. In the present thesis, the two-dimensional finite element code FlowD was developed to analyze steady-state seepage through fractured rock masses, under saturated conditions. The program provides the user with two modelling options: porous (soil) materials, or fractured rock masses. The double-porosity model was incorporated in the code, in order to better model flow through anisotropic, heterogeneous fractured rock …  Lire la suite

This study is inspired by social discourse theory and sociocriticism of literature. it aims to describe an organizational system that informs theatre practice in Quebec and to go beyond aesthetic form, critical interpretation and institutional structure to reveal Quebecois theatre in its most synthesized form. To comprehend the model's overall operation, three broad sectors of the theatre's sphere of activity were explored and juxtaposed: institution, reception and creation. For this purpose, a preliminary set of quantitative and discursive data was assembled from a study of the network of professional schools, associations, and festivals in the theatrical milieu. Following this, examination …  Lire la suite

The Microwave-Assisted Process (MAP$ sp{ rm TM}$) is an enhanced extraction technology patented by Environment Canada. MAP uses microwaves to rapidly transfer target compounds from one phase to another by selectively heating the phase containing the target compounds. This thesis presents the results of research performed to determine whether the MAP technique can be further developed into a large-scale soil treatment process that overcomes the limitations of conventional remediation technologies. The dielectric properties of several mixtures of acetone and hexane over a temperature range from 25$ sp circ$C to 50$ sp circ$C were measured. The dielectric constants of these mixtures …  Lire la suite

The development of artificial blood as an acceptable O$ sb2$-carrying substitute has been a desirable goal due to numerous problems associated with blood transfusions, a vital lifesaving procedure. Crosslinked hemoglobin forms a major class of potential blood substitutes in which hemoglobin is chemically modified. One of the requirements for generating a viable blood substitute is to control the formation of methemoglobin. Accordingly, a study was conducted to assess the ability of superoxide dismutase and catalase to control methemoglobin formation when both enzymes are crosslinked to ultrapure hemoglobin (Hb-SOD-CAT). In vitro experiments had shown that crosslinking superoxide dismutase and catalase to …  Lire la suite

Alginate beads produced by both external and internal gelation techniques were Studied so as to determine the optimal bead matrix structure within which DNA can be immobilized for in vim application. Alginates were characterized for guluronic/marmuronic acid (G/M) content and average molecular weight. Non-homogeneous calcium, alginate and DNA distributions were found within gels made by the external gelation method because of the external calcium source used. In contrast, the internal gelation method produces more homogeneous gels. The encapsulation yield of DNA was over 97 and 80% for beads formed using external and internal gelation methods, respectively. DNA molecular weight cut-off …  Lire la suite

In recent years, the rapid expansion of the consumer electronics market have resulted in a tremendous increase in the scope of applications for Digital Signal Processing (DSP) systems. Consequently, there is an increasing demand for ultimate quality DSP products which, in turn, necessitates structured design for testability (DFT) methodologies and in particular Built-In Self Test (BIST). The classical BIST schemes usually employ the specialized test pattern generation and test response compaction circuitry, which, in consequence, introduces a significant hardware overhead and performance degradation to a design under test. In this thesis, we propose an entirely new Arithmetic Built-In Self Test …  Lire la suite

This thesis is devoted to the optimal commitment of generation units in a power system, a problem known as a Unit Commitment (UC). This optimization is a difficult nonlinear mixed-integer task with various constraints whose exact solution can be found only through explicit enumeration. However, this technique requires impossibly long computational time and is impractical for most industrial applications. Various optimization techniques are proposed in the literature to solve the UC problem. In the present thesis, the Lagrangian Relaxation technique has been chosen for study. First, the Lagrangian Relaxation technique is applied to the static UC problem (SUC), that is, …  Lire la suite

Effects of growth environment (E) on carbon isotope discrimination (Delta), water-use efficiency (WUE), leaf movement (LM) and nutrition of bush bean were examined. Environments in greenhouse (GR), open air (E0), perforated (E1) and non-perforated (E2) plastic covers in combination with well-watered (W0), moderately-watered (W 1), and water-stressed (W2) plants were used. Soil water content (WC), E, and E x WC interaction significantly affected Delta, WUE, dry matter (DM) and water use. WUE, photosynthetic rate, and leaf nitrogen increased; while Delta, DM, and transpiration decreased with water stress in GR, and E0. WUE in E2 either decreased or remained almost constant …  Lire la suite

The case study examines the process of change undergone by the McGill Institute for Learning in Retirement (McGill ILR), a volunteered organization. ILRs have emerged across North America in the past 15 years and their success is attributed to the congenial participatory learning environment and the fact that members volunteer to administer the program activities in collaboration with a host university. Four years after it was founded, leaders sensed the need to evaluate McGill ILR's strengths and weaknesses. Under the aegis of McGill Centre for Continuing Education, a Planning Committee designed and implemented an organizational self-assessment to provide recommendations for …  Lire la suite

The bulk of research on teacher knowledge has taken place in elementary and secondary school settings. The goal of this study was to examine teacher knowledge in higher education by asking: (1) what types of knowledge are drawn upon in teaching in higher education and (2) Are there differences in the knowledge drawn upon by inexperienced (M = 5.77, SD = 2.8 years teaching), experienced (M = 18.79, SD = 7.36 years teaching), and professors who have won teaching awards (M = 19,50, SD = 7.60 years teaching)? Participants were selected at random from published lists of university faculty. Questionnaires …  Lire la suite

The purpose of this thesis is to explore the interplay of exegesis and ideology in the variety of Jewish medieval interpretation to Exodus 33:12-23. This thesis examines the intersection of ideology at three stages of the exegetical process. In the first stage, the commentator singles out "difficulties" in the biblical text. In the second stage, the commentator proposes formal solutions to these textual problems which provide a conceptual framework in which to introduce exegetical content. Finally, there are the actual comments themselves which provide the reservoir of exegetical content from which to glean the ideological tendencies of a particular commentator. …  Lire la suite

Kinematic design and performance evaluation of serial-type robotic manipulators is the main focus of this thesis with due attention being paid to redundant manipulators. The thesis provides a review of the existing contributions made to the subject, identifying those areas that can be advanced in depth or breadth and making theoretical contributions to some of these areas. The design, manufacturing and commissioning of a full-scale representative example of a redundant manipulator designed for kinematic isotropy is also discussed. Although various theoretical methods of analysis and characterization of the kinematic performance have been reported in the past two decades, the kinematic …  Lire la suite

Definitions and concepts of learning in the workplace have evolved considerably in the last two decades in response to significant changes impacting most workplace environments throughout the industrialized world. Comprehensive definitions of learning at work go beyond an emphasis on improving performance to consider the workplace as a social environment which can be structured to enhance or thwart adult learning and development. A wider and more socially relevant range of approaches to workplace learning are emerging. By focusing on learning as a process rather than a product, this study attempts to gain a deeper understanding of the daily informal learning …  Lire la suite

A PCR approach using degenerate primers specific for the highly conserved pore and S6 transmembrane domains of K+ channels was used to assess the diversity of K+ channels in the electric fish Apteronotus leptorhynchus. DNA sequence analysis has identified nineteen K+ channel genes, each of which can be classified into one of the four major families in a similar distribution to that in mammals. Also, an Apteronotus brain cDNA library was constructed and screened with mammalian K+ channel probes. The first K+ channel clone obtained displays remarkable amino acid sequence homology to rat Kv1.3 and Northern blot analysis and RNase …  Lire la suite

This dissertation presents two new systematic feedback approaches for set point feedback stabilization of drift free systems which employ Lie algebraic techniques. Due to some special features, drift free systems are known to be difficult to stabilize. For such systems, linearization, and state feedback linearization techniques, fail to be useful. In this dissertation two new feedback approaches the guiding functions approach and the trajectory interception approach are introduced. The importance of these approaches is due to their simplicity and the fact that they do not require any special transformation techniques. The guiding functions approach delivers piece-wise constant control sequences and …  Lire la suite

In this work, we explore the possibility of combining information from the VAD technique, with data from a wind profiler, to obtain the kinematic properties of a linear 2-D wind field. The idea is first tested on an artificial test-bed wind field, and the results show that the procedure is limited by the degree of non-linearity of the wind field over the wind profiler. To overcome this problem, some modifications are made to our procedure, which is then applied to real cases of stratiform precipitation. We find that the non-linearities are important enough such that the linear approximation is only …  Lire la suite

Canada's first Parliament Buildings, built in 1859--65 and destroyed by fire in 1916, were the nation's most prominent symbol of national identity and its most celebrated public space. Built into its fabric was an exclusively masculine definition of public persons, one which, at the end of the nineteenth century, women challenged in both subtle and overt ways. This research examines the design of the Parliament Buildings as a multi-faceted building type, a complex mix of domestic, office and legislative design where both public and "private" spaces intersected. It overlays official documentation of the buildings with a rich variety of sources---archival …  Lire la suite

Yates, Robin (Supervisor)  Lire la suite

Growth cones from rat dorsal root ganglia plated on laminin make transient adhesions through punctate integrin clusters called point contacts. We used immunocytochemistry to investigate if point contacts represent a specialized adhesive structure linking integrin clusters to the cytoskeleton. The cytoskeletal proteins vinculin, paxillin and talin colocalized with $ beta1$ integrin in a subpopulation of point contacts restricted to the lower membrane of the growth cone, in the central domain and at filopodial tips. The kinases p125$ sp{ rm FAK}$ and pp59fyn associated with the vinculin-positive clusters. The Rho GTPases were also present in growth cones, but only RhoB colocalized …  Lire la suite

On 1 October 1879 the German Imperial Court, the Reichsgericht, was formally opened in a ceremony in Leipzig. Decades of division among the German states, particularly in the years between the end of the Holy Roman Empire in 1806 and the creation of the German Reich in 1871, led to constant demands for national unification on political, economic, social and legal levels. Throughout those years proposals for Rechtseinheit, or legal unity, called for numerous substantive reforms as well as procedural or institutional reforms. Such proposals ultimately led to several important legal reforms, including the adoption of the Imperial Justice Laws …  Lire la suite

The organum vasculosum of the lamina terminalis (OVLT) is believed to be the central osmoreceptor involved in the regulation of extracellular fluid osmolality. While OVLT neurons have been reported to be excited by hypertonicity, it has remained unknown whether they can directly detect changes in fluid osmolality. Whole-cell patch-clamp recordings were therefore obtained from neurons acutely isolated from the OVLT. Increases and decreases in osmolality were found to cause respective depolarizations and hyperpolarizations, responses which seemed to be mediated by the volume-dependent modulation of a non-selective cationic conductance. Osmosensitive OVLT neurons were also found to contribute to the osmotic control …  Lire la suite

Recent criticism has cast the suburban playhouses of Early Modern London as marginalised institutions, in at least a topographic if not a symbolic sense. This thesis will contend that marginality is a relative term, and that for the inhabitants of the suburb, of Clerkenwell, the salient social function of the Red Bull theatre was not to serve the City as a site for licence, but to provide a neighbourhood space in which bonds of community could be formed. Arguing that theatres were built in particular locations not just to escape City prohibitions, but to draw on proximate audiences, I provide …  Lire la suite

This study investigates successful small Canadian firms that export. Four factors are considered from a theoretical perspective as variables that have affected the success of these firms. Regimes define the international and national environment. State support is studied as a strategic factor at the domestic level. Networks are considered as both strategic and organizational factors at the firm level. The study of internal factors considers organizational capability and strategy at the firm level. The empirical research was conducted through field studies and a questionnaire that was completed during an in-depth interview with the president, founder or principal officer of 21 …  Lire la suite

Mechanical weeders were tested on both mineral and organic soils in 1995 and in 1996, to measure their impact on soil physical properties. The weeders were tested in three crops, carrots in mineral and organic soil, beans in mineral soil, and lettuce in organic soil. Soil bulk density and water content were measured at regular intervals during the weeder trial period, and samples for soil structural analysis were collected in the mineral soil at the beginning and at the end of each season. No significant results were found in differences in mean weight diameters of dry and water-stable aggregates. Soil …  Lire la suite

Richard Serra's sculpture constitutes a political act through its analytical and operative strategies: analytical, when the work exposes the structures that frame our intersubjectivity, and operative, when the work acts as an example of resistance to the habitual acceptance of these structures. The significance of this oeuvre to architecture is that Serra's sculpture deliberately presents itself as something just shy of architecture, claiming its critical role to be that abandoned by--and proper to--architecture.  Lire la suite

This study investigated changes in self-esteem and perceived problem solving ability of academically at-risk students participating in a program called Science of Survival. The program combined adventure education and problem based learning approaches. One hundred and fifty-five male and female students, between the ages of 16 and 24 years completed the Self-Esteem Inventory and the Problem Solving Inventory at the beginning of the semester, after an adventure experience weekend, and at the end of the semester. A group of seventy-seven first year social science students, serving as a control group, also completed the inventories on the same time schedule. Self-esteem …  Lire la suite

The primary and secondary mafic silicates from the Amba Dongar carbonatitic-alkaline complex, Gujarat, India and the Strange Lake peralkaline granitic complex, Quebec-Labrador, Canada are the subject of this investigation of their origin, evolution and relationship to mineralization. Primary minerals are transformed by a variety of processes related to their crystallization history. The most important of these processes are: magma evolution, magma degassing and metasomatism. These processes are commonly associated with the evolution of peralkaline granitic and carbonatitic-alkaline complexes, and with the formation of associated mineral deposits (e.g., fluorite in the Amba Dongar complex; Zr-, REE- (rare-earth elements), Be-, Nb-and Y-rich …  Lire la suite

Two studies were conducted to examine the hypothesis that compliance may be a "keystone" behaviour for intervention for children with developmental delays. The relations among children's behaviours were examined during teaching sessions conducted either by children's mother or an unfamiliar examiner. Specifically, the relations between children's compliance with instructional requests and their attention, affect (positive and negative), and inappropriate behaviours (inappropriate object use, inappropriate vocalizations, inappropriate sitting, wandering, and self-directed behaviour) were examined. In both studies, highly compliant children showed less negative affect and were more attentive to the tasks than were less compliant children. Highly attentive children, in turn, …  Lire la suite

In this thesis we give a positive answer to the question "Is it true that the set of all definable elements of $ rm { bf R sp{f}} subset$ R, where R is the set of real numbers, is elementary substructure of R in HF-logics?" This result is proved under the set-theoretic hypothesis of Projective Determinacy (PD). We also study the structure of hereditary finite closure of a set; the notions of pattern and matching of patterns are discussed in sufficient detail.  Lire la suite

This thesis explores three fundamental issues in the phonology and morphology of Ethiopian Semitic languages: mobile morphology, reduplication and epenthesis. In each chapter I draw on comparative evidence from different Ethiopian Semitic languages, an approach which provides greater insight into how the languages vary with respect to these three issues, and how the issues themselves are best analyzed. The first issue is that of 'mobile morphology' a term I coin to describe the ability of a particular morphological category to be realized on various segments within a stem. The two major types in the South Ethio-Semitic languages are palatalization and …  Lire la suite

A low-temperature atomic force microscope has been designed and built. The instrument will operate at liquid helium temperatures, and will be used to investigate a number of phenomena observable only at low temperatures, including flux pinning mechanisms in superconductors, as well as domain structure dynamics in microfabricated ferromagnetic particles. This thesis provides a general review of force microscopy, including a summary of the forces to which the instrument is sensitive, as well as the most common modes of operation of the force microscope. An overview of our newly constructed low temperature microscope is then presented, examining each of the components …  Lire la suite

The purpose of the present study was to assess whether girls with LD were at a greater risk for self-reported depressive symptomatology compared to both boys with LD and girls without LD. Differences in the pattern of responses of girls with LD and boys with LD on the Children's Depression Inventory (CDI) were also evaluated. In order to identify a learning disability, the short-form of the Weschler Intelligence Scale for Children and the Wide Range Achievement Test were administered to 204 subjects. Results revealed that girls with LD demonstrated an increased risk for depressive symptomatology as compared to girls without …  Lire la suite

The purpose was to examine the effect of shaft stiffness on puck velocity and response characteristics of the stick during performance of a slap shot. Six elite male ice hockey players performed 6 slap shots with 4 sticks of different shaft stiffness designated as medium (13 N/m), stiff (16N/m), extra (17 N/m) and pro stiff (19 N/m). These four levels represent the range in stiffness of sticks available to hockey players. The mechanics of the slap shot were evaluated by recording ground reaction forces and kinematics from high speed filming and a radar gun. Data were analyzed with a 3-way …  Lire la suite

The highly varying course of MS has made it difficult to establish accurate prognoses about its natural history. The reliability of neurologic impairment grades obtained by clinical examinations of patients is becoming recognized as important. Current statistical methods in natural history studies of MS are essentially classical survival and linear models, applied to clinical data and with mortality, impairment, and secondary progression of MS, as outcomes. However, more sophisticated modelling attempts, in particular ones that account for the fluctuating course of MS, are rare. Stochastic and time series models are two such recent methods that have been proposed. As more …  Lire la suite

The behavior of transgenic mice with impaired type II glucocorticoid receptor function was examined in a nonspatial learning task, the forced swim test, as well as in a spatial memory task, the water maze. Antidepressants have been shown to alter behavioral performance in these paradigms, as well as HPA axis activity in these animals. Transgenic and B6C 3F1 mice were therefore chronically or acutely injected with desipramine (10 mg/kg) or fluoxetine (10 mg/kg) for the forced swim test. Both drugs were chronically administered for the water maze. Transgenic mice exhibited impairments in the forced swim test that could be secondary …  Lire la suite

In this thesis we investigate three approaches to generating new solutions to low energy string theory. The first one consists in gauging WZW models. We construct a gauged extension of a model first introduced by Witten and Nappi. Then we look at Garfinkle's wave generating technique and apply it on a known five-dimensional black string to generate a new family of solutions. We investigate their properties with a special emphasis on singularities. Finally, in the last part, we study O(d, d + p) transformations and duality and we explore the effect of gauge transformations on those transformations. With the latter, …  Lire la suite

The somatosensory representations of hands and feet were determined using spatio-temporal source analysis of median and posterior tibial nerve somatosensory evoked potentials (SEPs). In 10 control subjects, modeled generators mapped on MRI correlated well with the primary somatosensory cortex identified with strict radiological criteria. For median nerve stimulation, the main generator was located 3.5 mm from the central sulcus on average (after correction for eccentricity) and was perpendicular to it. For posterior tibial nerve stimulation, the main generator was slightly anterior to the central sulcus (average distance 6.6 mm) and pointed predominantly posteriorly and towards the longitudinal fissure. In 3 …  Lire la suite

This thesis is a monograph on the facade of the church of Santa Maria Novella in Florence, Italy. The present appearance of the facade is the result of three building campaigns effected over the period of two centuries (c1300--c1500), and two restorative campaigns conducted in the twentieth century. Each of the three major campaigns is considered in isolation, with attention to reconstructions, formal and comparative analyses, and extensive contextualization and discussion of patronage networks. The twentieth-century interventions are cursorily presented in an epilogue. Major themes developed and continued through the five chapters of the dissertation are: architecture and its projected …  Lire la suite

Typically, when a robotic manipulator undergoes rapid acceleration, there is a commensurate loss in end-effector positional accuracy. To achieve high accuracy of the working end, massive links are usually required. Conversely, to achieve high accelerations, thin and flimsy links have to be employed, only to be plagued by large end-effector vibrations and long settling times. However, this traditional tradeoff can be circumvented through the application of high-performance materials such as graphite/epoxy which exhibits high stiffness-to-weight and strength-to-weight ratios as well as good damping properties. This thesis describes the process of designing and fabricating the three principal mechanisms of an anthropomorphic …  Lire la suite

We consider the problem of rendezvous between two robots exploring an unknown environment. That is, how can two autonomous exploring agents that cannot communicate with one another over long distances meet if they start exploring at different locations in an unknown environment. The intended application is collaborative map exploration. Ours is the first work to formalize the characteristics of the rendezvous problem, and we approach it by proposing several alternative algorithms that the robots could use in attempting to rendezvous quickly while continuing to explore. The algorithms are based on the assumption that potential rendezvous locations, called landmarks, can be …  Lire la suite

The first three studies in this thesis address the mechanism for the aberrant fall in serum 1,25-dihydroxyvitamin D$ sb3$ (1,25-(OH)$ sb2$D$ sb3 rbrack$ and increase in renal 1,25-(OH)$ sb2$D$ sb3$-24-hydroxylase(24-hydroxylase) activity in X-linked hypophosphatemic mice (Hyp). The 24-hydroxylase is the first enzyme in the C-24 oxidation pathway that degrades the vitamin D hormone to its final inactivation product, calcitroic acid. We demonstrated that: (i) the aberrant increase in 24-hydroxylase activity in Pi-deprived Hyp mice is specific to the kidney and is the result of an increase in enzyme Vmax, immunoreactive protein and mRNA abundance; (ii) the increase in 24-hydroxylase mRNA …  Lire la suite

Fictional characters who mistake reality for fiction can be considered as parodies, beings invented by the author to denounce the illusions of which they are victims. But this viewpoint is not valid if the novels in which those "mistaken readers" exist suggest, to the contrary, that reality is problematic; it is therefore impossible to judge the characters without "afterthoughts", since these characters, in a way, are pointing to the fact that the reality they live in is "unreal". Such is the case with Madame Bovary and Don Quijote. These two novels, as a result of different "techniques", essentially tell their …  Lire la suite

This research investigates the use of a deformable model representation in the context of an active exploration process. The exploration process is used to acquire data, fuse measurements from different viewpoints, and construct shape models. Until now, approximate shape models, e.g. superellipsoids, have been used to represent objects in an active exploration strategy. Although these models provide an adequate characterization of 3D shape for many tasks, a more detailed representation is needed when it comes to tasks that require discrimination of similar objects. In this thesis, we explore the use of a class of deformable models, developed by Pentland and …  Lire la suite

During the 1910s, there was an increasing concerted effort on the part of Canadian artists to create art and literature which would affirm Canada's sense of nationhood and modernity. Although in agreement that Canada desperately required its own culture, the Canadian artistic community was divided on what Canadian culture ought to be. For the majority of Canadian painters, writers, critics and readers, the future of the Canadian arts, especially poetry and painting, lay in Canada's past. These cultural conservatives championed art which mirrored its European and Canadian predecessors. Their domination of the arts left little room for the progressive minority, …  Lire la suite

Peters, Terry (Supervisor)  Lire la suite

This thesis explores the role of an adhesion protein, CD44, in the biology of colon cancer. CD44 glycoprotein is a main extracellular receptor for hyaluronic acid. A single CD44 gene composed of 20 exons encodes a variety of isoforms due to alternative splicing of 10 middle exons. Overexpression of CD44 and appearance of abnormal isoforms containing products of variant exons have been implicated in the origin and progression of cancer, including human colon carcinoma. Of two main parts comprising the dissertation, the first one ("CD44 and the adhesion of neoplastic cells" by Z. Rudzki and S. Jothy) reviews the current …  Lire la suite

During 1975 the Architect Christopher Alexander designed and built an experimental project for low income people in the city of Mexicali, Mexico. The aim of the project was to create a beautiful place, not just of architectural beauty but in its essential spirit, in its quality of life. A number of patterns, taken from the book A Pattern Language, were used to design the environment. The residents played an important role in the design of their place: this, according to the author, would guarantee that the place would directly respond to their physical and spiritual needs. Today, 20 years later, …  Lire la suite

Ors8 is a mammalian autonomously replicating DNA sequence, previously isolated by extrusion of nascent CV-1 (monkey kidney cells) DNA from replication bubbles active at the onset of S phase. A panel of deletion mutants of ors8 have identified a fragment of 186 bp that is essential for the in vitro and in vivo replication of ors8 containing plasmid. This fragment, when subcloned into pBR322 and similarly tested, was capable of autonomous replication in vivo and in vitro (Todd et al., 1995). The objective of the research in this thesis is the purification and characterization of a mammalian factor(s) that specifically …  Lire la suite

This thesis is a comparative study of the educational reforms initiated by the Aligarh and Muhammadiyah movements in India and Indonesia respectively. It covers three main points: Ahmad Khan's and Ahmad Dahlan's educational philosophy; the educational system of the Muhammadan Anglo-Oriental College (MAOC) and Muhammadiyah schools; and the impact of the educational reforms of the two movements to Muslim education in general in the two countries. As will be explained in this thesis, Ahmad Khan and Ahmad Dahlan were deeply concerned with economic and social problems faced by the Muslims due to colonial policies. Both scholars came to the conviction …  Lire la suite

The objective of this work is to design a system for the visualization of geographical terrain in three dimensions. The input of such a system is the contour map of the region to be visualized. Several approaches to solve this problem can be found in the literature. Our approach is based on surface reconstruction or interpolation. We achieve the reconstruction of the terrain surface by pairwise triangulation of map contours in adjacent height levels. The large data size in this application dictated the use of an optimal triangulation algorithm. The algorithm we employed (by G. Toussaint) runs in $O(n(1+t sb0)$ …  Lire la suite