• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 9933
  • 2714
  • 979
  • 339
  • 339
  • 327
  • 311
  • 239
  • 130
  • 98
  • 84
  • 81
  • 80
  • 59
  • 57
  • Tagged with
  • 14482
  • 2402
  • 1693
  • 1615
  • 1401
  • 1352
  • 1242
  • 869
  • 754
  • 717
  • 712
  • 654
  • 648
  • 647
  • 597
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

The traditional architecture of the Igbo of Nigeria

Nsude, Godwin Chikwendu January 1987 (has links)
Modern architecture in Nigeria presents a bizarre picture of indiscriminate transplantation of foreign buildings, and a complete abandonment of traditional architecture. Apparently, the transplanted architecture does not respond to the physical and cultural needs of Nigerians, and, at all events, the peoples' attitude to it portrays ignorance, confusion and resignation. This thesis argues that rather than this wholesale transplantation, Nigeria's traditional architecture should be studied to rediscover those principles that are vital for the development of a satisfactory modern architecture. The thesis is confined to Igboland, and traditional Igbo architecture is studied in the context of the physical and cultural environments under which it evolved and developed. The study reveals that traditional Igbo architecture is a product of physical and cultural factors, some of which are peculiar to Igboland and society. These factors create architectural problems and also provide some means of solving them. The physical environment, for instance, causes the problem of rain, heat and humidity, but provides mud, timber, bamboo and palms for house building. Similarly the Igbo world-view imposes a philosophy which constrains ordering in the physical world to mirror a conceptual ideal one. Again, this provides a theoretical principle by which the Igbo order architectural elements in the physical setting. The traditional architecture, therefore, directly relates to their environment and long-established customs and way of life. Colonization and the ensuing transplantation of foreign architecture have, however, undermined it and created problems. These problems are highlighted here, but with the recognition that erasure of the transplanted buildings is no solution. It is further established that traditional architecture is not anachronistic, but possesses valid ordering and design principles, technical solutions and upgradable materials. A compromise is therefore sought whereby these can be exploited to cross-fertilise current practice to achieve a satisfactory modern architecture in Igboland and Nigeria.
62

Daylight and glazing specification : the impact on non-visual processes

Paradise, Caroline January 2015 (has links)
The aim of this thesis was to establish whether the choice of glazing system could be impacting on the well-being of building occupants beyond the response of the visual system, based on the daylight they receive within a building interior. Daylight utilization is inherent to the success of a building, and a number of parameters within the design of interior spaces have an impact on daylight distribution such as size of window and depth of room, as well as colour and reflectivity of surfaces. This thesis therefore also aimed to establish the relative importance of the choice of glazing in respect to these other parameters. Through an extensive literature review of biomedical, neuroscience and chrono-biological research, a set of lighting parameters for the stimulation of non-visual responses were defined based on two processes; circadian entrainment (or phase-resetting) and subjective alertness. Whilst this biomedical research is inconclusive at the time of completing this thesis, these parameters provided a basis from which to assess the potential effects of different lighting environments with respect to the well-being of building occupants. Physical measurements and a digital model of a Case Study room were used to establish the impact of a range of glazing systems on the light that reaches a person’s eye. These studies showed that it is insufficient to rely on traditional horizontal illuminance measurements alone to ascertain whether a given space will provide enough light to support the non-visual system. It also showed that the effect of the glazing is strongly interconnected with other design parameters of the room, such as the colour of the surfaces. Overall though, the glazing specification had the most significant impact on the light that reaches a person’s eye within the Case Study room. In conclusion this thesis shows that, based on current understanding of non-visual lighting requirements, the choice of glazing does have an important impact on the non-visual processes connected to the eye. Of the variables within the control of the designer the specification of glazing has been shown to have the most significant impact. Further design guidance is needed to avoid the potential health implications of poor glazing choice.
63

Investigating the processes of socialisation in architectural education : through experiences in East Africa

Olweny, Mark Raphael January 2015 (has links)
This thesis investigates socialisation in architectural education in East Africa. It was hypothesised that socialisation formed an integral part of professional education,through which students acquired undocumented, but nonetheless important aspects of the profession, building both values, and a cultural ethos in the process. Socialisation in the context of architectural education, thus takes on added significance, given the longevity of the educational process, as well as the close association between faculty and students. The outcomes of the educational process thus evoked questions of the transformative nature of the process, and how this was effected. Undertaken as an ethnographic study, the research investigated elements of socialisation within five established architecture schools across East Africa. Framed in the context of a learnscape of architectural education, the study examined influences on architectural education in three key areas: Pre-socialisation; Institutional socialisation; and, educational socialisation. A mixed method approach was used, addressing the contextual diversity presented by the setting of East Africa. The mixed method approach made use of document analysis, a questionnaire study, focus group discussions, and participant observations, as data gathering instruments. The variety of methods, along with the multitude of study sites, ensured data triangulation as a key element in validation of the findings. The study revealed socialisation as being an important and integral component of architectural education, existing at all stages of the educational process. Prior to entry into architectural education, pre-socialisation served to inform student ideas and values related to the profession, often based on uninformed perspectives. Institutional influence, presented a traditional educational approach, creating culture shock for incoming students through a misalignment of values between students and architectural education. The contrasting expectations of student and faculty,and the attendant influence on socialisation, were overtly evident in the educational realm. This was highlighted by approaches to contemporary issues in architectural education, and the nature of educational activities within the schools. Through this research, socialisation was found to be an integral part of architectural education. Far from being a mere puzzling phenomenon, ignored and taken for granted,socialisation forms a fundamental part of architectural education, which forms a critical part of the education of architects.
64

Prediction of sound and vibration response using transient statistical energy analysis

Robinson, Matthew January 2012 (has links)
Transient sounds generated from structure-borne and airborne excitation are very common in buildings and cause the majority of disturbances in dwellings. The maximum sound pressure level corresponds well with annoyance and disturbance and current guidelines use this descriptor to describe the threshold for sleep disturbance. Hence this thesis addresses a need for methods to quantify transient sound sources and prediction models that can determine maximum sound pressure levels due to these sound sources. Statistical Energy Analysis (SEA) provides a framework that describes sound radiation and structure-borne sound transmission in buildings. SEA is used in this thesis as a basis on which to develop Transient Statistical Energy Analysis (TSEA) for building acoustics. The TSEA power balance describes energy exchange between subsystems in the time domain and is controlled by the time interval. Limits for the time interval are proposed based upon energy decay and path statistics of the source subsystem. New methods are proposed for measuring and quantifying the transient power input from airborne and structure-borne excitation. Detailed analysis is also used to quantify the signal processing errors, due the time-weighted level detector and filters, associated with the measurement of maximum levels. The use of steady-state SEA coupling loss factors in TSEA for sound radiation and structure-borne sound transmission is validated through good agreement in comparisons of measurements and predictions of maximum sound and vibration levels. This validation is extended to complex transient sources that have been incorporated into TSEA, such as the ISO rubber ball, transients overlaying stationary noise and airborne transients. Case studies of heavyweight buildings show that accurate predictions of maximum sound pressure and vibration levels are given if Ns ≥ 1 and Mav ≥ 0.5. TSEA has also been validated for the prediction of structural decay curves, numerical experiments have been carried out to quantify the error in the estimation of the total loss factor and to develop an improvement to the evaluation of decay curves.
65

Evaluating the functional performance of small-scale public demountable buildings

Xi, Junjie January 2013 (has links)
This thesis investigates the design, operation and use of contemporary demountable buildings, and explores how functional performance can be assessed in small-scale examples for public use alongside with their relationship to other design elements. The research focuses on three case studies that do not require a high-technology building environment or complex construction skills. Demountable buildings are defined as those that are transported in a number of parts for assembly on site. Contemporary demountable buildings respond to ecological issues, social impacts, technological innovation and economic demands. They can be used to measure a society’s development in environmental sustainability, innovation and economic growth through various forms. Small-scale demountable buildings fulfil many temporary habitation needs in diverse roles, such as non-emergency transitional housing, ephemeral exhibition buildings and seasonal entertainment facilities. The purpose of examining functional performance is to assess if, and how, the requirements of the design have been achieved. This enables project operators to address functional performance from a public perspective by reflecting on the scope and ambition of their projects. This thesis draws on existing literature to investigate previous and on-going research relating to demountable buildings, including classification, the construction process and project management. It also examines selected existing evaluation methods that cover principles, modelling and computer-based solutions from a wider research area, including Guidelines Developed by City Council and Culture Sectors; Assessment Methods in Humanitarian Response and Methods in Environmental Assessment. The research was conducted by combining both quantitative and qualitative research methods, including field research, case studies, interviews, questionnaires and group discussions. Fragmented narratives were transformed into structured evidence, identifying models of best performance in demountable buildings and developing a new method – the Evaluation Conceptual Model – for the effective evaluation and evidencing of the value of demountable buildings in the 21st century. Recommendations for adapting a suitable model to evaluate other design elements in demountable buildings and other types of moveable buildings in further research are suggested and the findings have been used to lay the foundations for a practical evaluation tool for the future.
66

Parkour and the city : the role of human mobility in place-making

Otchie, Michael January 2013 (has links)
The intention of this thesis is to frame the emerging discipline of parkour into the context of architectural research. The thesis takes into consideration a range of research methods including interviews, literature and film reviews, and filmmaking exercises. The subject of the documentary films produced for this study, are a series of tours of the city of Liverpool that are carried out by practitioners of parkour, so-called traceurs, and university architecture students. By using these tours of Liverpool as case studies, the research project provides a novel approach to understanding the multi-sensory qualities of urban spaces, and builds upon practices found within the emerging field of sensory-ethnography. These tours are used as a means to gather qualitative data that extends beyond verbal responses, as physical interactions between individuals and their surroundings are documented and analysed. The use of filmmaking techniques within this piece of research allows for it to build upon pre-existing practices found within the culture associated with parkour. By examining video filmmaking as a tool for documenting the relationship between traceurs and city spaces, this research study makes reference to the growth of the parkour movement via Internet based social networks and the proliferation of digital videos. The thesis concludes with a novel approach for understanding traceurs as an architectural figure, akin to the concept of the flâneur, which has significance for the interrogating multiple layers of meaning within contemporary urban space. The study also provides support for critically examining the development of subject knowledge and epistemological knowledge in relation to architecture and the body.
67

Vibrotactile perception of musical pitch

Mate-Cid, Saul January 2013 (has links)
Previous vibrotactile research has provided little or no definitive results on the discrimination and identification of important pitch aspects for musical performance such as relative and absolute pitch. In this thesis, psychophysical experiments using participants with and without hearing impairments have been carried out to determine vibrotactile detection thresholds on the fingertip and foot, as well as assess the perception of relative and absolute vibrotactile musical pitch. These experiments have investigated the possibilities and limitations of the vibrotactile mode for musical performance. Over the range of notes between C1 (32.7Hz) and C6 (1046.5Hz), no significant difference was found between the mean vibrotactile detection thresholds in terms of displacement for the fingertip of participants with normal hearing and with severe/profound hearing impairments. These thresholds have been used to identify an optimum dynamic range in terms of frequency-weighted acceleration to safely present vibrotactile music. Assuming a practical level of stimulation ≈10dB above the mean threshold, the dynamic range was found to vary between 12 and 27dB over the three-octave range from C2 to C5. Results on the fingertip indicated that temporal cues such as the transient and continuous parts of notes are important when considering the perception of vibrotactile pitch at suprathreshold levels. No significant difference was found between participants with normal hearing and with severe/profound hearing impairments in the discrimination of vibrotactile relative pitch from C3 to C5 using the fingertip without training. For participants with normal hearing, the mean percentage of correct responses in the post-training test was greater than 70% for intervals between four and twelve semitones using the fingertip and three to twelve semitones using the forefoot. Training improved the correct responses for larger intervals on fingertips and smaller intervals on forefeet. However, relative pitch discrimination for a single semitone was difficult, particularly with the fingertip. After training, participants with normal hearing significantly improved in the discrimination of relative pitch with the fingertip and forefoot. However, identifying relative and absolute pitch was considerably more demanding and the training sessions that were used had no significant effect.
68

Digital re-analysis of lost or unbuilt architecture

Webb, Nicholas January 2012 (has links)
The research presented here utilises contemporary digital techniques enabling a consistent analytical technique to systematically study significant works of unbuilt, damaged and destroyed architecture. The analytical technique provides a methodology that can be utilised for future research employing digital tools in the context of investigating historic works of architecture. Digital representation tools are therefore used to re-analyse and re-interpret unbuilt, damaged and destroyed works of architecture. This augments research already undertaken by architectural historians, who provide traditional critique and analysis, by testing such studies further using a range of contemporary digital techniques. The research is significant as it demonstrates how contemporary representation techniques can advance knowledge and understanding of significant architectural designs that once existed, or could have once existed. Consequently, this enhanced understanding can then be used to add to knowledge already attained about a particular architect and buildings they designed. Three case studies by important twentieth century architects were used to demonstrate and advance the methodological process provided. These were an unbuilt student project by Sir James Stirling, a pair of unbuilt museum projects by Auguste Perret, and a partially built cathedral design by Sir Edwin Lutyens. Each case offered its own benefits in researching the analytical technique. The Stirling case study enabled the techniques and principles of the methodological process to be established and demonstrated that it could provide enhanced understanding of an architect’s work. The Perret case study was important in finding unexpected results as part of the digital representation construction process, which enabled the methodology to be revised to take into account the significance of serendipity in the research. The Lutyens case study was particularly successful in developing lines of enquiry through looking at primary and secondary source data available for a design, which could then be used to re-analyse and enhance understanding of the design using digitally augmented techniques. The findings offer enhanced understanding of using digital tools as a technique to study unbuilt, damaged and destroyed works of architecture. In the first instance they demonstrate the significance of the process of constructing digital representations of such architectural artefacts. During this process inferences have to be made as representational source data such as architectural drawings are almost always incomplete, therefore parallel study into the architect, their architecture and the contemporary context they worked within has to be investigated in order to fill in gaps in an informed way. It is during this investigative process that enhanced critical understanding of an architect and their architecture is achieved. The findings also illustrate how contemporary digital tools can be used to augment and enhance knowledge of unbuilt, damaged or destroyed works of architecture by following particular lines of enquiry generated through the study of primary and secondary source data. The key here is the advanced knowledge that digital techniques bring when compared against critique of a work of architecture that was established in a pre-digital context.
69

Indirect methods of obtaining activity and mobility of structure-borne sound sources

Höller, Christoph January 2013 (has links)
The work reported in this thesis focuses on the development of indirect methods for the experimental determination of important source parameters for structure-borne sound source characterization. In the first part of the thesis, matrix inversion methods for the determination of blocked forces are investigated. A simplified measurement procedure is proposed which offers a solution to the two major challenges to these methods, namely the acquisition of the FRF matrix and the problems associated with matrix inversion. The proposed procedure involves a free, low-mobility receiver plate which is modelled numerically. Calculated FRFs are used together with measured velocity responses to inversely determine the blocked forces. It is found that while the method has great potential in principle, in practice the accurate modelling of the receiver plate is of critical importance. In the second part of the thesis, three formulations are considered for the indirect determination of source mobility. Instead of performing measurements on the source in the free state, the source mobility is obtained from measurements made in-situ. This approach is beneficial if the source is difficult to suspend, or if it contains non-linear structural elements. The three formulations are validated numerically and experimentally. It is found that the methods can quantify source mobilities of single-contact and multi-contact sources from in-situ measurements. However, typical measurement errors, such as background noise or inaccuracies in sensor positioning, can significantly reduce the accuracy and reliability of the methods. In the final part of the thesis, the reception plate method for the determination of the power injected by a high-mobility source into a low-mobility receiver is reviewed, and a source substitution method proposed as a development. The substitution method circumvents problems that may arise when the reception plate method is applied to coupled walls and floors. A special focus of investigation is on the calibration of the receiver structure. It is found that the calibration can be performed with shaker or hammer, and that an average calibration factor may be used. The source substitution method thus offers a potential alternative to the reception plate method, for application with coupled plates.
70

Prediction of bending wave transmission across coupled plates affected by spatial filtering and non-diffuse vibration fields

Wilson, David January 2014 (has links)
This thesis concerns models based on Statistical Energy Analysis (SEA) to predict bending wave vibration in heavyweight buildings from structure-borne sound sources such as machinery. These sources tend to inject most power in the low- and mid-frequency ranges where the walls and floors have low mode counts and low modal overlap for which calculated Coupling Loss Factors (CLFs) from semi-infinite plate theory can be in error. For machinery it is necessary to predict vibration on walls/floors that are remote from the source room. In this situation, propagation across successive structural junctions causes spatial filtering of the wave field and the assumption of a diffuse field in each plate subsystem breaks down. The predictive approach described in the European Standard EN12354 uses SEA path analysis which assumes that transmission is dominated by first-order paths. However the feasibility of extending the concept of path analysis to walls and floors of rooms that are distant from the source room(i.e. not adjacent) is unknown. These issues are addressed in the thesis. The feasibility of SEA path analysis was assessed by quantifying the total contribution to receiver subsystem energy from paths containing specified numbers of CLFs. For receiving subsystems which are attached directly to the source subsystem, the EN12354 approach was found to underestimate the energy levels. For rooms remote from the source room, path analysis was found to significantly underestimate the vibration of the walls/floors which form the receiver room. Alternative approaches to improve predictions in large heavyweight buildings were assessed through comparison with Monte-Carlo Finite Element Method (MCFEM) models which were validated on a small heavyweight building. Matrix SEA was used with CLFs calculated for L-, T- and X-junctions using analytical models for rectangular plates to try and incorporate modal features. For isolated junctions, there was good agreement with MCFEM but in large buildings. However, it was unable to predict the peaks and troughs in the vibration response to one-third octave band accuracy although it can estimate the envelope response for plates that are directly connected to the source plate. In general, matrix SEA using finite plate theory CLFs does not improve the prediction in one-third octave bands when the statistical mode count is less than unity. Ray tracing was therefore investigated which showed that the angular distribution of power incident on the plate edges differed significantly from a diffuse field. Computationally efficient ray tracing was then developed for inclusion in Advanced SEA (ASEA) models to account for indirect coupling between plate subsystems. ASEA gave significant improvements over matrix SEA when there were large numbers of structural junctions between the source and receiving plates.

Page generated in 0.0883 seconds