• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5136
  • 3499
  • 2209
  • 1150
  • 1110
  • 390
  • 123
  • 110
  • 109
  • 105
  • 88
  • 81
  • 76
  • 76
  • 60
  • Tagged with
  • 16930
  • 2613
  • 2015
  • 1826
  • 1775
  • 1484
  • 1449
  • 1443
  • 1389
  • 1280
  • 1208
  • 1173
  • 1062
  • 911
  • 847
  • 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.
361

Improving Wayfinding in old and complex hospital environments

Rooke, C. N. January 2012 (has links)
Many hospitals have developed over a number of years in a piecemeal fashion. This has resulted in complex environments made up of long and confusing corridor systems with bends, turns, and confusing signs. Such settings challenge and frustrate those who visit them. The importance of wayfinding to building use, costs and safety and the growth in terms of theories, principles, guidelines, and methodologies over the years does not appear to have made an impact on wayfinding performance in complex hospitals. Thus, there remains a need to find more effective wayfinding solutions to the problems that continue to occur in complex hospitals. This research aims at improving methods for developing wayfinding systems and strategies in old and complex hospital environments. The study adopts a design science research approach informed by uniquely adequate observations of how wayfinders make sense of wayfinding information embedded in the complex built environments they have to navigate. The approach includes an extensive review of literature on wayfinding supported by that of the fields of knowledge management, design (architectural and industrial), and production and operations management. The research brings together the disciplines of design and knowledge management to sensitise designers to the varied needs and knowledge levels of wayfinders when designing wayfinding systems. Drawing on findings from both the review of literature and extensive ethnographic fieldwork the research has produced prescriptive and evaluative wayfinding frameworks to aid the design of effective and efficient wayfinding systems and strategies. The outcome of successfully applying the design science research approach to researching the problems of wayfinding and mapping the approach research process with the unique adequacy approach is the Wayfinding Conceptual framework. It represents a methodological contribution, aimed at helping to mitigate the problem of relevance often associated with academic management research.
362

City centres : understanding the travel behaviour of residents and the implications for sustainable travel

Asad, F. H. A. January 2013 (has links)
The study aims to understand the city centre living characteristics from a sustainable travel behaviour perspective. Three datasets have been utilised; the UK Trip Rate and Information Computer System (TRICS), the Scottish Household Survey and an original household travel survey which has been conducted in Manchester city centre. An array of univariate and multivariate statistical techniques have been utilised to conduct the required travel analysis and modelling. Using Trics 2012a, exploratory analysis has shown a significant variation in the urban form characteristics between residential neighbourhoods located in central locations and those located in other areas. Households in the central locations generally travel less than others; in particular, town centre households walk more and drive less than others in out-of centre areas. In contrast, the inferential analysis showed evidence of a mediation effect whereby neighbourhood features such as the ratio of flats, parking density and transit provisions explain some of the differences in trip frequency. The mediation analysis also revealed that built environment features only partially account for these differences. The Scottish Household Survey and the Manchester city centre survey datasets have been utilised in order to investigate the potential impacts of several socio-spatial and attitudinal attributes on the city centre residents’ personal mobility. Whereas the review process disclosed the notable increase in the residents of the UK city centre and a revival of its housing sector over the past decade, the descriptive analysis revealed some distinct characteristics of those residents such as they are typically young adults, modern and well-qualified and living in single person households or as couples. Walking is their common mode for commuting, shopping and leisure. In Manchester city centre, 42% of the residents’ journeys were found to be within the city centre catchment area. In contrast, the travel behaviour models indicated the potential impacts of socio-spatial attributes such as car ownership, income and parking on mobility measures such as car ownership, mode choice and vehicular mileage. Finally, some attitudinal factors were found to be influential even after controlling for the socio-spatial effects.
363

Organisational readiness to implement building information modelling : a framework for design consultants in Malysia

Haron, A. T. January 2013 (has links)
Building Information Modelling (BIM) is defined as an approach to building design and construction through modelling technology, associated sets of processes and people to produce, communicate and analyse building information models. The implementation of BIM is expected to improve the delivery of design and construction through 3D visualisation, integrated and automated drawing production, intelligent documentation and information retrieval, consistent data and information, automated conflict detection and automated material take off. Although the potential benefits of BIM are well documented, the implementation process requires proper strategic planning and a thoughtful review of many aspects to realise those benefits. One part of the strategic planning is the readiness assessment where it measures the current position of the organisation as compared to the targeted implementation requirements of the BIM system by using several categories and readiness criteria. Set against the background of the Malaysian construction industry, in the infancy stage of BIM implementation, however has raised the question about the categories and the readiness criteria that should be used to conduct the assessment. The lack of documented BIM implementation in a form of publicly available reports, best practice and guidelines has also escalated the situation. The aim of this research was therefore set to support improvements in the design consultant practice by developing an organisational readiness framework for BIM implementation. The research explored and identified the readiness criteria as the main components of the framework. The research engaged a multiple-case-studies approach and four design consultant companies were selected for the primary data collection. Data from each company was analysed by using content analysis technique before it was cross analysed to determine the pattern of answer. After that, the findings were discussed and theoretically validated to produce a conceptual framework. The conceptual framework was later validated through a focus group workshop to produce the final framework. As the research’s main outcome, the readiness framework consists of four elements. The first readiness element is Process which has three categories residing within it, which are, Process Change Strategy, BIM Implementation Management, and Policy. The second readiness element is Management which includes the categories of Business Strategy, Management Competency, and Leadership. The third element is Technology which also has three categories residing within it, which are Hardware, Technical Support, and Software and the fourth element is People, which has four categories and they are, Roles and Responsibilities, Skill and Attitude, Training and Education and Work Environment. Meanwhile, the 38 readiness criteria that were identified and validated, resided accordingly within each readiness category. The readiness framework as the main outcome of the research can be used to assist the design consultant to identify the readiness gap of the company. The importance lies on informing the area of concern so the effort for BIM implementation can be prioritised. In addition, the individual case study report which had information rich data could help the industry to understand the BIM implementation issue within the context of Malaysia. The outcome of this research showed that the main problems that are preventing consultants from embracing BIM were rarely technical. They were related more to the management and people issues which underpin the capability of the company to successfully implement BIM.
364

An exploration of the employee's perception of walking : enhancing the walking experience in Kuala Lumpur

Adam, M. January 2014 (has links)
Urban planners in the Transportation Department of Kuala Lumpur, over a period of time, noticed a progressive increase in the influx of privately-owned vehicles into the city and decrease in the modal share of public transport. Over-dependence on cars has encouraged a sedentary lifestyle, an obesity epidemic, social exclusion and increased carbon foot print. This research investigates the factors that have led to the increasing dependency on private vehicles by employees who work in employment centres in Kuala Lumpur city. Deficiencies in urban planning have created a spatial separation between people and workplaces, meaning that the existing built environment and land uses are inadequately coordinated with various modes of transportation which could facilitate the movement of people in the city. This results in long hours of commuting between employment centres and residential areas, and causes severe traffic congestion into the city centre daily. Understanding this real life phenomenon in a holistic manner is vital in order to find or create alternatives to car dependency and traffic congestion, as it will show how people construct the meaning of commuting in their built environment, and how commuting can be beneficial to them. In order to establish these arguments, the research takes a qualitative research approach, collecting data from multiple sources of evidence such as interviews and participant observation. A multiple embedded case study approach was adopted, using two contrasting areas in the city of Kuala Lumpur as samples; both the user and the pedestrian environment were used as units of analysis to measure the research questions. This allowed for the use of cross-case analysis to expose replication logic between the two selected samples, after which the findings were adjusted to form four analytical categories: the user’s understanding and knowledge of walking to the workplace; the use of mixed modes of transportation; physical features that support walking to work; and stakeholders’ involvement. The framework for this research was formed by these analytical categories to meet the research aims of finding ways to improve the employees’ walking experience in the pedestrian environment in the context of Kuala Lumpur city. The results showed that the public have a negative attitude towards walking to work. The data collected revealed that the decision employees make to drive is somewhat uninformed, as they lack a holistic understanding of the benefits of incorporating walking to work as part of their daily routine. A framework is developed which proposes that the current mind-set towards walking can be reversed if the data from the analytical categories mentioned earlier are effectively deployed to enchance the walking experience. The study emphasises on the increased knowledge and better understanding of the situation among the employees in order to choose a sustainable way to travel to and around the city centre. The framework also aims to achieve a holistic understanding of incorporating walking as part of mixed mode transportation to the workplace for a more impactful solution to long-distance trips, and to affect, in a positive manner, the mind-set of people who still depend on cars to commute to work in Kuala Lumpur city.
365

Isolation and characterization of a glycosaminoglycan with anticancer activity

Ogundipe, O. D. January 2015 (has links)
Glycosaminoglycans (GAGs) are a family of complex mixture of linear polysaccharides that are present in both vertebrates and invertebrates. This polysaccharide plays important roles in physiological and pathological conditions, including cancer. In this study, GAGs were isolated from two different fish (whelks and cockles) belonging to mollusc invertebrates. The crude GAGs isolated from each shellfish demonstrated variable selective anti-cancer activities against many cancer cell lines including breast (MDANQ01 and MDA468), leukemia (MOLT-4 and K562) and ovarian (HeLa) cancer. None of the commercial GAGs exhibited any anti-cancer activities against all the cancer cells studied. Previous studies conducted on the isolation of GAGs from molluscs reported mainly its anti-coagulant and anti-inflammatory activities; thus neglecting its record of anti-cancer activity. All purified whelk fractions (A – D & F) obtained failed to show any anti-cancer activity; with the exception of fraction E, which showed equal levels of selective anti-cancer activity against breast cancer cells. Mechanism of cell death caused by the three novel GAGs on cancers cells were investigated via cell cycle analysis and apoptosis detection assay. Cell cycle analysis revealed significant perturbations in the cancer cell cycle showing cell cycle arrests at different stages. Similarly, there were significant apoptosis inductions induced by the three novel GAGs on each of the cell lines investigated. Structural elucidations of the two fish GAGs, using chemical, enzymatic, Polyacrylamide, Superose 12 size exclusion chromatography , gel filtration and SAX-HPLC methods of analysis, revealed the presence of both chondroitin sulfate (CS)/dermatan sulfate (DS)-like and HS-like GAGs. Discrepancies in the structural elucidations of the novel GAG mixtures and the commercial GAGs may be partly responsible for the anti-cancer activity of the novel polysaccharides, as changes in exogenous GAGs structural composition, especially sulfation levels or patterns, can alter its binding to growth factors, which is essential for cell proliferation.
366

A theoretical framework to support facilities maintenance management of higher education institutions buildings in Nigeria

Olowoake, M. A. O. January 2015 (has links)
The processes required in maintaining Higher Education Institutions (HEIs) buildings, and to retain their services and facilities to an acceptable standard in Nigeria is being undermined by insufficient maintenance budget and lack of strategic planning. The aim of the study is to develop a new theoretical strategic framework to support Facilities maintenance management of Higher Education Institutions facilities in Nigeria. The key objectives of the study include: investigating the current theoretical approaches to facilities maintenance management, evaluating works and services departments’ constraints in relation to procurement strategies, maintenance methods, maintenance budgets, post occupancy evaluations, project quality control, sustainable programme, and the influence of culture on project execution. Others objectives include: developing a strategic framework to support facilities maintenance management, and validating its effectiveness and the efficiency. The scope of the study is focussed on the general maintenance of all building elements; services provided in the selected twelve HEIs in south west of Nigeria. The study adopted a mixed method research strategy by conducting series of semi-structured interviews with the directors of works and services of the selected HEIs, and a questionnaire survey of the 36 Technical Officers from the selected HEIs in Nigeria. The qualitative and quantitative data collected were analysed by using thematic analyses and multiple regressions respectively. The findings of the thematic analyses of the interviews reveal that, there was a general shortage of financial resources that allow keeping of backlogs of maintenance and repairs of HEIs buildings across both the federal and state HEIs. The work identified that, the following factors have caused majority of the backlogs of maintenance: low level of overall maintenance budget, delays in releasing cash (maintenance funds), lack of the adoption and use of planned prevent maintenance method, a shortage of in-house technical staff, and the absence of maintenance programmes and maintenance schedules. In addition, the findings of the questionnaire survey identified the largest and the strongest among the variables used (Predictor-Maintenance Budget), it determines the effectiveness and efficiency of the framework to about 58%, and determines at which level, that the smallest and less stronger variables can join together with the largest and strongest variable to make the framework effective in the facilities maintenance management of HEIs facilities in Nigeria. The findings further reveal that: majority of the HEIs works and services departments do not have full complements of technical staff, so they outsource most of their maintenance projects; most HEIs works and services departments do not have maintenance budgets; where the budgets are in place, they do not adopt appropriate techniques for data collection. In most HEIs sampled, the major defects are often caused by long delays in releasing maintenance cash. Other challenges include: use of inappropriate maintenance methods; lack of establishment of a project control unit within the works and services department; inability to prepare and use maintenance control toolkit; over reliance on complaints from the facilities users instead of carrying out post occupancy evaluations; and lack of adequate programmes to maintain the built environments under their management. A framework was subsequently developed to address the challenges and shortcomings discovered through interviews and the questionnaire survey. The key element of the framework is based on the extensive literature review and is the further validated through a series of interviews with senior technical officers from eight out of the twelve HEIs sampled. The interviewees agreed that the framework is valid, adaptable, and will make facilities maintenance management of HEIs facilities in Nigeria cost effective, efficient in running, and ensures the achievement of project quality control and project deliveries in a timely fashion. Key words: Backlog, budget, environment, sustainable, procurement, maintenance and quality.
367

A study of the performance of office workers descending multiple flights of stairs in high rise office buildings in trial evacuations

MacLennan, H. A. January 2013 (has links)
Aim: The Aim of this PhD study is to study the performance of mature age office workers descending multiple flights of stairs in trial evacuations of high rise office buildings in the context of extrinsic and intrinsic factors. Method: A case study process coupled with mixed methods data collection and analysis was selected with the unit of analysis being the office worker descending the stairs. An Exploratory case study involving the reanalysis of data from a similar study was undertaken to confirm the selection of the research method. Six high rise buildings were selected varying from 7 to 36 storeys . Trial evacuations were held and data collected via survey, observation and physical assessment. Two explanatory case studies involving a Delphi group and focus groups classified the main contextual issues as the intrinsic ones of the occupant and the extrinsic ones of Stair Design and Construction, Others on the Stairs and Management/ Maintenance. The other explanatory study comprised a directed content analysis of a two extremely relevant media documents related to multiple flight stair descent. The data was analysed and findings established by generalisation where trends could be explained quantitatively and otherwise via triangulation. Results and Conclusions: Fatigue predicting descent performance ability was determined by triangulation and generalisation. Density could mask fatigue as the result of delays that would allow people to descend at more slowly. Descent performance ability for 50% of the population was 300 metres in 1980 reducing to 240 metres in 2010. The risk of falling related directly to this distance and the spiralling action of turning at each landing . Triangulation showed this action increased the risk of vertigo and dizziness as well as the impact of increased BMI and health conditions on stability. The significant (p<.05) contextual extrinsic factors were found to be stair descent risk, need for clear visibility and support from reachable handrails, trial evacuation strategies and procedures and group dynamics. There are other less significant findings explained by context and the “cause and effect directed” case study research method.
368

Implementing green business models in the UK construction industry : opportunities and challenges

Abuzeinab, A. January 2015 (has links)
Green business models (GBMs) have the potential to deliver a much better performance compared to conventional business models (BMs) in this age of sustainability. The question of how construction companies can transform their BMs based on green value propositions is both highly relevant for management and poorly understood to date. This study empirically investigates GBMs transformations in the UK construction industry. The study closely scrutinises how GBMs are defined and understood by adopting a set of defined five elements from business and management literature: namely, green value proposition (GVP); target group (TG); key activities (KA); key resources (KR); and financial logic (FL). It also identifies changes, benefits, and challenges associated with GBMs to ultimately propose a guideline for GBMs implementation. It adopts a qualitative method to provide a diagnostic exploratory study and conducts 19 semi-structured interviews with academics and managers from various construction companies. This study applies thematic analysis as the main data analysis technique and further analyses and validates the findings by utilising interpretive structural modeling (ISM) and interpretive ranking process (IRP) techniques. ISM and IRP techniques are novel contributions to GBMs and construction research. The emergent findings are then validated and refined by conducting structured interviews with 4 academics and 1 director from a contractor practice. A BM is considered to be green when a business changes element (s) of its BM to create and capture a business opportunity or a proposition for TGs that provides environmental improvement coupled with economic benefits. The key findings reveal that GBMs can link environmental sustainability with economic success in a systematic manner. They show that GBMs transformations require strong change capabilities and radically influence the way in which companies conduct business. In addition, they demonstrate the interrelation between the different GBMs elements and show that the GVP and FL represent the foundation of GBMs. The challenges that emerged from this research include: government constraints; financial constraints; industry constraints; company constrains; and lack of demand. However, the ISM analysis demonstrates that government policies are the root challenges that hinder GBMs transformations. Despite the challenges posed, GBMs have the potential to deliver credibility, financial and long-term viability benefits for construction companies. The study proposes and validates a guideline for GBMs implementation for the UK construction industry. The guideline starts with creating top-management receptiveness and support the importance of capturing green demand to be converted into GVPs. It also stresses the importance of out-sourcing of some of the KA and KR and highlights the function of marketing and promotions. In addition, the guideline includes various reviewing and monitoring points to be fed to the top-management. Although the BMs and GBMs are new in the construction discipline, this research, as far as can be established, is one of the few empirical academic works introducing and defining GBMs in the construction context. This study contributes originally to GBMs research by developing a structured relationship between the different GBMs elements and by ranking the elements with reference to benefit areas. The relationship between the GBM elements informs construction managers that the smallest details are not vital in a GBM instead how every element of it fits together as a whole reinforcing system is important matter. Consequently, the different elements of the GBM should never be analysed or developed in isolation. To capture economic benefits offered by environmental sustainability, construction companies need to concentrate on greening the whole BM rather than products and processes only. Finally, the study draws a list of recommendations for increasing GBMs uptake and suggests further research opportunities, particularly in the areas of GBMs elements and networks. Key words: Business models, construction industry, environmental sustainability, green business models, UK.
369

Human response to environmental noise and vibration from freight and passenger railway traffic

Sharp, C. January 2014 (has links)
There is currently a push to increase the proportion of freight traffic that is transported by rail, which is argued to be a safer, more sustainable and more climate friendly means of freight transportation when compared with road or air transportation. This will result in increased noise and vibration from freight railway traffic, the potential impacts of which are not well known. The aim of this research, therefore, is to further the understanding of the human response to freight railway noise and vibration. Data for this research comes from a field study comprising interviews with respondents and measurements of their vibration exposure. A logistic regression model was created and optimised, and is able to accurately classify 96% of these measured railway vibration signals as freight or passenger signals based on two signal properties that quantify the duration and low frequency content of each signal. Exposure-response relationships are then determined using ordinal probit modelling with fixed thresholds and cumulative ordinal logit models. The results indicate that people are able to distinguish between freight and passenger railway vibration, and that the annoyance response due to freight railway vibration is significantly higher than that due to passenger railway vibration, even for equal levels of exposure. To further investigate this disparity in response, a laboratory study was performed in which subjects were exposed to combined noise and vibration from freight and passenger railway traffic. Through the technique of multidimensional scaling, the subjective responses to these stimuli were analysed to investigate the specific attributes of the stimuli that may lead to the difference in human response. The results of this study suggest that the perception of combined railway noise and vibration takes into account not only the exposure magnitude of the noise and vibration stimuli, but also signal properties such as duration, spectral distribution and envelope modulation. These parameters, and in particular the duration parameter, appear to account for the difference in the human response to freight and passenger railway vibration.
370

Genotoxicity of the space environment

Khaidakov, Magomed 30 October 2017 (has links)
This thesis presents a study on possible genetic consequences of the exposure to the space environment during space missions The present study was undertaken in co-operation with the Canadian Space Agency, and involved the analysis of the lymphocyte samples taken from experienced cosmonauts and trainees. For the analysis of genotoxicity of the space environment, a T-lymphocyte hprt clonal assay has been employed. In order to distinguish between artefacts associated with this method and the spaceflight-related effects, we have conducted a series of in vitro reconstruction experiments. In these experiments we have analysed interactions between plating efficiency (PE) of T-lymphocytes and efficiency of mutant recovery. Using 12 pairs of independent wild type (WT) and mutant clones, we have demonstrated an inverse correlation between initial viability of the WT cells and survival of mutant cells (r = 0.3496, p < 0.05). Our data suggest that the presence of WT cells in the selection plates does suppress the recovery of mutants in HPRT assay. This effect is stronger in samples with high PE, and may be a source of large error in estimation of mutant frequencies (approx. 3-fold in the range of PEs from 10% to 60%), which is especially relevant when samples with different PEs are compared. Analysis of samples from cosmonauts was conducted in two experiments. The first experiment involved 5 samples taken in 1992 from cosmonauts who have completed spaceflights ranging in duration from 7 to 365 days. Hprt mutant frequencies (MF) in these samples were 2.5–5 times higher than the age-corrected values for healthy, unexposed subjects in Western countries (Tates et al., 1991; Branda et al., 1993), and 2-3-fold higher than those determined for unexposed individuals residing in Russia (Jones et al., 1995). The cosmonaut mutational spectrum differed from that of unexposed healthy subjects (p = 0.042), and showed a higher incidence of splicing errors, frameshifts, and complex mutations. Distribution of base substitutions was remarkably similar to that observed in Russian twins sampled at the same period (Curry et al., 1998), thus suggestive of possible environmental, diet, or life-style related exposures. The second study was conducted on samples taken 5 years later and involved trainees and a group of cosmonauts with more uniform (at least 6 months) and recent flight experience. Hprt MFs in both cosmonaut and trainee groups were virtually identical (17.2 ± 0.6 and 17.6 ± 4.7 × 10⁻⁶ respectively), and approximately 2-fold higher than in matching Western controls, although considerably lower than in our previous observations. Mutational spectra in both datasets were very similar to that observed in our earlier study, and were significantly different from spontaneous data (p = 0.031–0.038). Distribution of base substitutions, however, did not show any differences. Our data indicate that the space environment is not genotoxic at the hprt locus. At the same time, uniformly high MFs observed in all studied groups suggest that the level of the mutagenic burden in at least megalopolis areas of Russia may be considerably larger than in the West. Also, there are some indications of a possible restructuring of mutagenic burden in post-transitional Russia. / Graduate

Page generated in 0.0643 seconds