• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 63
  • 33
  • 11
  • 9
  • 6
  • 4
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 161
  • 161
  • 28
  • 28
  • 17
  • 15
  • 15
  • 15
  • 15
  • 15
  • 14
  • 13
  • 13
  • 12
  • 11
  • 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.
11

From Conventions To Creative A Conceptual Model Of Multicultural eams¡¦Divergence and Convergence

Wu, Chengyu 19 January 2006 (has links)
When a multicultural team is formed of say six individuals of different cultural backgrounds, there will be potential conflicts and greater varieties. However, there will be a ¡§normal¡¨ curve forms the range and permissible boundaries of a team. In concept, this normal distribution is the ¡§calm¡¨ state when the team is not active (norms). The potential is the range of team members¡¦ abilities/differences (divergences). To be able to reach the potential and perform is part of the team¡¦s goal (convergences & attributions). But to expect something more than expected is cultural synergy (break the original boundaries). The factors that will be considered as diverging forces are the differences that are born (already exists) when the team is formed. In order to model these cultural factors and estimate these cultural differences, Hofstede cultural dimensions are used. The factors that will be considered as converging forces are what each individual believe in such as perspective taking and self-leadership. These values are projected from the assessments of team individuals. The factors that will be considered as supporting forces (attribution factors) are how each member interacts with one another during the process. These are each individual behavior and personality. Therefore, from the perspective of divergence and convergence to see how cultural differences influence the teams and talk about their possible behaviors and reasons behind them is a conceptual way to look at the team. Based on the concept described above, the analysis of these different forces on multicultural teams is conducted. Using these factors, the paper explains/examines: l Cultural and individual values differences l Wish to base on the findings from the research to make helpful inferences on the learning and performance of multicultural teams. l Cultural divergent factors l Individual convergent factors l Individual attribution factors l Cultural synergy
12

A Study On Conceptual Modeling In Simulation Systems: An Extended Methodology For Kama

Aysolmaz Bozlu, Banu E. 01 December 2007 (has links) (PDF)
Conceptual modeling is considered to be essential in simulation development activities. However, there are only a few research studies on how to develop conceptual models. One of the important and comprehensive approaches is the methodology developed under the leadership of METU Modeling and Simulation Center (MODSIMMER) for Turkish Armed Forces. The project suggests a methodology to develop mission space conceptual models (GUKAM), and provides a Conceptual Model Development Tool for C4ISR M&amp / S activities, which is named as KAMA-C4ISRMOS. KAMA methodology is developed to utilize conceptual models in requirements collection and analysis activities. Two improvement opportunities observed in KAMA approach are that, there are no methodologies defined to develop simulation space conceptual models / and although most approaches emphasize the importance of conceptual model to be used in design activities, no explanations are provided on how to do it. This thesis aims to suggest an extended KAMA methodology that, besides original KAMA properties, provides a method to develop simulation space conceptual model, and provides a guide to use conceptual model to develop design. To evaluate the suggested methodology, a case study is conducted on a synthetic environment project. In this way, implementation of the methodology on another simulation domain is depicted. Developed mission space and simulation space conceptual models and design artifacts are evaluated, and the effects of conceptual models on simulation development life cycle are discussed.
13

An integrated hydrogeological/hydrogeochemical approach to characterising groundwater zonations within a quaternary coastal deltaic aquifier: The Burdekin River delta, North Queensland.

McMahon, Gerard Armstrong January 2004 (has links)
Despite being one of the largest aquifers of its type in Australia, the Burdekin River Delta (BRD) is an area that has received comparatively little research on its groundwater resources. This study conceptualises the hydrogeology of the BRD and characterises the relationships between the stratigraphic elements and the physical and chemical components of the groundwater system that influence the major governing processes. Importantly, a large amount of spatial and temporal groundwater information exists in database form, which enables an integrated conceptual model of the BRD aquifer to be developed from the key hydrogeological and hydrogeochemical relationships. Conceptualisation of the BRD aquifer is achieved by categorising four main aspects of the groundwater resource: 1. Surface characterisation; 2. Geologic characterisation; 3. Hydrogeologic characterisation; and 4. Groundwater System characterisation. The BRD is a large cuspate delta comprising a complex stratigraphy of Pleistocene to Holocene sediments of fluvial, deltaic and marine origin to a maximum depth of about 150 metres. The lower Pleistocene sediments lie predominantly below sea level and are typified by laterally discontinuous sands, silts and clays that have formed in response to fluctuating sea levels. The upper Pleistocene boundary is differentiated from the overlying Holocene sediments by a formerly exposed surface of semiconsolidated oxidised sandy clays and gravel. By contrast, the Holocene sediments comprise loose, uncompacted sequences of fluvial channel sands, interdistributary floodplain silts and marine incursions of estuarine clays and mangrove muds. The anastomosing array of fluvial sand bodies of former Burdekin River channels and levees is the setting for the main shallow aquifer units. Aquifer units of the lower Pleistocene sediments are in hydraulic connection with the Holocene units, effectively categorising the whole BRD as a single unconfined aquifer. Hydraulic gradients from both sides of the river divide the BRD into two broad flow regimes. Interpreted flow zones based on hydrograph patterns further subdivide the flow system based on seasonal recharge response to elevated river heights and flooding, and response to long-term rainfall patterns associated with La Niña episodes of the Southern Oscillation. Stable isotope data (2H and 18O) indicate that the dominant isotopic signature of groundwater throughout the BRD corresponds with intense rainfall activity, however high deuterium-excess values indicate that significant evaporation occurs prior to recharge. This infers dominant recharge by the Burdekin River that drains a massive catchment extending hundreds of kilometres inland. Direct recharge via rainfall infiltration is largely dependant on soil texture. More conductive soils are associated with the major levee systems that comprise the main shallow aquifers. Two evolutionary hydrogeochemical paths exist for the north and south sides of the river, and are constrained by the interpreted flow zones. In the south side, groundwater enters the main aquifer from river recharge and leakage out of weathered granite outcrops (exposed bedrock). Mineral hydrolysis and evaporative concentration of salts initially evolve groundwater in the weathered granite to a combination of Na-Cl and Na-HCO3 type. Leakage through clay-rich hillwash and marginal sediments causes reverse cation-exchange reactions where excess Na replaces Ca and Mg on ion-exchange surfaces. This leads to the formation of Mg,Ca-Cl type groundwaters into the southern parts of the main aquifer (supersaturated with respect to calcite and dolomite). Discharge towards the coast is characterised by seawater mixing where salinity increases with corresponding evolution to Na-Cl type waters. Recharge waters from the Burdekin River are fresh (<250mS/cm) Ca-HCO3 type, undersaturated with respect to calcite, and are easily distinguishable from the ion-exchange groundwater. In the north, only one smaller outcrop of bedrock exists, which hosts similar mineral hydrolysis reactions and base-exchange reactions. An absence of associated Na-Cl type waters means that reverse-cation exchange reactions are negligible, and so water types are predominantly Na-HCO3 type. Aquifer sands in the north are more widespread than in the south, so the fresh Ca-HCO3 recharge waters tend to dominate the overall groundwater composition, with Na-HCO3 types limited to the exposed bedrock areas. Towards the coastline, groundwater mixes with seawater towards Na-Cl type waters, similar to that observed in the south. The mangrove mud sequences that flank the coastline of the BRD are associated with high-Fe and low-pH groundwater formed by the oxidation of Fe-sulphides such as pyrite). SO4 is a product of this reaction, but does not achieve abnormally high concentrations, possibly due to the presence of sulphate-reducing bacteria. Carbonate dissolution is a possible side effect of acid sulphate generation, with possible gypsum dissolution as a secondary source of SO4. This study tested an alternative method to characterising groundwater to determine if the spatial extent of hydrogeochemical processes could be defined and comparable results achieved. This method involved discriminating discrete statistical groups of ionic ratios based on their cumulative frequency distribution. The statistical groups are bounded by critical values that distinguish different chemical processes, referred to as hydrogeochemical indicators. Various tested ionic ratios produced analogous indicators, proving their reliability as a valid method for the characterisation of groundwater chemistry. The significance of this research underlies the importance of groundwater use in the BRD as a primary source of irrigation supplies. Land use expansion and unregulated pumping pose a risk to future groundwater quality and sustainable volumes. The understanding of the relationship between the main geologic elements and the subsequent hydrogeochemical processes provides a scientific basis for conceptualising the groundwater resource. This establishes a framework for initiating future groundwater management options.
14

Hydrogeology, Conceptual Model and Groundwater Flow Within Alluvial Aquifers of the Tenthill and Ma Ma Catchments, Lockyer Valley, Queensland

Wilson, Andrew Scott January 2005 (has links)
The study focuses on the adjacent Tenthill and Ma Ma catchments which converge onto the heavily cultivated alluvial plain of Lockyer Creek. Groundwater extracted from the alluvial aquifers is the primary source of water for intensive irrigation. Within the study the hydrogeology is investigated, a conceptual groundwater model produced and a numerical groundwater flow model is developed from this. The hydrochemistry and stable isotope character of groundwater are also investigated to determine processes such as recharge and evaporation. Examination of bore logs confirms the Quaternary alluvium comprises a laterally continuous gravel aquifer with an average thickness of 4.5 m, overlain by mixed sands and clays which form a semi-confining layer with an average thickness of 22 m. Variations in long term groundwater hydrographs indicate the aquifer changes from confined to unconfined in some locations as water levels drop, while bores adjacent to creek banks display a rapid response to a flood event. Pump testing of bores screened in the gravel produces estimates of hydraulic conductivity ranging from 50-80 m/day and storativity of 0.00166 which are both within realistic bounds for this aquifer material. Major ion chemistry of surface water collected during a flood is Mgdominated, similar to alluvial groundwater in the Tenthill catchment and the Lockyer plain, suggesting a strong connection between surface and groundwater in these locations. Alluvial groundwater salinity in Tenthill catchment is typically less than 3500 ìS/cm but may approach 6000ìS/cm on the Lockyer plain. By contrast Ma Ma catchment alluvial groundwater is Na-dominated with conductivity up to 12000 ìS/cm and more associated with groundwater from the underlying sandstone bedrock. Stable isotope analyses of alluvial groundwater from throughout both catchments and the Lockyer plain are compared with basalt and sandstone groundwater. A range of processes have been identified including recharge to alluvium from basalt groundwater and evaporated surface water; and alluvial-bedrock groundwater mixing at some locations. Integration of the components of the study enabled the production of a conceptual hydrogeological model of the Lockyer alluvial plain, proposing two hydrostratigraphic units; the gravel aquifer and the overlying mixed sand and clay which acts as a semi confining unit. Hydrochemical and stable isotopic evidence suggests seepage from creek channels as the dominant recharge process. A single layer groundwater flow model using MODFLOW was developed, based on groundwater extraction data, to represent flow in the gravel aquifer. The model was calibrated to transient conditions with groundwater fluctuations, incorporating both drought and flood conditions. A sensitivity analysis for each of the aquifer properties demonstrates the model is insensitive to variations within realistic bounds for the gravel aquifer material, however, the model is highly sensitive to changes in the chosen boundary conditions. Predictive simulations with several annual extraction scenarios ranging from 1.75 to 0.5 ML/ha indicate the resulting minimum saturated aquifer thickness ranges from 0.03 to 1.4 m.
15

The Southeastern Illinois Prescribed Burn Association: Spearheading Land Management Coalitions in the Midwest

Riechman, Jesse Avery 01 August 2012 (has links)
Fire in Midwestern ecosystems historically has provided many benefits, including promoting forest succession, maintaining wildlife habitat and reducing fuel loads. The Southeastern Illinois Prescribed Burn Association (SIPBA) is the only association of its kind in southern Illinois, designed to reintroduce prescribed fire to landowners in a practical context. The objectives of this research project were: 1) Interview members and crewpersons to collect data on the formation, maintenance, and future of SIPBA, 2) Outline the most common/salient issues driving landowners and stakeholders concerning the use of prescribed fire on their land in southern Illinois, and 3) Provide a conceptual model of the results to serve as a guide for future development of publicly conducted and implemented prescribed burning activities across southern Illinois and, ultimately, the Midwest. This study was implemented by semi-structured interviews of 28 key members of SIPBA. The responses from this population were collected and coded using NVivo 9 qualitative analysis software (NVivo 9 2011). Results indicate that challenges include stubborn remnants of the "Smokey Bear" attitude from the U.S. Forest Service anti-fire campaign, and that liability for an escaped wildfire is a reality for both the individual and for the association. In spite of these and other challenges identified by participants, landowners see SIPBA as a cost-effective solution to their land management needs. The results were interpreted as guidance for future dialogue between landowners and stakeholders and state and federal agencies in implementing prescribed burning programs. Implications include: "fire sells itself." Relatively little effort is needed to attract interest and recruit membership, and the benefits of a prescribed burn are easily evident. Alleviating concerns of the risks associated with fire is a primary objective for the organization, and there is a feeling of "safety in numbers" among membership. Finally, outside funding appears to be the limiting factor for both the capacity and potentially the longevity of the association, meaning that the development of a sustainable funding scheme could allow prescribed burn associations to remain in the Midwest. This case study of SIPBA membership is intended to facilitate cooperation between landowners and local burn associations, and also to serve as a model for the formation of future associations in similar areas of the Midwest.
16

Developing a hydrogeological conceptual model for subterranean groundwater control areas using remote sensing techniques, Hout catchment, Limpopo, South Africa

Mkali, Andrew Talinda January 2020 (has links)
>Magister Scientiae - MSc / Crystalline basement aquifers are an important source of water supply in sub-Saharan Africa for various purposes. These aquifers are characterized by fractured rock networks which form pathways for groundwater recharge, flow, and discharge in subterranean groundwater areas. The fractured rock networks in these areas form fractured rock aquifers which in some cases are protected or reserved. In South Africa, various aquifers with these characteristics have been declared as subterranean groundwater control areas. The physical characteristics of these hydrogeological settings remains crucial in sustaining ecosystems and supporting socio-economic practices such as irrigation, among others. However, the role of fracture connectivity in crystalline basement aquifers remains poorly understood despite the well-established knowledge about the hydrogeological characteristics of such areas. / 2022
17

THE IMPACT OF UNEXPECTED ADVERTISING TACTICS ON SOURCE VERSUS PRODUCT EVALUATIONS: A CONCEPTUAL MODEL AND EMPIRICAL TEST

ROBERTSON, BRUCE C. 11 October 2001 (has links)
No description available.
18

An Inspection Approach For Conceptual Models Of The Mission Space In A Domain Specific Notation

Tanriover, O. Ozgur 01 October 2008 (has links) (PDF)
An inspection approach is proposed for improving the quality of conceptual models developed in a domain specific notation. First, the process of identification of desirable properties of conceptual models in a domain specific notation is described. Intra- and interview properties are considered. Semantic properties are defined considering the conceptual modeling notation. A systematic inspection process is proposed for checking semantic properties of different types of diagrams and of the relations between these diagrams. This process is applied to two real mission space conceptual models. With the proposed inspection approach, it is possible to identify subtle semantic issues which are not identified by many of the contemporary UML CASE tools and other inspection methods.
19

A methodology for the development of models for the simulation of non-observable systems

Turner, Andrew J. 22 May 2014 (has links)
The use and application of modeling and simulation (M&S) is pervasive in today's world. A key component in the application of models is to conduct appropriate verification and validation (V&V). V&V is conducted to make sure the model represents reality to the appropriate level of detail based on the questions posed. V&V techniques are well documented within the literature for observable systems, i.e. required data can be collected from the operations of the real system for comparison with the simulation results; however, V&V techniques for non-observable systems are limited to subjective validation. This subjective validation can be applied to the simulation outputs, operational validation, or towards the model development, conceptual validation. Oftentimes subjective operational validation of the simulation is the primary source of validation efforts. It is shown in this thesis that the sole reliance on subjective operational validation of the simulation can easily lead to the inaccurate acceptance of a model. In order to improve M&S practices for the representation of non-observable systems, models must be developed in a methodological manner that provides a traceable and defensible argument behind the model’s representation of reality. Though there is growing discussion within the recent literature, few methods exist on proper conceptual model development and validation. The research objective of this thesis is to identify a methodology to develop a model in a traceable and defensible manner for a system or system of systems that is non-observable. To address this research objective the proposal will address eight aspects of model development. The first is to define a set of terms that are common vernacular in the field of M&S. This is followed by the assessment of what defines a ‘good’ model and how to determine if the model is ‘good’ or not. This leads to a review of V&V and the observation that subjective validation in isolation is not sufficient for model validation. Next, a review of model development procedures is conducted and analyzed against a set of criteria. A selection is made using the Analytic Hierarchy Process (AHP). A procedure developed by Balci in 1986 is selected for the use in development of models for non-observable systems. Specific steps within Balci's 1986 procedure are investigated further to determine appropriate techniques that should be used when developing models of non-observable systems. These steps are system and objective definition, conceptual model, communicative model, and experimental models and results. Five techniques are identified in the literature that can be applied to system and objective definition: Soft Systems Methodology, Requirements Engineering, Unified Modeling Language, Systems Modeling Language, and Department of Defense Architecture Framework. These techniques are reviewed and selection is made using AHP. The System Modeling Language (SysML) is selected as the best technique to perform System an Objective Definition. Significant resources are devoted to the study of conceptual model development. Proposed in this thesis is a process to decompose the impacts of the system and apply subjective weightings in order to identify aspects of the system with significant importance. This approach enables the modeling of the system in question to the appropriate level of fidelity based on the identified importance of the system impacts. Additionally, this process provides traceability and defensibility of the final model form. Communicative model development is rarely addressed in the literature; however, many of the techniques used in system and objective definition can be applied to developing a communicative model. A similar study to the system and objective definition, AHP was utilized to make a selection. It was concluded that the Unified Modeling Language provides the best tool for creating a communicative model. In the final step, experimental models and results, the literature was found to be rich in techniques. A gap was found in the analysis of the outputs of stochastic simulations. Four questions resulted: 'which stochastic measures should be used in analyzing a stochastic simulation?', 'how many replications are required for an accurate estimation of the stochastic measure?', which least squares method should be used in the regression of a stochastic response?, and 'how many replications are required for an accurate regression of a stochastic measure? Heuristics are presented for each of these questions. A proof of concept is provided on the methodology developed within this thesis. The selected scenario is a Humanitarian Aid/Disaster Relief Mission, where the U.S. Navy has been tasked with distributing aid in an effective manner to the affected population. Upon application of the proposed methodology, it was observed that subjective decomposition and weighting of the scenario proved to be a useful tool for guiding and justifying the form of the eventual model. Shortcomings of the methodology were identified. The primary shortcomings identified were the linking of information between the steps of the model development procedure, and the difficulty in correctly identifying the structure of the system impacts decomposition. The primary contribution of this thesis is to the field of M&S. Contributions are made to the practice of conceptual model development, a growing discussion within the literature over the past several years. The contribution to conceptual model development will aid in the development models for non-observable systems. Additional contributions are made to the analysis of stochastic simulations. The methodology presented in this thesis will provide a new and robust method to develop and validate models in a traceable and defensible manner.
20

Treatment satisfaction and dissatisfaction in patients with chronic low back pain

Rofail, Diana January 2010 (has links)
This thesis explores treatment satisfaction and dissatisfaction in patients with chronic low back pain (CLBP). Chapters 1 and 2 provide background on CLBP, and treatment satisfaction and dissatisfaction. Chapter 3 presents study 1, the systematic review which identified research concerning treatment satisfaction and dissatisfaction in patients with CLBP. Findings indicated a need to define the concept, and establish appropriate measurement based on patient input and evidence to support the reliability and validity of items. Chapter 4 presents study 2, a qualitative study. Ten patients with CLBP taking medication and/or receiving physiotherapy were interviewed. A conceptual model of CLBP and a thematic map of treatment satisfaction and dissatisfaction were developed. Satisfaction was related to being 'happy' or 'pleased', and maintaining normal functioning. Treatment not working, causing discomfort, or negatively affecting health-related quality of life, as well as inconvenience of medication, lack of information, not feeling involved in treatment decisions, lack of trust and confidence in healthcare professionals, and being misdiagnosed or undiagnosed, were associated with dissatisfaction. Chapter 5 documents the development of the CLBP Treatment Satisfaction Questionnaire, based on patient input from study 2. Cognitive debriefing showed items were relevant and understood by patients. Chapter 6, study 3, explored the psychometric properties of the questionnaire. The longitudinal design involved data collection from 249 patients, some of whom participated in follow-ups. Results indicated that treatment satisfaction/dissatisfaction involves an appraisal of the following seven domains: 'Information Provided about Back Pain and Treatment', 'Burden of Back Pain', 'Impact of Back Pain and Treatment on Relationships', 'Satisfaction with the Treatment Process', 'Problems with Side Effects of Medication', 'Adherence to Physiotherapy', and 'Medication Acceptability'. Some evidence of reliability and validity are presented. This thesis concludes with Chapter 7, a discussion of the main findings of the studies, strengths and limitations, and recommendations for future research.

Page generated in 0.0747 seconds