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  • 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

Multibody dynamics based simulation studies of escapement mechanisms in mechanical watch movement.

January 2008 (has links)
Fu, Kin Chung Denny. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 119-123). / Abstracts in English and Chinese. / Abstract --- p.i / 摘要 --- p.iii / Acknowledgements --- p.iv / Table of Contents --- p.v / List of Figures --- p.viii / List of Tables --- p.xi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Objective --- p.1 / Chapter 1.2 --- Fundamental knowledge of multibody dynamics --- p.2 / Chapter 1.3 --- Escapement mechanisms --- p.5 / Chapter 1.3.1 --- Time keeping accuracy and stability factors --- p.7 / Chapter 1.3.2 --- Estimations of moment of inertia --- p.9 / Chapter 1.3.3 --- Other simulations and analyses --- p.15 / Chapter 1.4 --- Thesis outlines --- p.15 / Chapter 1.5 --- Chapter summary --- p.17 / Chapter Chapter 2 --- Multibody Dynamics --- p.18 / Chapter 2.1 --- The unilateral corner law of impact --- p.18 / Chapter 2.2 --- The Coulomb's friction --- p.19 / Chapter 2.3 --- "Slip, stick, and slip reversal phenomena" --- p.20 / Chapter 2.4 --- The coefficients of restitution --- p.20 / Chapter 2.5 --- Ways of formulating multiple contacts --- p.22 / Chapter 2.6 --- Integration procedure --- p.22 / Chapter 2.7 --- The P. Pfeiffer and Ch. Glocker's approach --- p.23 / Chapter 2.7.1 --- Kinematics calculation --- p.23 / Chapter 2.7.2 --- Configuration index --- p.26 / Chapter 2.7.3 --- Motion without contact --- p.27 / Chapter 2.7.4 --- Motion for detachment and slip-stick transition and LCP formulation --- p.27 / Chapter 2.7.5 --- Motion for impact and LCP formulation --- p.37 / Chapter 2.8 --- Solving LCP --- p.50 / Chapter 2.9 --- Chapter summary --- p.52 / Chapter Chapter 3 --- Development of the Simulation Tool --- p.54 / Chapter 3.1 --- Kinematics calculation --- p.54 / Chapter 3.1.1 --- Geometric definitions --- p.55 / Chapter 3.1.2 --- Line-to-line contact --- p.59 / Chapter 3.1.3 --- Arc-to-line contact --- p.62 / Chapter 3.1.4 --- Kinematics calculation procedures --- p.67 / Chapter 3.2 --- Obtaining the solutions --- p.72 / Chapter 3.3 --- Revised numerical treatment for LCP solving --- p.73 / Chapter 3.4 --- Integration procedure of simulation --- p.74 / Chapter 3.5 --- Verification example --- p.76 / Chapter 3.5.1 --- Classical mechanics approach --- p.76 / Chapter 3.5.2 --- Pre-calculation before application --- p.79 / Chapter 3.5.3 --- Simulation results --- p.81 / Chapter 3.6 --- Chapter summary --- p.83 / Chapter Chapter 4 --- Application to Swiss Lever Escapement --- p.84 / Chapter 4.1 --- Working principle of Swiss lever escapement --- p.84 / Chapter 4.2 --- Simulation of Swiss lever escapement --- p.87 / Chapter 4.2.1 --- Pre-calculation of kinematics --- p.88 / Chapter 4.2.2 --- Simulation results --- p.89 / Chapter 4.3 --- More simulations --- p.102 / Chapter 4.3.1 --- Theoretical optimal peak amplitudes --- p.102 / Chapter 4.3.2 --- Simulation of coaxial escapement --- p.103 / Chapter 4.3.3 --- Simulations with different simulation parameters --- p.109 / Chapter 4.3.4 --- Relation of input complexity and computational time --- p.111 / Chapter 4.4 --- Chapter summary --- p.113 / Chapter Chapter 5 --- Conclusions and Future works --- p.114 / Chapter 5.1 --- Conclusions --- p.114 / Chapter 5.2 --- Future works --- p.117 / Bibliography --- p.119
12

A comparative analysis of the marketing effectiveness of Japanese watches and Swiss watches in Hong Kong.

January 1980 (has links)
by Fung Pui-wing. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1980. / Bibliography: leaves 220-224.
13

The development of consumer behavior models for watches in Hong Kong.

January 1972 (has links)
Liu Kam-hong. / Summary in Chinese. / Thesis (M.B.A.)--Chinese University of Hong Kong. / Bibliography: leaves 126-130.
14

Identity and Institutional Change in a Mature Field: The Re-emergence of the Swiss Watchmaking Industry, 1970-2008

Raffaelli, Ryan L. January 2013 (has links)
Thesis advisor: Mary Ann Glynn / This dissertation examines the decline and re-emergence of the Swiss mechanical watch industry from 1970-2008, exploring how, when, and why market demand for legacy technologies resurrect and reshape a mature field. Extending existing research on technology emergence and death, I reveal the dynamics of technology and field re-emergence. I focus on the mechanisms of identity and institutional change associated with re-emergence, as well as how institutional leaders and guardians serve as agents of change who simultaneously preserve and reframe the values and product conceptions associated with a legacy technology. Additionally, I advance the notion of identity ambidexterity by examining how organizations explore and exploit multiple elements of their identity simultaneously during such periods of instability. Using qualitative and quantitative methods, I analyze a wide range of interview, archival, historical, and observational data at the levels of the industry and the organization. More broadly, I seek to demonstrate how the reclamation of legacy identities reshapes the institutional environment of a mature field, and how incumbent firms re-define their organizational identities after a technological innovation threatens to destroy their dominant market position. / Thesis (PhD) — Boston College, 2013. / Submitted to: Boston College. Carroll School of Management. / Discipline: Management and Organization.
15

Ergonomia cognitiva do uso de relógio inteligente durante condução simulada de automóvel : movimento dos olhos e desempenho de motoristas experientes e novatos /

Silva, Gustavo de Andrade. January 2018 (has links)
Orientador: Sérgio Tosi Rodrigues / Banca: Luis Carlos Paschoarelli / Banca: Renato de Moraes / Resumo: O relógio inteligente é um novo tipo de eletrônico para o punho com funcionalidades idênticas as de um celular, que também é utilizado por motoristas durante a tarefa de condução do veículo, representando uma nova forma de distração do motorista, e risco aumentado de acidentes no trânsito; uma demanda da ergonomia cognitiva. O objetivo do presente estudo foi determinar o efeito do uso de relógio inteligente sobre motoristas experientes e novatos durante a condução simulada de automóvel, na tarefa de seguir o automóvel à frente, através da análise de movimento dos olhos, da cabeça e do desempenho na condução. Vinte motoristas experientes (EXP) e vinte motoristas novatos (NOV) realizaram a tarefa de seguir um carro à frente por um percurso de 2 km em quatro condições: somente seguir o carro (CAR), seguir o carro e receber uma notificação de texto no relógio inteligente (NOT), seguir o carro que freará de modo inesperado e brusco (FRE) e seguir o carro que freará de modo inesperado e brusco e, adicionalmente, receber uma notificação de texto (FNOT). Os dados do olhar, da cabeça e do desempenho na condução do automóvel foram submetidos à análise de variância de grupo (EXP, NOV) por condição de freada (CAR, FRE) por condição de notificação (NOT, FNOT) por tentativa (1, 2, 3). O desempenho da condução de veículo foi afetado pela freada do carro à frente e pelo uso do relógio inteligente ao receber notificação. Ao receber uma notificação no relógio, mudava-se o foco atencional do tr... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Smartwatch is a new kind of electronic to be worn on the wrist with features similar to those of mobile phones, they are also being used by drivers during their driving task, representing a new form of distraction for drivers and increasing chances of traffic accidents. The goal of this project is to determine the use effect of smartwatches on experienced and novice drivers while driving on a simulated driving task following a vehicle ahead, through the analysis of eye and head movement and driving performance in a driving simulator. Twenty experienced drivers (EXP) and twenty novice drivers (NOV) will follow a car ahead for 2 kilometers in four conditions: follow a car ahead (CAR), follow a car ahead and receive a text message notification on the smartwatch (NOT), follow a car ahead that brakes abruptly (FRE) and follow a car ahead and receive a text message notification on the smartwatch while the car ahead brakes abruptly (FNOT). The gaze, head movement and driving performance data will be subjected to group variance analysis (EXP, NOV), with or without braking (CAR, FRE), with or without smartwatch notification (NOT, FNOT) and by trial (1, 2, 3). The diver's performance showed to be affected by the car's ahead braking and by the use of smartwatch during reading tasks. Attentional focus was shifted away from the road to the smartwatch when drivers tried to perform the reading task, thus increasing the chances of an accident. Experienced and novice drivers used different st... (Complete abstract click electronic access below) / Mestre
16

Design and implement a micro assembly machine for mechanical watch movements.

January 2009 (has links)
Yang, Fan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 73-77). / Abstracts in English and Chinese. / Abstract --- p.I / 摘要 --- p.III / Table of Contents --- p.V / List of Figures --- p.i / List of Tables --- p.A / Chapter 1. --- Introduction --- p.1 / Chapter 1.1. --- Literature Review --- p.1 / Chapter 1.2. --- Project Background --- p.10 / Chapter 1.3. --- Objectives --- p.14 / Chapter 2. --- Design of the micro assembly machine --- p.16 / Chapter 2.1. --- Aspects that need to be met --- p.16 / Chapter 2.2. --- Hardware of the micro assembly machine --- p.17 / Chapter 2.2.1. --- The vision system --- p.18 / Chapter 2.2.2. --- The control system --- p.19 / Chapter 2.2.3. --- The Actuating System --- p.21 / Chapter 2.2.3.1. --- The gripper --- p.22 / Chapter 2.2.3.2. --- The three axes --- p.28 / Chapter 2.2.3.3. --- The workbench --- p.31 / Chapter 2.2.4. --- The complete structure of the micro assembly machine --- p.32 / Chapter 2.3. --- The main features of the micro assembly machine --- p.34 / Chapter 3. --- Implementation --- p.35 / Chapter 3.1. --- Vision system --- p.35 / Chapter 3.2. --- Setting up the vision system --- p.36 / Chapter 3.3. --- Efficiency and form of the transferred data --- p.38 / Chapter 3.4. --- Control system --- p.39 / Chapter 3.4.1. --- Structure of the control system --- p.40 / Chapter 3.4.2. --- System control process --- p.44 / Chapter 3.4.3. --- The GUI --- p.45 / Chapter 3.4.4. --- Data processing --- p.48 / Chapter 3.5. --- Cooperation between the vision system and the control system --- p.49 / Chapter 4. --- Experimental results --- p.51 / Chapter 4.1 --- Accuracy in the x and y directions --- p.51 / Chapter 4.2 --- Effect of the vision system on accuracy --- p.57 / Chapter 4.3 --- Depth of the assembled ruby bearings --- p.62 / Chapter 4.4 --- Gradient of the rubies --- p.65 / Chapter 4.5 --- Analysis of the experimental data --- p.68 / Chapter 5 --- Conclusion and Future Work --- p.70 / References --- p.73
17

Milli-meter-scale turning centre: theory and implementation.

January 2007 (has links)
Chan, Ngai Shing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 67-70). / Abstracts in English and Chinese. / Abstract --- p.I / 摘要 --- p.III / List of Figures --- p.VI / List of Tables --- p.VIII / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background Information --- p.2 / Chapter 1.1.1 --- Project Background --- p.2 / Chapter 1.1.2 --- Literature Review --- p.4 / Chapter 1.1.3 --- Background on Gear Hobbing --- p.10 / Chapter 1.1.4 --- Traditional gear hobbing machines --- p.12 / Chapter 2 --- Design and Testing of the MMT system --- p.15 / Chapter 2.1 --- Specifications of the MMT system --- p.16 / Chapter 2.1.1 --- Overall Configuration --- p.18 / Chapter 2.1.2 --- Linear Actuation --- p.18 / Chapter 2.1.3 --- Main Spindle Assembly --- p.19 / Chapter 2.1.4 --- Tool Plate Assembly --- p.20 / Chapter 2.1.5 --- Motion Control --- p.22 / Chapter 2.2 --- Main Features --- p.24 / Chapter 2.2.1 --- Mechanically Decoupled Gear Hobbing --- p.24 / Chapter 2.2.2 --- Single Setup for Non-planar Gears --- p.26 / Chapter 2.2.3 --- Quality Assurance by Computer Simulation --- p.27 / Chapter 2.3 --- Turning Test --- p.28 / Chapter 2.3.1 --- Experiment Results --- p.29 / Chapter 2.3.2 --- Tornos' Performance --- p.30 / Chapter 2.3.3 --- Estimation of Cutting Force and Workpiece Deflection --- p.32 / Chapter 2.4 --- Synchronization Test --- p.33 / Chapter 2.4.1 --- Experimental Results --- p.34 / Chapter 2.5 --- Gear Hobbing Test --- p.36 / Chapter 3 --- Diagnostic Tool: Gear Hobbing Simulation --- p.40 / Chapter 3.1 --- Simulation Model --- p.41 / Chapter 3.2 --- Simulations with Process Defects --- p.44 / Chapter 3.2.1 --- Asynchronous motion between tool and workpiece spindle --- p.44 / Chapter 3.2.2 --- Pitch error of the cutter hob --- p.45 / Chapter 3.2.3 --- Tool spindle run-out error --- p.47 / Chapter 3.2.4 --- Combination of process defects --- p.49 / Chapter 3.3 --- Experiment Validation --- p.50 / Chapter 4 --- Technical know-hows --- p.55 / Chapter 4.1 --- Premature Part Break-off --- p.55 / Chapter 4.2 --- Tool Alignment and Centering --- p.58 / Chapter 4.2.1 --- Two-turns Aligning Algorithm --- p.59 / Chapter 5 --- Conclusion and Future Work --- p.63 / References --- p.67 / Publication Record --- p.71 / Appendix --- p.72
18

Akustická analýza mechanických hodinek / Acoustical analysis of mechanical watsches

Dohnal, Marek January 2010 (has links)
This thesis is focused on the analysis of the characteristics of mechanical watches on the basis of their sound. There are theoretically analysed usual mechanical defects and disorders of watches and compensation of those defects. Particular attention is given to disorders, that can be extracted from the recorded acoustic sound of watches. There are also solved most appropriate methods of recording with a respect to the minimisation of ambient acoustic interference. The main part of this work is experimental measurement on watches and evaluation of achieved acoustic data. For this purpose, an autonomously running software were developed.
19

Assessing Tornado watches for Accuracy, Impacts on Daily Activities, and Potential Economic Impacts

Gutter, Barrett Frank 11 August 2017 (has links)
During 2007 – 2015, a total of 2,359 tornado watches were issued by the Storm Prediction Center and 10,840 tornadoes were confirmed. The objective of the first part of this study analyzed the accuracy of tornado watches for the nine-year period of 2007 – 2015. In addition to accuracy, fatalities, lead times, valid watch times, and areas were calculated for each tornado watch. 58.80% of the tornado watches had at least one tornado inside the tornado watch and 27.43% had at least one tornado outside the tornado watch. Of the 10,840 tornadoes, 56.70% were inside a tornado watch, 9.69% were outside a tornado watch, and 33.62% occurred when there was no tornado watch in effect. The average valid time for a tornado watch was 6 hours and 50 minutes and the average lead time for a tornado was 2 hours and 8 minutes. The second objective utilized a survey to determine participant knowledge and better understand “watch severity response”. A majority of the survey respondents accurately identified the difference between a tornado watch and a tornado warning. Most of the respondents described their weather knowledge as ‘moderately knowledgeable,’ ‘very knowledgeable,’ or ‘slightly knowledgeable.’ TV meteorologists, the NWS, and weather apps are the most common sources for daily weather information and information regarding a tornado watch. 81.63% of the respondents correctly identified if they were under a tornado watch during 2016. As the severity of the watch or the length of the activity increased, the likelihood of the respondent continuing the activity decreased. 38.87%, 54.76%, and 79.18% of the respondents ‘probably would not’ or ‘definitely would not’ continue an activity, lasting any duration, during a severe thunderstorm watch, a tornado watch, or a PDS tornado watch, respectively. The final objective attempts to categorize simple economic response to various watch severity types. The percent of respondents who would not continue an activity, based on the severity of the watch, was applied to a variety of watches that occurred during 2016. The economic loss associated with a watch ranged from $498,332.15 – $107,126,919.19.
20

Lasersvetsning : En undersökning av autenticitet och dess påverkan / Laser welding : A survey of authenticity and its impact

Fägerhall, Nils January 2016 (has links)
Med syftet att undersöka hur ett föremåls autenticitet påverkas av renovering/restaurering, har tolkningar av tre författares respektive syn på begreppet autenticitet applicerats på två restaurerade armbandsur. Renoverings- och restaureringsmetoden som har granskats är lasersvetsning, vilken är snabbt växande till följd av sina positiva egenskaper. Då armbandsurens ekonomiska värde stiger i takt med att det allmänna intresset blir större, finns relevans i att studera den renoverings- eller restaureringsmetod oftast diskuteras i samband med ekonomiskt värde. Även om författarnas ståndpunkter skiljer sig åt, så tycks en gemensam synpunkt vara att begreppet autenticitet är högst subjektivt. I förlängningen har det lett till slutsatsen att begreppet autenticitet ofta är individuellt och att det möjligtvis bör undvikas vid diskussion av konservering, restaurering och renovering. / With the aim to investigate how an object's authenticity is affected by the renovation/restoration, the interpretations of three authors respective views on the concept of authenticity is applied to two restored wristwatches. The renovation or restoration method that has been examined is laser welding, which is rapidly growing as a result of its positive qualities. Since wristwatches economic value rises in line with the public interest becomes greater, the study of the renovation or restoration method that is usually discussed in the context of economic value is relevant. Although the authors positions may differ, there seems to be a common denominator to the concept of authenticity as highly subjective. This has led to the conclusion that the concept of authenticity is often too individual and that it possibly should be avoided when discussing issues of preservation, restoration and renovation.

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