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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.
1

A rapid response multilevel differential modem for narrowband mobile fading channels

Castle, Robert John January 1993 (has links)
No description available.
2

Quantification and Evaluation of Physical Shoulder Exposures in Police Mobile Data Terminal Operators

McKinnon, Colin David January 2009 (has links)
Mobile police officers perform many of their daily duties within vehicles. Combined workspace inflexibility and prolonged driving exposure creates a risk for developing musculoskeletal issues. Limited research exists that quantitatively describes postural and load exposures associated with mobile police work. This study characterized officer activity during a typical workday and recommended a cruiser configuration that minimized musculoskeletal risk through laboratory quantification of physical loading during simulated police patrol tasks. A field study captured and analyzed digital video of traffic constables (N = 10) using custom Regional Enforcement Activity Characterization Tool (REACT) software. Mobile data terminal use represented over 13% of in-car activity time and was identified as a primary site for targeted design change. A laboratory study included 20 (10 male, 10 female) participants aged 18-35 with no recent history of right upper limb or low back disorder. Five mobile data terminal (MDT) locations and two driver seat designs were tested in two simulated police patrol testing sessions in a custom driving simulator. A self-selected mobile data terminal location reduced mean right shoulder elevation angle as well as perceived discomfort in both the low back and right shoulder relative to all other tested locations. Muscle activity was lowest at the self-selected location and current MDT location for all recorded muscles, with significant effects shown in posterior deltoid (p < .0001) and supraspinatus (p < .0001). Using a global ranking system, the self-selected location was identified as the best of all tested locations, followed by the current mobile data terminal location. The ALS driver seat effectively reduced discomfort (p < .0001) in the low back during a simulated police patrol session from 15.4mm in the Crown Victoria seat to 11.1mm on a VAS scale. Under these experimental conditions, a self-selected MDT and ALS driver seat reduced discomfort and physical loading compared to the current configuration.
3

Quantification and Evaluation of Physical Shoulder Exposures in Police Mobile Data Terminal Operators

McKinnon, Colin David January 2009 (has links)
Mobile police officers perform many of their daily duties within vehicles. Combined workspace inflexibility and prolonged driving exposure creates a risk for developing musculoskeletal issues. Limited research exists that quantitatively describes postural and load exposures associated with mobile police work. This study characterized officer activity during a typical workday and recommended a cruiser configuration that minimized musculoskeletal risk through laboratory quantification of physical loading during simulated police patrol tasks. A field study captured and analyzed digital video of traffic constables (N = 10) using custom Regional Enforcement Activity Characterization Tool (REACT) software. Mobile data terminal use represented over 13% of in-car activity time and was identified as a primary site for targeted design change. A laboratory study included 20 (10 male, 10 female) participants aged 18-35 with no recent history of right upper limb or low back disorder. Five mobile data terminal (MDT) locations and two driver seat designs were tested in two simulated police patrol testing sessions in a custom driving simulator. A self-selected mobile data terminal location reduced mean right shoulder elevation angle as well as perceived discomfort in both the low back and right shoulder relative to all other tested locations. Muscle activity was lowest at the self-selected location and current MDT location for all recorded muscles, with significant effects shown in posterior deltoid (p < .0001) and supraspinatus (p < .0001). Using a global ranking system, the self-selected location was identified as the best of all tested locations, followed by the current mobile data terminal location. The ALS driver seat effectively reduced discomfort (p < .0001) in the low back during a simulated police patrol session from 15.4mm in the Crown Victoria seat to 11.1mm on a VAS scale. Under these experimental conditions, a self-selected MDT and ALS driver seat reduced discomfort and physical loading compared to the current configuration.
4

A strategic business model for the introduction of Mobile Data Services in an emerging economy – focus on the South African market

Benn, Leon Jacobus 10 June 2005 (has links)
This dissertation investigates the critical success factors behind the successful introduction of Mobile Data Services to the South African market. An evaluation of the history of telecommunications found that progress in the global telecommunications industry has been characterised by innovation in technological hardware, followed by innovation in policies. Such innovation mainly contributed to the development of voice services in the mobile telecommunications industry. Wireless technology is no longer simply an extension of fixed line voice communication, but a mature independent technology. This maturity is also reflected by the declining state of revenues generated by voice services. Market incumbents expect data services to provide increased revenues. The current wireless industry business value chain is evolving and becoming more complex due to new incumbents in the market and new relationships that are formed between new and existing incumbents. Although a new structured value chain is presented, reality indicates a diffusion of functions within the value chain. The study has identified a number of the Critical Success Factors, which will be required to facilitate the introduction of Mobile Data Services to the South African market. Central to determining these Critical Success Factors is the design of a structured framework or model, which allows for this. The basic elements of this model are constructed from core concepts in the market, which became elevated during the literature study and industry survey. The model demonstrates the need to integrate the various components into a single coherent strategy, which is imperative for determining the Critical Success Factors. Copyright 2004, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Benn, LJ 2004, A strategic business model for the introduction of Mobile Data Services in an emerging economy – focus on the South African market, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-06102005-093913 / > / Dissertation (MSc (Technology Management))--University of Pretoria, 2006. / Graduate School of Technology Management (GSTM) / unrestricted
5

The design and engineering of innovative mobile data services : an ontological framework founded on business model thinking

Al-Debei, Mutaz M. January 2010 (has links)
This research investigates mobile service design and engineering in the mobile telecommunications industry. The mobile telecommunication business is shifting from one that was voice-centric to one that is almost all data-centric; thanks to recent rapid advances in Information and Communication Technologies (ICTs). The underlying reasons behind this shift can be traced back to two main issues that are interlinked. The first and major reason is that telecoms (telecommunication companies) are trying to generate new revenue streams based on data and information transmissions, given the saturation of the voice market. This is rational given the market opportunities in one direction and the pressures being generated by the current economic downturn from the other direction. The second reason relates to the flexibility of data, compared to voice. Indeed, the number of services that can be developed on the basis of data are much greater than those that can be developed on the basis of voice. However, the design and engineering of successful and innovative mobile data services has proven to be a complex undertaking. The number of effective mobile data services is relatively small and the revenue generated from such offerings has generally been below expectations. This research develops an ontological framework to help in changing this situation, and making mobile services engineering more effective and successful, following the design-science research paradigm. Design-science research, in general, aims to solve unstructured but relevant organizational or social problems through the development of novel and useful artefacts. As the current research aims to help in solving the mobile data services engineering dilemma by developing a purposeful ontological framework, the design-science research paradigm is deemed fitting. Within this paradigm, the author develops a novel design approach specified for ontology engineering, termed “OntoEng”. This design approach is used in this research for developing the ontological framework. The developed ontological framework is founded on business model thinking. The idea is that creating innovative mobile data services requires developing innovative business models. Indeed, innovative business models can help translate technological potential into economic value and allow telecoms to achieve their strategic objectives. The ontological framework includes the development of an ontology, termed “V4 Mobile Service BM Ontology” as well as “Mobile Key Value Drivers” for designing and engineering innovative mobile data services. The V4 Mobile Service BM Ontology incorporates four design dimensions: (1) value proposition including targeting; (2) value architecture including technological and organizational infrastructure; (3) value network dealing with aspects relating to partnerships and co-operations; and finally (4) value finance relating to costs, pricing, and revenue structures. Within these four dimensions, sixteen design concepts are identified along with their constituent elements. Relationships and interdependencies amongst the identified design constructs are established and clear semantics are produced. The research then derives six key value drivers for mobile service engineering as follows: (a) Market Alignment; (b) Cohesion; (c) Dynamicity; (d) Uniqueness; (e) Fitting Network-Mode; and (f) Explicitness. The developed ontological framework in this research is evaluated to ensure that it can be successfully implemented and performs correctly in the real world. The research mainly utilizes case analysis methods to ensure the semantic correctness of the ontological framework. Indeed, the developed ontological framework is employed as an analytical lens to examine the design and engineering of three key real-life cases in the mobile telecommunications industry. These cases are: (1) Apple’s iPhone Services and Applications; (2) NTT DoCoMo’s i-mode Services; and (3) Orange Business Services. For further validation, the developed ontological framework is evaluated against a set of criteria synthesized from ontology engineering and evaluation literature. These criteria are: Clarity; Coherence; Conciseness; Preciseness; Completeness; and Customizability. The developed ontological framework is argued to make significant contributions for theory, practice, and methodology. For theory, this research provides (1) a novel ontological framework for designing and engineering mobile data services; (2) a unified framework of the business model concept; and (3) a new design approach for ontology engineering in information systems. For practice, the current research provides practitioners in the telecommunications industry with systematic and customizable means to design, implement, analyze, evaluate, and change new and existing mobile data services to make them more manageable, effective, and creative. For methodology, the use of the design- science research paradigm for ontology engineering signifies the focal methodological contribution in this research given its novelty. This research also contributes to the understanding of the design-science research paradigm in information systems as it is relatively new. It provides a working example in which the author illustrates how recognizing design-science research as a paradigm is essential and useful to the research in information systems discipline.
6

Essays on the economics of information systems

Qiu, Liangfei 17 September 2014 (has links)
Information technology and social media have been a driving force in the economy and have transformed all aspects of business in recent decades. Understanding social networks is necessary to evaluate their impacts and examine key business issues involving information and technological innovations. The dissertation contains three chapters exploring those issues. In the first chapter, I propose an optimal procurement mechanism for mobile data offloading, covering both technological and business aspects. The unprecedented growth of cellular traffic driven by web surfing, video streaming, and cloud-based services is creating challenges for cellular service providers to fulfill the unmet demand. My present work contributes to the existing literature by developing an analytical model, which considers the unique challenge of integrating the longer range cellular resource and shorter range WiFi hotspots. In the second chapter, I examine the effect of a social network on prediction markets using a controlled laboratory experiment. In prediction markets, people place bets on events that they think are most likely to happen, thus revealing in a sense the nature of their private information. Through a randomized experiment, I show that when the cost of information acquisition is low, a social-network-embedded prediction market outperforms a non-networked prediction market. The third chapter studies different forms of social learning in the context of location-based networks: observational learning and the saliency effect. In recent years, the location-sensing mobile devices offer geographic location capabilities to share users' information about their locations with their friends. In our context, observational learning corresponds to the fact that "check-ins" made by friends help users learn the quality information of a venue; the saliency effect refers to that check-ins lead some of the uninformed consumers to discover a new venue. / text
7

Study of Users’ Data Volume as Function of Quality of Experience for Churn Prediction

Hemanth Kumar, Ravuri January 2016 (has links)
Customer churn has always been a problem to be addressed by the telecommunication service providers. So far, work done in this regard was based on analyzing historical data of the customers by using different data mining techniques. Investigations based on individual user behavior with a motive of churn prediction are expected to give an idea about the user’s point view towards churn. Data volumes/data usage of the users is seen as parameter to assess the satisfaction of the users with the service. The subjective and objective behavior of the mobile phone users has been captured by collecting data about the data volumes/data usage for both Wi-Fi and mobile services along with their ratings of Quality of Experience (QoE).   The Experience Sampling Method has been deployed to collect the user data. Android tool was used to collect weekly data volumes of the users. A questionnaire was prepared with questions regarding quality, annoyance and churn risk of the users. The questionnaire was used to collect the weekly opinions of the users on the service. A total of 22 users participated in the study, of which 3 persons churned to other service provider during the study. The data collected in the study was analyzed using averages, correlations and decision trees. Comparisons were made between Wi-Fi and mobile services, churners and non-churners/active users. A 2-fold churn prediction model was proposed based on conclusions of the study.
8

Use of multimedia services within ubiquitous environments : the role of place in the usage process of mobile data services

Papadopoulos, Homer January 2009 (has links)
Recently, there have been rapid developments in the fields of mobile and wireless technologies which have enabled the acquisition of information at anytime regardless of the location and mobility status of the users. However, despite the increasing popularity of mobile devices which are becoming an indispensable part of our everyday activities, the disappointing results regarding the adoption and use of mobile applications and data services lead scholars to question the understanding of the adoption and usage behaviour within these new wireless environments. The author believes that there could be attributes which are still unexplored and could provide an explanation why the mobile data services are still unsuccessful. The aim of this study is to explore, understand and highlight the role of place in the decision of the people to use mobile data services and thus to assist professionals and scholars to consider the importance of the attributes of place in the design of new applications and in the adoption and usage models of mobile technologies and services. In order to achieve this objective an exploratory in nature research was conducted combining conventional and innovative research methodologies. A model of place was generated which served as a sensitizing device in order to interpret, and analyse the collected data. The first phase of this research involved the understanding of the market in question and the selection of the appropriate case (mobile data services platform) to conduct the research. The second main phase of the research then sought to get a better understanding of how users experience place before deciding to use mobile data services. The research methods were applied within everyday settings with 30 users of the selected mobile data services platform, all of whom were selected according to specific criteria. The findings tend to suggest that participants did experience the different places in a similar way before deciding to use mobile data services.
9

Mining Mobile Group Patterns: A Trajectory-based Approach

Liu, Ying-Han 30 July 2004 (has links)
In recent years, with the popularization of the mobile devices, more and more location-based applications have been developed. As a result, location data of various objects is widely available. Identifying object groups that tend to move together is an emerging research topic. Existing approaches for identifying mobile group patterns assume the existence of raw location data which records a given object¡¦s position at every equal-spaced time point. However, a moving object may become disconnected voluntarily or involuntarily from time to time, and thus this assumption may not always valid. In this research, we describe the locations of moving object as a (non-continuous) trajectory function. Based on the new model, we re-define the mobile group mining problem and develop efficient algorithms for mining mobile groups. The proposed algorithms are evaluated via synthetic data generated by IBM City Simulator.
10

Design for Social Presence and Exploring Its Mediating Effect in Mobile Data Communication Services

Ogara, Solomon Omondi 05 1900 (has links)
The mobility, flexibility, convenience, and ubiquity of mobile data services (MDS) have contributed to their enormous growth and popularity with users. MDS allow users to communicate through mobile texting (mTexting), mobile Instant Messaging (mIM), multimedia messaging services (MMS), and email. A unique feature of MDS that enhances its popularity among its users is the awareness capability, which is revolutionizing the way MDS is being used to communicate today. It allows potential communication partners to socialize through these technologies. This dissertation explored the relationship between user experience, perceived richness, perceived social presence and satisfaction with MDS. A research model for examining the antecedent conditions that influence social presence, richness, social interaction and satisfaction with MDS was developed. Partial least square analysis showed that user experience influenced both social presence and richness. Also supported was the relationship between richness, social presence and satisfaction with MDS. Social presence mediated the relationship between user experience and richness. However, only one dimension of interactivity influenced social presence.

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