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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

Internal problems of changing customer service systems

Trncic, Fazileta, Daher, Mariam, Nacional, Vanessa January 2016 (has links)
This thesis focuses on the internal problems for companies changing customer service system and how to best avoid these problems and make the implementation of the new system as efficient as possible. The reason for focusing on the customer service systems was since more and more companies are transcending to e-commerce and having some form of customer service is common. As the technology is changing so does the requirements for the system and thereby companies are in need for constant change. The problem area is wide and the results can be applied to almost any company undergoing changes of customer service systems. In order to find the internal problems and how to avoid these to efficiently implement the new system, interviews were carried out with companies that had undergone some form of change in their customer service. Theoretical studies were also carried out in order to confirm the interviews. The results of the study were that companies need to involve the affected employees and work with employee involvement. Doing otherwise would in many cases make the employees resistant to change. Furthermore, the IT changes being carried out need to have a more humanistic perspective rather than technological perspective, as the case was. The main finding was that there was a clear connection between the level of employee involvement and the level of efficiency when changing to a new system. In addition, educating employees on the new system and information sharing about the system already before start would create efficient implementation.
2

Managing terminals mobility for personal communication systems.

January 1996 (has links)
by Lee Ying Kit. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 79-[83]). / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Overview of Personal Communication Systems --- p.1 / Chapter 1.2 --- Design issues on PCS --- p.2 / Chapter 1.2.1 --- Channel allocation --- p.2 / Chapter 1.2.2 --- Multiple Access --- p.3 / Chapter 1.2.3 --- Handoffs --- p.4 / Chapter 1.2.4 --- Location management --- p.6 / Chapter 1.3 --- Motivation of this thesis --- p.9 / Chapter 1.4 --- The theme of this thesis --- p.10 / Chapter 1.4.1 --- Methodology --- p.10 / Chapter 1.4.2 --- The system model and assumptions --- p.12 / Chapter 1.4.3 --- Outline of the thesis --- p.13 / Chapter 2 --- Overview of the traditional location update schemes --- p.15 / Chapter 2.1 --- Why do we need location registration? --- p.15 / Chapter 2.2 --- Location registration by Geographic and Time based methods --- p.16 / Chapter 2.2.1 --- Geographic Based Registration Schemes --- p.16 / Chapter 2.2.2 --- Time Based Registration Scheme --- p.20 / Chapter 2.3 --- Peformance Analysis of protocols --- p.20 / Chapter 2.3.1 --- Analytical Results --- p.22 / Chapter 2.3.2 --- A Numerical Study --- p.23 / Chapter 2.4 --- Summary of the results for time and geographic based location update protocol --- p.24 / Chapter 3 --- The Implementation of Bloom filter on location registration --- p.27 / Chapter 3.1 --- Introduction --- p.27 / Chapter 3.2 --- The Implementation of Bloom filter on location registration --- p.29 / Chapter 3.2.1 --- Location Update by Bloom filter --- p.29 / Chapter 3.2.2 --- Paging algorithm --- p.29 / Chapter 3.2.3 --- An example --- p.30 / Chapter 3.3 --- Performance evaluation of the Bloom filter based location update scheme --- p.32 / Chapter 3.4 --- Summary of the results for Bloom filter based scheme --- p.35 / Chapter 4 --- One-Bit-Reply protocol --- p.36 / Chapter 4.1 --- Introduction --- p.36 / Chapter 4.2 --- One-Bit-Reply protocol --- p.37 / Chapter 4.2.1 --- Grouping of MU's --- p.38 / Chapter 4.2.2 --- The Update Procedure --- p.39 / Chapter 4.2.3 --- Paging algorithm --- p.40 / Chapter 4.3 --- Performance evaluation of the OBR protocol --- p.42 / Chapter 4.3.1 --- Analytical Results --- p.42 / Chapter 4.3.2 --- A Simulation Study --- p.43 / Chapter 4.4 --- Comparison of the location registration schemes - A numerical study --- p.45 / Chapter 4.5 --- Summary --- p.46 / Chapter 5 --- A case study - Implementing the OBR protocol on GSM sytems --- p.49 / Chapter 5.1 --- Introduction --- p.49 / Chapter 5.2 --- The Architecture of Global System for Mobile Communicaitons (GSM) --- p.50 / Chapter 5.3 --- Location Update Procedure of GSM --- p.51 / Chapter 5.4 --- Implementing OBR protocol on GSM --- p.52 / Chapter 5.5 --- Influence of the OBR on the VLR's and HLR --- p.55 / Chapter 5.5.1 --- Analysis of traditional method --- p.57 / Chapter 5.5.2 --- Analysis of OBR --- p.58 / Chapter 5.6 --- Summary --- p.59 / Chapter 6 --- Conclusion --- p.61 / Chapter 6.1 --- Summaries of Results --- p.61 / Chapter 6.1.1 --- Cost functions --- p.61 / Chapter 6.1.2 --- Optimization of the cost functions --- p.62 / Chapter 6.1.3 --- Implementation of OBR into GSM --- p.64 / Chapter 6.2 --- Suggestions for further researches --- p.64 / Appendix --- p.65 / Chapter A --- Derivation of cost functions --- p.66 / Chapter A.1 --- Geographic based scheme --- p.66 / Chapter A.2 --- Time based scheme --- p.67 / Chapter A.3 --- Bloom filter based scheme --- p.68 / Chapter B --- On the optimality of the cost functions --- p.71 / Chapter B.1 --- Steepest Descent Algorithm for various protocols --- p.71 / Chapter B.2 --- Bloom filter based scheme --- p.72 / Chapter B.3 --- Time Based Scheme --- p.74 / Chapter B.4 --- One-Bit-Reply scheme --- p.75 / Chapter B.5 --- Geographic Based Scheme --- p.75 / Chapter C --- Simulation of OBR --- p.77 / Bibliography --- p.79
3

Downlink resource allocation for orthogonal frequency division multiple access systems.

Chee, Kit-Ming Tommy January 2007 (has links)
Wireless spectral efficiency is increasingly important due to the rapid growth of demand for high data rate wideband wireless services. The design of a multi-carrier system,such as an orthogonal frequency division multiple access (OFDMA) system, enables high system capacity suited for these wideband wireless services. This system capacity can be further optimised with a resource allocation scheme by exploiting the characteristics of the wireless fading channels. The fundamental idea of a resource allocation scheme is to efficiently distribute the available wireless resources, such as the sub-carriers and transmission power, among all admitted users in the system. In this thesis, we present the findings of the investigation into the impact of several resource allocation schemes in an OFDMA environment. We show that in an OFDMA environment without the consideration of sub-carrier assignment, the sub-optimal power allocation closed-form solution can be derived via a constrained optimisation with the duality theorem. With a perfect feedback of channel condition, the proposed low-complexity algorithm that utilises the closed-form solution can maximise the sum capacity to approach near-optimal capacity. We derive the sub-optimal sub-carrier and power allocation closed-form solution via a similar constrained optimisation process. With an imperfect or outdated feedback of channel condition, the adaptive sub-carrier and power allocation scheme not only fails to improve but also further deteriorates the system throughput. We present and discuss the formation of the finite-state Markov channel. We show that by using the dynamics of the Markov channel, the channel quality can be reliably predicted in advance. We analyse via simulation the spectral efficiency achieved by this channel prediction scheme on an OFDMA system. We address the importance of fairness in resource allocation from a game-theoretic perspective. With different utility and preference functions that best describe the gain in users’ throughput as more sub-carriers are allocated to the individual user, we formulate the resource allocation problem into cooperative and non-cooperative games. We study via simulation the effectiveness and fairness of the cooperative and non-cooperative resource allocation schemes on an OFDMA system. Finally, we draw conclusions on our research work and outline the future research topics in connection with our current studies. / Thesis(PhD) -- School of Electrical and Electronic Engineering, 2007
4

Scalable analysis and design of service systems

Zhang, Bo 29 March 2011 (has links)
In this dissertation, we develop analytical and computational tools for performance analysis and design of large-scale service systems. The dissertation consists of three main chapters. The first chapter is devoted to devising efficient task assignment policies for large-scale service system models from a rare event analysis standpoint. Specifically, we study the steady-state behavior of multi-server queues with general job size distributions under size-interval task assignment (SITA) policies. Assuming Poisson arrivals and the existence of the alpha-th moment of the job size distribution for some alpha> 1, we show that if the job arrival rate and the number of servers increase to infinity with the traffic intensity held fixed, a SITA policy parameterized by alpha minimizes in a large deviation sense the steady-state probability that the total number of jobs in the system is greater than or equal to the number of servers. The optimal large deviation decay rate can be arbitrarily close to the one for the corresponding probability in an infinite-server queue, which only depends on the system traffic intensity but not on any higher moments of the job size distribution. This supports in a many-server asymptotic framework the common wisdom that separating large jobs from small jobs protects system performance against job size variability. In the second chapter, we study constraint satisfaction problems for a Markovian parallel-server queueing model with impatient customers, motivated by large telephone call centers. To minimize the staffing level subject to different service-level constraints, we propose refined square-root staffing (SRS) rules, which preserve the insightfulness and computational scalability of the celebrated SRS principle and yet achieve a stronger form of optimality. In particular, using asymptotic series expansion techniques, we first develop refinements to a set of asymptotic performance approximations recently used in analyzing large call centers, namely, the Quality and Efficiency Driven (QED) diffusion approximations. We then use the improved performance approximations to explicitly characterize the error of conventional SRS and further obtain the refined SRS rules. Finally, we demonstrate how the explicit form of the staffing refinements enables an analytical assessment of the accuracy of conventional SRS and its underlying QED approximation. In the third chapter, we study a fluid model for many-server Markovian queues in changing environments, which can be used to model large-scale service systems with customer abandonments and time-varying arrivals. We obtain the stationary distribution of the fluid model, which refines and is shown to converge, as the environment changing rate vanishes in a proper way, to a simple discrete bimodal approximation. We also prove that the fluid model arises as a law of large number limit in a many-server asymptotic regime.
5

Development of a framework for obsolescence resolution cost estimation

Romero Rojo, Francisco Javier January 2011 (has links)
Currently, manufacturing organisations worldwide are shifting their business models towards Product-Service Systems (PSS), which implies the development of new support agreements such as availability-based contracts. This transition is shifting the responsibilities for managing and resolving obsolescence issues from the customer to the prime contractor and industry work share partners. This new scenario has triggered a new need to estimate the Non-Recurring Engineering (NRE) cost of resolving obsolescence issues at the bidding stage, so it can be included in the support contract. Hence, the aim of this research is to develop an understanding about all types of obsolescence and develop methodologies for the estimation of NRE costs of hardware (electronic, electrical and electromechanical (EEE) components and materials) obsolescence that can be used at the bidding stage for support contracts in the defence and aerospace sectors. For the accomplishment of this aim, an extensive literature review of the related themes to the research area was carried out. It was found that there is a lack of methodologies for the cost estimation of obsolescence, and also a lack of understanding on the different types of obsolescence such as materials and software obsolescence. A systematic industrial investigation corroborated these findings and revealed the current practice in the UK defence sector for cost estimation at the bidding stage, obsolescence management and obsolescence cost estimation. It facilitated the development of an understanding about obsolescence in hardware and software. Further collaboration with experts from more than 14 organisations enabled the iterative development of the EEEFORCE and M-FORCE frameworks, which can be used at the bidding stage of support contracts to estimate the NRE costs incurred during the contracted period in resolving obsolescence issues in EEE components and materials, respectively. These frameworks were implemented within a prototype software platform that was applied to 13 case studies for expert validation.
6

Mobility management for personal communications networks

Ho, Joseph S. M 05 1900 (has links)
No description available.
7

Downlink resource allocation for orthogonal frequency division multiple access systems

Chee, Kit-Ming Tommy. January 2007 (has links)
Thesis (Ph.D.) -- University of Adelaide, School of Electrical and Electronic Engineering, 2007. / "April 2007" Bibliography: pages 127-138. Also available in print form.
8

End-to-end security for mobile devices/

Kayayurt, Barış. Tuğlular, Tuğkan January 2004 (has links) (PDF)
Thesis (Master)--İzmir Institute of Technology, İzmir, 2004. / Includes bibliographical references (leaves. 120).
9

A methodology and software platform for building wearable communities /

Kortuem, Gerd. January 2002 (has links)
Thesis (Ph. D.)--University of Oregon, 2002. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 242-256). Also available for download via the World Wide Web; free to University of Oregon users.
10

The analysis of the diffusion of personal tele-communications in South Africa

Malebo, Limpho Mercy 09 June 2006 (has links)
Please read the abstract in the section 00front of this document / Dissertation (MSc (Technology Management))--University of Pretoria, 2007. / Graduate School of Technology Management (GSTM) / unrestricted

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