To make storage management transparent to users, enterprises rely on expensive storage infrastructure, such as high end storage appliances, tape robots, and offsite storage facilities, maintained by full-time professional system administrators. From the user's perspective access to data is seamless regardless of location, backup requires no periodic, manual action by the user, and help is available to recover from storage problems. The equipment and administrators protect users from the loss of data due to failures, such as device crashes, user errors, or virii, as well as being inconvenienced by the unavailability of critical files. Home users and small businesses must manage increasing amounts of important data distributed among an increasing number of storage devices. At the same time, expert system administration and specialized backup hardware are rarely available in these environments, due to their high cost. Users must make do with error-prone, manual, and time-consuming ad hoc solutions, such as periodically copying data to an external hard drive. Non-technical users are likely to make mistakes, which could result in the loss of a critical piece of data, such as a tax return, customer database, or an irreplaceable digital photograph. In this thesis, we show how to provide transparent storage management for home and small business users We introduce two new systems: The first, PodBase, transparently ensures availability and durability for mobile, personal devices that are mostly disconnected. The second, SLStore, provides enterprise-level data safety (e.g. protection from user error, software faults, or virus infection) without requiring expert administration or expensive hardware. Experimental results show that both systems are feasible, perform well, require minimal user attention, and do not depend on expert administration during disaster-free operation. PodBase relieves home users of many of the burdens of managing data on their personal devices. In the home environment, users typically have a large number of personal devices, many of them mobile devices, each of which contain storage, and which connect to each other intermittently. Each of these devices contain data that must be made durable, and available on other storage devices. Ensuring durability and availability is difficult and tiresome for non-expert users, as they must keep track of what data is stored on which devices. PodBase transparently ensures the durability of data despite the loss or failure of a subset of devices; at the same time, PodBase aims to make data available on all the devices appropriate for a given data type. PodBase takes advantage of storage resources and network bandwidth between devices that typically goes unused. The system uses an adaptive replication algorithm, which makes replication transparent to the user, even when complex replication strategies are necessary. Results from a prototype deployment in a small community of users show that PodBase can ensure the durability and availability of data stored on personal devices under a wide range of conditions with minimal user attention. Our second system, SLStore, brings enterprise-level data protection to home office and small business computing. It ensures that data can be recovered despite incidents like accidental data deletion, data corruption resulting from software errors or security breaches, or even catastrophic storage failure. However, unlike enterprise solutions, SLStore does riot require professional system administrators, expensive backup hard- ware, or routine, manual actions on the part of the user. The system relies on storage leases, which ensure that data cannot be overwritten for a pre-determined period, and an adaptive storage management layer which automatically adapts the level of backup to the storage available. We show that this system is both practical, reliable and easy to manage, even in the presence of hardware and software faults.

Este trabalho tem por objetivo propor alguns critérios básicos, para o desenvolvimento de plásticos de engenharia em aplicações, componentes e partes dos veículos chamados populares, particularmente no Brasil, em substituição a partes tradicionalmente usinadas, fundidas ou injetadas em ligas metálicas. A despeito da desconfiança que cerca alguns dos componentes em plásticos que se destinam às aplicações automotivas, (e uma das principais razões para isso, são as elevadas temperaturas presentes em algumas áreas do automóvel), as grandes indústrias do setor não deixam de conceber novos projetos em polímeros de alta performance, para aplicações tidas como críticas em termos de resistência geral. Os chamados plásticos de engenharia são preferivelmente escolhidos devido à sua fácil processabilidade, e sua flexibilidade em propiciar desenhos mais complexos, com boa estabilidade dimensional e uma excelente resistência à corrosão em ambientes de hostilidade química. No passado, as empresas claramente optavam pelos plásticos chamados de termofixos, que hoje estão quase esquecidos ou obsoletos (principalmente devido aos processamentos mais custosos e/ou mais lentos). Hoje são largamente substituídos pelos termoplásticos de engenharia. Atualmente, o consumo de plásticos em alguns carros brasileiros já alcança quase 130 kg de plásticos nos seus interiores e/ou exteriores (como o Ford KA, por exemplo), o que ajuda a reduzir o peso total do automóvel, aumentando a economia de combustível, reduzindo os custos de processos, aliada a uma excelente aparência superficial. Este trabalho versará sobre a possibilidade de se propor critérios mais objetivos na fase inicial de um processo de seleção de plásticos de engenharia (notadamente, poliamidas, acetais, poliésteres, e policarbonato), aumentando a eficácia da escolha e diminuindo custos (evitando erros e economizando tempo), como um guia prático de consulta para engenheiros e profissionais do setor automotivo brasileiro. / The main objective of this paper is to propose some basic economical and objective criteria for the engineering plastics development in applications, components and parts in the low-end cars segment (known in Brazil as popular cars), to replace traditional metallic machined, die-casted or injected parts. In spite of the lack of reliance in plastics components in automotive applications (one of them being the high temperature in the engine area), big industries in the sector always conceive new projects on high performance polymers for applications considered critical because of its general resistance. The named engineering plastics are preferably chosen due to its easy processing, complex design flexibility, with a good dimensional stability and an excellent resistance against corrosion in environments with chemical hostility. In the past, companies clearly selected the called thermo-stable plastics, almost forgotten or obsolete nowadays (mainly due to the high cost and/or slowness on processing). Today they are largely replaced by engineering thermoplastics. Nowadays, the consumption of plastics in Brazilian low-end cars already reached approximately 130 kg of plastics in their interior and/or exterior (like in Ford KA, for example), which helps to reduce total car weight, increasing the saving of fuel, mitigating process costs, besides to an excellent surface appearance. This paper will approach about the possibility of proposing more objective criteria in the initial phase of the engineering plastics selection (notably polyamides, acetals, polyesters, and polycarbonates), increasing the choice efficacy and diminishing costs (avoiding mistakes and saving time), as a practical consulting guide to engineers and professionals from the Brazilian automotive sector.

Företag använder marknadssegmentering för att dela in kunder i grupper utefter liknande karaktäristika, som exempelvis betalningsvilja. Företag kan i sinom tid möta en mättad marknad inom dess segment, och behöver då ompositionera strategier mot nya segment för fortsatt kundtillväxt. För företag som valt en positionering mot segment med hög betalningsvilja (high-end), är en möjlighet för fortsatt kundtillväxt istället ompositionering mot lägre segment (low-end). Syftet med studien var att kartlägga och identifiera hur företag besittande en högpristjänst, kan nå kunder med lägre betalningsvilja genom nedåtgående segmentering. Detta utan att skada varumärket och riskera förluster av befintliga kunder. Utifrån syftet fastslogs följande frågeställning: • Hur kan SaaS-företag som besitter en high-end tjänst, använda nedåtgående segmentering utan att skada varumärket och förlora befintliga kunder? Studiens avgränsning begränsades till SaaS-företag, en delbransch inom IT-branschen. Detta med anledning av dess unika, relativt obefintliga, marginalkostnad. Studien har genomförts genom att använda en kvalitativ forskningsmetodik, i form av fem semistrukturerade intervjuer med fyra företag ståendes inför det problem som berörs. Studien består genomgående av en struktur baserad på blocken segmentering, tillväxt, lönsamhet samt varumärke. Studiens resultat, baserad på insamlad empiri och analys, har lett till en slutsats som påvisat fyra stycken beståndsdelar. Dessa ter sig vara faktorer som en high-end tjänst bör inneha, för en lyckad strategiförändring mot lägre marknadssegment. Dessa fyra kriterier är marknadsmedvetenhet, skalbar tjänst, flerstegig prismodell samt varumärkesmedvetenhet. / Companies use market segmentation to divide customers into groups along similar characteristics, such as willingness to pay. Companies could eventually meet a saturated market within its segments, and would then need to reposition towards new segments for continued customer growth. For companies that choose to position themselves against segments with high willingness to pay (high-end), a possibility of continued customer growth is to position segments with lower willingness to pay (low- end). The purpose of this thesis was to plot and identify how companies, proprietors of a high-end solution, can use downward segmentation to reach customers with lower willingness to pay. This without damaging the brand and risking losses of existing customers. Based on the purpose of the thesis, the following research question has been established: • How can SaaS-companies that have a high-end service, use downward segmentation without damaging their brand and losing existing customers? The delimitation of the study was limited to SaaS companies, a sub-sector in the IT industry. This is due to its unique, relatively non-existent, marginal cost. The study has been conducted using a qualitative research method, in the form of five semi structured interviews with four companies facing the problem concerned. The study is continuously conducted through a structure based on segmentation, growth, profitability and brand. The results of the study, based on collected empirical data and the analysis, have led to a conclusion containing four specific components. These appear to be factors that a high-end service should hold for a successful strategy change towards lower market segments. These four criteria are market awareness, scalable service, multi-pricing model and brand awareness. This thesis is written in Swedish.

Este trabalho tem por objetivo propor alguns critérios básicos, para o desenvolvimento de plásticos de engenharia em aplicações, componentes e partes dos veículos chamados populares, particularmente no Brasil, em substituição a partes tradicionalmente usinadas, fundidas ou injetadas em ligas metálicas. A despeito da desconfiança que cerca alguns dos componentes em plásticos que se destinam às aplicações automotivas, (e uma das principais razões para isso, são as elevadas temperaturas presentes em algumas áreas do automóvel), as grandes indústrias do setor não deixam de conceber novos projetos em polímeros de alta performance, para aplicações tidas como críticas em termos de resistência geral. Os chamados plásticos de engenharia são preferivelmente escolhidos devido à sua fácil processabilidade, e sua flexibilidade em propiciar desenhos mais complexos, com boa estabilidade dimensional e uma excelente resistência à corrosão em ambientes de hostilidade química. No passado, as empresas claramente optavam pelos plásticos chamados de termofixos, que hoje estão quase esquecidos ou obsoletos (principalmente devido aos processamentos mais custosos e/ou mais lentos). Hoje são largamente substituídos pelos termoplásticos de engenharia. Atualmente, o consumo de plásticos em alguns carros brasileiros já alcança quase 130 kg de plásticos nos seus interiores e/ou exteriores (como o Ford KA, por exemplo), o que ajuda a reduzir o peso total do automóvel, aumentando a economia de combustível, reduzindo os custos de processos, aliada a uma excelente aparência superficial. Este trabalho versará sobre a possibilidade de se propor critérios mais objetivos na fase inicial de um processo de seleção de plásticos de engenharia (notadamente, poliamidas, acetais, poliésteres, e policarbonato), aumentando a eficácia da escolha e diminuindo custos (evitando erros e economizando tempo), como um guia prático de consulta para engenheiros e profissionais do setor automotivo brasileiro. / The main objective of this paper is to propose some basic economical and objective criteria for the engineering plastics development in applications, components and parts in the low-end cars segment (known in Brazil as popular cars), to replace traditional metallic machined, die-casted or injected parts. In spite of the lack of reliance in plastics components in automotive applications (one of them being the high temperature in the engine area), big industries in the sector always conceive new projects on high performance polymers for applications considered critical because of its general resistance. The named engineering plastics are preferably chosen due to its easy processing, complex design flexibility, with a good dimensional stability and an excellent resistance against corrosion in environments with chemical hostility. In the past, companies clearly selected the called thermo-stable plastics, almost forgotten or obsolete nowadays (mainly due to the high cost and/or slowness on processing). Today they are largely replaced by engineering thermoplastics. Nowadays, the consumption of plastics in Brazilian low-end cars already reached approximately 130 kg of plastics in their interior and/or exterior (like in Ford KA, for example), which helps to reduce total car weight, increasing the saving of fuel, mitigating process costs, besides to an excellent surface appearance. This paper will approach about the possibility of proposing more objective criteria in the initial phase of the engineering plastics selection (notably polyamides, acetals, polyesters, and polycarbonates), increasing the choice efficacy and diminishing costs (avoiding mistakes and saving time), as a practical consulting guide to engineers and professionals from the Brazilian automotive sector.

Desde o plano real, em 1994, com a estabilização da moeda e maior facilidade ao crédito, verifica-se o aumento do consumo da população de baixa renda em vários setores do mercado. Além do preço mais baixo, fator indispensável para atender a essa camada da população, discute-se quais são e como são planejadas as estratégias de marketing e comunicação utilizadas pelas empresas que atuam no mercado popular. Nesse contexto, esta pesquisa tem como objetivo geral desenvolver modelos de análise integrada para a definição de estratégias de marketing e comunicação de produtos eletroeletrônicos populares. Para alcançar o objetivo proposto, o estudo utilizou o método exploratório por meio dos seguintes procedimentos: pesquisa bibliográfica em livros, dissertações, teses, revistas, jornais, sites e pesquisa empírica, que foi conduzida em duas fases combinando as abordagens qualitativa (primeira fase) e quantitativa (segunda fase). A população estudada foi composta por executivos das áreas de marketing e comunicação de empresas do setor eletroeletrônico associadas à ELETROS (Associação Nacional dos Fabricantes de Produtos Eletroeletrônicos). O subsídio teórico da análise da pesquisa consistiu na definição de produto popular e população de baixa renda; na análise do consumidor de baixa renda; no estudo das estratégias de marketing e comunicação; no tema da construção de marca; na abordagem dos modelos de análise BCG, GE e SWOT; por fim, na análise das diversas configurações de negócio que poderiam ser adotadas pelas empresas pesquisadas. Os resultados mostraram que as empresas estudadas utilizam principalmente a análise SWOT e as pesquisas de mercado para elaborar a sua estratégia de marketing e comunicação. Porém esse planejamento não é específico para produtos populares. De forma geral, ele se concentra no produto, e, em segundo lugar, com a mesma relevância, em preço e análise do mercado. A partir disso, foram elaborados modelos de análise integrada para a definição de estratégias de marketing e comunicação de produtos eletroeletrônicos populares. / Since the Real Plan was introduced in 1994, bringing with it a stable currency and easier credit, there has been a noted increase in spending among members of the lower-income population in various market sectors. In addition to lower prices, an indispensable factor when targeting this section of the population, there is discussion of marketing and communication strategies used by companies operating in the lowend market and how they plan such strategies. Within this context, the overall objective of this study is to develop integrated analysis models for defining marketing and communication strategies for low-end household appliances and electronics. An exploratory approach was taken in this study, comprising a study of the literature (books, dissertations, theses, magazines, newspapers, and websites) and two phases of empirical research: first qualitative, then quantitative. The study group comprised marketing and communications executives at companies affiliated with Eletros (National Association of Appliance and Electronic Product Manufacturers). The theoretical component of the study involved defining low-end products and the low-income population, and analysing low-income consumers, marketing and communication strategies, brand building, the use of BCG, GE and SWOT analyses, and different business models that could be adopted by the companies studied. Results showed that companies mostly used SWOT analyses and market surveys when planning marketing and communication strategies. However, this planning isnt specific for low-end products. In general, they concentrate on the product, and in second place (with the same relevance), on price and market analyses. Based on these findings, integrated analysis methods were designed for use when planning marketing and communication strategies for low-end household appliances and electronics.

Desde o plano real, em 1994, com a estabilização da moeda e maior facilidade ao crédito, verifica-se o aumento do consumo da população de baixa renda em vários setores do mercado. Além do preço mais baixo, fator indispensável para atender a essa camada da população, discute-se quais são e como são planejadas as estratégias de marketing e comunicação utilizadas pelas empresas que atuam no mercado popular. Nesse contexto, esta pesquisa tem como objetivo geral desenvolver modelos de análise integrada para a definição de estratégias de marketing e comunicação de produtos eletroeletrônicos populares. Para alcançar o objetivo proposto, o estudo utilizou o método exploratório por meio dos seguintes procedimentos: pesquisa bibliográfica em livros, dissertações, teses, revistas, jornais, sites e pesquisa empírica, que foi conduzida em duas fases combinando as abordagens qualitativa (primeira fase) e quantitativa (segunda fase). A população estudada foi composta por executivos das áreas de marketing e comunicação de empresas do setor eletroeletrônico associadas à ELETROS (Associação Nacional dos Fabricantes de Produtos Eletroeletrônicos). O subsídio teórico da análise da pesquisa consistiu na definição de produto popular e população de baixa renda; na análise do consumidor de baixa renda; no estudo das estratégias de marketing e comunicação; no tema da construção de marca; na abordagem dos modelos de análise BCG, GE e SWOT; por fim, na análise das diversas configurações de negócio que poderiam ser adotadas pelas empresas pesquisadas. Os resultados mostraram que as empresas estudadas utilizam principalmente a análise SWOT e as pesquisas de mercado para elaborar a sua estratégia de marketing e comunicação. Porém esse planejamento não é específico para produtos populares. De forma geral, ele se concentra no produto, e, em segundo lugar, com a mesma relevância, em preço e análise do mercado. A partir disso, foram elaborados modelos de análise integrada para a definição de estratégias de marketing e comunicação de produtos eletroeletrônicos populares. / Since the Real Plan was introduced in 1994, bringing with it a stable currency and easier credit, there has been a noted increase in spending among members of the lower-income population in various market sectors. In addition to lower prices, an indispensable factor when targeting this section of the population, there is discussion of marketing and communication strategies used by companies operating in the lowend market and how they plan such strategies. Within this context, the overall objective of this study is to develop integrated analysis models for defining marketing and communication strategies for low-end household appliances and electronics. An exploratory approach was taken in this study, comprising a study of the literature (books, dissertations, theses, magazines, newspapers, and websites) and two phases of empirical research: first qualitative, then quantitative. The study group comprised marketing and communications executives at companies affiliated with Eletros (National Association of Appliance and Electronic Product Manufacturers). The theoretical component of the study involved defining low-end products and the low-income population, and analysing low-income consumers, marketing and communication strategies, brand building, the use of BCG, GE and SWOT analyses, and different business models that could be adopted by the companies studied. Results showed that companies mostly used SWOT analyses and market surveys when planning marketing and communication strategies. However, this planning isnt specific for low-end products. In general, they concentrate on the product, and in second place (with the same relevance), on price and market analyses. Based on these findings, integrated analysis methods were designed for use when planning marketing and communication strategies for low-end household appliances and electronics.

本研究主要探討電源供應器產業之突破式創新的可能性。透過文獻了解創新的涵意和學者對創新的分類，深入比較「維持性創新」（Sustaining Innovation）與其高階入侵（High-end encroachment），以及「突破式創新」（Disruptive Innovation）之三種低階入侵（Low-end encroachment）方式，分別為：即刻市場入侵（Immediate low-end encroachment）、邊緣市場入侵（Fringe-market low-end encroachment）、分離市場入侵（ Detached-market low-end encroachment）。 首先探究電源供應器之技術、產業現況、供應鏈結構及電源供應器的應用分類；將無線充電器歸類為新科技，針對無線充電技術的市場、聯盟、應用、未來機會做深入的剖析。為驗證無線充電技術之突破式創新的可能性分析，本研究採取學者Schmidt（2008）所提之「辨別創新的三步驟」進行突破性創新的驗證，以「無線方便性」與「充電速度」為關鍵指標。現有充電器的消費者比較重視「充電速度」，而新市場的消費者比較在意「無線方便性」，兩者的需求曲線不同，無線充電科技因提供與既有市場不同的新功能，所以被歸類為「低端突破式創新」之「分離市場」入侵。分離市場的消費者願意為無線的方便性付出較高的價格購買新產品。在新產品推出初期不會侵蝕主流市場的銷售，但經過一段時間，當價格下降及充電速度性能提升後，新產品會「低端突破」原有市場；到最後，新產品會往主流市場及高階市場擴散而影響既有產業和原來的市場結構。 本文藉由與產業專家的深入訪談得知目前既有企業對於新科技尚未開始準備，著實也驗證了Christensen（2005）提過主流企業常常因為過度著重現有技術，而忽略突破性科技的存在。最後，本文建議既有電源供應器產業應多留意突破性科技的入侵且適時跨入新科技，才能在突破性科技崛起時做好準備。 / The main purpose of this research is to examine the potential of disruptive innovation on the power supply industry. This article investigates the definitions and the classifications of innovation by various scholars. It identifies sustaining innovation with its high-end encroachment and disruptive innovation with its three approaches of low-end encroachment which are immediate, fringe-market, and detached-market. This article reviews the power supply industry and its technology, applications, market status, supply chains and then investigates the wireless charging industry and its technologies, evolutions, standards, and market opportunities. To identify the potential of wireless charging becoming disruptive technology, the article refers to the three-step framework of Schmidt (2008) to assess the potential diffusion pattern. The primary attribute of the incumbent is the charging time whereas the primary attribute of new technology is its wireless convenience. The results classify wireless charging as a low-end detached-market encroachment. The current and new products initially sell to the two opposite ends of the market and the highest willingness to pay for each market in the beginning are different, which are “detached “from one another. Over time, charging time would be expected to improve and cost would be expected to decrease, wireless chargers will be more favorable to high-end users of the wired chargers, and eventually current market will be encroached by the new technology. The interviews with incumbents present that current power supply firms have not initiated the development of wireless technology. Companies usually pursue sustaining innovations at the higher tiers of their markets because this is what has historically helped them succeed and they often missed the chances to disruptive innovation. (Christensen, 2005) The results suggest the established organizations to take more efforts to start looking into the disruptive technology so that established organizations will not be displaced by the new firms.

全球行動電話用戶數於2002年達到12億，首度超過固定電話用戶數之11億；行動電話用戶數並於2008年達41億，為固定電話用戶數(13億)之3倍以上。行動電話相對於固定電話之主要優勢在於系統之建置成本低及佈建速度快；行動電話之快速普及已成為創新擴散研究之重要題材。 行動電話擴散之研究為選取一成長模型(例如Gompertz、Logistic或Bass模型)並類比該模型以求出擴散之參數(例如成長速率)，以進一步(1)了解相關驅動因子(例如技術創新、市場開放等)對擴散參數之影響，及(2)延伸擴散模型曲線以預測未來之成長。 惟成長模型之選取尚無原理原則可供遵循而具隨機性(ad hoc basis)。為找出模型選用之可能規律，以降低模型選用之隨機性並提高成長預測之準確度，本研究以十二個代表性國家(巴、中、法、德、印、日、韓、俄、星、台、英、美)至2007年之資料以比較三個最常用之成長模型之績效，即Gompertz、Logistic及Bass模型。模型績效逐年比較標準係採用rmse值，並輔以Friedman test檢測模型績效差異之顯著性，再對照模型之機制意涵，以進一步了解最適模型之選用原則。 此外，台灣行動電話普及率於2002年為108%居全球之冠，而中國自2001年起取代美國成為全球具最多行動電話用戶數之單一國家，台灣及中國屬行動電話擴散之重要個案，惟目前尚缺此二個案之實證研究。為補足此一缺口，本研究亦對台灣及中國行動電話擴散之驅動因子進行實證研究，以進一步了解擴散之關鍵驅動力。 研究發現由於目前統計軟體之進步，Gompertz、Logistic及Bass三模型均可獲致極佳之匹配度而難分軒輊，惟模型預測力(延伸曲線)則具差異性。12個模型選用樣本國家中之8個國家(巴、中、法、德、日、韓、英、美)係以Gompertz模型具較佳之預測力；依Gompertz模型機制意涵，代表行動電話擴散早期係受網路外部性(口耳相傳)影響，惟至擴散後期(例如過了擴散極大值之一半)則已不相關。此外，若因市場開放等重大變因造成行動電話之快速擴散，則Logistic模型具有較佳之績效，如台灣及俄羅斯屬之。依Logistic模型機制意涵，代表擴散係受網路外部性所影響。Bass模型應用於行動電擴散時，因該模型所算出之創新係數偏低，績效與Logistic模型相近，而Logistic模型為Bass模型之創新係數為0時之特例。 台灣及中國行動電話擴散之驅動因子研究發現(1)價格下降及(2)預付卡之推行對加速擴散具顯著性，兩者均對低階市場之採用具影響力。鑑於高階市場將先飽和，爰未來加速行動電話擴散之關鍵驅動因子應係與推動低階市場採用具密切相關性。以中國為例，未來市場開放競爭造成價格再度大幅下降，將進一步促低階市場採用，加速中國行動電話之普及。 / The number of mobile telephone subscriptions reached 1.2 billion globally in 2002, exceeding fixed-line telephony subscriptions (1.1 billion) for the first time. The number of mobile telephone subscriptions reached 4.1 billion globally in 2008, over three times the number of fixed-line telephone subscriptions (1.3 billion). The main advantages of mobile telephony over fixed-line are low cost and rapid facility deployment. The rapid diffusion of mobile telephony has become an important topic in innovation diffusion. The conventional approach to studying mobile telephony diffusion is to analogize a single growth model, such as the Gompertz, Logistic or Bass model, and calculate the model parameters, for example growth rate. The significance of certain selected driving forces, such as technology innovation or market competition, to the studied parameters, such as growth rate, is then estimated. The diffusion growth can also be forecast by extrapolating the diffusion curve. Utilizing the growth model analogy is the first step in analyzing mobile telephony diffusion. However, no principles or rules exit for selecting a growth model. To identify rules for model selection to reduce randomness and increase forecast accuracy, this work uses 12 sample countries, namely Brazil, China, France, Germany, India, Japan, Korea, Russia, Singapore, Taiwan, the UK and the USA, employing data prior to 2008 to compare the performance of three most commonly used models, namely the Gompertz, Logistic and Bass models. The root mean square error (rmse) is chosen as the criterion for measuring annual model performance. The work uses the Friedman test to examine the significance of differences in performance between models. The implications of model mechanisms are emphasized to investigate the selection rule for the most appropriate model. The penetration of mobile telephony in Taiwan was 108% in 2002, ranking first in the world. Furthermore, in 2001 the number of mobile telephony in China replaced the United States as number one in the world. Both Taiwan and China are important examples for mobile telephony diffusion. However, no empirical investigation has been performed in these two cases. To fill this gap, this work estimated the driving forces for mobile telephony diffusion in Taiwan and China to learn about the critical drivers of the mobile telephony diffusion. Empirical results indicate that due to improvements in statistical software, providing good fitness for all three models, namely the Gompertz, Logistic and Bass models, distinguishing which has the best fitness is difficult. However, the performance of the three models is distinguishable when forecasting based on extrapolating the diffusion curve. In eight of the 12 examples, namely Brazil, China, France, Germany, Japan, Korea, the UK and the USA, the Gompertz model is the most appropriate model for forecasting. The mechanism of the Gompertz model means that during the initial stage the diffusion is correlated with network externalities (namely word of mouth), however, this correlation reduces during the later stages (such as pass one half of the maximum potential). Moreover, the cases of Taiwan and Russia demonstrated that the Logistic model performs well provided some significant driver of the diffusion exists. The mechanism of the Logistic model means that the diffusion is correlated with network externalities throughout the whole diffusion. Furthermore, using Chinese data, when the Bass model is applied, because of its low innovation coefficient, it performs similarly to the Logistic model, which is a special case of the Bass model in which the innovation coefficient equals zero. Empirical results for the critical driving forces of mobile telephony diffusion in Taiwan and China indicate that (1) reducing prices and (2) the launch of pre-paid services are crucial to mobile telephony diffusion. Both factors are essential to mobile telephony adoption in low-end markets. The high-end market is the first to be saturated by mobile telephony adoption, future drivers of the mobile telephony diffusion should be highly correlated with low-end market demand. Taking China as an example, the opening of the market to further reduce tariffs will attract mobile telephony adoption in the low-end market, facilitating the mobile telephony diffusion.