Any device connected to the Internet needs to be protected. Using a firewall as a first line of defence is a very common way to provide protection. A firewall can be set up to protect an entire network or just a single host. As it is becoming more and more popular to connect mobile phones and other hand held devices to the Internet, the big question is;"how to protect those devices from the perils of the Internet?" This work investigates issues with the implementation of a firewall system for protecting mobile devices. Firewall administration is an error prone and difficult task. Setting up a correctly configured firewall in a network setting is a difficult task for a network administrator. To enable an ordinary mobile phone user to set up a firewall configuration to protect his mobile phone it is important to have a system that is easy to understand and warns the user of possible mistakes. Generic algorithms for firewall rule-set sorting and anomaly discovery are presented. This ensures that the rule-set is error free and safe to use. This is a vital part of any firewall system. The prototype developed can be used to find errors in existing firewall rule-sets. The rule-set can be in either a native firewall configuration format (currently only IPF is supported) or in a generic XML format. This generic XML format was developed as a part of this research project. Further a new graphical visualization concept that allows the end user to configure an advanced firewall configuration from a device with a small screen and limited input possibilities is presented.

Yes / A tuneable slotted patch antenna design is presented and verified for use in the DCS, PCS and UMTS bands. The tuning circuit consists of two varactor diodes with some passive components, and is integrated fully with the r radiator patch, with the varactors occupying different locations over the slot. The tuning does not require any further modification to the patch or feed geometry. Good agreement is observed between the predicted and observed impedance bandwidth, return loss, gain and radiation pattern, throughout the range 1.70 GHz-2.05 GHz.

Yes / This work develops a novel dynamic load modulation Power Amplifier (PA) circuity that can provide an optimum compromise between linearity and efficiency while covering multiple cellular frequency bands. Exploiting monolithic microwave integrated circuits (MMIC) technology, a fully integrated 1W Doherty PA architecture is proposed based on 0.1 µm AlGaAs/InGaAs Depletion- Mode (D-Mode) technology provided by the WIN Semiconductors foundry. The proposed wideband DPA incorporates the harmonic tuning Class-J mode of operation, which aims to engineer the voltage waveform via second harmonic capacitive load termination. Moreover, the applied post-matching technique not only reduces the impedance transformation ratio of the conventional DPA, but also restores its proper load modulation. The simulation results indicate that the monolithic drive load modulation PA at 4 V operation voltage delivers 44% PAE at the maximum output power of 30 dBm at the 1 dB compression point, and 34% power-added efficiency (PAE) at 6 dB power back-off (PBO). A power gain flatness of around 14 ± 0.5 dB was achieved over the frequency band of 23 GHz to 27 GHz. The compact MMIC load modulation technique developed for the 5G mobile handset occupies the die area of 3.2. / This research was funded by the European Regional Development Fund (FEDER), through COMPETE 2020, POR ALGARVE 2020, Fundação para a Ciência e a Tecnologia (FCT) under i-Five Project (POCI-01-0145-FEDER-030500). This work is also part of the POSITION-II project funded by the ECSEL joint Undertaking under grant number Ecsel-345 7831132-Postitio-II-2017-IA. This work is supported by FCT/MCTES through national funds and when applicable co-funded EU funds under the project UIDB/50008/2020-UIDP/50008/2020. The authors would like to thank the WIN Semiconductors foundry for providing the MMIC GaAs pHEMT PDKs and technical support. This work is supported by the Project TEC2017-88242-C3-2-R- Spanish Ministerio de Ciencia, Innovación e Universidades and EU-FEDER funding.

This thesis proposes a variety of antenna designs suitable for modern of mobile products, such as mobile phones, PDAs and so forth, on both the 2G and 3G communication systems according to the mobile communication development. Based on the integration of monopole or planar inverted-F antenna with the system ground planes, multi-frequency, broadband, and high radiation efficiency can be achieved, which is very promising to be adapted into communication products. Furthermore, an antenna capable of WLAN and UWB is proposed for future wireless communication applications.

In this thesis, the study mainly focuses on developing multiband chip antennas for mobile handsets. Three possible solutions and their extended and integrated designs are presented. By using the dielectric material as the chip base, the chip antenna can be smaller in size and simpler in design. Most of the applications of the traditional chip antennas are rarely used as the mobile phone antenna and are commonly designed with a single operating band to cover GPS or WLAN operation only. Different types of the antennas are proposed in the thesis. The metal patterns of the monopole and loop antennas are manufactured inside the chip base with an occupied volume of generally less than 0.8 cc, some even as small as 0.3 cc. Electronic components like the lens of the embedded camera and the speaker can be integrated close to the chip antenna with little influences on the radiation characteristics. Consequently, the developed chip antennas are suitable for mobile communications and can cover not only GSM850/900/1800/1900/ UMTS bands but also WLAN/WiMAX bands.

京都大学 / 0048 / 新制・課程博士 / 博士(経済学) / 甲第18760号 / 経博第511号 / 新制||経||273(附属図書館) / 31711 / 京都大学大学院経済学研究科経済学専攻 / (主査)教授 椙山 泰生, 教授 日置 弘一郎, 教授 武石 彰 / 学位規則第4条第1項該当 / Doctor of Economics / Kyoto University / DGAM

Tο αντικείμενο της διδακτορικής διατριβής είναι η μελέτη και σε βάθος ανάλυση και μοντελοποίηση της ηλεκτρομαγνητικής αλληλεπίδρασης του ανθρώπινου σώματος και των κεραιών που χρησιμοποιούν οι φορητές τερματικές συσκευές των σύγχρονων συστημάτων κινητής τηλεφωνίας. Ο στόχος είναι διπλός: αφενός μεν να υπολογιστεί η υποβάθμιση της απόδοσης της κεραίας, που προκαλείται από την παρουσία του σώματος του χρήστη σε μικρή απόσταση από αυτή και αφετέρου να εξεταστεί και να προσδιοριστεί επακριβώς το ποσό της ηλεκτρομαγνητικής ακτινοβολίας που απορροφάται από το ανθρώπινο σώμα και ειδικότερα από τον ανθρώπινο εγκέφαλο κατά τη χρήση του κινητού τηλεφώνου. Ο απώτερος σκοπός είναι η συμβολή στην ανάπτυξη ασύρματων τερματικών (πχ. κινητά τηλέφωνα) που θα είναι πιο αποδοτικά στη λειτουργία τους και ταυτόχρονα περισσότερο ασφαλή για το χρήστη τους. Στην παρούσα διδακτορική διατριβή πραγματοποιήθηκε εκτενής μελέτη και ανάλυση των παραμέτρων που σχετίζονται με την αλληλεπίδραση μεταξύ της κεραίας ασύρματων τερματικών συσκευών και του σώματος του χρήστη. Σχεδιάστηκαν, μοντελοποιήθηκαν, υλοποιήθηκαν και μετρήθηκαν πειραματικά πρωτότυπα τερματικών συσκευών παρουσία ομοιωμάτων του ανθρώπινου κεφαλιού με σκοπό τον υπολογισμό της απορρόφησης ακτινοβολίας από το κεφάλι και της μεταβολής της απόδοσης της κεραίας του τερματικού. Αναπτύχθηκε κατάλληλη μεθοδολογία μετρήσεων στο μακρινό πεδίο για την αξιόπιστη και ακριβή μέτρηση των χαρακτηριστικών των κεραιών του τερματικού. Τα αποτελέσματα έδειξαν έντονη αλλαγή των χαρακτηριστικών της κεραίας και του διαγράμματος ακτινοβολίας της, παρουσία του κεφαλιού του χρήστη. Επίσης, υπολογίστηκε η απότομη πτώση της απορρόφησης ακτινοβολίας και η αύξηση της απόδοσης με την απομάκρυνση του τερματικού από το κεφάλι. Επιτεύχθηκε σημαντική βελτίωση της λειτουργίας μέσω της μορφοποίησης του διαγράμματος ακτινοβολίας που κατορθώνεται με τη χρήση πολλαπλών κεραιών (συστοιχία) στο τερματικό. Τέλος εξετάστηκε η επίδραση του χεριού του χρήστη στην απόδοση ενός ΜΙΜΟ τερματικού και βρέθηκε μείωση της μέσης χωρητικότητας του καναλιού με την παρουσία του χεριού. / Τhe object of this doctoral thesis is the study, in depth analysis and modelling of the electromagnetic interaction between the human body and the antennas used in the handsets of modern wireless telecommunication systems. The aim is twofold. On one hand is the estimation of the antenna efficiency reduction that is caused by the presence of the user’s body in small distance and on the other hand is the study and precise determination of the electromagnetic radiation absorbed by the human body (especially the human head) at the use of a wireless terminal. The final aim is the contribution in the design of wireless terminals (e.g. mobile telephones) that will be more efficient in their operation and simultaneously safer for their user. In this thesis, an extensive study and analysis of the parameters related with the interaction between the wireless terminal antenna and the user’s body were realized. Experimental terminal prototypes were designed, modelled, constructed and measured in the presence of human head models in order to estimate the radiation absorption from the head and the degradation of the antenna efficiency. An appropriate measurements methodology at the far field was developed for the precise measurement of the terminal antenna characteristics. According to the results, an intense change of the antenna characteristics and of its radiation diagram in the presence of the user’s head was observed. Also, the rapid decrease of absorbed power and the increase of the efficiency were calculated after moving the handset away from the head. An important operation improvement was achieved with beamforming, which is realized using multiple antennas at the terminal. Finally, the effect of the user’s hand at MIMO terminal performance was examined and a reduction of the mean capacity of the channel in the presence of the hand was found.

The main objectives of this research are to investigate and design low profile antennas for mobile handsets applications using the balanced concept. These antennas are considered to cover a wide range of wireless standards such as: DCS (1710¿1880 MHz), PCS (1850¿1990 MHz), UMTS (1920¿2170 MHz), WLAN (2400¿2500 MHz and 5000 ¿ 5800 MHz) and UWB frequency bands. Various antennas are implemented based on built-in planar dipole with a folded arm structure. The performance of several designed antennas in terms of input return loss, radiation patterns, radiation efficiency and power gain are presented and several remarkable results are obtained. The measurements confirm the theoretical design concept and show reasonable agreement with computations. The stability performance of the proposed antenna is also evaluated by analysing the current distribution on the mobile phone ground plane. The specific absorption rate (SAR) performance of the antenna is also studied experimentally by measuring antenna near field exposure. The measurement results are correlated with the calculated ones. A new dual-band balanced antenna using coplanar waveguide structure is also proposed, discussed and tested; this is intended to eliminate the balanced feed network. The predicted and measured results show good agreement, confirming good impedance bandwidth characteristics and excellent dual-band performance. In addition, a hybrid method to model the human body interaction with a dual band balanced antenna structure covering the 2.4 GHz and 5.2 GHz bands is presented. Results for several test cases of antenna locations on the body are presented and discussed. The near and far fields were incorporated to provide a full understanding of the impact on human tissue. The cumulative distribution function of the radiation efficiency and absorbed power are also evaluated. / UK Engineering and Physical Sciences Research Council (EPSRC)

The main objectives of this research are to investigate and design low profile antennas for mobile handsets applications using the balanced concept. These antennas are considered to cover a wide range of wireless standards such as: DCS (1710-1880 MHz), PCS (1850-1990 MHz), UMTS (1920-2170 MHz), WLAN (2400-2500 MHz and 5000-5800 MHz) and UWB frequency bands. Various antennas are implemented based on built-in planar dipole with a folded arm structure. The performance of several designed antennas in terms of input return loss, radiation patterns, radiation efficiency and power gain are presented and several remarkable results are obtained. The measurements confirm the theoretical design concept and show reasonable agreement with computations. The stability performance of the proposed antenna is also evaluated by analysing the current distribution on the mobile phone ground plane. The specific absorption rate (SAR) performance of the antenna is also studied experimentally by measuring antenna near field exposure. The measurement results are correlated with the calculated ones. A new dual-band balanced antenna using coplanar waveguide structure is also proposed, discussed and tested; this is intended to eliminate the balanced feed network. The predicted and measured results show good agreement, confirming good impedance bandwidth characteristics and excellent dual-band performance. In addition, a hybrid method to model the human body interaction with a dual band balanced antenna structure covering the 2.4 GHz and 5.2 GHz bands is presented. Results for several test cases of antenna locations on the body are presented and discussed. The near and far fields were incorporated to provide a full understanding of the impact on human tissue. The cumulative distribution function of the radiation efficiency and absorbed power are also evaluated.

本研究的個案是系統單晶片企業，系統單晶片是電子系統的核心，因此該企業對於下游電子產品的發展扮演著舉足輕重的角色，是積體電路產業價值鍊最高價值的一環。本研究的主要目的是藉著一個極為成功的系統單晶片設計公司的成長軌跡與其相關的產業歷史，透過還原當時的時空環境了解並分析其經營策略的本質，以建立適合系統單晶片設計公司之經營策略本質的分析架構，同時實證其分析的結果，藉以尋求其研究問題「後進者的成功經營策為何?」的解答，並從個案企業的歷史中找出常被忽略的寶貴的經營智慧，而另一目的是能夠藉著收集具有時間標記的經營事件，提供豐富的研究素材給有興趣系統單晶片設計產業做更進一步或其他主題的研究。 一開始的動機是為了解答「後進者的成功經營策為何?」這個問題，但研究之後發現這是一個很有可能沒有通用解的問題，因此本研究轉從「策略本質的思考」出發，試著從個案公司的各個不同系統單晶片產品及其下游相關的產業的事件中，進行分析、推理、歸納與實證所關心的議題，其中個案分析主要包括四個產業：（一）光碟機產業；（二）DVD播放機產業；（三）數位電視機產業；（四）手機產業。其中每一個產業的故事都以某一個案的企業發展為中心，以時間的先後呈現，描述當時的產業環境、企業狀態、決策的因果關係，以及如何執行與執行結果。為了解答「後進者的成功經營策為何?」這個的大問題，同時從個案的分析與理論推論研究，從不同方向的思考並嚴謹的歸納與分析提出以下的研究發現：（一）從行銷理論分析策略本質；（二）以利潤方程式分析策略本質；（三）SOC晶片訂價策略；（四）從動態能耐的架構分析策略本質；（五）後進者的經營策略；（六）成長與新產品選擇的策略；(七)經營智慧的闡述。希望能提供企業經營者策略思考的架構，而建構出適合自己的經營策略。 本研究藉著邱志聖「行銷理論」中產品的「外顯」與「內隱」之價值分析方法，發展出「（一）從行銷理論分析策略本質」之研究發現中一系列的理論，並以此為基礎，輔助論證其他的研究發現，再根據「利潤彈性」的定義，提出可以以嚴謹的數學証明的一系列有關訂價的創新的理論，以此為基礎進而提出「（三）SOC晶片訂價策略」，再藉著「（四）從動態能耐的架構分析策略本質」的個案研究，發現組織的能耐與低成本優勢有的強烈的相關性，整合以上相關的研究發現，進而提出「（五）後進者的經營策略」，以創新「先進者支援的兩難」理論為切入點，並根據以上研究的結論，提出「後進者的成功經營策為何?」的參考解答。當企業成功之後，必然會面臨成長的困境，因此本研究從個案的深入分析，提出所應採取的「（六）成長與新產品選擇的策略」，以及最後提醒經營者一些知易行難的「(七)經營智慧的闡述」。 根據TEEC的「動態能耐」的理論，企業的策略深受「路徑相依性」的影響，且當不同企業的內部狀態或外部環境不同時其所需的策略也不一樣，因此後進者僅採用模仿的策略是不易成功，所以企業必需要思索適合自身的策略，並透過策略本質的分析，檢驗其策略是否有效，然而任何策略分析的方法都有其盲點，因 此分析或擬定策略時要依據競爭對手與產業特性選數種適合分析的架構進行分析，才能夠互相印證與互補，並思考其矛盾之處以避免致命的盲點，因此本論文提出專為系統單晶片設計企業策略本質的思考之架構以檢驗其策略有效性。 / The System on Chip (SOC) is the core of the electric system of an electric end product. Therefore, the firms that design and produce the SOC play the critical role in the development of the end product and contribute the most valuable part in the IC industry chain. The purposes of this paper are to develope the strategies and wisdoms of management as well as the frame structure for analyzing the essence of management strategies for the late comer. In the case study, there are the companies have been very successful in the world. In the cases, there are a lot of time-marked traces of the growth of the successful firm and its related industry history so that we can clarify what and why the strategies were executed at that time by analyzing the sequences of the management decisions and their consequences. Additionally, I hope the case stories can be utilized for the further research or another related research. Initially in this research we focused only on the topic of the question“What are the effective management strategies for the late comer”. However, after further studies we found that the general answers for the big question might not exit; therefore, we adjusted the research direction and converted to focus on the topic of the essence of the analysis of the management strategies. In the studied case, there are four different kinds of SOC products including optic storage chip, DVD player chip, digital TV chip and handset chip and their related industries. In the story of each product case, the main stream of the story keeps close track of the situation of the management decisions making, the status of the execution by the studied firms and their consequences in timing sequence so that the evolution of the environment of the firms and the industries can be shown clearly. To study for the answer of the big question “What are the effective management strategies for the late comer”, firstly we analyze the cases and simultaneously study the related theories. Secondly we transform the big question into the following seven research subtopics: (1) Analyzing the essence of the management strategies based on the marketing promotion theory, (2) Analyzing the essence of the management strategies by the net profit, (3) Pricing strategies for the SOC products, (4) Analyzing the essence of the management strategies by the perspective of the“Dynamic capabilities”, (5) Management strategies for the late comer, (6) Strategies for the growth and new products selection, and (7) Wisdom of management. Finally, we hope this thesis can provide managers with the frame structure for both thinking and analyzing the strategies so that managers can develop the best strategies for themselves. There are some kinds of logical relation among the theories developed in the above subtopics. The foundation of theories of“Analyzing the essence of the management strategies”is the value proposition that bases on the analysis of the explicit value and implicit value in the marketing promotion theory. Theories of“Analyzing the essence of the management strategies”are one of the most fundamental pillars that support the other theories in this thesis. According to the definition of elasticity of net profit in this thesis, we can deduce some innovative and valuable theories by the rigid mathematical reasoning. Furthermore, we can develop the innovative theories “(3) Pricing strategies for the SOC product”. In addition to developing the above theories, we apply the theory of “Dynamic capabilities” to analyze the strategies in the case stories to find the effective cost advantage is supported by the capabilities of organization with effectiveness and efficiency. We integrate the above theories to propose “(5) Management strategies for the late comer”. A firm will eventually confront the saturation of the growth after its successful startup. To solve this issue, we base on the deep investigation of the cases and some theories developed in this thesis, we propose “(6) Strategies for growth as well as new products selection”. Finally from the case stories, we abstract some both valuable and critical wisdoms that are easy understood but they are hard to be practiced due to the human natural weakness. According to “Dynamic Capabilities and Strategic Management” by TEECE, the strategies for a firm strongly depend on the path that the firm has experienced, thus the imitative strategies from its rival is usually not effective just because their paths they passed are different, not to mention that neither their environments nor the conditions of the firms are totally different. Therefore, a firm works out any strategies and then its managers have to carefully check the effectiveness of the strategies by analyzing their essence of the strategies and then modify them before they are executed. However, any framework for analyzing strategy has its blindspots. To avoid the strategic blindspots, we have to use several different and suitable frameworks to analyze the strategies, and then check if there are any conflicts among the results from different frameworks analyzing, we have to deliberate to find why and how to solve the conflicts. Therefore, we develop a new frame work that appropriately analyzes the strategies of both the SOC firm-level and their products with a totally different perspective