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Telecom wavelength quantum devicesFelle, Martin Connor Patrick January 2017 (has links)
Semiconductor quantum dots (QDs) are well established as sub-Poissonian sources of entangled photon pairs. To improve the utility of a QD light source, it would be advantageous to extend their emission further into the near infrared, into the low absorption wavelength windows utilised in long-haul optical telecommunication. Initial experiments succeeded in interfering O-band (1260—1360 nm) photons from an InAs/GaAs QD with dissimilar photons from a laser, an important mechanism for quantum teleportation. Interference visibilities as high as 60 ± 6 % were recorded, surpassing the 50 % threshold imposed by classical electrodynamics. Later, polarisation-entanglement of a similar QD was observed, with pairs of telecom-wavelength photons from the radiative cascade of the biexciton state exhibiting fidelities of 92.0 ± 0.2 % to the Bell state. Subsequently, an O-band telecom-wavelength quantum relay was realised. Again using an InAs/GaAs QD device, this represents the first implementation of a sub-Poissonian telecom-wavelength quantum relay, to the best knowledge of the author. The relay proved capable of implementing the famous four-state BB84 protocol, with a mean teleportation fidelity as high as 94.5 ± 2.2 %, which would contribute 0.385 secure bits per teleported qubit. After characterisation by way of quantum process tomography, the performance of the relay was also evaluated to be capable of implementing a six-state QKD protocol. In an effort to further extend the emitted light from a QD into the telecom C-band (1530—1565 nm), alternative material systems were investigated. InAs QDs on a substrate of InP were shown to emit much more readily in the fibre-telecom O- and C-bands than their InAs/GaAs counterparts, largely due to the reduced lattice mismatch between the QD and substrate for InAs/InP (~3 %) compared to InAs/GaAs (~7 %). Additionally, to minimize the fine structure splitting (FSS) of the exciton level, which deteriorates the observed polarisation-entanglement, a new mode of dot growth was investigated. Known as droplet epitaxy (D-E), QDs grown in this mode showed a fourfold reduction in the FSS compared to dots grown in the Stranski-Krastanow mode. This improvement would allow observation of polarisation-entanglement in the telecom C-band. In subsequent work performed by colleagues at the Toshiba Cambridge Research Labs, these D-E QDs were embedded in a p-i-n doped optical cavity, processed with electrical contacts, and found to emit entangled pairs of photons under electrical excitation. The work of this thesis provides considerable technological advances to the field of entangled-light sources, that in the near future may allow for deterministic quantum repeaters operating at megahertz rates, and in the further future could facilitate the distribution of coherent multipartite states across a distributed quantum network.
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Estrutura societária e controle minoritário na Brasil Telecom: análise do poder exercido pelo Opportunity de 2003 a 2005Belline, Alexandra Cisotto 09 May 2016 (has links)
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Previous issue date: 2016-05-09 / Since the mid-1990s the Brazilian business environment has experienced a significant increase in the sophistication of modeling corporate structures for large enterprises, a type of knowledge, however, mostly restricted to participants in these ventures and its legal and financial counsel. In the case of the corporate structure of Brazil Telecom, however, it was possible to access all documents and information in order to study this structure, due to the massive litigation involving this company for almost ten years , where most part of the documents analyzed in this dissertation were found. This material is precious because the case of Brazil Telecom - known as one of the major in Brazilian corporate law - has a very important peculiarity: the group was managed by a minority shareholder, Opportunity group, which exercised power control during those ten years, despite its diminished equity interest and strong opposition suffered from major shareholders for most of the time in which that power was exercised. The aim of this study is to reveal the legal techniques that allowed the exercise of this power, as well as to seek to understand why, in spite of so much opposition from other shareholders and the massive litigation, it took years for the Opportunity to be definitely removed from the administration and the exercise of controlling power of Brazil Telecom. / Desde meados dos anos 1990 o ambiente de negócios brasileiro tem passado por um relevante incremento na sofisticação da modelagem de estruturas societárias para grandes empreendimentos, um tipo de conhecimento que, porém, fica na maior parte restrito aos participantes desses empreendimentos e seus assessores jurídicos e financeiros. No caso da estruturação societária da Brasil Telecom, entretanto, foi possível ter acesso a todos os documentos e informações necessários ao estudo dessa estrutura, devido à enorme quantidade de litígios judiciais em que essa companhia esteve envolvida por quase dez anos, nos quais se pode obter a maior parte dos documentos analisados neste trabalho. Esse material é precioso, pois o caso da Brasil Telecom, conhecido como um dos maiores do direito societário brasileiro, tem uma peculiaridade muito importante: o grupo era gerido por um acionista minoritário, o grupo Opportunity, que exerceu poder de controle durante esses dez anos, apesar de sua diminuta participação societária e da forte oposição que sofreu dos acionistas majoritários por quase todo o tempo em que exerceu esse poder. O objetivo desse trabalho é revelar as técnicas jurídicas que permitiram o exercício desse poder, bem como buscar entender por que, apesar de tanta oposição dos demais acionistas e da enorme litigiosidade, anos transcorreram até que o Opportunity fosse definitivamente afastado da administração e do exercício do poder de controle da Brasil Telecom.
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電信私有化的政治邏輯︰以英國、俄羅斯與台灣為例 / Political logic of telecom privatization in UK, Russia and Taiwan羅彥傑 Unknown Date (has links)
自1980年代以降,私有化成為跨國、跨區域的全球化現象。在各種國公營事業私有化中,電信私有化堪稱是其中最具政治意涵的項目之一,其遭遇的政治阻力也最大。有鑑於過去相關研究多半側重意識型態、制度或利益團體等單一途徑,本研究嘗試統合理念、制度與利益等途徑,以完整的政治分析架構來解釋影響電信私有化三面向-進展速度、成功機率與順暢性-的最重要條件,建構電信私有化的政治理論。
衡量理念的兩項指標為「電信私有歷史遺緒」與「執政者(黨)連任勝選幅度」。衡量制度的兩項指標為「政治權力融合」與「資本市場體質」。衡量利益的兩項指標為「首次釋股套利誘因」與「全民與員工釋股」。若研究個案同時具備這兩項指標或表現較優,意味該個案在該面向上的表現也可能較佳。若個案不具備這兩項指標或表現較遜,意味該個案在該面向上的表現也可能較差。若個案僅具備其中一項指標或僅一項指標較佳,意味該個案在該面向上的表現可能持平。
作者發現,從英國、俄羅斯與台灣電信私有化過程的實際表現而言,理念、制度與利益確實能解釋三國在電信私有化進展速度、成功機率與順暢性上的差異。換言之,若欲迅速、成功與順利推動電信私有化,端視該國的理念、制度與利益而定。雖然理念不易改變,但政府可先從制度與利益著手。制度對電信私有化政策發揮「制度承諾」的效果,而利益則扮演策略性誘因的角色,對電信私有化政策發揮「利益分配」的效果。尤其,利益分配愈普遍、愈讓全民與電信員工有利可圖,電信私有化愈能獲得市場與投資人認同,愈能化解阻力。本研究建議,政府應逆向思考,唯有在首次釋股時先「賤賣」電信資產給全民與員工,電信私有化方能順利推動。 / Privatization has become international and interregional phenomena since 1980s. Among the privatizations of all state-owned and public enterprises, telecom ones can be described as one of the most political implications, facing more political resistance than others. Given the fact that the past researches mostly focused on such single approaches as ideology, institutions and interest groups, this study tries to integrate idea, institutions and interests into a political analytical framework. This study hopes to answer the key prerequisites affecting telecom privatization’s three dimensions-speed, success and smoothness, constructing the political theory of telecom privatization.
Two indicators of measuring “idea” are “telecom assets historically privately-owned” and “re-elected ruler (or ruling party)’s winning margins”. Two indicators of measuring “institutions” are “fusion of political powers” and “health of capital markets”. Two indicators of measuring “interests” are “arbitrage incentives during first shares sale” and “offering shares to individual investors and employees”. If the case is simultaneously qualified for two indicators, it means the case could perform well in that dimension, and vice versa. If the case only satisfies one indicator, it means the case could perform intermediately.
The author found that as far as the results of telecom privatizations in United Kingdom, Russia and Taiwan are concerned, idea, institutions and interests actually are able to explain the difference of the three cases in terms of speed, success and smoothness. In other words, a speedy, successful and smooth telecom privatization depends on idea, institutions and interests. Although it is difficult to change idea, the governments can begin with institutions and interests. Institutions play the “commitment” role, and interests show the “allocation” effect. In particular, the more broadly interests being allocated, and the more profitable individual investors and employees obtaining from telecom privatization, the less opposition the government encountering. The study suggests that the government think of telecom privatization reversely. Telecom privatizations can be pressed ahead smoothly only with “cheaply selling” telecom assets to individual investors and employees during first shares offering.
Keywords: Telecom privatization, idea, institution, interest, arbitrage.
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創業計畫:新型電信業商品綑綁模式 / Business Plan: A New bundling Product model in Taiwan telecom market張薷云, Chang, Paris J.Y Unknown Date (has links)
As the digital convergence trend comes and the deregulation of telecom industry, it becomes more competitive in telecom market in Taiwan. The telecom industry now is not limited to voice service but mobile internet, broadband internet and even video contents. The business expansion and marketing resource allocation somehow become a conflict under the strong competition. This business plan is to a new bundling Product model in Taiwan telecom market to overcome the conflict. To make it more specific and practical, all assumptions are under the current business condition of Chunghwa telecom.
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中華電信與高盛的外匯選擇權避險合約 / Chunghwa Telecom's Hedge Contract with Goldman Sachs顏子皓, Yen, Tzuhao Unknown Date (has links)
2007年是中華電信企業民營化的第二年,如同以往地在業務面及財務面締造了佳績。然而,在2007年9月時,中華電信與香港高盛簽下一紙長達10年期的外匯避險合約,使得中華電信在隔年第一季公佈高達新台幣40億元的未實現匯兌損失,引起市場一片譁然與投資人的輿論,認為此合約讓收入多以新台幣計價的中華電信陷入了不必要的衍生性商品陷阱之中。本個案讓閱讀者以當時中華電信財務長謝劍平的角度,帶領閱讀者解構、分析這個極具爭議的的結構型商品。過程中牽涉到避險決策、契約評價、代理問題、公司治理、外匯預測、市場效率性等議題。2008年10月契約觸及匯價32.7終止,中華電信最終獲利新台幣3010萬元出場,新台幣10多億的帳面損失也全數回沖。個案閱讀者能從中學習到重要的思考過程,並做出權衡之下對股東利益最好的決策,我們發現這個外匯避險契約本身並無絕對好壞,因為這是一個風險控管與節省成本的抵換關係,端看決策者的出發點、需求及風險偏好決定。 / 2007 was the second year after the privatization of Chunghwa Telecom, the financial performance was strong as usual. However, on September of the same year, Chunghwa Telecom had signed a 10-year currency hedging contract with Goldman Sachs, which leads to NTD 4 billion unrealized book losses in the first season of 2008. Investor and the public were shocked about it, because it was not compatible with the company’s corporate image, and the book losses was too huge. Many public opinion criticized that it was a big mistake for Chunghwa Telecom, which let them fall into the trap of financial derivatives. This case put students back to the scenario of September 2007, played the role as Chunghwa Telecom’s CFO, CP Shieh. The case will guide them understand how to decompose and analyze a tailor made structure product provided by investment bank. In the analyzing process, readers will involve many interesting issues, like hedging decision, contract valuation, agency problem, corporate governance, forex forecasting and market efficiency. October 2008, the contract knocked out by reaching NTDUSD quote 32.7. Chunghwa Telecom end up gained NTD 30.1 million from the contract and over NTD 1 billion unrealized book losses were also reversed. Case readers can acquire important intuition during the analyzing process and make decision based on the shareholder’s best interest. There is no absolute answer to dictate whether this hedging contract was good or not, because it was a tradeoff between risk control and cost saving. It depends on the decision maker’s point of view, demand and risk preference.
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The Impact of Universal Service Obligations and Other External and Cross Subsidies on Teledensity in Developing CountriesRamos, Boris G. 31 May 2006 (has links)
"The failure to consider the complexity of the regional telecommunication systems in planning has increased the telecom gap between other regions and the rural sectors in the developing countries. Earmarked funds generated by Universal Service Obligations and various types of other direct and cross-subsidies have not helped this situation. This research uses system dynamics modeling approach to understand the complexity of the system and to evaluate how different policies affect telephone densities. It is demonstrated that some of the prevalent policies may be counterproductive. Policy experiments with the model demonstrate that market-clearing pricing implemented with Universal Service Obligations, and a value-added service combination may significantly improve rural telecommunications."
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The Impact of Universal Service Obligations and Other External and Cross Subsidies on Teledensity in Developing CountriesRamos, Boris G. 31 May 2006 (has links)
"The failure to consider the complexity of the regional telecommunication systems in planning has increased the telecom gap between other regions and the rural sectors in the developing countries. Earmarked funds generated by Universal Service Obligations and various types of other direct and cross-subsidies have not helped this situation. This research uses system dynamics modeling approach to understand the complexity of the system and to evaluate how different policies affect telephone densities. It is demonstrated that some of the prevalent policies may be counterproductive. Policy experiments with the model demonstrate that market-clearing pricing implemented with Universal Service Obligations, and a value-added service combination may significantly improve rural telecommunications."
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Techniques MIMO pour un lien sans l robuste entre un bus et un poste de contrôle pour une application de surveillance embarquéeMoniak, G. 07 February 2007 (has links) (PDF)
Ce travail concerne un lien de communication sans l depuis des bus urbains vers un ou plusieurs postes de contrôle pour des applications d'audio et de vidéo surveillance. La solution imaginée s'appuie sur les techniques MIMO et OFDM. Nos travaux se décomposent en trois axes principaux : L'étude et la modélisation du canal de propagation MIMO en milieu urbain dense, le développement et l'évaluation en simulation d'une chaîne de transmission MIMO, le développement d'une chaîne de transmission réelle pour des essais grandeur nature. Un état de l'art sur le canal de propagation MIMO et sa modélisation est d'abord présenté. Des mesures de canaux réels correspondant à un environnement transport ont été réalisées. L'émetteur de la chaîne de transmission réalisée s'inspire du standard WiMAX. En réception, un récepteur simple aux performances moyennes et un Turbo récepteur plus performant mais plus complexe sont étudiés. Plusieurs types de canaux ont été utilisés pour l'évaluation de la chaîne. Les résultats en simulation montrent un Turbo récepteur plus performant en termes de taux d'erreurs, plus résistant aux erreurs d'estimation du canal et à la corrélation spatiale. Ils montrent également que la corrélation du canal a un impact prédominant sur la dégradation des performances de ce type de système comparé notamment à la présence d'un trajet prépondérant. En parallèle de ces travaux, une chaîne de transmission réelle a été développée. Elle est composée des parties radio fréquence du système et de PC générant et traitant les signaux. Les tests réalisés en milieu urbain montrent une dégradation des performances par rapport aux résultats de simulation. Des solutions alternatives sont proposées.
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Internet vs. Butik : En studie om bankers och mobiltelefonoperatörers verksamhet på internet / Internet vs. StoreBerglund, Martin, Englund, Adam January 2009 (has links)
<p><strong>Bakgrund: </strong>I bakgrunden framgår att formerna utbyte och kommunikation harförändrats över tiden. Fysiska butiker börjar i allt mer högre gradersättas av virtuella internetbutiker. Detta leder till att företagenförlorar det fysiska mötet med kunden.</p><p><strong>Problemformulering: </strong>Vilka faktorer är viktiga för företags långsiktiga överlevnad ochkundlojalitet när de använder internet som kommunikationsstrategi, och genom det förlorar det fysiska mötet med kunden?</p><p><strong>Syfte: </strong>Syftet med uppsatsen är att genom en hypotesprövning analysera och utvärdera formerna för utbyte som sker via internet mellan kund ochföretag.</p><p><strong>Metod: </strong>Uppsatsen utgår från en hypotetisk-deduktiv ansats. Kvantitativundersökningsmetod tillämpas i form av en kundenkät.</p><p><strong>Teorier: </strong>Uppsatsen använder följande teorier: Grundläggandekommunikationsteori, Involveringsteorin, Totalkommunikation,Värdestjärnan.</p><p><strong>Empiri: </strong>Empirin består uteslutande av primärdata från kundenkäten.</p><p><strong>Resultat: </strong>Resultatet visar att kunderna inte tycker att bank- ochtelekombranschens flytt ut på internet inte har försämrat möjlighetenför utbyte med företagen.</p><p><strong>Slutsats: </strong>De företag som lyckas skapa värde tillsammans med sina kunder viainternet, och som erbjuder en hög grad av interaktion i de nyakommunikationskanaler som skapas på internet, är de företag somkommer att nå långsiktig överlevnad.</p> / <p><strong>Background: </strong>In the background it is apparent that the forms for trade andcommunication have changed over time. Physical stores are beingphased out and are replaced by internet shops. This leads to a loss ofthe physical meeting between company and customer.</p><p><strong>Problem definition: </strong>What factors are important for company's long-term survival andcustomer loyalty, when they use internet as communication strategyand by that looses the physical meeting with the customer.</p><p><strong>Objective:</strong> The purpose of the essay is by a hypothesis test analyze and evaluatethe exchange that takes place on the internet between customer andcompany.</p><p><strong>Method: </strong>The essay will have a hypothesis-deductive approach. Quantitativemethods will be used as the form of a survey.</p><p><strong>Theories: </strong>The essay uses the following theories: A Mathematical Theory ofCommunication, Involvement Theory, Total Communication, Valuestar.</p><p><strong>Empiric: </strong>The empiric will have the form of a survey.</p><p><strong>Results: </strong>The results shows that the customer do not think the bank- andtelecom companies move out on the internet have change theopportunities to exchange with the companies.</p><p><strong>Conclusion: </strong>The companies that succeed in creating value together with theircustomers on the internet, and offer a high level of interactionswithin the new communication channels that are created on theinternet; these are the companies that will survey in the long term.</p>
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Identification and Analysis of Market Indicators : a predictive tool for anticipating future demand fluctuations on the telecom mobile network equipment market / Identifiering och analys av marknadsindikatorer : ett verktyg för att förutsäga framtida efterfrågeförändringar på marknaden för utrustning till mobiltelefonisystemLind, Rutger, Törnblad, Johan January 2002 (has links)
Background: Forecasting is an instrument that the managers rely upon for their anticipations of the future. Subcontractors control their operations according to the forecast volumes provided by the telecom mobile network equipment suppliers. The information in the forecasts is however not sufficient. Purpose: The purpose of this thesis is to identify and test relevant and available market indicators for prediction of future demand fluctuations on the telecom mobile network equipment market. Realisation: During a number of interviews, factors that are driving the network equipment market were clarified. The aim of this part was to identify possible market indicators. Hypotheses were set up to test the chosen indicators. In the second part, the indicators were tested statistically. Finally, the theoretical and logical support of the results was discussed. Result: To predict future movements in network equipment demand, the market indicators should focus on the telecom mobile operators, and their ability, need, and willingness to make new investments. The market indicators proven to be of most importance after the regression analyses were long-term market interest rates and telecom corporate bond indices.
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