[EN] Precise Point Positioning (PPP) method involves an absolute positioning technique from a single receiver with GNSS (Global Navigation Satellite Systems). Its theoretical basis consists of solving the position with observations using a single receiver, with clock and orbit state models, among other products. The main advance concerning the current differential technique is that differential or relative positioning uses the double-differences solution that requires, at least, two receivers to get a precise position or a receiver connected to a network of reference stations. However, until recently, and from a practical point of view, a precise absolute positioning with centimeter accuracy with a single GNSS receiver was considered unfeasible. The reason was the difficulty in cancellation of errors and the ambiguity resolution. The main factor that limits Precise Point Positioning (PPP) accuracy is the dependence on external information, which models the error sources, that is to say: the performance of the orbit and clock products, the quality of the observations, and the effects of the un-modeled or un-calibrated error sources. Precise ionospheric corrections and troposphere state models are also essential in order to improve positioning at centimeter level. Furthermore, in real-time PPP precise streams of products and state models are needed, and they must meet certain requirements of latency and continuous availability. In the case study of real-time positioning, the PPP technique is very sensible to gaps and outliers in the reception of the products and fluctuations in the constellation, producing lost of convergence, delay in initialization and a lack of accuracy in the results. Nowadays, this situation is changing, but it needs to evolve even more, because the real-time determination and the performance of the orbital parameters, clock states or other modeled errors of the GNSS satellites and signals, are still in a stage of improvement by the International GNSS Service, by the Analysis Centers and by researches all around the world. Therefore, the objective of this investigation was the study of Precise Point Positioning technique applied to the real-time case study, considering the performance of the available products in several sceneries and environments. The study focused on its application and how to improve limitations in the performance. The main tasks developed are: -A preliminary study of the multi - constellation context, the state of the art of Precise Point Positioning technique and modeling error sources, (chapters 1 and 2). -The review of the emission of the state models into a standard format and the discussion of the limitations in the alternatives in the generation of the models, (chapters 3 and 4). -The analysis of the optimization of this method with the development of new constellations, by means of the test of new products, and multiple simultaneous observations performed, (chapter 6). -To explore the possibilities of real-time recovering of integer ambiguities for PPP and the impact in the performance, providing practical demonstrations with experimental and standardized approaches, (chapter 7). -To study tactics to provide combined products in quasi-real time and real-time latency, (chapter 8), and in a regional or continental frame, with own applied solutions, (chapter 9). -The design and development of processing and analysis tools, (chapter 5), monitoring and distribution of results with the real-time PPP method, (chapter 10), and the study of potential applications, (chapter 11). / [ES] El método Precise Point Positioning, (PPP), consiste en una técnica de posicionamiento absoluto con un solo receptor GNSS (Global Navigation Satellite Systems). Su fundamento teórico se basa en resolver la posición con las observaciones de un único equipo, utilizando correcciones de osciladores y de órbitas de satélites, entre otros modelos. La potencia del método con respecto a la técnica diferencial reside en que el posicionamiento diferencial o relativo utiliza la solución de dobles diferencias que requiere, al menos, dos receptores para obtener una posición precisa o un receptor conectado a una red de estaciones de referencia. Sin embargo hasta hace poco y a efectos prácticos, un posicionamiento absoluto con precisión de centímetros con un solo equipo se ha considerado irrealizable. El motivo reside en la dificultad de la cancelación de errores y de obtener la resolución de ambigüedades enteras. El principal factor que limita, por tanto, el posicionamiento absoluto preciso es la dependencia de productos externos que modelen las fuentes de error, es decir: el rendimiento de los modelos de órbitas y relojes, la calidad de las observaciones, y los errores no modelados o no calibrados. Las correcciones ionosféricas y modelos de estado de la troposfera también son esenciales para alcanzar precisiones a nivel del centímetro. Por otro lado, si se trabaja con la técnica PPP en tiempo real, se necesita productos y modelos de estado recibidos continuamente a través de paquetes de datos por Internet, que deben cumplir con ciertos requisitos de latencia y disponibilidad continua. En el caso de estudio de posicionamiento en tiempo real, la técnica PPP es además muy sensible a las anomalías y las pérdidas en la recepción de los productos, y a las fluctuaciones de la constelación, produciendo pérdidas de convergencia, retrasos en la inicialización, y falta de continuidad y exactitud en los resultados. En este momento esta situación está experimentando grandes cambios, pero necesita evolucionar aún más, ya que la determinación en tiempo real y el rendimiento de los parámetros orbitales, estados de reloj u otros modelos de error de los satélites GNSS y sus señales, se encuentra todavía en fase de mejora por parte del International GNSS Service, por parte de los Centros de Análisis y por parte de investigadores de todo el mundo. Por lo tanto, el objetivo de este trabajo ha sido el estudio de la técnica de posicionamiento Precise Point Positioning enfocada al caso de tiempo real, en base al rendimiento de los productos disponibles en varios escenarios y entornos. El estudio se centró en su aplicación y en la implementación de soluciones para mejorar sus limitaciones. Las principales tareas desarrolladas son: -Un estudio preliminar del entorno multi-constelación, del estado del arte de la técnica Precise Point Positioning, así como de los errores a modelar, (capítulos 1 y 2). -La supervisión de la emisión de modelos en un formato estándar, y la discusión de las limitaciones existentes en las alternativas para su generación, (capítulos 3 y 4). -El análisis de la optimización de este método con el desarrollo de nuevas constelaciones, a través de la evaluación de nuevos productos y sesiones simultáneas de observación, (capítulo 6). -La exploración de las posibilidades de recuperación de la naturaleza entera de las ambigüedades y su repercusión en términos de rendimiento, proporcionando demostraciones reales, con aproximaciones experimentales y estandarizadas, (capítulo 7). -El estudio de las tácticas para proporcionar productos combinados robustos en tiempo quasi-real y real, (capítulo 8), y en un marco regional o continental, (capítulo 9), con soluciones propias aplicadas. -El diseño y desarrollo de herramientas de cálculo y apoyo, (capítulo 5), de monitorización y distribución de resultados procedentes de PPP en tiempo real, (capítulo 10), y el e / [CAT] El mètode Precise Point Positioning, (PPP), consisteix en una tècnica de posicionament absolut amb un sol receptor GNSS (Global Navigation Satellite Systems). El seu fonament teòric consisteix a resoldre la posició amb observacions d'un únic equip utilitzant correccions d'oscil¿ladors i d'òrbites de satèl¿lits, entre altres models. La potència del mètode respecte a la tècnica diferencial és que el posicionament diferencial o relatiu utilitza la solució de dobles diferències que requereix, almenys, dos receptors per a obtenir una posició precisa o un receptor connectat a una xarxa d'estacions de referència. No obstant això, fins fa poc i a efectes pràctics, un posicionament absolut amb precisió de centímetres amb un sol equip GNSS s'ha estat considerant irrealitzable. El motiu es troba en la dificultat de la cancel¿lació d'errors i d'obtenir la resolució d'ambigüitats senceres. El principal factor que limita, per tant, el posicionament absolut precís és la dependència de productes externs que modelen les fonts d'error, es a dir: el rendiment dels models d'òrbites i oscil¿ladors, la qualitat de les observacions, i els errors no modelats o no calibrats. Les correccions ionosfèriques i models d'estat de la troposfera també són essencials per a aconseguir precisions a nivell del centímetre amb un equip. D'altra banda, si es treballa amb la tècnica PPP en temps real, es necessita productes i models d'estat rebuts contínuament a través de paquets de dades per Internet, que han de complir amb certs requisits de latència i disponibilitat contínua. En el cas d'estudi de posicionament en temps real, la tècnica PPP és a més molt sensible a les anomalies i les pèrdues en la recepció dels productes, i a les fluctuacions de la constel¿lació, produint pèrdues de convergència, retards en la inicialització i falta de continuïtat i exactitud en els resultats. En aquest moment aquesta situació està experimentant grans canvis, però necessita evolucionar encara més, ja que la determinació en temps real i el rendiment dels paràmetres orbitals, els estats de rellotge o altres models d'error dels satèl¿lits GNSS i els seus senyals, es troben encara en fase de millora per part de l'International GNSS Service, per part dels Centres d'Anàlisi i per part d'investigadors de tot el món. Per tant, l'objectiu d'aquest treball ha consistit en l'estudi de la tècnica Precise Point Positioning enfocat al cas de temps real, fonamentat amb el rendiment dels productes disponibles a diversos escenaris i entorns. L'estudi es va centrar en la seva aplicació i en la implementació de solucions per millorar les limitacions en la seua productivitat. Les principals tasques desenvolupades són: -Un estudi preliminar de l'entorn multi-constel¿lació, l'estat de l'art de la tècnica Precise Point Positioning, així com dels errors a modelar, (capítols 1 i 2). -La supervisió de l'emissió de models amb un format estàndard, i la discussió de les limitacions en les alternatives a la generació de models, (capítols 3 i 4). -Anàlisi de l'optimització d'aquest mètode amb el desenvolupament de noves constel¿lacions, amb l'avaluació de nous productes i múltiples sessions simultànies d'observació, (capítol 6). -L'exploració de les possibilitats de recuperació de la naturalesa sencera de les ambigüitats i la seva repercussió en termes de rendiment, proporcionant demostracions reals, utilitzant aproximacions experimentals i estandarditzades, (capítol 7). -L'estudi de les tàctiques per a proporcionar productes combinats robustos en temps quasi-real i en temps real, (capítol 8), i en un marc regional o continental, amb solucions pròpies aplicades, (capítol 9). -El disseny i desenvolupament d'eines de càlcul i suport (capítol 5), de monitorització i distribució de resultats aplicats al cas de PPP en temps real, (capítol 10), i l'estudi de potencials aplicacions de la tècnica, (capí / Capilla Romá, R. (2015). Aportación al estudio de la capacidad de los modelos conceptuales en posicionamiento absoluto preciso (Precise Point Positioning) para tiempo real a través del análisis del rendimiento de productos y prototipos en un escenario multi-constelación GNSS [Tesis doctoral]. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/52814 / TESIS

Dagens företag vill ge anställda möjlighet att jobba hemifrån eller på resande fot. En vanlig lösning för att möjliggöra detta är virtual private network (VPN). VPN ger en användare tillgång till interna resurser på företaget från ett externt nät, exempelvis via Internet. Detta gör att användare kan komma åt de interna resurserna på ett säkert sätt. Vilken VPN-teknik är då att föredra för att få en så snabb, säker och pålitlig anslutning som möjligt? Detta examensarbete tar upp olika VPN-tekniker. Vi beskriver vanliga VPN-protokoll som L2TP, IPSec och PPTP. Hur användare autentiseras på ett säkert och smidigt sätt samt metoder att göra sin VPN-anslutning säker. Vi redovisar också den lösning vi har implementerat hos Confidence, för vilka arbetet utfördes. Problemen med att använda de produkter som redan fanns på företaget beskrivs. Förslag på lösningar ges för att lösa dessa problem i framtida arbeten. / Companies of today want to give their employees the opportunity to work from home or while they travel. A common solution to accomplish this is to implement a VPN over top of the existing network. Using VPN gives the employees access to the company’s local area network from outside, via the internet. The VPN provides a secure channel for these employees to connect to the local services attached to the company’s network that they need to reach. Which VPN technology is most suitable to deliver a secure, fast, and reliable connection to theses employees? In this thesis examines we are taking a closer look at different VPN solutions. We describe different VPN-protocols like L2TP, IPSec and PPTP. How to authenticate users in a secure and flexible way and also methods used to make the VPN-connection secure. Lastly we will show the solution we have implemented at the company Confidence, for whom we made the solution. The difficulties in using existing products with the company’s infrastructure are described. Suggestions are offered for future work to address these problems.

Kuwait is planning for huge infrastructure and development projects through long term strategies and visions from 2007 until 2035 to overcome the needs for the welfare housing and to move the country to be the region’s top commercial and financial hub. These goals wouldn’t be achieved without having a strong partner (private sector) to drive the economy by participating in construction mega projects. Public-private partnership (PPP) is the framework which engages both parties to successfully achieve long term plans to deliver what the country and citizens need. To attract the private sector to participate and provide the services needed with the expected high qualities and techniques, the public sector needs to improve the environment to facilitate PPP implementation. This research investigates the existence of critical success factors of PPP project in construction sector of Kuwait: Effective procurement, Project implementability, Available financial market, Government guarantee and Favorable economic conditions and give recommendations to focus on improving them to achieve successful PPP projects.

Education in South Africa is a key concern because the South African education system is underperforming compared to many other developing countries despite the large capital investment made by the South African government and its private sector. South African children are routinely underachieving and rate not only among the worst in the world, but often among the worst in the Southern African region and in Africa as a whole. Therefore, the aim of this study was to explore whether Public-Private Partnership (PPP) is a suitable model for improving the quality of education in South African rural communities.The objective of the study was answered in a two-phase approach. The first phase developed an understanding of the challenges that prevents the delivery of quality education in South African rural communities with experts in education. The second phase determined the suitability of PPP to improve the quality of education in South African rural communities and the critical success factors for implementing PPP in education from interviews with PPP practitioners.The findings of the study revealed that PPP is a suitable model to improve the quality of education in South African communities and a PPP framework was proposed by the researcher that indicates the benefits of implementing PPP, the critical success factors of PPP and the barriers of PPP in education. The study also highlighted conditions that must be met to achieve quality education in South African rural communities through PPPs.The research concludes by making recommendations to both the government and the public sector in light of the findings of this research. Limitations for the study were highlighted and other variables to be researched that are important to further understanding of PPP as a model to improve the quality of education in South African rural communities were suggested. / Dissertation (MBA)--University of Pretoria, 2012. / Gordon Institute of Business Science (GIBS) / unrestricted

Strengthening health care systems in government meant cost containment and improved equity. Escalating costs and poorly constructed strategies are weakening the efficiency and effectiveness of service delivery in health care. This has a negative impact on value creation and internal processes as critical elements such as human capital, information and organisational capital are not aligned with strategies and roll-out plans for HIV/Aids interventions. This research study therefore questioned the extent to which these strategies have impacted on the roll-out plans for HIV/Aids interventions, and investigated if the utilisation of public-private partnerships (PPP) resulted in applying fiscal reponsible mechanisms in health care reforms (effectively, efficiently, economically and equitably (4Es)). Trends in the new public management (NPM) movement inspired a shift towards business-like reforms and saw PPP as a mechanism that improved efficiency and effectiveness in service delivery as it offered the promise to strengthen the capacity of government policy. The study aimed to put forward value-creating strategies and develop a best practice model that strengthened government’s policy capacity by providing efficient, effective, economical and quitable service in health care and thereby improving strategies that impact on the roll-out plans for HIV/Aids. This comparative study comprised four international case studies (developed and developing countries) which presented benchmarks against which the performance of the national case study was measured. A better understanding of the influence which different ideologies had on the architecture of international and global governance structures was gained as it highlighted and compared the key issues that influenced strategies for HIV/Aids intervention between the developed and developing countries. Results of the study indicated that there are conflicting views between government departments in how to achieve value-for-money outcomes and their application of risk allocation. The conflicting views widened the gap between public and private governance structures and relations. The focus of the PPP definition as applied in the national context of health care is not percieved as being health-specific or effective as it excludes some forms of interactions occurring in the health sector. PPP goals emphasised efficiency, affordability and value-for-money approaches, while health care goals emphasised the interest of the “patient” and public health. / Thesis (PhD (Public Affairs))--University of Pretoria, 2007. / School of Public Management and Administration (SPMA) / unrestricted

Local public agencies turn to public-private partnerships (PPPs) to allow greater participation by private firms in delivering public services. In the last 25 years, private organizations had been reluctant to form PPPs with local government agencies because of the complex procurement processes and the bureaucratic business environment. Guided by the decision theory and complex adaptive systems theory, the purpose of this multiple case study was to identify what information leaders within third-party administrators (TPAs) need regarding the contracting process in the formation of PPPs. The data collection process consisted of face-to-face interviews with 4 executive leaders of 3 Wisconsin state licensed TPAs and examination of contracts and plan service agreements (PSAs) between TPAs and local government agencies. Dada was analyzed using the Yin 5-step data analysis method and cross-case analysis. The results indicated that TPA leaders must understand collaborative leadership, key players, roles and responsibilities, and specialized services in the formation of a PPP; change and transfer of controlling interest, and understanding the strengths and weakness of contract provisions are complex business systems that influence the decision to form a PPP; ERISA and compliance with applicable federal and state laws are critical contract stipulations to consider in the formation of PPPs; that market assessment, health care reform, and transparency between private and public partners are critical in the formation of PPPs. The implications for social change include new insights for PPP leaders that may enhance the effectiveness of social services and save taxpayers' money.

Cette thèse se penche sur les contributions de la formation enseignante partiellement à distance et à l’aide du mobile, comment celles-ci évoluent et quels facteurs l’influencent. Les deux premiers chapitres discutent le contexte de recherche de cette thèse. Ils montrent le lien étroit entre l'évolution des politiques éducatives, les stratégies de recrutement des enseignants et la nécessité d'une formation à la fois réaliste et qualitative des enseignants. Après un rappel de la croissance exceptionnelle du secteur des infrastructures mobiles, la revue de littérature expose les résultats de recherches récentes de l’utilisation du mobile pour la formation des maitres à distance. Le contexte de la recherche montre qu'il y a un manque de recherche sur les contributions à moyen terme de la formation assistée par mobile et que cela est étroitement lié à l'approche ‘court-termiste’ des projets pilotes. C’est pour cela que quatre études (chapitres 5 à 7) cherchent à analyser les contributions dans une perspective à la fois multidimensionnelle et longitudinale. La première étude (chapitre 5) analyse d'un point de vue exploratoire les contributions rapportées et observées de la formation IFADEM chez les anciens participants. Il révèle entre autres que les contributions de soutien sont principalement reposent sur le mobile et sont intégrées dans la sphère professionnelle et privée. Ces usages durables sont motivés par une motivation intrinsèque et perdurent grâce à une forte expérience d'appropriation collective qui a servi de « coup d'envoi» aux nouvelles pratiques. Compte tenu de la domination des usages mobiles, la deuxième étude (chapitre 6) se concentre sur les communications mobiles. Elle confirme la pérennité des communications téléphoniques malgré la fin des stimuli organisationnels ou financiers externes, et montre également comment ces communications durables par téléphone reflètent l'appropriation permanente du mobile pour le travail et le privé. Ce chapitre permet en outre d'identifier les facteurs clés qui permettent ce processus d'appropriation en premier lieu. En plus de cette identification de ce que l'on peut appeler des « facteurs de risque et de réussite» pour des contributions mobiles de formation continue des enseignants, elle révèle également l'importance de la communication continue entre pairs parmi les anciens participants. Par la suite, la troisième étude (chapitre 7) analyse les structures et les processus de ces connexions mobiles prises en charge. Comme l'ont indiqué les répondants interrogés pour la première étude, la présence d'un réseau d'enseignants collaboratif stable pourrait être confirmée. Son analyse permet de qualifier les liens entre les anciens participants, qui sont à la fois de nature instrumentale et expressive. Les motivations multiples pour faire partie de ce réseau contribuent à sa durabilité et à son autonomie plus de deux ans après la fin de la formation, durabilité qui est renforcées par la présence de leaders qui assurent la circulation de l'information interne et externe. Globalement, il fournit une perspective supplémentaire sur l'importance et les résultats d'un processus d'appropriation collective. Enfin, la quatrième étude (chapitre 8) change de perspective, abordant la question des contributions à moyen terme et des facteurs pertinents pour la durabilité à travers l'organisation des parties prenantes, à savoir ceux qui financent, organisent, conçoivent et évaluent la formation mobile des enseignants. Cette étude indique non seulement que les acteurs se perçoivent comme faisant partie d'un système soumis à une pression politique considérable et exigent que leurs activités soient fortement limitées, ce qui conduit à une perspective à court terme sur les facteurs de succès. / This dissertation analyzes the contributions of mobile supported teacher training, how these evolve and which factors take influence on this evolution. The first two chapters expose the close link between the evolution of education policies, teacher recruitment strategies and the need for a both realistic and qualitative teacher training. After a recall of the exceptional growth of mobile infrastructure sector, the use of distance and notably mobile supported teacher training is discussed. The research context shows that there is lack of research on the medium-term contributions of mobile supported teacher training and provides strong indicators that this issue is closely related to the overall short-term approach of pilot projects. Therefore, four studies (chapter 5 to 7) seek to analyze contributions through a both multidimensional and longitudinal perspective. The first study (Chapter 5), analyzes from an exploratory perspective the reported and observed contributions of the IFADEM training among former participants. It reveals amongst others that the sustaining contributions are mostly mobile phone supported and well embedded in the professional and private sphere of former individuals. These sustainable usages are driven by intrinsic motivation, and sustain because of a strong collective appropriation experience that acted as ‘kick off’ phase for new practices. Given the domination of mobile usages, the second study (chapter 6) focuses on mobile communications, one of the reported key contributions of the IFADEM training. It confirms the sustainability of phone communications despite the end of external organizational or financial stimuli, and shows also how phone these sustainable communications reflect the ongoing appropriation of mobile for work and private matters. This chapter allows further to identify those key factors that allow for this appropriation process to happen in the first place. Besides this identification of what can be called ‘risk and success factors’ for sustainable mobile teacher training contributions, it reveals also the importance of ongoing peer to peer communication among former participants. Subsequently, the third study (Chapter 7) analyzes structures and processes of these mobile supported connections. As indicated by respondents interviewed for the first study, the presence of a stable, collaborative teacher network could be confirmed. Its analysis allows qualifying the ties among former participants, which are both of instrumental and expressive nature. Multiple motivations to be part of this network contribute to its sustainability and autonomy over two years after the end of the training, strengthened by the presence of leaders who ensure internal and external information flow. Overall, it provides an additional perspective on the importance and outcomes of a collective appropriation process. Finally, the fourth study (Chapter 8) shifts perspectives, approaching the question of medium-term contributions and pertaining factors for sustainability through the lens of organizing stakeholders, i.e. those who fund, organize, design and evaluate mobile teacher training. This study indicates not only that actors perceive themselves as part of a system with considerable political pressure and demands that constraint significantly their activities, leading to a short term perspective on success factors.It reveals also that projects partners are considered simultaneously as goal and obstacle. Their descriptions indicate an often difficult and sometimes patronizing relationship, which occupy a central place in projects preoccupations’. Actors depict also pilot projects as organizational and political instrument. The collision of a normative discourse of high moral value with a technical and organization oriented discourse is one of the striking results of this study.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第17870号 / 工博第3779号 / 新制||工||1578(附属図書館) / 30690 / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 小林 潔司, 教授 河野 広隆, 准教授 松島 格也 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20350号 / 工博第4287号 / 新制||工||1664(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 小林 潔司, 教授 大津 宏康, 准教授 松島 格也 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

京都大学 / 新制・論文博士 / 博士(工学) / 乙第13563号 / 論工博第4210号 / 新制||工||1986(附属図書館) / (主査)教授 山田 忠史, 教授 宇野 伸宏, 教授 須崎 純一 / 学位規則第4条第2項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM