The wide-spread coverage and ubiquitous presence of mobile networks has propelled the usage and adoption of mobile phones to an unprecedented level around the globe. The computing capabilities of these mobile phones have improved considerably, supporting a vast range of third party applications. Simultaneously, Peer-to-Peer (P2P) overlay networks have experienced a tremendous growth in terms of usage as well as popularity in recent years particularly in fixed wired networks. In particular, Distributed Hash Table (DHT) based Structured P2P overlay networks offer major advantages to users of mobile devices and networks such as scalable, fault tolerant and self-managing infrastructure which does not exhibit single points of failure. Integrating P2P overlays on the mobile network seems a logical progression; considering the popularities of both technologies. However, it imposes several challenges that need to be handled, such as the limited hardware capabilities of mobile phones and churn (i.e. the frequent join and leave of nodes within a network) intensive mobile networks offering limited yet expensive bandwidth availability. This thesis investigates the feasibility of extending P2P to mobile networks so that users can take advantage of both these technologies: P2P and mobile networks. This thesis utilises OverSim, a P2P simulator, to experiment with the performance of various P2P overlays, considering high churn and bandwidth consumption which are the two most crucial constraints of mobile networks. The experiment results show that Kademlia and EpiChord are the two most appropriate P2P overlays that could be implemented in mobile networks. Furthermore, Network Address Translation (NAT) is a major barrier to the adoption of P2P overlays in mobile networks. Integrating NAT traversal approaches with P2P overlays is a crucial step for P2P overlays to operate successfully on mobile networks. This thesis presents a general approach of NAT traversal for ring based overlays without the use of a single dedicated server which is then implemented in OverSim. Several experiments have been performed under NATs to determine the suitability of the chosen P2P overlays under NATed environments. The results show that the performance of these overlays is comparable in terms of successful lookups in both NATed and non-NATed environments; with Kademlia and EpiChord exhibiting the best performance. The presence of NATs and also the level of churn in a network influence the routing techniques used in P2P overlays. Recursive routing is more resilient to IP connectivity restrictions posed by NATs but not very robust in high churn environments, whereas iterative routing is more suitable to high churn networks, but difficult to use in NATed environments. Kademlia supports both these routing schemes whereas EpiChord only supports the iterating routing. This undermines the usefulness of EpiChord in NATed environments. In order to harness the advantages of both routing schemes, this thesis presents an adaptive routing scheme, called Churn Aware Routing Protocol (ChARP), combining recursive and iterative lookups where nodes can switch between recursive and iterative routing depending on their lifetimes. The proposed approach has been implemented in OverSim and several experiments have been carried out. The experiment results indicate an improved performance which in turn validates the applicability and suitability of ChARP in NATed environments.

The main aim of this master's thesis is to implement a common, secure and peer-to-peer communication system. The system has ability to automatically establish and run a secure end-to-end connection. It has this ability even if a network address translator is in the way to the destination system, without need of any explicit configuration of this translator. The security procedures of this system are in a transparent manner masked from individual applications, which had to solve this challenge in their own way. A responsibility for a security is delegate to an application-independent subsystem working within the core of an operating system. The security of this subsystem is based on capturing the outbound and inbound IP packets and their authentication and encryption. The system was successfully implemented in MS Windows XP operating system, in programming language C++. Transfer rate of communication tunnel in different network bandwidth speeds was measured. Result shows, that in the case of use the system on standard PC sold nowadays is practically no decrease of the transfer rate in comparison to a common channel.

This master’s thesis deals with jet streams. The exploration part describes conditions of jet stream formation, its characteristics, classification on the geographical basis and phenomena attendant on the jet streams. It also contains a description of jet stream measurement methods and methods of its interpretation in aeronautical meteorological charts. Organization of aeronautical traffic in the north Atlantic region within reach of the jet streams is further described. Practical part of this thesis contains author’s own research which compares time and economical profitability of transatlantic flights planned according to the jet streams. The principle of this evaluation was based on assessment of real flights and flights via shortest possible routes. It was proven, that profits mentioned above are gained only in the oceanic parts of flights.

Nowdays, when we are running out of public IPv4 addresses, we rely on techniques that at least postpone their complete exhaustion. One of these techniques is a network address translation (NAT). Internet providers require the highest possible bandwidth from devices that perform this task. This thesis compares NAT DPDK, built on top of DPDK framework, with freely available alternatives. This work also extends NAT DPDK with Application-Level Gateway support.

Die vorliegende Arbeit entwickelt und implementiert ein System für die Bereitstellung von Internet-Diensten an öffentlichen Orten. Besonderer Wert wurde auf eine einfache Handhabung für den Nutzer, eine breite Unterstützung von Klienten und ein breites Spektrum möglicher Privilegien (von der vollen Internetkonnektivität bis zu einer Art Infoterminalstatus) gelegt.

This thesis investigates designing and implementing a peer-to-peer (P2P) networking frameworkfor Unity, a popular game engine, intending to offer a scalable and efficient solution forconstructing networked multiplayer games. The research covers an analysis of a P2P networkarchitecture, transport layer protocols, challenges in NAT traversal, and peer list management.A framework is proposed, incorporating NAT traversal, remote procedural calls (RPC), synchronization variables (SyncVar), interest management (IM), and a lobby system. The framework’sperformance is evaluated through integration, network, and game performance tests. Resultsdemonstrate the framework’s capacity to accommodate up to 50 players, with a theoreticalmaximum of 200 players, but further optimization techniques could increase this limit. IMsolutions are suggested to improve scalability, rendering the framework a more viable optionfor MMOGs. Additionally, this thesis seeks to contribute to comprehending P2P networkingframework design and implementation for Unity while emphasizing potential directions forfuture research and how they should be optimized / Denna uppsats undersöker design och implementering av ett peer-to-peer (P2P) nätverksramverk för Unity, en populär spelmotor, med målet att erbjuda en skalbar och effektiv lösning för att bygga nätverksbaserade flerspelarspel. Uppsatsen omfattar en analys av P2P-nätverksarkitektur, transportlagerprotokoll, utmaningar vid NAT-Travesering och hantering av peerlistor. Ett ramverk som inkluderar NAT-Travesering, fjärrproceduranrop (RPC), synkroniseringsvariabler (SyncVar), Interest Management (IM) och ett lobby-system föreslås. Ramverkets prestanda utvärderas genom integrationstester, nätverksprestandatester och spel-prestandatester. Resultaten visar att ramverket kan hantera upp till 50 spelare, med en teoretisk maximal kapacitet på 200 spelare, men ytterligare optimiserings tekniker kan öka denna gränsen. IM-lösningar föreslås för att förbättra skalbarheten, vilket gör ramverket till ett bättre alternativ för MMOG. Dessutom syftar denna uppsats till att bidra till förståelsen för design och implementering av P2P-nätverksramverk för Unity, samtidigt som den betonar potentiella riktningar för framtida forskning och hur dessa ska kunna optimeras.

Den här rapporten grundar sig i problematiken med att kombinera TCP/IPv4 ochTCP/IPv6 med varandra. De två protokollen är inte kompatibla att skicka paket mellansig och bara delar av internet använder sig av, eller har stöd för, det nyare protokolletIPv6. På grund av att de publika IPv4-adresserna är slut i världen så måsteförr eller senare en fullständig migrering ske på internet. Fram till dess behövs dockmigreringsmetoder som kan hantera både de äldre och de nyare TCP/IP-protokolletsimultant.I rapporten kommer olika migreringsmetoder plockas fram där fokus ligger påkomplexitet, alltså tidsåtgång för implementering. Metoderna som presenteras utgören laboration där testpersoner har fått utföra simulerade migreringar med de olikateknikerna för att få fram tidsdata. Med hjälp av tidsdatan presenteras sedan denminst komplexa migreringsmetoden. En minimalt komplex metod kan hjälpa bådeprivatpersoner och företag kopplade till internet att migrera från IPv4 till IPv6 på ettsmidigare sätt.Migreringslösningarna i den här rapporten riktar sig dock främst till en målgruppav medelstora företag som vill använd sig av IPv6 men samtidigt ha möjlighet attvara anslutna till internet.Resultatet visade att med hjälp av en teknik kallad Dual Stacking kunde bådeIPv4 och IPv6 användas på ett nätverk simultant. Våra testpersoner pekade också påatt denna teknik är den minst komplexa, alltså lättast att implementera och förstå.Resultatet av rapporten kan göra att fler vågar använda sig av IPv6 och när dagenkommer då internet går över till IPv6 så kommer dessa företag ligga i framkant ochvara väl förberedda. / This report is based on the problem of combining TCP/IPv4 and TCP/IPv6 with eachother. The two protocols are not compatible to send packets between themselves andonly parts of the Internet make use of, or supports, the newer IPv6 protocol. Due tothe shortage of public IPv4 addresses in the world we need to, sooner or later, makea complete migration from IPv4 to IPv6 over the Internet. However, until needed,we can make use of migration methods that can handle both the older and the newerTCP/IP protocols simultaneously.In the report, various migration techniques are evaluated with the main focusbeing complexity, as in: the time it takes to implement the solution. The methodpresented constitute a laboratory task where the test persons performs simulated migrationswith the different techniques to get a time data. With the help of time datathe least complex migration method is later presented. A minimally complex methodcan help both individuals and companies connected to the Internet to migrate fromIPv4 to IPv6 in a smoother manner.Migration solutions in this report are mainly addressed to a target group of mediumsizedcompanies that want to use the IPv6-protocol but at the same time want to havethe opportunity to be connected to the Internet.The results showed that by using a technique called Dual Stacking, both IPv4 andIPv6 can be used on a network simultaneously. Our testers also pointed out that thistechnique is the least complex, therefore the easiest to implement and understand.The outcome of the report might result in more companies daring to use IPv6, andwhen the day comes when the Internet completely migrates to IPv6 these companieswill be in the forefront and well prepared.

Submitted by Cássio da Cruz Nogueira (cassionogueirakk@gmail.com) on 2017-09-11T18:35:59Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_SoroconversoesVirusHepatite.pdf: 4085875 bytes, checksum: 4b44b45a4f9ce1c7775082aeab35d4c9 (MD5) / Approved for entry into archive by Irvana Coutinho (irvana@ufpa.br) on 2017-09-20T12:10:15Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_SoroconversoesVirusHepatite.pdf: 4085875 bytes, checksum: 4b44b45a4f9ce1c7775082aeab35d4c9 (MD5) / Made available in DSpace on 2017-09-20T12:10:15Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_SoroconversoesVirusHepatite.pdf: 4085875 bytes, checksum: 4b44b45a4f9ce1c7775082aeab35d4c9 (MD5) Previous issue date: 2014 / O Vírus da hepatite C na atualidade é um dos principais causadores de cirrose hepática e de hepatocarcinoma, também constitui-se como um dos principais motivos de inaptidão para doação de sangue entre a população. A hepatite C apresenta-se como uma das principais doenças infectocontagiosa no cenário mundial. O objetivo deste trabalho foi realizar um estudo comparativo e uma análise entre as metodologias de triagem para o HCV em doadores de sangue da Fundação Centro de Hematologia e Hemoterapia do Pará (HEMOPA) antes e após a implantação do teste NAT. A metodologia utilizada teve uma abordagem quantitativa, prospectivo e com objetivos gerais de natureza descritiva, e utilizou procedimento técnico documental, com registros escritos pré-existentes na Fundação HEMOPA. Ocorreram 125 soroconversões para HCV diagnosticadas pelo teste ELISA e 176 diagnosticadas pelo NAT associado à Quimiluminescência, totalizando 301 soroconversões no período de abril de 2013 a setembro de 2014. Observou-se no estudo uma maior ocorrência da taxa de soroconversões quando utilizava-se a técnica de biologia molecular associado a um teste imunológico em detrimento a metodologia ELISA. No estudo, a maioria dos sujeitos era do sexo masculino, com idade inferior a 35 anos, solteiros e possuíam ensino médio completo; observou-se também que dentre os fatores de risco estudados o item “Cirurgia” mostrou-se estatisticamente significante. Conclui-se que há um relevante indício de que a utilização dos testes moleculares e imunológicos combinados incrementa a segurança no processo de seleção de doadores de sangue. / The Hepatitis C virus is currently one of the main causes of hepatic cirrhosis and hepatocellular carcinoma; it also constitutes one of the main reasons of unsuitability for blood donation among the population. Hepatitis C presents itself as one of the main infectious diseases in the worldwide scenario. The aim of this work was to conduct a comparative study and a analysis of the methods of screening for HCV in blood donors of the Foundation Center of Hematology and Hemotherapy of Pará (HEMOPA) before and after the implementation of NAT test. The methodology used had a quantitative, prospective, with general objectives of descriptive nature approach, and used a technical procedure with pre-existent written registrations in HEMOPA Foundation. There were 125 seroconversions to HCV diagnosed by ELISA, and 176 diagnosed by NAT, associated with chemiluminescence, totalizing 301 seroconversions from April 2013 to September 2014. It was observed in the study that there was a higher rate of seroconversions when the technique of molecular biology was used, which is associated with an immunological test, instead of the ELISA methodology. In the study most people were male, under 35 years old, unmarried, and had complete high school level. It was observed that among the risk factors studied, the “Surgery” one was statistically significant. We concluded that there is an important clue that the combined use of molecular and immunological tests improves security in the process of blood donors selection.

<p>The objective of this thesis is to design and implement a small scaleInternet Service Provider (ISP) for the NetCenter sub department atMälardalen University. The ISP is intended to give NetCenter a networkseparate from the University’s network, providing them with a moreflexible environment for lab purposes. This will give their students anopportunity to experience a larger backbone with Internet accessibility,which has not been previously available. At the same time it will place theteachers in control of the network in the NetCenter lab premises.The network is designed with a layered approach including an Internetaccess layer, a larger core segment and a distribution layer with aseparated lab network. It also incorporates both a public and a privateserver network, housing servers running e.g. Windows Active Directory,external DNS services, monitoring tools and logging applications. TheInternet access is achieved by peering with SUNET providing a full BGPfeed.This thesis report presents methods, implementations and results involvedin successfully creating the NetCenter ISP as both a lab network and anInternet provider with a few inevitable shortcomings; the most prominentbeing an incomplete Windows Domain setup.</p>

Malaria is a life–threatening disease caused by Plasmodium spp and causes over one million deaths annually. The complex life cycle of the malaria parasite offers several points of attack for the antimalarial drugs. The rapid spread of resistance against antimalarial drugs, especially chloroquine and pyrimethamine–sulphadoxine, emphasises the need for new alternatives or modification of existing drugs. Artemisinin–based combination therapies (ACT’s) with different targets prevent or delay the development of drug resistance and therefore have been adopted as first–line therapy by all endemic countries. Proguanil–dapsone, an antifolate combination is more active than pyrimethamine–sulphadoxine and is being considered as an alternative to pyrimethamine–sulphadoxine. Artesunate–proguanil–dapsone is a new ACT that has wellmatched pharmacokinetics and is relatively rapidly eliminated; therefore there is a reduced risk of exposure to any single compound and potentially a decreasing risk of resistance. A few studies have been done on a triple fixed–dose combination therapy for malaria treatment and such a combination for artesunate, proguanil and dapsone are not currently investigated, manufactured or distributed. The aim of this study was to develop a triple fixed–dose combination for artesunate, proguanil and dapsone. The formulation was developed in three phases; basic formulation development, employing factorial design to obtain two possible optimised formulations and evaluating the optimised formulations. During the formulation development the most suitable manufacturing procedure and excipients were selected. A full 24 factorial design (four factors at two levels) was used to obtain the optimised formulations. As end–points to identify the optimised formulations, weight variation, friability, crushing strength and disintegration of the tablets, were used. Statistical analysis (one way ANOVA) was used to identify optimal formulations. To identify any interaction between the active pharmaceutical ingredients (API’s) and the API’s and excipients, differential scanning calorimetry was done. Flow properties of the powder mixtures (of the optimised formulations) were characterised by means of angle of repose; critical orifice diameter (COD); bulk density and tapped density; and flow rate. Tablets of the two optimised powder formulations were compressed. The tablets were evaluated and characterised in terms of weight variation, friability, crushing strength, disintegration and dissolution behaviour. Initial formulation development indicated that wet granulation was the most suitable manufacturing method. The results from the factorial design indicated that different amounts (% w/w) of the lubricant and binder as well as two different fillers influenced the weight variation, crushing strength and disintegration statistically significant. Two formulations containing two different fillers (microcrystalline cellulose or Avicel® PH 101, and lactose or Granulac® 200) were found to be within specifications and ideal for manufacturing. Tablets prepared from the FA formulation (formulation containing Avicel® PH 101) complied with the standards and guidelines for weight variation, friability, crushing strength and disintegration as set by the British Pharmacopoeia (BP). Tablets had an average crushing strength of 121.56 ± 0.022 N. Tablets disintegrated within 52.00 seconds and a maximum weight loss of 0.68% occurred during the friability test. Weight variation of the tablets prepared from the FG formulation (formulation containing Granulac® 200) complied with the standards. Average crushing strength was 91.99 ± 6.008 N and the tablets disintegrated within 140.00 seconds. Percentage friability (1.024%) did not comply with the guideline of a percentage friability of less than 1%, however, no cracked or broken tablets were seen. Dissolution showed that 98, 93 and 94% of artesunate, proguanil and dapsone were respectively released (of the label value) within 15 minutes for the FA formulations. Release of artesunate, proguanil and dapsone for the FG formulation was 62, 85 and 92% for the same time period. The release of the three API’s (the FG formulation) increased to 78, 89 and 92%, respectively, after 45 minutes. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2012.