Detta arbete beskriver en examensuppsats i datateknik på Linnéuniversitetet. Röntgenavdelningen på SUS, Skånes Universitetssjukhus i Lund, använder en lättviktig flyttbar röntgenmaskin som väger endast cirka 90 kg, för röntgenundersökningar ute på äldreboenden. Bilderna överförs till sjukhusets PACS när maskinen är tillbaka på sjukhuset, genom att man kopplar in Dragon via kabel till sjukhusets nätverk. Målsättningen är att förbättra den trådlösa kommunikationen som för närvarande är för långsam och opålitlig, så att bilderna kan överföras till sjukhusets PACS direkt efter undersökningen. I detta arbete beskrivs vilka alternativ som kan användas. Samt om de mobila bredbandstjänster som finns tillgängliga i Region Skåne är bra nog för att kunna användas för uppgiften. Slutsatsen är att ett 3G HSDPA/HSUPA abonnemang kan vara tillförlitligt nog. Framför allt om extra redundans tillförs med dubbla SIM-kort som använder separata nät och att signalen förstärks med antenn placerad utomhus på transportfordonet. Transportfordonet används som brygga mellan Wifi och mobilt nätverk. Röntgenmaskinen kommunicerar med transportfordonet via Wifi. För de fall Wifi inte fungerar på grund av byggnader och omgivande miljö arbetades ett reservalternativ fram. Jag har också undersökt och jämfört DICOM protokollet mot FTP. Detta för att se om DICOM har en overhead som skulle motivera användet av FTP istället för sändning av bilder. Resultatet av jämförelsen visade att DICOM har 5-10 % overhead jämfört med FTP. / This abstract describes a degree project in computer engineering at Linnaeus University. The Department of Radiology at SUS, Skåne University Hospital in Lund, is using a lightweight portable x-ray machine that weights about 90 kg, for radiography services in nursing homes for elders. The images are transferred to hospital PACS when the machine returns to the hospital, this is done with Dragon connecting to hospital network via wire. The goal is to improve the currently too slow and unreliable wireless communication, so the images can be transferred to hospital PACS directly after examination. This report describes what alternatives can be used and investigates whether the mobile broadband services currently available in Skåne County are good enough to be relied on for the task. The conclusion is that a 3G HSDPA/HSUPA subscription can be used reliably enough, if extra redundancy is added via dual SIM cards using separate mobile networks and the signal is strengthen by an antenna placed outdoors on the transport vehicle. The transport vehicle is used as a bridge between Wifi and mobile networks. The mobile x-ray machine communicates with the transport vehicle via Wifi. In those cases Wifi does not work due to difficult building environments, a backup solution was worked out to be used. I also investigated and compared the DICOM protocol against FTP. This was to find out if DICOM has an overhead that would motivate using FTP instead for the transmission of the images, the result of the comparison showed that DICOM has an 5-10 % overhead compared with FTP. / Mobil röntgen Skånes Universitetssjukhus Lund

隨著WiFi訊號在都市的涵蓋率逐漸普及，基於WiFi訊號強度值的定位方法逐漸發展。WiFi匹配定位(Matching Positioning)是透過參考點坐標與WiFi訊號強度(Received Signal Strength Indicator, RSSI)的蒐集，以最小二乘法(Least Squares, LS)計算RSSI模型參數；然後，利用模型參數與使用者位置的WiFi訊號強度，推估出使用者的位置。然而WiFi訊號強度容易受到環境因素影響，例如降雨、建物遮蔽、人群擾動等因素，皆會使訊號強度降低，若以受影響的訊號強度進行定位，將使定位成果與真實位置產生偏移。 為了降低訊號強度的錯誤造成定位結果的誤差，本研究嘗試透過具有穩健性的最小一乘法( Least Absolute Deviation, LAD)結合WiFi匹配定位，去克服WiFi訊號易受環境影響的特性，期以獲得較精確的WiFi定位成果。研究首先透過模擬資料的建立，測試不同粗差狀況最小一乘法WiFi匹配定位之表現，最後再以真實WiFi訊號進行匹配定位的演算，並比較最小一乘法WiFi匹配定位與最小二乘法WiFi匹配定位的成果差異，探討二種方法的特性。 根據本研究成果顯示，於模擬資料中，最小一乘法WiFi匹配定位相較於最小二乘法WiFi匹配定位，在面對參考點接收的AP訊號與檢核點接收的AP訊號強度含有粗差的情形皆能有較好的穩健性，且在參考點接收的AP訊號含有粗差的情況有良好的偵錯能力。而於真實環境之下，最小一乘法WiFi匹配定位之精度也較最小二乘法WiFi匹配定位具有穩健性；在室外資料的部份，最小一乘法WiFi匹配定位之精度為8.46公尺，最小二乘法WiFi匹配定位之精度為8.57公尺。在室內資料的部份，最小一乘法WiFi匹配定位之精度為2.20公尺，最小二乘法WiFi匹配定位之精度為2.41公尺。 / Because of the extensive coverage of WiFi signal, the positioning methods by the WiFi signal are proposed. WiFi Matching Positioning is a method of WiFi positioning. By collecting the WiFi signal strength and coordiates of reference points to calculate the signal strength transformation parameters, then, user’s location can be calculated with the LS (Least Squares). However, the WiFi signal strength is easily degraded by the environment. Using the degraded WiFi signal to positioning will produce wrong coordinates. Hence this research tries to use the robustness of LAD (Least Absolute Deviation) combining with WiFi Matching Positioning to overcome the sensibility of WiFi signal strength, expecting to make the result of WiFi positioning more reliable. At first, in order to test the ability of LAD, this research uses simulating data to add different kind of outliers in the database, and checks the performance of LAD WiFi Matching Positioning. Finally, this research uses real data to compare the difference between the results of LAD and LS WiFi Matching Positioning. In the simulating data, the test result shows that LAD WiFi Matching Positioning can not only have better robust ability to deal with the reference and check points AP signal strength error than LS WiFi Matching Positioning but also can detect the outlier in the reference points AP signal strength. In the real data, LAD WiFi Matching Positioning can also have better result. In the outdoor situation, the RMSE (Root Mean Square Error) of LAD WiFi Matching Positioning and LS (Least Squares) WiFi Matching Positioning are 8.46 meters and 8.57 meters respectively. In the indoor situation, the RMSE (Root Mean Square Error) of LAD WiFi Matching Positioning and LS (Least Squares) WiFi Matching Positioning are 2.20 meters and 2.41 meters respectively.

The thesis is focused on mapping of selected on-line services in hospitals in Czech Re-public according to their availability. In the next step logistic regression model will be used, which will measure a range of particular on-line services according to their legal form, majority ownership, region in which health organization is located, to education achieved and gender of hospital director and lastly in accordance with the size of hospital from the viewpoint of bed capacity. This thesis will provide comprehensive overview of availability of on-line services in Czech hospitals and determine which factors significantly decreasing or increasing chance of their occurrence on hospital websites.

Translated work is concerned with issue of reduction of production expenses and planning of production process in company for assembly operations of thermoblocks and aquablocks for gas kettles.In this work is wrote about planning of production and bid for a system of observing process of production cycle.

La préservation de l’environnement et des ressources naturelles pour les prochaines générations est aujourd’hui considérée comme un des axes les plus prioritaires dans presque tous les secteurs économiques. Le secteur des Technologies de l’Information et de la Communication est loin d’être épargné de cette tendance écologique. Nous considérons dans cette thèse la problématique de la conservation d’énergie dans le contexte technologique actuel caractérisé par: • La coexistence d’une multitude de technologies d’accès sans fil offrant un environnement riche et dynamique • Des terminaux mobiles multimodaux • Limitations persistantes des sources d’énergie sur les terminaux mobiles. Dans ce contexte très riche, les possibilités offertes aux usagers sont à double tranchant. D’un côté, elles peuvent très bien améliorer la QoS en offrant toujours la meilleure connectivité en fonction du contexte de l’utilisateur. D’un autre côté, et sans une bonne optimisation de la consommation d’énergie sur le terminal, la disponibilité de celui-ci peut vite diminuer et donc faire baisser la QoE à cause de l’énergie nécessaire pour gérer plusieurs interfaces radio en parallèle. Nous considérons essentiellement les liens entre les stations de base (ou les point d’accès) et les terminaux mobiles. Notre objectif étant d’analyser la consommation d’énergie sur ces liens pour ensuite proposer des contributions permettant de mieux la maitriser. Nous focalisons essentiellement sur l’exploitation des multiples interfaces et du multi-flux pour étudier, analyser et proposer des solutions dynamiques et adaptatives d’ordonnancement, de sélection et de gestion d’interfaces minimisant la consommation d’énergie / Since the last decades, environmental issues are becoming among the major concerns for most human activities, including the Information and Communication Technologies sector. This will surely influence upcoming networking technologies, architectures and usage practices. New approaches and methodologies are required in order to evaluate and to reduce the Carbon Footprint toward what is commonly denoted as Green Networks. Within the ICT sector, the main efforts are related to energy saving techniques. These efforts started in early stages within wireless technologies, mainly because of energy limitations on mobile devices such as mobile phones and wireless sensors. Additionally, because of health considerations, standardization bodies and government had set stringent policies and limits on electromagnetic radiation levels that can be emitted by radio stations. For these reasons, many academic and industrial research and development activities had led to a number of relatively energy efficient solutions. In this thesis, we consider energy efficiency in the context of Heterogeneous Wireless Access Networks. These are composed of multi-standards wireless network solutions, with non uniform topologies and cell sizes and Multi-Modal mobile terminals able to manage simultaneously different connections. The main contributions of our studies include the proposal of new optimization solutions regarding user association and scheduling techniques at both flow and packet levels for multi-homed mobile terminals. An overall context-based solution is also proposed in order to provide end-to-end energy efficient networking solutions

This master thesis deals with analysis of an implementation of a reputation system. I particularly focus on analysis of user interface and to find an approach for possible user interface improvements of such a reputation system. I describe possible solutions and I also compare my solution with similar existing systems that are also focused on network security. A part of the diploma thesis is devoted to user interface design. There is also mentioned a database design together with a way the users log on into the system. A few chapters are devoted to the area of data presentation and the usage of template system. In the work there are also described interesting issues that appeared during the implementation. In the conclusion of this work, there is an overall project evaluation and also several remarks about the possible upgrade.

Logging plays a crucial role in debugging endeavors, assisting technicians in identifying errors and improving the overall sustainability of electrical systems. This thesis focuses on integrating local logging capabilities into the Balise Transmission Module (BTM), a legacy control system that lacks such features. The project also aims to incorporate real-time remote logging functionalities. It should be noted that the BTM does not have power output, necessitating the logging system to derive energy from existing signals while ensuring the safe operation of the control system. The thesis starts by introducing the project’s context, then explains the system architecture and relevant background information. Subsequently, it delves into the design aspects of a power supply that efficiently extracts energy from the control system. Additionally, the thesis explores wireless data transfer solutions and local data storage alternatives, addressing other pertinent details related to the logging system. Finally, it presents an evaluation of the design and an analysis of the results. The power supply design was developed to incorporate in-rush current limiting, a buck converter, and current limiting mechanisms to ensure the safe operation of the BTM. Through simulations, this thesis demonstrates that the power supply can operate within the safe boundaries of the BTM while efficiently harnessing sufficient current to power the system. The wireless transmission protocols investigated in this study were Bluetooth Low Energy (BLE) and WiFi. The thesis evaluates BLE as sufficiently power-efficient but identifies throughput limitations due to the raw data generated by the BTM exceeding the available throughput. On the other hand, WiFi exhibits no throughput issues but consumes excessive power, making it unsuitable for legacy versions of the BTM. Flash memory was designed and implemented as a feasible solution for local storage. / Loggning spelar en avgörande roll i felsökning, vilket underlättar felidentifiering och förbättrar den övergripande hållbarheten för elektiska system. Detta arbete belyser processen att integrera lokala loggningsfunktioner i ett specifikt äldre kontrollsystem, Balise Transmission Module, som helt saknar sådana funktioner. Dessutom strävar projektet efter att integrera realtidsfunktioner för fjärrloggning. I detta särskilda fall saknar det äldre kontrollsystemet utgångseffekt, vilket kräver att loggningssystemet utnyttjar energi från befintliga signaler, utan att påverka kontrollsystemets drift. Arbetet inleds med att introducera projektets sammanhang, följt av en exposition av systemarkitekturen och relevant bakgrundsinformation som är associerad med denna arkitektur. Därefter går arbetet in på designaspekterna av strömförsöjningen som effektivt utvinner energi från kontrollsystemets befintliga signaler. Dessutom utforskas den trådlösa dataöverföringen och alternativ för lokal datalagring, och tar upp andra relevanta detaljer för loggingsystemet. Slutligen presenterar arbetet en utvärdering av designen och en analys av resultaten. Strömförsörjningsdesignen utvecklades för att inkludera begränsning av startström, en buck-omvandlare och strömbegränsningsmekanismer för att säkerställa säker drift av BTM. Genom simuleringar visar detta arbete att strömförsörjningen kan fungera inom de säkra gränserna för BTM samtidigt som den effektivt utvinner tillräcklig ström för att driva systemet. De trådlösa överföringsprotokoll som undersöktes i denna studie var Bluetooth Low Energy (BLE) och WiFi. Arbetet utvärderar BLE som tillräckligt energieffektivt, men identifierar genomströmningsbegränsningar på grund av att den råa data som genereras av BTM överstiger den tillgängliga genomströmningskapaciteten. Å andra sidan uppvisar WiFi inga genomströmningsproblem men förbrukar överdriven ström, vilket gör det olämpligt för äldre versioner av BTM. Flash-minne designades och implementerades som en genomförbar lösning för lokal lagring.

Wireless spectrum is a limited resource that must be used efficiently. It is also a broadcast medium, hence, additional procedures are required to maintain communication over the wireless spectrum private. In this thesis, we investigate three key issues related to efficient use and privacy of wireless spectrum use. First, we propose GAVEL, a truthful short-term auction mechanism that enables efficient use of the wireless spectrum through the licensed shared access model. Second, we propose CPRecycle, an improved Orthogonal Frequency Division Multiplexing (OFDM) receiver that retrieves useful information from the cyclic prefix for interference mitigation thus improving spectral efficiency. Third and finally, we propose WiFi Glass, an attack vector on home WiFi networks to infer private information about home occupants. First we consider, spectrum auctions. Existing short-term spectrum auctions do not satisfy all the features required for a heterogeneous spectrum market. We discover that this is due to the underlying auction format, the sealed bid auction. We propose GAVEL, a truthful auction mechanism, that is based on the ascending bid auction format, that avoids the pitfalls of existing auction mechanisms that are based on the sealed bid auction format. Using extensive simulations we observe that GAVEL can achieve better performance than existing mechanisms. Second, we study the use of cyclic prefix in Orthogonal Frequency Division Multiplexing. The cyclic prefix does contain useful information in the presence of interference. We discover that while the signal of interest is redundant in the cyclic prefix, the interference component varies significantly. We use this insight to design CPRecycle, an improved OFDM receiver that is capable of using the information in the cyclic prefix to mitigate various types of interference. It improves spectral efficiency by decoding packets in the presence of interference. CPRecycle require changes to the OFDM receiver and can be deployed in most networks today. Finally, home WiFi networks are considered private when encryption is enabled using WPA2. However, experiments conducted in real homes, show that the wireless activity on the home network can be used to infer occupancy and activity states such as sleeping and watching television. With this insight, we propose WiFi Glass, an attack vector that can be used to infer occupancy and activity states (limited to three activity classes), using only the passively sniffed WiFi signal from the home environment. Evaluation with real data shows that in most of the cases, only about 15 minutes of sniffed WiFi signal is required to infer private information, highlighting the need for countermeasures.

The surge of mobile devices, such as smartphones, and tables, demands additional capacity. On the other hand, Internet-of-Things (IoT) and smart grid, which connects numerous sensors, devices, and machines require ubiquitous connectivity and data security. Additionally, some use cases, such as automated manufacturing process, automated transportation, and smart grid, require latency as low as 1 ms, and reliability as high as 99.99\%. To enhance throughput and support massive connectivity, sharing of the unlicensed spectrum (3.5 GHz, 5GHz, and mmWave) is a potential solution. On the other hand, to address the latency, drastic changes in the network architecture is required. The fifth generation (5G) cellular networks will embrace the spectrum sharing and network architecture modifications to address the throughput enhancement, massive connectivity, and low latency. To utilize the unlicensed spectrum, we propose a fixed duty cycle based coexistence of LTE and WiFi, in which the duty cycle of LTE transmission can be adjusted based on the amount of data. In the second approach, a multi-arm bandit learning based coexistence of LTE and WiFi has been developed. The duty cycle of transmission and downlink power are adapted through the exploration and exploitation. This approach improves the aggregated capacity by 33\%, along with cell edge and energy efficiency enhancement. We also investigate the performance of LTE and ZigBee coexistence using smart grid as a scenario. In case of low latency, we summarize the existing works into three domains in the context of 5G networks: core, radio and caching networks. Along with this, fundamental constraints for achieving low latency are identified followed by a general overview of exemplary 5G networks. Besides that, a loop-free, low latency and local-decision based routing protocol is derived in the context of smart grid. This approach ensures low latency and reliable data communication for stationary devices. To address data security in wireless communication, we introduce a geo-location based data encryption, along with node authentication by k-nearest neighbor algorithm. In the second approach, node authentication by the support vector machine, along with public-private key management, is proposed. Both approaches ensure data security without increasing the packet overhead compared to the existing approaches.

Dans cette thèse, nous étudions plusieurs méthodes pour la mise en place de la QoS<br />(Quality of Service) dans un réseau IP. Avant d'entamer nos travaux de recherche, nous<br />dévoilons tout d'abord les différents mécanismes de QoS que nous étudierons dans la thèse.<br />MPLS (Multi Protocol Label Switching), DiffServ (Differentiated Services) et les algorithmes<br />d'ordonnancement formeront la base du réseau coeur que nous utiliserons. En accord avec<br />plusieurs travaux, nous définissons trois classes de service à différencier dans le réseau. La<br />première classe comporte les flux voix. Elle nécessite un délai faible et une gigue réduite. Les<br />flux de "données critiques", qui requièrent un taux de perte faible et un délai borné, forme la<br />deuxième classe. La troisième classe, qui regroupe les applications telles que le transfert de<br />fichiers ou l'échange de courriers électroniques, n'exige aucune condition particulière du<br />réseau.<br />Dans un premier temps, nous modélisons les flux sortant/entrant d'un réseau mobile<br />sans fil. D'abord, nous modélisons les lois d'inter arrivée des paquets d'un flux agrégé au<br />niveau de la couche MAC (Medium Access Control) entrant au réseau UTRAN (UMTS<br />Terrestrial Radio Access Network), le réseau d'accès à l'UMTS (Universal Mobile<br />Telecommunication Service). Le protocole CDMA (Code Division Multiple Access) utilisé<br />dans ce réseau propose un accès différent en fonction de la QoS demandée. Ensuite, nous<br />déterminons la loi caractérisant l'inter arrivée des paquets sortant d'un réseau WiFi (Wireless<br />Fidelity) utilisant la couche MAC 802.11 de base. Pour ces deux réseaux, nous proposons<br />différents modèles d'agrégation de flux voix, Web, transfert de fichiers ou un multiplexage de<br />ces différentes classes. Nous mesurons l'adéquation de deux modèles de loi de distributions<br />aux traces créées. La première distribution est le processus MMPP (Markov Modulated<br />Poisson Process) qui représente un modèle Markovien. Nous expérimentons deux valeurs du<br />nombre d'états: 2 et 4. La seconde loi que nous considérons est la loi Gaussienne. Nos<br />résultats montrent que d'une part, le type des flux agrégés et d'autre part, le réseau utilisé,<br />influent tous les deux sur le modèle produit.<br />Dans un second temps, nous développons les équations qui déterminent les<br />probabilités stationnaires d'une file d'attente implémentant l'ordonnanceur GPS (Generalised<br />Processor Sharing) avec trois classes de service. En utilisant le mécanisme DiffServ pour<br />différencier les flux, nous mesurons la QoS à la sortie d'une file unique utilisant WRR<br />(Weighted Round Robin), un des algorithmes qui approximent GPS. Nous traçons alors les<br />différentes courbes de délai et de taux de perte observés à la sortie de cette file en fonction de<br />la pondération et de la charge créée par chacune des classes. Nous appliquons les différentes<br />conclusions du choix des paramètres que nous tirons d'un seul serveur à un réseau entier. De<br />plus, nous ajoutons l'ingénierie de trafic de MPLS pour quantifier le gain mesuré par chaque<br />politique. A partir de ce travail, nous avons pu généraliser nos constatations qui deviennent<br />valable aussi bien sur une file que dans un réseau.<br />Dans un troisième temps, nous développons une méthode d'adaptation dynamique du<br />routage. Nous la proposons afin de palier aux variations de la distribution du délai sur les<br />liens qui forment le chemin de bout en bout. Ce mécanisme se base sur les techniques de<br />tomographie des réseaux afin d'estimer la distribution du délai sur les différents tronçons des<br />chemins observés. Si le délai moyen sur la route utilisée reste supérieur d'un seuil ε pendant<br />un temps τ au délai moyen d'un autre chemin, le mécanisme déclenche alors la procédure de<br />modification du chemin emprunté. C'est l'utilisation du protocole MPLS associé à ce<br />mécanisme qui permet une modification souple et rapide des itinéraires.