Abstract The present dissertation deals with initial synchronization in Code Division Multiple Access (CDMA) networks. In the first part of this thesis an extensive and up-to-date review of the literature is presented. The basic theory of code acquisition as well as different techniques and structures used to achieve the initial synchronization are discussed. A survey of the most common theoretical approaches allowing performance characterization of the acquisition process is included. The effect of noise, interference, carrier Doppler, multipath propagation, fading and data modulation on system performance are reviewed. Advanced code acquisition approaches exploiting interference suppression techniques and multiple antennas are also described. A summary of the results obtained within the area of code acquisition in CDMA networks is also embraced by this thesis. The distinctive assumption is to consider the actual variable effect of multiple access interference on the delay-domain search process, instead of the usual constant approximation. Three directions of research are followed. Models for code acquisition in quasi-synchronous and asynchronous CDMA networks are first developed and analysed. Closed-form expressions for the main performance figures of the acquisition process are derived and analysed. Results show a strong dependence of the mean acquisition time with the nature of the multiple access interference. In the second area of research the previous results are extended to consider code acquisition with a multi-branch (Rake) receiver in a multipath channel. A generic model for Rake receiver code acquisition is considered and developed, in which the synchronization takes place in two phases. The first detected path is allocated to the first finger during the initial synchronization phase, whereas the remaining fingers are successively allocated to other available paths in the postinitial synchronization phase. Performance measures for this acquisition process are also derived and analysed. Finally, based on the use of an antenna array and beamforming techniques, conventional delay-domain code acquisition is extended to the angular domain, resulting in a two-dimensional (delay-angle) search. This technique is found to be feasible, outperforming the synchronization approach exploiting a single-antenna. It is found that there exists an optimal number of antennas that minimises the mean acquisition time. Two-dimensional code acquisition is studied in a variety of scenarios, including single and multipath channels, fixed and fading channels, and with uniform and nonuniform spatial distributions of interference. Different two-dimensional search strategies are studied. A clear dependence of acquisition performance with the search strategy and the particular distribution of interference is pointed out. The performance of two-dimensional code acquisition is found to be seriously deteriorated by the presence of spatially nonuniform interference. Schemes based on search strategy and adaptive detector structures are considered and analysed to combat the performance degradation in the mentioned case. A comparative study of code acquisition exploiting multiple antennas is also presented.

Abstract The current Internet infrastructure must be architected to handle future media-rich, and content rich applications. The success of applications such as video-on-demand, multicast and content distribution depends on Quality of Service and bandwidth guarantees. Over the years, the Internet has encompassed many changes in traffic profiles and applications, in bandwidths and utilization, but the future Internet infrastructure necessitates a very different architecture supporting Quality of Service (QoS). A satellite, distinguished by features such as global coverage, bandwidth flexibility, broadcast, multicast, and reliability, is an excellent candidate to provide broadband integrated Internet access. The aim of this thesis is to explore suitability of satellite technologies for broadband Internet services with significant emphasis on the question of defining, assessing, and developing QoS models for satellite ATM and IP broadband networks with and without onboard processing. For the satellite Internet, Transmission Control Protocol (TCP) performance is degraded due to long propagation delays, link errors, and bandwidth asymmetry. In this thesis, for satellite ATM, fundamental questions such as buffer requirements, TCP/ATM efficiency, fairness, and multiple access are addressed through extensive simulations in a quantitative way. Buffer designs for TCP over satellite ATM Unspecified Bit Rate (UBR) service are performed. A buffer size equal to half the round trip delay-bandwidth product of the TCP connections provides high efficiency for TCP over satellite UBR. An extensive TCP analysis via simulation study for various TCP mechanisms and end system policies show that for satellite environment end system policies are more important than switch drop policies in terms of efficiency and fairness for World Wide Web traffic. A bandwidth allocation scheme is proposed and analytical model for supporting voice and video service over a broadband satellite network is developed. The study results demonstrate that non-contiguous allocation can afford higher gain in uplink utilizations. In this thesis, for the first time, Integrated Services and Differentiated Services based QoS architectures for broadband satellite IP networks are proposed and analyzed. In multimedia applications where User Datagram Protocol (UDP) is used along with TCP, a fair excess bandwidth allocation is not possible because TCP is congestion sensitive whereas UDP is congestion insensitive. An extensive simulation model is developed to study the effect of precedence levels for reserved rate utilization and fairness with different buffer management policies. The simulation results indicate that three levels of precedence are required for better utilization. Multiprotocol Label Switching (MPLS) over Satellite network has been proposed and a simulation model developed to study the throughput performance impacts for TCP and UDP. The traffic engineering of MPLS facilitates efficient and reliable network design to optimize the utilization of network resources and enhance the network QoS. A novel Code Division Multiple Access based Spread ALOHA single code multiple access scheme for broadband satellite return channel is proposed as an alternative to Multifrequency-Time Division Multiple Access based Digital Video Broadcasting-Return Channel via Satellite protocol. It is shown through Monte Carlo simulations that throughput for Spread ALOHA One Long Code equivalent to packet length, is better than Spread ALOHA One Code in which spreading sequence repeats every symbol. The reduction of throughput due to multi-user interference for different number of users is shown. Further research on QoS architectures, performance models for TCP enhancements, interworking functions, interoperability, and standardization efforts is included.

La résistance aux antibiotiques demeure un problème majeur de santé publique particulièrement dans les pays en voie de développement (PVD) où les conditions d’hygiène sont encore précaires et où l’utilisation des antibiotiques est souvent abusive et très peu contrôlée. Cette thèse a pour objectif principal d’étudier la prévalence, la circulation et la caractérisation génétique des bactéries multirésistantes (BMR) dans un PVD, le Burkina Faso. Ce travail permet de mieux comprendre la propagation de ces BMR dans ce pays et de donner des informations indispensables pour les services de santé publique. Dans cette région, c’est la première étude du genre et cette thèse représente donc un travail original et informatif. A partir d’une revue de la littérature réalisée sur la problématique de l’émergence des BMR en Afrique de l’ouest, les objectifs spécifiques sont : i) d’étudier la prévalence et la caractérisation phénotypique et génotypique des bêta-lactamases à spectre élargi (BLSE) chez les entérobactéries isolées en portage et dans les processus infectieux ; ii) d’évaluer la sensibilité des entérobactéries aux carbapénèmes ; iii) de documenter la prévalence du portage nasal de Staphylococcus aureus (SAUR) résistant à la méticilline (SARM) ainsi que d’effectuer la caractérisation moléculaire les isolats de SAUR. Les isolats ont été prélevés par les services de santé publique au sein des 3 CHU du Burkina et ont été remis en culture au laboratoire de bactériologie du CHU de Montpellier [un total de 594 souches, 522 entérobactéries (214 en portage et 308 dans les processus infectieux) et 72 SAUR]. L’identification des espèces bactériennes repose sur la spectrométrie de masse MALDI-TOF. L’évaluation de la sensibilité aux antibiotiques s’appuie sur la méthode de diffusion en milieu gélosé. Les BLSE et les carbapénémases chez les entérobactéries sont identifiées par méthodes moléculaires (PCR et séquençage) et la caractérisation génétique des isolats de SAUR par une technique de puce à ADN. Au Burkina Faso, les points importants sont : des taux très élevés en portage et dans les infections d’entérobactéries sécrétrices de BLSE en hospitalier et en communautaire; les antécédents de consommation d’antibiotiques ou d’hospitalisation sont des facteurs de risque de portage ; par les isolats BLSE, Escherichia coli est l’espèce prédominante ; la majorité des BLSE sont des CTX-M-15, suivi de CTX-M-14, 27 et SHV-12 ; l’étude des phylogroupes d’E. coli suggère une expansion des gènes CTX-M-15 d’origine plasmidique et non liée à une épidémie de clone ; des isolats d’E. coli producteurs de carbapénémase OXA-181 avec un support génétique plasmidique de type IncX3 sont identifiés. On observe un taux de portage nasal de SAUR classique avec une très faible prévalence de SARM ; on note dans une forte proportion des gènes de virulence (Leucocidine de Panton Valentin et du facteur EDIN) parmi les SAUR en portage constituant des facteurs de risques de gravité lors des infections ; l’analyse génétique des isolats de SAUR montre une grande diversité de clones. Les études de prévalence et de génétiques apportent des informations fondamentales pour l’épidémiologie des BMR, base indispensable pour appréhender la lutte et le contrôle de ces organismes pathogènes résistants. En conclusion, ces premières études réalisées au Burkina permettent de définir les perspectives de recherche et les stratégies à développer pour le contrôle l’émergence et la diffusion de ces BMR. / Antibiotic resistance is a major public health issue, particularly in developing countries where health conditions are still inadequate and antibiotic use is often unjustified and not properly regulated. The main objective of this thesis was to study the prevalence, spread and genetic features of multi-resistant bacteria (MRB) in Burkina Faso, a developing country. This work allows better understanding MRB spread in this country and gives essential information for the development of public health policies. This is the first study in this region and this thesis is therefore an original and informative work. Starting from a review of the literature data on the issue of MRB emergence in West Africa, the specific objectives are: i) to study the prevalence and to characterize phenotypically and genotypically the extended-spectrum beta lactamases (ESBL) in enterobacterial samples isolated from healthy carriers and during the clinical phase of infection; ii) to assess the sensitivity of such enterobacterial samples to carbapenem drugs; iii) to document the prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) and to molecularly characterize all S. aureus isolates. Samples were collected by the public health services of three Burkina Faso University Hospital Centers (UHC) and were then cultured at the Laboratory of Bacteriology of Montpellier UHC [total n= 594 isolates of which 522 were Enterobacteriaceae isolates (214 from healthy carriers and 308 from patients with clinical infection) and 72 S. aureus isolates]. Bacterial species were identified by MALDI-TOF mass spectrometry. Antibiotic sensitivity was tested using the agar diffusion method. ESBL and carbapenemases in enterobacterial isolates were identified using molecular methods (PCR amplification and sequencing). S. aureus isolates were genetically characterized by using DNA arrays. This work shows that in Burkina Faso, ESBL-producing enterobacterial strains are frequent both in healthy carriers and hospitalized patients and that previous antibiotic use or hospitalizations are risk factors for colonization. Among the ESBL-producing enterobacterial strains, Escherichia coli was the predominant species and most ESBL-producing isolates were CTX-M-15, followed by CTX-M-14, 27 and SHV-12. The analysis of the E. coli phylogenetic groups suggests a plasmid-mediated spread of CTX-M-15 genes and not linked to an epidemic clone. Moreover, E. coli strains that produce the carbapenemase OXA-181 and with an IncX3-type plasmid have been identified. Concerning S. aureus, the rate of nasal carriage was classical with a low prevalence of MRSA. Among the S. aureus nasal samples, a high proportion of virulence genes (Panton Valentin leukocidin and EDIN) was detected. This constitutes an important risk of severe disease during clinical infection. The genetic analysis of the S. aureus isolates showed great clone diversity. These data are essential for understanding MRB epidemiology in Burkina Faso and represent a base for fighting and controlling resistant pathogens. In conclusion, these first studies carried out in Burkina Faso allow defining the future research perspectives and strategies to be developed for controlling the emergence and spread of these MRB.

In spread spectrum systems employing parity bit selected spreading sequences, parity bits generated from a linear block encoder are used to select a spreading code from a set of mutually orthogonal spreading sequences. In this thesis, turbo receivers for SS-PB systems are proposed and investigated. In the transmitter, data bits are rst convolutionally encoded before being fed into SS-PB modulator. In fact, the parity bit spreading code selection technique acts as an inner encoder in this system without allocating any transmit energy to the additional redundancy provided by this technique. The receiver implements a turbo processing by iteratively exchanging the soft information on coded bits between a SISO detector and a SISO decoder. In this system, detection is performed by incorporating the extrinsic information provided by the decoder in the last iteration into the received signal to calculate the likelihood of each detected bit in terms of LLR which is used as the input for a SISO decoder. In addition, SISO detectors are proposed for MC-CDMA and MIMO-CDMA systems that employ parity bit selected and permutation spreading. In the case of multiuser scenario, a turbo SISO multiuser detector is introduced for SS-PB systems for both synchronous and asynchronous channels. In such systems, MAI is estimated from the extrinsic information provided by the SISO channel decoder in the previous iteration. SISO multiuser detectors are also proposed for the case of multiple users in MC-CDMA and MIMO-CDMA systems when parity bit selected and permutation spreading are used. Simulations performed for all the proposed turbo receivers show a signi cant reduction in BER in AWGN and fading channels over multiple iterations.

In the study the first part is focused on anylysing the U.S. corporate bond market especially its imporance and progress. Second part is devoted structured products which are integrated in the corporate bond market in USA. Last part is focused on historical yields and especially credit spreads of corporate bonds and the factors which influence them.

Le chemin parcouru par la lumière, lors de sa propagation dans l’Univers, est altéré par la présence d’objets massifs. Cela entraine une déformation des images de galaxies lointaines. La mesure de cet effet, dit de lentille gravitationnelle faible, nous permet de sonder la structure, aux grandes échelles, de notre Univers. En particulier, nous pouvons ainsi étudier la distribution de la matière noire et les propriétés de l’Energie Sombre, proposée comme origine de l’accélération de l’expansion de l’Univers. L’étude de l'effet de lentille gravitationnelle faible constitue l’un des objectifs scientifiques principaux d'Euclid, un télescope spatial de l’Agence Spatiale Européenne en cours de construction.En pratique, ce signal est obtenu en mesurant la forme des galaxies. Toute image produite par un instrument optique est altérée par sa fonction d’étalement du point (PSF). Celle-ci a diverses origines : diffraction, imperfections dans les composantes optiques de l’instrument, effets atmosphériques (pour les télescopes au sol)… Puisque la PSF affecte aussi les formes des galaxies, il est crucial de la prendre en compte lorsque l’on étudie l’effet de lentille gravitationnelle faible, ce qui nécessite de très bien connaître la PSF elle-même.Celle-ci varie en fonction de la position dans le plan focal. Une mesure de la PSF, à certaines positions, est donnée par l’observation d’étoiles non-résolues dans le champ, à partir desquelles on peut construire un modèle de PSF. Dans le cas d’Euclid, ces images d’étoiles seront sous-échantillonnée ; aussi le modèle de PSF devra-t-il contenir une étape de super-résolution. En raison de la très large bande d’intégration de l’imageur visible d’Euclid, il sera également nécessaire de capturer les variations en longueur d’onde de la PSF.La contribution principale de cette thèse consiste en le développement de méthodes novatrices d’estimation de la PSF, reposant sur plusieurs outils : la notion de représentation parcimonieuse, et le transport optimal numérique. Ce dernier nous permet de proposer la première méthode capable de fournir un modèle polychromatique de la PSF, construit uniquement à partir d’images sous-échantillonnées d’étoiles et leur spectre. Une étude de la propagation des erreurs de PSF sur la mesure de forme de galaxies est également proposée. / As light propagates through the Universe, its path is altered by the presence of massive objects. This causes a distortion of the images of distant galaxies. Measuring this effect, called weak gravitational lensing, allows us to probe the large scale structure of the Universe. This makes it a powerful source of cosmological insight, and can in particular be used to study the distribution of dark matter and the nature of Dark Energy. The European Space Agency’s upcoming Euclid mission is a spaceborne telescope with weak lensing as one of its primary science objectives.In practice, the weak lensing signal is recovered from the measurement of the shapes of galaxies. The images obtained by any optical instrument are altered by its Point Spread Function (PSF), caused by various effects: diffraction, imperfect optics, atmospheric turbulence (for ground-based telescopes)… Since the PSF also alters galaxy shapes, it is crucial to correct for it when performing weak lensing measurements. This, in turn, requires precise knowledge of the PSF itself.The PSF varies depending on the position of objects within the instrument’s focal plane. Unresolved stars in the field provide a measurement of the PSF at given positions, from which a PSF model can be built. In the case of Euclid, star images will suffer from undersampling. The PSF model will thus need to perform a super-resolution step. In addition, because of the very wide band of its visible instrument, variations of the PSF with the wavelength of incoming light will also need to be accounted for.The main contribution of this thesis is the building of novel PSF modelling approaches. These rely on sparsity and numerical optimal transport. The latter enables us to propose the first method capable of building a polychromatic PSF model, using no information other than undersampled star images, their position and spectra. We also study the propagation of errors in the PSF to the measurement of galaxy shapes.

Interior flat, white latex paint is a common coating applied to walls around the world. Development of a coating with one coat hide capability is a pinnacle achievement for paint formulators as it has the potential to save consumers both time and money. One coat paints already exist on the market, but they are limited in color, coverage, and often have many disclaimers. Work done was part of a project initiated by ChemoursTM Titanium Technologies. The goal of the project presented in this article was to create an interior flat, white latex paint that yields a spread rate of greater than 400 ft2/gal., which is advertised by many below critical pigment volume concentration (CPVC) commercial paints. In order to achieve this goal, an above CPVC paint with a high TiO2 content was created and continuously improved. Improvement of the formulation involved numerous experimental variations including adjustments to the hydroxyethylcellulose (HEC) molecular weight, dispersant chemistry, latex chemistry, TiO2 concentration, extender package, and rheology modifier type. The sheen value, relative light scattering, and spread rate were the main measurements conducted in order to judge formulation improvement. Complications with the spread rate procedure forced its adaptation in order to collect less variable data with the high density, shear thinning formulations. It was found that shorter opacity charts yielded more precise spread rate data than the longer opacity charts. An attempt at correlating rheology with sheen development resulted in the conclusion that the pigment and extender particle package is the greatest driving factor behind sheen reduction. The rheology modifier type and dispersant chemistry did not affect the flatness of the paint nearly as much. A Keyence VR-3000 series One-Shot 3D Measuring Macroscope was used to show that surface roughness does not directly correlate to the sheen value when a number of flat paints with different sheens were analyzed. This project is an ongoing effort and the information contained in this document will substantially help future development.

This diploma thesis deals with the displaying process evaluation from the resolution capabilities of the ultra-sonic probe point of view. As a part of the thesis a method for measuring the response from point spread function (PSF) and method for measuring the response from linear spread function LSF were designed. Collected data were processed in the Matlab environment. Basic evaluation parameters of the space resolution capabilities were set and used – axial, lateral and traversal resolution.

Ingeniero Civil Eléctrico / Grandes empresas relacionadas a la innovación en telecomunicaciones a nivel mundial como IBM, CISCO y Nokia están desarrollando nuevas tecnologías y servicios para el Internet of Things (IoT), entre ellas nuevas técnicas de modulación de señales, como Chirp Spread Spectrum (CSS), que han permitido la creación de un nuevo tipo de redes de bajo consumo y grandes áreas de cobertura. El termino acuñado para estas redes es Low Power Wide Area Networks (LPWAN) y ellas se caracterizan por lograr rangos de cobertura del orden de los kilómetros, pero con un consumo de energía mínimo que permite mantener los nodos de la red por años en funcionamiento de manera remota sin un cambio de batería. El desarrollo de este nuevo tipo de redes va de la mano con la aparición de las Wireless Sensor Network (WSN), redes ubicuas y redes mesh acercándonos a un futuro en donde se pueda conocer y controlar diversos aspectos de nuestro entorno de forma remota, en tiempo real y a bajo costo. La tecnología estudiada en este trabajo es LoRa la cual permite enviar información con un bajo costo energético y ser recibida a largas distancias gracias a sus altos niveles de sensibilidad (-130[dBm]). En este trabajo se explicarán en detalle los fundamentos de estas características y se mostrará el análisis gráfico de un radio-enlace de LoRa en un ambiente urbano. El estudio fue llevado a cabo en la ciudad de Santiago Chile, en la intersección de las comunas de Macul y Ñuñoa. Se integraron distintos Hardwares para crear un sistema de comunicación inalámbrico LoRa que opera en la banda ISM de 915[MHz] y permite asociar los parámetros del radio enlace con su respectiva posición georreferenciada. Fue posible obtener rangos de buena cobertura entre los 500[m] y los 700[m], y ademas se encontraron zonas de cobertura adicional a aproximadamente 1[km] de distancia entre el nodo transmisor y la estación base. Esta memoria es parcialmente financiada por Telefónica Investigación y Desarrollo Chile, con el objetivo de desarrollar pruebas reales que permitan analizar y validar los resultados teóricos ofrecidos por esta nueva tecnología y además hacerse del Know How necesario para utilizar estas tecnologías en desarrollos nacionales. / Este trabajo ha sido parcialmente financiado por Telefónica Investigación y Desarrollo Chile

Brandskyddet hos nya och gamla konstruktioner har blivit en väsentlig del av byggnadens säkerhet de senaste 70 åren. En av byggnadstyperna med högst skydd i form av brandskydd är sjukhus. I Sverige har sjukhus en generellt hög säkerhet, detta eftersom vissa personer har svårt att röra sig eller till och med är nedsövda. Även om dimensioneringen av dagens sjukhus utgår från ett högt brandskydd och säkerhetstänk, kan det finnas brister i det befintliga brandskyddet.   Examensarbetet syftar till att undersöka om luftslussens funktion avseende brandskydd mellan vårdavdelningar på sjukus och om de uppfyller den funktion som beskrivs i dagens regelverk. Detta kontrollerades genom att genomföra en litteraturstudie om varför och hur luftslussen har den funktion som den har idag. Det visar sig att under de senaste 25 åren har luftslussen i regelverken inte utvecklats. När bakgrundsinformationen var hämtad, genomfördes ett studiebesök på ett sjukhus där utrymningsövning med säng gjordes. Anledningen till detta var att beräkna medelhastighet för utrymning med säng och tid respektive dörr är öppen i luftslussen samt hur lång tid det tar att utrymma för att sedan återinträda till vårdnadssalen. Baserat på dessa tider gjordes sedan sex stycken databeräkningar med olika brandeffekter. Effekterna gjordes med och utan sprinkler samt med och utan luftsluss.   De sex CFD-beräkningarna delades in i tre fall. Det första fallet var en sängbrand med 800 kW som brandeffekt. Andra och tredje fallet illustrerade en 5 MW brand som effekt där ena fallet var med sprinkler och det andra utan. Varje fall bestod av två databeräkningar, ena beräkningen var med en luftsluss där dörrarna hade samma funktion som de hade på sjukhuset. Den andra var enbart med en dörr istället för luftsluss.   Utdatafilerna analyserades och jämfördes med varandra, först mot fallet med eller utan luftsluss och sedan mot de olika brandeffekterna. Detta gjordes för att se om någon brandgasspridning skedde beroende på om det var luftsluss eller ej och vid vilken brandeffekt samt tid brandgasspridning sker.   Resultaten visar att i alla databeräkningarna sker det brandgasspridning till intilliggande brandcell oavsett om det är luftsluss eller ej. Den enda modellen som luftslussen medför ett visst skydd mot brandgasspridning är vid sängbranden, men det är endast vid första passagen vilket ej kan anses uppfylla kravet.   Eftersom detta är en brist i de befintliga brandskyddsreglerna om hur ett sjukhus ska dimensioneras gällande luftslussarnas utformning, bör revideringar ske då brandgasspridning äger rum oavsett om det är luftsluss eller ej. För att personer ska känna sig säkra gällande skydd mot bränder bör ett bra brandskydd vara upprättat. Ett alternativ som används idag istället för luftsluss är att endast ha en brandklassad dörr, och sedan trycksätta intilliggande brandcell så ej brandgasen sprider sig. / For the past 70 years the safety protection of new and old construction has become very substantially, especially regarding fire protection. In form of fire protection, one of the most protective buildings is hospitals. In Sweden, hospitals has a generally high safe protection. People that are visiting the hospital could be visitors, victims or even anesthetized so the fire safety is important.   The purpose of this report is to investigate if the airlock functions at Swedish hospitals between different care sections fulfill the regulations. A literature study was made to understand why the regulations regarding airlocks at hospitals are formed the way they are. It resulted in that the regulations regarding airlocks haven’t been changed for the past 25 years. The report continued with a visit to a local hospital. An evacuation with hospital beds was made to gather information to the CFD calculations to know how the airlock doors was operating. The process was to start the evacuation based on a timer and stop the clock when the staff returned through the first door of the airlock and waited for the door to close.   A room was programmed in Pyrosim based on a real hospital section with an airlock that connected two rooms. The programming was based on the evacuation. Totally there were six CFD calculations with three different cases. Two different effects was used to illustrate the fire. A 800 kW hospital bed fire and two with the effect of 5 MW, one with sprinkler and the other without. The purpose of the data analysis was to investigate smoke movements and penetration within hospital facilities.   The data calculations showed that all 6 of the cases failed and smoke was penetrated through the airlock. Only one of the cases was able to withstand to 300 seconds and the other one failed at the first passage.   The results shows that there are a deficiency in the current regulation accordning the fire safety. An alternative that is used today when projecting a hospital, is to replace the airlock with a door and pressurize the room next door so that the smoke won’t spread as fast. Although pressurized rooms are used today, they need to be tested if they work. And if they do, be replacing the currently used airlocks.