Spelling suggestions: "subject:"rank"" "subject:"rain""
111 |
Reducing Power Consumption For Signal Computation in Radio Access Networks : Optimization With Linear Programming and Graph Attention Networks / Reducering av energiförbrukning för signalberäkning i radioaccessnätverk : Optimering med linjär programmering och graf uppmärksamhets nätverkNordberg, Martin January 2023 (has links)
There is an ever-increasing usage of mobile data with global traffic having reached 115 exabytes per month at the end of 2022 for mobile data traffic including fixed wireless access. This is projected to grow up to 453 exabytes at the end of 2028, according to Ericssons 2022 mobile data traffic outlook report. To meet the increasing demand radio access networks (RAN) used for mobile communication are continuously being improved with the current generation enabling larger virtualization of the network through the Cloud RAN (C-RAN) architecture. This facilitates the usage of commercial off-the-shelf servers (COTS) in the network replacing specialized hardware servers and making it easier to scale up or down the network capacity after traffic demand. This thesis looks at how we can efficiently identify servers needed to meet traffic demand in a network consisting of both COTS servers and specialized hardware servers while trying to reduce the energy consumption of the network. We model the problem as a network where the antennas and radio heads are connectedto the core network through a C-RAN and a specialized hardware layer. The network is then represented using a graph where the nodes represent servers in the network. Using this problem model as a base we then generate problem instances with varying topologies, server profiles, and traffic demands. To find out how the traffic should be passed through the network we test two different methods: A mixed integer linear programming (MILP) method focused on energy minimization and a graph attention network (GAT) predictor combined with the energy minimization MILP. To help evaluate the results we also create three other methods: a MILP model that tries to spread the traffic as evenly as possible, a random predictor combined with the energy minimization MILP and a greedy method. Our results show that the energy optimization MILP method can be used to create optimal solutions, but it suffer from a slow computation time compared to the other methods. The GAT model shows promising results in making predictions regarding what servers should be included in a network making it possible to reduce the problem size and solve it faster with MILP. The mean energy cost of the solutions created using the combined GAT/MILP method was 4% more than just using MILP but the time gain was substantial for problems of similar size as the GAT was trained on. With regards to computation time the combined GAT/MILP method used was 85% faster than using only MILP. For networks of almost double the size than the ones that the GAT model was trained on the solutions of the combined GAT and MILP methods had a mean energy cost increase of 7% while still showing a strong speedup, being 93% faster than when only using MILP.
|
112 |
The effect of RAN inhibition on human colorectal cancer cells (CRC)Elrewey, Hussein A.S. January 2020 (has links)
Colorectal cancer (CRC) is the third most widespread and fourth most fatal
malignancy disease. The CRC from a primary site can spread to other tissues,
forming secondary tumours. CRC can metastasise to the liver through the effect
of K-Ras and Pten mutation (Mt.) (Abbas et al. 2020). This study aimed to assess
the hypothesis that the Ran inhibitor mebendazole MBZ reduces cell invasion
and metastasis of CRC. I have investigated MBZ effect on the CRC isogenic
human cell lines with specific mutations (HCT-116 K-Ras, DLD-1 K-Ras and Pten
deletion and wild type HCT-116 and DKO-3. I used qRT-PCR and western
blotting to identify expression levels of various genes and signalling molecules
after treatment with 0.5 mM MBZ. In addition, several assays were performed to
investigate MBZ effect on biological properties of the cells such as proliferation,
migration, invasion, and colony formation. MBZ downregulated Ran and induced
apoptosis through inhibition of Bcl-2 expression as well as inducing caspase -3,
-7, -9 and PARP cleavage. Moreover, MBZ showed an effect on immune
response by down regulating C5a, IL-1ß and IL-1α analysed at mRNA level.
When treated with MBZ, the migration, invasion and colony formation abilities of
HCT-116 K-Ras Mt., DLD-1 K-Ras Mt. and HCT-116 Pten-/- were significantly
reduced compared to a control treated cell line. This was also the case with wild type cell lines such as HCT-116 and DKO-3. Furthermore, signalling molecules
such as p- Erk 1/2 and p- Akt were upregulated after MBZ treatment and exert
inhibition on Akt 1/2/3 and VEGFR1/2 mRNA levels. In conclusion; MBZ which is
a Ran inhibitor, has significantly reduced proliferation, colony formation, and
migration in colorectal cell lines with K-Ras and Pten gene deletion compared to
wild type cells in a dose-dependent manner. This work paves the way to clinical
validation of MBZ as a combination therapy for reducing the invasion of CRC
cells.
|
113 |
From Vulnerability to Resilience: Securing Signal Transmission Against Jamming and Spoofing AttacksYang, Hanchao 13 January 2025 (has links)
Wireless signal transmission underpins crucial aspects of modern communication, but its susceptibility to jamming and spoofing attacks remains a major concern. These attacks have the potential to disrupt vital services, mislead devices, and compromise the integrity of wireless systems.
Many researchers have addressed anti-jamming and anti-spoofing techniques. Anti-jamming methods include coding techniques, specialized waveforms (e.g., spreading, beamforming, and modulation), and spatial avoidance using relays or reflectors. Anti-spoofing methods include angle-of-arrival detection with antenna arrays, cross-checking with sensor fusion, and authentication and encryption. In recent decades, artificial intelligence and machine learning have boosted the research in anti-jamming and anti-spoofing, making them more flourish.
Despite these advancements, significant challenges persist. For example, while various jamming resistance studies were proposed, their application to vulnerable 5G and narrowband Internet of Things (NB-IoT) communications are unexplored. Additionally, while low-density sparse coding (LDSC) is advantageous for multiplexing and spreading, research into the design of the code itself is lacking. Furthermore, sidelinks, a key component of 5G Advanced and future generation communication, hold the potential to become stealthy, secure channels for countering jamming attacks. As for machine learning based methods, they are limited in theoretical and simulation, instead of applied to commercial ready codebases. In GPS anti-spoofing, existing solutions are often expensive, bulky, or low in accuracy, while authentication and encryption approaches remain restricted to military use. Furthermore, although distributed mobile spoofer analysis has been theoretically explored, it still lacks real-world implementation studies.
Recognizing the increasing complexity of the wireless landscape, this thesis addresses these open problems through multiple works targeting anti-jamming and anti-spoofing. The first work develops a standard-compliant spread spectrum waveform for NB-IoT applications under jamming. The next focuses on LDSC design, applying it to spreading, and devising methods to obtain sub-optimal LDSC designs against interference. Another work proposes a secure, stealthy sidelink underlay channel and develops interference cancellation methods for flexibility and resilience. In the last work of anti-jamming, a machine learning based interference mitigation solution was proposed, running on open sourced industrial standard, narrowing the gap between academic and real world implementation. On the GPS anti-spoofing front, the first work presents a low-cost, smartphone-based spoofing detection solution matching the accuracy of antenna-array methods. The next work leverages crowdsourcing and sensor fusion, enabling high-accuracy and low-latency anti-spoofing. Finally, the thesis implements conceptual distributed GPS spoofer using low-cost software-defined radios (SDRs), addressing multi-spoofer challenges.
Overall, this work offers vital contributions to the security and resilience of wireless signal transmission. The techniques and solutions presented provide powerful approaches to counteract malicious attacks, fostering reliable communication in an increasingly connected world. Looking ahead, AI and ML hold immense potential for further innovation, bolstering security in 5G and future generation networks. / Doctor of Philosophy / Our phones, cars, navigation systems, and countless other devices rely on invisible wireless signals to work. But what happens when these signals are intentionally disrupted or manipulated? Jamming attacks can cut off vital communication, and spoofing tricks devices into giving false information, leading to mishaps and even security breaches. This research is dedicated to making wireless communication more secure and reliable.
We explored ways to design smarter wireless signals that can resist jamming, even in challenging environments. This includes technologies specifically tuned for smart sensors and other devices within the "Internet of Things," which connects everyday objects to the internet. Additionally, we developed techniques to hide important messages within existing wireless transmissions, making them harder for attackers to detect or disrupt. Finally, we created accessible ways to protect navigation systems (like GPS) from spoofing, helping ensure they give accurate information for safer journeys.
This work aims to protect the wireless systems we use every day from interference and deception. As smart devices continue to fill our world, research like this will become increasingly important to ensure these technologies work safely and reliably. Looking ahead, the next stages of this work will use powerful artificial intelligence to anticipate and neutralize wireless security threats, safeguarding the connected future.
|
114 |
Where fate calls : the HMAS Voyager tragedyFrame, Thomas Robert, History, Australian Defence Force Academy, UNSW January 1991 (has links)
On 10 February 1964 during naval night exercises off the south coast of Australia, the destroyer HMAS Voyager was lost after colliding with the aircraft carrier HMAS Melbourne. 82 men were killed. Following the collision, there were two Royal Commissions that sustained a political controversy that lasted for over four years. This thesis examines the loss of Voyager as a watershed in the operational and administrative history of the RAN and as a major event in Australian national history. This study has four broad objectives: to describe the loss of Voyager and the long running controversy that accompanied the disaster; to offer a convincing explanation of the causes of the collision and why two royal commissions concluded that the causes for the disaster were inexplicable; to assess the effect on the RAN, in terms of specific reforms and its influence on Service culture and professional ethos, of the disaster and the inquiries that followed; and finally, to analyse the loss of Voyager as a media and political cause celebre in Australian history. As so little has been written about Voyager using primary sources, this thesis was committed to detailed description of events as well as analysis of themes. This thesis draws upon an extensive body of primary source material in the form of official naval and Royal Commission records to which complete access was given; several large collections of private papers; over one hundred interviews with principal participants; and comprehensive files of press cuttings. The discussion seeks to demonstrate that a series of naval accidents preceding the loss of Voyager contributed in a substantial way to shaping the public reaction to, and political handling of, the disaster; that the method of inquiry played a major role in generating public and political disquiet; that the collision was both a catalyst and stimulus to change in naval operations and reform in naval administration; that the inability of two Royal Commissions to ascertain the causes of the collision and then to public suspicion of a cover-up; and, that the collision was most probably caused by the incorrect relaying of a tactical signal on the bridge of Voyager. The loss of HMAS Voyager appears to be a key event in the development of the RAN, not as a direct result of the collision or its causes, but as a consequence of its long and controversial aftermath.
|
115 |
Traffic aware resource allocation for multi-antenna OFDM systemsVenkatraman, G. (Ganesh) 14 September 2018 (has links)
Abstract
This thesis focuses on two important challenges in wireless downlink transmission: multi-user (MU) precoder design and scheduling of users over time, frequency, and spatial resources at any given instant. Data streams intended for different users are transmitted by a multiple-input multiple-output (MIMO) multi-antenna orthogonal frequency division multiplexing (OFDM) system. The transmit precoders are designed jointly across space-frequency resources to minimize the number of backlogged packets waiting at the coordinating base stations (BSs), thereby implicitly performing user scheduling.
Then the problem of multicast beamformer design is considered wherein a subset of users belonging to a multicasting group are served by a common group-specific data. The design objective is to either minimize the transmit power for a guaranteed quality-of-service, or to maximize the minimum achievable rate among users for a given transmit power. Unlike existing techniques, the proposed design utilizes both the spatial and frequency resources jointly while designing multi-group beamformers.
As an extension to coordinated precoding, the problem of beamformer design for cloud radio access network is considered wherein beamformers are designed centrally, quantized and sent along with data to the respective BSs via backhaul. Since the users can be served by multiple BSs, beamformer design becomes a nonconvex combinatorial problem. Unlike existing solutions, beamformer overhead is also included in the backhaul utilization along with the associated data. As the number of antennas increases, backhaul utilization is dominated by the beamformers. Thus, to reduce the overhead, two techniques are proposed: varying the quantization precision, and reducing the number of active antennas used for transmission.
Finally, to reduce the complexity involved in the design of joint space- frequency approach, a two-step procedure is proposed, where a MU-MIMO scheduling algorithm is employed to find a subset of users for each scheduling block. The precoders are then designed only for the chosen users, thus reducing the complexity without compromising much on the throughput. In contrast to the null-space-based existing techniques, a low-complexity scheduling algorithm is proposed based on vector projections. The real-time performance of all the schedulers are evaluated by implementing them on both Xilinx ZYNQ-ZC702 system-on-chip (SoC) and TI TCI6636K2H multi-core SoC. / Tiivistelmä
Tässä väitöskirjassa keskitytään kahteen tärkeään langattoman tiedonsiirron haasteeseen alalinkkilähetyksissä: usean käyttäjän (MU) esikooderisuunnitteluun ja käyttäjien skedulointiin aika-, taajuus- ja tilaresurssien yli. Eri käyttäjille tarkoitettuja datavirtoja lähetetään käyttämällä monitulo-monilähtötekniikkaa (MIMO) yhdistettynä monikantoaaltomodulointiin (OFDM). Lähettimien esikooderit suunnitellaan yhteisesti tila- ja taajuusresurssien yli, jotta keskenään yhteistoiminnallisten tukiasemien jonossa olevien pakettien määrää voitaisiin minimoida samalla kun tehdään epäsuorasti käyttäjien skedulointia.
Tämän jälkeen työssä paneudutaan monilähetysten (multicast) keilanmuodostussuunnitteluun, jossa monilähetysryhmään kuuluvien käyttäjien alijoukolle lähetetään yhteistä ryhmäspesifistä dataa. Suunnittelun päämääränä on joko minimoida kokonaislähetysteho tietyllä palvelunlaatuvaatimuksella tai maksimoida pienin saavutettavissa oleva siirtonopeus käyttäjien joukossa tietyllä lähetysteholla. Toisin kuin olemassa olevat menetelmät, ehdotetussa mallissa käytetään yhteisesti sekä aika- että taajuusresursseja usean ryhmän keilanmuodostusta suunniteltaessa.
Laajennuksena yhteistoiminnalliselle esikoodaukselle, väitöskirjassa käsitellään myös keilanmuodostusta pilvipohjaisessa radioliityntäverkkoarkkitehtuurissa. Keilanmuodostajat suunnitellaan keskitetysti, kvantisoidaan ja lähetetään datan mukana tukiasemille käyttäen runkoverkkoyhteyttä. Koska käyttäjiä voidaan palvella usealta tukiasemalta, keilanmuodostussuunnittelu muuttuu ei-konveksiksi kombinatoriseksi ongelmaksi. Toisin kuin olemassa olevissa ratkaisuissa, ehdotettu malli sisällyttää käyttäjien datan lisäksi keilanmuodostajien resursoinnin tarpeen runkoverkkoon. Tukiaseman antennien määrän lisääntyessä, keilanmuodostajien osuus runkoverkon käyttöasteesta kasvaa suureksi. Jotta keilanmuodostajien aiheuttamaa ylimääräistä tiedonsiirtotarvetta voitaisiin minimoida, esitellään kaksi tekniikkaa: kvantisointitarkkuuden muunteleminen sekä lähetykseen käytettävien aktiivisten antennien määrän vähentäminen.
Lopuksi, jotta yhdistetyn tila-taajuussuunnittelun aiheuttamaa kompleksisuutta saataisiin vähennettyä, ehdotetaan kaksivaiheista menetelmää. MU-MIMO skedulointialgoritmin avulla etsitään ensin alijoukko käyttäjiä jokaiselle skedulointilohkolle. Esikooderit suunnitellaan vain valituille käyttäjille, mikä vähentää kompleksisuutta, heikentämättä suorituskykyä kuitenkaan olennaisesti. Poiketen nolla-avaruuteen perustuvista tekniikoista, esitetään yksinkertainen vektoriprojektioihin perustuva skeduleri. Kaikkien skedulerien reaaliaikasuorituskykyä on arvioitu toteuttamalla ne ohjelmoitavilla Xilinx ZYNQ-ZC702 system-on-chip (SoC) ja TI TCI6636K2H moniydinalustoilla.
|
116 |
Proti adaptaci: za transdisciplinaritu a menšinový film / Against adaptation: toward transdisciplinarity and minor cinemaPetříková, Linda January 2014 (has links)
Against Adaptation: Toward Transdisciplinarity and Minor Cinema Linda Petříková Abstract Over the past decades, the field adaptation studies has been trying to break new grounds and escape the confines of the predominant fidelity discourse. This thesis wants to propose new perspectives that have been widely underrepresented, at least in the Anglo-American context, drawing attention to the great relevance to adaptation of the writings of French critical thinkers, most notably Gilles Deleuze and his two-volume publication on cinema and Jacques Rancière and his continuation/reevaluation of Deleuze's film-related concepts. Without directly addressing questions of adaptation, the way both philosophers think about cinema is inseparable from their thinking about literature and indeed about other arts and media, exemplifying new transdisciplinary approaches to adaptation this thesis hopes to encourage. Even though it might seem counterintuitive, considering the efforts of adaptation studies to cut the roots it has grown within literary departments, I chose three Shakespearean adaptations for the case studies as I believe that such focus will enable us to see more clearly the significance of interstices as much as of the links the films form with the text. Jean-Luc-Godard's King Lear, Orson Welles's Chimes at...
|
117 |
Specifické potřeby pacientů při léčbě ran negativním podtlakem / Specific needs of patients during negative pressure wound therapyŠTĚPÁNOVÁ, Hana January 2017 (has links)
The diploma thesis entitled Specific needs of patients during negative pressure wound therapy, consists of two main parts, a theoretical and a practical part. The theoretical part includes findings from research and publications dealing with the issues of wound healing through local application of vacuum therapy, treatment with other methods of wet healing, the impact of long-term non-healing wounds on human needs and the role of the nurse in this scenario. The practical part of the diploma thesis refers to the quantitative research carried out by 46 respondents who were treated with a negative vacuum method, another method of wet healing or a combined form.
|
118 |
Příprava a charakterizace moderních krytů ran / Preparation and characterization of modern wound coversBalášová, Patricie January 2021 (has links)
This diploma thesis is focused on the study of bioactive wound dressings. During the thesis, hydrogel, lyophilized and nanofiber wound dressings were prepared. Hydrogel and lyophilized wound dressings were prepared on basis of two polysaccharides – alginate and chitosan. Nanofiber wound dressings were prepared by spinning polyhydroxybutyrate. All prepared wound dressings were enriched with bioactive substances, which represented analgesics (ibuprofen), antibiotics (ampicillin) and enzymes (collagenase). Into hydrogel and lyophilized wound dressings were all the mentioned active substances incorporated, whereas nanofiber wound dressings were only with ibuprofen and ampicillin prepared. The theoretical part deals with the anatomy and function of human skin. There was explained the process of wound healing and also there were introduced available modern wound dressings. The next chapter of the theoretical part deals with materials for preparing wound dressings (alginate, chitosan, polyhydroxybutyrate) and with active substances, which were used during the experimental part of this thesis. In the theoretical part, the methods of preparation of nanofiber wound dressings and also the methods of cytotoxicity testing used in this work were presented. The first part of the experimental part of this thesis was focused on preparing already mentioned wound dressings. Then, their morphological changes over time and also the gradual release of incorporated active substances into the model environment were monitored. The gradual release of ampicillin was monitored not only spectrophotometrically, but also by ultra-high-performance chromatography. In wound dressings, in which collagenase was incorporated, was also the final proteolytic activity of this enzyme monitored. The effect of the active substances was observed on three selected microorganisms: Escherichia coli, Staphylococcus epidermidis and Candida glabrata. The cytotoxic effect of the active substances on the human keratinocyte cell line was monitored by MTT test and LDH test. A test for monitoring the rate of wound healing – a scratch test – was also performed.
|
119 |
Charakterizace a aplikace mikrovlnného plazmatu pro hojení ran / Characterization and application of microwave plasma on wound healingSmejkalová, Kateřina January 2020 (has links)
The aim of the Master thesis is the investigation of the influence of microwave discharge for skin wound healing. Microwave discharge used for this work was argon microwave plasma generated by the surface wave and direct vortex torch. The theoretical part is focused on basic information about plasma and processes that occur in plasma discharge under specific conditions. Plasma generates various active particles such as hydroxyl radicals, nitric oxide radicals, excited nitrogen molecules, atomic nitrogen, argon and oxygen. All of these particles together with plasma generated photons are usable in biomedical applications and summary of them is shown in the theoretical part. The experimental part is focused on the comparison of torch discharge and microwave plasma generated surface wave in skin wound healing. The model wounds on laboratory mousses were treated by plasma and wound healing was examined during 3 weeks after the plasma treatment. Both plasma systems showed healing acceleration. Application of torch discharge was proved to be the most effective method in the healing of skin defects. Additionally, determination of active particles was taken by optical emission spectroscopy. Based on these measurements, plasma parameters were determined: electron temparutare, rotational and vibrational temperatures. To determine role of different plasma active species, the treatment of indigo coloured artificial skin model was treated under various conditions by both plasma systems. Results show that the direct interaction between plasma particles is the main effect, role of radiation, only, is more or less negligible. Finally, the plasma vortex system was visualized using fast camera at selected powers and gas flows.
|
120 |
Využití plazmové trysky pro hojení ran / Use of plasma jet for wound healingDvořáková, Eva January 2021 (has links)
This diploma thesis was focused on the possibility of using a plasma nozzle to accelerate the wound healing process. The benefits of using low-temperature plasma in medicine or biomedical applications are known from many studies, and low-temperature plasma is already used to sterilize medical devices, materials or surgical instruments. Some studies also report a high potential of usinh plasma nozzle in the treatment of skin wounds. In the experimental part of this work, an in vitro wound healing test was performed using two different low-temperature plasma sources. Source No. 1 was a surface wave microwave discharge and source No. 2 was a torch microwave discharge. An in vitro scratch healing test was performed on a monolayer of HaCaT keratinocytes and testing was performed using various parameters. The influence of the plasma treatment time was monitored, as well as the influence of the plasma discharge power and also the influence of the argon working gas flow. Especially when using a torch microwave discharge, faster wound healing was recorded at most of the parameters used compared to the control. Thus, it can be said that this source appears to be potentially suitable for faster wound healing. Furthermore, in the work using the MTT cytotoxicity test, the viability of skin cells after their plasmination was also monitored using the same conditions as in the in vitro wound healing test. When performed in the standard MTT assay, none of the settings or sources used showed any cytotoxic effects on keratinocytes. LDH cytotoxicity tests were also performed concurrently to verify the accuracy of the MTT assays. The results of both tests agreed and the use of low-temperature plasma in skin treatment can be considered as safe. Overall, the results show that the plasma nozzle can find use in medicine in the healing of skin wounds and chronic defects as a potentially fast, inexpensive and effective method.
|
Page generated in 1.2723 seconds