Artificial Intelligence (AI) Model: Adaptive Neuro-Fuzzy Inference System (ANFIS) for Diagnosis of COVID-19 Influenza

The COVID-19 influenza became a curse on the world. It has been around for two years, so no one needs to make a big introduction of it. It has became a significant challenge around the world. Owing to this, we made dynamic networks using an amalgamating of fuzzy logic and neural networks for the prediction of sufferers of COVID-19. These hybrid networks serve for the assessment of the COVID-19 victims and usefully serve for the assessment of the medical resources needed for future victims. This manuscript proposed Sugeno Adaptive Neuro-Fuzzy Inference System (SANFIS) prediction model for COVID-19 prediction in Andhra Pradesh, India. We gathered data on positive COVID-19 sufferers in Andhra Pradesh for this purpose. The data can be separated into three categories: training set, testing set and checking set. We have utilized Root Mean Square Deviation (RMSD) for prediction precision. If the prediction model has a lower RMSD value, it is regarded as the best forecast. In this study, we concluded that the 3 Triangular MFns for each input were excellent with the extreme precision for all of the districts based on our expertise. In the end, we deployed seven SANFIS replicas in Andhra Pradesh, but we discovered that SANFIS6 and SANFIS7 provided excellent COVID-19 prediction results. These findings will assist the government, healthcare agencies, and medical organizations in planning for future COVID-19 victims' medical requirements. These sorts of Sugeno Adaptive Neuro-Fuzzy Inference System (SANFIS) prediction models based on Artificial Intelligence (AI) will be beneficial in overcoming the COVID-19

저산소 염증성 미세환경의 조절을 위한 다기능성 무기나노입자에 관한 연구

학위논문 (박사)-- 서울대학교 대학원 : 공과대학 화학생물공학부, 2019. 2. 현택환.Due to their unique physicochemical properties, inorganic nanoparticles (NPs) have emerged as novel imaging, diagnostic, and therapeutic agents for the future biomedical field. In particular, hypoxic inflammatory microenvironments, which is often found at disease sites in the body, can be easily controlled using inorganic NPs with various combinations. Catalytic inorganic NPs continuously generate oxygen using intracellular hydrogen peroxide in the hypoxic microenvironment. They can also control the phenotype of macrophages in the inflammatory microenvironment, alleviating the inflammation in inflamed tissues. Moreover, immune cell can be targeted using the NPs functionalized with targeting moieties, enabling the delivery of the functional NPs to inflammatory microenvironments. This thesis describes the applications of multifunctional inorganic NPs for modulation of hypoxic and inflammatory microenvironments. Firstly, biocompatible manganese ferrite NP-anchored mesoporous silica NPs (MFMSNs) were designed to overcome hypoxia, consequently enhancing the therapeutic efficiency of photodynamic therapy (PDT). By exploiting the continuous oxygen-evolving property of manganese ferrite NPs through the Fenton reaction, MFMSNs relieve hypoxic condition using a small amount of NPs and improve therapeutic outcomes of PDT for tumors in vivo. In addition, MFMSNs exhibit T2 contrast effect in magnetic resonance imaging (MRI), allowing in vivo tracking of MFMSNs. Secondly, manganese ferrite and ceria NP-anchored mesoporous silica NPs (MFC-MSNs) that can synergistically scavenge reactive oxygen species (ROS) and produce oxygen for M1 macrophage reduction and M2 macrophage induction for rheumatoid arthritis (RA) treatment. MFC-MSNs exhibited a synergistic effect on O2 generation attributed to hydroxyl complementary reaction of ceria NPs scavenging the intermediate hydroxyl radical generated by manganese ferrite NPs during the Fenton reaction in the process of O2 generation, leading to efficient polarization of M1 to M2 macrophages both in vitro and in vivo. Intra-articular administration of MFC-MSNs to RA-suffering rats alleviated hypoxia, inflammation, and pathological features in the joint. Finally, click reaction-assisted immune cell targeting (CRAIT) strategy was developed to deliver drug-loaded NPs into tumor interiors. Immune cell-targeting CD11b antibodies are modified with trans-cyclooctene to enable biorthogonal click chemistry with mesoporous silica NPs with tetrazines (MSNs-Tz). Sequential injection of modified antibodies and MSNs-Tz at intervals of 24 h results in targeted conjugation of the NPs onto CD11b+ myeloid cells, which serve as active vectors into tumor interiors. It was shown that the CRAIT strategy allows deep tumor penetration of drug-loaded NPs, resulting in enhanced therapeutic efficacy in an orthotopic 4T1 breast tumor model.무기 나노입자는 특유의 우수한 물리화학적 특성으로 인해 미래 생의학 분야의 새로운 이미징, 진단 및 치료제로 각광받고 있다. 특히, 다양한 조합의 무기 나노입자를 이용하면 신체의 질병 부위에서 발견되는 저산소 염증성 미세환경을 쉽게 조절할 수 있다. 촉매 무기 나노입자는 저산소성 환경에서 세포 내의 과산화수소를 이용하여 지속적으로 산소를 생성할 수 있을 뿐만 아니라, 염증성 미세환경에서 대식세포의 표현형을 조절하여 조직의 염증을 완화시킬 수 있다. 또한 표적화 분자가 결합된 기능성 나노입자를 사용하면 면역 세포를 쉽게 표적화 할 수 있어, 염증성 미세환경으로 다양한 기능을 가진 나노입자를 전달할 수 있다. 이 학위 논문에서는 저산소 염증성 미세환경의 조절을 위한 다기능성 무기 나노입자의 응용에 대해 기술하였다. 첫 번째로, 망간 산화철 나노입자와 다공성 실리카 나노입자를 결합하여 종양 내의 저산소증을 완화시키고 암 치료법 중 하나인 광역학 치료법의 효율을 크게 증대시켰다. 망간 산화철 나노입자가 펜톤 반응을 통해 산소를 지속적으로 생성할 수 있다는 특성을 이용하여 종양 세포 내의 저산소 환경을 완화시킬 수 있었다. 또한, 나노입자의 자기적 성질로 인해 자기공명영상 (MRI)을 이용한 생체 내의 추적이 가능하였다. 두 번째로, 망간 산화철 나노입자와 세리아 나노입자의 시너지 효과를 이용해 대식세포의 표현형을 M1 형에서 M2 형으로 유도하여 류마티스 관절염의 치료효과를 확인하였다. 망간 산화철의 펜톤 반응 중에 발생하는 하이드록실 라디칼을 세리아 나노입자가 제거해주는 효과로 인해, 산소 발생과 활성산소 제거를 더욱 효율적으로 실행할 수 있었다. 이를 류마티스 관절염을 앓는 실험 쥐에 투여해 저산소증, 염증의 완화 및 여러 병리학적 특성들이 개선됨을 확인하였다. 마지막으로, 약물이 들어있는 나노입자를 종양 내부로 전달하기 위한 클릭 반응을 이용한 면역 세포 표적화 전략을 개발하였다. 면역 세포를 표적화할 수 있는 CD11b 항체와 다공성 실리카 나노입자에 각각 클릭 반응이 가능한 분자를 결합시켜, 생체 내에서 이들의 클릭 반응을 가능하게 하였다. 24시간 간격으로 항체와 나노입자를 주입하여 면역 세포를 성공적으로 표적화하였고, 이를 이용해 기존의 방법으로는 힘들었던 나노입자의 깊은 종양 조직으로의 침투를 확인하였다. 이 전략을 이용하여 약물이 들어있는 나노입자를 유방암을 앓는 실험 쥐에 투여했을 때 더 효과적으로 종양의 성장을 억제함을 확인하였다.Chapter 1 Introduction: Multifunctional Inorganic Nanoparticles and Their Applications in Hypoxic Inflammatory Microenvironments 1 1.1 Introduction 1 1.2 Overview of Multifunctional Inorganic Nanoparticles 4 1.2.1 Multifunctional Inorganic Nanoparticles for Multimodal Imaging 5 1.2.2 Multifunctional Inorganic Nanoparticles for Theranosis 8 1.3 Multifunctional Inorganic Nanoparticles for Modulation of Hypoxic Inflammatory Microenvironments 12 1.3.1 Hypoxic Tumor Microenvironments 12 1.3.2 Modulation of Hypoxic Tumor Microenvironments for Enhanced Cancer Treatment 17 1.3.3 Macrophage Phenotype Modulation in Inflammatory Microenvironments 25 1.3.4 Inflammatory Cell Recruitment in Inflammatory Tumor Microenvironments 32 1.4 Dissertation Overview 39 1.5 References 42 Chapter 2 Continuously O2-Evolving Manganese Ferrite Nanoparticles for Efficient Photodynamic Therapy in Hypoxic Cancer 50 2.1 Introduction 50 2.2 Experimental Section 55 2.3 Result and Discussion 63 2.4 Conclusion 89 2.5 References 90 Chapter 3 Synergistically O2-Generating Nanoparticles Inducing M2 Polarization of Macrophages for Rheumatoid Arthritis Treatment 94 3.1 Introduction 94 3.2 Experimental Section 100 3.3 Result and Discussion 115 3.4 Conclusion 144 3.5 References 146 Chapter 4 Enhanced Tumor Penetration of Drug-Loaded Nanoparticles by Click Reaction-Assisted Immune Cell Targeting Strategy 153 4.1 Introduction 153 4.2 Experimental Section 160 4.3 Result and Discussion 169 4.4 Conclusion 199 4.5 References 201 Bibliography 206 국문 초록 (Abstract in Korean) 212Docto

A Deep Learning-Based Strategy to Predict Self-Interference in SFN DTT

This article belongs to the Proceedings of The 4th XoveTIC Conference[Abstract] A deep learning-based strategy for the analysis of the self-interference in single frequency networks (SFNs) for digital terrestrial television (DTT) broadcasting is considered. Several laboratory measurements were performed to create a dataset that relates the self-interference parameters and some quality metrics of the resulting received signal. The laboratory setup emulates an SFN scenario with two DTT transmitters. The strongest received signal and the relative values of attenuation and delay between the signals stand for the input parameters. The modulation error ratio (MER) of the strongest received signal, the MER of the resulting signal, and the SFN gain (SFNG) are the output parameters. This dataset is used to train four different multi-layer perceptron (MLP) models to predict accurate maps of interference and signal quality metrics. The considered models are suitable as complements for any multiple frequency network (MFN) coverage software with the capability to return the signal strength and the position data. This way, the SFN self-interference behavior can be predicted by considering only a proper description of the MFN coverage.This work has been funded by the Xunta de Galicia (by grant ED431C 2020/15, and grant ED431G2019/01 to support the CITIC, Centre for Information and Communications Technology Research, from the University System of Galicia), the Agencia Estatal de Investigación of Spain (by grants RED2018-102668-T and PID2019-104958RB-C42) and ERDF funds of the EU (FEDER Galicia 2014–2020 & AEI/FEDER Programs, UE), and the predoctoral grant BES-2017-081955.Xunta de Galicia; ED431C 2020/15Xunta de Galicia; ED431G2019/0

Magnetoelectric Nanoparticles: Paradigm Shift in Biomolecular Diagnostics

Recently discovered multiferroic nanoparticles (MFNs) known as magnetoelectric nanoparticles (MENs) promise to revolutionize next-generation biomedical diagnostic techniques and enable rapid and cost-effective screening of lethal diseases. Due to the quantum-mechanically caused intrinsic magnetoelectric (ME) effect, these nanoparticles display strongly coupled magnetic and electric moments and thus provide a unique pathway to monitor and optionally control intrinsic characteristics of bio organisms via application of external magnetic fields. Due to the ME effect, when placed in the microenvironment of a biomolecular sample, MENs’ magnetic properties change to reflect the molecular nature of the sample. Such an unprecedented intrinsic connection to cells and microorganism’s intrinsic characteristics can pave a way to a new diagnostic paradigm. A novel concept of portable biomolecular screening device based on continuous wave nuclear magnetic resonance is being studied to identify microorganisms like bacteria, virus and cancer cell lines. For the first time, MENs have been used to modify NMR spectra and thus enable identification of different cancer cell lines from each other as well as from their normal counterparts at the sub-cellular level. This approach can be used for both in vitro and in vivo diagnostics. In addition, blood samples of Pulmonary Arterial Hypertension (PAH) patients with severe heart and lung conditions were used to study the activity of MENs with prothrombin, the clotting factor of the blood. MENs has significant interaction with prothrombin. MENS can be used for diagnostics of several diseases associated with blood and cancer and it may be used as a therapeutic agent. The experiment proved that the MENs are safe and nontoxic carriers of therapeutic drugs

Do artificial neural networks provide improved volatility forecasts:Evidence from Asian markets

This paper enters the ongoing volatility forecasting debate by examining the ability of a wide range of Machine Learning methods (ML), and specifically Artificial Neural Network (ANN) models. The ANN models are compared against traditional econometric models for ten Asian markets using daily data for the time period from 12 September 1994 to 05 March 2018. The empirical results indicate that ML algorithms, across the range of countries, can better approximate dependencies compared to traditional benchmark models. Notably, the predictive performance of such deep learning models is superior perhaps due to its ability in capturing long-range dependencies. For example, the Neuro Fuzzy models of ANFIS and CANFIS, which outperform the EGARCH model, are more flexible in modelling both asymmetry and long memory properties. This offers new insights for Asian markets. In addition to standard statistics forecast metrics, we also consider risk management measures including the value-at-risk (VaR) average failure rate, the Kupiec LR test, the Christoffersen independence test, the expected shortfall (ES) and the dynamic quantile test. The study concludes that ML algorithms provide improving volatility forecasts in the stock markets of Asia and suggest that this may be a fruitful approach for risk management.</p

Do artificial neural networks provide improved volatility forecasts:Evidence from Asian markets

This paper enters the ongoing volatility forecasting debate by examining the ability of a wide range of Machine Learning methods (ML), and specifically Artificial Neural Network (ANN) models. The ANN models are compared against traditional econometric models for ten Asian markets using daily data for the time period from 12 September 1994 to 05 March 2018. The empirical results indicate that ML algorithms, across the range of countries, can better approximate dependencies compared to traditional benchmark models. Notably, the predictive performance of such deep learning models is superior perhaps due to its ability in capturing long-range dependencies. For example, the Neuro Fuzzy models of ANFIS and CANFIS, which outperform the EGARCH model, are more flexible in modelling both asymmetry and long memory properties. This offers new insights for Asian markets. In addition to standard statistics forecast metrics, we also consider risk management measures including the value-at-risk (VaR) average failure rate, the Kupiec LR test, the Christoffersen independence test, the expected shortfall (ES) and the dynamic quantile test. The study concludes that ML algorithms provide improving volatility forecasts in the stock markets of Asia and suggest that this may be a fruitful approach for risk management.</p

Autonomous capillary systems for life science research and medical diagnostics

In autonomous capillary systems (CS) minute amounts of liquid are transported owing to capillary forces. Such CSs are appealing due to their portability, flexibility, and the exceptional physical behavior of liquids in micrometer sized microchannels, in particular, capillarity and short diffusion times. CSs have shown to be a promising technology for miniaturized immunoassays in life science research and diagnostics. Building on existing experimental demonstrations of immunoassays in CSs, a theoretical model of such immunoassays is implemented, tools and CSs for performing immunoassays are developed, key functional elements of CSs such as capillary pumps and valves are explored experimentally, and a proof-of-concept of the ultimate goal of one-step immunoassays are given in this work. For the theoretical modeling of immunoassays in CSs a finite difference algorithm is applied to delineate the role of the transport of analyte molecules in the microchannel (convection and diffusion), the kinetics of binding between the analyte and the capture antibodies, and the surface density of the capture antibody on the assay. The model shows that assays can be greatly optimized by varying the flow velocity of the solution of analyte in the microchannels. The model also shows how much the analyte-antibody binding constant and the surface density of the capture antibodies influence the performance of the assay. We derive strategies to optimize assays toward maximal sensitivity, minimal sample volume requirement or fast performance. A method using evaporation for controlling the flow rate in CSs was developed for maximum flexibility for developing assays. The method allows to use small CSs that initially are filled by capillary forces and then provide a well defined area of the liquid-air interface from which liquid can evaporate. Temperature and humidity are continuously measured and Peltier-elements are used to adjust the temperatures in multiple areas of the CSs relative to the dew-point. Thereby flow rates in the range from ~1.2 nL s−1 to ~30 pL s−1 could be achieved in the microchannels. This method was then used for screening cells for surface receptors. CSs, that do not need any peripherals for controlling flow rates become even more appealing. We explored the filling behavior of such CSs having microchannels of various length and large capillary pumps. The capillary pumps comprise microstructures of various sizes and shapes, which are spaced to encode certain capillary pressures. The spacing and shape of the microstructures is also used to orient the filling front to obtain a reliable filling behavior and to minimize the risk of entrapping air. We show how two capillary pumps having different hydrodynamic properties can be connected to program a sequence of slow and fast flow rates in CSs. Liquid filling CSs can hardly be stopped, but in some cases it might be beneficial to do so. In a separate chapter we explore how microstructures need to be designed to use capillary forces to stop, time, or trigger liquids. Besides well-defined flow rates in CSs accurately patterned capture antibodies (cAbs) are key for performing high-sensitive surface immunoassays in CSs. We present a method compatible with mass fabrication for patterning cAbs in dense lines of up to 8 lines per millimeter. These cAbs are used with CSs that are optimized for convenient handling, pipetting of solutions, pumping of liquids such as human serum, and visualization of signals for fluorescence immunoassays to detect c-reactive protein (CRP) with a sensitivity of 0.9 ng mL−1 (7.8 pM) from 1 uL of CRP-spiked human serum, within 11 minutes, with 4 pipetting steps, and a total volume of sample and reagents of <1.5 uL. CSs for diagnostic applications have different requirements than CSs that are used as a research tool in life sciences, where a high flexibility and performance primes over the ease of use and portability of the CSs. We give a proof-of-concept for one-step immunoassays based on CSs which we think can be the base for developing portable diagnostics for point-of-care applications. All reagents are preloaded in the CSs. A sample loaded in the CSs redissolves and reconstitutes the detection antibodies (dAbs), analyte-dAb-complexes are formed and detected downstream in the CSs. A user only needs to load a sample and measure the result using a fluorescence microscope or scanner. C-reactive protein was detected in human serum at clinical concentrations within 10 minutes and using only 2 uL of sample

Making the digital markets act more resilient and effective

Aiming to improve the European Commission’s Digital Markets Act proposal as it continues to be scrutinised and refined, CERRE has prepared four issue papers and a subsequent set of recommendations for the Digital Markets Act

DVB-NGH: the Next Generation of Digital Broadcast Services to Handheld Devices

This paper reviews the main technical solutions adopted by the next-generation mobile broadcasting standard DVB-NGH, the handheld evolution of the second-generation digital terrestrial TV standard DVB-T2. The main new technical elements introduced with respect to DVB-T2 are: layered video coding with multiple physical layer pipes, time-frequency slicing, full support of an IP transport layer with a dedicated protocol stack, header compression mechanisms for both IP and MPEG-2 TS packets, new low-density parity check coding rates for the data path (down to 1/5), nonuniform constellations for 64 Quadrature Amplitude Modulation (QAM) and 256QAM, 4-D rotated constellations for Quadrature Phase Shift Keying (QPSK), improved time interleaving in terms of zapping time, end-to-end latency and memory consumption, improved physical layer signaling in terms of robustness, capacity and overhead, a novel distributed multiple input single output transmit diversity scheme for single-frequency networks (SFNs), and efficient provisioning of local content in SFNs. All these technological solutions, together with the high performance of DVB-T2, make DVB-NGH a real next-generation mobile multimedia broadcasting technology. In fact, DVB-NGH can be regarded the first third-generation broadcasting system because it allows for the possibility of using multiple input multiple output antenna schemes to overcome the Shannon limit of single antenna wireless communications. Furthermore, DVB-NGH also allows the deployment of an optional satellite component forming a hybrid terrestrial-satellite network topology to improve the coverage in rural areas where the installation of terrestrial networks could be uneconomical.Gómez Barquero, D.; Douillard, C.; Moss, P.; Mignone, V. (2014). DVB-NGH: the Next Generation of Digital Broadcast Services to Handheld Devices. IEEE Transactions on Broadcasting. 60(2):246-257. doi:10.1109/TBC.2014.2313073S24625760

Improved Spectrum Usage with Multi-RF Channel Aggregation Technologies for the Next-Generation Terrestrial Broadcasting

[EN] Next-generation terrestrial broadcasting targets at enhancing spectral efficiency to overcome the challenges derived from the spectrum shortage as a result of the progressive allocation of frequencies - the so-called Digital Dividend - to satisfy the growing demands for wireless broadband capacity. Advances in both transmission standards and video coding are paramount to enable the progressive roll-out of high video quality services such as HDTV (High Definition Televison) or Ultra HDTV. The transition to the second generation European terrestrial standard DVB-T2 and the introduction of MPEG-4/AVC video coding already enables the transmission of 4-5 HDTV services per RF (Radio Frequency) channel. However, the impossibility to allocate higher bit-rate within the remaining spectrum could jeopardize the evolution of the DTT platforms in favour of other high-capacity systems such as the satellite or cable distribution platforms. Next steps are focused on the deployment of the recently released High Efficiency Video Coding (HEVC) standard, which provides more than 50% coding gain with respect to AVC, with the next-generation terrestrial standards. This could ensure the competitiveness of the DTT. This dissertation addresses the use of multi-RF channel aggregation technologies to increase the spectral efficiency of future DTT networks. The core of the Thesis are two technologies: Time Frequency Slicing (TFS) and Channel Bonding (CB). TFS and CB consist in the transmission of the data of a TV service across multiple RF channels instead of using a single channel. CB spreads data of a service over multiple classical RF channels (RF-Mux). TFS spreads the data by time-slicing (slot-by-slot) across multiple RF channels which are sequentially recovered at the receiver by frequency hopping. Transmissions using these features can benefit from capacity and coverage gains. The first one comes from a more efficient statistical multiplexing (StatMux) for Variable Bit Rate (VBR) services due to a StatMux pool over a higher number of services. Furthermore, CB allows increasing service data rate with the number of bonded RF channels and also advantages when combined with SVC (Scalable Video Coding). The coverage gain comes from the increased RF performance due to the reception of the data of a service from different RF channels rather that a single one that could be, eventually, degraded. Robustness against interferences is also improved since the received signal does not depend on a unique potentially interfered RF channel. TFS was firstly introduced as an informative annex in DVB-T2 (not normative) and adopted in DVB-NGH (Next Generation Handheld). TFS and CB are proposed for inclusion in ATSC 3.0. However, they have never been implemented. The investigations carried out in this dissertation employ an information-theoretical approach to obtain their upper bounds, physical layer simulations to evaluate the performance in real systems and the analysis of field measurements that approach realistic conditions of the network deployments. The analysis report coverage gains about 4-5 dB with 4 RF channels and high capacity gains already with 2 RF channels. This dissertation also focuses on implementation aspects. Channel bonding receivers require one tuner per bonded RF channel. The implementation of TFS with a single tuner demands the fulfilment of several timing requirements. However, the use of just two tuners would still allow for a good performance with a cost-effective implementation by the reuse of existing chipsets or the sharing of existing architectures with dual tuner operation such as MIMO (Multiple Input Multiple Output).[ES] La televisión digital terrestre (TDT) de última generación está orientada a una necesaria mejora de la eficiencia espectral con el fin de abordar los desafíos derivados de la escasez de espectro como resultado de la progresiva asignación de frecuencias - el llamado Dividendo Digital - para satisfacer la creciente demanda de capacidad para la banda ancha inalámbrica. Los avances tanto en los estándares de transmisión como de codificación de vídeo son de suma importancia para la progresiva puesta en marcha de servicios de alta calidad como la televisión de Ultra AD (Alta Definición). La transición al estándar europeo de segunda generación DVB-T2 y la introducción de la codificación de vídeo MPEG-4 / AVC ya permite la transmisión de 4-5 servicios de televisión de AD por canal RF (Radiofrecuencia). Sin embargo, la imposibilidad de asignar una mayor tasa de bit sobre el espectro restante podría poner en peligro la evolución de las plataformas de TDT en favor de otros sistemas de alta capacidad tales como el satélite o las distribuidoras de cable. El siguiente paso se centra en el despliegue del reciente estándar HEVC (High Efficiency Video Coding), que ofrece un 50% de ganancia de codificación con respecto a AVC, junto con los estándares terrestres de próxima generación, lo que podría garantizar la competitividad de la TDT en un futuro cercano. Esta tesis aborda el uso de tecnologías de agregación de canales RF que permitan incrementar la eficiencia espectral de las futuras redes. La tesis se centra en torno a dos tecnologías: Time Frequency Slicing (TFS) y Channel Bonding (CB). TFS y CB consisten en la transmisión de los datos de un servicio de televisión a través de múltiples canales RF en lugar de utilizar un solo canal. CB difunde los datos de un servicio a través de varios canales RF convencionales formando un RF-Mux. TFS difunde los datos a través de ranuras temporales en diferentes canales RF. Los datos son recuperados de forma secuencial en el receptor mediante saltos en frecuencia. La implementación de estas técnicas permite obtener ganancias en capacidad y cobertura. La primera de ellas proviene de una multiplexación estadística (StatMux) de servicios de tasa variable (VBR) más eficiente. Además, CB permite aumentar la tasa de pico de un servicio de forma proporcional al número de canales así como ventajas al combinarla con codificación de vídeo escalable. La ganancia en cobertura proviene de un mejor rendimiento RF debido a la recepción de los datos de un servicio desde diferentes canales en lugar uno sólo que podría estar degradado. Del mismo modo, es posible obtener una mayor robustez frente a interferencias ya que la recepción o no de un servicio no depende de si el canal que lo alberga está o no interferido. TFS fue introducido en primer lugar como un anexo informativo en DVB-T2 (no normativo) y posteriormente fue adoptado en DVB-NGH (Next Generation Handheld). TFS y CB han sido propuestos para su inclusión en ATSC 3.0. Aún así, nunca han sido implementados. Las investigaciones llevadas a cabo en esta Tesis emplean diversos enfoques basados en teoría de la información para obtener los límites de ganancia, en simulaciones de capa física para evaluar el rendimiento en sistemas reales y en el análisis de medidas de campo. Estos estudios reportan ganancias en cobertura en torno a 4-5 dB con 4 canales e importantes ganancias en capacidad aún con sólo 2 canales RF. Esta tesis también se centra en los aspectos de implementación. Los receptores para CB requieren un sintonizador por canal RF agregado. La implementación de TFS con un solo sintonizador exige el cumplimiento de varios requisito temporales. Sin embargo, el uso de dos sintonizadores permitiría un buen rendimiento con una implementación más rentable con la reutilización de los actuales chips o su introducción junto con las arquitecturas existentes que operan con un doble sintonizador tales como[CA] La televisió digital terrestre (TDT) d'última generació està orientada a una necessària millora de l'eficiència espectral a fi d'abordar els desafiaments derivats de l'escassetat d'espectre com a resultat de la progressiva assignació de freqüències - l'anomenat Dividend Digital - per a satisfer la creixent demanda de capacitat per a la banda ampla sense fil. Els avanços tant en els estàndards de transmissió com de codificació de vídeo són de la màxima importància per a la progressiva posada en marxa de serveis d'alta qualitat com la televisió d'Ultra AD (Alta Definició). La transició a l'estàndard europeu de segona generació DVB-T2 i la introducció de la codificació de vídeo MPEG-4/AVC ja permet la transmissió de 4-5 serveis de televisió d'AD per canal RF (Radiofreqüència). No obstant això, la impossibilitat d'assignar una major taxa de bit sobre l'espectre restant podria posar en perill l'evolució de les plataformes de TDT en favor d'altres sistemes d'alta capacitat com ara el satèl·lit o les distribuïdores de cable. El següent pas se centra en el desplegament del recent estàndard HEVC (High Efficiency Vídeo Coding), que oferix un 50% de guany de codificació respecte a AVC, junt amb els estàndards terrestres de pròxima generació, la qual cosa podria garantir la competitivitat de la TDT en un futur pròxim. Aquesta tesi aborda l'ús de tecnologies d'agregació de canals RF que permeten incrementar l'eficiència espectral de les futures xarxes. La tesi se centra entorn de dues tecnologies: Time Frequency Slicing (TFS) i Channel Bonding (CB). TFS i CB consistixen en la transmissió de les dades d'un servei de televisió a través de múltiples canals RF en compte d'utilitzar un sol canal. CB difon les dades d'un servei a través d'uns quants canals RF convencionals formant un RF-Mux. TFS difon les dades a través de ranures temporals en diferents canals RF. Les dades són recuperades de forma seqüencial en el receptor per mitjà de salts en freqüència. La implementació d'aquestes tècniques permet obtindre guanys en capacitat i cobertura. La primera d'elles prové d'una multiplexació estadística (StatMux) de serveis de taxa variable (VBR) més eficient. A més, CB permet augmentar la taxa de pic d'un servei de forma proporcional al nombre de canals així com avantatges al combinar-la amb codificació de vídeo escalable. El guany en cobertura prové d'un millor rendiment RF a causa de la recepció de les dades d'un servei des de diferents canals en lloc de només un que podria estar degradat. De la mateixa manera, és possible obtindre una major robustesa enfront d'interferències ja que la recepció o no d'un servei no depén de si el canal que l'allotja està o no interferit. TFS va ser introduït en primer lloc com un annex informatiu en DVB-T2 (no normatiu) i posteriorment va ser adoptat en DVB-NGH (Next Generation Handheld). TFS i CB han sigut proposades per a la seva inclusió en ATSC 3.0. Encara així, mai han sigut implementades. Les investigacions dutes a terme en esta Tesi empren diverses vessants basades en teoria de la informació per a obtindre els límits de guany, en simulacions de capa física per a avaluar el rendiment en sistemes reals i en l'anàlisi de mesures de camp. Aquestos estudis reporten guanys en cobertura entorn als 4-5 dB amb 4 canals i importants guanys en capacitat encara amb només 2 canals RF. Esta tesi també se centra en els aspectes d'implementació. Els receptors per a CB requerixen un sintonitzador per canal RF agregat. La implementació de TFS amb un sol sintonitzador exigix el compliment de diversos requisit temporals. No obstant això, l'ús de dos sintonitzadors permetria un bon rendiment amb una implementació més rendible amb la reutilització dels actuals xips o la seua introducció junt amb les arquitectures existents que operen amb un doble sintonitzador com ara MIMO (Multiple Input Multiple Output).Giménez Gandia, JJ. (2015). Improved Spectrum Usage with Multi-RF Channel Aggregation Technologies for the Next-Generation Terrestrial Broadcasting [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/52520TESI