Wireless Deep Video Semantic Transmission

In this paper, we design a new class of high-efficiency deep joint source-channel coding methods to achieve end-to-end video transmission over wireless channels. The proposed methods exploit nonlinear transform and conditional coding architecture to adaptively extract semantic features across video frames, and transmit semantic feature domain representations over wireless channels via deep joint source-channel coding. Our framework is collected under the name deep video semantic transmission (DVST). In particular, benefiting from the strong temporal prior provided by the feature domain context, the learned nonlinear transform function becomes temporally adaptive, resulting in a richer and more accurate entropy model guiding the transmission of current frame. Accordingly, a novel rate adaptive transmission mechanism is developed to customize deep joint source-channel coding for video sources. It learns to allocate the limited channel bandwidth within and among video frames to maximize the overall transmission performance. The whole DVST design is formulated as an optimization problem whose goal is to minimize the end-to-end transmission rate-distortion performance under perceptual quality metrics or machine vision task performance metrics. Across standard video source test sequences and various communication scenarios, experiments show that our DVST can generally surpass traditional wireless video coded transmission schemes. The proposed DVST framework can well support future semantic communications due to its video content-aware and machine vision task integration abilities.Comment: published in IEEE JSA

Protection against paraquat-induced oxidative stress by Curcuma longa extract-loaded polymeric nanoparticles in zebrafish embryos

The link between oxidative stress and environmental factors plays an important role in chronic degenerative diseases; therefore, exogenous antioxidants could be an effective alternative to combat disease progression and/or most significant symptoms. Curcuma longa L. (CL), commonly known as turmeric, is mostly composed of curcumin, a multivalent molecule described as having antioxidant, anti-inflammatory and neuroprotective properties. Poor chemical stability and low oral bioavailability and, consequently, poor absorption, rapid metabolism, and limited tissue distribution are major restrictions to its applicability. The advent of nanotechnology, by combining nanosacale with multi-functionality and bioavailability improvement, offers an opportunity to overcome these limitations. Therefore, in this work, poly-Ɛ-caprolactone (PCL) nanoparticles were developed to incorporate the methanolic extract of CL, and their bioactivity was assessed in comparison to free or encapsulated curcumin. Their toxicity was evaluated using zebrafish embryos by applying the Fish Embryo Acute Toxicity test, following recommended OECD guidelines. The protective effect against paraquat-induced oxidative damage of CL extract, free or encapsulated in PCL nanoparticles, was evaluated. This herbicide is known to cause oxidative damage and greatly affect neuromotor functions. The overall results indicate that CL-loaded PCL nanoparticles have an interesting protective capacity against paraquat-induced damage, particularly in neuromuscular development that goes well beyond that of CL extract itself and other known antioxidants.Marisa P. Sarria was supported by Marie Skłodowska—Curie Actions from European Union’s 7th Framework Programme for Research, Technological Development and Demonstration under Grant Agreement 600375. This work was supported by the strategic programme UID/BIA/04050/ 2019 funded by national funds through the Fundação para a Ciência e a Tecnologia I.P. Marisa P. Sárria was supported by Marie Curie COFUND funding from the European Union’s 7th Framework Programme for research, technological development, and demonstration under grant agreement 600375. Begoña Espiña is supported by the co-funding from Northern Regional Operational Program through the Project NORTE-45-2015-02 Nanotechnology based functional solutions. B.E. acknowledges the financial support of the project SbDtoolBox—Nanotechnology-based tools and tests for Safer-by-Design nanomaterials, with the reference nº NORTE-01-0145-FEDER-000047, funded by Norte2020—North-Regional Operational Programme under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF)

Multi-scale assessment of land changes in Ethiopia : understanding the impact of human activities on ecosystem services

Remote sensing provides land-cover information on a variety of temporal and spatial scales. The increasing availability of remote sensing data is now a major factor in land-change analysis and in understanding its impact on ecosystem services and biodiversity. This wider accessibility is also leading to improvements in the methods used to integrate these data into land-cover modelling and change analysis. Despite these developments in current technology and data availability however, there are still questions to be addressed regarding the dynamics of land cover and its impact, particularly in areas such as Ethiopia where the human population is expanding and there is a need for improvement in the management of natural resources. Multi-scale approaches (from the national to the local) were used in this thesis to assess change in land cover and ecosystem services in Ethiopia, specifically in terms of provisioning (the production of food, i.e. cash crops) and regulating (climate control for vegetation cover). These assessments were based on multi-scale remote sensing (very high spatial resolution remote aerial sensing, high-resolution SPOT 5 satellite imaging and products of medium-resolution satellite remote sensing) and climate data (e.g., precipitation, temperature). The main focus in this thesis is on mapping and modelling the spatial distribution of vegetation. This includes: (i) forest mapping (indigenous and exotic forests), (ii) modelling the probabilistic presence of understory coffee, (iii) Coffea arabica species distribution modelling and mapping and (iv) simulating pre-agricultural-expansion vegetation cover in Ethiopia. The results of the applied predictive modelling were robust in terms of: (i) identifying and mapping past vegetation cover and (ii) mapping understory shrubs such as coffee plants that grow as understory. I present a reconstruction of earlier vegetation cover that mainly comprised broadleaved evergreen and deciduous forest but was replaced in the course of agricultural expansion. Given the spatial scale of the latter, the environmental modelling was complemented with high spatial resolution satellite (2.5m) and aerial images (0.5m). The results of the Object Based Image Analysis show that indigenous forests were separated from exotic forests. Current and future suitable locations that are environmentally favourable for the growth of understory coffee were identified and mapped in the coffee-growing areas of Ethiopia. In conclusion, the information presented in this thesis, based on the multi-scale assessment of land changes, should lead to the better-informed management of natural resources and conservation, and the restoration of major areas affected by human population growth.Kaukokartoituksen avulla kerätään informaatiota maanpeitteestä ja maankäytöstä eri temporaalisilla ja spatiaalisilla resoluutiolla. Kaukokartoituksella on tärkeä rooli analysoitaessa maankäytön muutosta ja sen vaikutusta ekosysteemipalveluihin ja luonnon monimuotoisuuteen. Huolimatta siitä että kaukokartoitusaineistojen saatavuus on parantunut ja menetelmät kehittyneet, maailmassa on kuitenkin vielä alueita joiden maanpeitteen muutoksen dynamiikkaa ei vielä hyvin tunneta. Tässä väitöskirjatutkimuksessa tutkittiin Etiopian maankäytön muutosta ja sen vaikutusta ekosysteemipalveluihin ja luonnon monimuotoisuuteen usealla eri spatiaalisilla mittakaavoilla (paikallistasolta alueelliselle tasolle). Pääpaino tässä työssä oli kartoittaa ja mallintaa kasvillisuuden alueellista levinneisyyttä hyödyntäen eri erotuskyvyn omaavia kaukokartoitusaineistoja ja erilaisia kaukokartoitusmenetelmiä. Työssä kehitettiin kaukokartoitusperusteisia luokitusmenetelmiä, joilla pystyttiin: (i) erottelemaan tutkimusalueella sijaitsevat alkuperäismetsät istutusmetsistä ja (ii) saadun tiedon avulla edelleen mallintaa alkuperäiskahvin Coffea arabican spatiaalista levinneisyyttä, sillä alkuperäiskahvi kasvaa alkuperäismetsien pensaskerroksessa; (iii) muodostaa bioklimaattisia ja geospatiaalisia muuttujia sisältävän todennäköisyysmallin alkuperäiskahvin levinneisyyden arvioimiseksi muuttuvissa ilmasto-olosuhteissa; sekä (iv) simuloida Etiopian kasvillisuuspeitettä ajalta ennen maanviljelyksen voimakasta leviämistä. Alueellisella tasolla tulokset osoittavat, että Etiopian pinta-alasta ikivihreät metsät ja lehtimetsät ovat peittäneet huomattavasti laajemman alueen kasvillisuuspeitteestä ennen maanviljelyksen voimakasta leviämistä. Paikallistason tutkimuksessa objektipohjaisella kaukokartoitusaineiston luokitusmenetelmällä pystyttiin erottelemaan alkuperäismetsät istutusmetsistä ja edelleen mallintaa alkuperäiskahvin Coffea arabican spatiaalista levinneisyyttä hyödyntäen alkuperäismetsien erottelua, bioklimaattisia ympäristömuuttujia sekä spatiaalis-tilastollisia todennäköisyysmalleja. Yhteenvetona voidaan todeta että tämä väitöskirjatutkimus antaa näkökulmia monimittakaavaisen maankäytönmuutoksen vaikutusten ymmärtämiseksi ekosysteemipalveluihin ja luonnon monimuotoisuuteen. Tämän tutkimuksen tuloksia voidaan hyödyntää esimerkiksi voimakaan väestönkasvun alueilla, joissa tarvitaan tehokkaita menetelmiä luonnonvarojen hallintaan ja ympäristön suojeluun

Electromagnetic fault analysis for high specific power permanent magnet synchronous machine

This thesis discusses the electromagnetic fault analyses for a high specific power 1 MW permanent magnet synchronous electric machine designed for aerospace applications. As the high specific power of 13.3 kW/kg of the machine is to be achieved by pushing the design parameters such as mechanical speed, electric current, and temperature, the importance of permanent magnet demagnetization and long-term insulation quality is stressed. Demagnetization will be quantified using finite element methods, where the effects of permanent magnet material, air gap, and rotor back yoke material on demagnetization will be explored respectively. This is expected to provide insights to the machine designers to select appropriate materials and air gap, topics that have not been yet covered in previous work related with the particular design. Ultimately, this discussion will lead to an electro-thermal trade-off problem since permanent magnets are highly sensitive to temperature. Secondly, this thesis discusses the insulation aging to determine the longevity of the design. Various aging models therefore will be introduced to provide an analytical basis to project the insulation lifetime on real applications. A preliminary aging experimental setup is presented, along with a partial discharge detection setup since partial discharges are suspected to be one of the main electrical aging mechanisms. Ultimately, the data obtained from the experiments must be fitted into the aging models. This thesis will present early experimental results

Stochastic optimization and interactive machine learning for human motion analysis

The analysis of human motion from visual data is a central issue in the computer vision research community as it enables a wide range of applications and it still remains a challenging problem when dealing with unconstrained scenarios and general conditions. Human motion analysis is used in the entertainment industry for movies or videogame production, in medical applications for rehabilitation or biomechanical studies. It is also used for human computer interaction in any kind of environment, and moreover, it is used for big data analysis from social networks such as Youtube or Flickr, to mention some of its use cases. In this thesis we have studied human motion analysis techniques with a focus on its application for smart room environments. That is, we have studied methods that will support the analysis of people behavior in the room, allowing interaction with computers in a natural manner and in general, methods that introduce computers in human activity environments to enable new kind of services but in an unobstrusive mode. The thesis is structured in two parts, where we study the problem of 3D pose estimation from multiple views and the recognition of gestures using range sensors. First, we propose a generic framework for hierarchically layered particle filtering (HPF) specially suited for motion capture tasks. Human motion capture problem generally involve tracking or optimization of high-dimensional state vectors where also one have to deal with multi-modal pdfs. HPF allow to overcome the problem by means of multiple passes through substate space variables. Then, based on the HPF framework, we propose a method to estimate the anthropometry of the subject, which at the end allows to obtain a human body model adjusted to the subject. Moreover, we introduce a new weighting function strategy for approximate partitioning of observations and a method that employs body part detections to improve particle propagation and weight evaluation, both integrated within the HPF framework. The second part of this thesis is centered in the detection of gestures, and we have focused the problem of reducing annotation and training efforts required to train a specific gesture. In order to reduce the efforts required to train a gesture detector, we propose a solution based on online random forests that allows training in real-time, while receiving new data in sequence. The main aspect that makes the solution effective is the method we propose to collect the hard negatives examples while training the forests. The method uses the detector trained up to the current frame to test on that frame, and then collects samples based on the response of the detector such that they will be more relevant for training. In this manner, training is more effective in terms of the number of annotated frames required.L'anàlisi del moviment humà a partir de dades visuals és un tema central en la recerca en visió per computador, per una banda perquè habilita un ampli espectre d'aplicacions i per altra perquè encara és un problema no resolt quan és aplicat en escenaris no controlats. L'analisi del moviment humà s'utilitza a l'indústria de l'entreteniment per la producció de pel·lícules i videojocs, en aplicacions mèdiques per rehabilitació o per estudis bio-mecànics. També s'utilitza en el camp de la interacció amb computadors o també per l'analisi de grans volums de dades de xarxes socials com Youtube o Flickr, per mencionar alguns exemples. En aquesta tesi s'han estudiat tècniques per l'anàlisi de moviment humà enfocant la seva aplicació en entorns de sales intel·ligents. És a dir, s'ha enfocat a mètodes que puguin permetre l'anàlisi del comportament de les persones a la sala, que permetin la interacció amb els dispositius d'una manera natural i, en general, mètodes que incorporin les computadores en espais on hi ha activitat de persones, per habilitar nous serveis de manera que no interfereixin en la activitat. A la primera part, es proposa un marc genèric per l'ús de filtres de partícules jeràrquics (HPF) especialment adequat per tasques de captura de moviment humà. La captura de moviment humà generalment implica seguiment i optimització de vectors d'estat de molt alta dimensió on a la vegada també s'han de tractar pdf's multi-modals. Els HPF permeten tractar aquest problema mitjançant multiples passades en subdivisions del vector d'estat. Basant-nos en el marc dels HPF, es proposa un mètode per estimar l'antropometria del subjecte, que a la vegada permet obtenir un model acurat del subjecte. També proposem dos nous mètodes per la captura de moviment humà. Per una banda, el APO es basa en una nova estratègia per les funcions de cost basada en la partició de les observacions. Per altra, el DD-HPF utilitza deteccions de parts del cos per millorar la propagació de partícules i l'avaluació de pesos. Ambdós mètodes són integrats dins el marc dels HPF. La segona part de la tesi es centra en la detecció de gestos, i s'ha enfocat en el problema de reduir els esforços d'anotació i entrenament requerits per entrenar un detector per un gest concret. Per tal de reduir els esforços requerits per entrenar un detector de gestos, proposem una solució basada en online random forests que permet l'entrenament en temps real, mentre es reben noves dades sequencialment. El principal aspecte que fa la solució efectiva és el mètode que proposem per obtenir mostres negatives rellevants, mentre s'entrenen els arbres de decisió. El mètode utilitza el detector entrenat fins al moment per recollir mostres basades en la resposta del detector, de manera que siguin més rellevants per l'entrenament. D'aquesta manera l'entrenament és més efectiu pel que fa al nombre de mostres anotades que es requereixen

Development of Imaging Fourier-Transform Spectroscopy for the Characterization of Turbulent Jet Flames

Recent advances in computational models to simulate turbulent, reactive flow fields have outpaced the ability to collect highly constraining data--throughout the entire flow field--for validating and improving such models. In particular, the ability to quantify in three dimensions both the mean scalar fields (i.e. temperature & species concentrations) and their respective fluctuation statistics via hyperspectral imaging would be a game-changing advancement in combustion diagnostics, with high impact in both validation and improvement efforts for computational combustion models. This research effort establishes imaging Fourier-transform spectrometry (IFTS) as a valuable tool (which complements laser diagnostics) for the study of turbulent combustion. Specifically, this effort (1) demonstrates that IFTS can be used to quantitatively measure spatially resolved spectra from a canonical turbulent flame; (2) establishes the utility of quantile spectra in first-ever quantitative comparisons between measured and modeled turbulent radiation interaction (TRI); (3) develops a simple onion-peeling-like spectral inversion methodology suitable for estimating radial scalar distributions in axisymmetric, optically-thick flames; (4) builds understanding of quantile spectra and demonstrates proof of concept for their use in estimating scalar fluctuation statistics

고속 시리얼 링크를 위한 고리 발진기를 기반으로 하는 주파수 합성기

학위논문(박사) -- 서울대학교대학원 : 공과대학 전기·정보공학부, 2022. 8. 정덕균.In this dissertation, major concerns in the clocking of modern serial links are discussed. As sub-rate, multi-standard architectures are becoming predominant, the conventional clocking methodology seems to necessitate innovation in terms of low-cost implementation. Frequency synthesis with active, inductor-less oscillators replacing LC counterparts are reviewed, and solutions for two major drawbacks are proposed. Each solution is verified by prototype chip design, giving a possibility that the inductor-less oscillator may become a proper candidate for future high-speed serial links. To mitigate the high flicker noise of a high-frequency ring oscillator (RO), a reference multiplication technique that effectively extends the bandwidth of the following all-digital phase-locked loop (ADPLL) is proposed. The technique avoids any jitter accumulation, generating a clean mid-frequency clock, overall achieving high jitter performance in conjunction with the ADPLL. Timing constraint for the proper reference multiplication is first analyzed to determine the calibration points that may correct the existent phase errors. The weight for each calibration point is updated by the proposed a priori probability-based least-mean-square (LMS) algorithm. To minimize the time required for the calibration, each gain for the weight update is adaptively varied by deducing a posteriori which error source dominates the others. The prototype chip is fabricated in a 40-nm CMOS technology, and its measurement results verify the low-jitter, high-frequency clock generation with fast calibration settling. The presented work achieves an rms jitter of 177/223 fs at 8/16-GHz output, consuming 12.1/17-mW power. As the second embodiment, an RO-based ADPLL with an analog technique that addresses the high supply sensitivity of the RO is presented. Unlike prior arts, the circuit for the proposed technique does not extort the RO voltage headroom, allowing high-frequency oscillation. Further, the performance given from the technique is robust over process, voltage, and temperature (PVT) variations, avoiding the use of additional calibration hardware. Lastly, a comprehensive analysis of phase noise contribution is conducted for the overall ADPLL, followed by circuit optimizations, to retain the low-jitter output. Implemented in a 40-nm CMOS technology, the frequency synthesizer achieves an rms jitter of 289 fs at 8 GHz output without any injected supply noise. Under a 20-mVrms white supply noise, the ADPLL suppresses supply-noise-induced jitter by -23.8 dB.본 논문은 현대 시리얼 링크의 클락킹에 관여되는 주요한 문제들에 대하여 기술한다. 준속도, 다중 표준 구조들이 채택되고 있는 추세에 따라, 기존의 클라킹 방법은 낮은 비용의 구현의 관점에서 새로운 혁신을 필요로 한다. LC 공진기를 대신하여 능동 소자 발진기를 사용한 주파수 합성에 대하여 알아보고, 이에 발생하는 두가지 주요 문제점과 각각에 대한 해결 방안을 탐색한다. 각 제안 방법을 프로토타입 칩을 통해 그 효용성을 검증하고, 이어서 능동 소자 발진기가 미래의 고속 시리얼 링크의 클락킹에 사용될 가능성에 대해 검토한다. 첫번째 시연으로써, 고주파 고리 발진기의 높은 플리커 잡음을 완화시키기 위해 기준 신호를 배수화하여 뒷단의 위상 고정 루프의 대역폭을 효과적으로 극대화 시키는 회로 기술을 제안한다. 본 기술은 지터를 누적 시키지 않으며 따라서 깨끗한 중간 주파수 클락을 생성시켜 위상 고정 루프와 함께 높은 성능의 고주파 클락을 합성한다. 기준 신호를 성공적으로 배수화하기 위한 타이밍 조건들을 먼저 분석하여 타이밍 오류를 제거하기 위한 방법론을 파악한다. 각 교정 중량은 연역적 확률을 기반으로한 LMS 알고리즘을 통해 갱신되도록 설계된다. 교정에 필요한 시간을 최소화 하기 위하여, 각 교정 이득은 타이밍 오류 근원들의 크기를 귀납적으로 추론한 값을 바탕으로 지속적으로 제어된다. 40-nm CMOS 공정으로 구현된 프로토타입 칩의 측정을 통해 저소음, 고주파 클락을 빠른 교정 시간안에 합성해 냄을 확인하였다. 이는 177/223 fs의 rms 지터를 가지는 8/16 GHz의 클락을 출력한다. 두번째 시연으로써, 고리 발진기의 높은 전원 노이즈 의존성을 완화시키는 기술이 포함된 주파수 합성기가 설계되었다. 이는 고리 발진기의 전압 헤드룸을 보존함으로서 고주파 발진을 가능하게 한다. 나아가, 전원 노이즈 감소 성능은 공정, 전압, 온도 변동에 대하여 민감하지 않으며, 따라서 추가적인 교정 회로를 필요로 하지 않는다. 마지막으로, 위상 노이즈에 대한 포괄적 분석과 회로 최적화를 통하여 주파수 합성기의 저잡음 출력을 방해하지 않는 방법을 고안하였다. 해당 프로토타입 칩은 40-nm CMOS 공정으로 구현되었으며, 전원 노이즈가 인가되지 않은 상태에서 289 fs의 rms 지터를 가지는 8 GHz의 클락을 출력한다. 또한, 20 mVrms의 전원 노이즈가 인가되었을 때에 유도되는 지터의 양을 -23.8 dB 만큼 줄이는 것을 확인하였다.1 Introduction 1 1.1 Motivation 3 1.1.1 Clocking in High-Speed Serial Links 4 1.1.2 Multi-Phase, High-Frequency Clock Conversion 8 1.2 Dissertation Objectives 10 2 RO-Based High-Frequency Synthesis 12 2.1 Phase-Locked Loop Fundamentals 12 2.2 Toward All-Digital Regime 15 2.3 RO Design Challenges 21 2.3.1 Oscillator Phase Noise 21 2.3.2 Challenge 1: High Flicker Noise 23 2.3.3 Challenge 2: High Supply Noise Sensitivity 26 3 Filtering RO Noise 28 3.1 Introduction 28 3.2 Proposed Reference Octupler 34 3.2.1 Delay Constraint 34 3.2.2 Phase Error Calibration 38 3.2.3 Circuit Implementation 51 3.3 IL-ADPLL Implementation 55 3.4 Measurement Results 59 3.5 Summary 63 4 RO Supply Noise Compensation 69 4.1 Introduction 69 4.2 Proposed Analog Closed Loop for Supply Noise Compensation 72 4.2.1 Circuit Implementation 73 4.2.2 Frequency-Domain Analysis 76 4.2.3 Circuit Optimization 81 4.3 ADPLL Implementation 87 4.4 Measurement Results 90 4.5 Summary 98 5 Conclusions 99 A Notes on the 8REF 102 B Notes on the ACSC 105박