Social networks are popular platforms that simplify user interaction and encourage collaboration. They collect large amounts of media from their users, often reported from mobile devices. The value and impact of social media makes it however an attractive attack target. In this thesis, we focus on the following social media vulnerabilities. First, review centered social networks such as Yelp and Google Play have been shown to be the targets of significant search rank and malware proliferation attacks. Detecting fraudulent behaviors is thus paramount to prevent not only public opinion bias, but also to curb the distribution of malware. Second, the increasing use of mobile visual data in news networks, authentication and banking applications, raises questions of its integrity and credibility. Third, through proof-of- concept implementations, we show that data reported from wearable personal trackers is vulnerable to a wide range of security and privacy attacks, while off-the-shelves security solutions do not port gracefully to the constraints introduced by trackers. In this thesis we propose novel solutions to address these problems. First, we introduce Marco, a system that leverages the wealth of spatial, temporal and network information gleaned from Yelp, to detect venues whose ratings are impacted by fraudulent reviews. Second, we propose FairPlay, a system that correlates review activities, linguistic and behavioral signals gleaned from longitudinal app data, to identify not only search rank fraud but also malware in Google Play, the most popular Android app market. Third, we describe Movee, a motion sensor based video liveness verification system, that analyzes the consistency between the motion inferred from the simultaneously and independently captured camera and inertial sensor streams. Finally, we devise SensCrypt, an efficient and secure data storage and communication protocol for affordable and lightweight personal trackers. We provide the correctness and efficacy of our solutions through a detailed theoretic and experimental analysis.

<p> </p><div> <div> <div> <p> </p><div> <div> <div> <p> </p><div> <div> <div> <p>The current state of the art in biopotential recordings rely on radiative electromagnetic (EM) fields. In such transmissions, only a small fraction of this energy is received since the EM fields are widely radiated resulting in lossy inefficient systems. Using the body as a communication medium (similar to a ’wire’) allows for the containment of the energy within the body, yielding order(s) of magnitude lower energy than radiative EM communication. The first part of this work introduces Animal Body Communication for untethered rodent biopotential recording and for the first time this work develops the theory and models for animal body communication circuitry and channel loss. In vivo experimental analysis proves that ABC successfully transmits acquired electrocardiogram (EKG) signals through the body with correlation greater than 99% when compared to traditional wireless communication modalities, with a 50x reduction in power consumption. The second part of this work focusses on the analysis and design of an Electro-Quasistatic Human Body Communication (EQS-HBC) system for simultaneous sensing and transmission of biopotential signals. In this work, detailed analysis on the system level interaction between the sensing and transmitting circuitry is studied and a design to enable simultaneous sensing and transmission is proposed. Experimental analysis was performed to understand the interaction between the Right Leg-Drive circuitry and the HBC transmission along with the effect of the ADC quantization on signal quality. Finally, experimental trials proves that EKG signals can be transmitted through the body with greater than 96% correlation when compared to Bluetooth systems at extremely low powers. </p> </div> </div> </div> </div> </div> </div> </div> </div> </div>

Previous studies have used accelerometers with various operating ranges (ORs) when measuring biomechanical parameters. However, it is still unclear whether ORs influence the accuracy of running parameters, and whether the different stiffnesses of footwear midsoles influence this accuracy. The purpose of the present study was to systematically investigate the influence of OR on the accuracy of stride length, running velocity, and on peak tibial acceleration. Twenty-one recreational heel strike runners ran on a 15-m indoor track at self-selected running speeds in three footwear conditions (low to high midsole stiffness). Runners were equipped with an inertial measurement unit (IMU) affixed to the heel cup of the right shoe and with a uniaxial accelerometer at the right tibia. Accelerometers (at the tibia and included in the IMU) with a high OR of ±70 g were used as the reference and the data were cut at ±32, ±16, and at ±8 g in post-processing, before calculating parameters. The results show that the OR influenced the outcomes of all investigated parameters, which were not influenced by tested footwear conditions. The lower ORs were associated with an underestimation error for all biomechanical parameters, which increased noticeably with a decreasing OR. It can be concluded that accelerometers with a minimum OR of ±32 g should be used to avoid inaccurate measurements.

No description available.

Home-based exercise is a popular physical activity of maintaining fitness, health andwellness in general. However, without proper supervision and basic knowledge of theexercises in the workout plan, there is an increased risk of injury. Considering that noteveryone is willing to attend crowded gyms or schedule professional personal trainingsessions, in this study, a novel feedback system is proposed, in the form of a mobileapplication. Accelerometer and gyroscope data were collected from 10 volunteersperforming 3 exercises, squats, lunges and bridges, with inertial sensors attachedto their back lumbar region, on both shanks and on both thighs. Each participantperformed 5 repetitions of the correct technique and 5 repetitions of 4 mistakes foreach exercise. The accuracies of 3 classifiers, a SVM, a RF and DT were comparedwith the SVM performing the best across all 3 exercises. The best location and numberof sensors was determined by examining the accuracy of a SVM model for 15 uniquemulti-sensor configurations. The best performing setup, being the configuration with 2sensors, one at the lumbar area and one at the shank, was used in exploring the efficacyof different data processing techniques. Time-domain statistical features, sensor angletimeseries and the filtered signal timeseries were evaluated as input to a NN. The timedomainfeatures performed the best achieving the highest accuracy in all 3 exercises,with an accuracy of 67% for the squats, 87% for the lunges and 75% for the hip bridges.Overall, the final model demonstrated promising capabilities of classifying exercisetechnique of basic lower-body exercises, with a real-time feedback implementationbeing a feasible solution for self-efficient fitness. / Hemmaträning är en populär typ av fysisk aktivitet för att upprätthålla kondition,hälsa och välbefinnande. Dock utan övervakning och basal kunskap om hur olikaövningar bör utföras så finns det en ökad risk för skador. Alla människor går intefrivilligt till trånga och fullsatta gym eller bokar in pass med personlig tränare. Därförföreslås i denna studie ett nytt återkopplingssytem vid träning som kan användas via enmobilapp. Data från en accelerometer och ett gyroskop har samlats in från tio frivilligapersoner. De har utfört tre olika styrkeövningar; knäböj, utfallssteg och höftlyft medtröghetssensorer placerade på deras ländrygg, på underbenen och på låren. Varjedeltagare utförde fem repetitioner med korrekt teknik och sedan fem repetitionermed fyra olika typer av felaktig teknik för varje styrkeövning. Noggrannheten förtre klassificerare, SVM, RF och DT jämfördes sedan med det SVM som presteradebäst i alla tre styrkeövningarna. Det optimala antalet sensorer tillsammans med bästplacering av dessa räknades ut genom att undersöka en SVM modell med 15 unikamultisensorkonfigurationer. Det visade sig att kombinationen med två sensorer, envid ländryggen och en på underbenet var den bästa och därför användes den föratt undersöka effektiviteten av olika databehandlingstekniker. Tidsdomänsstatistiskafunktioner, sensorvinkeltidsserier och filtrerade signaltidsserier utvärderades sominmatning till ett NN. Tidsdomänsfunktionerna presterade bäst och uppnådde högstnoggrannhet i alla tre övningarna. Detta med ett korrekt utfall av 67% för knöböj,87% för utfallsteg och 75% för höftlyft. Sammantaget visade den slutliga modellenen lovande förmåga att klassificera träningsteknik för basala styrkeövningar för nedredelen av kroppen. Samtidigt som användaren får feedback i realtid vilket gör detmöjligt att utföra effektiv träning själv hemma.

This thesis, written by Ingrid Öberg Månsson at KTH Royal Institute of Technology and entitled “Electroanalytical devices with fluidic control using textile materials and methods”, presents experimental studies on the development of textile based electronic devices and biosensors. One of the reasons why this is of interest is the growing demand for integrated smart products for wearable health monitoring or energy harvesting. To enable such products, new interdisciplinary fields arise combining traditional textile technology and electronics. Textile based devices have garnered much interest in recent years due to their innate ability to incorporate function directly into, for example, clothing or bandages by textile processes such as weaving, knitting or stitching. However, many modifications of yarns required for such applications are not available on an industrial scale. The major objective of this work has been to study how to achieve the performance necessary to create electronic textile devices by either coating yarns with conductive material or using commercially available conductive yarns that are functionalized to create sensing elements. Further, liquid transport within textile materials has been studied to be able to control the contact area between electrolyte and electrodes in electrochemical devices such as sensors and transistors. Yarns with specially designed cross-sections, traditionally used in sportswear to wick sweat away from the body and enhance evaporation, was used to transport electrolyte liquids to come in contact with yarn electrodes. The defined area of the junction where the fluidic yarn meets the conductive yarn was shown to increase stability of the measurements and the reproducibility between devices. The results presented in the two publications of this thesis as well as additional results presented in the thesis itself show the promising potential of using textile materials to integrate electronic and electrochemical functionality in our everyday life. This is shown by using basic textile materials and processing techniques to fabricate complex devices for various application areas such as sensors and diagnostics as well as electrical and energy harvesting components. / Denna avhandling, skriven av Ingrid Öberg Månsson vid Kungliga Tekniska Högskolan och titulerad ”Elektroanalytiska sensorer med vätskekontroll integrerad genom användande av textila material och metoder”, presenterar experimentella studier inom utvecklingen av textilbaserade elektroniska komponenter och biosensorer. Detta är av intresse på grund av den ökade efterfrågan på integrerade smarta produkter som till exempel bärbara sensorer för hälsoövervakning eller för att samla upp och konvertera energi till elektricitet. För att möjliggöra denna typ av produkter föds nya interdisciplinära fält där traditionell textilteknologi och elektronik möts. Textilbaserade enheter har väckt stort intresse under de senaste åren på grund av den naturliga förmågan att integrera funktion i till exempel kläder eller förband genom textila tillverkningsprocesser som väveri, stickning eller sömnad. Många modifikationer hos garner som krävs för att möjliggöra sådana tillämpningar är dock inte tillgängliga i större skala. Därför har det huvudsakliga syftet med denna studie varit att undersöka hur man kan uppnå den prestanda som krävs för att tillverka elektroniska textila komponenter, antingen genom att belägga garner med elektroniskt ledande material eller genom att använda kommersiellt tillgängliga ledande garner som sedan modifieras kemiskt för att skapa sensorer. Utöver detta har vätsketransport inom textila material studerats för att kunna styra och kontrollera kontaktytan mellan elektrolyt och elektroder i elektrokemiska enheter så som sensorer och transistorer. Garner med speciella tvärsnitt, som traditionellt använts i sportkläder för att transportera svett bort från kroppen och underlätta avdunstning, har använts för att transportera elektrolytvätska till elektroder av garn. Den definierade kontaktytan där det vätsketransporterade garnet korsar elektrodgarnet har visats öka stabiliteten av mätningen och reproducerbarheten mellan mätenheter. Resultaten som presenteras i de två artiklar som denna avhandling bygger på samt i avhandlingen själv visar på lovande potential för användandet av textila material för att integrera elektronisk och elektrokemisk funktionalitet i våra vardagsliv. Detta har uppnåtts genom att använda grundläggande textila material och tillverkningsprocesser för att tillverka komplexa enheter för olika tillämpningsområden så som sensorer för diagnostik samt elektroniska komponenter. / <p>QC 2020-08-21</p>

A constantly growing corpus of interdisciplinary studies support the idea that music is a complex multimodal medium that is experienced not only by means of sounds but also through body movement. From this perspective, musical instruments can be seen as technological objects coupled with a repertoire of performance gestures. This repertoire is part of an ecological knowledge shared by musicians and listeners alike. It is part of the engine that guides musical experience and has a considerable expressive potential. This thesis explores technical and conceptual issues related to the analysis and creative use of music-related body movements in instrumental music performance. The complexity of this subject required an interdisciplinary approach, which includes the review of multiple theoretical accounts, quantitative and qualitative analysis of data collected in motion capture laboratories, the development and implementation of technologies for the interpretation and interactive use of motion data, and the creation of short musical pieces that actively employ the movement of the performers as an expressive musical feature. The theoretical framework is informed by embodied and enactive accounts of music cognition as well as by systematic studies of music-related movement and expressive music performance. The assumption that the movements of a musician are part of a shared knowledge is empirically explored through an experiment aimed at analysing the motion capture data of a violinist performing a selection of short musical excerpts. A group of subjects with no prior experience playing the violin is then asked to mime a performance following the audio excerpts recorded by the violinist. Motion data is recorded, analysed, and compared with the expert’s data. This is done both quantitatively through data analysis xii as well as qualitatively by relating the motion data to other high-level features and structures of the musical excerpts. Solutions to issues regarding capturing and storing movement data and its use in real-time scenarios are proposed. For the interactive use of motion-sensing technologies in music performance, various wearable sensors have been employed, along with different approaches for mapping control data to sound synthesis and signal processing parameters. In particular, novel approaches for the extraction of meaningful features from raw sensor data and the use of machine learning techniques for mapping movement to live electronics are described. To complete the framework, an essential element of this research project is the com- position and performance of études that explore the creative use of body movement in instrumental music from a Practice-as-Research perspective. This works as a test bed for the proposed concepts and techniques. Mapping concepts and technologies are challenged in a scenario constrained by the use of musical instruments, and different mapping ap- proaches are implemented and compared. In addition, techniques for notating movement in the score, and the impact of interactive motion sensor systems in instrumental music practice from the performer’s perspective are discussed. Finally, the chapter concluding the part of the thesis dedicated to practical implementations describes a novel method for mapping movement data to sound synthesis. This technique is based on the analysis of multimodal motion data collected from multiple subjects and its design draws from the theoretical, analytical, and practical works described throughout the dissertation. Overall, the parts and the diverse approaches that constitute this thesis work in synergy, contributing to the ongoing discourses on the study of musical gestures and the design of interactive music systems from multiple angles.

Smarta kläder är en kroppsnära teknik som består av kläder som har i sig integrerade/invävda sensorer vilka mäter kroppssignaler, arbetsställningar och rörelser och visar information om eventuella överbelastningar. Syftet i denna studie var att utvärdera prototyp 1 av ett smart arbetsklädersystem genom att utreda användarnas upplevelse (user experience) och användbarhet av prototypen samt prototypens påverkan på testpersonernas arbetsbeteende. En kombinerad studiedesign valdes. Den experimentella studien kompletterades med enkät och intervju. Tolv testpersoner deltog i undersökningen, fördelade lika på tre grupper: en kontrollgrupp och två experimentgrupper. Via tekniska mätningar samlades kinematisk data gällande: handledens vinkelhastighet och tummens tryckkraft; överarmens vinkel för höger- och vänster arm; överarmens vinkelhastighet för höger och vänster arm samt bålens vinkel vid fram- och bakåtböjningar. Signifikanta arbetsbeteendeförändringar kunde ej konstateras, men det förekom stora skillnader i de individuella resultaten i varje grupp. Dock kunde inte något specifikt mönster i arbetsbeteendeförändringar från de olika grupperna urskiljas. Hypotesen att arbetsbeteendeförändringar kan tillskrivas påverkan från prototypen stöddes inte av data. Resultatet från intervju- och enkätundersökning kring användarnas upplevelse och användbarhet visade att prototypen skattades som användarvänlig och användbar i sin helhet. Testpersonerna önskade förändringar i prototypens konstruktion gällande prototypens material och storlek, typ av feedback samt placering av sensorer. Vissa brister i design och utförandet av användartesterna och experimentmätningen konstateras och deras inverkan på studiens validitet och reliabilitet diskuteras. Rekommendationer ges gällande framtida testning av nästa prototyp utifrån de upptäckta bristerna. / Smart clothes are a group of technical aids that consist of clothing that has integrated/built-in sensors that measure body postures and movements and display information about possible physical overload. The purpose of this study was to evaluate prototype 1 of a smart workwear system by investigating its user experience and usability, as well as the impact of the prototype on the test subjects' work behavior. A combined study design was chosen. The experimental study was supplemented with questionnaire and interview. Twelve test subjects split in three equal groups participated in the study: one control group and two experimental groups. Through technical measurements, kinematic data was collected: angular velocity of the wrist and thumb pressure; right and left arm's angle; angular velocity for the right and left arm as well as the torso angle during forward and backward bending. Changes in work behavior were found. However, large differences in the individual results within each group were observed, with no obvious pattern of changes in work behavior between groups. The collected data did not support the hypothesis that work behavior changes can be associated with the impact of the prototype.  The result of analysis of the interviews and questionnaires about user experience and usability showed that the prototype was considered user-friendly and useful in general. Test subjects requested changes in the prototype’s construction regarding the prototype’s material and size, type of feedback and location of sensors.  Some shortcomings are observed in the test design, data collection and also in how the tests were conducted. Their impact on the validity and reliability of the study is discussed; accordingly, recommendations addressing the detected shortcomings are given regarding the future testing of the next prototype.

<p>The last two decades have shown a boom in the field of wearable sensing technology. Particularly in the consumer industry, growing trends towards personalized health have pushed new devices to report many vital signs, with a demand for high accuracy and reliability. The most common technique used to gather these vitals is photoplethysmography or PPG. PPG devices are ideal for wearable applications as they are simple, power-efficient, and can be implemented on almost any area of the body. Traditionally PPGs were utilized for capturing just heart rate, however, recent advancements in hardware and digital processing have led to other metrics including respiratory rate (RR) and peripheral oxygen saturation (SpO2), to be reported as well. Our research investigates the potential for wearable devices to be used for outpatient apnea monitoring, and particularly the ability to detect opioid misuse resulting in respiratory depression. Ultimately, the long-term goal of this work is to develop a wearable device that can be used in the rehabilitation process to ensure both accountability and safety of the wearer. This document details contributions towards this goal through the design, development, and evaluation of a device called “Kick Ring”. Primarily, we investigate the ability of Kick Ring to record heartrate (HR), RR, and SpO2. Moreover, we show that the device can calculate RR in real time and can provide an immediate indication of abnormal events such as respiratory depression. Finally, we explore a novel method for reporting apnea events through the use of several PPG characteristics. Kick Ring reliably gathers respiratory metrics and offers a combination of features that does not exist in the current wearables space. These advancements will help to move the field forward, and eventually aid in early detection of life-threatening events.</p>

Traditional fabrication methods used to manufacture biosensors for physiological, therapeutics, or health monitoring purposes are complex and rely on costly materials, which has hindered their adoption as single-use medical devices. The development of a new kind of wearable and implantable electronics relying on inexpensive materials for their manufacturing will pave the way towards the ubiquitous adoption of sticker-like health tracking devices.<div>One of growing and most promising applications for biosensors is the continuous health monitoring using mechanically soft, stretchable sensors. While these healthcare devices showed an excellent compatibility with human tissues, they still need highly trained personnel to perform multi-step, prolonged fabrication for several functioning layers of the device. In this dissertation, I propose low-cost, scalable, simple, and rapid manufacturing techniques to fabricate multifunctional epidermal and implantable sensors to monitor a range of biosignals including heart, muscle, or eye activity to characterizing of biofuids such as sweat. I have also used these devices as an implant to provide heat therapy for muscle regeneration and optical stimulation of neurons using optogenetics. These devices have also combined with those of triboelectric<br>nanogenerators to realize self-powered sensors for monitoring imperceptible mechanical biosignals such as respiratory and pulse rate.</div><div>Food health and safety has also emerged as another important frontier to develop biosensors and improve the human health and quality of life. The recent progresses on detecting microbial activity inside foods or their packages rely on development of highly functional materials. The existing materials for fabrication of food sensors, however,<br>are often costly and toxic for human health or the environment. In this dissertation, I proposed biocompatible food sensors using protein/PCL microfibers to reinforce the protein microfibrous structure in humid conditions and exploit their excellent hygroscopic properties to sense biogenic gas, as an indicator for early detection of food spoilage. Finally, my battery-free food sensors are capable of monitoring food safety with no need of extra measurement devices. Collectively, this dissertation proposes cost-effective solutions to solve human health issues, enabled by developing low-cost, functional materials and exploiting simple fabrication techniques.<br></div>