Zugl.: Hannover, Univ., Diss., 2009

Zugl.: Hannover, Univ., Diss., 2008

Closed-loop performance of an active noise reduction (ANR) headset is limited by phase lag. Speaker dynamics, control hardware, and acoustic wave propagation from the control speaker to the error microphone all contribute to this phase lag. Understanding these sources of phase lag and their relative effects on performance allows for better design of an analog or digital ANR headset. This thesis demonstrates that the three most significant sources of phase lag in a digital ANR headset are the dynamics of the control speaker's diaphragm, the anti-aliasing filter, and the smoothing filter. Additionally, it is demonstrated that the acoustic wave propagation from the control speaker to the error microphone is not a major contributor of phase lag. Based on these results, it was determined that attention should be focused on the anti-aliasing and smoothing filters when attempting to minimize phase lag and improve a digital ANR system's performance. A design procedure was developed to calculate filter responses that contributed a minimal amount of phase lag to a headset. Using this minimal phase filter design procedure, a digital ANR headset was successfully built and tested. Initial testing revealed that the anti-aliasing filter was not as vital to performance as the smoothing filter. Further testing indicated that the anti-aliasing requirements could be effectively met through the use of only a smoothing filter. Therefore, in order to minimize the phase lag of a digital ANR headset, a smoothing filter may be utilized in the absence of an anti-aliasing filter for some applications. / Master of Science

Detta är en kvalitativ intervjustudie som undersöker maskinpersonalens upplevelser av att använda headsetkommunikation i arbetet ombord. Totalt sex stycken maskinbesättningsmedlemmar intervjuades om deras upplevelser av hur headsetkommunikation har påverkat utförandet av arbetet, personlig säkerhet och tidseffektivitet. Resultaten som framkom av intervjuerna visar på att kommunikationen förbättrats med headsetkommunikation genom att talkommunikationen inte begränsas av höga bullernivåer vilket leder till minskad röstbelastning. De intervjuade vittnade om att den förbättrade kommunikationen underlättade i arbetet och ökade den personliga säkerheten genom att risken för missförstånd minskade samt att maskinbesättningens situationsmedvetenhet ökade. Förbättrad ergonomi vid svåra arbetsställningar i trånga utrymmen jämfört med handburna radioapparater upplevdes även det som en fördel med headsetkommunikation. Tidsåtgången i arbetet upplevdes minska när tillgängligheten till andra besättningsmedlemmar på kommunikationsradio ökade eftersom det minskade behovet av att förflytta sig för att kommunicera samtidigt som det kan leda till snabbare responstider. Den ökade tillgängligheten upplevdes även kunna leda till att olyckor inom maskinrummet upptäcks snabbare till följd av att ett uteblivet svar på radioanrop kan ses som ett avvikande beteende. / This is a qualitative interview study researching the experience engine room personnel have with using headset communication in their work onboard. A total of six crewmembers were interviewed about their experiences and how headset communication had affected their ability to perform their work, personal safety and time efficiency. The results showed that communication had improved with the use of headsets and that speech communication where no longer limited by high noise levels which in turn leads to less strain on the voice. The interviewed crew members testified that the improved communication facilitated their work and enhanced the personal safety by decreasing the risk for misunderstandings and increasing their situational awareness. Increased ergonomics in situations with difficult working postures and limited space in comparison with hand held radios were also observed as an advantage with headset communication. Time efficiency was perceived to improve since the availability of other crewmembers on the radio increased and decreased the need for moving to another area to communicate which at the same time lead to faster response times. Increased availability of crewmembers on the radio could also shorten the time before an accident in the engine room is detected since a failure to answer a radio call would be seen as irregular behavior.

MRI is one of the biggest and most growing imaging techniques. Even though itis one of the most harmless technologies a big portion of the patients experienceanxiety during the exam. By improving the patient experience unnecessary psychologicalstress for the patient can be prevented, the patient movement wouldthen decrease and therefore the imaging can be improved without changing thetechnique. Participant observations at four dierent MRI departments werecompleted with six interviews with radiographers and technical MRI personnelin order to get insight in the work around an MRI exam and the problemsthat patients experience. The data collection resulted in three improvementareas: the atmosphere of the waiting room, the atmosphere of the MRI roomand the headset used by the patient during the MRI exam. These improvementareas were paired up with solution suggestions which were then controlled andcommented by one MRI specialist, one MRI developer and one radiographer tovalidate the suggestions. The conclusion was that there is already much doneto improve the environment in the MRI room, even though more can be done.The waiting room, on the other hand ,has not been an object for studies orfor improvements before. Therefore more calculation about how big of a protit could be, to improving the atmosphere in the waiting room, should be doneso one knows how much resources one can be put into that improvement area.Lastly there are potential solutions for how to create a much better headset butbecause the generated solutions in this area are so technically challenging moreresearch has to be done before it can be realised. / MR är en av de största och mest växande medicinsk bildgivande teknikerna som finns. Även om tekniken är helt ofarlig är det många patienter som lider av ångest kopplad till undersökningen. Genom att förbättra patientens upplevelse kan man förbygga den ångesten, då kommer också patienten kunna ligga mera still under undersökningen och därför kommer bilderna kunna förbättras utan att ändra tekniken.Datainsamlingen bestod av deltagande observationer på fyra olika röntgenavdelningar tillsammans med sex stycken intervjuer med både röntgensköterskor och personal som jobbar med MR-tekniken. Detta för att få en inblick i jobbet runt en MR undersökning och problemtiken som patienterna upplever. Datainsamlingen resulterade i tre olika förbättringsområden: väntrummet, undersökningsrummet och headsetet som patienten använder under MR-undersökningen. Dessa förbättringsområden parades ihop med förbättringsförs-lag och validerades sedan med en MR speciallist, en utvecklare och en röntgensköterska.Slutsatsen var att det idag görs mycket för att förbättre miljön i undersökningsrummet, även om mycket mer kan göras. Väntrummet, och andra sidan, har inte varit föremål för varken studier eller förbättringar och därför behöver uträkningar göras på hur stor vinst det skulle vara med en förbättrad miljö där för att veta hur mycket resurser som kan läggas på det. Till sist kan det konstateras att det finns potentiella lösningar för hur ett bättre headset skulle kunna skapas, men eftersom de förslagen som genererats i den här studien är så tekniskt avancerade behövs mer forskning för att kunna realisera lösningarna.

Denna rapport har som syfte att samla erfarenhet kring de möjligheter och den potential som finns i den EEG-teknik och de BCI-headset från NeuroSky som använts. Detta görs genom design och utveckling av ett spel som utnyttjar tekniken. Det finns redan idag ett mindre urval av sådana spel, men dessa har samtliga varit av mycket trivial karaktär och med en bristande förmåga att övertyga och engagera. Samtidigt som EEG-teknik når ut till konsumenter, ökar också allmänintresset för mental träning. Studier och rapporter visar indikationer på att sådan träning inte bara förbättrar hjärnans effektivitet, utan också kan förebygga vissa neurologiska sjukdomar som Alzheimers och demens. Forskningsrapporter pekar också på att spel med fördel kan användas för mental träning, vilket är en motivering till relevansen i att detta examensarbete representeras i form av ett spel. Hårdvaran som använts har färdiga algoritmer för avläsning av användarens koncentrations-, meditations- och blinkstyrkenivåer. Det bristande antalet olika former av input som enheterna kan leverera i sitt standardutförande, skapar begränsningar i komplexiteten på interaktionen. Trots detta har det kunnat konstateras som ett resultat av detta arbete att en betydligt rikare interaktionsmodell än den som idag ofta påträffas i tillgängliga spel, är fullt möjlig. Cortex Wars, som det utvecklade spelet heter, tänjer på gränserna genom att vara det första spelet för två samtidiga spelare; var och en med varsitt NeuroSky headset. Resultaten av arbetet visar också på att tekniken och den hårdvara som använts inte är utan problem och brister. Stabilitetsproblem finns med hårdvaran och tekniken som sådan är också väldigt känslig för yttre påverkan av exempelvis muskelaktivitet. EEG-teknik i den form som använts i arbetet har stor potential att förändra tillvaron och tillgängligheten för en stor grupp människor i flera avseenden. Här avhandlas främst spelområdet och hur detta kan tillgängliggöras på sådant vis att personer med vissa fysiska handikapp har möjlighet att spela på lika villkor som människor utan handikapp.

The purpose of this thesis is to present the different needs that can arise before VR use,and gratifications obtained by consumption. This includes finding out what media content users consume in VR, their motivations for why they consume the selectedcontent, how the choice of VR before other medium affects situations or interaction, and they feel after a session in virtual reality. The theories proven to provide a solid basis for answering the research questions are uses and gratifications theory, and medium theory. The collected empirical data is presented and analyzed within the frameworks ofthese theories, which together with previous research on virtual reality and VRheadsets, support the theoretical framework for this thesis. To gain in depth data of consumers motivations and own experiences, five semistructured qualitative interviewswhere conducted. The interviewees where asked various questions about their social and individual differences, gratifications sought and obtained, and their perception of how VR technology affects different situations and interaction. The collected empirical data is then presented and analyzed within the frameworks of uses and gratifications approach and medium theory. Results of the empirical data showed that the mostcommon needs to be satisfied by VR use are those of exersice, entertainment, practice, social interaction, and relaxation. Those needs are gratified by applications for exersice, entertainment applications, games, simulators, and social applications. The interviewees choose VR before other medium or real life activities because VR is more engaging than working out at home and less timeconsuming than leaving the house to exersice at the gym, more engaging and immersive than pc or console gaming for simulation games, and open in the sense of being able to walk up to strangers and socialize with in the virtual world. The study also showed that not only the technology hardware charachteristics, but also the software design found within the virtual environment, affects situations and interactions in a way that is perceived different and better than software found in other medium like social applications on the phone.

Researchers have long known that general aviation (GA) aircraft exhibit some of the most intense and potentially damaging sound environments to a pilot's hearing. Yet, another potentially more ominous result of this noise-intense environment is the masking of the radio communications. Radio communications must remain intelligible, as they are imperative to the safe and efficient functioning of the airspace, especially the airspace surrounding our busiest airports, Class B and Class C. However, the high amplitude, low frequency noise dominating the GA cockpit causes an upward spreading of masking with such inference that it renders radio communications almost totally unintelligible, unless the pilot is wearing a communications headset. Even with a headset, some researchers have stated that the noise and masking effects overcome the headset performance and still threaten the pilot's hearing and overall safety while in the aircraft. In reaction to this situation, this experiment sought to investigate the effects which active noise reduction (ANR) headsets have on the permissible exposure levels (PELs), speech intelligibility, workload, and ultimately the pilot's performance inside the cockpit. Eight instrument-rated pilot participants flew through different flight tasks of varying levels and types of workload embedded in four 3.5 hour flight scenarios while wearing four different headsets. The 3.5 hours were considered long duration due the instrument conditions, severe weather conditions, difficult flight tasks, and the fatiguing effects of a high intensity noise environment. The noise intensity and spectrum in the simulator facility were specifically calibrated to mimic those of a Cessna 172. Speech intelligibility of radio communications was modified using the Speech Transmission Index (STI), while measures of flight performance and workload were collected to examine any relationships between workload, speech intelligibility, performance, and type of headset. It is believed that the low frequency attenuation advantages afforded by the ANR headset decreased the signal-to-noise ratio, thereby increasing speech intelligibility for the pilot. This increase may positively affect workload and flight performance. Estimates of subjective preference and comfort were also collected and analyzed for relevant relationships. The results of the experiment supported the above hypotheses. It was found that headsets which incorporate ANR technology do increase speech intelligibility which has a direct inverse influence on workload. For example, an increase in speech intelligibility is seen with a concomitant decrease in pilot workload across all types and levels of workload. Furthermore, flight task performance results show that the pilot's headset can facilitate safer flight performance. However, the factors that influence performance are more numerous and complex than those that affect speech intelligibility or workload. Factors such as the operational performance of the communications system in the headset, in addition to the ANR technology, were determined to be highly influential factors in pilot performance. This study has concluded that the pilot's headset has received much research and design attention as a noise attenuation device. However, it has been almost completely overlooked as a tool which could be used to facilitate the safety and performance of a general aviation flight. More research should focus on identifying and optimizing the headset components which contribute most to the results demonstrated in this experiment. The pilot's headset is a component of the aviation system which could economically improve the safety of the entire system. / Ph. D.

Virtual reality (VR) är ett begrepp som blivit allt mer välkänt de senaste åren. VR kan beskrivas som en datorgenererad virtuell omvärld som användaren omsluts av. VR-miljön upplevs genom människans sinnen såsom syn, hörsel och känsel.Syftet med examensarbetet är att undersöka hur realistisk en kommersiellt tillgänglig VR-flygsimulator upplevs av piloter och undersöka om VR-teknik kan vara ett användbart läroverktyg för t.ex. flygskolor. VR-tekniken har under de senaste åren utvecklats väldigt mycket vilket gjort att många av de implementations svårigheter som VR-tekniken inneburit till stor del lösts. Nya helintegrerade head mounted displays (HMD) med inbyggd kompatibilitet gör att integreringsproblemen nästan helt försvunnit. Eftersom VR-tekniken nu är mer tillgänglig och lätthanterlig ligger det helt rätt i tiden att undersöka hur VR-teknik kan användas inom flygbranschen.Metoden för examensarbetet inleddes med informationsinsamling om VR-teknik och traditionella flygsimulatorer. Utifrån denna information skapades sedan en undersökning som bestod av två delar. Den första delen var ett experiment med en VR-flygsimulator och den andra delen var en intervju som utfördes direkt efter experimentet. Sju stridspiloter deltog i undersökningen.Resultaten av undersökningen visar att VR-flygsimulatorer upplevs som mer realistiska jämfört med traditionella flygsimulatorer. Undersökningen tyder också på att VR-teknik kan vara ett bra läroverktyg om de problem som identifierats lösts på ett tillfredsställande sätt. / Virtual reality (VR) is a rising phenomenon that has skyrocket in popularity the past year. VR is often referred to as a computer generated virtual environment the user gets immersed in. The VR environment is experienced through different types of sensory stimuli.The purpose of this thesis is to examine how realistic a commercially available VR flight simulator is being perceived by real pilots as well as examine if VR technology could be a viable educational tool for flight schools. The motivations of this thesis are the facts that the VR-technology has advanced in a quick phase. Many of the past difficulties with implementing VR technology have been addressed with new fully integrated head mounted displays therefor capability issues are no longer a big problem. Because of the simplicity of new VR-systems it’s a good time to investigate VR uses and how it compares to traditional flight simulator techniques.The method used for the thesis started with collecting information about VR technology and traditional flight simulators. With that information a survey consisting of two parts was created. The first part was an experiment with a VR flight simulator, and the second part was an interview conducted directly after the experiment. Seven jet fighter pilots participated in the survey.Our results show that a VR flight simulator is perceived as more realistic compared to a traditional flight simulator. It is also shown that VR technology could be a good educational tool if some of the issues that were found are resolved or improved upon.

Made available in DSpace on 2014-12-17T15:48:12Z (GMT). No. of bitstreams: 1 AlessandroLSF_DISSERT.pdf: 5359322 bytes, checksum: 38000f531a3025444d952f3756cbb61a (MD5) Previous issue date: 2014-03-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Interface C?rebro-Computador (ICC) ? uma ?rea que v?m sendo estudada h? d?cadas, mas apenas nos ?ltimos anos atingiu um n?vel de maturidade suficiente para permitir o seu uso com jogos digitais. Considerando que no futuro as ICCs far?o parte de sistemas interativos, ? preciso estudar o seu uso, avaliar quais s?o seus desafios e limita??es e, tamb?m, entender de forma mais apurada como adapt?-la para uso conjugado com outras formas usuais de intera??o humano-computador. Nesta pesquisa, investigamos apenas as ICCs n?o-invasivas por entendermos que esse tipo de ICC poder? ser, de fato, utilizada por usu?rios finais nesse novo paradigma de intera??o. Um dos grandes potenciais de uso de ICCs ? no dom?nio de jogos digitais, onde podem aumentar a imers?o e a divers?o atrav?s de um controle via ondas cerebrais. Apesar disso, nos dias atuais, ainda existem grandes dificuldades no processo de design e desenvolvimento de jogos dessa natureza. Como resultados da pesquisa destacamos o extenso levantamento da ?rea, a identifica??o de desafios de intera??o relacionados a ICCs, a identifica??o dos stakeholders atrav?s do referencial te?rico-metodol?gico da Semi?tica Organizacional, a confec??o de um design-rationale para apoiar o processo de design de jogos dessa natureza e, ainda, o design e a implementa??o em C++ de um jogo de batalha naval via uma ICC h?brida baseada em movimento imaginado para uso com o headset EEG Emotic EPOC