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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Biodegradation Characteristics of Nitrogen-Containing Compounds Used for Semiconductor and Optoelectrical Industries

Lun, Shin-Mei 22 June 2003 (has links)
Abstract Semiconductor and optoelectrical industries are among the major high-technological enterprises in Taiwan. Many nitrogen-containing compounds such as monoethanol amine (MEA), 1-methyl-2-pyrrolidinone (NMP), 1-amino-2-propyl alcohol (APA) and hexamethylene disilazane (HMDS) are used in both manufacturing processes. These compounds may release to environments from waste gas or water sources and become environmental pollutants if not properly treated. The main purpose of this research was to investigate the biodegradation characteristics of the four compounds. The research was performed by using a 5-L sequencing batch reactor operated at a cycling time of 24 hrs that included a filling time of 0.5 hr, an aeration and reaction time of 21 hrs, a setting time of 2 hrs, and a drawing time of 0.5 hr. The reaction conditions were as follows for the activated sludge in the reactor: MLSS (mixed liquor suspended solids) = 2000-3000 mg/L, pH = 6.8-7.2, aeration intensity = 0.46 L air/(L liquor. min), F/M (food-to-microorganism ratio) = 0.2-0.5 kg COD/(kg MLSS. Day), and C0 (initial concentration of the target compound in the mixed liquor) = 100-800 mg/L. Results demonstrate that above around 80% of all the four compounds were degraded within the aeration time of 21 hrs, and the organic nitrogen was converted to NH3-N, NO2¡Ð-N, NO3¡Ð-N, N2,and biomass-N. For MEA, above 10 % of the NH3-N hydrolyzed from the compound was nitrified for loadings of less than 0.05 kg MEA-N/m3.day, and no nitrification was observed for loadings of above 0.20 kg MEA-N/m3.day. Approximate 3% of MEA-N was converted to biomass-N and the average nitrogen content in the sludge was 4.25%. With regards to NMP, around 5, 73-83, and 14-24% of the nitrogen was converted to NH3-N+NO2¡Ð-N+NO3¡Ð-N, N2, and biomass-N, respectively, and the average nitrogen content in the sludge was 5.6%. As for the biodegradation of APA, there occurred a filamentous sludge-bulking phenomenon when C0 = 400 or 800 mg/L. With C0 increased from 200 to 800 mg/L, there was an increasing rate of ammonia formation and decreasing rate of nitrification. For the compound, around 9, 74, and 13% of the nitrogen was converted to NO2¡Ð-N, N2, and biomass-N, respectively, at a loading of 0.0358 kg APA-N/m3.day. The conversions became 12, 66, and26%, respectively, for NO2¡Ð-N, N2, and biomass-N with the loading increased to 0.0716 kg APA-N/m3.day. The average nitrogen content in the sludge was 4.9%. HMDS was biologically degraded in the emulsion state with the help of surfactants Tween 80 and Span 80. With C0 increased from 200 to 800 mg/L, there was an increasing nitrification rate and nearly constant ammonia nitrite formation rates. Above 90% of HMDS-N was converted to N2 and a few of it to biomass-N. The average nitrogen content in the sludge was around 4.5%.
2

A wavelet-based framework for efficient processing of digital imagery with an application to helmet-mounted vision systems

Hoke, Jaclyn Ann 01 August 2017 (has links)
Image acquisition devices, as well as image processing theory, algorithms, and hardware have advanced to the point that low Size-Weight-and-Power, real-time embedded imaging systems have become a reality. To be practical in a fielded application, an image processing sub-system must be able to conduct multiple, often highly complex tasks, in real-time. The design and construction of such systems have to address technical challenges, including real-time, low-latency processing and fixed-point algorithms in order to leverage lowest-power computing platforms. Further design complications stem from the reality that state-of-the-art image processing algorithms take very different forms, greatly complicating low-latency implementations. This dissertation presents the design and preliminary implementation of an image processing sub-system that minimizes computational complexity and power consumption by eliminating repeated transformations between processing domains. Specifically, this processing chain utilizes the LeGall 5/3 wavelet as the basis for applying multiple algorithms within a single domain. The wavelet processing chain is compared, in terms of image quality, computational cost, and power consumption, to a benchmark processing chain comprised of algorithms intended to produce high quality image results. Image quality is assessed through a subject matter expert evaluation. Computational cost is analyzed theoretically and empirically, and the power consumption is derived from the execution times and characteristics of the processing devices. The results demonstrate significant promise, but several areas for additional work have been identified.
3

Equipamento versátil para teste de mini-estruturas utilizadas como mini-lab. / Versatile equipment for test in the mini-structure used as a mini-lab.

Leite, Alisson Rodolfo 25 May 2016 (has links)
Este trabalho teve como objetivo geral a produção de um equipamento pequeno, multifuncional, de baixo custo e útil para as áreas de engenharia química e de química. Quanto à área de engenharia química, manipulam-se amostras em dispositivos miniaturizados que possuem operações unitárias comuns, como por exemplo, misturadores, formação de spray e remoção de partículas. Em química, efetua-se o pré-tratamento de amostras gasosas e possível detecção de compostos orgânicos voláteis (VOCs). A metodologia utilizada seguiu os protocolos para produção de equipamento. O equipamento projetado e construído apresenta três partes distintas e com as seguintes características. As amostras, que podem ser liquidas ou gasosas, são admitidas ou em fluxo contínuo ou de modo estacionário. A manipulação de dispositivos miniaturizados, como por exemplo, mini-misturadores, ocorre em três eixos distintos, o que permite o uso de dispositivos tridimensionais. Para todas as amostras a detecção é baseada em micro-balança de quartzo, com 5 cristais piezelétricos de quartzo (PQC) medindo simultaneamente e independentemente a aquisição de dados online. Quanto a amostras gasosas, é possível a detecção de VOCs na faixa de ppm e em dispositivo miniaturizado (mini manifold) para distribuição do fluxo uniformemente nos 5 PQCs. Através do uso do spray é possível a detecção de gases, líquidos e particulados. O componente sensor nos PQCs é filme fino depositado por plasma e a base de HMDS, hexametildissilazana. Esses filmes foram modificados por exposição à radiação ultravioleta (UVC) e feixe de íons (Ar+ ou He2+), os filmes após exposição mostraram-se mais eficientes na discriminação de VOCs. O equipamento foi construído com modos convencionais de produção, como por exemplo, usinagem com máquinas operatrizes como torno mecânico e fresadoras, e com partes e peças de fácil aquisição no mercado nacional. / This work aimed the production of a small equipment, multi-functional, lowcost and useful for chemical engineering and chemistry areas. Regarding the chemical engineering area samples are handled in miniaturized devices having common unit operations such as mixing, spray forming and removing particles. In chemistry, the pretreatment of gaseous samples and detection of volatile organic compounds (VOCs) could be made. The methodology followed the protocols for production equipment. The equipment designed and built features three distinct parts with the following characteristics. Samples can be liquid or gaseous, they can be admitted or continuous flow or stationary mode. The manipulation of miniaturized devices, such as minimixers occurs in three distinct axes, which allows the use of three-dimensional devices. For all samples the detection is based on quartz microbalance with 5 piezoelectric quartz crystals (PQC) the online data are acquired by measuring simultaneously and independently. As for gaseous samples, it is possible the VOCs detection in the ppm range and miniaturized device (mini manifold) to flow evenly distribution in 5 PQCs. Through the use of spray it is possible to detect gases, liquids and particulates. The sensing component in PQCs is thin film deposited by plasma and the base of HMDS hexamethyldisilazane. These films were modified by exposure to ultraviolet radiation (UVC) and ion beam (Ar+ or He2+) films after exposure were more efficient in the discrimination of VOCs. The equipment was built with conventional production methods, such as, machining with machine tools such as lathes and milling machines,, and parts and pieces of easy acquisition in the domestic market.
4

Equipamento versátil para teste de mini-estruturas utilizadas como mini-lab. / Versatile equipment for test in the mini-structure used as a mini-lab.

Alisson Rodolfo Leite 25 May 2016 (has links)
Este trabalho teve como objetivo geral a produção de um equipamento pequeno, multifuncional, de baixo custo e útil para as áreas de engenharia química e de química. Quanto à área de engenharia química, manipulam-se amostras em dispositivos miniaturizados que possuem operações unitárias comuns, como por exemplo, misturadores, formação de spray e remoção de partículas. Em química, efetua-se o pré-tratamento de amostras gasosas e possível detecção de compostos orgânicos voláteis (VOCs). A metodologia utilizada seguiu os protocolos para produção de equipamento. O equipamento projetado e construído apresenta três partes distintas e com as seguintes características. As amostras, que podem ser liquidas ou gasosas, são admitidas ou em fluxo contínuo ou de modo estacionário. A manipulação de dispositivos miniaturizados, como por exemplo, mini-misturadores, ocorre em três eixos distintos, o que permite o uso de dispositivos tridimensionais. Para todas as amostras a detecção é baseada em micro-balança de quartzo, com 5 cristais piezelétricos de quartzo (PQC) medindo simultaneamente e independentemente a aquisição de dados online. Quanto a amostras gasosas, é possível a detecção de VOCs na faixa de ppm e em dispositivo miniaturizado (mini manifold) para distribuição do fluxo uniformemente nos 5 PQCs. Através do uso do spray é possível a detecção de gases, líquidos e particulados. O componente sensor nos PQCs é filme fino depositado por plasma e a base de HMDS, hexametildissilazana. Esses filmes foram modificados por exposição à radiação ultravioleta (UVC) e feixe de íons (Ar+ ou He2+), os filmes após exposição mostraram-se mais eficientes na discriminação de VOCs. O equipamento foi construído com modos convencionais de produção, como por exemplo, usinagem com máquinas operatrizes como torno mecânico e fresadoras, e com partes e peças de fácil aquisição no mercado nacional. / This work aimed the production of a small equipment, multi-functional, lowcost and useful for chemical engineering and chemistry areas. Regarding the chemical engineering area samples are handled in miniaturized devices having common unit operations such as mixing, spray forming and removing particles. In chemistry, the pretreatment of gaseous samples and detection of volatile organic compounds (VOCs) could be made. The methodology followed the protocols for production equipment. The equipment designed and built features three distinct parts with the following characteristics. Samples can be liquid or gaseous, they can be admitted or continuous flow or stationary mode. The manipulation of miniaturized devices, such as minimixers occurs in three distinct axes, which allows the use of three-dimensional devices. For all samples the detection is based on quartz microbalance with 5 piezoelectric quartz crystals (PQC) the online data are acquired by measuring simultaneously and independently. As for gaseous samples, it is possible the VOCs detection in the ppm range and miniaturized device (mini manifold) to flow evenly distribution in 5 PQCs. Through the use of spray it is possible to detect gases, liquids and particulates. The sensing component in PQCs is thin film deposited by plasma and the base of HMDS hexamethyldisilazane. These films were modified by exposure to ultraviolet radiation (UVC) and ion beam (Ar+ or He2+) films after exposure were more efficient in the discrimination of VOCs. The equipment was built with conventional production methods, such as, machining with machine tools such as lathes and milling machines,, and parts and pieces of easy acquisition in the domestic market.
5

The use of head mounted displays (HMDs) in high angle climbing : implications for the application of wearable computers to emergency response work.

Woodham, Alexander, Timothy January 2015 (has links)
As wearable computers become more ubiquitous in society and work environments, there are concerns that their use could be negatively impactful in some settings. Previous research indicates that mobile phone and wearable computer use can impair walking and driving performance, but as these technologies are adopted into hazardous work environments it is less clear what the impact will be. The current research investigated the effects that head mounted display use has on high angle climbing, a task representative of the extreme physical demands of some hazardous occupations (such as firefighting or search and rescue work). We explored the effect that introducing a secondary word reading and later recall task has on both climbing performance (holds per meter climbed and distance covered), and word reading and recall (dual-task effects). We found a decrease in both climbing performance and word recall under dual task conditions. Further, we examined participant climbing motion around word presentation and non-word presentation times during the climbing traverse. We found that participants slowed around word presentations, relative to periods without word presentation. Finally, we compared our results to those found in previous research using similar dual-tasking paradigms. These comparisons indicated that physical tasks may be more detrimental to word recall than seated tasks, and that visual stimuli might hinder climbing performance more than audible stimuli. This research has important theoretical implications for the dual-tasking paradigm, as well at important practical implications for emergency response operations and other hazardous working environments.
6

[en] SYNTHESIS AND STRUCTURAL, MECHANICAL AND TRIBOLOGICAL CHARACTERIZATION OF THIN FILMS DEPOSITED BY PECVD FROM ORGANOSILICON / [pt] SÍNTESE E CARACTERIZAÇÃO ESTRUTURAL, MECÂNICA E TRIBOLÓGICA DE FILMES FINOS DEPOSITADOS POR PECVD A PARTIR DE ORGANOSILÍCIOS

NEILETH JOHANNA STAND FIGUEROA 29 April 2020 (has links)
[pt] Neste trabalho estudamos filmes depositados por três organosilícios em forma líquida pelo método de deposição química na fase vapor assistido por plasma (PECVD) sobre chapas de aço inoxidável 316L e lâminas de silício cristalino <100>. Os líquidos empregados foram o Hexametidissilazano (HMDSN), Hexametidissiloxano (HMDSO) e Hexametildissilano (HMDS). Determinamos as propriedades estruturais, mecânicas e tribológicas dos filmes crescidos, e a viabilidade do seu uso como revestimento protetor. Foram depositados dois conjuntos de amostras para cada líquido, o primeiro a 200C e o segundo 300oC. Em cada um dos conjuntos, a tensão de autopolarização no crescimento foi variada indo de -150V até -450V. Tentou-se caracterizar filmes crescidos a temperatura ambiente, porém não obtivemos êxito, pois delaminavam. Os filmes foram caracterizados por técnicas de perfilometria, onde determinamos que os filmes crescidos com temperaturas de 200C tiveram a maior taxa de deposição. Estes filmes para todos os líquidos possuem uma tensão interna entre 1 e 2 GPa. Os filmes foram analisados também por espectroscopia de fotoelétrons induzidos por raios-x (XPS), espectroscopia de absorção no infravermelho e espectroscopia de emissão ótica (GDOES) onde identificamos as concentrações atômicas e as ligações químicas presentes nos filmes. Com a espectroscopia Raman observamos que os filmes têm presença de carbonos com hibridização sp2. Os filmes sintetizados têm um forte caráter polimérico, e para os crescidos com tensões de autopolarização maiores que -250V, observamos a presença das bandas D e G características de filmes de carbono amorfo. As análises feitas por nanoindentação determinou que os filmes tinham dureza entre 18 e 21 GPa. A microscopia de força atômica evidenciou que os filmes têm uma rugosidade rms em torno de 0,3nm. Medida de tribologia mostraram que os filmes têm um coeficiente de atrito de 0,25. Após as medidas de tribologia, foram feitas imagens de perfilometria para determinar o desgaste. Os filmes se mostraram resistentes, com a menor taxa de 7nm/min quando submetido a uma força de 0,3 Newtons e como contra corpo uma esfera de aço inoxidável (AISI302), e após as medidas os filmes não delaminaram. Com relação ao envelhecimento do filme, alguns foram sintetizados a mais de 4 anos, e continuam bem aderidos tanto sobre o substrato de aço, como o de silício. Verificamos também a viabilidade do uso do hexametildissílazano (HMDSN) como camada adesiva para a deposição de filmes de carbono amorfo hidrogenado sobre chapas de aço inoxidável com sucesso. Fizemos também a deposição de um filme depositado a partir do hexametildissiloxano (HMDSO) sobre um parafuso de aço inoxidável para verificar a viabilidade para deposições sobre materiais com geometrias diferentes, com sucesso, o filme bem aderido em sua superfície. / [en] In this work, we study films deposited by three organosilanes in liquid phase by the plasma deposition method (PECVD) on 316L stainless steel plates and crystalline silicon slides <100>. The liquids employed were Hexamethyldisilazane (HMDSN), Hexamethyldisiloxane (HMDSO) and Hexamethyldisilane (HMDS). We determined the structural, mechanical and tribological properties of grown films, and the feasibility of their use as a protective coating. Two sets of samples were deposited for each liquid, the first at 200C and the second at 300C. In each set, the bias at the growth was varied ranging from -150V to -450V. Attempts were made to characterize films grown at room temperature, but we did not succeed because they delaminated. The films were characterized by profilometry techniques, where we determined that the films grown with temperatures of 200oC had the highest deposition rate. The films were also analyzed by x-ray photoelectron spectroscopy (XPS), infrared absorption spectroscopy (FTIR) and glow discharge optical emission spectroscopy (GDOES), where we identified the atomic concentrations and the chemical bonds present in the films. With the Raman spectroscopy we observed that the films have presence of carbons with hybridization sp2. The films synthesized have a strong polymeric character, and for those grown with bias higher than -250V, we observed the presence of D- and G- bands that are characteristics of amorphous carbon films. Analysis by nanoindentation determined that the films had a hardness between 18 and 21 GPa. Atomic force microscopy showed that the films have a roughness RMS around 0.3nm. Measurement of tribology showed that the films have a coefficient of friction of 0.25. After the tribology measurements, profilometry images were made to determine the wear. The films were resistant, with the lowest rate of 7 nm/min when subjected to a force of 0.3 Newtons and as against a body of stainless steel (AISI302), and after the measurements the films did not delaminate. Regarding the aging of the film, some were synthesized for more than 4 years, and remain well adhered both on the steel substrate and silicon. We also verified the feasibility of using hexamethyldisilazane (HMDSN) as an adhesive layer for the deposition of hydrogenated amorphous carbon films on stainless steel substrate successfully. We also deposited a film from the hexamethyldisiloxane (HMDSO) on a stainless steel screw to verify the feasibility for deposition on materials with different geometries, successfully, the film was well adhered on its surface.
7

Oxidation characteristics of fluorine-, nitrogen-, and sulfur-containing organic compounds by UV/O3

Chang, Ken-Lin 10 September 2007 (has links)
DMSO (dimethyl sulfoxide) is a liquid with a high boiling point (189 oC) that has been extensively utilized in various industries owing to its ability to dissolve various organic and inorganic compounds. DMSO is increasingly being adopted as a detergent or a photo-resistant stripping solvent in manufacturing semiconductors and liquid crystal displays (LCD). Therefore, DMSO is now a major component of wastewater. The biological treatment of DMSO-containing wastewater generates noxious DMS (dimethyl sulfide) and other compounds that may cause odor problems. Also having a high water solubility and a moderate boiling point (110 oC), tetrafluoro propanol (TFP) has been extensively applied in the manufacture of CD-R and DVD-R, due to its ability to dissolve organic dyes. The spin coating process produces a large amount of wastewater containing TFP. No reports have been written on the biodegradability of TFP to the authors¡¦ knowledge. Additionally, HMDS (hexamethyldisilazane) has been extensively used in life science microscopy and material science. For instance, the semiconductor industry employs HMDS to promote the adhesion of photo-resistant material to oxide(s). HMDS is classified as a carcinogen, and has an ammonia odor. Condensing incinerators have been found to be unsuitable for treating HMDS-containing waste gases, because of the formation of silicon dioxide, which blocks porous adsorbents. Biological treatment also appears to be unpromising due to its low water solubility and limited biodegradability. This investigation evaluates the feasibility, effectiveness and oxidation characteristics of aqueous DMSO, TFP and gaseous HMDS (hexamethyldisilazane) by UV/O3 processes. A reactor made entirely of acrylic plastic with an effective volume of 10 L was employed for the reactions. The tested VOCs concentrations were adjusted to 400¡V890mg/L and 772¡V887 mg/L for DMSO and TFP, respectively, and the gas (ozone-enriched air) flow rate was controlled at 3L/min. The effects of various solution pH values (acidic, alkaline, uncontrolled), solution temperatures (26 oC, 37 oC, 48 oC and 60 oC), and UV wavelengths (254 nm and 185+254 nm) on the removal of tested VOCs were studied . Additionally, the operation costs of treating DMSO and TFP by UV/O3 were estimated. Experimental results demonstrate that acidic conditions (pH = 3.6) favored the degradation of DMSO, and that the removal efficiency could reach 95% at a volumetric UV intensity P/V of 2.25 W/L and a reaction time of 120 min. However, alkaline conditions (pH = 9.5) favored the decomposition of TFP, with the removal efficiency reaching 95% at P/V = 2.5 W/L and a reaction time of 60 min. Both DMSO and TFP exhibited zero-order degradation kinetics when sufficient ozone was supplied. Raising the oxidation temperature did not increase the UV/O3 oxidation of TFP in the tested concentration and temperature ranges. Operation costs of the UV/O3 per unit volume of wastewater with DMSO or TFP are comparable to those of the methods described in the literature. For the gaseous HMDS oxidation, two batch reactors with effective volumes of 1.2 and 5.8 L were used employed with the decomposition occurred under UV (185+254 nm) irradiation and UV (254 nm)/O3 processes. Tests were performed with initial HMDS concentrations of 32¡V41mg/m3 under various initial ozone dosages (O3 (mg)/HMDS (mg) =1¡V5), atmospheres (N2, O2, and air), temperatures (28 oC, 46 oC, 65 oC and 80 oC), relative humilities (20%, 50%, 65% and 99%) and volumetric UV power inputs (0.87 W/L, 1.74 W/L, 4.07 W/L and 8.16 W/L) to assess their effects on the HMDS degradation rate. Results of this study demonstrate that the decomposition rates for the UV (185+254 nm) irradiation exceeded those for the UV (254 nm)/O3 process for all conditions. UV (185+254 nm) decompositions of HMDS displayed apparent first-order kinetics. A process with irradiation of UV (185+254 nm) to HMDS in air saturated with water at temperatures of 46¡V80 oC favors the HMDS degradation. With the above conditions and a P/V of around 8 W/L, k≈ 0.20 s−1, and over 90% of the initial HMDS was degraded in a time of 12s. The main mechanisms for the HMDS in wet air streams irradiated with UV (185+254 nm) were found to be caused by OH free radical oxidation produced from photolysis of water or O (1D) produced from photolysis of oxygen. Economic evaluation factors of UV (185+254 nm) and UV (254 nm)/O3 processes at various UV power inputs were also estimated.
8

Interfacial and Electrode Modifications in P3HT:PC61BM based Organic Solar Cells: Devices, Processing and Characterization

January 2015 (has links)
abstract: The inexorable upsurge in world’s energy demand has steered the search for newer renewable energy sources and photovoltaics seemed to be one of the best alternatives for energy production. Among the various photovoltaic technologies that emerged, organic/polymer photovoltaics based on solution processed bulk-heterojunctions (BHJ) of semiconducting polymers has gained serious attention owing to the use of inexpensive light-weight materials, exhibiting high mechanical flexibility and compatibility with low temperature roll-to-roll manufacturing techniques on flexible substrates. The most widely studied material to date is the blend of regioregular P3HT and PC61BM used as donor and acceptor materials. The object of this study was to investigate and improve the performance/stability of the organic solar cells by use of inexpensive materials. In an attempt to enhance the efficiency of organic solar cells, we have demonstrated the use of hexamethyldisilazane (HMDS) modified indium tin oxide (ITO) electrode in bulk heterojunction solar cell structure The device studies showed a significant enhancement in the short-circuit current as well as in the shunt resistance on use of the hexamethyldisilazane (HMDS) layer. In another approach a p-type CuI hole-transport layer was utilized that could possibly replace the acidic PEDOT:PSS layer in the fabrication of high-efficiency solar cells. The device optimization was done by varying the concentration of CuI in the precursor solution which played an important role in the efficiency of the solar cell devices. Recently a substantial amount of research has been focused on identifying suitable interfacial layers in organic solar cells which has efficient charge transport properties. It was illustrated that a thin layer of silver oxide interfacial layer showed a 28% increase in power conversion efficiency in comparison to that of the control cell. The optoelectronic properties and morphological features of indium-free ZnO/Ag/MoOx electrodes was also studied. Organic solar cells on these composite electrodes revealed good optical and electrical properties, making them a promising alternative indium free and PEDOT:PSS-free organic solar cells. Lastly, inverted solar cells utilizing zinc oxide and yttrium doped zinc oxide electron transport was also created and their device properties revealed that optimum annealing conditions and yttrium doping was essential to obtain high efficiency solar cells. / Dissertation/Thesis / Doctoral Dissertation Chemistry 2015
9

VR systems for memory assessment and depth perception

Cárdenas Delgado, Sonia Elizabeth 15 January 2018 (has links)
La evolución de la tecnología de Realidad Virtual (RV) ha contribuido en todos los campos, incluyendo la psicología. Esta evolución implica mejoras tanto en hardware como en software, que permiten experiencias más inmersivas. En un entorno de RV los usuarios pueden percibir la sensación de "presencia" y sentirse "inmersos". Estas sensaciones son posibles utilizando HMDs. Hoy en día, el desarrollo de los HMDs se ha centrado en mejorar sus características técnicas para ofrecer inmersión total. En psicología, los entornos de RV son una herramienta de investigación. Hay algunas aplicaciones para evaluar la memoria espacial que utilizan métodos básicos de interacción. Sin embargo, sistemas de RV que incorporen estereoscopía y movimiento físico todavía no se han explotado en psicología. En esta tesis, se ha desarrollado un nuevo sistema de RV que combina características inmersivas, interactivas y de movimiento. El sistema de RV (tarea en un laberinto virtual) se ha utilizado para evaluar la memoria espacial y la percepción de profundidad. Se han integrado dos tipos diferentes de interacción: una basada en locomoción que consistió en pedalear en una bicicleta fija (condición1) y otra estacionaria usando un gamepad (condición2). El sistema integró dos tipos de visualización: 1) Oculus Rift (OR); 2) Una gran pantalla estéreo. Se diseñaron dos estudios. El primer estudio (N=89) evaluó la memoria espacial a corto plazo usando el OR y los dos tipos de interacción. Los resultados indican que existían diferencias significativas entre ambas condiciones. Los participantes que utilizaron la condición2 obtuvieron mejor rendimiento que los que utilizaron la tarea en la condición1. Sin embargo, no se encontraron diferencias significativas en las puntuaciones de satisfacción e interacción entre ambas condiciones. El desempeño en la tarea correlacionó con el desempeño en las pruebas neuropsicológicas clásicas, revelando la verosimilitud entre ellas. El segundo estudio (N=59) incluyó participantes con y sin estereopsis. Este estudio evaluó la percepción de profundidad comparando los dos sistemas de visualización. Los participantes realizaron la tarea usando la condición2. Los resultados mostraron que las diferentes características del sistema de visualización no influyeron en el rendimiento en la tarea entre los participantes con y sin estereopsis. Se encontraron diferencias significativas a favor del HMD entre las dos condiciones y entre los dos grupos de participantes respecto a la percepción de profundidad. Los participantes que no tenían estereopsis y no podían percibir la profundidad cuando utilizaban otros sistemas de visualización, tuvieron la ilusión de percepción de profundidad cuando utilizaron el OR. El estudio sugiere que para las personas que no tienen estereopsis, el seguimiento de la cabeza influye en gran medida en la experiencia 3D. Los resultados estadísticos de ambos estudios han demostrado que el sistema de RV desarrollado es una herramienta apropiada para evaluar la memoria espacial a corto plazo y la percepción de profundidad. Por lo tanto, los sistemas de RV que combinan inmersión total, interacción y movimiento pueden ser una herramienta útil para la evaluación de procesos cognitivos humanos como la memoria. De estos estudios se han extraído las siguientes conclusiones generales: 1) La tecnología de RV y la inmersión proporcionada por los actuales HMDs son herramientas adecuadas para aplicaciones psicológicas, en particular, la evaluación de la memoria espacial a corto plazo; 2) Un sistema de RV como el presentado podría ser utilizado como herramienta para evaluar o entrenar adultos en habilidades relacionadas con la memoria espacial a corto plazo; 3) Los dos tipos de interacción utilizados para la navegación en el laberinto virtual podrían ser útiles para su uso con diferentes colectivos; 4) El OR permite que los usuarios sin estereopsis puedan percibir l / The evolution of Virtual Reality (VR) technology has contributed in all fields, including psychology. This evolution involves improvements in hardware and software allowing more immersive experiences. In a VR environment users can perceive the sensation of "presence" and feel "immersed". These sensations are possible using VR devices as HMDs. Nowadays, the development of the HMDs has focused on improving their technical features to offer full immersion. In psychology, VR environments are research tools because they allow the use of new paradigms that are not possible to employ in a real environment. There are some applications for assessing spatial memory that use basic methods of HCI. However, VR systems that incorporate stereoscopy and physical movement have not yet been exploited in psychology. In this thesis, a novel VR system combining immersive, interactive and motion features was developed. This system was used for the assessment of the spatial memory and the evaluation of depth perception. For this system, a virtual maze task was designed and implemented. In this system, two different types of interaction were integrated: a locomotion-based interaction pedaling a fixed bicycle (condition1), and a stationary interaction using a gamepad (condition2). This system integrated two types of display systems: 1) The Oculus Rift; 2) A large stereo screen. Two studies were designed to determine the efficacy of the VR system using physical movement and immersion. The first study (N=89) assessed the spatial short term memory using the Oculus Rift and the two types of interaction The results showed that there were statistically significant differences between both conditions. The participants who performed the condition2 got better performance than participants who performed the condition1. However, there were no statistically significant differences in satisfaction and interaction scores between both conditions. The performance on the task correlated with the performance on other classical neuropsychological tests, revealing a verisimilitude between them. The second study (N=59) involved participants who had and who had not stereopsis. This study assessed the depth perception by comparing the two display systems. The participants performed the task using the condition2. The results showed that the different features of the display system did not influence the performance on the task between the participants with and without stereopsis. Statistically significant differences were found in favor of the HMD between the two conditions and between the two groups of participants regard to depth perception. The participants who did not have stereopsis and could not perceive the depth when they used other display systems (e.g. CAVE); however, they had the illusion of depth perception when they used the Oculus Rift. The study suggests that for the people who did not have stereopsis, the head tracking largely influences the 3D experience. The statistical results of both studies have proven that the VR system developed for this research is an appropriate tool to assess the spatial short-term memory and the depth perception. Therefore, the VR systems that combine full immersion, interaction and movement can be a helpful tool for the assessment of human cognitive processes as the memory. General conclusions from these studies are: 1) The VR technology and immersion provided by current HMDs are appropriate tools for psychological applications, in particular, the assessment of spatial short-term memory; 2) A VR system like the one presented in this thesis could be used as a tool to assess or train adults in skills related to spatial short-term memory; 3) The two types of interaction (condition1 and condition2) used for navigation within the virtual maze could be helpful to use with different collectives; 4) The Oculus Rift allows that the users without stereopsis can perceive the depth perception of 3D objects and have rich 3D experiences. / L'evolució de la tecnologia de Realitat Virtual (RV) ha contribuït en tots els camps, incloent la psicologia. Aquesta evolució implica millores en el maquinari i el programari que permeten experiències més immersives. En un entorn de RV, els usuaris poden percebre la sensació de "presència" i sentir-se "immersos". Aquestes sensacions són possibles utilitzant HMDs. Avui dia, el desenvolupament dels HMDs s'ha centrat a millorar les seves característiques tècniques per oferir immersió plena. En la psicologia, els entorns de RV són eines de recerca. Hi ha algunes aplicacions per avaluar la memòria espacial que utilitzen mètodes bàsics d'interacció. Tanmateix, sistemes de RV que incorporen estereoscòpia i moviment físic no s'han explotat en psicologia. En aquesta tesi, s'ha desenvolupat un sistema de RV novell que combina immersió, interacció i moviment. El sistema (tasca en un laberint virtual) s'ha utilitzat per a l'avaluació de la memòria espacial i la percepció de profunditat. S'han integrat dos tipus d'interacció: una interacció basada en locomoció pedalejant una bicicleta fixa (condició1), i l'altra una interacció estacionària usant un gamepad (condició2). S'han integrat dos tipus de sistemes de pantalla: 1) L'Oculus Rift; 2) Una gran pantalla estereoscòpica. Dos estudis van ser dissenyats. El primer estudi (N=89) va avaluar la memòria a curt termini i espacial utilitzant l'Oculus Rift i els dos tipus d'interacció. Els resultats indiquen que hi havia diferències significatives entre les dues condicions. Els participants que van utilitzar la condició2 van obtenir millor rendiment que els participants que van utilitzar la condició1. Tanmateix, no hi havia diferències significatives dins satisfacció i puntuacions d'interacció entre les dues condicions. El rendiment de la tasca va correlacionar amb el rendiment en les proves neuropsicològiques clàssiques, revelant versemblança entre elles. El segon estudi (N=59) va implicar participants que van tenir i que van haver-hi no estereopsis. Aquest estudi va avaluar la percepció de profunditat comparant els dos sistemes de pantalla. Els participants realitzen la tasca utilitzant la condició2. Els resultats van mostrar que les diferents característiques del sistema de pantalla no va influir en el rendiment en la tasca entre els participants qui tenien i els qui no tenien estereopsis. Diferències significatives van ser trobades a favor del HMD entre les dues condicions i entre els dos grups de participants. Els participants que no van tenir estereopsis i no podien percebre la profunditat quan van utilitzar altres sistemes de pantalla (per exemple, CAVE), van tenir la il.lusió de percepció de profunditat quan van utilitzar l'Oculus Rift. L'estudi suggereix que per les persones que no van tenir estereopsis, el seguiment del cap influeix en gran mesura en l'experiència 3D. Els resultats estadístics dels dos estudis han provat que el sistema de RV desenvolupat per aquesta recerca és una eina apropiada per avaluar la memòria espacial a curt termini i la percepció de profunditat. Per això, els sistemes de RV que combinen immersió plena, interacció i moviment poden ser una eina útil per la avaluació de processos cognitius humans com la memòria Les conclusions generals que s'han extret d'aquests estudis, són les següents: 1) La tecnologia de RV i la immersió proporcionada pels HMDs són eines apropiades per aplicacions psicològiques, en particular, la avaluació de memòria espacial a curt termini; 2) Un sistema de RV com el presentat podria ser utilitzat com a eina per avaluar o entrenar adults en habilitats relacionades amb la memòria espacial a curt termini; 3) Els dos tipus d'interacció utilitzats per navegació dins del laberint virtual podrien ser útils per al seu ús amb diferent col.lectius; 3) L'Oculus Rift permet que els usuaris que no tenen estereopsis puguen percebre la percepció de profunditat dels objectes 3D i tenir / Cárdenas Delgado, SE. (2017). VR systems for memory assessment and depth perception [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/94629 / TESIS

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