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Dissertations / Theses on the topic 'Outdoor environments'
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1
Noronha, Joseph Ajay Neil. "Ultrawideband Channel Sounding Studies in Outdoor and Outdoor-Indoor Environments." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/10006.
Full textAbstract:
Ultrawideband (UWB) is one of the most promising communication technologies in recent times with the promise of high data rates and spectral reuse.
This work analyses the outdoor and outdoor-to-indoor propagating characteristics of the UWB pulse, which can be of the order of a few gigahertz in bandwidth. The aim of the thesis is to provide the parameters needed in order to develop a channel model for such cases. The channel model would then play an important role in determining physical layer (PHY) solutions to optimally exploit these characteristics.
The measurements carried out on the Virginia Tech campus are used to compute parameters such as path loss, penetration loss and delay statistics. These are carried out in multiple frequency bands and the results are compared across frequency bands to determine effect of different frequency levels on the parameters.
Finally the results are analyzed with respect to similar parameters obtained in other measurement campaigns in an attempt to evaluate the performance of Ultrawideband vis-à-vis narrowband systems.Master of Science
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Kwon, Ju Youn. "Human responses to outdoor thermal environments." Thesis, Loughborough University, 2009. https://dspace.lboro.ac.uk/2134/5519.
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This thesis presents a series of studies into the responses of people to outdoor thermal conditions experienced over all seasons in the United Kingdom. The aim was to investigate practical methods for predicting human responses to outside weather conditions, which would be useful in predicting effects on human comfort and health. The studies involved both laboratory experiments and field trials. One particular aspect of outside conditions, not usually investigated in laboratory studies, is the contribution of solar radiation. Single subject and thermal manikin studies were used to determine the contribution of solar radiation to human response. In addition to this, a total of 168 subjects responses were recorded during trials at the Loughborough University weather station compound. (latitude 52.47N and longitude 01.11W). The trials were distributed between July 2007 and October 2008. This provided a comprehensive data-base for the evaluation of thermal indices. The thesis is divided into four parts. Part one provides an introduction to the subject and a comprehensive literature review. It also describes equipment, calibration procedures and methods used. Part two quantified the contribution of solar radiation to the heat load on a person. A human subject and a heated thermal manikin were exposed to outdoor thermal conditions, while in light clothing and (for the person) conducting a step test. They were then exposed to identical conditions in a thermal chamber, but without the contribution of the sun. The conditions outside were 23˚C air temperature, 42˚C mean radiant temperature and 54% relative humidity with an average air velocity of 0.75 ms-1. The difference in sweat rate (person) and heat required (manikin) between outdoor and indoor conditions were used to estimate the contribution of the sun. Using three different analyses estimates were 14 Wm-2, 35 Wm-2 and 50 Wm-2 depending upon the assumptions made. Part three describes current thermal indices that can be used to assess the effects of weather conditions on people. It also presents the results of weather station measurements over the time period considered. In chapters 8 and 9 field trials are described which capture both the thermal conditions and human physiological and subjective responses to those conditions. Chapter 10 uses the data collected to provide an evaluation of current thermal indices for predicting human responses. The range of air temperature and relative humidity (at 2 pm) over a year was -2˚C to 29˚C and 34% to 95% respectively. Wind speed varied and was greater in winter and spring than in summer and autumn. Solar radiation was influenced by the altitude of the sun which depended upon season. Mean solar radiation increased from December to June and decreased from June to December. The subjective and physiological responses for 130 people (65 males and 65 females) over a range of outdoor weather conditions are presented. Physiological responses for females generally showed a stronger relationship with environmental variables and subjective responses than those for males. The subjective and physiological responses of four groups (one in each season of the year - involving a total of 38 people), are presented. It was found that there were significant individual differences in response. Part four provides a suggestion for an improved thermal index. The PMV (Predicted Mean Vote) out of four thermal indices (WBGT, PMV, WCI/tch and Twc) had the strongest relationship with environmental variables and physiological responses but had a weak relationship with subjective responses. A PMVoutdoors index was developed to improve the prediction of subjective responses for the outdoor conditions investigated. Conclusions and recommendations for future research are provided.
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Rosenquist, Calle, and Andreas Evesson. "Visual Servoing In Semi-Structured Outdoor Environments." Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-653.
Full textAbstract:
The field of autonomous vehicle navigation and localization is a highly active research
topic. The aim of this thesis is to evaluate the feasibility to use outdoor visual navigation in a semi-structured environment. The goal is to develop a visual navigation system for an autonomous golf ball collection vehicle operating on driving ranges.
The image feature extractors SIFT and PCA-SIFT was evaluated on an image database
consisting of images acquired from 19 outdoor locations over a period of several weeks to
allow different environmental conditions. The results from these tests show that SIFT-type
feature extractors are able to find and match image features with high accuracy. The results also show that this can be improved further by a combination of a lower nearest neighbour threshold and an outlier rejection method to allow more matches and a higher ratio of correct matches. Outliers were found and rejected by fitting the data to a homography model with the RANSAC robust estimator algorithm.
A simulator was developed to evaluate the suggested system with respect to pixel noise from illumination changes, weather and feature position accuracy as well as the distance to features, path shapes and the visual servoing target image (milestone) interval. The system was evaluated on a total of 3 paths, 40 test combinations and 137km driven. The results show that with the relatively simple visual servoing navigation system it is possible to use mono-vision as a sole sensor and navigate semi-structured outdoor environments such as driving ranges.
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Tanase, Cristina-Madalina. "Multi-person tracking system for complex outdoor environments." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-245082.
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The thesis represents the research in the domain of modern video tracking systems and presents the details of the implementation of such a system. Video surveillance is a high point of interest and it relies on robust systems that interconnect several critical modules: data acquisition, data processing, background modeling, foreground detection and multiple object tracking. The present work analyzes different state of the art methods that are suitable for each module. The emphasis of the thesis is on the background subtraction stage, as the final accuracy and performance of the person tracking dramatically dependent on it. The experimental results show the performance of four different foreground detection algorithms, including two variations of self-organizing feature maps for background modeling, a machine learning technique. The undertaken work provides a comprehensive view of the actual state of the research in the foreground detection field and multiple object tracking and offers solution for common problems that occur when tracking in complex scenes. The chosen data set for experiments covers extremely different and complex scenes (outdoor environments) that allow a detailed study of the appropriate approaches and emphasize the weaknesses and strengths of each algorithm. The proposed system handles problems like: dynamic backgrounds, illumination changes, camouflage, cast shadows, frequent occlusions and crowded scenes. The tracking obtains a maximum Multiple Object Tracking Accuracy of 92,5% for the standard video sequence MWT and a minimum of 32,3% for an extremely difficult sequence that challenges every method.
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Pitman, David (David J. ). "Collaborative Micro Aerial Vehicle exploration of outdoor environments." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/61318.
Full textAbstract:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 121-124).
Field personnel, such as soldiers, police SWAT teams, and first responders, face challenging, dangerous environments, often with little advance knowledge or information about their surroundings. Currently, this Intelligence, Surveillance & Reconnaissance (ISR) information is provided by satellite imagery and prior or second-hand experiences. Although satellite imagery is currently the preferred method for gaining Situational Awareness (SA) about an outdoor environment, it has many shortcomings. Unclassified satellite imagery maps available to these field personnel are flat images, with no elevation information and fixed points of view. These maps are often outdated, and, due to shadows and shading, give false impressions of elevations and details of the environment. Critical features of buildings, such as doorways and windows are hidden from view. Combined, these flaws often give field personnel a false mental model of their environment. Given the need of these personnel to simultaneously perform a primary task, such as finding a Person of Interest (POI), as well as explore the environment, an autonomous robot would allow these groups to better perform ISR and improve their SA in real-time. Recent efforts have led to the creation of Micro Aerial Vehicles (MAVs), a class of Unmanned Aerial Vehicle (UAV), which are small and have autonomous capabilities. At most a few feet in size, a MAV can hover in place, perform Vertical Take-Off and Landing, and easily rotate with a small sensor payload. The compact size of these vehicles and their maneuvering capabilities make them well-suited for performing highly localized ISR missions with MAV operator working within the same environment as the vehicle. Unfortunately, existing interfaces for MAVs ignore the needs of field operators, requiring bulky equipment and the operator's full attention. To be able to collaboratively explore an environment with a MAV, an operator needs a mobile interface which can support the need for divided attention. To address this need, a Cognitive Task Analysis (CTA) was performed with the intended users of the interface to assess their needs, as well as the roles and functions a MAV could provide. Based on this CTA, a set of functional and information requirements were created which outlined the necessities of an interface for exploring an environment with a MAV. Based on these requirements, the Micro Aerial Vehicle Exploration of an Unknown Environment (MAVVUE) interface was designed and implemented. Using MAV-VUE, operators can navigate the MAV using waypoints, which requires little attention. When the operator needs more fine-grained control over the MAV's location and orientation, in order to obtain imagery or learn more about an environment, he or she can use the Nudge Control mode. Nudge Control uses Perceived First Order (PFO) control to allow an operator effectively "fly" a MAV with no risk to the vehicle. PFO control, which was invented for MAV-VUE, utilizes a 0th order feedback control loop to fly the MAV, while presenting 1st order controls to the operator. A usability study was conducted to evaluate MAV-VUE. Participants were shown a demonstration of the interface and only given three minutes of training before they performed the primary task. During this task, participants were given search and identify objectives, MAV-VUE installed on an iPhone@ and an actual MAV to explore a GPS-simulated urban environment. Participants performed well at the task, with thirteen of fourteen successfully performing their objectives with no crashes or collisions. Several statistically significant correlations were found between participants' performance and their usage of the interface. Operators who were more patient and had higher scores on a spatial orientation pretest tended to have more precise MAV control. Future design and implementation recommendations learned from this study are discussed.
by David Pitman.
M.Eng.
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ALHAJ, ALI SOUMA MAHMOUD. "TECHNOLOGIES FOR AUTONOMOUS NAVIGATION IN UNSTRUCTURED OUTDOOR ENVIRONMENTS." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1064404165.
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Ali, Souma M. A. "Technologies for autonomous navigation in unstructurted outdoor environments." Cincinnati, Ohio : University of Cincinnati, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=ucin1064404165.
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Henderson, D. G. E., and n/a. "Botanic gardens as outdoor museums." University of Canberra. Landscape Architecture, 1996. http://erl.canberra.edu.au./public/adt-AUC20060720.153832.
Full textAbstract:
Museum techniques of presentation are reviewed for the
possibility of use in contemporary botanic gardens.
Supporting evidence suggests that these techniques are
being successfully applied in some botanic gardens around
the world. Institutions that have adopted museum techniques
have been found to operate efficiently, whilst providing
increased levels of enjoyment and education for visitors.
Cultural differences between various countries have
small influences on the most effective presentation
techniques used, but further local research is required to
uncover visitor preferences and use patterns in Australian
botanic gardens. General principles of design that work
well in the indoor environments of international musuems
apply well in the outdoor environments of botanic gardens.
Therefore greater use should be made of existing
international museum research into visitor patterns of
behaviour where it is locally appropriate.
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Asmar, Daniel. "Vision-Inertial SLAM using Natural Features in Outdoor Environments." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2843.
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Simultaneous Localization and Mapping (SLAM) is a recursive probabilistic inferencing process used for robot navigation when Global Positioning Systems (GPS) are unavailable. SLAM operates by building a map of the robot environment, while concurrently localizing the robot within this map. The ultimate goal of SLAM is to operate anywhere using the environment's natural features as landmarks. Such a goal is difficult to achieve for several reasons. Firstly, different environments contain different types of natural features, each exhibiting large variance in its shape and appearance. Secondly, objects look differently from different viewpoints and it is therefore difficult to always recognize them. Thirdly, in most outdoor environments it is not possible to predict the motion of a vehicle using wheel encoders because of errors caused by slippage. Finally, the design of a SLAM system to operate in a large-scale outdoor setting is in itself a challenge. The above issues are addressed as follows. Firstly, a camera is used to recognize the environmental context (e. g. , indoor office, outdoor park) by analyzing the holistic spectral content of images of the robot's surroundings. A type of feature (e. g. , trees for a park) is then chosen for SLAM that is likely observable in the recognized setting. A novel tree detection system is introduced, which is based on perceptually organizing the content of images into quasi-vertical structures and marking those structures that intersect ground level as tree trunks. Secondly, a new tree recognition system is proposed, which is based on extracting Scale Invariant Feature Transform (SIFT) features on each tree trunk region and matching trees in feature space. Thirdly, dead-reckoning is performed via an Inertial Navigation System (INS), bounded by non-holonomic constraints. INS are insensitive to slippage and varying ground conditions. Finally, the developed Computer Vision and Inertial systems are integrated within the framework of an Extended Kalman Filter into a working Vision-INS SLAM system, named VisSLAM.
VisSLAM is tested on data collected during a real test run in an outdoor unstructured environment. Three test scenarios are proposed, ranging from semi-automatic detection, recognition, and initialization to a fully automated SLAM system. The first two scenarios are used to verify the presented inertial and Computer Vision algorithms in the context of localization, where results indicate accurate vehicle pose estimation for the majority of its journey. The final scenario evaluates the application of the proposed systems for SLAM, where results indicate successful operation for a long portion of the vehicle journey. Although the scope of this thesis is to operate in an outdoor park setting using tree trunks as landmarks, the developed techniques lend themselves to other environments using different natural objects as landmarks.
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Bhatia, Nimmi. "Mitigation of hyperthermia in outdoor environments for the elderly." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq24443.pdf.
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Muenhor, Dudsadee. "Polybrominated diphenyl ethers (PBDEs) in indoor and outdoor environments." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/2854/.
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PBDEs were detected in all air and dust samples. The PBDE congener profile in both outdoor and indoor air samples from Thai e-waste storage facilities and homes was dominated by BDE-47 and 99, whilst the predominant BFRs in all dust samples from Thai e-waste storage facilities were BDE-209, BDE-208, BDE-207, BDE-206, BDE-197, BDE-183, BDE-99, BDE-47 and DBDPE. Furthermore, BDEs 99 and 47 were the most abundant congeners in all dust samples from Thai houses and cars and UK homes. Under realistic high-end scenarios of occupational exposure to BDE-99 via dust ingestion, workers in Thai e-waste storage facilities were exposed above a recently-published Health Based Limit Value for this congener. For non-occupational exposure, under a high-end exposure scenario, the exposure to BDE-99 of such Thai children via dust ingestion is either very close to or in exceedance of the HBLV. PBDE levels in most of the areas monitored within the same rooms were not statistically significantly different. Similarly, concentrations of PBDEs in the majority of rooms within the same houses were not statistically significantly different between rooms. Possible dilution of PBDE levels in dust with increasing dust loadings has been identified in a small number of rooms.
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Parsons, Russ John. "Recovery from stress during exposure to videotaped outdoor environments." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185720.
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There is a long history of visual preferences for natural environments over urban environments, as well as beliefs in the restorative value of time spent in natural environments. Diverse theoretical perspectives, such as information overload, learning and evolutionary theories, can be used to help explain these preferences and beliefs, and early empirical research has found tentative support for them. The present study capitalizes on a recovery-from-stress experimental paradigm developed by Ulrich. Subjects are presented with a brief videotaped stressor followed by a brief videotaped outdoor environment while psychological and physiological indicators of arousal and emotion are monitored. In this study, two stressors and four environments were manipulated between subjects. The environments differed along two dimensions that were derived from visual preference research and theoretical predictions: whether they were natural or urban in character, and the presence or absence of a river. Physiological indicators of arousal included heart rate, skin conductance, respiration rate and salivary cortisol levels. Facial electromyographic (EMG) placements were used to assess the emotional valence of subjects' responding. The Zuckerman Inventory of Personal Responses (ZIPERS) was used to assess psychological responding. Analyses yielded a limited and occasionally inconsistent pattern of results. Many of the inconsistent responses to the environments were found across stressors, suggesting that either arousal level or the particular nature of the arousal generated by the two stressors may have interacted with the recovery environments. Despite these inconsistencies, the tentative conclusions that could be reached were generally consistent with past research and theoretical predictions. Evidence from the arousal variables suggested that the Nature and Water environments elicited less arousal during the recovery phase than did the Urban and Non-Water environments; and, there was corraboration or partial corraboration for each of these findings from the self-report data. Similarly, data from the EMG placements favored the Nature environments over the Urban environments, and in particular suggested that the Non-Water Natural (meadow) environment was less likely to produce negative emotions than the other environments. Again, this finding received some support from the self-report data. Possible explanations for the limited and occasionally inconsistent nature of the findings are offered in the discussion section, with the most likely candidate being the relatively attractive Urban environments used in this study compared to those used in past research.
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Ljungzell, Erik. "Multipath-assisted Single-anchor Outdoor Positioning in Urban Environments." Thesis, Linköpings universitet, Reglerteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-149051.
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An important aspect of upcoming fifth-generation (5G) cellular communication systems is to improve the accuracy with which user equipments can be positioned. Accurately knowing the position of a user equipment is becoming increasingly important for a wide range of applications, such as automation in industry, drones, and the internet of things. Contrary to how existing techniques for outdoor cellular positioning deal with multipath propagation, in this study the aim is to use, rather than mitigate, the multipath propagation prevalent in dense urban environments. It is investigated whether it is possible to position a user equipment using only a single transmitting base station, by exploiting position-related information in multipath components inherent in the received signal. Two algorithms are developed: one classical point-estimation algorithm using a grid search to find the cost function-minimizing position, and one Bayesian filtering algorithm using a point-mass filter. Both algorithms make use of BEZT, a set of 3D propagation models developed by Ericsson Research, to predict propagation paths. A model of the signal received by a user equipment is formulated for use in the positioning algorithms. In addition to the signal model, the algorithms also require a digital map of the propagation environment. The algorithms are evaluated first on synthetic measurements, generated using BEZT, and then on real-world measurements. For both the synthetic and real-world measurement sets, the Bayesian point-mass filter outperforms the classical algorithm. It is observed how, given synthetic measurements, the algorithms yield better estimates in non-line-of-sight regions than in regions where the user equipment has line-of-sight to the transmitting base station. Unfortunately, these results do not generalize well to the real-world measurements, where, overall, neither algorithm is able to provide reliable and robust position estimates. However, as multipath-assisted positioning, to the best of our knowledge, has not been used for outdoor cellular positioning before, there are plenty of algorithm extensions, modifications, and problem aspects left to be studied - some of which are discussed in the concluding chapters.
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Guastella, Dario Calogero. "Ground Vehicle Navigation through Traversability Analysis of Outdoor Environments." Doctoral thesis, Università di Catania, 2019.
Find full textAbstract:
This thesis describes the research activity carried out on the navigation of unmanned ground vehicles in outdoor unstructured environments. These environments are very common in a wide variety of real-application scenarios, such as search and rescue for post-disaster response, monitoring of the environment and industrial facilities, precision farming, planetary exploration etc.. For this reason, robotics researchers have been investigating such kind of environments for decades. However, the problem of vehicle navigation in these scenarios is not fully solved. In fact, a general approach for ground vehicle motion planning, taking into account both the robot and the environment features, is still far to be defined. In the literature, this problem has been addressed through the so-called traversability analysis. It can be seen as an assessment of the difficulty for a specific ground vehicle, characterized by its own locomotion features, to cross a terrain area, which is in turn characterized by its own morphology and appearance.
The works reported in this thesis are related to the problem of geometry-based traversability analysis. It consists in deriving maps of traversing costs from three-dimensional models of the environment. These costmaps are extremely useful in challenging environments, as they are used in robot motion planning to avoid unsafe paths for the vehicle itself. Still in the context of 3D reconstructions, a solution for the remote drive of mobile robotic platforms has been developed. The aim has been to enhance the operator interface with helpful information, including traversing costs, via graphical elements presented in a mixed reality context. Finally, coverage path planning for unmanned aerial vehicles has been investigated as well. It is a specific kind of path planning related to three-dimensional photogrammetric reconstruction. In particular, an approach to manage a flock of aerial vehicles has been developed, in order to parallelize the coverage mission. The coverage task is the first step needed for the environment reconstruction. Eventually the traversability analysis can be performed on the obtained reconstruction.
Experimental and on-field trials have also been performed on a real mobile robotic platform, for the testing of the proposed approaches. The results achieved are reported and widely discussed.
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Kamenou, Sophie. "Promoting drama activities in outdoor environments for elementary school children." Thesis, Linköping University, Department of Arts, Craft and Design, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7011.
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This study was undertaken among teachers in different schools of Sweden and among several teachers with experience in teaching drama during February and March 2006. The aim was to explore what the beneficial aspects of working with drama outdoors are and simultaneously to examine any problems that may appear and what kind of activities the teachers believe are more conducive to outdoor settings.
Qualitative research methods were used for this study. An open questionnaire was sent to eight drama teachers for their opinion on doing drama activities in outdoor environments. Also, activities recommended for using in outdoor settings were prepared and send to several teachers, some of whom had previous experience working outdoors. They were asked later in an open questionnaire to evaluate the relative success of the activities they managed to do and the positive aspects and problems they encountered in doing the activities in outdoor settings. Additionally, some unstructured observations of two different groups took place in two elementary schools.
The research reveals that in general terms, the teachers encountered many beneficial outcomes of using drama activities in outdoor environments and they encountered some problems as well.
This study demonstrates the relative success and benefits of drama activities in outdoor environments and addresses some common problems that may appear. It contains a variety of drama activities that can be useful to teachers who are interested in working with drama in the outdoors. The discussion includes some recommendations for teachers.
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Van, der Walt Ralene. "A healing outdoor experience - the potential of outdoor environments to enhance psychological healing at Weskoppies psychiatric hospital." Diss., University of Pretoria, 2009. http://hdl.handle.net/2263/30272.
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The purpose of this thesis was to explore the potential of a designed physical outdoor environment to improve the social environment and thereby enhance the psychological healing process at Psychiatric institutions. Weskoppies Psychiatric Hospital situated in Pretoria West served as a model for testing the hypothesis. The physical and social environment at Weskoppies was analyzed through observations, interviews and literature research. Findings from analysis and theoretical research regarding the influences that physical and social outdoor environments have on mental health, were synthesized to establish design guidelines. These informed the design decision making process and assisted in the proposal of an outdoor environment with emotional healing potential. An open space framework and catalytic sketch plan was designed to illustrate the application of the design guidelines. The author found that an outdoor environment that encourage independence, purpose, consciousness, rest, connectedness and physical activities have the potential to enhance the psychological healing process. The open space framework and sketch plan proved that these guidelines can be accommodated on different scales. CopyrightDissertation (ML(Prof))--University of Pretoria, 2009.
Architecture
unrestricted
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Kloos, Gerold. "Radio-Frequency Signal Strength Based Localisation in Unstructured Outdoor Environments." Faculty of Engineering and Information Technologies, 2008. http://hdl.handle.net/2123/2242.
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Doctor of Philosophy (PhD)This thesis addresses the issues arising in range-only localisation and tracking using Radio Frequency Received Signal Strength Indicator measurements. One of the key issues in Radio Frequency (RF) based localisation and tracking applications is to obtain an accurate sensor representation. Such a sensor model is one of the prerequisites to achieve high accuracy and precision in the localisation and tracking task. The sensor models used at present for this task are very simplistic, and as a consequence are unable to achieve highly accurate and precise localisation. While such an accurate sensor description is desirable it has not been presented for RF sensors. This thesis addresses the task of obtaining an accurate sensor model for RF sensors. The major drawbacks of the most commonly used model, the nth power model, are demonstrated. A new model to satisfy the necessary requirements for high accuracy localisation is developed. This model is based on theoretical considerations and experimental data. It depicts the real occurring behaviour of RF sensors more closely than the models used so far for RF based range-only localisation. The use of this better sensor representation offers the possibility of achieving more accurate localisation. The expected performance of the alternative sensor model is compared to the commonly used nth power model. Furthermore, the inherent properties of the new sensor model are presented and their ramifications with regards to the goal of achieving highly accurate localisation are discussed. In addition to the sensor model development, the well-known probabilistic filtering techniques Kalman Filter, Particle Filter and Histogram Filter are compared and used to implement 1-dimensional and 2-dimensional range-only trackers. The filtering techniques are evaluated with respect to their suitability for appropriately handling the new multi-modal sensor model and the resulting multi-modal state distributions, and to provide correct and conclusive localisation and tracking results. Results from experiments using real data obtained in outdoor environments with a prototype RF localisation system as well as results obtained from simulations are presented in this thesis to validate the theoretical findings and the newly developed sensor model.
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Monsour, Katrina L. "Outdoor education programs as gender equitable environments? An ethnographic study." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ28447.pdf.
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Burcher, Lise M. "A process for the design of outdoor health care environments." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0004/MQ43144.pdf.
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Behley, Jens [Verfasser]. "Three-dimensional Laser-based Classification in Outdoor Environments / Jens Behley." Bonn : Universitäts- und Landesbibliothek Bonn, 2014. http://d-nb.info/1048091473/34.
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Kloos, Gerold. "Radio-Frequency Signal Strength Based Localisation in Unstructured Outdoor Environments." Thesis, The University of Sydney, 2007. http://hdl.handle.net/2123/2242.
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This thesis addresses the issues arising in range-only localisation and tracking using Radio Frequency Received Signal Strength Indicator measurements. One of the key issues in Radio Frequency (RF) based localisation and tracking applications is to obtain an accurate sensor representation. Such a sensor model is one of the prerequisites to achieve high accuracy and precision in the localisation and tracking task. The sensor models used at present for this task are very simplistic, and as a consequence are unable to achieve highly accurate and precise localisation. While such an accurate sensor description is desirable it has not been presented for RF sensors. This thesis addresses the task of obtaining an accurate sensor model for RF sensors. The major drawbacks of the most commonly used model, the nth power model, are demonstrated. A new model to satisfy the necessary requirements for high accuracy localisation is developed. This model is based on theoretical considerations and experimental data. It depicts the real occurring behaviour of RF sensors more closely than the models used so far for RF based range-only localisation. The use of this better sensor representation offers the possibility of achieving more accurate localisation. The expected performance of the alternative sensor model is compared to the commonly used nth power model. Furthermore, the inherent properties of the new sensor model are presented and their ramifications with regards to the goal of achieving highly accurate localisation are discussed. In addition to the sensor model development, the well-known probabilistic filtering techniques Kalman Filter, Particle Filter and Histogram Filter are compared and used to implement 1-dimensional and 2-dimensional range-only trackers. The filtering techniques are evaluated with respect to their suitability for appropriately handling the new multi-modal sensor model and the resulting multi-modal state distributions, and to provide correct and conclusive localisation and tracking results. Results from experiments using real data obtained in outdoor environments with a prototype RF localisation system as well as results obtained from simulations are presented in this thesis to validate the theoretical findings and the newly developed sensor model.
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Melkumyan, Narek. "Surface-based Synthesis of 3D Maps for Outdoor Unstructured Environments." Thesis, The University of Sydney, 2009. http://hdl.handle.net/2123/5125.
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This thesis is concerned with the theoretical and practical development of a surface-based mapping algorithm for reliable and robust localization and mapping in prior unknown and unstructured environments. A surface-based map consists of a set of compressed surfaces, processed and represented without geometrical modelling. Each surface in the surface-based map represents an object in the environment. The ability to represent the exact shapes of objects via individual surfaces during the mapping process makes the surface-based mapping algorithm valuable in a number of navigation applications, such as mapping of prior unknown indoor and outdoor unstructured environments, target tracking, path planning and collision avoidance. The ability to unify representations of the same object taken from different viewpoints into a single surface makes the algorithm capable of working in multi-robot mapping applications. A surface-based map of the environment is build incrementally by acquiring the 3D range image of the scene, extracting the objects' surfaces from the 3D range image, aligning the set of extracted surfaces relative to the map and unifying the aligned set of surfaces with surfaces in the map. In the surface unification process the surfaces representing the same object are unified to make a single surface. The thesis introduces the following new methods which are used in the surface-based mapping algorithm: the extraction of surfaces from 3D range images based on a scanned surface continuity check; homogenization of the representation of the non-homogenously sampled surfaces; the alignment of the surface set relative to a large set of surfaces based on surface-based alignment algorithm; evaluating the correspondence between two surfaces based on the overlap area between surfaces; unification of the two surfaces belonging to the same object; and surface unification for a large set of surfaces. The theoretical contributions of this thesis are demonstrated with a series of practical implementations in different outdoor environments.
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Melkumyan, Narek. "Surface-based Synthesis of 3D Maps for Outdoor Unstructured Environments." Australian Centre for Field Robotics, 2009. http://hdl.handle.net/2123/5125.
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Doctor of Philosophy(PhD)This thesis is concerned with the theoretical and practical development of a surface-based mapping algorithm for reliable and robust localization and mapping in prior unknown and unstructured environments. A surface-based map consists of a set of compressed surfaces, processed and represented without geometrical modelling. Each surface in the surface-based map represents an object in the environment. The ability to represent the exact shapes of objects via individual surfaces during the mapping process makes the surface-based mapping algorithm valuable in a number of navigation applications, such as mapping of prior unknown indoor and outdoor unstructured environments, target tracking, path planning and collision avoidance. The ability to unify representations of the same object taken from different viewpoints into a single surface makes the algorithm capable of working in multi-robot mapping applications. A surface-based map of the environment is build incrementally by acquiring the 3D range image of the scene, extracting the objects' surfaces from the 3D range image, aligning the set of extracted surfaces relative to the map and unifying the aligned set of surfaces with surfaces in the map. In the surface unification process the surfaces representing the same object are unified to make a single surface. The thesis introduces the following new methods which are used in the surface-based mapping algorithm: the extraction of surfaces from 3D range images based on a scanned surface continuity check; homogenization of the representation of the non-homogenously sampled surfaces; the alignment of the surface set relative to a large set of surfaces based on surface-based alignment algorithm; evaluating the correspondence between two surfaces based on the overlap area between surfaces; unification of the two surfaces belonging to the same object; and surface unification for a large set of surfaces. The theoretical contributions of this thesis are demonstrated with a series of practical implementations in different outdoor environments.
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Alamgir, Nyma. "Computer vision based smoke and fire detection for outdoor environments." Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/201654/1/Nyma_Alamgir_Thesis.pdf.
Full textAbstract:
Surveillance Video-based detection of outdoor smoke and fire has been a challenging task due to the chaotic variations of shapes, movement, colour, texture, and density. This thesis contributes to the advancement of the contemporary efforts of smoke and fire detection by proposing novel technical methods and their possible integration into a complete fire safety model. The novel contributions of this thesis include an efficient feature calculation method combining local and global texture properties, the development of deep learning-based models and a conceptual framework to incorporate weather information in the fire safety model for improved accuracy in fire prediction and detection.
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Lisurici, Fabio. "Development of a mobile robot: control and navigation for outdoor environments." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Find full textAbstract:
For mobile robots to be able to work safely among humans, they have to be accurate in their motion acquiring knowledge via sensors. Nowadays mobile robots are being used more and more in outdoor environment for many purposes. This thesis covers the essential aspects of a mobile robot combining perception, state estimation and control for outdoor navigation.
The first part involves an overview of the concepts related to kinematics, optimization and real time systems. Those topics give the basis to understand the following chapters in which more advanced topics are covered.
The second part covers the state of the art review of the algorithms used in localization and navigation.
The last part is dedicated to the decisions related to the implementation for the specific case study. It is described how GPS, IMU and wheel odometry have been fused via EKF to get an estimate of the robot pose. Moreover, the developed control law is described in details with relative performances. The last chapter covers the simulation phase in which results are shown with possible enhancements.
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Triguero, Mas Margarita 1985. "Natural outdoor environments and adults' health : associations, effect modifiers and mediators." Doctoral thesis, Universitat Pompeu Fabra, 2017. http://hdl.handle.net/10803/565926.
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This thesis aims at (a) evaluating the association between natural outdoor environments (NOE) and health in adults and potential effect modifiers of this association, and (b) investigating the possible mechanism of this association. Data was derived from two cross-sectional studies (including a nested one) and one experimental study. Exposure assessment included residential NOE exposure, and contact with NOE (objectively measured with smartphones and event-based exposures). Health outcomes included mainly subjectively mental health. The potential effect modifier of gender, age, socioeconomic status, urbanisation degree/city and exposure time was evaluated. The possible mechanisms investigated were: (NOE) physical activity, stress/restoration, social contacts, noise, and air pollution. Results of the present work suggest that NOE exposure (both residential and contact with NOE) was positively associated with adults’ chronic health, mainly for green space and greenery, and specially for surrounding greenness. Event-based exposure to NOE was also positively associated to adults’ acute health effects. No strong conclusions could be drawn about groups of population that could benefit more from NOE exposure. Physical activity might not be a mediator of the NOE-health associations. Stress reduction/restoration and air pollution might be partial mediators of these associations. The relationship between NOE exposure -NOE physical activity could be modified by various factors. We highlight the limitations of existing studies in the field and provide recommendations for future research. In the meanwhile, urban planners and policy makers should consider all the mechanisms, targeting the entire population, and use “just green enough” strategies supported by anti-gentrification policies.Els objectius d’aquesta tesi eren (a) avaluar l’associació entre entorns naturals exteriors (ENE) i la salut dels adults i el potencial efecte modificador d’aquesta associació i (b) investigar els possibles mecanismes d’aquesta associació. En la present tesi s’han utilitzat dades de dos estudis transversals (incloent un estudi niat) i un estudi experimental. L’estimació de l’exposició incloïa l’exposició residencial a ENE i el contacte amb ENE (mesurat objectivament amb smartphones i l’exposició basada-en-event). Els resultats en salut avaluats incloïen principalment la salut mental subjectiva. Els potencials modificadors d’efecte que es van explorar eren el gènere, l’edat, l’estat socioeconòmic, el nivell d’urbanització/la ciutat i el temps d’exposició. Els possibles mecanismes investigats eren: l’activitat física (en ENE), l’estrès/restauració, els contactes socials, el soroll i la contaminació atmosfèrica. Els resultats d’aquesta tesi suggereixen que l’exposició a ENE (tant residencial com el contacte amb l’ENE) estava associada positivament amb l’estat de salut dels adults a llarg termini. Les associacions es trobaven sobretot per espais verds i verdor, especialment el verdor circumdant. L’exposició basada-en-event als ENE estava associada positivament als efectes en salut en adults a curt termini. No es va poder concloure res sobre els grups de població que es podien beneficiar més de l’exposició als ENE. L’activitat física podria no ser un mediador de l’associació ENE-salut. La reducció de l’estrès, la restauració i la contaminació atmosfèrica podrien ser mediadors parcials de l’associació. La relació entre exposició a ENE i l’activitat física (en ENE) podria ser modificada per varis factors. Aquesta tesi recalca les limitacions dels estudis existents en el camp i proporciona recomanacions sobre recerca futura. Mentrestant, els planificadors urbans i els legisladors haurien de considerar tots els possibles mecanismes, dirigir-se a tota la població i utilitzar estratègies “només suficientment verdes” acompanyades per polítiques d’anti-gentrificació.
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Douglass, D. Kim. "Quality of experience: a discussion on experiential access to outdoor environments." Thesis, Virginia Tech, 1995. http://hdl.handle.net/10919/40740.
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Douglass, D. Kim (Deborah Kimbrough). "Quality of experience : a discussion on experiential access to outdoor environments /." This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-01242009-063150/.
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Sezginalp, Emre. "Simultaneous Localization And Mapping For A Mobile Robot Operating In Outdoor Environments." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/2/12609191/index.pdf.
Full textAbstract:
In this thesis, a method to the solution of autonomous navigation problem of a robot
working in an outdoor application is sought. The robot will operate in unknown
terrain where there is no a priori map present, and the robot must localize itself while
simultaneously mapping the environment. This is known as Simultaneous
Localization and Mapping (SLAM) problem in the literature. The SLAM problem is
attempted to be solved by using the correlation between range data acquired at
different poses of the robot. A robot operating outdoors will traverse unstructured
terrain, therefore for localization, pitch, yaw and roll angles must also be taken into
account along with the (x,y,z) coordinates of the robot. The Iterative Closest Points
(ICP) algorithm is used to find this transformation between different poses of the
robot and find its location. In order to collect the range data, a system composing of a
laser range finder and an angular positioning system is used. During localization and
mapping, odometry data is fused with range data.
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Chiu, Simon. "Characterization of ultra wideband and propagation in aircraft and outdoor industrial environments." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/14694.
Full textAbstract:
The channel modeling committees of the IEEE 802.15.3 a and 802.15 .4a task groups
devoted considerable effort to developing ultrawideband (UWB) wireless channel
models applicable to systems that operate between 3.1 and 10.6 GHz under both line-ofsight (LOS) and non-line-of-sight (NLOS) conditions in residential, office, outdoor, industrial and body-centric environments at ranges up to 15 m. However, there has been increasing demand for deploying wireless systems in other unconventional environments that have not yet been well characterized. In this thesis, we present four major contributions concerning two such environments: the passenger cabin of a typical midsize airliner and outdoor industrial. First, we have characterized TJWB path gain and
time dispersion over the range 3.1-10.6 GHz within the empty passenger cabin of a
Boeing 737-200 aircraft based on several hundred measured complex channel frequency
responses (CFRs). We found that: (1) the coverage pattern takes the form of chevronshaped contours with path gain decreasing least rapidly along the aisle seats and most rapidly along the window seats, and (2) there is significant advantage to using higher portions of the UWB band for short-range applications and reserving lower portions of the band for longer range applications in such environments. Second, we have characterized the shape of the UWB channel impulse response (CIR) and the fading statistics experienced by individual multipath components (MPCs) over the range 3.1-
10.6 GHz within the Boeing 737-200 aircraft based upon 3300 measured CFRs. We have
also modified the channel simulator developed by IEEE 802.15.4a to generate UWB
CIRs that are representative of those that we observed within the cabin. Third, we have
characterized the effect of human presence on path gain and time dispersion over the
range 3.1-6.1 GHz within the passenger cabin of the Boeing 737-200 aircraft with and
without volunteers in the passenger seats based on a few hundred measured CFRs. We
found that human presence has substantially effects on RF propagation within the aircraft
and that it should be considered when characterizing the performance of in-cabin
wireless systems. Lastly, we present a range-extended VNA-based UWB channel sounder suitable for characterizing UWB propagation in outdoor industrial environments.
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Lim, Hong Meng. "On the average capacity of MIMO channels in outdoor multipath urban environments." Thesis, University of Birmingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420409.
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Figgis, Benjamin. "Investigation of PV soiling and condensation in desert environments via outdoor microscopy." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAD006/document.
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La salissure des modules photovoltaïques (PV) dégrade grandement leurs performances dans les environnements désertiques. Les études précédentes en extérieur ont tendance à trouver de faibles corrélations entre les taux de salissure et les paramètres météorologiques. On pensait que l'une des raisons était le long intervalle de mesure - jours ou semaines - des techniques traditionnelles de mesure des salissures sur le terrain. Dans la présente étude, un «microscope de souillure extérieur» (OSM) a été développé pour mesurer le dépôt et le détachement de particules de poussière individuelles, toutes les 10 minutes, dans des conditions extérieures, de jour comme de nuit. En utilisant une paire d'OSM graissés et non graissés, il était en outre possible de séparer les salissures en trois vitesses de flux de poussière de composants - dépôt, rebondissement immédiat et remise en suspension retardée. Les OSM ont été utilisés pour mesurer les taux de flux dans des expériences sur le terrain à Doha, au Qatar. La nouvelle méthode a révélé des effets explicatifs de paramètres environnementaux qui avaient auparavant été obscurcis par de longs intervalles de mesure des salissures et des taux de flux de poussière confondus. L'OSM pouvait également mesurer l'apparition et la croissance de gouttelettes de condensation microscopiques dans des conditions de terrain et de laboratoire. De telles expériences, ainsi que des mesures isothermes et des analyses de composition, ont démontré que la condensation sur les surfaces sales au terrain d’études était fortement influencée par la présence de matière hygroscopique dans la poussière autre que NaCl. En raison de cette matière, la condensation microscopique peut persister à la surface même si elle est bien supérieure à la température du point de rosée. Les résultats de l'étude suggèrent que la souillure des modules photovoltaïques pourrait être atténuée en tirant parti des variations naturelles des conditions météorologiques au cours de la journéeSoiling of photovoltaic (PV) modules greatly degrades their performance in desert environments. Previous field studies have tended to find weak correlations between the soiling rate and weather parameters. It was thought that one reason was the long measurement interval — days or weeks — of conventional field soiling measurement techniques. In the present study, an “outdoor soiling microscope” (OSM) was developed able to measure deposition and detachment of individual dust particles, every 10 minutes, in outdoor conditions, day and night. By using a greased and ungreased pair of OSMs, it was further possible to separate soiling into three component dust flux rates — deposition, immediate rebound, and delayed resuspension. OSMs were used to measure flux rates in field experiments in Doha, Qatar. The novel method revealed explanatory effects of environmental parameters that had previously been obscured by limits of conventional long soiling measurement intervals and confounded dust flux rates. The OSM could also measure the onset and growth of microscopic condensation droplets in field and laboratory settings. Such experiments, along with isotherm measurements and composition analysis, demonstrated that condensation on soiled surfaces at the test site was strongly influenced by the presence of hygroscopic matter in the dust other than NaCl. Because of such matter, microscopic condensation could persist on both hydrophilic and hydrophobic surfaces well above the dew-point temperature. Results of the study suggest that soiling of PV modules might be mitigated by taking advantage of natural time-of-day variations in weather conditions
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Zou, Jiwei. "Predicting convective heat transfer from Computational Thermal Manikin in urban outdoor environments." Thesis, University of Sydney, 2021. https://hdl.handle.net/2123/24516.
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Urban residents are increasingly encouraged to go outside for recreation and relaxation purposes, which may improve personal health and reduce building energy consumption. It is important to understand the thermal conditions of human body in urban outdoor environments. However, the urban wind conditions at the pedestrian level and their impact on the thermal comfort of people have not been thoroughly investigated to date.
This study aims to predict the convective heat loss from human body subject to urban outdoor wind environments. Onsite wind measurements are carried out at 0.6 m, 1.2 m, and 1.8 m above the ground on three representative green lands in the coastal city of Sydney in Australia. Meanwhile, the effects of the wind velocity and turbulent conditions on the convective heat loss from human body are investigated using a computational thermal manikin (CTM) model, which is validated against published experimental data. Along with empirical equations derived from the CTM simulation, the wind data collected from onsite measurements is used for predicting the convective heat loss from human body in the outdoor wind environments.
In total six groups of wind measurements have been carried out at each measurement sites over a period of four months (from March 2019 to June 2019). The time duration of each measurement is one hour and the sampling frequency is set to 20 Hz. Compared with the local meteorological data recorded at the seaside airport of Sydney, the wind speed in the city is at least 50% lower. To calculate the turbulence characteristics of the wind environment, we use a 1-min averaging period to generate the vertical wind profile of turbulent intensity and turbulence length scale. The correlations between the wind speed and wind turbulence characteristics at different measuring sites are examined. The turbulence intensity measured in this study matches with the reference range given in existing guidelines, while the measured turbulence length scale is much smaller than the value given in the guidelines. It is found that the empirical Von-Karman Spectra can be used to describe the frequency distribution of the turbulence at the pedestrian level in urban open space. The insight of this study regarding the vertical wind profile, turbulence intensity and turbulence length scale at the pedestrian height is beneficial for outdoor thermal comfort assessment.
The results of the present CTM simulation show that the convective heat loss of most body segments increases with increasing wind velocity and turbulent intensity and decreasing turbulence length scale. Empirical correlations for predicting convective heat transfer coefficients as a function of the wind velocity, turbulent intensity and turbulence length scale are derived based on simple-geometry assumptions. It is found that, at a given wind velocity and over the ranges of the turbulence conditions from the field measurements, the variations between the high and low values of the convective heat transfer coefficients can be up to 67%. The results of the CTM simulation demonstrate the significance of capturing the turbulent wind conditions for accurately predicting the heat loss from human body for outdoor thermal comfort studies.
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Rowhani, Shirin. "An investigation of the role of informal play environments for quality outdoor play." Thesis, University of the West of England, Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.557144.
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The role of the outdoor play settings in children's play has long been of interest to the field of planning and design of the built-environment. While a vast body of research has been dedicated to understanding the nature and implications of the design of formal play spaces, such as playgrounds and play centres, very little is known about the characteristics of informal play spaces such as streets that are conducive to quality play. The aim of this study is to develop an evidence-based understanding of the effects of informal play spaces on quality outdoor play. Quality play is determined by the frequency, duration and intensity of play, as well the opportunities available for social interaction and independent mobility. This study proposes a conceptual framework that provides a structure to examine the interaction between three spheres (the built environment characteristics, societal issues, and economic conditions) believed to be critical to help transform the quality of child outdoor play. In this study, recent technology based on accelerometers and tracking devices, together with questionnaire surveys, friendship network mapping exercises, and the built- environment audit, have allowed an accurate, comprehensive and revealing picture of the relationship between the built-environment characteristics and quality of outdoor play. The finding of this study suggests that informal outdoor play spaces support a range of spontaneous, freely chosen, child initiated play activities. The finding reveals that playing in informal spaces, which are not necessarily allocated or designed for play, tends to be associated with longer and more frequent playtime in outdoors, higher levels of physical activity, more interaction between children and extended independent mobility compared with playing in formal spaces. The investigation determined that connectivity of the street networks for pedestrian, natural on-site supervision, and parents' perceptions of neighbourhood safety are positively associated to children's levels of physical activity. Children play more in watched spaces and their levels of sociability are higher in these spaces. The results reflect that the accompaniment of children by adults adversely affects the duration and frequency of their outdoor play.
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Landázuri, Andrea Carolina. "Aerosol Transport Simulations in Indoor and Outdoor Environments using Computational Fluid Dynamics (CFD)." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/612539.
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This dissertation focuses on aerosol transport modeling in occupational environments and mining sites in Arizona using computational fluid dynamics (CFD). The impacts of human exposure in both environments are explored with the emphasis on turbulence, wind speed, wind direction and particle sizes. Final emissions simulations involved the digitalization process of available elevation contour plots of one of the mining sites to account for realistic topographical features. The digital elevation map (DEM) of one of the sites was imported to COMSOL MULTIPHYSICS® for subsequent turbulence and particle simulations. Simulation results that include realistic topography show considerable deviations of wind direction. Inter-element correlation results using metal and metalloid size resolved concentration data using a Micro-Orifice Uniform Deposit Impactor (MOUDI) under given wind speeds and directions provided guidance on groups of metals that coexist throughout mining activities. Groups between Fe-Mg, Cr-Fe, Al-Sc, Sc-Fe, and Mg-Al are strongly correlated for unrestricted wind directions and speeds, suggesting that the source may be of soil origin (e.g. ore and tailings); also, groups of elements where Cu is present, in the coarse fraction range, may come from mechanical action mining activities and saltation phenomenon. Besides, MOUDI data under low wind speeds (<2 m/s) and at night showed a strong correlation for particles 1-micrometer in diameter between the groups: Sc-Be-Mg, Cr-Al, Cu-Mn, Cd-Pb-Be, Cd-Cr, Cu-Pb, Pb-Cd, As-Cd-Pb. The As-Cd-Pb group correlates strongly in almost all ranges of particle sizes. When restricted low wind speeds were imposed more groups of elements are evident and this may be justified with the fact that at lower speeds particles are more likely to settle. When linking these results with CFD simulations and Pb-isotope results it is concluded that the source of elements found in association with Pb in the fine fraction come from the ore that is subsequently processed in the smelter site, whereas the source of elements associated to Pb in the coarse fraction is of different origin. CFD simulation results will not only provide realistic and quantifiable information in terms of potential deleterious effects, but also that the application of CFD represents an important contribution to actual dispersion modeling studies; therefore, Computational Fluid Dynamics can be used as a source apportionment tool to identify areas that have an effect over specific sampling points and susceptible regions under certain meteorological conditions, and these conclusions can be supported with inter-element correlation matrices and lead isotope analysis, especially since there is limited access to the mining sites. Additional results concluded that grid adaption is a powerful tool that allows to refine specific regions that require lots of detail and therefore better resolve flow detail, provides higher number of locations with monotonic convergence than the manual grids, and requires the least computational effort. CFD simulations were approached using the k-epsilon model, with the aid of computer aided engineering software: ANSYS® and COMSOL MULTIPHYSICS®. The success of aerosol transport simulations depends on a good simulation of the turbulent flow. A lot of attention was placed on investigating and choosing the best models in terms of convergence, independence and computational effort. This dissertation also includes preliminary studies of transient discrete phase, eulerian and species transport modeling, importance of saltation of particles, information on CFD methods, and strategies for future directions that should be taken.
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Pasareanu, Stephanie. "A numerical hybrid method for modeling outdoor sound propagation in complex urban environments." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/47601.
Full textAbstract:
Prediction of the sound field in large urban environments has been limited thus far by the heavy computational requirements of conventional numerical methods such as boundary element (BE), finite-difference time-domain (FDTD), or ray-tracing methods. Recently, a considerable amount of work has been devoted to developing energy-based methods for this application, and results have shown the potential to compete with conventional methods. However, these developments have been limited to two-dimensional (2-D) studies (along street axes), and no real description of the phenomena at issue has been exposed (e.g., diffraction effects on the predictions).
The main objectives of the present work were (i) to evaluate the feasibility of an energy-based method, the diffusion model (DM), for sound-field predictions in large, 3-D complex urban environments, (ii) to propose a numerical hybrid method that could improve the accuracy and computational time of these predictions, and (iii) to verify the proposed hybrid method against conventional numerical methods.
The proposed numerical hybrid method consists of a full-wave model coupled with an energy-based model. The full-wave model is used for predicting sound propagation (i) near the source, where constructive and destructive interactions between waves are substantial, and (ii) outside the cluttered environment, where free-field-like conditions apply. The energy-based model is used in regions where diffusion conditions are met. The hybrid approach, as implemented in this work, is a combination of FDTD and DM models.
Results from this work show the role played by diffraction near buildings edges close to the source and near the exterior boundaries of the computational domain, and its impact on the predictions. A wrong modeling of the diffraction effects in the environment leads to significant under or overpredictions of the sound levels in some regions, as compared to conventional numerical methods (in these regions, some differences are as high as 10 dB). The implementation of the hybrid method, verified against a full FDTD model, shows a significant improvement of the predictions. The mean error thus obtained inside the cluttered region of the environment is 1.5 dB.Master of Science
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Ringhov, Evelina, and Sandra Persson. "Förskolepedagogers syn på utomhuspedagogik - Preschool teachers´ view on outdoor education in different environments." Thesis, Malmö högskola, Fakulteten för lärande och samhälle (LS), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-27212.
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Syftet med vår studie är att belysa aktiva förskolepedagogers tankar och funderingar om utomhuspedagogik. En dag på en förskola är inte den andra lik och inte minst pedagogers syn på utevistelse skiljer sig åt. Studien har utgått från frågeställningarna: Vad anser pedagogerna är positivt respektive negativt med utomhuspedagogik? Hur ser den pedagogiska verksamheten ut utomhus? Hur använder pedagogerna sin närmiljö i sin utomhuspedagogik? Tidigare forskning inom området visar att pedagoger anser att utomhuspedagogik tillför något till verksamheten men att intresset och kunskapen inte alltid finns för att verksamheten ska kunna bedrivas utomhus. Materialet till empirin kommer från semistrukturerade intervjuer gjorda med fem aktiva förskolepedagoger på tre olika förskolor i olika kommuner. Intervjuerna är genomförda under våren 2014. Resultatet visar att pedagogerna ser utomhuspedagogik som något positivt och något de gärna använder i sin verksamhet, men ibland räcker inte kunskapen och intresset till. Respondenterna visade en vilja för att använda sin närmiljö i verksamheten och det förekommer en planerad verksamhet när de är på gården men även ute i sin närmiljö. Slutsatsen är att det är pedagogernas intresse, kunskap och engagemang som avgör vilken verksamhet som förekommer utomhus.
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Graham, Shalini L. "Degradation of biomass fuels during long term storage in indoor and outdoor environments." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/29110/.
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This project has investigated the degradation of freshly harvested Willow chips, thermally treated wood pellets and white wood pellets in both indoor and outdoor storage. Novel research has been carried out, by combining a range of fuels, storage scenarios, stockpile sizes and weather/seasonal patterns. A wide spectrum of tests was regularly performed on the stored fuel samples, to determine the extent of chemical, mechanical and biological degradation. The storage trials have been divided into Phase 1 and Phase 2, with Phase 1 starting in April 2011 and Phase 2 in November 2011. The results showed that the extent of chemical degradation was not significant for the different fuels. The main concern for the Willow storage was the high concentration of different fungi on the chips and two pathogenic fungi were identified. In order to fully appreciate the deposition, inhalation and ingestion potential of fungal spores, the release mechanism of the spores from the wood fuels into the air would be recommended as future work. The indoor white wood pellet pile stored in an open barn suffered severe mechanical degradation and it would be therefore advisable to store white wood pellets in a fully enclosed environment with no exposure to ambient temperature and humidity. For the thermally treated pellets, the extent of degradation in the outdoor piles was far more significant than in the indoor one, with rainfall and humidity having an impact on the extent of degradation. Therefore, while the long term storage of thermally treated wood pellets in an open barn with covered storage would be a viable option; pellets stored in outdoor stockpiles would still be vulnerable to mechanical degradation. So outside storage of thermally treated pellets might be an option for short term strategic stocks, but in the majority of cases, covered storage would still be necessary.
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Gemmell, Jon. "The effects of outdoor learning environments on engagement levels of primary school children." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/226152/1/Jon_Gemmell_Thesis.pdf.
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Outdoor Education is colourful and multifaceted with many diverse narratives that account for its growth and complexity. This study has attempted to identify the educational behaviours of students when learning in outdoor environments and determine whether the outdoor setting can influence student engagement with learning. Results suggest that participants do have elevated levels of cognitive, behavioural, and emotional engagement when learning is delivered in an outdoor environment and that they are more enthusiastic and committed to learning. Consequently, this study presents a case that suggests Outdoor Education be considered a pedagogical framework as opposed to a stand-alone subject.
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Ahmed, Md Humayun. "Delay-line-multiplexer-based distributed antenna channel sounders for indoor and outdoor microcellular environments." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58673.
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Distributed Antenna Systems (DAS) are increasingly used to implement wireless access networks that provide high capacity, high reliability, and tailored coverage in both indoor and outdoor microcell environments. The third-generation DAS that have recently emerged are based on massively distributed antennas connected by fibre to transceiver hubs linked via a high-speed backplane. Such systems can be: 1) configured to operate in a variety of operating modes from small cells to Distributed MIMO and 2) highly customized based upon the nature of the environments and the performance demands of the users. Successful deployment of future Distributed Antenna Systems will require channel characterizations that capture our knowledge and understanding of the propagation impairments that degrade the airlink performance in a form useful in simulation and design. The principal challenge of DAS channel measurements is the need to characterize the signals presented by a multiplicity of distributed antennas in an effective and efficient manner. Most DAS channel sounders that have been reported in the literature to date are either based upon a multi-channel measurement receiver or a single-channel receiver equipped with a multi-throw RF switch. Each carries significant penalties in terms of cost and/or performance. Here, we present an alternative scheme that uses relatively inexpensive fibre-optic excess delay lines inserted into a conventional DAS distribution hub in order to effectively stack or multiplex signals in time so they can be presented in sequence by a conventional channel sounder equipped with a single-channel receiver. The concept is generally applicable, with appropriate modification, to channel sounders based upon: 1) Vector Network Analyzers that are commonly used to characterize short-range indoor environments, and 2) stepping or sliding correlators that are commonly used to characterize small cells in outdoor environments. In each case, we have derived system design formulas that allow one to determine the excess delay required to provide adequate temporal separation between the individual channel responses and system error models that allow cross-talk and other effects that may be present in the fiber distribution hub to be characterized. Finally, we have demonstrated proof-of-concept implementations of both in laboratory, real-world indoor, and outdoor small cell environments.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Marklund, Anneli. "Levels and sources of organophosphorus flame retardants and plasticizers in indoor and outdoor environments." Doctoral thesis, Umeå : Dept. of Chemistry, Environmental Chemistry, Univ, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-640.
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Freuder, Tracy Grace. "Designing for the Future: Promoting Ecoliteracy in the Design of Children's Outdoor Play Environments." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/32504.
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Rapid development of U.S. cities and towns along with changes in society and technology are dramatically affecting childhood experience. Wild places and vacant lots for kids to play in are disappearing. Parents have limited time to spend with their children and fear letting them play outside alone. Traffic is a growing safety hazard and there is an increasing desire for entertainment in the form of TV and video games over outdoor exploration. As a result, children are becoming alienated from nature. They are growing up without developing a personal attachment to their natural surroundings or an understanding of their impact on the environment.
The design of outdoor play areas can help reconnect children to their surroundings and lead to a more environmentally minded generation. Ecoliteracy suggests an understanding of ecological principles as well as appreciation for the environment and an attitude of stewardship. In addition to helping kids acquire factual knowledge, outdoor play spaces should cultivate a sense of wonder and delight and an emotional appreciation of the living world. Through research, observation and application, this thesis project identifies design criteria for promoting ecoliteracy in outdoor play environments.Master of Landscape Architecture
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Curran, Alan J. "Reliability of Commercially Relevant Photovoltaic Cell and Packaging Combinations in Accelerated and Outdoor Environments." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1626783783924982.
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Wangchuk, Tenzin. "Quantitative assessment of air quality in different indoor and outdoor environments in rural Bhutan." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/92603/1/Tenzin_Wangchuk_Thesis.pdf.
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The study quantified air quality in different microenvironments in rural Bhutan, for the first time in this mountainous country. The findings clearly demonstrated significant air pollution problems in the microenvironments investigated, originating from diversity of indoor and outdoor sources, and indicating that rural residents in Bhutan are being exposed to high concentrations of multiple pollutants.
The outcomes of the study are of significance in informing policy formulation not only in Bhutan, but also in other developing countries, particularly for Himalayan nations given the shared geographical zones and common cultural and social practices.
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Domingues, Maria Francisca Machado Lima. "The role of open spaces in the future of depopulated urban environments." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25957.
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The number of citizens living in urban areas worldwide is predicted to increase in future decades. However, this projected increase is mainly due to the magnetic power of so-called megacities. Worldwide, many intermediate cities, especially in the most developed countries, have had considerable population losses in the past decades and this trend is expected to continue. When a city loses a high percentage of its population within a short period of time, the traces of that loss become strongly apparent. Abandonment is followed by dereliction, such that the urban fabric can become randomly punctuated with uninhabited spaces where previously present human constructions have been destroyed, and social instability can ensue. The attraction of the city to newcomers then becomes increasingly compromised, and the cycle of decline is harder to overcome. Some cities have developed strategies to redress the situation, such as restricting urban sprawl, demolitions, urban agriculture, rightsizing infrastructure or permitting biodiversity sanctuaries. However, few academic studies have focused on the ways that residents, and potential newcomers, perceive this situation and react to it. Obtaining a deeper understanding of residents¹ perceptions might allow the development of targeted strategies to promote healthier, more attractive and safer environments for these communities, as well as enhancing their potential for newcomers. The research aim, therefore, is to understand the key factors that determine the attractiveness of these urban abandoned spaces for different stakeholder groups, namely, residents of depopulating, and growing, neighbourhoods, and house searchers. Three different methods were used sequentially to explore this quest: interviews with experts, focus groups and conjoint analysis. Conjoint analysis is one of the most robust methods to explore people¹s preferences, by presenting respondents with possible future change scenarios. The study was undertaken in Lisbon (PT) and Genoa (IT), two southern European cities that have experienced population decline, in some areas, in the last three decades. The results of the interviews and focus groups, for both cities, show that while people are naturally resilient to de-densification scenarios, one key concern, when discussing their neighbourhoods in this context, is related to community support. The results from the conjoint analysis corroborate the importance of having a close community for people living in depopulating environments, namely, in Lisbon. The results also show that good quality green spaces are an attraction factor for house searchers. These differences show how the provision of social support in depopulating urban environments might be a determining factor in the stabilization of these neighbourhoods and also, how the presence of good quality green spaces might enhance its attractiveness to newcomers. Social support, therefore, should be given serious consideration in any political, social, architectural intervention within depopulating contexts. Moreover, the presence of green spaces of better quality might be not only a key factor in attracting new residents, but simultaneously, play a crucial role in enhancing the physical and mental health of particularly vulnerable communities, and enhance social interaction.
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Simon, Philippe. "Long-term integrated sampling to characterize airborne volatile organic compounds in indoor and outdoor environments." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq30387.pdf.
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Xiao, Junhao [Verfasser], and Jianwei [Akademischer Betreuer] Zhang. "Planar Segments Based Three-dimensional Robotic Mapping in Outdoor Environments / Junhao Xiao. Betreuer: Jianwei Zhang." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2013. http://d-nb.info/1038788854/34.
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Simon, Philippe 1964. "Long-term integrated sampling to characterize airborne volatile organic compounds in indoor and outdoor environments." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=34455.
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Sampling methods used for the assessment of exposure to volatile organic chemicals (VOCs) in the workplace or for environmental studies are now limited to an upper integrative sampling time of 24 hours or less. Generally, these methods lack versatility and are difficult to use. A passive sampler that can extend sampling periods was developed as part of this research. This novel sampler relies on capillary tubes to restrict and control ambient air entry into an evacuated sample container.A mathematical model was derived by modifications to the Hagen-Poiseuille and ideal gas laws. This model defines the relationship between container volume and capillary geometry (length/internal diameter) required to provide selected sampling times. Based on theoretical considerations, simulations were performed to study the effects of dimensional parameters. From these results, capillaries having 0.05 and 0.10 mm internal diameters were selected according to their ability to reduce sampling flow rates and to increase sampling times. Different capillary lengths were tested on various sampler prototypes. It was found that a constant sampling flow rate was delivered when a maximum discharge rate was established under the influence of a pressure gradient between a vacuum and ambient pressure. Experimental flow rates from 0.018 to 2.6 ml/min were obtained and compared with model predictions. From this comparison, empirical relationships between capillary geometry and maximum discharge rate given by the pressure gradient were defined. Essentially, based on these empirical relationships, capillary sampling flow controller specifications can be calculated to offer extended integrated sampling periods. On this basis, sampler prototypes were configured for stationary sampling and personal sampling.
Studies, based on theory, have indicated that factors such as temperature, humidity and longitudinal molecular diffusion are not likely to influence the passive sampling process. Subsequent experiments confirmed that temperature changes should not significantly affect flow rates delivered by controllers, and that molecular diffusion does not have any impact on the representativeness of long-term samples. Recovery tests provided acceptable results demonstrating that selected capillaries do not contribute to adsorption that could seriously affect the validity of this sampling approach.
Field demonstration studies were performed with both stationary and personal sampler prototypes in the indoor and outdoor environments. The performance of the sampler compared favorably, and in some instances, exceeded that of accepted methodology. These novel samplers were more reliable, had greater versatility and principally, allowed sampling periods extending from hours to a month. These inherent qualities will assist industrial hygienists and environmentalists in the study of emission sources, pollutant concentrations, dispersion, migration and control measures. This novel sampler is presently the only device available for the effective study of episodic events of VOC emission.
Selected capillary geometries acting as a restriction to the entry of ambient air into evacuated sample container can provide a simple, versatile and reliable alternative for the collection of VOCs. This approach can contribute to a better understanding of VOC effects on human health and the environment.
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Metka, Benjamin [Verfasser]. "Robust Visual Self-localization and Navigation in Outdoor Environments Using Slow Feature Analysis / Benjamin Metka." Bielefeld : Universitätsbibliothek Bielefeld, 2019. http://d-nb.info/1201086124/34.
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Fernandes, maligo Artur otavio. "Unsupervised Gaussian mixture models for the classification of outdoor environments using 3D terrestrial lidar data." Thesis, Toulouse, INSA, 2016. http://www.theses.fr/2016ISAT0053/document.
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Le traitement de nuages de points 3D de lidars permet aux robots mobiles autonomes terrestres de construire des modèles sémantiques de l'environnement extérieur dans lequel ils évoluent. Ces modèles sont intéressants car ils représentent des informations qualitatives, et ainsi donnent à un robot la capacité de raisonner à un niveau plus élevé d'abstraction. Le coeur d'un système de modélisation sémantique est la capacité de classifier les observations venant du capteur. Nous proposons un système de classification centré sur l'apprentissage non-supervisé. La prémière couche, la couche intermédiaire, consiste en un modèle de mélange gaussien. Ce modèle est déterminé de manière non-supervisée lors d'une étape de training. Il definit un ensemble de classes intermédiaires qui correspond à une partition fine des classes présentes dans l'environnement. La deuxième couche, la couche finale, consiste en un regroupement des classes intermédiaires dans un ensemble de classes finales qui, elles, sont interprétables dans le contexte de la tâche ciblée. Le regroupement est déterminé par un expert lors de l'étape de training, de manière supervisée, mais guidée par les classes intermédiaires. L'évaluation est basée sur deux jeux de données acquis avec de différents lidars et possédant différentes caractéristiques. L'évaluation est quantitative pour l'un des jeux de données, et qualitative pour l'autre. La concéption du système utilise la procédure standard de l'apprentissage, basée sur les étapes de training, validation et test. L'opération suit la pipeline standard de classification. Le système est simple, et ne requiert aucun pré-traitement ou post-traitementThe processing of 3D lidar point clouds enable terrestrial autonomous mobile robots to build semantic models of the outdoor environments in which they operate. Such models are interesting because they encode qualitative information, and thus provide to a robot the ability to reason at a higher level of abstraction. At the core of a semantic modelling system, lies the capacity to classify the sensor observations. We propose a two-layer classi- fication model which strongly relies on unsupervised learning. The first, intermediary layer consists of a Gaussian mixture model. This model is determined in a training step in an unsupervised manner, and defines a set of intermediary classes which is a fine-partitioned representation of the environment. The second, final layer consists of a grouping of the intermediary classes into final classes that are interpretable in a considered target task. This grouping is determined by an expert during the training step, in a process which is supervised, yet guided by the intermediary classes. The evaluation is done for two datasets acquired with different lidars and possessing different characteristics. It is done quantitatively using one of the datasets, and qualitatively using another. The system is designed following the standard learning procedure, based on a training, a validation and a test steps. The operation follows a standard classification pipeline. The system is simple, with no requirement of pre-processing or post-processing stages