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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Controle ativo de vibrações usando redes neurais artificiais : Active vibration control using artificial neural networks / Active vibration control using artificial neural networks

Ariza Zambrano, William Camilo, 1989- 10 October 2013 (has links)
Orientador: Alberto Luiz Serpa / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-23T23:04:02Z (GMT). No. of bitstreams: 1 ArizaZambrano_WilliamCamilo_M.pdf: 5789145 bytes, checksum: 151f5e3ef1780d5448a7073b85b4715f (MD5) Previous issue date: 2013 / Resumo: Este trabalho tem como objetivo principal o estudo de um método de controle baseado no uso de redes neurais artificiais aplicado ao problema de controle de vibrações em estruturas flexíveis. Este trabalho centra-se no estudo do esquema de controle inverso-direto, que consiste em identificar a dinâmica inversa da planta através de uma rede neural artificial para ser usada como controlador. Três exemplos de aplicação foram resolvidos utilizando-se controladores projetados com o método inverso-direto. A primeira aplicação é o controle de vibrações em uma estrutura mecânica de parâmetros concentrados. O segundo exemplo de aplicação é o controle de vibrações de uma placa engastada em uma de suas extremidades. Neste caso, a placa engastada foi modelada utilizando-se o método de elementos finitos. No seguinte exemplo, o modelo da placa usado no exemplo anterior foi reduzido, deixando apenas os primeiros modos de vibração. No último exemplo tratou-se o problema de controle não colocado das vibrações em uma placa engastada. Os resultados foram analisados a partir da resposta temporal e da resposta em frequência do sistema em malha fechada. Para comparar os resultados obtidos utilizando-se o método de controle baseado em redes neurais artificiais, os exemplos citados anteriormente foram também resolvidos utilizando-se o método de controle ??. Os resultados obtidos demonstram que o método de controle baseado em modelo inverso usando redes neurais foi eficaz na resolução deste tipo de problema / Abstract: The goal of this work is to study a control method based on artificial neural networks applied to the vibration control of flexible structures problem. This work focuses in the direct-inverse control scheme which consists of identifing the inverse dynamics of the plant through an artificial neural network to be used as the controller. Three application examples using the direct-inverse method were solved. The first application is the vibration control in a mechanical structure of concentrated parameters. The second application example is the vibration control of a cantilever plate. The cantilever plate was modeled using the finite elements method. In the third example, a reduction of the cantilever plate model was made. In the last example a non-collocated control problem of vibration in a cantilever plate was treated. The results of the scheme were evaluated according to the temporal response and the frequency response of the closed-loop system. In order to compare the results obtained using the control method based on artificial neural networks, the previous examples were also solved using the ?? control method. The obtained results show that the control method based on inverse model using neural networks was effective in solving this kind of problem / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica
12

Perceptions and attitudes of cow-calf producers toward emerging technologies and policy issues in the beef cattle industry

Breiner, Sharon Jene' January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / Dale A. Blasi / The proposed U.S. National Animal Identification System (US-NAIS) has generated many concerns among beef cattle producers. The goal of the NAIS is to utilize 48-hour traceback in the event of an animal disease outbreak. The traceback would identify all animals that have had contact with the diseased animal, while linking an animal to its premises of origin. According to the Diffusion of Innovation theory, getting a new idea adopted, even when it has clear advantages, is often very difficult. However, by adopting innovations relatively sooner than others in their system, the theory demonstrates marked benefits for innovators and early adopters, as well as a widening of the socioeconomic gap. In this study beef producer demonstrated understanding, acceptance and adaptability to implement the US-NAIS. Participants for the study were selected in the spring of 2006 from a mailing list of cow-calf producers with more than 100 head of cows. BEEF Magazine provided the mailing list and a random sample of 1,000 producers was selected. The results show a knowledge gap between the proposed system and producer understanding. Producers were also divided on support for the proposed system. When ranking their level of support on a scale of 1 to 6, with 1 being strongly supportive and 6 being strongly opposed, 49% of producers showed some level of support and 48% showed some level of opposition, with a mean of 3.53 (s.d. 1.67). Data also highlights a lack of understanding of the regulations and implementation procedures among producers. The results of this study brought considerable insight into the current practices and perceptions of beef cattle producers, and will be used to develop educational materials to improve their understanding of this proposed program.
13

Classification of ocean vessels from low resolution satellite SAR images

Meyer, Rory George Vincent January 2017 (has links)
In the long term it is beneficial to a country's economy to exploit the maritime environment surrounding it responsibly. It is also beneficial to protect this environment from poaching and pollution. To achieve this the responsible parties of a country must have an awareness of what is transpiring in the maritime domain. Synthetic aperture radar can provide an image, regardless of weather or light conditions, of the ocean showing most vessels therein. To monitor the ocean, using synthetic aperture radar imagery, at the lowest cost would require large swath synthetic aperture radar imagery. There exists a trade-off between large swath imagery and the image's resolution resulting in the largest swath image having the poorest resolution. Existing research has shown that it is possible to use coarse resolution synthetic aperture radar imagery to detect vessels at sea, but little work has been done on classifying those vessels. This research aims to investigate the coarse resolution classification information gap. This is done by using a dataset of matching synthetic aperture radar and ship transponder data to train a statistical classification algorithm in order to classify or estimate the length of vessels based on features extracted from their synthetic aperture radar image. The results of this research show that coarse resolution (approximately 40 m per pixel) synthetic aperture radar imagery is able to estimate vessel size for larger classes and provides insight on which vessel classes would require finer resolutions in order to be detected and classified reliably. The range of smaller vessel classes is usually limited to ports and fishing zones. These zones can be mapped using historical vessel transponder data and so a dedicated surveillance campaign can be optimised to use higher resolution products in these areas. The size estimation from the machine learning algorithm performs better than current techniques. / Dissertation (MEng)--University of Pretoria, 2017. / Electrical, Electronic and Computer Engineering / MEng / Unrestricted
14

Modelling marine vessels engaged in wildlife-viewing behaviour using Automatic Identification Systems (AIS)

Nesdoly, Andrea 20 August 2021 (has links)
Observation of marine animals in their environment – whale-watching – has grown greatly in recent years, bringing risk to the animals. Of particular concern are harmful impacts on marine mammals, some of which are endangered. As a result, regulations have been developed for their protection, but these conservation measures require enforcement across a broad geographic region, which is difficult due to limited monitoring resources. A ship-borne information transmission system called AIS – Automatic Identification System – can provide information-rich marine vessel movement data that can be used to passively monitor vessels engaged in viewing wildlife, aiding regulatory bodies with compliance enforcement. Few studies explore the use of AIS data to determine when vessels are engaged in wildlife-viewing, and as such little guidance exists on how to implement classification models appropriately. The objective of this thesis is to use AIS data to evaluate the accuracy and utility of existing classification models to detect vessels engaged in observing wildlife, and determine whether information about species being observed can be extracted. Using a control set of observed cetacean encounter data, three classification models were statistically assessed. From this, a hidden Markov model was chosen for detailed analysis in the vicinity surrounding Vancouver Island, B.C., Canada. The resulting analysis concluded that a hidden Markov unsupervised classification approach was feasible for detecting vessel behaviours and differentiating species type. These findings suggest AIS can aid managers and the commercial whale-watching industry in making informed decisions regarding conservation regulations and their compliance. / Graduate / 2022-08-12
15

The use of the Automated Fingerprint Identification System to improve the quality of service rendered by the South African Police Service on the East Rand

Matlala, Mpho Mark 2012 November 1900 (has links)
The globalisation process that drives the progression and trans-national nature of crime requires that the police should use sophisticated and/or state-of-the art technologies to help them to combat criminality. The use of technology by the police is thus viewed as one of the appropriate responses to deal with the threats posed by crime. In an attempt to ascertain the significance of technology in police work, this research examined the impact that the use of biometric technology such as the Automated Fingerprint Identification System, has had on the quality of seiVices rendered by the South African Police Service. Following the police's task of identifying criminal fingerprints, the problem encountered in this research was that, ever since the introduction of the Automated Fingerprint Identification System, no research had been conducted to assess the impact thereof on the level and quality of seiVices rendered by the South African Police SeiVice. This problem was further intensified by the fact that there was no framework to assess the impact that the utilisation of the Automated Fingerprint Identification System has had on police work in South Africa. Consequently, the problems that were identified in this research compromised not only the quality of seiVices rendered by the police, but also the safety and security within communities. The findings in this research showed that the utilisation of biometric technologies such as the Automated Fingerprint Identification System have helped the police to accurately identify and arrest criminal suspects. However, some of the conclusions reached suggested that the quantitative aspect of the utilisation of biometric systems and the elated portable apparatuses within the South African Police Service was emphasised more than the qualitative aspect thereof. The emphasis was evident in the statistics regarding the use of the Automated Fingerprint Identification System, which focused primarily on police productivity and to a lesser degree on accountability related issues. This study espoused a qualitative paradigm and the investigations in the research were focused on the East Rand policing precinct. The participants who informed this research were selected from the research population using random and purposive sampling techniques. In the same way, the data that informed this research was collected using semi-structured interviews and an in-depth review of the literature on policing and its utilisation of the different technologies. The research espoused social constructivism and phenomenology as the philosophical worldviews of choice to form constructivist phenomenology and to attain theoretical triangulation. Moreover, evaluation research and a case study were espoused as the research designs of choice, to attain methodological triangulation. The various triangulation techniques espoused in this research project were critical in attaining quality assurance in terms of the research methodology applied. In the same way, a myriad of qualitative techniques such as dependability, transferability, confimability and credibility were also employed in order to ensure that the integrity of the data that was collected in this study remained intact. Finally, the data that was collected to inform this research was analysed using the qualitative content analysis technique. Similarly, the measures taken to ensure that the safety of the research participants was delineated in this same research report. / Police Practice / M. Tech. (Police Science)
16

The use of the Automated Fingerprint Identification System to improve the quality of service rendered by the South African Police Service on the East Rand

Matlala, Mpho Mark 11 1900 (has links)
The globalisation process that drives the progression and trans-national nature of crime requires that the police should use sophisticated and/or state-of-the art technologies to help them to combat criminality. The use of technology by the police is thus viewed as one of the appropriate responses to deal with the threats posed by crime. In an attempt to ascertain the significance of technology in police work, this research examined the impact that the use of biometric technology such as the Automated Fingerprint Identification System, has had on the quality of seiVices rendered by the South African Police Service. Following the police's task of identifying criminal fingerprints, the problem encountered in this research was that, ever since the introduction of the Automated Fingerprint Identification System, no research had been conducted to assess the impact thereof on the level and quality of seiVices rendered by the South African Police SeiVice. This problem was further intensified by the fact that there was no framework to assess the impact that the utilisation of the Automated Fingerprint Identification System has had on police work in South Africa. Consequently, the problems that were identified in this research compromised not only the quality of seiVices rendered by the police, but also the safety and security within communities. The findings in this research showed that the utilisation of biometric technologies such as the Automated Fingerprint Identification System have helped the police to accurately identify and arrest criminal suspects. However, some of the conclusions reached suggested that the quantitative aspect of the utilisation of biometric systems and the elated portable apparatuses within the South African Police Service was emphasised more than the qualitative aspect thereof. The emphasis was evident in the statistics regarding the use of the Automated Fingerprint Identification System, which focused primarily on police productivity and to a lesser degree on accountability related issues. This study espoused a qualitative paradigm and the investigations in the research were focused on the East Rand policing precinct. The participants who informed this research were selected from the research population using random and purposive sampling techniques. In the same way, the data that informed this research was collected using semi-structured interviews and an in-depth review of the literature on policing and its utilisation of the different technologies. The research espoused social constructivism and phenomenology as the philosophical worldviews of choice to form constructivist phenomenology and to attain theoretical triangulation. Moreover, evaluation research and a case study were espoused as the research designs of choice, to attain methodological triangulation. The various triangulation techniques espoused in this research project were critical in attaining quality assurance in terms of the research methodology applied. In the same way, a myriad of qualitative techniques such as dependability, transferability, confimability and credibility were also employed in order to ensure that the integrity of the data that was collected in this study remained intact. Finally, the data that was collected to inform this research was analysed using the qualitative content analysis technique. Similarly, the measures taken to ensure that the safety of the research participants was delineated in this same research report. / Police Practice / M. Tech. (Police Science)
17

The use of Automated Fingerprint Identification System in identifying fraudulent voters’ registration in Lesotho

Chigando, Lesole John January 2018 (has links)
The research was prompted by constant criticism of the Independent Electoral Commission (IEC) because of its poor voter registration and voters’ roll. Free and fair elections are the strong arm of democracy. The identified research problem was investigated by means of qualitative research. A thorough literature study from various sources of information, a case file analysis and structured interviews were used to gather the required data. The interviews were conducted with fingerprint experts, a data processor and constituency electoral assistants from the Lesotho Mounted Police Service, the National Identity and Civil Registry at the Ministry of Home Affairs and the IEC respectively. It was found that using fingerprints and the Automated Fingerprint Identification System (AFIS) can assist in investigations and in combating voter’s fraud, as fingerprints are unique. AFIS can be utilised for various purposes by institutions in the private and public sectors. Like any apparatus, AFIS has its own strengths and weaknesses. / Criminology and Security Science / M. Tech. (Forensic investigation)
18

AIS i havets och tankens strömmar : En etnografisk studie av nautikers användning av transpondersystemet AIS / AIS in The Currents of Sea and Thought : An ethnographic study of mariners'use of the Automatic Identification System

Blomberg, Olle January 2004 (has links)
An ethnographic study loosely informed by the theoretical framework of distributed cognition was carried out in order to describe how mariners have adopted the Automatic Identification System (AIS) in their work practice, or"made the technology their own". AIS is a transponder-based identification and communication system that allows ships to automatically identify and track each other. In addition to facilitating the identification and tracking of ships, objectives behind the introduction of AIS are to"simplify informational exchange", and"provide additional information to assist situation awareness". Participant observation and interviews were made at four different ships, as well as at two shore stations. A focus group was also held at a maritime conference. The study gave some interesting results. For example, a Problem of Public Information Loss was identified. It is tentatively suggested that this problem has been overlooked partly because of a widespread but impoverished model of communication which does not account for the role of side-participants in a conversation. It is concluded that more research needs to be done on maritime work and the use of new bridge technology.
19

Electronic animal identification systems at livestock auction markets: perceptions, costs, and benefits

Bolte, Kati Jo January 1900 (has links)
Master of Science / Department of Agricultural Economics / Ted C. Schroeder / Electronic animal identification systems are becoming more common in livestock auction markets because of increased numbers of cattle being electronically identified. More cattle are being individually identified because of increasing enrollment in marketing alliances and verification programs. Also, the National Animal Identification System (NAIS) has increased awareness and perhaps use of electronic identification. In this study, individual characteristics of livestock markets were analyzed to determine how they relate to a livestock market operator's views, concerns, and knowledge of the NAIS as well as adoption of RFID reading equipment. Investments in RFID tagging services and RFID reading equipment by livestock markets were estimated and price premiums associated with RFID tagged and preconditioned cattle were estimated. Data were from a national survey of livestock auction markets and cattle transaction data were obtained from three Kansas livestock markets. Auction markets that indicated they currently plan to add a RFID tagging service are likely to have more knowledge of the NAIS program standards, how to adopt the NAIS practices, and the probable costs involved. Managers of facilities that sell a large volume of livestock annually tend to have a higher level of understanding of how to adopt the NAIS practices and be more knowledgeable of the NAIS standards than operators of smallvolume facilities. Managers of markets that have operating RFID reader systems tend to be more understanding of how to adopt the NAIS practices and of costs associated with adopting the NAIS. Livestock market managers tend to be highly concerned that adoption of individual animal identification systems will adversely impact sale speed and tend to view the NAIS as a threat to their business. Large volume facilities, facilities that have registered their premises, and facilities that plan to add a RFID tagging service are more likely to adopt RFID reader systems. Economies of scale exist in RFID system adoption and RFID tagging services for auction markets. Preconditioned and RFID tagged cattle brought a significant premium at only one of three facilities where data were collected.
20

Developing and applying precision animal farming tools for poultry behavior monitoring

Li, Guoming 30 April 2021 (has links)
Appropriate measurement of broiler behaviors is critical to optimize broiler production efficiency and improve precision management strategies. However, performance of different precision tools on measuring broiler behaviors of interest remains unclear. This dissertation systematically developed and evaluated radio frequency identification (RFID) system, image processing, and deep learning for automatically detecting and analyzing broiler behaviors. Then different behaviors (i.e., feeding, drinking, stretching, restricted feeding) of broilers under representative management practices were measured using the developed precision tools. The broilers were Ross 708 in weeks 4-8. The major findings show that the RFID system achieved high performance (over 90% accuracy) for continuously tracking feeding and drinking behaviors of individual broilers, after they were customized and modified, such as tag sensitivity test, power adjustment, radio wave shielding, and assessment of interference by add-ons. The image processing algorithms combined with a machine learning model were customized and adjusted based on the experimental conditions and finally achieved 85% sensitivity, specificity, and accuracy for detecting bird number at feeder and at drinkers. After adjusting labeling method and hyperparameter tuning, the faster region-based convolutional neural network (faster R-CNN) had over 86% precision, recall, specificity, and accuracy for detecting broiler stretching behaviors. In comprehensive algorithms, the faster R-CNN showed over 92% precision, recall, and F1 score for detecting feeder, eating birds, and birds around feeder. The bird trackers had a 3.2% error rate to track individual birds around feeder. The support vector machine behavior classifier achieved over 92% performance for classifying walking birds. Image processing model was also developed to detect birds that were restricted to feeder access. Broilers had different behavior responses to different sessions of a day, bird ages, environments, diets, and allocated resources. Reducing stocking density, increasing feeder space, and applying poultry-specific light spectrum and intensity were beneficial for birds to perform behaviors, such as feeding, drinking, and stretching, while using the antibiotics-free diet reduced bird feeding time. In conclusion, the developed tools are useful tools for automated broiler behavior monitoring and the measured behavior responses provide insights into precision management of welfare-oriented broiler production.

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