221 research outputs found
Vehicle Engine Classification Using of Laser Vibrometry Feature Extraction
Used as a non-invasive and remote sensor, the laser Doppler vibrometer (LDV) has been used in many different applications, such as inspection of aircrafts, bridge and structure and remote voice acquisition. However, using LDV as a vehicle surveillance device has not been feasible due to the lack of systematic investigations on its behavioral properties. In this thesis, the LDV data from different vehicles are examined and features are extracted. A tone-pitch indexing (TPI) scheme is developed to classify different vehicles by exploiting the engine’s periodic vibrations that are transferred throughout the vehicle’s body. Using the TPI with a two-layer feed-forward 20 intermediate-nodes neural network to classify vehicles’ engine, the results are encouraging as they can consistently achieve accuracies over 96%. However, the TPI required a length of 1.25 seconds of vibration, which is a drawback of the TPI, as vehicles generally are moving whence the 1.25 second signals are unavailable. Based on the success of TPI, a new normalized tone-pitch indexing (nTPI) scheme is further developed, using the engine’s periodic vibrations, and shortened the time period from 1.25 seconds to a reasonable 0.2 seconds. Keywords: LDV, Machine Learning, Neural network, Deep learning, Vehicle classificatio
A Hybrid Kinematic-Acoustic System for Automated Activity Detection of Construction Equipment
Automatically recognizing and tracking construction equipment activities is the first step towards performance monitoring of a job site. Recognizing equipment activities helps construction managers to detect the equipment downtime/idle time in a real-time framework, estimate the productivity rate of each equipment based on its progress, and efficiently evaluate the cycle time of each activity. Thus, it leads to project cost reduction and time schedule improvement. Previous studies on this topic have been based on single sources of data (e.g., kinematic, audio, video signals) for automated activity-detection purposes. However, relying on only one source of data is not appropriate, as the selected data source may not be applicable under certain conditions and fails to provide accurate results. To tackle this issue, the authors propose a hybrid system for recognizing multiple activities of construction equipment. The system integrates two major sources of data-audio and kinematic-through implementing a robust data fusion procedure. The presented system includes recording audio and kinematic signals, preprocessing data, extracting several features, as well as dimension reduction, feature fusion, equipment activity classification using Support Vector Machines (SVM), and smoothing labels. The proposed system was implemented in several case studies (i.e., ten different types and equipment models operating at various construction job sites) and the results indicate that a hybrid system is capable of providing up to 20% more accurate results, compared to cases using individual sources of data
Index to 1986 NASA Tech Briefs, volume 11, numbers 1-4
Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1986 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences
Sound based social networks
The sound environment is an eco of the activity and character of each
place, often carrying additional information to that made available to the eyes
(both new and redundant). It is, therefore, an intangible and volatile acoustic
fingerprint of the place, or simply an acoustic snapshot of a single event. Such
rich resource, full of meaning and subtleness, Schaeffer called Soundscape.
The exploratory research project presented here addresses the Soundscape
in the context of Mobile Online Social Networking, aiming at determining the
extent of its applicability regarding the establishment and/or strengthening of
new and existing social links. Such research goal demanded an interdisciplinary
approach, which we have anchored in three main stems: Soundscapes,
Mobile Sound and Social Networking. These three areas pave the scientific
ground for this study and are introduced during the first part of the thesis. An
extensive survey of the state-of-the-arte projects related with this research is
also presented, gathering examples from different but adjacent areas such as
mobile sensing, wearable computing, sonification, social media and contextaware
computing. This survey validates that our approach is scientifically opportune
and unique, at the same time.
Furthermore, in order to assess the role of Soundscapes in the context
of Social Networking, an experimental procedure has been implemented
based on an Online Social Networking mobile application, enriched with environmental
sensing mechanisms, able to capture and analyze the surrounding
Soundscape and users' movements. Two main goals guided this prototypal
research tool: collecting data regarding users' activity (both sonic and kinetic)
and providing users with a real experience using a Sound-Based Social Network,
in order to collect informed opinions about this unique type of Social
Networking. The application – Hurly-Burly – senses the surrounding Soundscape
and analyzes it using machine audition techniques, classifying it according
to four categories: speech, music, environmental sounds and silence. Additionally, it determines the sound pressure level of the sensed Soundscape
in dB(A)eq. This information is then broadcasted to the entire online social
network of the user, allowing each element to visualize and audition a representation
of the collected data. An individual record for each user is kept
available in a webserver and can be accessed through an online application,
displaying the continuous acoustic profile of each user along a timeline graph.
The experimental procedure included three different test groups, forming each
one a social network with a cluster coefficient equal to one.
After the implementation and result analysis stages we concluded that
Soundscapes can have a role in the Online Social Networking paradigm, specially
when concerning mobile applications. Has been proven that current offthe-
shelf mobile technology is a promising opportunity for accomplishing this
kind of tasks (such as continuous monitoring, life logging and environment
sensing) but battery limitations and multitasking's constraints are still the bottleneck,
hindering the massification of successful applications. Additionally,
online privacy is something that users are not enthusiastic in letting go: using
captured sound instead of representations of the sound would abstain users
from utilizing such applications. We also demonstrated that users who are
more aware of the Soundscape concept are also more inclined to assume it
as playing an important role in OSN. This means that more pedagogy towards
the acoustic phenomenon is needed and this type of research gives a step
further in that direction.O ambiente sonoro de um lugar é um eco da sua atividade e carácter,
transportando, na maior parte da vezes, informação adicional àquela que é
proporcionada à visão (quer seja redundante ou complementar). É, portanto,
uma impressão digital acústica - tangível e volátil - do lugar a que pertence,
ou simplesmente uma fotografia acústica de um evento pontual. A este opulento
recurso, carregado de significados e subtilezas, Schafer chamou de
Paisagem-Sonora. O projeto de investigação de carácter exploratório que
aqui apresentamos visa o estudo da Paisagem-Sonora no contexto das Redes
Sociais Móveis Em-Linha, procurando entender os moldes e limites da
sua aplicação, tendo em vista o estabelecimento e/ou reforço de novos ou
existente laços sociais, respectivamente. Para satisfazer este objectivo foi
necessária uma abordagem multidisciplinar, ancorada em três pilares principais:
a Paisagem-Sonora, o Som Móvel e as Redes Sociais. Estas três áreas
determinaram a moldura científica de referência em que se enquadrou esta
investigação, sendo explanadas na primeira parte da tese. Um extenso levantamento
do estado-da-arte referente a projetos relacionados com este estudo
é também apresentado, compilando exemplos de áreas distintas mas adjacentes,
tais como: Computação Sensorial Móvel, Computação Vestível, Sonificação,
Média Social e Computação Contexto-Dependente. Este levantamento
veio confirmar quer a originalidade quer a pertinência científica do projeto
apresentado.
Posteriormente, a fim de avaliar o papel da Paisagem-Sonora no contexto
das Redes Sociais, foi posto em prática um procedimento experimental
baseado numa Rede Social Sonora Em-Linha, desenvolvida de raiz para dispositivos
móveis e acrescida de mecanismos sensoriais para estímulos ambientais,
capazes de analisar a Paisagem-Sonora envolvente e os movimentos
do utilizador. Dois objectivos principais guiaram a produção desta ferramenta
de investigação: recolher dados relativos à atividade cinética e sonora dos utilizadores e proporcionar a estes uma experiência real de utilização
uma Rede Social Sonora, de modo a recolher opiniões fundamentadas sobre
esta tipologia específica de socialização. A aplicação – Hurly-Burly – analisa
a Paisagem-Sonora através de algoritmos de Audição Computacional, classificando-
a de acordo com quatro categorias: diálogo (voz), música, sons ambientais
(“ruídos”) e silêncio. Adicionalmente, determina o seu nível de pressão
sonora em dB(A)eq. Esta informação é então distribuída pela rede social
dos utilizadores, permitindo a cada elemento visualizar e ouvir uma representação
do som analisado. É mantido num servidor Web um registo individual
da informação sonora e cinética captada, o qual pode ser acedido através de
uma aplicação Web que mostra o perfil sonoro de cada utilizador ao longo do
tempo, numa visualização ao estilo linha-temporal. O procedimento experimental
incluiu três grupos de teste distintos, formando cada um a sua própria
rede social com coeficiente de aglomeração igual a um. Após a implementação
da experiência e análise de resultados, concluímos que a Paisagem-
Sonora pode desempenhar um papel no paradigma das Redes Sociais Em-
Linha, em particular no que diz respeito à sua presença nos dispositivos móveis.
Ficou provado que os dispositivos móveis comerciais da atualidade
apresentam-se com uma oportunidade promissora para desempenhar este
tipo de tarefas (tais como: monitorização contínua, registo quotidiano e análise
sensorial ambiental), mas as limitações relacionadas com a autonomia
energética e funcionamento em multitarefa representam ainda um constrangimento
que impede a sua massificação. Além disso, a privacidade no mundo
virtual é algo que os utilizadores atuais não estão dispostos a abdicar: partilhar
continuamente a Paisagem-Sonora real em detrimento de uma representação
de alto nível é algo que refrearia os utilizadores de usar a aplicação.
Também demonstrámos que os utilizadores que mais conhecedores do fenómeno
da Paisagem-Sonora são também os que consideram esta como importante
no contexto das Redes Sociais Em-Linha. Isso significa que uma atitude
pedagógica em relação ao fenómeno sonoro é essencial para obter dele
o maior ganho possível. Esta investigação propõe-se a dar um passo em
frente nessa direção
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