7 research outputs found
Flood Forecasting Using Machine Learning Methods
This book is a printed edition of the Special Issue Flood Forecasting Using Machine Learning Methods that was published in Wate
Application of Artificial Intelligence algorithms to support decision-making in agriculture activities
Deep Learning has been successfully applied to image recognition, speech recognition, and
natural language processing in recent years. Therefore, there has been an incentive to apply
it in other fields as well. The field of agriculture is one of the most important in which the
application of artificial intelligence algorithms, and particularly, of deep learning needs to
be explored, as it has a direct impact on human well-being. In particular, there is a need
to explore how deep learning models for decision-making can be used as a tool for optimal
planting, land use, yield improvement, production/disease/pest control, and other activities.
The vast amount of data received from sensors in smart farms makes it possible to use deep
learning as a model for decision-making in this field. In agriculture, no two environments are
exactly alike, which makes testing, validating, and successfully implementing such technologies
much more complex than in most other sectors. Recent scientific developments in the
field of deep learning, applied to agriculture, are reviewed and some challenges and potential
solutions using deep learning algorithms in agriculture are discussed. Higher performance
in terms of accuracy and lower inference time can be achieved, and the models can be made
useful in real-world applications. Finally, some opportunities for future research in this area
are suggested. The ability of artificial neural networks, specifically Long Short-Term Memory
(LSTM) and Bidirectional LSTM (BLSTM), to model daily reference evapotranspiration
and soil water content is investigated. The application of these techniques to predict these
parameters was tested for three sites in Portugal. A single-layer BLSTM with 512 nodes was
selected. Bayesian optimization was used to determine the hyperparameters, such as learning
rate, decay, batch size, and dropout size. The model achieved mean square error (MSE)
values ranging from 0.07 to 0.27 (mm d–1)² for ETo (Reference Evapotranspiration) and
0.014 to 0.056 (m³m–3)² for SWC (Soil Water Content), with R2 values ranging from 0.96
to 0.98. A Convolutional Neural Network (CNN) model was added to the LSTM to investigate
potential performance improvement. Performance dropped in all datasets due to the
complexity of the model. The performance of the models was also compared with CNN, traditional
machine learning algorithms Support Vector Regression, and Random Forest. LSTM
achieved the best performance. Finally, the impact of the loss function on the performance
of the proposed models was investigated. The model with the mean square error (MSE) as
loss function performed better than the model with other loss functions. Afterwards, the
capabilities of these models and their extension, BLSTM and Bidirectional Gated Recurrent
Units (BGRU) to predict end-of-season yields are investigated. The models use historical
data, including climate data, irrigation scheduling, and soil water content, to estimate endof-
season yield. The application of this technique was tested for tomato and potato yields at a
site in Portugal. The BLSTM network outperformed the GRU, the LSTM, and the BGRU networks
on the validation dataset. The model was able to capture the nonlinear relationship
between irrigation amount, climate data, and soil water content and predict yield with an
MSE of 0.017 to 0.039 kg/ha. The performance of the BLSTM in the test was compared with
the most commonly used deep learning method called CNN, and machine learning methods
including a Multi-Layer Perceptrons model and Random Forest regression. The BLSTM out-performed the other models with a R2-score between 0.97 and 0.99. The results show that
analyzing agricultural data with the LSTM model improves the performance of the model in
terms of accuracy. The CNN model achieved the second-best performance. Therefore, the
deep learning model has a remarkable ability to predict the yield at the end of the season. Additionally,
a Deep Q-Network was trained for irrigation scheduling. The agent was trained to
schedule irrigation for a tomato field in Portugal. Two LSTM models trained previously were
used as the agent environment. One predicts the total water in the soil profile on the next
day. The other one was employed to estimate the yield based on the environmental condition
during a season and then measure the net return. The agent uses this information to decide
the following irrigation amount. LSTM and CNN networks were used to estimate the Q-table
during training. Unlike the LSTM model, the ANN and the CNN could not estimate the Qtable,
and the agent’s reward decreased during training. The comparison of the performance
of the model was done with fixed-base irrigation and threshold-based irrigation. The trained
model increased productivity by 11% and decreased water consumption by 20% to 30% compared
to the fixed method. Also, an on-policy model, Advantage Actor–Critic (A2C), was
implemented to compare irrigation scheduling with Deep Q-Network for the same tomato
crop. The results show that the on-policy model A2C reduced water consumption by 20%
compared to Deep Q-Network with a slight change in the net reward. These models can be
developed to be applied to other cultures with high importance in Portugal, such as fruit,
cereals, and grapevines, which also have large water requirements. The models developed
along this thesis can be re-evaluated and trained with historical data from other cultures with
high production in Portugal, such as fruits, cereals, and grapes, which also have high water
demand, to create a decision support and recommendation system that tells farmers when
and how much to irrigate. This system helps farmers avoid wasting water without reducing
productivity. This thesis aims to contribute to the future steps in the development of precision
agriculture and agricultural robotics. The models developed in this thesis are relevant to
support decision-making in agricultural activities, aimed at optimizing resources, reducing
time and costs, and maximizing production.Nos últimos anos, a técnica de aprendizagem profunda (Deep Learning) foi aplicada com
sucesso ao reconhecimento de imagem, reconhecimento de fala e processamento de linguagem
natural. Assim, tem havido um incen tivo para aplicá-la também em outros sectores.
O sector agrícola é um dos mais importantes, em que a aplicação de algoritmos de inteligência
artificial e, em particular, de deep learning, precisa ser explorada, pois tem impacto direto
no bem-estar humano. Em particular, há uma necessidade de explorar como os modelos de
aprendizagem profunda para a tomada de decisão podem ser usados como uma ferramenta
para cultivo ou plantação ideal, uso da terra, melhoria da produtividade, controlo de produção,
de doenças, de pragas e outras atividades. A grande quantidade de dados recebidos
de sensores em explorações agrícolas inteligentes (smart farms) possibilita o uso de deep
learning como modelo para tomada de decisão nesse campo. Na agricultura, não há dois
ambientes iguais, o que torna o teste, a validação e a implementação bem-sucedida dessas
tecnologias muito mais complexas do que na maioria dos outros setores. Desenvolvimentos
científicos recentes no campo da aprendizagem profunda aplicada à agricultura, são revistos
e alguns desafios e potenciais soluções usando algoritmos de aprendizagem profunda na agricultura
são discutidos. Maior desempenho em termos de precisão e menor tempo de inferência
pode ser alcançado, e os modelos podem ser úteis em aplicações do mundo real. Por fim,
são sugeridas algumas oportunidades para futuras pesquisas nesta área. A capacidade de redes
neuronais artificiais, especificamente Long Short-Term Memory (LSTM) e LSTM Bidirecional
(BLSTM), para modelar a evapotranspiração de referência diária e o conteúdo de água
do solo é investigada. A aplicação destas técnicas para prever estes parâmetros foi testada em
três locais em Portugal. Um BLSTM de camada única com 512 nós foi selecionado. A otimização
bayesiana foi usada para determinar os hiperparâmetros, como taxa de aprendizagem,
decaimento, tamanho do lote e tamanho do ”dropout”. O modelo alcançou os valores de erro
quadrático médio na faixa de 0,014 a 0,056 e R2 variando de 0,96 a 0,98. Um modelo de
Rede Neural Convolucional (CNN – Convolutional Neural Network) foi adicionado ao LSTM
para investigar uma potencial melhoria de desempenho. O desempenho decresceu em todos
os conjuntos de dados devido à complexidade do modelo. O desempenho dos modelos
também foi comparado com CNN, algoritmos tradicionais de aprendizagem máquina Support
Vector Regression e Random Forest. O LSTM obteve o melhor desempenho. Por fim,
investigou-se o impacto da função de perda no desempenho dos modelos propostos. O modelo
com o erro quadrático médio (MSE) como função de perda teve um desempenho melhor
do que o modelo com outras funções de perda. Em seguida, são investigadas as capacidades
desses modelos e sua extensão, BLSTM e Bidirectional Gated Recurrent Units (BGRU) para
prever os rendimentos da produção no final da campanha agrícola. Os modelos usam dados
históricos, incluindo dados climáticos, calendário de rega e teor de água do solo, para estimar
a produtividade no final da campanha. A aplicação desta técnica foi testada para os rendimentos
de tomate e batata em um local em Portugal. A rede BLSTM superou as redes GRU,
LSTM e BGRU no conjunto de dados de validação. O modelo foi capaz de captar a relação não
linear entre dotação de rega, dados climáticos e teor de água do solo e prever a produtividade com um MSE variando de 0,07 a 0,27 (mm d–1)² para ETo (Evapotranspiração de Referência)
e de 0,014 a 0,056 (m³m–3)² para SWC (Conteúdo de Água do Solo), com valores de R2
variando de 0,96 a 0,98. O desempenho do BLSTM no teste foi comparado com o método de
aprendizagem profunda CNN, e métodos de aprendizagem máquina, incluindo um modelo
Multi-Layer Perceptrons e regressão Random Forest. O BLSTM superou os outros modelos
com um R2 entre 97% e 99%. Os resultados mostram que a análise de dados agrícolas
com o modelo LSTM melhora o desempenho do modelo em termos de precisão. O modelo
CNN obteve o segundo melhor desempenho. Portanto, o modelo de aprendizagem profunda
tem uma capacidade notável de prever a produtividade no final da campanha. Além disso,
uma Deep Q-Network foi treinada para programação de irrigação para a cultura do tomate.
O agente foi treinado para programar a irrigação de uma plantação de tomate em Portugal.
Dois modelos LSTM treinados anteriormente foram usados como ambiente de agente. Um
prevê a água total no perfil do solo no dia seguinte. O outro foi empregue para estimar a produtividade
com base nas condições ambientais durante uma o ciclo biológico e então medir
o retorno líquido. O agente usa essas informações para decidir a quantidade de irrigação.
As redes LSTM e CNN foram usadas para estimar a Q-table durante o treino. Ao contrário
do modelo LSTM, a RNA e a CNN não conseguiram estimar a tabela Q, e a recompensa do
agente diminuiu durante o treino. A comparação de desempenho do modelo foi realizada
entre a irrigação com base fixa e a irrigação com base em um limiar. A aplicação das doses
de rega preconizadas pelo modelo aumentou a produtividade em 11% e diminuiu o consumo
de água em 20% a 30% em relação ao método fixo. Além disso, um modelo dentro da táctica,
Advantage Actor–Critic (A2C), é foi implementado para comparar a programação de
irrigação com o Deep Q-Network para a mesma cultura de tomate. Os resultados mostram
que o modelo de táctica A2C reduziu o consumo de água consumo em 20% comparado ao
Deep Q-Network com uma pequena mudança na recompensa líquida. Estes modelos podem
ser desenvolvidos para serem aplicados a outras culturas com elevada produção em Portugal,
como a fruta, cereais e vinha, que também têm grandes necessidades hídricas. Os modelos
desenvolvidos ao longo desta tese podem ser reavaliados e treinados com dados históricos
de outras culturas com elevada importância em Portugal, tais como frutas, cereais e uvas,
que também têm elevados consumos de água. Assim, poderão ser desenvolvidos sistemas
de apoio à decisão e de recomendação aos agricultores de quando e quanto irrigar. Estes
sistemas poderão ajudar os agricultores a evitar o desperdício de água sem reduzir a produtividade.
Esta tese visa contribuir para os passos futuros na evolução da agricultura de
precisão e da robótica agrícola. Os modelos desenvolvidos ao longo desta tese são relevantes
para apoiar a tomada de decisões em atividades agrícolas, direcionadas à otimização de recursos,
redução de tempo e custos, e maximização da produção.Centro-01-0145-FEDER000017-EMaDeS-Energy,
Materials, and Sustainable Development, co-funded by the Portugal 2020 Program (PT 2020),
within the Regional Operational Program of the Center (CENTRO 2020) and the EU through
the European Regional Development Fund (ERDF). Fundação para a Ciência e a Tecnologia
(FCT—MCTES) also provided financial support via project UIDB/00151/2020 (C-MAST).
It was also supported by the R&D Project BioDAgro – Sistema operacional inteligente de
informação e suporte á decisão em AgroBiodiversidade, project PD20-00011, promoted by
Fundação La Caixa and Fundação para a Ciência e a Tecnologia, taking place at the C-MAST
- Centre for Mechanical and Aerospace Sciences and Technology, Department of Electromechanical
Engineering of the University of Beira Interior, Covilhã, Portugal
Climate Change and Environmental Sustainability-Volume 2
Our world is facing many challenges, such as poverty, hunger, resource shortage, environmental degradation, climate change, and increased inequalities and conflicts. To address such challenges, the United Nations proposed the Sustainable Development Goals (SDG), consisting of 17 interlinked global goals, as the strategic blueprint of world sustainable development. Nevertheless, the implementation of the SDG framework has been very challenging and the COVID-19 pandemic has further impeded the SDG implementation progress. Accelerated efforts are needed to enable all stakeholders, ranging from national and local governments, civil society, private sector, academia and youth, to contribute to addressing this dilemma. This volume of the Climate Change and Environmental Sustainability book series aims to offer inspiration and creativity on approaches to sustainable development. Among other things, it covers topics of COVID-19 and sustainability, environmental pollution, food production, clean energy, low-carbon transport promotion, and strategic governance for sustainable initiatives. This book can reveal facts about the challenges we are facing on the one hand and provide a better understanding of drivers, barriers, and motivations to achieve a better and more sustainable future for all on the other. Research presented in this volume can provide different stakeholders, including planners and policy makers, with better solutions for the implementation of SDGs. Prof. Bao-Jie He acknowledges the Project NO. 2021CDJQY-004 supported by the Fundamental Research Funds for the Central Universities. We appreciate the assistance from Mr. Lifeng Xiong, Mr. Wei Wang, Ms. Xueke Chen and Ms. Anxian Chen at School of Architecture and Urban Planning, Chongqing University, China
Railway bridge condition monitoring and fault diagnostics
The European transportation network is ageing continuously due to environmental threats, such as traffic, wind and temperature changes. Bridges are vital assets of the transportation network, and consequently their safety and availability need to be guaranteed to provide a safe transportation network to passenger and freights traffic. The main objective of this thesis is to develop a bridge condition monitoring and damage diagnostics method. The main element of the proposed Structural Health Monitoring (SHM) method is to monitor and assess the health state of a bridge continuously, by taking account of the health state of each element of the bridge. In this way, an early detection of the ongoing degradation of the bridge can be achieved, and a fast and cost-effective recovery of the optimal health state of the infrastructure can be achieved.
A BBN-based approach for bridge condition monitoring and damage diagnostics is proposed and developed to assess and update the health state of the bridge continuously, by taking account of the health state of each element of the bridge. At the same time, the proposed BBN approach allows to detect and diagnose damage of the bridge infrastructure.
Firstly, the BBN method is developed for monitoring the condition of two bridges, which are modelled via two Finite Element Models (FEMs). The Conditional Probability Tables (CPTs) of the BBN are defined by using an expert knowledge elicitation process. Results shows that the BBN allows to detect and diagnose damage of the bridges, however the performance of the BBN can be improved by pre-processing the data of the bridge behaviour and improving the definition of the CPTs.
A data analysis methodology is then proposed to pre-process the data of the bridge behaviour, and to use the results of the analysis as an input to the BBN. The proposed data analysis methodology relies on a five-step process: i) remove of the outlier of the bridge data; ii) identify of the free-vibration of the bridge; iii) extract statistical, frequency-based and vibration -based features from the free-vibration behaviour of the bridge; iv) assess the features trend over time, by using the extracted features as an input to an Empirical Mode Decomposition (EMD) algorithm; v) evaluate of the Health Indicator (HI) of the bridge element. The proposed data analysis methodology is tested on two in-field bridges, a steel truss bridge and a post-tensioned concrete bridge, which are subject to a progressive damage test.
A machine learning method is also developed in order to assess the health state of the bridge automatically. A Neuro Fuzzy Classifier (NFC) is adopted for this purpose. The results of the NFC can potentially be used as an input to the BBN nodes, to select the states of the BBN nodes, and improve the BBN performance. In fact, the NFC shows high accuracy in assessing the health state of bridge elements. An optimal set of HIs, which allows to maximize the accuracy of the NFC, is identified by adopting an iterative Modified Binary Differential Evolution (MBDE) method. The NFC is applied to the post-tensioned concrete in-field bridge that is subject to a progressive damage test.
Hence, the performance of the BBN is improved significantly by pre-processing the bridge data, but also by developing a novel method to continuously update the CPTs of the BBN. The CPTs update process relies on the actual health state of the bridge element, and the knowledge of bridge engineers. Indeed, the CPT updating method aims to merge the expert knowledge with the analysis of the bridge behaviour. In this way, the diagnostic ability of the BBN is improved by merging the expertise of bridge engineer, who can analyse hypothetical damage scenarios of the bridge, and the analysis of a database of known bridge behaviour in different health states. The method is verified on the post-tensioned concrete in-field bridge, by developing a BBN to monitor the health state of the bridge continuously. The damages of the bridge are diagnosed by the proposed BBN.
Finally, a method to analyse database of unknown infrastructure behaviour is finally proposed. An ensemble-based change-point detection method is presented to analyse a database of past unknown infrastructure behaviour. The method aims to identify the most critical change of the health state of the infrastructure, by providing the characteristics of such a change, in terms of time duration and possible causes. The method is applied to a database of tunnel behaviour, which is subject to renewal activities that influence the health state of the infrastructure
Railway bridge condition monitoring and fault diagnostics
The European transportation network is ageing continuously due to environmental threats, such as traffic, wind and temperature changes. Bridges are vital assets of the transportation network, and consequently their safety and availability need to be guaranteed to provide a safe transportation network to passenger and freights traffic. The main objective of this thesis is to develop a bridge condition monitoring and damage diagnostics method. The main element of the proposed Structural Health Monitoring (SHM) method is to monitor and assess the health state of a bridge continuously, by taking account of the health state of each element of the bridge. In this way, an early detection of the ongoing degradation of the bridge can be achieved, and a fast and cost-effective recovery of the optimal health state of the infrastructure can be achieved.
A BBN-based approach for bridge condition monitoring and damage diagnostics is proposed and developed to assess and update the health state of the bridge continuously, by taking account of the health state of each element of the bridge. At the same time, the proposed BBN approach allows to detect and diagnose damage of the bridge infrastructure.
Firstly, the BBN method is developed for monitoring the condition of two bridges, which are modelled via two Finite Element Models (FEMs). The Conditional Probability Tables (CPTs) of the BBN are defined by using an expert knowledge elicitation process. Results shows that the BBN allows to detect and diagnose damage of the bridges, however the performance of the BBN can be improved by pre-processing the data of the bridge behaviour and improving the definition of the CPTs.
A data analysis methodology is then proposed to pre-process the data of the bridge behaviour, and to use the results of the analysis as an input to the BBN. The proposed data analysis methodology relies on a five-step process: i) remove of the outlier of the bridge data; ii) identify of the free-vibration of the bridge; iii) extract statistical, frequency-based and vibration -based features from the free-vibration behaviour of the bridge; iv) assess the features trend over time, by using the extracted features as an input to an Empirical Mode Decomposition (EMD) algorithm; v) evaluate of the Health Indicator (HI) of the bridge element. The proposed data analysis methodology is tested on two in-field bridges, a steel truss bridge and a post-tensioned concrete bridge, which are subject to a progressive damage test.
A machine learning method is also developed in order to assess the health state of the bridge automatically. A Neuro Fuzzy Classifier (NFC) is adopted for this purpose. The results of the NFC can potentially be used as an input to the BBN nodes, to select the states of the BBN nodes, and improve the BBN performance. In fact, the NFC shows high accuracy in assessing the health state of bridge elements. An optimal set of HIs, which allows to maximize the accuracy of the NFC, is identified by adopting an iterative Modified Binary Differential Evolution (MBDE) method. The NFC is applied to the post-tensioned concrete in-field bridge that is subject to a progressive damage test.
Hence, the performance of the BBN is improved significantly by pre-processing the bridge data, but also by developing a novel method to continuously update the CPTs of the BBN. The CPTs update process relies on the actual health state of the bridge element, and the knowledge of bridge engineers. Indeed, the CPT updating method aims to merge the expert knowledge with the analysis of the bridge behaviour. In this way, the diagnostic ability of the BBN is improved by merging the expertise of bridge engineer, who can analyse hypothetical damage scenarios of the bridge, and the analysis of a database of known bridge behaviour in different health states. The method is verified on the post-tensioned concrete in-field bridge, by developing a BBN to monitor the health state of the bridge continuously. The damages of the bridge are diagnosed by the proposed BBN.
Finally, a method to analyse database of unknown infrastructure behaviour is finally proposed. An ensemble-based change-point detection method is presented to analyse a database of past unknown infrastructure behaviour. The method aims to identify the most critical change of the health state of the infrastructure, by providing the characteristics of such a change, in terms of time duration and possible causes. The method is applied to a database of tunnel behaviour, which is subject to renewal activities that influence the health state of the infrastructure
Pseudo National Security System of Health in Indonesia
ABstRACt Adolescence is a crucial period where one tends to identify who they are as an individual. However, as a teenager is struggling to find his/her place in this world, it is also a time where they are prone to engaging in risk behaviors, which tend to have an extreme psychological impact. The objective was to explore the experiences of an adolescent who engages in risk behaviors and to understand their level of personal fables. The study was a qualitative design with content analysis with semi-structured interviews of ten male adolescents aged 16-18 years. The major findings of the study indicated that adolescent’s pattern of thinking revolves around the fact that they are invincible and invulnerable. Furthermore, adolescents are aware of the risks they are putting themselves through and how in the process they are hurting others. The implications of the study are to conduct more life skill programs in schools; greater awareness has to be created on the impact and harmful effects of such behaviors
Assessing physical fitness and physical activity in population-based surveys
Edited by Thomas F. Drury.Includes bibliographical references and index.National Center for Health Statistics. Assessing Physical Fitness and Physical Activity in Population-Based Surveys. Thomas F. Drury, ed. DHHS pub. No, (PHS) 89-1253. Public Health Service. Washington. U.S. Government Printing Office. 1989Part I. Historical Perspectives -- 1. General Population Surveys of the National Center for Health Statistics: An Overview / Nancy D. Pearce -- 2. Cardiovascular Endurance, Strength, and Lung Function Tests in the National Health and Nutrition Examination Surveys / Arthur J. McDowell -- 3. Assessments of Body Composition, Dietary Patterns, and Nutritional Status in the National Health Examination Surveys and National Health and Nutrition Examination Surveys / Dorothy Blair,Jean-Pierre Habicht,andLeeAlekel -- -- Part II. Fundamental Perspectives on Health-Related Physical Fitness and Cardiopulmonary -- Health -- 4. Design Issues and Alternatives in Assessing Physical Fitness Among Apparently Healthy Adults in a Health Examination Survey of the General Population / Jack H. Wilmore -- 5. An Integrative Approach to the Noninvasive Assessment of Cardiovascular and Respiratory Function During Exercise / Karlman Wasserman -- -- Part III. Fundamental Perspectives on Energy Balance, Dietary Patterns, and Physical Activity -- 6. General Considerations Related to Assessing Energy Turnover: Energy Intake or Energy Expenditure / E. R. Buskirk -- 7. Issues Related to Measuring Energy Balance for the National Health and Nutrition Examination Survey / Dorothy Blair -- 8. Measuring Dietary Patterns in Surveys of Physical Fitness and Activity / Catherine E. Woteki -- 9. Design Issues and Alternatives in Assessing Physical Activity in General Population Surveys / Thomas Stephens -- -- Part IV. Special Subpopulation Issues -- 10. Fitness and Activity Assessment of Children and Adolescents / Oded Bar-Or -- 11, Evaluating Fitness and Activity Assessments From the National Children and Youth Fitness Studies I and II / James G. Ross -- 12. Assessing Fitness and Activity Patterns of Women in General Population Studies / Barbara L. Drinkwater -- 13. Exercise Testing and Physical Activity Assessment of Persons with Selected Cardiac Conditions / Nanette Kass Wenger -- 14. Health-Related Fitness of the Older Adult / Everett L. Smith and Catherine Gilligan -- -- Part V. Lessons From Community, National, and International Studies -- 15. Lessons from Tecumseh on the Assessment of Physical Activity and Fitness / Henry J. Montoye -- 16. Fitness and Activity Assessments Among U.S.Army Populations: Implications for NCHS General Population Surveys / James A. Vogel -- 17. Fitness and Activity Measurement in the 1981 Canada Fitness Survey / Thomas Stephens and Cora Lynn Craig -- 18. An International Perspective on Critical Issues in Fitness Testing of U.S. Adults / Roy J. Shephard -- -- Part VI. Contexts of Evaluation -- 19. Genetic Considerations in Physical Fitness / Robert M. Malina and Claude Bouchard -- 20. Biochemical Correlates of Fitness and Exercise / William L. Haskell -- 21. Evaluating the Health Effects of Demanding Work on and off the Job / James S. House and David A. Stiti -- 22. Effects of Physical Activity and Fitness on Health / Arthur S. Leon -- 23. Measurement and Evaluation of Health Behaviors in Relationship to Physical Fitness and Physical Activity Patterns / Steven N. Blair and Harold W. Kohl -- 24. Evaluating Interrelationships Among Physical Fitness and Activity Assessments / Ronald E. LaPorte -- 25. Cardiovascular Epidemiological Research Uses of Fitness Assessments / Erika S. Sivarajan and Victor F. Froelicher -- 26. Epidemiologic Uses of General Population Assessments of Physical Activity Patterns / Robert T. Hyde and Ralph S. Paffenbarger, Jr. -- -- Part VII. Measurement and Analysis Strategies -- 27. Use of Latent VariableModels in Measuring Physical Fitness and Physical Activity / George W. Bohrnstedt and Joseph Lucke -- 28. Applying Regression and Factor Analysis of Categorical Variables to Fitness and Exercise Data / Bengt Muthen and Lynn Short -- 29. Latent Class Analysis / Allan L. McCutcheon -- -- Appendix. Framingham Leisure Time Physical Activity Questionnaire / Andrew L. Dannenberg and Peter W. F. Wilson1989833