The purpose of this study is to investigate the control function and mechanisms of natural river notches. Physical and numerical experiments are analyzed in this study for two representative types of sediment events：...The purpose of this study is to investigate the control function and mechanisms of natural river notches. Physical and numerical experiments are analyzed in this study for two representative types of sediment events： high intensity and short duration Type A sediment disaster events, and low intensity and long duration Type B moderate non-disaster events. Two dimensionless parameters, sediment trapping rate and reduction rate of peak sediment transport, are defined to evaluate the sediment control function of river notches. Study results indicate that the contraction ratio of the notch has a significant influence on sediment control function, with high contraction ratios resulting in both high sediment-trapping and high reduction rates. River notches provide better sediment control during Type A events than Type B events. The sediment control mechanism of river notches is the result of multiple interactions among river flow, sediment transport, and riverbed variation. Analysis of these interactions supports the significant protection role of river notches on sediment control for disaster events.展开更多
In real-life freeway transportation system, a few number of incident observation （very rare event） is available while there are large numbers of normal condition dataset. Most of researches on freeway incident detec...In real-life freeway transportation system, a few number of incident observation （very rare event） is available while there are large numbers of normal condition dataset. Most of researches on freeway incident detection have considered the incident detection problem as classification one. However, because of insufficiency of incident events, most of previous researches have utilized simulated incident events to develop freeway incident detection models. In order to overcome this drawback, this paper proposes a wavelet-based Hotelling 7a control chart for freeway incident detection, which integrates a wavelet transform into an abnormal detection method. Firstly, wavelet transform extracts useful features from noisy original traffic observations, leading to reduce the dimensionality of input vectors. Then, a Hotelling T2 control chart describes a decision boundary with only normal traffic observations with the selected features in the wavelet domain. Unlike the existing incident detection algorithms, which require lots of incident observations to construct incident detection models, the proposed approach can decide a decision boundary given only normal training observations. The proposed method is evaluated in comparison with California algorithm, Minnesota algorithm and conventional neural networks. The experimental results present that the proposed algorithm in this paper is a promising alternative for freeway automatic incident detections.展开更多
This paper will review three broad types of political implications of emergency management, since historically emergency management was considered only a function of law enforcement and fire departments, with the supp...This paper will review three broad types of political implications of emergency management, since historically emergency management was considered only a function of law enforcement and fire departments, with the support in the event of a major catastrophe from public health and civil defense organizations. The issue is not whether governments will be required to respond to emergencies but rather when and how frequently. The time to think about emergencies is before they happen. Despite some significant weakness in the overall approach, political implications offer many benefits and provide various options for CDCs （community development corporations） to get involved in disaster recovery and emergency management. Based upon a generally positive evaluation, the paper concludes that emergency management must become a central activity, whether at the federal, state, or local or as an intergovernmental activity. Hopefully for the future the government does not have to wait for a disaster to strike for one to put a policy into place, since they have had several to occur over decades. The government should be ready to take on any disaster if it occurs with the following policies and procedures that are in place.展开更多
基金financial support were provided by the Disaster Prevention Research Center, National Cheng Kung University
文摘The purpose of this study is to investigate the control function and mechanisms of natural river notches. Physical and numerical experiments are analyzed in this study for two representative types of sediment events： high intensity and short duration Type A sediment disaster events, and low intensity and long duration Type B moderate non-disaster events. Two dimensionless parameters, sediment trapping rate and reduction rate of peak sediment transport, are defined to evaluate the sediment control function of river notches. Study results indicate that the contraction ratio of the notch has a significant influence on sediment control function, with high contraction ratios resulting in both high sediment-trapping and high reduction rates. River notches provide better sediment control during Type A events than Type B events. The sediment control mechanism of river notches is the result of multiple interactions among river flow, sediment transport, and riverbed variation. Analysis of these interactions supports the significant protection role of river notches on sediment control for disaster events.
文摘In real-life freeway transportation system, a few number of incident observation （very rare event） is available while there are large numbers of normal condition dataset. Most of researches on freeway incident detection have considered the incident detection problem as classification one. However, because of insufficiency of incident events, most of previous researches have utilized simulated incident events to develop freeway incident detection models. In order to overcome this drawback, this paper proposes a wavelet-based Hotelling 7a control chart for freeway incident detection, which integrates a wavelet transform into an abnormal detection method. Firstly, wavelet transform extracts useful features from noisy original traffic observations, leading to reduce the dimensionality of input vectors. Then, a Hotelling T2 control chart describes a decision boundary with only normal traffic observations with the selected features in the wavelet domain. Unlike the existing incident detection algorithms, which require lots of incident observations to construct incident detection models, the proposed approach can decide a decision boundary given only normal training observations. The proposed method is evaluated in comparison with California algorithm, Minnesota algorithm and conventional neural networks. The experimental results present that the proposed algorithm in this paper is a promising alternative for freeway automatic incident detections.
文摘This paper will review three broad types of political implications of emergency management, since historically emergency management was considered only a function of law enforcement and fire departments, with the support in the event of a major catastrophe from public health and civil defense organizations. The issue is not whether governments will be required to respond to emergencies but rather when and how frequently. The time to think about emergencies is before they happen. Despite some significant weakness in the overall approach, political implications offer many benefits and provide various options for CDCs （community development corporations） to get involved in disaster recovery and emergency management. Based upon a generally positive evaluation, the paper concludes that emergency management must become a central activity, whether at the federal, state, or local or as an intergovernmental activity. Hopefully for the future the government does not have to wait for a disaster to strike for one to put a policy into place, since they have had several to occur over decades. The government should be ready to take on any disaster if it occurs with the following policies and procedures that are in place.
