The objective of this paper is to develop a framework to assess the potential risk for high ocean... more The objective of this paper is to develop a framework to assess the potential risk for high ocean waves detected by high frequency radar systems. High ocean waves due to earthquakes, strong wind, and/or other climate conditions have become one of the major natural hazards. Various coastal disasters including beach erosion along the shoreline are also caused by high waves. In order to decrease the damage caused by coastal disasters, it is essential to predict high ocean waves and assess their risk. Using the Bayesian approach, conditional probability of exceeding high ocean wave threshold is estimated with the predicted wave heights, which are calculated based on the measured data from high frequency radar systems. The data used is drawn from two Wellen radar systems that were installed in Samcheok City, Gangwon-do on the East Coast of South Korea. Additionally, Monte Carlo analysis is conducted to estimate conditional probability of exceeding the given threshold against coastal haza...
The rapid enhancement of central power unit CPU performance enables the development of computatio... more The rapid enhancement of central power unit CPU performance enables the development of computationally-intensive healthcare mobile applications for smartphones and wearable devices. However, computationally intensive mobile applications require significant application development time during the application porting procedure when the number of considering target devices operating systems OSs is large. In this paper, we propose a novel retargetable application development platform for healthcare mobile applications, which reduces application development time with maintaining the performance of the algorithm. Although the number of applications target OSs increases, the amount of time required for the code conversion step in the application porting procedure remains constant in the proposed retargetable platform. Experimental results show that our proposed retargetable platform gives reduced application development time compared to the conventional platform with maintaining the perfor...
This study presents a path planning method for a mobile robot to be effectively operated through ... more This study presents a path planning method for a mobile robot to be effectively operated through a multi-objective decision-making problem. Specifically, the proposed Fuzzy analytic hierarchy process (FAHP) determines an optimal position as a sub-goal within the multi-objective boundary. The key features of the proposed FAHP are evaluating the candidates according to the fuzzified relative importance among objectives to select an optimal solution. In order to incorporate FAHP into path planning, an AHP framework is defined, which includes the highest level (goal), middle level (objectives), and the lowest level (alternatives). The distance to the target, robot’s rotation, and safety against collision between obstacles are considered as objective functions. Comparative results obtained from the artificial potential field and AHP/FAHP simulations show that FAHP is much preferable for the mobile robot’s path planning than typical AHP.
The application of active structural control technology to highway bridge structures subjected to... more The application of active structural control technology to highway bridge structures subjected to high-impact loadings is investigated. The effects of high-impact loads on infrastructure, like heavy vehicle collisions with bridge piers, have not been studied as much as seismic load effects on structures. Due to this lack of research regarding impact loads and structural control, a focused study on the application of active control devices to infrastructure after impact events can provide valuable results and conclusions. This research applies active structural control to an idealized two-span, continuous girder, concrete highway bridge structure. The idealization of a highway bridge structure as a two degree-of-freedom structural system is used to investigate the effectiveness of control devices installed between the bridge pier and deck, the two degrees of freedom. The control devices are fixed to bracing between the bridge pier and girders and controlled by the proportional-integr...
This paper proposes a reliability analysis framework for glass fiber-reinforced polymer- (GFRP-) ... more This paper proposes a reliability analysis framework for glass fiber-reinforced polymer- (GFRP-) reinforced concrete systems with uncertain capacities and demands over time. Unfortunately, there has been limited discussion or research done related to the potential change of failure modes over time. Therefore, a rational approach is needed to integrate multiple failure modes in a single analysis framework, considering uncertainties of time-variant demands and capacities. To account for multiple failure modes, this study proposes the limit state function to estimate the safety margin, based on strain values of GFRP-reinforcing bars. A proposed limit state function can capture the likelihood of both shear and flexural failure modes, simultaneously. In this study, seven typical bridge deck configurations (e.g., varied deck thickness, girder spacing, and bar size) were exposed to various ambient temperatures. Simulation results show that reliability indices of 100-year exposure exhibit s...
Accurate heart rate detection is important in healthcare and exercise monitoring. Recently, heart... more Accurate heart rate detection is important in healthcare and exercise monitoring. Recently, heart rate monitoring using a smartphone has been highlighted due to its convenience and accuracy. In this paper, we hypothesize that our smartphone-based heart rate detection algorithm reliably detects heart rate based on fingertip image changes. Here, we have used successive video camera fingertip images with edge detection and smoothing techniques to process the fingertip images and to find out the heart rate of the subject. To investigate the capability of our proposed algorithm, we recruited 3 subjects and collected 2-min video data from each subject. We evaluated the performance of our proposed method by comparing it to the previous average intensity-based method [1]. Test results show that our proposed and previous methods give similar heart rate detection performance.
This chapter proposes a novel smart fuzzy control algorithm for mitigation of dynamic responses o... more This chapter proposes a novel smart fuzzy control algorithm for mitigation of dynamic responses of seismically excited bridge structures equipped with control devices. The smart fuzzy controller is developed through the combination of discrete wavelet transform, backpropagation neural networks, and Takagi-Sugeno fuzzy model. To demonstrate the effectiveness of the proposed smart fuzzy controller, it is tested on a highway bridge equipped with magneto rheological (MR) dampers. It controls the smart dampers installed on the abutments of the highway bridge structure. The 1940 El-Centro and Kobe earthquakes are used as disturbance signals. It is demonstrated that the smart fuzzy controller is effective in reducing the structural responses of the highway bridge under a variety of seismic excitations.
This paper proposes a multiclass nonlinear relevance vector machine (MNRVM) model for health moni... more This paper proposes a multiclass nonlinear relevance vector machine (MNRVM) model for health monitoring of smart structures equipped with magnetorheological (MR) dampers. The proposed model will be used to classify the damage statuses of the integrated structure-control systems subjected to ambient excitations. A numerical model of a three-story building equipped with an MR damper is studied to demonstrate the effectiveness of the proposed health monitoring schemes. Dynamic responses of the smart structures subjected to random excitations are measured. Discrete wavelet transform is applied to the obtained data to compress and filter noises of the measured data. As a next step, the compressed and de-noised signals are used for developing autoregressive (AR) models. Then the MNRVM is applied to the AR-coefficient data to classify them with respect to the damage statuses. As a baseline, the support vector machine (SVM) algorithm is considered. It is demonstrated that the proposed MNRVM framework is effective in classifying various damage statuses of the nonlinear smart structures subjected to ambient excitations. Simulation results also show that the MNRVM performs similar to the SVM with faster computation time.
The objective of this paper is to develop a framework to assess the potential risk for high ocean... more The objective of this paper is to develop a framework to assess the potential risk for high ocean waves detected by high frequency radar systems. High ocean waves due to earthquakes, strong wind, and/or other climate conditions have become one of the major natural hazards. Various coastal disasters including beach erosion along the shoreline are also caused by high waves. In order to decrease the damage caused by coastal disasters, it is essential to predict high ocean waves and assess their risk. Using the Bayesian approach, conditional probability of exceeding high ocean wave threshold is estimated with the predicted wave heights, which are calculated based on the measured data from high frequency radar systems. The data used is drawn from two Wellen radar systems that were installed in Samcheok City, Gangwon-do on the East Coast of South Korea. Additionally, Monte Carlo analysis is conducted to estimate conditional probability of exceeding the given threshold against coastal haza...
The rapid enhancement of central power unit CPU performance enables the development of computatio... more The rapid enhancement of central power unit CPU performance enables the development of computationally-intensive healthcare mobile applications for smartphones and wearable devices. However, computationally intensive mobile applications require significant application development time during the application porting procedure when the number of considering target devices operating systems OSs is large. In this paper, we propose a novel retargetable application development platform for healthcare mobile applications, which reduces application development time with maintaining the performance of the algorithm. Although the number of applications target OSs increases, the amount of time required for the code conversion step in the application porting procedure remains constant in the proposed retargetable platform. Experimental results show that our proposed retargetable platform gives reduced application development time compared to the conventional platform with maintaining the perfor...
This study presents a path planning method for a mobile robot to be effectively operated through ... more This study presents a path planning method for a mobile robot to be effectively operated through a multi-objective decision-making problem. Specifically, the proposed Fuzzy analytic hierarchy process (FAHP) determines an optimal position as a sub-goal within the multi-objective boundary. The key features of the proposed FAHP are evaluating the candidates according to the fuzzified relative importance among objectives to select an optimal solution. In order to incorporate FAHP into path planning, an AHP framework is defined, which includes the highest level (goal), middle level (objectives), and the lowest level (alternatives). The distance to the target, robot’s rotation, and safety against collision between obstacles are considered as objective functions. Comparative results obtained from the artificial potential field and AHP/FAHP simulations show that FAHP is much preferable for the mobile robot’s path planning than typical AHP.
The application of active structural control technology to highway bridge structures subjected to... more The application of active structural control technology to highway bridge structures subjected to high-impact loadings is investigated. The effects of high-impact loads on infrastructure, like heavy vehicle collisions with bridge piers, have not been studied as much as seismic load effects on structures. Due to this lack of research regarding impact loads and structural control, a focused study on the application of active control devices to infrastructure after impact events can provide valuable results and conclusions. This research applies active structural control to an idealized two-span, continuous girder, concrete highway bridge structure. The idealization of a highway bridge structure as a two degree-of-freedom structural system is used to investigate the effectiveness of control devices installed between the bridge pier and deck, the two degrees of freedom. The control devices are fixed to bracing between the bridge pier and girders and controlled by the proportional-integr...
This paper proposes a reliability analysis framework for glass fiber-reinforced polymer- (GFRP-) ... more This paper proposes a reliability analysis framework for glass fiber-reinforced polymer- (GFRP-) reinforced concrete systems with uncertain capacities and demands over time. Unfortunately, there has been limited discussion or research done related to the potential change of failure modes over time. Therefore, a rational approach is needed to integrate multiple failure modes in a single analysis framework, considering uncertainties of time-variant demands and capacities. To account for multiple failure modes, this study proposes the limit state function to estimate the safety margin, based on strain values of GFRP-reinforcing bars. A proposed limit state function can capture the likelihood of both shear and flexural failure modes, simultaneously. In this study, seven typical bridge deck configurations (e.g., varied deck thickness, girder spacing, and bar size) were exposed to various ambient temperatures. Simulation results show that reliability indices of 100-year exposure exhibit s...
Accurate heart rate detection is important in healthcare and exercise monitoring. Recently, heart... more Accurate heart rate detection is important in healthcare and exercise monitoring. Recently, heart rate monitoring using a smartphone has been highlighted due to its convenience and accuracy. In this paper, we hypothesize that our smartphone-based heart rate detection algorithm reliably detects heart rate based on fingertip image changes. Here, we have used successive video camera fingertip images with edge detection and smoothing techniques to process the fingertip images and to find out the heart rate of the subject. To investigate the capability of our proposed algorithm, we recruited 3 subjects and collected 2-min video data from each subject. We evaluated the performance of our proposed method by comparing it to the previous average intensity-based method [1]. Test results show that our proposed and previous methods give similar heart rate detection performance.
This chapter proposes a novel smart fuzzy control algorithm for mitigation of dynamic responses o... more This chapter proposes a novel smart fuzzy control algorithm for mitigation of dynamic responses of seismically excited bridge structures equipped with control devices. The smart fuzzy controller is developed through the combination of discrete wavelet transform, backpropagation neural networks, and Takagi-Sugeno fuzzy model. To demonstrate the effectiveness of the proposed smart fuzzy controller, it is tested on a highway bridge equipped with magneto rheological (MR) dampers. It controls the smart dampers installed on the abutments of the highway bridge structure. The 1940 El-Centro and Kobe earthquakes are used as disturbance signals. It is demonstrated that the smart fuzzy controller is effective in reducing the structural responses of the highway bridge under a variety of seismic excitations.
This paper proposes a multiclass nonlinear relevance vector machine (MNRVM) model for health moni... more This paper proposes a multiclass nonlinear relevance vector machine (MNRVM) model for health monitoring of smart structures equipped with magnetorheological (MR) dampers. The proposed model will be used to classify the damage statuses of the integrated structure-control systems subjected to ambient excitations. A numerical model of a three-story building equipped with an MR damper is studied to demonstrate the effectiveness of the proposed health monitoring schemes. Dynamic responses of the smart structures subjected to random excitations are measured. Discrete wavelet transform is applied to the obtained data to compress and filter noises of the measured data. As a next step, the compressed and de-noised signals are used for developing autoregressive (AR) models. Then the MNRVM is applied to the AR-coefficient data to classify them with respect to the damage statuses. As a baseline, the support vector machine (SVM) algorithm is considered. It is demonstrated that the proposed MNRVM framework is effective in classifying various damage statuses of the nonlinear smart structures subjected to ambient excitations. Simulation results also show that the MNRVM performs similar to the SVM with faster computation time.
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