Spatiotemporal Characteristics of Neural Dynamics in Theta Oscillations Related to the Inhibition of Habitual Behavior

The human brain carries out cognitive control for the inhibition of habitual behaviors by suppressing some familiar but inappropriate behaviors instead of engaging specific goal-directed behavior flexibly in a given situation. To examine the characteristics of neural dynamics related to such inhibition of habitual behaviors, we used a modified rock-paper-scissors (RPS) task that consisted of a basic, a lose-, and a win-conditioned game. Spectral and phase synchrony analyses were conducted to examine the acquired electroencephalogram signals across the entire brain during all RPS tasks. Temporal variations in frontal theta power activities were directly in line with the stream of RPS procedures in accordance with the task conditions. The lose-conditioned RPS task gave rise to increases in the local frontal power and global phase-synchronized pairs of theta oscillations. The activation of the global phase-synchronized network preceded the activation of frontal theta power. These results demonstrate that the frontal regions play a pivotal role in the inhibition of habitual behaviors-stereotyped and ingrained stimulus-response mappings that have been established over time. This study suggests that frontal theta oscillations may be engaged during the cognitive inhibition of habitual behaviors and that these oscillations characterize the degree of cognitive load required to inhibit habitual behaviors

Analysis of stress distribution in piezoelectric MEMS energy harvester using shaped cantilever structure

Much interest in energy harvesters has been focused on maintaining their conversion efficiency during scaling down via the micromachining process. The piezoelectric PZTbased MEMS energy harvester was designed and fabricated to increase the fraction of the material strained during deflection since the geometric change of the cantilever shape can change the strain distribution on the beam and improve the output power. The generated power during beam deflection was separately collected from individual electrodes located at different positions of the cantilever, and they had good agreement with the strain estimation from finite element analysis. The trapezoidal shape showed 39% higher power than that of rectangular one.OAIID:RECH_ACHV_DSTSH_NO:T200700101RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A080442CITE_RATE:.512DEPT_NM:조경·지역시스템공학부SCOPUS_YN:YCONFIRM:

Structural Behaviors of Reinforced Concrete Piers Rehabilitated with FRP Wraps

The use of fiber-reinforced polymer (FRP) wraps to retrofit and strengthen existing structures such as reinforced concrete piers is becoming popular due to the higher tensile strength, durability, and flexibility gained and the method’s ease of handling and low installation and maintenance costs. As yet, however, few guidelines have been developed for determining the optimum thicknesses of the FRP wraps applied to external surfaces of concrete or masonry structures. In this study, nonlinear pushover finite element analyses were utilized to analyze the complex structural behaviors of FRP-wrapped reinforced rectangular piers. Design parameters such as pier section sizes, pier heights, pier cap lengths, compressive strengths of concrete, and the thicknesses of the FRP wraps used were thoroughly tested under incremental lateral and vertical loads. The results provide useful guidelines for analyzing and designing appropriate FRP wraps for existing concrete piers

Three-Dimensional Finite Element Analyses for Buried Concrete Pipes in the Imperfect Trench Installations

The objective of this study was to validate the superiority of the induced (or imperfect) trench installations (ITI) with proposed soft material zone for buried concrete pipes using 3D FE analyses and nonlinear soil models. The ITI method is used to reduce earth pressure on deeply buried conduits. There, however, have been limited research results published regarding primarily qualitative aspects of earth load reduction for imperfect trench conditions. Kang et al. proposed the optimum geometry of the soft material zone using 2D finite element (FE) models. Their studies, however, had several limitations: 1) plane strain approach only; and 2) no available field test data for the modeling validation at that point. The developed 3D FE models have been validated and calibrated using experimental field studies from Valsangkar et al., and showed good agreements with the experimental studies. The limitations of the previous 2D FE models by Kang et al. have successfully been overcome by this study. The findings and recommendations presented in this report, therefore, would provide the detailed guidelines for envisioned field studies and ITI design. It is hoped that an innovative understanding of the soil-structure interaction for deeply buried conduits and other findings presented in this study will find their way into improved specifications in the near future. As the economic impact appears to be huge, immediate implementation of these findings by designers and contractors is particularly urgent for conduits buried under several hundred feet of fill

Structural Behaviors of Reinforced Concrete Piers Rehabilitated with FRP Wraps

The use of fiber-reinforced polymer (FRP) wraps to retrofit and strengthen existing structures such as reinforced concrete piers is becoming popular due to the higher tensile strength, durability, and flexibility gained and the method’s ease of handling and low installation and maintenance costs. As yet, however, few guidelines have been developed for determining the optimum thicknesses of the FRP wraps applied to external surfaces of concrete or masonry structures. In this study, nonlinear pushover finite element analyses were utilized to analyze the complex structural behaviors of FRP-wrapped reinforced rectangular piers. Design parameters such as pier section sizes, pier heights, pier cap lengths, compressive strengths of concrete, and the thicknesses of the FRP wraps used were thoroughly tested under incremental lateral and vertical loads. The results provide useful guidelines for analyzing and designing appropriate FRP wraps for existing concrete piers

Composite and non-composite behaviors of foam insulated concrete sandwich panels

The structural behaviors of foam-insulated concrete sandwich panels subjected to uniform pressure have been evaluated. This study showed that the interface conditions such as composite and non-composite had a significant effect on the response of foam-insulated concrete sandwich panels, indicating that the simulated shear tie resistance should indeed be incorporated in numerical analyses. Finite element models were developed to simulate the detailed shear resistance of connectors and the nonlinear behaviors of concrete, foam and rebar components. The models were then validated using data from static tests performed at the University of Missouri. The modeling approach used here was compatible with the American Concrete Institute (ACI) Code and existing design practices. The results of this study will therefore provide improved methodology for the analysis and design of foam-insulated sandwich panels under both static and blast loadings.The work reported herein was partially supported by Auburn University and Georgia Southern University. The investigator is grateful for their sponsorship. This study does not necessarily reflect the opinions or conclusions of Auburn University or Georgia Southern University.OAIID:RECH_ACHV_DSTSH_NO:T200700112RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A080442CITE_RATE:3.85DEPT_NM:조경·지역시스템공학부SCOPUS_YN:YCONFIRM:

GIS Based Assessment and Design for Areas Vulnerable to Soil Disasters: Case Study of Namhyeun-dong, South Korea

Due to climate change, heavy rainfall events that trigger landslips are becoming common. This study investigates patterns in the soil’s response to major rainfall events in mountainous areas and proposes a new approach for resilient disaster prevention technology and recovery based on the effect of soil runoff. Namhyeon-dong within Seoul was selected for the case study because of its vulnerable location between two mountains. A master plan was developed to cope with the predicted soil runoff based on the annual rainfall, local land use and a series of 10-year forecasts covering the period from 2021 to 2100. A total of 22 catchments in the study area were analyzed with Arc Hydro, an ArcGIS plug-in and appropriate technologies proposed to deal with the soil runoff likely to be experienced in each catchment in an extreme disaster. The resulting model was deemed adequate to deal with disasters during the period predicted to represent the highest risk, 2051–2060. The study’s findings will help to forecast disasters from flood that could impact residential areas in mountainous regions, to predict the magnitude of potential soil disasters in individual regions and develop design guidelines for disaster prevention technology based on the predicted amount of soil runoff

Analysis of Flood Damage in the Seoul Metropolitan Government Using Climate Change Scenarios and Mitigation Technologies

The social and economic damages caused by climate change have increased rapidly over the last several decades, with increasing instances of heatwaves, floods, and extreme rainfall. In 2011, heavy rain of 110.5 mm/hr caused great damage to the Seoul Metropolitan Government. Most of the causes of flooding in modern cities include a sharp increase in non-permeable pavement and a lack of water circulation facilities. It is predicted that heavy rainfalls will occur in the future, causing large amounts of local damage. In this study, possible future flood damages were analyzed using climate change scenarios based on the Korean Peninsula. ArcGIS was adopted to perform analyses, and Huff curves were employed for precipitation analysis. Water tanks, permeable pavement, and ecological waterways were installed as mitigation technologies. These three technologies can contribute to flooding mitigation by increasing the rainwater storage capacity. This study suggests that all floods can be reduced by RCP 8.5 by 2050 and 2060. Although there will be run-off after 2050, it is believed that technology will significantly reduce the volume and possibility of floods. It is recommended that a one-year analysis should be conducted in consideration of the maintenance aspects that will arise in the future

AI based temperature reduction effect model of fog cooling for human thermal comfort: Climate adaptation technology

This study developed a gradient-boosted regression tree-based artificial intelligence (AI) model––temperature reduction effect AI model (TREAM)––to determine the temperature reduction effect of fog cooling that varies with weather conditions. According to the trend of global warming, our society is suffering from serious damage from urban heat islands, especially negatively affecting human health and thermal comfort. Therefore, it is very important to develop and evaluate adaptive technology for providing pleasant thermal comfort to humans. This study select fog cooling as adaptive technology for human thermal comfort, and indoor and outdoor simulation were performed using STAR CCM+, a computational fluid dynamics(CFD) program. Moreover, transient analysis to validate the outdoor model of CFD and parametric study to identify the correlation between the environmental factors and fog cooling were performed. When initial temperature set as 45 °C at a relative humidity of 90% and wind speed of 1 m/s, a temperature reduction of 8.92% can be obtained. Regardless of the temperature and humidity conditions, the temperature reduction effect of fog cooling was ∼1% if the wind speed increased above 5 m/s. This study contributed to the quantitative analysis of the temperature reduction effect according to the change of environmental factors. © 2023 The Author(s)N