• Journal of the Ergonomics Society of Korea
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• v.29 no.4
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• pp.611-617
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• 2010

To find out why elderly drivers have more frequent traffic accidents on intersection than any other one, this study was conducted to examine the characteristics of elderly drivers' driving behavior on intersection using a multifaceted driving behavior indicator. To do that, the driving behavior of both young adult drivers and elderly drivers were compared and analyzed, using a graphic driving simulator. As a result, compared with young adult drivers, elderly drivers showed a poor driving performance, and a high ratio of visual scanning time on the specific direction regardless of driving situation. Also, compared with young adult drivers, elderly drivers had a high overall level of arousal, and the phasic arousal activity on the specific stimulus was low. These results imply that through the intervention which induces the change in multifaceted indicators mentioned earlier, they could be helped to drive more safely on intersection.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.5
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• pp.124-133
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• 2014

This study aims to track pedestrian behavior in urban linear tourist sites and to analyse their behavioral characteristics. For these purposes, this study has adopted the direct observation, a behavioral tracking methodology, and selected Chenggyecheon in Seoul as the study site, a representative site of urban regeneration. The main results of this study can be summarized as follows: the period of stay and movement distance of pedestrians in the study area are both short and most pedestrian activities, apart from walking, are of a passive nature, such as pitching pennies, reading signs, resting and the like. Spatial points of Chenggyecheon at which pedestrians have exhibited these behaviors during their stay are summarized as 30 points and classified into 3 types: landmarks, bridges and nodes. Further research that combines several tracking methods in terms of urban pedestrian behavior is needed.

• The Journal of Engineering Geology
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• v.30 no.2
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• pp.131-145
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• 2020

The construction on these flimsy ground, activation of unsymmetrical surcharges, can often cause of the embankment road lateral flow or the destruction of the activities. In this study, the stability of the abutment pile foundation installed on soft ground and its behavior has been evaluated. The behavior of the abutment pile foundation under lateral flow was studied by verifying the behavior and reinforcement effects of the abutment pile foundation of previous studies about horizontal loads acting on the pile due to the lateral flow of the ground by performing finite element analysis. As a result of the consolidation analyses, the undrained cohesion or the strength of the soft ground, was increased by about 1.1 to 1.8 times by the increase in the strength of the soft ground according to the degree of consolidation. It is deemed reasonable to use 3.8 cm of the allowable displacement both economically and constructively, but considering the importance of the structure and the uncertainty of the ground, measurement shall be carried out during construction and thorough safety management of the lateral flow should be done.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.2
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• pp.174-184
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• 1998

In order to accumulate fundamental. data for control of fishes’ behavior at the real fishing ground, the fitness of the numerical model for describing the behavior of fishes was examined by the marine fish. Mullet, Mugil cephalus were used as experimental fishes. The numerical model of fishes’ behavior presented in our earlier paper was modified on the vertical movement of fish school. For the comparision of parameters of the modified numerical model between mullet and rainbow trout, the estimated values of parameters were identified with dimension. The fitness of the modified numerical model was examined by the comparision between experiment and simulation on the several indexes represented by fishes’ swimming characteristics. The obtained result are summarized a follows : 1. The non-dimensional parameter a’ of propulsive force and kb’ of interactive force by the experiment without model net showed a similarity, but the non-dimensional parameter k sub(c’) of schooling force for rainbow trout was lager than one for mullet and the non-dimensional parameter k sub(w’) of repulsive force for mullet was lager than one for rainbow trout. 2. The non-dimensional parameter a’ and k sub(b’) for rainbow trout by the experiment with model net were a little lager than ones for mullet, but non-dimensional parameter k sub(c’) and k sub(w’) for mullet were lager than ones for rainbow trout. 3. The non-dimensional parameter k sub(c’) and k sub(b’) showed the largest and the smallest value among the non-dimensional parameters for rainbow trout and mullet, respectively. 4. The fitness of the modified numerical model was confirmed by means of the compulsion between experiment and simulation on the swimming trajectory of fishes, the mean distance of individual from wall, the mean swimming speed, the mean swimming depth and the mean distance between the nearest individuals. Especially, the similarity of mean swimming depth was improved by using the modified numerical model.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.2
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• pp.83-93
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• 2020

In fisheries, the importance of designing efficient fish cages is being emphasized as aquaculture has become more production than capture fishing. Particularly, the gravity cage system is one of the popular fish cage system in Korea. Currently, gravity cages of various shapes and sizes are being widely designed and installed in offshore and inland seas. The cage is subject to external forces, such as currents and waves, and the shape of the structure and tension on the ropes changes according to these external forces. Thus, it is important to accurately calculate these dynamic behavior, including the external forces and tension on the structure during the design stage. In this study, three types of cage systems with an equal internal volume of 8000 ㎥ were analyzed using mass-spring models and their behavior was interpreted through simulations. These simulations were used to analyze the behavior and tension of the ropes in response to currents and waves to aid in the selection of individual cage sizes for a given total volume. The numerical calculation results indicate that depending on the flow rate, the most resistant system is System 1, which has eight strays, and System 2 and System 3 have 69.4% and 54.8% of the resistance of System 1. Further, total resistance increased as the number of cages increased for all flow rates.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.1
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• pp.1-11
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• 2020

Behaviors of wake vortices generated by an aircraft affect the performance and flight stability of flying aircraft in formation flight. In the present study, the trajectories of the wake vortices behind airplanes in close formation flight were computed using a Fourier spectral method. The behavior of wake vortices showed complex patterns depending on the initial circulation and the relative positions between the vortices. In the initial stage, the wake vortex movement was affected by the nascent vortex. When the vortex becomes closer to the other vortex, then a new trajectory is formed. When the viscous effect becomes dominant, the core radius increases. Thus, a new vortex moving near the existing vortex can have strong interaction with each other, resulting in the complicated behavior of wake vortices. In the future, the ground effect on the behavior of the wake vortices during take-off and landing will be studied.

• The Journal of Internal Korean Medicine
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• v.43 no.3
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• pp.436-443
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• 2022

Objectives: This study examined the case of a 69-year-old man with a history of stroke and Alzheimer's disease who had been diagnosed with probable-rapid eye movement sleep behavior disorder (probable-RBD). Methods: The patient was treated with herbal medicine (Ukgan-san, Ukgansangayonggolmoryeo-tang, and powdered Gamisoyo-san extract), Western medicine (clonazepam, antiplatelet, psychotropic agents, antihypertensive drugs, and others), and acupuncture. Their effects were evaluated by the frequency and severity of sleep-related behavioral symptoms. Results: After treatment, the observed frequency and severity of sleep-related behavior decreased. Conclusion: The results suggest that using traditional Korean medicine with clonazepam can be effective in the treatment of patients with probable-RBD.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.2
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• pp.207-218
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• 2023

Jeju Island is a major area generates origin-destination trips, accounting for about 90 % of domestic air transportation, and popular tourist destination visited by more than 10 million domestic and foreign tourists annually. Travel behavior patterns of tourists in Jeju Island have great meaning for not only Jeju Island, but also the inland aviation, tourism, mobility industry. This study presented passenger travel behavior in Jeju Island based on a survey including foreign visitors and residents as well as domestic visitors. In particular, the survey was conducted in early 2020 prior to the COVID-19 pandemic, it is expected to be a major preliminary study for changes in tourist travel and air travel in Jeju Island before and after COVID-19.

• Steel and Composite Structures
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• v.49 no.4
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• pp.381-392
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• 2023

This study experimentally investigates the flexural behavior of steel-UHPC composite slabs composed of an innovative negative Poisson's ratio (NPR) steel plate and Ultra High Performance Concrete (UHPC) slab connected via demountable high-strength bolt shear connectors. Eight demountable composite slab specimens were fabricated and tested under traditional four-point bending method. The effects of loading histories (positive and negative bending moment), types of steel plate (NPR steel plate and Q355 steel plate) and spacings of high-strength bolts (150 mm, 200 mm and 250 mm) on the flexural behavior of demountable composite slab, including failure mode, load-deflection curve, interface relative slip, crack width and sectional strain distribution, were evaluated. The results revealed that under positive bending moment, the failure mode of composite slabs employing NPR steel plate was distinct from that with Q355 steel plate, which exhibited that part of high-strength bolts was cut off, part of pre-embedded padded extension nuts was pulled out, and UHPC collapsed due to instantaneous instability and etc. Besides, under the same spacing of high-strength bolts, NPR steel plate availably delayed and restrained the relative slip between steel plate and UHPC plate, thus significantly enhanced the cooperative deformation capacity, flexural stiffness and load capacity for composite slabs further. While under negative bending moment, NPR steel plate effectively improved the flexural capacity and deformation characteristics of composite slabs, but it has no obvious effect on the initial flexural stiffness of composite slabs. Meanwhile, the excellent crack-width control ability for UHPC endowed composite members with better durability. Furthermore, according to the sectional strain distribution analysis, due to the negative Poisson's ratio effect and high yield strength of NPR steel plate, the tensile strain between NPR steel plate and UHPC layer held strain compatibility during the whole loading process, and the magnitude of upward movement for sectional plastic neutral axis could be ignored with the increase of positive bending moment.

• Membrane Journal
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• v.28 no.1
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• pp.67-74
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• 2018

In the molecular dynamics study of polymeric membranes, it is very important to select the proper length of the polymer main chain because it requires a large number of constituent atoms and a long time to simulate the permeation behavior. In this study, we tried to investigate how the correlation between polymer main chain length and permeation behavior appears in actual molecular dynamics simulation results. Molecular dynamics were performed using the widely known commercial polymer Kapton(R) polyimide structure and the gas permeation behavior was simulated. The movement of the polymer main chain was not related to its length and the short main chain length did not act more actively. In addition, unlike the prediction that the end group of the polymer main chain is relatively easy to move, there are many cases where the atoms located at the middle of the polymer main chains have a higher movement than the atoms located at the end groups. Finally, permeabilities of the gas molecules was not affected by the length of the main chain and the end groups of the polymer, which indicates that the end effect should be carefully mentioned and followed by the verification process.