• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.20 no.1
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• pp.16-28
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• 2015

In order to elucidate the spatiotemporal variations of marine environmental parameters, we collected seawater samples in the south-western region of the East Sea in May, August, and November 2012 and February 2013. The concentrations of dissolved inorganic nutrients (dissolved inorganic nitrogen, phosphorus, and silicate) in surface seawater during the summer season were lower than those during autumn and winter seasons, which the mixed layer is deeper. The low nutrient concentration in spring and summer seasons seems by consumption of dissolved inorganic nutrients by phytoplankon photosynthesis (high chlorophyll a concentration) and the limited supply of dissolved inorganic nutrients from subsurface layer having high nutrients. The low nutrient concentration during spring season seems to be related to the limited supply of dissolved inorganic nutrients from land and subsurface layer because the concentration of chlorophyll a was low. The DIN:DIP ratio was a wide range of average $15.6{\pm}13.6$ in the surface seawater compared to that of average $14.8{\pm}4.2$ in the bottom seawater during sampling periods. The dissolved inorganic nitrogen might act as a limiting factor of the growth of phytoplankton because the DIN:DIP ratio (on average $8.35{\pm}4.67$) was low during the spring season.

• The Journal of Internal Korean Medicine
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• v.40 no.4
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• pp.730-741
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• 2019

Objective: The aim of this study was to report the effectiveness of traditional Korean medicine treatment with rehabilitation exercise on a chronic intracerebral hemorrhage patient with a severe gait disturbance. Method: The patient was treated with Korean herbal medicine (Gami-sibjeondaebo-tang) along with acupuncture, moxibustion, and rehabilitation exercise. The treatment effect was evaluated through the Manual Muscle Test (MMT) and the Korean version of the Modified Barthel Index (K-MBI). The gait of the patient was evaluated by Functional Ambulatory Category (FAC) and the Timed Up and Go (TUG) test. The spatiotemporal parameters were evaluated by a walkway system (GAITRite(R) system) and gait symmetry was evaluated by Symmetry Criterion (SC). Results: After 111 days of traditional Korean medicine treatment, the spatiotemporal parameters and symmetry of the patient's gait improved. Conclusion: This study suggested that traditional Korean medicine treatment with rehabilitation exercise could be effective for gait disturbance in patients with chronic intracerebral hemorrhage.

• Journal of the Korean Society of Physical Medicine
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• v.10 no.4
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• pp.25-31
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• 2015

PURPOSE: Previous studies have shown that healthy young adults reduced gait velocity during texting or talking while walking. It was reported that increasing number of pedestrian accidents were related to distract the environmental attention. The purpose of this study was to compare the effects of texting and texting while listening to music on gait parameters. METHODS: Texting and listening to music while walking were assessed in two dual-task condition using 35 healthy young adults. The outcome measurements were assessed in terms of spatiotemporal gait parameters in three walking conditions, namely, comfortable walking speed, walking while texting, and walking while texting and listening to music. To avoid learning effect, subjects were individually blinded to assessment schedule and space. The changes between the three walking conditions were analyzed using repeated measures ANOVA. RESULTS: When comparing the two dual-task conditions with the single-task condition, it was found that dual-task interference was increased in almost gait velocity, cadence, stride length, step time, double limb support, and single limb support. In addition, walking while texting and listening to music condition negatively was affected gait speed, stride length, and step time more than the texting only condition. CONCLUSION: Walking while texting and listening to music as well as waling while texting may decrease pedestrian safety when crossing streets by diverting the person's attention away from the street environment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.10
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• pp.3858-3874
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• 2021

As an essential part of the urban transportation system, precise perception of the traffic flow parameters at the traffic signal intersection ensures traffic safety and fully improves the intersection's capacity. Traditional detection methods of road traffic flow parameter can be divided into the micro and the macro. The microscopic detection methods include geomagnetic induction coil technology, aerial detection technology based on the unmanned aerial vehicles (UAV) and camera video detection technology based on the fixed scene. The macroscopic detection methods include floating car data analysis technology. All the above methods have their advantages and disadvantages. Recently, indoor location methods based on wireless signals have attracted wide attention due to their applicability and low cost. This paper extends the wireless signal indoor location method to the outdoor intersection scene for traffic flow parameter estimation. In this paper, the detection scene is constructed at the intersection based on the received signal strength indication (RSSI) ranging technology extracted from the wireless signal. We extracted the RSSI data from the wireless signals sent to the road side unit (RSU) by the vehicle nodes, calibrated the RSSI ranging model, and finally obtained the traffic flow parameters of the intersection entrance road. We measured the average speed of traffic flow through multiple simulation experiments, the trajectory of traffic flow, and the spatiotemporal map at a single intersection inlet. Finally, we obtained the queue length of the inlet lane at the intersection. The simulation results of the experiment show that the RSSI ranging positioning method based on wireless signals can accurately estimate the traffic flow parameters at the intersection, which also provides a foundation for accurately estimating the traffic flow state in the future era of the Internet of Vehicles.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.6
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• pp.2450-2469
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• 2018

In this paper, we develop a spatiotemporal model to analysis of cellular user in underlay D2D communication by using stochastic geometry and queuing theory. Firstly, by exploring stochastic geometry to model the user locations, we derive the probability that the SINR of cellular user in a predefined interval, which constrains the corresponding transmission rate of cellular user. Secondly, in contrast to the previous studies with full traffic models, we employ queueing theory to evaluate the performance parameters of dynamic traffic model and formulate the cellular user transmission mechanism as a M/G/1 queuing model. In the derivation, Embedded Markov chain is introduced to depict the stationary distribution of cellular user queue status. Thirdly, the expressions of performance metrics in terms of mean queue length, mean throughput, mean delay and mean dropping probability are obtained, respectively. Simulation results show the validity and rationality of the theoretical analysis under different channel conditions.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.1
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• pp.1-9
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• 2020

PURPOSE: Many patients with stroke have difficulties in walking with foot-drop. Various types of ankle-foot orthoses (AFOs) have been developed, but their weight needs to be reduced with the assistance of the ankle dorsiflexor. Therefore, an elastic AFO (E-AFO) was devised that not only improves the stability and flexibility of the ankle but also assists with ankle dorsiflexion while walking. This study examined the effects of an E-AFO, on the walking patterns of foot-drop patients with stroke. METHODS: Fourteen patients walked with and without an E-AFO, and the gait parameters were assessed using the GAITRite system. The spatiotemporal data on the gait patterns of stroke patients with foot-drop were compared using paired t-tests; the level of statistical significance was set to α<.05. RESULTS: No significant differences were observed in the velocity (p=.066) and affecte+d step length (p=.980), but the affected and less-affected stance (p=.022, p=.002) and swing time (p=.012, p=.005) were significantly different. The E-AFO produced a significant difference in the less-affected step length (p=.032). CONCLUSION: The E-AFO has a significant effect on the walking patterns of individuals with foot-drop and stroke. The E-AFO could be a useful assistive device for gait training in stroke patients.

• Korean Journal of Remote Sensing
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• v.36 no.4
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• pp.609-626
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• 2020

Satellite-based land surface temperature (LST) has been used as one of the major parameters in various climate and environmental models. Especially, Moderate Resolution Imaging Spectroradiometer (MODIS) LST is the most widely used satellite-based LST product due to its spatiotemporal coverage (1 km spatial and sub-daily temporal resolutions) and longevity (> 20 years). However, there is an increasing demand for LST products with finer spatial resolution (e.g., 10-250 m) over regions such as urban areas. Therefore, various methods have been proposed to produce high-resolution MODIS-like LST less than 250 m (e.g., 100 m). The purpose of this review is to provide a comprehensive overview of recent research trends and challenges for the downscaling of MODIS LST. Based on the recent literature survey for the past decade, the downscaling techniques classified into three groups-kernel-driven, fusion-based, and the combination of kernel-driven and fusion-based methods-were reviewed with their pros and cons. Then, five open issues and challenges were discussed: uncertainty in LST retrievals, low thermal contrast, the nonlinearity of LST temporal change, cloud contamination, and model generalization. Future research directions of LST downscaling were finally provided.

• The Journal of Korean Physical Therapy
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• v.33 no.1
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• pp.34-39
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• 2021

Purpose: The purpose of this study was to verify the effectiveness of repetitive sit to stand training to improve knee extensor strength and walking ability of total knee replacement patients. Methods: In this study, 12 patients with total knee replacement patients were recruited from a rehabilitation hospital. They were divided into two groups: a repetitive sit to stand group (n=6) and a control group (n=6). They all received 30 minutes of continuous passive motion (CPM). After that, the repetitive sit to stand group performed repetitive sit to stand training, and the control group performed resistance exercise for 15 minutes five times a week for 2 weeks. After 2 weeks of training, knee extensor strength and spatiotemporal gait parameters were measured. Knee extensor strength was measured by Biodex system 3, walking ability was measured by Biodex gait trainer 2. Paired t test was performed to verify the difference between before and after intervention within the group, and analysis of covariance was used to verify the differences between the two groups. Results: After the training periods, the repetitive sit to stand group showed a significant improvement in knee extensor muscle strength, walking speed, step length of the operated side, and step length of the non-operated side (p<0.05). Conclusion: The results of this study showed that repetitive sit to stand training was more effective in improving knee extensor muscle strength and walking ability. Therefore, to strengthen knee extensor muscles and improve the walking ability of total knee replacement patients, it is necessary to consider repetitive sit to stand training.

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3653-3664
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• 2021

In PWR three-dimensional transient coupling calculation software CORCA-K, the nodal Green's function method and diagonal implicit Runge Kutta method are used to solve the spatiotemporal neutron dynamic diffusion equation, and the single-phase closed channel model and one-dimensional cylindrical heat conduction transient model are used to calculate the coolant temperature and fuel temperature. The LMW, NEACRP and PWR MOX/UO₂ benchmarks and FangJiaShan (FJS) nuclear power plant (NPP) transient control rod move cases are used to verify the CORCA-K. The effects of burnup, fuel effective temperature and ejection rate on the control rod ejection process of PWR are analyzed. The conclusions are as follows: (1) core relative power and fuel Doppler temperature are in good agreement with the results of benchmark and ADPRES, and the deviation between with the reference results is within 3.0% in LMW and NEACRP benchmarks; 2) the variation trend of FJS NPP core transient parameters is consistent with the results of SMART and ADPRES. And the core relative power is in better agreement with the SMART when weighting coefficient is 0.7. Compared with SMART, the maximum deviation is -5.08% in the rod ejection condition and while -5.09% in the control rod complex movement condition.

• Physical Therapy Rehabilitation Science
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• v.6 no.3
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• pp.106-112
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• 2017

Objective: Robot assisted gait training is implemented as part of therapy for the recovery of gait patterns in recent clinical fields, and the scope of implications are continuously increasing. However clear therapy protocols of robot assisted gait training are insufficent. The purpose of this study was to investigate the effects of robot-assisted gait training applied with guidance force on balance and gait performance in persons with hemiparetic stroke. Design: Two group pre-test post-test design. Methods: Nineteen persons were diagnosed with hemiparesis following stroke participated in this study. The participants were randomly assigned to the unilateral guidance group or bilateral guidance group to conduct robot-assisted gait training. All participants underwent robot-assisted gait training for twelve sessions (30 min/d, 3 d/wk for 4 weeks). They were assessed with gait parameters (gait velocity, cadence, step length, stance phase, and swing phase) using Optogait. This study also measured the dynamic gait index (DGI), the Berg balance scale (BBS) score, and timed up and go (TUG). Results: After training, BBS scores were was significantly increased in the bilateral training group than in the unilateral guidance group (p<0.05). Spatiotemporal parameters were significantly changed in the bilateral training group (gait speed, swing phase ratio, and stance phase ratio) compared to the unilateral training group (p<0.05). Conclusions: The results of this study suggest that robot-assisted gait training show feasibility in facilitating improvements in balance and gait performance for subacute hemiparetic stroke patients.