• Journal of Korean Neurosurgical Society
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• v.54 no.6
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• pp.484-488
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• 2013

Objective : To examine the synergistic effects of both computer-assisted cognitive rehabilitation (CACR) and transcranial direct current stimulation (tDCS) on cognitive function in patients with stroke. Methods : The current double-blind, sham-controlled study enrolled a total of 11 patients who were newly diagnosed with stroke. The patients of the tDCS group (n=6) completed sessions of the Korean computer-assisted cognitive rehabilitation program five times a week for 30 minutes a session during a mean period of 18.5 days concomitantly with the anodal tDCS over the bilateral prefrontal cortex combined with the CACR. The patients of the control group (n=5) also completed sessions of the sham stimulation during a mean period of 17.8 days. Anodal tDCS over bilateral prefrontal cortex (F3 and F4 in 10-20 EEG system) was delivered for 30 minutes at an intensity of 2 mA. Cathode electrodes were applied to the non-dominant arm. All the patients were evaluated using the Seoul Computerized Neuropsychological Test (SCNT) and the Korean Mini-Mental State Examination. Results : Mann-Whitney U test revealed a significant difference between the two groups. The patients of the tDCS group achieved a significant improvement in the post/pre ratio of auditory continuous performance test and visual continuous performance test on the SCNT items. Conclusion : Our results indicate that the concomitant use of the tDCS with CACR to the prefrontal cortex may provide additional beneficial effects in improving the cognitive dysfunction for patients with stroke.

• Journal of Audiology & Otology
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• v.24 no.1
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• pp.10-16
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• 2020

Background and Objectives:The blockage of adenosine receptors by caffeine changes the levels of neurotransmitters. These receptors are present in all parts of the body, including the auditory and vestibular systems. This study aimed to evaluate the effect of caffeine on evoked potentials using auditory brainstem responses (ABRs) and cervical vestibular-evoked myogenic potentials (cVEMPs) in a double-blind placebo-controlled study. Subjects and Methods: Forty individuals (20 females and 20 males; aged 18-25 years) were randomly assigned to two groups: the test group (consuming 3 mg/kg pure caffeine powder with little sugar and dry milk in 100 mL of water), and the placebo group (consuming only sugar and dry milk in 100 mL water as placebo). The cVEMPs and ABRs were recorded before and after caffeine or placebo intake. Results: A significant difference was observed in the absolute latencies of I and III (p<0.010), and V (p<0.001) and in the inter-peak latencies of III-V and I-V (p<0.001) of ABRs wave. In contrast, no significant difference was found in cVEMP parameters (P13 and N23 latency, threshold, P13-N23 amplitude, and amplitude ratio). The mean amplitudes of P13-N23 showed an increase after caffeine ingestion. However, this was not significant compared with the placebo group (p>0.050). Conclusions: It seems that the extent of caffeine's effects varies for differently evoked potentials. Latency reduction in ABRs indicates that caffeine improves transmission in the central brain auditory pathways. However, different effects of caffeine on auditory- and vestibular-evoked potentials could be attributed to the differences in sensitivities of the ABR and cVEMP tests.

• Korean Journal of Audiology
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• v.24 no.1
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• pp.10-16
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• 2020

Background and Objectives:The blockage of adenosine receptors by caffeine changes the levels of neurotransmitters. These receptors are present in all parts of the body, including the auditory and vestibular systems. This study aimed to evaluate the effect of caffeine on evoked potentials using auditory brainstem responses (ABRs) and cervical vestibular-evoked myogenic potentials (cVEMPs) in a double-blind placebo-controlled study. Subjects and Methods: Forty individuals (20 females and 20 males; aged 18-25 years) were randomly assigned to two groups: the test group (consuming 3 mg/kg pure caffeine powder with little sugar and dry milk in 100 mL of water), and the placebo group (consuming only sugar and dry milk in 100 mL water as placebo). The cVEMPs and ABRs were recorded before and after caffeine or placebo intake. Results: A significant difference was observed in the absolute latencies of I and III (p<0.010), and V (p<0.001) and in the inter-peak latencies of III-V and I-V (p<0.001) of ABRs wave. In contrast, no significant difference was found in cVEMP parameters (P13 and N23 latency, threshold, P13-N23 amplitude, and amplitude ratio). The mean amplitudes of P13-N23 showed an increase after caffeine ingestion. However, this was not significant compared with the placebo group (p>0.050). Conclusions: It seems that the extent of caffeine's effects varies for differently evoked potentials. Latency reduction in ABRs indicates that caffeine improves transmission in the central brain auditory pathways. However, different effects of caffeine on auditory- and vestibular-evoked potentials could be attributed to the differences in sensitivities of the ABR and cVEMP tests.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.6
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• pp.52-61
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• 2015

Personal distance is one of the basic and important concepts in the field of Environmental Psychology in influencing personal space, visible or invisible territoriality and psychological carrying capacity of contemporary urban dwellers. This study aims to analyze the bench users' behaviour and personal distances in urban parks for the first time in Korea, one of the representative landscape spaces in urban areas. For these purposes, this study has adopted a blind observation and pictorial analysis for bench users in Yeouido Park in Seoul. The main results of this study show that the average interpersonal distance between female and male(intimate relationship) is 47.5cm, the distance between female and female is 53.2cm, and the distance between male and male is 70.3cm. These results mostly support the previous western study results, but the interpersonal space and territoriality of Koreans in urban parks may be smaller than that for western societies.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.8
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• pp.619-627
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• 2017

MIMO(Multi-Input Multi-Output) radar is an emerging radar technology for its numerous advantages. However, in the electric warfare viewpoint, MIMO radar is a new developed radar technology for that existing parameter estimation cannot applied and a new radar parameter estimation based on the characteristics of MIMO radar is desired. In this paper, we propose a blind estimation scheme for the number of orthogonal waveforms of a uniform linear array(ULA) MIMO radar using minimum two electronic sensors.

• Journal of Biosystems Engineering
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• v.34 no.4
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• pp.278-285
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• 2009

Navigation system is applied in variety of fields including the simple location positioning, autopilot navigation of unmanned robot tractor, autonomous guidance systems for agricultural vehicles, construction of large field works that require high precision and map making process. Particularly utilization of GPS (Global Positioning System) is very common in the present navigation system. This study introduces a navigation system for autonomous field robot that travels to the pre-input path using GPS information. Performance of the GPS- based navigation is highly depended on its receiving rate because GPS receivers do not acquire any navigation information in the period between the refresh intervals. So this study presents an algorithm that improves an accuracy of the navigation by estimation the positional information during the blind period of a low rate GPS receiver. In fact the algorithm calculated the robot's heading in a 50 Hz rate, so the blind period of an 1 Hz GPS receiver is extensively covered. Consequently implementation of the algorithm to the GPS based navigation showed an improvement in guidance accuracy. The conventional field robot directly carried an expensive control computer and sensors onboard, therefore the miniaturization and weight reduction of the robot was limited. In this paper, the field robot carried only communication equipments such as GPS module, normal RC receiver, and bluetooth modem. This enabled the field robot to be built in an economic cost and miniature size.

• Journal of Korea Multimedia Society
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• v.24 no.2
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• pp.267-273
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• 2021

Recently, the small-size mobile robots with remote-control are rapidly growth which market of mobile is increased in the world. Especially, the smart-phones are widely used for interface device in the small size of a mobile robot. The research goal is control system design which is applied to miniaturization of a mobile robot using smart-phone and it can be confirmed performance for designed system. Meanwhile, the fabrication of mini-mobile robot can also be remote-control operation through the WIFI performance of a smart-phone. The smart-phone is used to remote-control for robot operation which control data transmit to robot via the WIFI network. To drive the robot, we can observe by the smart-phone screen and it can easily adjust the robot drive condition and direction by smart-phone button. Consequentially, there was no malfunction and images were printed out well. However, in drive, because of blind spot, robot was bumped into obstacle. Therefore, the additional test is necessary to sensor for blind spot which sensor can be equipment to mobile robot. In addition, the experiment with robot object recognition is needed.

• Journal of Periodontal and Implant Science
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• v.46 no.1
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• pp.46-56
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• 2016

Purpose: We evaluated the efficacy of a mouthwash containing potassium nitrate ($KNO_3$) as its main component, along with sodium fluoride (NaF) and cetylpyridinium chloride (CPC). The primary endpoint was the relief of dentin hypersensitivity (DH) against the cold stimuli. The effects on other DH tests and periodontal inflammation were also evaluated. Methods: We used a single-center, double-blind, placebo-controlled, randomized design. A total of 82 patients with DH (40 in the test group, 42 placebo controls) were analyzed using visual analog scales (VASs) for a cold test, a tactile test, a compressive air test, and self-reported pain during daily activities, as well as clinical parameters including plaque index, gingival index, modified sulcular bleeding index (mSBI), gingival recession, and probing depth, which were collected at baseline and after four and six weeks of mouthwash use. Results: VAS scores for cold sensations, tactile sensations, the compressive air test, and self-reported pain significantly decreased from baseline during the six weeks in both groups (P<0.01), and no significant differences between the groups were found. In male patients (10 in the test group and 7 in the control group), both groups showed significant reductions in VAS scores for the cold test over the six weeks, and greater reductions were found in the test group than in the control group between four and six weeks (P=0.01) and between baseline and six weeks (P<0.01). In addition, the mSBI in the test group significantly decreased from baseline during the six weeks (P<0.01), and the changes at four and six weeks from baseline were significantly greater in the test group compared to the control group (P=0.03 and P=0.02, respectively). Conclusions: A mouthwash containing a mixture of $KNO_3$, NaF, and CPC reduced DH and gingival inflammation, however, the efficacy was comparable to the control group.

• Journal of Auto-vehicle Safety Association
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• v.5 no.1
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• pp.44-49
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• 2013

This paper presents a lateral collision risk index between an ego vehicle and a rear-side vehicle. The lateral collision risk is designed to represent a lateral collision risk and provide the appropriate threshold value of activation of the lateral collision management system such as the Blind Spot Detection(BSD). The lateral collision risk index is designed using the Time to Line Crossing(TLC) and the longitudinal collision index at the predicted TLC. TLC and the longitudinal collision index are calculated with the signals from the exterior sensor such as the radar equipped on the rear-side of a vehicle and a vision sensor which detects the distance and time to the lane departure. For the robust situation assessment, the perception of driving environment determining whether the road is straighten or curved should be determined. The relative motion estimation method has been proposed with the road information via the integrated estimator using the environment sensors and vehicle sensor. A lateral collision risk index was composed with the estimated relative motion considering the relative yaw angle. The performance of the proposed lateral collision risk index is investigated via computer simulations conducted using the vehicle dynamics software CARSIM and Matlab/Simulink.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.523-525
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• 2022

본 논문에서는 시각장애인을 위한 교통시설 앱 서비스를 제안한다. 이 서비스는 시각장애인이 편리하게 사용하고 안전하게 교통수단을 이용할 수 있는 음성지원 경로 알림이 탑재되어 있는 내비게이션 앱이다. 스마트 디바이스 기기만 있으면 쉽게 설치가 가능하며, 이를 통해 시각장애인에게 경로 이탈에 대한 두려움을 줄이고 음성지원 경로 알림 서비스를 제공해 안전하게 교통수단을 이용할 수 있다. 50개국 이상 언어지원 블록체인을 이용한 구조 A-GPS, T MAP, 음성을 사용 본 논문에서는 시뮬레이션을 통하여 문제점 해소와 더 나아가 시각장애인의 독립적인 이동 문화 형성을 제공한다.