• Smart Structures and Systems
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• v.21 no.5
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• pp.687-694
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• 2018

The problem of wheel tread defects has become a major challenge for the health management of high-speed rail as a wheel defect with small radius deviation may suffice to give rise to severe damage on both the train bogie components and the track structure when a train runs at high speeds. It is thus highly desirable to detect the defects soon after their occurrences and then conduct wheel turning for the defective wheelsets. Online wheel condition monitoring using wheel impact load detector (WILD) can be an effective solution, since it can assess the wheel condition and detect potential defects during train passage. This study aims to develop an FBG-based track-side wheel condition monitoring method for the detection of wheel tread defects. The track-side sensing system uses two FBG strain gauge arrays mounted on the rail foot, measuring the dynamic strains of the paired rails excited by passing wheelsets. Each FBG array has a length of about 3 m, slightly longer than the wheel circumference to ensure a full coverage for the detection of any potential defect on the tread. A defect detection algorithm is developed for using the online-monitored rail responses to identify the potential wheel tread defects. This algorithm consists of three steps: 1) strain data pre-processing by using a data smoothing technique to remove the trends; 2) diagnosis of novel responses by outlier analysis for the normalized data; and 3) local defect identification by a refined analysis on the novel responses extracted in Step 2. To verify the proposed method, a field test was conducted using a test train incorporating defective wheels. The train ran at different speeds on an instrumented track with the purpose of wheel condition monitoring. By using the proposed method to process the monitoring data, all the defects were identified and the results agreed well with those from the static inspection of the wheelsets in the depot. A comparison is also drawn for the detection accuracy under different running speeds of the test train, and the results show that the proposed method can achieve a satisfactory accuracy in wheel defect detection when the train runs at a speed higher than 30 kph. Some minor defects with a depth of 0.05 mm~0.06 mm are also successfully detected.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.800-808
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• 2022

The International Maritime Organization adopted the interim standards for ship maneuverability in November 1993 for preventing collision of ships at sea and for protecting the marine environment, and based on the accumulated data, in December 2002, the established standards for ship maneuverability were adopted. However, the standards adopted are those at full load, even keel, and at least 90 % of the ship speed at 85 % of the ship's maximum power. Moreover, these standards have limitations in providing information on maneuverability under actual navigational conditions. Therefore, in this study, frequency analysis AHP analysis techniques were studied by consulting navigational officers, captains, and experts, who have significant knowledge on ship maneuverability, utilization of the current standards, and the information necessary for the operation of the actual ship. The results of this study confirmed that the necessary information on maneuverability for the navigational officer operating the vessel is information about the turning circle at a small angle of 5°-10° and z-test information at maneuvering speed, not sea speed. Additionally, in relation to speed control, additional information on deceleration inertia and acceleration inertia is needed than the information on the stopping ability at sea speed and full loaded condition. The derived results are considered to be useful as basic data for preparing guidelines for ship maneuverability necessary for navigational of icers who operate ships.

• Women's Health Nursing
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• v.9 no.3
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• pp.319-326
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• 2003

Objectives : A Pregnancy becomes a developmental challenge and a life-turning point for both the woman herself and her family. The purpose of this study was to identify the correlation amomg the family support, intention of pregnancy and the antenatal self-care of pregnant women. Method : The data were collected from 129 pregnant women by a questionnaire. The collected data were analyzed by descriptive statistics, t-test, ANOVA, Pearson's correlation coefficients, using the SPSS program. Result : The findings of the study are as fellows : Statistically significant variables related to family support were age, religion, educational level, occupation, relationship with husband, relationship with mother. Statistically significant variables related to intention of pregnancy were religion, abortion history. Statistically significant variables related to antenatal self-care were age, religion, occupation, abortion history, relationship with mother, the term of marriage. There was a significant correlation between family support and intention of pregnancy, family support and antenatal self-care, intention of pregnancy and antenatal self-care. Conclusion : Therefore, it is proposed that family support is an appropriate nursing intervention to improve the antenatal self-care and intention of pregnancy in pregnant women.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1858-1864
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• 2009

In this paper, we design a non-volatile memory IP, 1-kb one-time programmable (OTP) memory, used for power management ICs. Since a conventional OTP cell uses an isolated NMOS transistor as an antifuse, there is an advantage of it big cell size with the BCD process. We use, therefore, a PMOS transistor as an antifuse in lieu of the isolated NMOS transistor and minimize the cell size by optimizing the size of a OTP cell transistor. And we add an ESD protection circuit to the OTP core circuit to prevent an arbitrary cell from being programmed by a high voltage between the terminals of the PMOS antifuse when the ESD test is done. Furthermore, we propose a method of turning on a PMOS pull-up transistor of high impedance to eliminate a gate coupling noise in reading a non-programmed cell. The layout size of the designed 1-kb PMOS-type antifuse OTP IP with Dongbu's $0.18{\mu}m$ BCD is $129.93{\times}452.26{\mu}m^2$.

• Korean Journal of Applied Biomechanics
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• v.27 no.3
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• pp.157-164
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• 2017

Objective: The purpose of this study was to investigate kinematic differences in back pike somersault in platform diving according to skill level and to apply the findings to improve performance. Method: Korean divers participating in this study were divided into a skilled group (age: $21.6{\pm}4.16y$, height: $1.68{\pm}0.03m$, weight: $62.0{\pm}3.94kg$, career: $12.6{\pm}5.13y$) and a less-skilled group (age: $20.6{\pm}2.7y$, height: $1.72{\pm}0.05m$, weight: $64.8{\pm}6.76kg$, career: $12.2{\pm}2.49y$) and an independent t-test was performed to analyze differences between groups at the moment of takeoff. Results: The two groups showed significant differences in displacement and velocity of center of mass (COM), takeoff angle, hip joint angle, knee joint angular velocity, and hip joint angular velocity at the takeoff (p<.05), and significant differences in displacement of COM, hip joint, and ankle joint during flight (p<.05). Conclusion: For a successful back pike, the COM should rise quickly in the vertical direction and the hip joint angle and angular velocity should increase. To improve performance, the back pike turn should be practiced on the ground before an attempt on a 10-m platform, to stretch the ankle and knee joints and enable quick flexion of the hip joint when turning in flight.

• International Journal of Highway Engineering
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• v.17 no.4
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• pp.89-98
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• 2015

PURPOSES : This study evaluated the feasibility of implementing protected-permissive left-turn (PPLT) signals at three-leg signalized intersections. METHODS: A three-leg signalized intersection with permissive left-turn was first selected. A VISSIM simulation model was constructed using data collected from the test site. The VISSIM network was calibrated by adjusting related parameter values in order to minimize the difference between the simulated and surveyed critical gap. The calibrated network was validated by the number of waiting left-turning vehicles per cycle. Finally, the mobility and safety measures were extracted from simulation runs in which permissive, protected left turns as well as PPLTs were realized based on diverse traffic volume scenarios. RESULTS : The mobility-related measures of effectiveness (MOEs) of the case with PPLT outperformed the other two left-turn treatment scenarios. In particular, the average waiting time per cycle for the left-turn vehicles in the case with PPLT was reduced by 30 s. The safety-related MOEs of the case with PPLT were somewhat higher than those in the case with protected left-turns and much higher than those in the case with permissive left-turns. CONCLUSIONS : Based on the mobility- and safety-related MOEs generated from the VISSIM simulation runs, the use of PPLT seems to be feasible at three-leg signalized intersections where the left-turn is permissive and a pedestrian signal exists at the conflicting approach. However, in order to use the PPLT in earnest, it is necessary to revise the road traffic act, traffic signs, and related manuals.

• Journal of Physiology & Pathology in Korean Medicine
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• v.33 no.6
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• pp.363-369
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• 2019

This paper aims to assess the effect of herbal extract mixture, Ahn Tonic, on hair growth and examine the stability of this percutaneous hair growth ointment. The hair on the back of the mice C57b1/6N was removed, and 1% of the TXN(testosterone) was then applied for a week to prevent the hair growth. The experimental group was then treated with Ahn Tonic, 0.2 mL per day. The degree of newly grown hair was observed with a vernier caliper. We also measured the proportion of the newly growing hair section to the entire shaved section in the 4th week and 8th week by distinguishing the section turning black from the shaved area. To observe the effect of the test chemical product on hair follicles and hair roots, the biopsy was executed between week 4 and week 8. Gene expressions, which operate as a factor for growing hair in the skin tissues extracted from each experimental animals, were also observed through a real-time PCR gene amplification method. The results showed that the Ahn tonic group had statistically significant hair restoring effect compared to the control group in terms of microscopy, biopsy, and gene expressions. Ahn Tonic is considered to have an impact on the hair growth.

• Journal of Korean Society of Transportation
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• v.26 no.1
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• pp.145-153
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• 2008

Existing shortest-path algorithms mainly consider a single attribute. But traveler actually chooses a route considering not single attribute but various attributes which are synthesized travel time, route length, personal preference, etc. Therefore, to search the optimal path, these attributes are considered synthetically. In this study route searching algorithm which selects the maximum utility route using discrete choice model has developed in order to consider various attributes. Six elements which affect route choice are chosen for the route choice model and parameters of the models are estimated using survey data. A multinomial logit models are developed to design the function of route choice model. As a result, the model which has route length, delay time, the number of turning as parameter is selected based on the significance test. We use existing shortest path algorithm, which can reflect urban transportation network such as u-turn or p-turn, and apply it to the real network.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.98-99
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• 2016

The aim of study is to develop a dual driven ship berthing/deberthing system with $360^{\circ}$ steerability. A large ship used bow thruster, side thruster and pod propulsor etc. when approaching to a pier. But as marine leisure boats become large-scaled, the number of accidents is recently increasing what caused a ship to crash into a ship and a ship to crash into mooring facilities during berthing/deberthing on a marina. To solve the problem, the control responsiveness of a joystick connected with two motors and a propeller was checked and torque was increased by the electromagnetic design of magnetic gear. A sea trial test was carried out to investigate a performance of the developed system in the real sea.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.4
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• pp.9-17
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• 2019

PURPOSE: This research was designed to study the correlations between physical activities such as foot sensory impairment, balance and ambulatory abilities, as well as fall risk factors and mental activities such as cognitive performance and depression in order to provide fundamental data for the prevention of falling in the elderly. METHODS: A total of 36 elderly people over the age of 65 years who voluntarily joined the research were selected as subjects. Sensory perception in both feet was measured by using a monofilament in 10 parts with each part given one point. The points for each foot were integrated to analyze the correlations between physical and mental activities indices, and the results were analyzed by using Pearson's correlation coefficient. RESULTS: The results of this research show that the extent to which senses in feet were impaired was correlated to TUG, a functional activity index involved in tranfers, gait, and turning movements, which was correlated to BBS (balance index) as well as MMSE-K and K-GDS (mental activities index). BBS was interrelated to FES-K (physical activities index) and MMSE-K. The muscular strength of the right ankle dorsiflexor had mutual relations with FES-K. CONCLUSION: The results of this research indicate that TUG is widely correlated to foot sensory impairment as well as general physical and mental activities in elderly people. BBS was also shown to be correlated with TUG, FES-K, and MMSE-K. Thus, it might be necessary that TUG and BBS be included as two items in physical and mental check-ups for the elderly, and further studies on correlations using evaluation items for physical and mental activities should lead to the simplification of the evaluation criteria.