• Journal of the Korean Society for Precision Engineering
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• v.20 no.3
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• pp.194-201
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• 2003

This study presents the comparative filtration performance evaluation of automotive fuel filters based on the theory of Beta ratio. For the experiments, the fuel component's test stand incorporating the multi-pass filtration test circuit was developed. A mathematical description of filtration process in general was derived. And the theoretical basis of multi-pass test and the test procedure were described in detail. Experimental results revealed that domestic fuel filter tested could not maintain consistent Beta ratio, that is filtration efficiency, although it had the holding capacity of contaminants close to the specification at maximum pressure drop across the filter assembly. The results of experiments and simulations also showed that filtration system model could be refined including desorption ratio to estimate the variable Beta ratio in service life.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.4
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• pp.35-41
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• 2007

The most agricultural concrete structures for the irrigation and drainage are exposed to the underwater condition at the irrigation period and they take the influence on very severe cold in the winter. Therefore, it is impossible to use repair materials used to the general concrete structures. The research need the development of the repair material for a performance enhance of the agricultural underwater concrete structures. This research evaluated the mechanical and durability performance of the latex modified repair mortar for underwater concrete structures which peformed the repair in the underwater according to the characteristic of the agricultural concrete structure. The latex modified repair mortar is a material that minimize the effect of the ecosystem, environment and the segregation. In this research, the construction condition of the latex modified repair mortar for agricultural concrete structures was considered and the test specimens made in the underwater condition. Test results was then compared with target performance and commercial repair mortar. Experimental test results indicated that the mechanical and durability performance of latex modified repair mortar for agricultural underwater concrete structure satisfied all target performance. Also, the latex modified repair mortar resulted in better repair performance than the commercial repair mortar.

• Journal of Ocean Engineering and Technology
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• v.33 no.4
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• pp.330-339
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• 2019

Radiant heat shields are normally installed on offshore oil and gas platforms to protect personnel, equipment, and structures from the thermal radiation emitted by a flare system. A heat shield should be individually designed to reduce the thermal radiation to the target level, and then manufactured and installed after the performance verification. However, in general, a heat shield is designed and manufactured by trial and error based on the performance test. For this reason, it is difficult to develop and design radiant heat shields in the Korean shipbuilding and marine equipment industry because of the lack of performance test data and limited experience. In the present study, the results of experiments conducted to verify the performances of radiant heat shields were analyzed, and the thermal radiation characteristics and performance characteristics of the radiant heat shields were investigated. The insights and conclusions developed in the present study will be useful in terms of the design and development of radiant heat shield, as well as in their performance verification tests.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.15-19
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• 2001

Electronic navigation system onboard have have been developed with recent technology based on new concept such as electronic chart date. The most valuable system of revolution in electronic navigation equipment is ECDIS, which have been developed in order to reduce work load of mariner and give an integrated information by simple means, especially to improve the safety of ship's navigation. In order to be sure the function of ECDIS is satisfied, The international standard have regulated the performance in the standard, so ECDIS should be type approved by the marine equipment authority of each government. There are three basic documents, IEC61174, IEC61162, IEC60945 issued by IMO(International Maritime Organization) which should be used for type approval system of each authority. IEC 61174 include the method of test and required results for operational and functional performance of test equipment. IEC61162 is for sensor interface and IEC60945 is related to the test of environmental condition for general marine radiocommunication equipment. In this paper, we investigate international standard in detail and current approval system of general marine equipment. After that, we present the possible structure of type approval of ECDIS and important considerations of approval system such that ECDIS should be tested as one system not be separated between S/W and H/W.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.2 s.95
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• pp.176-183
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• 2005

The exhaust noise of auxiliary engine in ships is directly transmitted to bridge wing with only distance attenuation. It is not easy to find out practical treatment to be applied between exhaust pipe and bridge wing to reduce the transmission of the exhaust noise. In general, therefore, a silencer is fitted to reduce the exhaust noise and correspondingly noise of bridge wing. The silencer should be properly designed under the consideration of the frequency component of the exhaust noise and the required performance such as noise reduction or insertion loss. In general, the gas inside the exhaust pipe flows with high temperature and speed and thus onboard test condition is more adverse than the standard atmospheric condition. In this study, the test method to evaluate silencer performance using a probe microphone is introduced.

• Journal of Audiology & Otology
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• v.24 no.3
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• pp.133-139
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• 2020

Background and Objectives: The Gaps-In-Noise (GIN) test is a clinically effective measure of the integrity of the central auditory nervous system. The GIN procedure can be applied to a pediatric population above 7 years of age. The present study conducted the GIN test to compare the abilities of auditory temporal resolution among typically developing children, children with speech sound disorder (SSD), and children with cognitive difficulty (CD). Subjects and Methods: Children aged 8 to 11 years-(total n=30) participated in this study. There were 10 children in each of the following three groups: typically developing children, children with SSD, and children with CD. The Urimal Test of Articulation and Phonology was conducted as a clinical assessment of the children's articulation and phonology. The Korean version of the Wechsler Intelligence Scale for Children-III (K-WISC-III) was administered as a screening test for general cognitive function. According to the procedure of Musiek, the pre-recorded stimuli of the GIN test were presented at 50 dB SL. The results were scored by the approximated threshold and the overall percent correct score (%). Results: All the typically developing children had normal auditory temporal resolution based on the clinical cutoff criteria of the GIN test. The children with SSD or CD had significantly reduced gap detection performance compared to age-matched typically developing children. The children's intelligence score measured by the K-WISC-III test explained 37% of the variance in the percent-correct score. Conclusions: Children with SSD or CD exhibited poorer ability to resolve rapid temporal acoustic cues over time compared to the age-matched typically developing children. The ability to detect a brief temporal gap embedded in a stimulus may be related to the general cognitive ability or phonological processing.

• Korean Journal of Audiology
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• v.24 no.3
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• pp.133-139
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• 2020

Background and Objectives: The Gaps-In-Noise (GIN) test is a clinically effective measure of the integrity of the central auditory nervous system. The GIN procedure can be applied to a pediatric population above 7 years of age. The present study conducted the GIN test to compare the abilities of auditory temporal resolution among typically developing children, children with speech sound disorder (SSD), and children with cognitive difficulty (CD). Subjects and Methods: Children aged 8 to 11 years-(total n=30) participated in this study. There were 10 children in each of the following three groups: typically developing children, children with SSD, and children with CD. The Urimal Test of Articulation and Phonology was conducted as a clinical assessment of the children's articulation and phonology. The Korean version of the Wechsler Intelligence Scale for Children-III (K-WISC-III) was administered as a screening test for general cognitive function. According to the procedure of Musiek, the pre-recorded stimuli of the GIN test were presented at 50 dB SL. The results were scored by the approximated threshold and the overall percent correct score (%). Results: All the typically developing children had normal auditory temporal resolution based on the clinical cutoff criteria of the GIN test. The children with SSD or CD had significantly reduced gap detection performance compared to age-matched typically developing children. The children's intelligence score measured by the K-WISC-III test explained 37% of the variance in the percent-correct score. Conclusions: Children with SSD or CD exhibited poorer ability to resolve rapid temporal acoustic cues over time compared to the age-matched typically developing children. The ability to detect a brief temporal gap embedded in a stimulus may be related to the general cognitive ability or phonological processing.

• The Journal of Korean Society for School & Community Health Education
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• v.13 no.1
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• pp.77-87
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• 2012

This study is a descriptive paper addressing the relationship between test anxiety, self-esteem and the mental health levels of freshmen and third year students of Dental Hygienics. In late 2011, we received a total of 298 questionnaires from freshmen and third year Dental Hygienics students of three South Korean universities, located specifically in Seoul and Gyeonggi-do. The timing of this questionnaire was significant because it was one week prior to midterm examinations. The results were as follows:1. There was a statistically significant relationship between age (t=3.017, p<.001) and grade(t=2.665, p<0.05), subjective health status(t=27.513, p<.001). 2. The lower the participants' reported mental health in general, the higher their level of test anxiety (r=.565, p<.001), broken down into two subdivisions: cognitive text anxiety (r=526, p<.001) and emotional test anxiety (r=.534, p<.001). 3. When considering the factors that influence the general mental health of participants, there were age differences. For first year students, their subjeetive health status (${\ss}$=-.300, p<.001) and test anxiety (${\ss}$=.530, p<.001) were significant. For third year students, this was also true (subjective mental condition: ${\ss}$=-.242, p<.001 and test anxiety: ${\ss}$=.350, p<.001) but self-worth was also significant (${\ss}$=.377, p<.001). The results of this study suggest that the key factors that influence the mental health level of students Dental Hygienics are test anxiety, subjective appraisal of health level, and general self-worth. A systematic approach is therefore needed to improve students' mental health and reduce test anxiety. Health management programs which address and test students' physical health will also be important in improving student performance and welfare.

• The Korean Journal of Emergency Medical Services
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• v.20 no.3
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• pp.69-83
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• 2016

Purpose: The purpose of this study was to explore the factors influencing evidence-based fall prevention nursing performance of hospital nurses. Methods: A self-reported questionnaire was completed by 344 nurses from three general hospitals from January 20 to March 10, 2013. The study instruments included general characteristics of the subjects, and awareness and performance of fall prevention. Data were analyzed by t test, ANOVA, Pearson's correlation, and multiple regression using SPSS v. 20.0. Results: There were statistically significant differences in awareness and performance according to age, marital status, clinical experiences, workplace, experience of fall prevention education, knowledge of fall prevention, compliance with fall prevention, attention level toward prevention, recognition level of potential falls, nurse responsibility for falls, importance of fall prevention, efforts level for fall prevention, and awareness score of falls prevention. There was a positive correlation among awareness and performance of fall prevention. Based on the multiple regression analysis, compliance with fall prevention, efforts level for fall prevention, and awareness score of falls prevention were significant predictors for performance of fall prevention. The explanation power of the model was 64.1%. Conclusion: The findings revealed the need to develop an effective nursing intervention to improve hospital nurses' performance for fall prevention.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.9
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• pp.818-826
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• 2002

Since multipath phenomenon frequently occurs when a Global Positioning System receiver is placed in urban area crowded with large buildings, efficient mitigation of multipath effects is necessary to resolve. In this paper, we propose a new multipath detection technique that is useful in real-time positioning with a general Global Positioning System receiver. The proposed technique is based on a channelwise multipath test statistic that efficiently indicates the degree of fluctuations induced by multipath error. The proposed multipath test statistic is operationally advantageous because it does not require any specialized hardware nor any pre-computation of receiver position, it is directly related to standard $\chi$$^2$-distributions, and it can adjust the detection resolution by increasing the number of successive measurements. Simulation and experiment results verify the performance of the proposed multipath detection technique.