• Journal of Korean Society of Transportation
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• v.35 no.4
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• pp.332-347
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• 2017

Analysis of the interaction between the automated vehicles and manual vehicles is very important in analyzing the performance of automated cooperative driving environments. In particular, the automated vehicle platooning can affect the driving behavior of adjacent manual vehicles. The purpose of this study is to analyze the lane change behavior of the manual vehicles in automated vehicle platonning environment and to conduct the experiment and questionnaire surveys in three stages. In the first stage, a video questionnaire survey was conducted, and responsive behaviors of manual vehicles were investigated. In second stage, the driving simulator experiments were conducted to investigate the lane change behaviors of in automated vehicle platonning environments. To analyze the lane change behavior of the manual vehicles, lane change durations and acceleration noise, which are indicators of traffic flow stability, were used. The driving behavior of manual vehicles were compared across different market penetration rates (MPR) of automated vehicles and human factors. Lastly, NASA-TLX (NASA Task Load Index) was used to evaluate the workload of the manual vehicle drivers. As a result of the analysis, it was identified that manual vehicle drivers had psychological burdens while driving in automated vehicle platonning environments. Lane change durations were longer when the MPR of the automated vehicles increased, and acceleration noise were increased in the case of 30-40 years old or female drivers. The results from this study can be used as a fundamental for more realistic traffic simulations reflecting the interaction between the automated vehicles and manual vehicles. It is also expected to effectively support the establishment of valuable transportation management strategy in automated vehicle environments.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.3
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• pp.461-473
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• 2015

Jinhae Bay located in the southern of Korean Peninsular is an important spawning area in Korea. By some preliminary studies it was measured several times that adult Pacific codes (Gadus microcephalus) were passed (swimming layer: 15 to 18 m) over a submerged sea tunnel (sea bottom: about 30 m) rather than another immigration route when the Pacific codes were tagged surgically with an acoustic transmitters and released inside of the Bay. There is a possibility that the Pacific codes and the other fishes use the route on the sea tunnel as an immigration route are affected by a human-generated underwater noise around the sea tunnel due to the sea tunnel traffic. On this study the 25-hour measurements of the underwater noise level by water layer were conducted with a hydrophone attached on a portable CTD and an underwater noise level meter during four seasons, and the acoustical characteristics of the underwater noise was analyzed. The mean traffic volume for one hour at the sea tunnel on the spring was shown the largest value of 1,408 [standard deviation (SD): 855] vehicles among four seasons measurement. The next one was ordered on the autumn [1,145 (SD: 764)], winter [947 (SD: 598)] and summer [931 (SD: 558)] vehicles. Small size vehicle was formed 84.3% of the traffic volume, and ultra-small size, medium size, large size and extra-large size of the vehicle were taken possession of 8.7%, 3.2%, 2.0% and 1.8%, respectively. On the daily change of the noise level in vertical during four seasons the noise level of 5 m-layer was shown the highest value of 121.2 (SD: 3.6) dB (re $1{\mu}Pa$), the next one was 10 m-layer [120.7 (SD: 3.5)], 2 m- and 15 m-layer [120.3 (SD: 3.5 to 3.7)] and 1 m-layer [119.2 (SD: 3.6)] dB (re $1{\mu}Pa$). In relation with the seasonal change of the noise level the average noise level measured during autumn was shown the highest value of 123.9 (SD: 2.6) dB (re $1{\mu}Pa$), the next was during summer [121.4 (SD: 3.2)], spring [118.0 (SD: 3.4)] and winter [116.5 (SD: 5.1)] dB (re $1{\mu}Pa$). In results of eigenray computation when the real bathymetry data (complicate shape of sea bed) was applied the average number of eigenray was 2.68 times (eigenrays: 11.03 rays) higher than those of model bathymetry (flat and slightly sloped sea bottom). When the real bathymetric data toward inside (water depth becomes shallow according to a distance between the source of noise and hydrophone) of the Bay was applied on the eigenrays calculation the number of the eigenray was 1.31 times (eigenrays: 12.49 rays) larger than the real bathymetric data toward outside (water depth becomes deep with respect to the distance). But when the model bathymetric data toward inside of the Bay was applied the number of the eigenray was 1.05 times (eigenrays: 4.21 rays) larger than the model bathymetric data toward outside.

• The Journal of the Korea Contents Association
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• v.10 no.5
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• pp.285-295
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• 2010

The frequency in which noise energy is generated, that is, the point where the preceding vowel ends is the cut-off frequency. Thereupon, this study intends to examine the correlations between, cut-off frequencies, cut-off frequencies changed by the following vowel, and cut-off frequencies and nasalance score, of fricatives and affricates with the subjects of children with the cleft palate and normal children. The subjects of this study are total 12 children residing in Seoul and Gyeonggi area. Six are the children diagnosed to have the cleft palate and whose chronological age are more than six, and another six are the normal children who are also more than six and whose chronological age and sex correspond to those of the former. Each subject was presented with nonsyllable environment and sentence environment(50 environment) of fricatives and affricates. Regarding meaningless syllable environment and sentence environment of fricatives and affricates, children with the cleft palate had lower cut-off frequencies than normal children. As a result of comparative study on correlations between cut-off frequencies and nasalance score of children with the cleft palate and normal children, it doesn't show statistically significant correlations in both meaningless syllable environment and sentence environment of normal children, but it has statistically significant correlations in sentence environment of children with the cleft palate.

• Journal of Korean Society of Forest Science
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• v.86 no.3
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• pp.352-364
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• 1997

This study examined and analyzed users' behavior to recreation forest facilities and their satisfaction to recreation forest in order to offer some basal data which would be helpful to create new recreation forest, to supply users' needs in exsiting recreation forest, and to make excellent maintenance of recreation forest. The results are as follows ; Restroom, campground and forest aromatic bath ground were the most popular facilities with the users of recreation forest. And restroom, snack stand and water cooler were the most required facilities by the users. Before using recreation forest, users' expectation to enjoy aesthetics of nature, to be released from their fatigue and to rest, was the highest one. And users were satisfied most as they expected most from recreation forest. The major variables played for users' satisfaction about facility allocation and its harmony to the forest, were how clean the facilities are, how well they are repaired and maintained, how much noise users make around them, how easy to use them, and how beautiful the surroundings are. Users' satisfaction variables about vegetation condition of recreation forest, were diversity of vegetation, the shade of trees, the reservation of the forest, and the accordance of vegetation with the surroundings. Users' satisfaction variables about facility condition in recreation forest, were how easy to access to the recreation facilities and restroom, how clean they are, how well the trash cans are allocated, how easy to access to the field kitchen. And how good the forest is protected and nurtured, how well the forest managers conduct users' behavior, how effectively recreation forest is guided and informed to the public, were their major satisfaction variables about the management of Recreation Forest.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.291-300
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• 2020

The cartridges used for illuminating a desired point or area are virtually limited in tests and evaluations because of limitations, such as noise during launch, the possibility of fires caused by illuminant charge, and the annual testable quantity. Therefore, to solve these problems, a ground fixed test, which replaces the firing test, or an evaluation method to perform limited tests, can be applied more efficiently. In this paper, the results of an 81mm illuminating cartridge, KM series performed in 2019 were analyzed comprehensively to identify the trends in reliability and quality characteristics and to estimate the shelf life. The shelf life was estimated to be at least 10 years based on the time when the lower confidence level reached 80% at a confidence level of 90%. Considering only major defects, the shelf life can be estimated to be approximately 23 years. On the other hand, the shelf life was estimated to be approximately 11 to 15 years and 25 to 28 years according to the effective illuminating time. Finally, an assessment plan of illuminating cartridges for the mortars was also presented as an improvement plan for an assessment method in the future.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2008.03a
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• pp.51-68
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• 2008

When the train enters into a tunnel a high speed, pressure waves are generated inside the tunnel. The pressure waves at propagate in a form of compression wave toward the tunnel exit and a fraction of the compression waves that arrives at the exit of the tunnel are discharged to outside of the tunnel and the remainder is reflected into the tunnel as expansion waves. The compression waves emitted from the tunnel does not radiate in a specific direction but in all directions. If the amplitude of the compression wave is great, it causes noise and vibration, and it is called "Micro-Pressure Wave." "Micro-Pressure Wave" must be considered as a decision for the optimum tunnel cross-section as the amplitude of the compression wave depends on train speed, tunnel length, area of tunnel and train. Therefore, this paper introduces the case study of Micro-Pressure Wave characteristics for determination of tunnel cross section in Honam high speed railway, the pressure inside the tunnel and the micro-pressure waves at tunnel exit were measured at Hwashin 5 tunnel in Kyungbu HSR line. At the same time. a test of train operation model was performed and then the measurement results and test results were compared to verify that the various parameters used as input conditions for the numerical simulations, which were appropriate. Also a model test was performed, in order to analysis of the Micro-Pressure Wave Mitigation Performance by Type of Hood at Entrance Portal.

• International Journal of Highway Engineering
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• v.15 no.2
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• pp.11-18
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• 2013

PURPOSES : This study presents the noise level and frequency characteristics investigated in the national highways with the consideration of various measuring conditions and/or methods. METHODS : The noise levels on the asphalt concrete pavement(ACP) and the jointed plain concrete pavement(JPCP) of the national highway were measured and analysed with respect to three variables, i.e., pavement type, surface condition, and measurement distance. The PASS-By method is utilized for the noise measurement and then using CPB spectrum analysis method with 1/3 octave bandwidth, the noise levels and frequency characteristics were calculated for two-second periods before and after the peak noise. RESULTS : Depending on the pavement type, the noise level was changed as the average noise levels are 73.3dB(A) and 78.3dB(A) for ACP and JPCP, respectively. With respect to the effect of surface condition, the average noise levels for crack H(high), M(medium), and L (low) sections are 77.4dB(A), 77.4dB(A), and 78.1dB(A), respectively. Regarding the measurement distance, 1.2meter difference in measuring location reduces 1.6dB(A) of noise level; the average noise levels at 5.3m and 7.5m from the centerline of outer lane are 72.8dB(A) and 71.2dB(A), respectively. It should be noted that the noise levels are slightly different as a function of vehicle speed and type. However, the overall trends for each case was similar. It was found that the domain frequency bands for ACP and JPCP were 400Hz~2000Hz and 500Hz~2000Hz, respectively. CONCLUSIONS : Based on the analysis with the measured noise date from national highway, it was concluded that the noise level and frequency band vary depending on the various conditions. It was also found that some variables significantly affect the noise level while others do not. With further systematic investigation, the comprehensive noise characteristics on the national highway can be achieved. Using such database, it is possible to develop the fundamental noise reduction technology.

• Journal of the korean Society of Automotive Engineers
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• v.18 no.5
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• pp.53-68
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• 1996

마그네슘이 자동차 경량화에 관심이 되는 이유는 근본적으로 CAFE 규제와 같이 경량화를 통한 화석연료의 소모를 크게 억제해야 한다는 사회적인 규제이나, 지난 10여년간의 기술발전으로 내식성이 나쁘다거나 취급이 위험한 금속이라는 인식이 크게 개선된 데에도 있다. 다른 경량금속에 대한 Mg 지금 가격의 비교조건이 호전되었고 향후 원소 재공급의 다변화가 추진되고 있는 것도 환경을 변화시킨 중요한 요인이다. 그간 중요한 경량화 대체 재료로 연구투자가 많았던 유기고분자 재료 및 FRP 등과 같은 복합재료는 폐기부품의 재활용이 어려움 때문에 호나경친화적인 단점이 부각되어, 이 소재의 증가가 주춤해 있다. 마그네슘의 경우에는 재활용이 가능하고, 진동흡수효과가 매우 커서 소음발생을 크게 줄일 뿐만 아니라, 주행 및 내구성시험에서 치수안정성이 좋고 많은 종류의 전자기기 사용에 의한 전자파 차폐효과도 큰 장점을 가지고 있다. 본 고에서는 Mg 다이캐스팅으로 자동차부품의 경량화 현황과 선진국에서 보는 전망을 미국을 중심으로 정리하고, 이와 관련한 Mg 다이캐스팅으로 자동차부품의 경량화 현황과 선진국에서 보는 전망을 미국을 중심으로 정리하고, 이와 관련한 Mg 기술적인 이슈와 시장전망도 서술하였다. 그리고 현재 우리나라의 연구계와 부품업계에서 추진하고 있는 연구개발 동향을 자동차 업계에 소개하는 의미도 있다. 이처럼 우리나라의 현황을 정리해 보는 것은 국내 자동차 산업이 국제적인 경쟁을 하고 있고 Mg기술과 원료확보에서 일본의 견제를 받고 있는 우리의 현실에서도 필요한 작업으로 생각된다.값들로 구성되는 형상을 내구 성능, 성형성등을 고려하여 최종 형상으로 결정한다. 내구성능의 예측은 금속부품의 내구수명 예측에 널리 이용되고 있는 방법이 방진 고무부품의 경우에도 적용 가능한지를 검토하고, 방진 고무부품에도 일반적으로 적용될수 있는 내구수명 예측방안의 개발 가능성을 타진해 보았다. 본 연구의 목표는 시제품을 제작하기 이전에 설계된 부품에 대한 스프링 상수 및 내구특성을 체계적으로 규명하여 제품 시험의 횟수를 줄이고, 보다 정밀한 제품을 제작할 수 있도록 하기 위한 것이다.세포수는 초기 배반포기배에서 팽윤 배반포기배로 진행됨에 따라 두배에서 세배 정도 증가되었음을 알 수 있었다. 또한, differential labelling과 bisbenzimide기법에서 얻어진 각각의 총세포수를 비교하였을 때 총세포수는 발달의 진행 정도에 따라 증가되며 그와 동시에 동일한 군 간의 세포수도 거의 유사함을 알 수 있었다. 따라서, ICM과 TE를 differential labelling하는 기법은 수정란의 quality를 평가하는데 매우 유용한 기법으로서 착상전 embryo 발달을 연구하는데 효과적으로 이용될 수 있다는 것을 시사한다. 고도의 유의차를 나타낸 반면 비수구, 초생수로구 및 Bromegrass 목초구 간에는 아무런 유의차가 인정되지 않았다. 7. 농지보전 처리구인 배수구와 초생수로구는 비처리구에 비해 낮은 침두 유출량과 낮은 토양유실량을 나타내었다.구보다 14% 절감되는 것으로 나타났다.작용하는 것으로 사료된다.된다.정량 분석한 결과이다. 시편의 조성은 33.6 at%

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.448-453
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• 2016

Erosion and abrasion caused by cavitation damage occur in fluid equipment, such as ships or impellers. Similarly, the equipment damage from noise and vibration can shorten its life. This study analyzed the importance of the parameter characteristics of the process optimization of HVOF (High Velocity Oxygen Fuel spraying), which is generally used in a variety of industries for enhancing the resistibility from the cavitation phenomenon. The surface of the ALBC3 substrate was coated with an amorphous powder as a filler metal according to the experimental design using the Taguchi method, and then the characteristics with each parameter were analyzed using a porosity measurement test. The optimal process conditions was a combustion pressure of 80psi, coating distance of 270mm, gun speed of 200mm/s, and powder feed rate of 25g/min as a result of the HVOF coating by applying the experimental design. The combustion pressure, coating distance and powder feed rate were more than 25% and indicated a similar contribution rate, but the contribution rate of the gun speed was 19%, which was slightly less than the others. The contribution rate with each parameter was only slightly significant. On the other hand, all four parameters were found to be important in the contribution rate aspects of the HVOF coating process.

• The Journal of Korean Medicine
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• v.20 no.1 s.37
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• pp.52-59
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• 1999

연구목적 : 뇌졸중환자에 기능회복도의 측정을 위해 가장 신뢰도가 높은 MBI에 대해서 순수하게 뇌졸중환자의 운동기능평가만을 위해 고안된 MAS의 상관성을 각 기간별로 분석하여 MAS의 운동기능평가척도로서의 객관성에 대해 연구한다. 또 한편으로 경과시간에 따른 운동기능 회복도의 차이를 전체그룹과 사상그룹에서 평가한다. 연구방법 : 1998년 1월부터 1998년 6월까지 6개월에 걸쳐 상지대학교 한의과대학 부속한방병원 내과에 입원하여 뇌졸중으로 진단된 환자 중 의식과 언어상태가 명료한 32명을 대상으로 하였다. 입원직후 사상의학과에 의뢰하여 QSCCII 시스템에 의하여 체질진단을 받은 후 본원 운동기능평가실에서 입원직후, 입원 후 2주와 4주 등 3회에 걸쳐 Modified Barthel Index(MBI)와 Motor Assessment Scale(MAS)을 시행하였다. 각 환자에 대한 검사는 2명의 한방순환기내과 전문의와 전공의에 의해 환자에 대한 사전 정보 없이 이루어졌다. 연구결과 : 통계처리는 상관분석을 위해서는 Pearson correlation coefficient, 사상체질에 있어서 각 경과시간에 따른 점수변화는 Repeated ANOVA, 일반적특성 분석에는 Descriptive analysis가 사용되었고, 프로그램은 SPSS/PC+ 7.5 version을 사용하였다. 1. 뇌졸중 환자의 사상의학적인 분포는 태음인이 56.3%로 가장 많았고, 소양인이 28.1%, 소음인이 12.5%, 태양인이 3.1%이었으며, 연령별로는 50대가 32.6%로 가장 많았으며, 평균연령은 60.9세였다. 2. 경과시간에 따른 사상체질간의 MBI, MAS 평균점수변화는 MBI, MAS 모두 반복측정 분산분석 결과 입원당시와 2주 후, 입원당시와 4주 후에서 모두 P<0.001의 범위에서 통계학적으로 유의하게 증가하였고, 경과시간과 사상체질간의 교호작용은 없었다. 3. MBI, MAS 모두 각 항목과 기능별 분류군에서도 경과시간에 따른 평균점수의 변화는 P<0.001 범위에서 통계학적으로 유의하게 증가하여 한방치료의 효과가 있음을 보여주었다. 4. MBI와 MAS의 경과시간별 Pearson 상관성 분석결과 입원당시의 MBI와 입원당시의 MAS에서, 2주 후의 MBI와 입원당시, 2주 후, 4주 후의 MAS에서, 4주 후의 MBI와 입원당시, 2주, 4주 후의 MAS에서 모두 높은 상관성을 보여, 두 평가방법 간에는 상관성이 높다고 본다.