• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.21 no.6
• /
• pp.21-35
• /
• 2022

With the support of local and central governments, various incentive policies for "green" cars have been established, and the number of electric vehicle users has been rapidly increasing in recent years. As a result, much attention is being given to establishing a user-centered charging infrastructure. A standard for the number of electric vehicle chargers to be supplied is being prepared based on building characteristics, but there is quite limited research on the appropriate ratio of slow and fast chargers based on the characteristics of each place. Therefore, this study derived an appropriate penetration ratio based on data about the distribution ratio of common slow chargers. These data were collected using a survey of actual electric vehicle users. Next, an analysis was done on how to categorize the needs of charging environments and to determine what criteria or characteristics to use for categorization. Based on the results of the survey analysis, three types of places were derived. Type-1 places require 10% of chargers to be slow chargers, Type-2 places require 40-60% of chargers to be slow chargers (i.e., around equal distribution of slow and fast chargers), and Type-3 places require more than 80% of chargers to be slow chargers. The required levels of slow chargers were classified by place type and by individual using latent class cluster analysis, which made it possible to categorize them into five clusters related to socioeconomic variables, vehicle characteristics, traffic, and charging behaviors. It was found that there was a high correlation between charging behavior, weekend travel behavior, gender, and income. The results and insights from this study could be used to establish charging infrastructure policies in the future and to prepare standards for supplying charging infrastructure according to changes in the electric vehicle market.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• autumn
• /
• pp.180-185
• /
• 2003

The increase of traffic over a bridge has been emerged as one of the most severe problems in view of bridge maintenance, since the load effect caused by the vehicle passage over the bridge has brought out a long-term damage to bridge structure, and it is nearly impossible to maintain operational serviceability of bridge to user's satisfactory level without any concern on bridge maintenance at the phase of completion. Moreover, bridge maintenance operation should be performed by regular inspection over the bridge to prevent structural malfunction or unexpected accidents front breaking out by monitoring on cracks or deformations during service. Therefore, technical breakthrough related to this uninterested field of bridge maintenance leading the public to the turning point of recognition is desperately needed. This study has the aim of development on automated inspection system to lower surface of bridge superstructures to replace the conventional system of bridge inspection with the naked eye, where the monitoring staff is directly on board to refractive or other type of maintenance .vehicles, with which it is expected that we can solve the problems essentially where the results of inspection are varied to change with subjective manlier from monitoring staff, increase stabilities in safety during the inspection, and make contribution to construct data base by providing objective and quantitative data and materials through image processing method over data captured by cameras. By this system it is also expected that objective estimation over the right time of maintenance and reinforcement work will lead enormous decrease in maintenance cost.

• Journal of Food Hygiene and Safety
• /
• v.30 no.1
• /
• pp.59-64
• /
• 2015

This study compared the content change of physiological active substances according to the extraction condition when we generally drink the extractive of Schisandra fruit with using water. Physiological active substances of the Schisandra fruit, schizandrin, gomisin A and gomisin N were analysed with HPLC. The results of extracting 1 dose of the Schisandra fruit tea, which is some as 1 g of Schisandra fruit, in 100 mL of water by differing the extraction type, extraction temperature and extraction time were of the followings. The total content of schizandrin, gomisin A and gomisin N of powder type in $26^{\circ}C$ leaching was the highest (p < 0.05) as the leaching content of 24 hours (5.54 mg/g) showed difference with different times and the contents of raw type Schisandra fruit were less than 0.1 mg/g in all of extraction time. The contents of powder type Schisandra fruit in $60^{\circ}C$ heating extraction was over 4.50 mg/g except for the 5 minute (2.94 mg/g), and the contents of raw Schisandra fruit were less than 0.3 mg/g. In case of $100^{\circ}C$ heating extraction, the contents of powder type Schisandra fruit showed over 5.10 mg/g in every time zone, and the raw type Schisandra fruit was less than 1.0 mg/g.

• Journal of Korean Ophthalmic Optics Society
• /
• v.8 no.2
• /
• pp.37-45
• /
• 2003

This study investigated that total 1071 reading glasses wearers (male 432, female 639) without any eye disease or deformation in eyelid, orbit, eyeball (over 50 years old), were tested. Reading pupillary distance of 524 (male 202, female 322) of 1071 were examined and reading glasses power was examined for all 1071 patients. As a result of average reading diopters analysis by sex. male had S+2.34Dptr, female had S+2.23Dptr in average and male had a little more average power than female by 0.11Dptr. However, the difference was not much enough and by aging accommodation reduction changes were applied to both male and female. After dividing ready-made reading glasses on sale in optical shops into 5 groups by F.P.D. the average D.B.O.C(distance between optical centers) of each 5 group was examined (1st group 64.04 mm, 2nd group 66.96 mm, 3rd group 68.28 mm, 1th group 62.03 mm, 5th group 72.00 mm : the average of all groups was 66.96 mm : each group included 3 random samples : 195 ready-made reading glasses were measured), and compared with the average reading P.D of males and females (male 60.04 mm, female 58.23 mm). The result showed D.B.O.C of ready-made reading glasses on sale was bigger than the average reading P.D of them. The result reviewed the average range for male was $0.23{\Delta}(minimum){\sim}5.06{\Delta}(maximum)$, and for female was $0.46{\Delta}{\sim}5.79{\Delta}$. In conclusion when wearing ready-made reading glasses, female got more effected by average $0.45{\Delta}$ because reading P.D of female was smaller than that of male.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.6
• /
• pp.78-83
• /
• 2020

The information and knowledge of modern society in the 2lst century is changing rapidly. Based on this social change, the ministry of education introduced STEAM (Science Technology Engineering Art Music) in 2011 to foster creative convergence talents. Therefore, this study is based on the PBL model that learners participate in the class voluntarily to develop appropriate talents in the 21st century. The combined subjects were English, which is the world's official language, and Science, which is found in almost all the fields with the development of the 4th industrial revolution. As a result, learners could define the problems and solutions during the English class and take part in the group activity actively to obtain the problems and solutions of environmental pollution during the Science class. Through this, learners answered that they had a great understanding of learning (86%), high motivation for learning (100%), improved self-confidence (100%), and improved collaboration and creativity (100%). Unfortunately, this study does not progress actively due to the entrance exams, which still require accurate answers rather than the necessity and effectiveness of convergence education. To foster talents suitable for the present age, more active research should be applied to a range of educational sites.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.06a
• /
• pp.586-591
• /
• 2005

우리나라는 에너지의 안정적 공급과 에너지이용 과정에서 발생하는 환경적, 안보적 외부성을 최소화하는 에너지수급 구조를 마련하기 위해 2003년 12월 '제2차 신재생에너지 기술개발 및 이용보급 기본계획(2003-2012)'을 발표하였다. 이 계획에서는 2011년까지 전체 TPES의 $5\%$를 신재생에너지로 공급하는 것을 정책목표로 수립하고 수소, 태양광 그리고 풍력기술을 중점적으로 추진하기로 하였다. 특히 수소부문에서는 주택 및 건물용, 발전용, 수송용 연료전지의 개발을 중심으로 개발하여 세계 기술시장의 $20\%$를 확보한다는 계획을 발표하였다. 이러한 기술 잠재력을 기반으로 우리 정부도 미국이나 일본과 같이 수소경제로의 전환을 준비하고 있으며 2020년대 이후 우리나라의 에너지부문은 새로운 국면에 접어들 것으로 전망된다. 에너지나 환경기술의 효과적 인 개발을 위해서는 이들 기술의 직접적인 비용측면에 대한 분석 즉 경제성 평가와 새로운 기술변화로 인한 중장기적인 사회경제적 영향평가가 선행되어야 한다. 이러한 평가는 대상 기술의 사회경제적 파급효과가 광범위할수록 더욱 복잡한 분석이 요구된다. 본 연구의 주제인 수소에너지기술은 지금까지 이용되던 것과는 전혀 새로운 에너지캐리어(carrier)를 개발하는 것으로 에너지부문 및 여타 다른 산업부문이 공유하고 있는 에너지 관련 인프라의 전면적인 조정이 요구되며 에너지 이용과 관련된 사회경제적 측면의 급속한 변화를 수반한다. 본 연구는 수소경제로의 이행에 대한 사회경제적 영향평가의 방법론적 요소들과 기법을 제시한다."중등도 독성"으로 나타났다 이상의 결과는 전기도금을 이용하여 교정용 선재의 직경을 증가시키는 방법이 임상에 적용되기 위해서는 세포독성을 줄이기 위한 추가의 연구가 필요함을 시사하였다.의하게 가장 낮은 정지. 운동 마찰력을 보였고 브라켓-호선 각도가 증가함에 따라 유의하게 정지, 운동 마찰력도 증가하였다 (P<0.001)%$ 낮추지만(p value=0.260) 평균 $D_{max}$는 거의동일 하여($0.3\%$ 감소, p value=0.867), 전통적인 방법보다 우수성이 크게는 없는 것으로 평가되었다. 그러나 환자의 체곡선이 보상체와 잘 일치하는 경우에는 DII가 $18\%$까지 감소하였다. 결론 : Multistatic field 방법은 모든 환자에 대하여 선량분포의 균일성을 전반적으로 향상시키는 효과적인 방법으로 평가되는 반면 공용보상체의 사용은 보상체의 크기가 환자의 체 윤곽과 잘 일치하는 경우만 효과적으로, 적용의 범위에는 한계가 있는 방법으로 평가되었다.비교하여 계통에 따르는 차이가 있음을 알 수 있었다. 그러므로 가임기 여성의 방사선 진단 및 치료시 Rugh의 10일 법칙을 적용하여 착상전기 방사선 조사로 인한 부작용들을 적극적으로 예방하는 것이 매우 중요하다고 생각한다.equirements of the prematured infants during the early weeks of life. 모든 치근단 수준에서 비표준화 medium 크기 master cone 사용군이 ISO 표준화 규격의 master cone 사용군에 비해

• Journal of Korean Society of Steel Construction
• /
• v.24 no.1
• /
• pp.101-108
• /
• 2012

The orthotropic steel deck bridge made by using relatively thin steel plate, and structural members such as transverse and longitudinal ribs, cross beam, etc. in the bridge are fabricated with complex shape by welding. Therefore, the possibility occurring deformation and defects by welding is very high, and stress states in the welded connection parts are very complex. Also, the fatigue cracks in orthotropic steel deck bridge are happening fromthe welded connection parts of secondary member than main member. However, stress evaluation for main members is mainly carried out in the design process of the bridge, detailed stress evaluation and characteristic analysis is not almost reviewed in the structural details which fatigue crack occurred. For the orthotropic steel deck bridge with open ribs which has been serviced for 29 years, in this study, the cause of fatigue crack is investigated and the fatigue safety of the bridge is examined based on fieldmeasurement by the loading test and real traffic condition. Also, structural analyses using gridmodel and detailed analysis model were carried out for the welded connection parts of longitudinal rib and diaphramthat fatigue crack occurred. Additionally, the behavior characteristics due to running vehicles were investigated by using influence area analysis for these structural details, and the occurrence causes of fatigue crack in the target bridge were clarified.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.39C no.12
• /
• pp.1250-1260
• /
• 2014

In this paper, a novel resource scheduling, which is used for hub network based long distance airborne tactical communication, is proposed. Recently, some countries of the world has concentrated on developing data rate and networking performance of CDL, striving to keep pace with modern warfare, which is changed into NCW. And our government has also developed the next generation high capacity CDL. In hub network, a typical communication structure of CDL, hybrid FDMA/TDMA can be considered to exchange high rate data among multiple UAVs simultaneously, within limited bandwidth. However, due to different RTT and traffic size of UAV, idle time resource and unnecessary packet transmission delay can occur. And these losses can reduce entire efficiency of hub network in long distance communication. Therefore, in this paper, we propose RTT and data traffic size based UAV scheduling, which selects time/frequency resource of UAVs by using iterative sorting algorithm. The simulation results verified that the proposed scheme improves data rate and packet delay performance in low complexity.

• International Journal of Highway Engineering
• /
• v.6 no.4 s.22
• /
• pp.75-89
• /
• 2004

Long term performance of concrete pavement significantly depends on the given construction and environmental condition. It means that random cracks and extreme crack width due to inappropriate quality control at the early age might lead to decreasing the pavement service life. The temperature and moisture during the construction, cement and aggregate types, curing condition are major components to affect the quality of the concrete pavement at the early age. First of all, the high temperature differential, that is made by increasing air temperature and the heat of cement hydration, is known as the major contributor to severe cracks. In this study, tent covering was used for controlling temperature of the concrete slab. The field measurement data indicates that the effect of the tent covering is very significant to decrease possibilities of random crack occurrence and curling stress and enhance the long-term concrete strength. HIPERPAV(High PERformance PAVing software), a program predicting the strength and stress of an earty-age concrete pavement (72 hour after placement), is used for simulating the effects of tent covering. The HIPERPAVE results showed that the section with the tent covering has higher reliability than the section without the tent covering by 22.5%. In details, reliability is increased 72.5% (without the tent covering) to 95% (with the tent covering).

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.18 no.3
• /
• pp.84-92
• /
• 2014

In this study, vibrational tendon tension measurement methods are applied to estimate tension of external tendons used in segmental post-tensioned bridges. The acceleration of various length type of tendons is measured and natural frequencies are obtained using FFT (Fast Fourier Transform). The obtained natural frequencies are within 1% error regardless of sensor direction and location. On the basis of natural frequency of tendon, estimation of the tendon tension is performed by using many types of solutions such as string theory equation, multi mode estimation, practical formula estimation and stiff string with clamped-clamped boundary conditions. The results are compared with each other and have shown that the flexural stiffness is not negligible in tendons of this type causing the vibration mode to be inharmonically related. The results have shown that the method using stiff string equation with clamped-clamped boundary conditions is more accurate than the other methods. Application example of in-service bridges has shown that force distribution effects from friction at deviation blocks can be effectively detected.