• Journal of Navigation and Port Research
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• v.27 no.4
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• pp.471-478
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• 2003

In the Signalized Intersection, the capacity analysis is conducted with a large amount of input data such as road way, traffic and signal condition. but the level of service(LOS) is determined by delay estimated as a measure of effectiveness (MOE) based on this procedure. However, It is under the circumstances which are not considered for the errors caused by the uncertainty of input data in the field(the turing volumes, lane geometry, signal timing, grade of approach lane, percentage heavy vehicles, peak hour factor and arrival type etc.) as become the bases in the determination of the capacity and LOS. It includes the problem of reliability which is not verified for the capacity and LOS estimated. So, this study is to suggest the minimization of their influences by examining whether the uncertainty of input data such as the traffic volume, percentage of heavy vehicles and roadway geometry on the approach lane in the intersection under the study affects the capacity analysis and LOS determination.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.111-120
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• 2010

This study evaluated strength properties of recycled asphalt concretes using warm-mix technology. Granite with maximum size of 13mm and penetration grade of 80-100 virgin binder were used for mixing in recycled mixtures. Mix design was performed using 20% and 30% RAP(coarse : fine= 6 : 4) contents. GPC, penetration, absolute viscosity and kinematic viscosity were measured for determining ratio of two warm-mix additives (Evotherm and Sasobit). Low-density polyethylene(LD) used as asphalt modifier for improving stiffness of recycled WMA mixtures in this study. Therefore, a total of 11 mixtures were prepared in this study; 8 warm-mix recycled mixtures(2 RAP contents${\times}$2 warm-mix additives${\times}$2 modifiers), 2 hot-mix recycled mixtures and 1 HMA virgin mixture(control). Deformation strength, indirect tensile strength, moisture sensitivity, permanent deformation by wheel tracking tests were measured out for evaluating fundamental properties of recycled asphalt concretes using warm-mix technology.

• Journal of the Korean Geotechnical Society
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• v.22 no.10
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• pp.33-45
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• 2006

C.S.G is a material made by adding cement and water to rock-like material such as riverbed gravel or excavation muck that can be obtained easily near dam si. Recently, the use of C.S.G is gradually increasing as the construction material for dam, road, revement and so on. Commonly, the strength characteristics of C.S.G is affected by various influence factors such as grade, unit cement, age and water contents. In this study, a series of compaction test and unconfined compressive strength test were performed to investigate the relationship between a strength and influence factors such as three kinds of gradation, age, unit cement and water contents with riverbed gravel in Hwa Buk dam. The results show that strength Properties of C.S.G is variously affected by these influence factors. Especially, gradation and water contents are found to be very important factors fur determining the strength of C.S.G material. And, from the results of experimental study, the correlation equations between uncompressive strength and these factors are proposed.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.4
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• pp.83-93
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• 2013

Land Suitability Assessment can help to evaluate whether to preserve or to develop through analysis of various land characteristics. So, the evaluation index and method are very important for making the best result. The principle objective of this dissertation is to identify effective method that can make up for the distortion of land suitability value in the forest bordering the management area. The objective area of this study is comparative flat Jeungpyeong-gun. The procedures of the study are as follows. First, implement land suitability assessment as the normal index on Guideline. Second, verify land suitability grade about the forest bordering the management area. The third, redo land suitability assessment as two alternative index on $^*$Guideline. The fourth, identify effective method between normal index and alternative index. The results of this tests show that the development suitability value is higher than preservation suitability value in the forest bordering the management area near existing development area. For that reason, this study needed to use substitution index in order to make up for the weakness. The level of land price and distance from road were main considerations. Finally, the derivative model is as follows. The derivative model confirmed the best assessment method in the forest bordering the management area near existing development area.

• Journal of Korean society of Dental Hygiene
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• v.8 no.2
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• pp.93-106
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• 2008

This study is to enforce to ready basic data of effective school dental health education for dental caries prevention， relation knowledge of class, feeding practice and snack intake preference actual conditions, food and caries executed investigation by own recording way using questionnaire consisted of dental health education awareness to some business world man high school locating in Kyonggi Province. Analyzes result that total 487 people respond in SPSS WIN 13.0 programs and got following sequence The obtain result were as follows 1. Results about habit of breakfast was the most by 36.1% a student who have breakfast every day, and a student who hardly eat dominated 32.9%. Second-year student hardly had breakfast (p<.01). 2. A student who answer that snack kind that often eat was cookies and snack kind was the most by 37.2%, and a student who answer that symbol drink was a carbonated drink was the most by 50.9%. 3. Relation knowledge degree appeared grand mean among 18 points perfect score by 12.36 with food and caries. Third-year student knowledge degree was the highest, and second-year student was the lowest knowledge degree by class (p<.01). 4. Existence and nonexistence of experience of dental health education appeared a student who experience that take dental health education does not exist by 57.1%. There was experience that take dental health education as class is low by class, and as class is high, experience did not exists (p<.05). 5. Time that take dental health education for the first time was the most by 56.7% a student who respond 'Babyhood', grade in school is low by class 'Babyhood', and is high by class responded 'Middle school'(p<.05). 6. Awareness of dental health education necessity 'may educate dental health and does not' a student 56.3%, half was looked attitude which students who exceed are insincere about dental health education necessity. 7. When educate dental health, contents was the most by 44.6% 'brushing and mouth article directions' to be educated importantly, and was expose by caries 31.2%, gum disease 10.1%, scaling 9.0%, prosthetic dentistry and implant 5.1% period of ten days, third-year student 50.8% said that 'brushing and mouth article directions' is important (p<.05). Dental health education is practiced during life, and is a teaching that should be remembered. Need to develop epoch-making and interesting education program that is correct in subject to do as quickly as possible, and should be achieved major road of dental hygienist. Dental hygienist will have to settle as quickly as possible as expert of prevention that is natural business and education and help in dental health education development under effort between country and dental association effective.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.6
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• pp.1357-1366
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• 2015

This study (II) aims to draw up the future-oriented construction policy recommendations based on the outcomes as a result of a broad research and conducting questionnaire surveys on the arguable issues raised by construction engineers for roads and bridges in the course of previous study (I) implementation. As for the question of "The term 'Construction Management (CM)' which currently is defined in two (2) ways", 45% of respondents have answered that two (2) different types of CM should be unified into one (1) CM type as is the case in most advanced countries. About the question of "The ways to educate the CM professionals", many respondents have preferred to acquire CM professional certificate after receiving education for a certain period of time from private CM training institutions. As for the question of The revised draft that the ICEC grade of special engineers for design, construction and quality control areas shall be "more than 78 points from a more than 75 points by the original draft." 52% of respondents preferred to maintain the original draft. About the question of "The reason why the CM system has not been working well yet." 62% of respondents have answered that the staff members who are in charge of handling public project procurements are concerned about the fact that their roles (or activities) might be deprived as a result of CM adoption. In order for the CM system to be activated, based on the notion that the construction projects must be out soured, the reshuffle of the headquarter organization of Ministry of Land, Infrastructure and Transportation (MLIT) should be preceded.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.5
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• pp.487-498
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• 2010

This article presents an effect of deicer such as $CaCl_2$(calcium chloride) and EFD(Eco-Friendly Deicer) composed by organic acids on the survival and growth of plant. Pine and bush clover which are main natural species on the road side, and young radish and kidney bean which are cultivation species used in this test that responses of survival and growth were analyzed as grade concentration of deicers. Bush clover showed the most sensitive survival response among 4 species to the deicer. Pine growth didn't have statistical significance as the kind of deicers and concentration variation, but growths of bush clover and kidney bean showed growth inhibition in concentration more than 3% of $CaCl_2$ and EFD1. The results of survival and growth for $CaCl_2$(calcium chloride) demonstrated that young radish and pine are tolerant species and bush clover and kidney bean are sensitive species. Although EFD1 manufactured by chemical showed the negative effect on the survival and growth of plants, EFD2 made with waste compost was confirmed that it has the positive influence to the survival and growth of the both sensitive and tolerant plant species for chloride.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.3
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• pp.301-310
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• 2013

Jet fans are installed in road tunnels in order to maintain critical velocity when fire occurs. Generally the number of jet fans against fire are calculated by considering critical velocity and flow resistance by wall friction, vehicle drag force, thermal buoyance force and natural wind. In domestic case, thermal buoyance force is not considered in estimating the number of jet fans. So, in this study, we investigated the pressure loss due to the thermal buoyance force induced by tunnel air temperature rise and the impact of thermal buoyance force on the number of jet fans by the numerical fire simulation for the tunnel length(500, 750, 1000, 1500, 2000, 3500m) and grade (-1.0, -1.5, -2.0%). Considering the thermal buoyance force, number of jet fans have to be increased. Especially in the case of 100MW of heat release rate, the pressure loss due to thermal buoyance force exceed the maximum pressure loss due to vehicle drag resistance, so it is analyzed that number of 2~11 jet fans are needed additionally than current design criteria. Thus, in case of estimating the number of jet fans, it must be considered of thermal buoyance force induced tunnel air temperature rise by fire.

• Journal of Korean Society of Transportation
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• v.32 no.6
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• pp.662-674
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• 2014

In this study, accident frequency prediction models were constructed by collecting variables such as geometric structures, safety facilities, traffic volume and weather conditions, land use, highway design-satisfaction criteria along 780km (4,372 sections) of 4 lane-highways over 8 areas. As for models, a fixed parameter model and a random parameter model were employed. In the random parameter model, some influences were reversed as the range was expressed based on specific probability in the case of no fixed coefficients. In the fixed parameter model, the influences of independent variables on accident frequency were interpreted by using one coefficient, but in the random parameter model, more various interpretations were took place. In particular, curve radius, securement of shoulder lane, vertical grade design criteria satisfaction showed both positive and negative influence, according to specific probability. This means that there could be a reverse effect depending on the behavioral characteristics of drivers and the characteristics of highway sections. Rather, they influence the increase of accident frequency through the all sections.

• International Journal of Highway Engineering
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• v.8 no.4 s.30
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• pp.135-143
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• 2006

This study evaluated the fatigue resistance characteristics of hot-mix recycled asphalt mixtures which were prepared by a new blending method. Since the binder of RAP shows higher viscosity without being rejuvenated in the ordinary recycled mixture, this new(modified) blending method was developed for obtaining more uniform level of binder viscosity in the recycled mixture. Cold-planned RAP was collected and mix design was performed using 15% RAP content for two virgin aggregate, gneiss and granite. Penetration grade of 60-80 asphalt was used in mixing recycled mixture together with a polymer modifier, LDPE. Indirect tensile fatigue tests were carried out to evaluate characteristics of fatigue resistance of performance of recycled asphalt mixtures. The recycled mixtures with LDPE 6% showed higher repeated loading fatigue life. Fatigue life ratio of new(N) mixing method mixtures was approximately 0.6-0.7 before aging and 0.8-1.0 after aging treatment of ordinary(O) mixing method mixture. This means the N mixture becomes stronger with aging process increase. If further aging is treated, N mixture may be showing stronger resistance than O mixture.