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An Experimental Study for Recycling of the Waste PET Bottle as a Fine Aggregate for Lightweight Concrete (폐 PET 병을 경량콘크리트용 잔골재로 재활용하기 위한 실험적 연구)

  • Choi Yun-Wang;Moon Dae-Joong;Jung Moon-Young;Cho Sun-Kyu
    • Journal of the Korea Concrete Institute
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    • v.16 no.1 s.79
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    • pp.79-87
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    • 2004
  • The qualify of lightweight aggregate made from waste PET bottle(WPLA) and the workability, the unit weight and strength property of concrete with WPLA were investigated for the purpose of recycling the waste PET bottles as lightweight concrete fine aggregate. This study indicated a good result that WPLA should be replaced with less than $50\%$ of natural fine aggregate. When WPLA was replaced with $50\%$ of natural fine aggregate, the specific gravity and water absorption of mixed fine aggregate were greatly reduced about 23 and $75\%$ respectively in comparison with those of river sand. The quality of WPLA affected on the properties of lightweight aggregate concrete. The workability of fresh concrete with WPLA(WPLAC) was improved with increasing the replacement ratio of WPLA and water cement ratio. Slump increasing ratio of the former showed about $45 {\~} 120\%$ because that a specific gravity of fine aggregate was decreased from 2.6 to 1.7. The unit weight of concrete with $75\%$ WPLA was decreased about $17\%$ in comparison with that of control concrete. Furthermore, the compressive strength of concrete with 25 and $50 \%$ WPLA at the age of 28 days increased higher than 30 MPa regardless with water cement ratio (W/C=45, 49 and $53\%$) of this study. Specific strength of concrete with $25\%$ WPLA, $15.11{\times}10^3 MPa{\cdot}m^3/kg$, was higher than that of contro concrete in water cement ratio of $49\%$. The compressive strength-splitting tensile strength ratio and compressive strength-modulus of elasticity ratio of WPLAC were similar to that of nomal lightweight aggregate concrete. This results showed a good estimation that WPLA will be able to recycled as a fine aggregate for lightweight concrete.

A Knowledge-based Approach for the Estimation of Effective Sampling Station Frequencies in Benthic Ecological Assessments (지식기반적 방법을 활용한 저서생태계 평가의 유효 조사정점 개수 산정)

  • Yoo, Jae-Won;Kim, Chang-Soo;Jung, Hoe-In;Lee, Yong-Woo;Lee, Man-Woo;Lee, Chang-Gun;Jin, Sung-Ju;Maeng, Jun-Ho;Hong, Jae-Sang
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.16 no.3
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    • pp.147-154
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    • 2011
  • Decision making in Environmental Impact Assessment (EIA) and Consultation on the Coastal Area Utilization (CCAU) is footing on the survey reports, thus requires concrete and accurate information on the natural habitats. In spite of the importance of reporting the ecological quality and status of habitats, the accumulated knowledge and recent techniques in ecology such as the use of investigated cases and indicators/indices have not been utilized in evaluation processes. Even the EIA report does not contain sufficient information required in a decision making process for conservation and development. In addition, for CCAU, sampling efforts were so limited that only two or a few stations were set in most study cases. This hampers transferring key ecological information to both specialist review and decision making processes. Hence, setting the effective number of sampling stations can be said as a prior step for better assessment. We introduced a few statistical techniques to determine the number of sampling stations in macrobenthos surveys. However, the application of the techniques requires a preliminary study that cannot be performed under the current assessment frame. An analysis of the spatial configuration of sampling stations from 19 previous studies was carried out as an alternative approach, based on the assumption that those configurations reported in scientific journal contribute to successful understanding of the ecological phenomena. The distance between stations and number of sampling stations in a $4{\times}4$ km unit area were calculated, and the medians of each parameter were 2.3 km, and 3, respectively. For each study, approximated survey area (ASA, $km^2$) was obtained by using the number of sampling stations in a unit area (NSSU) and total number of sampling stations (TNSS). To predict either appropriate ASA or NSSU/TNSS, we found and suggested statistically significant functional relationship among ASA, survey purpose and NSSU. This empirical approach will contribute to increasing sampling effort in a field survey and communicating with reasonable data and information in EIA and CCAU.

Developing Fire-Danger Rating Model (산림화재예측(山林火災豫測) Model의 개발(開發)을 위(爲)한 연구(硏究))

  • Han, Sang Yeol;Choi, Kwan
    • Journal of Korean Society of Forest Science
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    • v.80 no.3
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    • pp.257-264
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    • 1991
  • Korea has accomplished the afforestation of its forest land in the early 1980's. To meet the increasing demand for forest products and forest recreation, a development of scientific forest management system is needed as a whole. For this purpose the development of efficient forestfire management system is essential. In this context, the purpose of this study is to develop a theoretical foundation of forestfire danger rating system. In this study, it is hypothesized that the degree of forestfire risk is affected by Weather Factor and Man-Caused Risk Factor. (1) To accommodate the Weather Factor, a statistical model was estimated in which weather variables such as humidity, temperature, precipitation, wind velocity, duration of sunshine were included as independent variables and the probability of forestfire occurrence as dependent variable. (2) To account man-caused risk, historical data of forestfire occurrence was investigated. The contribution of man's activities make to risk was evaluated from three inputs. The first, potential risk class is a semipermanent number which ranks the man-caused fire potential of the individual protection unit relative to that of the other protection units. The second, the risk sources ratio, is that portion of the potential man-caused fire problem which can be charged to a specific cause. The third, daily activity level is that the fire control officer's estimate of how active each of these sources is, For each risk sources, evaluate its daily activity level ; the resulting number is the partial risk factor. Sum up the partial risk factors, one for each source, to get the unnormalized Man-Caused Risk. To make up the Man-Caused Risk, the partial risk factor and the unit's potential risk class were considered together. (3) At last, Fire occurrence index was formed fire danger rating estimation by the Weather Factors and the Man-Caused Risk Index were integrated to form the final Fire Occurrence Index.

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Performance effectiveness of pediatric index of mortality 2 (PIM2) and pediatricrisk of mortality III (PRISM III) in pediatric patients with intensive care in single institution: Retrospective study (단일 병원에서 소아 중환자의 예후인자 예측을 위한 PIM2 (pediatric index of mortality 2)와 PRIMS III (pediatric risk of mortality)의 유효성 평가 - 후향적 조사 -)

  • Hwang, Hui Seung;Lee, Na Young;Han, Seung Beom;Kwak, Ga Young;Lee, Soo Young;Chung, Seung Yun;Kang, Jin Han;Jeong, Dae Chul
    • Clinical and Experimental Pediatrics
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    • v.51 no.11
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    • pp.1158-1164
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    • 2008
  • Purpose : To investigate the discriminative ability of pediatric index of mortality 2 (PIM2) and pediatric risk of mortality III (PRISM III) in predicting mortality in children admitted into the intensive care unit (ICU). Methods : We retrospectively analyzed variables of PIM2 and PRISM III based on medical records with children cared for in a single hospital ICU from January 2003 to December 2007. Exclusions were children who died within 2 h of admission into ICU or hopeless discharge. We used Students t test and ANOVA for general characteristics and for correlation between survivors and non-survivors for variables of PIM2 and PRISM III. In addition, we performed multiple logistic regression analysis for Hosmer-Lemeshow goodness-of-fit, receiver operating characteristic curve (ROC) for discrimination, and calculated standardized mortality ratio (SMR) for estimation of prediction. Results : We collected 193 medical records but analyzed 190 events because three children died within 2 h of ICU admission. The variables of PIM2 correlated with survival, except for the presence of post-procedure and low risk. In PRISM III, there was a significant correlation for cardiovascular/neurologic signs, arterial blood gas analysis but not for biochemical and hematologic data. Discriminatory performance by ROC showed an area under the curve 0.858 (95% confidence interval; 0.779-0.938) for PIM2, 0.798 (95% CI; 0.686-0.891) for PRISM III, respectively. Further, SMR was calculated approximately as 1 for the 2 systems, and multiple logistic regression analysis showed ${\chi}^2(13)=14.986$, P=0.308 for PIM2, ${\chi}^2(13)=12.899$, P=0.456 for PRISM III in Hosmer-Lemeshow goodness-of-fit. However, PIM2 was significant for PRISM III in the likelihood ratio test (${\chi}^2(4)=55.3$, P<0.01). Conclusion : We identified two acceptable scoring systems (PRISM III, PIM2) for the prediction of mortality in children admitted into the ICU. PIM2 was more accurate and had a better fit than PRISM III on the model tested.

Estimation of Productivity and Organic Hanwoo Carrying Capacity per Unit Area of Whole Crop Wheat and Triticale by Application of Organic Fertilizer and Legumes-Mixed Sowing (유기질비료 시용과 콩과 사료작물의 혼파에 따른 총체밀과 트리트케일의 생산성과 단위면적당 유기 한우 사육능력 추정)

  • Jo, Ik-Hwan
    • Korean Journal of Organic Agriculture
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    • v.21 no.2
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    • pp.207-217
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    • 2013
  • This study was conducted to estimate organic Hanwoo carrying capacity when whole crop wheat and triticale as winter forage crops were grown on different applying sources (no fertilizer, organic fertilizer or cattle slurry), and mixed sowing in combination with hairy vetch and forage pea at the level of 50% cattle slurry application during the period of 2009~2011. The experimental plots were consisted of 5 treatments. Each treatment was triplicates and allocated in the randomized complete block design. For whole crop wheat, annual mean dry matter (DM) yield was significantly (P<0.05) higher for fertilizer application treatments than for no fertilizer treatment, and crude protein (CP) yield was significantly (P<0.05) higher for forage pea and hairy vetch-mixed sowing treatments than for no fertilizer and organic ferilizer treatments. Mean CP, total digestible nutrients (TDN) and relative feed value (RFV) contents of legumes-mixed sowing treatments was significantly (P<0.05) higher than those of other treatments. As diets replaced with 70% whole crop wheat were provided for 450kg of Hanwoo heifers, legumes-mixed sowing treatments could raise more heifers than organic fertilizer and no fertilizer treatments. For triticale, annual mean DM, CP and TDN yields were significantly (P<0.05) higher for fertilizer application treatments than for no fertilizer treatment, and CP content of legumes-mixed sowing and cattle slurry application treatments was significantly (P<0.05) higher than that of other treatments. When 450kg of Hanwoo heifers were fed on diets replaced with 70% triticale, it was estimated that legumes-mixed sowing treatments at the level of 50% cattle slurry application could rear average 3.3~3.4 heads/ha/year, which was significantly (P<0.05) higher than no fertilizer treatment (2.5 heads/ha/year). It was indicated that DM yields of whole crop wheat and triticale were much more effective in cattle slurry application than organic fertilizer, and Legumes-mixed sowing at the level of 50% cattle slurry application rather than whole crop wheat or triticale alone increased yields per unit area and nutritional value such as CP content. In conclusion, it is conceived that whole crop wheat or triticale produced in the manner above can be used instead of grains imported as dietary protein sources in the organic Hanwoo feeding regimen.

Studies on the Estimation of the Genetic Parameters on All Traits in Korean Native Ogol Fowl III Estimations of the Heritabilities and Genetic Correlations on the Egg Shape Index and Egg Qualities (한국재래오골계의 제형질에 대한 유전모수추정에 관한 연구 III, 난형지수 및 난질에 대한 유전력 및 유전상관추구)

  • 한성욱;상병찬;김홍기;백승봉
    • Korean Journal of Poultry Science
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    • v.17 no.2
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    • pp.71-78
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    • 1990
  • This study was conducted to estimate heritabilities and genetic correlations on egg shape index and egg qualities in Korean Native Ogol fowl. The date analysis were a total of 58,320 eggs in 450 pullets bred from 150 dams and 20 sires of korean Native Ogol fowl raised at Chungnam National University from June 18, 1987 to April 6, 1989. The results obtained are summarized as follows:1. On the egg shape index and egg qualities, the egg shape index at first egg, 300 and 500 days of age were 75.044, 74.169 and 72.601 ; the shell thickness were 0.342, 0.320 and 0.326 mm: the albumen height were 6.014, 5.161 and 4.807mm:the Haugh units were 83.903, 71.348 and 71.136, respectively. 2. The heritabilities estimates of egg shape index and egg qualifies based on the varience of sires, dams and combined components were 0.120-0.827, 0.485-0.503 and 0.232-0.872 for egg shape index at first egg, 300 days and 500 days of age: 0.197-0.819. 0.184-0.756 and 0.279-0.557 for shell thickness at first egg, 300days and 500days of age:0.202-0.678, 0.119-0.394 and 0.225-0.527 for albumen height at first egg, 300 and 500 days of age 0.108-0.669, 0.237-0.251 and 0.354-0.443 for Haugh units at first egg 300days and 500days of age. 3. The genetic correlation coefficients of egg shape index and egg qualifies were as follows; between egg shape index and shell thickness, albumen height and Haugh units were 0.596-0.909, 0.384-0.943 and 0.121-0.619:between shell thickness and albumen height. Haugh units were 0.082-0.596, -0.076-0.167:between albumen height and Haugh units were 0.374-0.964.

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Estimation of Change in Soil Carbon Stock of Pinus densiflora Forests in Korea using KFSC Model under RCP 8.5 Climate Change Scenario (한국형 산림토양탄소모델(KFSC Model)을 이용한 RCP 8.5 기후변화 시나리오 하에서의 국내 소나무림 토양탄소 저장량 장기 변화 추정 연구)

  • Park, Chan-woo;Lee, Jongyeol;Yi, Myongjong;Kim, Choonsig;Park, Gwan Soo;Kim, Rae Hyun;Lee, Kyeong Hak;Son, Yowhan
    • Journal of Climate Change Research
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    • v.4 no.2
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    • pp.77-93
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    • 2013
  • Global warming accelerates both carbon (C) input through increased forest productivity and heterotrophic C emission in forest soils, and a future trend in soil C dynamics is uncertain. In this study, the Korean forest soil carbon model (KFSC model) was applied to 1,467,458 ha of Pinus densiflora forests in Korea to predict future C dynamics under RCP 8.5 climate change scenario (RCP scenario). Korea was divided into 16 administrative regions, and P. densiflora forests in each region were classified into six classes by their stand ages : 1 to 10 (I), 11 to 20 (II), 21 to 30 (III), 31 to 40 (IV), 41 to 50 (V), and 51 to 80-year-old (VI+). The forest of each stand age class in a region was treated as a simulation unit, then future net primary production (NPP), soil respiration (SR) and forest soil C stock of each simulation unit were predicted from the 2012 to 2100 under RCP scenario and constant temperature scenario (CT scenario). As a result, NPP decreased in the initial stage of simulation then increased while SR increased in the initial stage of simulation then decreased in both scenarios. The mean NPP and SR under RCP scenario was 20.2% and 20.0% higher than that under CT scenario, respectively. When the initial age class was I, IV, V or VI+, predicted soil C stock under CT scenario was higher than that under RCP scenario, however, the countertrend was observed when the initial age class was II or III. Also, forests having a lower site index showed a lower soil C stock. It suggested that the impact of temperature on NPP was higher when the forests grow faster. Soil C stock under RCP scenario decreased at the end of simulation, and it might be derived from exponentially increased SR under the higher temperature condition. Thus, the difference in soil C stock under two scenarios will be much larger in the further future.

Estimation of Secondary Scattered Dose from Intensity-modulated Radiotherapy for Liver Cancer Cases (간암환자에 대한 세기조절방사선치료에서의 2차 산란선량평가)

  • Kim, Dong Wook;Sung, Jiwon;Lee, Hyunho;Yoon, Myonggeun;Chung, Weon Kuu;Bae, Sun Hyun;Shin, Dong Oh;Chung, Kwangzoo;Lim, Young Kyung;Shin, Donho;Lee, Se Byeong
    • Progress in Medical Physics
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    • v.24 no.4
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    • pp.295-302
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    • 2013
  • We estimated secondary scattered and leakage doses for intensity-modulated radiotherapy (IMRT), volumetric arc therapy (VMAT) and tomotherapy (TOMO) in patients with liver cancer. Five liver patients were planned by IMRT, VMAT and TOMO. Secondary scatter (and leakage) dose and organ equivalent doses (OEDs) are measured and estimated at various points 20 to 80 cm from the iso-center by using radiophotoluminescence glass dosimeter (RPLGD). The secondary dose per Gy from IMRT, VMAT and TOMO for liver cancer, measured 20 to 80 cm from the iso-center, are 0.01~3.13, 0.03~2.34 and 0.04~1.29 cGy, respectively. The mean values of relative OED of secondary dose of VMAT and TOMO for five patients, which is normalized by IMRT, measured as 75.24% and 50.92% for thyroid, 75.14% and 40.61% for bowel, 72.30% and 47.77% for rectum, 76.21% and 49.93% for prostate. The secondary dose and OED from TOMO is relatively low to those from IMRT and VMAT. OED based estimation suggests that the secondary cancer risk from TOMO is less than or comparable to the risks from conventional IMRT and VMAT.

Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2014 (설비공학 분야의 최근 연구 동향: 2014년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.7
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    • pp.380-394
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    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

Developing a Traffic Accident Prediction Model for Freeways (고속도로 본선에서의 교통사고 예측모형 개발)

  • Mun, Sung-Ra;Lee, Young-Ihn;Lee, Soo-Beom
    • Journal of Korean Society of Transportation
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    • v.30 no.2
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    • pp.101-116
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    • 2012
  • Accident prediction models have been utilized to predict accident possibilities in existing or projected freeways and to evaluate programs or policies for improving safety. In this study, a traffic accident prediction model for freeways was developed for the above purposes. When selecting variables for the model, the highest priority was on the ease of both collecting data and applying them into the model. The dependent variable was set as the number of total accidents and the number of accidents including casualties in the unit of IC(or JCT). As a result, two models were developed; the overall accident model and the casualty-related accident model. The error structure adjusted to each model was the negative binomial distribution and the Poisson distribution, respectively. Among the two models, a more appropriate model was selected by statistical estimation. Major nine national freeways were selected and five-year dada of 2003~2007 were utilized. Explanatory variables should take on either a predictable value such as traffic volumes or a fixed value with respect to geometric conditions. As a result of the Maximum Likelihood estimation, significant variables of the overall accident model were found to be the link length between ICs(or JCTs), the daily volumes(AADT), and the ratio of bus volume to the number of curved segments between ICs(or JCTs). For the casualty-related accident model, the link length between ICs(or JCTs), the daily volumes(AADT), and the ratio of bus volumes had a significant impact on the accident. The likelihood ratio test was conducted to verify the spatial and temporal transferability for estimated parameters of each model. It was found that the overall accident model could be transferred only to the road with four or more than six lanes. On the other hand, the casualty-related accident model was transferrable to every road and every time period. In conclusion, the model developed in this study was able to be extended to various applications to establish future plans and evaluate policies.