High-entropy alloys (HEAs) are attracting attention because of their excellent properties and functions; however, they are relatively expensive compared with commercial alloys. Therefore, various efforts have been made to reduce the cost of raw materials. In this study, MIM is attempted using coarse equiatomic CoCrFeMnNi HEA powders. The mixing ratio (powder:binder) for HEA feedstock preparation is explored using torque rheometer. The block-shaped green parts are fabricated through a metal injection molding process using feedstock. The thermal debinding conditions are explored by thermogravimetric analysis, and solvent and thermal debinding are performed. It is densified under various sintering conditions considering the melting point of the HEA. The final product, which contains a small amount of non-FCC phase, is manufactured at a sintering temperature of 1250oC.

PURPOSES : In this study, the factors affecting the severity of traffic accidents in highway tunnel sections were analyzed. The main lines of the highway and tunnel sections were compared, and factors affecting the severity of accidents were derived for each tunnel section, such as the tunnel access zone and tunnel inner zone. METHODS : An ordered probit model (OPM) was employed to estimate the factors affecting accident severity. The accident grade, which indicates the severity of highway traffic accidents, was set as the dependent variable. In addition, human, environmental, road condition, accident, and tunnel factors were collected and set as independent variables of the model. Marginal effects were examined to analyze how the derived influential factors affected the severity of each accident. RESULTS : As a result of the OPM analysis, accident factors were found to be influential in increasing the seriousness of the accident in all sections. Environmental factors, road conditions, and accident factors were identified as the main influential factors in the tunnel access zone. In contrast, accident and tunnel factors in the tunnel inner zone were found to be the influencing factors. In particular, it was found that serious accidents (A, B) occurred in all sections when a rollover accident occurred. CONCLUSIONS : This study confirmed that the influencing factors and the probability of accident occurrence differed between the tunnel access zone and inner zone. Most importantly, when the vehicle was overturned after the accident occurred, the results of the influencing factors were different. Therefore, the results can be used as a reference for establishing safety management strategies for tunnels or underground roads.

PURPOSES : It is necessary to implement traffic-control strategies for underground roads. In this study, the application criteria for traffic control were developed to minimize actual traffic congestion on underground roads before it occurs. In particular, the traffic congestion judgement criteria and procedure (TJCAP) were developed. They can specifically classify the possibility of traffic congestion underground. METHODS : A microscopic traffic simulation model was used to analyze different scenarios. With the scenario simulation results, a hierarchical clustering analysis was applied to produce quantitative values from the TJCAP for each experimental network case. RESULTS : For network case (a), it was concluded that the possibility of traffic congestion on underground roads increases when the speed of the ground road connected to the main underground road and the connected ground road after the outflow of the ramp section is low. When the connected road is an interrupted facility after entering the underground roads, the red time is long, and when the section travel speed is 15 km/h, the possibility of traffic congestion underground is highest. A cluster analysis based on these results was performed using two techniques (elbow and silhouette) to verify the final classification. CONCLUSIONS : The TJCAP were designed to operate traffic flow with stricter criteria than traffic congestion management on ground roads. This reflects the difference in the driving environment between underground and above-ground roadways.

PURPOSES: This study presents the results of the collection rate of various road debris dummies using Automated Road Debris Remover System(ROBOS), which is a newly developed automatic road-debris removal system. In addition, for traffic flow safety, appropriate safe deceleration distances for ROBOS are estimated using VISSIM. METHODS: A total of 12 kinds of road debris dummies were selected based on the opinions of public agencies, and randomly placed on the road. Repeated tests were performed. The road debris dummies were placed on the center of the lane, the shoulders, and the median. During the test, the ROBOS running speed was maintained at 15 km/h for an approximately 10-km-long roadway, and the collection and loading process was performed five times under the same condition. For the simulations, the road debris was assumed to be placed on Lane 1 under different traffic conditions and grades. Multiple simulations were conducted, and the average values were used to obtain appropriate safe deceleration distances for ROBOS. RESULTS: The dummies were considerably large and heavy, and the collection rate was very high for the very light dummy. The simulation results indicate that during debris collection using ROBOS, when the traffic volume is relatively low, the degree of change in traffic flow is high, and when the traffic flow rate is high, the risk of an accident is also considerable. CONCLUSIONS : We demonstrated that the debris collection efficiency of ROBOS is very high when the brush-conveyor and vacuum are used simultaneously. Further, when the exact location of road debris on specific lanes and for specific traffic volumes is known, a safe deceleration distance is recommended.

PURPOSES: The purpose of this study is to identify the key factors that influence a driver’s trust in road-freezing risk information METHODS : A survey was designed and conducted in the metropolitan area to analyze drivers’perception towards road-freezing risk information. A binary logistic regression model was developed based on the survey responses. The statistically significant model coefficients were determined and their odds ratios were calculated. Finally, they were considered as the key factors influencing drivers’trust in roadfreezing risk information. RESULTS : The developed binary logistic regression model was validated through statistical tests. The final results indicated that previous experiences of accidents on slippery roads, as well as route choice patterns are statistically significant, having 95% confidence levels. CONCLUSIONS : Previous experiences of accidents on slippery roads and road choice patterns are the factors that most significantly influence drivers’trust in road-freezing risk information. The findings of this study will be used as fundamental data in establishing tailored road-freezing risk mitigation procedures and services.

PURPOSES: This study aimed to evaluate the performance of a model developed for road surface temperature change pattern in reflecting specific road characteristics. Three types of road sections were considered, namely, basic, tunnel, and soundproof tunnel. METHODS: A thermal mapping system was employed to collect actual road surface temperature and locational data of the survey vehicle. Data collection was conducted 12 times from 05:30 am to 06:30 am on the test route, which is an uninterrupted flow facility. A total of 9010 road surface temperature data were collected, and half of these were selected based on a random selection process. The other half was used to evaluate the performance of the model. The model used herein is based on machine learning algorithms. The mean absolute error (MAE) was used to evaluate the accuracy of the estimation performance of the model. RESULTS: The MAE was calculated to determine the difference between the estimated and the actual road surface temperature. A MAE of 0.48℃ was generated for the overall test route. The basic section obtained the smallest error whereas that of the tunnel was relatively high. CONCLUSIONS: The road surface temperature change is closely related to the air temperature. The process of data pre-processing is very important to improve the estimation accuracy of the model. Lastly, it was difficult to determine the influence of the data collection date on the estimation of the road surface temperature change pattern due to the same weather conditions.

PURPOSES: This study evaluates the reliability of the patterns of changes in the road surface temperature during winter using a statistical technique. In addition, a flexible road segmentation method is developed based on the collected road surface temperature data. METHODS: To collect and analyze the data, a thermal mapping system that could be attached to a survey vehicle along with various other sensors was employed. We first selected the test route based on the date and the weather and topographical conditions, since these factors affect the patterns of changes in the road surface temperature. Each route was surveyed a total of 10 times on a round-trip basis at the same times (5 AM to 6 AM). A correlation analysis was performed to identify whether the weather conditions reported for the survey dates were consistent with the actual conditions. In addition, we developed a method for dividing the road into sections based on the consecutive changes in the road surface temperature for use in future applications. Specifically, in this method, the road surface temperature data collected using the thermal mapping system was compared continuously with the average values for the various road sections, and the road was divided into sections based on the temperature. RESULTS : The results showed that the comparison of the reported and actual weather conditions and the standard deviation in the observed road surface temperatures could produce a good indicator of the reliability of the patterns of the changes in the road surface temperature. CONCLUSIONS: This research shows how road surface temperature data can be evaluated using a statistical technique. It also confirms that roads should be segmented based on the changes in the temperature and not using a uniform segmentation method.

Background : The practice of keeping the medicinal herbs at room temperature causes many problems, but due to lack of sufficient field research and study, it is difficult to improve related regulations and safety management. Methods and Results : The Cnidium Rhizome and Angelica gigas Root were inoculated with Lasioderma serricorne F. and incubated at 28℃ for 2.5 months and 5 months. After five months, the number of Lasioderma serricorne F. in Cnidium Rhizome increased from 30 to 1,429 (about 47 times). In the same period, the number of insects in Angelica gigas Root increased from 30 to 663 (about 22 times). Due to the rapid increase in pest population, hygiene deteriorated, changes in the active ingredient and appearance quality of the herbal medicines, which greatly damaged the value of the herbal medicine. Conclusions : These results show that current regulation requiring only sealing and not specifying the storage temperature do not guarantee quality safety. Therefore, it is necessary to establish appropriate preservation standards and improve management regulations in order to preserve safety.

Background : Angelica dahurica Bentham et Hooker, Angelica gigas Nakai, Ostericum koreanum Maximowicz and Peucedanum japonicum Thumberg　are a major medicinal plant in north Geungbuk province. Using medicinal plants are impotant it`s ingredient. Dry condition and stroage method are not standard manual. The ingredient variation of dry condition and stroage method were not researched. Methods and Results : Using plant material were cutivated on Gyongsangbukdo Bonghwa area. It were studied ingredient variation after dry and storage condition by HPLC methods. Major ingredient of Angelica gigas Nakai are decurusin, decurusinangelate. Heated air bulk dry get more decursin than natuarl dry and decurusinangelate of natural bulk dry was higher than heated air bulk dry. Major ingredient of Ostericum koreanum Maximowicz are imperatorin and isoimperatorin.. Imperatorin of Ostericum koreanum was highest peak on 50℃ heated-air dry after plastic bag sorage and isoimperatorin was highest peak on 40℃ heated-air dry after mountain cultivation. Imperatorin is a major ingredient Angelica dahurica Bentham et Hooker. Heated air bulk dry get more decursin and decursinangelate than natuarl dry and small heated-air dry. Peucedanol-7o_glucoside is a major ingredient Peucedanum japonicum Thumberg. Natural bulk dry get more peucedanol-7o_glucoside than heated-air bulk dry. Conclusion : Ingredient of Angelica dahurica Bentham et Hooker, Angelica gigas Nakai, Ostericum koreanum Maximowicz are different under various cutivation, drying method, storage. Diffent Ingedients of Angelica gigas Nakai, Ostericum koreanum Maximowicz were not accord it’s optical conditon.

Background : Schisandra chinensis is being weighted difficulties in stable production, there is increasing drought damage caused by climate change as shallow rooted crops. Therefore, the study was performed for water supply capacity and growth characteristics analysis by setting the irrigation method for the drought damage reduction. Methods and Results : Test material was used sophomore V-shaped planting Schisandra chinensis. Irrigation method were surface watering, underground watering, sprinkler and untreated. Underground irrigation was irrigation that buried hose and then dug up the 15㎝. Soil moisture tension was the irrigation after fixed at -30 ㎪(23%). Irrigation timing was performed in June-July that high drought damage and made the most fruit enlargement. The main investigating items were investigated fruit growth, normal fault rate, soil moisture and EC content according to the irrigation method. Normal fruit rate according to irrigation method were appeared in sprinkler(81, 74 %)>underground irrigation(76, 69 %)>surface irrigation(76, 67%)>untreated(66, 52 %). Cluster length of yield component was determined to effective irrigation method in fruit growth the highest in sprinkler. Soil moisture contents was maintained at appropriate level with significant -30㎪(23 %) in the sprinkler. EC content low with a downward trend in underground irrigation and sprinkler. Water supply capacity according to Irrigation Method were sprinkler 40 tons, underground irrigation 85 tons, surface irrigation 138 tons. Conclusion : Appropriate watering methods for drought damage reduction of Schisandra chinensis caused by climate change was determined in the most efficient irrigation method in sprinkler that high fruit growth and normal fruit rate, lower the required of water supply capacity.

Background : Aralia cordata and Polygonum multiflorum GAP cultivation requires a stable drying and storage settings after harvesting. therefore, this experiment was performed in order to effectively manage the physical, chemical and biological hazards. Methods and Results : Test materials were used biennial Aralia cordata, Polygonum multiflorum harvested from the medicinal testing ground. The drying temperatures were treated with 40, 50, 6 0℃ and natural drying. Storage containers were stored in plastic boxes, styrofoam boxes and kraft paper containers, examined the color and quality changes for eight months. Aralia cordata and Polygonum multiflorum drying temperature is dry it took natural drying 720 hours, 40℃ hot air drying 180 hours, 50℃ hot air drying 168 hours and 60℃ hot air drying 108 hours. However, the difference chromaticity of the Lab value corresponding to the temperature does not appear, it was good to dry in a short time at 60℃. Aralia cordata and Polygonum multiflorum stored in a styrofoam box storage method but can be stored at room temperature for up to four months, began to decay caused by moisture content it continues to increase. In plastic box in case of Aralia cordata and kraft vessel in case of Polygonum multiflorum can be stored for eight months in room temperature without decay. Styrofoam boxes stored at 5℃ cold storage were higher water absorption such as room temperature, but decay did not occur. Plastic box and styrofoam box were a tendency such as room temperature. Conclusion : Aralia cordata and Polygonum multiflorum are thought that the color change is not large depending on the drying temperature the lower the water content. Styrofoam storage box, the air permeability is higher than plastic boxes and containers Kraft vessel, decay occurs expected increase.