PURPOSES : The purpose of this study was to develop the evaluation methodologies for spraying amount and sprayed condition of curing compound based on IoT technology when concrete pavements are constructed. METHODS : To measure the spraying amount of curing compound, a turbine type flowmeter was selected and a number of laboratory experiments were performed to verify the applicability of the selected sensor. To evaluate the uniformity of the sprayed curing compound on the concrete pavement surface, image process technologies were examined using pictures taken from the actual construction sites and from the test specimens. RESULTS : By performing experiments using water and curing compound, the selected flowmeter was verified to properly be applied to measure the spraying amount of curing compound with an acceptable accuracy. By conducting image processing using pictures of the sprayed curing compound on the concrete pavement surface, it was found that the 8 color analysis method was the best to evaluate the uniformity of the sprayed curing compound. CONCLUSIONS : From this study, it was concluded that the spraying amount of curing compound could be accurately measured using a turbine type flowmeter and the uniformity of the sprayed curing compound on the concrete pavement surface could be properly evaluated using an image processing technology.

PURPOSES : Korea Expressway Corporation has been working on an early remodeling project for the Jungbu Expressway to prepare methods for the rehabilitation of the old CRCP(Continuous Reinforced Concrete Pavement). In this study, the distress of the old CRCP was classified, and the engineering properties of the core specimens for each failure type were evaluated. Based on the test results, the concrete conditions of the existing CRCP were evaluated. This provides a basis for the pre-treatment or repair of the existing CRCP in the JungBu Expressway. METHODS : To evaluate the pavement condition of the Jungbu Expressway, existing PMS(Pavement Management System) data were analyzed, and field surveys were conducted for each pavement condition. The longitudinal rebar depth, rebar spacing, horizontal crack, and pavement thickness were examined through core sampling and non-destructive testing. In addition, the core specimens were used to evaluate the compressive strength, chloride penetration test, chloride ion penetration resistance, and freeze-thaw resistance. RESULTS : From the analysis of existing PMS data, field surveys, and laboratory tests, it was found that the old CRCP condition of the Jungbu Expressway was not good. Various types of failures occurred, and horizontal cracks at the rebar location, upward rebar locations, and rebar corrosion were confirmed. In addition, the compressive strength was considerably high, but the durability-related index was judged to be poor. CONCLUSIONS : For the remodeling project of the Jungbu Expressway, appropriate repairs should be carried out for each type of distress in the old CRCP.

PURPOSES : The purpose of this study is to enhance the reliability of artificial intelligence for a noise-based pavement condition rating system (to a target performance of 95 %). METHODS : By comparing four types of pattern recognition artificial intelligence, this work acquires high-quality learning data and optimizes data learning through analysis of error characteristics. RESULTS : The system reliability improved up to 97 % (82 % in a prior study). In addition, 100 % was achieved for the E(F) condition grade, which has a direct impact on maintenance decision making. CONCLUSIONS : KNN-DTW (K-nearest neighbor dynamic time warping) is judged to be the most suitable type of artificial intelligence for a noise-based pavement condition rating system; a 4-grade system is the most suitable for classifying pavement condition.

This study was conducted to evaluate the overall dietary habits and nutritional status of 294 elementary school students located in Gwangju using the NUTRILITE nutrition quotient (NQ). The NQ score of the subjects was 59.5 out of 100, which corresponds to the level requiring “monitoring”. Compared to the 64.4 score of students in the 5th and 6th grades of six metropolitan cities, the scores of the present subjects were lower. The NQ components were 57.4 for balance factors, 52.4 for moderation factors, 55.0 for diversification factors, 57.6 for practice factors, and 80.1 for environmental factors. Regarding the characteristics according to the NQ level, the score (61.5 in 7 times/wk vs. 55.3 in 1-2 or none times/wk) tended to be higher in subjects who frequently eat with their families (p<0.001). In conclusion, nutrition education should be provided to students to increase the frequency of meals with their families, to develop a habit of exercising regularly, and reduce the consumption of ramen, cookies, and processed drinks that are frequently consumed. These results can be used as basic data to develop nutrition education programs to improve the dietary habits and nutritional status of students in Gwangju.

본 연구에서는 방사선 촬영 기법을 사용하여 국내에 서식 하는 무미양서류인 청개구리 (Hyla japonica), 옴개구리 (Glandirana rugosa), 참개구리 (Pelophylax nigromaculatus), 황소개구리 (Lithobates catesbeianus)의 체성분과 골밀도를 분석하였다. 이중 엑스선 촬영 장치 (Dual-energy Xray absorptiometry)를 사용하여 체성분과 골밀도를 측정하 였으며 암수 간 차이와 종 간 차이를 파악하였다. 또한 방사선 촬영 기법을 사용한 신체 상태 평가 방법의 효용성을 확인하기 위해 무미양서류 4종의 먹이자원 가용성을 파악하고 신체상태와의 관계를 확인하였다. 신체를 구성하는 성분인 골, 지방, 제지방 비율과 골밀도는 암수 간 차이가 없었지만 무미양서류 4종 간 차이는 있었다. 골밀도와 먹이자원 가용성은 황소개구리가 가장 높았으며 청개구리가 가장 낮았다. 옴개구리와 참개구리의 먹이자원 가용성은 차이는 없었다. 골밀도와 먹이자원 가용성은 유의미한 상관관계를 가졌으며 먹이 상태를 나타내는 질소 안정동위원소비는 골밀도에 의해서만 변화하는 것을 확인하였다. 기회적 포식자인 무미양서류의 먹이 상태 혹은 자원 가용성이 체성분은 물론 골밀도에 영향을 미칠 수 있다. 개체의 신체 상태를 나타내는 체성분과 골밀도는 무미양서류에서 서식지의 안정성을 평가하는 생태지표로서 사용이 가능할 것으로 보인다.

PURPOSES : This paper is aimed at suggesting a novel approach for determining the pavement condition rating based on the tire-surface friction noise using a machine learning algorithm as a low-end pavement condition monitoring system. METHODS : Vehicle on-board type noise measurement system according to the ISO11819-2, and the K-nearest neighbors with dynamic time warping algorithm were applied. The system and algorithm were empirically tested with a field study. RESULTS : The developed AI- and noise-based pavement condition monitoring system demonstrated significantly positive results with a precision 90.8%, recall 84.8%, and f1-score 86.1%. CONCLUSIONS: We herein confirmed that the acoustic property between the tire and road surface can be used for monitoring pavement conditions. It is believed this finding presented a new paradigm for monitoring pavement conditions based on visual information. However, extensive studies focused on the practical application of this method are required.

PURPOSES: The objective of this study is to evaluate and compare the stiffness characteristics and seasonal variation in surface deflections of block and asphalt pavements using the light weight deflectometer (LWD) and falling weight deflectometer (FWD). METHODS: LWD and FWD testing was conducted on block and asphalt pavement sections in a low-impact development facility, to evaluate the structural capacity and seasonal variation in asphalt pavements. To analyze the seasonal variation in stiffness characteristics, this testing was performed in October 2016, January 2017, and March 2017 in the same drop locations. RESULTS : It was found from that the average center deflections in the asphalt and block pavements were 218 ㎛ and 2974 ㎛, respectively. The center deflections measured using FWD testing in block pavement are 15 times those measured in asphalt pavement. It was also observed that LWD deflections in block pavements were decreased by approximately 65-90% as the air temperature dropped from 20 to 4℃. The degree of reduction in block pavement was significantly higher when compared with asphalt pavement, which showed a 25- 50% reduction in deflection. CONCLUSIONS: When using block pavements for roadways, the structural capacity of the pavement system should be considered during the design and construction stages. In block pavements, the use of low-quality material and insufficient compaction in the base and subgrade layers can induce a reduction in structural capacity, which would lead to the need for frequent repair work. A reinforcement underneath the block layer would be an appropriate measure for improving the structural support and extending the service life.

Underground cavities are frequently taking place in urban areas due to soil loss caused by structural defects of underground buried pipes. In this study, a field experimental program was conducted to detect ground condition using the electrical resistivity survey and the pneumatic cone penetration test. In addition, we proposed a method to estimate the weighted mean resistivity value by quantifying the electrical resistivity measurements through image analysis in order to compare the results of pneumatic cone penetration test. Consequently, it was found that as the weighted average resistivity value decreased, the smaller the N-value (penetration depth per blow number) from the pneumatic cone penetration test results. Based on the limited number of field experimental measurements, the correlation between weighted average resistivity value and the N-value of pneumatic cone penetration test is deemed promising in assessment of ground conditions associated with developing underground cavitation.

Due to the sewer induced ground subsidence, there is an increasing demand for the advanced visual inspection technique for the existing sewer pipe structures. This study aim to develop a new condition assessment method using visual inspection device with automatic crack extracting and real-time gas monitoring systems for large diameter glass-fiber reinforced plastic sewer pipes. In this paper, a high-precision image capturing system that automatically extracts cracks in the large-diameter sewer pipes and sewage culverts with a diameter of 1,000 mm or more, and a real-time gas detection sensor for investigator safety were considered. By analyzing the module technology of the visual inspection device, the test device and their software for system integration were developed. It is expected that the developed technique inspecting conditions of the GFRP sewer pipes using the proposed visual inspection device in this study can be effectively used for various types of underground structures in the future.

The purpose of this study is to examine the feeding and nutritional status of enteral tube-fed elderly patients. Subjects included 77 elderly hospitalized patients who had received enteral nutrition more than one week before admission. Medical records on admission and actual feeding volume were used to assess anthropometric, biochemical, and nutritional status. Most patients manifested disorders of the nervous system (93.5%) and the average duration of tube feeding was 13.9 months. The average feeding volume of formula was 1,107 mL per day and the mean ratios of calorie and protein (supplied vs. required) were 81.7% and 80.9%, respectively. At admission, 57.4% of the patients were malnourished according to the institutional criteria. Patients receiving less than 80% of the required calories were in worse nutritional status compared with those receiving more than 80% of the required calories. Body mass index, percent ideal body weight, serum albumin level and blood lipid levels (total cholesterol, HDL-cholesterol, triglyceride) were significantly lower in patients receiving less than 80% of the required calories. These results indicate the high prevalence of malnutrition and the need for increased attention and nutritional care of elderly patients undergoing long-term enteral nutrition.

The objective of the this study was to identify the potential relationship between eating breakfast together as a family and the nutritional status among Korean adolescents based on the 2013~2015 Korean National Health and Nutritional Examination Survey data. This study investigated 1,300 adolescents ranging in agee from twelve to eighteen years-old. In this study, according to their eating breakfast together as a family or skipping breakfast, we classified the subjects into the eating breakfast together as a family (EBF group) (male=379, female=295), eating breakfast alone (EBA group) (male=177, female=169) and skipping breakfast (SB group) (male=152, female=128). Both male and female, age in the EBF group was lower than those of the EBA and SB group (p<0.0001, respectively). In the male, the EBF group exhibited significantly higher fiber (p=0.0168) and potassium density (p=0.0065) and lower beverage intake (% energy) (p=0.0040) than the EBA and SB groups. No difference was observed the proportion of subjects who practiced a healthy diet between three groups, however, the EBF and EBA groups had a smaller proportion of subjects who were in a condition of hypo-nutrition compared to the SB group (p<0.0001, respectively). The present findings suggest that the practice of eating breakfast together as a family in adolescents may bean important consideration in relation to micro-nutrient intake status.