In this study, the characteristics and taste components of six different oyster mushroom cultivars (Gonji-7ho, Santari, Baekseon, Chunchu, Suhan, and Heuktari) were analyzed and compared. The Heuktari mushroom pileus had the lowest brightness index (32.8) and remained dark (brightness index: 30.5) even after blanching. The moisture content of the mushrooms was approximately 90%. The salinity and sugar contents were highest in Heuktari (5.7% and 7.1%, respectively). Gonji -7ho had the highest contraction rates, with a length contraction rate of 16.4% and thickness contraction rate of 23.9%. The total amino acid content was highest in Heuktari (537.8 mg/100 g), but the glutamine content contributing to umami taste was highest in Santari (59.4 mg/100 g) and the aspartic acid content was highest in Baekseon (33.1 mg/100 g). Among the 5?-nucleotide components, guanosine monophosphate, which enhances umami taste, was highest in Baekseon (0.7 mg/g). Baekseon was also calculated to have the highest umami taste concentration based on amino acid and nucleic acid contents (12.7 g/100 g). The results of this study serve as valuable basic data on the physicochemical characteristics of oyster mushroom cultivars grown in Korea.

본 연구는 기업의 기술혁신이 고용과 기업성과에 미치는 영향을 변수 간 양방향 인과관계를 고려하여 분석하였다. 기술혁신의 대리변수는 기업의 특허출원 수이며, 분석대상은 100인 이상 규모의 국내 제조업체이다. 실증분석의 경우 기술혁신(특허출원), 고용(근로자 수, 숙련 근로자 비중), 기업성과(근로자 1인당 매출액)가 종속변수인 연립방정식 모형을 3단계 최소자승추정법(3SLS)으로 추정하였다. 외생변수로 기업의 경영상 특성과 일반적 특성을 통제하였고, 각 방정식의 식별변수로 R&D집약도, 근로자 1인당 노동비용(또는 기업부설연구소 보유 여부), 교육훈련투자를 사용하였다. 분석자료는 인적자본기업패널(HCCP)의 1차년도(2005년) ∼7차년도(2017년) 자료이며, 이를 NICE신용평가정보(주)의 기업 재무자료 및 한국 특허청의 특허정보와 병합하여 사용하였다. 분석결과에 의하면, 기업의 특허출원이 활발할수록 근로자 수, 숙련 근로자 비중, 근로자 1인당 매출액이 모두 증가하였고, 반대 방향의 인과관계도 모두 유의 하였다. 따라서 기업의 기술혁신은 고용의 확대 및 질적 제고뿐 아니라 기업의 지속적인 성장에도 기여하는 것으로 확인된다.

This study would analyze a survey conducted with 609 workers to use the results as materials for the settlement of safety culture for the characteristics of the establishment by assessing the status of the workers’ exposure to harmful risks and the impact on safety culture to present the following conclusions. This study has significance in that it found that exposure to harmful/dangerous factors in the establishment and the workers’ experiences of occupational accidents affect their perception of safety culture and that in particular, ‘worker safety priority’ of the safety cultural factors was an important factor, and it is judged that continuous studies are necessary so that the perceptions of safety culture will spread in the establishment.

PURPOSES : The purpose of this study was to improve the performance of concrete pavements by measuring the unit-water content with an Internet-of-Things (IoT)-based unit-water content measurement device at an increased precision compared with that of existing measuring equipment. METHODS : We calculated the properties of concrete that varied according to variations in the unit-water content. To confirm the change in the performance of concrete pavements, we compared and analyzed the fatigue cracking rate and international roughness index of concrete pavements at the 20-year point of public use according to the changes in properties using the Korea Pavement Research Program(KPRP). RESULTS : We confirmed that IoT-based measurement equipment can improve the performance of pavements without changing their mixing designs or specifications. We confirmed that the performance of the concrete pavements changed significantly, even with unit-water content variations within the range of quality standards. According to IoT-based unit-water content management, we confirmed that the performance of the concrete pavement (fatigue cracking rate and international roughness index) improved without changing the mixing design. CONCLUSIONS : We confirmed that by using IoT-based unit-water content management, pavement performance can be improved. It is necessary to consider whether the application of this concept to other concrete property management items, such as the chloride content, is possible. Considering the changes in concrete properties according to the unit-water content based on laboratory tests and considerations of various load conditions will be necessary for future research.

PURPOSES : This study was conducted to compare and evaluate the compaction performance and physical properties of recycled asphalt mixtures by utilizing the characteristics of hot-mix asphalt mixtures and foamed asphalt. METHODS : A wearing-course mixture was used for performance evaluations. Subsequently, dynamic shear rheometry (DSR), compaction performance, general physical properties, tensile strength ratio, and Hamburg wheel tracking were tested. RESULTS : As a result of performance comparisons, compaction, and general physical properties satisfied the quality standards. In the Hamburg wheel tracking test, the mixture with the antistripping agent improved performance by approximately 40% compared with the general mixture. As the foamed asphalt binder was produced at a relatively low temperature compared with the general hot-mix asphalt binder, the penetration, viscosity, and DSR test results of the aged foamed asphalt binder showed that the aging of the asphalt binder was suppressed, and the flexibility increased. Therefore, the resistance to fatigue cracks is expected to be enhanced. CONCLUSIONS : Even though the foamed warm-mix recycled asphalt mixture was produced at a temperature that was 20~30°C lower than the hot-mix asphalt mixture, its physical properties were similar to those of the hot-mix asphalt mixture; its use is expected to reduce the production of fuel and air pollutants.

이 논문에서는 기존의 조인트 교량을 일체식 교대 교량으로 변경할 경우, 온도하중에 의한 상부구조의 인장에 따른 흉벽의 휨거동을 보강하기 위한 흉벽 FRP 보강공법을 제안하고, 설계 및 유한요소해석을 통해 보강 효과를 검토하였다. FRP 보 강재는 펄트루젼 공정으로 제작하며, 흉벽 전면부에 부착하여 일체식 교대 교량으로 변경할 때, 흉벽에 부족한 인장철근의 역할 을 대체하게 된다. 흉벽 FRP 보강공법의 설계는 ACI Committee 440을 참고하여 수행하였으며, 유한요소해석은 콘크리트, 철근 및 유리섬유와 비닐에스터로 제작한 FRP 보강재의 최대응력을 보강 방법에 따라 비교하였다. 유한요소해석 결과, FRP 보강재는 콘크리트에 발생하는 인장응력을 감소시키는 역할을 하며, 흉벽이 저항할 수 있는 휨모멘트를 증가시킬 수 있는 것으로 나타났 다.

PURPOSES : For most local governments, including that of Gangwon-do, the establishment of an organized pavement management system is insufficient, resulting in problems such as inefficient distribution and use of maintenance budgets for deteriorated road pavements. In this study, we aimed to contribute to the establishment of a more reasonable road maintenance strategy by developing a model for predicting the annual international roughness index (IRI) change for national highway asphalt pavements in Gangwon-do based on big data analysis. METHODS : Data on independent and dependent variables used for model development were collected. The collected data were subjected to exploratory data analysis (EDA) and data preprocessing. Independent variable candidates were selected to reduce multicollinearity through correlation analysis and specific conditions. A final model was selected, and sensitivity analysis was performed. RESULTS : The final model that predicts annual IRI change uses independent variables such as annual temperature range, minimum temperature, freeze-thaw days, IRI, surface distress (SD), and freezing days. The sensitivity analysis confirmed that the annual IRI change was affected in the order of annual temperature range, minimum temperature, freeze-thaw days, IRI, SD, and freezing days. CONCLUSIONS : Road maintenance can be performed rationally by predicting future pavement conditions using the model developed in this study. The accuracy of the prediction model can be improved if additional data, such as material properties and pavement thickness, are obtained in future studies.