본 논문은 슬로싱 상태에 놓인 포화 상태 액체수소탱크에서 열 유속 및 BOG(Boil-off gas)의 경향을 다루고 있다. 특히, 액체-기체 간의 침투 및 혼합에 의한 열 교환에 관심을 두었다. 먼저, VOF(Volume of fluid)와 Eulerian 기반의 다상 유동모델로 모형 슬로싱 실험 을 모사하여 압력을 예측하고 계측된 값과 비교하였다. 자유 수면 및 충격 압력 실험 결과와 해석 결과를 비교하였으며, 유체의 속도 예측에서 정확할 수 있음을 간접적으로 증명하였다. 그리고 2차원의 Type-C 원통형 수소탱크를 대상으로 다상열유동해석을 수행하 였다. 이때 포화상태에 놓인 액체 및 기체수소를 가정하고, 해석을 통해 각 상간의 혼합에 의한 열 교환의 수준을 확인하고자 하였다. 단, 상간의 열 교환만을 관심으로 두고 있었으므로 질량전달 및 기화모델은 해석에서 제외하였다. 최종적으로 상의 혼합으로 인해 액 체수소로 유입되는 열 유속의 기여도에 대하여 정리하였다. 또한 액체수소로 유입되는 열 유속과 집중 질량 기반의 간이식을 통해 BOG 발생량 및 경향을 예측하고 분석하였다.

본 연구는 무대재배 복숭아 ‘미황’을 대상으로 성숙기간 중 RGB 영상을 취득한 후 다양한 품질 지표를 측정하고 이를 딥 러닝 기술에 적용하여 복숭아 과실 숙도 분류의 가능성을 탐 색하고자 실시하였다. 취득 영상 730개의 데이터를 training 과 validation에 사용하였고, 170개는 최종 테스트 이미지로 사용하였다. 본 연구에서는 딥러닝을 활용한 성숙도 자동 분 류를 위하여 조사된 품질 지표 중 경도, Hue 값, a*값을 최종 선 발하여 이미지를 수동으로 미성숙(immature), 성숙(mature), 과숙(over mature)으로 분류하였다. 이미지 자동 분류는 CNN (Convolutional Neural Networks, 컨볼루션 신경망) 모델 중 에서 이미지 분류 및 탐지에서 우수한 성능을 보이고 있는 VGG16, GoogLeNet의 InceptionV3 두 종류의 모델을 사용 하여 복숭아 품질 지표 값의 분류 이미지별 성능을 측정하였 다. 딥러닝을 통한 성숙도 이미지 분석 결과, VGG16과 InceptionV3 모델에서 Hue_left 특성이 각각 87.1%, 83.6% 의 성능(F1 기준)을 나타냈고, 그에 비해 Firmness 특성이 각각 72.2%, 76.9%를 나타냈고, Loss율이 각각 54.3%, 62.1% 로 Firmness를 기준으로 한 성숙도 분류는 적용성이 낮음을 확인하였다. 추후에 더 많은 종류의 이미지와 다양한 품질 지 표를 가지고 학습이 진행된다면 이전 연구보다 향상된 정확도 와 세밀한 성숙도 판별이 가능할 것으로 판단되었다.

PURPOSES : In this study, the main factors affecting the severity of traffic accidents among elderly drivers were reviewed, and accident factors with a high accident risk were analyzed. This provided basic data for preparing a traffic safety system for elderly drivers and establishing policies. METHODS : Based on machine learning, the major factors influencing accident severity (from the analysis of traffic accident data for elderly drivers) were analyzed and compared with existing statistical analysis results. The machine learning algorithm used the Scikit-learn library and Python 3.8. A hyperparameter optimization process was performed to improve the safety and accuracy of the model. To establish the optimal state of the model, the hyperparameters were set (K = 5) using K-fold cross-validation. The hyperparameter search applied the most widely utilized grid search method, and the performance evaluation derived the optimal hyperparameter value using neutral squared error indicators. RESULTS : The traffic laws, road sections of traffic accidents, and time zones of accidents were analyzed for accidents involving elderly drivers in Daejeon Metropolitan City, and the importance of the variables was examined. For the analysis, a linear regression model, machine learning-based decision tree, and random forest model were used, and based on the root mean square error, the random forest accuracy performance was found to be the best. Ultimately, 18 variables were analyzed, including traffic violations, accident time zones, and road types. The variables influencing the accident severity were the speed, signal violation, intersection section, late-night driving, and pedestrian protection violation, with the relative importance of the variables in the order of speed (0.3490966), signal violation (0.285967), and late-night driving (0.173108). These can be seen as variables related to the expansion of life damage owing to physical aging and reduced judgment abilities arising from decreases in cognitive function. CONCLUSIONS : Restricting the driving of the elderly on the expressway and at night is reasonable, but specific standards for driving restrictions should be prepared based on individual driving capabilities.

PURPOSES : Presently, it is impossible to evaluate the actual number of operational plans and punctuality of bus routes. In this study, a methodology for separating bus stops and sorting departure orders was developed using city bus operation information, and its field applicability was examined. METHODS : Based on current bus data, the "moving speed (km/h)," "Lag data," and "Lead data" were generated. The number of stops was classified based on the location where the order of the stops changed for each vehicle, and an arbitrary ID was assigned for each number of stops. In the case of a preceding vehicle, for each rotation information, a time interval was calculated based on the same point, and the rotation with the smallest time interval was determined as the preceding vehicle. RESULTS : An evaluation was conducted on Bus Route 201 in Daejeon. The vehicles were classified based on the operation data of the previous day. From analyzing the operation time and distance for each operation based on the last stop and starting point, it was found that both the number of operation plans and performance were consistent. The punctuality was analyzed and was found to be inversely proportional to the difference between the stop arrival time and preset arrival time, preset dispatch interval, and actual dispatch interval. The on-time(regularity) ratio was determined as 98.0% and the early departure ratio was 99.3%, indicating very good regularity. CONCLUSIONS : The research results can be used by local governments with insufficient levels of public transportation-based data management, and can be used as basic data for establishing public transportation policies. The results of this study can be referred to when evaluating the transparency of financial support for public transportation operators and operations, with the aim of enhancing public transportation services.

본 논문은 한·중관계가 크게 경색되는 2016년 사드(THAAD) 배치 이후 양국 지방 정부 간 교류가 어떻게 이루어졌는지 현황과 특징, 문제점을 분석하였다. 분석결과 사드 배치 이후 국가 관계가 크게 경색된 이후에도 양국 지방정부는 신규 교류를 체결하는 등 지속적인 교류 관계를 유지하고 있으며, 코로나19로 교류가 급감한 이후 에도 온라인 방식을 통해 교류를 지속하였다. 그리고 교류의 지속은 경색된 국가 관 계의 개선에 긍정적인 영향을 미칠 수 있다. 그러나 팬데믹 이후 물리적 교류의 감 소, 교류 대상 지방정부의 중첩성 문제, 교류 대상이 특정 지역에 치중되어 있다는 외형적 문제와 더불어 국제교류의 성과가 실질적이고 가시적이지 못하다는 점, 예산 사용에 관한 문제점 등이 한·중 지방정부 교류에 있어 중요한 문제로 지적된다. 지방 정부 국제교류가 국가 관계를 보완한다는 측면에서 향후 교류의 질적 제고를 위해서 이와 같은 문제들이 반드시 개선되어야 한다.

The effect of five different constant temperatures (18, 21, 24, 27, and 30±1°C) and a photoperiod of 14 : 10 (L : D) h on the reproduction parameters of Spodoptera frugiperda was studied. The longevity of adult female S. frugiperda decreased with increasing temperature (22.4 days at 21°C and 13.9 days at 30°C) but not at 18°C. The pre-oviposition period and oviposition period was the shortest at 30°C compared to the other temperatures. The total fecundity egg count was 887.4, 1,246.4, 1,348.9, 1,154.9, and 1,034.2 at 18, 21, 24, 27 and 30°C, respectively, during its life span. The survival rate of female S. frugiperda decreased rapidly after 13 days at 18°C, after 14 days at 21°C, after 15 days at 27°C, and after 9 days at 24°C, and 30°C. On the third day after the start of oviposition, 50% of the total fecundity was accomplished. In corn fields at less than the 10-leaf stage, the distribution of S. frugiperda egg masses was observed in the middle and lower plant regions, corresponding to 46.8% and 41.4% of the total egg masses, respectively. Egg masses were mostly found on the underside of the leaf blade (abaxial) of corn (66.7%). After releasing S. frugiperda adults on May 12, May 17, May 25, and May 30, the number of eggs per egg mass was 89.9, 88.5, 126.6, and 127.9, respectively. Egg masses of the subsequent generations of S. frugiperda were observed from late June, and the number of eggs per egg mass was 155.8 in late June, 270.7 in early July, and 303.5 in mid-July.

The purpose of this study was to breed a variety of stable productivity and high storage characteristics of white Hypsizygus marmoreus, which has high demand at domestic and global market due to a low bitter taste and the preference for white species. Accordingly, ‘Baekmaru’ was bred by hybridizing brown and white cap color species and backcrossing with white species. The ‘Baekmaru’ variety was bred by crossbreeding the brown and white species and backcrossing the white species. Through repeated cultivation of ‘Baekmaru’, a variety with a low contamination rate was selected when culturing the spawn for stable cultivation. As a results of demonstration test, the yield of ‘Baekmaru’ was 14% higher than that of the commercial variety. In addition, among the fruiting body characteristics of ‘Baekmaru’, diameter and thickness of the pileus were 16.43±15.27mm and 6.46±0.58mm, which were slightly higher than the commercial variety, and the hardness was 2.69±0.89N for the pileus and 3.09±0.89N for the stipe. The shelf life showed less change in thickness and color of pileus compared to commercial variety. The hardness of pileus of 'Baekmaru' was maintained in the range of 3.5 to 4.0N in the 4oC and 4oC and 20oC mixed treatment until 30 days of storage, and was higher than that of the commercial variety. Therefore, it was suggested to be excellent in storability.

To develop mushroom varieties for cultivating at low temperature on oak logs, a strain with a low fruiting body generation temperature was crossed with Di-mon to select for a line with excellent properties. Selection was followed by cultivation testing. From these studies, Heunghwa 1ho was identified. The optimum temperature for cultivating Heunghwa 1ho, was 13.3oC. The fruiting temperature range was 6.4~20.2oC, identical to that of the parent strain. Growth at 25oC for 7 days achieved optimal mycelial growth of 61.9±2.10 mm, superior to growth of the parent strain at this temperature. The cap shape of Heunghwa 1ho was convex, cap diameter was 57.8±8.31 mm, and cap color was brown. Heunghwa 1ho showed similar genetic traits to those of the parental strain. However, dry weight (20.1 kg/m3) and cap diameter and color are superior to those of the parent strain. The 3 year fresh oak mushroom yield was 113.8 kg/m3, superior to the respective yields of the parent strains JMI 10047 and JMI 90021 (92.5 kg/m3 and 66.4 kg/m3).

To optimize initial cooling conditions, forced-air cooling was applied to freshly harvested oak mushrooms at 2 levels (0oC for 30 minutes, at 0oC for 1 hour) followed by room cooling at 3 levels (-3oC for 1 day, 0oC for 1 day, 3oC for 1 day). After initial cooling, the oak mushrooms were packaged with PVC film, then held in a storage room at 1oC for 6 weeks. Quality characteristics and percentage marketability were then investigated. As a control, Mushrooms were placed in storage with no initial cooling. The quality factors impacting marketability of fresh oak mushrooms were color change and appearance of decay. Off-odor did not occur or developed only slightly, so it did not affect oak mushroom quality within 6 weeks of low temperature storage. In all treatment groups, the shelf life in which 100% marketability was maintained was up to 3 weeks. At week 5, percent marketability of the 3 treatment groups 1 hour room cooling treatment at 0°C, 1 hour forced air cooling, and control was 100%. 80% In the group that underwent 30 min forced air cooling retained 80% marketability, and the group exposed to 1 day in room cooling at -3oC retained 86.7% marketability. At week 6 of 1oC storage, the marketability ratio was 80% in the 1 day room cooling at 0oC group, 66.7% in the 1 day room cooling at 3oC group, 46.7% in the 1 hour forced air cooling group, and 33% or less in all other treatment groups. Therefore, the most suitable initial cooling parameter to extend shelf-life of oak mushrooms is 1 day of in room cooling at 0oC immediately after harvest.

As the importance of public health increases with the spread of infectious diseases, functionality has become a factor affecting consumers’ purchase of mushrooms. Therefore, the bioactive components of button mushrooms (Agaricus bisporus), which are generally known to promote button mushroom consumption, were analyzed. White and brown button mushrooms were compared and white beech mushroom (Hypsizygus marmoreus) were used as a control. White button mushrooms had higher sugar and inorganic potassium concentrations than brown button mushrooms, whereas sodium, magnesium, and vitamin C concentrations were not significantly different between the different button mushrooms. Moreover, there was approximately twice as much ergosterol in white button mushrooms than brown button mushrooms. Brown button mushrooms had higher concentrations of β-glucan and oxalic acid than white button mushrooms, but there was no significant difference in total organic acid content between the two mushroom types. High concentrations of the essential amino acids, ergothioneine, isoleucine, and leucine and the non-essential amino acids, glycine and alanine, were observed. Concentrations of the vitamin B group and total polyphenols were also high.

This study was conducted to investigate the growth and antioxidant activity of Pleurotus ostreatus mycelia grown in medium supplemented with Aronia. The diameter and dry weight of the mycelia were increased in the medium supplemented with Aronia compared with the untreated medium. The total polyphenol content of mycelia grown in medium supplemented with Aronia and untreated medium was 6.54 mg GAE/g and 5.77 mg GAE/g, respectively. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of mycelia grown in medium supplemented with Aronia and untreated medium was 61.81% and 49.65%, respectively. Moreover, the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity of mycelia grown in medium supplemented with Aronia and untreated medium was 59.83% and 52.66%, respectively. These results confirmed that P. ostreatus mycelial growth and antioxidant activity were increased when Aronia was added to the culture medium.

While protecting its lives and property from natural disasters such as floods and droughts, North Korea needs to develop into an informationized industrial society by securing renewable energy power in the era of energy transition. In addition, existing research has considered that a policy of continuous and consistent expansion of renewable energy based on the safety of the lives of ordinary people could be the solution. South Korea needs to recognize that the supply of energy for a minimum of living is more important to the North Korean people than the economic benefits of securing North Korea's renewable energy market. Therefore, in this paper, from that point of view, we have calculated the amount of electricity that North Korea lacks necessary for the lives of its inhabitants that can be replaced by renewable energy, and considered ways to estimate the market value.