• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.42 no.3
• /
• pp.379-389
• /
• 2022

The number of public transportation users has dropped drastically due to COVID-19. In this work, my survey was conducted to uncover the factors that influence citizens' travel patterns. Data were collected and logistic regression analysis on the shifts in transportation was undertaken. Additionally, an importance-performance analysis was carried out to investigate how to effectively operate public transportation systems and improve facilities. The main research findings were as follows: First, the more individuals were concerned about COVID-19 (+) and being infected when using public transportation (+), the greater the tendency to switch to private transportation modes. Secondly, when it came to personal traits, respondents who could drive a car (+) or owned a car (+)or did more online shopping (+) or used public transportation for trips (+) tended to switch over, compared with respondents who could not drive or did not own a caror used public transportation to commute. In addition, respondents who were vaccinated (-) or had more household members tended not to switch transportation modes, compared with those who were not vaccinated or had fewer household members. Third, it is important to continue the following efforts to safeguardhygiene linked to public transportation: wearing masks, disinfecting hands, controlling diseases, and general cleaning. The conclusion was that it is important to put traffic congestion and ventilation issues first, especially in regards public transportation, which was not rated as satisfactory enough compared to its importance. The research findings can provide useful basic data when establishing countermeasures to the current COVID-19 circumstances in the areas of public transportation operation and management and in the event of an infectious disease outbreak in the future.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.18 no.1
• /
• pp.63-70
• /
• 2016

This study was conducted to investigate the effect of atmosphere-leaf vapor pressure deficit (VPD) in Heracleum moellendorffii and Aruncus dioicus var. kamtschaticus. The VPD was rapidly increased with increasing temperature and decreasing relative humidity. Taken as a whole, the stomatal transpiration reaction was slightly late with increasing of VPD. Maximum photosynthetic rate at high-VPD condition was 6.49 µmol CO₂·m^-2·s^-1 in Heracleum moellendorffii Hance, which was a little lower than 5.57 µmol CO₂·m^-2·s^-1 in Aruncus dioicus var. kamtschaticus, respectively. After 2 p.m, stomatal transpiration of Heracleum moellendorffii at the high VPD condition was rapidly decreased. The results indicated that physiological activities in Heracleum moellendorffii are more limited from high VPD conditions.

• The Korean Journal of Archival Studies
• /
• no.23
• /
• pp.141-178
• /
• 2010

The Administration of Labor was responsible for the technical and practical functions like policy-making of labor matters and implementing the relevant laws. However, there has been a few record transferred to the National Archives to help find out the labor policy-making process. This is one of the typical examples that shows the discontinuity and unbalance, and disorderly filing of the administrative records in Korea. Naturally it is almost impossible to retrieve the appropriate content through the records file-name. Users should be at the trouble to compare the record items and their content one by one. For the re-organization of the Administration of Labor' records, this research suggests the four-level analysis of functions of the Administration. The Administration of Labor' survived records could be linked to each level function. And the publication of the 'Records Abstract Catalog' providing users with more information about the records would pave the way for easier access to the records. In addition, it also suggests the logical re-filing of the survived records of which we cannot find the order or sequence. This re-organization of the survived records would help to establish the acquisition and appraisal policy of the labor records as well as the new way of description and finding tool hereafter. Drawing up labor history map is a starting point for the acquisition strategy of the labor records, which could allow users to gain systematic access on the survived records. Of course, extensive investigation and research on the survived records is a prerequisite for the map. It would be required to research on the survived records of the other government agencies, including economic-social area ministries and investigation agencies and the National Assembly as well. It is also needed to arrange and typify the significant incidents and activities on thematic and periodic frames in the labor history. If possible to understand or connect the survived records and these accomplishments comprehensively, it would be of great help for the acquisition of the labor records and the related oral records projects.

• Journal of Nutrition and Health
• /
• v.56 no.5
• /
• pp.510-522
• /
• 2023

Purpose: In this study, data from the 7th Korea National Health and Nutrition Examination Survey (2016-2018) were used to examine the relationship between the prevalence of anemia and dietary intake among adults according to household types. Methods: Using data from a total of 10,646 subjects (4,428 men and 6,218 women), the general information, body measurements, results of biochemical examination, food and nutrient intake, and meal quality evaluation were analyzed according to the type of household. Results: The prevalence of anemia was higher in men belonging to single-person households (SPH) than in those from multi-person households (MPH), while anemia prevalence was higher among the women in the MPH than in the SPH. The men in SPH had a lower total food intake of nuts, vegetables, fruits, fish, and seaweed than the men in MPH, and consumed higher quantities of milk, oil, and processed foods. The women from SPH had a lower intake of seaweed and a higher intake of milk than those belonging to the MPH. In addition, the men in SPH had a lower iron intake and iron intake per 1,000kcal than the men in MPH, lower iron intake through plant-based foods, and a lower iron intake ratio compared to the reference nutrient intake. The total Korean Healthy Eating Index (KHEI) score was lower in both men and women in SPH than in those from the MPH. When analyzing the relationship between household type and anemia risk after correcting for the confusion variable, the risk of anemia in men in SPH increased compared to those belonging to the MPH. However, women showed no such significant correlation. There was no relationship between the total KHEI score and the risk of anemia by gender and household type. Conclusion: In conclusion, since anemia in men belonging to SPH is a matter of concern, it is essential to develop guidelines for anemia-related nutrition education for men living alone.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.7 no.2
• /
• pp.51-59
• /
• 2002

The seasonal variation in species composition and abundance distribution of zooplankton was studied in the Seomjin river estuary along the salinity gradients. In this estuary, marine taxa predominated in all seasons and very limited number of freshwater species appeared. The total abundances showed a seasonal fluctuation. The highest total abundance appeared in spring with over 3,000 individuals/m$^3$. In summer, the high abundance was sustained although it decreased a little. The abundance was minimal in fall with about 500 individuals/m$^3$. When the study area was divided into three salinity regimes, oligohaline (salinity less than 5 psu), mesohaline (5${\sim}$18 psu), and polyhaline zone (over 18 psu), the zone of high abundance as well as the composition of zooplankton community in each salinity regime changed seasonally. In fall, marine copepods predominated in oligohaline zone while marine species other than crustaceans dominated in polyhaline zone. However, in winter copepods predominated in all area. In spring and summer, holozoic dinoflagellate Noctiluca scintillans dominated in higher salinity regimes. We listed major copepod species of each salinity regime for each season with the ranges of water temperatures (T) and salinities (S) of their occurrence. T, S's of maximum abundances of those major copepod species were also reported. The observed very wide tolerance ranges of major copepod species for salinity suggested that the concept of 'indicator species' should be used in quantitative context rather than qualitative.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.6
• /
• pp.1731-1741
• /
• 2014

Recently, many overpasses, highway, and advanced transit systems have been constructed to distribute the traffic congestion, thus small size of curved bridges with small curvature such as ramp structures have been increasing. Many of early curved bridges had been constructed by using straight beams with curved slabs, but curved steel beams have replaced them due to the cost, aesthetic and the advantage in building the section form and manipulating the curvature of beams, thereby large portion of curved bridges were applied with steel box girders. However, steel box girder bridges needs comparatively high initial costs and continuous maintenance such as repainting, which is the one of the reason for increasing the cost. Moreover, I-type steel plate girder which is being studied by many researchers recently, seem to have problems in stability due to the low torsional stiffness, resulting from the section characteristics with thin plate used for web and open section forms. Therefore, in recent studies, researchers have proposed curved precast PSC girders with low cost and could secured safety which could replace the curved steel girder type bridges. Hence, this study developed a Smart Mold system to manufacture efficient curved precast PSC girders. And by using this mold system a 40 m 2-girder bridge was constructed for a static flexural test, to evaluate the safety and performance under ultimate load. At the manufacturing stage, each single girder showed problems in the stability due to the torsional moment, but after the girders were connected by cross beams and decks, the bridge successfully distributed the stress, thereby the stability was confirmed. The static loading test results show that the initial crack was observed at 1,400 kN when the design load was 450 kN, and the load at the allowable deflection by code was 1,800 kN, which shows that the safety and usability of the curved precast PSC bridge manufactured by Smart Mold system is secured.

• Journal of the East Asian Society of Dietary Life
• /
• v.18 no.5
• /
• pp.732-738
• /
• 2008

This study was carried out to examine information regarding nutritional intake according to intake of health improving agents. For this study, 593 adults were interviewed face-to-face. The average ages of the participants were 58.8 years old in males and 56.1 years old in females. The percentage of individuals taking agents was significantly higher (p<0.05) among the females (22.1%) than the males (14.1%). Men showed a preference for taking animal protein bases restorative food and health supplements, while women preferred health supplements and nutritional supplements as improving agents. However, there were no significant differences between the two groups. The total daily food intake was also not significantly different according to intake of improving agents in the male and female groups. The male subjects who took improving agents showed significantly lower intake of potato and starches, pulses, fungi and mushrooms, seaweeds, oils and fat, as well as seasoning than those of non-users. Female subjects who took these agents also had a significantly lower intake of pulses, nuts and seeds than nonusers. No difference in the daily energy intake was reported in male and female groups whether the individuals were taking improving agents in male and female groups or not. However, in male subjects who took improving agents, there was a significantly lower intake of protein, dietary fiber, carotene, vitamin $B_1$, folate, vitamin C, vitamin E, plant calcium, potassium and plant iron than the male non-users. This study suggests that practical education be emphasized for proper nutrition intake thorough nutritional management according to improving agents.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.4 no.4
• /
• pp.113-125
• /
• 1984

Water supply has been mainly dependent on the construction of the dams in Korea. It is difficult, however, to continue to construct dams for many reasons, such as the decrease of construction sites, the increase of construction costs, the compensation of residents in flooded areas, and the environmental effects. Water demands have increased and are expected to continue increasing due to the concentration of people in the cities, the rise of the living standard, and rapid industrial growth. It is acutely important to find countermeasures such as development of ground water, desalination, and recycling of waste water to cope with increasing water demands. Recycling waste water includes all means of supplying non-potable water for their respective usages with proper water quality which is not the same quality as potable water. The usages of the recycled water include toilet flushing, air conditioning, car washing, yard watering, road cleaning, park sprinkling, and fire fighting, etc. Raw water for recycling is obtained from drainage water from buildings, toilets, and cooling towers, treated waste water, polluted rivers, ground water, reinfall, etc. The water quantity must be considered as well as its quality in selecting raw water for the recycling. The types of recycling may be classified roughly into closed recycle systems and open recycle systems, which can be further subdivided into individual recycle systems, regional recycle systems and large scale recycle system. The treatment methods of wastewater combine biochemical and physiochemical methods. The former includes activated sludge treatment, bio-disc treatment, and contact aeration treatment, and the latter contains sedimentation, sand filtration, activated carbon adsorption, ozone treatment, chlorination, and membrane filter. The recycling patterns in other countries were investigated and the effects of the recycling were divided into direct and indirect effects. The problems of water reuse in recycle patterns were also studied. The problems include technological, sanitary, and operational problems as well as cost and legislative ones. The duties of installation and administrative organization, structural standards for reuse of water, maintenance and financial disposal were also studied.

• Journal of the Korea Concrete Institute
• /
• v.25 no.3
• /
• pp.321-329
• /
• 2013

Recently, the medium-low level radioactive waste from nuclear power plant must be transported from temporary storage to the final repository. Medium-low level radioactive waste, which is composed mainly of the liquid ion exchange resin, has been consolidated with cementitious material in the plastic or iron container. Since cementitious material is brittle, it would generate cracks by impact load during transportation, signifying leakage of radioactive ray. In order to design the safety transporting equipment, there is a need to check the compressive strength of the current waste. However, because it is impossible to measure strength by direct method due to leakage of radioactive ray, we will estimate the strength indirectly by the dynamic modulus of elasticity. Therefore, it must be identified the relationship between of strength and dynamic modulus of elasticity. According to the waste acceptance criteria, the compressive strength of cement based solid is defined as more than 3.44 MPa (500 psi). Compressive strength of the present solid is likely to be significantly higher than this baseline because of continuous hydration of cement during long period. On this background, we have tried to produce the specimens of the 28 day's compressive strength of 3 to 30 MPa having the same material composition as the solid product for the medium-low level radioactive waste, and analyze the relationship between the strength and the dynamic modulus of elasticity. By controling the addition rates of AE agent, we made the mixture containing the ion exchange resin and showing the target compressive strength (3~30 MPa). The dynamic modulus of elasticity of this mixtures is 4.1~10.2 GPa, about 20 GPa lower in the equivalent compressive strength level than that of ordinary concrete, and increasing the discrepancy according to increase strength. The compressive strength and the dynamic modulus of elasticity show the liner relationship.

• Economic and Environmental Geology
• /
• v.35 no.5
• /
• pp.395-406
• /
• 2002

The sixty natural springs and community wells used as a drinking water in the Daejeon area are mainly located at the parks and the natural green districts. The purpose of this study is to investigate the characteristics of water quality and the contamination of the springs and the wells, and to suggest the management strategy for the springs and wells. For this study, we undertook water quality data from Daejeon City. According to the statistic analysis of water quality data, unacceptable rate as a drinking water was about 28 percent in 1999 and 24.5 percent in 2000, respectively. Major unacceptable factor is coliform, and others are bacteria, yersinia, color, turbidity, Fe and F. The unacceptable rate shows a roughly positive relationship with precipitation, that is, it shows highest rate during a rainy season between June and September. The major contamination source is likely to be the excrement of wild animals around natural springs and wells. Most of springs are vulnerable to the contamination of coliform and bacteria because of short residence time and shallow circulation in subsurface environment. The water samples collected from 31 springs or wells show weak acidic pHs, the electrical conductivity ranging from 63 to 357 $\mu\textrm{S}$/cm, and the hydrochemical types of Na(Ca)-HC0$_3$ and Ca-HC0$_3$. The groundwater samples of low total dissolved solid(TDS) belong to Na(Ca)-HC0$_3$. type, and the groundwater of high total dissolved solid is shifted towards Ca-HC0$_3$ type in the chemical composition. These hydrochemical characteristics indicate that most natural springs is in the early stage of geochemical evolution. The natural springs should be closed during a rainy season, which shows a high contamination rate. We suggest that a protection barrier around the springs should be built to keep wild animals away from the springs.