• Journal of Korean Society of Disaster and Security
• /
• v.11 no.2
• /
• pp.29-35
• /
• 2018

This study is an experimental comparison on the fact that the sinusoidal load, which has been used so far in the laboratory cyclic test, which is an important part of the liquefaction triggering study, is somewhat different from the phenomenon that causes the soil liquefaction during the earthquake loading. To this end, this study proposes a new type of combined sinusoidal load and compares it with experimental results to load the conventional sine wave. In the comparison, the shaking table tests were carried out and the sample in the tests was remolded with the relative density of 40%, which is a condition where liquefaction is easy to occur. Firstly, the conventional cyclic test was carried out under the condition that with the amplitude of sine wave was 0.3 g. Additionally, 3 types of tests were performed using the combination loads made up with 0.03 g sinusoidal load and 0.3g sinusoidal load. At that time, the loading time for the first sinusoidal load were changed with 5 seconds, 10 seconds, and 15 seconds. As a result, the test with the conventional sine wave and the test with the first sinusoidal loading for 5 seconds showed that the change of the pore water pressure gradually increased. But in the tests with the combined sinusoidal load which changed the first sinusoidal loading time with 10 and 15 seconds, it was found that the pore water pressure suddenly rose at a certain instant and liquefaction occurs. From the experimental comparison, it is judged that it is appropriate that the time of the first sine wave is over 10 seconds at the proposed combined load for the soil condition with relative density 40%.

• Journal of Nutrition and Health
• /
• v.56 no.1
• /
• pp.35-53
• /
• 2023

Purpose: The purpose of the first part of this study was to evaluate the validity of the physical activity classification table for youth (Youth-PACT). The second part of this study was aimed at comparing the estimated energy requirement (EER) with the total energy expenditure (TEE) and evaluating the physical activity patterns of Korean children and adolescents. Methods: The subjects of the first part of the study were 17 children aged 10 to 12 years, and their total energy expenditure (TEE_DLW) was measured using the double labeled water (DLW) method. A total of 166 children and adolescents aged 6-18 years participated in the second part of this study. Their resting energy expenditure (REE) was measured using indirect calorimetry and the TEE_Youth-PACT and physical activity level were calculated by applying the Youth-PACT to the physical activity diary prepared by the subjects. Results: In the first part of this study, there were no significant differences between the TEE_DLW and the TEE_Youth-PACT. The TEE_Youth-PACT accurately predicted TEE_DLW in 37.5% of the subjects. In the second part of the study, the rates at which EER accurately predicted TEE _YouthPACT and overestimated TEE _Youth-PACT were 29.6% and 47.3%, respectively. The time spent based on intensity of physical activity and the physical activity categories which were obtained using Youth-PACT showed different patterns according to sex and age group. Age showed significant positive correlations with REE, TEE, and the time spent in sedentary behavior, but age was significantly negatively correlated with REE/body weight, TEE/body weight, and the time spent in low-intensity and high-intensity activities. Conclusion: The results of this study showed that the Youth-PACT can be used to evaluate the TEE and PAL of children and adolescents. However, further studies are needed to validate the TEE_Youth-PACT and to set the EER for children and adolescents.

• The Journal of Korean Academy of Sensory Integration
• /
• v.21 no.1
• /
• pp.59-73
• /
• 2023

Objective : To examine changes in participation patterns of children with Autism Spectrum Disorder (ASD) in play activities during COVID-19 by reviewing relevant literature. Methods : This scoping review was conducted via five steps. we created a research question and searched for relevant literature published in English through CINAHL, PubMed, ERIC, MEDLINE, Google Scholar and Google search engine. After selecting the literature based on inclusion criteria, data were charted based on 10 items (i.e., author name, journal name, publication year, nation, authors' majors, research method, participant' age and gender as well as quantitative and qualitative results of study). The results were analyzed using descriptive numerical and thematic analyses. Results : After reviewing 437 articles and 152 websites, six articles were included. Theses articles were conducted by experts from various fields and countries. Five themes were highlighted in selected articles: COVID-19 resulted in (1) decreased time of outdoor play, (2) increased play time on screen, (3) increased time spent with family, (4) increased sensory difficulties, and (5) recommendations for services for children with disabilities and during COVID-19. Conclusion : This study suggests telerehabilitation programs about parental behavior strategies in order to solve difficulties in which children with ASD may experience when participating in play activities during disasters. Study results can be used as fundamental evidence to emphasize importance of play activities and to systematize role of occupational therapists and service guidelines for supporting play activities of children with disabilities in disasters.

• Journal of Food Hygiene and Safety
• /
• v.38 no.6
• /
• pp.528-536
• /
• 2023

In Korea, from January 2023, the Act on Labeling and Advertising of Food was revised to reflect the use-by-date rather than the sell-by-date. Hence, the purpose of this study was to establish a system for calculating the safety factor and determining the recommended use-by-date for each food type, thereby providing a scientific basis for the recommended use-by-date labels. A safety factor calculation technique based on scientific principles was designed through literature review and simulation, and opinions were collected by conducting surveys and discussions including industry and academia, among others. The main considerations in this study were pH, Aw, sterilization, preservatives, packaging for storage improvement, storage temperature, and other external factors. A safety factor of 0.97 was exceptionally applied for frozen products and 1.0 for sterilized products. In addition, a between-sample error value of 0.08 was applied to factors related to product and experimental design. This study suggests that clearly providing a safe use-by-date will help reduce food waste and contribute to carbon neutrality.

• Journal of Wetlands Research
• /
• v.17 no.1
• /
• pp.1-10
• /
• 2015

The bleaching phenomenon of otter spraints is indicates that the age of spraints (fresh or old spraints). As previous studies on the old otter faeces (spraint) have focused only on the external changes of spraints, it has been difficult to explain the difference of the decomposition rates among old spraints. We hypothesized that the micrometeorology difference caused by various characteristics of sprainting sites such as porosity and consistency of soil could affect the extent of the decomposition rate, the solar bleaching phenomenon of spraints used as a measure of the patterns of old spraints. Sprainting sites were classified into four types (Clay, Sand, Rock and Concrete spot) and each type was divided into two groups according to the sunlight condition (Sunny site and Shady site) to measure the effect of solar radiation. Micrometeorology of the sites were evaluated by measuring temperatures and humidities of the sites during the whole season. The variations in micrometeorology of the sunny sites according to the sprainting site types were examined with correlation analyses between the factors of micrometeorology. The analyses on the bleaching phenomenon of the spraints by micrometeorology showed that the highest rate of bleaching was found at the 'Rock spot' and 'Concrete spot' of the sunny site and especially in summer, the highest rate of bleaching ($63.4{\pm}7.6%$) was found at the 'Clay spot' of the sunny sites. The lowest rate of bleaching was found at the 'Sand spot' of the sunny sites. The above findings show that the difference in bleaching rates among sprainting sites was due to the seasonal or sunny condition. In addition, we found that the differences in thermal conductivity among sprainting site characteristics have resulted in different sprainting site temperature which have affected the rate of bleaching of spraints. In conclusion, this study suggests that studies of otters on their population size and home ranges using spraints as an indirect sign, should consider the effects of sprainting site characteristics and weather conditions.

• Korean Journal of Environmental Biology
• /
• v.37 no.4
• /
• pp.625-639
• /
• 2019

Microplastics are one of the substances threatening the marine ecosystem. Here, we summarize the status of research on the effect of microplastics on marine life and suggest future research directions. Microplastics are synthetic polymeric compounds smaller than 5 mm and these materials released into the environment are not only physically small but do not decompose over time. Thus, they accumulate extensively on land, from the coast to the sea, and from the surface to the deep sea. Microplastic can be ingested and accumulated in marine life. Furthermore, the elution of chemicals added to plastic represents another risk. Microplastics accumulated in the ocean affect the growth, development, behavior, reproduction, and death of marine life. However, the properties of microplastics vary widely in size, material, shape, and other aspects and toxicity tests conducted on several properties of microplastics cannot represent the hazards of all other microplastics. It is necessary to evaluate the risks according to the types of microplastic, but due to their variety and the lack of uniformity in research results, it is difficult to compare and analyze the results of previous studies. Therefore, it is necessary to derive a standard test method to estimate the biological risk from different types of microplastics. In addition, while most of the previous studies were conducted mostly on spheres for the convenience of the experiments, they do not properly reflect the reality that fibers and fragments are the main forms of microplastics in the marine environment and in fish and shellfish. Furthermore, studies have been conducted on additives and POPs (persistent organic pollutants) in plastics, but little is known about their toxic effects on the body. The effects of microplastics on the marine ecosystems and humans could be identified in more detail if standard testing methods are developed, microplastics in the form of fibers and fragments rather than spheres are tested, and additives and POPs are analyzed. These investigations will allow us to identify the impact of microplastics on marine ecosystems and humans in more detail.

• Journal of Environmental Policy
• /
• v.6 no.1
• /
• pp.1-40
• /
• 2007

The research in this paper, for the effective implementation of CBD PoW PA(Program of Work on Protected Areas of Convention on Biological Diversity) that was adopted by CBD COP7(Conference of the Parties) in 2004, shows the objectives and activities of 9 each subject in PoW PA regarding domestic status and cases of national park management. Before anything else, according to the result of the review on the status of protected areas in Korea, there are 1,119 protected areas which are classified into 14 types and the total area is about $15,621km^2$. After a thorough review on 9 each subject about the implementation of CBD PoW PA, we found out that some parts such as management planning, prevention and alleviation of threats, and establishment of PAs system, are improved while financial support, improved social benefit, and MEE(Management Effectiveness Evaluation} fields are need to be improved. Especially regarding time-bound, ecological gap analysis on national level and MEE are need to be improved immediately. This paper could help us to understand the current status of PAs management system in Korea and to prepare national reports of CBD and implementation report of PoW PA. Based on research and results of this paper, we need to find the fields that have gaps in order to meet the requirements of the CBD PoW PA and the implementation tools that are suitable for managing Korea's protected areas. To effectively implement the various activities which require a systematic approach on the national level, the establishment of the networks among relevant organizations for protected areas are vital. To effectively reach the ultimate goal of CBD PoW PA, reducing the rate of biodiversity loss, it is essential that lots of plans established by authorities must be carried out in a constant manner to achieve goals of CBD PoW PA.

• 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.

• Korean Journal of Environment and Ecology
• /
• v.23 no.1
• /
• pp.90-98
• /
• 2009

Every spring, Korea is always plagued by sandy dust from the western region of China and Mongolia. Yellow sand is causing an environmental problem to Japan and far into the American continent, let alone Korea. At present, the western region of China is going under desertification at a great speed due to climatic change and humans' damaging activities. To cope with this, each country including China is considering ecological restoration of deserts through planting. Accordingly, this research conducted a vegetation survey on Baicheng district which is a representative dry land of western China to obtain a basic data for ecological restoration of a desert. The survey revealed that Setaria viridis which invaded an arid land made a succession into Setaria viridis-Cannabis sativa var. fruderalis community together with Artemisia mongolica-Setaria viridis community due to the increase in salt concentration and alkalization subsequent to dryness. It was also found out that there finally formed Artemisia mongolica community on a flat intense in harsh wind and dryness with the continuous worsening of environmental conditions. There appeared a different type of vegetation on hilly districts where sporadic shade could come into being because the air humidity could be available relatively there. Frequently, typically appearing at the whole survey area, the Tributlus terrestris community was found to make succession into Tribulus terrestris-Cleisrogenes squarrosa community due to the aggravation of soil environment. In addition, with the worsening of the environment at hilly districts, there formed Clesirogenes squarrosa community resistant to dryness, salinity in soil and strong alkalinity. Further, there appeared higher plant life totalling to 62 taxa comprising 58 species and 4 varieties with 27 families and 49 genuses at the whole survey area. Among these, Compositae plants excellent in resistance to environment was surveyed the most, accounting for 27%.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.28 no.4
• /
• pp.36-48
• /
• 2010

The objectives of this study are to research and analyze the positioning of Mt. Back Hwa(白華山) and the characteristics of its neighboring cultural scenery based on the Two Seated Buddah Temple, a small Buddhist temple of Taeul in Taean and to view both landscape geographic codes and religious attractions over Mt. Back Hwa by discussing its expression and meaning for the scenery scattered or nested over this districts. The panoramic view of west shows the character of Mt. Back Hwa as a magnanimity of Buddhist Goddess of Mercy which is viewed as a view point field no less than its location as a landscape target and its singularity as a rocky mountain. The ancient castle, signal beacon post and the small Buddhist temple of Taeul to be read importantly in the old map and SinjeungDongkukyeojiseungram(新增東國輿地勝覽) form the core of place identity, and a number of carve(engrave) letters such as Eopungdae(御風臺), Youngsadae(永思臺), etc. show the prospect of this mountain and monumentality derived from place characteristics. In addition removing of Taeiljeon, a portrait scroll of Dangun, national ancestor makes possible to guess the national status hold by Mt. Back Hwa in advance and to know that it has symbiotic relationship with indigenous religion and shares with the universal locality which have been continued for a long time through a portrait scroll of Dangun enshrined in Samsunggak. More than anything else, however the Rock-carved Buddha Triad in Taean, Giant Buddha of Baekjae era enshrined in the small Buddhist temple of Taeul is not only why Mt. Back Hwa, magnanimity of Buddhist Goddess of Mercy exists but also a signifier. In spite of such a placity, the union ideas of confucianism, buddhism and doctrinism of buddhism prevailed in the Late Joseon Dynasty allows the cultural phenomenon of taoism to be read in the same weight through Ilsogae(一笑溪) and Gammodae(感慕臺) which are mountain stream and pond area respectively centered in the carve letter, 'Taeeuldongcheon(太乙洞天)' constructed in front of the small Buddhist temple of Taeul, the Baduk board type of rock carvings engraved over them and a number of traces of carve letters made by confucian scholars since the Middle of Joseon Dynasty. The reason such various cultural sceneries are mixed in Mt. Back Hwa is in the results of inheritance of religious places and fusion of sprit of the times, and the various type of cultural scenery elements scattered in Mt. Back Hwa are deemed as unique geographic code to understand the multi-layered placity and the characteristics of scenery of Mt. Back Hwa in Taean.