• Journal of Korea Water Resources Association
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• 제55권1호
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• pp.43-57
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• 2022

Advances in measurement techniques have reduced measurement costs and enhanced safety resulting in less uncertainty. For example, an acoustic doppler current profiler (ADCP) based suspended sediment concentration (SSC) measurement technique is being accepted as an alternative to the conventional data collection method. In Korean rivers, horizontal ADCPs (H-ADCPs) are mounted on the automatic discharge monitoring stations, where SSC can be measured using the backscatter of ADCPs. However, automatic discharge monitoring stations and sediment monitoring stations do not always coincide which hinders the application of the new techniques that are not feasible to some stations. This work presents and analyzes H-ADCP-SSC models for 9 discharge monitoring stations in Korean rivers. In application of the Gaussian mixture model (GMM) to sediment-related variables (catchment area, particle size distributions of suspended sediment and bed material, water discharge-sediment discharge curves) from 44 sediment monitoring stations, it is revealed that those characteristics can distinguish sediment monitoring stations regionally. Linking the two results, we propose a protocol determining the H-ADCP-SSC model where no H-ADCP-SSC model is available.

• The Journal of the Convergence on Culture Technology
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• 제8권2호
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• pp.281-289
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• 2022

Our society is rapidly changing with the core technology of the 4th industrial revolution, the emergence of a generation with new characteristics, and the untact era following the With Corona policy. Although the transition to untact is accelerating in the field of performing arts, in the case of opera, face-to-face performances are mainly conducted by experts and enthusiasts through on-site performances. Therefore, it is necessary to consider the uncertainty of creating opportunities through the influx of new customers such as the MZ generation and the departure of existing experts and enthusiasts. In this study, in order to examine these existing problems, we conducted literature review and case analysis, compared the opera face-to-face/non-face-to-face performance characteristics, derived an activation plan, and conducted expert interviews to secure the coherence and validity of the plan. In conclusion, we thought that it was difficult to improve the sound and sound quality, impairing the sense of presence and emotion due to many shortcomings when operating non-face-to-face as a music genre with the characteristics of opera. Therefore, we established the direction of activating the opera mainly face-to-face, but making good use of the advantages of non-face-to-face, which is not limited by region and time, and promoting the direction of activating face-to-face and non-face-to-face performances complementary to each other through the concept of cultural enjoyment.

• Journal of Korea Water Resources Association
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• 제55권3호
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• pp.245-255
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• 2022

Evaluating the qualitative the qualitative process of water resources by using various indicators, as one of the most prevalent methods for optimal managing of water bodies, is necessary for having one regular plan for protection of water quality. In this study, zoning maps were developed on a yearly basis by collecting and reviewing the process, validating, and performing statistical tests on qualitative parameters҆ data of the Iranian aquifers from 1995 to 2020 using Geographic Information System (GIS), and based on Inverse Distance Weighting (IDW), Radial Basic Function (RBF), and Global Polynomial Interpolation (GPI) methods and Kriging and Co-Kriging techniques in three types including simple, ordinary, and universal. Then, minimum uncertainty and zoning error in addition to proximity for ASE and RMSE amount, was selected as the optimum model. Afterwards, the selected model was zoned by using Scholar and Wilcox. General evaluation of groundwater situation of Iran, revealed that 59.70 and 39.86% of the resources are classified into the class of unsuitable for agricultural and drinking purposes, respectively indicating the crisis of groundwater quality in Iran. Finally, for validating the extracted results, spatial changes in water quality were evaluated using the Groundwater Quality Index (GWQI), indicating high sensitivity of aquifers to small quantitative changes in water level in addition to severe shortage of groundwater reserves in Iran.

• Journal of Food Hygiene and Safety
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• 제36권6호
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• pp.474-480
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• 2021

Sodium alginate is the sodium salt of alginic acid, commonly used as a food additive for stabilizing, thickening, and emulsifying properties. A relatively simple and universal analysis method is used to study sodium alginate due to the complex pretreatment process and extended analysis time required during the quantitative method. As for the equipment, HPLC-UVD and Unison US-Phenyl column were used for analysis. For the pretreatment condition, a shaking apparatus was used for extraction at 150 rpm for 180 minutes at room temperature. The calibration curve made from the standard sodium alginate solution in 5 concentration ranges showed that the linearity (R²) is 0.9999 on average. LOD and LOQ showed 3.96 mg/kg and 12.0 mg/kg, respectively. Furthermore, the average intraday and inter-day accuracy (%) and precision (RSD%) were 98.47-103.74% and 1.69-3.08% for seaweed jelly noodle samples and 99.95-105.76% and 0.59-3.63% for sherbet samples, respectively. The relative uncertainty value was appropriate for the CODEX standard with 1.5-7.9%. To evaluate the applicability of the method developed in this study, the sodium alginate concentrations of 103 products were quantified. The result showed that the detection rate is highest from starch vermicelli and instant fried noodles to sugar processed products.

• Journal of The Korean Association For Science Education
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• 제42권2호
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• pp.253-264
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• 2022

The purpose of this study is to examine the practice of scientists from the perspective of Ian Hacking's 'creation of phenomena'. Scientific phenomena, according to Hacking, are regular and do not exist in nature without the intervention of scientists or experimental tools. This study tries to derive scientific educational meaning by analyzing the thoughts and episodes of the 'Sontanda (inter-individual variability)' phenomenon experienced by four life scientists. The Sontanda phenomenon is a common term used by scientists to describe phenomena in which findings do not appear consistently even when studies are carried out using the same experimental procedure and materials. The following four educational implications were discovered as a result of the research. First, we confirmed the importance of embodied knowledge, or non-verbal knowledge, which solves issues by making appropriate judgments and reactions at all times, rather than simply becoming accustomed to the experimental method. This argues that propositional knowledge and non-verbal knowledge should be handled equally in order to provide students with a practical scientific inquiry. Second, we tried to reconsider the picture of the experiment. The phenomenon revealed in the interviews of scientists is rare, and it takes a long time to stabilize the phenomenon. On the other hand, the image of school experiments is always positive and consistent, necessitating a shift in perspective. Third, the precise meaning of scientific practice could be confirmed. This study confirms that scientists use their knowledge effectively in line with the circumstances, and we examined strategies to apply scientific practice to school instruction based on this. Finally, by provoking uncertainty, the Sontanda phenomena may give students with an opportunity to engage in meaningful scientific involvement. By breaking away from the cookbook experiment, this study expects school experimental education to help in efforts to experience scientific practice.

• Journal of Industrial Convergence
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• 제19권6호
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• pp.21-35
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• 2021

The purpose of this paper is to examine how demand for labor affects the job seeker's decision on the level of investment in education. In the current paradigm of economic growth in which innovations and technological developments generally weaken the strength demand for labor and increases the uncertainty related to employment, this paper provides a theoretical framework that can be used as a basic framework in understanding the decision of investment in education in varying conditions of demand for labor. The following are the findings of this paper. First, the level of investment in education can generally be regarded to be higher as the demand for labor exacerbates but for the job seekers with a certain characteristic. Second, the Arrow-Pratt absolute risk-aversion measure is the characteristic of the job seeker that determines in what direction the job seeker changes in the level of investment in education, For an arbitrary level of demand for labor there exists a certain threshold which determines the minimum degree of risk-aversion required for the job seeker's Arrow-Pratt should go over to increase the level of education as demand for labor weakens. Third, the job seekers lower the level of education even though the demand condition in labor markets weakens if the compensation function does not depend on the level of education. This is surprising because it turns out that one of the reasons why job seekers invest in education is that they want to be recognized in their compensation for their level of education even when more education still raises the probability of employment.

• Maritime Security
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• 제3권1호
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• pp.73-114
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• 2021

This study examines the distribution of power in Northeast Asia based on the balance of power theory, a representative theory of realism, assuming military capabilities as the core power of states. The results of previous studies on the balance of power and military forces are reviewed and used to analyze changes in the strength of the US, China, Russia, Japan, South Korea, and North Korea through 2020 to predict the security environment in 2030. In the balance of power theory, if the balance of power between a nation or a group of powers collapses, the possibility of war is high, and to survive in the international community with high uncertainty and distrust, the theory predicts that states must increase their powers in a self-help world and strengthen cooperation and alliance. Countries in Northeast Asia are also continuing to strengthen their military capabilities, and countries neighboring China are paying keen attention and remaining vigilant due to the rapid changes in the international security environment after the rapid rise of China. To mark the future 100th anniversary of the Chinese armed forces in the 2030s, China aims to realize 'defense and military modernization' and build a 'world-class military force' by the nation's 100th anniversary in the 2050s. The US is busy checking China's rise by strengthening international cooperation and alliances. The security environment and power dynamics in Northeast Asia are slowly changing as the US and China continue to compete for global hegemony. The changes and implications of the distribution of power in Northeast Asia after 2030 are examined based on the balance of power theory.

• Korean Journal of Agricultural and Forest Meteorology
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• 제24권1호
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• pp.35-47
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• 2022

Expansion of potato production areas can improve the food security in North Korea because the given crop has less requirements for agricultural materials and facilities. The Global Agro-Ecological Zones (GAEZ) model, which was developed to evaluate climate suitability under different cultivation conditions, was used to identify potential areas for the potato production. The spatial estimates of crop suitability under low and high input management conditions were downloaded from the GAEZ data portal. The values of suitability were obtained at the potato occurrence sites retrieved from the Global Biodiversity Information Facility (GBIF) database. The suitable areas for the potato production were identified using a threshold value derived from the suitability estimates at the occurrence sites. It was found that 90% of the occurrence sites had the suitability index value >3,333, which was set to be the threshold value. The suitable areas in North Korea were summarized by province and county. Rice cultivation areas were excluded from the analysis. The reported relative acreage of potato production was better represented by the suitable areas under the low input management options than the high input conditions. The suitable areas also had a similar distribution to the reported acreage of potato production by county. These results indicated that the GAEZ model would be useful to identify the candidate production areas, which would facilitate the increases in potato production especially under future climate conditions. Furthermore, monthly maps of crop suitability can be used to design cropping systems that would improve crop production under the limited use of agricultural materials and facilities.

• Journal of Korea Water Resources Association
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• 제55권7호
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• pp.505-513
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• 2022

Recently, uncertainty in predicting available water resources is gradually increasing due to climate change and extreme weather conditions. Social interest in water management such as flood and drought prevention is also increasing, and after the unification of water management implemented in 2018, domestic water management is facing a major turning point. As part of such strengthening of water management capabilities, various studies are being conducted to utilize a hydropower dam for flood control and water supply purposes, which was mainly operated for hydroelectric power generation. However, since the dam evaluation methods developed based on a multi-purpose dam are being applied to hydropower dams, an additional evaluation approach that can consider the characteristics of hydropower dams is required. In this study, a new water supply capacity evaluation method is presented in consideration of the operational characteristics of hydropower dams in terms of water supply, and a connected reservoir simulation method is proposed to evaluate the comprehensive water supply capacity of a dam group operating in a river basin. The presented method was applied to the hydropower dams located in the Bukhan River basin, and the results of the water supply yield of individual dams and multi-reservoir systems were compared and analyzed. In the future, the role of hydropower dams for water supply during drought is expected to become more important, and this study can be used for sustainable domestic water management research using hydropower dams.

• Journal of Korea Water Resources Association
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• 제55권7호
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• pp.545-556
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• 2022

It is recommended to use long-term hydrometeorological data for more than the service life of the hydraulic structures and water resource planning. For the purpose of expanding rainfall data, stochastic simulation models, such as Modified Bartlett-Lewis Rectangular Pulse (BLRP) and Neyman-Scott Rectangular Pulse (NSRP) models, have been widely used. The optimal parameters of the model can be estimated by repeatedly comparing the statistical moments defined through a combination of parameters of the probability distribution in the optimization context. However, parameter estimation using relatively small observed rainfall statistics corresponds to an ill-posed problem, leading to an increase in uncertainty in the parameter estimation process. In addition, as shown in previous studies, extreme values are underestimated because objective functions are typically defined by the first and second statistical moments (i.e., mean and variance). In this regard, this study estimated the parameters of the NSRP model using the objective function with the third moment and compared it with the existing approach based on the first and second moments in terms of estimation of extreme rainfall. It was found that the first and second moments did not show a significant difference depending on whether or not the skewness was considered in the objective function. However, the proposed model showed significantly improved performance in terms of estimation of design rainfalls.