• Horticultural Science & Technology
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• v.34 no.1
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• pp.77-83
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• 2016

The measurement of total fresh weight of plants provides an essential indicator of crop growth for monitoring production. To measure fresh weight without damaging the vegetation, image-based methods have been developed, but they have limitations. In addition, the total plant fresh weight is difficult to measure directly in hydroponic cultivation systems because of the amount of nutrient solution. This study aimed to develop a real-time, precise method to measure the total fresh weight of Romaine lettuce (Lactuca sativa L. cv. Asia Heuk Romaine) with growth stage in a plant factory using a nutrient film technique. The total weight of the channel, amount of residual nutrient solution in the channel, and fresh shoot and root weights of the plants were measured every 7 days after transplanting. The initial weight of the channel during nutrient solution supply (Wi) and its weight change per second just after the nutrient solution supply stopped were also measured. When no more draining occurred, the final weight of the channel (Ws) and the amount of residual nutrient solution in the channel were measured. The time constant (${\tau}$) was calculated by considering the transient values of Wi and Ws. The relationship of Wi, Ws, ${\tau}$, and fresh weight was quantitatively analyzed. After the nutrient solution supply stopped, the change in the channel weight exponentially decreased. The nutrient solution in the channel slowly drained as the root weight in the channel increased. Large differences were observed between the actual fresh weight of the plant and the predicted value because the channel included residual nutrient solution. These differences were difficult to predict with growth stage but a model with the time constant showed the highest accuracy. The real-time fresh weight could be calculated from Wi, Ws, and ${\tau}$ with growth stage.

• Journal of Korea Water Resources Association
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• v.54 no.12
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• pp.1243-1254
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• 2021

For water resources operation or agricultural water management, it is important to accurately predict evapotranspiration for a long-term future over a seasonal or monthly basis. In this study, reference evapotranspiration forecast (up to 12 months in advance) was performed using statistically predicted monthly temperatures and temperature-based Hamon method for the Han River basin. First, the daily maximum and minimum temperature data for 15 meterological stations in the basin were derived by spatial-temporal downscaling the monthly temperature forecasts. The results of goodness-of-fit test for the downscaled temperature data at each site showed that the percent bias (PBIAS) ranged from 1.3 to 6.9%, the ratio of the root mean square error to the standard deviation of the observations (RSR) ranged from 0.22 to 0.27, the Nash-Sutcliffe efficiency (NSE) ranged from 0.93 to 0.95, and the Pearson correlation coefficient (r) ranged from 0.97 to 0.98 for the monthly average daily maximum temperature. And for the monthly average daily minimum temperature, PBIAS was 7.8 to 44.7%, RSR was 0.21 to 0.25, NSE was 0.94 to 0.96, and r was 0.98 to 0.99. The difference by site was not large, and the downscaled results were similar to the observations. In the results of comparing the forecasted reference evapotranspiration calculated using the downscaled data with the observed values for the entire region, PBIAS was 2.2 to 5.4%, RSR was 0.21 to 0.28, NSE was 0.92 to 0.96, and r was 0.96 to 0.98, indicating a very high fit. Due to the characteristics of the statistical models and uncertainty in the downscaling process, the predicted reference evapotranspiration may slightly deviate from the observed value in some periods when temperatures completely different from the past are observed. However, considering that it is a forecast result for the future period, it will be sufficiently useful as information for the evaluation or operation of water resources in the future.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.287-294
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• 2021

In order to expand facility agriculture and reduce greenhouse construction costs in reclaimed land, a greenhouse foundation method that satisfies economic feasibility and structural safety at the same time is required. As an alternative, the allowable bearing capacity and settlement were reviewed when the DCM(Deep cement mixing) method was applied among the soft ground reinforcement methods. To examine the applicability of the greenhouse foundation, the allowable bearing capacity and settlement were calculated by applying the theory of Terzaghi, Meyerhof, Hansen, and Schmertmann. In case of the diameter of 800mm and the width and length of the foundation of 4m, the allowable bearing capacity was 179kN/m² and the settlement was 7.25mm, which satisfies the required bearing capacity and settlement standards. The calculation results were verified through FEM(Finite element method) analysis using the Mohr-Coulomb material model. The allowable bearing capacity was 169kN/m² and the settlement was 2.52mm. The bearing capacity showed an error of 5.6% compared to calculated value, and the settlement showed and error of 65.4%. Through theoretical calculations and FEM analysis, it was confirmed that the allowable bearing capacity and settlement satisfies the design criteria as a greenhouse foundation when the width and length of the foundation were 4m. Based on the verified design values, it is expected to be able to present the foundation design criteria for greenhouses through empirical tests such as bearing capacity tests and long-term settlement monitoring.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.903-916
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• 2021

An area's topography refers to the shape of the earth's surface, described by its elevation, slope, and aspect, among other features. The topographical conditions determine energy flowsthat move water and energy from higher to lower elevations, such as how much solar energy will be received and how much wind or rain will affect it. Another common factor, the topographic wetness index (TWI), is a calculation in digital elevation models of the tendency to accumulate water per slope and unit area, and is one of the most widely referenced hydrologic topographic factors, which helps explain the location of forest vegetation. Analyses of topographical factors can be calculated using a geographic information system (GIS) program based on digital elevation model (DEM) data. Recently, a large number of free open source software (FOSS) GIS programs are available and developed for researchers, industries, and governments. FOSS GIS programs provide opportunitiesfor flexible algorithms customized forspecific user needs. The majority of biodiversity in island areas exists at about 20% higher elevations than in land ecosystems, playing an important role in ecological processes and therefore of high ecological value. However, island areas are vulnerable to disturbances and damage, such as through climate change, environmental pollution, development, and human intervention, and lacks systematic investigation due to geographical limitations (e.g. remoteness; difficulty to access). More than 4,000 of Korea's islands are within a few hours of its coast, and 88% are uninhabited, with 52% of them forested. The forest ecosystems of islands have fewer encounters with human interaction than on land, and therefore most of the topographical conditions are formed naturally and affected more directly by weather conditions or the environment. Therefore, the analysis of forest topography in island areas can be done more precisely than on its land counterparts, and therefore has become a major focus of attention in Korea. This study is focused on calculating the performance of different topographical factors using FOSS GIS programs. The test area is the island forests in Korea's south and the DEM of the target area was processed with GRASS GIS and SAGA GIS. The final slopes and TWI maps were produced as comparisons of the differences between topographic factor calculations of each respective FOSS GIS program. Finally, the merits of each FOSS GIS program used to calculate the topographic factors is discussed.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.1
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• pp.45-52
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• 2019

This experiment was carried out to study the change of productivity and feed value in different types of hilly pasture. The pasture utilized in the experiment was placed on the experimental farm of Pyeongchang Campus of Seoul National University. Forage production type(FP; Orchardgrass 18 + Tall Fescue 12 + Timothy 5 + White clover 5 kg/ha) and Public farm type(PF: Orchardgrass 12 + Tall Fescue 18 + Timothy 5 + White clover 5 kg/ha) pasture were established in September 3, 2014 and utilized (cutting or grazing) four times every year. Growth characteristics, yield and forage quality were investigated for two years. Plant height of grasses was the highest in the $1^{st}$ cutting and legumes was in the $2^{nd}$ cutting. Dry matter (DM) content was highest at every the $1^{st}$ cut grasses significantly lower at the $2^{nd}$ harvest (p<0.05). However, there was no significant difference in the $2^{nd}$, $3^{rd}$ and $4^{th}$ harvest in 2016. In the botanical composition change, the portion of legume was gradually increased after pasture establishment and the ratio of weed and bare land was higher at $2^{nd}$ and $3^{rd}$ cutting, but it was decreased at $4^{th}$ harvest. There was no significant difference in 2016 of fresh yield between two farm types (p>0.05). The yield of dry matter showed similar trend of fresh yield and forage production type was higher than that of public farm type (p<0.05). The forage intake by livestock was 1,452 kg/ha in 2015 and 1,743 kg/ha in 2016. Pasture utilization ratio of public farm type pasture was highest in the $3^{rd}$ grazing time. Forage quality of pasture in relation to management type had not significant difference, but there was difference in harvest times. Crude protein (CP) was the lowest in the $1^{st}$ harvest and total digestible nutrient (TDN) was highest in the $1^{st}$ harvest and lowest in the $4^{th}$ harvest. Based on the above results, it is found that the establishment of pasture suitable for farm's situation is important for set up of Korean model of hilly pasture. Although the forage production type is superior on forage productivity, it is recommended that the results will be provided as basic data for management of public farm type in the future.

• (The)Study of the Eastern Classic
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• no.34
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• pp.63-88
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• 2009

This paper was a quest of pattern of holding "Dae Hak - the Great Learning" during Joseon Period having investigated the characteristics of the Essentials of the Studies of the Sages(聖學輯要, Seong Hak Jibyo) that was compiled by Lee I was a reinterpretation of the Great Learning, and also academic enrichment. During the period of Joseon Dynasty, the Great Learning had held the most important position as core scripture in the intellectual society that pursued Seong Hak(聖學, sage learning). Throughout the Joseon Period, the Great Learning was the essential text for the Emperorship Learning(帝王學, Jewang Hak) as well as Seong Hak, and it can also be said that Seong Hak Jibyo compiled by Yulgok - the courtesy name of Lee I, was the comprehensive collections thereof. While compiling Seong Hak Jibyo, Yulgok presented a model of Seong Hak of Joseon, which was based on "the Great Learning". Yul Gok organized the system of "Seong Hak Jibyo" largely in five parts, and properly arranged the Three Cardinal Principles(三綱領, samgangryeong) and Eight Articles or Steps(八條目, paljomok) therein. Particularly, in the Chapter Two, "Cultivating Oneself(修己, sugi)", Yulgok deal with 'being able to manifest one's bright virtue'(明明德, myeong myeong deok) among the Three Cardinal Principles as the core curriculum, meanwhile, Yulgok also covered "Investigation of things, gyeongmul(格物)," "Extension of knowledge, chiji(致知)," "Sincerity of the will, Seongui(誠意)," "Rectification of the mind, Jeongshim(正心)," "Cultivation of the personal life, susin(修身)," among Paljomok(eight steps) as the ultimate purpose of 'Stopping in perfect goodness'(止於至善, jieojiseon) These well preserve the principal system of Confucianism where "Cultivating oneself and regulating others (修己治人, sugichiin)" are core value, and his instructions as such also back up academic validity logically by presenting specific guidelines for practice according to each domain. Reinterpretation of "The Great Learning" by Yulgok in Seong Hak Jibyo is an arena to investigate the characteristics of Confucianism in Joseon Period, which was different from that of China, furthermore, such guidelines might take a role as criteria to understand the characteristics of humans and learning possessed by Korean people.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.451-468
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• 2021

Predicting hazardous ground conditions ahead of a TBM (Tunnel Boring Machine) tunnel face is essential for efficient and stable TBM advance. Although there have been several studies on the electrical resistivity survey method for TBM tunnelling, sufficient experimental data considering TBM advance were not established yet. Therefore, in this study, the laboratory-scale model experiments for simulating TBM excavation were carried out to analyze the applicability of an electrical resistivity survey for predicting hazardous ground conditions ahead of a TBM tunnel face. The trend of electrical resistivity during TBM advance was experimentally evaluated under various hazardous ground conditions (fault zone, seawater intruded zone, soil to rock transition zone, and rock to soil transition zone) ahead of a tunnel face. In the course of the experiments, a scale-down rock ground was provided using granite blocks to simulate the rock TBM tunnelling. Based on the experimental data, the electrical resistivity tends to decrease as the tunnel approaches the fault zone. While the seawater intruded zone follows a similar trend with the fault zone, the resistivity value of the seawater intrude zone decreased significantly compared to that of the fault zone. In case of the soil-to-rock transition zone, the electrical resistivity increases as the TBM approaches the rock with relatively high electrical resistivity. Conversely, in case of the rock-to-soil transition zone, the opposite trend was observed. That is, electrical resistivity decreases as the tunnel face approaches the rock with relatively low electrical resistivity. The experiment results represent that hazardous ground conditions (fault zone, seawater intruded zone, soil-to-rock transition zone, rock-to-soil transition zone) can be efficiently predicted by utilizing an electrical resistivity survey during TBM tunnelling.

• Journal of Korea Water Resources Association
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• v.56 no.6
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• pp.403-417
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• 2023

In this research, a methodology was developed for constructing an appropriate rainfall image database for estimating rainfall intensity based on CCTV video. The database was constructed in the Large-Scale Climate Environment Chamber of the Korea Conformity Laboratories, which can control variables with high irregularity and variability in real environments. 1,728 scenarios were designed under five different experimental conditions. 36 scenarios and a total of 97,200 frames were selected. Rain streaks were extracted using the k-nearest neighbor algorithm by calculating the difference between each image and the background. To prevent overfitting, data with pixel values greater than set threshold, compared to the average pixel value for each image, were selected. The area with maximum pixel variability was determined by shifting with every 10 pixels and set as a representative area (180×180) for the original image. After re-transforming to 120×120 size as an input data for convolutional neural networks model, image augmentation was progressed under unified shooting conditions. 92% of the data showed within the 10% absolute range of PBIAS. It is clear that the final results in this study have the potential to enhance the accuracy and efficacy of existing real-world CCTV systems with transfer learning.

• Asia Marketing Journal
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• v.13 no.4
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• pp.105-137
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• 2012

After relationship marketing emerged as a new approach in the marketing field in the 1980s, it has been widely studied in the United States, Europe and Asia. Rapid environmental changes and global competition has made it inevitable for companies to consider their relationships with the environment more closely. Under these circumstances, relationship marketing has held a position as a pivotal paradigm in the field of strategy as well as in marketing. In addition, relationship marketing has overcome the limitations of a traditional marketing research while providing richer implications in company's marketing activities. The paradigm shift to relationship marketing has brought fundamental changes in a marketing point of view. First, in philosophical aspects, unlike past research which focused solely on customer satisfaction, organizational relationship parameters which focuses on trust and commitment has become key elements of successful relationship marketing while shifts in thoughts naturally take place from adaptive marketing to strategic marketing. Second, in structural aspects, the relational mechanism of governance such as network structure with a variety of relational partners has emerged as a new marketing organization from the previous simple structure focusing on the micro-economic, marketbased trading between seller and customer. Third, in behavioral aspects, it proposed the strategic course of the action of gaining an advantage over the competition on the individual firm level by focusing on building long-term relationships and considering partnership with the components in the entire marketing system, rather than with one-time transaction-centric action between a seller and a customer. Fourth, in the aspects of marketing performance, marketing performance was sought through the long-term and cooperative relationship with various stakeholders, including customers in the marketing system, focusing on the overall competitive advantage based on relationship rather than individual performance of individual companies' marketing activities, such as market share and customer satisfaction. However, studies of relationship marketing were mostly centered in interorganizational relationships focusing on the relational structure and properties of commercial sector in the marketing system. Paradoxically, the circumstance of the consumer's side that must be considered is evolving again in relationship marketing. In structural aspects, a community, as the new relationship governance structure in the digital environment, and in behavioral aspects, the changing role of consumer participation demanding big changes in the digital environment engaged in the marketing system. The possibility of building a relationship marketing community for common value creation is presented in terms of organization of consumers with the focus on changing marketing environment and marketing system according to the new realities of the 21st century- the popularity of digital environments and the diffusion of customer participation. Therefore, future research of relationship marketing must seek for a truly integrated model including all of the existing structure and properties of the research oriented relationship from both the commercial and consumer sector.

• Journal of Industrial Convergence
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• v.22 no.1
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• pp.149-162
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• 2024

This study is a longitudinal study of female older adults living alone, one of the most vulnerable groups in our society, to determine how their depression changes over time and what factors affect their depression. At the same time, considering that there is a large difference in age among the same older adults, this study divided the female older adults into the young-old and the old-old to see how the predictors of depression in each group differ from each other. The main findings are as follows First, depression among female older adults living alone appears to have a declining pattern over time. In the conditional model, factors affecting the initial level of the depression trajectory among women living alone were found to be associated with lower initial depression values among those living in metropolitan areas rather than non-metropolitan areas, better subjective health, and those who did not exercise. Next, we examined the factors affecting rate of change (slope) in depression among female living alone older adults and found that the higher the age, the larger the metropolitan area, the better the subjective health, the less socializing, and the more socializing, the greater the decrease in depression level. Finally, there were some differences in the pathways affecting the initial value and slope of depression among female older adults living alone between the early and late older adults. Specifically, the higher the initial level of participation in social activities, the greater the change in depression among the late older adults, while there was no significant relationship among the early older adults. In the early older adults, better initial subjective health was associated with a larger change in depression than in the late older adults. Only in the late older adults did those who regularly exercised in the early years have higher initial depression values than those who did not. Based on the results of the above analyses, suggestions were made to reduce depression among female older adults living alone.