• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.293-301
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• 2019

The experiment was conducted to determine the performance of DME combustion gas when used as a fuel for DME burner for raising temperature and $CO_2$ concentration in greenhouse and also to examine its effects on chlorophyll content, and fresh and dry weight of lettuce and Chinese cabbage. DME-1 and DME-2 treatments consisted of average DME flow quantity in duct were $17.4m^3min^{-1}$ and $10.2m^3min^{-1}$ respectively to greenhouse-1 and greenhouse-2 and no DME gas was supplied to greenhouse-3 which was left as control (DME-3). DME supply times were $0.5hr\;day^{-1}$, $1hr\;day^{-1}$, $1:30hrs\;day^{-1}$ and $2hrs\;day^{-1}$ on week 1, 2, 3, and 4 respectively. Chlorophyll content and fresh and dry weight of lettuce and Chinese cabbage were measured for each treatment and analyzed through analysis of variance with a significance level of P<0.05. The result of the study showed that $CO_2$ concentration increased up to 265% and 174% and the level of temperature elevated $4.8^{\circ}C$ and $3.1^{\circ}C$ in greenhouse-1 and 2, respectively as compared to greenhouse-3 due to application of DME combustion gas. Although, the same crop management practices were provided in greenhouse-1, 2 and 3 at a same rate, the highest change (p<0.05) of chlorophyll content, fresh weight and dry weight were found from the DME-1 treatment, followed by DME-2. As a result, DME combustion gas that raised the level of temperature and $CO_2$ concentration in the greenhouse-1 and greenhouse-2, might have an effect on growth of lettuce and Chinese cabbage. At end of experiment, the highest fresh and dry weight of lettuce and Chinese cabbage were measured in greenhouse-1 and followed by greenhouse-2. Similarly chlorophyll content of greenhouse-1 and greenhouse-2 were more compared to greenhouse-3. In general, DME was not producing any harmful gas during its combustion period, therefore it can be used as an alternative to conventional fuel such as diesel and liquefied petroleum gas (LPG) for both heating and $CO_2$ supply in winter season. Moreover, endorsed quantify of DME combustion gas for a specified crop can be applied to greenhouse to improve the plant growth and enhance yield.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.258-267
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• 2020

The agrivoltaic can produce electricity and grow crops on fields at the same time. It is necessary to analyze the cultivation environment and evaluate the crop productivity under agrivoltaic because the shading point changes according to structure of agrivoltaic and sun's position. Two types of "fixing" and "tracing" agrivoltaic were installed, and a rice cultivation experiment was conducted in the fields under each agrivoltaic and without shading (control). "Hyunpoombyeo" was transplanted on June 7, 2019, and grown with fertilization of 9.0-4.5-5.7 kg/10a (N-P-K). Fifteen weather stations were installed under each agrivoltaic to measure solar radiation and temperature, and yield and yield-related elements were investigated by points. The accumulated solar radiation during the rice growing season in fixing was no much difference between points, and that in tracing was much difference between points. However, the average solar radiations of two agrivoltaics were similar. The mean temperature, yield, and yield-related elements showed a significant difference for the shading rate, and decreased with increasing the shading rate except ripening grain rate and 1000 grain weight of fixing agrivoltaic. In the relationship between shading rate and yield, fixing and tracing were fitted to a logistic equation and a simple linear equation, respectively, and showed a high correlation (tracing: R2 = 0.62, fixing: R2 = 0.73). The shading rate variation by point for two types was large despite similar yield variation. Thus, it needs to be more closely examined the relationship of the shading rate for a specific period rather than the shading rate during the whole growing season.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.1
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• pp.15-29
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• 2021

In the Arctic Ocean, the distribution of sea ice and ice sheets changes as climate changes. Because the distribution of ice cover influences the mineral composition of marine sediments, studying marine sediments transported by sea ice or iceberg is very important to understand the global climate change. This study analyzes marine sediment samples collected from the Arctic Ocean and infers the provenance of the sediments to reconstruct the paleoenvironment changes of the western Arctic. The analyzed samples include four gravity cores collected from the Araon mound in the Chukchi Plateau and one gravity core collected from the slope between the Araon mounds. The core sediments were brown, gray, and greenish gray, each of which corresponds to the characteristic color of sediments deposited during the interglacial/glacial cycle in the western Arctic Ocean. We divide the core sediments into three units based on the analysis of bulk mineral composition, clay mineral composition, and Ice Rafted Debris (IRD) as well as comparison with previous study results. Unit 3 sediments, deposited during the last glacial maximum, were transported by sea ice and currents after the sediments of the Kolyma and Indigirka Rivers were deposited on the continental shelf of the East Siberian Sea. Unit 2 sediments, deposited during the deglacial period, were from the Kolyma and Indigirka Rivers flowing into the East Siberian Sea as well as from the Mackenzie River and the Canadian Archipelago flowing into the Beaufort Sea. Unit 2 sediments also contained an extensive amount of IRD, which originated from the melted Laurentide Ice Sheet. During the interglacial stage, fine-grained sediments of Unit 1 were transported by sea ice and currents from Northern Canada and the East Siberian Sea, but coarse-grained sediments were derived by sea ice from the Canadian Archipelago.

• Korean Journal of Heritage: History & Science
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• v.53 no.4
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• pp.250-273
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• 2020

The three-story stone pagodas in Hyeon-ri and Hwacheon-ri,Yeongyang Gyeongsangbuk-do are stone pagodas that exhibit the typical style of Unified Silla. The two pagodas are believed to have been built in the mid- and late 9th centuries at the latest, considering the style of the three-story roof stone on top of the double-tier base. This is also confirmed by the reliefs carved at the base and the first-story of the pagoda. The Four Heavenly Kings and the Twelve Zodiacal Animal Deities were first combined in the late 8th century in the stone pagoda at the Wonwonsa Temple Site, and the Eight Classes of Divine Beings was also the most popular carved pagoda reliefs in the 9th century. However, the two Yeongyang stone pagodas are characterized by a combination of the Four Heavenly Kings (1st story), the Eight Classes (top base), and the Twelve Zodiacal Animals (lower base), and the stone used for the pagoda consists of sedimentary rocks of the sandstone family, which comprise most of the geological strata in the Yeongyang area, rather than ordinary granite. The new combinations of the three types of guardian deities and the Eight Classes changed from seated to standing poses is interpreted as an attempt to enhance the Buddhist faith and cultural status of the Yeongyang area, along with the fact that the stone pagoda was built using local natural materials. The Eight Classes of the Yeongyang stone pagoda does not follow the two types of arrangement of the pagodas with the Eight Classes, but some of the deities have been relocated to a new location. Composed of AsuraGandharva on the east side, Naga-Mahoraga on the south, Deva-Garuda on the west, and Kimnara-Yaksa on the north, this form can be classified as a unique 'third layout of the Eight Classes' in the Yeongyang area. Such changes in the shape and posture of the reliefs reflect a new perception of the pagodas. The reason why the Gandharva and Yaksa statues were carved on the east and north sides, respectively, was because they were deemed subordinate to the Four Heavenly Kings, and the fact that the Naga and the Mahoraga were carved on the south side was presumed to have influenced the geographical location of the two pagodas on the northern side of Banbyeoncheon Stream. The Hyeon-ri and Hwacheon-ri three-story stone pagodas inherited the tradition of typical Unified Silla-period pagodas, while also bearing their own new regional characteristics.

• Journal of Korea Water Resources Association
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• v.53 no.12
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• pp.1159-1172
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• 2020

This study applied deep convolution neural network based on U-Net and SegNet using long period weather radar data to very short-term rainfall prediction. And the results were compared and evaluated with the translation model. For training and validation of deep neural network, Mt. Gwanak and Mt. Gwangdeoksan radar data were collected from 2010 to 2016 and converted to a gray-scale image file in an HDF5 format with a 1km spatial resolution. The deep neural network model was trained to predict precipitation after 10 minutes by using the four consecutive radar image data, and the recursive method of repeating forecasts was applied to carry out lead time 60 minutes with the pretrained deep neural network model. To evaluate the performance of deep neural network prediction model, 24 rain cases in 2017 were forecast for rainfall up to 60 minutes in advance. As a result of evaluating the predicted performance by calculating the mean absolute error (MAE) and critical success index (CSI) at the threshold of 0.1, 1, and 5 mm/hr, the deep neural network model showed better performance in the case of rainfall threshold of 0.1, 1 mm/hr in terms of MAE, and showed better performance than the translation model for lead time 50 minutes in terms of CSI. In particular, although the deep neural network prediction model performed generally better than the translation model for weak rainfall of 5 mm/hr or less, the deep neural network prediction model had limitations in predicting distinct precipitation characteristics of high intensity as a result of the evaluation of threshold of 5 mm/hr. The longer lead time, the spatial smoothness increase with lead time thereby reducing the accuracy of rainfall prediction The translation model turned out to be superior in predicting the exceedance of higher intensity thresholds (> 5 mm/hr) because it preserves distinct precipitation characteristics, but the rainfall position tends to shift incorrectly. This study are expected to be helpful for the improvement of radar rainfall prediction model using deep neural networks in the future. In addition, the massive weather radar data established in this study will be provided through open repositories for future use in subsequent studies.

• Ecology and Resilient Infrastructure
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• v.7 no.4
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• pp.388-395
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• 2020

Exotic species have been imported for economic purposes, but more recently, an increasing number of animals are imported as pets. With the increasing popularity of two species of turtles, Mauremys sinensis and Pseudemys concinna, the number of pet turtle owners has gradually increased since 2014. The number of turtles increased by 180 in 2017 and 281 in 2019. However, these turtle species have been abandoned to nature, owing to their long lifespans and the changes in conditions of pet owners. The two turtle species have been designated as invasive alien species (AIS) in Korea considering their ecological risks, and the Biological Diversity Act prohibits their release. The owners of Mauremys sinensis and Pseudemys concinna are required to submit the "Application for Approval of Breeding and Grace for AIS" document. In this study, the breeding conditions for the two turtle species were investigated by analyzing the information in the submitted applications for six months (e.g., the suitability of breeding facilities, number of turtles, breeding period, type of pet adoption, and local district of pet owner). A total of 614 cases were analyzed. Because only 58% of breeders provided suitable breeding conditions, breeding information and responsible pet ownership training should be offered to prevent abandonment in natural ecosystems. In addition, continuous monitoring is necessary to prepare for potential problems caused by the lack of information in many applications and the one-off licensing policy.

• Journal of The Korean Society of Clinical Toxicology
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• v.18 no.2
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• pp.57-65
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• 2020

Purpose: Since 2012, acetaminophen can be accessed easily not only at pharmacies but also at convenience stores. The relationship between the easy access of acetaminophen and the risk of poisoning has been controversial. Several studies also reported different results regarding the risk of acetaminophen poisoning after access to acetaminophen was relaxed. This study examined the long-term effects on the risk of acetaminophen poisoning after easy access to acetaminophen was implemented. Methods: This was a retrospective analysis of an emergency department (ED)-based in-depth Injury Surveillance Cohort by the Korea Center for Disease Control and prevention from 2011 to 2018. Poisoning cases were selected from the Cohort, and the incidence of acetaminophen poisoning and the characteristics of the cases of acetaminophen poisoning were analyzed. The purchase path and the amount of ingestion in acetaminophen poisoning were sub-analyzed from data of six EDs. Results: Of 57,326 poisoning cases, 4.0% (2,272 cases) were acetaminophen poisoning. Of 2,272 cases of acetaminophen poisoning, 42.8% (974 cases) required in-patient care after ED management. Two hundred and sixty-four of these 964 cases required intensive care. The rates of cases that required in-patient treatment and the rates of cases that required intensive care increased from 29.4% in 2011 to 48.1% in 2018, and from 3.1% in 2011 to 15.2% in 2018, respectively (p<0.001, p<0.001). In the poisoning group with in-depth toxic surveillance (n=15,908), the incidence and proportion of acetaminophen (AAP) poisoning increased from 55 cases per year to 187 cases per year and 4.9% to 6.1%, respectively (p=0.009, p<0.001, respectively). The most common age group of acetaminophen poisoning was teenagers, which is different from the most common age group of other pharmaceutical agents: the middle age group of 40-49 years (p<0.001). Of 15,908 in-depth toxic surveillance patients, 693 patients had AAP poisoning, of whom 377 cases (54.2%) purchased acetaminophen from a non-pharmacy. The proportions of the purchase path from non-pharmacy were 41.4% at 2011-12 and 56.4% (2013-18) (p=0.004). The amount of acetaminophen ingestion was 13.5±14.3 g at 2011-12 and 13.9±15.1 g at 2013-18 (p=0.794). Conclusion: Although the incidence of acetaminophen poisoning did not increase remarkably in the short term after the implementation of the new regulation, the incidence of acetaminophen poisoning has increased slightly during the study period of 2017-18. In addition, the proportion of the purchase path from non-pharmacies has increased since the emergence of new regulations for the easy access of acetaminophen in 2012. The incidence of acetaminophen poisoning might have been affected after the increasing accessibility of acetaminophen in convenience stores. Continuous control of acetaminophen poisoning is required. Furthermore, the prevention of acetaminophen poisoning should be focused on teenagers with specialized school education programs.

• Korean Journal of Heritage: History & Science
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• v.54 no.2
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• pp.4-21
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• 2021

A stone mold from the Sabi period of Baekje was excavated at the western tombs in Neungsan-ri, Buyeo where there was a recent excavation survey (2016). It was believed and reported that such stone molds were used for copper needles during the early Iron Age; however, a close re-examination of the form revealed that they were used for bifid ornamental hairpins. Given its casting form, the stone mold of Neungsan-ri is estimated to have been used to make bifid ornamental hairpins in a ∩ shape, narrowing down toward the tip. It is considered an artifact of the Goryeo dynasty. The stone used to make the bifid ornamental hairpin mold of Neungsan-ri was chlorite-schist, the principal minerals of which include chlorite, amphibole, and talc. Similar rocks are in nearby Buyeo (Oesan-myeon), Cheongyang, Gongju, and Yesan. They are mainly found between Jiseon-ri, Oesan-myeon, Buyeo, Sucheol-ri, Yesane-up, and Yesan. Nearly 70 bifid ornamental hairpins from the Goryeo dynasty were excavated at Neungsan-ri, Buyeo and the surrounding areas. Among them, the bronze ones excavated from the tombs of Songguk-ri, Buyeo are estimated to have been made using this mold as they closely resemble the Neungsan-ri mold. Stone was likely the preferred material for molds to make bronze artifacts as it was easy to sink a die. Regarding the bifid ornamental hairpin cast excavated in Neungsan-ri, they obtained stones in nearby areas 20~50km from their location, made bronze artifacts, and distributed them to nearby sites during the Goryeo dynasty. These artifacts suggest that the casting technology of using a stone mold was still employed then.

• Journal of fish pathology
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• v.34 no.1
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• pp.71-80
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• 2021

Cephalexin, a semi-synthetic cephalosporin antibiotic, has long been used in fish aquaculture in various countries under legal authorization. The drug is thus widely available for use in other aquatic species except fishes like the crustacean whiteleg shrimp. This study aims to develop a sensitive method for laboratory residue studies to adopt in withdrawal period determinations. Through repeated trials from the existing methods developed for other food animal tissues, it was possible to achieve a sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method. The results showed that at a concentration of 0.1 mg/kg, the recovery rate was 81.79%, and C.V. value was 8.2%, which meet the recovery rate and C.V. recommended by Codex guideline. After satisfactory validation of analytical procedures, applicability to the shrimp tissue was confirmed in experimentally cephalexin-treated whiteleg shrimp. As a result, most muscle samples were detected below the limit of quantification (0.05 mg/kg) after day 3, and most hepatopancreas samples were detected below the limit of quantification after day 14. In particular, the limit of quantification 0.05 ppm with the presently developed method suggests sufficient sensitive over the current legal maximum residue limit of 0.2 mg/kg set for fishes.

• Journal of Korean Society of Forest Science
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• v.100 no.3
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• pp.423-431
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• 2011

The changes of forest degradation in North Korea have closely been related to political, economic and social conditions at all different times. The deforestation by local people for their livelihood has been accelerated when the recession has been worsened due to the 1990's collapse of socialism and the years of natural disasters, and the fall of the centralized and planned economy system. The serious recession in the 1990's has brought many changes in the North Korean society since the 2000's. Not only the underground economy, but also the market in which personal trades are occurred have been expanded as the distribution system of the planned economy system had fallen. In addition, even many state institutions have also increased timber harvest for export to acquire insufficient foreign currency. Eventually, North Korea felt the limits of utilization of forest resources under socialism then started to seek measures to restore devastated forest, while realizing the need of support from the international society. Therefore, some NGOs of South Korea started to give financial support on building tree nurseries in which seedlings for planting are produced to help the rehabilitation of the degraded forests in North Korea. Therefore, Planning of the basic directions for forest rehabilitation programs considering to economic and social conditions of North Korea are needed based on the successful rehabilitation experience of South Korea in the 1970's. First of all, relationships which was built after collapse of centrally planned economy between districts, businesses and workers must be consider to rehabilitate forests in North Korea. Secondly, due to the nature of forest rehabilitation projects this is very needs voluntary participation of resident for a long time, and then forest rehabilitation projects can create jobs for local resident, they can obtain continuous income on the forest rehabilitation projects field in order to promote resident's work in forest rehabilitation projects. Thirdly, the rate dependence on forests of the residents living must keep the level down by rural development projects going side by side with forest rehabilitation projects. Fourthly, use of exsisting forest management system in North Korea is also needed to ensure administrative power and labor for grand scale plantations in a short period of time. Meanwhile after the success of Forest Rehabilitation, it is very important to improve exsisting forest management system.