• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.34 no.1
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• pp.21-29
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• 2023

This paper reviews the global effect of the coronavirus disease 2019 (COVID-19) pandemic on the mental health of children and adolescents in South Korea, the U.S., Japan, and China. We reviewed research on deteriorated mental health, including increased suicide, suicidal thoughts, and self-harm. Various studies have shown that students' mental health issues, such as depression and anxiety, have worsened during the COVID-19 pandemic. Furthermore, the number of students who committed suicide has significantly increased in the U.S. and Japan. Factors such as prior mental health status, change in daily routine, reduced physical activity, excessive screen time, overuse of electronic devices, and reduced social support have been reported to have a significant effect. The chain of deteriorating mental health among the youth began at the onset of COVID-19, social distancing, and school closure. As youths began to stay at home instead of going to school, they lost opportunities to connect with their friends or teachers, who could provide support outside of their homes. Young people spent less time on physical activity and more time online, which damaged their sleeping schedule and daily routine. In preparing for the post-pandemic phase, we should thoroughly analyze the long-term effects of the pandemic on youth mental health, while simultaneously tackling current imminent issues.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.349-349
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• 2023

In recent years, urban floods have become more frequent, causing significant harm to society and resulting in substantial losses to the national economy and people's lives and property. To assess the impact of floods on people's safety and property in Seoul, annual precipitation data from 1980 to 2020 was analyzed for return periods of 5, 10, 20, 50, and 100 years. A rainfall runoff simulation model for Seoul was established using HEC-HMS and HEC-RAS models. The study revealed that at a 5-year return period, water began to accumulate in Seoul, but it was not severe. However, at a 10-year return period, the water accumulation was relatively serious, and inundation began to occur. At a 20-year return period, there was serious water accumulation and inundation in Seoul. During a 50-year return period, Seoul suffered from severe inundation in commercial areas, resulting in substantial losses to the local economy. The findings indicate that Seoul City faces high flood risks, and measures should be taken to mitigate the impact of floods on the city's residents and economy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.524-526
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• 2021

As the invention of automobiles and construction of roads for vehicles began, the occurrence of traffic accidents began to increase. Accordingly, efforts were made to prevent traffic accidents by changing the road construction method and using signal systems such as traffic lights, but until now, numerous human and property damages have occurred every year due to traffic accidents caused by freezing of the road due to bad weather. In this paper, we propose a method of transmitting ice detection data detected using vehicle sensor data to vehicle navigation to reduce traffic accidents caused by road freezing.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.521-523
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• 2021

As the invention of automobiles and construction of roads for vehicles began, the occurrence of traffic accidents began to increase. Accordingly, efforts were made to prevent traffic accidents by changing the road construction method and using signal systems such as traffic lights, but even today, numerous human and property damages have occurred due to traffic accidents caused by freezing of the road due to bad weather. In this paper, in order to reduce traffic accidents due to road freezing, we propose a method of transferring the ice detection information obtained by deep learning of infrared wavelength data obtained using an infrared camera to the vehicle's navigation.

• Strategy21
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• s.30
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• pp.31-62
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• 2012

It is a commons sense that the Republic of Korea is a maritime state that depends its survival on International Trade and International Economy. Korea was a peninsula and do it can be both maritime and continental state by its choice. However, after the national division in 1945, South Korea had became a virtual island and pursue a maritime way for national development in the past 60 plus years. Now, South Korea is becoming a world's 12 th largest major trading and maritime state. South Korea has far more ships per capita than any other nations in the world and its economy is heavily depend upon the imports and exports with other nations in the world that pass through the oceans. Therefore, the Koreans regard the security of the sea lanes of communication as vital to the survival of the nation. The SLOC is the life line for Republic of Korea. Since the early 1990s, immediately after the Cold War was over, South Koreans began to recognize the importance of Sea Routes and thus began to build a navy that can handle with the new problems of the post Cold War era. However, the maritime security environments of the Republic of Korea today is shaky and dangerous. Almost every water near the Korean peninsula, some kind of international confrontations are going on. Territorial disputes on Dok do, Senkaku, Scarbrough, Shisha, Nansha and Eodo between and among Korea, Japan, China, Taiwan, Phillipines, Indonesia and Vietnam are the examples. In this essay, the author argues that the S. Korean efforts and capabilities to deal with these challenges are not enough and exhorts more efforts and more powerful navy for the Korean people.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.2
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• pp.153-168
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• 2024

Morphological and skeletal development in the cultured threeline grunt Parapristipoma trilineatum was studied from 1.96 to 61.39 mm notochord length (NL) or standard length (SL) specimens (n=360). After two days post-hatching (dph, 2.13 mm NL), the mouth opened, and melanophores formed in the eyes and egg yolk were absorbed. Oli globules were absorbed at 3 dph (2.71 mm NL). The total number of fin rays reached that of adults at 28 dph (10.58 mm SL). During skeletal development, the premaxillaray, dentary, opercle, preopercle, and cleithrum first began to ossify at 6 dph (3.51 mm NL). Ossification of all skeletal elements was completed at 28 dph (14.57 mm SL). The vertebrae began to ossify at 17 dph (5.63 mm SL) and were completed at 28 dph (8.48 mm SL), progressing from cranium to caudal bone. The centrum ossified from the dorsal to ventral direction. Vertebral fusion and separation were found to be common skeletal abnormalities.

• Imaging Science in Dentistry
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• v.30 no.1
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• pp.33-48
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• 2000

Purpose : To investigate osseointergration of titanium implants into the tibia of rabbits, which were fed a low calcium diet and irradiated. Materials and Methods : To prepare the experimental model, control group was fed a normal diet and experimental group was fed a low calcium diet for 4 weeks. And then, titanium implants were inserted into the tibia of each rabbit. Experimental group was subdivided into two groups; low calcium diet/non-irradiation group and low calcium diet/irradiation group. The low calcium diet/irradiation group was irradiated with a single absorbed dose of 15 Gy at the 5th postoperative day. At 12, 19, 33, 47, and 61 days after implantation (1, 2, 4, 6, and 8 weeks after irradiation), the bone formation in the bone-implant interface area was examined by light microscopy and fluorescent microscopy. Results and Conclusions: 1. In the control group, there began to form woven bone in the bone-implant interface area at 12 days after implantation. As the experimental time was going on, the amount of bone which was in contact with the implant was increased. 2. In the low calcium diet/non-irradiation group, there began to form woven bone in the bone-implant interface area at 19 days after implantation. Although the amount of bone which was in contact with the implant was increased as the experimental time was going on, the extent of increased bone was weak as compared with control group. 3. In the low calcium diet/irradiation group, there began to form woven bone incompletely in the bone-implant interface area at 19 days after implantation, but there were vascular connective tissues in the bone-implant interface area over the entire experimental period. 4. In the control group and low calcium diet/non-irradiation group, bone labeling bands were observed at 33 days after implantation, which suggests that the bone formation and remodeling was in process, but interstitial bone remodeling was not observed in the low calcium diet/irradiation group.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.3
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• pp.284-288
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• 2018

The scuttle fly central nervous system (CNS) is unobservable during egg and larvae instar stage 1. During days 2~3 of larvae instar stage 2, the left and right hemisphere of the brain can be observed. Below the brain, the subesophageal ganglion (SOG) connects to the ventral nerve cord (VNC). During days 3~5 of larvae instar stage 3, the CNS enlarged slightly with no other changes. During days 1~3 of the pupal stage the CNS moved to the head with no distinguishable changes from the previous stage. During days 4~6 of the pupal stage, the left and right hemisphere of the brain had fused into one mass and the optic lobe (OL) located on the side of the brain completed its development. During days 7~9 of the pupal stage, the OL began to show eyeball pigment. The SOG was connected to the brain and the VNC began to separate, which was accompanied by an increase in nerve fibers. During days 10~12 of the pupal stage, the brain of the CNS and VNC was clearly distinguished and the brown pigmentation of OL became darker. During days 13~15 days of the pupal stage, the separated brain and VNC became connected by thin nerve fiber. The VNC began to separate into two with a greater increase in nerve fibers. The adult fly showed similar features to the previous stage, but the brain was located in the head and the VNC in the chest.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.1
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• pp.41-55
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• 1991

A study was done to investigate characteristics of the land and sea breeze over Cheju island on the basis of surface meteorological data collected from 1977 to 1986. The results are summarized as follows: The frequency of the land and sea breze was highest in August followed by September, October, May and November in descending order. This indicates that the frequency of the land and sea breeze is higher in fall than in spring, and lowest in winter. The sea breeze began much earlier than any other regions of Korea all the year round, and it began about 30 minutes earlier and ended one hour later in the northern coast than in the southern coast of Cheju island. Meanwhile, the land breeze began about one hour earlier in the southern coast than in the northern coast and ended almost at the same time in both coasts. The annual mean duration of the sea breeze was about one hour longer in the northern coast than in the southern coast, but the land breeze showed an opposite trend. The duration of the sea breeze was longer in summer than in winter and again the land breeze was opposite. Transition period from the sea to the land breeze was relatively long in summer and shout in winter, but transition period from the land to the sea breeze was not different between seasons. The time for a maximum velocity of the sea breeze came earlier in the southern coast than in the northern coast, but that of the land breeze came almost at the same time in both coasts with no seasonal variations. Monthly mean maximum velocity of the sea breeze was greater than that of the land breeze.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.243-252
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• 1985

The mechanism of reproductive cycle of longchin goby Chasmichthys dolichognathus was investigated for the annual variations of gonadosomatic index(GSI), histological changes of gonad, reproductive cycle, and initiating and terminating factors of the breeding season. The experimental fish were captured in the tide pool of Tongbaeksom, Pusan, Korea from February 1983 to September 1984. Experimental fish for the study of initiating and terminating factors of the breeding season were maintained in filtered recirculating aquariums and exposed to various temperature and photoperiod regimes. The ovary is a pair of sac-shaped organ, and the testicular structure is tubular and it is connected to the seminal vesicle which is located at the posterior end of the testis. GSI began to increase from February when the water temperature began to increase and reached peak in April. It began to decrease from August, the top water temperature season, and maintained relatively low values until January. The annual reproductive cycle includes successive six developmental stages : early growing from December to February, late growing from January to March, early mature from February to May, late mature and ripe from March to August, spawning from April to July, degeneration and resting stage from May to December. An experimental study based on the reproductive cycle of this species indicated that rising temperature under long photoperiod during spring stimulated gonadal maturation, whereas terminating factor of the breeding season with recrudescence of the gonads was demonstrated as high water temperature during summer regardless of photoperiod.