• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.1
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• pp.74-81
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• 2024

In the near future, autonomous ships, ships controlled by shore remote control centers, and ships operated by navigators will coexist and operate the sea together. In the advent of this situation, a method is required to evaluate the safety of the maritime traffic environment. Therefore, in this study, a plan to evaluate the safety of navigation through ship control simulation was proposed in a maritime environment, where ships directly controlled by navigators and autonomous ships coexisted, using autonomous operation technology. Own ship was designed to have autonomous operational functions by learning the MMG model based on the six-DOF motion with the PPO algorithm, an in-depth reinforcement learning technique. The target ship constructed maritime traffic modeling data based on the maritime traffic data of the sea area to be evaluated and designed autonomous operational functions to be implemented in a simulation space. A numerical model was established by collecting date on tide, wave, current, and wind from the maritime meteorological database. A maritime meteorology model was created based on this and designed to reproduce maritime meteorology on the simulator. Finally, the safety evaluation proposed a system that enabled the risk of collision through vessel traffic flow simulation in ship control simulation while maintaining the existing evaluation method.

• Korean Journal of Optics and Photonics
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• v.35 no.4
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• pp.150-156
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• 2024

One of the key factors in research regarding long-distance laser beam propagation, as in free-space optical communication or laser power transmission, is the transmission efficiency of the laser beam. As a way to improve efficiency, we perform extensive numerical simulations of the effect of modifying the laser beam's profile, especially replacing the fundamental Gaussian beam with a super-Gaussian beam. Numerical simulations of the transmitted power in the ideal diffraction-limited beam diameter determined by the optical system of the transmitter, after about 1-km propagation, reveal that the second-order super-Gaussian beam can yield superior performance to that of the fundamental Gaussian beam, in both single-channel and coherently combined multi-channel laser transmitters. The improvement of the transmission efficiency for a 1-km propagation distance when using a second-order super-Gaussian beam, in comparison with a fundamental Gaussian beam, is estimated at over 1.2% in the singlechannel laser transmitter, and over 4.2% and over 4.6% in coherently combined 3- and 7-channel laser transmitters, respectively. For a range of the propagation distance varying from 750 to 1,250 m, the improvement in transmission efficiency by use of the second-order super-Gaussian beam is estimated at over 1.2% in the single-channel laser transmitter, and over 4.1% and over 4.0% in the coherently combined 3- and 7-channel laser transmitters, respectively. These simulation results will pave the way for future advances in the generation of higher-order super-Gaussian beams and the development of long-distance optical energy-transfer technology.

• Journal of the Korean Society for Library and Information Science
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• v.20
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• pp.65-125
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• 1991

The study has tried to analize and appraise how did public library system under the Japanese imperialism affect the establishment and managemant of Korean public libraries. To achieve the purpose of the above-mentioned study, the contents of $\ulcorner$Japanese library statute$\lrcorner$ under Japanese imperialism and the current $\ulcorner$Korean library law$\lrcorner$ have been mutually compared, at the same time, the vestiage of Japanese imperialism in view of the establishment, personnel administration and reading systems have been concretely investigated, analyzed and compared. The conclusions obtained from the above are as followings. 1. In those days of the Korean Liberation, the situation of Korean public libraries was such as it under the Japanese rule and so, their names were only changed. However, as a part of its independent activities, the national library have once carried out the various programs such as the training of professional librarians, the establishment of the new classification schedule and the chief Librarian and deputy Librarian from the professional librarians in the office regulations, and they were well worth being the good examples for today's Korean library circle. Though the Goverment of the Republic of Korea had been formally established, the situation of the library circle was very dull owing to the Korean war for a long time. In 1963, $\ulcorner$The Korean library law$\lrcorner$ was promulgated, but the establishment of public libraries did not give satisfactory results because of the institutional fragility. In the 1980's the importance of library was embossed from the viewpoint of life-long education and the number of libraries was increased. However, there were still the remaining vestiges of Japanese library system in the practical library services. 2. After the Korean Liberation, the influnces of public library system under the Japanese imperialism showed in the office regulation of national library and the Korea library Law were also in the legal mechanism. In particular, the regulations of $\ulcorner$The staff-member of public library$\lrcorner$ and $\ulcorner$Admission fee of public library$\lrcorner$ including the chief librarian have referred to the library system under the Japanese imperialism since the liberation day to date. 3. At that time of the Korean Liberation, the U.S.Military Government Office had decided that the public library administration should be attached to the administration of local and internal affairs in accordance with the Japanese administative system. As a result, the public libraries had been forced to be indirectly affected by public library system under the Japanese imperialism for twenty years since the Liberation. 4. Since the Liberation, the personnel adminstration of public library has been so far on the steps of model under the Japanese imperialism. As the result of the field survey, the position standards of local chief librarians, non-professional character, the extra post system and the preponderant appointment of non-professional offices have analyzed by the influence of Public library system under the Japanese imperialism. Therefore, the Government authorities-concerned must readjust the standards of qualification and the divided duties corresponding to the position of public library staff members and to stipulate expressly in the revised library law. In addition, the regulation of the admission fee should be also actively detected for the free adminssion of library users. 5. Since the Liberation Day, the reading methods of public library have been so far similar to reading method under the Japaness imperialism. For example, the admission fee levied, the complicated procedures of using books including entrance and exit of a library, no-admission system, the limited lending books, the deposit system of outdoor lending books and the surety liable jointly and severally are originally caused by bureaucracy of under the Japanese imperialism. Therefore, the public libraries should make an offer space and opportunities which can enjoy freedom to the gull in future. The procedures and standards of library users will be simplified, if possible. As the above-mentioned, the actual conditions of Korean public libraries have been examined and analyzed. As the result of it, there are still the remaining vestiges of public library system under the Japanese imperialism in the establishment and management of the nation-wide public libraries. Such the remnants are an obstacle to the democratic development of public libraries and so, the authorities-concerned should take the proper-measures as soon as possible.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.6
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• pp.86-97
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• 2015

"The Jayeon Madang Development Project("JMDP")" is a project being promoted by the Ministry of Environment to create a cultural space and a natural rest area within the city. Abuksan, located at Abuksan in Gyeongsangnam-do Miryang-si Naeil-dong, has suffered a substantial amount of environmental degradation over time, so the need for ecological restoration made it a natural choice for the location of the JMDP's site. The purpose of this study is to examine ecological restoration design strategies used in Abuksan as part of the JMDP using system dynamics. The national archery center, hole, and arable land sites are key restoration areas in Abuksan that have faced with ecological problems. In this study, we identified the status of each site, determined key strategies being implemented, and designed based on the strategies implemented up to this point for solving problems associated with each sites through the use of causal loop diagrams. The results of the causal loop diagram analysis are as follows. The national archery center site was designed around strategies including planting green manure crops and introducing hugelkultur to reduce soil acidification and green network degradation. The hole site was designed as a constructed wetland based on the emergence of hygropreference vegetation, hydrated by rainwater collected at the bottom of hole, ecological and cultural benefits of such an environment. The arable land site restoration design was built around planting native vegetation on one part of the arable land site after soil quality improved and around restoration of grassland and a dry wetland on the other part of the site to reduce soil acidification, erosion, and green network degradation. This study is a significant attempt to apply principles of system dynamics to ecological restoration by providing the design strategies using comprehension of some problems in the ecosystem feedback loops, which has not been used before in general design processes for ecological restoration.

• The Journal of Korean Society for Radiation Therapy
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• v.17 no.2
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• pp.141-145
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• 2005

Purpose : It is known that the neutron is generally generated from the photon, its energy is larger than 10 MV. The neutron is leaked in the container inspection system installed at the customs though its energy is below 9 MV. It is needed that the spacial effect of the neutrons released from radiation treatment machine, linac, installed in the medical canter. Materials and Methods : The medical linear accelerator(Clinac 1800, varian, USA) was used in the experiment. Measuring neutron was used bubble detector(Bubble detector, BDPND type, BTI, Canada) which was created bubble by neutron. The bubble detector is located on the medical linear accelerator outskirt in three different distance, 30, 50, 120 cm and upper, lower four point from the iso-center. In addition, for effect on protect material we have measured eight points which are 50 cm distance from iso-center. The SAD(source-axis-distance), distance from photon source to iso-center, is adjusted to 100 cm and the field size is adjusted to $15{\times}15cm^2$. Irradiate 20 MU and calculate the dose rate in mrem/MU by measuring the number of bubble. Results : The neutron is more detected at 5 position in 30, 50 cm, 7 position in 120 cm and with wedge, and 2 position without mount. Conclusion : Though detection position is laid in the same distance in neutron measurement, the different value is shown in measuring results. Also, neutron dose is affected by the additional structure, the different value is obtained in each measurement positions. So, it is needed to measure and evaluate the neutron dose in the whole space considering the effect of the distance, angular distribution and additional structure.

• Korean Journal of Environment and Ecology
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• v.34 no.4
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• pp.274-281
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• 2020

This study aimed to investigate the autumn spawning by bitterling (A. rhombeus) inside mussel (Unio douglasiae) and the adaptation characteristics at the Bongseocheon Stream of Mankyeonggang River. The survey was carried out between August 2015 and July 2016. The spawning season was from September to November, and 17-75 (36.2 ± 16.44) eggs were found from mature females. During the survey period, 476 mussels were collected, 129 (27.1%) of spawned A. rhombeus. Mussels that spawned eggs, embryos, and larva of A. rhombeus (46.3 ± 4.55 mm, n = 129) were larger than than those that did not spawn (42.6 ± 8.51 mm, n = 347). The appearance frequency of A. rhombeus larva before and after the formation of lens was 99.8% (n = 597) vs. 0.2% (n = 1) from October 2015 to March 2016, 25.6% (n = 23) vs. 74.4% (n = 67) in April 2016, 0% (n = 0) vs. 100% (n = 40) on May 2016. The number of eggs, embryos, and larvae of A. rhombeus inside the mussels were 1-18 (5.6 ± 3.81). The number and appearance frequency of A. rhombeus eggs, embryos, and larvae inside the mussel according to mussel gill demibranchs position were 1 (0.01 ± 0.09, n = 1) and 0.78% in the left outer demibranch, 1-18 (2.33 ± 3.31, n = 63) and 48.84% in the left inner demibranch, 1-15 (2.97 ± 3.79, n = 76) and 58.91% in the right inner demibransh, and 1-12 (0.33 ± 1.71, n = 7) and 5.43% in the right outer demibransh. The highest frequency of the developmental position of eggs, embryos, and larvae occurred 71.8% (n = 445) in lower part 3 (L3) before formation lens and 94.4% (n = 102) in L3 after formation lens, indicating that L3 was dominating position for eggs, embryos, and larvae. More eggs, embryos, and larvae of A. rhombeus were found more often in the inner demibranshs than outer demibranchs. Since A. rhombeus is a species that spawn in the autumn and thus avoids the competition with interspecific and glochidia. However, they have to spend the winter in low water temperature. Consequently, we assume that A. rhombeus have evolved toward embryonic diapause under the low water temperature before the formation of lens and spawning inside the supracranchial cavity to save the transit energy from the water space to the suprabranchial cavity after the achieving movement ability with the formation of lens.

• Korean Journal of Poultry Science
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• v.33 no.1
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• pp.57-63
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• 2006

This study was conducted to investigate the effect of ventilating system of environmental controlled broiler house on broiler production. Three hundred eighty four broiler chicks (Hubbard, mean live weight of $44.5{\pm}2.0g/bird$) were reared for 2 wk. The results of the present study were summarized as follows : 1. Ammonia gas production was lower in the second and the third floors of cages compared with first floor of cages 13.5 and 13.5 vs 14.6 ppm, respectively). The observations of ammonia production in the morning and afternoon were similar. The production of carbon dioxide was not different between morning and afternoon, but it was tended to decrease in the forth floor of cages due to a fresh air 2. A wind velocity in the enclosed house was similar across lower, middle and upper section (0.57m/sec, 0.22m/sec and 0.04msec, respectively). In order to maintain an optimal air flow velocity in the cages, the duct entrance was punched, and then the air flow was full-round in the overall space in the cage. 3. Daily liveweight gain, feed intakes, and feed efficiency were not significant differences among treatments during whole experimental period (P>0.05). Therefore, the present results showed that temperature, moisture and atmosphere controlling were desirable, and air flew evenly in the cage.

• Korean Journal of Poultry Science
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• v.21 no.1
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• pp.1-19
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• 1994

This study was carried out to investigate the effects of shperical surface of eggs tray and eggshell on breaking strength of eggs for the development of a new egg tray design to prevent eggshell breakage. The results obtained were as follows: 1. According to the results obtained from investigation on the types of 22 egg trays collected from 9 countries(USA, Italy, France, Thailand, Japan, Netherland, Russia, Korea and Swiss), all egg trays except those from Korea were different in their types. 2. According to the determination of breaking strength for 4 pilot egg trays, type B and D were high in breaking strength. Trays B and D which would fit with the spherical surface of egg so that they could increase breaking strength were most recommendable. Breaking strength was not increased even though egg tray was strong. Thickness of eggshell of experimental eggs used in this experiment have no significance (P>0.05). 3. When eggs are packed and transported in egg tray, the breaking strength will depend on how much spherical surface of egg are covered by the spherical surface of the egg tray. Therefore, the inner spherical surface of egg tray must fit to the outer spherical surface of eggs when the egg tray is manufactured. 4. At present, there is only one type of egg tray being used in Korea despite the various egg sizes. In order to minimize the eggshell breakage, however, proper sizes or types of egg trays should be developed for each different categories of the egg size.

• Journal of Wetlands Research
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• v.19 no.2
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• pp.230-239
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• 2017

These days, the demand of farm tours is on the rise in Korea. However, most of them are related to farming experience. To overcome the situation, ecological experience is introduced. In this sense, it is necessary to obtain the contents and educational materials of ponds, the space of farming and ecological experience. Therefore, this study analyzed the use patterns of oriental medicine of pond wetland plants. Oriental medicine is used for old and traditional knowledge, and is still applied to various fields, such as medical science, pharmacy, and science. The analyzed result of this study will be helpful for the educational materials of ecological experience. This study surveyed plants of 40 pond wetlands in rural areas, and looked into the use patterns of traditional medicine by using the contents of Korea Traditional Knowledge Portal being operated by Korean Intellectual Property Office. According to the vegetation survey of the 40 pond wetlands, there were a total of 457 taxa in 108 families, 309 genera, 392 species, 59 varieties, 5 forma, and 1 subspecies. Among them, 314 taxa in 53 families, 136 genera, 265 species, 45 varieties, 3 forma, and 1 subspecies had the information on the use patterns of traditional medicine. It means that 68.8% of the plants around pond wetlands contain traditional medicine. Given other application patterns, such as food, handcraft and traditional farming, more than 70~80% are expected to include traditional knowledge. 314 taxa used for traditional medicine had 570 kinds of efficacy and 325 kinds of disease treatment. It means that one taxon has 4.0 (0~20) kinds of efficacy on average and 6.6(0~20) kinds of disease treatment. It is expected that this study result will be applied to various fields, including experience, education, and medical science. And it is considered that valuable pond wetlands are worthwhile to be conserved constantly.

• Journal of the Korean Society of Radiology
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• v.6 no.6
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• pp.455-464
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• 2012

This study suggested evaluation of approximately exposure to low-dose ionization radiation from medical images using a computed radiography (CR) system in standard X-ray examination and experimental model can compare diagnostic reference level (DRL) will suggest on optimization condition of guard about medical radiation of low dose space. Entrance surface dose (ESD) cross-measuring by standard dosimeter and optically stimulated luminescence dosimeters (OSLDs) in experiment condition about tube voltage and current of X-ray generator. Also, Hounsfield unit (HU) scale measured about each experiment condition in CR system and after character relationship table and graph tabulate about ESD and HU scale, approximately radiation dose about head, neck, thoracic, abdomen, and pelvis draw a measurement. In result measuring head, neck, thoracic, abdomen, and pelvis, average of ESD is 2.10, 2.01, 1.13, 2.97, and 1.95 mGy, respectively. HU scale is $3,276{\pm}3.72$, $3,217{\pm}2.93$, $2,768{\pm}3.13$, $3,782{\pm}5.19$, and $2,318{\pm}4.64$, respectively, in CR image. At this moment, using characteristic relationship table and graph, ESD measured approximately 2.16, 2.06, 1.19, 3.05, and 2.07 mGy, respectively. Average error of measuring value and ESD measured approximately smaller than 3%, this have credibility cover all the bases radiology area of measurement 5%. In its final analysis, this study suggest new experimental model approximately can assess radiation dose of patient in standard X-ray examination and can apply to CR examination, digital radiography and even film-cassette system.