• Korean Journal of Ecology and Environment
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• v.56 no.2
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• pp.140-150
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• 2023

The Hangang River^* is necessary to manage the water environment of severe pollution due to the high density of residential areas, parks, and agriculture and the large population concentrated there. Benthic macroinvertebrates, such as chironomids larvae, are bioindicator species that reflect environmental changes and are crucial for water quality monitoring. In this study, we investigated morphological characteristics and molecular analysis of the chironomids larvae inhabiting the Hangang River area for water environment surveys. For this research, 20 rivers, lakes, and urban area in the Hangang River basin were selected. Chironomids larvae were collected from July to September 2022, and their appearance and characteristics were identified through morphological identification. In addition, phylogenetic analysis was performed based on the mtCOI gene sequences of the collected chironomids larvae, and identification at the genus level was confirmed. As a result, 32 species and 18 genera of 3 subfamilies of Chironomidae larvae were identified, and Stictochironomus sp. dominated most sites(6 sites). The morphological characteristics of the identified chironomids larvae, such as the mentum, ventromental plate, and antenna, were organized into table and pictorial keys, and a Bayesian inference molecular phylogeny was presented. These results provide basic morphological information for genus-level identification and can be used as fundamental information for water quality management.

• Journal of Navigation and Port Research
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• v.47 no.3
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• pp.128-133
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• 2023

In order for Aids to Navigation to provide sustainable services to users, it is possible when there is no Aids to Navigation accident. If an Aids to Navigation accident occurs, the manager should efficiently manage it to prevent the same accident. However, the current Aids to Navigation accident management only specifies the cause and type of the accident. There are no separate guidelines. Thus, the accident is recorded differently depending on the manager. Therefore, this study attempted to redefine Aids to Navigation accident. To this end, Aids to Navigation accidents that have occurred over the past 23 years (year 2000 to years 2022), IALA's Aids to Navigation information standard, S-201, and categories of accidents (traffic accidents and marine accidents) were analyzed. Causes of Aids to Navigation accidents were divided into internal and external causes. Accidents were divided into three types: Light tower accident, buoy accident, and equipment accident. By further subdividing primary items, the cause of accident was reestablished into 7 items such as mooring and bad weather and 11 items such as Light tower damage, buoy loss, and equipment breakdown. These research results can be used as basic data to provide future Aids to Navigation accident statistics.

• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.451-458
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• 2023

As forest fires continue to increase in scale worldwide, the importance of forest roads in relation to forest fire prevention and suppression has become increasingly evident. To ensure effective functioning during a forest fire disaster, it is crucial to apply appropriate road planning and ensure roads' structural integrity. However, previous studies have predominantly focused on the impact of forest fires on firebreak efficacy and road placement, meaning that insufficient attention has been paid to ensuring the safety of these facilities. Therefore, this study sought to compare the strength of concrete facilities within areas damaged by forest fires over the past three years by using the rebound hammer test to identify signs of thermal degradation. The results revealed that concrete facilities damaged by forest fires exhibited significantly lower strength (15.6 MPa) when compared with undamaged facilities (18.0 MPa) (p<0.001), and this trend was consistent across all the target facilities. Consequently, it is recommended that safety assessment criteria for concrete forest road facilities be established to prevent secondary disasters following forest fire damage. Moreover, continuous monitoring and research involving indoor experiments are imperative in terms of enhancing the stability of forest road structures. It is expected that such research will lead to the development of more effective strategies for forest fire prevention and suppression.

• Journal of Aquaculture
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• v.3 no.1
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• pp.49-63
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• 1990

A population ecological study was carried out to estimate survival and growth rates, biomass, biological production and turnover ratio of cultured sea squirt, Halocynthia roretzi, by growth stages, using data from in situ culture experiment off Hansando in the southern part of Korea from February 1985 to July 1986. The squirt population followed an exponential decay function and the instantaneous coefficient of total mortality (Z) was estimated to be 0.0614 $month^{-1}$(Var (Z) = 0.000126). Growths in total weight and meat weight of squirts were expressed as linear functions during the period of culture experiment. The growth of squirts showed a negative correlation with the water temperature. The mean biomass per string ranged from 2.14 kg for March of the first year to 16.26 kg for March of the next year. The biological production per string was estimated to range from 3.28 kg for the first summer (June - July) to 6.46kg for the first late winter (February-March). The peak of turnover ratio occurred in the late winter (February-March) as 3.013 and the ratios sharply declined thereafter. Based on the results of this study, management implications for culturing sea squirts were also suggested. The optimum harvest time ($t_{mb}$) when the peak biomass in terms of total weight occurred was estimated to be late June of the second year, which corresponded to 16.7 months after the main hanging. However, the time when the peak biomass in terms of meat weight was occurred was early July of the second year. The maximum harvest biomass was 17.4 kg per string in terms of total weight and 6.3 kg per string in terms of meat weight. In conclusion, the process of culture should be conducted on the basis of the knowledge of population ecological theories as shown in this study.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.2
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• pp.275-281
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• 2018

It is known that he pollutant emitted from the combustion process of marine fuel oil causes air pollution and harmful effects to the human body. Accordingly, IMO regulates pollutants emitted from ships. However, the regulation of Particulate Matter (PM) is still in the process of debate, so preemptive action is needed. Fundamental research on PM is essential. In this study, the Dimensionless Light Extinction Constant ($K_e$) of fuel oil used in marine diesel engines was measured and analyzed to construct the basic data of the PM generated from marine-based fuel oil. The fuel oil used in the land diesel engine was measured in the same way for character comparison. Both fuel oils differ in sulfur content and density. The $K_e$ was measured via the optical method using a 633 nm laser and was determined by using the volume fraction of PM collected by the gravimetric filter method. The $K_e$ of the PM discharged from marine fuel oil is 8.28, and the land fuel oil is 8.44. The $K_e$ of two fuel oils was similar within the measurement uncertainty range. However, it was found by comparison with the value obtained by the Rayleigh-Limit solution that the light scattering portion could be large. Also, it was found that light extinction characteristics could be different due to the relationship between light transmittance and collected mass.

• Journal of Aquaculture
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• v.18 no.2
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• pp.122-129
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• 2005

Ammonia is the major limiting factor in intensive aquaculture production systems. Therefore, quantification of ammonia excretion is important for the water quality management in aquaculture systems. Ammonia excretion is known to be affected by many factors such as body weight and dietary protein level (DPL). In this study, experiments were carried out to investigate the effects of body weight and DPLs on the rates of ammonia excretion of Nile tilapia Oreochromis niloticus. Three sizes of fishes (mean initial weight; 4.8 g,42.7 g and 176.8 g) were fed each of two dietary protein levels (30.5% and 35.5%). Daily feeding levels for the three fish sizes of 4.8 g, 42.7 g and 176.8 g were 6%, 3%, and 1.5% body weight per day, respectively. Each group of fish was stocked in a 17.1-L aquarium and all treatments were triplicated. Following feeding, the weight-specific ammonia excretion rate of O. niloticus increased, peaked at 4 to 8 h, and returned to pre-feeding levels within 24 h. Total ammonia nitrogen (TAN) excretion.ate per unit weight decreased with the increase of fish weight for each diet (P<0.05). The TAN excretion rate increased with increasing dietary protein content for each fish size (P<0.05). TAN excretion rates (Y) for each diet with different fish weights were described by the following equations: low DPL diet (30.5%): $Y\;(mg\;kg^{-1}\;d^{-1})=955.69-147.12\;lnX\;(r^2=0.95)$, high DPL diet (35.5%): $Y\;(mg\;kg^{-1}\;d^{-1})=1362.41-209.79\;lnX\;(r^2=0.99)$. Where: X=body weight (g wet wt.). The TAN excretion rates ranged 28.5%-37.1% of the total nitrogen ingested for the low DPL diet (30.5%) and 37.4-38.5% for the high DPL diet (35.5%). Total nitrogen losses of fish fed the high DPL diet $(35.5%;\;0.26\sim0.91g\;kg^{-1}\;d^{-1})$ were higher than those fed the low DPL diet $(30.5%;\;0.22\sim0.68g\;kg^{-1}\;d^{-1})$. The losses decreased per kg of fish as fish size increased. Results will provide valuable information fer water quality management and culture of Nile tilapia in recirculating aquaculture systems.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.630-647
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• 2021

We determined the current problem of the restoration deposit-estimation system, stipulated by the Mountainous Districts Management Act, using the Delphi technique. Consequently, we proposed a standard model for forest land restoration to derive a reasonable deposit-estimation system. With the result of the Delphi survey, the inappropriateness of land-use type and slope gradient classifications was shown; the insufficiency of standard works was a significant problem in the current system. A way to solve these problems was devised, to reorganize the current land-use type into the subject of the site. The specific subjects included the following: (i) to permit or report forest land-use change and temporary use of forest land, (ii) to report temporary use of forest land, (iii) to permit stone collection or sale for mineral mining, and (iv) to allow sediment collection. The current slope gradient subdivision into (a) θ<10°, (b) 10°≦θ<15°, (c) 15°≦θ<20°, (d) 20°≦θ<25°, (e) 25°≦θ<30°, and (f) θ≧30° and the reorganization of 17 standard works into 22 standard works were deemed as solutions, along with seven additional works. We developed 24 standard models for the forest land restoration project based on the aforementioned results. The deposits estimated by these models ranged from 34,185,000 (Korean) won to 607,403,000 won. If additional works, premiums, discounts, and supervision fees are added to the models, the deposit increases to an estimated 668,143,000 won subject to permission for stone collection or sale and mineral mining. Experts agree on the distribution of the restoration deposits estimated by these models at a high level in the Delphi survey. Our findings are expected to contribute to securing the appropriateness of the restoration cost deposited for the smooth performance of the vicariously executed restoration project.

• Journal of Marine Life Science
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• v.1 no.2
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• pp.95-108
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• 2016

This study was performed to investigate the community structure of macrobenthic assemblages in the Environmental Conservation area, Korea. Benthic animals were collected by van Veen grab sampler at spring (May) and summer (August) 2009. The total species number and mean density were 195 species 5.6 m^-2 and 667 individuals m^-2, respectively. Polychaetes were the most dominant faunal group in species (96 species) and abundance (431 individuals m^-2). The major dominant species were the polychaetes Lumbrineris longifolia (76±224 individuals m^-2), Mediomastus californiensis (42±117 individuals m^-2), Tharyx sp.3 (26±110 individuals m^-2), the bivalvia Theora fragilis (54±78 individuals m^-2) and the amphipod Eriopisella schellensis (70±146 individuals m^-2). Based on the cluster and nMDS ordination analysis, macrobenthic communities were divided into three faunal groups. The first group was characterized by high abundance of the polychaeta Sternaspis scutata and the amphipod Ampelisca cyclops iyoensis, which is located by most stations of Hampyeong Bay and St. 4 of Deungnyang Bay. The second group was numerically dominated by the polychaeta Capitella capitata at St. 4 and St. 5 in Gamak Bay where was most pollutant area. Finally, the third group was dominated by the polychaetes Heteromastus filiformis, Tharyx sp.3 and the amphipod Sinocorophium sinensis. Therefore, geochemical characteristics such as the bay shape and pollution gradient may be important factors controlling of the macrobenthic community structure in Environment Conservation Area.

• Journal of the Korean Society for information Management
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• v.39 no.4
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• pp.191-213
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• 2022

With a view to providing a high-quality policy information service beyond the existing national task service of the national policy information portal (POINT) of the National Library of Korea Sejong, it would be necessary to effectively provide the policy data needed for the implementation of the new national tasks. Accordingly, in this study, an attempt has been made to find a way to connect and develop the BRM-based national tasks and the policy information contents. Towards this end, first, the types of national tasks and the contents of each field and area of the government function's classification system were analyzed, with a focus placed on the 120 national tasks of the new administration. Furthermore, by comparing and analyzing the national tasks of the previous administration and the current information, the contents ought to be reflected for the development of contents related to the national tasks identified. Second, the method for linking and collecting the policy information was sought based on the analysis of the current status of policy information and the national information portal. As a result of the study, first, examining the 1st stage BRM of the national tasks, it turned out that there were 21 tasks for social welfare, 14 for unification and diplomacy, 17 for small and medium-sized businesses in industry and trade, 12 for general public administration, 8 for the economy, taxation and finance, 6 for culture, sports and tourism, science and technology, and education each, 5 for communication, public order and safety each, 4 for health, transportation and logistics, and environment each, 3 for agriculture and forestry, 2 for national defense and regional development each, and 1 for maritime and fisheries each, among others. As for the new administration, it is apparent that science technology and IT are important, and hence, it is necessary to consider such when developing the information services for the core national tasks. Second, to link the database with external organizations, it would be necessary to form a linked operation council, link and collect the information on the national tasks, and link and provide the national task-related information for the POINTs.

• Journal of Navigation and Port Research
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• v.47 no.3
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• pp.147-154
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• 2023

This study aims to determine the necessity, role, utilization, and operation and management plan in relation to the underwater space platform where humans can newly reside. It provides a comprehensive opinion on the need for creating undersea space and operation plans based on opinions of industry-university-affiliated organizations involved in the R&D project of the Ministry of Maritime Affairs and Fisheries for the utilization of undersea space and external experts participating in marine technology development. In this study, a survey was conducted on researchers participating in the construction of a Korean submarine space platform. FGI was conducted on marine technology development experts. Results were then derived. As a result of the analysis, the need for subsea space construction was found to be high. As for the role of subsea space, the most common opinion was to develop technology for utilizing subsea space and to secure marine science research functions. It was found that the creation of subsea space would have a positive impact on the domestic industry, especially the deep-sea development industry and the shipbuilding/offshore structure industry. In terms of utilization, after the end of the seabed space test bed, the response to utilization as a marine observation base and marine ecosystem research had the highest proportion. As for expected inconvenience, discomfort in the psychological environment was the highest. Experts suggest that securing a continuous budget is most important for stable operation in the future and that securing a manpower budget is essential for itemized budgets. In addition, it was judged that it would be appropriate to establish a prior agreement from the time of the prior agreement and prepare a countermeasure before proceeding with the project in order to ensure ownership issues, consignment management issues, and cost issues when using the project after the end of the project.