• Journal of Navigation and Port Research
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• v.44 no.4
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• pp.305-311
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• 2020

Rising sea levels along the coast from global warming causes the increase of wave energy along the coast. This rise in sea levels results in relatively deep water levels, which would incur the loss of sand that had not occurred in the past from erosion in coastal areas. Generally, it has been challenging to protect against coastal erosion, and the slope, cross-sectional shape, and materials are selected for the site conditions depending on the change in external forces. However, the application of counter measures based on insufficient understanding of the phenomenon is causing various damage, indicating the need for technological development and converging technologies to improve credibility. In this study, we developed eco-friendly permeable biopolymer concrete blocks to control the coastal erosion by using the Bio-Coast, an effective porous structure that mitigates the destructive erosion caused by the rising sea levels. The hexagonal design of Bio-Coast was derived from the honeycomb, columnar joints, and clover, which are durable and stable structures in nature, and the design was changed to apply bumps on the Bio-Coast filling in the form of a clover to reduce wave overtopping and run-up. Applying the field condition of beaches on the east coast of Korea, the block weight and size were decided and the prototype blocks were manufactured and are ready for field placement. In particular, it is intended to protect coastal areas from destructive erosion by natural and artificial external forces, and to extend the design to river,s lakes, and natural walking trails, to improve the efficiency of quality control and process control through the use of blocks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8A
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• pp.745-751
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• 2006

The transmitter requires knowledge of the channel status information in order to adopt the adaptive modulation and coding scheme(AMC) for OFDM system. But in the outdoor environment which the users have high mobility, the channel status information from the users is outdated, so that it induces the degradation of system throughput and packet error rate(PER) performance. To solve this problem, researches about applying channel prediction technique to the AMC scheme have been proceeded. Most channel prediction techniques assume that there is no channel variation in the predefined time duration, e.g., a slot. As a result, those techniques cannot compensate the degradation of PER performance resulting from the rapid variation of channel during the slot duration. This paper introduces a novel channel prediction technique for OFDM/FDD system to support adaptive modulation and coding scheme over rapidly time-varying multipath fading channel. The proposed channel prediction technique considers the time-varying nature of channel during the slot duration. Simulation results show that the AMC scheme of OFDM/FDD system utilizing the proposed channel prediction technique can guarantee the target PER of 1% without any loss of system throughput compared with the case supported by the conventional channel prediction under ITU-R Veh A 30km/h.

• Korean Journal of Ichthyology
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• v.20 no.3
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• pp.167-172
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• 2008

The Korean bitterling, Acheilognathus signifer (Osteichthyes Cyprinidae), is an endemic and endangered species in Korea. During developmental stages, a small number of oculocutaneous albinism (with colorless body and eyeballs) were observed in the species. In order to investigate histological differences between normal and albinic bitterling, the dorsal skin and choroid-retina of the eyes were taken. The skin and eyes of normal and albino bitterling were similar in structure except for the presence or density of pigment cells. In normal bitterling, the epidermal melanocytes and dermal melanophores were abundantly developed in both the skin and epidermis of the eyes. But in the albino, the dorsal skin had few melanins, and the pigment cells over the choroid-retina pigment epithelium and iris of the eye were very small.

• Korean journal of applied entomology
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• v.42 no.4
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• pp.367-381
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• 2003

Dispersal polymorphism in insects Is a kind of adaptive strategy of the life history together with the diapause, consisting of the “long-winged or alate forms” of migratory phase and the “short-winged or apterous forms” of stationary phase. Dispersal polymorphism is a polymorphism related with the flight capability, and has three categories ; the wing polymorphisms, flight muscle polymorphisms, and flight behavior variations. Phase variation is another type of dispersal polymorphism varying in morphology, physiology and wing forms in response to the density of the population. The dispersal migration is a very adaptive trait that enables a species to keep pace with the changing mosaic of its habitat, but requires some costs. In general, wing reduction has a positive effect on the reproductive potential such as earlier reproduction and larger fecundity The dispersal polymorphism is a kind of optimization in the evolutionary strategies of the life history in insects; a trade-off between the advantages and disadvantages of migration. Wing polymorphism is a phenotypically plastic trait. Wing form changes with the environmental conditions even though the species is the same. Various environmental factors have an effect on the dispersal polymorphisms. Density dependent dispersal polymorphism plays an important role In population dynamics, but it is not a simple function of the density; the individuals of a population may be different in response to the density resulting different outcomes in the population biology, and the detailed information on the genotypic variation of the individuals in the population is the fundamental importance in the prediction of the population performances in a given environment. In conclusion, the studies on the dispersal polymorphisms are a complicated field in relation with both physiology and ecology, and studies on the ecological and quantitative genetics have indeed contributed to understanding of its important nature. But the final factors of evolution; the mechanisms of natural selections, might be revealed through the studies on the population biology.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.3
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• pp.225-231
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• 2020

Recently, there has been an increasing demand for SAR satellite as it can be operated regardless of the weather condition. In general, main reflector of the SAR is formed of multiple deployable panels to increase performance in the constrained payload envelope. By nature, deployable structure lacks structural stiffness and it is vulnerable to external disturbances and excitation. In particular, SAR satellites may have high levels of vibration occurring at the antenna reflecting surface due to higher angular rate requirements. During image capturing it is important to keep high surface accuracy of the reflector for the quality of images. In this research, a performance degradation of deployable SAR antenna due to structural deformation is analyzed. Panels for main reflectors are assumed to be flexible structures and multi-body simulation environment is established. Then, deflection of the panel is calculated while the satellite performs maneuvers. In addition, antenna gain and beam pointing error are analyzed to determine how these deflections affect antenna performance and mission.

• Korean Journal of Ecology and Environment
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• v.34 no.3 s.95
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• pp.239-250
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• 2001

Fish fauna of 13 sites in a main channel and its tributaries of the Taehwa River and 9 Sites of other headwater streams in the Ulsan area (Mt. Gaji) were investigated from February 1999 to October 2000. All sites were the 1st to 5th order streams in the Ulsan area, and 10 sites (45.5%) were intermittent streams. A total of 2,695 flsh specimens were collected and classified into 14 families and 44 species. Cyprinidae accounted for 40.9% (18 species) of the total fish species collected and 68.4% (1,845 ind.) of the total abundance. Subdominant families were Cobitidae (6 species; 78 ind.), Gobiidae (5 species; 240 ind.), and Gasterosteidae (2 species: 128 ind.). Zacco temmincki (RA 23.0%, 14 sites) was the dominant species; subdominant species were Moroco oxycephalus (20.2%, 11 sites), Zacco platypus (8.0%, 10 sites), Mugil cephalus (5.2%, 3 sites). Among the total species, 8 species were endemic species to Korea. The dominant Korean endemic species was Squalidus chankaensis tsuchigae (53.6% of Korean endemic species) and subdominant species were Iksookimia longicorpa (20.5%), and S. japonicus coreanus (6.6%) . Due to the intermittent nature of streams in the Ulsan area, a conservation program of nsh fauna is strongly needed.

• Applied Chemistry for Engineering
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• v.28 no.6
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• pp.607-618
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• 2017

Harmful air pollutants are exhausted from the various industrial facilities including the coal-fired thermal power plants and these substances affects on the human health as well as the nature environment. In particular, nitrogen oxides ($NO_x$) and sulfur dioxide ($SO_2$) are known to be causative substances to form fine particles ($PM_{2.5}$), which are also deleterious to human health. The integrated system composed of selective catalytic reduction (SCR) and wet flue gas desulfurization (WFGD) have been widely applied in order to control $NO_x$ and $SO_2$ emissions, resulting in high investment and operational costs, maintenance problems, and technical limitations. Recently, new technologies for the simultaneous removal of $NO_x$ and $SO_2$ from the flue gas, such as absorption, advanced oxidation processes (AOPs), non-thermal plasma (NTP), and electron beam (EB), are investigated in order to replace current integrated systems. The proposed technologies are based on the oxidation of $NO_x$ and $SO_2$ to $HNO_3$ and $H_2SO_4$ by using strong aqueous oxidants or oxidative radicals, the absorption of $HNO_3$ and $H_2SO_4$ into water at the gas-liquid interface, and the neutralization with additive reagents. In this paper, we summarize the technical improvements of each simultaneous abatement processes and the future prospect of technologies for demonstrating large-scaled applications.

• Journal of the Korean Society for Library and Information Science
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• v.30 no.2
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• pp.3-50
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• 1996

At present, Korean universities and colleges are confronted with a strong challenge, within and without, demanding a drastic change or innovation of university education. Discussion on the propulsion of the School Program is now under way as one of the means to reform the university education With such a background in mind, we have considered what should be the desirable course of Library and Information Science in Korea. We have considered the characteristic features and roles of library and information professionals to cope with the now approaching information society and the changing conditons of educational environment We have collected the pros and cons among professors of tile School Program, and investigated the curricula of the three universities which are at present practicing the School Program. Of the 139 professors to whom we have sent the questionnaries, $92(66\%)$ responded, of which the pros were 42 and the cons were 45. The model plan for the School Program is 'departmental school program' $(44\%)$, which purports to adopt 'departmental school program', with the curricula and material resources being utilized in common, or to adopt joint-appointment system with the common utilization of teaching materials and the introduction of a limited dual major system. The argument against introduction the School Program was that because of the peculiar nature of the discipline itself, Library and Information Science can not be merged with any other discipline.

• Journal of Environmental Impact Assessment
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• v.21 no.6
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• pp.823-839
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• 2012

Environmental Specimen Banks (ESBs) are playing pivotal role in monitoring the effect of environmental pollution on the ecosystem based on the retrospective analysis of the representative samples collected regularly and stored in cryogenic condition. In Korea, National Environmental Specimen Bank (NESB) was established in 2009 and the standard operating procedures (SOPs) for sampling, and cryogenic milling and storage had been prepared during 2007-2010. Since then, the tentative SOPs for the seven kinds of specimens (shoots of Red Pine (Pinus densiflora) and Korean Pine (Pinus koraiensis), leaves of Mongolian Oak (Quercus mongolica) and Zelkova Tree (Zelkova serrata), eggs of Feral Pigeon (Columba livia var. domestica), muscles and organs of Common Carp (Cyprinus carpio), and Freshwater Bivalve (Unio (Nodularia) douglasiae)) have been put to test in the field and laboratory as well against the practicality and feasibility. The SOPs were improved by reflecting the findings from the research and the following discussion regarding the selection of specimen (Feral Pigeon suffering from a control management), sample size (a problem of decreasing number of sampling trees related to increasing sampling time) and period (a problem related to a bud growth), and sampling methods etc.. In addition, barcoding system for the management of the specimen information, and monitoring system of the cryogenic storage to regulate the optimum temperature and the liquid nitrogen level were also developed for the efficient and effective control of the samples. Lastly, the safety guide and emergency protocol were augmented to guarantee a safe work environment with the cryogenic facility. These improvements of the SOPs are expected to contribute to more stable operation of the NESB.

• Journal of Environmental Impact Assessment
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• v.29 no.2
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• pp.144-155
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• 2020

This research developed an approach to identify ecologically important areas at local scales and explained how the results of this approach could contribute to extend the protected areas in the Republic of Korea (ROK). While most developed countries have considered various biotic and abiotic factors, ecological processes, migration routes, habitat connectivity, ecosystem services, and etc. to determine the protected areas, ROK has considered a few factors focusing on biodiversity, landscape, and the habitats of endangered organisms. However, for sustainable management of our nature, we need comprehensive understanding of various ecosystem factors and interactions among them at local scales in designating protected areas. Forthis, we developed a conceptual model based on the ecological engineering approach and then explained how the results of this approach could contribute to extend the protected areas. In particular, we considered future land-use and climate change in determining the priority areas for novel protected areas. Our research suggested an effective methodology 1) to include various ecosystem factors and 2) to consider future environmental changes as well as current environmental conditions in finding the ecologically important areas and prioritizing these areas. However, our approach has limitations on the real-world applications due to the lack of fundamental information and data on our ecosystems. To improve the effectiveness of our approach in the real-world applications, we need various long-term ecological research results, environmental and ecological monitoring data, and both current and future spatial environmental data.