• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.2
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• pp.105-114
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• 2007

Two-dimensional imaging of $V_s$ profile becomes more important in Korea because of the large horizontal variation of soil stiffness. To obtain a shear-wave velocity profile in geotechnical practice, various seismic nondestructive investigation methods are being frequently used. In this study, harmonic wavelet analysis of wave (HWAW) method is applied to the determination of $V_s$ profile to overcome some of weaknesses in the existing surface wave methods. HWAW method which is based on time-frequency analysis using harmonic wavelet transform has been developed to determine phase and group velocities of waves. Field testing of this method is relatively simple and fast because one experimental setup which consists of one pair of receivers is needed to determine $V_s$ profile of site. The proposed method uses the signal portion of the maximum local signal/noise ratio to evaluate the phase velocity to minimize the effects of noise, and uses single array inversion which considers receiver locations. Field tests were performed in 2 sites in order to evaluate accuracy of test method and estimate the applicability of 2-D imaging by HWAW method. Through field applications and comparison with other test results, the good accuracy and applicability of the proposed method were verified.

• Archives of design research
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• v.20 no.1 s.69
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• pp.45-54
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• 2007

Recent research regarding local traditions, cultural heritage, and sightseeing resources that represent local characteristics for the purpose of local promotion has been actively advanced. Yangyeongsi in Daegu, South Korea is Doing developed as a core location in order to revitalize regional culture. The unique tradition and functions of this city area have been preserved. Previous research "The Fundamental Research of Revitalization for Yangyeongsi in Daegu for the Local Promotion" undertaken by the author revealed a lack of fundamental research available to establish an understanding of how to revitalize Yangyeongsi. The research methodology designed this by, (1)a site investigation and verification of previous research (2)a deep analysis of Yangyeongsi to uncover potential improvement opportunities (3) assessment of essential elements and appropriate directions for revitalization of the traditional market (4) application of the environment design improvement process to the local design center. The design proposal is that, firstly, space assessment will De improved by the maintenance and expansion of fundamental facilities. Secondly, space application can be maximized by servicing the complex road network through a traffic flow plan. In addition, consideration for the local characteristics will promote unity and identification with the region. Lastly, revitalization and industrialization development of sightseeing resources and secure streets and event spaces will promote enjoyable experiences for visitors. Research results were submitted to the local authority and applied to the future policy plan. Continuous research on revitalization and analysis of the local characteristics are recommended in order to benefit local promotion.

• The Journal of Engineering Geology
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• v.28 no.3
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• pp.379-395
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• 2018

A walking trail environment can be divided into the upper part of the trail, the trail itself, and the lower part of the trail. In this study, based on field investigations, we developed a risk index for trails by considering human/societal factors that affect each of these three trail environments. A checklist was developed for field investigations, and checklist items were scored through relative importance analysis. The relative weights of items were analyzed using the AHP (Analytic Hierarchy Process) technique, revealing that the upper environment of a trail is twice as important as the rest of the environment. The importance and score of items belonging to each environment were determined. We define the risk index as the sum of the item scores. Weights were added using data from existing investigations including landslides risk rating and designated risk steep slopes. The risk index has a maximum value of 200, and the maximum and minimum calculated scores of 335 risk sections were 159 and 64.2, respectively. As a result of comparative analysis between field observations and risk index calculations, most sections at relatively low risk had risk values less than 100, and sections with high risks or that had been the site of accident yielded scores that exceeded 140.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.6
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• pp.35-50
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• 2017

This study is to see the recovery effect of the Deltacon method by investigating the amount of sand deposition, the topographical cross section and the vegetation structure; and to derive the effective recovery method of coastal erosion area. The target areas of this study include Jinri coastal dune, Bajireum coastal dune and Seopori coastal dune in Deokjeok-do Island, Ongjin-gun, Incheon. In order to assess the current status of the coastal erosion area recovery, the soil profile structure map was prepared on the site and then the amount of sand deposition within 1m was calculated indoors. The vegetation recovery status of the costal erosion area was assessed via the analyses of the topographical profile structure and the plant community structure, and we aim to derive the effective recovery plan of the Deltacon method with the results. With the Deltacon method, structures with ductile material, special non-woven fabric bags filled with soil and vegetation can be performed therefore the structuralstability and prevention of sand erosion can be achieved. The amounts of sand deposition of Bajireum coastal dune, Seopori costal dune and Jinri costal dune were calculated $0.98{\sim}2.54m^3$, $1.02{\sim}2.96m^3$, and $0.27{\sim}0.75m^3$, respectively, and it is considered that the costal erosion recovery is actively performed for Bajireum costal dune and Seopori costal dune. The analysis results of vegetation structures by topography show that the installation of the send collecting net in steep areas has been highly effective and the Deltacon-constructed target areas have been restored to vegetation and the costal dune, which is similar to the natural dune. The investigation of the plant community structure in Deokjeok-do Island costal dune, Incheon displayed similar research results of the existing costal dune flora and confirmed the emergence of Lathyrus japonicus, Carex kobomugi, Elymus mollis, Vitex rotundifolia, and Calystegia soldanella and others. In order to carry out further effective recovery with the Deltacon method, improvements to rootage of herbaceous vegetation are needed in areas without foredune herbaceous vegetation, and continuos maintenance & management monitoring of connected windbreak forest to costal dunes are also necessary.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.1
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• pp.46-53
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• 2005

This paper describes the mean grain size and shear strength properties related to subsidence characteristics using sediment samples and acoustic images obtained from artificial reef areas in Tongyoung and Jangsungpo offshore. The acoustic images collected from chirp sonar and side scan sonar show well the attitude/orientation, the distribution pattern, and the degree of subsidence of artificial reefs, suggesting the possibility of suitable site investigation and the management of the reefs using acoustic sonar. The sediments were largely composed of clayey silt and silty clay. The mean grain sizes in Tongyoung and Jangsungpo offshore show the ranges of 5${\sim}$9${\Phi}$ and 8${\sim}$9${\Phi}$, respectively. The shear strength was significantly increased at the depths of 20cm in Tongyoung offshore and 80cm in Jangsungpo offshore, corresponding to the subsidence depth of artificial reefs. The relationship between mean grain size and shear strength did not show a correlation, suggesting the shear strength does not totally depend on mean grain size. Provided subsidence characteristics with respect to various artificial reefs and seabed condition are investigated in more details, the constructing area of the reef can be more extended.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.7
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• pp.387-394
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• 2016

Commercial 28 algae removal technologies that have been applied in domestic rivers and lakes with green tide were investigated, analyzed and classified. The classification of algae removal technologies was based on the three criteria (i.e., principle, flow rate of water body, and application period). Also, algae removal technologies were evaluated in terms of cost effectiveness, field applicability, effect durability, and eco friendliness. From the analysis results, technologies using physical, chemical, biological, and convergent controls were 32.2%, 25%, 21.4%, and 21.4%, respectively. The 75% of technologies have been applied to stagnant water body (${\leq}0.2m/s$). Also, algae harvesting ship with dissolved air flotation, conveyor belt and filtration processes and natural floating coagulant were found to have better field applicability, compared to other technologies. However, proper algae removal technology in specific rivers and lakes should be chosen after the evaluation of long-term pilot scale field test. Also, development of energy and resource recovery technologies from algae biomass is warranted.

• Journal of Pharmaceutical Investigation
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• v.31 no.3
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• pp.151-160
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• 2001

The purpose of this study is to investigate the interaction of progesterone with various cyclodextrins (CDs) in the aqueous solution and in solid state, and finally to formulate a parenteral aqueous formulation. CDs used were ${\alpha}-$, ${\beta}-$, and ${\gamma}-CD$, $2-hydroxypropyl-{\beta}-CD$ (HPCD), sulfobutyl $ether-{\beta}-CD$ (SBCD), $dimethyl-{\beta}-CD$ (DMCD) and $trimethyl-{\beta}-CD$ (TMCD). The solubility studies of progesterone were performed in the presence of various CDs as a function of concentration or temperature. The solubility of progesterone increased in the rank order of ${\alpha}-CD$ < ${\beta}-CD$ < ${\gamma}-CD$ < TMCD$ < HPCD < DMCD < SBCD. Addition of SBCD (200 mg/ml) in water increased the aqueous solubility $(9.36\;{\mu}g/ml)$ about 3,200 times, and lowering the temperature facilitated the solubilization of progesterone. However, the addition of HPCD and SBCD in 20:80 (v/v) polyethylene glycol 300-water and propylene glycol-water cosolvents markedly decreased the solubility of progesterone, compared with solubilizing effects in water. Physical mixtures and solid dispersions of progesterone with HPCD or SBCD were prepared, and evaluated by differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), near IR spectroscopy and dissolution studies. By DSC and IR studies, it was found that progesterone was dispersed in HPCD in monotectic state and dissolved rapidly from both solid dispersions. Based on solubility studies, new aqueous progesterone fonnulations (5 mg/ml) containing SBCD (200 mg/ml) could be prepared and did not form precipitates even after 2 months at $4^{\circ}C$. The solution was transparent when mixed with normal saline and 5% dextrose injection at 1: 1, 1:10 and 1:20 (v/v) even after 7 days. Permeation rates of progesterone through a cellulose membrane from 20% PEG 300 solution $(50\;{\mu}g/ml)$ containing HPCD or SBCD were compared with oily formulation. Permeation of progesterone from oily formulation did not occur up to 8 hr, but aqueous formulations showed fast permeation rates from early stage of permeation study. The addition of HPCD or SBCD retarded the permeation rates of progesterone with the increase of CD concentrations, suggesting the possibility of a controlled absorption from the site administered intramuscularly. These results demonstrate that it is feasible to develop a new progesterone parenteral aqueous injection (5 mg/ml) using SBCD.

• Analytical Science and Technology
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• v.31 no.5
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• pp.185-194
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• 2018

At the end of November 2010, livestock infected with foot and mouth disease (FMD) were buried, increasing concern about secondary pollution of drinking water and groundwater with odor. Hence, measures to reduce pollution of drinking water and groundwater are needed. In this study, based on livestock type and soil texture, five pilot-scale burial sites were monitored for the past three years from Feb 2012 to 2015. Leachate from the site was analyzed for 90 compounds. A detailed investigation has been completed, looking into organic matter decomposition characteristics of the buried bodies, relevant trace elements thereof, and in particular metabolite concentration changes such as the degree of decomposition of a carcass. From the results, no detectable heavy metals, including cadmium and arsenic, were measured. Among animal types, the rate of cattle decomposition is faster than swine decomposition, and the decomposition of the bodies were performed in sequence from sand, clay loam, sandy loam.

• Journal of the Mineralogical Society of Korea
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• v.20 no.3
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• pp.165-173
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• 2007

The KAERI Underground Research Tunnel (KURT) located in KAERI (Korea Atomic Energy Research Institute) was recently constructed following the site investigation in 2003. Its dimension is 180 m in length, 6 m in width, and 6 m in height, and it has a horseshoe-like cross-sec-lion and is located in the ground to the depth of 90 m. When the tunnel was dug into the ground with 100 m in length, fresh rocks, weathered rocks and fracture-filling materials were taken and examined by mineralogical and chemical analyses. There are phyllosilicate minerals such as illite, smectite and chlorite including calcite, which are filling some faults and cracks of the KURT rock. The illite and smectite usually coexist in the fracture, where their content ratio is different according to which mineral is predominant. There are high concentrations of U and Th in the rocks coated with iron-oxides and filled with secondary materials as compared with those in the fresh rocks. It seems that the radionuclides, which are slowly leached from the parent rocks or exist as a dissolved form in the groundwater and hydrothermal solution, may have been migrated along the fractures and thereafter selectively sorbed and coprecipitated on the iron-oxides and the fracture-filling materials. These results will be very useful far the evaluation of environmental factors affecting the nuclides migration and retardation when long-term safety is considered to the geological disposal of high-level radioactive wastes in the future.

• Journal of Periodontal and Implant Science
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• v.49 no.6
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• pp.355-365
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• 2019

Purpose: The modified minimally invasive surgical technique (M-MIST) has been successfully employed to achieve periodontal regeneration. Platelet-rich fibrin (PRF) is known to enhance wound healing through the release of growth factors. This study aimed to observe the outcomes of periodontal surgery when M-MIST was used with or without PRF for the treatment of isolated intrabony defects. Methods: This randomized clinical trial was conducted on 36 systemically healthy patients, who had chronic periodontitis associated with a single-site buccal probing pocket depth (PPD) and clinical attachment level of ≥5 mm. Patients were randomly divided into 2 groups: the test group treated with M-MIST and PRF, and the control group treated with M-MIST alone. The primary periodontal parameters analyzed were PPD, relative attachment level (RAL), and relative gingival margin level. The radiographic parameters analyzed were change in alveolar crest position (C-ACP), linear bone growth (LBG), and percentage bone fill (%BF). Patients were followed up to 6 months post-surgery. Results: Intragroup comparisons at 3 and 6 months showed consistently significant improvements in PPD and RAL in both the groups. In intergroup comparisons, the improvement in PPD reduction, gain in RAL, and the level of the gingival margin was similar in both groups at 3 and 6 months of follow-up. Furthermore, an intergroup comparison of radiographic parameters also demonstrated similar improvements in C-ACP, LBG, and %BF at 6 months of follow-up. Conclusions: M-MIST with or without PRF yielded comparable periodontal tissue healing in terms of improvements in periodontal and radiographic parameters. Further investigation is required to confirm the beneficial effects of PRF with M-MIST.