• Journal of Korea Multimedia Society
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• v.11 no.4
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• pp.423-433
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• 2008

The surface curvatures extracted from the face contain the most important personal facial information. In particular, the face shape using the depth information represents personal features in detail. In this paper, we develop a method for recognizing the range face images by combining the multiple face regions using fuzzy integral. For the proposed approach, the first step tries to find the nose tip that has a protrusion shape on the face from the extracted face area and has to take into consideration of the orientated frontal posture to normalize. Multiple areas are extracted by the depth threshold values from reference point, nose tip. And then, we calculate the curvature features: principal curvature, gaussian curvature, and mean curvature for each region. The second step of approach concerns the application of eigenface and Linear Discriminant Analysis(LDA) method to reduce the dimension and classify. In the last step, the aggregation of the individual classifiers using the fuzzy integral is explained for each region. In the experimental results, using the depth threshold value 40 (DT40) show the highest recognition rate among the regions, and the maximum curvature achieves 98% recognition rate, incase of fuzzy integral.

• Journal of Adhesion and Interface
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• v.22 no.3
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• pp.91-97
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• 2021

By introducing an organic interlayer on the Parylene C dielectric surface, the electrical device performances and the operating stabilities of organic field-effect transistors (OFETs) were improved. To achieve this goal, hexamethyldisilazane (HMDS) and octadecyltrichlorosilane (ODTS), as the organic interlayer materials, were used to control the surface energy of the Parylene C dielectrics. For the bare case used with the pristine Parylene C dielectrics, the field-effect mobility (μ_FET) and threshold voltage (V_th) of dinaphtho[2,3-b:2',3'-f ]thieno[3,2-b]- thiophene (DNTT) FET devices were measured at 0.12 cm²V^-1s^-1 and - 5.23 V, respectively. On the other hand, the OFET devices with HMDS- and ODTS-modified cases showed the improved μ_FET values of 0.32 and 0.34 cm²V^-1s^-1, respectively. More important point is that the μ_FET and V_th of the DNTT FET device with the ODTS-modified Parylene C dielectric presented the smallest changes during a repeated measurement of 1000 times, implying that it has the most stable operating stability. The results could be meaned that the organic interlayer, especially ODTS, effectively covers the Parylene C dielectric surface with alkyl chains and reduces the charge trapping at the interface region between active layer and dielectric, thereby improving the electrical operating stability.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.4
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• pp.335-341
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• 2020

This study investigates the association of the AFB stain with the cycle threshold (Ct) value of the Cobas TaqMan MTB test (CTM test, Roche Diagnostics, Basel, Switzerland), and it establishes the base data for semi-quantitative identification of M. tuberculosis by the Ct value. CTM test were simultaneously conducted on 8,389 specimens submitted to the Samsung Medical Center from January 2015 to December 2015, and the results were analyzed and compared retrospectively investigates the association of the AFB stain with the Ct value of the CTM test, and it establishes the base data for semi-quantitative identification of M. tuberculosis by the Ct value. The Ct values for 135 positive specimens of the CTM were inversely correlated with the AFB stain (rs=-0.545, P<0.01). When the Ct value of the CTM test and the time to positivity (TTP) of the mycobacteria cultures were verified based on the AFB stain, they were found to have a positive correlation (rs=0.136, P<0.01). The negative correlation between the CTM test and the AFB stain grade was demonstrated. The clinical significance was verified by applying these criteria to the clinical results. The semi-quantitative criteria of this study can be used to facilitate the rapid isolation of patients with active tuberculosis and infection control in the hospital.

• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.4
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• pp.199-208
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• 2021

Purpose: The purpose of this study was to compare and evaluate the masking ability of three types of high translucent zirconia according to the various thicknesses and backgrounds. Materials and Methods: Using three types of high-translucency zirconia (Ceramill zolid fx white, Ceramill zolid ht+ white, Ceramill zolid ht+ preshade A2), 10 cylindrical specimens were fabricated in 10mm diameter and each with four thicknesses (0.6 mm, 1.0 mm, 1.5 mm, 2.0 mm), respectively by CAD/CAM method. The background was 10 mm in diameter and 10 mm in thickness. A1, A2, A3 flowable resin backgrounds, blue-colored core resin background, and Ni-Cr alloy background were prepared, and black, white backgrounds provided by the spectrophotometer manufacturer (x-rite, Koblach, Austria) were used. zirconia specimens and the background specimen were stacked to measure L, a^*, b^* with Spectrophotometer (Color i5, x-rite, Koblach, Austria) and the ΔE value with the other background is calculated. The Calculated mean ΔE values were compared based on perceptibility threshold 1.0 and acceptability threshold 3.7. Nonparametric tests such as Kruskal-Wallis test were performed to verify statistical significance (α = 0.05). Results: There was a significant difference in the mean ΔE value according to the zirconia type, background and thickness change (P = 0.000). Conclusion: According to the results of this study, the pre-colored high-translucent zirconia can obtain the desired zirconia shade when it is restored on teeth, composite resins, and abutments except for the blue resin core.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.1
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• pp.35-47
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• 2022

Expansion of potato production areas can improve the food security in North Korea because the given crop has less requirements for agricultural materials and facilities. The Global Agro-Ecological Zones (GAEZ) model, which was developed to evaluate climate suitability under different cultivation conditions, was used to identify potential areas for the potato production. The spatial estimates of crop suitability under low and high input management conditions were downloaded from the GAEZ data portal. The values of suitability were obtained at the potato occurrence sites retrieved from the Global Biodiversity Information Facility (GBIF) database. The suitable areas for the potato production were identified using a threshold value derived from the suitability estimates at the occurrence sites. It was found that 90% of the occurrence sites had the suitability index value >3,333, which was set to be the threshold value. The suitable areas in North Korea were summarized by province and county. Rice cultivation areas were excluded from the analysis. The reported relative acreage of potato production was better represented by the suitable areas under the low input management options than the high input conditions. The suitable areas also had a similar distribution to the reported acreage of potato production by county. These results indicated that the GAEZ model would be useful to identify the candidate production areas, which would facilitate the increases in potato production especially under future climate conditions. Furthermore, monthly maps of crop suitability can be used to design cropping systems that would improve crop production under the limited use of agricultural materials and facilities.

• Korean Journal of Audiology
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• v.24 no.1
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• pp.29-34
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• 2020

Background and Objectives: Bilateral microphones with contralateral routing of signal (BiCROS) hearing aid is an option for hearing rehabilitation in individuals with asymmetric sensorineural hearing loss (ASNHL). The clinical factors influencing the trial and purchase of BiCROS were investigated. Subjects and Methods: We reviewed the medical records of 78 patients with ASNHL who were recommended to use BiCROS and analyzed the demographic and audiological factors influencing the trial and purchase of BiCROS. Results: Among the 78 patients, 52 (66.7%) availed of the free BiCROS trial and 21 (26.9%) purchased BiCROS. The mean pure tone audiometry (PTA) air conduction (AC) threshold of the better- and worse-hearing ears were 44.2±12.8 dB and 90.7±22.5 dB HL, respectively. The decision for trial or purchase of BiCROS was not influenced by age, sex, duration of hearing loss of the worse-hearing ear, or PTA AC threshold or speech discrimination score of both ears. The first and third quartiles of the PTA AC thresholds for the better-hearing ear of BiCROS buyers were 38.75 dB and 53.75 dB HL, respectively. The counterpart values for the worse-hearing ear were 72.50 dB and 118.75 dB HL, respectively. Conclusions: The clinical factors analyzed in this study were found to be irrelevant to the trial and purchase of BiCROS in patients with ASNHL. Nevertheless, the distribution range of the auditory thresholds of the subjects using BiCROS can be a useful basis for the counseling of patients with ASNHL and selection of candidates for BiCROS use.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.483-488
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• 2022

In this paper, when a gain grating and a refractive index grating exist simultaneously in a DFB laser diode having a wavelength of 1.55 ㎛, an anti-reflection coating is applied to the right mirror surface so that ρ_r=0. In case of δL<0, the characteristics of the oscillation frequency and oscillation gain have been analyzed. Whenever the phase of the grating on the left side of the mirror continuously decreases by π/2, the δL value of each oscillation mode decreases by about 0.6 to the left of the graph lines of each oscillation mode. The case of the oscillation mode having the lowest threshold gain is the case of κL=10, and in this case, the mode selectivity is relatively low compared to the case of other values of κL. From κL=0.1 to κL=6, the mode selectivity and the frequency stability are excellent. As the mode selectivity is excellent, the frequency stability is excellent. Compared to the case with two cleaved mirrors, the DFB laser diode with anti-reflection coating increases the threshold gain of the oscillation mode by about 2 times, but the mode selectivity becomes about 2 times better.

• Economic and Environmental Geology
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• v.57 no.2
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• pp.271-280
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• 2024

This study examines the European Union (EU)'s policies on managing nitrate contamination in groundwater and provides implications for the future groundwater management in South Korea. Initiated by the 1991 Nitrate Directive, the EU has pursued a multifaceted approach to reduce agricultural nitrate pollution through sustainable ('good') farming practices, regular nitrate level monitoring, and designating Nitrate Vulnerable Zones. Further policy integrations, like the Water Framework Directive and Groundwater Directive, have established comprehensive protection strategies, including the use of pollutant threshold values. Recently, the 2019 Green Deal escalated efforts against nitrates, aligning with broader environmental and climate objectives. This review aims to explore these developments, highlighting key mitigation strategies against nitrate pollution, and providing valuable insights for the future sustainable groundwater nitrate management in South Korea, emphasizing the importance of preventive measures and collaborative efforts to restore and improve groundwater quality.

• Journal of the Korea Concrete Institute
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• v.21 no.3
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• pp.245-253
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• 2009

The importance of chloride ions in the corrosion of steel in concrete has led to the concept for chloride threshold level (CTL). The CTL can be defined as the content of chlorides at the steel depth that is necessary to sustain local passive film breakdown and hence initiate the corrosion process. Despite the importance of the CTL, due to the uncertainty determining the actual limits in various environments for chloride-induced corrosion, conservative values such as 0.4% by weight of cement or 1.2 kg in 1 $m^3$ concrete have been used in predicting the corrosion-free service life of reinforced concrete structures. The paper studies the CTL for blended cement concrete by comparing the resistance of cementitious binder to the onset of chloride-induced corrosion of steel. Mortar specimens were cast with centrally located steel rebar of 10 mm in diameter using cementitious mortars with ordinary Portland cement (OPC) and mixed mortars replaced with 30% pulverized fuel ash (PFA), 60% ground granulated blast furnace slag (GGBS) and 10% silica fume (SF), respectively, at 0.4 of a free W/B ratio. Chlorides were admixed in mixing water ranging 0.0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.5, 2.0, 2.5 and 3.0% by weight of binder(Based on $C1^-$). Specimens were curd 28 days at the room temperature, wrapped in polyethylene film to avoid leaching out of chloride and hydroxyl ions. Then the corrosion rate was measured using the polarization resistance method and the order of CTL for binder was determined. Thus, CTL of OPC, 60%GGBS, 30%PFA and 10%SF were determined by 1.6%, 0.45%, 0.8% and 2.15%, respectively.

• Progress in Medical Physics
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• v.23 no.1
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• pp.8-14
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• 2012

In order to develop a Patient respiratory management system includinga biofeedback function for4-dimentional radiation therapy, this study investigated anoptimal tracking algorithmfor moving target using IR (Infra-red) camera as well as commercial camera. A tracking system was developed by LabVIEW 2010. Motion phantom images were acquired using a camera (IR or commercial). After image process were conducted to convert acquired image to binary image by applying a threshold values, several edge enhance methods such as Sobel, Prewitt, Differentiation, Sigma, Gradient, Roberts, were applied. The targetpattern was defined in the images, and acquired image from a moving targetwas tracked by matching pre-defined tracking pattern. During the matching of imagee, thecoordinateof tracking point was recorded. In order to assess the performance of tracking algorithm, the value of score which represents theaccuracy of pattern matching was defined. To compare the algorithm objectively, we repeat experiments 3 times for 5 minuts for each algorithm. Average valueand standard deviations (SD) of score were automatically calculatedsaved as ASCII format. Score of threshold only was 706, and standard deviation was 84. The value of average and SD for other algorithms which combined edge detection method and thresholdwere 794, 64 in Sobel, 770, 101 in Differentiation, 754, 85 in Gradient, 763, 75 in Prewitt, 777, 93 in Roberts, and 822, 62 in Sigma, respectively. According to score analysis, the most efficient tracking algorithm is the Sigma method. Therefore, 4-dimentional radiation threapy is expected tobemore efficient if threshold and Sigma edge detection method are used together in target tracking.