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        검색결과 2,853

        82.
        2022.11 구독 인증기관·개인회원 무료
        Synthetic Aperture Radar (SAR) images are affected by noise called speckle, which is very severe and may hinder image exploitation. Despeckling is an important task that aims to remove such noise so as to improve the accuracy of all downstream image processing tasks. Many different schemes have been proposed for the restoration of SAR images. Among the different possible approaches, methods based on convolutional neural networks(CNNs) have recently shown to reach state-of-the-art performance for SAR image restoration. DnCNN(DeNoising Convolutional Neural Network) is one of the most widely used neural network architecture embedded in baseline SAR image despeckling methods. In military applications of SAR satellite image, fast processing is the most critical factor except the precision rate of the recognition. In this paper, we propose an improved DnCNN architecture for faster SAR image despeckling. The experimental results on real-world SAR images show that our proposed method takes faster processing time than the original DnCNN architecture without despeckling performance downgrade. Subjective visual inspection demonstrates that the proposed method has great potential in preserving the image signal details and suppressing speckle noise.
        83.
        2022.11 구독 인증기관·개인회원 무료
        Anomaly detection for each industrial machine is recognized as one of the essential techniques for machine condition monitoring and preventive maintenance. Anomaly detection of industrial machinery relies on various diagonal data from equipped sensors, such as temperature, pressure, electric current, vibration, and sound, to name a few. Among these data, sound data are easy to collect in the factory due to the relatively low installation cost of microphones to existing facilities. We develop a real time anomalous sound detection (ASD) system with the use of Autoencoder (AE) models in the industrial environments. The proposed processing pipeline makes use of the audio features extracted from the streaming audio signal captured by a single-channel microphone. The pipeline trains AE model by the collected normal sound. In real factory applications, the reconstruction error generated by the trained AE model with new input sound streaming is calculated to measure the degree of abnormality of the sound event. The sound is identified as anomalous if the reconstruction error exceeds the preset threshold. In our experiment on the CNC milling machining, the proposed system shows 0.9877 area under curve (AUC) score.
        84.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Moving Particle Semi-implicit (MPS) method is one of most famous method in the particle-based computational fluid dynamics field. The MPS, the state-of-art method, is simple but intuitive methodology including multi-phase and complex structure interactions problems. However, the concept of particle method may contain the physical weakness. In order to avoid physical violence, the particle number density and kernel function were employed. Despite all the efforts, the microscopic problems were not easily resolved yet. In this study, the surface tension model was developed and added into the MPS method to strengthen physical phenomena and physics laws. The simulation result with new MPS method including surface tension model was compared with corresponding theoretical results and they show good-agreement.
        4,000원
        85.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 조업기인 어업쓰레기 발생(추정)량에 대한 어업 및 해양환경 정책의 범주별 차이를 비교하고, 독립변수와 종 속변수의 상관성을 분석하는 것이다. 독립변수는 세 가지로 구분되는데, 사전 예방정책, 현행 관리정책, 사후 대응정책이다. 사전 예방정 책에는 친환경어업 지원사업, 제도적 예방활동, 물리적 차단 시설 설치가 있다. 현행 관리정책에는 관련 선박 운영, 어업질서 확립, 어업 구조조정, 어장환경 개선이 해당된다. 사후 대응정책에는 하천~해안변 쓰레기 정화, 해양·침적·부유쓰레기 수거, 조업 중 인양쓰레기 수 매, 어업관련 폐기물 처리, 해양쓰레기 피해복구가 포함된다. 측정지표는 각 사업별 결산액이다. 종속변수는 조업으로 인한 어업쓰레기 발생 추정량이고, 측정지표는 연안 통발 및 자망과 그 부속어구 유실량의 합이다. 평균순위 차이 검증결과 어업쓰레기 발생 추정량은 해 역별로는 동해안이 가장 높게 나타났고, 기초자치단체별로는 시 지역이 가장 높게 나타났다. 해양환경 관련 결산액은 군 지역에서 가장 많이 투입하고 있었고, 대부분의 변수에서 유의한 차이가 나타났다. 어업쓰레기 발생 추정량과 관련있는 변수는 사후 정책 중 조업 중 인 양쓰레기 수매 사업과 폐기물 처리 지원 사업이었다.
        4,300원
        86.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The mineral content of Tricholoma matsutake was evaluated for comparison of mineral contents according to the area of cultivation. Ten domestic and thirty Chinese (10 Yanji, 10 Yunnan and 10 Tibet) T. matsutake specimens were assessed using an atomic absorption spectrophotometer (AAS) and inductively coupled plasma mass spectrometer (ICP-MS). The Na, Mg, K, and Ca contents of domestic T. matsutake were 128.12±85.25 mg/kg, 218.52±105.35 mg/kg, 7,534.58±2,691.52 mg/kg, and 17.69±7.14 mg/kg, respectively, while those of Yanji T. matsutake were 124.89±57.24 mg/kg, 64.07±27.52 mg/kg, 1,439.18±311.04 mg/kg, and 10.88±4.52 mg/kg, respectively. The Na, Mg, K, and Ca contents of Yunnan T. matsutake were 90.78±23.23 mg/kg, 77.40±28.36 mg/kg, 1,446.29 ±126.33 mg/kg, and 28.42±5.18 mg/kg respectively, while those of Tibet T. matsutake were 143.50±41.54 mg/kg, 124.64±50.18 mg/kg, 3,530.95±2,714.99 mg/kg, and 21.05±8.71 mg/kg, respectively. The Cu contents of domestic, Yanji, Yunnan, and Tibet T. matsutake were 105.43±32.97 mg/kg, 19.92±8.95 mg/kg, 54.51±16.91 mg/kg, and 64.80±23.01 mg/kg, respectively. Both domestic and Chinese T. matsutake samples showed significantly different K, Mg, and Cu levels in this study. Therefore, a comparative evaluation of the K, Mg, and Cu contents of multiple domestic and Chinese T. matsutake varieties is needed to determine the appropriate area of cultivation in the future.
        4,000원
        87.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to overcome the small scale of Korea waterworks and to achieve comprehensive improvement and innovation transformation, the waterworks integration was reviewed. The effect of consolidation was confirmed by the integration of the water supply business in the southern Gangwon region and the western Gyeongnam region in Korea, such as an increase in the flow rate and a decrease in the production unit cost. After facing management and service limitations overseas, more than 1,000 small-scale waterworks projects in the UK were integrated into 27 waterworks providers, and Japan also revised the Waterworks Act in December 2019 and is in the process of integrating waterworks. It is considered appropriate to promote the integration of waterworks projects in Korea by respecting the autonomy of local governments, but using a participatory method, a win-win method, and a linkage method. For the integration of waterworks projects, three strategies are proposed: First creating a national foundation for integration (revision of the Waterworks Act), Second establishing a waterworks integration strategy led by local governments, Third forming an external consensus and providing incentives for participation.
        4,500원
        88.
        2022.10 KCI 등재 구독 인증기관·개인회원 무료
        송국리형 주거지의 이용 및 폐기과정은 청동기시대의 흥미로운 연구 과제 중 하나이며, 특히 내부 흑색토층의 존재는 많은 관심을 끌어왔다. 송국리 유적 제24차와 25차 발굴조사에서 내부 흑색토층 이 확인된 주거지(98호, 100호, 107호)를 대상으로 환경고고학적 연구(토양 미세형태분석 및 규소체 분석)를 수행하였다. 토양 미세형태분석 결과, 내부 흑색토층은 탄화물이 집적된 층으로 보이며 탄화 가 비교적 가까운 곳에서 일어났을 가능성을 시사한다. 아마도 지붕이나 벽체를 비롯한 상부 구조물 이 탄화되어 집적된 층일 가능성이 높다. 한편 100호 주거지의 규소체분석 결과, 중간 흑색토층 및 상부 퇴적토에서 벼와 조의 규소체가 다량으로 확인되었다. 그리고 사초과 식물의 규소체와 해면동물 골편이 출토된 것으로 보아 저지대(예, 수전) 토양을 벽체 등의 건축재로 사용했던 것으로 보인다. 또 한, 내부 흑색토층이 보이는 주거지와 수혈유구는 연접한 경우가 많아, 화재에 의한 탄화물이 주거지 와 인근 수혈 내부로 흘러 들어간 것으로 생각된다. 이를 종합하여 보면 일부 주거지는 사용이 중지된 이후, 기둥과 같은 주요 건축재를 해체하여 반출한 다음 재활용이 어려운 나머지 잔존 구조물을 소각 했던 것으로 보인다. 그리하여 탄화물이 집적되어 수혈 중간부에 흑색토층을 생성했던 것으로 추정된 다. 본 연구에서는 토양 미세형태분석과 규소체분석이 상호보완적으로 함께 수행되어 해석의 지평을 넓힐 수 있었다.
        90.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Roller-compacted concrete pavement (RCCP) is a superstiff-consistency concrete pavement that exhibits excellent strength development owing to a hydration reaction and interlocking aggregates owing to the roller compaction. A zero-slump concrete mixture is generally used. Hence, it is important to control the consistency of the RCCP mixture to prevent the deterioration of the construction quality (such as material separation during paving). The workability of the RCCP is characterized by its consistency and controlled by the Vebe time, whereas a conventional concrete pavement is controlled based on the slump test. The consistency of the RCCP changes over time after concrete mixing owing to delivery, construction time delays, etc. Thus, it is necessary to use the optimum Vebe time to achieve the best construction quality. Therefore, this study aims to develop a Vebe time prediction model for efficiently controlling the consistency of RCCPs according to random time variations. METHODS : A Vebe time prediction model was developed using a multiple linear regression analysis. A dataset of 131 samples was used to develop the model. The collected data consisted of variables with large potential effects on the consistency of the RCCP, such as the water-cement ratio (W/C), sand/aggregate ratio (S/a), water content (ω), water content per unit volume (W), cement (C), fine aggregate (S), coarse aggregate (G), water reducing admixtrue (PNS), air-entraining admixture (AE), delay time (T), air temperature (TEM), and humidity (HUM). In the multiple linear regression analysis, the mentioned parameters were used as the independent variables, and the Vebe time was the dependent variable. The Vebe time prediction models were evaluated by considering the adjusted R2 and p-values. The selection of the model was based on the largest R2 value and an acceptable p-value (p<0.05). RESULTS : The Vebe time prediction model achieved an adjusted R2 value of 64.14% with a significance level (p-value) of less than 0.05. This shows that the predictive model is adequately described for the dependent variable, and that the model is suitable for Vebe time predictions. Moreover, the significance level of the independent variables is less than 0.05, indicating significant effects on the Vebe time (i.e., the dependent variable). CONCLUSIONS : The Vebe time prediction model developed in this study can be used to estimate Vebe times with an R2 of 63.33% between the measured and predicted values. The proposed Vebe time prediction model is expected to be effectively utilized for the quality control of RCCP mixtures. Moreover, it is expected to contribute to achieving good RCCP construction quality.
        4,000원
        91.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ethyl formate (EF) is a potent fumigant replacing methyl bromide. The use of EF is limited to a quarantine process. Appling EF to agricultural field as a safe insecticide in greenhouse give us valuable benefits including less residual concern. In this regard, residual pattern after EF fumigation in greenhouse should be undertaken. In the previous study, we have established agricultural control concentration of EF to control pests in a greenhouse. EF was fumigated at 5 g m-3 level for 2 h. The concentration of EF inside a greenhouse was analyzed to be 4.1-4.3 g m-3 at 30 min after fumigation. To prepare an analytical method for residues in cucumber crops and soil in the greenhouse, the limit of detection (LOD) of the method was 100 ng g-1 and the limit of quantitation (LOQ) of this method was 300 ng g-1. R2 values of calibration curves for crops and soil were 0.991-0.997. In samples collected immediately after ventilation, EF concentration was determined to be below LOQ level. In addition, EF level was below LOQ in samples collected at 3 h after ventilation except that leaf samples of melon during the flowering period showed a level of 1,068.9 ng g-1. Taken together, these results indicate that EF used in quarantine can be applied to agricultural fields without residual issue as an effective fumigant for insect pest control.
        4,000원
        93.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, 3D printing has been actively studied. A representative material in this 3D printing technology is plastic, and PLA, an eco-friendly material, is widely used. FDM is widely used as a way to output these PLA materials. However, this method lacks mechanical properties compared to injection-molded products as it is a method of stacking materials by melting. Therefore, in this study, using an FDM-type 3D printer, a tensile test was performed after printing a tensile specimen with PLA filament with the layer angle and layer density as control factors. After that, changes in tensile properties according to the layer angle and density were compared and evaluated. As a result, to improve the tensile strength, the layer density had to be considered, and to improve the elastic modulus, both the layer angle and the layer density had to be considered.
        4,000원
        94.
        2022.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, an Co/Fe coated porcelain using a cobalt and ferrous sulfate was sintered at 1,250 oC. The specimens were investigated by HR-XRD, FE-SEM (EDS), Dilatometer, and UV-vis spectrophotometer. The surface of the porcelain was uniformly fused with the pigment, and white ware and celadon body specimens were densely fused to a certain thickness from the surface. Other new compounds were produced by the chemical reaction of cobalt/ferrous sulfate with the porcelain body during the sintering process. These compounds were identified as cobalt ferrite spinel phases for white ware and white mixed ware, and an andradite phase for the celadon body, and the amorphous phase, respectively. As for the color of the specimens coated with cobalt and ferrous mixed pigments, it was found that the L* value was greatly affected by the white ware, and the a* and b* values were significantly changed in the celadon body. The L* values of the specimens fired with pure white ware, celadon body, and white mix ware were 72.1, 60.92, 82.34, respectively. The C7F3 pigment coated porcelain fired at 1,250 oC had L* values of 39.91, 50.17, and 40.53 for the white ware, celadon body, and white mixed ware, respectively; with a* values of -1.07, -2.04, and -0.19, and at b* values of 0.46 and 6.01, it was found to be 4.03. As a new cobalt ferrite spinel phase was formed, it seemed to have had a great influence on the color change of the ceramic surface.
        4,000원
        95.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 간호대학생의 성장마인드셋과 임상실습 감정노동이 간호전문직관에 미치는 영향을 파악하고자 수행된 서술적 조사연구이다. 연구대상은 G시의 2개 대학 간호학과에 재학 중인 3, 4학년 학생 이며 자료는 2021년 7월부터 9월까지 수집하였다. 자료는 기술적 통계, t-test, ANOVA, Pearson 상관계 수, 통제회귀분석으로 분석하였다. 연구결과는 다음과 같다. 성장마인드셋은 간호전문직관(β=.325, p<.001)에 정적인 영향을 나타냈고 임상실습 감정노동은 간호전문직관(β=-.099, p=.161)에 통계적으로 영향을 나타내지 않았다. 연구모형은 간호전문직관을 25.4% 설명하는 것으로 확인되었다. 이에 간호대학 생의 간호전문직관을 촉진하기 위해서는 성장마인드셋을 강화시키는 전략들이 필요함을 알 수 있다.
        4,000원
        96.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 우리나라에 태풍이 내습할 때 먼저 피해를 받는 남해안 지역을 대표하는 Quantile을 제안하고, 각 지점들의 재 현기간에 따른 극치 풍속을 추정하기 위하여 연 최대풍속 자료와 Hosking이 제안한 선형-모멘트 방법(L-moments)을 이용한 지역빈도 해석을 수행하였다. 모든 기상관측 지점에서는 비정상적인 값이 존재하지 않았고 이질성 검정을 통해서 하나의 동질 한 지역을 나타 낼 수 있음을 확인하였다. 또한 적합도 과정을 통해서 Generalized Normal (GNO) 및 Generalized Extreme Value(GEV) 분포를 남해안 지역을 대표하는 빈도분포로 선택하였다. 상대 오차(RB)와 상대 평균제곱근 오차(RRMSE)를 이용하여 두 분포의 안정성을 평가한 결 과, GNO 분포가 GEV 분포보다 더 안정한 것을 알 수 있었다. 마지막으로 남해안 지역을 대표하는 Quantile과 각 지점들의 평균, 중앙 값, 그리고 위치 매개변수를 이용하여 지점들의 극치 풍속을 추정하였다. 본 연구에서 적용한 지역빈도해석이 자료가 부족하거나 계측 되지 않은 지점들에 대한 극치 풍속을 추정하기 위한 방법으로서 도입이 필요하다고 생각된다.
        4,000원
        97.
        2022.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Probiotic strain is known to regulate the immune system by colonizing in the intestine and interact with intestinal cell receptors of lymphoid tissue. In this study, safety of Streptococcus thermophilus KCTC14471BP and silk fibroin coating effects was evaluated with respect to mucin binding abilities and immune system modulation. S. thermophilus KCTC14471BP was coated with silk fibroin by adding 1% water-soluble calcium and 0.1% silk fibroin. S. thermophilus KCTC14471BP showed the high activities of leucine arylamidase and β-galactosidase. Regarding the antibiotic resistance tests, S. thermophilus KCTC14471BP was susceptible to ampicillin, vancomycin, gentamicin, kanamycin, streptomycin, erythromycin, clindamycin, tetracycline, and chloramphenicol. S. thermophilus KCTC14471BP coated with silk fibroin showed the improved mucin binding ability from 16.1% to 71.3% and was confirmed to have no cytotoxicity against RAW 264.7 macrophage. S. thermophilus KCTC14471BP coated with silk fibroin showed dose-dependently significant increases in pro-inflammatory cytokines IL-1β, IL-6, and TNF-α. These results suggested that S. thermophilus KCTC14471BP can be expected as a promising probiotic bacteria for applications to food industries such as fermentation or functional foods.
        4,000원
        100.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Preventive pavement maintenance is an economical and efficient method of infrastructure management. This study aims to improve the performance of cold thin-layer asphalt pavement, which is mainly used in earthwork pavement, and for bridge overlays and structures. METHODS : A cold asphalt mixture of modified emulsified asphalt and RAP was prepared for cold recycled thin-layer asphalt pavement. The performance of the mixture as a function of fiber reinforcement to improve flexural strength and crack resistance was evaluated. RESULTS : The use of RAP aggregate in cold asphalt mixture was found to increase the cohesive strength of the mixture and improve the wet abrasion resistance due to the effect of the residual binder. As a result of the loaded wheel test and flexural tension test with the addition of fiber reinforcement, it was found that the crack resistance of 0.4 % glass fiber was the best, and especially, the flexibility at low temperature was excellent. CONCLUSIONS : The cold recycled thin-layer asphalt pavement mixture has improved cohesive strength, flexural strength, and crack resistance compared to existing cold asphalt pavement materials, so it will contribute to economical and effective maintenance in preventive maintenance of bridge overlays and structural pavements.
        4,000원
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