We attempted to provide an overview of the laws and current state of the 3D printing industry in South Korea and around the world, using the annual industry surveys and the Wohler report. Additionally, we reviewed articles relating to the potential exposure to hazards associated with 3D printing using metal materials. In South Korea, there were 406 3D printing-related businesses, employing 2,365 workers, and the market size was estimated at 455.9 billion won in 2021. Globally, the average growth rate of the 3D printing industry market over the past 10 years was 27.4%, and the market size was estimated at $11.8 billion in 2019. The United States had the highest cumulative installation ratio of industrial 3D printers, followed by China, Japan, Germany, and South Korea. A total of 6,168 patents related to 3D printing were registered in the US between 2010 and 2019. Harmful factors during metal 3D printing was mainly evaluated in the powder bed fusion and direct energy deposition printing types, and there is a case of material extrusion type with metal additive filaments. The number, mass, size distribution, and chemical composition of particles were mainly evaluated. Particle concentration increases during the opening of the chamber or post-processing. However, operating the 3D printer in a ventilated chamber can reduce particle concentration to the background level. In order to have a safe and healthy environment for 3D printing, it is necessary to accumulate and apply knowledge through various studies.

확산강조 자기공명영상은 초급성기 뇌경색 진단과 뇌종양 진단 및 치료에 매우 유용하지만 뇌줄기 주변에 자화 감수성 인공물이 자주 발생하고 있어 이를 최소화하려는 노력이 필요하다. 확산강조영상은 에코평면영상(echo planar image)을 사용하고 서로 다른 자화 감수성을 가진 구조물들이 인접한 경계면에서 영상의 왜곡을 나타낸다. SENSE(sensitivity encoding) 기법은 자화 감수성 인공물을 감소시킬 수 있다. 본 연구는 뇌 줄기의 해부구조를 모방한 팬텀을 만들어서 확산 강조영상 시 자화 감수성 인공물을 감소시키는 최적의 SENSE 인자(factor)를 알아보았다. 산출된 최적의 SENSE 인자와 현재 임상 값으로 만든 영상을 비교 분석하고, 통계적 유의성을 검증하여 유용성을 알아보았다. 팬텀 실험 결과 SENSE 인자의 크기가 증가할수록 자화 감수성 인공물은 감소하였다. SENSE 인자 2.5, 3.0, 3.5, 4.0을 적용한 영상은 기준 영상 과 같은 크기의 왜곡이 발생하였다. 산출된 SENSE 인자 2.5의 실험군과 1.5을 적용한 대조군 각각 40명의 영상을 비교 분석하였다. SENSE 인자 1.5를 적용한 대조군은 SENSE 인자 2.5를 적용한 실험군에 비해서 자화 감수성 인공물이 더 크게 발생하였고, 통계적으로 유의하게 나타났다. 본 연구를 통해서 뇌 확산강조영상 획득 시 SENSE 인자 2.5를 적용한다 면 진단적으로 더욱 가치가 있는 영상을 얻을 수 있을 것으로 사료된다.

There are still debated about surveillance interval, duration, diagnostic modality and treatment for intraductal papillary mucinous neoplasm (IPMN) of the pancreas. In recent guidelines, ‘high risk stigmata (HRS)’ and ‘worrisome feature (WF)’ are defined as predictive factors for malignancy in IPMN. IPMNs with HRS and main duct- IPMN are more likely to accompany malignancies, thus require surgery. However, in the case of only WF, since the risk of malignancy is different for each factor, the management decision can be variable according to the number of overlapping WFs. In addition, for segmental main pancreatic duct dilatation without enhancing mural nodules, careful surveillance might be considered rather than immediate surgery. In IPMN patients with elderly or severe comorbidities, treatment strategy should be determined based on surgical and malignant risk assessment. To date, the natural course of IPMN patients with HRS and WF is not well understood, thus further studies with a large number of patients are needed.

Complaints about foul odors are emerging as an issue, and the number of complaints is steadily increasing every year. Biofiltration is known to remove harmful or odorous substances from the atmosphere by using microorganisms, and full-scale biofilters are being installed and operated in various environmental and industrial facilities. In this study, the current status and actual odor removal efficiency of full-scale biofilters installed in publicly owned treatment facilities such as sewage, manure, and livestock manure treatment plants were investigated. In addition, the effects of design and operating factors on their efficiency were also examined. As a result, it was found that odor prevention facilities with less than 30% odor removal efficiency based on complex odors accounted for 40%-50% of the biofilters investigated. In investigating the appropriate level of operating factors on odor removal efficiency, it was found that compliance with the recommended values p lays a significant role in improving odor removal efficiency. In the canonical correlation analysis for the on-site biofilter operation and design data, residence time and humidity were found to be the most critical factors. The on-site biofilter operation and design data were analyzed through canonical correlation analysis, and the residence time and humidity maintenance were found to be the most important factors in the design and operations of the biofilter. Based on these results, it is necessary to improve the odor removal efficiency of on-site biofilters by reviewing the effectiveness of the operation factors, improving devices, and adjusting operating methods.

본 연구는 해양시설의 HNS 배출허용기준 체계에 적용 가능한 사회적 영향인자 평가방법 및 절차를 도출하는데 목적이 있다. 인천광역시 소재 해양시설 71개소로 대상으로 기업규모에 따라 대기업, 중견기업, 중소기업, 소기업으로 구분하였고, 신규 기술도입비용 은 5년간 분산하여 적용하는 경우로 추산하였다. 분석결과는 다음과 같다. 첫째, 산업분야 항목에서는 경영상부담정도를 나타내는 지표 중 매출액감소 1점, 영업이익률감소 평균 3.5점, 도산가능성 2.7점으로 평가되어, 평균 2.7점으로 ‘영향있다’로 평가되었다. 둘째, 지역경제 항목의 평가지표 중 주민보건비지출부담 4점, 관광수입손실액 4점, 어업생산량감소 2점 등 전체 평균 3.3점으로 ‘영향크다’로 평가되었 다. 평가결과 산업적인 면에서는 소기업, 중기업, 대기업 간에 미치는 영향편차가 큰데, 대기업은 영향이 거의 없었고, 소기업은 영향을 크게 받는 것으로 나타났다. 지역경제면에서는 주민보건비지출부담, 관광수입감소, 어업생산량감소 등이 지역경제에 미치는 영향은 두가 지로 구분하여 볼 수 있는데, 지역전체 GRDP에 미치는 영향은 매우적지만, 해당 종사자나 주민 개인에 미치는 영향은 영향이 큰 것으로 나타났다.

This study measured the suspended fungal concentration in indoor multiple facilities nationwide. The regions were selected as representative cities by region: Seoul, Gyeonggi (Incheon), Gangwon, Gwangju, Daejeon, and Busan. A total of 2028 regional comparisons, including department stores, schools, public toilets, libraries, and banks, subway, sports facilities and comparative analysis were conducted for each multi-use facility industry. Among the nationwide, Among the regions, the average concentration of floating mold in indoor multi-use facilities was the lowest in Busan at 394.67 CFU/m3, followed by Gyeonggi and Incheon 487.90 CFU/m3, Seoul 542.84 CFU/m3, Daejeon 809.30 CFU/m3, Gangwon 1,145.22 CFU/m3, Gwangju was 1,371.10 CFU/m3 in the order. Busan was the lowest, and Gangwon was the highest. The reason that Busan, which has a high average temperature and population density, shows a lower mold concentration than Gangwon, is that floating mold in the indoor air is not affected by the external atmospheric environment, population density, and number of facility users. Although it cannot be said that there is no influence of the atmospheric environment, it was found that the indoor environment has different characteristics from the outdoor environment. The importance of air quality management has been confirmed, and further, it is necessary to subdivide the management standards by region and multi-use facilities, and the management standards need to be converted to maintenance rather than recommendations.

본 논문은 남해안 자란만 패류양식어장에서 약 2년 동안 월별로 기초생산력, Chl. a, 영양염류, 입자유기물질과 퇴적물의 유기오 염 정도 및 생화학 조성 등 주요 양식생물의 서식환경인자의 변동특성과 상관성 등을 분석하였다. 또한, 다른 연안 어장과 기초생산력을 비교하고 어장환경관리와 관련된 정책방안을 제시하였다. 월별 평균 기초생산력은 6.43∼115.43 ㎎C m-2 hr-1 범위로 여름과 가을에 높았는 데, 가막만과 마산만 보다는 낮았고, 가로림만과 서해보다는 높았으며, 대체적으로 양식장이 많이 분포한 내만은 그 변동 폭이 상대적으 로 컸다. Chl. a를 구성하는 식물플랑크톤의 크기별 점유율이 시기별로 다소 차이가 있었고, 영양염의 고갈로 인한 식물플랑크톤의 생산력 제한은 거의 없었으나, 대부분 시기에 N/P비가 16 이하로 질소가 상대적으로 부족한 것으로 판단되었다. 수층 입자유기물질의 생화학적 조성은 탄수화물이 가장 높았으나, 반면 표층 퇴적물에서는 지질과 단백질 함량이 높았다. 퇴적물의 TOC와 AVS 농도는 만 안쪽에서 높 았고 일부 시기에는 어장환경기준을 초과한 상태였으며, C:N 비는 평균 8.1∼10.4 범위로 나타났다. 기초생산력은 Chl. a와의 상관성이 가 장 높았고, 입자물질성분 중에서는 탄소보다는 질소 및 단백질과의 상관성이 높았다. 최근 5년 동안의 수층에서의 Chl. a, DIN, DIP 농도는 감소하는 경향이었지만, 반대로 퇴적물의 오염도는 증가하는 추세였다. 자란만의 연간 기초생산력 125.9 gC m-2 yr-1, 굴 양식장 면적 4.97 ㎞2 를 고려하면 연간 식물플랑크톤으로부터 생산되는 탄소량이 약 625 ton이며, 연간 굴 생산 습중량은 약 6,250 ton으로 추정되었다.

As modern society has emerged and developed, the subway has established itself as a representative means of transportation in the city due to its speed, accuracy, and accessibility. According to the Indoor Air Quality Management Act, underground stations have established and managed the maintenance and recommendation standards for PM10, PM2.5, CO2, CO, HCHO, NO2, Rn, VOCs However, th the standards for airborne mold has not been applied for subway stations even though management for the health effect of exposure to mold is necessay. In this study, the correlation with major contributing factors was analyzed by measuring the concentration of airborne molds in the indoor air of underground stations and through literature research. It was confirmed that there was a correlation between the concentration of airborne molds in subway stations and the major contributing factors. As a result of the analysis, it was found that the concentration of airborne molds became higher as the location of the platform became deeper underground, during periods of congestion, and especially in summer. There was no significant correlation with the year of construction. Our findings indicate that appropriate management measures should be devised in response to such contributing factors.

본 연구는 딸기 온실 내부의 방대한 환경인자를 활용하여 판별분석을 실시하고 딸기의 재배 베드 단수에 따른 온실 내부의 환경인자를 분석함으로 써, 딸기 분야에서 계측된 데이터의 활용성을 높이기 위한 기초자료로 활용할 목적으로 수행하였다. 그 결과는 다음과 같다. 환경인자별(온도, 습도, 이산화탄소 농도, EC 및 pH) 동질성 검정의 유의확률은 각각 0.0001, 8.2788E-38, 4.3310E-85, 1.3001E-16 및 0.0001로서 설정한 유의수준 0.05보다 낮게 나타났다. 그리고 분석결과 판별함수식은 F(x)1 = –60.5664 -0.1339×Temperature –0.0087×Humidity +0.0018×CO2 +0.1014×EC +8.3860×pH, F(x)2 = –12.4928 +0.1963×Temperature –0.0024×Humidity +0.0254×CO2 –0.0187×EC –0.3651×pH로 도출되었다. 판별함수식의 정확도는 대상 온실 A (81.1%) 및 B (96.1%)보다 대상 온실 C (100.0%)에서 높은 것으로 나타났다. 예측 가능한 대상 온실별(A, B 및 C) 분류함수는 각각 – 1836.7035 – 2.8733×Temperature + 0.1355×Humidity + 0.4186×CO2 + 7.4351×EC + 484.5901×pH, – 1710.8369 – 2.7701×Temperature + 0.1550×Humidity + 0.3937×CO2 + 7.2482×EC + 468.1477×pH, – 2291.7125 - 3.9756×Temperature + 0.0723× Humidity + 0.4177×CO2 + 8.1961×EC + 546.8476×pH로 나타났다. 특히 판별함수식을 근거로 환경인자별 새로운 측정값이나 자료를 입력하였을 때, 특정 그룹으로 분류가 가능함으로써 데이터의 특징을 파악할 수 있다. 이러한 환경인자는 식별을 용이하게 함으로써 환경인자 측정값의 활용도를 높여주는 방법이라고 판단된다.

PURPOSES : The objective of this study is to develop regression models for surface distress (SD), rut depth (RD), and international roughness index (IRI) of Jeju Island local road by analyzing the correlations between the pavement performance and its influencing factors. METHODS : First, the differences between pavements in inland Korea and Jeju Island in terms of performance and influencing factors were investigated. Influencing factors were assigned to pavement sections on Jeju Island using the inverse distance weighting method, and the correlations between the pavement performance and influencing factors were analyzed. As a result, maximum temperature, heat wave days, annual temperature range, precipitation days, precipitation intensity, ESAL, etc. were determined as independent variables for the pavement performance prediction models. Multiple regression analysis was performed to develop the pavement performance models using the selected independent variables. RESULTS : The RD, maximum temperature, and precipitation days were determined to be the independent variables for the SD predictive model. The SD, maximum temperature, annual temperature range, heat wave days, and precipitation days were selected as independent variables of the RD prediction model. In addition, the RD, annual temperature range, heat wave days, precipitation days, and ESAL were selected as independent variables for the IRI prediction model. CONCLUSIONS : As a result of the study, an actual forecast model for SD, RD, and IRI was developed. Based on this model, it is possible to estimate the predictive value of the missing performance data in the studied interval. If the factors affecting performance are managed in terms of maintenance beyond a certain level, it can help those responsible for road maintenance to rationally select the maintenance method and timing.

This study was conducted to identify and assess key parameters affecting greenhouse gas emissions and odor intensity at a naturally ventilated dairy farm. Measurement data of greenhouse gases (CO2, CH4, N2O), odorants (NH3 and H2S), and meteorological data (wind speed, temperature, relative humidity, and solar radiation) were posited as the parameters influencing those emissions. Carbon dioxide and methane emissions correlated well to CO2-equivalent emissions and the contribution of carbon dioxide emissions (R2=0.9181) was greater than that of methane emissions (R2=0.8854). Hydrogen sulfide emissions were highly correlated with odor intensity (R2=0.9989), but the contribution of ammonia emissions to odor intensity was not significant (R2=0.0081). No correlation among CO2-equivalent and odor intensity emissions and meteorological parameters was observed. In this study, the relationship between emissions of greenhouse gases and odor intensity in a naturally ventilated dairy barn mainly depended upon carbon dioxide and hydrogen sulfide emissions. The results in this study will be helpful in the mitigation planning of greenhouse gases and odor in animal feeding operations (CFOs).

This paper analyzed the correlation between injection molding factors through correlation analysis. In addition, the decision-tree model, which is a white box model with excellent explanatory power, was used to obtain optimal molding conditions that satisfy multiple constraint conditions. First, 243 data to be used in the experiment were created through a full factorial design. Second, a correlation analysis was conducted to understand the correlation. Third, to verify the decision-tree model, the prediction performance was evaluated using RMSE. As a result, good prediction performance was confirmed. A decision-tree experiment analysis was conducted. As a result of the progress, the same results as the correlation analysis were derived. Based on the previous analysis results, optimal molding conditions were applied to CAE. As a result, the amount of deformation in the multi-cavity could be improved by about 1.1% and 2.72% while satisfying the constraint.

정부(해양수산부) 및 관계기관에서는 안전관리 취약선박의 해양안전 증진을 위한 많은 정책을 시행하고 있으나, 선박의 안전관리에 대한 위험성평가 부재로 각 제도의 효과성에 다소 아쉬움이 확인되었다. 선박의 위험성평가에 대한 국내 선행연구는 대부분 개별적 해양사고 위험성에 대한 단편적 위험성만을 취급하고 있어 포괄적 해양사고 위험성평가를 위한 새로운 방식이 필요하다. 선박의 안전관 리에 대한 포괄적 위험성평가 적용사례로 항만국통제와 노르웨이 해사국의 점검대상 선정방법이 있다. 본 연구에서는 국내 해양사고 및 등록현황의 높은 비중을 차지하고 있는 연근해어선을 대상으로 포괄적 선박안전관리 위험성평가를 위한 지표를 개발하고 적용하였다. 그 결과, 각 선박별 위험성을 계량적 수치로 확인하였고, 개별적 안전관리 취약요소의 순위를 식별하였다.

본 연구는 우리나라에서 발생된 57개의 땅밀림지를 대상으로 땅밀림의 내부요인인 지질특성을 분석하여 땅밀림지에 영향을 미치는 지질 인자를 찾아내기 위해 실시하였다. 발생한 57개소의 땅밀림지 규모는, 평균 폭 208.2 m (52.8m ~ 1,001.3m), 평균길이 200.3 m (22.1m ~ 920.6m), 평균깊이 3.9 m (0.2m ~ 47.8m)이었다. 땅밀림지의 지질 시대는 백악기가 23개소(약 40.4%)에서 가장 많이 발생하였으며, 경상누층군에서 가장 많이 발생하고 있는 것으로 나타났다. 상관분석 결과, 땅밀림이 발생한 피해지의 폭과 길이, 길이와 깊이는 1% 수준에서 유의한 정의 상관관계를 나타내었다. 지층과 주 구성암석 그리고 누층군과 지층, 주 구성암석과는 상관분석결과 1% 수준에서 유의한 정의 상관관계를 나타내었다. 땅밀림지는 퇴적암지역이 가장 많았다. 땅밀림 발생유형은 붕적토땅밀림, 풍화암땅밀림, 점질토땅밀림, 암반땅밀림 순으로 빈도가 높은 것으로 나타났다. 따라서 땅밀림이 우려되는 지질적인 요인을 가진 지역에 대해서는 개발 등에 대한 신중한 검토와 사전 조사평가가 필요할 것으로 사료된다.