of actual and suspicious black-ice cases that occurred during the last 10 years in the Republic of Korea. METHODS : Based on literature review, meteorological observation data associated with black-ice formation are selected: wind speed, air temperature (T), dew point temperature (Td), and relative humidity, to set minimum or maximum threshold values based on the normal distribution of each variable. In addition, weights are assigned based on the relationship among the variables to calculate the probability of occurrence. RESULTS : The threshold values are calculated using the average and standard deviation, resulting in 7.65 °C, 56.63%, 2.99 ms-1 for T-Td, relative humidity, and wind speed, respectively. Whereas the threshold value of T-Td and wind speed is set to the maximum threshold, that of the relative humidity is set to the minimum threshold value. These threshold values are applied to the diagnosis algorithm of black-ice formation, including a 1-h accumulated precipitation. CONCLUSIONS : The algorithm is expected to be utilized as a research methodology for diagnosing suspected cases of black ice.

In general, small and medium-sized computer rooms do not have access floors for reasons of increased floor height and increased construction cost. Therefore, the air conditioning method used here applies the method of directly blowing the cold air of the air conditioner into the computer room. In this case, the hot/cold air is not separated, and as the hot air is recirculated, it is re-introduced to the front of the server rack, resulting in a problem that the server cooling efficiency is decreased. In addition, in such a computer room structure, it is difficult to configure and install a containment system. In this study, we tried to understand the problem of the formation airflow in the case of using the existing air conditioning method, and to find a method of configuring the air conditioning environment to improve the cooling efficiency. The purpose of this study was to understand the airflow/temperature distribution in the computer room using the CFD simulation method. In addition, the thermal characteristics of various air-conditioning environments such as the location of the CRAC cold air discharge location, the layout between server rack and CRAC and the containment were reviewed.

본 연구는 부산광역시를 대상으로 열환경을 개선하기 위한 바람길 관리 방안 제안을 목적으로 한다. 이를 위해, Landsat-7 위성 열영상 자료와 공간통계 분석을 실시하여 부산광역시의 Hot spot과 Cool spot 지역 특성을 파악하였으며, WRF 기상모의를 통해 주요 바람길을 분석하였다. 그 결과, Hot spot 지역 중 열환경 개선이 요구되는 지역은 부산진구, 동래구, 연제구와 사상구 공업지역, 대규모 시설지역에는 부산항 부두로 나타났으며 주요 바람길에는 금정산~백양산~ 구덕산 계곡부로서 확인되었다. 이를 바탕으로 바람길 관리 전략을 제시하면 다음과 같다. 공업시설과 부산항 일대는 대기 온도 상승 요인으로서 주변 지역의 열환경을 악화시키므로 시설의 온도저감 및 바람길을 고려한 도시·건축계획이 요구된다. 바람길 관리가 필요한 지역으로 만덕동, 사직동 일대 산림에 대한 추가적인 훼손이 일어나지 않도록 하여야 하며, 산림과 인접한 지역의 대규모 고층아파트는 산림에서 생성된 차고 신선한 공기의 흐름을 방해하므로 금정산과 접해있는 제3종 일반주거지역의 신규·재개발에 따른 고층아파트 단지 조성은 지양해야 한다. 본 연구 결과는 부산광역시의 기후변화에 대응한 도시계획 및 환경계획수립 시 기초자료로 활용할 수 있을 것으로 기대한다.

Institutional foodservice is a type of meal provided to workers in industry and affects the health and psychological wellbeing of workers and productivity. Thus, research on customer satisfaction with institutional foodservice is important. In addition to food industry and food culture developments, the requirements of institutional foodservice customers are diversifying due to COVID-19. Therefore, the purpose of this study was to identify factors that affect customer satisfaction with institutional foodservice using a user-based approach. In this study, the quality of institutional foodservice was defined using customer satisfaction or dissatisfaction, and by using in-depth interview and open coding (a qualitative research method), we derived qualities of institutional foodservice from the user’s perspective and compared these with those of previous studies. This study is meaningful as the quality of institutional foodservice was analyzed using a user-based approach, in-depth interview, and open coding and compares results with those of previous studies.

고창 표준기상관측소(Gochang Standard Weather Observatory, GSWO)에서 3년간(2014-2016년) 관측한 겨울철 강수량 자료를 사용하여 겨울철 관측환경에 따른 강수량 관측 특성을 분석하였다. 이를 위해, 설치환경이 다른 강수량 계 4종인 NS(No Shield), SA(Single Alter), DFIR(Double Fence Intercomparison Reference), PG(Pit Gauge)를 사용하여, DFIR을 기준으로 누적 강수량 차이, 강수 유형별 특성, 풍속 변화에 따른 수집효율을 분석하였다. 강수 유형은 고창 종관기상관측장비(Automated Synoptic Observing System, ASOS)의 기온 관측 자료를 사용하여 강우, 혼합 강수, 강설로 분류하여 분석하였다. 겨울철 누적 강수량은 SA, NS, PG 순으로 DFIR과 유사하게 나타났으며, 통계 분석 결과에서는 SA가 DFIR과 가장 유사한 결과를 보였다. 결과적으로, 겨울철 강수량 관측에서는 SA가 기준 강수량계와 가장 유사하게 관측되었으며, PG는 겨울철 관측에 적합하지 않은 것으로 분석된다.

본 연구에서는 하절기 토마토 재배 시 주간 포그 냉방, 야간 히트펌프 냉방을 처리를 하여 냉방 처리가 온실 내 온습도, 작물의 생육 및 수확량에 미치는 영향을 분석하였다. 하절기 주간에 차광 처리한 대조구 온실의 평균 온습도는 32.1°C, 59.4%였고, 포그 처리한 시험구 온실의 평균 온도는 30.0°C, 74.3%로 나타났다. 이 때 외부의 평균 온습도는 31.4°C, 57.7%로 대조구 온실의 온도는 외기보다 0.7°C 높았으나 시험구 온실의 온도는 외기보다 1.4°C, 대조구보다 2.1°C 낮게 나타났다. 평균 습도는 시험구 온실 74.3%, 대조구 온실 59.4%로 포그 처리를 한 시험구에서 높게 나타났다. 야간 대조구 온실의 평균 온습도는 25.2°C, 85.1%였고, 히트펌프로 냉방을 한 시험구 온실의 평균 온습도는 23.4°C, 82.4%, 로 나타났다. 야간 외부의 평균 온습도는 24.4°C, 88.2%로 대조구 온실의 온도는 외기보다 0.8°C 높았으나 시험구 온실의 온도는 외기보다 1.0°C, 대조구보다 1.8°C 낮게 나타났다. 평균 습도는 시험구 온실 82.4%, 대조구 온실 85.1%로 나타나 시험구 온실의 습도가 더 낮게 나타났다. 작물 생육은 정식하고 8주 후에는 두 온실 간의 큰 차이는 없는 것으로 나타났으나 냉방 처리 후에는 시험구 온실의 작물이 대조구에 비해 경경, 초장, SPAD 값이 높게 나타났다. 토마토의 수확량은 냉방을 시작하고 2주 후까지 총 생산량의 차이는 1.2%로 큰 차이 없었으나 3주 후와 4주 후의 일 생산량이 시험구에서 대조구보다 많게 나타났다. 최종적으로는 시험구의 수확량이 81.3kg, 대조구의 수확량이 73.8kg으로 시험구가 대조구에 비해 10.2% 많게 나타남으로써 하절기 주간 포그 냉방, 야간 히트펌프 냉방이 작물 성장에 적합한 환경을 조성해 줌으로써 생육 및 생산성에 영향을 미친 것으로 판단된다. 냉방 처리에 따른 경제성을 비교해보면 대조구 온실에서는 142,166원의 수익이 있었던 반면 시험구 온실에서는 28,727원의 손해가 발생하여 냉방 처리는 경제성이 떨어지는 것으로 나타났다. 그러나 재식 밀도, 히트펌프 운용 시간 및 기간을 조절하여 에너지 사용은 줄이면서 생산성을 증가시킨다면 경제성도 확보할 수 있을 것으로 기대되며 이에 대한 추가 연구가 필요할 것으로 판단 된다.

PURPOSES : The objective of this study is to analyze the uniform diffusion mechanism of precursor gas species, and the effect of NOx reduction technology in a full-scale particulate matter testing facility, using computational fluid dynamics (CFD). METHODS : A full-scale environment chamber was constructed to evaluate the effects of particulate matter reduction technologies on the road. CFD analysis was conducted to simulate the road environment conditions in the chamber, and investigate the effect of the NOx removal panel. The time required to reach the NOx concentration to target value in the fluid field was determined at a given inflow velocity, inlet direction, and initial inflow concentration. The effect of the NOx removal panel, and solar energy on the reduction characteristics of the NOx concentration in the environment chamber was analyzed. RESULTS : The inflow velocity was determined to be the major factor affecting the time required to reach a uniform target NOx concentration in the environment chamber. The inlet location in the transverse direction requires additional time to approach the uniform target concentration, than the longitudinal direction at the same inflow velocity. Based on the CFD analysis in the 1ppm concentration condition of the chamber, a two-fold increase in the NOx removal panel efficiency can reduce the time to target concentration by approximately 50%. It is also observed that a 20% increase in solar energy can decrease the time to target concentration by 4%–12% depending on the panel efficiency. CONCLUSIONS : This study proved that a full-scale environment chamber can be effectively utilized to evaluate the particulate matter reduction technologies applied in road facilities

In addition to physical risks such as electrical, chemical, and mechanic ones in the workplace, psychosocial risks are also raising as an important issue in recent years in connection with human rights and work-life balance policies. The purpose of this study is to confirm the degree of effect of the psychosocial risk management plan at the workplace on workers through logistic regression analysis. Input data for logistic regression analysis is the results of a survey of 4,558 people conducted by the Institute for Occupational Safety and Health were used. There are 9 independent variables, including the change a workplace and confidential counseling, and the dependent variable is whether the worker feels the effect on the psychosocial risk management plan. As a result of this study, changes in work organization, dispute resolution procedures, provision of education program, notification of the impact of psychosocial risks on safety and health, and the persons in charge of solving psychosocial problems are shown effective in reducing worker’s psychosocial risks. This study drives which of the management plans implemented to reduce the psychosocial risk of workers in the workplace are effective, so it can contribute to the development of psychosocial risk management plans in the future.

This study was conducted to determine whether the layout of wheelhouse and work environment of coastal improved stow net fishing boats affect the physical abnormalities of wheelhouse workers through a survey and to use it as basic data to improve the wheelhouse work environment. The analysis results are as follows. The result of factor analysis on the wheelhouse work environment was classified into three factors: suitability of work environment, suitability of work space arrangement, and layout of navigational and fishing equipment. The result of factor analysis on physical abnormalities was divided into two factors: physical pain and fatigue. The results of regression model analysis showing factors affecting physical pain showed that the t-value in the regression model was 3.625 (p < 0.05), indicating that the work environment suitability had an effect on the physical pain. Work environment suitability had a significantly positive effect on the physical pain. As work environment suitability increased by 1, the physical pain increased by 0.371 (p < 0.05). The results of regression model analysis showing the influencing factors on fatigue were found to have a t-value of 3.009 (p < 0.05) in the regression model, indicating that the work environment suitability had a significantly positive effect on the feeling of fatigue. It was found that fatigue increased by 0.324 (p < 0.05) as the work environment suitability increased by 1. In addition, the manageability of task suitability was found to be t = –2.521 (p > 0.05). As the manageability of task suitability increased, the skipper’s fatigue level decreased. From these results, it is inferred that the wheelhouse of the current coastal improved stow net fishing boats causes physical pain and fatigue for the skippers. In order to reduce such physical pain and fatigue, and to improve safe fishing operation and job satisfaction, it is necessary to provide a wheelhouse to fishermen on coastal improved stow net fishing boats in consideration of the characteristics of the wheelhouse work of fishing boats and in consideration of users.

This study was conducted to analyze changes in the policy environment in the Jeju area in terms of conflict management by local governments and to derive the need to introduce policies for conflict management. According to this study, the policy environment in the Jeju area has been constantly changing to make it easier for conflicts to occur: First, the Jeju community has been suffering from public conflict since the past due to a number of large-scale development projects. Second, the increase in population has led to the diversification of stakeholders in society, which has resulted in complicated conflict situations. Third, conflict management keywords have begun to appear directly in election announcements, which means that many local residents perceive conflict itself as an important policy agenda. In order to actively address this situation, we need to utilize the concept of ‘Social capital’. Social capital is a concept that can effectively connect various individuals or groups in the region, effectively a connecting local governments and residents and ultimately helping develop the region.

절화 국화 ‘백마’를 재배하고 있는 관행농가와 스마트팜의 시설현황, 재배환경, 절화생육 및 경영성과를 비교 분석하였 다. 관행농가는 비닐하우스에서 토경으로, 스마트팜은 유리온 실에서 양액재배하고 있었다. 스마트팜은 광량, 온도, 습도, CO2, 풍속, 강우, 양액 pH와 EC 측정을 위한 센서들을 갖추어 자동제어하고 있었으며, 실시간으로 컴퓨터와 휴대전화 어플 리케이션을 이용하여 온실을 관리하고 있었다. 반면에 관행농 가는 환경 측정용 센서와 관비재배용 pH와 EC 센서들이 전혀 없었고, 모든 시스템들을 수동으로 작동하고 있었다. 시설 내의 주간과 야간온도는 관행농가에서 생육 적온보다 낮게 관리되고 있었다. 관행농가의 토양 EC는 3.2dS･m-1로 높게 나타나 절화 생육에 적합하지 않은 것으로 나타났고, 스마트팜은 1.1dS･m-1 로 적절하게 관리하고 있었다. 재배방법에 있어서 토양소독은 관행농가에서는 실시하지 않았으며, 스마트팜에서는 과산화수 소를 이용하여 토양소독을 실시하고 있었다. 그 외에 재배방 법은 큰 차이가 없었으나, 관행농가에서 응애가 많이 발생하 여 피해증상이 나타났다. 절화장, 화폭, 생체중, 엽록소 함량 등과 같은 절화 생육은 관행농가보다 스마트팜에서 더 양호한 것으로 나타났다. 경영성과 측면에서 1,000m2 기준으로 순이 익은 관행농가에서 -419천원이었고, 스마트팜은 4,484천원이 었으며, 생산량과 수취가격이 관행농가보다 스마트팜에서 각 각 22%와 52% 더 높은 것으로 나타났다. 이와 같은 절화의 생육과 경영성과의 차이는 스마트팜의 자동화 설비에 의해 정 밀 생육관리가 가능했기 때문이라고 판단되었다.