To obtain information on the indoor air quality of un-disinfected libraries used for paper records preservation, temperature, humidity, and bacterial concentration and species were investigated at five un-disinfected libraries from May to September in 2019 in the National Archives, Seoul (Nara Repository), Korea. Temperature and humidity of all the five un-disinfected libraries were well maintained at 18-22oC and 40-55% in compliance with the National Archives Paper Records Preservation Environment Standard. Bacterial concentration ranged from 2 CFU/m3 up to 280 CFU/m3 which were lower than the Korean indoor air quality standard value. A total of 68 bacterial species belonging to 33 genera were identified from indoor air of the five un-disinfected libraries. Among the 33 genera, Bacillus, Micrococcus, and Staphylococcus were the major genera. Only Micrococcus yunnanensis, Roseomonas mucosa, and Moraxella osloensis were commonly found among the five un-disinfected libraries. Bacterial species producing colonies with color on TSA media were present. Among the 68 species, Bacillus circulans and B. megaterium known to produce cellulases were found. There were also 17 species which have harmful effect on human health. The results of this study indicate that continuous monitoring of air borne bacteria is necessary in the un-disinfected libraries used for paper records preservation.

본 연구는 선박용 공기압축기의 상태기반보전 시스템에 필요한 이상치 탐지 알고리즘 적용에 대한 실험적 연구로서 고장모사 실험을 통해 시계열 전류 센서 데이터를 이용한 이상탐지 적용 가능성을 확인하였다. 고장 유형 10개에 대해 실험실 규모의 고장 모사 실험을 수행하여 정상 운전데이터와 고장 데이터를 구축하였다. 실험 결과 구축된 이상탐지 모델은 시계열 데이터의 주기에 변화를 유발하는 이상은 잘 탐지하는 반면 미세한 부하 변동에 대한 탐지 성능은 떨어졌다. 또한 오토인코더를 이용한 시계열 이상탐지 모델은 입력 시 퀀스의 길이와 초모수 조정에 따라 이상 탐지 성능이 상이한 것으로 나타났다.

Eutrophication and algal blooms can lead to increase of taste and odor compounds and health problems by cyanobacterial toxins. To cope with these eco-social issues, Ministry of Environment in Korea has been reinforcing the effluent standards of wastewater treatment facilities. As a result, various advanced phosphorus removal processes have been adopted in each wastewater treatment plant nation-widely. However, a lot of existing advanced wastewater treatment processes have been facing the problems of expensive cost in operation and excessive sludge production caused by high dosage of coagulant. In this study, the sedimentation and dissolved air flotation (SeDAF) process integrated with sedimentation and flotation has been developed for enhanced phosphorus removal in wastewater treatment facilities. Design and operating parameters of the SeDAF process with the capacity of 100 m3/d were determined, and a demonstration plant has been installed and operated at I wastewater treatment facility (located in Gyeonggi-do) for the verification of field applicability. Several empirical evaluations for the SeDAF process were performed at demonstration-plant scale, and the results showed clearly that T-P and turbidity values of treated water were to satisfy the highest effluent standards below 0.2 mg/L and 2.0 NTU stably for all of operation cases.

Numerical analysis has been carried out to investigate the flow field characteristics for exhaust gas in automobile engine DPF system. The DPF system performance is largely affected by exhaust gas flow while it passes through the complicated geometry of DOC/DPF system, fan shape structure, and perforated can with air for fuel combustion. Hence the characteristics of fluid velocity, pressure, and streamline are analyzed with velocity uniformity in front of DOC and swirl flow near the fan. It can be seen that the velocity uniformity increases with the gas flow rate including flow acceleration near the lower area of the fan. The air flow also influences the gas flow distribution close to the impeller and fan structure with complicated swirl flow. These results are expected to be applicable as fundamental design data for automobile engine exhaust system.

To remove phosphorus from the effluent of public wastewater treatment facilities, hundreds of enhanced phosphorus treatment processes have been introduced nationwide. However, these processes have a few problems including excessive maintenance cost and sludge production caused by inappropriate coagulant injection. Therefore, the optimal decision of coagulant dosage and automatic control of coagulant injection are essential. To overcome the drawbacks of conventional phosphorus removal processes, the integrated sedimentation and dissolved air flotation(SeDAF) process has been developed and a demonstration plant(capacity: 100 m3/d) has also been installed. In this study, various jar-tests(sedimentation and / or sedimentation·flotation) and multiple regression analyses have been performed. Particularly, we have highlighted the decision–making algorithms of optimal coagulant dosage to improve the applicability of the SeDAF process. As a result, the sedimentation jar-test could be a simple and reliable method for the decision of appropriate coagulant dosage in field condition of the SeDAF process. And, we have found that the SeDAF process can save 30 – 40% of coagulant dosage compared with conventional sedimentation processes to achieve total phosphorus (T-P) concentration below 0.2 mg/L of treated water, and it can also reduce same portion of sludge production.

이 연구는 한국, 중국, 일본의 국제항공 네트워크의 구조적 차이를 파악하기 위해 각 국의 주요 공항 및 국적 항공사 네트워크를 대상으로 비교분석을 실시하였다. 공항과 항공사 네트워크의 연결성을 파악하기 위해 연결·매개·근접 중심성, 네트워크 밀도, 동류성(Assortativity) 등 네트워크 분석의 다양한 지표들이 활용되었다. 주요 분석 결과는 다음과 같다. 먼저 아시아 공항들을 대상으로 국제노선 네트워크의 중심성 순위 분석 결과, 인천공항은 연결, 매개, 근접 중심성 측면에서 아시아 최상위권에 위치하였 다. 이와 더불어, 동북아와 중국 간 국제노선 네트워크가 조밀해짐에 따라 양 지역의 2차 허브공항들을 중심으로 3개 중심성 순위가 2015년 대비 급속하게 상승하였다는 점을 발견하였다. 다음으로 한국, 중국, 일본의 주요 공항 간 국제항공 네트워크 비교 결과, 우리나라는 인천 중심의 단일 허브 네트워크가 발달함에 따라 인천과 나머지 국제공항 간 중심성 격차가 복수의 허브를 운용하는 중국과 일본에 비해 매우 크게 나타나고 있었다. 다만, 국적 LCCs(Low Cost Carriers)의 경우 지역공항을 2차적 거점으로 활용함에 따라 인천공항에 대한 국제노선 집중도가 FSCs(Full Service Carriers)에 비해 상대적으로 낮게 나타났다. 본 연구를 통해 국가공항체계의 불균형을 완화하고, 지방 거주민들의 국제선 접근성 및 이용 편의성을 향상시키기 위한 전략으로 LCCs를 통한 지방국제공항들의 국제 연결성 강화 전략이 지속적으로 추진될 필요가 있다는 점을 확인하였다.

Human and material resource planning is one representative example of Operations Research. Resource planning is important not only in civilian settings but also in military ones. In the Air Force, flight scheduling is one of the primary issues that must be addressed by the personnel who are connected to flight missions. However, although the topic is of great importance, relatively few studies have attempted to resolve the problem on a scientific basis. Each flight squadron has its own scheduling officers who manually draw up the flight schedules each day. While mistakes may not occur while drafting schedules, officers may experience difficulties in systematically adjusting to them. To increase efficiency in this context, this study proposes a mathematical model based on a binary variable. This model automatically drafts flight schedules considering pilot’s mission efficiency. Furthermore, it also recommends that schedules be drawn up monthly and updated weekly, rather than being drafted from scratch each day. This will enable easier control when taking the various relevant factors into account. The model incorporates several parameters, such as matching of the main pilots and co-pilots, turn around time, availability of pilots and aircraft, monthly requirements of each flight mission, and maximum/minimum number of sorties that would be flown per week. The optimal solution to this model demonstrated an average improvement of nearly 47% compared with other feasible solutions.

Economic indicators are a factor that affects air cargo volume. This study analyzes the different factors affecting air cargo volume by each Chinese cities according to the main characteristics. The purpose of this study is to help companies related to China, airlines, and other stakeholders predict and prepare for the fluctuations in air cargo volume and make optimal decisions. To this end, 20 economic data were used, and the entire data was reduced to 5 dimensions through factor analysis to build a dataset necessary and evaluated the influencing factors by multi regression. The result shows that Macro-Economic Indicators, Production/Service indicators are significant for every cities and Chinese manufacture/Customer indicators, Korean manufacture/Oil Price indicators, Trade/Current indicators are significant for each other city. All adjusted R2 values are high enough to explain our model and the result showed excellent performance in terms of analyzing the different factors which affects air cargo volume. If companies that are currently doing business with China can identify factors affecting China's cargo volume, they can be flexible in response to changes in plans such as plans to enter China, production plans and inventory management, and marketing strategies, which can be of great help in terms of corporate operations.

For zinc-air batteries, there are several limitations associated with zinc anodes. The self-discharge behavior of zincair batteries is a critical issue that is induced by corrosion reaction and hydrogen evolution reaction (HER) of zinc anodes. Aluminum and indium are effective additives for controlling the hydrogen evolution reaction as well as the corrosion reaction. To enhance the electrochemical performances of zinc-air batteries, mechanically alloyed Zn-Al and Zn-In materials with different compositions are successfully fabricated at 500rpm and 5h milling time. Investigated materials are characterized by X-ray diffractometer (XRD), field emission scanning electron microscope (FE-SEM), and energy dispersive spectrometer (EDS). Alloys are investigated for the application as novel anodes in zinc-air batteries. Especially, the material with 3 wt% of indium (ZI3) delivers 445.37 mAh/g and 408.52 mAh/g of specific discharge capacity with 1 h and 6 h storage, respectively. Also, it shows 91.72 % capacity retention and has the lowest value of corrosion current density among attempted materials.

A zinc-air battery consists of a zinc anode, an air cathode, an electrolyte, and a separator. The active material of the positive electrode is oxygen contained in the ambient air. Therefore, zinc-air batteries have an open cell configuration. The external condition is one of the main factors for zinc-air batteries. One of the most important external conditions is temperature. To confirm the effect of temperature on the electrochemical properties of zinc-air batteries, we perform various analyses under different temperatures. Under 60 oC condition, the zinc-air cell shows an 84.98 % self-discharge rate. In addition, high corrosion rate and electrolyte evaporation rate are achieved at 60 oC. Among the cells stored at various temperature conditions, the cell stored at 50 oC delivers the highest discharge capacity; it also shows the highest self-discharge rate (65.33 %). On the other hand, the cell stored at 30 oC shows only 2.28 % self-discharge rate.

This experiment evaluated the efficiency of mechanical ventilation, one of the measures to reduce indoor radon concentration in residential spaces. In the most popular ventilation rates of the air conditioning system, the most efficient air conditioning system was confirmed by checking the time when the radon concentration reached the lowest level, the radon reduction rate, and the radon concentration that could be lowered as much as possible. The results showed a reduction rate of up to 80% or more as a result of conducting the experiment by blocking the inflow of outside air. It was confirmed that the time to reach the lowest concentration after starting the mechanical ventilation was about 6 hours to a maximum of 7 hours. Therefore, this study verified that indoor radon concentrations can be efficiently reduced by using a mechanical ventilation system.

In this study, the effect of improving indoor air quality according to the installation of plants was evaluated in classrooms where students spend much time. The purpose was to prepare sustainable and eco-friendly measures to improve the indoor air quality of school classrooms. A middle school in Bucheon was selected as an experiment subject, and IAQ monitoring equipment based on IoT was installed to monitor indoor air quality. After measuring the basic background concentration, plants and air purifiers were installed and the effects of improving indoor air quality using plants and air purifiers were evaluated based on the collected big data. As a result of evaluating the effects of indoor air quality improvement on the installation of plants and air purifiers, the reduction rates of PM10 and PM2.5 in descending order were plant- and air purifier- installed classes, air purifier-installed classes, and plant-installed classes. CO2 levels were reduced in the classrooms with only plants, and increased in two classrooms with air purifiers. The increase in CO2 concentration in the classrooms with plants and air purifiers was lower than in those with only air purifiers.

In this paper, we conducted a survey to reveal the general perception of parents toward outdoor air quality, particulate matter (PM), and indoor air quality (IAQ) at schools where their children attend. A total of 1,030 parents participated in this survey, where the age of their children ranged between 7 years to over 19 years of age. Each participant was either a member of a non-governmental organization (NGO) with a keen interest in air quality or an ordinary public panel member with less interest. The result of the survey indicated that the participants had a negative perception of air quality, and parents believed that the outdoor and indoor air is extremely polluted. The participants pointed out that they believe that the main reason for the pollution is due to particulate matter (PM) and school classrooms are the location where their children are exposed to PM the most. Based on our study, the majority of the participants prefer a mechanical ventilation system to reduce indoor air pollutants in schools. Our study should be referred to by school officials in order to maintain IAQ and as a way of addressing the concerns of parents who want to protect their children’s health.

The correlation among gaseous air pollutants (odorous compounds, greenhouse gases) and meteorological parameters was analyzed in-depth using measurement data at a barn and ambient in a naturally ventilated dairy farm. Both concentration and emission data (loading rate and emission rate), which more accurately express the actual pollutant emissions, were used in the correlation analysis. Gaseous air pollutants (ammonia, hydrogen sulfide, carbon dioxide, nitrous oxide, methane) and meteorological factors (relative humidity, temperature, wind speed, solar strength) were measured for one week in July 2013. The upper and lower outliers of measured data by inducing 1.5 times the interquartile range (IQR) were eliminated. After eliminating the outliers and grouping according to data magnitude, the correlation analysis among gaseous compounds and meteorological factors was conducted using the average values of each group. In the correlation analysis, data for the emission rate (barn) and the loading rate (ambient) showed a better correlation than concentration data. Gaseous air pollutants except for hydrogen sulfide in the barn showed a good correlation. Hydrogen sulfide might not be produced from manure or animal origin. Rather, the compound may be produced by flushing water, which was flushed at periodical times (every six hours). Ammonia emissions increased with increasing temperature, and this increase can be affected from greater exertion of feces by frequent water drinking in a high-temperature condition. In the ambient, the correlation for all gaseous air pollutants was better than that in the barn, because those air pollutants from manure, animals, and flushing water origins were sufficiently mixed in the atmosphere. Wind speed also showed a good correlation with all gaseous air pollutants.

This study examines the influence of self-identity on sustainable consumer behavior in the context of air traveling and the moderating effect of advertisement addressing these identities. Drawing on the flyers’ dilemma, the identity-based motivation theory and cognitive dissonance theory hypotheses are tested by the means of a scenario-based online experiment.

Actively promoting pro-environmental behavior not only can effectively reduce degree of environmental pollution, but also is a necessary step for the sustainable development of social economy. Although scholars have had in-depth discussions on influencing factors and promoting mechanism of pro-environmental behavior, research concerning effects of external situational factors on pro-environmental behavior is relatively insufficient, and impacts of natural environment conditions, say, air quality is seldom considered. With the development of China’s economy, industrial growth and advancing urbanization, air quality continues to deteriorate when acid rain, haze and other harsh weathers occur more frequently, seriously affecting and endangering people’s health and daily life. So, does air quality also affect people’s pro-environmental behavior? And if so, how is that impact? What is the internal mechanism? Based on the above questions, this paper designed two studies, in combination with spatial distance, and explored the impacts of air quality on Chinese residents’ pro-environmental behavior. It also demonstrated the internal impact mechanism from the perspective of environmental emotion, and expanded research on impact mechanism of air quality on pro-environmental behavior.