Mold is one of the important bio-aerosols affecting human health in the indoor environment. To manage mold contamination, it is necessary to use an appropriate method for its detection and enumeration. Recently, the impaction method of ISO 16000-18 has been established as one of methods to detect and enumerate molds in air. To investigate the general use of the impaction method for mold detection in domestic indoor environments, the suitability of the method was assessed using different antibiotics, media and air samplers. All of the three antibiotics tested - ampicillin, chloramphenicol and streptomycin - showed inhibitory effects on bacterial colony formation on MEA and DG-18 media, without inhibiting mold growth. Of these three antibiotics, ampicillin was the most effective. There was no statistical difference between MEA and DG-18 media in the measurement of mold concentration. The formation of discriminative colony morphology was more apparent in DG-18 media. No significant difference in the measurement of mold concentration was found between Andersen samplers and MAS- 100NT samplers, which are two major samplers introduced in Korea.

In this study, swine and cattle farms located in Jeollanam-do were selected to analyze and evaluate the components of odorants in livestock facilities. In addition, a preliminary survey of the literature was conducted to establish a sampling and analysis method for phenol and indoles which are major components of odor emissions from livestock facilities, yet are not regulated by the laws. To establish a sampling and analysis method for phenol and indoles, Tedlar bag and Tenax-TA sorbent tube was used as background concentration of blank sample and samples according to the elapsed time. The results obtained indicate the GC/MS analysis with Tenax-TA sorbent tube sampling was an effective method for measuring the compounds of phenol and indoles. In the swine facility, the rankings of the odorants in order, from highest to lowest, were ammonia, sulfuric compounds, phenol/indoles, volatile fatty acids. The main odorants were hydrogen sulfide (41.3%) and 4-methylphenol (p-cresol, 13.9%). In the swine slurry storage, hydrogen sulfide (33.7%), ammonia (18.8%), and 3-methylindole (skatole, 15.7%) were the main odorants, and hydrogen sulfide (31%) and i-valeric acid (32.4%) were the main odorants in the cattle farms.

This study compared the stability of odor compounds in three different types of polymer sampling bags. Tedlar, PET (polyethylene terephthalate) and aluminized polyester bag were used. A sample was collected from the interior of a new automobile which was parked in an outdoor parking lot. It was found that the Tedlar bag showed lower stability for odor active compounds than the PET bag. Meanwhile, the PET bag had good stability for odor compounds compared to the aluminized polyester bag. The PET bag showed a stability for the molecules smaller than toluene that was comparable to the canister, but showed a lower recovery for molecules bigger than C7. The FID signal of the sample in the PET bag was reduced by 1.7times after 3days storage compared to 24 h storage. The number of detected odor active compounds was reduced by half, and odor intensity was also decreased by 2~3 degrees. Considering the factors of repeated use, usability and price, a PET bag covered with a black plastic bag was the most appropriate approach for odor sampling in an automobile interior.

This paper describes the Bayesian approach for reliability demonstration test based on the sequential samples from the one-shot devices. The Bayesian approach involves the technical method about how to combine the prior distribution and the likelihood function to produce the posterior distribution. In this paper, the binomial distribution is adopted as a likelihood function for the one-shot devices. The relationship between the beta-binomial distribution and the Polya’s urn model is explained and is used to make a decision about whether to accept or reject the population of the one-shot devices by one by one then in terms of the faulty goods. A numerical example is also given.

선박용 디젤엔진 배기가스에 포함된 입자상물질(PM) 가운데서 블랙카본(BC)은 극지방의 해빙을 촉진시키고 온난화를 유발하는 원인물질로서 큰 주목을 받고 있다. 본 연구에서는 향후 예상되는 PM/BC 배출 규제에 선제적으로 대응하고, 저감기술 개발 및 실증을 위한 기초연구의 일환으로 한국해양대학교 실습선 한바다호를 이용하여 실제 운항 중에 주기관의 배기관 수 포인트에서 PM을 샘플링하여 HR-TEM을 통해 그 구조와 특성을 분석하였다. 또한 배기가스 분석기를 이용하여 운전조건별 배기가스 내 유해물질의 배출 경향을 확인하였다. 분석 결과 엔진에서 배출된 PM의 구조는 구형 입자들의 촘촘하지 않은 체인형 결합으로 이루어져 있으며, 과급기로부터 멀어질수록 온도 저하에 의한 응집이 더 많이 관찰되었고 BC 특유의 graphitic 구조를 잃어가면서 점점 amorphous 구조를 띠는 경향이 나타났다. 또한 배기가스 분석을 통해 엔진 회전수가 증가할수록 배기 내 PM의 농도는 감소할 것으로 예측되었다.

This study was conducted to investigate the influence of moisture removal using a moisture condensation tube on the odor concentration, when sampling a malodorous substance from an odor discharge facility’s emission sites. For high-temperature and humid gas streams, the odor concentration was decreased through the use of a moisture condensation tube. The multiple odor concentration of the high-temperature and humid gas streams emitted from boiler-burning equipment decreased from a 3,000 to a 1,221 dilution factor when using one or two moisture condensation tube. This multiple odor concentration was further decreased to a 1,000 dilution factor by using two moisture condensation tubes and glass beads, and also was decreased to a 374 dilution factor by using two moisture condensation tubes and silicagel. Among the designated offensive odorous substances, ammonia, trimethylamine and acetaldehyde that have high solubility in water showed high reduction rate of their concentration. Compared to the result using a sampling tube only, the concentration was decreased by 94.8% ~ 97.7% for ammonia, by 87.5% ~ 95.9% for trimethylamine and by 100% for acetaldehyde. The findings of this study indicate that sampling using a moisture condensation tube affects the concentration of multiple odors. Therefore, it is considered that using a sampling tube only for emissions sampling enhances analytical accuracy and precision rather than using moisture condensation tube with sampling tube, even for the emissions containing moisture.

This study adopts a flow theory perspective to investigate the learning engagement levels of 224 Korean high school students during EFL classes and the factors that may relate to differences in their engagement. Engagement was defined as the simultaneous experience of concentration, interest, and enjoyment. The experience sampling method was employed to measure 10th and 11th graders’ appraisals of instructional activities. Each participant was sampled twice randomly during each of three observed lessons. Momentary levels of engagement were examined in relation to students’ appraisals of activity qualities (importance for future goals, difficulty, possessed skills/competence in the area of the activity), and contextual factors (gender, grade, teacher, ability-track). Descriptive analyses, ANOVAs, and t-tests revealed that only 13% of the students were optimally engaged in lessons that were predominantly teacher-centered; increased engagement was associated with students’ appraisals of activity importance for future goals and with feelings of competence; and learner group engagement differed according to who taught them. Some teachers seemed to use an approach more conducive to engagement.

온실재배 오이에 발생하는 목화진딧물의 발생밀도를 추정하는 표본조사법을 개발하기 위하여 2개년(2013-2014년) 동안 주 전체의 잎별 발생밀도를 조사하였다. 목화진딧물의 공간분포 특성은 일반적으로 사용되는 Taylor’s power law(TPL)와 Iwao’s patchiness regression (IPR) 두 가지 방법을 이용하여 분포특성을 조사하였다. 목화진딧물의 주 전체 밀도를 대표할 수 있는 표본단위를 일정 잎 위치의 평균밀도와 주 전체의 잎당 평균밀도와의 일반선형 회귀식을 이용하여 결정하였다. 적정 표본단위는 오이 생육기에 따라 달랐는데, 총엽수가 9매 미만일 경우 2매(중위 엽과 최하위+1번째 엽), 그 이상인 경우에는 3매(위로부터 4번째, 7번째, 최하위+1번째 엽)를 조사하는 것이 적합하였다. 오이에서 목화진딧물의 공간분포 특성은 TPL과 IPR의 기울기가 모두 “1”보다 커 집중분포를 하고 있었으며, 진딧물의 평균-분산 관계를 TPL이 IPR보다 더 잘 설명하 였다. TPL의 기울기와 절편은 연차간에 차이가 없었으며, Green과 Kuno의 식을 이용하여 고정 정확도(D) 수준에서의 축차표본조사법을 개발 하였다. 목화진딧물의 축차표본조사법은 Green의 방법이 Kuno에 비해 더 효율적이었다. 목화진딧물의 일정 평균밀도를 추정하기 위해 필요한 조사 주수는 D값과 잎당 평균밀도가 낮을수록 증가하는 경향이었다. 표본조사를 중지할 수 있는 누적 진딧물 수는 D값이 낮을수록, 조사 주수가 적을수록 증가하는 경향이었다. 목화진딧물 잎당 10마리의 밀도를 추정하기 위해 필요한 조사 주수는 13주이었으며, 이 때 조사를 중지하기 위한 누적 진딧물수는 131마리이었다.

ASCE 4 requires that a hard stop be built around the seismic isolation system in nuclear power plants. In order to maintain the function of the isolation system, this hard stop is required to have clearance-to-stop, which should be no less than the 90th-percentile displacements for 150% Design Basis Earthquake (DBE) shaking. Huang et al. calculated clearance-to-stop by using a Latin Hypercube Sampling technique, without considering the rocking behavior of the isolated structure. This paper investigates the effects on estimation of clearance-to-stop due to 1) rocking behavior of the isolated structure and 2) sampling technique for considering the uncertainties of isolation system. This paper explains the simplified analysis model to consider the rocking behavior of the isolated structure, and the input earthquakes recorded at Diablo Canyon in the western United States. In order to more accurately approximate the distribution tail of the horizontal displacement in the isolated structure, a modified Latin Hypercube Sampling technique is proposed, and then this technique was applied to consider the uncertainty of the isolation system. Through the use of this technique, it was found that rocking behavior has no significant effect on horizontal displacement (and thus clearance-to-stop) of the isolated structure, and the modified Latin Hypercube Sampling technique more accurately approximates the distribution tail of the horizontal displacement than the existing Latin Hypercube Sampling technique.

The density of sweetpotato whitefly, Bemisia tabaci, on greenhouse paprika (Capsicum annuum var. angulosum) were determined by counts of the number of B. tabaci per leaflet in Jinju, Gyeungsangnamdo during 2014. Binomial sampling plans were developed based on the relationship between the mean density per leaf (m) and the proportion of leaf infested with less than T B. tabaci per leaf (PT), according to empirical model (ln(m) = α + β(ln(-ln(1-PT))). T was defined as tally threshold, and set to 1, 2, 3, 4, 5 (adults) and 1, 3, 5, 7 (pupae) per leaf in this study. Increasing sample size, regardless of tally threshold, had little effects on the precision of the binomial sampling plan. Increasing sample size had little effect on the precision of the estimated mean regardless of tally thresholds. T=1 was chosen as the best tally threshold for estimating densities of B. tabaci adults based on the precision on the model and T=3 was best tally thresholds in B. tabaci pupae. Using the results obtained in the greenhouse, simulated validation of the developed sampling plan by RVSP (Resampling Validation for Sampling Plan) indicated the suitable results.

파프리카(Capsicum annuum var. angulosum)의 주요해충인 담배가루이(Bemisia tabaci)의 고정 정확도 수준에서 표본조사법(Fixedprecision sampling plan)을 개발하였다. 개발된 표본 조사법은 파프리카 온실의 담배가루이 방제체계 확립을 위해 공간분포분석, 표본추출 정시선 그리고 의사결정법으로 이루어 졌다. 자료 수집은 식물체를 상단(지상으로부터 180-220 cm), 중단(지상으로부터 80-120 cm), 하단(지상으로부터 30-70 cm)로 나누어 각 위치별 3개의 파프리카 잎에서 담배가루이 성충, 번데기를 관찰하고 그 총 수를 기록하였다. 담배가루이 성충은 식물체의 상부에서 움직이고 신초에 주로 산란하며 일정부분이 하단으로 내려오기 때문에 상단과 하단에 많이 분포하였으며, 번데기의 경우 상부에 알을 낳았지만 식물체가 크면서 알을 낳은 잎이 아랫부분이 되고 부화한 유충은 잎 뒤에 고착 상태로 우화까지 움직임이 거의 없기 때문에 중단과 하단에서 많이 분포하였다. 공간분포분석은 Taylor’s power law (TPL)를 이용하였으며, TPL계수의 차이를 공분산분석(ANCOVA)하여 차이가 없는 경우 자료를 통합하여 계산된 새 TPL 상수값을 이용하여 표본추출 정시선을 구하였다. 그리고 담배가루이 성충과 번데기의 방제밀도수준을 2.0마리와 10.0마리로 설정하여 방제의사를 결정하였다. 마지막으로 분석에 사용하지 않은 독립된 자료를 이용하여 개발된 표본추출법의 유효성을 Resampling Validation for Sampling Plan (RVSP) 프로그램으로 평가한 결과 적합한 정확도를 보였다.

고병원성조류인플루엔자(Highly Pathogenic Avian Influenza, HPAI)는 폐사율이 100%에 이르는 급성 조류 바이러스성 전염병이다. 우리나라는 2003년 첫 발생 이후 5회에 걸친 대규모 유행으로 인하여 막대한 경제적 손실을 경험한 바 있어 HPAI 발생을 가능한 조기에 검출하고 신속하게 대응함으로써 피해를 최소화하기 위한 국가적 모니터링 사업을 지속적으로 추진해오고 있다. 특히 국내의 경우 HPAI는 철새의 이동경로를 통하여 바이러스가 유입된 것으로 추정되고 있어 방역당국에서는 철새 이동에 따른 바이러스 조기검출을 위하여 주요 철새 도래지를 중심으로 무작위 방식의 철새의 분변시료 채취 사업을 진행하고 있다. 시료채취 방법과 관련하여 표본추출 지점들이 인접할수록 공간적 자기상관성(spatial autocorrelation)으로 인하여 표본들이 비슷 한 정보를 가질 수 있기 때문에 표본으로서의 철새 도래지 추출과정에서 이를 반영할 필요가 있다. 본 연구의 목적은 지리적으로 인접한 철새 도래지들이 유사한 표본정보를 가질 수 있음을 전제로 공간적 자기상관성을 고려한 공간표집방법론을 구축하고 실증적 활용성을 가늠해보는 것이다. 이를 위하여 전국 196개 조류 도래지들을 대상으로 분석결과를 도출하고 해석적 함의를 논의하였다.

A fixed-precision level sampling plan was developed for Bemisia tabaci in paprika greenhouses. A sampling plan consisted spatial distribution analysis, sampling stop line and decision making in order to establish B. tabaci control in paprika greenhouses. Sampling was conducted in two independent greenhouses at same time (GH 1, GH 2). The GH 1 and 2 were surveyed every week for 22 consecutive weeks, sampling locations of each greenhouse were 19 for GH 1, 9 for GH 2, respectively. The plants in the both greenhouse were divided top (200cm from the ground), middle (100cm from the ground), bottom (50cm from the ground) and observed B.tabaci’s adults and B.tabaci’s pupae in three paprika leaves at each position and recorded separately. GH 2 data was used to validate of fixed-precision sampling plan which developed by GH 1 data. In this study, spatial distribution analysis was evaluated using Taylor’s power law with the pooled data of the top and bottom (B.tabaci’s adults), the middle and bottom (B.tabaci’s pupae) in a 1-leaf sampling unit. Decision making is evaluated by maximum & minimum of action threshold according to the condition from several reference, and the value decided by the price of the plants. Using the results obtained in greenhouse, result simulated validation of developed sampling plan by RVSP(Resampling Validation for Sampling Plan) was showed reasonable precision level.

In this research we investigate motion controller performance for mobile robots according to changes in the control loop sampling time. As a result, we suggest a proper range of the sample time, which can minimize final posture errors while improving tracking capability of the controller. For controller implementation into real mobile robots, we use a smooth and continuous motion controller, which can respect robot’s path curvature limitation. We examine motion control performance in experimental tests while changing the control loop sampling time. Toward this goal, we compare and analyze experimental results using two different mobile robot platforms; one with real-time control and powerful hardware capability and the other with non-real-time control and limited hardware capability.

담배가루이, Bemisia tabaci는 바이러스병의 매개로 인해 제주지역 시설재배 토마토에서 가장 중요한 해충으로 인식되고 있다. 황색끈끈이 트랩을 이용한 담배가루이 성충의 실용적인 발생밀도 추정방법을 개발하기 위하여 2011과 2012년 제주 서부지역의 농가재배 토마토 포장에서 포장 상황에 따라 20～30개의 트랩을 설치하여 7～10일 간격으로 조사하였다. 황색끈끈이트랩을 지상 60 cm 높이에 수평방향으로 설치한 것 이 작물 상단 10 cm 위에 수직으로 설치한 것보다 더 많은 담배가루이가 유인되었다. 황색끈끈이트랩에 유인된 담배가루이 성충의 분포형태를 Taylor’s power law (TPL)과 Iwao’s patchiness regression (IPR)을 이용 분석한 결과 두 회귀식의 기울기값이 모두 “1”보다 커 담배가루이 성충이 집중분포를 하고 있었다. TPL의 결정계수(r 2 )값이 IPR보다 더 높아 TPL이 담배가루이 성충의 공간분포 특성을 더 잘 설명하고 있었다. 담배가루이 성충 밀도를 추정하는데 필요한 황색끈끈이트랩의 수를 TPL 상수를 이용하여 추정하였는데 정확도 수준이 높을수록, 평균밀도가 낮 을수록 필요한 트랩수는 증가하는 경향이었다. TPL 상수를 이용하여 고정 정확도 수준에서 조사를 중지하더라도 트랩당 평균밀도를 추정이 가 능한 누적밀도를 계산하였다. 담배가루이 성충의 방제시기를 트랩 최고 밀도 10마리로 가정했을 때 이 밀도에서 필요한 포장당 트랩수는 고정정 확도 0.25수준에서 15개이었다. 담배가루이 성충의 트랩당 평균밀도는 트랩마다 모든 성충수를 계수하는 것보다 2마리 이상 유인된 트랩의 비율 을 가지고 추정하는 이항모델 [ln(m) = 1.19 + 0.90 ln(-ln(1-pT))]을 이용하는 것이 더 효율적이었다. 본 연구결과는 담배가루이 성충에 대한 정 확한 방제의사 결정을 통해 담배가루이가 매개하는 바이러스병 확산을 막는데 일조할 것으로 기대된다.