• 생물환경조절학회지
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• 제8권4호
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• pp.281-287
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• 1999

현장조사 결과 패드-팬 시스템의 경우 6개 농가 모두 사용하고 있었으며, 온실 내기온은 외부기온보다 2~5$^{\circ}C$ 낮았다. 이시스템의 냉방효율은 평균 77.4% 이었으며, 외부의 상대습도가 60%이하 일 경우 냉방 효율이 높았다. 포그 시스템의 경우 현장조사에서 9농가 중 6농가가 사용을 못할 정도로 많은 문제점이 발견되었다. 포그입경, 분무수량, 운영 방법등 개선해야 할 사항이 많았다. 실험온실의 경우도 노즐의 설치 위치와 제어방법에서 문제점이 발견되었다. 포그입자가 커 증발하지 못하고 대부분이 바닥과 차광망으로 낙하하였고, 지역 기상조건을 고려하지 못한 제어방법으로 냉방효과를 떨어뜨리고 있었다. 냉방효과를 높이가 위하여 노즐의 위치 선정, 제어방법에 대한 연구가 수행되어야 하며, 지역적 기상특성을 고려한 연구와 내부 습도를 낮게 유지하는 연구도 수행되어야 할 것이다.

• 한국농공학회지
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• 제17권2호
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• pp.3763-3771
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• 1975

This study was attempted to investigate the changes of specific fuel consumption, compression pressure and power output, consequently to obtain basic data on farm kerosene engine. The samples which are used in this study are a 4 cycle water cooled korosene engine for the use of K6-CT83 power tiller and a 4 cycle air-cooled kerosene engine for the use of G5L-3A water pump. The Korean Industrial Standards (K.S)KS-B 6002 "Test code of small internal combustion engine" was referred in carrying out this study, and its results are as follows. 1. According to load increasing, the speific fuel consumption of the engines generally decreases, however, in case of 10% over-loading it increases. 2. As a result of full load consecutive operation, according to passing of operating time, the amount of wear generally increases, consequently the speific fuel consumption also increases, and inversly the compression pressure decreases. 3. The changes of specific fuel consumption and compression pressure were closely related with time of piston ring exchange, and periodically about 100 hours the engines show the increase of specific fuel consumption and the decrease of compression pressure. 4. After about 300 hours, although the engine had new piston rings, the specific fuel consumption increase, consequently the engine needs boring. In actual use, it is impossible to operate consecutively on full load, therefore the boring time of engine is expected to come later.

• 인터넷정보학회논문지
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• 제22권6호
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• pp.17-24
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• 2021

The use of renewable energy sources for power generation has been steadily increasing. Power generation using renewable energy has the advantage of not generating carbon but has the disadvantage of high volatility depending on the weather. This volatility makes stable power supply difficult. Curtailment is occurring to address volatility. Various facilities are operated together to solve the loss caused by the curtailment. The existing SCADA must be modified for turbine control reflecting the conditions of various facilities. However, since it is difficult to modify SCADA, a modular control system is required. In this study, we propose Modular Control System Based on Closed-Loop Control for Wind Farms. Since the control logic can be changed without modifying SCADA, it is easy to respond to changes. The developed modular control system was evaluated as a lab test and confirmed to operate smoothly. Through future research, the experiment will be conducted by applying a modular control system to the actual wind farm.

• 한국임상수의학회지
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• 제30권4호
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• pp.258-263
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• 2013

The primary goal of this study was to compute sample sizes required to achieve the each aim of a variety of foot-and-mouth disease (FMD) surveillance programs, using a statistically valid technique that takes the following factors into account: sensitivity (Se) and specificity (Sp) of diagnostic test system, desired minimum detectable prevalence, precision, population size, and desired power of the survey. In addition, sample sizes to detect FMD if the disease is present and also as proof of freedom were computed. The current FMD active surveillance programs consist of clinical, virological, and serological surveillance. For the 2012 serological surveillance, annual sample sizes (n = 265,065) are planned at four separate levels: statistical (n = 60,884) and targeted (n = 115,232) at breeding pig farms and slaughter house, in together with the detection of structural proteins (SP) antibodies against FMD (n = 88,949). Overall, the sample size was not designed taking the specific aims of each surveillance stream into account. The sample sizes for statistical surveillance, assuming stratified two-stage sampling technique, was based to detect at least one FMD-infected case in the general population. The resulting sample size can be used to obtain evidence of freedom from FMD infection, not for detecting animals that have antibodies against FMD virus non-structural proteins (NSP). Additionally, sample sizes for targeted surveillance were not aimed for the population at risk, and also without consideration of statistical point of view. To at least the author's knowledge, sampling plan for targeted, breeding pig farms and slaughter house is not necessary and need to be included in the part of statistical surveillance. Assuming design prevalence of 10% in an infinite population, a total of 29 animals are required to detect at least one positive with probability of 95%, using perfect diagnostic test system (Se = Sp = 100%). A total of 57,211 animals needed to be sampled to give 95% confidence of estimating SP prevalence of 80% at the individual animal-level with a precision of ${\pm}5%$, assuming 800 herds with an average 200 heads per farm, within-farm variance of 0.2, between-farm variance of 0.05, cost ratio of 100:1 of farm against animals. Furthermore, 779,736 animals were required to demonstrate FMD freedom, and the sample size can further be reduced depending on the parameters assumed.

• 생물환경조절학회지
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• 제30권1호
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• pp.19-26
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• 2021

본 연구에서는 같은 지역에 위치한 온실 3곳의 식별을 위해 통계적인 방법으로 분류를 하고자 주성분 분석(PCA)과 선형 판별 분석(LDA)을 수행하였다. 온실 내의 환경데이터는 같은 지역의 온실 3곳을 대상으로 4월1일부터 4월28일 총4주간 1시간 간격으로 수집된 값을 사용하였다. 데이터를 분석하기 전, 데이터 정규화를 시키는 전처리를 거쳤으며, 전체의 80%인 훈련자료(training data)와 20%인 테스트 자료(test data)로 나누어 분석을 수행하였다. 분석을 수행한 결과, PC1은 57.51%의 설명력으로 PC1 = 0.7118112 × Tem. -0.6830065 × Humi. -0.1637892 × CO2.의 식을 가지며, LD1은 67.06%의 설명력으로 LD1 = 0.8622565 × Tem. -0.1805741 × Humi. + 1.4018140 × CO2. + 0.03040701의 식을 가지는 것으로 나타났다. 이렇게 미리 분류시켜놓은 온실의 데이터를 바탕으로 새로운 환경의 데이터를 입력하였을 때 특정 그룹으로의 분류가 가능함으로써 데이터의 성향을 파악할 수 있다. 이러한 데이터는 식별을 용이하게 함으로써 데이터의 활용도를 높여주는 방법이라고 판단된다.

• 대한의생명과학회지
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• 제22권4호
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• pp.199-206
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• 2016

Pesticides are widely used to prevent loss of agricultural production but extensive exposure can induce health problems to pesticide operators. This study was performed to evaluate the health risk of highly produced pesticides used in fruit growing farm land by comparison of estimated exposure level with AOEL using KO-POEM program. AOEL was driven based on NOAEL of each pesticide evaluated by JMPR, EFSA or KRDA. In calculation of exposure level, types of formulation, dilution factors, spraying duration and motor type and exposure protection device were allocated according to actual condition of use. Dermal absorption rate was differently applied among EFSA default values (25% or 75%), general default value (10%) or real test result values to know the plausibility of default values and safety of pesticide to operators in outline. Twenty pesticide ingredients (fungicides and insecticides) were produced more than 30 tons per year, which were mancozeb, chlorothalonil, imidaclopirid and etc in order. Dermal absorption rates obtained from studies were various from 0.07 to 81% but mostly under 10%. The estimated exposure levels showed big differences more than 10 times higher when using EFSA default rate and up to 5 times higher when using general rate of 10% comparing using rates of test results. Mancozeb, chlorthalonil, diazinon and chlorpyrifos presented still higher exposure level than AOEL even when using test absorption rate from study, which suggests that re-evaluation of AOEL or dermal exposure absorption rate or strict management are required for health protection of operators who use those four pesticides in farm land.

• Journal of Biosystems Engineering
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• 제29권1호
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• pp.1-8
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• 2004

In order to solve the shortage of roughage supply for dairy farm in Korea, winter cereal forage production after harvesting of rice in the fallow paddy field was studied. Two parts are already reported at the previous paper - One was the model development of the mechanized production, and the other was the study of feasibility of the model and its desirable direction in Korea. In this study, the model system is applied for a winter cereal wrap silage production model to practice in Kyungbook National University farm on 3ha scale for 3 years. Results of the research are summarized as follows; It takes 2 or 3 working days to process the wrap silage in middle of May in Daegu region. Also, not much particular problem can be found during the application test of mechanized wrap silage production. Field capacity and field efficiency are estimated to be 0.6-0.85㏊/h and 50-70% in mowing, 1.1∼1.7㏊/h and 52∼80% in tedding and raking, 0.6∼1.1㏊/h and 25∼45％ in baling and 0.5∼0.57㏊/h and 75∼85% in wraping, respectively. Total production cost is estimated to be 1,257won/kg-TDN in oversowing and wrap-silage harvest in 1.6㏊ working area. As a result, large scale field is recommended to produce the wrap silage in order to maximize the field capacity.

• 농촌의학ㆍ지역보건
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• 제10권1호
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• pp.5-15
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• 1985

It has been a long tradition in the field of nutrition that the degree of malnutrition in a community used to be estimated by the degree of the adequacy of nutrients consumption in the households. The adequacy of nutrient consumption in the households then used to be applied to estimate the degree of malnutrition of the children. Such a practice is theoretically acceptable in the community where the food sharing within the household is individual serving style such as in European countries. However, the community where the dietary habit in the household is communal such as in Korea, the estimation of single serving portion from household consumption is quite uncertain. Because of such an uncertainty this study is intended to test the validity of the household food consumption level as an indication of nutritional status of the children in the rural farm households in Korea. The date from the household consumption survey in 1982 by the Korean Rural Nutrition Institute has been used for the analysis of food consumption levels of the households. The survey on the nutritional status of children of 127 preschool children from 78 farm households, has been conducted during May 1983. The nutritional status of the children has been directly measured by weight, height, skinfold thickness, haemoglobin, haematocrit and morbidity of influenza and diarrhoea. The analysis has been conducted to distinguish the differences in prevalence of malnutrition of children from the estimated of household consumption and that of from the direct measurement of nutritional status of children. The results show that the degree of malnutrition of the estimated by the household consumption level has not related with the prevalence of malnutrition by the direct measures of nutritional status of the children. Therefore, the validity of household consumption level as an indication of nutrional status in a same household is quite uncertain for the population studied.

• 해양환경안전학회지
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• 제10권1호
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• pp.51-54
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• 2004

최근 양어 양식장은 증가하고 있으며 이러한 곳에 사용할 가열장치는 경울 수온 조절을 위해 사용된다. 해수 가열장치는 부식성이 높고 압력이 높은 곳에 사용하기 위하여 고강도와 내식성이 요구된다. 만약 저강도와 저내식성을 갖게 되면 결국 누설 또는 파손되어 해수오염을 일으킬 수 있다. 대부분의 부식은 정체된 액과 틈이 형성된 부위에서 부식의 발생이 일어난다. 이 연구에서는 430 스테인레스재를 크기 $15{\times}20{\times}3mmt$에 대하여 1N H2SO4 + 0.05N NaCl용액을 사용하여 틈부식을 시험하였다. 틈의 크기는 $0.24{\times}3{\times}15mmL$로 하였으며 외부에 300mV전위를 인가하였다. 실험 결과 틈 부식 유기 시간은 750초로 나타나고, 틈 전위 강화는 -320에서 -399mV로 나타나 부식의 주 원인이 전위강화 기구에 의해 발생하였다.

• 대한수의학회지
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• 제30권3호
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• pp.333-341
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• 1990

To investigate bovine leukosis virus (BLV) infection in the cattle rearing in a dairy farm where a case of bovine lymphosarcoma had been identified several years ago, the 196 Holstein cattle including newborn calves to 12 years of age were tested. The BLV antibody test and peripheral lymphocyte count for bovine leukosis were carried out by the immunodiffusion (ID) test and Bendixen's Kep. These tests were performed 2 to 4 times at the interval of 3 to 5 months. The observed results were as follows: 1. The positive rates of BLV-antibody in the 1st, the 2nd, the 3rd and the 4th tests were 23.3%, 28.1%, 49.0% and 55.7%, respectively. The conversion rates from negative to positive in the 2nd, the 3rd and the 4th tests were 8.9%, 41.4%, and 20.0%, respectively. Results showed that the highest conversion rate was observed at the 3rd test which was conducted after winter. The highest positive rate by ID test were observed in 4 year old cattle in the 1st and 2nd tests, and in 2 year old herd in the 3rd and 4th tests. 2. In hematological test by Bendixen's Key, the positive and suspicious rates in the 1st, the 2nd, the 3rd and the 4th tests were 5.8 and 7.8%, 8.3 and 6.6%, 8.7 and 10.1%, 10.8 and 19.6% respectively. Results showed that the positive and. suspicious rates increased in course of time. 3. 70 to 100% of the positive cattle in hematological test were positive for BLV-antibody test. All of 13 cattle with persistent lymphocytosis (PL) were also positive for BLV-antibody, indicating the high relationship between PL and BLV-antibody. 4. The number of total leukocytes and absolute lymphocytes in the BLV-antibody positive cattle appeared significantly higher than those of the negative cattle. The markedly increased cell counts were observed in the cattle over one year old. 5. The mean of total leukocytes and absolute lymphocytes in the negative cattle for BLV-antibody increased slightly after sero-conversion into positive. 6. In the clinical examinations during experimental periods, none of the 72 positive cattle for BLV-antibody showed any lesions for bovine leukosis.