• Korean Journal of Environmental Agriculture
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• v.1 no.2
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• pp.105-115
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• 1982

Environmental samples contaminated with elemental sulfur(waters 22, sediments 20, crucian carps 19) collected from Soho Lake during the period of Sep. 1981 to Apr. 1982 were analyzed for polychlorinated biphenyls(PCBs) and organochlorine insecticides by GLC-ECD. Elemental sulfur was found to interfere in the residue analysis of environmental samples and the sulfur was eliminated, prior to analysis, with copper powder. PCBs residues in Soho lake were temporarily characterized as Aroclor 1254 and were analyzed at minimum detectable quantity of 0.04 ng by derivatizing PCBs to decachlorobiphenyl(DCB). PCBs were positively detected in all samples and its residue levels in waters, sediments, and crucian carps were $0.015{\sim}0.15$ ppb, $0.038{\sim}0.088$ ppm and 0.091 ppm, respectively. The residue levels of PCBs in all samples but sediments at central and outlet site of the lake were higher than those of total p,p'-DDT. The residue levels of PCBs in waters varied with inlets, i.e. those at right inlet site were three times of those at left inlet site. The main source of PCBs residues in the environmental samples of Soho Lake was not evident by present work.

• The Korean Journal of Pesticide Science
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• v.19 no.4
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• pp.361-369
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• 2015

This study investigated residual characteristics of bistrifluron and fluopicolide in Korean cabbage, and suggested the pre-harvest residue limits (PHRLs) based on their dissipation patterns and biological half-lives. The pesticides were sprayed on Korean cabbage in two different region under greenhouse conditions at the recommended dose, respectively. The samples for residue analysis were harvested at 0 (2 hr), 1, 2, 4, 6, 8 and 10 days after treatment, and analyzed by HPLC after clean-up with Florisil SPE. The limit of quantification (LOQ) was $0.03mg\;kg^{-1}$ for bistrifluron and fluopicolide, and the recoveries ranged from 87.2-110.6% with below 5% of RSD. The biological half-lives of field I and field II were 3.9 and 4.2 days for bistrifluron and 4.9 and 4.2 days for fluopicolide, respectively. The PHRL of bistrifluron and fluopicolide were recommended as 3.83 and $3.23mg\;kg^{-1}$ for 10 days before harvest, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.137-143
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• 2020

To ensure safety of raw materials for military foods, hazard assessment and monitoring of residual pesticides was conducted on agricultural products consumed by 9 companies based in Gyeongin and Gangwon. Residual pesticides were analyzed for 142 different products, by applying the multi-species pesticide polycomponent analysis method. Of the 36 samples analyzed, residual pesticides were detected in 7 samples, representing a detection rate of 19.4%. One particular pesticide residue was detected in peanuts, green onions, and red pepper powder, and 20 types of pesticide residues were detected in red pepper powder used in combat foods. However, all residues were found to be below the permissible level. Moreover, the hazard assessment results for Cypermethrin, Tebuconazole and EPN showed the highest concentration among the residual pesticides detected. Since the estimated intake was less than 100% as compared to the ingestion limit, it was considered to be safe. I have suggested the edit as per my understanding. Please review for accuracy, and revise appropriately if required. This is the first pesticide Risk Assessment study encompassing military requirements. Considering the results, we expect further application research, including research on reducing hazardous materials.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.4
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• pp.1-17
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• 2022

As pedestrian deaths account for a high proportion of traffic accident deaths in Korea, interest in pedestrian safety is growing. In particular, it is necessary to develop various pedestrian-centered traffic signal operation techniques to improve the pedestrian environment at signal intersections. Therefore, in this study, a method for time-of-day operating a pedestrian signal based on residual pedestrians was studied. To this end, the pedestrian signal operation technique in response to the pedestrian demand, which is operated by extending the pedestrian signal time only during the time when the pedestrian demand and the number of remaining pedestrians increase, was applied to the field. The difference in safety according to the application of the new pedestrian signal operation technique was statistically analyzed. As a result of the analysis, the residual pedestrian rate decreased by 20% (3.3 people) before application and 8% (1.4 people) after application, and the residual pedestrian rate in the crosswalk at the time of red signal decreased by 12% (1.9 people), And it was analyzed that the position of the residual pedestrian decreased by 3.3m from 5.2m before application to 1.9m after application.

• Journal of Korea Water Resources Association
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• v.56 no.11
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• pp.705-720
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• 2023

In South Korea, ongoing incidents related to drinking water quality have eroded consumer trust. Specifically, beyond quality incidents, there have been complaints about taste, odor, and other issues stemming from the presence of chlorine. To address this, water service operators are employing various management strategies from both temporal (scheduling) and spatial (rechlorination) perspectives to ensure uniform and safe distribution of chlorine residuals. In this study, we focus on the optimal monthly management of chlorine residuals, based on water distribution network analysis. Water quality reaction coefficients, including bulk fluid and wall reaction coefficients, were estimated through lab-scale tests and EPANET water quality simulations, respectively, accounting for temperature variations in a large-scale water distribution network. Utilizing these estimated coefficients, we examined the monthly variations in chlorine residual distribution under different chlorine injection conditions. The results indicate that the efficient concentration for chlorine injection, which satisfies the residual chlorine limit range, varies with temperature changes. Consequently, it is imperative to establish a specific and quantitative chlorine injection plan that considers the accurate spatial distribution of monthly chlorine residuals.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06e
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• pp.411-414
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• 1998

음성의 음질 향상(Speech Enhancement)을 위한 여러 가지 방법 중에서 주파수 차감법(Spectral Subtraction)은 계산량이 적기 때문에 현재 실시간으로 Speech Enhancement를 할 수 있는 가장 적절한 방법이다. 그러나, 이 방법은 원래의 입력음성에 없던 새로운 잡음을 만들어내는 큰 단점이 있는데, 이를 제거하기 위해 많은 연구가 되어오고 있다. 이러한 연구의 방향은 대부분 주변프레임 또는 주변의 주파수 성분과의 평균을 통해 피크값을 무디게 해 줌으로써 새로 생긴 튀는 잡음을 감소시키는 것이다. 이런 방법은 음성자체의 정보 또한 평균이 되어버리게 하는 새로운 단점을 낳는데, 이런 현상은 무성음구간에서 특히 심각해진다. 본 논문에서는 입력음성의 LPC 분석으로 백색필터(Whitening Filter)를 구성하여 이를 통과시킨 잔류신호(Residual)를 주파수 차감하여 얻은 새로운 잔류신호를 역 필터링하여(Synthesis Filter) 개선된 음성을 얻는 방법을 제안하였다. 제안된 알고리듬은, 주파수 차감시 포만트(Formant)의 정보가 더 유지 될 수 있기 때문에 잔류잡음을 줄일 수 있다. 청취 테스트 결과 제안한 방법이 기존의 방법보다 잔류잡음을 더 줄이는 사실을 확인할 수 있었다.

• The Korean Journal of Pesticide Science
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• v.20 no.4
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• pp.341-348
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• 2016

Residual patterns of fungicides fludioxonil and metconazole applied 2 or 3 times on wheat were investigated with consideration for their distribution rates in each compartment of wheat. Wheat samples collected at harvesting day were divided into three compartments such as grain, hull and straw, and the pesticide residue analysis was individually carried out to such compartments of wheat. The analytical methods of fungicide residues in wheat were acceptable, with recoveries of 84.3 to 113.3% and correlation coefficients of 0.1 to 4.7%. Due to the systemic characteristics, the residual amounts of metconazole in the grain part of wheat were greater as 0.13~0.17 mg/kg than those amounts (0.01-0.03 mg/kg) for fludioxonil. To absolute residue amounts of the fungicides in one wheat plant, their distribution rates in each compartment of wheat were the highest in straws (68.5-70.7%), followed by hulls (29.0-31.0%) and grains (0.2-0.8%).

• Korean Journal of Environmental Agriculture
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• v.14 no.1
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• pp.23-27
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• 1995

The cross-reactivities of antibody derived from rabbit immunized with metalaxyl-HSA conjugate were identified to 44% and 28% for metalaxyl acid and metolachlor respectively. The detection range of metalaxyl in competitive ELISA was 5 ppb to 5 ppm. The recoveries of metalaxyl in ELISA for 6 crops; potato, sesame, pepper, cabbage, cucumber and onion was ranged 77.5-103.6%. In this test, CV% were calculated below 10% except for sesame sample as shown 21.5%.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.4
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• pp.95-100
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• 2019

Nanoindentation has been widely used for evaluating mechanical properties of nano-devices, from MEMS to packaging modules. Residual stress is also estimated from indentation tests, especially the Knoop indenter which is used for the determination of residual stress directionality. According to previous researches, the ratio of the two stress conversion factors of Knoop indentation is a constant at approximately 0.34. However, the ratio is supported by insufficient quantitative analyses, and only a few experimental results with indentation depth variation. Hence, a barrier for in-field application exists. In this research, the ratio of two conversion factors with variation in indentation depth using finite elements method has been attempted at. The magnitudes of each conversion factors were computed at uniaxial stress state from the modelled theoretical Knoop indenter and specimen. A model to estimate two stress conversion factor of the long and short axis of Knoop indenter at various indentation depths is proposed and analyzed.

• Journal of Food Hygiene and Safety
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• v.34 no.2
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• pp.115-123
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• 2019

An analytical method was developed for the determination of fenpropimorph, a morpholine fungicide, in hulled rice, potato, soybean, mandarin and green pepper using QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) sample preparation and LC-MS/MS (liquid chromatography-tandem mass spectrometry). The QuEChERS extraction was performed with acetonitrile followed by addition of anhydrous magnesium sulfate and sodium chloride. After centrifugation, d-SPE (dispersive solid phase extraction) cleanup was conducted using anhydrous magnesium sulfate, primary secondary amine sorbents and graphitized carbon black. The matrix-matched calibration curves were constructed using seven concentration levels, from 0.0025 to 0.25 mg/kg, and their correlation coefficient ($R^2$) of five agricultural products were higher than 0.9899. The limits of detection (LOD) and quantification (LOQ) were 0.001 and 0.0025 mg/kg, respectively, and the limits of quantification for the analytical method were 0.01 mg/kg. Average recoveries spiked at three levels (LOQ, $LOQ{\times}10$, $LOQ{\times}50$, n=5) and were in the range of 90.9~110.5% with associated relative standard deviation values less than 5.7%. As a result of the inter-laboratory validation, the average recoveries between the two laboratories were 88.6~101.4% and the coefficient of variation was also below 15%. All optimized results were satisfied the criteria ranges requested in the Codex guidelines and Food Safety Evaluation Department guidelines. This study could serve as a reference for safety management relative to fenpropimorph residues in imported and domestic agricultural products.