• 한국물환경학회지
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• 제32권6호
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• pp.628-648
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• 2016

Increased attention has been paid to the presence of veterinary antibiotics in various environmental matrices due to their toxicological behavior in the ecosystem and development of antibiotic-resistant strains of pathogenic bacteria. In the this review, 37 target antimicrobials were selected based on annual sales of antibiotics for livestock in South Korea 2014. Also, extraction and clean-up methods for the determination of the antibiotic residues in liquid samples including water, milk, and honey were comprehensively reviewed in the literature. Solid-phase extraction (SPE) was commonly used as a pre-treatment method for the samples. Most of the analytes were extracted in acidic conditions (2.5~4.0) except for aminoglycosides, which were extracted in neutral conditions (7.0~8.0). ${\beta}-Lactams$ showed the highest recoveries in neutral pH due to their degradation characteristics in acidic media. Starta-X, Oasis HLB, and Oasis MCX were frequently applied as an SPE cartridge and Oasis HLB showed the highest recoveries for the majority of antibiotic classes. The homogenized honey and milk were extracted by mixing with acids for deproteinization. Solids and other interfering substances in the extract were eliminated by centrifugation followed by membrane filtration or SPE before injection into HPLC.

• 한국물환경학회지
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• 제32권6호
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• pp.649-669
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• 2016

This study explored the analytical conditions for 21 veterinary antibiotics which have been popularly sold in South Korea in 2014 but have not yet been targeted in EPA method 1694. Most of the selected antibiotics were separated by a reverse-phase C18 column with a combination of (buffered) water and organic polar solvent, which was commonly methanol and acetonitrile in the gradient elution mode. Volatile additives such as formic acid, ammonium acetate and ammonium formate were usually added to the mobile phases to minimize asymmetrical and tailing of antibiotics' peaks and to increase their ionization in mass spectrometry. The analytical methods of aminoglycoside antibiotics were distinct from those of the other antibiotics in terms of adoption of ion-pair chromatography (IPC) and hydrophilic interaction liquid chromatography (HILIC) capable of retaining and separating extremely polar compounds due to their hydrophilicity. Trifluoroacetic acid or heptafluorobutyric acid was frequently added to the mobile phase as an ion-pair reagent for the IPC. Tandem mass spectrometry was numerously applied to the detection of antibiotics using positive electrospray ionization (ESI) and the selected reaction monitoring (SRM) mode. All reviewed analytical methods had been/were validated by evaluating recovery, limits of detection and quantification, decision limit or detection capability of the methods.

• 한국물환경학회지
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• 제33권6호
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• pp.769-779
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• 2017

Nutrient (i.e., nitrogen and phosphorus) budgets are required under a 'Livestock Excreta Survey'. A nutrient budget is one of the agri-environmental indicators that calculates the difference between the inputs and outputs of the amount of nutrients within a certain boundary and for a certain time period (e.g., 1 year). In this study, a nutrients budget model was developed to effectively determine the surplus of nutrients within a region in Korea. The C# program language was used in order to facilitate the deployment of a graphical user interface (GUI) and to enhance compatibility. Also, the model was developed on Windows OS, which is the commonly used operating system in Korea. The model was based on the OECD/Eurostat nutrient budget method, and it was modified to consider manure composting procedures as well. There are key features of the nutrient budget model, including directly use of the original data sets from various input and output sources, and a collectively exchange of the address in different formats. The model can quickly show the results of various spatial and temporal resolutions with the same data, as well as perform a sensitivity analysis with coefficients and easily compareresults using tables and graphs. Further, it would be necessary to study the extension of the scope of utilization, such as the application of various nutrient budget methods. It would also be helpful to investigate both pre and postprocessing information such as linking input data through online systems.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2283-2286
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• 2003

This paper presents conservation of electrical energy in building with harmonics analysis and compensation which occur in electrical system. We use load controlling and management system in order to adjust load factor of system.The maximum demand limiting and controlling are used ,then the system can acquire the prediction and compare it to the maximum demand set point.The electrical signal analysis based on FFT technique. The harmonics are compensated by using harmonic filters.This system consists computer which works as controller, processor , analysis and database unit together with digital power meter in form of multidrop network through serial communication via RS-485.The load control system uses PLC to control load via serial communication RS-485. The A/D converter is used for sampling the electrical signals via parallel port of computer.The harmonic filters are controlled by a computer.The data of measurement such as voltage, current, power, power factor, total harmonic distortion, energy, etc., can be saved as database and analysis. The load factor is adjusted by limiting and controlling maximum demand. The load factor adjustment can reduce the cost of electric consumption and energy generation together with harmonics compensation in order to increase high efficiency of electrical system.

• 조명전기설비학회논문지
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• 제30권1호
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• pp.96-101
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• 2016

In this paper, We investigate the number of 795 transformer in the private electrical facilities and analyze the annual load factor. The results show that the annual load factor of transformer is 20.16% in manufacturing industry, education services(school) is 9.59%, retail and wholesale services is 19.68%, resort and leisure industry is 10.93%, office building is 13.10%, and apartment houses is 14.69%. Education services, resort and leisure industry are being operated with a very low annual load factor. The relatively small capacity of less than 500kVA transformer also been analyzed that is being operated with a low load factor. Therefore, In order to minimize the power loss of the transformer, it is advisable to complement the Transformer Efficiency Management system to be designed the efficiency is good transformer when the load is low. Analysis results will be used as the basis for the provision of transformer efficiency management system and be used High-efficiency transformers promotion system.

• 제어로봇시스템학회논문지
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• 제22권12호
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• pp.991-994
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• 2016

This paper presents a load management method based on OpenADR of smart grid. Previous demand side algorithm is restricted on reducing peak power. But, in this paper we suggest a method of performing the energy-saving control according to the power price utilizing building automatic control system installed on the customer side in the case of hourly differential pricing signal is transmitted to the open automated demand response system. And, we showed the integrated demand management software for 3 buildings.

• 한국물환경학회지
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• 제27권3호
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• pp.293-299
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• 2011

The quantity of a discharge load can change with changes in rainfall in the area with a combined sewer system (CSS). To evaluate the implementation appropriately in the management of total maximum daily loads (TMDLs), the effects of rainfall changes should be considered in the estimation of the discharge load. The rainfall condition for the estimation of the discharge load in a certain year should be standardized to the same rainfall condition as that of the reference year. However, the calculation process is very complicated with its potential limitations. This study investigated and developed relatively simple methods for estimating the discharge load. Load conversion method (LCM) is designed to convert the discharge load under the current rainfall condition into that of the reference rainfall conditions. Simple rainfall data method (SRDM) is to simplify the estimation process of the discharge load by the simple conversion of rainfall data. These methods were applied to calculate the discharge load and examine the estimation results. From the results of this study the application of these methods may be useful for estimating the discharge load in the TMDL process.

• 대한토목학회논문집
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• 제31권5B호
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• pp.475-481
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• 2011

유역관리제도로써 시행 중인 현재의 수질오염총량관리제도의 기준유량은 과거 10년 평균저수량을 적용하고 있으며, 오염총량관리 이행평가는 단위유역별 목표수질을 만족할 수 있는 부하량에 대한 관리를 통해 시행되고 있다. 현재의 단순화되고 평균화된 개념의 기준유량을 이용한 단위유역별 부하량 할당과 관리는 목표수질 달성이라는 규제 기준을 달성하기 위한 관리측면에서의 편리성은 있으나 유역관리를 통한 유역 혹은 수체의 건전한 회복과 평가를 통해 문제점을 도출하고 해결하고자 하는 근본적인 유역관리의 역할은 미흡하다. 동일한 수질 농도를 유지, 관리하기 위해서는 매시간, 매일 변동하는 유량, 즉 전체유량을 고려한 부하량 관리를 통해서만 하천 생태계의 건강성을 유지할 수 있으며 이를 위해서는 전체 유량 규모를 고려해야 한다. 전체 유량 규모를 고려한다는 의미는 자연 현상인 강우-유출에 의해 다양하게 변동되는 유량과 인위적인 조절 유량 등을 고려한 오염총량관리 기준 설정과 이러한 양상을 반영한 과학적, 합리적인 평가가 가능하다는 의미이다. 이에 본 연구에서는 전체 유량 규모가 고려되는 유량-부하량 상관곡선을 이용한 오염총량평가 기법을 개발하고 이를 낙동강 수질오염총량관리 단위유역에의 실적용을 통해 문제점과 개선방향을 도출하고 본 기법의 국내 오염총량관리의 부하량 할당 및 이행평가에의 적용 가능성을 평가하였다.

• 한국지리정보학회지
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• 제24권3호
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• pp.41-57
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• 2021

본 연구는 대청호 상류에 있는 서화천 유역을 대상으로 SWAT(Soil and Watershed Assessment Tool) 모형을 이용한 수질 관리 대책 적용 및 부하지속곡선(LDC, Load Duration Curve)을 이용한 대책의 효율을 평가하였다. 수질 관리 대책으로는 인공습지, 방치 축분 저감, 비닐하우스 유출량 저감, 생태하천 복원, LID(Low Impact Development) 기술 적용, 점오염원 관리를 적용하였다. 적용된 기술은 부하지속곡선을 통해 유황별 목표 수질 초과율 및 부하량 저감 정도를 이용하여 수질 개선대책의 효율을 평가하였다. 부하지속곡선은 SWAT를 이용하여 장기 유량지속곡선(FDC, Flow Duration Curve)을 만들고 목표 수질을 곱하여 작성하였으며 목표 수질은 서화천 하류에 있는 옥천천 수질 관측지점의 10년간 자료를 사용하여 60분위에 해당하는 값을 목표 수질로 설정하였다. 본 연구를 통하여 여러 가지 수질 대책을 SWAT 모형을 통해 적용 가능성을 확인할 수 있으며 부하지속곡선을 통하여 유황에 따른 시기별 적용 가능성을 검토할 수 있었다.

• 대한전기학회논문지:전력기술부문A
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• 제53권8호
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• pp.466-471
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• 2004

Electricity industries throughout the world are undergoing unprecedented changes. As a result, these changes lead to the separation of traditional integrated utilities and the introduction of competition in order that increase efficiency in electricity industry. Direct load control (DLC) system in competitive electricity market has a hierarchical interactive operation system, therefore, its control logic is also applied by bilateral interactive method that interchanges information related to interruptible load between operation hierarchies. Consequently, load curtailment allocation algorithm appropriate for new DLC system is required, and based on interchanged information, this algorithm should be implemented by most efficient way for each operation hierarchy. In this paper, we develop the load curtailment allocation algorithm in an emergency for new DLC system. Especially, the optimal algorithm for load aggregator (LA) that participates in competitive electricity market as a main operator for load management is developed.