• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.477-478
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• 2007

This paper proposes a new concept of support vector machine (SVM) based voltage stability classifier using time-series phasor data. The classifier, based on a linear SVM, can provide very effective signals for identification of long-term voltage stability. In addition, the SVM output is applicable as an voltage stability indicator when an amount of corrective controls are performed just to make the system reach around at the maximum deliverable point.

• Journal of Food Hygiene and Safety
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• v.33 no.1
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• pp.38-43
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• 2018

A few authors have already investigated microbial contamination of leafy vegetables in distribution condition and examined the effect of temperature abuse on microbial safety or product quality. But this study analyzed proliferation of indicator microorganisms and food poisoning bacteria in real situation in Korean agroindustry and investigated washing effect of micobial contamination on leaf surface. Leafy vegetables were found to be contaminated with aerobic bacteria at $0.1{\sim}0.32{\times}10^3CFU/g$. Staphylococcus aureus and Bacillus cereus were detected in leafy vegetables at $0{\sim}0.54{\times}10^3CFU/g$. However, Salmonella spp., Coliforms, Clostridium spp. and Listeria spp. were not detected in any samples. Indicator microorganisms and food poisoning bacteria on leafy vegetables increased at room temperature when simulatively distributed condition. After clean-up, the indicator microorganisms and food poisoning bacteria of kimchi cabbage, lettuce and perilla leaf were decreased to a very low level. This study suggests that it is necessary to improve the level of hygiene management such as use of cold chain system and hygiene management of transport tools during the distribution process for fresh leafy vegetables.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.4
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• pp.436-442
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• 2011

To obtain the engine output correctly is basically very important factor for estimating a engine performance. But, it has been reported that the IHP measured from electronic indicator such as MIPS(Mean Indication Pressure System) has a deviation compared to mechanical indicator. It was reported by authors that the uncertainty of crank angle for TDC position could be one of the reasons. In this paper, the uncertainty of crank angle for TDC position and its influence to engine output were investigated respectively about M/E and G/E for marine diesel engines. For the purpose, two sampling methods of pressure in cylinder were considered which were 'angle base sampling' and 'time base sampling'. Angle base sampling is real crank angle acquired from angle encoder which is attached to crank shaft and time base sampling is crank angle calculated by detected revolution with Z-pluse of encoder. Time base sampling is same method of MIPS. This paper concluded that time base sampling method is not suitable for obtaining the output of marine diesel engine on board because of instantaneous speed variation and load fluctuation. Also it is verified that the variation of engine speed by load fluctuation should be one of reasons additionally in case of M/E.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.1
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• pp.34-42
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• 2012

This study aims to suggest the secure indicator of parks and green areas according to the properties of the location. There were 31 study areas where negotiation was finalized from 2001 to 2008. The location types were divided by land use type before development and the ratio of mountainous and constructed parks, the ratio of green change and so forth were analyzed according to the those types. As a result, location types were classified into mountainous type, arable land type, urban district type. In terms of locational property, even though the ratio of parks and green areas was the highest at 24.9% in arable land type, the ratio was not much different from the others. Mountainous type depends on the ratio of mountainous park with 10.5%, and arable land type, and urban district type has high ratio of constructed parks. And, the ratio of green change arable land type is degraded by 32.8% and the ratio of mountainous green change is serious in the mountainous type. As a result of the selection of negotiation indicator, arable land type is closely related to the ratio of parks and green areas and the ratio of green change; mountainous type, the ratio of park and green, the ratio of mountainous green change and the ratio of constructed park and green; urban district type, the ratio of green areas.

• Korean Journal of Ecology and Environment
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• v.42 no.2
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• pp.212-220
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• 2009

In this study, we analyzed fish compositions and ecological characteristics such as trophic guilds and tolerance guilds in association with water quality characteristics in Masan Reservoir during November 2008. Total number of species were 12 species (6 families) and the dominant species were Zacco platypus, Hemiculter eigenmanni, and Pseudorasbora parva. We found three Korean endemic species and one exotic species, Carassius cuvieri. According to the analysis of ecological indicator characteristics, relative proportion of tolerant and omnivore species was 98% of the total indicating that probably, the fauna was influenced by physical habitat disturbance and physicochemical degradations. Fish distribution analysis along with littoral zone showed that the most fishes (${\sim}$95%) were observed in the littoral zone where emerged macrophytes were well developed. Also, substrate analysis indicated that the most species were found near silt area (11 species, 91.7%), so that the significant differences were found between the substrate types. Analysis of water quality indicated that concentrations of total phosphorus (TP) and chlorophyll-a (ChI-a) as a lake trophic indicator were judged as eutrophic states, respectively and COD as an indicator of organic matter pollution averaged 10.9 mg $L^{-1}$. Based on the water quality, this system were influenced by the nutrient enrichments and organic matter. The degradations of water quality in Masan Reservoir resulted in trophic compositions of fish (increase of omnivore species) and the dominance of tolerant fish. This Monitoring data may contribute changes of fish fauna and compositions in relation to habitat modifications and chemical water quality degradations in the future.

• Journal of Environmental Health Sciences
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• v.47 no.2
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• pp.182-191
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• 2021

Objective: This study was performed to detect indicator bacteria in drinking spring water samples in Gwangju City and to identify their genus using the VITEK-II system. Methods: The subjects were ten drinking spring water sites in Gwangju. Samples of spring water were taken every month from September 2019 to August 2020. We analyzed for the indicator bacteria Yersinia and microorganisms isolated from the spring water. Result: According to the research results on indicator bacteria, general bacteria in st1-st7 with sterilization facilities in the spring and summer were investigated in the range of 0-2 CFU/mL and 0-12 CFU/mL. In st9, where a sterilization facility was not installed, the most general bacteria were detected (160 CFU/mL). Total coliform and fecal coliform showed unsatisfied rates of 16.7 and 11.1% in spring and 14.7 and 11.8% in summer, respectively. The unsatisfied rates of total coliform for the designated and non-designated spring water facilities were 3.8 and 47.1%, respectively, and for the fecal coliform group they were 2.5 and 35.3%. The difference was confirmed according to the presence of a sterilization facility. Yersinia spp. was not detected in all drinking spring water. Forty-one strains in 25 species were isolated from ten sites. The results classified as major dominant species are Pseudomonas spp. 14.6%, Pantoea spp. 9.8%, Serratia spp. 9.8%, Acinetobacter spp. 9.8%, Citrobacter spp. 7.3%, Bordetella spp. 7.3%, Delftia spp. 4.9%, and Enterobacter spp. 4.9%. Conclusions: Based on the result that various species derived from fecal pollution and artificial pollutants were detected in the non-specified public spring water facilities that many people use, the facilities need institutional complements such as continuous management or complete shutdowns.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.3
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• pp.279-284
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• 2020

This paper presents the conceptual design of a cooperative control with Energy Management System (EMS) and Distribution Management System (DMS). This control enables insufficient reactive power reserve in a power transmission system to be supplemented by surplus reactive power in a power distribution system on the basis of the amount of the needed reactive power reserve calculated by the EMS. This can be achieved, because increased numbers of microgrids with distributed energy resources will be installed in the distribution system. Furthermore, the DMS with smart control strategy by using surplus reactive power in the distribution system of the area has been gradually installed in the system as well. Therefore, a kind of hierarchical voltage control and cooperative control scheme could be considered for the effective use of energy resources. A quantitative index to evaluate the current reactive power reserve of the transmission system is also required. In the paper, the algorithm for the whole cooperative control system, including Area-Q Indicator (AQI) as the index for the current reactive power reserve of a voltage control area, is devised and presented. Finally, the performance of the proposed system is proven by several simulation studies.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.4
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• pp.123-129
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• 2013

The aim of this study is to design an intelligent pattern-based real-time trading system (PRTS) using rough set analysis of technical indicators, dynamic time warping (DTW), and genetic algorithm in stock futures market. Rough set is well known as a data-mining tool for extracting trading rules from huge data sets such as real-time data sets, and a technical indicator is used for the construction of the data sets. To measure similarity of patterns, DTW is used over a given period. Through an empirical study, we identify the ideal performances that were profitable in various market conditions.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.12
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• pp.1204-1208
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• 2014

As required performance of UAV (Unmanned Aerial Vehicle) becomes more complex and complicated, required positioning accuracy is becoming more and more higher. GPS is a reliable world wide positioning providing system. Therefore, UAV generally acquires position information from GPS. But when GPS is not available such as too weak signal or too less GPS satellites environments, UAV needs alternative positioning system such as network positioning system. RSSI (Received Signal Strength Indicator) based positioning, which is one method of network positioning technologies, determines its position using RSSI measurements containing distance information from AP (Access Point)s. In that method, a selected AP's configuration has strong and tight relationship with its positioning errors. In this paper, for, we additionally account AP's configuration information by adopting DOP (Dilution of Precision) into AP selection procedures and provide more accurate RSSI based positioning results.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.26 no.1
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• pp.37-43
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• 2018

There has been the migration to a performance-based approach in many areas which include transition planning at global, regional and local levels, performance-based navigation and safety management. Achieving continuous success of Air Traffic Management (ATM) systems would require a performance-based approach to raise productivity and efficiency of it through performance measurements and reviews. This paper considers establishment planning of performance measurement and evaluation system for ATM. Related to key performance areas proposed by International Civil Aviation Organization, performance indicators and metrics which could be used to measure and evaluate ATM performance are presented. Also, organizational system and operational planning for efficient operation of ATM are presented.