• Title/Summary/Keyword: Time-based Control

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Automatic Detection of Malfunctioning Photovoltaic Modules Using Unmanned Aerial Vehicle Thermal Infrared Images

  • Kim, Dusik;Youn, Junhee;Kim, Changyoon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.34 no.6
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    • pp.619-627
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    • 2016
  • Cells of a PV (photovoltaic) module can suffer defects due to various causes resulting in a loss of power output. As a malfunctioning cell has a higher temperature than adjacent normal cells, it can be easily detected with a thermal infrared sensor. A conventional method of PV cell inspection is to use a hand-held infrared sensor for visual inspection. The main disadvantages of this method, when applied to a large-scale PV power plant, are that it is time-consuming and costly. This paper presents an algorithm for automatically detecting defective PV panels using images captured with a thermal imaging camera from an UAV (unmanned aerial vehicle). The proposed algorithm uses statistical analysis of thermal intensity (surface temperature) characteristics of each PV module to verify the mean intensity and standard deviation of each panel as parameters for fault diagnosis. One of the characteristics of thermal infrared imaging is that the larger the distance between sensor and target, the lower the measured temperature of the object. Consequently, a global detection rule using the mean intensity of all panels in the fault detection algorithm is not applicable. Therefore, a local detection rule was applied to automatically detect defective panels using the mean intensity and standard deviation range of each panel by array. The performance of the proposed algorithm was tested on three sample images; this verified a detection accuracy of defective panels of 97% or higher. In addition, as the proposed algorithm can adjust the range of threshold values for judging malfunction at the array level, the local detection rule is considered better suited for highly sensitive fault detection compared to a global detection rule. In this study, we used a panel area extraction method that we previously developed; fault detection accuracy would be improved if panel area extraction from images was more precise. Furthermore, the proposed algorithm contributes to the development of a maintenance and repair system for large-scale PV power plants, in combination with a geo-referencing algorithm for accurate determination of panel locations using sensor-based orientation parameters and photogrammetry from ground control points.

Physicochemical and Microbial Characteristics of Oiji Prepared with Dry Salting Methods during Low Temperature Storage (저염 건식절임법으로 제조한 오이지의 저온저장 중 이화학적$\cdot$미생물학적 품질특성)

  • Kwon Oh-Yun;Yang Yun-Hyoung;Park Wan Soo;Kim Mee Ree
    • Korean journal of food and cookery science
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    • v.21 no.4 s.88
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    • pp.545-555
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    • 2005
  • The physicochemical and microbial characteristics of Oiji prepared with dry salting method, which has been used industrially for industry, were investigated. Low salting and low storage temperature were employed:extremely low salting extremely low temperature; ESET $(5\%,\;0^{\circ}C)$, very low salting extremely low temperature;VSET $(10\%,\;0^{\circ}C)$, extremely low salting very low temperature; ESVT$(5\%,\;5^{\circ}C)$, low salting very low temperature; VSVT$(10\%,\;5^{\circ}C)$ and high salting low temperature;HSLT$(30\%,\;10^{\circ}C)$ for control. Acidity was lower, and pH was higher in VSET, in of which the fermentation pattern was similar with that of HSLT The time required to reach the optimum acidity ($0.3\%$ lactic acid) was longer delayed for VSET (168 days), than for compared to ESVT (51 days). During storage of Oiji, greenness (-a) as measured with of the Hunter color system wasshowed the highest in VSET, and the lowest while in ESVT, the lowest. Total microbial and lactic acid bacteria counts number were the lowest in HSLT and VSET and were the lowest than in other groups, while the highest in ESVT. Yeast was not detected in HSLT, but was the highest while in VSVT. E coli coliform and listeria were detected in the $5\%$ salting groups, although Salmonella was not detected in any of the all groups. Texture profile analysis demonstrated exhibited that fracturability and hardness were highest in HSLT and VSET, compared to the other groups. Scores of over-all preference for ESVT and HSLT were higher atwith 6.3 and 6.2, respectively, compared to the other products. Based on these results, lower saltiness less than $10\%$ and lower storage temperature (less than $5^{\circ}C$) condition was optimum for maximizing the better for good quality of industrial Oiji preparation in industry.

Risk Factors of Readmission to Hospital for Pneumonia in Children (소아 폐렴의 재입원에 대한 위험인자)

  • Hong, Yu Chan;Choi, Eom Ji;Park, Sin-Ae
    • Pediatric Infection and Vaccine
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    • v.24 no.3
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    • pp.146-151
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    • 2017
  • Purpose: We analyzed the risk factors affecting readmission of children with pneumonia. Methods: We retrospectively analyzed the medical records of pediatric patients admitted to the Department of Pediatrics at the Jeonju Presbyterian Medical Center from January 2007 to August 2016. We classified patients who were readmitted with pneumonia within 30 days of discharge as the readmission group and patients who were admitted with pneumonia for the first time as the first admission group. Results: Among 158 patients, the study (readmission) group included 82 patients and the control (first admission) group included 76 patients. Age, the percentage of segmented neutrophils and lymphocytes, the number of admissions in the last 12 months, the associated diseases (respiratory diseases such as asthma), and the affection of the right upper lung were analyzed as risk factors for readmission. However, based on a regression analysis, only age and associated diseases were found to be significant risk factors. The rate of readmission increased with younger age. When there were associated diseases, the rate of readmission also increased. Conclusions: Young age and associated diseases were significant risk factors for readmission for patients with pediatric pneumonia. When pediatric patients are admitted with pneumonia, if they are young and/or have associated diseases, a comprehensive approach is needed to reduce the rate of readmission with careful consideration of precise examination, treatment, timing of discharge, and follow-up.

Reliability of a Questionnaire for Women's Reproductive History (여성의 출산력과 초경 및 폐경 연령에 대한 설문지의 신뢰도)

  • Ko, Kwang-Pil;Park, Sue-Kyung;Kim, Yeon-Ju;Bae, Ji-Suk;Jun, Jae-Kwan;Gwack, Jin;Yoo, Keun-Young
    • Journal of Preventive Medicine and Public Health
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    • v.41 no.3
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    • pp.181-185
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    • 2008
  • Objectives : This study was performed to evaluate the reproducibility of a questionnaire concerned with reproductive history and to ascertain which characteristics of the subjects (age, the visit-revisit intervals, education and chronic disease) are associated with good reliability in the Korean Multi-Center Cancer Cohort (KMCC) study. Materials and Methods: A total of 19,688 participants were enrolled between 1993 and 2004. Among them, we selected 386 participants who were aged 40 or more and who re-visited within 8 years after the first visit. Reliability was measured by the percent agreement according to error range for the continuous variables and the percent agreement and kappa statistics for the categorical variables. Results : The pregnancy histories were reliable (kappa=0.67) and the reasons for being menopausal among the postmenopausal women were also reliable (kappa=0.92). The percent agreement of the breast-feeding history was high (96.1%), although the kappa statistic was low. For the continuous variables, when the error range of one variable was considered to be reliable, the percent agreement of the age at menarche and the age at the first full term pregnancy was good (69.4% and 83.6%), whereas that of the age at menopause was low (51.5%). The factors associated with high reliability were a younger age, the presence of chronic disease and a short visit-revisit time interval. Conclusions : The agreements for parity, the reasons for menopause, and the breastfeeding history in the reproductive history questionnaire used in the KMCC were relatively good. The questionnaire for the menarche age and the menopausal age might have lower reliability due to the difference between Korean age and American age. To obtain reliable information, more attention should be given to the items in questionnaire-based surveys, and especially for surveying old-aged women.

Investigating Applicability of Unmanned Aerial Vehicle to the Tidal Flat Zone (조간대 갯벌에서 무인항공기 활용 가능성에 관한 연구 - 수치표고모델을 중심으로 -)

  • Kim, Bum-Jun;Lee, Yoon-Kyung;Choi, Jong-Kuk
    • Korean Journal of Remote Sensing
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    • v.31 no.5
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    • pp.461-471
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    • 2015
  • In this study, we generated orthoimages and Digital Elevation Model (DEM) from Unmanned Aerial Vehicle (UAV) to confirm the accuracy of possibility of geospatial information system generation, then compared the DEM with the topographic height values measured from Real Time Kinematic-GPS (RTK-GPS). The DEMs were generated from aerial triangulation method using fixed-wing UAV and rotary-wing UAV, and DEM based on the waterline method also generated. For the accurate generation of mosaic images and DEM, the distorted images occurred by interior and exterior orientation were corrected using camera calibration. In addition, we set up the 30 Ground Control Points (GPCs) in order to correct of the UAVs position error. Therefore, the mosaic images and DEM were obtained with geometric error less than 30 cm. The height of generated DEMs by UAVs were compared with the levelled elevation by RTK-GPS. The value of R-square is closely 1. From this study, we could confirm that accurate DEM of the tidal flat can be generated using UAVs and these detailed spatial information about tidal flat will be widely used for tidal flat management.

Fuzzy Logic Based Modeling of an Incident Detection Algorithm (퍼지이론을 이용한 유고감지 알고리즘)

  • 이시복
    • Journal of Korean Society of Transportation
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    • v.14 no.2
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    • pp.137-155
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    • 1996
  • 본 논문은 다이아몬드 인터체인지에서의 유고감지모형 개발을 위해 퍼지이론을 응용한 연구를 문서화 한 것이다. 지금까지의 교차로와 일반도로(고속도로가 아닌)에서의 유고감지에 관한 연구는 초기에 불과하다. 기존의 알고리즘들은 필요한 데이터 보존의 어 려움과 유고감지의 특성과 관련된 기술적 어려움을 효과적으로 극복하지 못하고 있다. 본 연구의 목적은 다이아몬드 인터체인지에서의 유고감지를 위한 새로운 모형을 개발하는데 있다. 이 연구를 통하여 개발된 유고감지 모형은 차량차단 유고(lane-blocking incidents) 를 감지하는데, 감지의 범위는 차량차단 유고의 경향이 교통 장황에 특정한 패턴을 형성 하고 그에 따른 신호제어전략의 조정이 요구될 때에 국한된다. 이 모형은 전통적인 통계 치를 이용한 유고감지감 고유의 문제를 해결하며, 보다 정확하고 신뢰성 있는 유고감지를 위해 다양한 교통변수를 이용하여 전체적인 유고의 경향을 포착한다. 또한 이 모형은 실 시간 교통대응 다이아몬드 인터체인지 신호제어 시스템 (real-time traffic adaptive diamond interchange control system)의 구성요소로써 사용되며, 그리고 더 큰 교차로 시스템에의 상용을 위하여 확장이 용역하도록 설계되었다. 본 연구를 통해 개발된 프로 토타입(prototype) 유고감지 모형은 실제의 다이아몬드 인터체인지에 적용되어, 감지율, 오보율, 평감지시간의 세 달로써 성능이 평가되었다. 모형의 성능평가 결과는 무적이었으 며, 퍼지이론은 유고감지에 효과적인 접근방법임을 확인할 수 있었다.투자의 타당성을 실증적으로 보여 주고 있다.산정 절차 정립에 엇갈림 알고리즘을 활용하는 방안을 제시하였다.자함수를 추정한 뒤 이를 이용해 업종, 기업규모, 상품유형별로 적합한 모델(Fixed Effects Model)을 결정하고, 각각에 해당하는 통계모형을 구축하였다. 이 결과 (1) 업종 및 기업규모별로 그룹간에 유의한 특성이 발견되었으며, (2) R&D 및 광고투자는 기업의 시장성과를 설명하는 중요한 변수이나, (3) R&D 투자의 경우는 광고에 비해 불확실성이 존재하는 것으로 나타났고, (4) 수리모형에서 도출된 한계원리가 통계모형에서도 유효한 것으로 드러났다.등을 토대로 한 10대 산업을 육성하기 위하여 과학기술부는 기술수요조사를 바탕으로 49개 주요기술을 도출하여, 과학기술 일류 국가 실현, 국민소득 2만불 달성이라는 국가적 슬로건을 내걸고 “차세대 성장동력” 창출을 위한 범정부차원의 기획과 연구비의 집중투자를 추진하고 있다.달성하기 위해서는 종합류류 전산망의 시급한 구축과 함께 화물차의 적재율을 높이고 공차율을 낮출 수 있는 운송체계의 수립이 필요한 것으로 판단된다. 그라나 이러한 화물전용차선의 효과는 단기적인 치유책일 수밖에 없기 때문에 물류유통 시설의 확충을 위한 사회간접자본의 구축을 서둘러 시행하여야 할 것이다.으로 처리한 Machine oil, Phenthoate EC 및 Trichlorfon WP는 비교적 약효가 낮았다.>$^{\circ}$E/$\leq$30$^{\circ}$NW 단열군이 연구지역 내에서 지하수 유동성이 가장 높은 단열군으로 추정된다. 이러한 사실은 3개 시추공을 대상으로 실시한

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Development of Power Management Strategies for a Compound Hybrid Excavator (복합형 하이브리드 굴삭기를 위한 동력전달계 제어기법 연구)

  • Kim, Hak-Gu;Choi, Jae-Woong;Yoo, Seung-Jin;Yi, Kyoung-Su
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.12
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    • pp.1537-1542
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    • 2011
  • This paper presents the power management strategies for a compound hybrid excavator. The compound hybrid excavator has been replaced the hydraulic swing motor to the electric swing motor. This excavator requires a proper control algorithm to regulate the energy flow between the mechanical coupling and the electric devices. The controller should improve fuel economy and maintain the super capacitor voltage within a proper range. A thermostat controller and ECMS controller are designed such that these objectives can be achieved. The thermostat controller regulates the power of the engine-assist motor on the basis of the super capacitor voltage, and the ECMS controller determines it using the real-time fuel minimization strategy based on the concept of equivalent fuel. Simulation results showed that by using the hybrid excavator, the fuel economy becomes about 20% higher than that obtained using the conventional excavator and that the ECMS controller outperforms the thermostat controller.

A Study on the Method of Energy Evaluation in Water Supply Networks (상수관망의 에너지 평가기법에 관한 연구)

  • Kim, Seong-Won;Kim, Dohwan;Choi, Doo Yong;Kim, Juhwan
    • Journal of Korea Water Resources Association
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    • v.46 no.7
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    • pp.745-754
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    • 2013
  • The systematic analysis and evaluation of required energy in the processes of drinking water production and supply have attracted considerable interest considering the need to overcome electricity shortage and control greenhouse gas emissions. On the basis of a review of existing research results, a practical method is developed in this study for evaluating energy in water supply networks. The proposed method can be applied to real water supply systems. A model based on the proposed method is developed by combining the hydraulic analysis results that are obtained using the EPANET2 software with a mathematical energy model on the MATLAB platform. It is suggested that performance indicators can evaluate the inherent efficiency of water supply facilities as well as their operational efficiency depending on the pipeline layout, pipe condition, and leakage level. The developed model is validated by applying it to virtual and real water supply systems. It is expected that the management of electric power demand on the peak time of water supply and the planning of an energy-efficient water supply system can be effectively achieved by the optimal management of energy by the proposed method in this study.

A Study on the Cadastral Characteristics of Dokdo-ri (독도리의 지적 특성 연구)

  • Lee, Beom-Gwan
    • Journal of Cadastre & Land InformatiX
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    • v.49 no.2
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    • pp.5-21
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    • 2019
  • The purpose of this study is to investigate and analyze the cadastral transformation process of Dokdo-ri based on the institutional concept of the cadastre, while presenting the cadastral characteristics of Dokdo-ri therefrom. For this purpose, both the literature search method and the Internet search method were used. As for the analysis method, descriptive analysis method and comparative analysis method were used. The findings support that the cadastral characteristics of Dokdo-ri is drawn as follows: First, from the physical point of view, the cadastral characteristics of Dokdo-ri shows that the territory is given by the smallest lot numbers in the country and that the territory is also given by the land lot number consisting of small size lots without continuing the ground for which the cadastral resurvey project was carried out for the first time. Second, in terms of the rights, the cadastral characteristics of Dokdo-ri shows that the entire area given by the lots is owned by a single owner and no ownership has been changed. Third, in terms of its value, the cadastral characteristics of Dokdo-ri shows that it is the only area given by the lots of which the officially assessed individual land price has never been decreased in the entire lots. Fourth, when it comes to presenting the cadastral characteristics of Dokdo-ri in terms of the use control/restriction, the consciousness of preserving Dokdo-ri and the consciousness of enhancing real territory are confronted but due to the Cultural Heritage Protection Act etc, the cadastre turned out to be a very passive cadastral work.

Estimation of Saturation Velocity in Soils During Rainfall using Soil Box Test (모형토조실험을 이용한 강우시 토층의 포화속도 산정)

  • Kim, Chul-Min;Song, Young-Suk;Kim, Hak-Joon
    • The Journal of Engineering Geology
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    • v.25 no.3
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    • pp.377-385
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    • 2015
  • We constructed a model test apparatus to evaluate the dependence of the saturation velocity (Vs) in soils on rainfall intensity (IR). The apparatus comprises a soil box, a rainfall simulator, and measuring sensors. The model grounds (60 cm × 50 cm × 15 cm) were formed by Joomunjin standard sand with a relative density of 75%. The rainfall simulator can control the rainfall intensity to reenact the actual rainfall in a soil box. Time Domain Reflectometer (TDR) sensors and tensiometers were installed in the soils to measure changes in the volumetric water content and matric suction due to rainfall infiltration. During the tests, the soil saturation was determined by raising the groundwater table, which was formed at the bottom of the soil box. [Please check that the correct meaning has been maintained.] The wetting front did not form at the ground surface during rainfall because the soil particles were uniform and the coefficient of permeability was relatively high. Our results show that the suction stress of the soils decreased with increasing volumetric water content, and this effect was most pronounced for volumetric water contents of 20%-30%. Based on a regression analysis of the relationship between rainfall intensity and the average saturation velocity, we suggest the following equation for estimating the saturation velocity in soils: Vsavg (cm/sec) = 0.068IR (mm/hr).