• 제목/요약/키워드: Work sampling

검색결과 727건 처리시간 0.027초

Monitoring water injection with borehole ERT: preliminary results of an experiment carried out in Sindos (N. Greece)

  • Tsourlos, Panagiotis;Kim, Jung-Ho;Vargemezis, George;Yi, Myeong-Jong
    • 한국지구물리탐사학회:학술대회논문집
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    • 한국지구물리탐사학회 2007년도 공동학술대회 논문집
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    • pp.87-92
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    • 2007
  • This work describes the installation and preliminary measurements of an electrical resistivity tomography (ERT) system to monitor the injection of recycled water into a confined aquifer in the area of Sindos (Thessaloniki N. Greece). The aim is to provide, through time-lapse ERT measurements and processing, geoelectrical images of rather increased volumetric sampling around and between the holes and to obtain improved understanding of the flow and transport of the injected water. The details about the general setting, the construction and installation of the ERT cables into the boreholes are explained in full. Preliminary measurements involving single and cross-hole ERT measurements were obtained and processed with a 2D inversion algorithm to produce images of the subsurface. Results depict a very good correlation between ERT images and the lithology and resistivity logs; an indication of the reliability of the approach.

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확산포집-이온크로마토그래프법을 이용한 대기중 SOx의 자동정량 (Automated Determination of SOx in Air by Diffusion Scrubber-lon Chromatography)

  • 이용근;이동수;백선영
    • 한국대기환경학회지
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    • 제11권4호
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    • pp.307-313
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    • 1995
  • An automatic method is developed for the determination of SOx in atmosphere. The method involves SOx sampling in diffusion scrubber followed by ion chromatographic analysis. Filtered air is withdrawn at 1.8.ell./min through a diffusion scrubber of which inner tube is made of PTFE(Gore-tex) membrane tubing. 1mM $H_{2}$ $O_{2}$ is used as absorbing solution so that SOx is oxidized to S $O_{4}$$^{2-}$. The scrubbered solution is automatically injected into ion chromatograhpy eith conductivity detection for sulphate determination. Replacement of commonly used polyproplene membrane with PTFE gives several merits such as easy preparation of diffusion scrubber, better collection efficiency. No measurable memory effect is experienced, and this isin contrast to previous work for ammonia. Detection limit of this method defined by three times standard deviation is 0.56ppbv. The precision is 0.4% RSD at SOx concentration of 7.3ppbv Results for Seoulatmosphere ate presented.

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작업자세에 의한 자동차 조립작업의 작업부하평가 (Workload Evaluation of Automobile Assembly Task Using a Posture Classification Schema)

  • 정재원;정민근;이인석;김상호;이상민;이유정
    • 대한인간공학회:학술대회논문집
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    • 대한인간공학회 1997년도 추계학술대회논문집
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    • pp.437-440
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    • 1997
  • The association of poor body postures with pains or symptoms of musculoskeletal discorders has been reported by many researchers. An ergonomic evaluation of postural stresses as well as biomechanical stresses is also important especially when a job involves highly repetitive or prolonged poor body postures. The human body is divided into five parts: shoulder/upper arm, lower arm/wrist, back, neck, lower extremities. A work-sampling based macropostural classification system was developed to characterize various postures in this study. Application of the posture classification schema developed in this study to 7 automobile assembly tasks showed that the schema can be used as a tool to didntify the operation and tasks involving highly stressful body postures. This posture classification schema can also be applied as a basis for quantitive evaluating the workload of manual task.

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한국 치과기공사의 노후 준비에 관한 연구 (A Study about Preparation of old age of Korean dental technicians)

  • 이선경
    • 대한치과기공학회지
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    • 제37권3호
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    • pp.145-155
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    • 2015
  • Purpose: The Purpose of the study is to investigate the need for the preparation of old age of Korean dental technicians. Methods: A total of 778 dental technicians were selected by proportional stratified by region compared to extraction sampling from a list of Korea dental technician Association in 2012. The final sample size was 386. Questionnaires consisted of 9 general characteristics, recognition of old age 4, and preparation of old age 9 on a Liken 5 scale. Cronbach's alpha was 0.784 in the study. All statistical analyzed were performed using SPSS 14.0(Statistical Packages for Social Science Ver. 14.0. Chicago, IL, USA). Results: Factors affecting the aging preparation is gender, age, clinical career, work place(p<0.001). Conclusion: This study suggested that preparation for old age of Korean dental technicians was very important and the preparation must be connected with the social welfare policy.

Herschel/SPIRE Galaxies in the NEP-Wide Field - Preliminary Results

  • Kim, Seong Jin;Jeong, Woong-Seob;Lee, Hyung Mok
    • 천문학회보
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    • 제41권1호
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    • pp.66.3-66.3
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    • 2016
  • We report preliminary results from our analyses on the star-forming galaxies in the Herschel/SPIRE survey data over the AKARI/NEP-Wide Field. In this work, we utilize a combination of the SPIRE point source catalogue containing ~ 4,800 sources distributed over the wide (5.6 sq. deg) field and the spectroscopic redshift (zSPEC) data for 1790 selected targets obtained by MMT/Hectospec and WIYN/Hydra. Our analyses take advantages of multi-wavelengths photometric data (28 bands at most) covering from u* to $500{\mu}m$ band as well as continuous MIR wavelengths sampling by AKARI and WISE (4 to $25{\mu}m$). Various physical properties such as total infrared luminosity (LTIR), star formation rate (SFR), and luminosity functions (LFs) will be presented.

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$320{\times}256$ 초점면배열 적외선 검출기를 위한 고성능 저 전력 신호취득회로의 제작 (Fabrication of High Performance and Low Power Readout Integrated Circuit for $320{\times}256$ IRFPA)

  • 김치연
    • 한국군사과학기술학회지
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    • 제10권2호
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    • pp.152-159
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    • 2007
  • This paper describes the design, fabrication, and measurement of ROIC(ReadOut Integrated Circuit) for $320{\times}256$ IRFPA(InfraRed Focal Plane Array). A ROIC plays an important role that transfer photocurrent generated in a detector device to thermal image system. Recently, the high performance and low power ROIC adding various functions is being required. According to this requirement, the design of ROIC focuses on 7MHz or more pixel rate, low power dissipation, anti-blooming, multi-channel output mode, image reversal, various windowing, and frame CDS(Correlated Double Sampling). The designed ROIC was fabricated using $0.6{\mu}m$ double-poly triple-metal Si CMOS process. ROIC function factors work normally, and the power dissipation of ROIC is 33mW and 90.5mW at 7.5MHz pixel rate in the 1-channel and 4-channel operation, respectively.

Kinodynamic Motion Planning with Artificial Wavefront Propagation

  • Ogay, Dmitriy;Kim, Eun-Gyung
    • Journal of information and communication convergence engineering
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    • 제11권4호
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    • pp.274-281
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    • 2013
  • In this study, we consider the challenges in motion planning for automated driving systems. Most of the existing online motion-planning algorithms, which take dynamics into account, find it difficult to operate in an environment with narrow passages. Some of the existing algorithms overcome this by offline preprocessing if environment is known. In this work an online algorithm for motion planning with dynamics in an unknown cluttered environment with narrow passages is presented. It utilizes an idea of hybrid planning with sampling- and discretization-based motion planners, which run simultaneously in a full configuration space and a derived reduced space. The proposed algorithm has been implemented and tested with a real autonomous vehicle. It provides significant improvements in computational time performance over basic planning algorithms and allows the generation of smoother paths than those generated by the recently developed hybrid motion planners.

지연보상 동기복조방법에 의한 소프트웨어 레졸버-디지털 변환기 (Software-Based Resolver-to-Digital Converter by Synchronous Demodulation Method including Lag Compensator)

  • 김윤현
    • 전기학회논문지
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    • 제62권6호
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    • pp.756-761
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    • 2013
  • This paper propose the new demodulation method that can detect resolver signal's peak at the time of position estimation when the position information is required during current controller period. The proposed method is performed in a synchronous demodulation way with exciting signal and also cover a capability which can compensate the lag element of exciting signal caused by the resolver's inductive component and filter circuit. This paper carried out the experiment to investigate the validity and performance of the suggested method by using the test board made up of DSP and demodulation circuit. The test results show that the proposed method is theoretically clear and work completely as expected from making sure of sampling resolver signal's peak at the time of position estimation. In addition, Software position tracking algorithm is executed with the demodulated signals generated by the suggested method and an exact position can be estimated.

Multi-Objective Optimal Design of a Single Phase AC Solenoid Actuator Used for Maximum Holding Force and Minimum Eddy Current Loss

  • Yoon, Hee-Sung;Eum, Young-Hwan;Zhang, Yanli;Koh, Chang-Seop
    • Journal of Electrical Engineering and Technology
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    • 제3권2호
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    • pp.218-223
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    • 2008
  • A new Pareto-optimal design algorithm, requiring least computational work, is proposed for a single phase AC solenoid actuator with multi-design-objectives: maximizing holding force and minimizing eddy current loss simultaneously. In the algorithm, the design space is successively reduced by a suitable factor, as iteration repeats, with the center of pseudo-optimal point. At each iteration, the objective functions are approximated to a simple second-order response surface with the CCD sampling points generated within the reduced design space, and Pareto-optimal solutions are obtained by applying($1+{\lambda}$) evolution strategy with the fitness values of Pareto strength.

상수도 배관망에서의 수질변화에 관한 연구 (수질악화의 영향인자 분석과 잔류염소 모델링) (A study on Water Quality Changes in Distribution System (Factor analysis of deterioration of water quality & Modelling of free chlorine))

  • 이현동;정원식;문숙미
    • 상하수도학회지
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    • 제11권3호
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    • pp.59-66
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    • 1997
  • Although it produces well-treated water in water treatment plant, water quality at the tap can be changed depending on the state of pipes. It is because water quality deteriorates as plant water passes through pipeline networks. Therefore, the improvement of not only water treatment technology but also O & M of water pipelines is required to supply good water to consumers. The purpose of the study was to obtain the basic data of control technology for water quality in pipes through investigating water quality in distribution system. We selected 11 sampling sites and investigated water quality from plant to endpoint of distribution system. we also simulated decreasing tendency of free chlorine through pipeline network. As the result of water quality test, all parameters were below allowable levels, but some parameters had the possibility of being over levels. So there must be more work to set up proper countermeasure for violable parameters.

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