• Title/Summary/Keyword: Equivalent noise

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Reduction Chattering Error of Reed Switch Sensor for Remote Measurement of Water Meter (Reed Switch 센서를 이용한 원격 검침용 상수도 계량기에서 Chattering 오차 감소 방안 연구)

  • Ayurzana, Odgerel;Kwon, Jong-Won;Park, Yong-Man;Koo, Sang-Jun;Kim, Hie-Sik
    • Proceedings of the KIEE Conference
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    • 2007.04a
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    • pp.377-379
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    • 2007
  • To reduce the chattering errors of reed switch sensors used for automatic remote measurement of water supply system, a reed switch sensor was analyzed and improved. The operation of reed switch sensors can be described as a mechanical contact by approximation of permanent magnet piece to generate an electrical pulse. The reed switch sensors are used in measurement application by detecting the rotational or translational displacement. To apply for flow measurement devices, the reed switch sensors should keep high reliability. They are applied for the electronic digital type of water flow meters. The reed switch sensor is just installed simply on the mechanical type flow meter. A small magnet is attached on a pointer of the water meter counter rotor. Inside the reed sensor, two steel leaf springs make mechanical contact and apart as rotation of flow meter counter. The counting electrical contact pulses can be converted as the water flow amount. The MCU sends the digital flow rate data to the server using the wireless communication network. But it occurs data difference or errors by chattering noise. The reed switch sensor contains chattering error by it self at the force equivalent position. The vibrations such as passing car near to the switch sensor installed location. In order to reduce chattering error, most system uses just software methods for example using filter and also statistical calibration methods. The chattering errors were reduced by changing leaf spring structure using mechanical hysteresis characteristics.

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A Study of the Dynamic Amplification Characteristics of the Domestic Seismic Observation Sites Using Coda Wave (Coda파를 이용한 국내 관측소지반의 동적 증폭특성에 관한 연구)

  • Kim, Junkyoung;Lee, Jundae
    • Journal of the Korean GEO-environmental Society
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    • v.10 no.7
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    • pp.135-141
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    • 2009
  • For more reliable estimation of soil-structure interaction and seismic source and attenuation properties, site amplification function should be considered. This study use the Nakamura's method (1989) for estimating site amplification though various methods for the same purpose have been proposed. This method was originally applied to the surface waves of background noise and therefore there are some limitation for applications to general wave energy. However, recently this method has been extended and applied to the S wave energy successfully. This study applied the method to the coda wave energy which is equivalent to the backscattered S wave energy. We used more than 60 observed ground motions from 5 earthquakes which occurred recently, with magnitude range from 3.6 to 5.1 Each station showed characteristic site amplification property in low-, high- and resonance frequency ranges. In the case of comparing these results to those from S wave energy, lots of information to the site classification work can be gained. Moreover, removal of site amplification can give us more reliable seismic source parameters.

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Arc Discharge Sensor having Noise Immunity to Ambient Light (주변광 영향을 받지 않는 아크방전 감지 센서)

  • Roh, Hee Hyuk;Seo, Yong Ma;Khishigsuren, J.;Choi, Kyoo Nam
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2013.05a
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    • pp.726-728
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    • 2013
  • Optoelectronic arc discharge sensor was used to detect arc discharge inside power distribution panel. Arc discharge is fatal to power system once it begins, thus preventive detection is necessary before power failure occurs. Optoelectronic detection method was used to avoid direct electrical contact to power apparatus inside power distribution panel. 180 degree detection angle and detection range far exceeding 6m, which was sufficient for monitoring purpose, was achieved using the photodiode having $7.5mm^2$ of active surface area and flash source with $0.4cal/cm^2$ energy density, which is equivalent to 1.9J with $2.16cm^2$ emitting area. The response speed of arc discharge sensor was measured to be below 1 msec. The above optoelectronic arc discharge sensor was measured to be sensitive enough to detect 0.94 pC charge.

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A study on the work in fishing convention, 2007 and the fishing vessel's accommodation facilities standards in national fishing vessel act (ILO어선원노동협약과 어선법의 어선거주설비에 대한 고찰)

  • Kim, Wook-Sung;Park, Moon-Gap
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.46 no.4
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    • pp.466-475
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    • 2010
  • This study intends to present a direction for the better reforming of fishers'onboard living conditions and proposals for preparing for ratification of the Work in Fishing Convention by means of making a comparison between standards on recent national fishing vessel accommodation facilities and standards on the Work in Fishing Convention and Its Recommendation, 2007, ILO. For the most part of standards on national fishing vessel accommodation facilities are somewhat insufficient to satisfy the provisions in Annex III of the Convention. Considering by items on fishing vessel accommodation facilities, the standards on insect protector, noise and vibration, heating and air conditioning, lighting, persons per sleeping room, recreational facility are not provided in national law. Headroom, separation of accommodation, sleeping room floor area, mattress size, mess room, galley and food storage are partially sufficient for the Convention. In case of sanitary facilities, national standards are not sufficient for the Convention. The other side, facilities related safety of ship and crew such as emergency escape etc., are fully sufficient for the Convention. These insufficiencies caused by different types of fishing vessel depend on originality of fishing method and practices. In the comparison between equivalent tonnage about vessel's length on convention and calculated tonnage of national existing fishing vessel, the difference are 226tons about length 24m and 501tons about length 45m. For that reason, headroom, persons per sleeping room, cabin of sicker and injured, sanitary facilities may decide to use gross tonnage in place of length (L) and the alleviating measure basis of convention. But in case of standards on sanitary facilities which are unsufficient for the Convention, specially in coastal fishing vessel length basis should be adopted with alleviating basis for less than length 24m.

Study of Inter-Track Crosstalk in Holographic Read Only Memory to Determine Optimal Track Format (홀로그래픽 롬 시스템의 최적 트랙 포맷을 결정하기 위한 인접 트랙간 간섭 현상에 대한 연구)

  • Kim, Kun-Yul;Yoon, Pil-Sang;Kang, Byung-Bok;Park, Joo-Yeon;Nam, Ha-Eun
    • Transactions of the Society of Information Storage Systems
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    • v.1 no.2
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    • pp.150-154
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    • 2005
  • The effects of track format on the inter-track crosstalk of holographic ROM system are investigated. To quantify the effect of inter-track crosstalk for various track width and pitch, we defined Signal to Crosstalk noise Ratio(SCR) as a criterion. A numerical simulation is used to obtain the SCR as a function of track widths and pitches. We compared different 4 track widths having 0.3, 0.4, 0.5, and 0.6 ${\mu}m$ considering resolving power of lens and recording density. The simulation results show that the SCRs for each track width are maximized at the track pitch which has the value of 0.72, 0.72, 0.74, and 0.5 ${\mu}m$ respectively. Next, for the three sets with track width-pitch(0.4-0.72, 0.5-0.74, 0.6-0.8 ${\mu}m$) which showed the maximum SCR, we set a minimum pit length so that all sets have a DVD equivalent data density and compared RF signals passed from the slit. The simulation results show that when the track width, pitch, and minimum pit length have 0.5, 0.74, and 0.4 ${\mu}m$ respectively, the difference between the maximum and minimum value of the RF signal showed the greatest value. Also, we investigated RF signal in case of using an amplitude inversion mask, which transmitted regions are inversed against the conventional mask. The simulation results show that the better RF signal may be obtained by using an amplitude inversion mask.

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A New Method on the Nonlinear Distortion Analysis in the OFDM Communication System (OFDM 통신 시스템에서 비선형 왜곡분석의 새로운 분석기법)

  • 이동훈;정기호;유흥균
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.6
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    • pp.538-545
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    • 2002
  • In the orthogonal frequency division multiplexing (OFDM) system, the nonlinear distortion in the high power amplifier(HPA) degrades the system performance because of the high peak-to-average power ratio (PAPR). In this paper, a semi-analytical method is newly proposed for the performance evaluation of the nonlinearly distorted OFDM communication system. In the proposed method, at first, the probability density function (pdf) of the PAPR is generated by computer simulation. Then, mean and variance of the non-linear distortion noise process are computed. Next, the overall BER is found by the analytical method. When the equivalent SSPA model is applied in case of the QPSK/16-QAM and AWGN channel, the BER is calculated for the variation of the IBO(input back-off) and PAPR parameter. It is shown that the results by proposed method are very similar to those of the conventional Monte-Carlo method. The computation time can be considerably reduced than the conventional method that depends on the magnitudes of BER and IBO.

Effect of Latex and Mineral Additive on Durability of Remicon LMC (라텍스와 광물질 첨가제가 레미콘LMC (Remicon Latex Modified Concrete) 내구성에 미치는 영향)

  • Choi, So Yeong;Choi, Yoon Suk;Heo, Hyeong Seok;Yang, Eun Ik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.6
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    • pp.1743-1751
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    • 2014
  • It is well known that latex modification can lead to enhancement compressive and flexural performance, tensile bond strength, chloride penetration resistance and freezing-thawing resistance for concrete. For these, many studies for LMC pavement have been widely conducted more than those for conventional pavement concrete. However, due to several problems such as noise and construction cost, new approaches for LMC have been executed to improve the performance of LMC. Recently, Remicon LMC was developed in order to solve the problems of LMC. In this study, the durability of Remcion LMC was compared with latex and mineral additive mixing ratio. From the results, when latex and mineral additive were mixed in Remicon LMC, compressive, flexural and bond strength were satisfied with Korea Highway Construction Guide Specification. And, it showed that the qualitative effect of latex and mineral additive mixing ratio on the durability of Remicon LMC was investigated experimentally. Also, the latex mixed in Remicon LMC must be at least 8%, in order to ensure the durability equivalent or higher than conventional LMC.

Post Occupancy Evaluation for Office Building with An Underfloor Air Distribution System (바닥공조 시스템이 적용된 사무공간의 거주후 성능평가)

  • Yoon, Seong-Hoon;Jang, Hyang-In;Jung, Hae-Kwon;Choi, Sun-Kyu;Yu, Ki-Hyung
    • Journal of the Korean Solar Energy Society
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    • v.31 no.6
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    • pp.78-85
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    • 2011
  • In this study, an underfloor air distribution(UFAD) system installed on the S. office building was evaluated for its indoor environmental quality performance. Field measurement and survey were conducted for the overall POE(Post Occupied Evaluation). PMV(including temperature, humidity, air velocity and globe temperature) and several environmental components were measured while thermal comfort, thermal sensation, acoustical environment and others. were investigated through survey. Except for the direct upper part of the air supply diffuser on the floor, the indoor velocity was less than 0.25m/s, which has been suggested by ASHRAES tandard 55 as the limit for thermal comfort. MRT of the perimeter zone of the room showed a higher value than that in the interior because of the introduced solar radiation through the building envelope. PMV was generally maintained in the range of thermal comfort (from -0.5 to +0.5), though it weighted to the warm side. It was reported to have 61% positive response on thermal comfort and 55% on neutral thermal sensation. The results of each survey item showed some gender-based differences. Specifically, female respondents had higher degree of dissatisfaction with indoor air cleanness and acoustical privacy. The working surface showed more than 400 lux and the equivalent noise level showed less than 50 dB(A). In conclusion, the results of the measurement and survey showed good agreement. Indoor environmental quality of the subject office room where the UFAD system was installed showed an overall excellent performance.

Design and Analysis of a Battery Charge and Discharge Regulator of Communication Satellite (통신위성 배터리 충,방전기 설계 및 해석)

  • Choe,Jae-Dong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.7
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    • pp.118-126
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    • 2003
  • In this study, a battery charge and discharge regulator of modular type is designed as paralleled bi-directional converter that is possible to provide the power without failure not only in the steady state but also in the transient period by the step load variation or the unexpected faults among the converter modules. Each converter module is designed to get stability, performance, reliability, and maintainability and the average current mode method used for controller has the advantages such as noise immunity, fast response, and the real average current signal acquisition. The equivalent model and small signal model for the paralleled battery chargerIdischarger are presented, and also the transfer functions are analyzed for the CCM(Continuous Charge Mode), CDM(Continuous Discharge Mode) and DDM(Discontinuous Discharge Mode). The experiments of the paralleled bi-directional converter are carried out in the step load variation, and in faults of one converter module respectively. And the performance of paralleled bi-directional converter is verified via the experimental results.

Design of Domestic Induction Cooker based on Optimal Operation Class-E Inverter with Parallel Load Network under Large-Signal Excitation

  • Charoenwiangnuea, Patipong;Ekkaravarodome, Chainarin;Boonyaroonate, Itsda;Thounthong, Phatiphat;Jirasereeamornkul, Kamon
    • Journal of Power Electronics
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    • v.17 no.4
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    • pp.892-904
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    • 2017
  • A design of a Class-E inverter with only one inductor and one capacitor is presented. It is operated at the optimal operation mode for domestic cooker. The design principle is based on the zero-voltage derivative switching (ZVDS) of the Class-E inverter with a parallel load network, which is a parallel resonant equivalent circuit. An induction load characterization is obtained from a large-signal excitation test bench, which is the key to an accurate design of the induction cooker system. Consequently, the proposed scheme provides a more systematic, simple, accurate, and feasible solution than the conventional quasi-resonant inverter analysis based on series load network methodology. The derivative of the switch voltage is zero at the turn-on transition, and its absolute value is relatively small at the turn-off transition. Switching losses and noise are reduced. The parameters of the ZVDS Class-E inverter for the domestic induction cooker must be selected properly, and details of the design of the components of this Class-E inverter need to be addressed. A 1,200 W prototype is designed and evaluated to verify the validation of the proposed topology.