• Title/Summary/Keyword: RO

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Safety Evaluation of FO through Comparison of Boron Removal in Forward Osmosis(FO) and Reverse Osmosis(RO) (FO와 RO의 붕소 제거 비교를 통한 FO의 안정성 평가)

  • Kim, Chang-Woo;Lee, Sang-Youp;Hong, Seung-Kwan
    • 한국방재학회:학술대회논문집
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    • 2010.02a
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    • pp.101.2-101.2
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    • 2010
  • 현재 forward osmosis(FO)에 대한 관심이 증가하고 있다. 하지만 FO에 대한 안정성 평가는 전무한 실정이다. 본 연구는 많은 연구로 안정성을 인정받고 있는 RO와 직접 비교를 통하여 FO의 붕소에 대한 안정성을 평가하였다.

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On Deferred Statistical Convergence of Sequences

  • Kucukaslan, Mehme;Yilmazturk, Mujde
    • Kyungpook Mathematical Journal
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    • v.56 no.2
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    • pp.357-366
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    • 2016
  • In this paper, deferred statistical convergence is defined by using deferred $Ces{\grave{a}}ro$ mean instead of $Ces{\grave{a}}ro$ mean in the definition of statistical convergence. The obtained method is compared with strong deferred $Ces{\grave{a}}ro$ mean and statistical convergence under some certain assumptions. Also, some inclusion theorems and examples are given.

A Bibliographic Study About Heart Exhaustion (허로(虛勞)중 심로(心勞)의 원인(原因)과 증상(症狀)의 문헌적(文獻的) 고찰(考察))

  • Yoon, Ho-Seog
    • The Journal of Internal Korean Medicine
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    • v.12 no.1
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    • pp.68-76
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    • 1991
  • After studying 20 sorts of referance materials including Hwangjenaegyung which discuss the causes and symptoms of SymRo the researcher has been led to the following conclusions ; 1. In the reference materials, Hyulmakhuso (血脈虛少) is listed as the first potential cause of Sim Ro. Gokwoonsingi (曲運神機) is listed as the second potential cause. 2. Holholhemang (忽忽惠忘) is listed as the most obvious symptom of Sim Ro. Kunaesangchang (口內生瘡) is listed as the second obvious symptom.

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A Study of method to apply MANET Protocol for Route Optimization in Nested Mobile Network (Nested Mobile Network상의 Route Optimization을 위한 MANET Protocol 적용 방안 연구)

  • Choi, Seung-Won;Kim, Sang-Bok;Kim, Young-Beom
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.269-272
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    • 2005
  • 무선 네트워크 이동성 기술에 대한 연구가 수년간 진행되어 오면서 Mobile Network에 PAN(Personal Area Network)과 유사한 형태의 Nested Mobile Network에 대한 관심이 높아지고 있으며, 이러한 Nested Mobile Network에서의 경로최적화(Route Optimization : RO) 기술에 대한 연구가 활발하게 진행되고 있다. NEMO(NEtwork MObility)의 RO를 위해 제안된 논문 중에 ORC(Optimized Route Cache Protocol)에 대한 제안이 있었다.[1] NEMO Basic Support가 표준안으로 채택되면서 연구 대상에서 거론되지 않고 있지만, 복잡한 이동성 기술인 Nested Mobile Network상의 RO를 위해 다시 검토해 볼 수 있을 것이다. 또한 동일 저자에 의해 제안된 Nested Mobile Network 내부에 Ad-hoc Routing 알고리즘인 OLSR(Optimized Link State Routing Protocol)을 적용한 제안이 발표되었다.[2] 본 논문에서는 ORC와 Nested Mobile Network상의 OLSR Scheme을 적용하여 RO를 위한 방안을 제안하고자 한다.

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A study on boron removal for seawater desalination using the combination process of mineral cluster and RO membrane system

  • Cho, Bong-Yeon;Kim, Hye-Won;Shin, Yee-Sook
    • Environmental Engineering Research
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    • v.20 no.3
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    • pp.285-289
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    • 2015
  • Complicated and expensive seawater desalination technology is a big challenge in boron removal process. Conventional seawater desalination process of coagulation utilized for pre-treatment is difficult to remove boron. Boron can be removed more effectively in Reverse Osmosis (RO) process than any other processes. In this study, a coagulant with the name Mineral Cluster was examined its boron removal ability. Boron removal efficiency of Mineral Cluster depended on pH value and Mineral Cluster dosage. Desalination process combines the pre-treatment process with Mineral cluster diluted at the ratio of 1:2500 and the RO membrane process. The original sea water could be desalinated to drinking water quality, 1 mg/L, without any pH adjustments. Therefore, if the Mineral cluster is added without any other chemicals for adjusting pH, the desalination process would be much safer, efficient and economical.

Nonlinear Compensation Using Artificial Neural Network in Radio-over-Fiber System

  • Najarro, Andres Caceres;Kim, Sung-Man
    • Journal of information and communication convergence engineering
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    • v.16 no.1
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    • pp.1-5
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    • 2018
  • In radio-over-fiber (RoF) systems, nonlinear compensation is very important to meet the error vector magnitude (EVM) requirement of the mobile network standards. In this study, a nonlinear compensation technique based on an artificial neural network (ANN) is proposed for RoF systems. This technique is based on a backpropagation neural network (BPNN) with one hidden layer and three neuron units in this study. The BPNN obtains the inverse response of the system to compensate for nonlinearities. The EVM of the signal is measured by changing the number of neurons and the hidden layers in a RoF system modeled by a measured data. Based on our simulation results, it is concluded that one hidden layer and three neuron units are adequate for the RoF system. Our results showed that the EVMs were improved from 4.027% to 2.605% by using the proposed ANN compensator.

NCURO DATA RETRIEVAL ALGORITHM IN FORMOSAT-3 GPS RADIO OCCULTATION OBSERVATION OF GRAVITY WAVE ACTIVITY

  • Yeh, Wen-Hao;Chiu, Tsen-Chieh;Liou, Yuei-An;Yan, Shian-Kun;Huang, Cheng-Yung
    • Proceedings of the KSRS Conference
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    • 2008.10a
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    • pp.192-195
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    • 2008
  • Radio occultation (RO) has been used in the planetary science since Microlab-1 was launched in 1995. With the RO technique, the profiles of atmosphere and the global atmospheric data can be obtained. In 2006, Taiwan launched six low Earth orbit (LEO) satellites as the RO constellation mission, known as FORMOSAT-3. In order to retrieve the RO data from original data, a retrieval algorithm, NCURO, is developed. The input of NCURO algorithm is mainly the excess phase of GPS signal, and the output is the dry pressure and dry temperature. Using temperature profiles retrieved by NCURO algorithm, temperature perturbation and potential energy of gravity wave have been evaluated. In this paper, the retrieval algorithm and the global distribution of energy of gravity waves are described and demonstrated.

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Combined Effects of Metal Coagulants and Monochloramine on Polyamide RO Membrane Performance (금속성 응집제와 모노클로라민의 상호작용이 Polyamide계 RO막 성능에 미치는 영향)

  • Kim, Kyunghwa;Hong, Seungkwan;Park, Chanhyuk;Yoon, Seongro;Hong, Seongpyuo;Lee, Jonghwa
    • Journal of Korean Society of Water and Wastewater
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    • v.20 no.4
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    • pp.637-643
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    • 2006
  • The bench-scale chlorine exposure study was performed to investigate the effect of pretreatment by free chlorine and monochloramine ($NH_2Cl$) on the performance of RO membranes made of polyamide (PA). Feed monochloramination at 2mg/L did not cause significant productivity loss compared to free chlorine. However, metal coagulants reacted with monochloramine, the PA membrane suffered from a gradual loss of membrane integrity by chlorine oxidation, which was characterized as a decrease in salt rejection. Especially, RO membranes exposed to alum coagulants with monochloramine revealed the salt rejection lower than those exposed to iron coagulants. XPS membrane surface analysis demonstrated that the chlorine uptake on the membrane surface increased and carbon peaks were shifted significantly when exposed to alum coagulants with monochloramine.

Removal of boron in seawater by activated carbon adsoprtion (활성탄 흡착에 의한 해수중의 보론 제거)

  • Kim, Han-Seung;Kang, Joon-Seok;Kim, Byung-Ro
    • Journal of Korean Society of Water and Wastewater
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    • v.25 no.6
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    • pp.917-922
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    • 2011
  • Adsorption characteristics of boron on activated carbon was investigated in order to evaluate the use of activated carbon for the removal of boron in desalination processes using SWRO. Boron was removed ranging from 54~60% when the concentration of activated carbon was 1,000 mg/L in 6 hours under the initial boron concentration of 5 mg/L. The removal of boron increased by 20~22% with the increase of pH from 5 to 9. Organic matter had adverse effect on the adsorption of boron on activated carbon. Boron removal decreased by 10-12% when EDTA was added at 1 mg/L under 5 mg/L of boron and 200mg/L of activated carbon. In this results, activated carbon would be a good candidate for a pretreatment of desalination processes by SWRO from the view of mitigating the feed boron concentration to RO and meeting the effluent boron concentration without post-treatment after RO.

Open Loop Technique in FORMOSAT-3/COSMIC mission

  • Yeh, Wen-Hao;Chiu, Tsen-Chieh;Liou, Yuei-An;Huang, Cheng-Yung
    • Proceedings of the KSRS Conference
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    • 2007.10a
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    • pp.394-396
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    • 2007
  • Radio occultation (RO) technique has been used in planetary science since 1960s. When signal goes through atmosphere, it is refracted due to the gradient of atmospheric refractivity. In 1995, the first low earth orbit (LEO) satellite, MicroLab-1, was launched to conduct RO mission. It receives the signal from global positioning system (GPS) satellites. After MicroLab-1, other RO missions, such as CHAMP, SAC-C, and GRACE, are executed in several years later. In 2006, Taiwan launched six LEO satellites for RO mission. The mission name is Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC). Under some abnormal situations, multipath and strong fluctuation in phase and amplitude of the signal appear in moist troposphere. Therefore, open loop (OL) technique has been applied to replace traditional phase lock loop (PLL) technique. In this paper, we will summarize the retrieval processing procedure and discuss the advantages and disadvantages of OL technique.

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