• Title/Summary/Keyword: low-IF

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Estimation of Ionospheric Delays in Dual Frequency Positioning - Future Possibility of Using Pseudo Range Measurements -

  • Isshiki, Hiroshi
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.2
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    • pp.185-190
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    • 2006
  • The correct estimation of the ionospheric delays is very important for the precise kinematic positioning especially in case of the long baseline. In case of triple frequency system, the ionospheric delays can be estimated from the measurements, but, in case of dual frequency system, the situation is not so simple. The precision of those supplied by the external information source such as IONEX is not sufficient. The high frequency component is neglected, and the precision of the low frequency component is not sufficient for the long baseline positioning. On the other hand, the high frequency component can be estimated from the phase range measurements. If the low frequency components are estimated by using the external information source or pseudo range measurements, a more reasonable estimation of the ionospheric delays may be possible. It has already been discussed by the author that the estimation of the low frequency components by using the external information source is not sufficient but fairly effective. The estimation using the pseudo range measurements is discussed in the present paper. The accuracy is not sufficient at present because of the errors in the pseudo range measurements. It is clarified that the bias errors in the pseudo range measurements are responsible for the poor accuracy of the ionospheric delays. However, if the accuracy of the pseudo range measurements is improved in future, the method would become very promising.

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The Impact of Servicescape on Customer Experience Quality through Employee-to-customer Interaction Quality and Peer-to-peer Interaction Quality in Hedonic Service Settings

  • Choi, Beomjoon;Kim, Hyun Sik
    • Asia Marketing Journal
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    • v.17 no.2
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    • pp.73-96
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    • 2015
  • This paper investigates how servicescape perception influences customer experience quality in hedonic service settings. In addition to the direct effect of servicescape quality on customer experience quality, the indirect effects of servicescape quality on customer experience quality via employee-to-customer interaction quality and peer-to-peer interaction quality are also investigated. We collected data through a self-administered survey. The proposed relationships were tested using structural equation modeling. The results show that servicescape quality influences customer experience quality both directly and indirectly through employee-to-customer interaction quality and peer-to-peer interaction quality, and customer experience quality influences customer loyalty. Additionally, we find that the indirect path via peer-to-peer interaction quality is significant only in a low-satisfaction customer group. The indirect effect of servicescape quality perception through peer-to-peer interaction quality is significant only in low-satisfaction customer groups. Therefore, if evaluations for this indirect effect fall below an acceptable level, it should be addressed first before improving on other attributes. However, after this point, further improvements offer few if any gains; therefore, service firms should allocate their resources to quality improvements to other factors. This study is the first to investigate the indirect effects of servicescape quality on customer experience quality via peer-to-peer interaction quality in hedonic service settings. Additionally, this study demonstrates that the significance of this indirect effect applies only to a low-satisfaction customer group.

A Study on the Improvement of Thermal Curing Performance of Concrete Using Hot Air Blower (열풍기 이용 콘크리트 보온양생 성능 개선 방안 분석)

  • Choi, Ji-Su;Kim, Sang-Yeop;Song, Jin-Hee;Cho, Hong-Beom;Rhee, Kyu-Nam
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2022.04a
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    • pp.239-240
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    • 2022
  • In winter, low outdoor temperature can casue reduction of concrete strength. Therefore, thermal protection is required when curing concrete in winter to maintain a certain level or higher surface temperature. Accordingly, in domestic construction sites, a curing method in which surrounds casting areas by tents and operates hot air blowers are widely applied. However, local low-temperature areas may occur due to airtightness of the curing tents. If additional heat is supplied to prevent occurrence of local low-temperature areas, energy consumption increases. Therefore in this study, a plan for improvement method of concrete curing was considered and the performance was evaluated through numerical analysis. A plan to improve the airtightness of the wall opening was applied, but the analysis showed that if only a part of the curing area is shielded, the temperature of the unshielded area decreases,making it inappropriate to improve curing performance.

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Clinical research of Bee-venom Acupuncture effects on Rheumatoid arthritis (봉약침을 이용한 류마토이드 관절염의 임상적 연구)

  • Hwang, Yoo-Jin;Lee, Geon-Mok;Hwang, Woo-Jun;Seo, Eun-Mi;Jang, Jong-Deok;Yang, Gui-Bi;Lee, Seung-Hoon;Lee, Byung-Chul
    • Journal of Acupuncture Research
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    • v.18 no.5
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    • pp.33-42
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    • 2001
  • Objective : To evaluate the effect of treatment for Rheumatoid arthritis by using Bee-venom Acupuncture that is well known for anti-inflammatory effect and function of activating immune system. Methods : Evaluated the result of Bee-venom Acupuncture treatment twice in a week for patients who diagnosised as rheumatoid arthritis by 7 criteria of US Rheumatism Academy. Results : 1. If you see the distribution chart, sexual rate of male and female was 1:2.75 and age distribution shows as age ascend it shows high. 2. If you see the duration distribution, it shows chronic tendency in order of more than 6 months (59.5%), 2 to 5 months, and 1 month. 3. If you see the invaded region distribution, it shows chronic tendency in order of finger(17 cases), wrist joint(16 cases), knee joint(16 cases), ankle joint(10 cases), elbow joint(8 cases), shoulder joint(7 cases), feet(7 cases), hip joint(5 cases), low back(3 cases) and neck(2 cases). 4. If you see the result of duration distribution treatment, the improvement index is rising in order of within a month, 2 to 5 months, and over 6 months. So it shows that it has good result of treatment within a month. 5. If you see the invaded region, it shows high improvement index in order of low back, hop joint, shoulder joint, wrist joint, feet, knee joint, finger, elbow joint, ankle joint and neck. 6. If you see the result of morning stiffness time before treatment, it shows good effect of treatment in order of 2-3hrs, 30min.-an hr, an hr to 2hrs, and 0-30min. 7. If you see the patients satisfaction after Bee-venom Acupuncture treatment, Excellent is 6 cases, Good is 7 cases, and Moderate 2 cases. Conclusions : It will have greater treatment effect if herbal medicine, moxibustion, and acupuncture are used together as patients whole body condition and symptoms with Bee-venom Acupuncture for rheumatoid arthritis that is chronic inflammatory disease.

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Measurement of Low-Frequency Ocean Noise by a Self-Recording Hydrophone (자동기록식 수중청음기를 이용한 저주파 해양잡음의 측정)

  • Kim, Bong-Chae;Kim, Byoung-Nam;Cho, Hong-Sang
    • Ocean and Polar Research
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    • v.29 no.4
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    • pp.311-316
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    • 2007
  • Ocean noise may be used for monitoring wind speed and rainfall rate on the sea surface, as well as for tracking whales' migration routes. In particular, low-frequency ocean noise has recently been of concern with relation to the behavior of marine mammals. Low-frequency ocean noise has been increasing over the past few decades due to increase of ship traffic and offshore oil industry activities. Mechanical noise such as flow noise and cable strumming noise may be induced if low-frequency ocean noise is measured by cabled traditional hydrophone in high current areas. To successfully measure low-frequency ocean noise in a shallow water environment with strong current, we developed a self-recording hydrophone. This paper describes the main configurations of the self-recording hydrophone and presents some results on measured data.

A Study on the English Vowel Lengths /$\ae$/, /c/, and /$\alpha$/ (영어모음 /$\ae$/, /c/, /$\alpha$/ 발음길이 연구)

  • Park, Hee-Suk
    • Speech Sciences
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    • v.8 no.4
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    • pp.215-220
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    • 2001
  • This study was done to find out the difference in vowel length between English produced by Americans and KATUSA soldiers. Though English pronunciation by Koreans shows different features in many ways, I focused on English vowel length of KATUSA soldiers. I wanted to know if English low vowels show a foreign accent by comparing vowel lengths in English produced by Americans and KATUSA soldiers. The reason I wanted to deal with English low vowels is that most Koreans have difficulty in pronouncing them. Therefore I selected three English low vowels, /$\{\ae}$, /c/, and/$\alpha$/, as the experimental object, and I tried to find out the foreign accent of them. In this study, I also tried to find out the vowel lengths in relation to their utterance positions and see the foreign accent of English low vowels. I investigated the difference of the English low vowels lengths between Americans and KATUSA soldiers using information gathered from experimental results.

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Improved RPV(reactive-power-variation) anti-islanding method for grid-connected three-phase PVPCS (3상 계통연계형 태양광 PCS의 단독운전검출을 위한 개선된 무효전력변동기법)

  • Lee, K.O.;Jung, Y.S.;So, J.H.;Yu, B.G.;Yu, G.J.;Choi, J.Y.;Choy, I.
    • Proceedings of the KIEE Conference
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    • 2006.07b
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    • pp.1159-1160
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    • 2006
  • As the grid-connected photovoltaic power conditioning systems (PVPCS) are installed in many residential areas, this has raised potential problems of network protection on electrical power system. One of the numerous problems is an Island phenomenon. There has been an argument that because the probability of islanding is extremely low it may be a non-issue in practice. However, there are three counter-arguments: First, the low probability of islanding is based on the assumption of 100% power matching between the PVPCS and the islanded local loads. In fact, an island can be easily formed even without 100% power matching (the power mismatch could be up to 30% if only traditional protections are used, e.g. under/over voltage/frequency). The 30% power-mismatch condition will drastically increase the islanding probability. Second, even with a larger power mismatch, the time for voltage or frequency to deviate sufficient to cause a trip, plus the time required to execute the trip (particularly if conventional switchgear is required to operate), can easily be greater than the typical re-close time on the distribution circuit. And, third, the low-probability argument is based on the study of PVPCS. Especially, if the output power of PVPCS equals to power consumption of local loads, it is very difficult for the PVPCS to sustain the voltage and frequency in an island. Unintentional islanding of PVPCS may result in power-quality issues, interference to grid-protection devices, equipment damage, and even personnel safety hazards. So the verification of anti-islanding performance is strongly needed. In this paper, the authors propose the improved RPV method through considering power quality and anti-islanding capacity of grid-connected three-phase PVPCS in IEEE Std 1547 ("Standard for Interconnecting Distributed Resources to Electric Power Systems"). And the simulation and experimental results are verified.

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The Effects of Sportswear Brands' Country-of-Origin on Purchase Intention in Terms of Brand Personality as Perceived by Chinese University Students (스포츠웨어 브랜드 원산지 이미지가 중국 대학생들의 브랜드 개성 지각과 구매의도에 미치는 영향)

  • Zhang, Fang-Fang;Kim, Yong-Sook
    • The Research Journal of the Costume Culture
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    • v.20 no.2
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    • pp.208-221
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    • 2012
  • The purpose of this study is to identify the effects of sportswear brands' country-of-origin on purchase intention (PI) in terms of brand personality as perceived by Chinese university students. Chinese students preferred to shop for sportswear at specialty stores, liked Nike and Adidas most, design was the most important factor when selecting, selected their sportswear themselves, and gathered information from TV ads. With regard to perceptions of brands country-of-origin, America was perceived as a developed country, influential to the world, but as having a bad relationship with China. Germany was perceived as a developed country and as having a well-developed civic culture, good people image, high technology, high influence on the world, and a good relationship with China. Italy was perceived as a developed country with the highest civic culture. China was perceived as a developing country, as having a good people image, and low technology and low influence on the world. Japan was perceived as a developed country with high technology. Factors of brand personality were sincerity, competence & sophistication, and excitement. Nike was perceived as having high competence & sophistication and excitement, Adidas as having high competence & sophistication and excitement, Lining as having high sincerity, and Mizuno's brand personality was very low. People image, competence & sophistication and excitement became higher, PI of Adidas increased. If people image, competence & sophistication and excitement became higher, PI of Kappa increased. If a country was developed and competence & sophistication and excitement became higher, PI of Lining increased. If civic culture, people image, technology, competence & sophistication and excitement became higher, PI of Mizuno increased.

An Assessment of the Heavy Metal Contamination of Sediment in Main Stream and Tributaries of the Han River in the Vicinity of Seoul (서울시 인근의 한강 본류 및 지류에 대한 하상 저질의 중금속오염 평가)

  • 노수미;이홍근
    • Journal of Environmental Health Sciences
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    • v.20 no.4
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    • pp.17-35
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    • 1994
  • This study was performed to investigate and assess the heavy metal contamination of sediment in main stream and tributaries of the Han-river in the vicinity of Seoul. Sediment were sampled at eight locations of main stream and eighteen locations of tributaries in the spring, summer, and fall in 1993. Six heavy metals of Cd, Cu, Pb, Zn, Cr, and Hg, were assessed. For an assessment of heavy metal contamination in sediment, the assessment method of Hakanson was modified to estimate for Han-river, then classification method of Muller in sediment quality was applied. For an assessment of contamination in each heavy metal, Contamination factor C$_f^i$ which was defined the ratio of concentration of i heavy metal in investigated location to background concentration of i heavy metal in uncontaminated upper area was used. The sediment quality in each heavymetal was classified as follows if C$_f^i$<1, Class I for Non contamination, if 1 < C$_f^i$ < 3, Class II for Low contamination, if 3< C$_f^i$ <6, Class III for Moderate contamination, if 6< C$_f^i$ <12, Class IV for Considerable contamination, and if C$_f^i$ > 12, Class V for High contamination.(abbreviation)

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W-band Single-chip Receiver MMIC for FMCW Radar (FMCW 레이더용 W-대역 단일칩 수신기 MMIC)

  • Lee, Seokchul;Kim, Youngmin;Lee, Sangho;Lee, Kihong;Kim, Wansik;Jeong, Jinho;Kwon, Youngwoo
    • Journal of the Institute of Electronics and Information Engineers
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    • v.49 no.10
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    • pp.159-168
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    • 2012
  • In this paper, a W-band single-chip receiver MMIC for FMCW(Frequency-modulated continuous-wave) radar is presented using $0.15{\mu}m$ GaAs pHEMT technology. The receiver MMIC consists of a 4-stage low noise amplifier(LNA), a down-converting mixer and a 3-stage LO buffer amplifier. The LNA is designed to exhibit a low noise figure and high linearity. A resistive mixer is adopted as a down-converting mixer in order to obtain high linearity and low noise performance at low IF. An additional LO buffer amplifier is also demonstrated to reduce the required LO power of the W-band mixer. The fabricated W-band single-chip receiver MMIC shows an excellent performance such as a conversion gain of 6.2 dB, a noise figure of 5.0 dB and input 1-dB compression point($P_{1dB,in}$) of -12.8 dBm, at the RF frequency of $f_0$ GHz, LO input power of -1 dBm and IF frequency of 100 MHz.