• Title/Summary/Keyword: Low-altitude

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Development of High Speed Low Noise frequency Synthesize for Low Altitude Surveillance Radar (저고도 탐지레이다용 고속 저잡음 주파수합성기 개발에 관한 연구)

  • Yoon, In-Chul;Kim, Hie-Sik
    • Proceedings of the IEEK Conference
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    • 2009.05a
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    • pp.252-254
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    • 2009
  • 본 논문에서는 저고도 탐지레이다 센서체계의 주파수 합성기는 송수신 장치의 기준 주파수원으로 이용될 국부 발진 주파수들을 생성해 내는 주파수 합성부에 대해 설명되었다. 주파수 합성기의 성능을 평가하기위하여 각 주파수 원들의 위상잡음 특성과 주파수 합성기의 스위칭 시간을 신호 혼합기를 이용하여 측정 하였으며, 그 결과 설계 시 제시한 30(usec)이하인 약18usec의 스위칭 시간이 대부분을 차지함을 알 수 있었다. 주파수 합성기에서 생성된 최종 출력 주파수는 저고도 탐지 레이다의 송수신 장치의 국부발진 주파수로 이용되므로 출력 레벨의 flatness를 측정하여 분석한다.

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The Design and Construction Consideration for Developing the Human Powered Aircraft (인력비행기 개발을 위한 설계 및 제작 고려 요소)

  • Lee, Ki-Young;Choi, Seong-Ok
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.17 no.1
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    • pp.29-38
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    • 2009
  • This paper surveys the historical perspective and design considerations for developing the human powered aircraft(HPA). Especially the weight and materials, aerodynamics, flight controls, and power trains are focused. The average power a human can produce and sustain is approximately 200${\sim}$250 W which is a critical design constraint of HPA. The survey shows that the empty weight of HPA was in the 30${\sim}$40 kg range(90${\sim}$110 kg include pilot). Thus, in order to design a successful HPA, the value of power to weight ratio should be 2.0 W/kg or above. The HPA design technique could be applied directly to the development of an unmanned high altitude airplanes used for atmospheric research, where light structures, low Reynolds number aerodynamics and high efficiency propeller design are required as well.

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Design of the Low Energy Electron Detector for DITSAT-B

  • Park, Young-Wan-;Min, Kyoung-Wook
    • Bulletin of the Korean Space Science Society
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    • 1993.10a
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    • pp.22-22
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    • 1993
  • We developed the low energy electron detector (LEED) for KITSAT-B which was launched on September 26, 1998. The sensor head is mounted on the top of the satellite so that it can measure the precipitating electron flux along the Magnetic field line in the auroral zone at 820 km altitude. The detector system is composed of 4 parts : the electrostatic analyzer, the spira10on detector, the discriminator / Preamplifier, and the interface to the spacecraft. The analyzer limits the access to the spiraltron only to the electrons of certain energies which are determined by the electrostatic field across the two coaxial cylindrical analyzer plates. The energy spectrum of the detector in consideration is about 100 eV to 6.7 KeV, which is swept in 1.6 seconds and divided into 16 bins. It 81so is 1.6 second reset period after each swept, We will discuss the technical features of the system as well as the future observational schedule.

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OPTICAL PROPERTIES OF ASIAN DUST AEROSOL DERIVED FROM SEAWIFS AND LIDAR OBSERVATIONS: A CASE STUDY OF DUST OVER CLOUDS

  • Fukushima, H.;Kobayashi, H.;Murayama, T.;Ohta, S.;Uno, I.
    • Proceedings of the KSRS Conference
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    • 2002.10a
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    • pp.367-372
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    • 2002
  • Asian dust aerosol layer of 4-6 km altitude accompanied by low clouds was observed by LIDAR and sky-radiometer in Tokyo urban area on April 10, 2001. To synthesize the top of atmosphere (TOA) reflectance, radiative transfer simulation conducted assuming aerosol/cloud vertical structure and aerosol size distribution that were modeled after the ground observations. The refractive index of Asian dust is derived from a laboratory measurement of sampled Chinese soil particles. The synthesized TOA reflectance is compared to the SeaWiFS-derived one sampled at the low cloud pixels whose airmass is the same as the one passed at the observation site. While the two TOA reflectances compare generally well with few percent difference in reflectance, possible sources of the discrepancy are discussed.

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Illumination Variations in Near-Equatorial Orbit Imaging: A Case Study with Simulated Data of RAZAKSAT

  • Hassan, Aida-Hayati-Mohd;Hashim, Mazlan;Arshad, Ahmad-Sabirin
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.1052-1054
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    • 2003
  • RAZAKSAT is a second micro-satellite mission by Malaysian Satellite Program and is expected for launch in June 2004. Designed to orbit the earth at low-equatorial orbit, RAZAKSAT will meet Malaysia’s immediate needs to rapid data acquisition (real time and more repetitions) to address many operational issues of remote sensing applications, which require availability of current data sets. RAZAKSAT will be among the first remote sensing satellite to orbit the earth at low inclination along the equator, 9$^{\circ}$ with 685km altitude, hence, allows optimal geographical information and environment change within equatorial region be observed with a unique revisit characteristics. The satellite primary payload is MAC, a push-broom type camera with 2.5m of ground sampling distance (GSD) in panchromatic band and 5m of GSD in four multi-spectral bands. This paper describes on the variation of illumination anticipated from simulated RAZAKSAT image, examine its implication to its ground leaving radiances for major applications.

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Japanese Apricot in Taiwan (대만의 매실산업)

  • Li, Kuo-Tan
    • Food Science and Industry
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    • v.45 no.2
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    • pp.29-35
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    • 2012
  • Japanese apricot (Prunus mume Sieb. et Zucc.) is the national symbol and was once the most important temperate fruit crop in Taiwan. Fruiting cultivars were originally introduced from southern China but commercial production was not significant until the 1970s. Currently 6,400 ha of Japanese apricot orchards distribute on shallow mountain hills in the central and the southern part of the island. Taiwanese commercial fruiting cultivars are plausibly chance seedlings or sports from the early introduction and are very low chilling required for budbreak. Ornamental cultivars have been mainly introduced from Japan but cultivations have been limited in high altitude area due to their high chilling requirement. In 2009, Taiwan Agricultural Research Institute's breeding program released the first low chill ornamental cultivar 'Tainung No.2' with a great ornamental potential in subtropical regions. Cultivation and production of Japanese apricot fruit in Taiwan continue to dwindle due to the declining Japanese market share. Ongoing industry transformation to increase domestic consumption and consumer's interest will sustain the future of Japanese apricot in Taiwan.

Machine Learning-Based Filter Parameter Estimation for Inertial/Altitude Sensor Fusion (관성/고도 센서 융합을 위한 기계학습 기반 필터 파라미터 추정)

  • Hyeon-su Hwang;Hyo-jung Kim;Hak-tae Lee;Jong-han Kim
    • Journal of Advanced Navigation Technology
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    • v.27 no.6
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    • pp.884-887
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    • 2023
  • Recently, research has been actively conducted to overcome the limitations of high-priced single sensors and reduce costs through the convergence of low-cost multi-variable sensors. This paper estimates state variables through asynchronous Kalman filters constructed using CVXPY and uses Cvxpylayers to compare and learn state variables estimated from CVXPY with true value data to estimate filter parameters of low-cost sensors fusion.

The internet perceived risk segments: clothing benefits sought, internet shopping attitude, and internet purchase intention (인터넷 위험지각 집단의 의복추구혜택, 인터넷 쇼핑태도 및 구매의도)

  • 황진숙
    • Journal of the Korean Society of Clothing and Textiles
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    • v.27 no.7
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    • pp.746-757
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    • 2003
  • The purpose of this study was to investigate the internet perceived risk segments in regard to clothing benefits sought, internet shopping attitude, and internet purchase intention. The subjects used for the study were 210 male and 338 female college students. The internet perceived risk consisted of size/defect risk, social psychological risk, privacy risk, delivery risk, and price risk. The clothing benefits sought had impression improvement, fashion, individuality, figure flaws compensation, and comfort factors. The results showed that consumers were segmented by four groups based on internet perceived risk factors : 1) privacy risk group, 2) size risk group. 3) low risk group, and 4) price/social psychological risk group. The four segmented groups differed in regard to clothing benefits sought, internet shopping attitude, and internet purchase intention. For example, in regard to clothing benefits sought, the price/social Psychological risk group sought fashion more than other groups. The low risk group considered figure flaws compensation benefit less important than other groups. Concerning internet shopping attitude, the low risk group had more favorable altitude toward trust, safety, diversity, exchange/return attributes of internet shopping than other groups. The privacy risk group had more favorable attitude toward convenience and price attributes of internet shopping. Regarding internet purchase intention, the low risk group had higher intention to purchase formal, casual, and sportswear. The size risk group had higher intention to purchase fashion accessories. Further group differences and implications of the results were discussed.

Mapping quantitative trait loci controlling low-temperature germinability in rice

  • Nguyen, Hoang Nam;Park, In-Kyu;Yeo, Sang-Min;Yun, Yeo-Tae;Ahn, Sang-Nag
    • Korean Journal of Agricultural Science
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    • v.39 no.4
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    • pp.477-482
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    • 2012
  • Low-temperature germination is one of the major determinants for stable stand establishment in the rice direct seeding method in temperate regions and at high altitude areas. Quantitative trait loci (QTL) controlling low-temperature germinability in rice were identified using 96 introgression lines (ILs) derived from a cross between Oryza rufipogon and the Korean japonica cultivar, 'Hwaseongbyeo'. The germination rate at $15^{\circ}C$ was measured to represent low-temperature germination and used for QTL analysis. The germination rate at $15^{\circ}C$ for 7 days of Oryza rufipogon and Hwaseongbyeo was 93.3 and 28.7%, respectively, and that of progenies ranged from 0 to 48%. A linkage map was constructed using 135 simple sequence repeat (SSR) markers. Five putative QTLs associated with low-temperature germination were detected on chromosomes 1, 3, 4, 10 and 11. The QTL, qltg10 on chromosome 10 accounted for 19.2% of the total phenotypic variation for low-temperature germinability. Four additional QTL, accounted for 10.4 - 15.1% of the total phenotypic variation. The O. rufipogon alleles in all detected QTLs loci increased the low-temperature germination rate. No QTL associated with low temperature germinability has been detected near the qltg10 QTL in this study suggesting that qltg10 is a new QTL. The locus, qltg10 is of particular interest because of its independence from undesirable height and maturity effects. The DNA markers linked to the QTL for low temperature germinability would be useful in selecting lines with enhanced low temperature germinability in rice breeding program.

An Empirical Study on Emotional Intensity and the Influence of Product Involvement in the Context of the Integrative Framework

  • Pradip Hira, Sadarangani;Sanjaya S., Gaur
    • Journal of Global Scholars of Marketing Science
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    • v.12
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    • pp.99-119
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    • 2003
  • A model is proposed for the role of emotional intensity of a web site, and the moderating influence of product involvement, in the Integrative Framework of persuasion (Meyers-Levy and Malvaiya 1999). The model also appropriately operationalizes the constructs emotional intensity of a web site and product involvement The three routes to persuasion, Central, Peripheral, and Experiential correspond to high, moderate, and low involvement (Meyers-Levy and Malaviya 1999). The involvement construct is measured from message recipients using the Personal Product Inventory (Pill, which was developed to capture the concept of product involvement (Zaichkowsky 1985). The conceptualization of the Personal Product Inventory is a contextrree measure that also has robust psychometric properties when applied to advertisements (Zaichkowsky 1994). The propositions highlight the expected importance of emotional intensity of a web site. The moderating influence of product involvement is also proposed. Specifically, what this work proposes is that the emotional intensity of a product site has a larger impact on attitude change under low product involvement, as opposed to moderate product involvement. Support for this reasoning can be found in the persuasion literature (Petty et al 1986). The Petty et al (1986) frame work is a dual process descriptive and predictive frame work in the area of altitude formation and change. Recently, Myers Levy and Malaviya (1999) have proposed a tri-process framework. This is in tum based on the dual process model of Petty et al. (1986). The study outlined in this paper aims to deepen the Meyers Levy and Malaviya (1999) and frame work. The propositions outlined in the model are empirically tested using a repeated measures experimental design. The emotional intensity is measured using a scale that is based on experts judgments. Using a paired comparison t-test two sites are determined to be of high and low emotional intensity. The model is tested using a repeated measures experimental design. The first independent variable Emotional Intensity of the site is manipulated. The Second independent variable, Personal Product Inventory is measured. While, the dependent variable, product altitude change will also be measured. Utilizing Analysis of Variance (ANOVA) the data is analyzed using SPSS. The results suggest that besides the rational content of messages their emotional content can also influence attitude change. Specifically, it is proposed that the manipulation of emotional intensity of a product Web site has a greater impact on product altitudes under high and low product involvement conditions, rather than moderate product involvement. However, the results for product involvement as a continuous variable has a p value of 0.09. Further, the results for three levels of product involvement were far from significant. For two levels of product involvement also, the results were insignificant, the p value approached 0.20. This evidence indicates that it is premature to conclude that there are three routes to persuasion. A caveat, however, must be added, in that the manipulations may not have been strong enough to test the proposed hypotheses. Further, undoubtedly, there is unequivocal evidence the emotional intensity of a product Web site, as measured here, has a direct impact on product attitudes.

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