• Title/Summary/Keyword: frequency measurement

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Science Objectives and Design of Ionospheric Monitoring Instrument Ionospheric Anomaly Monitoring by Magnetometer And Plasma-probe (IAMMAP) for the CAS500-3 Satellite

  • Ryu, Kwangsun;Lee, Seunguk;Woo, Chang Ho;Lee, Junchan;Jang, Eunjin;Hwang, Jaemin;Kim, Jin-Kyu;Cha, Wonho;Kim, Dong-guk;Koo, BonJu;Park, SeongOg;Choi, Dooyoung;Choi, Cheong Rim
    • Journal of Astronomy and Space Sciences
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    • v.39 no.3
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    • pp.117-126
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    • 2022
  • The Ionospheric Anomaly Monitoring by Magnetometer And Plasma-probe (IAMMAP) is one of the scientific instruments for the Compact Advanced Satellite 500-3 (CAS 500-3) which is planned to be launched by Korean Space Launch Vehicle in 2024. The main scientific objective of IAMMAP is to understand the complicated correlation between the equatorial electro-jet (EEJ) and the equatorial ionization anomaly (EIA) which play important roles in the dynamics of the ionospheric plasma in the dayside equator region. IAMMAP consists of an impedance probe (IP) for precise plasma measurement and magnetometers for EEJ current estimation. The designated sun-synchronous orbit along the quasi-meridional plane makes the instrument suitable for studying the EIA and EEJ. The newly-devised IP is expected to obtain the electron density of the ionosphere with unprecedented precision by measuring the upper-hybrid frequency (fUHR) of the ionospheric plasma, which is not affected by the satellite geometry, the spacecraft potential, or contamination unlike conventional Langmuir probes. A set of temperature-tolerant precision fluxgate magnetometers, called Adaptive In-phase MAGnetometer, is employed also for studying the complicated current system in the ionosphere and magnetosphere, which is particularly related with the EEJ caused by the potential difference along the zonal direction.

The development of the photoreflectance program for the analysis of semiconductor optical properties

  • Shin, Sang-Hoon;Kim, Geun-Hyeong
    • Journal of the Korea Society of Computer and Information
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    • v.27 no.8
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    • pp.211-218
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    • 2022
  • In this paper, a computer simulation program was developed to interpret the results measured by photoreflectance spectroscopy. The developed program is implemented so that the user can easily change the factors required for optical modulation characteristic interpretation, and the result of the value can be checked simultaneously with the actual measurement result. The results obtained by photoreflectance spectroscopy are obtained by mixing a third derivative function form (TDFF) modulated around a bandgap with a Franz-Keldysh oscillation (FKO) signal due to an electric field at a surface and an interface higher than the bandgap. Through the computer simulation program, the optical characteristics that appear in the GaSb Epi layer formed as a single layer were analyzed, and very useful results were obtained by specializing in optical modulation analysis. In addition, a Fast Fourier Transform (FFT) analysis tool was added to facilitate frequency characteristics analysis of FKO.

Surgical importance of the tympanic bone: multidetector computed tomography findings

  • Atlanoglu, Sahinde;Topuz, Muhammed Fatih
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.48 no.3
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    • pp.149-154
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    • 2022
  • Objectives: To measure tympanic bone thickness (anterior-superior, anterior-inferior, and inferior wall), external ear canal length, and tympanomandibular distance that can be useful in cases that undergo tympanic bone resection. Materials and Methods: The temporal computed tomography (CT) images of 349 patients were retrospectively evaluated. The anterior-inferior, anterior-superior, and inferior wall thicknesses; tympanomandibular distance; and external auditory canal (EAC) bone canal length were measured from the narrowest part of the canal. The shapes of the EAC in the coronal and sagittal planes were also examined. Results: The numbers of female and male patients were similar, and the mean age was 49.45±13.95 years. The anterior-superior, anterior-inferior, and inferior wall thicknesses were 1.92±0.60, 2.54±0.74, and 9.16±2.20 mm, respectively. The anterior-superior and anterior-inferior wall thicknesses and canal lengths were greater on the right side (P<0.001). All measurement values were higher in males, except right tympanomandibular distance (P<0.05). A non-significant negative correlation was found between the age of the participants and the left anterior-inferior wall and tympanomandibular distance on both sides. Intra-observer agreement was high for all measurements. We observed four main shapes in the external ear canal in the coronal plane: Type 3, Type 2, Type 1, and Type 4 in order of frequency on the right, and Type 2, Type 3, Type 1, and Type 4 on the left. In the sagittal plane, we detected three shapes: oval (74.4%), triangular (16.3%), and round (9.4%). Conclusion: The anterior wall thicknesses and tympanomandibular distance should be measured on preoperative temporal bone CT to safely perform tympanic bone anterior resection, which is required in some otological procedures, and also to prevent temporomandibular joint damage.

Development of the ICF/KCF code set the people with Nervous System Disease: Based on Physical Therapy (신경계 환자 평가를 위한 ICF/KCF 코드세트 개발: 물리치료 중심으로)

  • Ju-Min Song;Sun-Wook Park
    • Journal of the Korean Society of Physical Medicine
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    • v.18 no.1
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    • pp.99-110
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    • 2023
  • PURPOSE: This study was conducted to suggest a way to easily understand and utilize the International Classification of Functioning, Disability and Health (ICF) or Korean Standard Classification of Functioning, Disability and Health (KCF), a common and standard language related to health information. METHODS: The tools used by physical therapists to evaluate the functioning of neurological patients were collected from 10 domestic hospitals. By applying the ICF linking rule, two experts compared, analyzed, and linked the concepts in the items of the collected tools and the ICF/KCF codes. The frequency of use of the selected tool, the matching rate of the liking results of two experts, and the number of the codes linked were treated as descriptive statistics and the code set was presented as a list. RESULTS: The berg balance scale, trunk impairment scale, timed up and go test, functional ambulation category, 6 Minute walk test, manual muscle test, and range of motion measurements were the most commonly used tools for evaluating the functioning. The total number of items of the seven tools was 33, and the codes linked to the ICF/KCF were 69. Twenty-two codes were mapped, excluding duplicate codes. Ten codes in the body function, 11 codes in the activity, and one code in the environmental factor were included. CONCLUSION: The information on the development process of the code set will increase the understanding of ICF/KCF and the developed code set can conveniently be used for collecting patients' functioning information.

VSimulators: A New UK-based Immersive Experimental Facility for Studying Occupant Response to Wind-induced Motion of Tall Buildings

  • Antony Darby;James Brownjohn;Erfan Shahabpoor;Kaveh Heshmati
    • International Journal of High-Rise Buildings
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    • v.11 no.4
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    • pp.347-362
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    • 2022
  • Current vibration serviceability assessment criteria for wind-induced vibrations in tall buildings are based largely on human 'perception' thresholds which are shown not to be directly translatable to human 'acceptability' of vibrations. There is also a considerable debate about both the metrics and criteria for vibration acceptability, such as frequency of occurrence or peak vs mean vibration, and how these might vary with the nature of the vibration. Furthermore, the design criteria are necessarily simplified for ease of application so cannot account for a range of environmental, situational and human factors that may enhance or diminish the impact of vibrations on serviceability. The dual-site VSimulators facility was created specifically to provide an experimental platform to address gaps in understanding of human response to building vibration. This paper considers how VSimulators can be used to inform general design guidance and support design of specific buildings for habitability, in terms of vibration, which allow engineers and clients to make informed decisions with regard to sustainable design, in terms of energy and financial cost. This paper first provides a brief overview of current vibration serviceability assessment guidelines, and the current understanding and limitations of occupants' acceptability of wind-induced motion in tall buildings. It then describes how the dual-site VSimulators facility at the Universities of Bath and Exeter can be used to assess the effects of motion and environment on human comfort, wellbeing and productivity with examples of how the facility capabilities have been used to provide new, human experience based experimental research approaches.

Improving soil moisture accuracy in ungauged areas using Multi-Satellite data (다종위성에 근거한 미계측 지역의 토양수분 정확도 향상에 관한 연구)

  • Doyoung Kim;Hyunho Jeon;Seulchan Lee;Minha Choi
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.433-433
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    • 2023
  • 토양수분은 물 순환의 필수적인 요소로써 수문순환 및 기상 현상에 큰 영향을 미친다. 현재 우리나라에서는 토양수분 자료구축을 위해 Frequency Domain Reflectometry (FDR), Time Domain Reflectometry (TDR) 센서를 활용하여 지점 단위 토양수분 자료를 생산하고 있다. 그러나 한반도는 도서, 산간 지역이 다수 분포하고 있어, 지점관측 센서만으로 공간 대표성을 갖는 토양수분 자료를 산출하기 어렵다. 이에, 광범위한 지역을 장기간 모니터링 할 수 있는 원격탐사 기법을 활용하여, Advanced SCATterometer (ASCAT), Soil Moisture Active and Passive (SMAP) 등의 공간 단위 토양수분 자료의 적용성이 평가되고 있다. 하지만, 공간 토양수분 자료의 검증을 위해 필수적인 지점 토양수분 자료가 구축되지 않은 미계측지역이 다수 존재하며, 한반도와 같이 지형적 복잡성이 높게 나타나는 지역에서는 계측지역에서의 활용성 평가 결과가 미계측지역에서도 유사하게 나타난다고 가정하기 어렵다. 이에 본 연구에서는, 미계측지역의 공간 토양수분 자료를 산출하고자 계측지역에서 SM2RAIN 알고리즘으로 산출된 강수량 자료와 위성 산출 자료 그리고 지점관측 자료의 관계성을 분석했다. SM2RAIN 알고리즘의 입력자료는 Advanced SCATterometer (ASCAT) 토양수분 자료를 활용했다. ASCAT 토양수분 자료와 SM2RAIN 강수 자료의 검증을 위해 기상청에서 제공하는 Automated Agriculture Observing System (AAOS) 토양수분 자료, Automatic Weather System (AWS) 강수량 자료와 Global Precipitation Measurement (GPM) 강수 자료를 활용하였다. 전반적으로 ASCAT 토양수분을 통해 산출한 SM2RAIN 강수량의 추정과GPM 강수량이 유의미한 상관성이 나타나는 것을 확인할 수 있었으며, 추후 Downscaling 기법과 연계하여 지형적 복잡성이 높게 나타나는 지역의 토양수분 추정이 가능할 것으로 기대된다.

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Characteristic Verification of Electronically Scanned Array Antenna for a Ku-band FMCW Radar (Ku-대역 FMCW 레이더용 전자식 빔 조향 배열 안테나 특성 검증)

  • Chae-Hyun Jung;Jaemin Lee;Minchul Kim;Hang-Soo Lee;Sungjun Yoo;Sunghoon Jang
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.23 no.4
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    • pp.65-71
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    • 2023
  • In this paper, the design, fabrication and verification steps of an electronically scanned array antenna(AESA) for a photonics-based Ku-band FMCW radar system is described. The presented system consists of a transmitter and a receiver respectively, which has a same antenna in the transceiver. The designed antenna has 2×8 array configuration and operates at Ku-band. The VSWR(Voltage Standing Wave Ratio) of each 16-radiators and the coupling power between radiators is measured. Also, in order to minimize the radar system damage because of handover power from the transmitter antenna to the receiver antenna when the transmitter works, the isolation between the transmitter antenna and the receiver antenna is optimized by test. As a result, beamwidth, side lobe level and beam steering characteristic are obtained by synthesizing each radiator pattern measurement data after each beam pattern of 16-radiators is measured in the near-field chamber.

A Study of the C-band Ground-based Radio Navigation System for UAM Cooperative Navigation (UAM 복합 항법을 위한 C 밴드 지상기반 전파 항법 시스템 연구)

  • Kyung-Soon Lee;Yong-Un Cho;Min-Jung Kim;Kyung Heon, Koo
    • Journal of Advanced Navigation Technology
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    • v.27 no.4
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    • pp.374-381
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    • 2023
  • This study focuses on the implementation of C-band radio navigation in the 5.03 ~ 5.15 GHz terrestrial band to cooperate with GNSS navigation mainly used in existing UAMs. This is one of the navigation technologies that can fully satisfy the requirements of Title 14 of CFR-135.165. According to the FAA, the use of two or more independent navigation sources for aircraft is proposed for aircraft. This study proceeded with the link budget derivation through radio wave propagation path loss analysis, and antenna shape design for miniaturized Doppler VOR, and DME design with enhanced positional distance resolution compared to conventional aircraft. The ground navigation system which is the result of this study, consists of a VOR/DME ground station and a terminal that can be mounted on UAM. Significant performance was confirmed through the production and testing of each prototype.

Changes in the visual display terminal syndrome of college students in online classes during the COVID-19 pandemic (COVID-19 팬데믹 상황에서 온라인 수업 중인 대학생의 영상표시단말기 증후군의 변화)

  • Jang, Keong Sook;Jung, Young-Mi
    • The Journal of Korean Academic Society of Nursing Education
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    • v.29 no.1
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    • pp.60-71
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    • 2023
  • Purpose: The purpose of this study was to identify changes in the experience rate and level of symptoms of visual display terminal syndrome in college students attending online classes during the COVID-19 pandemic. Methods: Data were collected from February 22 to June 8, 2021 at three measurement points. A total of 117 college students were administered a visual display terminal syndrome survey just before online classes (T1), one month after the start of online classes (T2), and three months after the start of online classes (T3). The collected data were analyzed by frequency and percentage, paired t-test, McNemar test, and repeated measures analysis of variance using the IBM SPSS 25.0 program. Results: The intensity of college students' visual display terminal syndrome during online classes increased at T2 and T3 compared to T1. The rate of experiencing back discomfort or pain increased abruptly at T2 compared to T1. The intensity of college students' eye related symptoms and skin related symptoms increased at T2 and T3 compared to T1, while the intensity of college students' psychological symptoms, general body discomfort, and musculoskeletal symptoms increased at T3 compared to T1. Conclusion: The results of this study suggest that self-care programs are needed to prevent visual display terminal syndrome in college students who are in long-term online classes.

A narrative review of clinical studies on thread embedding acupuncture treatment for spasticity after stroke

  • Sooran Cho;Eunseok Kim
    • The Journal of Korean Medicine
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    • v.43 no.4
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    • pp.131-144
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    • 2022
  • Objectives: This study aimed to review clinical studies on thread embedding acupuncture (TEA) for the treatment of patients with post-stroke spasticity (PSS) Methods: Clinical studies related to TEA treatment for PSS were searched for in several electronic databases, including PubMed, Cochrane Library, MEDLINE, OASIS, and CNKI. After the selection/exclusion process, information on study design, disease, experimental/control group, intervention, outcome measurement, between-group differences, and adverse events was extracted. Results: A total of 13 randomized controlled trials were included in this review. The usual frequency of TEA treatment was once every 1-2 weeks, and the treatment most commonly included 4 sessions. In the dorsal area, EX-B2 and the acupoints in governing vessel meridian were commonly used. Acupoints in the meridian of the large intestine were most frequently used in the treatment of upper limb spasticity. Except for HT1, PC6, and PC8, all TEA points for treating PSS of the upper limb were on the Yang meridians. For the lower limb spasticity, the most frequently used acupoints were ST36, GB34, GB30, BL60, and BL57 on Yang meridians, and LR3, SP6, SP9, and SP10 on Yin meridians. TEA treatment showed better effects than conventional treatment for PSS in terms of spasticity, motor dysfunction, and activities of daily livings. Nevertheless, the absence of the follow-up observation, lack of sham TEA treatment, and low quality of the included studies necessitated caution in interpreting the results. Conclusions: The results of this review are expected to provide basic data on the modalities of TEA treatment for PSS and provide insights to facilitate well-designed studies in the future.