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Analysis of GPS signal environment at DGNSS stations (DGNSS 기준국 관측환경 분석)

  • Sohn, Dong-Hyo;Park, Kwan-Dong;Won, Ji-Hye;Choi, Yong-Kwon;Kee, Chang-Don
    • Journal of Navigation and Port Research
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    • v.35 no.8
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    • pp.625-629
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    • 2011
  • In this study, we analyzed the signal environment of 17 DGNSS stations operated by DGPS Central Office through TEQC quality checking, visibility analysis and site visits. With TEQC, we produced times series of four indices of TEQC quality checking: observation ratio, L1 pseudorange multipath, L2 pseudorange multipath, and the frequency of cycle slip events. From visibility analysis, the directions where missing observations are happening were identified and the result was verified through onsite investigation. Without considering TEQC indices at the six sites(Palmido, Eochungdo, Geomundo, Pyeongchang, Seongju, and Chungju), the average TEQC indices were: 98% observation ratio, 0.19m of L1 pseudorange multipath, 0.71m of L2 pseudorange multipath, and 1.3 cycle slips per 1000 observations. The observation ratios at Palmido and Eochungdo were low. It was found that receiver settings were incorrect so that they could track the P2 signal of GPS satellites with L2C capability. No signal-blocking obstacles were found around the Geomundo station except the lighthouse. Thus, we guess that the poor TEQC indices at the site are believed to be caused by problems in the GPS hardware or cables. The low observation ratio at Pyeongchang is being caused by the surrounding hills blocking the satellite view from the south to the northwest directions. Even though all of four TEQC indices were bad at Seongju and Chungju stations, we found that the signal reception environment at the two sites is in good condition. We think that the quality indices got poor probably because of malfunctioning equipment. So, further investigation is needed for the Seongju and Chungju sites.

The Study on The variational Forms of Sa-Ahm's 5 Element Acupuncture Method (사암침법(舍巖鍼法)의 변형(變形)에 관(關)한 연구(硏究))

  • Kim, Dar-Hoo;Kim, Jung-Han
    • Korean Journal of Oriental Medicine
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    • v.2 no.1
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    • pp.337-380
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    • 1996
  • 'Nei Jing(內徑)' first defined the interrelationship of the true and tile false between evil factor affecting health(雅氣) and vital essence energy(精氣). According to 「'Nei Jing(內徑)', the above interrelationship is explained as 'If state of evil domination is considered as sthenia-syndrome(雅氣盛則實), if the consumption of healthy energy Is considered as asenia-syndrome(精氣尊則虛): 'Nei Jing(內徑)', proposed major features of the medicall treatment by 'regluate the vatal energy of asthenia and sthenia, treat the sthenia-syndrome by purgation, and treat the asenia-syndrome by therapy of invigoration(調其氣之虛實, 實則瀉之, 虛則補之): The above interrelationship was interpreted as 'treat the asthenia-syndrome of child organ by invigorating the mother organ(虛者補其母)'in the 69th of 'The Classic on Difficulty',(難經 六十九難). Go-Mu(高武) of Myung-dynasty describe therapy for invigoration and purgation of itself-meridian(自經 補瀉法), which locating acupuncture points according to the Therorr of Five Element in the five shu points of itself-meridian(自經 五유穴), based on the generation in the ${\ulcorner}$A Synthetical Book of Acupuncture and Moxibustion(針灸聚英)${\lrcorner}$, Sae-hyun Jang(張世賢) further extended location acupuncture points of the five shu points to the other-meridian in the ${\ulcorner}$Gyeo Jung Do Ju Nan Gyung(校正圖註難經)${\lrcorner}$ Sa-Ahm's 5 Element Acupuncture Method(舍嚴五行鍼法) was originated in 1644, the middle of the Yi-dynasty. It linked the reinforcing and reducing in acupuncture therapy which incorporated tlle asthenia-syndrome and sthenia-syndrome of the hollow organs, based on principle of the Yin Yang 5 Element Theory(陰陽五行學說), not only to the generation in the 5 element(相生關係) but also to the restriction in the 5 element(相剋關係). Furthermore it was devised for the medical treatment by comning therapy for invigoration and purgation of itself-meridian(自經 補瀉法) with that of the other-meridian. Even though many original forms(正形) of the therapy for invigoration and purgation of the Yin Yang 5 Element Theory comply with the principle of the generation and the restriction based on the principle of the Yin Yang 5 Element Theory are abailable, variational forms(變形) are also recognized by examining the nature of the Sa-Ahm's 5 Element Acupuncture Method(舍嚴五行鍼法), For this reason, it is very difficult to understand the Sa-Ahm's 5 Element Acupuncture Method(舍嚴五行鍼法) thoroughly. therefore, those variational forms are obstacles for the beginners to study the Sa-Ahm's 5 Element Acupuncture Method. In order to understand the principle of the practical clinical application of the Sa-Ahm's 5 Element Acupuncture Method, this study investigated which principle was based on the variations of the locating acupuncture points' method for the acupuncture prescription.

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Simulations of Temporal and Spatial Distributions of Rainfall-Induced Turbidity Flow in a Reservoir Using CE-QUAL-W2 (CE-QUAL-W2 모형을 이용한 저수지 탁수의 시공간분포 모의)

  • Chung, Se-Woong;Oh, Jung-Kuk;Ko, Ick-Hwan
    • Journal of Korea Water Resources Association
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    • v.38 no.8 s.157
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    • pp.655-664
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    • 2005
  • A real-time monitoring and modeling system (RTMMS) for rainfall-induced turbidity flow, which is one of the major obstacles for sustainable use of reservoir water resources, is under development. As a prediction model for the RTMMS, a laterally integrated two-dimensional hydrodynamic and water quality model, CE-QUAL-W2 was tested by simulating the temperature stratification, density flow regimes, and temporal and spatial distributions of turbidity in a reservoir. The inflow water temperature and turbidity measured every hour during the flood season of 2004 were used as the boundary conditions. The monitoring data showed that inflow water temperature drop by 5 to $10^{\circ}C$ during rainfall events in summer, and consequently resulted in the development of density flow regimes such as plunge flow and interflow in the reservoir. The model showed relatively satisfactory performance in replicating the water temperature profiles and turbidity distributions, although considerable discrepancies were partially detected between observed and simulated results. The model was either very efficient in computation as the CPU run time to simulate the whole flood season took only 4 minutes with a Pentium 4(CPU 2.0GHz) desktop computer, which is essentially requited for real-time modeling of turbidity plume.

A Study on the Exposure Dose of Frequent Workers and Radiation Workers in a University Hospital (일개 대학병원의 수시출입자와 방사선작업종사자의 피폭선량에 관한 고찰)

  • Joo-Ah Lee
    • Journal of the Korean Society of Radiology
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    • v.17 no.4
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    • pp.581-587
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    • 2023
  • In this study, we tried to provide basic data for radiation safety management by comparing and analyzing the exposure doses of radiation workers and frequent workers at C University Hospital in Incheon. From January 2021 to December 2022, surface dose and deep dose were analyzed for 30 radiation workers and 8 frequent workers who worked at C university hospital in Incheon. Radiation workers were targeted at radiation technicians and nurses working in the radiation oncology department and nuclear medicine department, and frequent visitors were targeted at frequent workers who manage and clean facilities in the same radiation management area. In the radiation worker group, 3.1 per 10,000 radiation technologist, 1.2 per 100,000 nurses, and 4.5 per 1,000,000 frequent workers showed the possibility of developing side effects on the lungs. The probability of radiation oncology was 1.1 per 10,000 for radiation technologist and 5.2 per 1,000,000 for nurses, and the probability of radiation technologist in nuclear medicine was 2.9 per 10,000 and for nurses was 7.1 per 1,000,000. It is hoped that this study can be used as basic data in future revisions on frequent workers, and it is considered that it will be used as basic data in the field of obstacles in relation to the stochastic effect of radiation in the future.

Pseudo-DC Resistivity Survey for Site Investigation at Urban Areas with Ambient Electrical Noises (전기잡음 간섭이 있는 도심지 지역 탐사를 위한 유사직류 전기비저항 기법)

  • Joh, Sung-Ho;Kim, Bong-Chan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.1C
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    • pp.37-44
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    • 2010
  • Recently, urban retrofit and extension, development of new buildings and facilities, and construction of underground structures like subway tunnels in urban areas give rise to significance of site investigation at urban areas. However, ambient electric noises, traffic vibrations, embedded objects work as obstacles to high-quality and accuracy in site investigation at urban areas. In this paper, a new technique called the pseudo-DC resistivity survey (in brief, PDC-R) was proposed to minimize the adverse effect of ambient electrical noises in resistivity survey. PDC-R technique utilizes an AC current with frequency range of 0.1 to 1.0 Hz rather than DC current, which is used for conventional resistivity survey. The motivation of using low-frequency AC current is to avoid 60-Hz components or its multiples in the resistivity survey which ambient noises are mostly composed of. The implementation of PDC-R technique also included the parametric study on skin effect, frequency effect and current-level effect, which led to the determination of optimal values of frequency and current level for PDC-R survey. The reliability and feasibility of PDC-R technique was verified through field tests, accompanied by the comparison with DC resistivity survey and CapSASW tests.

Midwives' Perceptions of the Importance of Teaching the Lamaze Method of Childbirth Preparation, Their Practice of it and Inhibiting Factors. (조산사의 라마즈 산전교육에 대한 중요성 인식과 수행정도 및 저해요인에 관한 연구)

  • Yoon, Gui-Nam;Cho, Mi-Young
    • 모자간호학회지
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    • v.2 no.1
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    • pp.21-33
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    • 1992
  • This study was done to investigate how importantly midwives thought of Lamaze Method of Childbirth, how satisfactorily they performed their Lamaze Method of Childbirth and what inhibited their activities from being performed if not done satisfactorily. The subjects of this study were 76midwives at midwifery in Pusan, Deagu, Kyungnam and Kyungbok. Data were collected by using questionaire from Sep. 1 to Sep.30, 1991. The measurement tools was maded by the researcher based on Kim's scale for prenatal nursing activities. The statistical analysis was done with based statistical values likes frequencies, means, standard deviations and advanced methods such as Pearson's correlation coefficient, 1-test, F-test, F-test by using SPSS package program. The results of this study can be summarized as follows ; 1. The results of Investigating perception according to importance degree and performance degree of Lamaze Method of Childbring showed that midwives were slightly below both perception according to importance(2.17) and performance(2.16) of Lamaze Method of Childbirth 2. Inhibiting factors of Lamaze Method of Childbirth were abscence of husband(3.08), lack of teaching room(2.71), and lack of books or literature of Lamaze Method (2.58). 3. There appears to be a positive relation between perception according to importance degree and performance degree of Lamaze Method of Childbirth (r=0.69, P<0.01). There appears to be a negative relation between perception according to importance degree and inhibit factors of performance (r=-0.38, P<0.01). There appears to be a negative relation between performance and inhibit factors of performance (r=-0.22. P<0.01). 4. The item of highest perception defree in prenatal education is 1st, Consultation about sexual life (2.53), End, illustration of the importance of a bath and perinal cleanliness and Avoidance of excessive respiration method and also its comfortable application during uterine contractility(2.45). The item of lowest perception degree is about pregnant symptom sign and predicted date of birth (E.D.C.). On the other hand, The item of highest performance degree is education about nurtrition during pregnacy. 2nd, Illustration of the Importance of a bath and perineal cleanness(2.45). The lowest one is leaching the pregnant woman and her family about the role of husband and her family and also teaching the couple to learn exercise and respiration method (1.84). Though importance perception degree and performance degree is low. Midwives who wert subject in this research shoves that they perform general items concerning prenatal education well. 5. In the relationship between perception according to importance degree of Lamaze Method of Childbirth and the general characteristics of subjects, the differences in mean number of visiting pregnacies for 1 month. 6. In the relationship between performance degree of Lamaze Method of Childbirth and the general characteristics of subjects, the differences in age, marriage, and mean number of visiting pregnancies for 1 month. With the above information we see the importance of midwife prenatal care education and high correlation between performance degree and perception degree. When Lamaze prenatal education is well performed the number of pregnant woman who have follow-up, check-ups increase. Therefore in this research we can validity that there is a relation between Lamaze prenatal education and patient follow-up. This research showes in a situation where if one does not maximally perform a prenatal education there is a possibility that the popular use of midwife activities may encounter obstacles so the education to save new knowledge and training for prenatal education is needed as a function of Lamaze prenatal education, when a special Lamaze education is well performed for the pregnant woman, who follows-up at amidwife clinic. With the above conclusion we can suggest : 1. Continued research which minimized obstacles to Lamaze prenatal education is needed. 2. The official method of midwives is necessary.

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Past and Future Regional Climate Change in Korea

  • Kwon, Won-Tae;Park, Youngeun;Min, Seung-Ki;Oh, Jai-Ho
    • The Korean Journal of Quaternary Research
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    • v.17 no.2
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    • pp.161-161
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    • 2003
  • During the last century, most scientific questions related to climate change were focused on the evidence of anthropogenic global warming (IPCC, 2001). There are robust evidences of warming and also human-induced climate change. We now understand the global, mean change a little bit better; however, the uncertainties for regional climate change still remains large. The purpose of this study is to understand the past climate change over Korea based on the observational data and to project future regional climate change over East Asia using ECHAM4/HOPE model and MM5 for downscaling. There are significant evidences on regional climate change in Korea, from several variables. The mean annual temperature over Korea has increased about 1.5∼$1.7^{\circ}C$ during the 20th century, including urbanization effect in large cities which can account for 20-30% of warming in the second half of the 20th century. Cold extreme temperature events occurred less frequently especially in the late 20th century, while hot extreme temperature events were more common than earlier in the century. The seasonal and annual precipitation was analyzed to examine long-term trend on precipitation intensity and extreme events. The number of rainy days shows a significant negative trend, which is more evident in summer and fall. Annual precipitation amount tends to increase slightly during the same period. This suggests an increase of precipitation intensity in this area. These changes may influence on growing seasons, floods and droughts, diseases and insects, marketing of seasonal products, energy consumption, and socio-economic sectors. The Korean Peninsular is located at the eastern coast of the largest continent on the earth withmeso-scale mountainous complex topography and itspopulation density is very high. And most people want to hear what will happen in their back yards. It is necessary to produce climate change scenario to fit forhigh-resolution (in meteorological sense, but low-resolution in socio-economic sense) impact assessment. We produced one hundred-year, high-resolution (∼27 km), regional climate change scenario with MM5 and recognized some obstacles to be used in application. The boundary conditions were provided from the 240-year simulation using the ECHAM4/HOPE-G model with SRES A2 scenario. Both observation and simulation data will compose past and future regional climate change scenario over Korea.

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Planarization of SUS310 Metal Substrate Used for Coated Conductor Substrate by Chemical Solution Coating Method (화학적인 용액 코팅방법에 의한 박막형 고온초전도체에 사용되는 SUS310 금속모재의 평탄화 연구)

  • Lee, J.B.;Lee, H.J.;Kim, B.J.;Kwon, B.K.;Kim, S.J.;Lee, J.S.;Lee, C.Y.;Moon, S.H.;Lee, H.G.;Hong, G.W.
    • Progress in Superconductivity
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    • v.12 no.2
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    • pp.118-123
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    • 2011
  • The properties of $2^{nd}$ generation high temperature superconducting wire, coated conductor strongly depend on the quality of superconducting oxide layer and property of metal substrate is one of the most important factors affecting the quality of coated conductor. Good mechanical and chemical stability at high temperature are required to maintain the initial integrity during the various process steps required to deposit several layers consisting coated conductor. And substrate need to be nonmagnetic to reduce magnetization loss for ac application. Hastelloy and stainless steel are the most suitable alloys for metal substrate. One of the obstacles in using stainless steel as substrate for coated conductor is its difficulties in making smooth surface inevitable for depositing good IBAD layer. Conventional method involves several steps such as electro polishing, deposition of $Al_2O_3$ and $Y_2O_3$ before IBAD process. Chemical solution deposition method can simplify those steps into one step process having uniformity in large area. In this research, we tried to improve the surface roughness of stainless steel(SUS310). The precursor coating solution was synthesized by using yttrium complex. The viscosity of coating solution and heat treatment condition were optimized for smooth surface. A smooth amorphous $Y_2O_3$ thin film suitable for IBAD process was coated on SUS310 tape. The surface roughness was improved from 40nm to 1.8 nm by 4 coatings. The IBAD-MgO layer deposited on prepared substrate showed good in plane alignment(${\Delta}{\phi}$) of $6.2^{\circ}$.

Complex oncologic resection and reconstruction of the scalp: Predictors of morbidity and mortality

  • Tecce, Michael G.;Othman, Sammy;Mauch, Jaclyn T.;Nathan, Shelby;Tilahun, Estifanos;Broach, Robyn B.;Azoury, Said C.;Kovach, Stephen J.
    • Archives of Craniofacial Surgery
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    • v.21 no.4
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    • pp.229-236
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    • 2020
  • Background: Oncologic resection of the scalp confers several obstacles to the reconstructive surgeon dependent upon patient-specific and wound-specific factors. We aim to describe our experiences with various reconstructive methods, and delineate risk factors for coverage failure and complications in the setting of scalp reconstruction. Methods: A retrospective chart review was conducted, examining patients who underwent resection of fungating scalp tumors with subsequent soft-tissue reconstruction from 2003 to 2019. Patient demographics, wound and oncologic characteristics, treatment modalities, and outcomes were recorded and analyzed. Results: A total of 189 patients were appropriate for inclusion, undergoing a range of reconstructive methods from skin grafting to free flaps. Thirty-three patients (17.5%) underwent preoperative radiation. In all, 48 patients (25.4%) suffered wound site complications, 25 (13.2%) underwent reoperation, and 47 (24.9%) suffered from mortality. Preoperative radiation therapy was an independent risk factor for wound complications (odds ratio [OR], 2.85; 95% confidence interval [CI], 1.1-7.3; p=0.028) and reoperations (OR, 4.45; 95% CI, 1.5-13.2; p=0.007). Similarly, the presence of an underlying titanium mesh was an independent predictor of wound complications (OR, 2.49; 95% CI, 1.1-5.6; p=0.029) and reoperations (OR, 3.40; 95% CI, 1.2-9.7; p=0.020). Both immunosuppressed status (OR, 2.88; 95% CI, 1.2-7.1; p=0.021) and preoperative radiation therapy (OR, 3.34; 95% CI, 1.2-9.7; p=0.022) were risk factors for mortality. Conclusion: Both preoperative radiation and the presence of underlying titanium mesh are independent risk factors for wound site complications and increased reoperation rates following oncologic resection and reconstruction of the scalp. Additionally, preoperative radiation, along with an immunosuppressed state, may predict patient mortality following scalp resection and reconstruction.

A Study on the Mobile Communication System for the Ultra High Speed Communication Network (초고속 정보통신망을 위한 이동수신 시스템에 관한 연구)

  • Kim, Kab-Ki;Moon, Myung-Ho;Shin, Dong-Hun;Lee, Jong-Arc
    • Journal of IKEEE
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    • v.2 no.1 s.2
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    • pp.1-14
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    • 1998
  • In this paper, Antenna, LNA, Mixer, VCO, and Modulation/Demodulation in Baseband processor which are the RF main components in Wireless LAN system for ultra high-speed communications network are studied. Antenna bandwidth and selective fading due to multipath can be major obstacles in high speed digital communications. To solve this problem, wide band MSA which has loop-structure magnetic antenna characteristics is designed. Distributed mixer using dual-gate GaAs MESFET can achieve over 10dB LO/RF isolation without hybrid, and minimize circuit size. As linear mixing signal is produced, distortions can be decreased at baseband signals. Conversion gain is achieved by mixing and amplification simultaneously. Mixer is designed to have wide band characteristics using distributed amplifier. In VCO design, Oscillator design method by large signal analysis is used to produce stable signal. Modulation/Demodulation system in baseband processor, DS/SS technique which is robust against noise and interference is used to eliminate the effect of multipath propagation. DQPSK modulation technique with M-sequences for wideband PN spreading signals is adopted because of BER characteristic and high speed digital signal transmission.

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