• 한국정밀공학회지
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• 제31권5호
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• pp.403-409
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• 2014

For ground-based telescope application, the performance assessment of tip-tilt actuator is important because the optical quality of telescope depends upon the windshake compensation ability of the fast steering secondary mirror. But it is difficult to measure the performance characteristics of the actuators due to the large size mirror and test facilities including the vacuum support and structural frame. In this paper, the full-scale tip-tilt test bed for the large size secondary mirror with diameter of 1m is built and the several tests are performed including the range, resolution and frequency response function. From the measurement results, it is shown that the tip-tilt actuator can successfully compensate the windshake with frequency of maximum 12 Hz and be a candidate for the Giant Magellan Telescope.

• 기본간호학회지
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• 제12권3호
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• pp.317-324
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• 2005

Purpose: The study was done to investigate whether positioning relieves the back pain and enhances comfort during bed rest after transhepatic arterial chemoembolization(TACE). Methods: A quasi-experimental design with non-equivalent control group non-synchronized design was used. The experimental group was placed semi Fowler's position for the first 2 hours. The following 4 hours the position was rotated hourly between 30 degrees laterally inclined position and a semi Fowler's position. The control group was maintained in a supine position for the 6 hours. Data were analyzed using t-test, $x^2$-test, Fisher's exact test and repeated measures ANOVA. Results: 1) Back pain intensity significantly decreased in the experimental group compared to the control group. 2) Comfort level significantly decreased in both groups, but there was no significant difference between the two groups. 3) There were no hematoma and bleeding complication in either group. In addition, there was no significant difference in urinary retention between the two groups. 4) Analgesics were less frequently taken by the experimental group. Conclusion: These results suggest that positioning relieves back pain without causing an increased incidence of hematoma and bleeding formation after TACE and this nursing intervention might help patients be more comfortable during the treatment of TACE.

• International Journal of Railway
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• 제1권2호
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• pp.64-71
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• 2008

The quality of track-bed fills of railways has been controlled by field measurements of density $({\gamma}_d)$ and the results of plate-load tests. The control measures are compatible with the design procedures whose design parameter is $k_{30}$ for both ordinary-speed railways and high-speed railways. However, one of fatal flaws of the design procedures that there are no simple laboratory measurement procedures for the design parameters ($k_{30}$ or, $E_{v2}$ and $E_{v2}/E_{v1}$) in design stage. A new quality control procedure, in parallel with the advent of the new design procedure, is being proposed. This procedure is based upon P-wave velocity involving consistently the evaluation of design parameters in design stage and the field measurements during construction. The Key concept of the procedure is that the target value for field compaction control is the P-wave velocity determined at OMC using modified compaction test, and direct-arrival method is used for the field measurements during construction. The procedure was verified at a test site and the p-wave velocity turned out to be an excellent control measure. The specifications for the control also include field compaction water content of OMC${\pm}$2% as well as the p-wave velocity.

• 한국기계가공학회지
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• 제20권2호
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• pp.38-44
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• 2021

To cater to the transition from single-color to multicolor/multi-material printing, this paper proposes a cartridge-replacing type multi-nozzle Fused Depositon Modeling(FDM) three-dimensional (3D) printer. In the test printing run, tool change failure/wobble/layer shift occurred. It was confirmed that improper support was the cause of this tool change failure. As a solution, spline and electromagnetic cartridges were designed. Wobble was caused by machine vibration and the motor stepping out. To minimize wobble, an additional Z-axis was installed, and the four-point bed leveling method was used instead of the three-point bed leveling method. The occurrence of layer shift was ascribed to the eccentricity of the Z-axis lead screw. Therefore, slit coupler was replaced with an Oldham type. In addition to the mechanical supplementation, the control environment was integrated to prevent accidents and signal errors due to wire connections. Before the final test printing run, a rectifier circuit was added to the motor to secure precise control stability. The final test printing run confirmed that the wobble/layer shift phenomenon was minimized, and the maximum error between layers was reduced to 0.05.

• 한국산업정보학회논문지
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• 제14권1호
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• pp.56-63
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• 2009

Mobile IP 단말기들에 탑재되는 운영체제는 일반적인 PC에서 탑재되는 운영체제와는 달리 확실한 독점체제가 확립되지 않은 상태이다. 따라서 당분간 Mobile IP 단말기에 운영되는 운영체제는 다양한 종류의 운영체제가 사용될 것으로 추정된다. 이러한 환경은 운영체제에 상관없이 변종되는 바이러스들에 매우 취약한 환경이며, 개별 단말기에서 사용되는 운영체제가 다양하기 때문에 이들 바이러스를 효율적으로 검출하여 치료하는 기술 개발을 매우 난해하게 한다. 본 논문에서는 VMware를 이용하여 다양한 운영체제에서 변종 바이러스를 테스팅할 수 있는 시스템을 설계하고 구현하였다. 또한 이를 실제 Mobile 환경에서 운영하기 위한 Prototype 시스템을 구축하였다.

• 정보보호학회논문지
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• 제33권2호
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• pp.325-336
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• 2023

자율주행 기술이 발전함에 따라 차량에 탑재되는 외부접점 센서의 수가 증가하고 있으며 특히 차량용 초음파 센서는 버스 토폴로지 형태로서 LIN 프로토콜을 사용하여 연결되며 주변을 감지하고 상태 메시지를 전송하여 차량 내부 네트워크에 접근한다. LIN은 프로토콜의 보안성이 검증되지 않아 공격에 취약하기 때문에 안전성을 평가하기 위한 테스트가 필요하지만, 물리적인 제약으로 인해 실제 차량을 이용한 분석에 한계가 있으며 이를 위한 테스트 환경이 부족하기 때문에 테스트에 어려움이 있다. 따라서, 본 논문에서는 LIN 프로토콜 분석 및 테스트를 위해 CAN과의 연동 분석이 가능한 테스트베드를 개발하고 초음파 센서를 이용하여 그 효용성을 검증하였다.

• 한국농공학회논문집
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• 제56권6호
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• pp.149-158
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• 2014

The effects of spot cooling on growing ever-bearing strawberry in hydroponic cultivation during summer by spot cooling system was estimated in plastic greenhouse located in Pyeongchang. The temperature of cooling water was controlled by heat pump and maintained at the range of $15{\sim}20^{\circ}C$. Cooling pipes were installed in root zone and very close to crown. Spot cooling effect was estimated by applying system in three cases which were cooling root zone, crown plus root zone, and crown only. White low density polyethylene pipe in nominal diameter of 16 mm was installed on crown spot, and Stainless steel flexible pipe in nominal diameter of 15A was installed in root zone. Crown and root zone cooling water circulation was continuously performed at flowrates of 300 ~ 600 L/hr all day long. Strawberry yields by test beds were surveyed from Aug. 1 to Sep. 30. The accumulated yield growth rate compared with a control bed of crown cooling bed was 25 % and that of crown plus root zone cooling bed was 25 % and that of root zone cooling bed was 20 %. The temperatures of root spot in root zone cooling was maintained at $18{\sim}23.0^{\circ}C$ and that of crown spot in crown cooling was maintained at $19{\sim}24^{\circ}C$. Also, the temperatures of root spot in crown plus root zone cooling bed was maintained at $17.0{\sim}22.0^{\circ}C$ and that of crown spot was maintained at $19{\sim}25^{\circ}C$.

• 임상간호연구
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• 제28권1호
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• pp.1-12
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• 2022

Purpose: The purpose of this study is to investigate the association between the nurse staffing level and the patient mortality using Korean National Health Insurance data. Methods: The data of 1,068,059 patients from 913 hospitals between 2015 and 2016 were analyzed. The nurse staffing level was categorized based on the bed-to-nurse ratio in general wards, intensive care units (ICUs), and hospitals overall. The x² test and generalized estimating equations (GEE) multilevel multivariate logistic regression analyses were used to explore in-hospital mortality and 30-day mortality after admission. Results: The in-hospital mortality rate was 2.9% and 30-day mortality after admission rate was 3.0%. Odd Ratios (ORs) for in-hospital mortality were statistically lower in general wards with a bed-to-nurse ratio of less than 3.5 compared to that with 6.0 or more (OR=0.72, 95% CI=0.63~0.84) and in ICUs with a bed-to-nurse ratio of less than 0.88 compared to that with 1.25 or more (OR=0.78, 95% CI=0.66~0.92). ORs for 30-day mortality after admission were statistically lower in general wards with a bed-to-nurse ratio of less than 3.5 compared to that with 6.0 or more (OR=0.83, 95% CI=0.73~0.94) and in ICUs with a bed-to-nurse ratio of less than 0.63 compared to that with 1.25 or more (OR=0.85, 95% CI=0.72~1.00). Conclusion: To reduce the patient mortality, it is necessary to ensure a sufficient number of nurses by improving the nursing fee system according to the nurse staffing level.

• 상하수도학회지
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• 제35권6호
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• pp.533-544
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• 2021

전자 및 화학 산업의 초순수 생산 및 원자력 발전소의 부식 제어를 위해 이온교환 수지탑의 성능 파악이 필수적이다. 따라서 본 연구에서는 4종의 H 및 ETAH 형 양이온 교환수지가 채워진 양이온 및 혼상 이온교환수지탑에 미량의 NaCl를 포함하는 에탄올아민(ETA) 및 암모니아(NH₃) 용액을 주입하여 양이온 파과특성을 조사하였다. 조사 결과, 주성분인 ETAH⁺ 및 NH₄⁺와 달리, 미량성분인 Na⁺는 (이론적교환용량의 3배 이상) 시험기간 동안 수지탑 출구에서 파과 및 오버슈팅 현상이 나타나지 않았다. H형 수지탑의 파과현상은 ETAH⁺ 및 NH₄⁺가 순서대로 일어났고, 오버슈팅은 NH₄⁺가 파과할때 ETAH⁺에 대해서 발생했다. 파과영역의 너비로 결정되는 상대적 선택도는 NH₄⁺가 ETAH⁺보다 최대 51.5 % 더 높았다. 유입수 Na⁺ 농도가 높을수록, 선택도는 감소하고 오버슈팅 현상은 증가하였다. 이온교환 수지의 고유 특성을 개선하여 감소시킬 수 있는 Na⁺ 누출은, ETAH형에서 높았고 4종의 양이온수지에 대해 동일하지 않은 것으로 조사되었다.

• 대한기계학회논문집
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• 제19권7호
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• pp.1780-1786
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• 1995

The main goal of the present study is to establish the techniques and methodolgies of turbine performance test through evaluating the objective turbine test piece, and checking the reliability of the self-developed test facility by performing a series of turbine tests under ambient temperature condition. A high speed coupling, a lubrication system and a test bed of the test facility were modified through a series of preliminary test in order to reduce the vibration and oil leakage. The flowrate control of the test facility and data acquisition were accomplished by using a software called "Labview" The measurement of shaft horse power and control of rotational speed according to the conditions of turbine rotation were performed by a separate system. The preliminary evaluation of the measured data suggests that the developed test facility and the test technique can be used reliably for the performance test of turbines with the minor improvement.provement.