• 한국산림과학회지
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• 제89권3호
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• pp.306-309
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• 2000

우리나라 해안지역에 널리 분포하고 있는 해송에 극심한 피해를 주고 있는 솔껍질깍지벌레는 1963년 전남 고흥에서 최초로 발생된 것으로 추정되며, 그 후 계속 확산되어 현재 서해안과 남해안 지역으로 분포가 확대되었다. 본 연구는 1983년부터 1999년까지 임업연구원에서 수행한 발생선단지 조사 자료를 토대로 확산방향을 최초 발생지로부터 서해안쪽으로의 북향, 내륙지역으로의 동북향, 남해안쪽으로의 동향 등 3방향으로 구분하여 확산 유형을 분석하였다. 내륙으로의 확산은 해송의 밀도가 높은 곳에서는 연평균 약 4.3km의 확산속도를 보였지만 1990년대 초반부터 해송의 밀도가 낮아지는 곳에서는 속도가 매우 느려졌다. 해송의 밀도가 높은 서해안쪽 북향과 남해안쪽 동향은 확산속도가 각각 연평균 5.9, 3.3km로서 북향으로의 확산속도가 가장 높았다.

• 대한간호학회지
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• 제25권3호
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• pp.549-561
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• 1995

This study was designed to identify the relation-ship of perceived social support on self-esteem and hopelessness in patients with chronic renal failure who are hemodialysis. The subjects of this study were the 50 patients who were registered in the hemodialysis department of the two hospitals. The data were collected using a questionnaire and The period of the data collection was from August 9 to 16, 1993. The instruments for this study were the perceived social support scale designed by Park Ji-Won, the self -esteem scale designed by Rosenberg and the hopelessness scale designed by Beck et al. The data were analyzed using frequencies, percentages, t-test, ANOVA, and .Pearson correlation coefficient. The results are summarized as follows ; 1. The degree of support according to the type of perceived social support ranged down in the fol-lowing order from high to low the mean emotion-al support 21.12, the mean informational support 19.58, the mean appraisal support 17.00, the mean material support 15.22, the man self-esteem was 32.00 and the mean hopelessness was 60.48. 2. Test for hypothesis ; Hypothesis 1, "The higher the level of perceived social support in patients on hemodialysis, the higher their level of self-esteem will be. " was not supported(r=.05, p=0.74). Hypothesis 2, "The higher the level of perceived social support in patients on hemodialysis, the lower their level of hopelessness will be. " was supported(r=-0.53, p=0.00). 3. The relations between general characteristics and the level of perceived social support, self-esteem, and hopelessness ; (1) The 'Gender'(P=0.04), 'Occupation'(P=0.04), 'Education'(P=0.00), 'Married state'(P=0.00) 'Duration of Hemodialysis'(P=0.00) and 'In-come'(P=0.00) of the subjects were related to perceived social support and showed a statistically significant difference. (2) No general characteristics of the subjects were related self-esteem in a statistically significant way. (3) The 'Education'(P=0.00) , 'Income'(P=0.00) of the subjects were related to hopelessness and showed a statistically significant difference. Thus, it is concluded that social support must be included in nursing interventions for patients with chronic renal failure on hemodialysis.

• 상하수도학회지
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• 제24권1호
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• pp.93-101
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• 2010

Reverse osmosis (RO) membranes have been widely used for desalination as well as water and wastewater treatment facilities. Cleaning process is important to maintain stable operation as well as prevention of membrane fouling. Purpose of this research is to analyze electrostatistic and chemical characteristics after cleaning of RO membrane against $SiO_2$ scale. Four RO membranes of polyamide are used and examined about effect of chemical cleaning. EDTA (ethylene diamine tetraacetic acid) and SDS (sodium dodecil sulfate) and NaOH are applied for cleaning process after operation in synthetic water. Then, cleaning was performed with chemicals such concentration as 6hr, 12hr and 24hr, respectively. As a result, transmittances of FT-IR of four membranes are compared at each cleaning concentration. Ta/Tv shows difference of chemical composition between new membrane and cleaning membrane after cleaning. Type B of RO membrane is turned out to be most vulnerable to cleaning among four membranes. In terms of zeta potential, new membrane has -16 mV to +6 mV on pH while scaled membrane has -18 mV to 2 mV. However, it changed -23mV to 0.9 mV after cleaning. In comparison with existing salt rejection of RO membranes after cleaning, the rejection of the membranes goes down 0.7% maximum. Though cleaning changes the characteristics of membrane surface, it does not greatly affect salt rejection. pH is a critical factor to flux change in PA (polyamide) membrane.

• Wind and Structures
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• 제34권2호
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• pp.199-213
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• 2022

The current study investigates the dynamic effects in the tornado-structure response of an aeroelastic self-supported lattice transmission tower model tested under laboratory simulated tornado-like vortices. The aeroelastic model is designed for a geometric scale of 1:65 and tested under scaled down tornadoes in the Wind Engineering, Energy and Environment (WindEEE) Research Institute. The simulated tornadoes have a similar length scale of 1:65 compared to the full-scale. An extensive experimental parametric study is conducted by offsetting the stationary tornado center with respect to the aeroelastic model. Such aeroelastic testing of a transmission tower under laboratory tornadoes is not reported in the literature. A multiaxial load cell is mounted underneath the base plate to measure the base shear forces and overturning moments applied to the model in three perpendicular directions. A three-axis accelerometer is mounted at the level of the second cross-arm to measure response accelerations to evaluate the natural frequencies through a free-vibration test. Radial, tangential, and axial velocity components of the tornado wind field are measured using cobra probes. Sensitivity analyses are conducted to assess the variation of the structural dynamic response associated with the location of the tornado relative to the lattice transmission tower. Three different layouts representing the change in the orientation of the tower model relative to the components of the tornado-induced loads are considered. The structural responses of the aeroelastic model in terms of base shear forces, overturning moments, and lateral accelerations are measured. The results are utilized to understand the dynamic response of self-supported transmission towers to the tornado-induced loads.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권12호
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• pp.4420-4438
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• 2021

Image dehazing is an ill-posed problem which is far from being solved. Traditional image dehazing methods often yield mediocre effects and possess substandard processing speed, while modern deep learning methods perform best only in certain datasets. The haze removal effect when processed by said methods is unsatisfactory, meaning the generalization performance fails to meet the requirements. Concurrently, due to the limited processing speed, most dehazing algorithms cannot be employed in the industry. To alleviate said problems, a lightweight fast dehazing network based on a multiple scale-patch framework (MSP) is proposed in the present paper. Firstly, the multi-scale structure is employed as the backbone network and the multi-patch structure as the supplementary network. Dehazing through a single network causes problems, such as loss of object details and color in some image areas, the multi-patch structure was employed for MSP as an information supplement. In the algorithm image processing module, the image is segmented up and down for processed separately. Secondly, MSP generates a clear dehazing effect and significant robustness when targeting real-world homogeneous and nonhomogeneous hazy maps and different datasets. Compared with existing dehazing methods, MSP demonstrated a fast inference speed and the feasibility of real-time processing. The overall size and model parameters of the entire dehazing model are 20.75M and 6.8M, and the processing time for the single image is 0.026s. Experiments on NTIRE 2018 and NTIRE 2020 demonstrate that MSP can achieve superior performance among the state-of-the-art methods, such as PSNR, SSIM, LPIPS, and individual subjective evaluation.

• 보건행정학회지
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• 제4권1호
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• pp.107-122
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• 1994

Many alternatives have been discussed to reduce the medical expenditure and to use the medical resources effectively. Many studies about the economies of scale have been done for the last several decades. This study has analyzed the relationship between the number of beds and the mean expense per hospitalization day in Korea. A Cost Function Model was identified and we wanted to see the minimum optimal size with the cheapest mean expense per hospitalization day. The result is as follows; 1. In the Cost Function Mode, (the number of beds)$^{2}$, the number of personnel, productivity and training institutions are the factors that statisticaly influence the mean expenses. 2. By the univariate analysis the mean expense proved to be the smallest as the level of 150-200bed, The breaked down of the components of expenses shows that the mean labor cost is much different from the mean value of material and administration costs, and that hospital with 150-200 beds also have the minimal expense. The mean expense goes up dramatically in hospitals of 450 beds or more. 3. When the other conditions are constant, according to the multiple regression analysis of the mean expense per adjusted hospitalization day the minimum optimal size with the cheapest expense is a hospital with 191 beds and the hospital with 230 beds takes the lowest mean labor cost. The material or administration costs are not influenced by hospital size. This research has limitation in measuring the variables that influence hospital xpenses, in estimating hospital output by the number of beds in considering outpatient cost and in securing representativeness of hospitals because many hospitals made no responses to the research questionnare. But it is valuable and helpful for development of health policy to figure out the number of beds with the cheapest expense per hospitalization day.

• 한국압력기기공학회 논문집
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• 제19권2호
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• pp.155-162
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• 2023

In nuclear power plants, the flow rate information is a major indicator of the performance of rotating equipment such as pumps, and is a very important one required for facility operation and maintenance. To measure a flow rate, various types of methods have been developed and used. Among them, the differential pressure type using orifice and the direct doppler type using ultrasonic waves are the most commonly used. However, these flow rate measurement methods have limitations in installation, conditions and status of the measuring part, etc. To solve this problem, we have studied a new technique for measuring flow rate from scratch. In this paper, we have devised a technique to estimate the flow rate using an average moving velocity of large-scale eddy in turbulence that occurs in the piping flow field. The velocity of the large-scale eddy can be measured using the pressure fluctuation signals on the inner surface of the pipe. To estimate the flow rate, at first a cross-correlation function is applied to the two pressure fluctuation signals located at different positions in the down stream for calculating the time delay between the moving eddies. In order to validate the proposed flow rate estimation method, CFD analyses for the internal turbulence flow in pipe are conducted with a fixed flow condition, where the pressure fluctuation signals on the pipe inner surface are simulated. And then the average flow velocity of the large scale eddy is to be estimated. The estimated flow velocity is turned out to be similar to the fixed (known) flow rate.

• 한국음향학회지
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• 제14권2호
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• pp.50-61
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• 1995

본 논문에서는 음성 신호가 가지고 있는 중요한 특성을 유지하면서 발음 속도만을 변화시키는 시간축 변환 방법을 범용 디지탈 신호 처리 프로세서를 이용하여 실시간으로 구현하였다. 음성 신호 시간축 변환은 음성 신호의 발음 속도만을 변화시키기 때문에, 입력 신호와 변환 신호간의 시간적 차이가 발생하여 실시간 처리가 불가능하다. 본 논문에서는 이러한 입력, 변환 신호간의 시간차를 해결하기 위해서, 카세트 테이프 레코더의 모터 회전 속도를 조절하는 것과 같은 물리적 시간축 변환으로, 입력 음성 신호를 느리게 또는 빠르게 변환시켜 그 신호를 실시간 시스템의 입력으로 사용하였다. 카세트 레코더의 주행 속도만을 조절하는 물리적 변환은 원 신호의 피치 정보를 왜곡시켜, 원 음성의 특성을 변화시키기 때문에, 본 연구에서는 FIR 필터를 이용한 피치 보정 기법으로 왜곡된 신호를 원신호로 복원한 후, SOLA 시간축 변환 방법을 이용하여, 복원된 신호를 카세트 레코더의 모터 속도에 맞추어 시간축으로 변환하는 시스템을 실시간으로 구현하였다. 구현된 알고리듬으로 음성 신호를 시간축으로 변환하는 실험에서, 16비트 해상도를 가진 ADSP2101 프로세서로 구현한 결과와 컴퓨터 시뮬레이션 결과를 비교할 때 평균 구간 신호 대 오차비가 대략 20dB로 두 결과가 거의 유사함을 알 수 있었다.

• Journal of Biosystems Engineering
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• 제33권6호
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• pp.410-415
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• 2008

On-line monitoring of fresh tomato paste processing was done using two radio frequency (RF) sensors resonant at 85 and 110 MHz. Fresh tomato juice with soluble solid content of about $5^{\circ}Brix$ was evaporated up to $23^{\circ}Brix$ and diluted down to about $5^{\circ}Brix$ again with a pilot scale evaporator. The RF sensors were installed in a processing pipe and monitored. The pastes at a specific $^{\circ}Brix$ level were sampled and analyzed for physical properties such as soluble solid content and viscosity. The relationships between sensor outputs and measured physical properties were analyzed. Analysis results showed RF sensor is feasible to apply on-line monitoring of tomato paste processing.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2977-2982
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• 2007

Feedwater heaters of many nuclear power plants have recently experienced severe wall thinning damage, which will increase as operating time progresses. Several nuclear power plants in Korea have experienced wall thinning damage in the area around the impingement baffle - installed downstream of the high pressure turbine extraction steam line - inside number 5A and 5B feedwater heaters. At that point, the extracted steam from the high pressure turbine is two phase fluid at high temperature, high pressure, and high speed. Since it flows in reverse direction after impinging the impingement baffle, the shell wall of the number 5 high pressure feedwater heater may be affected by flow-accelerated corrosion. This paper describes the comparisons between the numerical analysis results using the FLUENT code and the down scale experimental data which effect on disclosing of the shell wall thinning of the high pressure feedwater heaters by porous plate.