• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제22권4호
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• pp.37-45
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• 2016

Purpose: The purpose of this paper is to analyze a sample of single corridor, pod type and composite type of ICUs in terms of patient visibility, spatial configurations and nurse walking distance focused on Korean cases. Methods: The measures of static visibility were used to quantify the patient visibility (upper third part of the patient bed) from the nurse station. The measure of space programme and area distribution (patient zone percentage, staff zone percentage, circulation zone percentage, corridor length per bed, distance from nurse station (NS) to patient bed and departmental gross square meter (DGSM) per patient bed) were calculated by using AutoCAD and MS Excel programs. In the second step of analysis the values of space distribution were compared among the three type of ICUs as well as the nurse walking distance, DGSM per bed and gross factor. in the third step of analysis regression analysis was conducted for the possible correlation between visibility and space programme and area distribution factors as well as nurse walking distance factors. Results: (1) It was found that on average composite type unit offer highest value of patient visibility followed by pod type, while single corridor type unit offers the minimum value of patient visibility among the three plan typologies. (2) Average patient visibility and DGSM per bed shows a strong positive correlation ($r^2=0.75$) and p=0.026. (3) Average patient visibility and average distance from NS has a strong negative correlation ($r^2=0.78$), and P=0.02. (4) On average composite type unit offer the minimum walking distance from NS (7.22 meter) followed by pod type unit (8.35 meter) and single corridor (9.76 meter). (5) Maximum distance from NS was noted in single corridor (18.19 meter) followed by pod type unit (15.14 meter) and Composite type unit (11.1 meter). Implications: This study may contribute to the visibility analysis of existing and future ICU design in Korea to achieve maximum patient visibility and reduced nurse walking distance.

• 한국항공우주학회지
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• 제38권5호
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• pp.414-420
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• 2010

본 연구에서는 천음속 날개/동체 모텔에 대한 축소모델 (Reduced Order Model; ROM)의 정확성을 검증하고, Proper Orthogonal Decomposition(POD)을 이용한 최적설계를 통해 그 효율성을 검토하였다. full order 공력해석을 통한 Snapshot을 추출하기 위해 삼차원 오일러 방정식을 이용하였으며, 이들 Snapshot들을 통해 날개/동체 모델 주위 유동장의 거동을 모사하는 POD의 기저벡터를 계산 하였다. 이러한 과정을 거쳐 구축된 축소모텔은 6개의 Case들로 검증하였으며, 그 결과 ROM을 이용해 관심영역에 대한 유동장의 예측을 할 수 있다는 것을 확인하였다. 그리고 ROM을 통한 날개/동체 모델의 최적설계를 수행 하였으며, 그 결과는 반응면모델 (Response Surface Model; RSM)을 이용한 최적설계 결과와 비교 하였다. 이를 통해 ROM을 바탕으로한 최적설계가 RSM을 이용한 것보다 효율적임을 확인하였다.

• Transactions on Electrical and Electronic Materials
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• 제17권6호
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• pp.341-350
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• 2016

The current study is dedicated to design a novel coordinated controller to effectively increase power system rotor angle stability. In doing so, the coordinated design of an AVR (automatic voltage regulator), PSS2B, and TCSC (thyristor controlled series capacitor)-based POD (power oscillation damping) controller is proposed. Although the recently employed coordination between a CPSS (conventional power system stabilizer) and a TCSC-based POD controller has been shown to improve power system damping characteristics, neglecting the negative impact of existing high-gain AVR on the damping torque by considering its parameters as given values, may reduce the effectiveness of a CPSS-POD controller. Thus, using a technologically viable stabilizer such as PSS2B rather than the CPSS in a coordinated scheme with an AVR and POD controller can constitute a well-established design with a structure that as a high potential to significantly improve the rotor angle stability. The design procedure is formulated as an optimization problem in which the ITSE (integral of time multiplied squared error) performance index as an objective function is minimized by employing an IPSO (improved particle swarm optimization) algorithm to tune adjustable parameters. The robustness of the coordinated designs is guaranteed by concurrently considering some operating conditions in the optimization process. To evaluate the performance of the proposed controllers, eigenvalue analysis and time domain simulations were performed for different operating points and perturbations simulated on 2A4M (two-area four-machine) power systems in MATLAB/Simulink. The results reveal that surpassing improvement in damping of oscillations is achieved in comparison with the CPSS-TCSC coordination.

• 한국작물학회지
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• 제45권2호
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• pp.97-102
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• 2000

This experiment was conducted to investigate the changes of harvest index and the relationship between harvest index and yield determination factors by different planting times in the determinate soybean cultivars, Shinpaldal and Danbaeg. Optimum planting were 23 May in 1995 and 1996. Late planting were 13 June in 1995 and 6 June in 1996. Growth period from planting to physiological maturity (R7) was shortened as planting time was delayed in two cultivars due to shortening of reproductive growth period in Shinpaldal, and of vegetative growth period in Danbaeg. Stem weight was distinctly decreased in late planting compared to optimum planting, but seed weight of both cultivars was not different between planting times. Also, seed number per pod and harvest index were significantly increased in late planting and the high correlation was found between two factors. It was suggested that increase of harvest index in late planting would be related with high assimilate use efficiency due to increase of sink capacity. The results of correlation and principal component analysis for yield determination factors showed that main factor on yield determination was pod number per plant at R5 stage associated with dry matter accumulation during early reproductive growth period, seed number per pod and harvest index were the second factor, and one hundred seed weight was the third factor. The result of this experiment indicated that yield determination in soy-bean was dependent mainly on pod number per plant related to dry matter accumulation by early reproductive growth period, and the increase of seed number per pod and harvest index could compensate for yield decrease by shortening of vegetative growth period in late planting. Such result suggests that optimum planting date can be delayed from mid May to early June in improved soybean cultivars in Korea.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.87-90
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• 2005

The FORMOSAT-3/COSMIC mission is a micro satellite mission to deploy a constellation of six micro satellites at low Earth orbits. The final mission orbit is of an altitude of 750-800 lan. It is a collaborative Taiwan-USA science experiment. Each satellite consists of three science payloads in which the GPS occultation experiment (GOX) payload will collect the GPS signals for the studies of meteorology, climate, space weather, and geodesy. The GOX onboard FORMOSAT -3 is designed as a GPS receiver with 4 antennas. The fore and aft limb antennas are installed on the front and back sides, respectively, and as well as the two precise orbit determination (POD) antennas. The precise orbit information is needed for both the occultation inversion and geodetic research. However, the instrument associated errors, such as the antenna phase center offset and even the different cable delay due to the geometric configuration of fore- and aft-positions of the POD antennas produce error on the orbit. Thus, the focus of this study is to investigate the impact of POD antenna parameter on the determination of precise satellite orbit. Furthermore, the effect of the accuracy of the determined satellite orbit on the retrieved atmospheric and ionospheric parameters is also examined. The CHAMP data, the FORMOSAT-3 satellite and orbit parameters, the Bernese 5.0 software, and the occultation data processing system are used in this work. The results show that 8 cm error on the POD antenna phase center can result in ~8 cm bias on the determined orbit and subsequently cause 0.2 K deviation on the retrieved atmospheric temperature at altitudes above 10 lan.

• 한국임상약학회지
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• 제28권1호
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• pp.17-23
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• 2018

Objective: Opioid analgesics, for postoperative pain management, are an indispensable group of medication; however, they also have a variety of adverse drug reactions (ADR). Multimodal methods, combining non-opioid analgesics with opioid analgesics, have been investigated to increase the effects of analgesics and reduce ADR with opioid-sparing effects. The purpose of this study was to compare the effects of patient-controlled analgesia (PCA) with fentanyl alone, and PCA with fentanyl and intravenous (i.v.) propacetamol to determine the effects of pain control, cumulative opioid usage, and opioid ADR. Methods: The subjects were patients who underwent total knee arthroplasty at the Seoul Veterans hospital from January 1, 2015 to December 31, 2016. The study period was from postoperative day 0 (POD0) to day 3 (POD3), and the retrospective study was conducted using electronic medical records. Results: Pain severity was significantly low at POD1 (p = 0.017), POD2 (p = 0.003), and POD3 (p = 0.002) in the multimodal group. The fentanyl only group frequently reported both moderate and severe pain at a statistically significant level. This was consistent with the analysis of the pro re nata (PRN) intramuscular analgesia usage at the time of numerical rating scale (NRS) 4 and above. The opioid-sparing effect confirmed that the average opioid dose equivalent to i.v. morphine dose was 9.4 mg more than that used for the multimodal group in the fentanyl only group. The ADRs and length of stay between the two groups were not statistically different. Conclusion: The results of this study suggest that the combination therapy of fentanyl and i.v. propacetamol is superior to fentanyl monotherapy.

• Nuclear Engineering and Technology
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• 제54권1호
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• pp.36-48
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• 2022

As a valid numerical method to obtain a high-resolution result of a flow field, computational fluid dynamics (CFD) have been widely used to study coolant flow and heat transfer characteristics in fuel rod bundles. However, the time-consuming, iterative calculation of Navier-Stokes equations makes CFD unsuitable for the scenarios that require efficient simulation such as sensitivity analysis and uncertainty quantification. To solve this problem, a reduced-order model (ROM) based on proper orthogonal decomposition (POD) and machine learning (ML) is proposed to simulate the flow field efficiently. Firstly, a validated CFD model to output the flow field data set of the rod bundle is established. Secondly, based on the POD method, the modes and corresponding coefficients of the flow field were extracted. Then, an deep feed-forward neural network, due to its efficiency in approximating arbitrary functions and its ability to handle high-dimensional and strong nonlinear problems, is selected to build a model that maps the non-linear relationship between the mode coefficients and the boundary conditions. A trained surrogate model for modes coefficients prediction is obtained after a certain number of training iterations. Finally, the flow field is reconstructed by combining the product of the POD basis and coefficients. Based on the test dataset, an evaluation of the ROM is carried out. The evaluation results show that the proposed POD-ROM accurately describe the flow status of the fluid field in rod bundles with high resolution in only a few milliseconds.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.31-37
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• 2011

대형 고체로켓에 존재하는 그레인간 인히비터로 인해 발생하는 유동과 압력의 교란 현상을 조사하기 위해 Large Eddy Simulation과 Proper Orthogonal Decomposition(POD) 기법을 적용하였다. 해석 결과는 실험 결과와 유사하며 정량적 및 정성적 분석을 수행하였다. 인히비터에서 발생하는 와류(vortex)는 노즐헤드와 충돌하여 발생하는 음향가진(acoustic source)에 영향을 받아 주기적으로 발생하는 것을 확인하였다. 또한 3차원 해석 결과 와류가 노즐헤드에 충돌하는 과정에서 유동이 불균형한 형상으로 분해되면서 노즐 출구 유동이 회전하여 롤 토크를 유발함을 확인 하였다.

• 한국가시화정보학회지
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• 제6권2호
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• pp.14-19
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• 2008

In this paper, the recirculation flow motion and mixing characteristics driven by air bubble flow in a rectangular water tank is studied. The Time-resolved PIV technique is adopted for the quantitative visualization and analysis. 532 nm Diode CW laser is used for illumination and orange fluorescent particle images are acquired by a PCO 10bit high-speed camera. To obtain clean particle images, 545 nm long pass optical filter and an image intensifier are employed and the flow rates of compressed air is changed from 2 l/min to 4 l/min at 0.5 MPa. The recirculation and mixing flow field is further investigated by the POD analysis technique. It is observed that the large scale counterclockwise rotation and main vortex is generated in the upper half depth from the free surface and one quarter width from the sidewall. When the flow rates are increased, the main vortex core is moved to the side and bottom wall direction.

• 한국자원식물학회지
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• 제20권6호
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• pp.504-510
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• 2007

GE interaction is the expression of differential genotypic adaptation across environments. GE interactions through different stability parameters and performance of the traits of genotypes were studied. The traits were days to maturity, pod length, number of pods/ plant, 100-seed weight and seed yield/plant in ten soybean genotypes across five environments. Significant differences were observed for genotypes, environments and GE interactions. Stability analysis after Eberhart and Russell's model suggested that the genotypes used in this study were all more or less responsive to environmental changes. Most of the genotypes perform better in Env.3. Based on phenotypic indices(Pi), regression ($S^2di$) genotype Garurab was found fairly stable for days to maturity. BS-23 and G-2120 may be considered as stable genotype for pod length. All the genotypes except G-2120 showed that the genotypes were relatively unstable under environmental fluctuation for the number of pod/plant. Genotype BS-23 was found most stable among all the genotypes for 100-seed weight. BS-3 and Gaurab was the most stable and desirable genotypes for seed yield in soybean.