• 제목/요약/키워드: critical means

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Application of Remote Sensing and GIS to the evaluation of riparian buffer zones

  • Ha, Sung-Ryong;Lee, Seung-Chul;Ko, Chang-Hwan;Seo, Se-Deok;Jo, Yun-Won
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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    • pp.436-440
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    • 2006
  • Diffuse pollution has been considering as a major source of the quality deterioration of water resources. The establishment of riparian vegetation strips of buffers along those areas of water bodies is used to reduce the threat of diffuse pollution. Remote sensing offers a means by which critical areas could be identified, so that subsequent action toward the establishment of riparian zones can be taken. Even though the principal purpose of this research comes from the feasibility of the imagery of KOMPSAT-2 satellite, Landsat TM satellite data, which has 7 bands, are used to characterize the land cover for the study area on the behalf of KOMPSAT-2. This investigation focuses on the assessment of the existing riparian buffer zones for a portion of the upper Geum river watershed from the viewpoint of pollution mitigation by riparian vegetation strip establishment. Through comparing the delineation of riparian buffer zones developed with the existing zones established by the government, we can find the critical distortion points of the existing riparian buffer zone.

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Diffusion of CO2 Molecules in Polyethylene Terephthalate/Polylactide Blends Estimated by Molecular Dynamics Simulations

  • Liao, Li-Qiong;Fu, Yi-Zheng;Liang, Xiao-Yan;Mei, Lin-Yu;Liu, Ya-Qing
    • Bulletin of the Korean Chemical Society
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    • 제34권3호
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    • pp.753-758
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    • 2013
  • Molecular dynamics (MD) simulations have been used to study the diffusion behavior of small gas molecules ($CO_2$) in polyethylene terephthalate (PET)/polylactide (PLA) blends. The Flory-Huggins interaction parameters (${\chi}$) determined from the cohesive energy densities are smaller than the critical value of Flory-Huggins interaction parameters (${\chi}_{critical}$), and that indicates the good compatibility of PET/PLA blends. The diffusion coefficients of $CO_2$ are determined via MD simulations at 298 K. That the order of diffusion coefficients is correlated with the availably fractional free volume (FFV) of $CO_2$ in the PET/PLA blends means that the FFV plays a vital role in the diffusion behavior of $CO_2$ molecules in PET/PLA blends. The slopes of the log (MSD) as a function of log (t) are close to unity over the entire composition range of PET/PLA blends, which confirmes the feasibility of MD approach reaches the normal diffusion regime of $CO_2$ in PET/PLA blends.

간호학생의 임상수행능력에 영향을 미치는 요인 (The Influencing Factors on Clinical Competence of Nursing Students)

  • 양진주
    • 한국간호교육학회지
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    • 제15권2호
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    • pp.159-165
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    • 2009
  • Purpose: The purpose of this study was to identify clinical competence and to analyze influencing factors on clinical competence for second year college nursing students. Methods: The data were collected from 183 students by means of self reported questionnaires with clinical competence, satisfaction of clinical practice experience, critical thinking disposition, and self-directed learning, on June 18th 2007 and June 25th 2008. Results: The influencing factors on clinical competence of nursing students were satisfaction of clinical practice experience and critical thinking disposition. The more adaptable a student's major was, the higher the clinical competence and satisfaction of clinical practice experience. The score of self-directed learning was the highest in the well adapted group of a major. For clinical competence categories, the level of basic nursing was the highest followed by psychosocial nursing, patient education, nursing process, monitoring and patient physical assessment. The level of direct nursing care was the lowest among nursing students. Conclusion: In conclusion, results of this study suggest that constructing a cooperative system between colleges and educational hospitals, intensifying preceptors' and professors' clinical instruction, and developing a multimedia learning module and practice using simulators or standardized patient care is necessary to promote clinical competence of nursing students.

말초 정맥주사를 통해 비항암제 발포성 약물을 투약한 성인 환자의 일혈 발생과 위험요인 (Factors Related to Extravasation of Non-chemotherapy Vesicant Drugs in Peripheral Vein Catheters)

  • 이종민;이주희;장연수;김연희
    • 중환자간호학회지
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    • 제11권2호
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    • pp.11-20
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    • 2018
  • Purpose : This study aimed to investigate the incidence of intravenous extravasation and the risk factors associated with the use of peripheral intravenous catheters in adults. Method : This prospective observational study included 203 adult patients admitted to the general ward who received non-chemotherapy vesicant drug infusion treatments. Data were analyzed using frequencies, percentage, means, standard deviations, and odds ratios (ORs) from multiple logistic regressions. Results : The incidence of extravasation was 43.3%. Risk factors for intravenous extravasation included continuous injections (OR=5.35, 95% CI [1.38, 20.83]), and parenteral nutrition (OR=3.53, 95% CI [1.43, 8.73]). Conclusion : The present findings revealed that gastrointernal medicine problems, continuous injection, and parenteral nutrition were related to intravenous extravasation. Further research is necessary to reduce the incidence of extravasation related to peripheral intravenous catheterization in adults, and to prevent secondary complications. Finally, patients should be provided appropriate and continuous care based on the type of intravenous infusion.

Comparison of hot spot stress evaluation methods for welded structures

  • Seo, Jung-Kwan;Kim, Myung-Hyun;Shin, Sang-Beom;Han, Myung-Soo;Park, June-Soo;Mahendr, Mahen;Lee, Jae-Myung
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제2권4호
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    • pp.200-210
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    • 2010
  • In this paper, different evaluation methods of Hot Spot Stresses (HSS) have been applied to four different welded structure details in order to compare them and to illustrate their differences. The HSSs at failure-critical locations were calculated by means of a series of finite element analyses. There was good overall agreement between calculated and experimentally determined HSS on the critical locations. While different methods and procedures exist for the computation of the structural hot-spot stress at welded joints, the recommendations within the International Institute of Welding (IIW) guideline concerning the 'Hot Spot Stress' approach were found to give good reference stress approximations for fatigue-loaded welded joints. This paper recommends and suggests an appropriate finite element modeling and hot spot stress evaluation technique based on round-robin stress analyses and experimental results of several welded structure details.

가족면회가 심장 중환자실 환자와 가족의 스트레스 반응에 미치는 효과 (The Effect of Family Visits on Stress Responses of Patients and Their Families in the Cardiac Intensive Care Unit)

  • 박찬금;김혜순;이명희
    • 중환자간호학회지
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    • 제3권1호
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    • pp.41-51
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    • 2010
  • Purpose: The purpose of this study was to identify the effects of family visits upon the stress response of patients and their families, Methods: This study was the interrupted time series design, The subjects consisted of 197 patients and 197 family members in the cardiac intensive care unit of S Hospital in Bucheon. Physiological stress responses such as blood pressure, heart rates, respiration rates, and oxygen saturation were measured using HP monitors. VAS was used to measure the emotional stress. Collected data was analyzed using repeated measure ANOVA, t-test by SPSS 17.0 statistical program. Results: The family visits did not change patients' blood pressure, pulse rate, respiration rate and oxygen saturation, However the anxiety level of patients and their family members were decreased significantly during family visits. Furthermore, 30-minute family visit reduced more effectively patient's anxiety than 15-minute family visit. Conclusion: Family visits need to be used as a means of nursing intervention to ease the emotional stress of patients and their families. In addition, increasing of visiting time should be considered.

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Thermo- and Acid/base-induced Spectral Switching of a Poly(N-isopropylacrylamide) Copolymer Containing Benzopyran-based D-π-A type Dye Units

  • Lee, Eun-Mi;Gwon, Seon-Yeong;Ji, Byung-Chul;Kim, Sung-Hoon
    • 한국염색가공학회지
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    • 제22권3호
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    • pp.181-186
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    • 2010
  • A thermoresponsive poly(NIPAM-co-dye) labeled with benzopyran-based D-$\pi$-A type dye was prepared by typical radical copolymerization. It can be also constructed a acid/base-induced molecular switch by modulation of intramolecular charge transfer with protonation/deprotonation. The lower critical solution temperature behavior was investigated by means of UV-vis spectroscopy which allows the measurement of the phase transition from $25^{\circ}C$ to $45^{\circ}C$ in aqueous DMSO solution. The morphology of the internal microstructure of the poly(NIPAM-co-dye) hydrogel was observed by scanning electron microscopy. The reversible switch could be obtained by thermal and acid/base stimuli.

Blockage effects on aerodynamics and flutter performance of a streamlined box girder

  • Li, Yongle;Guo, Junjie;Chen, Xingyu;Tang, Haojun;Zhang, Jingyu
    • Wind and Structures
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    • 제30권1호
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    • pp.55-67
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    • 2020
  • Wind tunnel test is one of the most important means to study the flutter performance of bridges, but there are blockage effects in flutter test due to the size limitation of the wind tunnel. On the other hand, the size of computational domain can be defined by users in the numerical simulation. This paper presents a study on blockage effects of a simplified box girder by computation fluid dynamics (CFD) simulation, the blockage effects on the aerodynamic characteristics and flutter performance of a long-span suspension bridge are studied. The results show that the aerodynamic coefficients and the absolute value of mean pressure coefficient increase with the increase of the blockage ratio. And the aerodynamic coefficients can be corrected by the mean wind speed in the plane of leading edge of model. At each angle of attack, the critical flutter wind speed decreases as the blockage ratio increases, but the difference is that bending-torsion coupled flutter and torsional flutter occur at lower and larger angles of attack respectively. Finally, the correction formula of critical wind speed at 0° angle of attack is given, which can provide reference for wind resistance design of streamlined box girders in practical engineering.

A Novel System for Detecting Adult Images on the Internet

  • Park, Jae-Yong;Park, Sang-Sung;Shin, Young-Geun;Jang, Dong-Sik
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제4권5호
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    • pp.910-924
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    • 2010
  • As Internet usage has increased, the risk of adolescents being exposed to adult content and harmful information on the Internet has also risen. To help prevent adolescents accessing this content, a novel detection method for adult images is proposed. The proposed method involves three steps. First, the Image Of Interest (IOI) is extracted from the image background. Second, the IOI is distinguished from the segmented image using a novel weighting mask, and it is determined to be acceptable or unacceptable. Finally, the features (color and texture) of the IOI or original image are compared to a critical value; if they exceed that value then the image is deemed to be an adult image. A Receiver Operating Characteristic (ROC) curve analysis was performed to define this optimal critical value. And, the textural features are identified using a gray level co-occurrence matrix. The proposed method increased the precision level of detection by applying a novel weighting mask and a receiver operating characteristic curve. To demonstrate the effectiveness of the proposed method, 2850 adult and non-adult images were used for experimentation.

Bicycle 모델을 이용한 4륜 조향 차량의 동력학 해석 (Linearized Dynamic Analysis of a Four-Wheel Steering Vehicle)

  • 이영화;김석일;서명원;손희성;김성하
    • 한국자동차공학회논문집
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    • 제2권5호
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    • pp.101-109
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    • 1994
  • Recently, four-wheel steering systems have been developed and studied as one of the latest automotive technologies for improving the handling characteristics of a vehicle. In much of the proposed four-wheel steering systems, the side slip angle at the vehicle's center of gravity is maintained at zero. This approach allows the greater maneuverability at low speed by means of counter-phase rear steering and the improved stability at high speed through same-phase rear steering. In this paper, the effects of several four-wheel steering systems are studied and discussed on the responsiveness and stability of the vehicle by using the linear analysis. Especially, the effects of the cornering stiffnesses of both front and rear wheels are investigated on the yaw velocity gain and critical speed of the vehicle.

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