• International Journal of Computer Science & Network Security
• /
• 제21권12spc호
• /
• pp.556-564
• /
• 2021

Numerous spatial and transform-domain-based conventional denoising algorithms struggle to keep critical and minute structural features of the image, especially at high noise levels. Although neural network approaches are effective, they are not always reliable since they demand a large quantity of training data, are computationally complicated, and take a long time to construct the model. A new framework of enhanced hybrid filtering is developed for denoising color images tainted by additive white Gaussian Noise with the goal of reducing algorithmic complexity and improving performance. In the first stage of the proposed approach, the noisy image is refined using a high-dimensional non-local means filter based on Principal Component Analysis, followed by the extraction of the method noise. The wavelet transform and SURE Shrink techniques are used to further culture this method noise. The final denoised image is created by combining the results of these two steps. Experiments were carried out on a set of standard color images corrupted by Gaussian noise with multiple standard deviations. Comparative analysis of empirical outcome indicates that the proposed method outperforms leading-edge denoising strategies in terms of consistency and performance while maintaining the visual quality. This algorithm ensures homogeneous noise reduction, which is almost independent of noise variations. The power of both the spatial and transform domains is harnessed in this multi realm consolidation technique. Rather than processing individual colors, it works directly on the multispectral image. Uses minimal resources and produces superior quality output in the optimal execution time.

• 아태비즈니스연구
• /
• 제9권4호
• /
• pp.29-47
• /
• 2018

This paper examines the relationship between diversification and financial performance of community credit unions in Korea from 2011 to 2017. To do so, I employ fixed-effects panel analyses using credit union level panel data collected from the National Credit Union Federation of Korea. This study finds evidence that business diversification is likely to lower the ratio of troubled loans, which means improving asset quality of credit unions. However, the relationship between diversification and asset quality is not linear but nonlinear, which means over-diversification would have negative effects on asset quality. Next, diversification tends to increase profitability. Specifically, although diversification results in a rise in expenditures, an increase in profits made by diversification outweighs the rise in expenditures, which contributes to profitability. Put together, diversification would be a good business strategy to improve both profitability and asset quality. Given a result that fast loan growth deteriorates asset quality, credit unions' managers might adopt the diversification strategy to enhance asset quality, and not to pursue their own objectives motivated by moral hazards.

• 한국의류산업학회지
• /
• 제23권4호
• /
• pp.480-490
• /
• 2021

Sales forecasting is crucial for many retail operations. For apparel retailers, accurate sales forecast for the next season is critical to properly manage inventory and plan their supply chains. The challenge in this increases because apparel products are always new for the next season, have numerous variations, short life cycles, long lead times, and seasonal trends. In this study, a sales forecasting model is proposed for apparel products using machine learning techniques. The sales data pertaining to outerwear items for four years were collected from a Korean sports brand and filtered with outliers. Subsequently, the data were standardized by removing the effects of exogenous variables. The sales patterns of outerwear items were clustered by applying K-means clustering, and outerwear attributes associated with the specific sales-pattern type were determined by using a decision tree classifier. Six types of sales pattern clusters were derived and classified using a hybrid model of clustering and decision tree algorithm, and finally, the relationship between outerwear attributes and sales patterns was revealed. Each sales pattern can be used to predict stock-keeping-unit-level sales based on item attributes.

• 대한수의학회지
• /
• 제61권1호
• /
• pp.7.1-7.7
• /
• 2021

The levels of aflatoxin (AFT) and ochratoxin (OCT) were assessed at different seasons in raw materials, different feed manufacture processing stages, and animal feeds in feed mills in Korea implementing the hazard analysis and critical control point (HACCP) system. Two hundred samples were collected in all four seasons from five feed mills implementing the HACCP system and examined for AFT and OCT contents. The AFT and OCT levels were analysed by using HPLC method to provide information on raw material and product stage. The AFT content of raw ingredients in the spring season was highest in corn gluten (3.84 ppb) and lowest in corn (1.82 ppb) The AFT content of corn was highest in the winter season (2.17 ppb). The content of OCT in wheat was highest in the winter season. The amounts of AFT and OCT at processing stages were higher than in the raw materials or feed. In particular, AFT content was higher in the transfer stage (3.88 ppb) than in the mixing (2.86 ppb) or filling stages (3.45 ppb) in the summer season. The means of AFT and OCT level in laying hen feed was 3.41 ppb and 1.14 ppb for broiler feed, respectively. The means of AFT and OCT level in and broiler feeds was 3.44 ppb and 1.17 ppb for broiler feed, respectively.

• Smart Structures and Systems
• /
• 제29권4호
• /
• pp.577-588
• /
• 2022

Oil refineries' Fluid Catalytic Cracking Units (FCCU) when in full operation may exhibit strong fluid dynamics caused by turbulent flow in the piping system that may induce vibrations in other mechanical and structural components of the Unity. This paper reports on the experimental-theoretical-computational program performed to get the vibration properties and the dynamic response amplitudes to find out alternative solutions to attenuate the excessive vibrations that were causing fatigue fractures in components of the bottle like reactor-regenerator of an FCC unit in operation in an existing oil refinery in Brazil. Solutions to the vibration problem were sought with the aid of a 3D finite element model calibrated with the results obtained from experimental measurements. A short description of the found solutions is given and their effectiveness are shown by means of numerical results. The solutions were guided by the concepts of structural stiffening and dynamic control performed by a nonlinear pendulum controller whose mechanical design was based on parameters determined by means of a parametric study carried out with 2D and 3D mathematical models of the coupled pendulum-structure system. The effectiveness of the proposed solutions is evaluated in terms of the fatigue life of critical welded connections.

• Geomechanics and Engineering
• /
• 제36권3호
• /
• pp.247-258
• /
• 2024

Tailings are waste materials of mining operations, consisting of a mixture of clay, silt, sand with a high content of unrecoverable metals, process water, and chemical reagents. They are usually discharged as slurry into the storage area retained by dams or earth embankments. Poor knowledge of the hydro-mechanical behaviour of tailings has often resulted in a high rate of failures in which static liquefaction has been widely recognized as one of the major causes of dam collapse. Many studies have dealt with the static liquefaction of coarse soils in saturated conditions. This research provides an extension to the case of silty tailings in unsaturated conditions. The static liquefaction resistance was evaluated in terms of stress-strain behavior by means of monotonic triaxial tests. Its dependency on the preparation method, the volumetric water content, the void ratio, and the degree of saturation was studied and compared with literature data. The static liquefaction response was proved to be dependent mainly on the preparation technique and degree of saturation that, in turn, controls the excess of pore pressure whose leading role is investigated by means of the relationship between the -B Skempton parameter and the degree of saturation. A preliminary interpretation of the static liquefaction response of Stava tailings is also provided within the Critical State framework.

• 치위생과학회지
• /
• 제19권4호
• /
• pp.220-227
• /
• 2019

Background: This descriptive study aimed to examine the relationship between the 4C core competencies and work ability among dental hygienists. Methods: From November 2018 to January 2019, data were collected-from 190 dental hygienists workong in dental clinics in Busan, Ulsan, and Gyeongsangnam province using structured questionnaires. For the general characteristics of the dental hygienists, frequency and percentage were calculated, and the level of the 4C core competencies and work ability of dental hygienists was calculated using means and standard deviations. A multiple regression analysis was conducted to analyze the effects of the 4C core competencies on work ability. Results: The mean scores for the 4C core competency levels of the dental hygienists were as follows: communication ability 3.34, critical thinking ability 3.41, creative problem-solving 3.40, and collaborative self-efficacy 3.27. Meanwhile the mean score for work ability level was 3.65. The predictive factors influencing work ability were communication ability and cooperative self-efficacy (p<0.001), and the sub-factors of critical thinking ability that affect work ability were sound conferences (p<0.01), intellectual fairness (p<0.05), intellectual enthusiasm (p<0.05), and self-confidence (p<0.001). Finally, the sub-factors of creative problem-solving ability that affect work ability were planning and execution (p<0.01) and performance evaluation (p<0.05). Conclusion: The current study showed that education programs covering the core competencies of dental hygienists, rather than the existing theoretical education program, should be developed and implemented to enhance 4C core competencies that affect work ability.

• Structural Engineering and Mechanics
• /
• 제20권5호
• /
• pp.505-526
• /
• 2005

The influence of the inter-story structural pounding on the seismic behaviour of adjacent multistory reinforced concrete structures with unequal total heights and different story heights is investigated. Although inter-story pounding is a common case in practice, it has not been studied before in the literature as far as the authors are aware. Fifty two pounding cases, each one for two different seismic excitations, are examined. From the results it can be deduced that: (i) The most important issue in the inter-story pounding is the local effect on the external column of the tall building that suffers the impact from the upper floor slab of the adjacent shorter structure. (ii) The ductility demands for this column are increased comparing with the ones without the pounding effect. In the cases that the two buildings are in contact these demands appear to be critical since they are higher than the available ductility values. In the cases that there is a small distance between the interacting buildings the ductility demands of this column are also higher than the ones of the same column without the pounding effect but they appear to be lower than the available ductility values. (iii) It has to be stressed that in all the examined cases the developed shear forces of this column exceeded the shear strength. Thus, it can be concluded that in inter-story pounding cases the column that suffers the impact is always in a critical condition due to shear action and, furthermore, in the cases that the two structures are in contact from the beginning this column appears to be critical due to high ductility demands as well. The consequences of the impact can be very severe for the integrity of the column and may be a primary cause for the initiation of the collapse of the structure. This means that special measures have to be taken in the design process first for the critically increased shear demands and secondly for the high ductility demands.

• 한국화재소방학회논문지
• /
• 제22권2호
• /
• pp.30-37
• /
• 2008

건축용 바닥재의 화재예방을 위하여 국제규격으로 정해져 있는 바닥재 시험평가 방법인 KSISO 9239-1을 이용하여 각종 바닥재에 대한 연소성 시험을 복사열 판넬 시험기를 사용하여 실시하였다. 복사열 판넬 시험기를 이용하여 각종 바닥재에 대한 화염 전파거리, 임계 열류량 그리고 연기 발생농도 측정하였다. 측정결과 바닥재의 구성 물질 별로 서로 다른 연소특성을 나타내었으며, 바닥재의 표면 재질 및 구성성분이 열 방출과 연기 발생량에 있어 중요한 영향을 미치게 된다는 것을 확인할 수 있었다. 위의 평가방법은 화재위험성을 연구하는데 중요한 인자인 임계 열류량, 연기 발생량 및 화염 전파거리를 정량적으로 평가하는 중요한 시험방법임을 알 수 있었고 국내 건축용 바닥재 화재평가 방법을 국내실정에 맞게 제정 및 적용하는 것이 적합할 것으로 판단되었다.

• 종양간호연구
• /
• 제12권3호
• /
• pp.204-212
• /
• 2012

Purpose: To investigate the effectiveness and variance of a critical pathway (CP) for laparoscopic colon resection in colon cancer patients, and nurses'satisfaction with the CP. Methods: A CP for laparoscopic colon resection was applied to the CP-group that included 50 patients, who underwent elective colon resection between March and May, 2011. The non-CP group included 51 patients who had the same operation without the CP applied from March to May, 2010. Results: The means of length of hospital stay were 11.7 and 7.3 days (p<.001) and the lengths of postoperative hospital stay were 8.6 and 5.1 days (p<.001) in the non-CP group and CP group, respectively. There was no significant difference between two groups for total healthcare costs, pain score, complications, or emergency room visits within 30 days after discharge. By examining variances of the CP, there were 162 variances and the most frequent cause was patient's condition. Nurses'satisfaction with the use of CP was favorable and the mean score of satisfaction was 3.76 on the 5 point Likert scale. Conclusion: There are clear benefits to use of CP, resulting in standardized and effective patient care. In conclusion, analysis of variance data can assist in evaluating and revising CP for optimal care and reducing variances.