• 센서학회지
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• 제29권6호
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• pp.382-387
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• 2020

Hydrogen (H₂) is considered as a new clean energy resource for replacing petroleum because it produces only H₂O after the combustion process. However, owing to its explosive nature, it is extremely important to detect H₂ gas in the ambient atmosphere. This has triggered the development of H₂ gas sensors. 2-dimensional (2D) graphene has emerged as one of the most promising candidates for chemical sensors in various industries. In particular, graphene exhibits outstanding potential in chemoresistive gas sensors for the detection of diverse harmful gases and the control of indoor air quality. Graphene-based chemoresistive gas sensors have attracted tremendous attention owing to their promising properties such as room temperature operation, effective gas adsorption, and high flexibility and transparency. Pristine graphene exhibits good sensitivity to NO₂ gas at room temperature and relatively low sensitivity to H₂ gas. Thus, research to control the selectivity of graphene gas sensors and improve the sensitivity to H₂ gas has been performed. Noble metal decoration and metal oxide decoration on the surface of graphene are the most favored approaches for effectively controlling the selectivity of graphene gas sensors. Herein, we introduce several strategies that enhance the sensitivity of graphene gas sensors to H₂ gas.

• The Journal of Asian Finance, Economics and Business
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• 제9권2호
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• pp.185-191
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• 2022

The purpose of this research is to see if liquidity, non-performing assets, sensitivity, and efficiency have an impact on the profitability and capital of Indonesian state-owned banks. A random sample of public banks was used in this study. The data was collected from the first quarter of 2014 to the fourth quarter of 2019. Purposive sampling was used as the sampling technique. According to the findings of this study, liquidity (LDR) had a significant positive effect on capital but had no significant effect on profitability. Productive asset quality as proxied by the ACA and NPL ratios did not affect profitability or capital. As for the sensitivity ratio, which was proxied by the ratio of NOP and IRR, there were differences in behavior. Sensitivity had no significant impact on profitability or capital, while NOP had a significant positive impact on capital but not on profitability. In terms of efficiency, both OER and FBIR had a significant effect on profitability and capital, although in different directions. OER has a significant negative impact on both profitability and capital. Fee-based income (FBIR) had a significant positive impact on capital, but it had the opposite effect on profitability.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4296-4309
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• 2022

Mesh and turbulence model sensitivity analyses have been performed on computational fluid dynamics simulations executed with Hydra and ANSYS Fluent for a single CANadian Deuterium Uranium (CANDU) 37M nuclear fuel bundle placed within a standard pressure tube. The goal of this work was to perform a methodical analysis to objectively determine an appropriate mesh and to gauge the sensitivity of different turbulence models for CANDU subchannel flow under isothermal conditions. The boundary conditions and material properties are representative of normal operating conditions in a high-powered channel of the Darlington Nuclear Generating Station. Four meshes were generated with ANSYS Workbench Meshing, ranging from 22 to 84 million cells, and analyzed here to determine an appropriate level of mesh resolution and quality. Five turbulence models were compared in the turbulence model sensitivity analysis: standard k - ε, RNG k - ε, realizable k - ε, SST k - ω, and the Reynolds Stress Model. The intent of this work was to gain confidence in mesh generation and turbulence model selection of a single bundle to inform the decision making of subsequent investigations of an entire fuel channel containing a string of twelve bundles.

• 대한전기학회논문지:전력기술부문A
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• 제48권12호
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• pp.1589-1598
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• 1999

Conventional MSE or PSNR based methods for objective picture quality assessment of moving picture coder are not well correlated with subjective human evaluation. In recent years, the design of better objective quality assessment has attracted much intention and several picture quality metrics based on the properties of Human Visual System has been proposed. This paper proposes new metric which is appropriate for objective picture quality assessment of block based moving picture coder by considering frequency sensitivity, inter-intra channel masking and several distortion artifacts caused by block based coding. The experimental results show that the proposed method is good correlated with subjective assessment.

• 품질경영학회지
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• 제36권4호
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• pp.77-86
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• 2008

Due to the rapid growth in automated testing and manufacturing systems, screening inspection becomes very attractive. In this paper, we investigate the effects of limited capacity on screening inspection using a surrogate variable. The model is developed under the assumption that the reprocessed and nonreprocessed items are produced by the same manufacturing process and therefore their quality characteristics are independently and identically distributed. Profit models are constructed which involve four price/cost components; selling price, cost incurred by imperfect quality, reprocessing and quality inspection costs. Methods of finding the optimal screening limits are presented, and a numerical example is given. Sensitivity analyses are also performed to study the effect of a process standard deviation on this model.

• International journal of advanced smart convergence
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• 제1권1호
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• pp.6-13
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• 2012

An improved algorithm for image quality assessment is presented. First a simple model of human visual system, consisting of a nonlinear function and a 2-D filter, processes the input images. This filter has one user-defined parameter, whose value depends on the reference image. This way the algorithm can adapt to different scenarios. In the next step the average value of locally computed correlation coefficients between the two processed images is found. This criterion is closely related to the way in which human observer assesses image quality. Finally, image quality measure is computed as the average value of locally computed correlation coefficients, adjusted by the average correlation coefficient between the reference and error images. By this approach the proposed measure differentiates between the random and signal dependant distortions, which have different effects on human observer. Performance of the proposed quality measure is illustrated by examples involving images with different types of degradation.

• 한방비만학회지
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• 제4권1호
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• pp.125-137
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• 2004

Objective: The purpose of this study is to investigate how to use the Quality of Life(QoL) of obesity and to study the report cases which measure QoL on obesity. Method: This study investigate the definition of Health-related Quality of Life(HRQoL), the measurement of Health-related Quality of Life, and the papers of Health-related Quality of Life on obesity through the books and medicine journals of HRQoL and obesity. Conclusions: 1. The QoL includes role functional ability, the degree and quality of social and community interaction, psychological state, somatic feeling, and life satisfaction than personal health and social well-being. 2. The investigator needs to evaluate the reliability, validity and sensitivity of the scale, and the appropriateness of the instrument for the target population When he decides measurement. 3. The investigator have the well-drilled supporter or himself managed the data and study population to prevent missing data. 4. The investigator should decide which is needed on obesity a obesity-specific or broad-ranging instrument, or both.

• 한국의류학회지
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• 제32권8호
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• pp.1274-1285
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• 2008

The purpose of this study is to investigate influences of perceived price dimensions and store attributes on store choice behavior. Three major retail formats, department store, discount store, and internet shopping mall in retail industry were compared with respect to store attributes and intention to purchase fashion products. Data were obtained from 427 consumers aged 25-49 years old. The results were as follows. (1) Multidimensional aspects of the price construct were identified: price-quality schema, prestige sensitivity, price mavenism, value consciousness, price consciousness, and sales proneness. (2) Store attributes included product assortment, quality per price (Q/P), service, and symbolic image in general. However, store attribute factors of three retail formats consisted of slightly different items. Department stores presented the highest level of mean scores on product quality, customer service, and symbolic images, while internet mall exhibited highest on product variety, information comparison, and quality per price. (3) Respondents presented high level of intention to purchase fashion products at internet mall, department store, and discount store in that order. (4) Purchase intention at department store was predicted by Q/P, service, symbolic image, prestige sensitivity, product assortment, clothing consumption, and age in order. Purchase intention at discount store was influenced by assortment & Q/P, symbolic image, clothing consumption, and sales proneness, whereas internet mall was predicted by product assortment, Q/P, service, price mavenism, and price-quality schema.

• 한국수자원학회논문집
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• 제35권4호
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• pp.385-395
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• 2002

하천에서의 수질변동을 예측하기 위해 FOEA(First-Order Error-Analysis)와 Monte Carlo 모의를 적용한 추계학적 모형을 개발하였다. 영향메트릭스(Influential matrix)를 이용한 민감도 분석을 실시하여 주요 반응계수를 결정하였고, BFGS(Broyden-Fletcher-Goldfarb-Shanno) 최적화 기법을 사용하여 주요 반응계수 값을 산정하였다. 본 모형을 확정론적 수질해석과 동일한 실제 하도구간에 적용하여 추계학적 수질해석을 실시하였고, 그 결과는 확정론적 해석결과와 잘 일치하였다. 유량과 수질, 반응계수 등에 포함된 불확실도가 하류단의 불확실도에 끼치는 영향을 산정하기 위해 상류단과 지류의 유량 및 수질에 대한 불확실도, 그리고 반응계수의 불확실도에 대한 분석과정이 모형에 포함되었다. 모의수행 결과로부터 각 변수들이 가지고 있는 불확실도가 총 불확실도에 끼치는 영향에 대한 기여도를 산정 할 수 있었다.

• 한국임상수의학회지
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• 제39권3호
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• pp.114-120
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• 2022

The purpose of this study is to examine the status of quality control using multipurpose phantom of ultrasound equipment used in hospital of veterinary college in South Korea by using ATS-539 multipurpose phantom so as to examine quantitative and objective new image evaluation method. Specialists discussed and analyzed multipurpose phantom images acquired by using convex transducer of 10 ultrasound imaging devices, currently used in 9 veterinary colleges, at 4.0-6.0 MHz. Total 8 items that can be measured with ATS-539 multipurpose phantom including dead zone, vertical and horizontal measurement, axial/lateral resolution, sensitivity, focal zone, functional resolution and gray scale/dynamic range were evaluated. For qualitative evaluation, valid decisions were made based on dead zone, axial/lateral resolution, and gray scale/dynamic range which are resolution index, and coefficient of variation (COV) and blind referenceless image spatial quality evaluator (BRISQUE) were found to increase objectivity. As a result of experiment, all the targeted ultrasonic devices were found appropriate from qualitative evaluation items of dead zone, axial/lateral resolution, and gray scale/dynamic range. In other evaluation items, they were found to be appropriate from focal zone and vertical measurement of quantitative evaluation while inappropriate from horizontal measurement, sensitivity, and functional resolution. COV value was 0.12 ± 0.04, and BRISQUE value was 47.77 ± 2.77, both analysis results show that the noise level of all ultrasonic devices was located within tolerance range. Upon image examination using ATS-539 multipurpose phantom, they were 100% appropriate with inspection standards of dead zone, axial/lateral resolution, and gray scale/dynamic range, and besides, focal zone and functional resolution can be used as evaluation items. In the field of veterinary medicine, 8 standard items using ATS-539 multipurpose phantom and image evaluation items using COV and BRISQUE can be used as standards for quality control of ultrasonography machine.