• 한국분무공학회지
• /
• 제24권3호
• /
• pp.122-129
• /
• 2019

Flow uniformity in aftertreatment system is an important factor in determining uniform catalytic reaction and filtration. In this study, variety types of DOC-DPF system design were analyzed to increase flow uniformity. For this analysis, ANSYS Fluent was used with porous media setup for DOC and DPF. Turbulent flow was modeled by standard $k-{\varepsilon}$ model excepting porous media. Uniformity index was utilized to evaluate the flow uniformity quantitatively. Reference design showed low velocity region because two large vortex were generated before baffle. When radius of DOC-DPF system was increased, exhaust pressure acting on the inlet decreases and velocity distribution was shifted to one side. When inlet pipe was set to axial center of DOC-DPF system velocity distribution was symmetric. However, flow was not dissipated until the front end of DOC and showed higher uniformity index. When the volume of DOC was reduced while fixed volume of entire DOC-DPF system and baffle plate is located downstream of the DOC-DPF system, there was improvement in uniformity index.

• 대한영양사협회학술지
• /
• 제19권1호
• /
• pp.25-33
• /
• 2013

We examined the perception of volume in college students with a normal weight versus those students with obesity. College students were divided into a normal weight group (<23 body mass index, n=121) and an obese group (${\geq}23$ body mass index, n=110), The perception of volume was measured under different beverage colors (colorless, black, yellow, and blue) and cup colors (colorless, black, yellow, and blue) containing the same amount of liquid (150 ml). We found that the normal weight group perceived significantly more liquid in a cup with a blue beverage versus a colorless one. The obese group perceived significantly more liquid in a cup with a yellow or blue beverage versus a colorless one. In terms of cup color, the normal weight group perceived significantly more liquid in a black color cup compared to a blue color cup. However, there were no differences in perceived volume according to the color of cup among the obese group. There were no significant differences in the perceived volume between the normal and obese group under all conditions tested. In conclusion, beverage and cup color effects volume perception in normal weight students, while only beverage color effects volume perception in obese students. Therefore, controlling, the color of beverages and cups may help to control the consumption of drinks.

• 대한안전경영과학회지
• /
• 제12권4호
• /
• pp.255-263
• /
• 2010

The research developes short-run standardized control charts(SSCC) and short-run acceptance control charts(SACC) under the various demand patterns. The demand patterns considered in this paper are three types such as high-variety and repetitive low-volume pattern, extremely-high-variety and nonrepetitive low-volume pattern, and high-variety and extremely-low-volume pattern. The short-run standardized control charts developed by extending the long-run ${\bar{x}}$-R, ${\bar{x}}$-s and I-MR charts have strengths for practioners to understand and use easily. Moreover, the short-range acceptance control charts developed in the study can be efficiently used through combining the functions of the inspection and control chart. The weighting schemes such as Shewhart, moving average (MA) and exponentially weighted moving average (EWMA) can be considered by the reliability of data sets. The two types according to the use of control chart are presented in the short-range standardized charts and acceptance control charts. Finally, process capability index(PCI) and process performance index(PPI) classified by the demand patterns are presented.

• 응용통계연구
• /
• 제35권1호
• /
• pp.93-104
• /
• 2022

S&P 500과 RUSSELL 2000, DJIA, Nasdaq 100 4가지 미국 주가지수의 실현변동성(realized volatility, RV)을 예측하는데 있어서 사람들의 관심 지표로 삼을 수 있는 인터넷 검색량(search volume, SV) 지수와 내재변동성(implied volatility, IV)를 이용하여 LSTM 딥러닝(deep learning) 방법으로 RV의 예측력을 높이고자하였다. SV을 이용한 LSTM 방법의 실현변동성 예측력이 기존의 기본적인 vector autoregressive (VAR) 모형, vector error correction (VEC)보다 우수하였다. 또한, 최근 제안된 RV와 IV의 공적분 관계를 이용한 vector error correction heterogeneous autoregressive (VECHAR) 모형보다도 전반적으로 예측력이 더 높음을 확인하였다.

• 한국콘텐츠학회논문지
• /
• 제12권6호
• /
• pp.338-345
• /
• 2012

서구화된 식습관과 생활환경의 변화로 전립선비대증이 증가하고 있다. 하지만 진단 시 표준으로 참고할 기준이 되는 전립선 용적에 대한 연구가 부족하다. 또한 국내에서 이뤄진 연구의 대부분은 40대 이상의 중년 남성을 대상으로 하고 있다. 본 연구는 건강검진을 위해 방문한 30대 남성에서 경직장초음파로 측정한 전립선 용적을 후향적으로 분석하여 그 결과를 보고한 내용이다. 총 157명을 대상으로 하여 평균 연령은 $34.6{\pm}2.9$세이었고, 평균 전립선 용적은 $19.4{\pm}4.0ml$이었다. 전립선 용적은 연령, 전립선특이항원 수치, 체질량지수, 체표면적, 복부둘레와 양의 상관관계를 보였고, 특히 복부둘레와 가장 큰 상관관계를 보였다(r=0.317, p<0.001).

• 한국산림과학회지
• /
• 제105권3호
• /
• pp.330-335
• /
• 2016

본 연구는 중부지방소나무 등 주요 5개 수종에 대하여 상업적으로 이용가능한 재적율인 조재율을 구하기 위하여 수행되었다. 본 연구에 이용한 자료는 최소 1,300여본 이상의 전국적인 조사자료를 이용하였으며, 적용한 추정식은 임목재적 중 목질부 재적을 나타내는 목질부 재적율 추정식과 목질부 재적에 대한 이용재적을 나타내는 원목이용율 추정식이었으며, 이 두가지 추정식의 곱으로 조재율을 도출하였다. 흉고직경에 의한 목질부 재적율(W)은 $W=\frac{a_1}{1+a_2/D}+\frac{b_1}{1+b_2/D}$의 모형을 이용하였으며, 이 식의 적합도는 수종별로 99% 이상이었고 기타 검정통계량도 식의 적합성을 충분히 설명하고 있었다. 목질부 재적에 대한 원목이용율(M)은 $M=e^{a_1\(\frac{d}{D}\)^{a_2}}-(b_0+b_1D+b_2D^2+b_3D^3)$ 모형을 적용시켜 적합도는 수종별로 96% 이상이었다. 이 두가지 추정식을 이용하여 5개 수종별로 상업적 재적이용율인 조재율을 산정하고 조재율표를 작성하였다. 분석결과, 조재율은 침엽수와 활엽수 임상별로는 거의 차이가 없는 것으로 나타났으나, 기존 침엽수, 활엽수 조재율과의 차이는 있는 것으로 나타났다.

• 동아시아식생활학회지
• /
• 제21권6호
• /
• pp.863-870
• /
• 2011

In this study, muffins containing Bokbunja, popularly known as a psychological activator and functional material, was made, and its preference levels and qualitative characteristics were evaluated. We measured the height and weight of muffins containing Bokbunja powder. Height decreased when the volume of Bokbunja powder increased (p<0.001). When weight was measured, there was no meaningful difference between the samples, although the Bokbunja powder-containing samples were heavier than the samples not containing Bokbunja powder. When we measured the weight and specific volume of the muffins containing Bokbunja powder, the specific volume decreased when the amount of Bokbunja powder increased (p<0.001). The moisture and pH levels of the muffins not containing Bokbunja powder were 17.04% and pH 8.59, respectively. As the volume of Bokbunja powder increased, the moisture level of Bokbunja muffin increased while the pH decreased, and there was a significant difference (p<0.001). As a result of measuring the colors of muffins, the brightness of the muffins containing Bokbunja powder decreased, and the muffins showed decreased yellowness index and increased redness. In measuring the texture of Bokbunja muffins, hardness decreased as the volume of Bokbunja power increased (p<0.001). Further, springness of the muffins decreased as the volume of Bokbunja powder increased, and there was a significant difference (p<0.001). The chewiness of the muffins not containing Bokbunja powder was higher than any other muffin sample, and there was a significant difference between the samples (p<0.001). Further, the cohesiveness of the decreased as the volume of Bokbunja powder increased (p<0.001). Bokbunja muffins showed a lower gumminess index than those not containing Bokbunja powder (p< 0.05). When the sensual qualities of the muffins were measured, the color, flavor, taste, and softness of all of the samples showed significant differences (p<0.001), and the muffins containing 8% Bokbunja powder showed the highest sensual quality indexes. When the general preference level for the muffins was measured, the muffins containing 8% Bokbunja powder showed the highest index, 7.03${\pm}$0.96. Based on this result, the ideal volume of Bokbunja powder when making muffins is 8%.

• Journal of Periodontal and Implant Science
• /
• 제24권2호
• /
• pp.271-282
• /
• 1994

Active treatment of periodontal disease consists of plaque control by the patient, with root planing and surgery perfomed by the dental practitioner. Chlorhexidine rinse has been the most effective antiplaque agent available today and tetracycline has been the most favored antibiotics. Therefore, the purpose of this study was compared the different effect among groups(saline mouthrinse[group I], 0.125% chlorhexidine mouthrinse [groupII], and 0.125% chlorhexidine mouthrinse containing tetracycline[groupIII]) during the immediate post periodontal therapy. We assessed plaque index, gingival index, papillary bleediing index, gingival crevicular volume, periodontal attachment loss, and periodontal pocket depth in 3 sites per subject. The assessment was made at baseline. At 1 week after scaling, and at 2 weeks after curettage. All groups were clinically and statistically reduced plaque score, gingival score, papillary bleeding score, and gingival crevicular volume at 2 weeks after curettage. Group II was significantly reduced periodontal pocket depth.(P<0.05) At 1 week after scaling, al clinical index scores were reduced but not singificantly difference between the groups.(p>0.05) At 2 weeks after curettage, plaque score, gingival score and papillary bleeding score were significantly difference between the groups.(P<0.05) During the experimental period, gingiva was not damaged and stain of the tongue or teeth were not noted in all groups.

• Advances in nano research
• /
• 제9권4호
• /
• pp.251-261
• /
• 2020

In this article, vibration attributes of single walled carbon nanotubes based on Galerkin's method have been investigated. The influence of power law index subjected to different end supports has been overtly examined. Application of the Hamilton's variational principal leads to the formation of partial differential equations. The effects of different physical and material parameters on the fundamental frequencies are investigated for armchair and zigzag carbon nanotubes with clamped-clamped, simply supported and clamped-free boundary conditions. By using volume fraction for power law index, the fundamental natural frequency spectra for two forms of Single-Walled Carbon Nanotubes (SWCNTs) are calculated. The influence of frequencies against length-to-diameter ratios with varying power law index are investigated in detail for these tubes. MATLAB software package has been utilized for extracting tube frequency spectra. The obtained results are confirmed by comparing with available literature.

• Structural Engineering and Mechanics
• /
• 제60권5호
• /
• pp.875-890
• /
• 2016

A new structural damage index for seismic fragility analysis of reinforced concrete columns is developed based on a local tensile damage variable of the Lee and Fenves plastic-damage model. The proposed damage index is formulated from the nonlinear regression of experimental column test data. In contrast to the response-based damage index, the proposed damage index is well-defined in the form of a single monotonically-increasing function of the volume weighted average of local damage distribution, and provides the necessary computability and objectivity. It is shown that the present damage index can be appropriately zoned to be used in seismic fragility analysis. An application example in the computational seismic fragility evaluation of reinforced concrete columns validates the effectiveness of the proposed damage index.