• Bulletin of the Korean Chemical Society
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• 제3권2호
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• pp.37-44
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• 1982

In this work we have studied the multilayer stepwise adsorption of gases on solid adsorbents based on the previously developed theory. It is shown that stepwise adsorption isotherms emerge from our theory if an ad hoc adsorption regarding the degree of occupation for each successive layer is abolished and the effect of lateral intermolecular interactions among adsorbate molecules is included. In addition to these the effect of vertical interactions has also been taken into consideration. It seems that the vertical interaction plays a role in deciding the shape and the position of steps in resulting isotherms. It is evident from this research that it is the lateral interaction that is responsible for stepwise adsorption as long as the adsorbent surface is uniform and temperature is sufficiently low.

• 한국통신학회논문지
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• 제27권2B호
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• pp.125-136
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• 2002

셀간 비동기 방식의 WCDMA 시스템에서 셀간 동기를 맞추는 일은 매우 중요하며, 3 단계 셀탐색 과정에 의해 수행된다. 셀 탐색은 셀 탐색 시간을 줄이기 위해 각 단계가 파이프라인으로 동작하는 단계별 병렬 처리 방식으로 동작할 수 있다. 각 단계에서 실행 시간을 동일하게 설정할 경우 2단계는 최소한 1프레임의 처리시간을 소요하므로 1단계와 3단계에서 과도한 누적이 야기된다. 일반적으로 누적의 횟수가 증가할수록 사후적분 검파의 잇점은 감소한다. 따라서 단계별 병렬 처리로 인한 성능 개선은 그다지 크지 않다. 본 논문에서는 레일리 페이딩 채널에서 WCDMA 시스템에 대한 셀 탐색의 단계별 병렬 처리의 성능을 해석한다. 본 해석을 통해 각 단계에서 사후 검파 적분의 횟수와 채널간 전력 할당비 등 셀 탐색 파라미터에 대한 영향을 조사한다. 또한 각 단계의 처리 시간을 적절히 조절함으로써 단계별 병렬 처리 셀 탐색의 성능을 개선하고, 관례적인 단계별 직렬 처리 방식과 성능을 비교한다.

• KSBB Journal
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• 제14권6호
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• pp.639-642
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• 1999

키토산 올리고당을 보다 효율적으로 생산하고자 효소와 기질간의 특성을 조사한 다음, 이를 바탕으로 기질을 단계별로 첨가하여 생산 효율을 높일 수 있었다. 본 실험에 사용된 효소의 안정성을 조사한 결과 pH 5.0에서 6일 후에도 약 90% 이상의 효소활성을 유지하였다. 기질이 초기 농도에 따른 겉보기 수율은 0.5~2% 키토산 용액은 약 90% 이상이었으며, 그이상의 농도일 경우 감소하였다. 그래서, 수율을 증가시키기 위해 초기 반응 속도 및 겉보기 수율이 높은 기실 농도에 기질을 단계 별로 첨가한 결과, 분해 반응에 있어 겉보기 수율은 64.6%에서 83.2%로 증가하였고, 이에 따라 키토산 올리고당의 생산량은 10.52 mg/mL에서 12.26 mg/mL로 증가하였다. TLC분석 결과 Batch type과 기질을 단계별로 첨가하였을 경우의 올리고당 조성은 주로 3-5당이었다. 키토산 올리고당 생산을 위한 최적의 반응 조건은 pH 5.0, 40$^{\circ}C$에서 초기 반응 속도 및 수율이 높은 기질 농도인 2% 키토산 용액에 기질을 3시간마다 첨가할 때였다. 반응 시간에 따른 기질의 양과 효소를 보다 더 최적화하여 키토산 올리고당의 최종 농도와 겉보기 수율을 증가시킬 수 있었다.

• PNF and Movement
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• 제16권3호
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• pp.307-315
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• 2018

Purpose: The purpose of this study was to demonstrate the effects of a stepwise proprioceptive neuromuscular facilitation (PNF) pattern therapy in weightbearing positions on the balance and walking functions of a patient with subacute stroke. Methods: The patient was a 78-year-old man with right post-stroke hemiparesis who had decreased balance and gait function. During the baseline and withdrawal phases, no intervention was applied; however, in the intervention phase, the patient received a stepwise PNF pattern therapy in weight-bearing positions. Results: During the intervention phase, the LOS improved by 296.51% (from $2482.13mm^2$ to $626mm^2$), and walking speed improved by 18.70% (from 0.75 m/s to 0.64 m/s). The LOS and 10MWT values appeared to be clinically significantly improved after the intervention. In addition, the scores of the BBS and ABC scales improved by 100% (from 36 points to 18 points) and 56.52% (from 720 points to 460 points), respectively. Conclusion: These findings suggest that a stepwise PNF pattern therapy may be helpful in enhancing the balance and walking function of a patient with subacute stroke. Further studies are required to validate the results of this study.

• Asia-Pacific Journal of Atmospheric Sciences
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• 제54권4호
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• pp.611-622
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• 2018

Observed climate data are processed under the assumption that their time series are stationary, as in multi-step temperature and precipitation prediction, which usually leads to low prediction accuracy. If a climate system model is based on a single prediction model, the prediction results contain significant uncertainty. In order to overcome this drawback, this study uses a method that integrates ensemble prediction and a stepwise regression model based on a mean-valued generation function. In addition, it utilizes empirical mode decomposition (EMD), which is a new method of handling time series. First, a non-stationary time series is decomposed into a series of intrinsic mode functions (IMFs), which are stationary and multi-scale. Then, a different prediction model is constructed for each component of the IMF using numerical ensemble prediction combined with stepwise regression analysis. Finally, the results are fit to a linear regression model, and a short-term climate prediction system is established using the Visual Studio development platform. The model is validated using temperature data from February 1957 to 2005 from 88 weather stations in Guangxi, China. The results show that compared to single-model prediction methods, the EMD and ensemble prediction model is more effective for forecasting climate change and abrupt climate shifts when using historical data for multi-step prediction.

• 품질경영학회지
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• 제48권1호
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• pp.51-68
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• 2020

Purpose: The primary objective of this research is to develop the optimal operating conditions as well as their associated design spaces for a Cryogenic Submerged Arc Welding(SAW) process by improving its quality and productivity simultaneously. Methods: In order to investigate functional relationships among quality characteristics and their associated control factors of an SAW process, a stepwise design of experiment(DoE) method is proposed in this paper. Based on the DoE results, not only a multi-dimensional design space but also a safe operating space and normal acceptable range(NAR) by integrating statistical confidence intervals were demonstrated. In addition, the optimal operating conditions within the proposed NAR can be obtained by a robust optimal design method. Results: This study provides a customized stepwise DoE method (i.e., a sequential set of DoE such as a factorial design and a central composite design) for Cryogenic SAW process and its statistical analysis results. DoE results can then provide both the main and interaction effects of input control factors and the functional relationships between the input factors and their associated output responses. Maximizing both the product quality with high impact strength and the productivity with minimum processing times simultaneously in a case study, we proposed a design space which can provide both acceptable productivity and quality levels and NARs of input control factors. In order to confirm the optimal factor settings and the proposed NARs, validation experiments were performed. Conclusion: This research may provide significant contributions and applications to many SAW problems by preparing a standardization of the functional relationship between the input factors and their associated output response. Moreover, the proposed design space based on DoE and NAR methods can simultaneously consider a number of quality characteristics including tradeoff between productivity and quality levels.

• 대한간호학회지
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• 제31권4호
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• pp.561-570
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• 2001

Purpose: This study was conducted to detect the correlations and the main factors influencing depression, life satisfaction, burden, defenition of suffering, meaning of life, and suffering. Method: The samples were composed of 160 cancer patients who were or outpatients of four hospitals in Seoul. The reliability of the 6 instruments was tested with Cronbach's alpha which ranged from .62 to .90. The data was analyzed using a SAS program for descriptive statistics, Pearson correlation coefficients, and stepwise multiple regression. Results: The results were as follows: 1. The scores on the suffering scale ranged from 132 to 40 with a mean of 87.3 (SD 17.5). 2. There were significant correlations between all the predictive variables and even the amounts of suffering (r=.27-.84, p〈.05). 3. Stepwise multiple regression analysis showed that depression was the main predictor of suffering, and accounted for 71.6% of the variance. In addition burden accounted for 4.6% of the variance in suffering. The two variables combined to account for 76.2% of the variance in suffering. Conclusion: In conclusion and depression, burden were identified as important variables in explaining the suffering of patients with cancer.

• 한국멀티미디어학회논문지
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• 제25권5호
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• pp.670-675
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• 2022

This study proposes an improved binarization method to improve image recognition rate. The research goal is to minimize the information loss that occurs during the binarization process, and to transform the object of the original image that cannot be determined through the transformation process into an image that can be judged. The proposed method uses a stepwise segmentation method of an image and divides blocks using prime numbers. Also, within one block, a trapezoidal type of fuzzy is applied. The fuzzy trapezoid is binarized by dividing the brightness histogram area into three parts according to the degree of membership. As a result of the experiment, information loss was minimized in general images. In addition, it was found that the converted binarized image expressed the object better than the original image in the special image in which the brightness region was tilted to one side.

• 응용통계연구
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• 제10권1호
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• pp.137-149
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• 1997

본 논문에서는 푸리에 전개에 기초한 로그밀도추정법을 제안하였다. 삼각함수로 구성된 기저함수들은 베이즈정보 규준량에 근거하여 단계적 추가 및 삭제를 이용하여 결정하였고, 모수의 추정에는 최대가능성 방법을 이용하였다. 기존 자료의 분석 및 모의실험을 통하여 제안된 방법의 성능을 예시하였다.

• 약학회지
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• 제37권6호
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• pp.555-560
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• 1993

Methyl 3-[(phenylsulfonyl)methyl]-1, 4, 8-trimethoxy-2-naphthoate(7) preparad by 3 steps was condensed with 5-ethyl-2-cyclohexen-1-one(8) to afford the teracyclic aromatic ring system compound 10, which was stepwise converted into the precursor of 11-Deoxy-$\beta$-rhodomycinone by means of various functional groups transformation.