• 암석학회지
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• 제10권3호
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• pp.133-147
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• 2001

최근 기존 연대측정법의 한계를 극복하여 절대연령 측정 대상을 획기적으로 넓힐 수 있는 방법으로 개발되고 있는 단계적 용해에 의한 연대측정법을 국내 시료에 적용하여 이 방법에 의한 연대측정의 성공가능성에 대해 평가하여 보았다. 대상 시료는 옥천변성대 대전 남부지역 창리층의 함우라늄 흑색 점판암, 영남육괴 북동부의 선캠브리아 내덕리 화강암에서 분리한 전기석 및 옥방광산의 회중석 등을 선정하였다. 이들에 대한 단계적 용해를 위해 산의 종류와 시간을 달리하여 점차 그 세기를 늘려가며 납을 용출시켰으며, 각 단계에서 얻은 용액들에 대해 납 등위원소 비율과 함께 납과 우라늄 함량을 열이온화 질량분석기로 측정하였 다. 그 결과 창리층 혹색 점판암과 내덕리 화강암으로부터는 상당한 Pb 동위원소 값의 분산을 얻을 수 있었으며 단계적 용해에 의한 Pb-Pb 연대측정이 성공적일 수 있음을 보여준다. 단계적 용해 과정에서 시료의 종류마다 우라늄과 납의 거동이 다르며 이는 구성 광물의 종류에 따라 우라늄과 납이 차지하는 결정 내에서의 위치에 지배되는 것으로 판단된다.

• 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.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.73-76
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• 2000

We investigate the stepwise parallel processing of the serial search which can success the co]1 search at low Ec/Io. The single path Rayleigh fading channel which is worst-case channel model is considered. The typical 3-step cell search is used. The probabilities of detection, miss and false alarm for each step are used in closed forms based on the statistics of CDMA noncoherent demodulator output. The optimal power allocation to each channel and The optimal number of post-detection integrations for each step is obtained. Also, the cumulative probability distribution of the average eel] search time for serial search methods are compared.

• Journal of the Korean Data and Information Science Society
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• 제19권3호
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• pp.789-800
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• 2008

Current credit evaluation models based on financial data make use of smoothing estimated default ratios which are transformed from each financial variable. In this work, some problems of the credit evaluation models developed by financial experts are discussed and we propose improved credit evaluation models based on the stepwise variable selection method and Box-Cox transformed data whose distribution is much skewed to the right. After comparing goodness-of-fit tests of these models, the validation of the credit evaluation models using statistical methods such as the stepwise variable selection method and Box-Cox transformation function is explained.

• 한국멀티미디어학회논문지
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• 제6권4호
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• pp.630-637
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• 2003

This study is designed to use the stepwise learning system for solving learner-oriented problem on the Web, which can help learners probe studying targets and contents of mathematics as well as search for a study-related materials. The study provides a Web-based Courseware design model based on the general multimedia systematic professor design model. It develops a program for remote lecture that can solve problems through interaction among a professor and the other learners. It also implements a remote teaming system for real-time environment of mathematical problems oriented by the learner. The system designed either as a Web-based mathematical Courseware or as a text mode has the purpose of providing a Web-based stepwise learning system for solving mathematical problems oriented by the learner.

• 한국양식학회지
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• 제17권1호
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• pp.8-11
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• 2004

Milt of the catfish was stripped into immobilizing solution containing 175 mM NaCl and 30 mM Tris at pH 7.8 and was successfully cryopreserved after a stepwise freezing procedure. After stepwise thawing, motility of spermatozoa was slightly lower than that of fresh sperm. Batches of 40-80 eggs were fertilized with cryopreserved spermatozoa, after thawing and activation in solution containing 50 mM NaCl, 20 mM Tris and HCl at pH 7.8; this resulted in 62.2% fertilization success, compared to 70.6 % with fresh sperm.

• JSTS:Journal of Semiconductor Technology and Science
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• 제1권3호
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• pp.167-181
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• 2001

A stepwise driving method was used for reducing the AC power consumption in a TFT-LCD. The AC power takes the largest portion of the total power consumption of a TFT-LCD. Experimental results confirmed that the AC power saving efficiency reached up to 75% when a 5-stepwise driving with each step time of $2\mu$ sec was applied to a 14.1 inch-diagonal XGA TFT-LCD. The second largest component of power consumption called the DC power comes from the quiescent currents in Op-amps. A simple and efficient architecture was proposed in this work to reduce this DC power consumption: Half of the Op-amps have the 5V-supplies, and the rest half have the 10V-supplies, and two Op-amps are shared by adjacent two channels. Measurements of test circuits showed that this simple method could reduce over 40% of the DC power consumption..

• Journal of the Korean Wood Science and Technology
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• 제27권4호
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• pp.51-56
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• 1999

Finite element method was utilized to analyze crack tip stress and displacement field under drying stress case as stepwise loading. Opening mode of single-edge-notched model was employed and analyzed by linear elastic fracture mechanics of plane stress case. The drying stresses were applied as stepwise loads at the boundary elements of the model with 10 steps of time serial. The stress intensity factor($K_I$) for opening mode reached to its maximum just prior to the stress reversal. The $K_I$ from the displacement fields revealed 1.7 times higher than those from stress fields. By comparing the two sets of $K_I$ from displacement and stress fields, single parameter $K_I$ showed its validity to characterize displacement fields around the crack tip front while stress field could not be characterized due to large variations between two sets of data.

• Steel and Composite Structures
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• 제23권1호
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• pp.107-114
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• 2017

Design of stepwise foam claddings subjected to air-blast is performed based on random Voronoialgorithm. FE models are constructed using the random Voronoialgorithm, and numerical analysis is carried out to simulate deformation mode and energy absorption of the cladding by the ABAQUS/Explicit software. The FE model is validated by test result, and good agreement is achieved. The deformation patterns are presented to give an insight into the influences of distribution on deformation mechanisms. The energy absorbed by the stepwise foam cladding is examined, and the parameter effects, including layer number, gradient, and blast loading, are discussed. Results indicate that the energy absorption capacity increases with the number of layer, gradient degree, and blast pressure increasing.

• 한국재료학회지
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• 제27권9호
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• pp.484-488
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• 2017

In the present study, domain evolution processes of a near-morphotropic PZT ceramic during poling was studied using vertical piezoresponse force microscopy (PFM). To perform macroscopic poling in bulk polycrystalline PZT, poling was carried out in a stepwise fashion, and PFM scan was performed after unloading the electric field. To identify the crystallographic orientation and planes for the observed non-$180^{\circ}$ domain walls in the PFM images, compatibility theory and electron backscatter diffraction (EBSD) were used in conjunction with PFM. Accurate registration between PFM and the EBSD image quality map was carried out by mapping several grains on the sample surface. A herringbone-like domain pattern consisting of two sets of lamellae was observed; this structure evolved into a single set of lamellae during the stepwise poling process. The mechanism underlying the observed domain evolution process was interpreted as showing that the growth of lamellae is determined by the potential energy associated with polarization and an externally applied electric field.