• 응용통계연구
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• 제28권3호
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• pp.511-527
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• 2015

ARMA(p, q) 모형 분석에서 분산 안정화 또는 정규화를 위해 멱변환(power transformation)이 사용된다. 변환된 자료를 이용하여 분석이 이루어지며 원 자료의 예측을 위해 재변환이 사용된다. 이때 흔히 변환된 자료 분석에서 얻어진 예측값의 역함수 값이 원자료 예측값으로 사용되지만 이는 편향이 있는 것으로 알려져 있다. 이를 해결하기 위해 로그 변환의 경우 Granger과 Newbold (1976)는 로그-정규분포의 기댓값을 이용할 것을 제안하였다. 본 연구에서는 모의실험을 통하여 제곱근 변환과 로그 변환 후 재변환을 사용할 때 예측값으로 기댓값의 역함수를 이용하는 방법과 역함수의 기댓값을 사용하였을 때의 추정의 결과를 모의실험을 통하여 비교하였다.

• 응용통계연구
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• 제21권3호
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• pp.537-546
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• 2008

시계열자료 분석에 있어 주요 목적 중에 하나는 미래에 대한 예측 값을 추정하는 것이다. 이 논문에서는 정상자기회귀이동평균 모형에서 변환-역변환 방법을 이용하여 예측값을 구하는 과정에서 발생하는 문제에 대해 알아보고 회귀분석에서 제안되었던 smearing 추정방법을 시계열분석에서 사용할 수 있도록 붓스트랩을 이용하여 수정한 추정법을 소개한다. Yeo-Johnson 변환 (2000)을 이용한 KOSDAQ지수의 수익률 실증분석을 통해 기존에 사용되고 있는 방법의 문제점과 제안된 방법의 적절성에 대해 고찰해 보았다.

• 한국광물학회지
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• 제18권4호통권46호
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• pp.237-248
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• 2005

[ $Mg_{2}SiO_{4}{-}$ ]스피넬에서 올리빈으로의 역상변이에 대한 고온 X-선 회절실험 결과, 진공상태에서 가열하였을 때 상변이가 일어나며, 일정한 온도에서 스피넬상으로부터 올리빈상이 시간이 경과하면서 성장하는 것으로 보아 상변이 메커니즘은 '핵생성 및 성장' 형태인 것으로 판단된다. 스피넬 상으로부터 올리빈 상으로 역상변이 할 때의 활성화 에너지를 구하기 위해 $Mg_{2}SiO_{4}{-}$스피넬 시료에 대한 상변이 실험을 진공 및 고온($1023\∼1116\;k$)에서 시행하였다. 올리빈 상에 대해 '주어진 시간에 따른 비분율법'을 이용하여 활성화 에너지 값을 결정하였다. 아브라미 방정식을 이용하여 계산한 결과, n값은 대체로 온도가 증가함에 따라 매우 넓은 영역에서 동반 상승하는데, 이러한 현상은 '핵생성 및 성장' 메커니즘이 아마도 온도에 종속적이지 않느냐 하는 것을 제시해주고 있다. 상대적으로 낮은 온도에서는 $Mg_{2}SiO_{4}{-}$스피넬은 핵이 생성된 자리가 포화된 후, 새로운 결정상이 표면에서 성장을 시작하고 시간이 지남에 따라 내부 쪽으로 옮아가는 것으로 판단된다. 그러나 고온에서, 성장은 핵이 생성된 자리가 포화되고 난 후 표면뿐만 아니라, 내부에서도 동시에 시작되는 것으로 보인다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.964-968
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• 1996

The demands of size and quality of large steel shaft forgings for ship building, power plant, steel plant, etc. are rapidly increasing, and some of these productions are manufactured from ingot weighing more than 300 tons. For use as rotating components. shafts require toughness, strength and homogeneity, and therefore are produced through a variety of heat treatments. According to the increase of ingot size, micro- and macrosegregation and also mass effect of the product increase. Thus, special care should be paid to the heat treatment of such large shaft forgings. In this paper, the heat treatment of large shaft forgings such as rotor and back-up roll is calculated using the commercial finite element code SYSWELD. Calculated distributions of temperature and phase are compared with experimental data. The continuous cooling transformation diagram, thermal and mechanical properites of each phase are used. The phase proportion, hardness and residual stress during water quenching are discussed.

• Journal of Smart Tourism
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• 제1권1호
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• pp.69-74
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• 2021

Restaurants are an important area of the hospitality industry. This industry sector has not only experienced severe consequences of the recent lockdowns, but it has also seen the rise of digital technologies. As known from other industries, the digital transformation impacts products, processes and business models alike. Starting from the classical distinction of a restaurant's front- and back-of-the-house processes, this paper presents an overview on current developments in the restaurant industry and based on an analysis of current digital services, it derives some implications for future directions. Among the observations are that restaurants need to cover more touch points, provide more individualized offerings and strive for more automation as well as integration of their systems.

• 대한가정학회지
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• 제35권4호
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• pp.159-172
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• 1997

The purpose of this study was to investigate the slacks pattern making on the movement -fitness of the hip region. The experimental items were divided into the 5 lower limb movements(M1-M5) and the 12 revision pattern constructions of slacks. This study was done by clothing pressure test sensory evaluation test and the difference shape-transformation of wearing-slacks. The summarized finding resulted from experiments and investigation are suggested as follows: First by the clothing pressure tested by lower limb movements the clothing pressure score of the rabbit leap movement(M3) was the highest of all lower limb movements and the order of it in the another movement was the sit on knee(M4) the sit on chair(M2) the noble sitting(M5) from the highest to the lowest. And in comparision of clothing pressure tested by revision pattern to cover the extend of crotch-length 20。 inclined back-line construction method (CA4) showed the lowest. And in comparision of clothing pressure tested by revision pattern to cover the extend of crotch-length 20。 inclined back-line construction method (CA4) showed the lowest. And also for a role to cover hip circumference extendign CC4(1/5 hip.1cm longrightarrow linked back -line) method showed the lowest. Second by the sensory evaluation test based on the movement and revision patterns it was found that the functional factor score of the rabbit leap movement was the lowest in all movement however the score of revision patterns were higher than basic pattern. Third by the test to show difference in the shape-transformation of wearing-slacks on chair(M2) also need to be analyzed. The ration of the shape-transformation of the knee region showed the least value in the increased patterns of inclined angle of back-line(CA) and the differential methods of back-line inclined pattern making. But that of the hem-line did not show remarkable difference.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권6호
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• pp.380-386
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• 2000

This paper presents the mathematical modelling analysis of Brushless Synchronous Motor(BLSM). The dynamic and the steady state characteristics of BLSM are simulated and analyzed : electromagnetic torque, speed, line voltage, and current. We used mathematical modelling to model of BLSM with sinusoidal back EMF, namely the shaft transformation referencing rotor frame from a, b, c three to produce constant torque like synchronous motor. The experiment result has already similar to compare with simulation result : torque error about 7%, speed error about 5%. The validity of proposed modelling and analysis was confirmed by the experimental result.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.206.1-206.1
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• 2005

• Journal of Acupuncture Research
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• 제35권2호
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• pp.81-87
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• 2018

Background: The purpose of the present study was to evaluate efficacy and patient satisfaction of acupuncture or Chuna therapy for back pain. Methods: Amongst all the patients with back pain who had been treated at Sun-cheon korean medicine hospital, Dong-shin university, only patients that had received either acupuncture or Chuna manual therapy between September 1 and October 31, 2017 were selected and their medical charts retrospectively analyzed. A questionnaire was used in the investigation that consisted of a numeric rating scale (NRS), the Oswestry low-back pain disability index (ODI), general, emotional, conversational, and technical satisfaction. The questionnaire was completed before treatment and at weekly intervals (approximately). Treatment efficacy was analyzed using the first and last questionnaires. The last questionnaire was also used to establish patient satisfaction. The data were analyzed using SPSS for Windows version 21.0. Results: The NRS, Current degree of pain (ODI-1), and total ODI were significantly decreased in both the acupuncture and Chuna groups. The differences in NRS, ODI-1, and total ODI changes between treatment groups were not significant. There were no statistically significant differences between the acupuncture and Chuna groups in terms of general, emotional, conversational, and technical satisfaction. Conclusion: Acupuncture treatment significantly reduces NRS and ODI in patients who have back pain without structural transformation, and Chuna therapy significantly reduces NRS and ODI-1 in patients who have back pain with structural transformation. These results indicate that further studies should be conducted in more patients and over a longer period.

• Journal of Plant Biotechnology
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• 제31권4호
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• pp.261-266
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• 2004

Agrobacterium을 이용하여 도입된 유전자의 세대진전, 교잡 등에 따른 유전적 안정성을 확인코자, 형질 전환으로부터 얻어진 bar 유전자가 도입된 형질전환 식물체들을 상호 교배, 여교배, T$_4$ 세대까지의 자식의 반복 등에 의해 유전적 안정성을 검토하였다. 조합이나 계통에 따라서는 일부 멘델식 분리를 따르지 않고 제초제 Basta에 대한 저항성이 사라지거나 저항성개체보다 감수성개체가 기대치보다 많은 등의 경우가 있었으나, 대부분 멘델식 분리를 따르고 있어 세대진전, 교배 등에 의해서도 유전적 안정성이 높게 유지됨을 확인할 수 있었다.