• 한국초등과학교육학회지:초등과학교육
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• 제41권4호
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• pp.627-641
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• 2022

본 연구는 많은 초등 교사들이 어려움을 호소한 '지구와 우주' 영역 중 '지구와 달의 운동' 단원에서 달 관측이 시작되는 첫 차시인 '하루동안 태양과 달의 위치는 어떻게 달라질까요?'에 대한 교사의 인식을 깊이 알아보며 후속 차시와 관련 활동 지도에 도움을 주고자 한 연구이다. 설문 문항은 교과서 설명, 탐구활동, 학습 목표 달성, 기타 의견 4가지로 범주화하여 제작하였고, 과학 심화 전공, 교직 경력, 본 단원 지도 경험을 구인으로 하여 설문 문항별 인식이 어떻게 다른지 분석하였다. 또한, 서술형 문항을 통해 설문에 참여한 교사들의 보다 다양한 견해를 파악할 수 있었다. 설문은 경기도 소재 초등학교에 재직하고 있는 67명의 교사가 참여하였다. 본 연구의 결론은 다음과 같다. 첫째, 하루동안 태양과 달의 위치 변화 교과서 서술에 대해 교사들은 긍정적인 인식과 부정적인 인식이 비슷하게 나타났다. 둘째, 하루 동안 태양과 달의 위치 변화 탐구활동 지도시 교사들 대부분이 대체 방법을 활용하는 것으로 나타났다. 그러한 경향은 대상이 태양·달일 경우 모두 상관이 없었고, 심화 전공, 교직 경력, 지도 경험에도 차이를 보이지 않았다. 셋째, 대부분의 교사들은 본 차시 학습을 통해 학습 목표를 달성할 수 있을 것이라고 응답하였다. 그런데 설문에 참여한 많은 교사들이 태양과 달의 위치 변화 지도에 다양한 어려움을 호소하였고, 대부분 대체 방법을 활용하는 것으로 나타났기에 이러한 결과는 교사들이 직접 관측을 하지 않아도 대체 방법을 통해 학습 목표를 달성할 수 있다고 여기는 인식을 보여준다.

• Imaging Science in Dentistry
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• 제54권1호
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• pp.71-80
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• 2024

Purpose: This study aimed to evaluate age-stratified radiographic features in temporomandibular joint osteoarthritis using cone-beam computed tomography. Materials and Methods: In total, 210 joints from 183 patients(144 females, 39 males, ranging from 12 to 88 years old with a mean age of 44.75±19.97 years) diagnosed with temporomandibular joint osteoarthritis were stratified by age. Mandibular condyle position and bony changes (flattening, erosion, osteophytes, subchondral sclerosis, and subchondral pseudocysts in both the condyle and articular eminence, thickening of the glenoid fossa, joint space narrowing, and joint loose bodies) were evaluated through cone-beam computed tomography. After adjusting for sex, the association between age groups and radiographic findings was analyzed using both a multiple regression model and a multinomial logistic regression model(α=0.05). Results: The prevalence of joint space narrowing and protruded condyle position in the glenoid fossa significantly increased with age (P<0.05). The risks of bony changes, including osteophytes and subchondral pseudocysts in the condyle; flattening, erosion, osteophyte, and subchondral sclerosis in the articular eminence; joint loose bodies; and thickening of the glenoid fossa, also significantly rose with increasing age (P<0.05). The number of radiographic findings increased with age; in particular, the increase was more pronounced in the temporal bone than in the mandibular condyle (P<0.05). Conclusion: Increasing age was associated with a higher frequency and greater diversity of bony changes in the temporal bone, as well as a protruded condyle position in the glenoid fossa, resulting in noticeable joint space narrowing in temporomandibular joint osteoarthritis.

• 한국연초학회지
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• 제27권1호
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• pp.127-133
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• 2005

This study was conducted to determine the aroma and volatile component changes from a different stalk positions of Korean flue-cured tobacco. Eight different stalk positions of flue-cured leaf tobaccos harvested in 2001 were used for this study. Thermal extraction method at two different treatment temperature($50\;amp;\;80^{\circ}C$) was applied for this experiment. Forty eight kinds of aroma and volatile components such as 2,4-heptadienal, hexadecane, 1-methyl-1H- pyridine, 2,5-dimethyl-1H-pyrrole were analyzed by using thermal extraction method. All of aroma and volatile components of leaf tobaccos were changed from a different stalk positions and treatment temperature. Leaf tobaccos in middle stalk position have a higher concentration of aroma and volatile components such as norsolanidione, 4-pyridinecarboxaldehyde, 4-methyl-4-OH-2-pentanone, acetic acid, propylene glycol, 1-methyl-2-pyrrolidinone, 2,5-dimethyl-1H-pyrrole. Also, Megastigmatrienone 1, 3-oxo-[alpha]­ionol, 6,10,14-trimethyl-2-pentadecanone, heptadecane, 6-methyl-2-isohexyl-l-heptene concentration were low in the middle stalk position and high in both bottom and upper position. Treatment temperature affected on the changes of many aroma and volatile components in leaf tobacco. Most of aroma and volatile components such as, 2,4-Heptadienal, dodecanoic methylester, famesol isomer and 3-acetylpyridine were sharply increased as increasing treatment temperature. This results can be used to estimate the aroma characteristics of cigarette blend using a different stalk position of leaf tobacco.

• 한국소음진동공학회논문집
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• 제15권8호
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• pp.954-961
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• 2005

This paper is concerned with the implementation of auto-tuning positive position feedback controller using a digital signal processor and microcontroller. The main advantage of the positive position feedback controller is that it can control a natural mode of interest by tuning the filter frequency of the positive position feedback controller to the natural frequency of the target mode. However, the positive position feedback controller loses its advantage when mistuned. In this paper, the fast fourier transform algorithm is implemented on the microcontroller whereas the positive position feedback controller is implemented on the digital signal processor. After calculating the frequency which affects the vibrations of structure most, the result is transferred to the digital signal processor. The digital signal processor updates the information on the frequency to be controlled so that it can cope with both internal and external changes. The proposed scheme was installed and tested using a beam equipped with piezoceramic sensor and actuator. The experimental results show that the auto-tuning positive position feedback controller proposed in this paper can suppress vibrations even when the target structure undergoes structural change thus validating the approach.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.498-503
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• 2005

This paper is concerned with the implementation of adaptive positive position feedback controller using a digital signal processor and microcontroller The main advantage of the positive position feedback controller is that it can control a natural mode of interest by tuning the filter frequency of the positive position feedback controller to the natural frequency of the target mode. However, the positive position feedback controller loses its advantage when mistuned. In this paper, the fast fourier transform algorithm is implemented on the microcontroller whereas the positive position feedback controller is implemented on the digital signal processor. After calculating the frequency which affects the vibrations of structure most the result is transferred to the digital signal processor. The digital signal processor updates the information on the frequency to be controlled so that it can cope with both internal and external changes. The proposed scheme was installed and tested using a beam equipped with piezoceramic sensor and actuator. The experimental results show that the adaptive positive position feedback controller proposed in this paper can suppress vibrations even when the target structure undergoes structural change thus validating the approach.

• 경영과학
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• 제34권2호
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• pp.103-113
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• 2017

The artillery is a key element of the ground forces operation during wartime, and the military engineers support the artillery position development operation to support the smooth operation of the artillery. In establishing the artillery position development operation plan, the commander requires more than his intuition to find the best option reflecting a number of elements of the battlefield situation which changes every minute. Moreover, the number of available equipment is smaller than the number of required position developments, and the effective equipment operation becomes essential element of this issue. This study quantified the capability of the available engineering equipment, organized a number of teams enabling equipment to put out the maximum capacity based on the quantified figures, and formed the model which allocates the team to the developing points to minimize the developing time. The goal programming method was applied to resolve the problem. The developed model was applied to compare the total mission duration following the number of teams, the variable for commander's decision, and the result of this study can be used as the quantitative data for commander's decision making process in establishing the artillery position development support operation through effective equipment management.

• 한국멀티미디어학회논문지
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• 제16권8호
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• pp.934-942
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• 2013

영상 크기 변환은 응용 환경에서의 다양한 목적을 위하여 사용되며, 변환 함수의 성능을 평가하기 위하여 처리전과 후의 두 영상의 화질을 비교한다. 변환 함수의 객관적 성능 평가를 위하여 화질 비교의 정확한 지표가 요구되며, 실제 다양한 관점에서의 접근이 이루어졌다. 하지만 영상 크기 변환 과정에서 생략되거나 새롭게 생성되는 화소들의 위치를 고려한 화질 비교 척도에 관한 연구는 거의 이루어지지 않고 있다. 따라서 본 논문에서는 영상 크기 변환에서 발생하는 화소들의 생략 및 추정 위치를 고려한 객관적 영상 화질 측정방법을 제안한다. 제안하는 방법은 기존의 영상 화질 척도를 이용하여 위치 변화를 고려한 새로운 영상화질 측정 방법을 만들고, 위치 변화에 대한 민감도를 평가하였다. 실험을 통해서 기존에 널리 사용되는 영상 화질 측정 방법이 화소들의 생략 및 추정 위치의 변화에 많은 영향을 받는 것을 알 수 있었고, 제안하는 방법이 화소들의 생략 및 추정 위치 변화를 고려한 영상 화질 표현의 객관적 척도임을 확인하였다. 제안하는 방법은 영상 복원 및 개선 함수의 성능을 평가하는 척도로서 유용하게 사용될 수 있다.

• 대한기계학회논문집B
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• 제33권4호
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• pp.215-224
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• 2009

Analysis for various driven nozzle position changes. The analysis was done for different Reynolds number in entrance region of jet-pump and for several diameter ratios of driven nozzle. (1) The largest absorption energy was found at the point s=1 in condition of diameter ratio 1:3.21 and point s=0.5 in condition of diameter ratio 1:2.25. (2) The absorption energy was not related to the change of entrance velocity and the driven nozzle position having the largest absorption energy was function for cross section ratio. (3) As the position of driven nozzle moves to the downstream, the absorption energy gets weaker. Because the energy from swirl was lost at the cross section gets smaller. (4) As the position of driven nozzle moves to the downstream, the injection energy leans to the upper direction wall and as the Reynolds number increase, the lean phenomenon is more distinct. (5) The flow quantity of driven nozzle, the diameter ratio 1:3.21, was 32% higher than that of 1 : 2.25 and as the inlet velocity gets faster the efficiency decreased. And as the cross section of the driven nozzle increases.

• Journal of Oral Medicine and Pain
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• 제21권1호
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• pp.55-65
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• 1996

This study was performed to investigate the effects of head posture and occlusal splint on the vertical dimension in mandibular rest position and swallowing. Thirty health dental students ware selected lot this study and BioEGNⓡ(Bioresearch Inc., USA) was used for measuring interocclusal distance during rest - swallowing - rest - tapping movement. This swallowing movements were observed in both normal head posture(NHP) and forward head posture (FHP). Thickness of occlusal splint was about 2mm at posterior molar area and even tooth contact were achieved on light biting. The four mandibular positions at which interocclusal distance measured were swallowing position, after swallowing position in which interocclusal distance was maximum, rest position follows swallowing, and tapping position after rest. Changes of distance in each position were measured for three mandibular planes, that is, sagittal, frontal, and horizontal plane, respectively. The results obtained were as follows : 1. In normal head posture, the mandible was raised 1.03mm without splint, and 0.77mm with splint on swallowing, and there was no significant difference between the two. In horizontal plane, however, mandible was displaced more anteriorly in both swallowing position and tapping position with splint. 2. In forward head posture, the mandible was less raised with splint on swallowing, but features in horizontal plane were almost same as those in normal head posture. 3. In natural dentition, significant difference between NHP and FHP were observed in horizontal plane trajectory for swallowing and tapping position. But the difference for same positions were observed in frontal trajectory with splint. 4. Total amount of mandibular movement of two groups classified with sagittal interocclusal distance of swallowing position generally showed significant difference between the higher and the lower height group in head posture without splint. 5. Correlationship among total amount of mandibular movement for three mandibular planes were observed between sagittal plane and horizontal plane, and between sagittal plane and frontal plane in head posture without splint.

• The Journal of Korean Physical Therapy
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• 제28권6호
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• pp.381-384
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• 2016

Purpose: Previous studies reported changes in the first metatarsophalangeal (MTP) joint angle in relation with and without weight bearing, but it is unclear whether sesamoid bone of the great toe changes in weight bearing conditions particularly in subjects with hallux valgus (HV). To investigate how weight bearing conditions can affect the position of the medial sesamoid bone (MSB), first MTP joint angle, and second intermetatarsal angle (IMA) in the recruited subjects. Methods: Subjects were recruited 24 with HV and 21 without HV in study. X-rays were taken in the weight bearing and non-weight bearing conditions. The distance of the MSB, first MTP joint angle, and second IMA were measured from the radiographs. Data were analyzed by paired and Independent t-test. The statistical significance level was p<0.05. Results: In both groups, the first MTP joint angles and the distance of the MSB were significantly smaller, while the second IMA was significantly greater in the weight bearing condition. The difference in the distance of the MSB between the two postures was significantly greater in the group with HV. Conclusion: Weight bearing can affect the first MTP joint angle, second IMA, and position of the MSB; the change in the position of the MSB in weight bearing was greater in the group with hallux valgus. The difference in these variables between weight bearing and non-weight bearing conditions may be considered when measuring HV.