• 한국수학교육학회지시리즈C:초등수학교육
• /
• 제23권2호
• /
• pp.87-116
• /
• 2020

본 연구의 목적은 학생의 단위 조정 능력이 분수 개념 이해와 어떻게 관련되는지 탐구하는 데 있다. 이를 위해 초등학교 4학년 학생을 대상으로 4개월(2019.3.~2019.6.)에 걸쳐 교수 실험을 진행하였고 본 논문에서는 학생의 분수 개념 이해와 관련된 스킴과 조작이 교수 실험 동안 어떻게 변화하였는지에 대한 상세한 분석을 제시하였다. 학생의 단위 조정 조작은 분수 개념을 이해하는 능력과 밀접한 연관이 있는 것으로 나타났는데, 수업 초반에 부분 분수 스킴의 학생은 분수를 2수준 단위를 가지고 조작함으로써 분수를 또 다른 종류의 자연수로 인식하였다. 학생은 진분수와 전체 1을 단위 분수의 배수로 동시에 인식하면서 분수를 자연수와 명확히 구분하였다. 역 부분 분수 스킴의 학생은 1보다 큰 자연수를 내재화된 3수준 단위로, 자연수 아닌 가분수를 활동 중에 3수준 단위로 구성하였다. 본 연구의 결과를 바탕으로 결론 및 교수학적 시사점을 제시하였다.

• Transactions on Electrical and Electronic Materials
• /
• 제18권4호
• /
• pp.229-236
• /
• 2017

This paper deals with the design and implementation of an efficient topology for cascaded multilevel inverters with reduced part counts. In the proposed design, a well-established basic unit is first developed. The series extension of this unit results in the formation of the proposed multilevel inverter. The proposed design minimizes the number of power electronic components including insulated-gate bipolar transistors and gate driver circuits, which in turn cuts down the size of the inverter assembly and reduces the operating power losses. An explicit control strategy with enhanced device efficiency is also acquired. Thus, the part count reductions enhance not only the economical merits but also the technical features of the entire system. In order to accomplish the desired operational aspects, three algorithms are considered to determine the magnitudes of the dc voltage sources effectively. The proposed topology is compared with the conventional cascaded H-bridge multilevel inverter topology, to reflect the merits of the presented structure. In continue, both the analytical and experimental results of a cascaded 31-level structure are analyzed. The obtained results are discussed in depth, and the exemplary performance of the proposed structure is corroborated.

• 보건행정학회지
• /
• 제12권4호
• /
• pp.34-55
• /
• 2002

In this study, the impact of organizational culture on the quality of social work services in hospitals were empirically analysed. A mailed questionnaire survey was conducted between February 19 and April 10, 2001. A sample of total 70 hospitals, including general hospitals with one social worker at least and single-department hospital with two social workers or more, were identified nationwide through the registry of Korean Association of Medical Social Workers and Korean Association of Hospitals. According to coping strategy and reacting pattern with the environmental changes, four types of organizational culture in each hospital, classified as group culture, developmental culture, hierarchial culture, and rational culture, were adopted for the independent variables. Three dimensional aspects of quality of social work service - structure, process, and outcome were selected as dependent variables in this study. Also the quality of social work service was distributed into provider-perceiving quality and consumer-perceiving quality The major findings were as following in summary; First, most social workers reported that the characteristic of culture in their hospitals are group culture the first, hierarchial culture the second, developmental culture the third, and rational culture finally in order of comparing the level of quality perceived between social worker's recognition. Second, service provider and consumer, The provider-perceiving quality showed less score than that of consumer, especially the lowest was the score of quality of outcome perceived by provider. Third, according to the types of organizational culture, there were significantly different levels of quality in total social work services, structure dimension and process dimension. The quality of outcome dimension did not show significant differences among the type of organizational culture. Finally, the most influential variables to the quality of social work service ice proved departmental form of social work unit, leader of social work unit, and developmental culture of hospital To assure quality services, accordingly, social work unit in hospital is required to be organized as a single unit, that means to be an independent department of which qualified social worker is supposed to control the unit. It is strongly recommended to develop leadership for the leaders of social work unit.

• 한국건축시공학회지
• /
• 제16권1호
• /
• pp.87-96
• /
• 2016

More than half of Korea's urban population currently lives in multi-unit dwellings. This particular residence structure inevitably positions the living spaces of residents in close proximity to one another. Because of this proximity, the sounds of a particular household will transfer to other residents' units creating conflict between tenants. Efforts to alleviate this problem have been made in both the public and private sector. A prominent method of noise analysis between living units has been to make an actual sound measurement and obtain qualitative measurements from questionnaires. Although this method has been most widely used, such analysis requires a large amount of human effort and time. In addition, the questionnaire method fails to provide the objective information needed to accurately assess the noise situation. To overcome the inadequacies of this previous method, this study seeks to evaluate the applicability of an acoustic simulation method. Three types of living noises were analyzed to assess the noise levels passed between multi-unit dwellings. The acoustic simulation method was found to be more economical, efficient, and adaptable in information processing. The results of this study can be further applied to design and control living-noise through procedures such as acoustic absorption or space redesign.

• 한국수학교육학회지시리즈A:수학교육
• /
• 제61권1호
• /
• pp.1-28
• /
• 2022

본 연구의 목적은 비례 문제 해결 과정에서 학생의 분수 지식이 어떻게 관련되어 나타나는지를 탐구하는 것이다. 이를 위해 단위 조정 3단계로 판단되는 중학교 1학년 학생 2명에 주목하여 분수 지식과 비례 문제 해결 과정에 대한 임상 면담 자료를 분석하였다. 분석 결과 자연수 맥락에서 단위 조정 3단계 학생으로 판단되었던 두 학생은 분수 맥락에서는 '활동을 통해' 3수준 단위를 조정하며 서로 다른 양적 조작 방식을 보여주었다. 특히 두 학생이 가분수가 포함된 곱셈 연산 과제에서 보여주었던 분할 조작과 단위 조정 활동에서 식별되었던 차이는 두 학생의 비례 문제에 대한 접근 방식에 있어서 중요한 차이로 나타났다. 이 과정에서 하나의 3수준 단위로부터 또 다른 3수준 단위 사이의 구조적 전환이 '재귀 분할의 내재화'와 관련이 되며, 합성 단위에 대한 스플리팅 조작에 중요한 근거가 됨을 시사하였다.

• 비파괴검사학회지
• /
• 제32권6호
• /
• pp.678-685
• /
• 2012

The objective of this study is to monitor the health status of harbor caissons which have potential foundation damage. To obtain the objective, the following approaches are performed. Firstly, a structural damage monitoring(SDM) method is designed for interlocked multiple-caisson structures. The SDM method utilizes the change in modal strain energy to monitor the foundation damage in a target caisson unit. Secondly, a finite element model of a caisson system which consists of three caisson units is established to verify the feasibility of the proposed method. In the finite element simulation, the caisson units are constrained each other by shear-key connections. The health status of the caisson system against various levels of foundation damage is monitored by measuring relative modal displacements between the adjacent caissons.

• 대한임상전기생리학회지
• /
• 제8권1호
• /
• pp.23-29
• /
• 2010

Purpose : This study is to offer clinical primary data that examines the change of imaging structure and the quantitative evaluation of muscle activity on myofascial trigger points. This study examines neuromuscular physiological characteristic by comparing the differences in physical findings, pressure pain threshold, imaging, and electrophysiological characteristics in latent and active myofascial trigger points muscle and normal muscle through the following experimental procedures. Methods : The participants for the study were thirty-three adults in their twenties. We divided three groups into normal, latent and active myofascial trigger points groups by physical findings. We analyzed the results of measured pressure pain, threshold for pain, ultrasound imaging perform for structure characteristic of muscle, surface EMG according to type of muscle contraction for function of muscle contraction. Results : Significant differences were indicated in pressure pain threshold (p<0.05). Significant differences were discovered in the ultrasound imaging analysis. There were increases in muscle Echogenicity white area index (p<0.001). There were significant differences that decrease in %MVIC (p<0.05), increase in MDF (p<0.05). Conclusion : From these results, active rnyotascial trigger points muscle showed quality deterioration on ultrasound imaging and decreased function of muscle contraction, increased motor unit action potential of II type fiber, and electrophysiologically. Imaging structure and neuromuscular physiological characteristic can be diagnostic and quantitative analytical techniques for myofascial pain syndrome and a primary factor that reflected in physical therapy intervention.

• 대한수학교육학회지:학교수학
• /
• 제14권1호
• /
• pp.45-64
• /
• 2012

본 정성 연구에서는 교사들의 등분제 분수 나눗셈에 대한 지식을 분석하였다. 자료 수집은 13명의 교사들이 참여한 분수, 소수, 비례 등에 대한 주제를 다룬 40시간의 교사교육 프로그램으로부터 수집되어 일부분이 활용되었으며, 교사들의 등분제 분수 나눗셈 지식을 세밀하게 분석하기 위해 두 가지 지식 요소들 (단위에 대한 지식, 분할 조작)을 분석틀로 사용하였다. 그 결과, 제수와 피제수가 서로소인 등분제 나눗셈 문제 상황을 다루는 능력이 두 지식 요소의 사용여부와 수준에 따라 다르게 나타났다. 두 단계의 단위 구조만을 가지고 추론한 교사의 경우 한 사람의 몫을 주어진 단위로 정확하게 나타낼 수 없었다는 점에서 제한점을 보였으며, 세 단계의 단위 구조를 가지고 추론한 교사는 다양한 분할 조작과 참조 단위의 활용으로 보다 유연하게 문제 상황에 대처할 수 있음을 보여주었다.

• 대한수학교육학회지:학교수학
• /
• 제18권3호
• /
• pp.625-645
• /
• 2016

본 연구는 이분모분수의 덧셈 및 뺄셈과 관련하여 단위 추론의 측면에서 강조해야 할 핵심 아이디어를 밝히고 제4차 교육과정에서부터 2009 개정 교육과정에 의한 초등학교 교과서에서 단위와 관련된 아이디어가 어떻게 제시되어 있는지를 분석하였다. 연구 결과 이분모분수의 덧셈과 뺄셈의 핵심 아이디어는 세 가지 수준의 단위를 유연하게 활용하는 과정에서 고정된 전체 단위, 새로운 공통 단위의 필요성, 재귀적 분할 등을 강조해야 한다는 것이다. 초등학교 수학 교과서 분석 결과, 전체 단위가 고정되어야 한다는 사실을 매우 암묵적으로 다루고, 통분의 필요성을 이전에 학습한 동분모분수의 덧셈과정과 연결하여 제시하였으며, 재귀적 분할 방법보다는 수치적으로 통분하여 모델을 알고리즘과 유기적으로 연결하는 데 어려움이 있는 것으로 드러났다. 이에 대한 논의를 바탕으로 초등학교 수학교과서의 이분모분수의 덧셈과 뺄셈 관련 내용 구성 및 지도 방향에 시사점을 제공하고자 한다.

• Journal of Periodontal and Implant Science
• /
• 제27권1호
• /
• pp.263-290
• /
• 1997

Homogenization technique is employed to investigate the series of stress analyses of mandible for three different types of dental implants. This technique helps to make proper material model of bone and analyze such a non homogeneous structure at the level of individual microstructural unit. The stress analyses with homogenization technique show much higher stress level in the sponge bone, compared to those of conventional FEM. It also manifested that even a minor lateral force results in crucial stresses in the dental implant system and that the macroscale model should take the shape and size after real mandible to produce reasonable solution in the analyses of dental implant systems. The shapes of dental implants simulated in this study are rectangular-cross-sectioned type, hemi-sphere rooted type, and wedge type implant. The stress states of mandible with hemisphere rooted type implant and wedge type implant show similar levels, while those with sectioned rectangular implant results in higher stresses. It is suggested that the distance between the implant tip and cortical bone be kept far enough to prevent stress concentrations in the mandible.