• Investigative Magnetic Resonance Imaging
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• 제25권3호
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• pp.141-155
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• 2021

Purpose: To develop a 3D magnetic resonance fingerprinting (MRF) method for application in high resolution knee cartilage PD, T₁, T₂ mapping. Materials and Methods: A novel 3D acquisition trajectory with golden-angle rotating radial in k_xy direction and interleaved echo planar imaging (EPI) acquisition in the k_z direction was implemented in the MRF framework. A centric order was applied to the interleaved EPI acquisition to reduce Nyquist ghosting artifact due to field inhomogeneity. For the reconstruction, singular value decomposition (SVD) compression method was used to accelerate reconstruction time and conjugate gradient sensitivity-encoding (CG-SENSE) was performed to overcome low SNR of the high resolution data. Phantom experiments were performed to verify the proposed method. In vivo experiments were performed on 6 healthy volunteers and 2 early osteoarthritis (OA) patients. Results: In the phantom experiments, the T₁ and T₂ values of the proposed method were in good agreement with the spin-echo references. The results from the in vivo scans showed high quality proton density (PD), T₁, T₂ map with EPI echo train length (N_ETL = 4), acceleration factor in through plane (R_z = 5), and number of radial spokes (N_spk = 4). In patients, high T₂ values (50-60 ms) were seen in all transverse, sagittal, and coronal views and the damaged cartilage regions were in agreement with the hyper-intensity regions shown on conventional turbo spin-echo (TSE) images. Conclusion: The proposed 3D MRF method can acquire high resolution (0.5 mm³) quantitative maps in practical scan time (~ 7 min and 10 sec) with full coverage of the knee (FOV: 160 × 160 × 120 mm³).

• Tuberculosis and Respiratory Diseases
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• 제61권5호
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• pp.433-439
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• 2006

연구배경: COPD 환자에서 천식을 동반한 환자들이 많이 있다고 보고 되어 있었고 기관지 과민성이 높은 비율로 보고되어 메타콜린 기관지유발검사가 이두 질환을 감별에 어떤 의의가 있는지 알아보았고, 치료에 대한 도움을 얻고자 연구하였다. 방 법: 전북대학교병원에서 2004년 1월부터 2004년 12월까지 메타콜린 기관지유발검사를 시행한 환자를 대상으로 전향적으로 연구하였다. 65명의 천식환자 23명의 COPD환자, 대조군에서 메타콜린 기관지유발검사를 분석하였다. 결 과: 각 군의 $PC_{20}$의 평균값은 천식군, COPD군 및 대조군에서 각각 $8.1{\pm}1.16$, $16.9{\pm}2.21$ 과 $22.0{\pm}1.47mg/mL$이고, 천식군, COPD군 및 대조군의 메타콜린 기관지유발검사의 양성율은 각각 65%, 30%와 9%였다. 메타콜린 기관지유발검사 양성 판정 기준을 $PC_{20}$ 16 mg/mL 이하로 가정할 때 천식군과 COPD군의 양성율은 80%와 30%이었고 민감도, 특이도, 양성예측률 및 음성예측률은 각각 80%, 75%, 78%와 78%였다. 결 론: 메타콜린 기관지유발검사의 양성기준을 $PC_{20}{\leq}16mg/mL$으로 하였을 때 천식 및 COPD가 동반된 천식과 순수한 COPD의 감별에 보다 많은 도움을 줄 것으로 예상되며 궁극적으로 COPD 환자들에게 보다 개별적이고 적절한 치료적 접근에 도달할 수 있도록 해주는 진단 방법 중 하나가 될 수 있다고 생각한다.

• 한국전자통신학회논문지
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• 제15권1호
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• pp.161-166
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• 2020

본 논문은 통합 베이즈 티코노프 정규화 방법을 확장하는 것을 제시한다. 통합된 방법은 티코노프 정규화 모수와 베이즈 하이퍼 모수들의 관계를 정립하고 최대 사후 확률과 근거 프레임워크를 사용한 정규화 모수를 구하는 공식을 제시한다. 데이터 행렬의 차원이 m by n (m >= n)일 때, total misfit는 기존의 m에서 m ± n로 확장된다. 따라서 탐색 범위도 1에서 2n+1개의 정수로 확장된다. 선형 탐색보다는 황금분할 탐색으로 시간을 줄인다. 상대오차를 최적화하는 새로운 벤치마크를 제안하고 이를 목표로 하는 새 모델 선택 판정기준을 소개한다. 실험결과는 영상 복원 문제에 대하여 제안하는 방법의 효능을 보여준다.

• 정보교육학회논문지
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• 제10권1호
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• pp.37-46
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• 2006

구성주의 교수-학습모형인 문제중심학습법(Problem-Based Learning )은 초등학생의 HTML 학습에도 긍정적인 영향을 미칠 것으로 예상하였다. 본 연구에서는 문제중심학습(Problem-Based Leaning)과 전통적 강의-실습법을 HTML 학습에 적용하는 비교 실험을 통하여 학업 생취도의 차이와 그 효과성을 검중하였다 문제중심학습은 문제중심학습센터의 IMSA 모형에 근거하여 이루어졌다. 학업 성취도 평가는 이론 영역과 실기 평가 영역으로 나누어 수행하였다. 실험결과 학업 성취도의 이론 영역의 평가영역에서는 강의법과 문제중심학습법이 유의한 차이를 보이지 않았으며, 실기 평가 영역에서는 문제중심학습이 유의한 차로 우위의 학업 성취도를 나타냈다. 실험결과 프로그래밍 학습에서 구성주의 학습형태인 문제중심학습이 전통적 학습 방업에 비하여 긍정적인 효과가 있음을 검증하였다.

• 공학교육연구
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• 제19권1호
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• pp.31-36
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• 2016

These days, ICT-related products are pouring out due to development of mobile technology and increase of smart phones. Among the ICT-related products, wearable devices are being spotlighted with the advent of hyper-connected society. In this paper, a body-attached type wearable device using EMG(electromyography) sensors is studied. The research field of EMG sensors is divided into two parts. One is medical area and another is control device area. This study corresponds to the latter that is a method of transmitting user's manipulation intention to robots, games or computers through the measurement of EMG. We used commercial device MYO developed by Thalmic Labs in Canada and matched up EMG of arm muscles with gesture controller. In the experiment part, first of all, various arm motions for controlling devices are defined. Finally, we drew several distinguishing kinds of motions through analysis of the EMG signals and substituted a joystick with the motions.

• 천문학회보
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• 제40권1호
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• pp.49.2-49.2
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• 2015

IntraCluster Medium (ICM) located at the galaxy cluster is in the state of very hot, tenuous, magnetized, and highly ionized X-ray emitting plasmas. High temperature and low density make ICM very viscous and conductive. In addition to the high conductivity, fluctuating random plasma motions in ICM, occurring at all evolution stages, generate and amplify the magnetic fields in such viscous ionized gas. The amplified magnetic fields in reverse drive and constrain the plasma motions beyond the viscous scale through the magnetic tension. Moreover, without the influence of resistivity viscous damping effect gets balanced only with the magnetic tension in the extended viscous scale leading to peculiar ICM energy spectra. This overall collisionless magnetohydrodynamic (MHD) turbulence in ICM was simulated using a hyper diffusivity method. The results show the plasma motions and frozen magnetic fields have power law of $E_V^k{\sim}k^{-3}$, $E_M^k{\sim}k^{-1}$. To explain these abnormal power spectra we set up two simultaneous differential equations for the kinetic and magnetic energy using an Eddy Damped Quasi Normal Markovianized (EDQNM) approximation. The solutions and dimensions of leading terms in the coupled equations derive the power spectra and tell us how the spectra are formed. We also derived the same results with a more intuitive balance relation and stationary energy transport rate.

• 한국실내디자인학회논문집
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• 제27권2호
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• pp.86-97
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• 2018

In modern times, pluralistic social phenomena in which various values are pursed and recognized appear. The modern society called hyper-connected, intelligence information and zero marginal cost society in which shared value is commonly emphasized faces a paradigm shift to shared society system. In particular, sharing-based activities related with intelligence information sectors more prominently emerge in the high-tech informatization which has been accelerated. The purpose of this study is to understand design factors related with how attribution of the sharing culture is expressed in library spaces and examine how sharing infrastructure is established in users' spaces. As a research method, it initially conducted theoretical consideration of the sharing culture and information spaces, which can be regarded as sociocultural phenomena in modern times. Then, it drew sharing culture-based spatial design factors-access, openness and plurality. It analyzed configuration of spaces for sharing information-Cultural Commons (CC), Information Commons(IC) and Learning Commons (LC) - and infrastructure of information spaces, for library cases-five domestic and foreign public libraries-. The findings show that modern library spaces reflect historical needs for the sharing culture and actively serve their roles through spatial infrastructure including contents (programs) and services for sharing knowledge. The study is determined to be valuable as basic data in establishing the infrastructure of information spaces reflecting modern social trends and cultural phenomena, in expecting spatial structures in which knowledge is reproduced and planning spaces of libraries in the future.

• 문화기술의 융합
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• 제4권2호
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• pp.155-160
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• 2018

이 연구에서는 실버 미러 기판의 표면 강화 실험을 수행하여 Tollen의 방법과 ${\gamma}$-선 조사 방법으로 만든 은 표면의 특성을 확인했다. 인디고 카민의 표면 강화 효과는 은 거울 및 은 졸 표면에 의해 분석되었다. SERS 스펙트럼에 나타난 진동 모드는 HyperChem프로그램의 PM3 방법에서 문헌 및 반 경험적 계산에 근거하여 분석하였다. Indigo carmine의 흡착 배향은 표면 선택 규칙을 사용하여 분석해 본 결과 은 표면에 수직으로 약간 기운 형태로 흡착되었음을 알 수 있었다.

• 대한간호학회지
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• 제10권1호
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• pp.29-40
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• 1980

A Study on environmental factors influencing blood pressure control of a patient with essential pressure hyper -tension was conduct to the identification of differences of demographic characteristics, socioeconomic factors and living habits. This study was performed on 219 cases who were divided into two groups from Sept. 14 to Oct. 20, 1979. One is the group with complication in the departments of internal medicine and outpatient of 7 hospitals in Seoul. The other is the group without complication in the same places as above. The instrument applied to this study consists of 19 items amended through preliminary test after consideration of related literatural review and Nursing History made by Smith (1965）. The materials were analyzed by computer program. The findings were as follows : 1. The group with complication had more sleep disturbances than the group without complication 2. The group with complication used more short term coping method on stress than the group without complication. 3. The group with complication had a tendency to more intake of salt, fat, alcohols and cigretts than the group without complition, but there were no significant differences between two groups. 4. The group with complication were lower social class than the group without complication. 5. The group with complication were more single(Death of spouse, Divorce, Separation) in marital status than the group without complication.

• 대한기계학회논문집A
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• 제28권10호
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• pp.1574-1582
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• 2004

Binary manipulators have recently received much attention due to hyper-redundancy, light weight, good controllability and high reliability. The precise positioning of the manipulator end-effecter requires the use of many modules, which results in a high-dimensional workspace. When the workspace dimension is large, existing inverse kinematics methods such as the Ebert-Uphoff algorithm may require impractically large memory size in determining the binary positions of all actuators. To overcome this limitation, we propose a new inverse kinematics algorithm: the inverse kinematics problem is formulated as an optimization problem using real-valued design variables, The key procedure in this approach is to transform the integer-variable optimization problem to a real-variable optimization problem and to push the real-valued design variables as closely as possible to the permissible binary values. Since the actual optimization is performed in real-valued design variables, the design sensitivity becomes readily available, and the optimization method becomes extremely efficient. Because the proposed formulation is quite general, other design considerations such as operation power minimization can be easily considered.