• Journal of Korean Neurosurgical Society
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• 제45권2호
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• pp.122-126
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• 2009

Single-balloon kyphoplasty via an extrapedicular approach has been reported to be effective because it requires less time than conventional two-balloon kyphoplasty and has comparable therapeutic efficacy. However, single-balloon kyphoplasty is not popular because the extrapedicular approach is believed to be complicated and unsuitable for the thoracolumbar and lumbar spine. The authors describe a standardized surgical technique that utilizes a far-lateral extrapedicular approach for single-balloon kyphoplasty, which can be performed in any part of the spine by physicians without substantial difficulty.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제15권2호
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• pp.115-126
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• 2011

The aim of this study was to explore teachers' values about teaching mathematics in the classrooms which implemented Lesson Study and Open Approach as a teaching approach. The targeted group was 83 school teachers from 4 schools participating in a teacher professional development project. The data was gathered through teacher questionnaires, lesson observations and interviews. Data analysis is based on Bishop's (1988; 2003; 2007) and Komin's (1990) frameworks. The results from the implementation of Lesson Study and Open Approach in Thai classroom found the different of the roles and behaviors of teachers and students in classroom. The results revealed 3 kinds of values about teaching: Mathematical values, General educational values, Mathematics educational values and also found that most of the teachers valued problem solving as an innovative teaching approach as against traditional approaches they were familiar with.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제10권3호
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• pp.151-167
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• 2006

The open approach to teaching school mathematics in the United States is an outcome of the collaboration of Japanese and U. S. researchers. We examine the approach by illustrating its three aspects: 1) Open process (there is more than one way to arrive at the solution to a problem; 2) Open-ended problems (a problem can have several of many correct answers), and 3) What the Japanese call 'from problem to problem' or problem formulation (students draw on their own thinking to formulate new problems). Using our understanding of the Japanese open approach to teaching mathematics, we adapt selected methods to teach mathematics more effectively in the United States. Much of this approach is new to U. S. mathematics teachers, in that it has teachers working together in groups on lesson plans, and through a series of discussions and revisions, results in a greatly improved, effective plan. It also has teachers actively observing individual students or groups of students as they work on a problem, and then later comparing and discussing the students' work.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권7호
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• pp.1252-1273
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• 2011

In Web Service Composition (WSC) area, services selection aims at selecting an appropriate candidate from a set of functionally-equivalent services to execute the function of each task in an abstract WSC according to their different QoS values. In despite of many related works, few of previous studies consider transactional constraints in QoS-aware WSC, which guarantee reliable execution of Composite Web Service (CWS) that is composed by a number of unpredictable web services. In this paper, we propose a novel global selection-optimal approach in WSC by considering both transactional constraints and end-to-end QoS constraints. With this approach, we firstly identify building rules and the reduction method to build layer-based Directed Acyclic Graph (DAG) model which can model transactional relationships among candidate services. As such, the problem of solving global optimal QoS utility with transactional constraints in WSC can be regarded as a problem of solving single-source shortest path in DAG. After that, we present Graph-building algorithms and an optimal selection algorithm to explain the specific execution procedures. Finally, comprehensive experiments are conducted based on a real-world web service QoS dataset. The experimental results show that our approach has better performance over other competing selection approaches on success ratio and efficiency.

• 제어로봇시스템학회논문지
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• 제20권4호
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• pp.408-413
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• 2014

In this paper, we propose a fault diagnosis method based on Park's Vector Approach using the Euler's theorem. If we interpreted it as Euler's theorem, it is possible to easily find the phase angle difference between the healthy condition and the fault condition. And, we analyzed the variation of the phase angle and performed the diagnostic method of the induction motor using feature vectors that were obtained by using a Fourier transform. The analysis of time and speed variation of the motor was performed and, as a result, we could find more soft variations than rough variations. In particular, the analysis of the distortion through each phase shows that two-turn and four-turn shorted motors are linearly separable. In this experiment, we know that the maximum breakdown threshold value for determining steady-state fault detection is 49.0788. Simulation and experimental results show the more detectable than conventional method.

• Structural Engineering and Mechanics
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• 제69권4호
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• pp.361-369
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• 2019

The determination of Paris' law parameters based on crack growth experiments is an important procedure of fatigue life assessment. However, it is a challenging task because it involves various sources of uncertainty. This paper proposes a novel probabilistic method, termed the S-N Paris law (SNPL) method, to quantify the uncertainties underlying the Paris' law parameters, by finding the best estimates of their statistical parameters from the S-N curve data using a Bayesian approach. Through a series of steps, the SNPL method determines the statistical parameters (e.g., mean and standard deviation) of the Paris' law parameters that will maximize the likelihood of observing the given S-N data. Because the SNPL method is based on a Bayesian approach, the prior statistical parameters can be updated when additional S-N test data are available. Thus, information on the Paris' law parameters can be obtained with greater reliability. The proposed method is tested by applying it to S-N curves of 40H steel and 20G steel, and the corresponding analysis results are in good agreement with the experimental observations.

• The Korean Journal of Pain
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• 제9권1호
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• pp.126-129
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• 1996

Background: Advantages of paramedian approach over midline approach include less tissue trauma and less dependence on patient's ability to assume a fetal position. When midline approach fails in patients who are difficult to take a position with lumbar spine flexed, paramedian approach to interlaminar space may succeed. Methods: Success rates of spinal anesthesia were measured for 47 flexed patients by midline approach, 48 flexed patients by paramedian approach, 23 straightened patients receiving spinal anesthesia by midline approach, and 23 straightened patients by paramedian approach. Results: Success rates in flexed patients were 100% by midline approach and 100% by paramedian approach. Success rates for straightened patients were 13.0% by midline approach and 78.3% by paramedian approach. For straightened patients there were no correlations between success fate and age, weight, Ponderal Index but there were correlations between height and midline approach of spinal anesthesia. Conclusion: Pertaining to adult Koreans, success rates of spinal anesthesia for strainghtened patients were less than those for flexed patients. Success rate of paramedian approach of spinal anesthesia among strainghtened patients were better than those of midline approach.

• 한국항행학회논문지
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• 제18권4호
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• pp.288-295
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• 2014

현재 사용 중인 계기착륙장치(ILS)는 시스템 특성상 동시에 다수의 입항하는 항공기가 사용하기 어렵고, 활주로 방향별로 장비들이 설치되어야 한다. 또한 착륙하는 항공기들이 일정한 구역에서 단일 비행경로만으로 착륙절차가 구성되어야 한다는 한계점이 있다. 이에 항공 교통량이 증가하게 된다면 입항하는 항공기들의 체공 시간이 더욱 증가하게 될 것이다. 이러한 한계점을 보완하기 위해 GNSS를 이용한 착륙시설로 GBAS가 개발 되었다. 본 논문에서는 비행시험 전 시뮬레이터를 이용하여 태안 비행장에서 실제 사용 하고 있는 항공기 착륙절차와 Curved approach를 이용한 절차를 비교 하였다. 비교 결과 Curved approach 절차를 이용하게 되면 기존절차보다 비행시간이 감소되어 연료 및 소음공역회피 등과 같은 효과가 일어 날 수 있을 것으로 판단된다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제30권1호
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• pp.72-82
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• 2008

Various surgical approaches in the mandibular condyle fracture have been reported and many advantages of intraoral reduction were also introduced. But there are still controversies about surgical method of condylar fractures up to date. To establish the surgical approach protocol of condylar fracture, from May 2001 to December 2004, total 65 patients with 74 fractures of the mandibular condyle were reviewed during 2 years, retrospectively. All cases were classified according to the treatment considering factors, such as the level of fracture, degree and direction of displacement of fractured segment, patient’s age and gender, surgical approach methods, and their complications. Especially, advantages and surgical limitations of extraoral surgical approach, such as direct reduction and fixation via submandibular approach, Nam’s method, and endaural approach, were compared with those of intraoral surgical approach, such as direct intraoral reduction with transbuccal fixation or right angle driver system, and intraoral reinsertional approach after extraoral fixation of fractured fragment. The guidelines of surgical approach of condylar fracture based on our clilnical retrospective experiences and literature reviews can be suggested.

• 한국항공운항학회지
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• 제26권3호
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• pp.1-8
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• 2018

Aviation industry is growing rapidly, and this growth is expected to continue. However, aircraft accident rate is still high, and 65 percent of accidents occur during landing phase due to unstable approach. Therefore, this research analyzed causes and countermeasures of unstable approach. In order to derive countermeasures, this study selected P International Airport as an example case. In addition, this research analyzed A airline's FOQA data, regional Standard Operating Procedures, and 5 years of environmental factors to identified correlation of those contributing factors. In conclusion, his research concluded following results. First of all, because of P International Airport's geological features, pilots are required to conduct Circling Approach, and this advanced maneuver increases workload at the final stage of flight. Secondarily, meteorological factors such as crosswind, seasonal rain front, local visibility contributes unstable approach. Lastly, these geological and meteorological factors are interrelated, and this uncommon environment can decrease circumstantial judgement ability of pilots and jeopardize aviation safety. As a consequence, it is recommended to reinforce the Crew Resource Management and Threat & Error Management systems so that pilots can perceive identical safety target.