• Journal of Energy Engineering
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• v.2 no.1
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• pp.123-132
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• 1993

This work is focussed on the reduction of ethanol separation energy from alcohol fermented broth and categorized into the development of a computer program for the design of the pressurized/depressurized distillation process which has been regarded as one of the energy-reducing models for the conventional distillation process, the optimization of operating conditions of distillation towers by means of the developed program, and the evaluation of the total annual energy cost of pressurized/depressurized distillation columns compared with that of the conventional single distillation columns. The operating pressures are, in case of pressurized/depressurized distillation, 3103/760 mmHg, 3103/450 mmHg, 3103/160 mmHg, and in case of conventional distillation, 760 mmHg. The optimum reflex rations which the sum of the annual energy cost and the annual fixed cost for each process becomes minimum are 3.7475/2.9111 for the operating pressures of 3103/760 mmHg, 3.814/2.9712 for 3103/450 mmHg, 3.0783/2.2400 for 3103/150 mmHg, and 3.8544 for the atmospheric operating pressure. And the annual energy cost of pressurized/depressurized distillation process for the above-mentioned operating pressures is distributed between 42% and 47% of that of conventional distillation process.

• Journal of the Korean Geotechnical Society
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• v.15 no.3
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• pp.41-70
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• 1999

The benefits of utilizing internal reinforced members, such as soil nails and ground anchors, in maintaining stable excavations and slopes have been known among geotechnical engineers to be very effective. Occasionally, however, both soil nails and ground anchors are simultaneously used in one excavation site. In the present study, a method of limit equilibrium stability analysis of the excavation zone reinforced with the vertically or horizontally mixed nail-anchor system is proposed to evaluate the global safety factor with respect to a sliding failure. The postulated failure wedges are determined based on the results of the $FLAC^{2D}\; 및\; FLAC^{3D}$ program analyses. This study also deals with a determination of the required thickness of the shotcrete facing. An excessive facing thickness may be required due to both the stress concentration and the relative displacement at the interface zone between the soil nailing system and the ground anchor system. A simple finite element method of analysis is presented to estimate the corresponding relative displacement at the interface zone between two different support systems. As an efficient resolution to reduce the facing thickness, the modified bearing plate system is also proposed. Finally with various analysis related to the effects of design parameters, the predicted displacements are compared with the results of the $FLAC^{2D}$ program analyses.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1916-1932
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• 2008

The railway accident is characterized by widespread and great(immerse) damage to our society when an accident occurred even if the probability of a railway accident is low. It is no doubt that the role of a rolling stock driver who are active in the first line of the rail safety driving is the most important to prevent an unexpected railway accident. Before new railway safety law being taken into effect, each railway operating organization had the responsibility of training a rolling stock driver by qualification criteria (the requirements or standards of competency), training period, probation period decided on their own standards. To train drivers driving same locomotive model, each railway operating organization had a variety of standards to draft and train trainees. Consequently, It was considered inefficient way to train and manage rolling stock drivers. However, after implementing the new railway safety law, a new system including training and evaluation process to issue driver's license on the condition that entire requirements are satisfied has been established. To prove the competency of the rolling stock driver objectively, training center and third-party evaluation center are divided individually and assigned by government office. Training center should design the training program to allot theatrical education time for different trainee group and to secure maximum practical training time utilizing simulator system to enhance the rolling stock driver's competency. This study analyzes certain conditions necessary to maximize the effectiveness and practical use of training for aquisition of a driver's license and the problems of the existing rail safety law and the ways to improve them.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5284-5289
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• 2011

This study focused to evaluate thermal transmittance(U-value) performance of sliding type of aluminum alloy window frame(AAWF) with double glazing(DG) and glazing spacer and that without thermal breaker in winter and summer season by two dimensional steady state heat transfer analysis. The AAWE was installed to an existing educational facilities in Seosan area which is the southern region of the Korean Peninsula. Analysis of 2D steady-state heat transfer was performed through the use of BISCO as calculation and simulation program. U-value and temperature factors were calculated. The results are as followed. First, the isotherm simulation shows that AAWF with double glazing have serious differences from recently proposed window thermal performance standards such as Insulation Performance of Windows and Doors of Building Energy Saving Design Standards and the results of calculation of thermal transmittance performance of AAWF and DG are U=9.631 W/$m^2K$, U=2.382 W/$m^2K$ respectively during winter and summer season. Second, the results of analysis of heat transfer analysis, calculated by simulation, shows that 225% of heat is lost comparing with thermal performance standards U=4.0 W/$m^2K$ of general double glazing among those standards on AAWF without thermal breaker.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.1
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• pp.66-71
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• 2006

Lately teaching-learning system on the web site offers broad educational environment without any restriction of time and place to the teachers and learners. Using a web site in music education turned out to be effective. It provokes learner's interest and guides self-directed learning. Therefore, on this research, the web site for self-directed learning in music subject was designed and embodied as an assistant material of learning which is suitable for learner's level and demand As a result of using the web site in music class, there are some responses of students. First, there were 27 students positive responses$(79.4\%)$ of 34 students in the learning effect of the web site, and 25 students$(73.5\%)$ of 34 showed their will to use the web site continually if it is modified and supplemented. Second, some students answered that using this program in Diagnosis Evaluation and Formative Test could have an instant result, which was used for the material of feedback. Third, there was a positive evaluation of helping self-directed learning.

• Journal of Elementary Mathematics Education in Korea
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• v.14 no.1
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• pp.81-102
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• 2010

The purpose of this study was to analyze the content and design of the seven math camp programs for students of the education centers for the elementary gifted students. The analysis focused on the goals, content, and evaluations utilized in the math camp programs. The results of the study were as follows. First, there was no big difference between the goals set for each camp, and they mainly focused on the goals in affective domain. Second, the content of math camp programs was focused on enrichment rather than acceleration. Most of the programs were focused on geometry, whereas fewer programs were focused on measurement, probability and statistics. Based on the Analysis, we found that only nine out of 27 programs applied level-wised or individual exercise programs. Third, all centers for the mathematically gifted carried out evaluations of their math camp programs. However, a specific evaluation plan was not established for the math camp program plans. We suggested the direction of math camp programs as follows. First, the goals should reflect on the intended outcomes of the math camp programs. Also, the goals of math camp programs need to be distinctive from general education goals. Second, the programs should contain harmonious contents with enrichment and acceleration and must include various reactions and task commitment. The math camp programs need to include references and an appropriate information for the gifted students to encourage self-directed learning. Third, a more specific evaluation plan for math camp programs needs to be developed for effective education for the gifted students.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.639-645
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• 2018

The objective of this research was to compare the precision of scanning the digital abutment impression and gypsum model according to 3-dimensional superimposing different skills. There were made with the abutment impression and gypsum model of a maxillary 1st premolar, blue light scanner scanned to obtain the stereolithography (STL) file. After the same process was performed 10 more times without moving them on the scanner table about the abutment impression and gypsum model, respectively (n=11, per types). By superimposing the date of scanning the abutment impression and gypsum model used with no control and best-fit-alignment skills, 10 color-difference maps and root mean square (RMS) data were obtained. The independent t-test was performed to compare RMS data between the each other groups (${\alpha}=0.05$). In the scanning abutment impressions, $RMS{\pm}SD$ of no control, best-fit-alignment showed $6.86{\pm}0.94$, $5.04{\pm}0.24$. in the scanning gypsum model, $4.98{\pm}1.16$, $3.39{\pm}0.07$, all groups showed a significant difference (P<0.001). Trough the this study's result, not only best-fit-alignment but no control is used with digital dental computer-aided design/computer-aided manufacturing (CAD/CAM) research and clinical part.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1275-1282
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• 2012

Helicopter rotor systems are dynamically loaded structures with many composite components such as the main and the tail rotor blades. The fatigue properties of composite materials are extremely important to design durable and reliable helicopter rotor blades. The safe-life methodology has generally been used in the helicopter industry to substantiate dynamically loaded composite components. However, it cannot be used to evaluate the strength reducing effects of flaws and defects that may occur during manufacturing and operational usage. The damage tolerance methodology provides a proper means to overcome this shortcoming; however, it is difficult to economically apply it to every composite component. The flaw tolerant methodology is an equivalent option to the damage tolerance methodology for civil and military rotorcraft. In this study, the flaw tolerant safe-life evaluation is described and illustrated by means of successful application to substantiate the retirement time of composite rotor blades.

• Journal of Hospice and Palliative Care
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• v.22 no.4
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• pp.185-197
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• 2019

Purpose: Hospice volunteers are serving an invisible yet pivotal role in the hospice and palliative care team. This study investigated how effectively a continuing education program could enhance hospice volunteers' competency. Methods: A total of 20 hours (four hours per week) of training was provided to 30 hospice volunteers who participated in the continuing education for hospice volunteers. Efficiency of the education was analyzed with an exploratory mixed-methods design. For quantitative analysis, the volunteers were asked, before and after the training, about their attitudes towards hospice care, what makes a meaningful life, self-efficacy and satisfaction with their volunteer service. Descriptive statistics, paired t-tests, and Wilcoxon signed-rank test were performed using SPSS Window 20.0. For qualitative research, participants were placed in three groups for a focus group interview, and data were analyzed by content analysis. Results: A quantitative study result shows that this training can significantly affect hospice volunteers' attitudes and improve their self-efficacy. A qualitative study result shows that participants wanted to receive continuous education from the physical/psychosocial/spiritual aspects to better serve end-of-life patients and their family members even though they have to spare significant time for the volunteer service. They wanted to know how to take good care of patients without getting themselves injured and how to provide spiritual care. Conclusion: The continuing education program reflecting volunteers' requests is strongly needed to improve their competency. An effective continuing education requires continuous training and support in areas where hospice volunteers are interested in. A good alternative is to combine web-based and hands-on training, thereby allowing hospice volunteers freely take training that suits their interest.

• Journal of dental hygiene science
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• v.15 no.4
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• pp.393-398
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• 2015

One of the most critical causes in determining the clinical outcomes of dental prostheses is the validity of models. However, studies that evaluated validity of digital models are few. The objectives of this study were to evaluate validity of edentulous digital models for full denture fabrication. Twenty stone models (edentulous model) were manufactured and scanned by dental blue light emitting diode scanner. Twenty digital models were manufactured. Six linear distances (inter-canine distance, inter-molar distance, two dental arch lengths (right, left), two diagonal of dental arch lengths (right, left) were measured for validity evaluation. The measurements of distances of stone models were used by digital vernier caliper and digital models were used by computer program. The mean${\pm}$deviations values of six distances were calculated. The means were compared by the Mann Whitney U test (${\alpha}=0.05$). All statistical analysis were performed using IBM SPSS Statistics ver. 20.0. Although digital models were smaller than stone models in six distances, there were no significant differences (p>0.05) and non exceeded the clinical acceptable range. The edentulous digital models for full denture fabrication can be considered clinically acceptable.