• International Journal of Highway Engineering
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• v.2 no.1
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• pp.147-156
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• 2000

Compaction is known to critically affect pavement performance. Due to its importance, a theoretical modelling of compacted density in the term of number of roller coverages is attempted by assuming compaction process essentially identical to pavement rutting. Excellent data fittings by the developed equation may prove the validation of assumptions made as well as justification of its use. According to the derived equation, a plot of density difference with respect to number of roller coverages in the logarithmic scale Produces a linear relationship. However, this linearity is turned out to be deviated by cooling effect, change of amplitude and frequency. Investigation of these three factors proposes a new generalized compaction density equation, which shows a promising future. By applying this general formula, the equations for the number of roller coverages required and the final compaction density obtained for a particular compaction project is derived first time in compaction research.

• Journal of the Korean Geotechnical Society
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• v.34 no.6
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• pp.37-47
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• 2018

In this study, 34 laboratory load test data were collected, and analyzed to propose the equations for predicting ultimate bearing capacity of sand compaction pile (SCP) and gravel compaction pile (GCP) reinforced clay. The collected data were compared with the ultimate bearing capacity estimated by existing theoretical equations, and the prediction accuracy of the existing theoretical equations was identified. Also, multiple regression analysis was performed to predict the ultimate bearing capacity, and the most efficient number and type of input variables were selected through error evaluation by leave-one-out cross validation. Finally, the multiple regression equations for estimating the ultimate bearing capacity of laboratory load test for SCP and GCP were proposed, and their performance was evaluated.

• Journal of Preventive Medicine and Public Health
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• v.56 no.1
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• pp.12-20
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• 2023

Quantitative and qualitative research explore various social phenomena using different methods. However, there has been a tendency to treat quantitative studies using complicated statistical techniques as more scientific and superior, whereas relatively few qualitative studies have been conducted in the medical and healthcare fields. This review aimed to provide a proper understanding of qualitative research. This review examined the characteristics of quantitative and qualitative research to help researchers select the appropriate qualitative research methodology. Qualitative research is applicable in following cases: (1) when an exploratory approach is required on a topic that is not well known, (2) when something cannot be explained fully with quantitative research, (3) when it is necessary to newly present a specific view on a research topic that is difficult to explain with existing views, (4) when it is inappropriate to present the rationale or theoretical proposition for designing hypotheses, as in quantitative research, and (5) when conducting research that requires detailed descriptive writing with literary expressions. Qualitative research is conducted in the following order: (1) selection of a research topic and question, (2) selection of a theoretical framework and methods, (3) literature analysis, (4) selection of the research participants and data collection methods, (5) data analysis and description of findings, and (6) research validation. This review can contribute to the more active use of qualitative research in healthcare, and the findings are expected to instill a proper understanding of qualitative research in researchers who review qualitative research reports and papers.

• Journal of Korean Medical Ki-Gong Academy
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• v.15 no.1
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• pp.1-22
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• 2015

Objectives : The purpose of this study is to develop a Gi-Gong method instruction configured with modern motions to suit the Medical curing characteristics of Korean Medicine and improve the development and validation of educational and clinical needs. Methods : We took survey on 33 students after giving 'Yang-Seng Gi-Gong' lectures at Woosuk University School of Korean Medicine in the first semester of the year 2015. Results : 1. Reflection of training goal was 7.75±1.79, which showed that the education was overall interesting, but showed a high satisfaction with the practical rather than the theoretical lectures. 2. General difficulty level was intermediate, but the practice of Hwal-In-Shim-Bang Do-In-Beop from several formulations were evaluated relatively difficult exercise. 3. The propriety of training materials were rated as mostly adequate, but that assessment was relatively less appropriate for the linkage of theory and practice, and that of time allocation and place was a normal level. 4. For the propriety of time distribution, the class of one semester such as the current is rated appropriate by 61% of students. 5. General class participation was 6.34±2.52, then participation in practice than theory lessons were active. On the other hand, Induction training participation and participation appeared to be relatively low correlation, but overall interesting and participation in practice high correlation. Conclusions : The difficulty level of theory lessons is necessary to be adjusted and lecture form will need to continue focusing on practical lessons.

• Steel and Composite Structures
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• v.27 no.1
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• pp.109-122
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• 2018

In This work an analysis of the propagation of waves of functionally graduated plates is presented by using a high order hyperbolic (HSDT) shear deformation theory. This theory has only four variables, which is less than the theory of first order shear deformation (FSDT). Therefore, a shear correction coefficient is not required. Unlike other conventional shear deformation theories, the present work includes a new field of displacement which introduces indeterminate integral variables. The properties of materials are supposed classified in the direction of the thickness according to two simple distributions of a power law in terms of volume fractions of constituents. The governing equations of the wave propagation in the functionally graded plate are derived by employing the Hamilton's principle. The analytical dispersion relation of the functionally graded plate is obtained by solving an eigenvalue problem. The convergence and the validation of the proposed theoretical numerical model are performed to demonstrate the efficacy of the model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.361-369
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• 1996

The accurate prediction of modal parameters of a rotating blade is an important requirement in the assessment of the dynamics of a helicopter rotor. Indeed, predictions of flight loads and stability are normally dependent on initially predicting the undamped mode shapes. A measuring technique, known as Strain Pattern Analysis (SPA), appears to be the most successful technique for measuring the mode shapes of rotating blades. This method was developed to be used on actual aircraft so no attempt was made to measure rotating mode shapes directly in order to validate the SPA method. This report summarizes results from experimental investigations which were carried out to validate the SPA method for the prediction of aerodynamically damped modes of a rotating blade. A series of modal tests were carried out on two rotor models in which the non-rotating, undamped and aerodynamically damped rotating modes were measured directly (strain and displacement patterns). It is shown that the SPA method to be very successful in itself but there are a number of limitations in validating this technique. To provide data which could be used to confidently validate theoretical prediction codes, existing limitations should be addressed.

• Structural Engineering and Mechanics
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• v.65 no.6
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• pp.699-706
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• 2018

In the present contribution, fracture resistance of U-notched GPPS members under mixed mode I/III loading conditions is assessed by using the Averaged Strain Energy Density (ASED) criterion. This criterion has been founded based on the ASED parameter averaged over a well-defined control volume embracing the notch edge. The validation of the theoretical criterion predictions is evaluated through comparing with the results of a series of mixed mode I/III fracture tests conducted on rectangular-shaped GPPS specimens weakened by a single edge U-notch. A recently developed apparatus for mixed mode I/III fracture experiments is employed for measuring the fracture loads of the specimens. The test samples are fabricated with different notch tip radii with the aim of evaluating the influence of this major feature of the U-notched components on the mixed mode I/III fracture behavior. It is shown that the onset of brittle fracture in U-notched GPPS specimens under various combinations of tension and out-of-plane shear can well be predicted by means of the ASED criterion.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.28.4-29
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• 2008

The aim of the test is to provide an experimental basis to validate the prediction of the FEM for high frequency jitter analysis due to reaction wheel. The principle is to measure structural transfer functions between the input disturbances at RWA base plate and the accelerations near the end tips of payload, in a configuration close to the operational model. The spacecraft shall have to be suspended, in order to be representative of on-orbit boundary conditions. The results of the test shall be compared to the output of the FEM analysis, and if needed, local upgrades of the FEM and/or margin policy shall be defined in order to guarantee a good test/FEM consistency. Test results were compared with the transfer functions of the FEM, which is globally tuned based on the results of vibration test and consequently have lower damping coefficients values than 1% in the frequency range of 60~200Hz. The damping coefficients estimated from the figures of FRF test results are different from the theoretical FEM, but the magnitude trend of FRF of the test results is somewhat similar with the analytical, it is expected that the overall jitter effect of final estimation is nearly same with the preliminary analysis result in which the damping coefficients were assumed to be 1% for all modes in FEM.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.35.3-36
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• 2008

The ground-based spacecraft simulator is a useful tool to realize various space missions and satellite formation flying in the future. Also, the spacecraft simulator can be used to develop and verify new control laws required by modern spacecraft applications. In this research, therefore, Hardware-in-the-loop (HIL) simulator which can be demonstrated the experimental validation of the theoretical results is designed and developed. The main components of the HIL simulator which we focused on are the thruster system to attitude control and automatic mass-balancing for elimination of gravity torques. To control the attitude of the spacecraft simulator, 8 thrusters which using the cold gas (N2) are aligned with roll, pitch and yaw axis. Also Linear actuators are applied to the HIL simulator for automatic mass balancing system to compensate for the center of mass offset from the center of rotation. Addition to the thruster control system and Linear actuators, the HIL simulator for spacecraft attitude control includes an embedded computer (Onboard PC) for simulator system control, Host PC for simulator health monitoring, command and post analysis, wireless adapter for wireless network, rate gyro sensor to measure 3-axis attitude of the simulator, inclinometer to measure horizontality and battery sets to independently supply power only for the simulator. Finally, we present some experimental results from the application of the controller on the spacecraft simulator.

• Culinary science and hospitality research
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• v.8 no.1
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• pp.71-94
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• 2002

The food service industry has grown up without an affection of economic collapse, and its kinds are being diversified and focused on many different aspects from physical taste to many other elements such as atmosphere, service quality, sanitation and etc.. Now it appeals to even familiarity. These Facts are well ref looted to Family Restaurant which has not been very popular so far, but now it takes its space in the market, and its management system is being introduced to other countries. The purpose of this study is to see how to satisfy them to make maximum business profit, and one possibility is "incentive". To accomplish research, theoretical and practical studies have been done and surveys have taken placed for substantial studies. The subjects were limited to employees in Family Restaurant in Seoul from February 20th to March 20th, 2001. Data, reliableness, and propriety were analyzed by SAS(Statistical Analyzed System). Sampling mode was randomness, and validation mode was limited to 223 papers. The followings are the results of this analysis First, Satisfaction of incentive were made by stability, impartiality and suitability regardless difference on companies, ages, departments, and authority of an employees. Second, Satisfaction on incentive for employees in Family Restaurants were not well received. Although these necessary demand, there is not yet incentive system operation to most of business. Especially, it is not even studied on Family Restaurants. This study should have been studied on more customers and spotted employees to be objective. It is strongly recommended to do this study without limitation and further studies is considered on this subjects.