• The Journal of the Korea Contents Association
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• v.5 no.3
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• pp.193-199
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• 2005

One of the important fields for heuristics algorithm is how to balance between Intensificationand Diversification. Ant Colony System(ACS) is a new meta heuristics algorithm to solve hard combinatorial optimization problem. It is a population based approach that uses exploitation of positive feedback as well as greedy search. It was first proposed for tackling the well known Traveling Salesman Problem(TSP). In this paper, we propose Multi Colony Interaction Ant Model that achieves positive negative interaction through elite strategy divided by intensification strategy and diversification strategy to improve the performance of original ACS. And, we apply multi colony interaction ant model by this proposed elite strategy to TSP and compares with original ACS method for the performance.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.1
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• pp.33-42
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• 1997

The reciprocating compressors are widely used in industrial fields for its simplicity in principle and high efficiency. But the design of it requires rigorous experiments due to its high dependence on many design parameters. In this work, a mathematical model is developed so that we can analyze the gas-solid interaction during the whole working processes of a reciprocating compressor. The governing equations, which represent the fluid-solid interaction, was derived from the unsteady Bernoulli's equation with the assumption of quasi-steady working process. The valve itself was assumed to be a one degree of freedom spring-mass-damper system. A simple thermodynamic relation, the ideal gas state equation, was used to give it an external force term assuming that the refrigerant behaves like an ideal gas. It was suggested to use a motor of higher driving frequency to enhance the performance of the reciprocating compressor without causing a faster failure of the valve.

• Structural Engineering and Mechanics
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• v.77 no.6
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• pp.721-734
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• 2021

The seismic analysis of structures without applying the effects of soil can undermine functional objectives of structure so that it can affect all the desired purposes at the design and control stages of the structure. In this research, employing OpenSees and MATLAB software simultaneously and developing a definite three-dimensional finite element model of a high-rise concrete structure, designed using performance-based plastic design approach, the performance of Tuned Mass Damper (TMD) and Active Mass Damper (AMD) is both examined and compared. Moreover some less noted aspects such as nonlinear interaction of soil and structure, uplift, nonlinear behavior of structure and structural torsion have received more attention. For this purpose, the analysis of time history on the structural model has been performed under 22 far-field accelerogram records. Examining a full range of all structural seismic responses, including lateral displacement, acceleration, inter-story drift, lost plastic energy, number of plastic hinges, story shear force and uplift. The results indicate that TMD performs better than AMD except for lateral displacement and inter-story drift to control other structural responses. Because on the one hand, nonlinear structural parameters and soil-structure interaction have been added and on the other hand, the restriction on the control force applied that leads up to saturation phenomenon in the active control system affect the performance of AMD. Moreover, the control force applied by structural control system has created undesirable acceleration and shear force in the structure.

• Journal of Advanced Research in Ocean Engineering
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• v.1 no.2
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• pp.73-84
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• 2015

The turbine is one of the most important components in the tidal current power device which can convert current flow to rotational energy. Generally, a tidal turbine has two or three blades that are subjected to hydrodynamic loads. The blades are continuously deformed by various incoming flow velocities. Depending on the velocities, blade size, and material, the deformation rates would be different that could affect the power production rate as well as turbine performance. Surely deformed blades would decrease the performance of the turbine. However, most studies of turbine performance have been carried out without considerations on the blade deformation. The power estimation and analysis should consider the deformed blade shape for accurate output power. This paper describes a fluid-structure interaction (FSI) analysis conducted using computational fluid dynamics (CFD) and the finite element method (FEM) to estimate practical turbine performance. The loss of turbine efficiency was calculated for a deformed blade that decreased by 2.2% with maximum deformation of 216mm at the blade tip. As a result of the study, principal causes of power loss induced by blade deformation were analysed and summarised in this paper.

• The Journal of Korean Physical Therapy
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• v.11 no.1
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• pp.87-93
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• 1999

The purpose of this study were to compare the balance performance with 44 children, who aged 6 and 7years old by means of the Pediatric Clinical Test of Sensory Interaction for Balance(PCTSIB), second is to determine whether age and gender-relatad difference were present, third is to found correlation of weight, height with duration of balance performance. All subjects were performed with different foot position that were feet-together, heel-toes. The starting position was that subject placed their hands on the hips. The results of each test were measured by stop watch. These collected data were analyzed by using oneway ANOVA, Sheffe test t-test and correlation. The results of this study were as follows ; 1. There were all significiant difference is all instances except condition 4 with heel-toes(p<0.05). The duration of balance performance of 7-year-olds group was more increased than 6-year-olds group. 2. There was statistically significiant difference in all instances by gender(p<0.05). 3. There was no correlation between weight or height duration of balance performance (p<0.05).

• The Journal of the Korea Contents Association
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• v.17 no.4
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• pp.468-477
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• 2017

The purpose of this study was to exam nursing students to verify the effects of self-directed learning readiness, teacher-student interaction, educational performance, stress and learner motivation on learner satisfaction. The study population consisted of second and third year nursing students at E university located in S city. Data were collected between June 15, 2016 to June 24, 2016, and questionnaire comprised items to measure general characteristics, learner motivation, teacher-student interaction, self-directed learning readiness, educational performance, and learner satisfaction. A total of 132 students were included for the final analysis. Learner satisfaction was positively correlated with self-directed learning readiness (r= .21, p= .018), teacher-student interaction (r= .39, p<.001), educational performance (r= .21, p= .014), and learner motivation (r= .75, p<.001). In addition, learner motivation was positively correlated with self-directed learning readiness (r= .24, p= .005), teacher-student interaction (r= .38, p <.001), and educational performance (r= .21, p= .018). Finally, learner motivation and teacher-student interaction were found to explain 59.7% of the variance of learner satisfaction. Our findings suggest strategies and interventions that boost learner motivation and teacher-student interaction which are required to improve learner satisfaction in nursing education.

• Structural Engineering and Mechanics
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• v.33 no.4
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• pp.529-537
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• 2009

A key parameter in the design of a laterally loaded pile is the determination of its performance level. Performance level of a pile is usually expressed as the maximum head deflection and bending moment. In general, uncertainties in the performance of a pile originates from many factors such as inherent variability of soil properties, inadequate soil exploration programs, errors taking place in the determination of soil parameters, limited calculation models as well as uncertainties in loads. This makes it difficult for practicing engineers to decide for the reliability of laterally loaded piles both in cohesive and cohesionless soils. In this paper, limit state functions and consequent performance functions are obtained for single concrete piles to predict the maximum bending moment, a widely accepted design criterion along with the permissible pile head displacement. Analyses were made utilizing three dimensional finite element method and soil-structure-interaction (SSI) effects were accounted for.

• Journal of Korean Institute of Industrial Engineers
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• v.42 no.1
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• pp.57-64
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• 2016

Pen-based interaction is universally available on smart devices and especially on Tablet PCs. Previous studies compared various input methods like fingers, a mouse or a stylus pen on PCs or on a touchscreen based devices such as smart phones. At the same time, various soft keyboard applications are being developed on application stores of smart devices. However, these previous studies did not suggest which one is a suitable keyboard application for Tablet PCs when users perform a certain interaction as input type. In this study, we compared two types of input methods (finger and pen) and three types of soft keyboard applications (QWERTY, Gesture and Swype) in a Tablet PC using performance measurements (accuracy and input speed) and discussed what types of applications showed better performance with each interaction on tablet PC. From these results, recommendations for the keyboard types depending on the input methods on tablet PCs were developed.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.33-40
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• 2002

The hydraulic performance analysis of a pump system composed of an inducer and impeller for the application on turbopumps has been performed using three-dimensional Wavier-Stokes equations. A simple mixing-plane method and a full interaction method are used to simulate inducer/impeller interactions. The computations adopting two methods show almost similar results due to the weak interaction between the inducer and impeller since the inducer outlet blade angle is rather small. But, because the inducer and the impeller are closely spaced near the shroud region at the interface, flow angles at the impeller inlet show different results between two methods. Thus, the full interaction method predicted about $2\%$ higher pump performance than the mixing-plane method. And the effects of prewhirl at the impeller inlet are also investigated. As the inlet flow angle is increased, the head rise and the efficiency are decreased. The computational results are compared with experimental ones. The computational results at the design point show good agreements with experimental data. But the computation was found to under-predict the head rise at high mass flow rates compared to the experiment, further study must be followed in terms of the computation and experiment.

• Korean Medical Education Review
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• v.19 no.2
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• pp.83-89
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• 2017

The aim of this study is to examine the effect of recorded video monitoring on students' self-reflection after completing their clinical performance examination. Taking into account the particular cases involved in the examination, the present study utilized history-taking, physical examination, and patient education as bases for evaluating information-establishment ability, and asking, listening, understanding, explaining, and connectedness as the bases for evaluating patient-physician interaction ability. Student self-monitoring through recorded video feedback was carried out three days after completion of their clinical performance examination. Students self-evaluated their performance with a 10-point scale before and after self-monitoring. The results of this study show that students have a general tendency to lower their own self-evaluation scores after self-monitoring. Although there was not a statistically significant change of interrelationship in the information-establishment ability evaluation, there was a meaningful change of interrelationship in the patient-physician interaction ability evaluation after self-monitoring; specifically, in the case of acute lower abdominal pain, a high correlation was found (r=0.31, p=0.02) between the evaluation scores of standardized patients and students related to patient-physician interaction ability. This implies that self-monitoring enables the students to acquire a reflective viewpoint from which to evaluate their own performance. Therefore, it can be said that self-monitoring through recorded video feedback is a valuable method for students to use in reviewing their performance in patient-physician interactions.