• Journal of the Earthquake Engineering Society of Korea
• /
• v.7 no.3
• /
• pp.9-15
• /
• 2003

This paper presents a design procedure for viscoelastic dampers to be installed in a full-scale steel structure and observes their vibration control effect, based on the excitation method and the dynamic characteristics of the structure investigated in the companion paper, Additional damping ratios required to reduce the maximum displacement to a given level were obtained by convex model. The size of dampers was determined by observing the change in modal damping ratio due to the change in damper stiffness using the modal strain energy method, The effect of the supporting braces was also considered in the determination of the modal properties. Two viscoelastic dampers were installed at the first and second inter-stories, respectively and their response reduction is verified.

• KIPS Transactions on Software and Data Engineering
• /
• v.6 no.7
• /
• pp.353-360
• /
• 2017

In this study, a software education program based on blended learning using scratch was designed for pre-service elementary teachers' software education. Software education program was applied to experimental group and control group within the university of education using Scratch programming for 12 weeks. Blended learning using online lectures was applied to experimental group. The pre-service teachers' recognition about software education and self-evaluation of computational thinking were performed. Then, we analyzed the effect of the developed education program on the recognition of software education and computational thinking. As a result, the level of post-recognition of software education in the experimental group was significantly higher than that of the pre-recognition. In the self-evaluation of computational thinking, the experimental group was significantly higher than the control group. Therefore, it can be seen that the software education program based on blended learning can help improve the learner's computational thinking.

• The Journal of the Acoustical Society of Korea
• /
• v.29 no.2
• /
• pp.118-124
• /
• 2010

In this paper, design parameters of dynamic vibration absorber, which is used to reduce bending vibrations of a vehicle drive line, is optimized. For obtaining the correct dynamic response characteristics, a flexible-body drive line is made by applying the flexibility data extracted from vibration analysis of propeller shafts to the drive line dynamic model. Inner tube mass, rubber stiffness and rubber damping coefficient of the dynamic vibration absorber are taken as design parameters for optimization. To minimize the vertical acceleration of the drive line, a second-order regression equation of the objective function is generated by performing the central composite experimental design with 3 factors, 2 levels and 15 test runs. And the design parameters of the dynamic vibration absorber are determined by using optimization program. The vehicle model with optimized dynamic vibration absorber reduces the vertical acceleration peak of the drive line by 17.1 % in compared with the initial model.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.40 no.5
• /
• pp.140-147
• /
• 2012

This study developed a flowerbed type infiltration system that could control the amount of runoff discharge under a certain level estimated its proper design infiltration rate, and analyzed the effects of its implementation. Analyzing the performance of infiltration system is the one of the essential processes that should be under review to predict its effects after implementation when a rainwater infiltration system is included in a district-based plan. To estimate the unit design infiltration rate of this system, the runoff decrease effect was analyzed by varying the unit infiltration rate of the system applied to the parking lot adjacent to the Korea Institute of Construction Technology laboratory building by using a water balance analysis program. After varying the unit design infiltration to $0.1{\sim}3m^3/m^2.day$ to analyze the variation in the rate of runoff, 80% of the runoff was infiltrated at $1.0m^3/m^2.day$, and the unit infiltration design rate at the time was 0.0416(m3/m2.hr). It was also found that the unit design infiltration rate obtained from a field infiltration test of the developed system was about $0.045m^3/hr$. Based on this study, it was possible that infiltration rate is estimated to consider the economic scale and environmental effect. It is significant to apply the spatial plan of rainwater infiltration system as green infrastructure.

• 한국체육학회지인문사회과학편
• /
• v.58 no.4
• /
• pp.447-459
• /
• 2019

This study was conducted to investigate the differences between emotional responses and neurotransmitters in moderate-intensity continuous exercise (MICE) and high-intensity interval exercise (HIIE) in 30 low-active women. Both groups performed a designed acute treadmill exercise and repeated the same exercise three times at intervals of one week. MICE performed a 25-minute continuous exercise at 90% VT(ventilation threshold) after a 5-minute warm-up session at 50% VT and then cooled down for 5 minutes at 50% VT level. The HIIE was repeated 6 times for 2 minutes at 115% VT level, and the intermediate active recovery was repeated 4 times for 2 minutes at 85% VT level. The results of the statistical analysis are as follows. MICE was showed positive effect for feeling scale and PACES after exercise in the first experiment, but negative effect in the third experiment. Conversely, HIIE was showed negative effect for feeling scale and PACES after exercise in the first experiment, but positive effect in the third experiment. Neurotransmitters were significantly increased in all three groups after 10 minutes of exercise compared to before exercise. In summary, HIIE exercise may be a strategy to increase exercise compliance for low-active women.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2010.04a
• /
• pp.645-648
• /
• 2010

논문에서는 부착식 텐던 격납건물의 유효긴장력 평가를 위해서 제작된 테스트 빔에 대한 고유진동수 해석을 수행하였고, 그 결과를 기술하였다. 제작된 테스트 빔은 원전 격납건물의 1/5 축소모형으로 설계하였고, 긴장력 수준을 5가지로 분류하여 실험에 의한 고유진동수와 SI(System Identification)기법을 위하여 모델링한 3차원 유한요소해석에 의한 고유진동수를 비교 분석하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 1999.11a
• /
• pp.525-529
• /
• 1999

본 논문에서는 고속 FPGA 설계를 위한 논리 수준의 조합회로 합성 알고리듬을 제안한다. 제안 된 알고리듬은 회로의 지연시간을 줄이기 위해 critical path를 분할한 후 분할된 회로를 동시에 수행하는 구조의 회로를 생성한다. MCNC 표준 테스트 회로에 대한 실험에서 제안된 지연시간 최적화 알고리듬이 기존 알고리듬에 비해 지연시간이 평균 33.3 % 감소된 회로를 생성함을 보였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.972-975
• /
• 2004

In order to reduce the noise of BLDC motor, a systematic optimization procedure for rotor structure is presented. The noise index is defined as the sum of volume velocity of FE-model that are calculated at the dominant frequencies during dehydration process, which is based on the principle of radiation simple volume source. Then, the five design variables are selected to represent the shape and layout or rotor structure. This discrete design optimization problem for minimizing the noise index is solved by 3-level orthogonal array based effect analysis. Finally, the response surface method (RSM) combined optimization approach is employed for more refining the approximate optimum.

• The KIPS Transactions:PartD
• /
• v.13D no.3 s.106
• /
• pp.425-436
• /
• 2006

The e-learning system in which the learning is carried out by predefined procedures cannot offer proper learning suitable to the capability of individual learner. To solve this problem, SCORM sequencing can be used to define various learning procedures according to the capabilities of learners. Currently the sequencing is designed by teachers or learning contents producers to regularize the learning program. However, the predefined sequencing may not reflect the characteristics of the learning group. If inappropriate sequencing is designed it may cause the unnecessary repetition of learning. In this paper, we propose an automated evaluation system in which dynamic sequencing is applied. The dynamic sequencing reflects the evaluation results to the standard scores used by sequencing. By changing the standard scores, the sequencing changes dynamically according to the evaluation results of a learning group. Through several experiments, we verified that the proposed learning system that uses the dynamic sequencing is effective for providing the proper learning procedures suitable to the capabilities of learners.

• The Journal of Korean Academy of Sensory Integration
• /
• v.15 no.1
• /
• pp.21-32
• /
• 2017

Objective : The purpose of this study is to explore the effectiveness of a perceptual motor program in promoting visual motor and motor control outcomes in a child with Attention-Deficit/Hyperactivity Disorder (ADHD) who is enrolled in an elementary school. Methods : The subject is 8-year-old boy who was diagnosed with ADHD but did not receive medication. Research design is a single-subject A-B-A(follow-up). Baseline and follow-up phase were 3 sessions and intervention phase were 8 sessions. After performing 40 minutes of free play on the baseline A and follow-up A, we used the copying subtest of the Korean Development Test of Visual Perception 2 (K-DTVP-2) for evaluating visual motor integration skill and the rope jumping subtest for motor skill. After providing the perceptual motor activity in intervention phase B, copying and ropejumping were performed. Results : The standard scores of the Copying for measuring visual motor integration skill were poor at an average of 4.7 points at baseline phase A, but maintained an average of 9.6 points at intervention phase B and an below average of 7.7 points at the follow-up phase A. In the Rope jumping for the motor skill, it was increased by 4.3 times in the baseline phase A and 5.9 times in the intervention phase B, but slightly decreased by 5 times in the follow-up phase A. Conclusion : This study suggests that perceptual motor program has a positive effect on visual motor and motor function of ADHD children.