Dynamic numerical simulation of pile-supported slab track system embedded in a soft soil and embankment was performed. 3D model was formulated in a time domain to consider the non-linearity of soil by utilizing FLAC 3D, which is a finite difference method program. Soil non-linearity was simulated by adopting the hysteric damping model and liner elements, which could consider soil-pile interface. The long period seismic loads, Hachinohe type strong motions, were applied for estimating seismic respose of the system, Parametric study was carried out by changing subsoil layer profile, embankment height and seismic loading conditions. The most of horizontal permanent displacement was initiated by slope failure. Increase of the embedded height and thickness of the soft soil layer leads increase of member forces of PHC piles; bending moment, and axial force. Finally, basic guidelines for designing pile-supported slab track system under seismic loading are recommended based on the analysis results.

본 연구에서는 보다 넓은 범위에서 영상기반 변위계측 시스템의 동특성 추정 신뢰성을 확보하기 위해 Shaking Table을 이용해 넓은 대역의 진동수와 진동수별 다양한 진폭에 대한 Sine Wave 동적실험을 실시하였다. 영상기반 변위계측을 위해 DDVS(Dynamic Displacement Vision System) 기법을 활용하였으며, DDVS 기법을 통해 구한 동적변위는 기존의 접촉·비접촉식 센서인 LVDT(Wire Type, Pole Type)과 LDS의 변위계측 결과와 비교하여 그 오차를 분석하였다. 구해진 동적변위를 FFT하여 진동수 영역에서의 정확도 비교도 함께 수행하였다. 4가지 타입의 계측센서 모두 동적변위계측 결과 최대 변위 도달 및 주기 운동 계측에 있어 대체적으로 유사한 결과를 나타냈으며, 특히 영상기반의 DDVS 기법과 LDS를 통한 계측 결과는 높은 상호 일치성을 보였다. LDS와의 비교를 통한 오차분석 결과, DDVS 기법에 의한 동적변위 계측의 정확도는 계측 대상의 진동수에 영향을 받는다고 판단되었다. 동일 가진 진동수 내에서 가해준 변위 변화에 의한 오차는 미미하였으나, 동일 발생 변위에서는 가진 진동수가 커질수록 오차 값이 증가하였다. 기존 센서인 LVDT 경우, 발생 변위가 작을 때 상대적으로 큰 오차를 나타냈으며, 이를 통해 진동계측과 같은 작은 동적변위의 계측에 한계가 존재한다고 판단된다.

In this study, a winch and load motion control system design method is introduced. Especially, the winch and load (moving cart) are connected with long wire rope which is extended to few kilometers long. Therefore, the rope length changes such that many dynamic parameter values are changed as well by winding and releasing the rope from the winch system. In this paper, the authors designed the control system by considering the real time parameter variation to occupy and keep good control performance continuously. The effectiveness of introduced method was evaluated by simulation results.

Liquid storage tank is one of the major infrastructures and generally used to store gases, drinking and utilizing water, dangerous fluids, fire water and so on. According to the recent reports and experiences, the tank structures are damaged in many earthquakes due to their low energy dissipating capacity. Therefore, many researchers have been tried to know the dynamic properties of the tanks including liquids. However, vary limited experimental studies are carried out using relatively small tank models. In this study, a series of shaking table tests are performed with maximum 2 m cubic rectangular liquid storage tanks made of steel to measure the natural frequency and estimate damping coefficient of impulsive and convective mode of the tanks. Especially, the damping values under different shapes and excitation methods are estimated by logarithmic decrement method and half power band-pass method and compared with current design code and standards such as ASCE 7, Eurocode 8 and NZS. Test results show that the impulsive mode damping is around 2% which is proposed by general standards and codes but the impulsive mode damping is 0.13% average that is slightly lower than the code recommendation.

Ryoo, Hye-Kyung. 2017. “Discourse Analysis of Microteaching: Dynamic Identities and Situational Frames”. The Sociolinguistic Journal of Korea 25(2), 165~196. The present paper is based on a discourse analysis of Microteaching speech events of Korean pre-service training students taking a teacher training course in college. The purpose of this study is to look closely into what really is going on in the discourse of microteaching events in terms of the participants' identity enactment and framing of situations. Fifteen pre-service training students' microteaching lessons were video-taped and transcribed to examine detailed discourse features. The results of the qualitative analysis of the discourse revealed frequent dynamic shifting and enactments of identities in momentary situational frames. The participants in the present study were able to act on diverse situational frames by orienting to locally-managed situated identities.

The paper presents a new short-term dynamic displacement estimation method based on an acceleration and a geophone sensor. The proposed method combines acceleration and velocity measurements through a real time data fusion algorithm based on Kalman filter. The proposed method can estimate the displacement of a structure without displacement sensors, which is typically difficult to be applied to earthquake or fire sites due to their requirement of a fixed rigid support. The proposed method double-integrates the acceleration measurement recursively, and corrects an accumulated integration error based on the velocity measurement, The performance of the proposed method was verified by a lab-scale test, in which displacement estimated by the proposed method are compared to a reference displacement measured by laser doppler vibrometer (LDV).

본 연구에서는 Karman이 제시한 풍방향 변동풍속 스펙트럼 및 Liang이 제시한 풍직각방향 변동풍하중 스펙트럼을 이용하여 풍방향 및 풍직각방향 풍하중을 생성하고, 생성된 풍하중을 적용하여 고정기초 및 면진기초 구조물의 동적 거동을 해석하여 풍하중이 작용하는 고정기초 구조물과 면진기초 구조물의 동적거동을 해석하여 면진기초에 의한 풍응답 증가에 대하여 비교분석하였다.

Safety flight training can be done, through the platform proposed in this paper. This paper designed a flight dynamic model and identified essential functions in order to enable pilots to simulate a training environment similar to the actual. It also design activity diagram, concept as well as class diagram. This paper presents the main features and direction of aircraft to be equipped in the future standard platforms. By design main class of flight dynamic and description. it will help developer to setup the standard platform for aircraft simulation.

오늘날 많은 음악 방송 프로그램이 성행하면서 보컬이 기성곡을 재해석하여 노래를 부르는 것 은 자신의 개성을 나타내기 위한 중요한 요소가 되었다. 하지만 재즈 보컬에게는 일반적인 연주 방식으로 재즈 스탠더드를 연주 소재로 삼을 때는 재해석을 통해 원곡에 대한 독창적인 해석을 선보인다. 그렇기에 재즈 보컬에게 넓은 음역, 올바른 발성법만큼 중요한 것이 자신만의 표현법 을 가지는 것이라 할 수 있다. 디 디 브릿지워터는 선율의 다이내믹을 표현하기 위해 연주 기법 을 차용한 폴, 예비음을 강조한 벤딩, 섬세한 다이내믹을 나타내는 점점 여리게 총 세 가지의 표현 기법을 중심으로 각 기법을 단독으로 사용하거나 조합하여 사용한다. 도출된 표현 기법와 조합의 특징에 대해 알아보고 분석곡을 중심으로 템포에 따라 활용된 세부 유형을 알아본다.

In this research, we have calculated characteristics of wave-piercing high-speed planing hull, by using a RANS solver and overset grid method, for comparing with experimental measurements of that and simulating with several appendages, since the computed results of commercial CFD code look reasonable for the prediction of the performances of planing hulls on calm water in planing conditions. As a result, it is confirmed that the dynamic instability phenomena in pitch and heave motions (porpoising) occurred after a certain FnV, and effectively suppressed using some of appendages, especially the 0.5L spray rail is suppressed to 24-55 % in the pitch motion and 33-55 % in the heave motion. In spray phenomenon, 1L hard chine suppress spray effectively and it is effective to set the angle of appendages to be less than 0° in order to suppress wave.

In development of high speed Rigid conductor line(R-bar) over 250km/h, it is important to develop the method to anticipate the mechanical stability of the R-bar and of the transition structure which connects the flexible Overhead Contact Line. To do this, firstly, the FE(Finite Element) model for a transition structure was established and the initial deformed configurations due to gravitational force is obtained by a static analysis and the pantograph was modeled by a simplified mass-spring-damper system and the contact behavior between conductor and pantograph was defined by the penality method. Secondly, FE analysis results were reviewed with the test results of contact force between conductor and pantograph at the low speed of train. Finally, using the established analysis method, the evolution of contact forces was performed for a newly designed high speed R-bar and for its transition structure.

관측된 지반진동은 지진원, 지각감쇠 및 지반의 증폭특성 등 3가지 주요 인자로 구성되어 있고 특히 지반증폭 특성은 지진원 및 감쇠특성을 평가할 때 필요하다. 또한 지진재해도를 분석하기 위해 지반의 증폭 특성에 정보가 내진 공학 뿐만 아니라 암반공학적 특성 분석에서 필수적이다. 지반의 증폭특성 분석을 위해 분석대상 관측소와 기준 관측소 지반진동의 수평/수직 비를 이용하는 방법을 적용하였다. 기존의 기준관측소의 수직성분 방법에 더하여 새로이 기준관 측소의 수평성분 방법을 새로이 시도하였다. 본 연구는 예당저수지 인근에 설치한 4개의 관측소에서 관측된 6개의 가 속도 지반진동을 이용하여 각 지반진동의 S파, Coda파 및 배경잡음 각각을 분석한 지반증폭 특성을 상호 비교하였다. 4개 관측소 공통적으로 S파와 Coda파를 이용한 결과는 상호 유사한 지반증폭 특성을 보였다. 다만 배경잡음은 다른 2 개 지진 에너지와 비교할 때 전혀 다른 지반증폭 특성을 보였고 이는 배경잡음의 발생 원인이 관측소 마다 서로 다르 기 때문으로 입증되었다. 4개 각각의 지진 관측소마다 저주파수 및 고주파수 증폭특성과 관측소 고유의 우월주파수가 서로 상이하여 관측소 고유의 증폭특성을 보여주었다. 또한 본 연구의 결과와 다른 방법의 결과와 비교하면 지반의 동 적특성 및 지반분류 연구에 많은 정보를 제시할 수 있다.

This study investigates dynamic characteristics of a 2MW wind turbine structure by long-term response monitoring with accelerometers, tiltmeter and strain gauges. The object wind turbine structure is located in Jeju Island, Korea. The natural frequency and damping ratio were evaluated by least-square frequency domain decomposition and random decrement technique using acceleration response data. As a result, it was found that natural frequencies with 1st, 2nd and 3rd modes, and blade passing frequencies with 1P, 2P and 3P were clearly showed from power spectral densities of acceleration reponses. Furthermore, 1st model frequencies were almost constant with increase in standard deviations of acceleration responses. Another notable observation was that when standard deviations of acceleration responses were small, damping ratios showed to diverge. However, when standard deviations of acceleration responses had large values, damping ratios were converged to about 0.5%.

In contemporary society, vibration and noise in the road nearby buildings have become social problems as vehicles operation has increased. Especially, in the case of the building used to art performance, available suitability of the building is tested by the indoor noise class. Therefore, the purpose of this paper is the measurement of the structure-borne noise of Seoul Art Center nearby Umyeonsan tunnel and analyzing the effects of countermeasure to it. To measure the effects of countermeasure, not only structure-borne noise is measured, but also the vibration is measured, before and after the construction of pavement using pad and porous asphalt. Consequently, the sound pressure level in art center 1st floor is reduced after mat pavement method, structure-borne noise that was high in 25Hz wide-band before pavement decreased regardless of experimental vehicle's velocity. Using porous asphalt pavement the noise was reduced about 3 dB(A).

Background: The multiple hop test is an active performance test that has been commonly used to assess individuals with functional ankle instability. Previous studies have suggested that insufficiency of dynamic postural stability and passive stability during dynamic activities can have an influence on performance in the multiple hop test. However, no study has investigated the effects of dynamic postural stability training and ankle bracing on multiple hop test performance in individuals with functional ankle instability. Objects: The purpose of this study was to compare the immediate effects of dynamic postural stability training versus ankle bracing in the performance of the multiple hop test for participants with functional ankle instability. Methods: Twenty-nine participants with functional ankle instability who scored below 24 in the Cumberland Ankle Instability Tool were selected. The participants were randomly divided into two groups: a dynamic postural stability training group (n1=14) and an ankle bracing control group (n2=15). The multiple hop tests were performed before and after applying each intervention. Dynamic postural stability training was performed using visual-feedback-based balance-training equipment; participants in this group were asked to perform a heel raise in a standing position while watching the centering of their forefoot pressure to prevent excessive ankle inversion. Ankle bracing was applied in the control group. Results: When comparing the pre- and post-intervention period for both groups, both methods significantly improved the results of the multiple hop test (p<.05). However, no significant differences were shown between the dynamic postural stability training and ankle bracing groups (p>.05). Conclusion: Both dynamic postural stability training and ankle bracing showed significant improvement (2.85 seconds and 2.05 seconds, respectively) in test performance. Further study is needed to determine the long-term effects of dynamic postural stability training and to determine whether insufficient dynamic postural stability is a causative factor for functional ankle instability.

Walking method based zero moment position algorithms that can guarantee the stability of the biped walking robot while walking, but it moves the legs for the stability of the walking in a way that is not related to energy conservation. Walking method using ZMP can cause low battery efficiency and load on leg joints. The walking method using the passive walking, which is a natural and efficient method of walking, can reduce the load on the joints of the robot by using the method without using the inertia that occurs when walking and reduced control elements and efficient use of battery. In this paper, a biped robot with an actuator based on the principle of passive dynamic walker mechanism is applied to a passive walking algorithm. In order to solve the problem of stabilization of the posture during walking, the posture was stabilized by using the swing motion of the arm. and the walking movement of the robot was observed using the AHRS sensor applied to the robot .It was confirmed that the posture can be stabilized based on measured values using AHRS.

In this study, we changed the existing S45C steel shafts applied to the drive shaft for power train of automotive to Al7003-T6 aluminum material. For this purpose, the optimal inner diameter of the aluminium shaft is established. And, analysis of the stresses and vibration characteristics of shafts were analyzed through finite element analysis. The final aluminum drive shaft was evaluated through the static torsional torque test and the frequency test. The Al7003-T6 aluminum drive shaft's weight is 67% comparing from 100% of shaft with existing steel, and with the performance of 3,276 N-m and 236 Hz, it satisfies requirements of the torsional torque of 3,000 N-m and vibration characteristic over 150 Hz required for drive shaft.

A fatigue analysis considering dynamic effects yields a more accurate fatigue life prediction than static fatigue analysis because it considers effects of inertia, flexibility and resonance that occur in the structure up to its natural frequency. However, the dynamic fatigue analysis of bogie frames of the rolling stock is not yet taken into account in the norm EN 13749. Therefore, in order to assure the safety of the rolling stocks, it is important to examine the fatigue analysis of that considering dynamic effects under applied load histories. Moreover, since the bogie frame consists of various welded joints, it is necessary to evaluate fatigue life of that considering welding properties as well as dynamic effects. In this study, under load histories converted from measured acceleration histories, static and dynamic fatigue analysis of the welded bogie frame are performed respectively.

PURPOSES : This paper presents a comparison study between dynamic and static analyses of falling weight deflectometer (FWD) testing, which is a test used for evaluating layered material stiffness. METHODS: In this study, a forward model, based on nonlinear subgrade models, was developed via finite element analysis using ABAQUS. The subgrade material coefficients from granular and fine-grained soils were used to represent strong and weak subgrade stiffnesses, respectively. Furthermore, the nonlinearity in the analysis of multi-load FWD deflection measured from intact PCC slab was investigated using the deflection data obtained in this study. This pavement has a 14-inch-thick PCC slab over finegrained soil. RESULTS: From case studies related to the nonlinearity of FWD analysis measured from intact PCC slab, a nonlinear subgrade modelbased comparison study between the static and dynamic analyses of nondestructive FWD tests was shown to be effectively performed; this was achieved by investigating the primary difference in pavement responses between the static and dynamic analyses as based on the nonlinearity of soil model as well as the multi-load FWD deflection. CONCLUSIONS : In conclusion, a comparison between dynamic and static FEM analyses was conducted, as based on the FEM analysis performed on various pavement structures, in order to investigate the significance of the differences in pavement responses between the static and dynamic analyses.