The vibration control device such as the damper can be used to reinforce the seismic performance of structures. The damper is activated by the deformation of structures during earthquake; however, the deformation of structures is extremely small, causing difficulty in using the damper. Therefore, there is a need for a method capable of amplifying small deformities and transmitting them to the damper. The purpose of this paper is to develop and evaluate a displacement amplification seismic system using cable-pulley. The appropriate cable was selected through a cable tensile performance test and the results of the frame experiment were compared with theoretical displacement amplification ratio values. As a result, it may be said that the proposed system using cable-pulley is useful for displacement amplification.

Lightly reinforced concrete (RC) moment frames may suffer significant damage during large earthquake events. Most buildings with RC moment frames were designed without considering seismic loads. The load-displacement response of gravity load designed frames could be altered by masonry infill walls. The objective of this study is to investigate the load-displacement response of gravity load designed frames with masonry infill walls. For this purpose, three-story gravity load designed frames with masonry infill walls were considered. The masonry infilled RC frames demonstrated larger lateral strength and stiffness than bare RC frames, whereas their drift capacity was less than that of bare frames. A specimen with a partial-height infill wall showed the least drift capacity and energy dissipation capacity. This specimen failed in shear, whereas other specimens experienced a relatively ductile failure mode (flexure-shear failure).

The tendency to use a probabilistic design method rather than a deterministic design method for the design of nuclear power plants (NPPs) will increase because their safety should be considered and strictly controlled in relation to various causes of damage. The distance between a seismically isolated NPP structure and a moat wall is called the clearance to stop. The clearance to stop is obtained from the 90th percentile displacement response of a seismically isolated NPP subject to a beyond design basis earthquake (BDBE) in the probabilistic design method. The purpose of this study is to analyze the effects of heating and buckling effects on the 90th percentile displacement response of a lead-rubber bearing (LRB) subject to a BDBE. The analysis results show that considering the heating and buckling effects to estimate the clearance to stop is conservative in the evaluation of the 90th percentile displacement response. If these two effects are not taken into account in the calculation of the clearance to stop, the underestimation of the clearance to stop causes unexpected damage because of an increase in the collision probability between the moat wall and the seismically isolated NPP.

Objectives of this study were to identify the hotspot for displacement of the on-line water quality sensors, in order to detect illicit discharge of untreated wastewater. A total of twenty-six water quality parameters were measured in sewer networks of the industrial complex located in Daejeon city as a test-bed site of this study. For the water qualities measured on a daily basis by 2-hour interval, the self-organizing maps(SOMs), one of the artificial neural networks(ANNs), were applied to classify the catchments to the clusters in accordance with patterns of water qualities discharged, and to determine the hotspot for priority sensor allocation in the study. The results revealed that the catchments were classified into four clusters in terms of extent of water qualities, in which the grouping were validated by the Euclidean distance and Davies-Bouldin index. Of the on-line sensors, total organic carbon(TOC) sensor, selected to be suitable for organic pollutants monitoring, would be effective to be allocated in D and a part of E catchments. Pb sensor, of heavy metals, would be suitable to be displaced in A and a part of B catchments.

가속도로부터 변위를 계산 방법 중 상대적으로 사용이 간단한 변위재구성기법이 Lee et al.(2010)과 Hong et al.(2010)에 의해 제안되었다. 목표주파수는 변위재구성기법을 사용할 때 사용자가 결정해야 할 중요한 변수 중 하나로 이것을 결정하기 위해선 주파수영역 분석에 대한 경험이 필요하다. 이 논문은 지진하중을 받는 사장교에 한정된 변위재구성기법의 목표주파수 결정 방법을 제시한다. 사장교가 지진에 의해 가진될 경우 목표주파수는 유효한 모드의 고유주파수 중 가장 낮은 주파수로 결정된다. 여기서 유효한 모드라 함은 가속도의 자유도에 유의미한 영향을 주는 모드형상을 가진 모드를 의미한다. 제안된 목표주파수 결정방법의 타당성을 검증하기 위해 포항지진 발생 당시 측정된 3개 실 교량의 주경간 중앙에서 측정된 가속도와 변위 시간이력을 분석했다. 또한 제안된 방법을 포항지진 발생 당시 측정된 실교량의 주탑 상단 가속도에 적용해 계산된 변위를 분석했다.

본 연구에서는 수집영상의 매 프레임 MPC(mm/pixel coefficient) 업데이팅을 통해 축 방향과 상관없이 왜곡영상에 따른 변위를 보정하는 기법에 관해 다루고자 한다. 영상의 강제적 왜곡을 위해 다양한 촬영 각도를 설정하여 실험을 진행하였으며, 캠코더의 설치 위치를 통해 0°~55°까지 5° 단위로 12가지 촬영 각도를 조정해가며 영상을 수집·분석하였다. 본 실험에 앞서 영상기반 변위계측의 유효성 평가를 위한 예비실험을 수행하였으며, GPS 및 가속도계와 계측결과를 비교해보았을 때, 영상기반 변위계측 시스템은 충분한 유효성을 갖는다고 판단된다. 촬영 각도 별로 수집된 영상을 분석하여 구조물의 최대 진폭 및 추정 진동수를 검출하였으며, 검출결과 비교를 통해 촬영 각도에 의한 영향을 판단하고자 하였다. 또한 계측된 자유 진동으로부터 감쇠비를 추정하여 추가적인 비교를 수행 하였다. 분석 결과 최대 진폭 기준 0.325mm, 오차율 기준 5.72%의 미소한 오차를 나타냈다. 진동수 추정에서도 촬영 각도 50°를 제외 하고 전체적으로 1% 미만의 오차율을 보이며 매우 유사한 추정 결과를 나타냈으며, 촬영 각도가 변화에 따른 감쇠비는 최소 1.025% 에서 최대 1.189%의 추정결과를 보이며 촬영 각도와 상관없이 전체적으로 유사한 감쇠비를 나타냈다.

Now that problems with force-based seismic design have been clearly identified, design is inclined toward displacement-based methods. One such widely used method is Direct-Displacement-Based Design (DDBD). Yet, one of the shortcomings of DDBD is considering higher-mode amplification of story shear, moments, and displacements using equations obtained from limited parametric studies of regular planar frames. In this paper, a different approach to account for higher-mode effects is proposed. This approach determines the lateral secant stiffness of the building frames that fulfill the allowable inter-story drift without exceeding the desired story displacements. Using the stiffness, an elastic response spectrum analysis is carried out to determine elastic higher-mode force effects. These force effects are then combined with DDBD-obtained first-mode force effects using the appropriate modal superposition method so that design can be performed. The proposed design procedure is verified using Nonlinear Time History Analysis (NTHA) of twelve planar frames in four categories accounting for mass and stiffness irregularity along the height. In general, the NTHA response outputs compared well with the allowable limits of the performance objective. Thus, it fulfills the aim of minimizing the use of NTHA for planar frame buildings, thereby saving computational resources and effort.

In this study, the structural analysis was performed by using Solidworks program to investigate the stress and displacement characteristics of upper desk and table arm depending on the types and positions of load applied to the height-adjustable table(Cases 1, 2, 3, 4). The simulation was used to model the table and create the mesh for computational analysis. The height-adjustable table consists of three parts, upper desk, table arm and support body. Case 3 with the side concentrated load showed the maximum stress and maximum displacement at table arm and upper desk. From the stress and displacement characteristics of the upper desk and table arm, the stresses at the bending part of table arm and the deflection at the front part of upper desk were the greatest.

본 논문에서는 이단계 칼만필터를 활용한 구조물의 3 자유도 동적변위 계측 시스템을 소개한다. 개발 시스템은 센서 모듈, 베이스 모듈, 컴퓨테이션 모듈로 구성되어 있다. 센서 모듈은 100Hz 샘플주파수의 고정밀 가속도를 계측하는 포스피드백 가 속도계와 10Hz의 샘플주파수의 저정밀도의 속도, 변위를 계측하는 저가의 RTK-GNSS로 구성되어 있다. 계측된 데이터는 LAN 케이블을 통하여 컴퓨테이션 모듈로 전송되고, 컴퓨테이션 모듈에서 이단계 칼만필터를 활용하여 100Hz 샘플주파수의 고정밀 변위를 실시간으로 산정한다. 개발 시스템의 변위 계측 정밀도를 검증하기 위해 미국, 캘리포니아에 위치한 San Francisco-Oaklmand Bay bridge 에서 현장 실험을 수행하였으며, 실험 결과 1.68mm RMS 오차를 보임을 확인하였다.

Asphalt pavement overlay method is one of widely chosen construction methods for remodelling existing aged concrete pavement layer. However, in this case reflective cracking is a challenging issue due to movement of transverse joints: built in existing concrete pavement layer with constant interval length. In this paper, collecting field data: collection of displacement and temperature data on existing concrete pavement layer for further complicated pavement performance analysis, was performed. To fulfil this objective, various types of thermometer were embedded into concrete layer with different depth level. Then, movement of existing concrete layer was measured numerically. Each Displacement Measuring Gauge (DMG) along with thermometer was embedded with depth of 3cm and 15cm, respectively. Additional thermometers were embedded at the middle depth of overlaid asphalt pavement layer for further extensive analysis and data collection. Total four testing sites were considered based on different asphalt mixture type and construction method. The 1st site was constructed with conventional construction approach, the 2nd site was constructed with a new pavement equipment contains simultaneous tack-coating function, the 3rd site was similar to 1st site but Guss-asphalt was constructed as a binder course, and in 4th site Noise-Reduction Porous Asphalt (NRPA) was constructed as a surface course and regular Dense Grade Asphalt (DGA) was constructed as a binder course. A field asphalt pavement layer sample coring works: along with basic material property tests, were also performed to acquire not only overlaid asphalt but also existing concrete pavement materials. This gauge measuring work in this study is an initial step therefore, long-term movement data of each pavement layer was not able to be collected, unfortunately. However through collecting and analysing initial data on each test site, two crucial findings were acquired. First, in all four tested site highest temperature variations were observed at the upper asphalt pavement layer and the variation trends decreased with increase of pavement depth (in case of concrete pavement layer, temperature and movement variations also decreased with increase of pavement depth). Secondly, when Guss-asphalt was applied as a binder course temperature variations of existing concrete pavement layer was crucially smaller than those of other comparison cases. These current findings and collected data set can provide successful input information for further pavement structure analysis such as 2D (and/or 3D) Finite Element Method (FEM) analysis as a future study.

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.

Smart phones are currently the most popular electronic devices with high volume production activities driven by high demand and requirements for rapid turnaround time. The changes of displacement were analyzed according to a variable of the gate size and runner system. The radial type and gate with large size were shown that better results in displacement. While the design and production of lenses, the key component of a camera, still need to be improved, the current technology has run into its limit with regard to trends in size and weight reduction. In this study, an injection molding analysis was performed on plastic lenses that are widely employed for smart phone cameras. Specifically, the displacement of lenses at the time of injection molding was studied by varying the gate size and runner system.

분리막의 기공 크기 및 분포도를 분석하기 위한 다양한 측정법이 있지만 10-50 nm 범위의 한외여과막 기공크기 를 정확하게 측정하기가 까다롭다. 따라서 gas-liquid displacement porometer (GLDP)와 liquid-liquid displacement porometer (LLDP) 기공 특성 측정법 두 가지를 이용하여, 10-100 nm의 기공크기를 갖는 세 종류의 세라믹 분리막(K-100, A-100, A-20) 의 기공 크기 및 분포도를 비교 분석하였다. GLDP는 한외여과막의 최대 기공크기를 측정하는데 적합한 분석법으로 확인되 었고, LLDP로 측정된 평균 기공크기가 분리막의 분리 성능 결과와 더 연계되어 있었다. 또한 LLDP는 10-50 nm 범위의 기 공크기를 측정하는데 적합한 기공 분석법으로 확인되었으나, GLDP 보다 낮은 정밀도와 높은 민감도를 나타내었다. 다양한 기공 특성 분석법 가운데, 최근 상용화된 LLDP 기술은 종래의 측정법으로 알지 못했던 유용한 결과들을 제공할 수 있을 것 으로 기대된다.

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).

Building hardware joints are welded in most cases, which have risks of fire and explosion. Besides, the secondary damage of the destruction of the welded parts can be caused by the horizontal displacement of the structure due to earthquake or wind load. This paper compared the horizontal displacement following abilities of welded building hardware and non-welded building hardware. To do this, We conducted actual formation shake table test, and checked on the horizontal displacement following ability of structure by comparing their responses to earthquake load. We made the 2m-high framework to examine the responses of the actually constructed building hardwares, and analyzed the displacement responses of the welded-typed, non-welded-typed, and cruciform bracket building hardwares. We conducted the test by increasing acceleration rate until displacement reached 40mm corresponding to allowable relative story displacement II. The result of the test showed that the building hardware using welding work made cracking and breakage on welded connections of welded building hardware, but non-welded building hardware with no use of welding work and cruciform bracket building hardware make no problem, and that non-welded building hardware is superior to that of the welded building hardware in the horizontal displacement following ability due to earthquake or wind load.