• 대한임베디드공학회논문지
• /
• 제13권1호
• /
• pp.17-24
• /
• 2018

Military camera equipment has a problem that observability is inferior due to various shaking factors. In this paper, we propose an image stabilization algorithm considering performance and execution time to solve this problem and implemented it in Zynq SoC. We stabilized both the simple shaking in the fixed observation position and the sudden shaking in the moving observation position. The feature of the input image is extracted by the Sobel edge algorithm, the subblock with the large edge data is selected, and the motion vector, which is the compensation reference, is calculated through template matching using the 3-step search algorithm of the region of interest. In addition, the proposed algorithm can distinguish the shaking caused by the simple shaking and the movement by using the Kalman filter, and the stabilized image can be obtained by minimizing the loss of image information. To demonstrate the effectiveness of the proposed algorithm, experiments on various images were performed. In comparison, PSNR is improved in the range of 2.6725~3.1629 (dB) and image loss is reduced from 41% to 15%. On the other hand, we implemented the hardware-software integrated design using HLS of Xilinx SDSoC tool and confirmed that it operates at 32 fps on the Zynq board, and realized SoC that operates with real-time processing.

• 한국식품과학회지
• /
• 제24권4호
• /
• pp.353-360
• /
• 1992

유통과정 중 발생가능한 요구르트의 품질변화를 알아보기 위하여 저장온도 (10 & $20^{\circ}C$)와 교반조건(100 & 200 rpm에서 각각 30분간 교반)을 달리한 요구르트의 저장기간에 따른 미생물학적, 물리화학적 및 관능적 특성을 조사하였다. 저장온도가 높고 저장기간이 길어짐에 따라 적정산도와 TCA soluble nitrogen이 증가되었고 pH, 유당 및 유산균 수는 감소되는 경향을 보였으나 교반조건에 따른 변화는 나타나지 않았다. pH, 적정산도 및 유산균 수는 $10^{\circ}C$ 저장시 15일 동안 변화가 없었으나 $20^{\circ}C$ 저장시는 큰 폭으로 감소되었다. 관능검사 결과 저장온도가 높고 저장기간이 길어짐에 따라 신맛은 증가하고 단맛은 감소되었으며 $10^{\circ}C$ 저장시는 15일까지, $20^{\circ}C$ 저장시는 3일까지 저장초기와 차이가 없었다. 이취의 발생은 $10^{\circ}C$ 저장시는 200 rpm으로 교반한 군에서 12일째부터, $20^{\circ}C$ 저장시는 교반조건에 상관없이 6일부터 이취가 발생되어 제품으로서의 가치를 상실하였다. 관능검사에 의한 견고성 평가결과는 consistometer로 측정한 결과와 잘 일치되었는데 200 rpm으로 교반한 경우는 교반하지 않은 군보다 견고성이 유의적으로 낮게 나타났으며, 저장온도가 높고 저장기간이 길어짐에 따라 증가되는 양상을 나타내었다. 이와 같은 결과로 유통과정 중 우수한 품질을 유지하기 위해서는 냉장저장 및 운반시의 충격을 가능한 피하는 것이 바람직하다고 본다.

• 한국지진공학회논문집
• /
• 제22권4호
• /
• pp.253-259
• /
• 2018

Structure behaviors resulting from an earthquake are experimentally simulated mainly through a shaking table test. As for large-scale structures, however, size effects over a miniature may make it difficult to assess actual behaviors properly. To address this problem, research on the hybrid simulation is being conducted actively. This method is to implement numerical analysis on framework members that affect the general behavior of the structure dominantly through an actual scale experiment and on the rest parts by applying the substructuring technique. However, existing studies on hybrid simulation focus mainly on Slow experimental methods, which are disadvantageous in that it is unable to assess behaviors close to the actual level if material properties change depending on the speed or the influence of inertial force is significant. The present study aims to establish a Real-time hybrid simulation system capable of excitation based on the actual time history and to verify its performance and applicability. The hybrid simulation system built up in this study utilizes the ATS Compensator system, CR integrator, etc. in order to make the target displacement the same with the measured displacement on the basis of MATLAB/Simulink. The target structure was a 2-span bridge and an RC pier to support it was produced as an experimental model in order for the shaking table test and Slow and Real-time hybrid simulations. Behaviors that result from the earthquake of El Centro were examined, and the results were analyzed comparatively. In comparison with the results of the shaking table test, the Real-time hybrid simulation produced more similar maximum displacement and vibration behaviors than the Slow hybrid simulation. Hence, it is thought that the Real-time hybrid simulation proposed in this study can be utilized usefully in seismic capacity assessment of structural systems such as RC pier that are highly non-linear and time-dependent.

• Earthquakes and Structures
• /
• 제12권1호
• /
• pp.67-77
• /
• 2017

In this paper, it is aimed to present a comparative study about the structural behavior of tall buildings consisting of different type of materials such as concrete, steel or timber using finite element analyses and experimental measurements on shaking table. For this purpose, two 1/60 scaled 28 and 30-stories wooden building models with $40{\times}40cm$ and $35{\times}35cm$ ground/floor area and 1.45 m-1.55 m total height are built in laboratory condition. Considering the frequency range, mode shapes, maximum displacements and relative story drifts for structural models as well as acceleration, displacement and weight limits for shaking table, to obtain the typical building response as soon as possible, balsa is selected as a material property, and additional masses are bonded to some floors. Finite element models of the building models are constituted in SAP2000 program. According to the main purposes of earthquake resistant design, three different earthquake records are used to simulate the weak, medium and strong ground motions. The displacement and acceleration time-histories are obtained for all earthquake records at the top of building models. To validate the numerical results, shaking table tests are performed. The selected earthquake records are applied to first mode (lateral) direction, and the responses are recorded by sensitive accelerometers. Comparisons between the numerical and experimental results show that shaking table tests are enough to identify the structural response of wooden buildings. Considering 20%, 10% and 5% damping rations, differences are obtained within the range 4.03-26.16%, 3.91-65.51% and 6.31-66.49% for acceleration, velocity and displacements in Model-1, respectively. Also, these differences are obtained as 0.49-31.15%, 6.03-6.66% and 16.97-66.41% for Model-2, respectively. It is thought that these differences are caused by anisotropic structural characteristic of the material due to changes in directions parallel and perpendicular to fibers, and should be minimized using the model updating procedure.

• 한국인터넷방송통신학회논문지
• /
• 제14권3호
• /
• pp.155-162
• /
• 2014

본 논문에서는 이동차량 양상 안정화를 위한 효율적인 흔들림 보정 기법을 제안한다. 제안된 흔들림 보정 기법은 입력으로 받은 영상 이미지 프레임의 색상 분리를 통한 변환 및 분리정보에 대한 누적 히스토그램을 계산하였고, 흔들리는 차량용 영상 이미지를 보정한 결과에서 색상 정보를 맞추기 위해 히스토그램 매칭을 하였다. 본 논문에서 제안된 흔들림 보정 기법은 기존 차량 영상 안정화 기술과 비교하였을 때, 휘도 및 컬러 레벨의 비교를 통해 노이즈가 가장 적고 영상의 자연스러움이 더 뛰어난 복원 결과를 얻을 수 있었다. 또한, 흔들림 보정 기법은 메모리를 사용하지 않고 실시간으로 처리를 통해 다른 방법과 비교하여 효율성을 입증하였다.

• 한국멀티미디어학회논문지
• /
• 제20권8호
• /
• pp.1236-1247
• /
• 2017

In this paper, we propose a method for evaluating the uncomfortable shaking in the video. When you shoot a video using a handheld device, such as a smartphone, most of the video contains unwanted shake. Most of these fluctuations are caused by hand tremors that occurred during shooting, and many methods for correcting them automatically have been proposed. It is necessary to evaluate the shake correction performance in order to compare the proposed shake correction methods. However, since there is no standardized performance evaluation method, a correction performance evaluation method is proposed for each shake correction method. Therefore, it is difficult to make objective comparison of shake correction method. In this paper, we propose a method for objectively evaluating video shake. Automatically analyze the video to find out how much tremors are included in the video and how much the tremors are concentrated at a specific time. In order to measure the shaking index, we proposed jitter modeling. We applied the algorithm implemented by Optical Flow to the real video to automatically measure shaking frequency. Finally, we analyzed how the shaking indices appeared after applying three different image stabilization methods to nine sample videos.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1992년도 가을 학술발표회 논문집
• /
• pp.140-154
• /
• 1992

The objective of the research stated here was aimed at providing the information needed to establish the Korean Seismic Design Code Recommendations and Guides for precast concrete (P.C) large panel apartment buildings. This was accomplished by investigation and analysis of the response of P.C large panel structures subjected to shaking table excitation simulating earthquake ground motion. one of the test specimens used was 1/3-scaled 3-story box P.C model provided by Sam-Hwan Camus Corporation. The 4m $\times$4m shaking table was used to simulate the earthquake ground motion. the employed input accelerogram was the one recorded as Taft N21E component and the peak ground acceleration(PGA) was scaled depending on the desired level of seismic severity and the time according to dynamic similitude rule. Based on results obtained from shaking table test of this P.C model, the following conclusions were drawn . (1) As far as test specimen is concerned, the seismic safety factors turns out to be 7~8. (2)P.C model has damping ratio of about8% which is twice larger than in-situ R.C. structure. And (3)this model has global displacement ductility ratio of 2~3 through the energy dissipation by opening and sliding of joints.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2010년도 추계 학술발표회
• /
• pp.173-183
• /
• 2010

Numerical analysis using a three dimensional finite element program(ABAQUS) is a powerful method which can evaluate the soil-pile-structure interaction under the dynamic loading and reduce the computation time significantly, but has not be widely used because modeling a soil-pile system and setting the parameter for the entire model are difficult and a three dimensional finite element program is not user friendly. However, a three dimensional finite element program is expected to be widely used because of advance in research of modeling technique and development of the modeling and visualization. In this study, ABAQUS is used to simulate the 1g shaking table model pile test, and the numerical results are compared with the 1g shaking table test results. The application about the soil stiffness and boundary condition change is estimated and then parametric study for various input acceleration amplitudes, various input frequencies, and various surcharge is carried out.

• 한국철도학회논문집
• /
• 제13권4호
• /
• pp.440-446
• /
• 2010

본 논문은 적층고무받침을 이용하여 지진으로부터 교량의 손상피해를 줄이기 위한 연구이다. 적층고무 받침은 지진 발생시 변위를 증가시키고, 주기를 길게하여 하중을 전환시킨다. 적층고무받침과 같은 면진장치에 몇 가지 지진파를 가진하여 진동대 실험을 하였다. 이 실험에서는 가속도계와 하중계, 변위계를 설치하여 상판의 가속도 및 전단력 등을 측정하였다. 더구나 적층고무받침을 설치한 경우와 지진격리장치를 설치하지 않은 경우로 구분하여 진동대 실험하여 그 성능을 비교 평가하였다. 실험결과 상판의 가속도 및 전단력은 적층고무받침을 사용할 경우 응답이 감소하였다.

• Advances in pediatric surgery
• /
• 제17권1호
• /
• pp.51-57
• /
• 2011

Use of laparoscopic appendectomy (LA) for perforated appendicitis (PA) in children remains controversial because of the development of postoperative intra-abdominal abscess formation. We developed the irrigation method for the prevention of abscess formation after LA performed for PA in children with severe panperitonitis. We called it 'the shaking irrigation'. The object of this study was to analyze the efficacy of this irrigation method. All cases of PA with severe panperitonitis in children that underwent LA with massive shaking irrigation and drainage between June 2003 and December 2007 were studied retrospectively. We included only PA with panperitonitis and large amounts of purulent ascites throughout the abdomen as well as an inflamed small bowel with ileus. Thirty-four children were involved in this study. The mean patient age was eight years. The mean amount of irrigation fluid was 8.2 L (range: 4-15 L), The mean operative time was 89.5 min. The mean length of the hospital stay was 5.1 days. There were no postoperative intra-abdominal abscesses. There was no conversion to open surgery. In conclusion, Use of LA in PA with severe panperitonitis in children is safe and effective. Massive shaking irrigation and abdominal drainage appears to prevent intra-abdominal abscesses after LA for PA with panperitonitis.