• Title, Summary, Keyword: DLT

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Stress Analysis and Shape Optimization of Dynamic Locking Tongue (DLT) Using FEM (FEM을 이용한 Dynamic Locking Tongue(DLT)의 강도 해석 및 형상 최적화)

  • Choi, Ji-Hun;Park, Tae-Won;Lee, Jin-Hee
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.6
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    • pp.699-705
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    • 2012
  • The role of a seat belt in a vehicle is to protect the driver from injury when a crash occurs. However when a large crash occurs, the driver slips forward and receives a strong impact. To prevent this situation, improvement of seat belts is essential. In this study, the new concept of a dynamic locking tongue (DLT) for seat belts is developed. The DLT device is used to reduce the impact to the driver's chest by tightening the webbing, so the driver is protected from severe injury in a large crash. First, a finite element model of the DLT device is created using SAMCEF and structural analysis is conducted with boundary conditions similar to those found in experiments. Then, the stress in the DLT device can be calculated. Second, the shape of the DLT device is optimized using the response surface analysis method in order to minimize the stress and weight. The validity of the optimization of the DLT device is verified using structural analysis.

Determination of Physical Camera Parameters from DLT Parameters

  • Jeong Soo;Lee Changno;Oh Jaehong
    • Proceedings of the KSRS Conference
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    • pp.233-236
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    • 2004
  • In this study, we analyzed the accuracy of the conversion from DLT parameters to physical camera parameters and optimized the use of DLT model for non-metric cameras in photogrammetric tasks. Using the simulated data, we computed two sets of physical camera parameters from DLT parameters and Bundle adjustment for various cases. Comparing two results based on the RMSE values of check points, we optimized the arrangement of GCPs for DLT.

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Determination of Physical Camera Parameters from DLT Parameters (직접선형변환 매개변수로부터 물리적 사진기 매개변수의 산정)

  • Jeong, Soo;Lee, Chang-No;Oh, Jae-Hong
    • Journal of Korean Society for Geospatial Information System
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    • v.13 no.2
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    • pp.39-43
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    • 2005
  • In this study, we analyzed the accuracy of the conversion from DLT parameters to physical camera parameters and optimized the use of DLT model for non-metric cameras in photogrammetric tasks. Using the simulated data, we computed two sets of physical camera parameters from DLT parameters and Bundle adjustment for various cases. Comparing two results based on the RMSE values of check points, we optimized the arrangement of GCPs for DLT.

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Evaluation for Geometric Calibration Accuracy of Zoom-lens CCD Camera (줌렌즈 CCD 카메라의 기하학적 검정 정확도 평가)

  • 유환희;정상용;김성삼
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.21 no.3
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    • pp.245-254
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    • 2003
  • Zoom lenses CCD(Charge Coupled Device) cameras have many desirable features but appear to be geometrically unstable and diffcult to calibrate. It is well blown that the zooming camera parameters change with zoom lens position. This paper presents a comparative study of two approaches, namely, DLT(Direct Linear Transformation) introduced by Abdel-Aziz and Karara and the model proposed by Tsai, to evaluate the camera parameters of zoom lenses CCD camera and 3D positioning accuracy. As a result, the accuracy for 3D positioning using Tsai and DLT model is similar in both methods when the set of GCPs and the object are arranged in the same space. However, Tsai model is more stable than DLT in the case that the object is apart from the set of GCPs. Also, the further study for the parameters optimization of conventional DLT is needed to improve accuracy for 3D positioning.

Comparison of displacement of polyvinyl chloride and silicone left-sided double-lumen tubes during lateral positioning

  • Kwon, Nyeong Keon;Jung, Sung Mee;Park, Sang-Jin;Han, Yonghee
    • Korean Journal of Anesthesiology
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    • v.72 no.1
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    • pp.32-38
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    • 2019
  • Background: Compared to an equivalent sized polyvinyl chloride (PVC) double-lumen tube (DLT), a silicone DLT has a shorter endobronchial segment. The aim of this study was to compare the incidence of clinically significant displacement of left-sided PVC and silicone DLTs after a positional change to a lateral position from a supine position and determine its effect on the need for DLT repositioning for successful lung separation in patients undergoing thoracic surgery. Methods: One hundred eight adult patients requiring one-lung ventilation were randomly divided into group P (PVC DLT, n = 54) and group S (Silicone DLT, n = 54). The position of the DLT was observed before and after lateral positioning to assess the effect of the position change. The incidence of clinically significant displacement (> 10 mm) of DLT was compared between the groups. Results: DLTs were clinically significantly displaced in group P (17/48, 35.4%) and group S (18/52, 34.6%) after lateral positioning (P = 0.933). A proximal displacement (31.3% [group P] and 25.0% [group S]) was more common than distal displacement (4.2% [group P] and 9.6% [group S]), with no significant intergroup difference (P = 0.494). After lateral positioning, critical malposition of DLT with bronchial herniation to the right main bronchus was 8.3% (group P) and 7.9% (group S, P = 0.906). Conclusions: Left-sided PVC and silicone DLTs produced comparable incidences of clinically significant displacement and, consequently, required similar rates of repositioning for successful lung separation after lateral positioning.

Vision-based hybrid 6-DOF displacement estimation for precast concrete member assembly

  • Choi, Suyoung;Myeong, Wancheol;Jeong, Yonghun;Myung, Hyun
    • Smart Structures and Systems
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    • v.20 no.4
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    • pp.397-413
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    • 2017
  • Precast concrete (PC) members are currently being employed for general construction or partial replacement to reduce construction period. As assembly work in PC construction requires connecting PC members accurately, measuring the 6-DOF (degree of freedom) relative displacement is essential. Multiple planar markers and camera-based displacement measurement systems can monitor the 6-DOF relative displacement of PC members. Conventional methods, such as direct linear transformation (DLT) for homography estimation, which are applied to calculate the 6-DOF relative displacement between the camera and marker, have several major problems. One of the problems is that when the marker is partially hidden, the DLT method cannot be applied to calculate the 6-DOF relative displacement. In addition, when the images of markers are blurred, error increases with the DLT method which is employed for its estimation. To solve these problems, a hybrid method, which combines the advantages of the DLT and MCL (Monte Carlo localization) methods, is proposed. The method evaluates the 6-DOF relative displacement more accurately compared to when either the DLT or MCL is used alone. Each subsystem captures an image of a marker and extracts its subpixel coordinates, and then the data are transferred to a main system via a wireless communication network. In the main system, the data from each subsystem are used for 3D visualization. Thereafter, the real-time movements of the PC members are displayed on a tablet PC. To prove the feasibility, the hybrid method is compared with the DLT method and MCL in real experiments.

Automated Geometric Correction based on Robust Estimation with Geostationary Weather Satellite Image (강인추정 기법에 기반한 정지궤도 기상위성영상의 자동 기하보정)

  • Lee, Tae-Yoon;Ahn, Myoung-Hwan;Oh, Hyun-Jong
    • Proceedings of the KSRS Conference
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    • pp.161-166
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    • 2007
  • Multi-functional Transport Satellite lR(MTSAT-lR)과 같은 정지궤도 기상위성의 지상 전처리 과정에는 영상위치보정(Image navigation and registration)이 포함된다. 영상위치보정은 위성 영상의 기하학적인 왜곡을 보정하는 과정이다. 랜드마크를 이용하는 영상위치보정 과정은 랜드마크 결정과 센서 모델 추정, 리샘플링(Resampling)의 세 가지 단계로 나눌 수 있다. MTSAT-1R의 High Resolution Image Data(HiRID)는 이미 영상위치보정이 수행되었지만, 기하학적인 오차가 남아있는 영상을 포함하기도 한다. 본 연구에서는 이런 기하학적인 오차를 제거하기 위해서 강인추정 기법에 기반한 기하보정을 수행하였다. 이태윤 등 (2005)은 강인추정 기법과 Direct Linear Transformation (DLT)에 기반한 오정합 판별 방법을 제안하였다. 이 판별 방법을 적용하여 추정된 DLT로 MTSAT-1R 영상의 기하보정을 수행한 결과에는 향상된 정확도로 기하보정 된 영상 뿐만 아니라 비교적 큰 오차를 포함하는 영상도 있었다. 이를 해결하기 위해서 본 연구에서는 강인추정 기법과 Affine 변환을 이용한 방법을 적용하였다. 본 연구에서는 기준 해안선에서 추출한 1,407개의 랜드마크와 8개의 MTSAT-1R 영상을 이용하였으며,강인추정 기법에 DLT를 적용한 방법과 Affine 변환을 적용한 방법으로 자동 기하보정을 수행하여 그 결과를 비교하였다. 또한 강인추정 기볍 중 RANSAC과 MSAC의 적용 결과를 비교하여 보았다. 그 결과,DLT로 기하보정 시,본 논문에서 제안된 방법이 강인추정 기법에 DLT를 적용한 방법 보다 더 좋은 성능을 보여주었다.

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Statistical analysis for RMSE of 3D space calibration using the DLT (DLT를 이용한 3차원 공간검증시 RMSE에 대한 통계학적 분석)

  • Lee, Hyun-Seob;Kim, Ky-Hyeung
    • Korean Journal of Sport Biomechanics
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    • v.13 no.1
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    • pp.1-12
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    • 2003
  • The purpose of this study was to design the method of 3D space calibration to reduce RMSE by statistical analysis when using the DLT algorithm and control frame. Control frame for 3D space calibration was consist of $1{\times}3{\times}2m$ and 162 contort points adhere to it. For calculate of 3D coordination used two methods about 2D coordination on image frame, 2D coordinate on each image frame and mean coordination. The methods of statistical analysis used one-way ANOVA and T-test. Significant level was ${\alpha}=.05$. The compose of methods for reduce RMSE were as follow. 1. Use the control frame composed of 24-44 control points arranged equally. 2. When photographing, locate control frame to center of image plane(image frame) o. use the lens of a few distortion. 3. When calculate of 3D coordination, use mean of 2D coordinate obtainable from all image frames.

Formulation and Pharmacokinetic Evaluation of Sustained Release Preparation Containing Clebopride Malate (말산클레보프리드 서방성 제제의 제조 및 약물동태학적 평가)

  • Ryou, Hae-Won;Lee, Joo-Han;Chi, Yong-Ha;Hahn, Yang-Hee;Tan, Hyun-Kwang;Lee, Kyu-Heung;Kim, Sang-Lin;Jeon, Seung-Yoon;Choi, Young-Wook
    • Journal of Pharmaceutical Investigation
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    • v.30 no.3
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    • pp.179-189
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    • 2000
  • Clebopride malate(Cm) is a new benzamide drug which has a potent central antidopaminergic activity possessing antiemetic and anxiolytic properties. A purpose of this study was to assess the feasibility of formulating sustained release preparation by dispersing a drug in hydrophilic polymeric matrices and double layered tablets(DLT), using HPMC, carbopol, PEO, PVP/VA and other polymers as a rate controlling barrier. The matrix and DLT showed optimum dissolution pattern up to 8 hours and the contents of polymer were optimized at 30% level in this preparation. After an oral administration in beagle dog, Cm concentration was determined by use of GC-ECD and pharmacokinetic parameters were calculated by Vallner's method. The AUC of DLT showed similar results and the duration of action was increased 55% compared to that of regular release dosage form. The calculated absorption rate effectiveness(ARE) and controlled release effectiveness(CRE) for DLT increased 50% compared to that of matrix, the overall effectiveness(E) of this product appears to be about 70%. in vivo effectiveness test, DLT showed significant differences from control on antiemetic action of Cm. In consequence, it was possible to conclude that double layered tablet might be a good candidate for the sustained release dosage forms.

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Hybrid Type Structure Design and DLT-Replacement Circuit of the High-Speed Frequency Synthesizer (고속 스위칭 동작의 주파수 합성기를 위한 하이브리드형 구조 설계와 DLT 대체 회로 연구)

  • Lee Hun-Hee;Heo Keun-Jae;Jung Rag-Gyu;Ryu Heung-Gyoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.12
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    • pp.1161-1167
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    • 2004
  • The conventional PLL(phase locked loop) frequency synthesizer takes a long switching time because of the inherent closed-loop structure. The digital hybrid PLL(DH-PLL) which includes the open-loop structure into the conventional PLL synthesizer has been studied to overcome this demerit. It operates in high speed, but the hardware complexity and power consumption are the serious problem because the DLT(digital look-up table) is usually implemented by the ROM which contains the transfer characteristic of VCO(voltage controlled oscillator). This paper proposes a new DH-PLL using a very simple DLT-replacement digital logic instead of the complex ROM-type DLT. Also, a timing synchronization circuit for the very small over-shoot and shorter settling time is designed for the ultra fast switching speed at every frequency synthesis. The hardware complexity gets decreased to about $28\%,$ as compared with the conventional DH-PLL. The high speed switching characteristic of the frequency synthesis process can be verified by the computer simulation and the circuit implementation.