• KIPS Transactions on Software and Data Engineering
• /
• v.5 no.1
• /
• pp.35-42
• /
• 2016

The core of the machine vision that is frequently used at the pre/post-production stages is a marker alignment technology. In this paper, a method to detect the angle and position of a product at high speed by use of a unique pattern present in the marker stamped on the product, and calibrate them is proposed. In the proposed method, to determine the angle and position of a marker, the candidates of the marker are extracted by using a variation of the integral histogram, and then clustering is applied to reduce the candidates. The experimental results revealed about 5s 719ms improvement in processing time and better precision in detecting the rotation angle of a product.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.12
• /
• pp.1563-1568
• /
• 2012

Printed electronics is a technology used for forming electronic circuits or devices, and it is used in the manufacture of many products such as RFID tags, solar cells, and flexible display panels with a much lower cost than in the case of semiconductor process technology. Web-guide-type printing such as roll-to-roll printing is a method used to produce printed electronic devices in a large volume. To commercialize such products, highly precise alignment between printed layers is required. In this study, a highly precise alignment system is proposed, and some experimental results are compared with those obtained using a laser surface vibrometer to illustrate the reliability of the proposed system. The robustness of the proposed system to web deformation is also considered experimentally.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.13 no.2
• /
• pp.127-134
• /
• 2005

This paper introduces a newly developed high speed material testing apparatus for tensile tests at the strain rate up to 500/sec. The tensile properties of sheet metals are indispensable for the accurate crashworthiness analysis of auto-bodies since the local strain rate reaches to 500/sec in the car crash. An appropriate experimental method has to be developed to acquire the tensile properties at the intermediate strain rate ranged from 0.003/sec to 200/sec. Tensile tests of various different steel sheets for an auto-body were perform ed to obtain the dynamic properties with respect to the strain rate. The dimensions of specimens that can provide the reasonable results were determined by the finite element analysis. A special jig fixture of a load cell is designed to reduce the load ringing phenomenon induced by unstable stress propagation at the high strain rate. Stress-strain curves were acquired for each steel sheet from the dynamic tensile test and utilized to obtain the relationship of the stress to the strain rate.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.39 no.2
• /
• pp.11-21
• /
• 2002

Although the matching Pursuit is effective for video coding at low bit rate, it has a Problem since it needs much more calculation than the conventional block-based video coding method. The proposed fast matching pursuit method reduces inner product calculation that takes the most part of entire calculation by utilizing the symmetry of the absolute values of the one-dimensional Gator dictionary bases, the modified dictionary which allows faster matching without causing image quality degradation, and a Property of the two-dimensional Gabor dictionary that can be grouped in advance to four classes according to its frequency characteristics. Proposed method needs only about 1/8 of multiplications compared to the well-known separability-based fast method proposed by Neff.

• 한국HCI학회:학술대회논문집
• /
• 2008.02a
• /
• pp.39-44
• /
• 2008

This paper proposes a real-time geometric correction system based on a projector to project digital images onto deformable surface. Markers use to trace lots of corresponding points would spoil the projected image when the projector projects a digital image onto the surface because they leave marks on the surface. In addition, it is difficult to build a real-time geometric correction system since bottlenecks occur through the process of the geometric correction for projecting images. In this paper, we use invisible infrared markers and a vertex shader of GPU using Cg TookKit of NVIDIA in order to eliminate disadvantage and bottlenecks in the process of markers recognition so that it is possible to project natural correction images in real-time. As a result, this system overlays an interactive virtual texture onto the real paper by using the geometric transformation. Therefore, it is possible to develop variation of AR(Augmented Reality) based on digital contents systems.

• Journal of Ocean Engineering and Technology
• /
• v.29 no.3
• /
• pp.241-248
• /
• 2015

A subsea pipeline for oil/gas transportation or gas injection is subjected to extreme variations in internal pressure and temperature, which can involve a strain rate effect on the pipeline material. This paper describes the flow stress characteristics of a pipeline material called API 5L X52N PSL2, using and experimental approach. High-speed tensile tests were carried out for two metal samples taken from the base and weld parts. The target temperature was 100℃, but two other temperature levels of –20℃and 0℃ were taken into account. Three strain rates were also considered for each temperature level: quasi static, 1/s, and 10/s. Flow stress data were proposed for each temperature level according to these strain rates. The dynamic hardening behaviors of the base and weld metals appeared to be nonlinear on the log-scale strain rate axis. A very high material constant value was required for the Cowper-Symonds constitutive equation to support the experimental results.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.8
• /
• pp.1129-1136
• /
• 2009

The paper presents the performance characteristics for a cooling system using EEV. The water cooler was used to reduce thermal deformation and contraction due to high speed of machine tools and the EEV was used for capacity control for water cooler. The apparatus was designed for hot-gas bypass system which a hot-gas can flows from outlet of compressor to the inlet of evaporator. This experiment is the intermediary study for precise temperature control through PID control. The results show that the evaporator pressure increased and refrigeration capacity decreased as the EEV opening step of hot-gas bypass increased. These results can be used as basic data for the design of effective water cooler.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.8 no.3
• /
• pp.349-355
• /
• 2020

The purpose of this study is to investigate the effects of types and amounts of fibers on the compressive strength and tensile behavior high strength fiber-reinforced composites under a static load and impact resistance properties of composites under a high-velocity projectile impact load. Three kinds of mixtures were designed and specimens were manufactured. compressive strength, uniaxial tension, and high velocity projectile impact load tests were performed. Test results showed that the amount of fiber has a greater effect on the tensile strength an d tensile strain capacity than the compressive strength, an d the tensile strain capacity was improved by using hybrid fibers. It was also found that the amount of steel fiber had a great influence on the impact resistance capacity of panels. Although the impact resistance capacity of panels could be improved by using hybrid fibers, the difference of impact resistance capacity between specimens was found to be larger than the case of use of single fiber.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.220.2-220.2
• /
• 2014

플라즈마 질화 기술은 기존의 침탄 혹은 고주파 표면 경화 기술 대비 낮은 온도에서 열처리 공정이 진행됨에 따라 열 변형을 최소화 시킬 수 있으며, 후 가공을 간소화 시킬 수 있다는 장점으로 인해 자동차 부품 및 기타 응용 산업 분야에 있어 큰 관심을 받고 있다. 그러나 공정 진행에 장시간이 소요되고 복잡한 형상 및 홀 가공에 의한 기능부, 특히 내경부에 대한 균일 질화 처리가 어려워 실제 응용분야 확장에 큰 제약이 따르고 있다. 이를 해결하기 위해 본 연구에서는 일반 글로우 방전 대비 플라즈마 밀도가 10배 이상 높은 공공 음극 방전(Hollow Cathode Discharge, 이하 HCD) 현상을 이용하여 고속 고균일 질화공정을 개발하고자 하였으며, 상용화 적용을 위한 연구를 함께 진행하였다. 사용된 시료로는 실제 자동차 부품으로 사용되는 SCM415 소재의 ring gear와 slip yoke pipe를 사용하였으며, HCD 형성을 위해 특화된 플라즈마 질화장비를 활용, 공정 압력 및 인가 전력 등을 변수로 실험을 진행 하였다. 그 결과 질화 처리 속도에 있어 기존 글로우 방전 플라즈마 질화 대비 1/4 이하 수준으로 그 소요 시간을 단축시킬 수 있었으며, 다량 장입된 시료의 내경 기능부에 있어서도 높은 균일도를 갖는 질화표면이 형성됨을 확인할 수 있었다. 또한 기능부 표면에 형성된 HCD 현상을 열원으로 사용함으로써 외부가열 장치를 사용하지 않으면서도 기존의 hot wall 방식보다 높은 질화 균일도 구현이 가능하였으며, 소요 자원 및 전력 사용 측면에 있어서도 공정 시간 단축 및 외부 가열 공정 제거에 의한 높은 수준의 에너지 절약이 가능하였다.

• The KIPS Transactions:PartB
• /
• v.8B no.6
• /
• pp.651-656
• /
• 2001

In this paper, we propose Improved Self-Organized Graph(Improved SOG：$SOG^*$)thinning method, which maintains the excellent thinning results of Self-organized graph(SOG) built from Self-Organizing features map and improves the performance of modified SOG using a new incremental learning method of Kohonen features map. In the experiments, this method shows the thinning results equal to those of SOG and the time complexity O((logM)3) superior to it. Therefore, the proposed method is useful for the feature extraction from digits and characters in the preprocessing step.