• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.2
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• pp.49-56
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• 2009

In this study, a side collision accident reconstruction using database based on the deformed shape information from the collision test using model cars is suggested. A deformation index and angle index related to the deformed shape is developed to set the database for the collision accident reconstruction algorithm. Two small size RC cars are developed to carry out the side collision test. Several side collision tests according to the velocity and collision angles are performed for establishing the side collision database. A high speed camera with 1000fps is used to capture the motion of the car. A side collision accident reconstruction algorithm is developed and applied to find the collision conditions before the accident occurs. Two collision cases are tested to validate the database and the algorithm. The results obtained by the reconstruction algorithm show good match with original conditions with regard to the velocity and angle.

• Smart Structures and Systems
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• v.9 no.3
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• pp.273-286
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• 2012

As civil structures are exposed to various external loads, it is essential to assess the structural condition, especially the structural displacement, in every moment. Therefore, a visually servoed paired structured light system was proposed in the previous study. The proposed system is composed of two screens facing with each other, each with a camera, a screen, and one or two lasers controlled by a 2-DOF manipulator. The 6-DOF displacement can be calculated from the positions of three projected laser beams and the rotation angles of the manipulators. In the estimation process, one of well-known iterative methods such as Newton-Raphson or extended Kalman filter (EKF) was used for each measurement. Although the proposed system with the aforementioned algorithms estimates the displacement with high accuracy, it takes relatively long computation time. Therefore, an incremental displacement estimation (IDE) algorithm which updates the previously estimated displacement based on the difference between the previous and the current observed data is newly proposed. To validate the performance of the proposed algorithm, simulations and experiments are performed. The results show that the proposed algorithm significantly reduces the computation time with the same level of accuracy compared to the EKF with multiple iterations.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.2
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• pp.214-223
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• 2000

In this research, a study on the characteristics of the liquid sheet formed by two impinging jets is presented. Using the interference phenomena of light, the thickness of the liquid sheet, which seems to heavily affect the size of the droplets, is measured and compared with existing theoretical modelings. Thinner liquid sheet is produced with larger impinging angle, smaller orifice diameter, and higher azimuthal angle but the jet velocity doesn't affect the thickness. More viscous liquid produces thicker liquid sheet. The theoretical modelings predict the same trend as the experiments but the thickness values are overestimated at low azimuthal angles. This difference is gradually decreased as the azimuthal angle is increased: The breakup mechanism of the droplets from the liquid sheet is visualized by a high speed camera. The crest around the edge of the liquid sheet is protruded with the accumulation of liquid at the end of protuberance, which contracts into a spherical shape and then becomes detached when the stem breaks down, producing large droplets with a few small size of satellites.

• Journal of Fashion Business
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• v.10 no.5
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• pp.1-14
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• 2006

The purpose of this study is to examine the style of Marlene Dietrich who was a Hollywood legend in 1930s and has influenced on modern fashion. The characteristics of Dietrich style showed androgyny, sensualism and exoticism. Dietrich has been famous for wearing tailored pantsuit on and off-screen with mannish gesture and had great effect on women's wearing pants. Her confident, sexy mannish style represented her androgyny glamourously and proved she had a taste for a classic. Her sensualism focused on her famous legs because she understood the sex appeal of woman's legs. She showed her legs by wearing pants and decorative stockings, or matching colors of stockings and shoes to make her legs look longer and sexier by illusion. Her exoticism against a backdrop of black and white image, was presented with luxurious, sensual fabrics such as furs, feathers and velvet, along with dazzling accessaries. Also she didn't forget to manipulate angles of camera and lights for the engraving figure of her own. Her charisma directed her fashion image in detail and made herself a fashion icon in 1930s.

• Transactions of Materials Processing
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• v.29 no.1
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• pp.20-26
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• 2020

In the design of the metal forming processes, various types of ductile fracture criteria are used to predict crack initiation and to fabricate metallic products without any defects. However, the quantitative measurement method for determination of crack initiation is insufficient. It is very difficult to detect crack initiation in ductile metals with excellent deformability because no significant load drop is observed due to crack generation. In this study, the applicability of acoustic emission sensors, which are commonly used in facility diagnostics, to measure crack initiation during the metal forming process was analyzed. Cylindrical notch specimens were designed using the finite element method to induce a premature crack on the surface of pre heat-treated steel (ESW90) material. In addition, specimens with various notch angles and heights were prepared and compression tests were carried out. During the compression tests, acoustic emission signal on the dies and images of the surface of the notch specimen were recorded using an optical camera in real time. The experimental results revealed that the acoustic emission sensor can be used to detect crack initiation in ductile metals due to severe plastic deformation.

• Korean Institute of Interior Design Journal
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• v.20 no.2
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• pp.64-71
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• 2011

There are a method to analyze reactions or psychological condition and a method to observe visitor's behavioral reaction as methods to measure and evaluate humans' recognition behavior reaction of humans. The measure of the eye movement as a method to living body's reaction and psychological condition has an advantage to measure the information acceptance reaction of view recognition of the stimulus of view composition factors which has been used since a long time ago in other research areas, but almost not studies have been made on the exhibition views in museums. Therefore, on the premise of such recognition, this study aimed at obtaining various types of information through vision angles of visitor in exhibition space of an museum and judging space information, at measuring the condition of information acceptance through attention experiments and observation investigation of and finding out the disposition and characteristics so as to verify the relationship between the exhibition space and exhibition Method.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.58-64
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• 2003

Dimethyl Ether(DME) has been considered as one of the most attractive alternative fuels for compression ignition engine. Its main advantage in diesel engine application is high efficiency of diesel cycle with soot free combustion though conventional fuel injection system has to be modified due to the physical properties of DME. Experimental study of DME and conventional diesel spray employing a common-rail type fuel injection system with a 5-hole sac type injector was performed in a constant volume vessel pressurized by nitrogen gas. Spray cone angles and penetrations of the DME spray were characterized and compared with those of diesel. For evaluation of the evaporating characteristics of the DME, shadowgraphy technique employing an Ar-ion laser and an ICCD camera was adopted. Tip of the DME spray was formed in mushroom-like shape at atmospheric chamber pressure, which disappeared in higher chamber pressure. Spray tip penetration and spray cone angle of the DME became similar to those of diesel under 3MPa of chamber pressure. Higher injection pressure provided wider vapor phase area while it decreased with higher chamber pressure condition.

• International Journal of Automotive Technology
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• v.7 no.5
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• pp.519-526
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• 2006

For investigating the effect of fuel stratification on flame propagation, initial flame development and propagation were visualized under different axially stratified states in a port injection SI engine. Stratification was controlled by the combination of the port swirl ratio and injection timing. Experiments were performed in an optical single cylinder engine modified from a production engine and images were captured through the quartz window mounted in the piston by an intensified CCD camera. Firstly in this paper, the characteristics under no port-generated swirl condition, i.e. normal conventional case was studied. Under various stratified conditions, flame images were captured at the pre-set crank angles. These were averaged and processed to characterize the flames propagation. The flame stability was estimated by the weighted average of flame area and luminosity. The stability was also evaluated through the standard deviation of flame area and propagation distance, and mean absolute deviation of propagating direction. Results show that stratification state according to injection timing do not affect on the direction of flame propagation. The flame development and the initial flame stability are strongly dependent on the stratified conditions and the initial flame stability is closely related to the engine stability and lean misfire limit.

• Journal of ILASS-Korea
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• v.18 no.4
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• pp.182-187
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• 2013

This study was performed to investigate the effect of biodiesel derived from waste cooking oil on the spray behavior and macroscopic spray characteristics. To analyze quantitative characteristics of test fuels, injection quantity was measured at various injection pressures and the spray images of injected fuels in the pressurized chamber were obtained by using a high speed camera and image analysis system. Based on the measured spray images, the spray tip penetration and spray cone angle were investigated at various energizing timings and injection pressures. In this work, the experimental results showed that the injection quantity of waste cooking biodiesel indicated the higher quantities than diesel at high injection pressure. As the injection pressure was increased, the spray tip penetrations of biodiesel were higher value than diesel. The difference of penetration between biodiesel and conventional diesel fuel was reduced in accordance with the increase of injection pressure. Also, the spray angles of diesel were larger than that of biodiesel because diesel fuel has lower viscosity than biodiesel. In addition, the spray evolution processes of biodiesel fuel at various injection pressures and the elapsed time after the injection were compared to the conventional diesel fuel.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.6
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• pp.579-583
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• 2012

The purpose of this paper is to suggest IDE (Incremental Displacement Estimation) algorithm for the previously proposed visually servoed paired structured light system. The system is composed of two sides facing with each other, each with one or two lasers with a 2-DOF manipulator, a camera, and a screen. The 6-DOF displacement between two sides can be estimated by calculating the positions of the projected laser beams and rotation angles of the manipulators. In the previous study, Newton-Raphson or EKF (Extended Kalman Filter) has been used as an estimation algorithm. Although the various experimental tests have validated the performance of the system and estimation algorithms, the computation time is relatively long since aforementioned algorithms are iterative methods. Therefore, in this paper, a non-iterative incremental displacement estimation algorithm which updates the previously estimated displacement with a difference of the previous and the current observed data is introduced. To verify the performance of the algorithm, experimental tests have been performed. The results show that the proposed non-iterative algorithm estimates the displacement with the same level of accuracy compared to the EKF with multiple iterations with significantly less computation time.