• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.63-68
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• 2000

A very large floating structure has rather small motion characteristics as to the whole body, while the motion at end part of such structure becomes largest due to the elastic motion of the structure. This paper presents on the theoretical result on the relative motion characteristics and green water phenomena of VLFS in waves This phenomena affect not only to strength of the structure but also the determination of depth of structure. To predict motion responses of structure in regular waves, the source-dipole distribution method and F.E.M is used By irregular wave results, the probability of occurrence of green water and response of the structure were calculated.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.21-24
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• 2002

This paper presents a new method for the motion detection of vehicles using hierarchical motion estimation and parallel processing. It captures the road image by using a CMOS sensor. It divides the captured image into small blocks and detects the motion of each block by using a block-matching method which is based on a hierarchical motion estimation and parallel processing for the real-time processing. The parallelism is achieved by using the pipeline and the data flow technique. The proposed method has been implemented with an embedded system. Experimental results show that the proposed method detects the motion of vehicles in real-time.

• Journal of Broadcast Engineering
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• v.9 no.1
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• pp.54-63
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• 2004

A new motion compensated frame Interpolation (MCI) algorithm by block based motion estimation (BME) is proposed. The block for the BME is composed of a large overlapped block for practical object motion estimation (ME) and a small block (which has a coinciding center with the ME-block) for the more precise motion compensated image description. Pixels in the block for the ME are sub-sampled to reduce computational complexity. The proposed method is executed with the various ME-blocks which have different size and sub-sampling ratio, and compared to the conventional method.

• Journal of Aerospace System Engineering
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• v.11 no.1
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• pp.41-46
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• 2017

A new test bench for small multi-rotor type drones has been developed. Six degrees of freedom (DOF) motion is possible due to a ball bushing, wheels, and rotating plates. An FPGA (field programmable gate array) based controller, that supports realtime parallel processing, is used to measure attitude with an accelerometer and a gyro to adjust motor speed. Several tests were performed to check the operational properties of the test bench and the controller. The results show that this test bench is proper for verifying controllers and the control methods of small multi-rotor drones.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1420-1427
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• 2023

Seismic risk has received increased attention since the 2011 Fukushima accident in Japan. The seismic risk of a nuclear power plant is evaluated via seismic probabilistic safety assessment (PSA), for which several methods are available. Recently, the discrete approach has become widely used. This approximates the seismic risk by discretizing the ground motion level interval into a small number of subintervals with the expectation of providing a conservative result. The present study examines the effect of the number of subintervals upon the results of seismic risk quantification. It is demonstrated that a small number of subintervals may lead to either an underestimation or overestimation of the seismic risk depending on the ground motion level. The present paper also provides a method for finding the boundaries between overestimation and underestimation regions, and illustrates the effect of the number of subintervals upon the seismic risk evaluation with an example. By providing a method for determining the effect of a small number of subintervals upon the results of seismic risk quantification, the present study will assist seismic PSA analysts to determine the appropriate number of subintervals and to better understand seismic risk quantification.

• Journal of the Ergonomics Society of Korea
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• v.30 no.6
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• pp.757-764
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• 2011

Objective: The aim of this study was to provide a method to improve the compliance and reduce the time by reducing the workload during the model change work. Background: The enterprises are constructing the small quantity batch production system by increasing the number of model change and reducing model-changing. However, the compliance is low because the work is strenuous and high skills are needed, so the system management is facing with many difficulties. Method: After classifying the model change work according to the purposes(preparation, change and adjustment) with the target of mascara filling machine, element tasks time were measured and the motion analysis(therblig symbol) and REBA analysis were performed. The study incorporated 3 independent variables as the number of motion, REBA score and the element time. The dependent variable is the type of element work as preparation, change and adjustment. The statistical test was performed by one-way ANOVA(${\alpha}$ < 0.05). Results: For the preparation, the number of motions appeared in the order of Use(U), Transport Loaded(TL), and Position(P). The order appeared in change is Use(U), Release Load(RL), and Grasp (G). The adjustment appeared in the order of Position(P) and Use(U). The results of average motion time as the element work times divided by the number of motion appeared in the order of adjustment(1.85sec/motion), preparation(1.11sec/motion), and change(0.62sec/motion). The results of REBA showed that the average risk level of change and adjustment were medium, but 53.1% of change and 42.9% of adjustment were evaluated as high. Conclusion: Reducing the avoidance and improving the compliance of work could be expected if the job autonomy were improved by improving the working postures with high risk level. Application: It is expected to solve the problem of reducing the time of model change work in the small quantity batch production system. The future work is to carry out the improvement directions found in the results and compare the results after improvement.

• The KIPS Transactions:PartB
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• v.10B no.3
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• pp.321-328
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• 2003

This Paper Proposes a size-variable block matching algorithm for motion vector extraction. The Proposed algorithm dynamically determines the search area and the size of a block. We exploit the constraint of small velocity changes of a block along the time to determine the origin of the search area. The range of the search area is adjusted according to the motion coherency of spatially neighboring blocks. The process of determining the sire of a block begins matching with a small block. If the matching degree is not good enough, we expand the size of a block a little bit and then repeat the matching process until our matching criterion Is satisfied. The experimental results show that the proposed algorithm can yield very accurate block motion vectors. Our algorithm outperforms other algorithms in terms of the estimated motion vectors, though our algorithm requires some computational overhead.

• Proceedings of the Korean Statistical Society Conference
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• 2003.05a
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• pp.37-42
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• 2003

We study the asymptotic expansion in small time of the mean distance of Brownian motion on Riemannian manifolds. We compute the first four terms of the asymptotic expansion of the mean distance by using the decomposition of Laplacian into homogeneous components. This expansion can he expressed in terms of the scalar valued curvature invariants of order 2, 4, 6.

• Journal of the Korean Professional Engineers Association
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• v.16 no.3
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• pp.33-40
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• 1983

This paper is one of the case studies to improve the labor productivity of PCB assembly through Work Factor motion-time analysis and the application of the motion economy principles and the human factors engineering theory. In result, we can improve 129％ of the labor productivity by using a rotary table for the parts delivery. Therefore, it is expected that this result can be used for a lot of the manual works of the small and medium-sized industries especially.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.948-953
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• 2004

For stable walking of various biped walking robots(BWR), we need to know the kinematics, dynamics and the Zero Moment of Point(ZMP) which are not easy to analyze analytically. In this reason, we developed a simulation program for BWRs composed of 4 degree-of-freedom upper-part body and 12 degree-of-freedom lower-part of the body. To operate the motion simulator for analyzing the kinematics and dynamics of BWES, inputs for the distance between legs, base angle, choice of walking type, gaits, and walking velocity are necessary. As a result, if stability condition is satisfied by the simulation, angle data for each actuator are generated automatically, and the data are transmitted to BWRS and then, they are actuated by the motion data. Finally, we validate the performance of the proposed motion simulator by applying it to a constructed small sized BWR.