• Journal of the Korea Computer Graphics Society
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• v.21 no.1
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• pp.23-31
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• 2015

We present a method for creating realistic 2D stick figure animations easily and rapidly using captured motion data. Stick figure animations are typically created by drawing a single pose for each frame manually for the entire time interval. In contrast, our method allows the user to summarize an action (e.g. kick, jump) for an extended period of time into a single image in which one or more action lines are drawn over a stick figure to represent the moving directions of body parts. In order to synthesize a series of time-varying poses automatically from the given image, our system first builds a deformable character model that can make arbitrary deformations of the user's stick figure drawing in 2D plane. Then, the system searches for an optimal motion segment that best fits the given pose and action lines from pre-recorded motion database. Deforming the character model to imitate the retrieved motion segment produces the final stick figure animation. We demonstrate the usefulness of our method in creating interesting stick figure animations with little effort through experiments using a variety of stick figure styles and captured motion data.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.2
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• pp.186-190
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• 2015

Intelligent vehicle plans motion and navigate itself based on the surrounding environment perception. Hence, the precise environment recognition is an essential part of self-driving vehicle. There exist many vulnerable road users (e.g. vehicle, pedestrians) on vehicular driving environment, the vehicle must percept all the dynamic obstacles accurately for safety. In this paper, we propose an multiple vehicle tracking algorithm using microwave radar. Our proposed system includes various special features. First, exceptional radar measurement model for vehicle, concentrated on the corner, is described by mixture density network (MDN), and applied to particle filter weighting. Also, to conquer the curse of dimensionality of particle filter and estimate the time-varying number of multi-target states, reversible jump markov chain monte carlo (RJMCMC) is used to sampling step of the proposed algorithm. The robustness of the proposed algorithm is demonstrated through several computer simulations.

• Journal of KIISE:Information Networking
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• v.30 no.1
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• pp.9-16
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• 2003

In this paper, we propose a method for supporting VCR operations in a patching based multicast VOD system. Random access, pause and resume operations are supported in our system, and the channel and session scheduling algorithms for the VCR operations are proposed. When it is necessary to join a sharable multicast channel in the admission control for the VCR operations, the patching technique, which shares an on-going regular channel and allocates a new patching channel for the missing data, is used. Therefore, unlike the previous approach that allocates an excessive number of I-channels, service latency is minimized and channel usage is optimized in our system. Moreover buffered data. which is saved in disk during patching, is reused to prevent unnecessary patching channel allocation. For this. the patching management information is extended and a buffed data management scheme is proposed. In our system, the First-Come-First-Served scheduling is used to inform clients the service latency for the VCR operations immediately.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.6
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• pp.562-570
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• 2009

An Experimental study was conducted on the flow characteristics and interference heating caused by a two-dimensional object protruding from a flat plate using a blow-down type of hypersonic wind tunnel. Inflow condition was a free-stream Mach number of 7.0 and a unit Reynolds number of $2.0{\times}10^6/m$. Experimental conditions were varied with three heights of protuberance for two flat plate models which have different lengths. Experimental data were obtained from Schlieren visualization images and heat flux measurements. Also, this paper suggests hypersonic experimental techniques such as boundary-layer detection method in detail. A Large separation region was observed in front of the protuberance and that region was very sensitive to the height of protuberance and the length of the flat plate. For only the highest protuberance, a severe jump of heat flux was observed at the top station among the measuring points. Measured heat flux is large when the height of protuberance is large and the length of flat plate is long.

• Korean Journal of Applied Biomechanics
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• v.22 no.4
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• pp.379-386
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• 2012

The aim of this study was to investigate and identify the differences in lower extremity energy dissipation strategies between drop-landing and countermovement-jump maneuvers. Fourteen recreational athletes(Age : $23.3{\pm}2.1years$, Height : $172.3{\pm}4.0cm$, Weight : $69.2{\pm}4.7kg$) were recruited and instructed to perform drop-landing from 45 cm height and countermovement-jump from 45 cm to 20 cm height. The landing phase was taken as the time between initial contact and peak knee flexion. A motion-capture system consisting of eight infra-red cameras was employed to collect kinematics data at a sampling rate of 200 Hz and a force-plate was used to collect GRF data at a sampling rate of 2000 Hz. Paired t-test was performed to determine the difference in kinematics and kinetics variables between each task. During the countermovement-jump task, all of lower extremity joint ROM and the hip joint eccentric moment were decreased and the ankle joint plantarflexion moment was increased than drop-landing task. In the eccentric work during countermovement-jump task, the ankle joint displayed greater while knee and hip joint showed lesser than drop-landing. Therefore, the knee joint acted as the key energy dissipater during drop-landing while the ankle joint contributed the most energy dissipation during countermovement-jump. Our findings collectively indicated that different energy dissipation strategies were adopted for drop-landing and countermovement-jump.

• New Physics: Sae Mulli
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• v.68 no.12
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• pp.1364-1373
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• 2018

A recognizable form having meaning is called a sign in semiotics. The sign is transformed into a physical counter form in this work. Its internal structure is restricted on the linguistic concept structure. We borrow the concept of a mathematical function from the utility function of a rational personal in the economy. Universalizing the utility function by introducing the consistency of independency on the manner of construction, we construct the probability. We introduce a random variable for the probability and join it to a position variable. Thus, we propose a physical sign and its serial changes in the forms of stochastic equations. The equations estimate three patterns (jumping, drifting, diffusing) of possible solutions, and we find them in the one-day stock-price flow. The periods of jumping, drifting and diffusing were about 2, 3.5, and 6 minutes for the Kia stock on 11/05/2014. Also, the semiotic sign (icon, index, symbol) can be expected from the equations.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.4
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• pp.55-63
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• 1995

This paper describes the procedure to analyze the performance of the end-plated propeller(EPP) by a boundary integral method. The screw blade(SB) and end-plate(EP) are represented by a set of quadrilateral panels, where the source and normal dipole of uniform strength are distributed. The perturbation velocity potential, being the only unknown via the potential-based formulation, is determined by satisfying the flow tangency condition on the blade and the end-plate at the same time. The Kutta condition is satisfied through an iterative process by requiring the null pressure jump across the upper and lower sides of the trailing edges of both the SH and the EP. Sample calculations indicate that the EP increases the loading near the tip of the SB while spreading the trailing vortices along the trailing edge of the EP, thus avoiding the strong tip-vortex formation. Predicted performance of the EPP shows good correlations with the experimental results. The method is therefore considered applicable in designing and analyzing the EPP which may be an alternative for energy-saving propulsive devices.

• PNF and Movement
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• v.13 no.3
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• pp.135-143
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• 2015

Purpose: The purpose of this study was to assess the effect of the proprioceptive neuromuscular facilitation (PNF) relaxation technique (hold relax; HR, contract relax; CR) and static stretch (SS) on hamstring flexibility and vertical jump performance in healthy adults over a four-week period. Methods: Twenty-four healthy adults volunteered to participate in PNF and static stretch sessions. The subjects were divided into three groups as follows: 8 subjects in the SS group, 8 subjects in the HR group, and 8 subjects in the CR group. In the HR and CR groups, contractions lasted 15 seconds per trial and consisted of 5 sets of 15 seconds of hamstring contraction immediately followed by 15 seconds of passive static hamstring stretching. For the static group, the participants were asked to stretch by hanging a leg over a table for 30 seconds. Subjects in all groups performed the exercises three days per week for 4 weeks. The active straight leg raising (ASLR) test, active knee extension (AKE) test, and vertical jump test were performed before the intervention and after 1, 2, and 4 weeks. Results: The SS, HR, and CR techniques effected positive improvement in hamstring flexibility and vertical jump performances but neither of the stretching methods had any statistically significant different effects according to group, although there were interactions (between group and time) in the ALSR group from 1 week to 2 week and in the AKE test from pretest to 1 week. Conclusion: Based on the results of the current study, SS, HR, and CR were shown to affect hamstring flexibility and vertical jump performance in healthy adults. In particular, it was determined that within a short period, hamstring flexibility could be attributed more to CR than to SS.

• Journal of Digital Convergence
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• v.17 no.9
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• pp.79-88
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• 2019

This study analyzes the influential factors and patterns associated with death from aircraft accidents and incidents using data mining techniques. To this end, we used two datasets for aircraft accidents and incidents, one from the National Transportation Safety Board (NTSB) and the other from the Federal Aviation Administration (FAA). We developed our prediction models using the decision tree classifier to predict death from aircraft accidents or aircraft incidents and thereby derive the main cause factors and patterns that can cause death based on these prediction models. In the NTSB data, deaths occurred frequently when the aircraft was destroyed or people were performing dangerous missions or maneuver. In the FAA data, deaths were mainly caused by pilots who were less skilled or less qualified when their aircraft were partially destroyed. Several death-related patterns were also found for parachute jumping and aircraft ascending and descending phases. Using the derived patterns, we proposed helpful strategies to prevent death from the aircraft accidents or incidents.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.143-149
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• 2019

Floating holograms are technologies that provide rich 3D stereoscopic images in a wide space such as advertisement, concert. In addition, It is possible to reduce the 3D glasses inconvenience, eye strain, and space distortion, and to enjoy 3D images with excellent realism and existence. Therefore, this paper implements a user gesture recognition system for manipulating a floating hologram characters that can be used in a small space devices. The proposed method detects face region using haar feature-based cascade classifier, and recognizes the user gestures using a user gesture-occurred position information that is acquired from the gesture difference image in real time. And Each classified gesture information is mapped to the character motion in floating hologram for manipulating a character action. In order to evaluate the performance of the proposed user gesture recognition system for manipulating a floating hologram character, we make the floating hologram display devise, and measures the recognition rate of each gesture repeatedly that includes body shaking, walking, hand shaking, and jumping. As a results, the average recognition rate was 88%.