• Journal of The Korean Association of Information Education
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• v.12 no.1
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• pp.41-48
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• 2008

Current performance evaluation of the natural science section mainly focuses on teacher evaluation, which causes slow feedback on the evaluation result and little evaluation on colleagues due to limits of time and space. In addition, report performance evaluation, which is a main target of the evaluation in the natural science section, is conducted mostly based on records of experiments and observation without any systematic forms. Such performance evaluation cannot meet expectation on the evaluation for a self-adjustment through instant feedback on the evaluation result and improvement of motivation through sharing common performance standard. Therefore, the study here completes an experiment/research report through information sharing and discussion among colleague learners based on the web and uses it for colleague or teacher evaluation. In addition, it is intended to recognize needs of learners and develop a performance evaluation system that can provide learners with appropriate feedback through the result.

• Journal of Convergence for Information Technology
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• v.7 no.5
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• pp.137-148
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• 2017

Recently, researchers are actively addressed to utilize Unmanned Aerial Vehicles(UAV) for military and industry applications. One of these applications is to trace the preceding flight when it is necessary to track the route of the suspicious reconnaissance aircraft in secret, and it is necessary to estimate the attitude of the target flight such as Roll, Yaw, and Pitch angles in each instant. In this paper, we propose a method for estimating in real time the attitude of a target aircraft using the video information that is provide by an external camera of a following aircraft. Various image processing methods such as color space division, template matching, and statistical methods such as linear regression were applied to detect and estimate key points and Euler angles. As a result of comparing the X-plane flight data with the estimated flight data through the simulation experiment, it is shown that the proposed method can be an effective method to estimate the flight attitude information of the previous flight.

• The Journal of the Korea Contents Association
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• v.14 no.2
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• pp.84-93
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• 2014

Comics uses words to convey its content and meaning, while the comic image conveys the content as a narrative function to represent how language is combined with the text. This paper makes a comparison and analysis of the comics of Japan and South Korea, in terms of words and image expression, narrative techniques, and the way of communication, to study the characteristics of image narrative. The comic image of Jing ke is the other as a flow of narrative and getting rid of the current screen, to resonate with the readers. Go U-yeong's comics and Sumeragi Natsuki's set up a virtual narrative time and space through the line, surface, space and shade, to realize the reproduction of unhistorical facts and the significance of narrative with the artist's imagination. Sumeragi Natsuki's comics uses historical facts to represent exquisite narrative like still-life paintings. She focuses on the description of the objective facts of history, to seek the sensitive comic image beyond reality. The image narration of Go U-yeong's comics is a clash between his historical narrative among the subjective romantic image and the readers' awareness narrative flow that they insist inside. Therefore, he tries to keep balance. The instant image in his comics is not a reproduction of the historical real moment, but a reproduction image of the reality reconstructed by his own pursuit of narrative.

• Journal of the Korea Fashion and Costume Design Association
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• v.5 no.2
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• pp.75-91
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• 2003

This study analyzed descriptions about dots, lines, and sides which are used as a basic elements to express geometric figures as followings: -In the aspect of formative art, dots form images and feelings through their concurrence when make a slight move to coordinates. The concurrence can bring out either positive or negative images; -Lines have unlimited variation as a core measure in body art. They can make optimal effects with different lines such as straight and curved lines of human body; -Sides express not only effects of texture and perspective but also of space and solid by color effects. Expressive characteristics and geometric shapes can be classified by tattoo, henna and body painting: First, colorful tattoos are favored by Caucasian and original tattoos are mostly used by yellow and colored races in the way of scarification to get decorative effects. Recently, a rapid cycle of fashion change in tattoo figures has developed a tentative method of tattooing and a variety of decoration methods. It has made it a lot easier to change a pattern of a tattoo. Tattoos are now popular among people because they no longer have to suffer from pains when they get their body tattooed for a long time. Since tattoos boast their unique beauty which consists of most dynamic and attractive images among the types of body art. It will be one of the most favored make-up methods in the nearest future. Second, geometric designs used in henna include crosses, dots, straight lines, triangles, date palms, and so on. Henna has been particularly loved as an instant decoration by the public since it gradually disappears as time goes on. Third, body painting enables to draw a three-dimensional effect because of its close relation with body movements in a limited space. Each individual will have a different feeling appealed in their body painting. Body painting has been applied to many different areas, especially to theatrical art using lights, music and performance altogether producing impromptu and experimental works. Unlike other arts such as painting, sculpture, visual and industrial arts, body painting has mobility. Since it is painted on a three-dimensional human body, it can bear originality expressing realistic objects or animals and strengthen creative functions using body lines. Moreover, geometric designs can be diversified by the sexes. As a result of analysis, geometric designs expressed in body art seemed to transcend expressions of beauty and turned out to be another way of decoration. Body art has also been used as a way to express visual integration and consolidation dynamically not by human instinct but by social changes. The needs for body art will grow as the future comes nearer and be recognized as a new and fresh value. Formative elements of geometric figures deliver visual impressions combined with human body and finally create more various types of body art in harmony of body lines.

• International Journal of Aeronautical and Space Sciences
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• v.8 no.1
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• pp.10-20
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• 2007

For spacecraft attitude control, reaction wheel (RW) steering laws with more than three wheels for three-axis attitude control can be derived by using a control allocation (CA) approach.1-2 The CA technique deals with a problem of distributing a given control demand to available sets of actuators.3-4 There are many references for CA with applications to aerospace systems. For spacecraft, the control torque command for three body-fixed reference frames can be constructed by a combination of multiple wheels, usually four-wheel pyramid sets. Multi-wheel configurations can be exploited to satisfy a body-axis control torque requirement while satisfying objectives such as minimum control energy.1-2 In general, the reaction wheel steering laws determine required torque command for each wheel in the form of matrix pseudo-inverse. In general, the attitude control command is generated in the form of a feedback control. The spacecraft body angular rate measured by gyros is used to estimate angular displacement also.⁵ Combination of the body angular rate and attitude parameters such as quaternion and MRPs(Modified Rodrigues Parameters) is typically used in synthesizing the control command which should be produced by RWs.¹ The attitude sensor signals are usually corrupted by noise; gyros tend to contain errors such as drift and random noise. The attitude determination system can estimate such errors, and provide best true signals for feedback control.⁶ Even if the attitude determination system, for instance, sophisticated algorithm such as the EKF(Extended Kalman Filter) algorithm⁶, can eliminate the errors efficiently, it is quite probable that the control command still contains noise sources. The noise and/or other high frequency components in the control command would cause the wheel speed to change in an undesirable manner. The closed-loop system, governed by the feedback control law, is also directly affected by the noise due to imperfect sensor characteristics. The noise components in the sensor signal should be mitigated so that the control command is isolated from the noise effect. This can be done by adding a filter to the sensor output or preventing rapid change in the control command. Dynamic control allocation(DCA), recently studied by Härkegård, is to distribute the control command in the sense of dynamics⁴: the allocation is made over a certain time interval, not a fixed time instant. The dynamic behavior of the control command is taken into account in the course of distributing the control command. Not only the control command requirement, but also variation of the control command over a sampling interval is included in the performance criterion to be optimized. The result is a control command in the form of a finite difference equation over the given time interval.⁴ It results in a filter dynamics by taking the previous control command into account for the synthesis of current control command. Stability of the proposed dynamic control allocation (CA) approach was proved to ensure the control command is bounded at the steady-state. In this study, we extended the results presented in Ref. 4 by adding a two-step dynamic CA term in deriving the control allocation law. Also, the strict equality constraint, between the virtual and actual control inputs, is relaxed in order to construct control command with a smooth profile. The proposed DCA technique is applied to a spacecraft attitude control problem. The sensor noise and/or irregular signals, which are existent in most of spacecraft attitude sensors, can be handled effectively by the proposed approach.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.9
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• pp.607-616
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• 2019

Free body diagram analysis is done for key parts of pilot stage of LLV (Load Limit Valve) which is used to protect overload for static structural test of aerospace flight vehicle. It is shown through the analysis that diameter ratio($D_2)^{ten}/D_2)^{comp}$) of two poppets in a pilot stage must be equal to piston area ratio($A_{comp}/A_{ten}$) of a hydraulic actuator for making a poppet open consistently at constant force applied by an actuator. The result of the analysis is verified by measuring geometries of the poppets in the four different LLVs which are corresponding to four actuators with different capacity and have been used after being imported in this laboratory. Results of "Adjuster resolution tests" with two different pilot stages show the max. deviation of Fi(actuator force in instant of opening poppet) from average Fi obtained for each turn of adjuster is 0.3KN and max. deviation of the Fi normalized by average Fi of each turn of adjuster is 3.7%. From the results, it is verified that the two pilot stages with same poppet diameter ratio make a poppet consistently open at Fis within ${\pm}3.7%$ deviation from the average Fi. The deviation is shown to be caused from frictional force of O-ring in the poppet. Additionally, design factors for poppet spring and adjuster, which are also key parts of the pilot stage, are distinguished and procedure for deciding the factors are also shown in this study.

• Cartoon and Animation Studies
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• s.19
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• pp.127-143
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• 2010

The purpose of this study is to aesthetically approach a game, which was popular at home, through microscopic analysis on World of Warcraft. World of Warcraft(hereunder called WOW), which improved a game method of MMORPG that had been popular conventionally at home, from several angles, is suggesting new paradigm of MMORPG game. This study aims to propose new vision on game analysis by approaching this new method from the perspective of player. For this, it divided WOW into shift method, instruction implementation method, and communication configuration method, and analyzed this, respectively, by introducing a concept of empty time, empty space, and non-place, which was borrowed from Zygmunt Bauman's "Liquid Modernity". WOW's shifting method rather extends empty time, that is, the waiting time, contrary to the conventional MMORPG, which used a method of removing. Instead of maximally reducing boring, which becomes disturbance of a game, it is what overwhelmingly enlarges time that needs to be waited, thereby being what induces a sense of time, which a player experiences daily life, to the inside of a game. WOW's instruction implementation method offers one of hugely single map instead of zone-system necessary for map loading in the discontinued form. This minutely implements even a greatly insignificant place in playing a game, thereby stirring up a sense of travel, which explores there in reality. Finally, WOW's community configuration method makes a hunting-targeted group clear, which added a concept of hunting called the raid to the existing gild system. The raid, which is a large party of being bound to the inside of Instant Dungeon, clearly gives a performance role to each of party members, thereby allowing the identity in character to be connected directly to the identity of player. Through this, the player filled the suggested 'space' with experience, thereby being able to change it into 'place' that is significant to an individual.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.2886-2894
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• 2012

This study is intended to research female university students' concern with beauty care, their skin condition, knowledge and treatment comparing the majors with the non-majors in Seoul. This comparative study between them focused on their educational and behavioral differences in beauty care in the same living space, and the results were as follows: The majors' average point on the concern with skin health care was higher than the non-majors(p<.01). There were more combination skin type in the major group, and more dry skin type in the non-major group. Also, there were meaningful differences among the two groups in frequency of double cleansing after makeup, exfoliating, massaging or applying mask packs, using sunscreen(p<.01, p<.001, p<.01, p<.01). Further, intake rates of instant food and moisture were meaningfully different between them(p<.001, p<.05). In addition, the majors more tended to purchase cosmetics efficiently through lots of channels, and showed more active attitude to buy high-price cosmetics with outstanding properties although they have financial burden(p<.001). It was hoped that the results of this study would be used in skin care industry and education area in the future.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.76-84
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• 2013

In the passive emitter localization using instantaneous TDOA (time difference of arrival) and FDOA (frequency difference of arrival) measurements, the estimation accuracy can be improved by collecting additional measurements. To achieve this goal, it is required to increase the number of the sensors. However, in electronic warfare environment, a large number of sensors cause the loss of military strength due to high probability of intercept. Also, the additional processes should be considered such as the data link and the clock synchronization between the sensors. Hence, in this paper, the passive localization of a stationary emitter is presented by using the successive TDOA and FDOA measurements from two moving sensors. In this case, since an independent pair of sensors is added in the data set at every instant of measurement, each pair of sensors does not share the common reference sensor. Therefore, the QCLS (quadratic correction least squares) methods cannot be applied, in which all pairs of sensor should include the common reference sensor. For this reason, a Gauss-Newton algorithm is adopted to solve the non-linear least square problem. In addition, to show the performance of the proposed method, we compare the RMSE (root mean square error) of the estimates with CRLB (Cramer-Rao lower bound) and derived the CEP (circular error probable) planes to analyze the expected estimation performance on the 2-dimensional space.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.3
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• pp.103-113
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• 2013

Shock wave model describes the propagation speed of kinematic waves in traffic flow. It was first presented by Lighthill and Whitham and has been deployed to solve many traffic problems. A recent paper pointed out that there are some traffic situations in which shock waves are not observable in the field, whereas the model predicts the existence of waves. The paper attempted to identify how such a counterintuitive conclusion results from the L-W model, and resolved the problem by deriving a new asymptotical shock wave model. Although the asymptotical model successfully eliminated the paradox of the L-W model, the validation of the new model is confined within the realm of the deceleration flow situation since the model was derived under such constraint. The purpose of this paper is to derive the remaining counter asymptotical shock wave model for acceleration traffic flow. For this, the vehicle trajectories in a time-space diagram modified to accommodate the continuously increased speed at every instant in such a way that the relationship between the spacing from the preceding vehicle and the speed of the following vehicle strictly follows Greenshield's model. To verify the validity of the suggested model, it was initially implemented to a constant flow where no shock wave exists, and the results showed that there exists no imaginary shock wave in a homogeneous flow. Numerical applications of the new model showed that the shock wave speeds of the asymptotical model for the acceleration flow tend to lean far toward the forward direction consistently. This means that the asymptotical models performs in a systematically different way for acceleration and for declaration flows. Since the output difference among the models is so distinct and systematic, further study on identifying which model is more applicable to an empirical site is recommended.