• The Journal of the Korea institute of electronic communication sciences
• /
• v.11 no.10
• /
• pp.955-962
• /
• 2016

In this paper, we propose a design method for speed controller, current control of a Brushless Direct Current(: BLDC) motor using disturbance rejection techniques. Disturbance assumes a back electromotive force occurring in the electrical system and the variation of the load acting on the rotary shaft from the outside of the motor. And it assumed to be constant during the time interval and the Luenberger's observer design. So that the error of the observer about the system status can converge to zero show how to set the appropriate gain. Further, to stabilize the whole system, and proposes a method for setting the appropriate PI gain control to improve the tracking performance. By applying the proposed controller to 120W BLDC motors were tested for the ability to follow the velocity and current reference. Since the simulation results of the steady state error is within 0.1%, we were able to show the usefulness of the tracking performance of the proposed controller.

• Computational Structural Engineering
• /
• v.1 no.2
• /
• pp.101-109
• /
• 1988

The evaluation of the system reliability is generally quite difficult and costly as the structure becomes large and complex, especially when it is subjected to multiple time varying loads, and for redundant structures which have many possible modes of failur, e.g., system collapse through the formation of plastic hinge mechanisms. In reality most loadings acting on the structures are random in intensity as well as in occurrence time and duration. To include the load variability in time, the loads are described in terms of stochastic processes. Based on a tri-modal upper bound, a point estimate for the system reliability has been developed for more accuracy without extensive computational effort. This tri-modal point estimate also ensures the continuity of the system reliability function, which is a necessary condition in many nonlinear programming techniques. In addition, the Load Coincidence method, by which the combined effect of time varying loads are taken into account, has been modified to suitable for cases with an always-on load.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.5 no.1
• /
• pp.3-11
• /
• 2003

Face stability of a tunnel is a main concern during tunnel excavation. However, there has been only a few studies on this problem while a lot of researches on the support systems have been carried out. In addition, when tunneling is performed below the groundwater level, the groundwater flows into the tunnel so that the seepage forces generated on the tunnel face might give rise to a serious potential for the face instability. In this study, the face stability was evaluated by simultaneously considering two factors: one is the effective stress calculated by upper bound theorem; the other is the seepage forces acting on the tunnel face obtained by numerical analysis under the condition of steady-state groundwater flow. Tunneling in difficult geological conditions often requires auxiliary techniques to guarantee safe tunnel excavations and/or to prevent damage to structures and services around the tunnel. The steel pipe-reinforced multistep grouting has been recently applied to tunnel sites in Korea. Face stability of a tunnel with the steel pipe-reinforced multistep grouting was also analyzed in this study.

• Journal of Internet Computing and Services
• /
• v.12 no.6
• /
• pp.83-94
• /
• 2011

Main researching issue in affective computing is to give a machine the ability to recognize the emotion of a person and to react it properly. Efforts in that direction have mainly focused on facial and oral cues to get emotions. Postures have been recently considered as well. This paper aims to discriminate emotions posture by identifying and measuring the saliency of posture features that play a role in affective expression. To do so, affective postures from human subjects are first collected using a motion capture system, then emotional features in posture are described with spatial ones. Through standard statistical techniques, we verified that there is a statistically significant correlation between the emotion intended by the acting subjects, and the emotion perceived by the observers. Discriminant Analysis are used to build affective posture predictive models and to measure the saliency of the proposed set of posture features in discriminating between 6 basic emotional states. The evaluation of proposed features and models are performed using a correlation between actor-observer's postures set. Quantitative experimental results show that proposed set of features discriminates well between emotions, and also that built predictive models perform well.

• The Journal of the Korea Contents Association
• /
• v.15 no.12
• /
• pp.50-60
• /
• 2015

The animation film , which became a worldwide sensation with its theme song 'Let it go', did not only rank first in the U.S. box office - it was also the greatest box office hit in the history of Disney animation. Why did , recreated into a musical animation, become a worldwide success and what were the characteristics of its materialized hybrid visual direction technique? In order to look into this, firstly, literature on musicals and animations were studied, and secondly, analysis standards were drawn for musical characteristics of musicals and direction techniques of animations. Thirdly, analyzation and investigation will be conducted on hybrid visual direction techniques based on the research above with as the example. Through this study, it's known that realizes its musical features such as 'exaggerated acting,' 'delivering the meaning of circumstances', 'dramatic expression of emotion' and etc. through animated characters and that its background music is aided by 'narrative features' through its musical composition. Besides, its snow effect through animated VFX composing scenes along with its musical characteristics realizes hybrid image direction. It can be said that image directing effects of musical animations through hybrid grafting and the characteristics of image aesthetics generate public demands worldwide.

• Korean Security Journal
• /
• no.48
• /
• pp.113-146
• /
• 2016

Criminal profiling is a effective and efficient measure for enhancing industrial security of casino business. Particularly, developing criminal profiling of deviant behaviors in casino will help security management to become more effective and efficient in practical ways. Unfortunately, however, there is lack of empirical profiling study in this regard. To fill the vacuum of literature on this topic, this study was purported to create offender profiles of different types of deviant behaviors in casino based on various theories and techniques in criminal profiling literature, such as investigative psychology, linkage analysis, and behavioral evidence analysis. To fulfill the purposes, this study collected behavioral evidence from 90 casino security officers in South Korea. Offenders' behavioral evidence was analyzed to develop offender profiles of seven different types of deviant behaviors, and then the profiles were compared with each profiles that security officers focus on to identify offenders during their work hours. Results showed that, first, there were unique profiles of each type of seven different categories of deviant behaviors in terms of offenders' ways of speaking and acting, their appearance and attitudes. In addition, this study found that there were some amount of gaps between actual offenders' profiles and profiles that security officers have in mind. Based on the results, this study provided policy implications in terms of managing casino industrial security, education and training for security officers, and future study on casino security.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.32 no.3
• /
• pp.180-201
• /
• 2020

It has been widely known that the effect of diffracted waves at the tip of composite breakwater with finite length causes the change of standing wave height along the length of breakwater, the spatial change of wave pressure on caisson, and the occurrence of meandering damage on the different sliding distance in sequence. It is hard to deal with the spatial change of wave force on trunk of breakwater through the two-dimensional experiment and/or numerical analysis. In this study, two and three-dimensional numerical techniques with olaFlow model are used to approach the spatial change of wave force including the impulsive breaking wave pressure applied to trunk of breakwater, the effect of rear region, and the occurrence of diffracted waves at the tip of caisson located on the high crested rubble mound. In addition, it is thoroughly studied the mean wave height, mean horizontal velocity, and mean turbulent kinetic energy through the numerical analysis. In conclusion, it is confirmed that the larger wave pressure occurs at the front wall of caisson around the still water level than the original design conditions when it generates the shock-crushing wave pressure checked by not two-dimensional analysis, but three-dimensional analysis through the change of wave pressure applied to the caisson along the length of breakwater.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.11
• /
• pp.1305-1310
• /
• 2012

The performance of a system can be affected by the variance of noise factors, which arise owing to uncertainties of the material properties and environmental factors acting on the system. For robust design optimization of the system performance, it is necessary to minimize the effect of the variance of the noise factors that are impossible to control. However, present robust design techniques consider the variation of design factors, and not the noise factors, as being important. Furthermore, it is necessary to assume a normal distribution; however, a normal distribution is often not suitable to estimate the variations. In this study, a robust design technique is proposed to consider the variation of noise factors that are estimated as non-normal distributions in a real experiment. As an example of an engineering problem, a deep-sea manganese nodule miner tracked vehicle is used to demonstrate the feasibility of the proposed method.

• The Journal of the Korea Contents Association
• /
• v.12 no.4
• /
• pp.143-155
• /
• 2012

The research was started out of curiosity for what made 's fast and trilling pace possible although it is an old movie. The center of what made it possible was its use of the Long Take - Long Take was used in all of the scenes and in some cases only long take was used. What is interesting is the film maker's use of various cinematic techniques to prevent the scene from being too slow and keep the audience immersed in the characters. In one shot, acting in addition to Mise-en-Sc$\grave{e}$ne were used to provide psychological immersion of character and scene. The use of Long Take, with the exception of some intentional scenes, was difficult to notice without conscience observation. All the components that make up Long Take. camera walking and lighting as well as actor's dialog and performance and scene movement all beautifully came together. The Long Take is generally replaced by many different sort shots. However, Mike Nichols clearly demonstrates the benefit of Long Take. In the movie, the general aesthetics from the use of Long Take is slightly altered for a different purpose. The specific methods and effects used in the application of Long Take is the subject of this study.

• Microbiology and Biotechnology Letters
• /
• v.40 no.2
• /
• pp.92-97
• /
• 2012

Antimicrobial peptides (AMPs) are important components of living organisms acting against Gram-negative and Gram-positive bacterial and fungal pathogens. Cathelicidin human peptides have a variety of biological activities that can be used in clinical applications. AMPs are not produced naturally in large quantities, and chemical synthesis is also economically impractical, especially for long peptides. Therefore, as an alternative, heterologous expression of AMPs by recombinant techniques has been studied as a means to reduce production costs. E. coli is an excellent host for the expression of AMPs, as well as other recombinant proteins, because of the low cost involved and its easy manipulation. However, overexpression of AMPs in E. coli has been shown to cause difficulties resulting from the toxicity of the subsequently produced AMPs. Therefore, fusion expression was theorized to be a solution to this problem. In this study, AMPs were expressed as fused proteins with the glutathione S-transferase (GST) binding protein to protect against the toxicity of AMPs when expressed in E. coli. The LL37, and hybrid gaegurin and LL37 (GGN4(1-16)-LL37(17-32), which we designated as GL32, peptides were expressed as GST-fusion proteins in E. coli and the fusion proteins were then purified by affinity columns. The purified peptides were obtained by removal of GST and were confirmed by western blot analysis. The purified antimicrobial peptides then demonstrated antimicrobial activities against Gram-negative and Gram-positive bacterial strains.