• Journal of Biomedical Engineering Research
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• v.18 no.1
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• pp.25-36
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• 1997

To regulate cardiac output of the Total Artificial Heart(TAH) physiologically, the hemodynamic information must be toed back to the controller. So far, our group has developed an automatic cardiac output control algorithm using the motor current waveform, It is, however difficult to detect the preload level such as a filling status of ventricular inflow and the variation of atrial pressures within normal physiologic range(0-15 mmHg) by analyzing the motor current which simultaneously reflects the afterload effect. On the other hin4 the interventricular volume pressure(IVP) which is not influenced by arterload but by preload is a good information source for the estimation of preload states. In order to find the relationship between preload and IVP waveform, we set up the artificial heart system on the Donovan type mock circulatory system and measured the IVP waveform, right and left atrial pressures, inflow and outflow waveforms and the signals represented the information of moving actuator's position. We shows the feasibility of estimating the hemodynamic changes of inflow by using IVP waveform. fife found that the negative peak value of IVP waveform is linearly related to atrial pressures. And we also found that we could use the time to reach the negative peak in IVP waveform, the time to open outflow valve, the area enclosed IVP waveform as unfu parameters to estimate blood filling volume of diastole ventricle. The suggested method has advantages of avoiding thrombogenesis, bacterial niche formation and increasing longterm reliability of sensor by avoiding direct contact to blood.

• Journal of Distribution Science
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• v.14 no.9
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• pp.133-147
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• 2016

Purpose - The Purpose of this study is to observe the value of LOHAS as an exhibition that is perceived to be a specialized local exhibition with good fame and differentiated advantage as well as the spectators' will to visit the exhibition coming from the future behavior intention of visitors. Research design, data, and methodology - In order to achieve the purpose of this study, This study organized questionnaire after setting a hypothesis based on the theoretical background from the parameters. verification of the hypothesis by statistically analyzing the answers for questionnaire follows. Finally, the implication of this study is drawn through comprehensive discussion while This study indicated from the limits of the study and future direction for research. This study set up a model to research the influence on the structuring factors in LOHAS exhibition in forming perceived value, customer satisfaction and future behavior intention. Frequency analysis was used for getting demographic characteristics, verification of plausibility, reliability of measured parameters and factors analysis. This study have performed verification of difference at selection property level based on multiple regression analysis and demographic nature. Results - To summarize the study result, through the verification of hypothesis about meaningful influence among structuring factors in LOHAS exhibition, perceived value and customer satisfaction shows some noticeable points to focus on. That is, it is established things that partial adoption and meaning relationship of partial influence. The perceived value affected both customer satisfaction and future behavior intention meaningfully. Conclusions - This study could note that in the structuring factors of LOHAS exhibition, perceived value for visitors and customer satisfaction play their roles positively on the future behavior intention. In conclusion, this study implies that strategic measures are necessary to fulfill the structuring factors of LOHAS exhibition as they would make positive impact on acknowledged value, customer satisfaction and future behavior intention to contribute to the growth and development of LOHAS exhibition. Also it suggests that the method to join each other with activities is necessary to strengthen the properties of the exhibition and position well to be a solid local exhibition.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.6
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• pp.806-813
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• 2010

Human facial expression shows human's emotion most exactly, so it can be used as the most efficient tool for delivering human's intention to computer. For fast and exact recognition of human's facial expression on a 2D image, this paper proposes a new method which integrates an Discrete Adaboost classification algorithm and a neural network based recognition algorithm. In the first step, Adaboost algorithm finds the position and size of a face in the input image. Second, input detected face image into 5 Adaboost strong classifiers which have been trained for each facial expressions. Finally, neural network based recognition algorithm which has been trained with the outputs of Adaboost strong classifiers determines final facial expression result. The proposed algorithm guarantees the realtime and enhanced accuracy by utilizing fastness and accuracy of Adaboost classification algorithm and reliability of neural network based recognition algorithm. In this paper, the proposed algorithm recognizes five facial expressions such as neutral, happiness, sadness, anger and surprise and achieves 86~95% of accuracy depending on the expression types in real time.

• Journal of the Korea Society for Simulation
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• v.29 no.2
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• pp.95-103
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• 2020

The structural connection design for lightweight structure application is presented in this paper. Modeling of the welding zone and the bolted connection are suggested. For reliability verification of the established models, nonlinear analysis is performed and comparisons are made with the experimental data showing good agreement. Through comparison study, suitable welding method for structure materials is investigated. Also, stability analysis is performed by fracture load simulation for different number and position of bolts. Finally, based on the structural connection models, the lightweight structure is modeled and structural analysis was performed. Stability analysis of structural connection for lightweight structure design, through combination of welding and bolting process, showed a 31.4% decrease in the maximum stress compared to the structure without the structural connections. Importance of structural connection design is highlighted for lightweight structure stability analysis.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.493-498
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• 2004

The objective of the present study is to compare various conventional and recently evolved satellite image-processing techniques and to ascertain the best possible technique that can identify and position of aquaculture farms accurately in and around the Younggwang coastal area. Several conventional techniques performed to extract such information fiom the Landsat-TM imagery do not seem to yield better information about the aquaculture farms, and lead to misclassification. The large errors between the actual and extracted aquaculture farm information are due to existence of spectral confusion and inadequate spatial resolution of the sensor. This leads to possible occurrence of mixture pixels or 'mixels' of the source of errors in the classification techniques. Understanding the confusing and mixture pixel problems requires the development of efficient methods that can enable more reliable extraction of aquaculture farm information. Thus, the more recently evolved methods such as the step-by-step partial spectral end-member extraction and linear spectral unmixing methods are introduced. The farmer one assumes that an end-member, which is often referred to as 'spectrally pure signature' of a target feature, does not appear to be a spectrally pure form, but always mix with the other features at certain proportions. The assumption of the linear spectral unmxing is that the measured reflectance of a pixel is the linear sum of the reflectance of the mixture components that make up that pixel. The classification accuracy of the step-by-step partial end-member extraction improved significantly compared to that obtained from the traditional supervised classifiers. However, this method did not distinguish the aquaculture ponds and non-aquaculture ponds within the region of the aquaculture farming areas. In contrast, the linear spectral unmixing model produced a set of fraction images for the aquaculture, water and soil. Of these, the aquaculture fraction yields good estimates about the proportion of the aquaculture farm in each pixel. The acquired proportion was compared with the values of NDVI and both are positively correlated (R$^2$ =0.91), indicating the reliability of the sub-pixel classification.ixel classification.

• Journal of Periodontal and Implant Science
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• v.47 no.1
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• pp.41-50
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• 2017

Purpose: The aims of the present study were to compare the image quality and visibility of tooth cracks between conventional methods and swept-source optical coherence tomography (SS-OCT) and to develop an automatic detection technique for tooth cracks by SS-OCT imaging. Methods: We evaluated SS-OCT with a near-infrared wavelength centered at 1,310 nm over a spectral bandwidth of 100 nm at a rate of 50 kHz as a new diagnostic tool for the detection of tooth cracks. The reliability of the SS-OCT images was verified by comparing the crack lines with those detected using conventional methods. After performing preprocessing of the obtained SS-OCT images to emphasize cracks, an algorithm was developed and verified to detect tooth cracks automatically. Results: The detection capability of SS-OCT was superior or comparable to that of trans-illumination, which did not discriminate among the cracks according to depth. Other conventional methods for the detection of tooth cracks did not sense initial cracks with a width of less than $100{\mu}m$. However, SS-OCT detected cracks of all sizes, ranging from craze lines to split teeth, and the crack lines were automatically detected in images using the Hough transform. Conclusions: We were able to distinguish structural cracks, craze lines, and split lines in tooth cracks using SS-OCT images, and to automatically detect the position of various cracks in the OCT images. Therefore, the detection capability of SS-OCT images provides a useful diagnostic tool for cracked tooth syndrome.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.761-765
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• 1995

The old Timing Controller for Control Element Drive Mechanism (CEDM) is designed as an open loop control system because it is difficult to mount sensors within the Control Element Drive Mechanism(CEDM) which is operating under the pressure boundary of the reactor vessel. In this work new method which can be used to detect the CEDM operational conditions without mounting sensors within the CEDM housing is developed in order to resolve problems of the old Timing Controller. By using the developed new method, the new Timing Controller for the CEDM is designed as a closed loop controller which has features of the control rod drop prevention, fine position control and the coil life time extension. The algorithm developed under closed loop control concept resolves most problems occurred in the old Timing Controller and improves the performance and reliability of the system. During designing and testing of the Timing Controller algorithm, the real time CEDM simulator developed here was used. And all functions of the developed algorithm were verified using CEDM simulator with the real data collected from the site. The results show that the Timing Controller performs its intended functions properly.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.2
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• pp.211-217
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• 2009

This paper proposes a way of expanding the use area of localization technique by using a beacon. In other words, we have developed the auto-calibration algorithm that recognizes the location of this beacon by attaching the beacon on an arbitrary position and by using the information of existing beacon under this situation. By doing so, the moving robot can overcome the limitation that the localization of moving robot is only possible within the area that has installed the existing beacon since the beacon cannot be installed on the accurate location when passing through a danger zone or an unknown zone. Accordingly, the moving robot can slowly move to the unknown zone according to this auto-calibration algorithm and can recognize its own location at a later time in a safe zone. The localization technique is essentially needed in using a moving robot and it is necessary to guarantee certain degree of reliability. Generally, moving robots are designed in a way to work well under the situation that the surroundings is well arranged and the localization techniques of using camera, laser and beacon are well developed. However due to the characteristics of sensor, there may be the cases that the place is dark, interfering radio waves, and/or difficult to install a beacon. The effectiveness of the method proposed in this paper has been proved through an experiment in this paper.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.2
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• pp.106-114
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• 2017

In this paper, we propose the method of designing an extended kalman filter in order to accurately measure the position of the spatial-phase system using sensor fusion. We use the quaternion as a state variable in expressing the attitude of an object. Then, the attitude of rigid body can be calculated from the accelerometer and magnetometer by applying the Gauss-Newton method. We estimate the changes of state by using the measurements obtained from the gyroscope, the quaternion, and the vision informations by ARVR_SDK. To increase the accuracy of estimation, we designed and implemented the extended kalman filter, which showed excellent ability to adjust and compensate the sensor error. As a result, we could experimentally demonstrate that the reliability of the attitude estimation value can be significantly increased.

• Human Ecology Research
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• v.51 no.3
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• pp.293-306
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• 2013

The aim of this study is to examine the effects of the story sharing activity on-conflicting situations by the use of children's story on the theory of mind and peer competences of preschoolers so that appropriate teaching materials can be allocated for the actual preschool education site. The subjects of this study were 46 preschoolers under the age 4 at the attached kindergarten of P University in Pohang City, Gyeongbuk and in which 23 children among them were assigned to a test group and the other 23 to a control group. The collected data was analyzed by SPSS ver. 15.0 program and Cronbach's ${\alpha}$ coefficient was yielded to verify the reliability for each scale. The multivariate analysis of covariance (MANCOVA) was conducted. The analysis results are as follows. First, the story sharing activity on conflict situations by using children's story had a significant effect on the preschoolers' general appearance and actual task as sub-factors of the theory of mind, whereas no significant effects were found regarding the content change task and position change task. Second, the story sharing activity on conflict situations by using children's story had significant effect on the preschoolers' overall sensitivity, insecurity and pro-sociability as sub-factors of the peer competences, whereas no significant effects were found regarding the aggression, exclusivity and anti-sociability.