• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.165-170
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• 1997

In this paper, we consider the aortic sinus baroreceptor, which is the most representative baroreceptors sensing the variance of pressure in the cardiovascular system(CVS), and propose heart activity control model to observe the effect of delay time in heart period and stroke volume under the regulation of baroreflex in arotic sinus. The proposed heart activity baroreflex regulation model contains CVS electric circuit sub-model, baroreflex regulation sub-model and time delay sub-model. In these models, applied electric circuit sub-model is researched by B.C.Choi and the baroreflex regulation sub-model transforms the input, the arotic pressure of CVS electric circuit sub-model, to outputs, heart period and stroke volume by mathematical nonlinear feedback. We constituted the time delay sub-model to observe sensitivity of heart activity baroreflex regulation model by using the variable value to represent the control signal transmission time from the output of baroreflex regulation model to efferent nerve through central nervous system. The simulation object of this model is to observe variability of the CVS by variable value in time delay sub-model. As simulation results, we observe three patterns of CVS variability by the time delay. First, if the time delay is over 2.5 sec, arotic pressure, stroke volume and heart rate is observed nonperiodically and irregularly. Second, if the time delay is from between 0.1 sec and 0.25 sec, the regular oscillation is observed. Finally, if time delay is under 0.1 sec, then heart rate and arotic pressure-heart rate trajectory is maintained in stable state.

• Journal of Korean Academy of Nursing
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• v.20 no.3
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• pp.300-306
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• 1990

Colorectal cancer is second only to lung cancer as a cause of death due to cancer in the united States. Studies have shown that fecal occult blood(FOB) tests are effective in detecting colorectal cancer in its early stages. To motivate worksite FOB testing, a randomized controlled trial was conducted. Employees 40 years or older from three federal agencies in Washington State were randomized to a control group(n＝139) which received a letter stating the availability of the FOB test at the worksite clinic or to an intervention group(n＝139) which received the letter about facts on colorectal cancer and a Colorectal Cancer Risk Appraisal. The Colorectal Cancer Risk Appraisal included a feedback on an individual's risk of developing colorectal cancer compared to his / her peers in terms of ‘normal’, ‘moderate’, or ‘high’ risk status. After 3 months, a follow-up questionnaire was sent to all participants to measure the effectiveness of the intervention. In the analysis of the three major outcomes, two possible confounding factors(dietary fat and family history of colorectal cancer) were controlled by logistic regression. Based on a review of the worksite clinic records, the Intervention group had 4.3% higher compliance rate with the FOB test during the follow-up period compared to the control group(p＝.10). The largest effect of the intervention was on the employees' intention to get a FOB test within the next year(62.6% in the intervention group vs. 36.2% in the control group, OR＝3.18, p＜.001). In the final Multivariate logistic model, the employees who were more likely to intend to get a FOB test within the next year were in the intervention group ; were at ‘moderate’ or ‘high’ risk of colorectal cancer ; knew more about the availability of the FOB test at the worksite clinic ; and had a FOB test during the last three years.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6B
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• pp.575-583
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• 2004

In this paper, we extend the multiple time scale control framework to the window-based congestion control, in particular, such as the TCP. This is performed by interfacing the TCP with a large time scale control module which adjusts the aggressiveness of the bandwidth consumption behavior exhibited by the TCP as a function of large time scale Self-Similar network state. i.e., conformation that exceeds the horizon of the feedback loop as determined by the RTT. How to effectively utilize such an information-due to its probabilistic nature, dispersion over the multiple time scales, and affection on the top of the existing window-based congestion controls-is a non-trivial problem. The evaluation performance of the multiple time scale TCP is facilitated by a simulation of the bench-mark environment which is based on the physical modeling of a self-similar traffic. We explicate our methodology for discerning and evaluating the impact of changes in transport protocols in the protocol stack under the self-similar traffic conditions. We discuss issues arising in the comparative performance evaluation under heavy-tailed workloads.

• Proceedings of the Korean Society of Computational and Applied Mathematics Conference
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• 2003.09a
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• pp.1-1
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• 2003

In this talk, a reduced-order modeling methodology based on centroidal Voronoi tessellations (CVT's)is introduced. CVT's are special Voronoi tessellations for which the generators of the Voronoi diagram are also the centers of mass (means) of the corresponding Voronoi cells. The discrete data sets, CVT's are closely related to the h-means clustering techniques. Even with the use of good mesh generators, discretization schemes, and solution algorithms, the computational simulation of complex, turbulent, or chaotic systems still remains a formidable endeavor. For example, typical finite element codes may require many thousands of degrees of freedom for the accurate simulation of fluid flows. The situation is even worse for optimization problems for which multiple solutions of the complex state system are usually required or in feedback control problems for which real-time solutions of the complex state system are needed. There hava been many studies devoted to the development, testing, and use of reduced-order models for complex systems such as unsteady fluid flows. The types of reduced-ordered models that we study are those attempt to determine accurate approximate solutions of a complex system using very few degrees of freedom. To do so, such models have to use basis functions that are in some way intimately connected to the problem being approximated. Once a very low-dimensional reduced basis has been determined, one can employ it to solve the complex system by applying, e.g., a Galerkin method. In general, reduced bases are globally supported so that the discrete systems are dense; however, if the reduced basis is of very low dimension, one does not care about the lack of sparsity in the discrete system. A discussion of reduced-ordering modeling for complex systems such as fluid flows is given to provide a context for the application of reduced-order bases. Then, detailed descriptions of CVT-based reduced-order bases and how they can be constructed of complex systems are given. Subsequently, some concrete incompressible flow examples are used to illustrate the construction and use of CVT-based reduced-order bases. The CVT-based reduced-order modeling methodology is shown to be effective for these examples and is also shown to be inexpensive to apply compared to other reduced-order methods.

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.522-534
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• 2019

The purpose of this study is to investigate the interaction factors(learning motivation, concrete feedback, learner's control) and affordance factors (aesthetics, playfulness, stability) that influence flow in e - learning. This study collected 236 survey data from e-learning users. The data was analyzed the statistical relationships among the variables using the SPSS21 and AMOS21. The measurement model was reliable and valid, and the structual model was good. The result shows that interaction factors (concrete feedback, learner's control) and affordance factor (playfulness) influence on flow. Flow has a significant effect on satisfaction. Especially the effect of playfulness on flow is meaningful. Playfulness is one of the most important factors leading to the flow state of humans. The contribution of this study is to find the factors influencing flow in the interaction between learners and computer in e-learning. It can be used to provide an entertainment experience that can enhance the satisfaction of consumers in the Internet environment by finding the antecedents that affect the flow in computer - human interaction.

• Annals of Pediatric Endocrinology and Metabolism
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• v.23 no.4
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• pp.204-209
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• 2018

Purpose: Growth hormone transduction defect (GHTD) is characterized by severe short stature, impaired STAT3 (signal transducer and activator of transcription-3) phosphorylation and overexpression of the cytokine inducible SH2 containing protein (CIS) and p21/CIP1/WAF1. To investigate the role of p21/CIP1/WAF1 in the negative regulation of the growth hormone (GH)/GH receptor and Epidermal Growth Factor (EGF)/EGF Receptor pathways in GHTD. Methods: Fibroblast cultures were developed from gingival biopsies of 1 GHTD patient and 1 control. The protein expression and the cellular localization of p21/CIP1/WAF1 was studied by Western immunoblotting and immunofluorescence, respectively: at the basal state and after induction with $200-{\mu}g/L$ human GH (hGH) (GH200), either with or without siRNA CIS (siCIS); at the basal state and after inductions with $200-{\mu}g/L$ hGH (GH200), $1,000-{\mu}g/L$ hGH (GH1000) or 50-ng/mL EGF. Results: After GH200/siCIS, the protein expression and nuclear localization of p21 were reduced in the patient. After successful induction of GH signaling (control, GH200; patient, GH1000), the protein expression and nuclear localization of p21 were reduced. After induction with EGF, p21 translocated to the cytoplasm in the control, whereas in the GHTD patient it remained located in the nucleus. Conclusion: In the GHTD fibroblasts, when CIS is reduced, either after siCIS or after a higher dose of hGH (GH1000), p21's antiproliferative effect (nuclear localization) is also reduced and GH signaling is activated. There also appears to be a positive relationship between the 2 inhibitors of GH signaling, CIS and p21. Finally, in GHTD, p21 seems to participate in the regulation of both the GH and EGF/EGFR pathways, depending upon its cellular location.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.3
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• pp.99-108
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• 2003

This paper is concerned with the problem of designing a guaranteed cost state feedback controller for singular systems with time-varying delays. The sufficient condition for the existence of guaranteed cost controller, the controller design method, and the optimization problem to get the upper bound of guaranteed cost function are proposed by LMI(linear matrix inequality), singular value decomposition, Schur complements, and change of variables. Since the obtained sufficient conditions can be changed to LMI form, all solutions including controller gain and the upper bound of guaranteed cost function can be obtained simultaneously. Moreover, the proposed controller design method can be extended to the problem of robust guaranteed cost controller design method for singular systems with parameter uncertainties and time-varying delays. The validity of the proposed design algorithm is investigated through a numerical example.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.45-51
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• 2009

In this paper, a transparency analysis and network-adaptive transport scheme are proposed in order to improve transparency of EBA-based force-reflecting teleoperation. EBA guarantees stability of force-reflecting teleoperation over network delay and loss but has limitation that it cannot overcome transparency deterioration of haptic interactions. The proposed transparency analysis quantifies the force feedback distortion caused by network delay and loss. Based on the analysis, the proposed haptic data synchronization and transmission rate control schemes adapt synchronization delay and transmission rate to current network state for more transparent haptic interaction. Through Matlab/Simulink simulations, it is confirmed that the proposed analysis provides an acceptable quantification method about haptic interaction quality and that the proposed haptic data transport scheme effectively improves haptic interaction quality with respect to network delays and losses.

• Korean Institute of Interior Design Journal
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• v.25 no.5
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• pp.42-54
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• 2016

The purpose of this study is to provide a reference for stage planning by analyzing current state of major theaters' stage space and understanding feedback from directors belonged to theaters. Each room in total 18 theaters' stage facilities was measured and their usage and requirements were analyzed on the spot. In addition, each director provided their experiential knowledge about appropriate stage composition for musical performance. The findings are as follow: under stage machinery is not needed for musical. Tour teams prefer to use their own show-deck for set conversion. On the other hand, over stage flying system needs to be able to deal with dense, fast, and accurate scene change. The size and location of the motor room needs to be carefully considered. The number of set battens is directly linked up with the size of the motor room, which should be located lower than the gridiron. As stage sets get bigger and complicated, the number of works at the gridiron is also increasing. The grating floor has to have enough strength coping with machines lifting heavy sets. Most sound control for musical performance is being done at F.O.H. these days rather that in the sound control room. It should equip enough work area and related infra especially for tour teams. 1st gallery needs to have enough effective width, power infra for lighting fixture, and strong guardrail. Lastly, the whole process of parking-unloading-transporting equipments and sets from loading dock to stage and vice versa needs to be efficient, and this has to be carefully considered from early stage of planning.

• Clinical and Experimental Pediatrics
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• v.55 no.9
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• pp.337-343
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• 2012

Purpose: Leptin has been considered a link between metabolic state and reproductive activity. Defective reproductive function can occur in leptin-deficient and leptin-excessive conditions. The aim of this study was to examine the effects of centrally injected leptin on the hypothalamic KiSS-1 system in relation to gonadotropin-releasing hormone (GnRH) action in the initial stage of puberty. Methods: Leptin (1 ${\mu}g$) was injected directly into the ventricle of pubertal female mice. The resultant gene expressions of hypothalamic GnRH and KiSS-1 and pituitary LH, 2 and 4 hours after injection, were compared with those of saline-injected control mice. The changes in the gene expressions after blocking the GnRH action were also analyzed. Results: The basal expression levels of KiSS-1, GnRH, and LH were significantly higher in the pubertal mice than in the prepubertal mice. The 1-${\mu}g$ leptin dose significantly decreased the mRNA expression levels of KiSS-1, GnRH, and LH in the pubertal mice. A GnRH antagonist significantly increased the KiSS-1 and GnRH mRNA expression levels, and the additional leptin injection decreased the gene expression levels compared with those in the control group. Conclusion: The excess leptin might have suppressed the central reproductive axis in the pubertal mice by inhibiting the KiSS-1 expression, and this mechanism is independent of the GnRH-LH-estradiol feedback loop.