• The Korean Journal of Physiology
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• v.23 no.2
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• pp.377-391
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• 1989

Recently it was suggested that the endogenous adenosine might be the mediator for the intercellular communication in the regulation of tubuloglomerular feedback control and renin release. Even though the previous data showed more important regulatory roles in the renal hemodynamics and renin release for the A1 adenosine receptor, it has not yet been settled down about the functional subclassification of renal adenosine receptors. The purpose of the present experiment was to clarify the importance of the renal adenosine receptors for the regulations of the hemodynamic, excretory and secretory functions. Experiments have been done in unanesthetized rabbits. Intrarenal arterial infusion of A1 adenosine antagonist, 8-phenyltheophylline, $3{\sim}30\;nmole/min$, increased urine flow, renal hemodynamics and urinary excretion of sodium. Intrarenal arterial infusion of Al antagonist, 1-3-diethyl-8-phenylxanthine (DPX), $10{\sim}100\;nmole/min$, increased renal hemodynamics and excretory functions. Non-specific adenosine antagonist, theophylline, $30{\sim}300\;nmole/min$, resulted in dose dependent increases in renal hemodynamics and excretory function. All of the three adenosine antagonists for the increases in renal hemodynamics, excretory and secretory functions was 8-phenyltheophylline > DPX > theophylline. These results suggest that the endogenous adenosine is important for the intrinsic regulatory roles for the renal functions through the adenosine receptors, and that the A1 adenosine receptor is more important than the A2 receptor in the regulation of renal hemodynamics, excretory and renin secretory functions.

• Journal of Korean Home Economics Education Association
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• v.30 no.2
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• pp.117-136
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• 2018

The purpose of this study is restructuring the template to apply the 'Backward design' for Home Economics Instruction. This study reviewed the theory of Wiggins and McTighe, the advocates of backward design, and examined the template for version 2.0 of Wiggins and McTighe (2011). In addition, This study analyzed various previous researches using backward design, and drew implications for template restructuring for applying backward design on Home Economics Instruction. In addition, the validity of the template was verified through facial validity through the expert council. Through this process, the final 5 stages (1. Curriculum Analysis → 2. Instructional Design (Learning Experience Design ↔ Evaluation Design (Performance Task Planning) → 3. Instruction Flow → 4. Class guide for each class → 5. Evaluation record, and feedback)suggested templates for applying backward design. Future research will use the restructured assumptions and templates to develop teaching materials in the Home Economics areas of the 2015 revised curriculum. In future research, field research should be carried out on how the Home Economics instruction with backward design affects learners.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.2
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• pp.39-46
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• 2012

The newly designed sense amplifier in this paper has rail-to-rail input range achieving low power consumption. Reducing static power consumption generated due to DC path to ground is key element for low power consumption in this paper. The proposed sense amplifier performs power-saving operation using negative feedback circuit that controls the current flow with the newly added PMOS input terminal. As a simulation result, the proposed sense amplifier consumed about over 50 % efficiency of the average power consumed by the typical Rail-to-Rail sense amplifier.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.5 no.1 s.9
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• pp.55-63
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• 2006

Speeding is one of the major causes of traffic accidnets in urban areas. Driver feedback sign(DFS) is a traffic control device that can be used for many traffic environments including work zones, school zones, and roadways. In this paper, the effectiveness of DFS was evaluated through a field study using speed data collected from before and after study periods. In addition traffic safety improvement was also quantitatively estimated using the variance of speed data collected. Staistical test results showed that the speed difference was statistically significant, and the distribution of speed data was also shifted greatly. Therefore, it was concluded that installing the DFS in roadways might lead to unifomity of speed of traffic flow, thus, potential safety improvement might be expected.

• Journal of The Korean Astronomical Society
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• v.35 no.4
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• pp.159-174
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• 2002

Cosmological hydrodynamic simulations of large scale structure in the universe have shown that accretion shocks and merger shocks form due to flow motions associated with the gravitational collapse of nonlinear structures. Estimated speed and curvature radius of these shocks could be as large as a few 1000 km/s and several Mpc, respectively. According to the diffusive shock acceleration theory, populations of cosmic-ray particles can be injected and accelerated to very high energy by astrophysical shocks in tenuous plasmas. In order to explore the cosmic ray acceleration at the cosmic shocks, we have performed nonlinear numerical simulations of cosmic ray (CR) modified shocks with the newly developed CRASH (Cosmic Ray Amr SHock) numerical code. We adopted the Bohm diffusion model for CRs, based on the hypothesis that strong Alfven waves are self-generated by streaming CRs. The shock formation simulation includes a plasma-physics-based 'injection' model that transfers a small proportion of the thermal proton flux through the shock into low energy CRs for acceleration there. We found that, for strong accretion shocks, CRs can absorb most of shock kinetic energy and the accretion shock speed is reduced up to $20\%$, compared to pure gas dynamic shocks. For merger shocks with small Mach numbers, however, the energy transfer to CRs is only about $10-20\%$ with an associated CR particle fraction of $10^{-3}$. Nonlinear feedback due to the CR pressure is insignificant in the latter shocks. Although detailed results depend on models for the particle diffusion and injection, these calculations show that cosmic shocks in large scale structure could provide acceleration sites of extragalactic cosmic rays of the highest energy.

• 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 Transactions of the Korea Information Processing Society
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• v.7 no.9
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• pp.3002-3010
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• 2000

ATM forum defined several ATM oriented services such as ABR, VBR, CBR, UBR, and others. Among them, ABR service is considered as one of the most appropriate ones in the LAN environment. ABR controls network traffic by using RM cells according to ATM forum standard. In particular, the point-to-multipoint ABR service in general uses consolidation algorithms to solve feedback implosion at the branch point. Consolidation algorithms alleviate propagation delay and network congestion problem: thus, the efficiency of consolidation algorithm is closely related to the network performance. In this paper, we describe the limitation of existing consolidation algorithms based on thorough analysis, and then propose an algorithm that performs better than the existing algorithms. We show that the proposed algorithm improves network performance through a parametric simulation, In our simulation the performance measure is the cell rate which is controlled by exploiting the congestion depth. We also found that the proposed algorithm not only improves efficiency of network, but also eliminates the consolidation noise.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.2
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• pp.72-79
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• 2003

A numerical calculation was conducted to estimate and to elucidate the role of the radiative heat flux from metal particles(Al, $Al_2O_3$) on the dynamic extinction of solid propellant rocket where the rapid depressurization took place. Anon-linear flame modeling implemented by the residence time modeling for metalized propellant was adopted to evaluate conductive heat flux to the propellant surface. The radiative heat feed back was calculated with the aid of a modified comvustion-flow model as well. The calculation results with the propellant of AP:Al:CTPB=76:10:14 had revealed that the radiative heat flux is approximately 5~6% of total flux at the critical depressurization rate regardless of chamber geometry (open or confined chamber). It was also found that the dynamic extinction in open geometry could be predicted at the depressurization rate about 45% larger with radiative heat feedback than without radiation. Thus, it should be claimed that even a small amount of radiative flux 5~6% could produce a big error in predicting the critical depressurization rate of the metalized propellant combustion.

• Journal of Korea Multimedia Society
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• v.13 no.2
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• pp.279-286
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• 2010

Unbalanced traffic load offered to the nodes making up a path in the network guaranteeing quality-of-service has been known as a main cause deteriorating the capability of the path in admitting traffic flows. Several path load balancing methods have been developed to resolve this problem which used a feedback control scheme that adjusts the delay budget of a flow allocated to each node according to the conditions of available resource in the path. Because of no consideration about the probabilistic characteristics of the service quality, it is impossible for them to prevent in advance a bottleneck on the path which leads to a native restriction in the improvement of the capability being deteriorated. This paper proposes a preventive intra-path load balancing method applicable to the RSVP system which is based on the probabilistic characteristics of the quality-of-service of the offered load. The results of the simulation of the proposed method on a simple evaluation network showed that it provides the gain of 4~22% compared to the legacy one in terms of the number of admitted flows.

• The Korean Journal of Physiology
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• v.24 no.1
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• pp.145-159
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• 1990

Recently, it has been suggested that the endogenous adenosine may be the mediator for the intercellular communication in the regulation of tubuloglomerular feedback control and renin release. Even though two subclasses of adenosine receptors, A1 and A2, have been described, their functional roles are controversial. The present study was undertaken to clarify the role of adenosine receptors in hypertensive rabbit caused by clamping of renal artery. Experiments were done in two-kidney one clip Goldblatt hypertensive rabbits (2K1GHR) and sham-operated normotensive rabbits. Adenosine, N6-cyclohexyladenosine (CHA) and 5'-N-ethylcarboxamidoadenosine (NECA) were infused into a renal artery. The decreases in urine volume, renal blood flow, glomerular filtration rate and excreted amounts of electrolytes caused by adenosine and CHA were significantly attenuated in 2K1CHR. However, changes in renal function caused by A2 adenosine receptor agonist, NECA, tend to be accentuated in 2K1CHR. These results suggest that the attenuation of renal effect caused by adenosine and A1 adenosine receptor agonist may be due to the modification of adenosine receptor in the kidney in Goldblatt hypertensive rabbits.