• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.11
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• pp.71-78
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• 1995

Based on the popular 4-transistor SRAM cell, an analytical expression of the minimum cell ratio was derived by modeling the static read operation. By analyzing the relatively simple expression for the minimum cell ratio, which was derived assuming the ideal transistor characteristics, effects of the changes in supply voltage and process parameters on the minimum cell ratio was predicted, and the minimum power supply voltage for read operation was determined. The results were verified by simulations utilizing the suggested simulation method, which is suitable for monitoring the lower limit of supply voltage for proper cell operation. From the analysis, it was shown that the worst condition for cell operation is low temperature and low supply voltage, and that the operation margin can be effectively improved by reducing the threshold voltage of the cell transistors.

• The Korean Journal of Health Service Management
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• v.11 no.3
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• pp.1-11
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• 2017

Objectives : The purpose of this study was to analyze factors affecting the performance of public hospitals in South Korea. Methods : We collected management performance data from 2013 to 2015 from income statements, balance sheets, and annual reports from 32 local public hospitals. The dependent variable used was profitability, which included operating margin, return on assets and net profit to gross revenues. The independent variables were general characteristics, liquidity, stability, and activity. Results : Patient revenues, total assets, and total capital had increased steadily but patient expenses had increased to a greater extent. Operating profit, and net profit were consistently in deficits and the management status of local public hospitals had recently been in difficulty. The debt ratio, quick ratio, ratio of fixed liability and fixed assets turnover rate have a significant positive(+) effect on performance in the years 2013-2015. Conclusions : We suggest management strategies for these hospitals based on the results analyzed.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.43-48
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• 2001

Combustor design technique is established by reverse engineering of existing combustor and applying heat & mass balance equations for the combustion process. The ratio of entrained air for each air slot is found to be almost proportional to the area ratio from the result of numerical simulation. The shape of the combustor is modified by the numerical analysis to get circumferentially uniform flow inside the combustion chamber required for the flame stability.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10a
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• pp.258-261
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• 1998

Aggregate is cheaper than cement and confers considerable technical advantages on concrete, which has a higher volume stability and better durability than hydrated cement paste alone. and coarse aggregate is the largest particle size out of concrete and is much affect on the fruidity, compaction and non-segregation ability of high flowing concrete. As the compaction, fillingability and shrinkage of high flowing concrete, the volume ratio of coarse aggregate is prescribed by Japanese Architectural Standard Specificateon (JASS 5) : from 0.500 to 0.500㎥/㎥. It is the aim of this study to compare and analysis the fruidity, fillingability and non-segregation of high flosing concrete according to the volume ratio of coarse aggregate of concrete(G/Glim).

• Transactions on Electrical and Electronic Materials
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• v.15 no.6
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• pp.348-352
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• 2014

In light of the sure protection function, the most important factors of a varistor are the clamping voltage ratio and degradation characteristics. The degradation characteristics of Pr/Co/Cr/Er co-doped zinc oxide varistors were investigated by impulse currents (0.4~2.1 kA) stress for the specified content of $Er_2O_3$ (0.5 and 2.0 mol%). The varistor doped with 2.0 mol% $Er_2O_3$ exhibited the best clamp characteristics, with the clamp voltage ratio (K) in the range of K = 1.63~1.88 at the impulse currents of 5-50 A. However, the varistor doped with 0.5 mol% exhibited excellent electrical stability, with variation rates for the breakdown field, for the nonlinear coefficient, and for the leakage current density of -6.9%, -12.6%, and -14.3%, respectively, after application of an impulse current of 2.1 kA. In contrast, the varistor doped with 2.0 mol% was destroyed after application of an impulse current of 1.2 kA.

• Journal of the Korean Society of Combustion
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• v.4 no.2
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• pp.35-41
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• 1999

The purpose of this study is to establish the flame structure and NOx emission characteristics of the swirl flow coaxial diffusion combustion in the model gas turbine combustor. The mean temperature, ion currents and NOx emission measurement technique showed the effect of equivalence ratio into flame length and flame stability. As a result of this study, NOx emission was increased by increasing the equivalence ratio, and the peak value of the NOx was appeared near the flame front.

• The Journal of the Korean dental association
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• v.56 no.9
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• pp.503-511
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• 2018

Outcome of esthetic ceramic restorations are affected by tooth size, gingival contour, occlusal relationship, etc. For this reason, demand of orthodontic treatment before esthetic ceramic restoration is increasing. If a Bolton ratio discrepancy, a problem of the maxillary incisor's vertical position, a problem of inclination of anterior teeth, a pathogenic occlusion is existed, a pre-prosthodontic orthodontics should be accomplished. These problems can be satisfactory only after the prosthetic treatment is performed after orthodontic treatment. When orthodontic treatment is given, it should be treated with the following principle. 1. Treat it in the direction of functioning occlusion. 2. Keep the patient's stable occlusal scheme. 3. Treat the teeth by considering the average tooth size and Bolton ratio. Ortho-Prostho combined treatment with optimal treatment plan can lead a patient's function, esthetics, and long-term stability.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.3-14
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• 2000

Anisotropic consolidation, shear, a transportational component during or after deposition each may produce anisotropic fabrics, which result in the anisotropic properties of soils. Nevertheless, the isotropically consolidated compression triaxial tests are commonly used in practice to determine the strength of the anisotropically consolidated soils because of their practicality and simplicity. In this paper the effects of anisotropic consolidation on the strength properties of soils are discussed. For the sandy soils consolidated under a constant vertical consolidation pressure, the deformation modulus decreases with decreasing consolidation pressure ratio($\sigma$$\sub$3c/'/$\sigma$ sub 1c/'), but the liquefaction resistance increases. For the saturated cohesive soils, both the undrained shear strength and undrained creep strength decrese with decreasing the consolidation pressure ratio. When the in-situ strength properties of the anisotropically and normally consolidated soils are determined by the isotropically consolidated tests, the undrained shear strength and creep strength of saturated cohesive soils as well as the deformation modulus of sandy soils are measured to be higher than the rear in-situ values. This, therefore, could lead to a dangerous judgement in stability analysis

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.4
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• pp.13-21
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• 2007

This paper presents characteristics of steady flow by variation of a combustion chamber and an intake port. Gas flow field inside a combustion chamber is the important factor in improving combustion stability and reduction of emission level. The flow characteristics such as flow coefficient, tumble ratio and swirl ratio are measured by the steady flow rig test with an impulse meter in this study. In the measuring, the valve lifts are varied between 1mm to 10mm. The three combustion chambers and two intake ports were applied to the steady flow apparatus in order to investigate the effect of swirl and tumble on the in-cylinder flow. As a result, tumble ratio were found to be different by variation of the combustion chambers and the intake ports. The data from the present study can be applied to design of a similar engine as basic data.

• Structural Engineering and Mechanics
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• v.18 no.6
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• pp.745-757
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• 2004

Lateral-torsional buckling moment resistances of I-shaped stepped beams with continuous lateral top-flange bracing under a single point load on the top flange and negative end moments were investigated. Stepped beam factors and a moment gradient correction factor suggested by Park et al. (2003, 2004) were used to develop new lateral buckling formula for beam designs. From the investigation of finite element analysis (FEA), new lateral buckling formula of beams with singly or doubly stepped member changes and with continuous lateral top-flange bracing subjected to a single point load on top flange and end moments were developed. The new design equation includes the length-to-height ratio factor to account for the increase of lateral-torsional buckling moment resistance as the increase of length-to-height ratio of stepped beams. The calculation examples for obtaining lateral-torsional buckling moment resistance using the new design equation indicate that engineers should easily determine the buckling capacity of the stepped beams.