• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.108-111
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• 2016

We propose the method for measuring sensitivity of optical receiver of a long-range laser range finder in real-time. The sensitivity of the detector can be calculated using the detected voltage of the reference sensor, the area of the reference sensor and the transmittance ratio of neutral density filters. To evaluate the performance of the proposed method, we implemented a system and performed experiments. As a result, this system can be measured from 2nW to $113{\mu}W$. With this system, we measured the sensitivity of 37nW and 7nW with PIN PD and APD sample, respectively. This system has the advantage for the performance test of an optical sensor module in the long-range laser range finder.

• Journal of KSNVE
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• v.6 no.4
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• pp.475-479
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• 1996

Recently, fiber optic hydrophone is a subject which has attracted as a underwater acoustic sensor. In this paper, a length of optical fiber is bonded to an end-capped hollow cylinder of some elastic material, e. g. aluminum and glass-pyres. The normalized sensitivity is derived according to the direction of polarization. Derived sensitivity equations are simulated for two different mandrel materials. The results are also compared to the McMahon's results which calculated for an average Pockel coefficient. Based on the numerical simulation normalized sensitivity is propotional to the inner to outer diameter ratio.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.453-454
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• 2007

This paper proposes the calculation method of voltage sensitivity index using CBEMA power acceptability curves and the voltage curves of the load bus to which momentary events occur. Voltage sensitivity index is represented by areas between two curves. Voltage sensitivity index is a parameter that depicts the ratio of a load disruption. The correlation between the installation cost of compensation devices and the voltage sag index on the bus can be used the validity of compensation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1654-1662
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• 2011

This paper investigates how does cash holdings have effect on investment-cash flow sensitivity in korea firms over the period 1981-2009. According to $\"{O}$.Arslan et al.(2006), I expect that financially constrained firms have more cash holdings. and financially constrained cash-rich firms are likely to have less investment-cash flow sensitivity especially in the financial crisis period. Using financial constraint classification variables(firm size, dividend, cash holdings), we divide whole sample firms into financially constrained firms and financially unconstrained firms, and then I compare investment-cash flow sensitivity in pre-financial crisis(1981-1996), financial crisis(1997-1998) and after-financial crisis(1999-2009) period. This paper's findings are as follows: First, under no financial constraint classification conditions, cash-poor firms exhibit greater investment-cash flow sensitivity than cash-rich firms do during 1981-2009 period except financial crisis period. These findings support the hypothesis that firms have more cash holdings less investment-cash flow sensitivity except in financial crisis period. In financial crisis period, cash holdings have no effect on investment-cash flow sensitivity. Second, this paper findings are somewhat different as $\"{O}$.Arslan et al.(2006)'s. Under the financial constraint classification conditions, financially unconstrained firms have more investment-cash flow sensitivity rather than constrained firms have. The reason is that both dividend and firm size are not a complete classification criteria variables. And there exists other possible determinants of investment-cash flow sensitivity. Finally, this paper find that there are common determinants of corporate cash holdings in all periods. This paper suggests that cash flow and market to book ratio are positive determinants of corporate cash holdings but short-term debt, investment and firm size are negative determinants of corporate cash holdings.

• The Journal of Fisheries Business Administration
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• v.43 no.3
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• pp.31-41
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• 2012

This paper was conducted to study the economic valuation for Nursery-Phase production of the tidal flat oyster in Korea. Benefit-cost(B/C) model used to indicate the effects of economic valuation. Using discounting rates(i.e., 4.5%, 6.5% and 8.5%), the model compared revenues and costs that occur at different times from 2012 to 2018. This study also estimated various submodels, which are Benefit Cost Ratio(B/C ratio), Net Present Value(NPV), Internal Ration of Return(IRR), to compare profit of Nursery-Phase production styles and analyzed returns to evaluate the scenarios. Sensitivity analysis were conducted for various scenarios. The results suggest as follows. First, the oyster spat to the shell height of 3~5cm was more profit than the shell height of 1~3cm. Second, all of sensitivity analysis with submodels were economic valuation such that B/C ratio > 1, NPV > 0 and IRR > discounting rate. Third, the payback period was about 3years after installed Nursery-Phase production system.

• The Korean Journal of Applied Statistics
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• v.26 no.1
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• pp.15-22
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• 2013

In clinical study or epidemic research, the $2{\times}2$ frequency table is useful to present a summary statistic The values of four cells in $2{\times}2$ table use to calculate the effect measures such as risk ratio, relative ris ratio or odds ratio. In this paper, we suggest that the improved visualization method using a radar diagram supported by MS-office Excel from the $2{\times}2$ frequency table is able to understand and draw easily betweendiagnosti measures such as sensitivity, specificity, predictivity, and likelihood ratio. We use some numerical example in order to show the usage of the proposed method.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.1
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• pp.75-81
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• 1998

This paper is to optimize single-element piezoresistor shear stress strain gauge related to aspect ratio of rectangular diaphragm. The shear stress distribution on diaphragm has been simulated by finite-element method(FEM). As simulation results, the maximum sensitivity for strain gauge was appeared at the center of diaphragm with aspect ratio 3, and in along to long edge with the ratio 2. The diaphragm with ratio 2 is not acceptable due to the yield of mask alignment in IC process technology. The optimum condition of diaphragm with respect to good sensitivity was realized in the case of ratio 3. In this case, the area by gauge was 8% of overall size of rectangular diaphragm.

• Journal of Ocean Engineering and Technology
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• v.2 no.2
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• pp.122-129
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• 1988

Recently with the rapid development in marine and shipbuliding industries such as marine structures, ship and chemical plants, there occurs much interest in the study of corrosion fatigue characteristics which was closed up an important role in mechanical design. In this study, the 5086 Al-alloy was tested by use of rotary bending fatigue tester. The retardation effect of overload on the corrosion fatigue crack propagation in sea environment was quantitatively studied. 1) Retardation effect of corrosion fatigue crack propagation is most eminent when overload ratio is 1.52, overload magnitude corresponds to about 77% and 55% of yield strength and tensile strength respectively. 2) After overload ratio 1.52 was used, retardation of corrosion fatigue crack growth rate is largely retarded and quasi-threshold stress intensity factor range($\Delta\textrm{K}_{th}$) appears. 3) According to m of experimental constant, retardation effect of corrosion fatigue crack propagation corresponds to about 25% of constant stress amplitude when overload ratio is 1.52. 4) When overload ratio 1.52 was used, retardation parameter (RP) decreases to about 0.43 and corrosion sensitivity (S)decreses to about 2.1.

• Journal of Nutrition and Health
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• v.33 no.8
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• pp.864-872
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• 2000

This study intended to evaluate the validity of the simple nutrition screening test that had been developed with the elderly living in Cheongju as a subject. Nutrition screening score(NSS) and reference standards for nutritional and health status(nutrient intakes, mean adequacy ratio, perceive health, and serum albumin, hematocrit, and hemoglobin) were estimated by using the date obtained in 1996 from the 174 elderly living in Taejon, Statistical analysis showed significant correlations between mean adequacy ratio(MAR) and NSS(r=0.341) and also between NSS and biological indices such as albumin and hematocrit, Around 65-75% of the elderly with perceive health and low level of serum albumin, hemoglobin and hematocrit had NSS$\leq$ll. Sensitivity, specificity, and positive predictive values(PPV) were calculated from the crosstabulation of the three categories of NSS(high, moderate, and low nutritional risk) and low categories MAR(< 0.75, undernutrition;$\geq$0.75, normal) to validate the cut-off point for high or low nutritional risk by NSS. It was suggested that point l1 was appropriate as a criterion to determine high risk of undernutrition, but point 16 was better than 17 as criterion to determine low nutritional risk in the Taejon elderly. When point ll was used as a criterion of high nutritional risk, sensitivity, specificity, and PPV are 59.5, 60.5 and 82.1 respectively. When point 16 was used as a criterion of low nutritional risk, sensitivity, specificity, and PPV are 25.6, 95.4, and 64.7%, respectively. In conclusion, nutrition screening test that had been developed can be a simple, easy, and proper instrument to classify the high risk group of undernutrition. A further validation study seems to be required among other groups of individuals for the screening test to the finalized as a more valid instrument identifying Korean elderly at nutrition and health risk(Korean J Nutrition 33(8) : 864-872, 2000)

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.133.2-133.2
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• 2005