• Korean Journal of Optics and Photonics
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• v.29 no.6
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• pp.241-246
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• 2018

In this paper, a low-cost optical temperature sensor is implemented, using a fiber Bragg grating (FBG) as the temperature probe and a low-cost VCSEL with temperature-dependent output wavelength as the light source. To analyze the wavelength of the reflected light from the FBG, an interrogation was applied using a method of referring to the internal temperature according to the output wavelength of the VCSEL. When the temperature of the VCSEL was adjusted from 14 to $52.2^{\circ}C$, the output wavelength varied from 1519.90 to 1524.25 nm. The degree of wavelength tuning according to temperature was $0.114nm/^{\circ}C$. The variable wavelength repeatability error according to temperature was ${\pm}0.003nm$, and the temperature measurement error was ${\pm}0.18^{\circ}C$. As a result of measuring the temperatures from 22.3 to $194.2^{\circ}C$, the value of the internal temperature change of the light source according to the applied temperature ${\Delta}T$ was $0.146^{\circ}C/{\Delta}T$, the change in reflected wavelength of the temperature probe according to applied temperature ${\Delta}T$ was measured at $16.64pm/^{\circ}C$. and the temperature measurement error of the sensor was ${\pm}1^{\circ}C$.

• 사회경제평론
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• no.38
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• pp.199-240
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• 2012

According to the Post Keynesian endogenous money theory, money is created by the bank deposit which is dependent on the banks' supply of loan. And the demand for loans is dependent on investment by firms. In the money creating process, real value(or investment) and money are connected with banks' credit. In this paper, we investigated Keynes and Post Keynesian endogenous money theory with critical reviews of Hwang (2005). We came to three conclusions. First, Post Keynesian endogenous money theory is based on Keynes' theory. Second, Keynes' endogeneity of money is essentially different from that of Wicksellian. Third, focusing on the differences of the starting point of the arguments not on the conclusions, two Post Keynesian views, namely horizontalists and structuralists are compatible with liquidity preference theory in the Keynes' system.