• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.38 no.6
• /
• pp.383-389
• /
• 2001

We report on the design, fabrication, and characterization of 0.35${\mu}{\textrm}{m}$-gate AIGaAs/InGaAs PHEMTs for millimeter-wane applications. The epi-wafer structures were designed using ATLAS for optimum DC and AC characteristics, 0.351m-gate AIGaAs/rnGaAs PHEMTs having different gate widths and number of fingers were fabricated using electron beam lithography Dependence of RF characteristics of PHEMT on gate finger with and number of gate fingers have been investigated. PHEMT haying two 0.35$\times$60${\mu}{\textrm}{m}$$^2$ gate fingers showed the knee voltage, pinch-off voltage, drain saturation current density, and maximum transconductance of 1.2V, -1.5V, 275㎃/mm, and 260.17㎳/mm, respectively. The PHEMT showed fT(equation omitted)(current gain cut-off frequency) of 45㎓ and fmax(maximum oscillation frequency) of 100㎓. S$_{21}$ and MAG of the PHEMT were 3.6dB and 11.15dB, respectively, at 35㎓

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.36D no.8
• /
• pp.27-35
• /
• 1999

A radius of ring resonator is determined by the resonant frequency. Resonant frequencies of resonators with the circumference which is integer times of wave length are not same the expected. In this paper, we suggest the design method of a ring resonator with coupling gap, which has the resonant frequency of desire. The equation which can make reduction of the radius of the resonators depending on the gap space is derived by the method of transmission line analysis. The criterion is suggested to determine the radius of the resonator in accordance with relative permittivity. A ring resonator by the proposed method is as small as one-third of basic ring in size and it has the resonant frequency of desire. T-type coupling line is designed to obtain large attenuation of $S_{11}$ at pass-band. These coupling line capacitances are very lower than the gap capacitances, it does not affect the resonant frequency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.18 no.9
• /
• pp.1023-1029
• /
• 2007

In this paper, we propose the method to solve the BLT equations using Laguerre polynomials in time domain. The solution of BLT equations is obtained by recursive, differential and integral properties of Laguerre polynomials. The verification of the proposed method is tested by applying it to the two-wired transmission line with resistors and capacitors, which is illuminated by the electromagnetic plane wave pulse. And the result is compared with the corresponding transient responses obtained from inverse fast Fourier transform(IFFT) of the frequency domain solutions of BLT equations.

• 전기의세계
• /
• v.14 no.1
• /
• pp.5-12
• /
• 1965

In the designs of the sensitive electronic devices such as phase sensitive detector, X-ray diffractometer, and neutron diffractometers, we must take into account the geometrical factors in a coil systems and extraneous stray fields. Input wave forms in such a sensitive electronic devices are often altered by the influence of these factors. Since the magnitude of the stray fields is generally very small, this affection may be removed by applying a good shielding but it is not ease to remove the affection from a geometrical factor. This affection must be however calculated by the theoretical methods and analytical solution in the equation of these factors. The fundamental purpose of this paper lie in the theoretical calculations and practical measurements of the geometrical factor in the coil systems, finite solenoid, and four point prove. In the heoretical calculations, the geometrical factors in the coil systems were calculated by applying the elliptic functions and in the contact points were calculated by applying the elliptic functions and in the contact points were calculated by applying the eigen functions and the infinite series. The measurements were carried out by using the sensitive electronic device made from author's design, as shown in the Fig. 9. The result of this work has verified the essential correctness of theoretical investigations and measuring techniques of geometrical factors on the design of sensitive electronic devices. It also has several advantages such that: (1) all the data obtained may give effective data to designer to work on the field of sensitive electronic devices or microelectronic devices, (2) it has evidently explained the characteristics of electrical investigations and physical definition, and has removed the conventional error of geometrical factors in the coil systems and contact points.

• Journal of the Korea Institute of Building Construction
• /
• v.20 no.1
• /
• pp.93-102
• /
• 2020

The purpose of this study is to find out how to measure the stress related to accidents at the construction site promptly and conveniently to prevent safety accidents of construction workers. Accordingly, we analyzed the correlations between the questionnaire tool index that measures the stress associated with complex psychology of humans by integrating emotion, cognition, physical and behavioral responses, and basic brain waves, SEF-90, concentration, stress index from brain wave. As a result, which had the highest correlation with the stress measured through the questionnaire, was the SEF-90, and the regression analysis between two independent variables yielded a specific regression equation. This suggests the possibility of measuring the integrated stress of construction workers through the EEG signal at the construction site, and it can be used for the safety management of the construction site in the future.

• The Journal of the Convergence on Culture Technology
• /
• v.6 no.1
• /
• pp.99-104
• /
• 2020

This paper examines the performance according to the combination pattern of HRM and business strategy. The business strategy was divided into Miles & Snow's prospector, defender, and analyzer. Data were collected from the Korea Labor Institute's workplace panel survey from 2005 to 2015, and the analysis used 465 companies that are common respondents of the six wave surveys. To test the research model, structural equation modeling was employed. The results of the analysis showed that the combination of high commitment HRM and prospector had a positively significant effect on the performance. Contrariwise, the combination of high commitment HRM and defender, the combination of high commitment HRM and analyzer were not significant effect on performance.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.6 no.2
• /
• pp.139-149
• /
• 1994

In this paper, a finite element technique is applied to the prediction of the wave resonance phenomena in harbors. The mild-slope equation is used with a partial reflection boundary condition introduced to model the energy dissipating effects on the solid boundary. For an efficient modeling of the radiation condition at infinity, a new infinite element is developed. The shape function of the infinite element is derived from the asymptotic behavior of the first kind of the Hankel's function in the analytical boundary series solutions. For the computational efficiency, the system matrices of the element are constructed by performing the relevant integrations in the infinite direction analytically. Comparisons with the results from experiments and other solution methods show that the present model gives fairly good results. Numerical experiments are also carried out to determine the proper distance to the infinite elements from the mouth of the halter, which directly affect the accuracy and efficiency of the solution.

• Korean Journal of Social Welfare
• /
• v.58 no.3
• /
• pp.223-244
• /
• 2006

The purpose of this study was to investigate the developmental pathways that mediate the effects of child abuse on delinquency. Data from the first wave of 'Seoul Panel Study of Children(SPSC)' were analyzed. The subjects consisted of 1,811 4th grade students from elementary schools. Structural equation model was employed for statistical analyses. The results showed that the relationship between child abuse and delinquency was indirectly mediated by self-esteem, peer rejection, and school attachment. The hypothesized structural model had a good model fit. Abused children were more likely to have low self-esteem, which was associated with higher levels of delinquency. In addition, abused children were more likely to be rejected by peers and to have low school attachment, which was also associated with higher levels of delinquency. Implications for social work practice from this study were discussed.

• Journal of the Korean Chemical Society
• /
• v.32 no.3
• /
• pp.227-232
• /
• 1988

A kinetic study was made to determine the mechanism of the aquation of $cis-[Co(en)_2(NH_3)Cl]^{2+}\;in\;Hg^{2+}$ aqueous solution. The progress of reaction was followed UV/vis-spectrophotometrically by a measurement of the absorbance at a specific wave length (530nm) of $cis-[Co(en)_2(NH_3)Cl]^{2+}$ as a function of time. The experimental results have shown that the reaction rate is dependent upon the concentration of $Hg^{2+}$ that act as a catalyst. And it was found that the overall reaction proceed with second order, first order with respect to Co(III) complex and $Hg^{2+}$. Activation parameters, ${\Delta}H^{\neq}\;and\;{\Delta}S^{\neq}$, were obtained as 12.9 kcal/mol and -19.3 e.u., respectively. We have proposed a plausible reaction mechanism which is consistent with the observed rate equation.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.27 no.6
• /
• pp.391-405
• /
• 2015

A global tsunami prediction system was suggested for a distant tsunami using a finite fault model and a cyclic boundary condition. The possibility of the suggested system as a distant tsunami response system was checked by applying it into the case of 2014 Chile tsunami. A comparison between the numerical results(tsunami height and arrival time) with different conditions (boundary condition, governing equation, grid size and fault model) and measured data (DART buoy, tide station) showed the importance of the finite fault model and the cyclic boundary condition.