• Journal of Labour Economics
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• v.40 no.1
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• pp.69-97
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• 2017

This paper estimates the public and private sector wage gap trend from 2000 to 2014 using 'Korean Labor and Income Panel Study.' We account for unobserved fixed effect by using 1st differencing log wage in order to allow the gap to vary over time. Standard OLS estimates present the public sector wage is 10% higher than private sector on average. Moreover, the public sector wage premium displays the inverted V shape: sharply increasing up to 2006 and decreasing from 2007 to 2014. However, after controlling unobserved fixed effect, the public sector wage premium disappears and does not display the inverted V shape any more.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.370-370
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• 2012

Feature size of Cu interconnects keep shrinking into several tens of nanometer level. For this reason, the Cu interconnects face challenging issues such as increase of electro-migration, line-width dependent electrical resistivity increase, and gap-filling difficulty in high aspect ratio structures. As the thickness of the Cu film decreases below 30 nm, the electrical resistivity is not any more constant, but rather exponential. Research on alloying with other elements have been started to inhibit such escalation in the electrical resistivity. A faint trace of Al added in Cu film by sputtering was reported to contribute to suppression of the increase of the electrical resistivity. From an industrial point of view, we introduced cyclic metal organic chemical vapor deposition (MOCVD) in order to control Al concentration in the Cu film more easily by controlling the delivery time ratio of Cu and Al precursors. The amount of alloying element could be lowered at level of below 1 at%. Process of the alloy formation was applied into gap-filling to evaluate the performance of the gap-filling. Voidless gap-filling even into high aspect ratio trenches was achieved. In-depth analysis will be discussed in detail.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.5
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• pp.87-93
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• 2005

In order to develope high concentration$\cdot$yield ozonizer, superposed discharge type ozonizer using overlap of silent discharge and internal electrode of mesh type has been designed and manufactured. It consists of three electrodes(central electrode, internal electrode and external electrode) and double gaps(gap between central electrode and internal electrode, gap between internal electrode and external electrode). Therefore, ozone is generated by overlapping silent discharges generated between the gaps respectively for which the AC high voltages applied to the internal electrode and the external electrode has a $180{[^\circ]}$ phase difference and for which the central electrode is a ground Ozone generation characteristics proportional to mesh of internal electrode by increasing of discharge electrode and controlling of discharge power density. As a result, the in maximum ozone concentration, generation, and yield can be obtained 17,720[ppm], 5.4[g/h], and 205[g/kwh] respectively.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.409-412
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• 2006

Bulk metallic glass (BMG) strips of $Cu_{54}Ni_6Zr_{22}Ti_{18}$ were produced by warm rolling of the amorphous powder canned with copper. Controlling of temperatures of the rolled sample and rolls was essential for the successive rolling process. Because improper controlling of the sample temperature gave rise to the crystallization of BMG loading to the catastrophic fracture of BMG strips, the temperature of rolls should be properly controlled for achieving successful powder rolling of BMG. The variations of the strain state and temperature in the roll gap was simulated by the finite element method(FEM) using various roll temperatures.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1846-1848
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• 1999

A technique is investigated for achieving broadband properties by controlling the operation frequency of microstrip antennas. The control is achieved by applying DC and AC bias to the microstrip antenna. Air gap antenna with pzt post and microstrip antenna with simple rectangular patch on the $LiNbO_3$ substrate were fabricated. In the case of Air gap antenna, the variation of operating frequency was 11Mhz and $LiNbO_3$ antennas was 11Mhz. Also, frequency scanning was achieved by appling AC bias.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.678-684
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• 2011

In 2013, Korea will become the world's second country to operate the urban Maglev system with the inauguration of demonstration line at Incheon International Airport. A prototype Maglev is under the test at KIMM's(Korea Institute of Machinery & Materials, Daejeon) track. This Maglev is an EMS(Electromagnetic suspension)-type vehicle of controlled $8{\pm}3mm$ air gap. The air gap between electromagnet and the guiderail in an EMS-type Maglev must be maintained within an allowable deviation by controlling the magnet. The air gap response is strongly dependent on the structural characteristics of the elevated guideway. For this reason, the interaction between the vehicle with electromagnets and the elevated guideway must be understood to ensure safe running. The purpose of this paper is to compare vibration characteristics of the vehicle on the switching system and other sections when the full weight condition of urban maglev vehicle that 26.5 tons per car(empty car weight 19 tons + passenger condition 7.5 tons), is applied. Through such results, Maglev vehicles and switching system can be established and the levitation stability can be improved.

• The Journal of the Acoustical Society of Korea
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• v.31 no.8
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• pp.580-589
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• 2012

In this paper, we studied on Doppler gap-filling algorithms suitable for a portable or low-cost medical ultrasound imaging system, and as a result, found out algorithms based on mirroring or autoregressive model. Moreover, controlling the computational demand in the proper range, we improved the performances of these algorithms by solving their problems. Effectiveness of these modified algorithms is verified by computer simulations and experiments which used artificially generated Doppler signals and Doppler data acquired from human body through an actual ultrasound system.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.1 s.34
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• pp.73-76
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• 2005

To widen the band gap of ZnO, we have investigated $Zn_{1-x}Mg_xO(ZMO)$ thin films prepared by pulsed laser deposition on c-plane sapphire substrates at $500^{\circ}C$. From X-ray diffraction patterns, ZMO films show only the (0002) and (0004) diffraction peaks. It means that the flints have the wurtzite structure. Segregation of ZnO and MgO phases is found in the films with x=0.59. All the samples are highly transparent in the visible region and have a sharp absorption edge in the UV region. The shift of absorption edge to higher energy is observed in the films with higher Mg composition. The excitonic nature of the films is clearly appeared in the spectra for all alloy compositions. The optical band-gap ($E_g$) of ZMO films is obtained from the ${\alpha}^2$ vs Photon energy plot assuming ${\alpha}^2\;\propto$ (hv - $E_g$), where u is the absorption coefficient and hv is the photon energy. The value of $E_g$ increases up to 3.72 eV for the films with x=0.35. It is important to adjust Mg composition control for controlling the band-gap of ZMO films.

• Journal of the Korean housing association
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• v.6 no.1
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• pp.9-17
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• 1995

The purpose of this study is designed for showing informations about demand of consumers in the market field. the uses and awareness of curtain of consumers and specialists and the way of better choice of curtain that is important in controlling the interior style. This study results that researched the uses and awareness of consumers and specialists about curtain were as follows. Curtain is important interior equipment point. and large gap is not between consumers and specialists about curtain. but consumers emphasized function and specialists emphasized designe of curtain.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.137-140
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• 2007

We prepared ambipolar organic field-effect transistors and observed blue emission when both hole and electron accumulation layers were in the channel. We found that the reduction of carrier traps and controlling devices' preparation and measurement conditions were crucial for ambipolar operation.