• Journal of Ocean Engineering and Technology
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• v.25 no.2
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• pp.127-133
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• 2011

The following Technology Report was written with respect to recent offshore technology development. This report was prepared with the purpose of suggesting recent offshore technology and upcoming visions by describing the principles of an offshore drilling operation, the NL Tensioner Cylinder Package R & D, and the general technology related to three offshore patent areas, as major contents.

• Journal of electromagnetic engineering and science
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• v.10 no.3
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• pp.150-157
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• 2010

We proposed a $4{\times}8$ array antenna with aperture-coupled patch antenna elements. The antenna was designed for 60 GHz operation and fabrication on the low-temperature cofired ceramic(LTCC) substrate($\varepsilon_r$=5.8). The feedline with the stub was designed to enhance the radiating element bandwidth and the transition characteristics between the waveguide (WG) and microstrip line(MSL). Through the optimization of the antenna and feedline geometry, the antenna gain and the performance of the 10 dB bandwidth were 20.2 dBi and 13 % up, respectively. The measured results agreed with the simulated ones.

• Communications for Statistical Applications and Methods
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• v.27 no.1
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• pp.129-140
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• 2020

In this paper, we introduce an efficient algorithm for the non-convex penalized multinomial logistic regression that can be uniformly applied to a class of non-convex penalties. The class includes most non-convex penalties such as the smoothly clipped absolute deviation, minimax concave and bridge penalties. The algorithm is developed based on the concave-convex procedure and modified local quadratic approximation algorithm. However, usual quadratic approximation may slow down computational speed since the dimension of the Hessian matrix depends on the number of categories of the output variable. For this issue, we use a uniform bound of the Hessian matrix in the quadratic approximation. The algorithm is available from the R package ncpen developed by the authors. Numerical studies via simulations and real data sets are provided for illustration.

• Communications for Statistical Applications and Methods
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• v.21 no.5
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• pp.423-433
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• 2014

Test statistics using cumulative sums of residuals have been widely used in various regression models including generalized linear models(GLM). Recently, Pan and Lin (2005) extended this testing procedure to the generalized linear mixed models(GLMM) having random effects, in which we encounter difficulties in computing the marginal likelihood that is expressed as an integral of random effects distribution. The Gaussian quadrature algorithm is commonly used to approximate the marginal likelihood. Many commercial statistical packages provide an option to apply this type of goodness-of-fit test in GLMs but available programs are very rare for GLMMs. We suggest a computational algorithm to implement the testing procedure in GLMMs by a freely accessible R package, and also illustrate through practical examples.

• Bulletin of the Korean Space Science Society
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• 1993.04a
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• pp.14.2-14
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• 1993

We present UBV CCD Photometry of the very metal-poor globular duster M3O,covering a region of r f 100 arcsec from the duster center. The data was obtained from the 40 inch telescope at Mt Soomlo Siding Spring Observator in August 1992. We used DAOPHOT CCD reudction package for data reduction to obtain Color-Magnitude Diagram(CMD). We have determined some fludamental parameters of the globular Ouster such as metal abundance, helium abundance and distance from the CMD. finally, we have attempted to determine the age of M3O using the revised Yale isochrones.

• The Journal of Information Systems
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• v.20 no.3
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• pp.111-127
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• 2011

This study is intended for international cooperation in the field of LED were analyzed. The results, LED wide coverage areas, and a promising future is expected to grow fast enough to occupancy for a major national technology is a competitive situation. Chip Scale Package, including our country, such as LED manufacturing technology that might be competitive in parts, but new technologies such as renal substrate R&D and technology development still active preemption is not the situation. Renal substrate, particularly, large-diameter sapphire, large size/large LED manufacturers, such as a promising area for future research and development support will be needed. To do this, previous research in this area and the U.S., Japan cooperation in such studies also will need to expand. Bibliometrics way through this study, analytical techniques and analytical tools used in the integrated analysis of the usefulness and necessity of the system development were found.

• 연구논문집
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• s.29
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• pp.173-183
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• 1999

The vacuum investment casting process for a large gas turbine component, Inner Preswirl Support (IPS), was simulated by using commercial FEM package ProCAST(TM) with view factor radiation method. The solid fraction in mushy zone was directly measured by Differential thermal analysis(DTA-DSC mode). Three types gating design. considering liquid flow and heat release through it. were proposed. Solidification had begun at the ribs or thin sections of the IPS casting and advanced further through the upper and lower gates. The computed temperature gradient G and G/R values at 70% solidified temperature were used for prediction of microshrinkage formation during casting. The effect of mold preheat on the thermal history of the casting displayed minute effect on the microshrinkage formation.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.7
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• pp.701-705
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• 2014

This article presents a comparison among several yaw and roll motion controllers for vehicle rollover prevention. In the previous research, yaw and roll motion controllers can be independently designed for rollover prevention. Following this idea, several yaw and roll motion controllers are designed and compared in terms of rollover prevention. For the yaw motion control, PID, LQR, SMC (Sliding Mode Control) and TDC (Time-Delay Control) are adopted. For the roll motion control, LQR, LQ SOF (Static Output Feedback) control, PID, and SMC are adopted. To compare the performance of each controller, simulation is performed on a vehicle simulation package, CarSim$^{(R)}$. From simulation, TDC and LQ SOF are the best for yaw and roll motion control, respectively.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.899-902
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• 2003

Chip Pin Parasitic은 실제 Chip Pad에서부터 Bonding Wire를 통한 Package Lead Frame까지를 의미한다. 여기서, Lead Frame 및 Bonding Wire에서 Inductance 및 작은 저항이 보이고, Chip Pad에서의 Capacitance, 그리고 Pad 부터 Ground까지의 Return Path에서 발생하는 저항이 보인다. 이들을 모두 합하면 L, R, C의 Series로 나타낼 수 있다. 본 논문에서는 이런 Chip Pin Parasitic을 추출 하기 위해서 TDR(Time Domain Reflectometer)과 NA(Network Analyzer)를 사용하였는데, TDR의 경우 PCB를 제작하여 Chip을 Board위에 붙인 후 Time Domain에서 측정 하였고 NA의 경우 Pico Probe를 이용하여 Chip pin에 직접 Probing해서 Smith Chart를 통하여 Extraction 값을 추출했다. 이 경우, NA를 이용한 측정이 좀 더 정확한 Parasitic 값을 추출할 수 있으리라 예상되겠지만, 실제로 Chip이 구동하기 위해서는 Board위에 있을 때의 상황도 고려해야 하기 때문에 TDR 추출 값과 NA 추출 값을 모두 비교하였다.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.79-80
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• 1996

We performed CCD surface photometry in B,V,R and I filters for three southern spiral galaxies:ESO598-G009,NGC1515 and NGC7456. Isophotal map, luminosity profile, ellipticity profile and position angle profile were obtained for these galaxies using SPIRAL package. The results show that one of the galaxies, ESO598-G009 has relatively large bulge component and changes in position angle due to spiral arms. The NGC7456 has very small bulges; and the isophotal map of the NGC1515 shows that it is a typical spiral galaxy with bar.