• Publications of The Korean Astronomical Society
• /
• v.14 no.2
• /
• pp.79-81
• /
• 1999

We have made an extensive mapping of the $^{13}CO$ J=1-0 transition line in the dark cloud L1535. We also constructed the $100{\mu}m$ IRAS map in the region. We found a semi-detached cloud component of $^{13}CO$ in the northeast direction of the $^{13}CO$ main cloud which forms a dumbbell-like structure. This additional component with an angular size of $20'\times16'$ has not been observed before in any molecular surveys of the cloud. The IRAS map shows a similar structure with two intensity peaks whose positions coincide with those of the $^{13}CO$ clouds.

• Proceedings of the KIEE Conference
• /
• 1998.07a
• /
• pp.319-321
• /
• 1998

Some design technologies of AC traction motor for rolling stocks are presented. AC Traction motors for rolling stocks are operated in worst conditions such as frequent mechanical vibrations, compact design with limited mounting space, severe thermal stress at outside, driven with nonsinusoidal voltage waveform inverters, and so on. Therefore, design procedures must be carefully investigated in the viewpoint of theoritically and practical use. Design procedure contains, the motor size determination, electromagnetic circuit design, insulation system design, vibrations and thermal expansion of rotor bars, temperature rise, as well as output characteristics.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.12A
• /
• pp.1145-1151
• /
• 2010

Hochwald et al. introduced unitary space-time codes for quasi-static Rayleigh fading channels which allows for noncoherent decoding when the channel response is not known at the receiver. However, when reliable information on the channel response is available, coherent decoding is preferable for improved performance. Here, we study the relationship between the performance criteria on the diversity and coding advantages provided by unitary space-time codes with noncoherent and coherent decoding. We show that when a unitary space-time code achieves full spatial diversity with noncoherent decoding, full spatial diversity is also guaranteed with coherent decoding.

• Bulletin of the Korean Space Science Society
• /
• 2010.04a
• /
• pp.26.1-26.1
• /
• 2010

In this report, we present newly improved optical design for the Amon-Ra energy channel and its optical performance. The design is optimized parametrically with emphasis on improved light concentration. And then its performances are computed, first, from a laboratory test simulation using laser method (wave optics approach) and, second, from an in-orbit radiative transfer simulation using IRT method with 3D Earth model (geometrical optics approach). Two simulation test results show clear evidence of energy concentration improvement.

• Proceedings of the KIEE Conference
• /
• 2003.11c
• /
• pp.608-611
• /
• 2003

A large part of the embedded system, compared with the PC, have low performance CPU and small memory. So the embedded operating system fits the condition of that hardware system. A Single Address Space (SAS) OS has the operating system and all applications in the single address space. The SAS architecture enhances sharing and co-operation, because addresses have a unique interpretation. Thus, pointer-based date structures can be directly communicated and shared between programs at any time, and can be stored directly on storage. The key point of the SAS OS on the embedded system is the low overhead inter-action between programs in process and usage. So SAS OS can be ported on the low performance CPU. In this paper, we design the SAS OS (named emNOS, Embedded Network Operating System) on the ARMTTDMI processor. Finally we show the benefits of the SAS OS on the embedded system.

• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.1
• /
• pp.66.3-66.3
• /
• 2019

We present near-infrared spectroscopic results for three nearby class I sources, IRAS 03445+3242, IRAS 04239+2436 and ESO $H{\alpha}$ 279a. We detected many molecular and atomic line emissions, e.g., $H_2$, [Fe II], Hydrogen Bracket series recombination, Ca I, Na I & CO overtone band, from these sources using the high-resolution Immersion GRating INfrared Spectrometer (IGRINS; R~45,000). Previous studies showed that all the three sources posses actively accreting Keplerian disks. We performed spectral analysis to understand the origin of Hydrogen Bracket series recombination lines. We also estimated the accretion properties and mass loss rates of circumstellar disks for all the three sources.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.17 no.3
• /
• pp.227-236
• /
• 2015

In impermeable ground, water pressure is applied due to discontinuity such as joint or fissure. Therefore, water pressure should be considered in design regardless of ground condition. However, when the shape of segmental lining is circular, water pressure may reduce the lining member force, so it is important to define the assumption and the concept of design in case of high water pressure. This paper presents the concepts of design of the lining of shield tunnel at high water pressure and in impermeable ground condition. In addition, the member forces in various load conditions were compared in this study. (elastic equation, closed form solutions, beam-spring model).

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.42 no.10
• /
• pp.809-815
• /
• 2014

The co-bonded dissimilar composite under a wide range of temperature change shows thermal distortion due to the differences in thermal expansion characteristics of the composite materials. Analysis of the thermal expansion characteristics of each composite is required for the design of co-bonded dissimilar composite structure with considering the shape distortion during the manufacturing process. In this work, digital image correlation (DIC) technique is introduced for measuring the thermal distortion characteristics of co-bonded dissimilar composite specimen, carbon/epoxy and silica/phenolic. The thermal distortion of co-bonded dissimilar composite specimen is numerically estimated and compared with the experiments. The estimated results is successfully validated using the measured results.

• Journal of Energy Engineering
• /
• v.5 no.1
• /
• pp.65-71
• /
• 1996

Decomposition reaction of methanol was conducted on Ni-Cu/SiO$_2$catalysts with several variables. Variables used in this study are S.V(Space Velocity), partial pressure of methanol, reaction temperature, and composition rate of Ni-Cu. The range of S.V is 10,000-30,000h$\^$-1/, the temperature range is 150-400$^{\circ}C$ and values of Cu/(Ni＋Cu) are 0, 0.25, 0.5, 0.75, and 1. Over Ni/SiO$_2$, and Ni-Cu/SiO$_2$, the conversion rate of decomposition reaction of methanol arrived at 100% with increasing of temperature. At this time the selectivity of CO on Ni/SiO$_2$, was suddenly decreased, but on Ni-Cu/SiO$_2$, it was still sustained highly. The main products of reaction were CO and H$_2$, and by-products were CO$_2$ and CH$_4$mainly.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.44 no.9
• /
• pp.775-780
• /
• 2016

In this paper, a computational algorithm of an improved and versatile structural analysis applicable for large-size flexible nonlinear structures is developed. In more detail, nonlinear finite element based on the co-rotational (CR) framework is developed. Then, a finite element tearing and interconnecting method using local Lagrange multipliers (FETI-local) is combined with the nonlinear CR finite element. The resulting computational algorithm is presented and applied for nonlinear static analyses, i.e., cantilevered beam and multibody structure. Finally, the proposed analysis is evaluated with regard to its parallel computation performance, and it is compared with those obtained by serial computation using the sparse matrix linear solver, PARDISO.