• Journal of the Korean Institute of Landscape Architecture
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• 제24권3호
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• pp.150-163
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• 1996

This study was carried out to find the general representation methods of wall with respaect to the Korean treaditional atmosphere based on case studies, 16 case studies were classified into two categores : traditional walls and designed walls expressing the treaditional atmosphere. And the representation methods of walls were viewed by two sides : the type of message and the role of sign. The results were summarized as follows ; ■ To reproduce the traditional walls is possible, in this case the role of sign is icon. ■ To reproduce or represint the visual element of the traditional walls will be also possible, in this case the role of sign is index. It is recommended to use 3 types of message in representing methods of walls expressing the Korean traditional atmosphere. ■ Shape ; Approach to shape is more effective than maerial or figure. It is possible to represent the shape element of the traditional walls. Specially, it will be effective to utilize the capital of traitional walls as shape element. ■ Material ; Conventional materials with less artificial processing used at traditional walls will be better suited. ■ Figure ; To utilize the traditional figures is possible. Specially, it will be effective to utilize the traditional figures as design approach with respaect to the sense of place. Futher research is required to find out the relationship between the meaning and the design mechanics.

• The Journal of Korea Robotics Society
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• 제12권4호
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• pp.402-410
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• 2017

Acoustic based localization is essential to operate autonomous robotic systems in underwater environment where the use of sensorial data is limited. This paper proposes a localization method using artificial underwater acoustic sources. The proposed method acquires directional angles of acoustic sources using time difference of arrivals of two hydrophones. For this purpose, a probabilistic approach is used for accurate estimation of the time delay. Then, Gaussian sum filter based SLAM technique is used to localize both acoustic sources and underwater vehicle. It is performed by using bearing of acoustic sources as measurement and inertial sensors as prediction model. The proposed method can handle directional ambiguity of time difference based source localization by generating Gaussian models corresponding to possible locations of both front and back sides. Through these processes, the proposed method can provide reliable localization method for underwater vehicles without any prior information of source locations. The performance of the proposed method is verified by experimental results conducted in a real sea environment.

• Journal of Sensor Science and Technology
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• 제8권4호
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• pp.347-353
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• 1999

We constructed an interferometer for precise measurement of the ball diameter, and measured the diameter of steel ball with a diameter of 78 mm. The interferometer was consisted of etalon to instal ball between two parallel plates and placed on the monolithic flexure to be moved parallel. The ball diameter was calculated from phase difference of one pair of signals interfered between the both sides of ball and two parallel plates, and the signals was observed by photodetectors with scanning the etalon. The results showed that the diameter of steel ball was 78.1893544 mm and measurement uncertainty of 29 nm in confidence level of 95.5%.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권9호
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• pp.2253-2265
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• 2012

A novel folded dipole type microstrip patch antenna designed for ultrahigh frequency (UHF) band radio frequency identification (RFID) tag is presented in this paper, which can be used on the metallic objects. The presented antenna is fabricated on a very thin Rogers 5880 substrate with a thickness of 0.508 mm. The structure consists of two folded dipole and two symmetrical shorting pins placed at both sides of feed point. An adjustable frequency response can be easy obtained via modify the location and radius of the shorting pins. The antenna has been analyzed by full wave simulations soft. The simulated bandwidth is about 67.2 MHz, which covers the Europe and North America UHF RFID frequency range. A manufactured prototype has been fabricated and measured to demonstrate the antenna performances. The simulation results agree with the measurement data well. The measured maximum reading range of the prototype can be reached 4.1 m in free space, and 3.2 m on a metal plate whose size is $150{\times}150{\times}8mm^3$.

• Journal of The Korean Astronomical Society
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• 제37권4호
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• pp.249-255
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• 2004

Here we present a linear stability analysis and an MHD 2D model for the Parker-Jeans instability in the Galactic gaseous disk. The magnetic field is assumed parallel to a Galactic spiral arm, and the gaseous disk is modelled as a multi-component, magnetized, and isothermal gas layer. The model employs the observed vertical stratifications for the gas density and the gravitational acceleration in the Solar neighborhood, and the self-gravity of the gas is also included. By solving Poisson's equation for the gas density stratification, we determine the vertical acceleration due to self-gravity as a function of z. Subtracting it from the observed gravitational acceleration, we separate the total acceleration into self and external gravities. The linear stability analysis provides the corresponding dispersion relations. The time and length scales of the fastest growing mode of the Parker-Jeans instability are about 40 Myr and 3.3 kpc, respectively. In order to confirm the linear stability analysis, we have performed two-dimensional MHD simulations. These show that the Parker-Jeans instability under the self and external gravities evolves into a quasi-equilibrium state, creating condensations on the northern and southern sides of the plane, in an alternate manner.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.452-455
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• 2004

The influence of wake flow on a flat-plate blade having different shapes near the hailing edge has been investigated in this paper. Two different shapes near the trailing edge namely the pressure surface cutting (TP) and the suction surface cutting (TS) have been used. The calculation has been performed for two different angles of attack (a =10 and 15 degree) in both the cases. RANS equations have been solved using SST-model as a turbulence closure. Cp and CL values obtained for TS are higher compared to those obtained for TP. Also, the vorticity distribution obtained in case of TS is stronger as compared to that obtained in the case of TP The Karmann Vortex is observed in both the cases but it is more clear in TS case. It is found that in the case of TS, flow separation does not occur upto the trailing edge on both the suction and the pressure sides of the blade while in the case of TP, the flow separateson the pressure surface near the trailing edge of the flat-plate blade.

• Journal of Microbiology and Biotechnology
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• 제23권2호
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• pp.144-148
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• 2013

Lycopene cyclase converts lycopene to ${\beta}$-carotene by catalyzing the formation of two beta-rings at each end of the linear carotene structure. This reaction takes place as a two-step reaction in which both sides of of the lycopene molecule are cyclized into ${\beta}$-carotene rings via the monocyclic ${\gamma}$-carotene as an intermediate. The crtY gene coding for lycopene cyclase from Paracoccus haeundaensis consists of 1,158 base pairs encoding 386 amino acids residues. An expression plasmid containing the crtY gene (pET44a-CrtY) was constructed and expressed in Escherichia coli, and produced a recombinant protein of approximately 43 kDa, corresponding to the molecular mass of lycopene cyclase. The expressed protein was purified to homogeneity by His-tag affinity chromatography and showed enzymatic activity corresponding to lycopene cyclase. We also determined the lycopene substrate specificity and NADPH cofactor requirements of the purified protein. The $K_m$ values for lycopene and NADPH were 3.5 ${\mu}M$ and 2 mM, respectively. The results obtained from this study will provide a wider base of knowledge on the enzyme characterization of lycopene cyclase at the molecular level.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 한국항해항만학회 2002년도 춘계학술대회논문집
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• pp.13-19
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• 2002

In inner harbour of Inchon Port, there are two lock gates (50KT, 10KT) which have two gates per lock gate in inner/outer sides except a gate in inner harbour side 7f 10KT. Due to the lack of the fore-mentioned gate, the use of 10KT lock gate Is suspended in every 3 years for regular maintenance. Now an additional gate is under construction in order to improve the efficiency of the 10KT lock gate. This paper will be aimed to evaluate the operational utilization levels of lock gates in present and future. The present operational utilization levels of lock gates are 0.2119 in 10KT lock gate, 0.2051 in 50KT lock gate which were considered the 46.5 closed days every 3 years for 10KT regular maintenance. The levels are estimated to 0.2246(10KT), 0.2539(50KT) in 2006 and 0.2241(10KT), 0.2560(50KT) in 2011. The levels of 50KT lock gate are evaluated to be more rapidly increased up to 24.5% in 2011.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제59권2호
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• pp.380-384
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• 2010

A micromirror for a laser display system actuated by the electromagnetic force induced by the surface coil and the permanent magnet was designed and analyzed through the coupled physics analyses incorporating the electromagnetics, mechanics, and electrothermal analysis because the mechanical rotation of the micromirror is driven by the electromagnetic driving force. The proposed micromirror has two torsion beams to sustain the mirror plate which has surface coils on the top and the two permanent magnets exists on both sides of the micromirror for an external magnetic field source. The designed micromirror has the resonant frequency of 3.82kHz. When the magnetic field of the permanent magnet is 0.4T, the coil has 4 turns, and the current density of coil is 3.6A/$mm^2$, the estimated z axis displacement of the mirror plate edge is 0.23mm which corresponds to the rotation angle of $14.2^{\circ}$. When considering the joule heating in the current-carrying coil, the maximum temperature of the mirror plate is obtained as 300.045K, which induces the negligible changes in the rotation angle and the resistance of the coil.

• Journal of Power Electronics
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• 제13권1호
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• pp.20-30
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• 2013

This paper presents a soft switching DC/DC converter for high voltage application. The interleaved pulse-width modulation (PWM) scheme is used to reduce the ripple current at the output capacitor and the size of output inductors. Two converter cells are connected in series at the high voltage side to reduce the voltage stresses of the active switches. Thus, the voltage stress of each switch is clamped at one half of the input voltage. On the other hand, the output sides of two converter cells are connected in parallel to achieve the load current sharing and reduce the current stress of output inductors. In each converter cell, a half-bridge converter with the asymmetrical PWM scheme is adopted to control power switches and to regulate the output voltage at a desired voltage level. Based on the resonant behavior by the output capacitance of power switches and the transformer leakage inductance, active switches can be turned on at zero voltage switching (ZVS) during the transition interval. Thus, the switching losses of power MOSFETs are reduced. The current doubler rectifier is used at the secondary side to partially cancel ripple current. Therefore, the root-mean-square (rms) current at output capacitor is reduced. The proposed converter can be applied for high input voltage applications such as a three-phase 380V utility system. Finally, experiments based on a laboratory prototype with 960W (24V/40A) rated power are provided to demonstrate the performance of proposed converter.