• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.597-600
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• 2002

In general, the function of intake structure, whether it be a open channel, a fully wetted tunnel, a sump or a tank, is to supply an evenly distributed flow to a pump station. An even distribution of flow, characterized by strong local flow, can result in formation of surface or submerged vortices, and with certain low values of submergence, may introduce air into pump, causing a reduction of capacity and efficiency, an increase in vibration and additional noise. Uneven flow distribution can also increase or decrease the power consumption with a change in total developed head. To avoid these sump problems pump station designers are considered intake structure dimensions, such as approaching upstream, baffle size, sump width, width of pump cell and so on. From this background, flow characteristics of intake within sump are Investigated numerically to obtain the optimal sump design data. The sump model is designed in accordance with HI code.

• 대한기계학회논문집A
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• 제25권4호
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• pp.695-702
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• 2001

In this paper, the drop/impact simulation for a mobile phone has been carried out with the explicit code LS-DYNA and its validation has been experimentally verified. The small size of this kind of electronics products makes it time-consuming, and difficult to conduct drop tests to detect the failure mechanism and identify their drop behaviors. Strict drop/impact performance criteria of such hand held electronic products as mobile phones play an important role in their design because these products must withstand both normal and unexpected shock. Usually, the product durability on drop impact depends on designers experience. The present reliable methodology of drop/impact simulation provides an efficient and powerful vehicle to improve the design quality and reduce the design period.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.110-113
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• 2007

난류 고리가 장착된 가스발생기의 난류 생성을 연구하기 위하여 LES 코드가 개발되어 검증을 하였다. 난류 고리의 형상과 길이를 변경에 따른 난류 발생 정도를 비교하였으며, 혼합 정도를 비교하기 위하여 유동장의 변동 속도를 이용한 두 가지 변동량의 값을 구하였으며, 혼합 정도를 정량화 하였다.

• Computers and Concrete
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• 제2권2호
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• pp.111-123
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• 2005

The ductility of reinforced concrete bearing walls subjected to high axial loading and moment can be enhanced by improving the deformability of the compression zone or by reducing the neutral axis depth. The current state-of-the-art procedure evaluating the confinement effect prompts a consideration of the spaces between the transverse and longitudinal reinforcing bars, and a provision of tie bars. At the same time, consideration must also be given to the thickness of the walls. However, such considerations indicate that the confinement effect cannot be expected with the current practice of detailing wall ends in Korea. As an alternative, a comprehensive method for dimensioning boundary elements is proposed so that the entire section of a boundary element can stay within the compression zone when the full flexural strength of the wall is developed. In this comprehensive method, the once predominant code approach for determining the compression zone has been advanced by considering the rectangular stress block parameters varying with the extreme compression fiber strain. Moreover, the size of boundary elements can also be determined in relation to the architectural requirement.

• Steel and Composite Structures
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• 제7권3호
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• pp.201-217
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• 2007

Two combinatorial optimization algorithms, tabu search and simulated annealing, are presented for the minimum-weight design of geometrically non-linear steel plane frames. The design algorithms obtain minimum weight frames by selecting suitable sections from a standard set of steel sections such as American Institute of Steel Construction (AISC) wide-flange (W) shapes. Stress constraints of AISC Load and Resistance Factor Design (LRFD) specification, maximum and interstorey drift constraints and size constraints for columns were imposed on frames. The stress constraints of AISC Allowable Stress Design (ASD) were also mounted in the two algorithms. The comparisons between AISC-LRFD and AISC-ASD specifications were also made while tabu search and simulated annealing were used separately. The algorithms were applied to the optimum design of three frame structures. The designs obtained using tabu search were compared to those where simulated annealing was considered. The comparisons showed that the tabu search algorithm yielded better designs with AISC-LRFD code specification.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.1105-1108
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• 1999

In this paper, we propose a new addressing mode, which can be used for programmable image processor to perform image- processing algorithms effectively. Conventional addressing modes are suitable for one-dimensional data processing such as voice, but the proposed addressing mode consider two-dimensional characteristics of image data. The proposed instruction for two-dimensional addressing requires two operands to specify a pixel and doesn't require any change of memory architecture. Combining several instructions to load a pixel-data from an external memory to a register, the proposed instruction reduces code size so that satisfy hish performance and low power requirements of image processor. In addition, it uses inherent two-dimensional characteristics of image data and offers user-friendly instruction to assembler programmer.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.465-468
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• 2003

In industry areas, a lot of factories and process plants need network for processing data acquired from field and for communicating between sensors or actuators or field controllers. Most of the industry networks are based on wired solutions. But, recently, a lot of factories and process plants are moving into wireless solutions since they have some advantages compared with wired one. In this paper we first review the characteristics of wired and wireless network technologies and introduce the new technique called wireless sensor network (WSN). And then we describe the wireless sensor node system designed by us for WSN which has the ability of small size, flexibility and low-power consumption and embedded into the Bar-code scanner to communicate each other. Finally, we conclude this paper by showing that wireless industry network can be constructed with wireless sensor network without large change of traditional wired topologies through experiment using wireless sensor nodes.

• 천문학회보
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• 제42권1호
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• pp.31.2-31.2
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• 2017

The central regions of barred-spiral galaxies contain interesting gaseous structures such as dust lanes and nuclear rings with intense star formation. While our previous studies were useful in understanding the formation of these structures star formation history, they were limited to 2D isothermal galaxies in which the stellar disk and halo are modeled by fixed gravitational potentials. To study the effects of bar growth as well as the vertical dimension, we use the mesh-free hydrodynamic code named GIZMO and run 3D simulations by treating the stellar disk and halo as being live. We find that the new 3D models form the gaseous features similarly to the previous 2D models, although the detailed formation processes are quite different. For example, a ring has a large radius when it first forms and shrinks over time in the previous 2D models. In the 3D live-potential models, however, a ring forms small and grows in size with time. We present the results of the new simulations and discuss them in comparison with the previous 2D results.

• 천문학회보
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• 제43권1호
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• pp.35.2-35.2
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• 2018

Magnetic fields in clusters of galaxies play a critical role in shaping up the intracluster medium. Their existence has been established through observations of synchrotron emission, especially from radio relics and halos, as well as observations of rotation measure. In the so-called Sausage relic, which is one of Mpc-size giant radio relics detected in the outskirts of merging clusters, for instance, the magnetic fields are believed to have a few ${\mu}G$ strength and a Mpc scale. The observed magnetic fields are conjectured to be produced by the process of small-scale turbulence dynamo. To investigate the dynamo origin, we simulate the development of turbulence and the follow-up amplification of magnetic fields in galaxy clusters using a three-dimensional magnetohydrodynamical(MHD) code. Turbulence is induced in highly stratified backgrounds expected in clusters, and driven sporadically mimicking major mergers. We here present preliminary results, aiming to answer whether the turbulence dynamo scenario can explain observed magnetic fields in clusters of galaxies.

• 전자공학회논문지C
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• 제34C권8호
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• pp.1-7
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• 1997

In tis paper, w eproposed a modeling for direct-sequence spread communication base band modem in RT-level VHDL and implemented in a one-chip VLSI and tested. The transmitter modulates with DQPSK modulation method and spreads a modulated signal with 32-bit PN code into 1.152MHz. The receiver de-spreads a signal using 32-tap matched filter and recovers with DQPSK demodulation method. The digital frequency synthesizer generates the sine signal and the cosine signal of 2.304MHz with ROM tables in the size of 7$\^$*/256 and 6$\^$*/256, respectively. The implemented VLSI has been verified a BER with 10$\^$-4/ at E$\_$b//N$\_$o/ of 13dB with a SPW fixed design model and fabricated in the 0.8.mu.m KG6423 gate array with a VHDL model.