• 한국항공우주학회지
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• 제33권8호
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• pp.42-49
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• 2005

아음속풍동 폐쇄형 시험부의 벽면효과 보정을 위한 새로운 blockage 보정 기법을 개발하였다. 개발된 보정 기법은 실속항력계수와 separation blockage의 비선형 관계를 이용하여 선형 양력곡선 기울기 영역에서 후실속 영역까지 실시간으로 보정이 가능하게 하였다. 본 연구에서 제시한 방법은 bluff body 시험 결과를 사용하는 고전적 방법과 벽면압력측정 방법과 비교하여 그 타당성을 검증하였다. 그 결과 본 연구에서 제시한 보정 방법은 실속 및 후실속 영역에서 bluff body 방법보다 우수한 보정 결과를 보이며 벽면압력측정 방법과 같은 정확도로 보정됨을 확인할 수 있었다.

• 한국의상디자인학회지
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• 제6권2호
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• pp.15-20
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• 2004

These days are referred to as 'the times of textile fashion,' owing to the emphasis on textile design in the fashion industry. Accordingly, apparel companies have increased their interests in developing new types of textiles to overcome the limits of style and silhouette. Now the ultra-fashion of textile, a new way of process and design development, is given much more attention. A Moire interference pattern has a longer wavy circle of interference, an effect of intensity interference, than one made by piling more than one reflecting plate or transmitting plate. Till now, Moire interference patterns have been used to confirm scientific theory and to measure the structure of a body or a subject in areas such as physics and medical science. Work has also been done on the Moire interference effects on TV screens said to cause dizziness and eye strain. This study focuses on the new types of textiles by creating the appearance of the Moire phenomena. Contrary to the present usual stationary patterns of textiles, it is a varying pattern according to the different gratings, different angles, piling gratings, and the movements of the human bodies. In the preceding study, we observed Moire fringes formed by overlapping two different or same kinds of gratings such as parallel line gratings, square gratings, conic gratings and semicircular gratings and tried to find a promising possibility of new textiles through the method of clothes design simulation.

• 한국전산유체공학회지
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• 제19권2호
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• pp.99-107
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• 2014

The aim of the present study is to investigate the flow interference between two adjacent undulating fish-like body, and its effect on the undulating propulsion. For this purpose, unsteady two dimensional incompressible flow calculations were conducted using an unstructured mesh flow solver, coupled with an overset mesh technique. To deal with mesh deformation due to fish locomotion, spring analogy is utilized. The fish body used in the simulation is constructed from the NACA0012 airfoil. The study indicates that the propulsion of undulating fish is proportional to frequency and wavelength of the midline oscillation when there is no adjacent fish. It also reveals that average thrust was increased when the vortex shedding from the tail was conserved well and pressure difference between upper and lower sides of the fish was magnified due to flow interference. From this study, which relative position and phase difference of locomotion between two fishes can generate maximum thrust was known among six different cases.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.973-975
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• 2016

본 논문에서는 센서 결합을 이용하여 강체 자세 추정을 정확히 할 수 있는 선택적 확장 칼만 필터 방법을 제안한다. 강체의 자세는 Gauss-Newton방법을 적용하여 가속도 데이터와 지자기 데이터로 부터 쿼터니언 상태 변수를 개략 추정하고 비전 정보와 자이로 센서 정보를 이용하여 정밀 추정을 하는데 외부 간섭 잡음이 강 할 경우 이 방식을 이용한 개략 추정이 어려워진다. 본 논문은 외부 간섭 잡음의 정도를 측정하고 잡음이 강할 때 비전 정보와 자이로 센서정보를 주로 이용하는 선택적 확장 칼만 필터 방법을 이용하여 추정 값에 대한 신뢰도를 높인다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권11호
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• pp.5218-5233
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• 2018

The coexisting wireless body area networks (WBAN) is a very challenging issue because of strong inter-networks interference, which seriously affects energy consumption and spectrum utilization ratio. In this paper, we study a power control strategy with nearest neighbor nodes distribution for coexisting WBAN based on stochastic geometry. Using homogeneous Poisson point processes (PPP) model, the relationship between the transmission power and the networks distribution is analytically derived to reduce interference to other devices. The goal of this paper is to increase the transmission success probability and throughput through power control strategy. In addition, we evaluate the area spectral efficiency simultaneously active WBAN in the same channel. Finally, extensive simulations are conducted to evaluate the power control algorithm.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1730-1735
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• 2003

The plume-induced shock wave is a complex phenomenon, consisting of plume-induced boundary layer separation, separated shear layer, multiple shock waves, and their interactions. The knowledge base of plume interference effect on powered missiles and flight vehicles is not yet adequate to get an overall insight of the flow physics. Computational studies are performed to better understand the flow physics of the plume-induced shock and separation particularly at high plume to exit pressure ratio. Test model configurations are a simplified missile model and two rounded and porous afterbodies to simulate moderately and highly underexpanded exhaust plumes at the transonic/supersonic speeds. The result shows that the rounded afterbody and porous wall attached at the missile base can alleviate the plume-induced shock wave phenomenon, and improve the control of the missile body.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권5호
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• pp.2081-2101
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• 2016

Successive interference cancellation (SIC) is considered to be a promising technique to mitigate multi-user interference and achieve concurrent uplink transmissions, but the optimal power allocation (PA) issue for SIC users is not well addressed. In this article, we focus on the optimization of the PA ratio of users on an SIC channel and analytically obtain the optimal PA ratio with regard to the signal-to-interference-plus-noise ratio (SINR) threshold for successful demodulation and the sustainable demodulation error rate. Then, we design an efficient resource allocation (RA) scheme using the obtained optimal PA ratio. Finally, we compare the proposal with the near-optimum RA obtained by a simulated annealing search and the RA scheme with random PA. Simulation results show that our proposal achieves a performance close to the near-optimum and much higher performance than the random scheme in terms of total utility and Jain's fairness index. To demonstrate the applicability of our proposal, we also simulate the proposal in various network paradigms, including wireless local area network, body area network, and vehicular ad hoc network.

• Tribology and Lubricants
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• 제40권1호
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• pp.24-27
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• 2024

A monotype valve body for a dual clutch transmission has the potential to reduce costs, weight, and manufacturing time by modularizing various parts, including those of existing solenoid packs and valve bodies, into one through the application of super-precision die casting technology. However, this approach may lead to challenges such as reduced rigidity and increased interference due to modularization and compactness, impacting both product performance due to the reduced weight as well as durability and reliability. Unlike existing products, this approach requires a high-precision thin-wall block to avoid more complicated flow line formation, interference between flow lines, and leaks, as well as a strict quality requirement standard and precise inspections including detection of internal defects. To conduct precise inspections, we built an equivalent model corresponding to a driving distance of 300,000 km. Testing involved simulating actual road loads using a real vehicle and a chassis dynamometer in the FTP-75 mode (EPA Federal Test Procedure). The aim of the study was to establish a vehicle load-based part durability model for manufacturing a mono-type valve body and to develop fundamental technology for part weight reduction through preliminary design by introducing analytical weight reduction technology based on the derived results.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1871-1875
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• 2003

The cancellation of the output signal occur between output tubs have occurred place an electromagnetic interference and deteriorated the light efficiency of the neon tub. In order to prevent this problems, we have developed the modified electronic ballast for neon(MEBN). The MEBN have used a shielded line to the output and designated partly the half-bridge in the middle of the circuit. In an experimental results, this will be lengthen the life of the neon tub and obtain the effect which shields an electromagnetic wave to injurious to the people’s body.

• 한국철도학회논문집
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• 제2권2호
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• pp.13-20
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• 1999

The vibration signals of driving parts of electric train are distorted its signal patterns due to the impact components, which occurs when wheel passes rail joints. An elimination method of the impact components is investigated using adaptive signal processing technique in this study The result shows that adaptive interference canceling method seems to be more effective than line enhancement technique. The application of adaptive interference canceling method to the signal measured at bogie shows that the extractions of the signals of driving parts of traction motor, reduction gear, and axle bearing are successful. Therefore, only the signals of bogie, which is the place to attach an accelerometer easily, is sufficient for the fault diagnosis and the safety evaluation of electric train. Also, adaptive interference canceling method can be applicable to evaluate the performance of vibration isolation between bogie and car body and to investigate the characteristics of indoor sound.