• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.35 no.5
• /
• pp.426-437
• /
• 2007

off-design conditions, supersonic air inlets often encounter the problem of aerodynamic instability, called inlet buzz, which causes the significant degradation of the engine performance. An experimental and numerical study was conducted to investigate the phenomenon of supersonic inlet buzz on a generic, axisymmetric, external-compression inlet with a single-surface center-body. It is understood the mechanism of buzz onset as proving that the origin of buzz is the flow choking induced by separation at the intake throat. Also it is observed the intermittent and continuous buzz mode as area ratio varies and understood the transition process through this study. The buzz frequency become to be higher as decreasing the area ratio, but for each area ratio, the frequency of pressure oscillation is the same at all points of intake.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2006.11a
• /
• pp.331-335
• /
• 2006

Theoretically, stable operations of an inlet are achieved at the design condition. However, at off-design conditions supersonic inlets often encounter the problem of aerodynamic instability, called inlet buzz. During inlet buzz, supersonic inlets exhibit considerable oscillation of the shock system in front of the inlet and corresponding large pressure fluctuations downstream. This phenomenon results in decrease of engine performance. An experimental and numerical study was conducted to investigate the phenomenon of supersonic inlet buzz on a generic, axisymmetric, external-compression inlet with a single-surface center-body. This study suggest that intermittent buzz exist and the frequency become to be large as increasing the back pressure.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2012.07a
• /
• pp.457-458
• /
• 2012

본 논문에서는 실시간 원격 수업(Real-Time Distance Education) 환경 하에서 학생들의 수업 집중 및 효율적인 교수를 위한 버즈학습(Buzz Learning)의 필요성을 제안한다. 이 학습법은 실시간 원격 수업에서 일어날 수 있는 집중력 저하 및 수업참가율 저조를 최소화하고, 학습자 간의 협동 및 상호작용을 향상시킨다. 또한 버즈법에 의한 그룹 편성 및 학습형태는 각 그룹에서 토의한 결과를 다시 전체가 모여 토의함으로써 소집단의 토의결과를 종합 정리하고 결론을 도출해 내는 집단 토의 형태를 띤다. 토의학습은 흔히 몇몇 학생의 경우 토의에 참가하지 않거나 또는 한 명이 독무대화하는 경향이 있는데 여기서는 그룹 전원이 토론에 적극 참여할 수 있게 한다. 본 논문에서는 실시간 원격 수업을 통하여 이뤄지는 실제 강의에 적용된 버즈 학습이 학생들의 수업참여도 및 학습 향상 면에서 우수함을 보여준다.

• 프린팅코리아
• /
• s.54
• /
• pp.168-169
• /
• 2006

기업의 마케팅 무게중심이 B2C에서 C2C로 이동하고 있다. 기업이 소비자에게 파는 것이 아니라 소비자가 소비자에게 홍보하고 제품을 팔아주는 것이다. 이런 버즈 마케팅은 최근 매체광고의 비용 부담 증가와 소비자들의 일방향 광고를 믿지 않으려는 경향이 맞물려 새로운 트렌드로 자리하고 있다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.05a
• /
• pp.88-92
• /
• 2009

Total pressure recovery ratio in intake is crucial factor to the operational characteristics of supersonic propulsion system because it does not compress inlet air mechanically by compressor, but does compress inlet air by ram compression. As the result of that the dynamic characteristic analysis of engine was performed before the controller was designed, it could be ascertained when the AoA of flight vehicle increases, the buzz margin decreases so that the shock wave produced outside intake in the specified area according to flight operation's characteristics. Therefore the PID control algorithm was designed to be controlled buzz margin that the characteristic of shock wave could meet the requirement of performance in intake. The PID controller was designed that the buzz margin value is being positive number using the control variables; fuel flow and nozzle throat area.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.33 no.3
• /
• pp.10-17
• /
• 2005

An experimental study was conducted at a Mach number of 2.0 to investigate the buzz suppression method on an axisymmetric, external compression supersonic inlet. The inlet model has a fixed geometry with no internal contraction. The inlet configuration was altered by changing the cowling. Results show that source of buzz has been related to the existence in the flow field of velocity discontinuity across a vortex sheet which originates from a shock intersection point. With external compression inlet, buzz can be suppressed by positioning the oblique shock slightly inside or outside of the cowl.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.11a
• /
• pp.573-577
• /
• 2009

Dynamic behavior simulation of supersonic engine was performed and PI control algorithm was studied for the buzz control in the inlet and the thrust control. Firstly, required thrust was tracked according to the fuel flow control and then inlet pressure was regulated through the nozzle throat area control so that the buzz margin has the positive all the time. The control was performed according to the change of flight Mach number, altitude and angle of attack. The proportional gain and the integral gain for regulating the buzz margin was induced and simulated. In the results, it was confirmed and satisfied that control target in the operating area was changed the angle of attack from $0^{\circ}$ to $10^{\circ}$ at the flight Mach number of 2.1~3.0.

• Journal of Intelligence and Information Systems
• /
• v.28 no.3
• /
• pp.1-22
• /
• 2022

We investigate the dynamic relationships among digital piracy activities, TV ratings, and online buzz for Korean TV dramas using a panel vector autoregression model. Our main findings include 1) TV ratings are negatively affected by digital piracy activities but positively affected by google buzz, 2) digital piracy activities are negatively affected by TV ratings and social buzz, and 3) social buzz and google buzz are positively influenced by each other. While many empirical studies were conducted to reveal the effects of music or movie piracy, our understanding of drama piracy is limited. We provide empirical evidence of the dynamic relationships between drama piracy, TV ratings, and online buzz. Our findings show the presence of indirect piracy effects on TV ratings through online buzz. Further, we reveal that social buzz and google trends play different roles in promoting TV ratings and piracy activities. We discuss the implications of our findings for theory and practitioners.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.04a
• /
• pp.132-135
• /
• 2011

A technology for buzz margin determination is suggested to obtain stable shock structure and high compression efficiency of supersonic intake. By using the shock equilibrium equation of supersonic intake, sensitivity equation of terminal shock position for free stream and back pressure is induced and disturbances are quantified through statistical approach. Numerical results show that the sensitivity of shock position for disturbances is proportional to Mach number and the back pressure is dominant for variance of terminal shock position.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.10
• /
• pp.2439-2446
• /
• 2013

Recently, SNS (Social Network Service) such as Twitter and Facebook has grown dramatically because of smart phones. Since development of IT has created massive information, social big data extremely increased. Competition between corporations is getting more intense, so they need customer feedback in order to fulfill an effective management. Because social big data plays an important role for getting customer feedback, a lot of corporations are interested in analyzing and applying of social big data. Collecting and analyzing social big data is operated by Buzz monitoring system. This paper demonstrates the research of buzz monitoring system that analyzes big data, and presents examples of customer reputation using buzz monitoring. In the paper, after all, it would analyze the result from the customer reputation, and research the implication.