• Journal of Navigation and Port Research
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• v.28 no.6
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• pp.491-496
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• 2004

The paper describes measurement techniques for an acoustic transfer characteristic of ship's bridge stimulated by a whistle sound The response sounds, according to the opening-shutting conditions of bridge doors for Training Ship ‘SAENURI’, are measured by B＆K 2260D equipment, and then the frequency responses are extracted by B＆K 7830 software. To evaluate the measured transfer characteristic, the 128th order FIR (Finite Impulse Response) filters, containing the different frequency characteristics, are constructed based on the frequency sampling-based design method Using evaluation indexes with six scales, psychological assessments by five subjects are carried out with test sounds which are obtained from convolving the source signal with FIR filters. As results of tests, the test sounds gives $A_S$ 3.3∼4.7 which means the psychological sense of ‘it is almost similar sound as original ones in a real world’, and thus it is clearly seen that the proposed method can be used for the measurement of an acoustic transfer characteristic of ship’s bridge.

• (The)Study of the Eastern Classic
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• no.69
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• pp.419-450
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• 2017

This study aims to discover the clue of the current modern postal system development by looking at the delivery patterns of Korean letters during the Joseon Dynasty. A letter is a text medium that the sender sends to a recipient by sending a message of news. The form and contents of the letter are influenced by the various surrounding factors and are adapted to circumstances. The study aims to clear up the method of delivery and the nature of the transmitter among the environmental factors which affects the format and contents of Korean letters. Depending on the public or private matters, the delivery method is divided into a public agency and a private messenger, or divided into one-phase delivery and the multi-phase delivery depending on whether or not a phase is divided into stages. It is also divided into a one-way and a round-transmission depending on whether or not it is round-switched. The transmitter is divided into a verbal communication, the letter and verbal communication, and the letter communication according to whether or not it is by verbal, and divided into the relational and the non-relational person according to the relationship with the sender. Also depending on whether the transmitter is exclusive or not, it is divided into the exclusive messenger and the messenger who deliver a letter incidentally while come and go. In the aspect of the delivery method, We can see the possibility of developing to a modern mail system through the public method, the multi-phase delivery, one-way delivery and in the aspect of the transmitter, we can see the possibility through the letter delivery, non-related transmitter, and the exclusive messenger.

• Journal of IKEEE
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• v.20 no.4
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• pp.416-419
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• 2016

When the integration density and operating frequency increase in the electronic circuits, it is important to improve the signal transmission characteristics. In this paper, the signal transmission characteristics of the printed circuit boards are analyzed with the curvature of the pads. From the simulation results, signal transmission characteristics are improved when pad curvature increases. Pad curvature more effects on signal transmission characteristics when the thickness of the transmission line and the length of the transmission decrease.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.10a
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• pp.282-288
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• 1998

본 논문에서는 뉴로-퍼지 제어기를 이용하여 밀폐공간에서의 능동 소음 제어기를 구현하였다. 능동 소음 제어기는 잡음에 의하여 왜곡된 신호로부터 잡음을 제거하여 원 신호를 복원하는 제어시스템이다. 일반적으로 잡음의 특성이 시간에 따라 변화라고, 전달특성이 비선형적이므로 고정된 제어기에 의해서는 제어할 수 없다. 이 논문에서는 뉴로-퍼지 제어기를 사용하여 파라미터를 오차 역전파 학습을 통하여 변화시킴으로써 잡응의 특성에 효과적을 적응하는 능동 소음 제어기를 구성하였다. 원신호는 음성신호를 사용하였으며 실제 소음과 소음 전달경로인 1차경로를 통과한 왜곡된 소음은 실험에 의해 얻은 데이터를 사용하였다. 제어신호의 전달경로인 2차경로는 100[kHz]에서 1[kHz]까지의 주파수 특성을 고려하여 curve fitting 방법을 사용하여 4차로 모델링한 결과를 사용하였다. 제안한 능동 소음 제어기의 성능을 시뮬레이션을 통하여 확인하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.202-205
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• 2002

본 논문은 계속적인 소자의 이용은 전기적인 스트레스까지 야기시키는데, 특히 게이트에 인가되는 전압이나 전류 스트레스는 게이트 산화 막의 열화를 야기 시킬 수 있다. 유리기판위에 저온(${\leq}600^{\circ}C$)공정의 고상결정화을 통하여 다결정 박막 트랜지스터를 제작한 후, 이 소자에 게이트와 드레인에 전압 스트레스를 인가하여 출력 특상과 전달특성을 분석하였는데, 그 결과 다결정 실리콘 박막 트랜지스터의 전달특성은 게이트 와 드레인 전압에 의존하는데 임계전압은 긴 채널길이와 좁은 채널 폭에서 높고 출력특성은 갑자기 높은 드레인 전류가 흐른다. 전기적 스트레스가 인가된 소자는 드레인 전류를 감소시킨다. 결국 전계효과 이동도는 긴 채널길이와 좁은 폭의 채널에서 더 빠른 것을 알 수 있다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.9
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• pp.47-53
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• 2011

The signal transmission properties of the connector such as insertion loss and return loss are investigated using analysis procedure of S-parameter simulation, equivalent model extraction, and characteristic impedance calculation. S-parameter simulation is performed by connector's modeling and solving based on 3-dimensional finite element method. The connector's equivalent model of ${\pi}$ type is are proposed and extracted with an optimization process of circuit analysis simulator. The characteristic impedance of the connector is calculated with results of circuit analysis simulation and S-parameter data. According to the connector's characteristic impedance, it's revised design is carried out. In this work, the connector's effective contact area is increased and its body is applied as a high dielectric material in order to increase its capacitance and then obtain impedance matching. Therefore, return loss of the connector is improved by approximately 10 dB due to its design revision.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.06a
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• pp.175-176
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• 2017

본 논문은 신속하고 정확한 재난정보 전달을 위해 재난 데이터를 수집하여 다중매체 특성에 맞추어 재난정보를 만들고 관리하는 다중매체 멀티미디어 재난정보 생성 및 전달 서비스 플랫폼을 제안한다. 제안하는 플랫폼은 지진, 태풍 등의 재난에 대해 측정 데이터를 정부 기관 및 지방자치단체를 통해 수집하면 재난의 규모, 위치, 시간, 대응 정보를 포함하는 재난정보를 CATV(Cable Television), IPTV(Internet Protocol Television) 등 다중매체 특성에 따라 생성하여 다중매체에 전달함으로써, 국민을 대상으로 매체의 특성에 독립적으로 일관되는 재난정보를 신속하고 정확하게 전달할 수 있다. 제안한 플랫폼을 통해 신속하고 정확하게 전달된 대국민 재난정보를 통해 재난에 대한 신속한 대국민 대응이 가능하여 재난 피해를 최소화할 수 있다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.1
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• pp.96-101
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• 1986

The average heat transfer coefficient of 2-D impinging jet has been augmented as much as 60% on the wall with large-scale wavy roughness. The mechanism of this heat transfer augmentation is studied with emphasis on two primary flow structures in the impinging flow region by using either the surface floating method or the smoke-wire technique. They are the stream-wise vortex-like structure, which is characteristic to the impining jet, and the spanwise vortiecs associated with the flow separation around the roughness. The combined effect of these structures can effectively augment the heat transfer particularly in the downstream region where the teat transfer usually deteriorates consicerably.

• Journal of the Korea Concrete Institute
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• v.21 no.3
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• pp.303-310
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• 2009

CFRP(carbon fiber reinforced polymer) tendons can be used as an alternative to solve the corrosion problem of steel tendons. Material properties of CFRP tendons such as bond strength, transfer length, and development length should be determined in order to apply to concrete structures. First of all, in case of application for pretension concrete members with CFRP tendons, transfer length is an important factor. A total of 9 beams have been cast to determine transfer length and development length of domestic CFRP tendon in this paper. Test results revealed that transfer length of the prestressing 25% and 50% are 34D, 55D respectively. Also, transfer length has increased as the prestressing force has increased. A change was observed in transfer length of developed CFRP tendon after 9 weeks. ${\alpha}_t$ of developed CFRP tendon was 2.3 similar to the steel strand.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.10
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• pp.817-824
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• 2015

Experiments were carried out to investigate the flow and mass transfer characteristics of an orifice nozzle. Measurements of primary and suction flow rates, dissolved oxygen concentration, and electric power were obtained. Vertically injected mixed-jet images were captured by a direct visualization technique with a high speed camera unit. The mass ratio, volumetric mass transfer coefficient, and mass transfer performance were calculated using the measured data. As the primary flow pressure increases, the mass ratio decreases slightly, while the volumetric mass transfer coefficient and electric power increase. As the primary flow pressure increases and the mass ratio decreases, the mass transfer rate increases because of the fine bubbles and wider distribution of the bubbles.