• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.5
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• pp.46-53
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• 2017

This paper deals with an acoustic model for a lean premixed gas turbine combustor composed of three stages: premixing chamber, nozzle and flame tube. Our model is given as an acoustic transfer function whose input is a heat release rate perturbation and output is a velocity perturbation at a flame location. We have shown that the resonance frequencies are functions of three round-trip frequencies of acoustic wave in each stage, and area ratios between stages. By analyzing poles of the acoustic transfer function, we could characterize resonant frequencies and their dependency on various system parameters of a combustor. It was found that our analytic findings match with existing numerical and experimental results in literature.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.439-444
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• 2007

정서 전달에는 언어적 의사소통뿐만 아니라 비언어적 의사소통이 거론되곤 한다. 하지만 지금까지의 비언어적 의사소통 연구는 대부분 언어의 음향학적 연구나 얼굴표정 연구에 국한되었다. 또한 음악의 정서에 대한 연구는 음악적 구조 혹은 스타일과 여러 성격적 특질 및 행동 간의 관계, 혹은 생리적 효과 등 어떤 음악(what music)이 특정한 효과를 일으키느냐에 중점을 두고 있었다. 따라서 본 연구에서는 Gabrielsson & Juslin(1996)의 연구에 의거, 음악을 통하여 작곡가가 아닌 연주자의 의도된 정서가 청자에게 얼마나 잘 지각될 수 있는지 알아보고자 하였다. 봉 녕구의 가설은 다음과 같다; 첫째, 연주자의 정서적 의도는 음악의 모든 물리적 변인에 영향을 준다; 둘째, 청자는 의도된 정서를 지각하는 데 일반적으로 성공적이다; 셋째, 특정 정서는 다른 정서보다 더 잘 구분된다. 본 연구에 사용된 곡은 학습 효과를 배제하기 위하여 새롭게 전문 작곡가에 의해 작곡되었으며, 전문 연주자는 동일한 곡을 7종류의 정서(행복한, 슬픈, 화난, 두려운, 다정한, 엄숙한, 정서 표현 없음)를 표현하도록 연주하였다. 하나의 완전한 음악을 표현하기 위하여 각 곡은 멜로디(악기구성: 일렉트릭 기타, 베이스, 그랜드 피아노)와 리듬(드럼)을 포함하였다. 실험참가자는 각 곡을 듣고 7개의 정서 종류 각각에 점수를 평정하였다. 그 결과 이전 연구와 마찬가지로 청자는 연주자의 의도된 정서를 일반적으로 지각하는 데 성공하였으며 7개의 정서 중 특징적인 정서("행복한", "슬픈", "화난", "다정한") 는 다른 정서 보다 더 잘 구별되었다. 본 연구에 사용된 "두려운" 정서 곡의 음향분석 결과 소리 강도의 큰 변산이 특징이었다. 이는 이전 연구에서 "두려운" 정서의 특징인 타이밍의 큰 변산과 함께, "두려운" 정서가 '불규칙적이거나 변화가 커서 예측하기 어려운' 속성을 지니고 있음을 시사한다. 또한 "다정한" 정서에 대해서 본 연구에서는 다른 모든 정서와 유의미한 차이를 보인 반면, 이전 연구에서는 "슬픈"과 유의미한 차이가 없었다. 이는 본 연구에 쓰인 "다정한" 정서의 곡은 리듬 패턴을 다른 정서 버전과는 다르게 보사노바 리듬을 사용하였다. 이전 연구와는 다르게 빠른 템포였음에도 불구하고 구별이 잘 된 이유는 이와 같이 장르 특징적인 영향이 컸기 때문이라고 할 수 있다. 이는 연주자나 음악 스타일 자체의 성격이 정서 판단에 있어 큰 영향을 준다는 사실을 시사한다. 종합적으로 음악을 통한 정서 전달에 있어 연주자, 청자, 악기, 음악 스타일의 차이가 영향을 줄 수 있다는 사실을 확인하였으며 이러한 결과는 Scherer & Oshinsky(1977)가 언급하였듯 음악 연주가 다른 비언어적 의사소통 방법과 공유하는 특징이 있음을 시사한다.

• The Journal of the Acoustical Society of Korea
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• v.35 no.5
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• pp.375-382
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• 2016

This paper presents the results for the performance improvement of underwater communication in a passive time reversal mirror (PTRM) using ray-based blind deconvolution (RBD). In conventional PTRM, the signal to be recovered is found from matched-filtering the received probe signal. However, the communication performance is degraded because the time-varying impulse response for each data frame is not reflected in the received probe signal. In this study, the time-variant transfer function is estimated from each received data frame using RBD, and the estimated time-variant transfer function is then used to recover the data signal using PTRM. The results from the experimental data show that the suggested method improves the communication performance when comparing with the conventional PTRM.

• The Journal of the Korea Contents Association
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• v.16 no.4
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• pp.624-633
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• 2016

Although a number of information is emerging in the big data era and studies on the infographic studies for delivering it effectively are becoming an issue, the visualization study on the numerical information delivered through the credit card statement is very poor compared to its importance. The effective visualization method following each information characteristics was by analyzing the numerical information types focusing on the credit card statement. The type of the figure information classified into the comparative analysis, progress of time change, proportion, relationship, scope, and distribution, and it was made into the graph form proper to the nature of each information to study the most effective and ideal visual form. Therefore, this study is significant because it suggests a control point of the visualization by pointing out an effective visual form for delivering the numerical information that appears on the credit card statement with the figure characteristics.

• Journal of Korean Society of Steel Construction
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• v.14 no.4
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• pp.481-487
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• 2002

Currently, the load transfer's mechanism from a beam to a column has yet to ve clarified in a concrete filled steel tubular (CFT) structure with a connection type of an exterior diaphragm. The loads for each floor are transferred to the concrete core from a steel beam through ha contacted face between an in-filled concrete and the interior surface of a steel tube. Thus, a Push-Out test was performed to investigate the load transfer mechanism. A total of 30 samples were tested to confirm the bond stress and/or axial load distribution between a steel tube and in-filled concrete for CFT column. The main parameters considered for this study included concrete type, steel tube-shape/length, and the effect of a weld joint wit ha backing strip for a column splice. Test results were summarized to confirm load transfer behavior between a concrete and steel tube for each experimental parameter, using the analytical approach to verify experimental results.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.2
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• pp.211-218
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• 2020

The radio wave propagation characteristics of the transmitter and receiver position change in the indoor environment were predicted through simulation, then the results obtained through the transmission loss measurement were compared and analyzed with the simulation results. The conference room was chosen as the environment for measuring transmission loss, and the radio transmission characteristics of the two environments were compared by selecting the exhibition hall without interior decorations and fixtures. In each indoor environment, the position of the transmitter chose two cases. One located in the center of the front wall and the other in the center of the side wall, and the position of the receiver moved along the centerline of the conference room and the side wall, measuring the receiving power. For each change in transmitter-receiver position, received power of 3GHz and 6GHz band were measured and compared with the simulation forecast results. The changes in received power at each receiving point were analyzed according to the location of the transmitter and the frequency band variation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3B
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• pp.311-317
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• 2009

The traditional network anomaly detection systems execute the threshold-based detection without considering dynamic network environments, which causes false positive and limits an effective resource utilization. To overcome the drawbacks, we present the adaptive network anomaly detection model based on artificial immune system (AIS) in centralized network. AIS is inspired from human immune system that has learning, adaptation and memory. In our proposed model, the interaction between dendritic cell and T-cell of human immune system is adopted. We design the main components, such as central node and router node, and define functions of them. The central node analyzes the anomaly information received from the related router nodes, decides response policy and sends the policy to corresponding nodes. The router node consists of detector module and responder module. The detector module perceives the anomaly depending on learning data and the responder module settles the anomaly according to the policy received from central node. Finally we evaluate the possibility of the proposed detection model through simulation.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.6
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• pp.67-86
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• 2009

In this study, a 3D transmitting boundary in water-saturated transversely isotropic soil strata has been developed based on u-w formulation for application to general 3D analysis. Behavior in the far field region is expanded in the Fourier series, and dynamic stiffness for each term is obtained based on the u-w formulation. Transformation of the dynamic stiffness is presented to combine the transmitting boundary with the 3D finite elements for the near field region formulated in a 3D Cartesian coordinate system. The developed transmitting boundary is verified through a comparison of the dynamic behavior of a rigid circular foundation with the results from the existing numerical method. In addition, the developed transmitting boundary is applied to the analysis of the dynamic behavior of rigid foundations of diverse shapes, and the effects of the level of the groundwater table on the dynamic stiffness of a rigid rectangular foundation in the water-saturated transversely isotropic layered stratum are studied.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.98.1-98.1
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• 2015

G-M극저온냉동기의 구동으로 인해 발생되는 크라이오 펌프의 진동 저감을 위해 각 요소에 해당하는 부품의 소재 및 모델 변경으로 설계에 반영하고자 한다. G-M극저온냉동기는 헬륨냉매를 사용하여 2개의 정압과정과 2개의 정적과정으로 구성되는 냉동사이클을 구성하는데, 구조적 특성상 내부 왕복기의 운동과 고저압변환에 따른 압력차이가 냉동기의 진동을 유발하므로 진공성능에 영향을 줄 수 있으므로, 이를 최소화하는 기술 개발이 필요하다. 헬륨냉매의 고압 유동에 따른 관로 압력증가로 인한 유동소음이 발생하는데, 이로 인한 소음을 줄이기 위해 관로의 최적화 설계/방진구조반영(DAMPER)으로 진동 안정화(Vibration Stabilization)설계를 수행 하고자 하며, 이에 따른 최적화 연구을 수행하고자 한다. 일차적으로, 기존 시스템의 진동측정을 통해 진동의 가진원을 밝히고 진동 전달경로를 파악하고자한다. 진동 가진원의 가진 최소화, 진동전달경로의 전달률 최소화, 고압유동에 따른 관로 설계 최적화를 진동해석, 탄성체 동역학해석, 그리고 유동해석을 통해 진동 및 소음의 최소화 방안을 도출하고자 한다. 해석결과를 토대로 진동가진원의 최소화를 위한 제품설계변경과 진동전달경로에 대한 방진을 위한 dmper 적용(전달률 최소화) 및 유동소음 최소화를 위한 damper나 관로 최적화 설계를 수행한다. 상기 기존시스템 측정/분석, CAE해석을 통한 진동/소음의 최적화방안도출 및 실제품 적용기술은 저진동 크라이오펌프 개발을 위한 기반 기술 확립에 크게 기여할것이며, 향후 크라이오펌프 고도화 및 최신 기술 제품 개발에 큰 기여가 기대된다.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.2
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• pp.267-275
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• 2012

In this study, normal wind load and blast wind load are modeled mathematical. And the periodical torque and bending moments transmitted to the main shaft of wind turbine are investigated. A normal wind model assumed, of which the wind velocity is increased according to the height from ground. The average values and the harmonic terms of the transmitted moments are studied on the wind direction of range $-45^{\circ}{\sim}45^{\circ}$ and the bending moment characteristics are examined, which is regarded as the main source of the misalignment of gear train. In normal wind load case, excitation frequency is 3X (X : Rotor speed). When the wind direction is $+22.5^{\circ}$, the horizontal axis of bending moment occur the 50% of main torque. This result leads to edge contact of gear teeth by shaft elastic deformation. In blast wind load case, excitation frequency are 3X,6X,9X. Additional, in the (+) direction of wind load, relative harmonic percentage is increase.