• Title/Summary/Keyword: Sound Simulation

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Application of Geographical Information System on Golf Course Design for Reduction of Environmental Impacts (지형정보시스템기법을 이용한 친환경적 골프코스 설계)

  • Joo, Young-Kyoo;Lee, Whal-Hee;Lee, Mu-Chun
    • Asian Journal of Turfgrass Science
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    • v.20 no.1
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    • pp.93-105
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    • 2006
  • The construction of golf courses has had adverse effects on the natural landscape and delicate ecosystem of Korea. Efficiency in planning and design was necessary to minimize the environmental impact of the original construction. However, the ordinal design methods have limited the data processing by the massive scale of the project of golf course development. Conventional design methods did not have a proper tool for alternative plans on pre-estimation of landscape destruction or minimizing of the environmental impact. Therefore, advanced computerized techniques need to be adapted for golf course design to solve the problems concerning the environmental impacts. Geographic information system (GIS) was applied on the process of geographical data input and analysis through the final outputs. Simulation works by the total database management enable the pre-investigation of the design In view of an assessment of environmental impacts. It is also possible to evaluate plans easily and propose the alternatives properly. Precise quantity calculation of engineering works by computer system should be guaranteed scientific, economic, and environmentally-sound.

Implementation of Virtual Environment System for Multi-joint Manipulator Designed for Special Purpose Equipment with Wearable Joystick used in Disaster Response (웨어러블 조작기 기반 재난·재해 특수 목적기계 다관절 작업기의 가상 환경 작업시스템 구현)

  • Cha, Young Taek;Lee, Yeon Ho;Choi, Sung Joon
    • Journal of Drive and Control
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    • v.17 no.3
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    • pp.33-46
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    • 2020
  • We introduce a piece of special-purpose equipment for responding to disasters that has a dual-arm manipulator consisting of six-axis multi joints, and a master-slave operating system controlled by a wearable joystick for intuitive and convenient operation. However, due to the complexity and diversity of a disaster environment, training and suitable training means are needed to improve the interaction between the driver and equipment. Therefore, in this paper, a system that can improve the operator's immersion in the training simulation is proposes, this system is implemented in a virtual environment. The implemented system consists of a cabin installed with the master-slave operation system, a motion platform, visual and sound systems, as well as a real-time simulation device. This whole system was completed by applying various techniques such as a statistical mapping method, inverse kinematics, and a real-time physical model. Then, the implemented system was evaluated from a point of view of the appropriateness of the mapping method, inverse kinematics, the feasibility for real-time simulations of the physical environment through some task mode.

Biomimetics of Nano-pillar (나노섬모의 자연모사 기술)

  • Hur, Shin;Choi, Hong-Soo;Lee, Kyu-Hang;Kim, Wan-Doo
    • Elastomers and Composites
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    • v.44 no.2
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    • pp.98-105
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    • 2009
  • The cochlea of the inner ear has two core components, basilar membrane and hair cells. The basilar membrane disperses incoming sound waves by their frequencies. The hair cells are on the basilar membrane, and they are the sensory receptors generating bioelectric signals. In this paper, a biomimetic technology using ZnO piezoelectric nano-pillar was studied as the part of developing process for artificial cochlea and novel artificial mechanosensory system mimicking human auditory senses. In particular, ZnO piezoelectric nano-pillar was fabricated by both low and high temperature growth methods. ZnO piezoelectric nano-pillars were grown on solid (high temperature growth) and flexible (low temperature growth) substrates. The substrates were patterned prior to ZnO nano-pillar growth so that we can selectively grow ZnO nano-pillar on the substrates. A multi-physical simulation was also conducted to understand the behavior of ZnO nano-pillar. The simulation results show electric potential, von Mises stress, and deformation in the ZnO nano-pillar. Both the experimental and computational works help characterize and optimize ZnO nano-pillar.

Design and Fabrication of an Implantable Microphone for Reduction of Skin Damping Effect through FEA Simulation (피부에 의한 이득 감쇠를 줄이기 위한 FEA 시뮬레이션 기반의 이식형 마이크로폰 설계 및 구현)

  • Han, Ji-Hun;Kim, Min-Woo;Kim, Dong-Wook;Seong, Ki-Woong;Cho, Sung-Mok;Park, Il-Yong;Cho, Jin-Ho
    • Journal of Biomedical Engineering Research
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    • v.29 no.1
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    • pp.59-65
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    • 2008
  • Nowadays, implantable hearing aids have been developed to solve the problems of conventional hearing aids. In case of fully implantable hearing aids, an implantable microphone is necessary to receive sound signal beneath the skin. Normally, an implantable microphone has poor frequency response characteristics in high frequency bands of acoustic signal due to the high frequency attenuation effect of skin after implantation to human body. In this paper, the implantable microphone is designed to reduce the high frequency attenuation effect of a skin by putting its resonance frequency at the attenuated range through a finite element analysis (FEA) simulation. The designed implantable microphone through the simulated results has been fabricated by manufacturing process using bio-compatible materials. By the several in-vitro experiments with pig skin, it has been verified that the designed implantable microphone has a resonance frequency around the starting part of the attenuated range and reduces the attenuation effect.

KTX Interior Noise Reduction Performance Comparison Using Multichannel Active Noise Control for Each Section (다중채널 능동소음제어기법을 이용한 KTX 실내소음의 구간별 저감성능 비교)

  • Jang, Hyeon-Seok;Kim, Young-Ming;Lee, Tae-Oh;Lee, Kwon-Soon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.1
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    • pp.179-185
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    • 2012
  • Since the eco-era is getting closer, the importance of noise reducing in the passenger cars of high-speed train is very important. The active noise control is best choice to reduce low frequency noise because the passive one is too heavy for high speed trains where weight is so critical. Also ANC is able to reduce the ambient noise when the environmental-factor changes. To reduce a three-dimensional closed-space sound field like a car of a high-speed rail is hard to do using single channel ANC control system. We used multi-channel FXLMS algorithm which calculation speed is fast and the secondary path estimation is possible in order to take into account the physical delay in electro acoustic hardware control loudspeaker and power amplifier. Firstly, we have measured interior noise of KTX and estimated noise path in KTX test-bed. However there was some problem related to algorithm divergence and increasing the filter order. We have made a simulation of interior environment of KTX car by using three frequency bands of 120Hz, 280Hz, 360Hz as the most important for KTX ANC system. During this research the interior noise reduction of KTX car was made by using the multi-channel FXLMS algorithm. Reduction performance was evaluated and compared each other for open space section and tunnel section. in-situ experiment for the KTX noise reduction by proposed ANC was performed based on data obtained in simulation and they were compared for open space section and tunnel section as well.

Detection Performance Analysis of Underwater Vehicles by Long-Range Underwater Acoustic Communication Signals (장거리 수중 음향 통신 신호에 의한 수중 운동체 피탐지 성능 분석)

  • Hyung-Moon, Kim;Jong-min, Ahn;In-Soo, Kim;Wan-Jin, Kim
    • Journal of the Korea Society for Simulation
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    • v.31 no.4
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    • pp.11-22
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    • 2022
  • Unlike a short-range, a long-range underwater acoustic communication(UWAC) uses low frequency signal and deep sound channel to minimize propagation loss. In this case, even though communication signals are modulated using a covert transmission technique such as spread spectrum, it is hard to conceal the existence of the signals. The unconcealed communication signal can be utilized as active sonar signal by enemy and presence of underwater vehicles may be exposed to the interceptor. Since it is very important to maintain stealthiness for underwater vehicles, the detection probability of friendly underwater vehicles should be considered when interceptor utilizes our long-range UWAC signal. In this paper, we modeled a long-range UWAC environment for analyzing the detection performance of underwater vehicles and proposed the region of interest(ROI) setup method and the measurement of detection performance. By computer simulations, we yielded parameters, analyzed the detection probability and the detection performance in ROI. The analysis results showed that the proposed detection performance analysis method for underwater vehicles could play an important role in the operation of long-range UWAC equipment.

Reflection - Transmission Type Inverse Scattering Ultrasonic Computed Tomography Using Cirucular Arc Linear Array Transducers (원호형 선배열 트랜스듀서를 이용한 빈사-투과형 역산란 초음파 토모그래피)

  • 김정순;하강열;산전황;김무준
    • The Journal of the Acoustical Society of Korea
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    • v.23 no.4
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    • pp.268-273
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    • 2004
  • A method of reflection-transmission type ultrasonic inverse scattering image was presented using linearly arrayed transducers in inner surface of half-cylinder. In this method, to reduce the number of data, the mirror effect using a reflector behind object and pulse wave with finite frequency band, To verify the proposed method, a computer simulation was performed for organic phantom specimen, As the results. it was verified that the reconstructed image was satisfactory even when the limitation view angle was limited to around 30 deg.

Suggestions for Energy Utilization Improvement of Fractionation and Hydrodealkylation Units Based on Exergy Analysis (엑서지 해석에 근거한 분별증류 및 수소첨가알킬제거 공정의 에너지 이용 개선 방안)

  • Chung, Yonsoo
    • Clean Technology
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    • v.12 no.2
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    • pp.95-100
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    • 2006
  • Fractionation and hydrodealkylation (HDA) units, subparts of BTX plant, were thermodynamically analyzed using the notion of exergy. Exergy values were calculated as the sum of physical and chemical exergies due to the existence of chemical reactions. The analysis was based on the simulation results with the aid of real operating data. Driving and material exergy losses were separately defined and quantified. Locations and the reason of major exergy losses were identified and improvement strategies were suggested. It was noted that the exergy analysis could provide a sound base for adopting the concept of industrial ecology and developing loss prevention schemes.

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Secondary Path Estimation Algorithm Based on Residual Music Canceller for Noise Cancelling Headphone (노이즈 캔슬링 헤드폰에 적합한 잔여 음악 제거기 기반의 2차 경로 추정 알고리즘)

  • Ji, Youna;Lee, Keunsang;Park, Youngcheol
    • The Journal of the Acoustical Society of Korea
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    • v.34 no.5
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    • pp.377-384
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    • 2015
  • An active noise control (ANC) algorithm for noise canceling headphone is proposed. In this study, the feedback ANC operated with the filtered-x least mean square algorithm (FxLMS) algorithm is used to attenuate the undesired noise. Also an adaptive residual music canceller (RMC) is proposed for enhancing the accuracy of the reference signal of the feedback ANC. Simulation results show that a high quality of music sound can be consistently achieved in a time-varying secondary path situation.

A Study on Stable Motion Control of Humanoid Robot with 24 Joints Based on Voice Command

  • Lee, Woo-Song;Kim, Min-Seong;Bae, Ho-Young;Jung, Yang-Keun;Jung, Young-Hwa;Shin, Gi-Soo;Park, In-Man;Han, Sung-Hyun
    • Journal of the Korean Society of Industry Convergence
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    • v.21 no.1
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    • pp.17-27
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    • 2018
  • We propose a new approach to control a biped robot motion based on iterative learning of voice command for the implementation of smart factory. The real-time processing of speech signal is very important for high-speed and precise automatic voice recognition technology. Recently, voice recognition is being used for intelligent robot control, artificial life, wireless communication and IoT application. In order to extract valuable information from the speech signal, make decisions on the process, and obtain results, the data needs to be manipulated and analyzed. Basic method used for extracting the features of the voice signal is to find the Mel frequency cepstral coefficients. Mel-frequency cepstral coefficients are the coefficients that collectively represent the short-term power spectrum of a sound, based on a linear cosine transform of a log power spectrum on a nonlinear mel scale of frequency. The reliability of voice command to control of the biped robot's motion is illustrated by computer simulation and experiment for biped walking robot with 24 joint.