• Journal of the Korean Society for Precision Engineering
• /
• v.28 no.10
• /
• pp.1196-1203
• /
• 2011

Statistical optimum methodology of table of orthogonal array, ANOM, ANOVA and RSM are applied to formulate optimum allocation design with design variables. It can be minimized average SPL of control volume, the objective function in closed system by optimal allocated positions of absorbing material. Structural natural frequency and acoustic natural frequency of cavity are analyzed by FEM and BEM in the closed system. Using BEM, average SPL of specific control volume is calculated according to the condition before using absorbing material and after using it. It is shown that noise is reduced by $5.02dB_{RMS}$ by absorbing material located at optimal position and minimum $1.83dB_{RMS}$ and maximum $3.47dB_{RMS}$ by the table of orthogonal array.

• Journal of the Korea Society of Computer and Information
• /
• v.28 no.12
• /
• pp.97-104
• /
• 2023

In this paper, we propose a harmful bird repellent system using directional speakers. Existing sound systems for the extermination of harmful birds have the disadvantage of reducing effectiveness due to the learning effect of birds due to problems caused by noise pollution and monotonous sounds. In this paper, directional speakers are used to minimize surrounding noise. In addition, the up-down and left-right angles of the speaker driving device were freely adjusted to maximize usability. Additionally, the problem of performance degradation due to learning effects was solved by using various scanning patterns. In the future, we plan to develop a platform capable of central control by applying remote control functions and a deep learning model that can recognize bird species.

• Proceedings of the KIPE Conference
• /
• 1996.06a
• /
• pp.80-84
• /
• 1996

A Switched Reluctance Motor(SRM) has a torque pulsating inherently due to characteristics of pulse driving. A torque pulsating causes noise and sound vibration. To reduce a noise, a torque pulsating shall be controlled. Many efforts to make flat-topped current has been proposed to minimize a torque pulsating up to now. This paper proposed a control scheme to minimize the vibration of SRM by controlling the vibration directly by using of self-turning technique. The experimental results show that the proposed control scheme is effective in reducing the torque ripple and noise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1996.10a
• /
• pp.56-64
• /
• 1996

In this paper, the sound radiation level of parts of a O.B. Motor was measured and analyzed by the measurement method using wave-guide reverberation environment. Based on the above measurement results, a noise control was established for engine cover and exhaust silencer and its effects were compared and analyzed. The noise control method increased transmission loss by painting GELNAC on the engine cover and extend exhaust pipe to reach under water.

• Fashion & Textile Research Journal
• /
• v.14 no.4
• /
• pp.641-647
• /
• 2012

This study investigates the sound properties of fabric frictional sound (SPL, ${\Delta}L$, ${\Delta}f$) according to the film type of PTFE laminated vapor-permeable water-repellent fabrics in order to understand the relationship between SPL and the basic properties of fabrics such as layer, yarn type, and thickness of fiber. This study accesses their mechanical properties and determines how to control them to minimize SPL. Eight PTFE laminated water-repellent fabrics, composed of four different film types (A, B, C, D) and with two different fabrics, were used as test specimens. Frictional sounds generated at 1.21m/s were recorded by using a fabric sound generator and SPLs were analyzed through Fast Fourier Transformation (FFT). The mechanical properties of fabrics were measured by KES-FB. The SPL value was lowest at 74.4dB in film type A and highest as 85.5dB in type D. Based on ANOVA and post-hoc test, specimens were classified into less Loud Group (A, B) and Loud Group (C, D). It was shown that SPL was lower when 2 layer (instead of 3 layer), filament yarn than staple, and thin fiber than thick were used. In Group I, shearing properties (G, 2HG5), geometrical roughness (SMD), compressional properties (LC, RC) and weight (W) showed high correlation with SPL however, elongation (EM) and shear stiffness (G) did with SPL in Group II.

• 한국HCI학회:학술대회논문집
• /
• 2009.02a
• /
• pp.1145-1149
• /
• 2009

In the 1960s, light art using neon or fluorescent lamp, etc and 'light and space art' appeared with kinetic art. Light art that is an extension of kinetic art tends to be digitalized art and focus on movement, while light and space art emphasizes psychological side and focuses more on phenomenal experience than movement itself. Light art generally tends to offer visual play, but light and space art offers not only visual play but also deep impression on audience's mind. In this paper, LED control method using sound and how color change influences people's mind are studied based on my works try to supplement shortcoming of light art. The main goal of my work is to make more effective and empathic interaction between audience and light in order to avoid cold and mechanical impressions that light art has. Based on its contents, this study seeks method to stimulate people's emotion, and suggests applying mentality on the color and sound interaction together to media art. In conclusion, it is believed that new model of media art is suggested through this study.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.17 no.6
• /
• pp.137-143
• /
• 2017

Facilities for pedestrian safety of the visually impaired are scarce on the walkway and crosswalk. Braille blocks are installed on the walkways and RF controlled signal lights and sound generators are installed on the crosswalk at the main intersection for the visually impaired. An RF remote control system using one frequency has a problem of simultaneously operating nearby signal lamps and sound generators at an intersection. In this paper, we develop the smart cane that uses a beacon to identify the signal lamp and sound generators installed on the crosswalk at intersections and to operate the signal lamps and sound generators in the direction of the walk by IR communication. The developed smart cane is able to provide the pedestrian navigation for the blind by interworking with mobile apps through Bluetooth communication.

• The Journal of the Korea Contents Association
• /
• v.10 no.4
• /
• pp.91-97
• /
• 2010

Recently, Internet users have an interest about Social Media Service in Web2.0 environment. We suggest the orchestra service as social media service to meet user satisfactions in changed web environment. We accept a concept of the MMMD (Multiple Media Multiple Devices). In other words, Internet users listen to the music not only one device but multiple devices. Each one of multiple devices can play a sound source under earmark instruments for providing users with actual feeling like an orchestra. To meet the purpose, we define 3 steps. First, we separate the sound source based on instrument information. Second, we exact the suitable sound source for play orchestra. In final step, the sound source transmits to each suitable playing device. We named the 3 step for AET process. Beside we suggest synchronization method using rest point in the MIDI file for control sound sources. Using the AET process and synchronization method we provide the orchestra service for meet user's satisfactions to users.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.6 no.5
• /
• pp.703-708
• /
• 2011

In this paper, most of the church except for a large church has accommodated many audience to install a balcony floor in a small space. therefore, dead zone and dislocated sound image localization is made due to this under-balcony seats. This paper propose that the problems of dead zone and dislocated sound image localization could be solved using computer simulation in the view of practical side. The economical computer simulation tool, Mapp online that can be found easily was used to the specified church. Installation a sub speaker for dead zone and -10 dB power control of the sub speaker to main speaker power for dislocated sound image localization was proposed. Computer simulation result shows that the value of definition for area was improved from "Normal" to "Very Good" which means about 52% improvement.

• Corrosion Science and Technology
• /
• v.6 no.5
• /
• pp.219-226
• /
• 2007

Pre-construction primer (PCP), or shopprimer, have been applied to steel plates to control temporary corrosion during ship fabrication. For surface preparation at ship block stage, in common shipyard practices, welding beads, burnt and rusted areas shall be blasted or power tool cleaned and the contamination such as zinc salt shall be removed with blasting or power tool. Whereas, the sound film of PCP needs not to be removed or roughened as the paint having good compatibility with PCP is used for the first coat. In many cases, however, full blasting or sweep blasting on the sound PCP treated block assemblies was requested. There still has been argument about the legitimacy of this practice, thus, it is critical to evaluate the quality of the coating system applied on the sound PCP retained condition, comparing with the one applied on the full blasted or sweep blasted condition. In this study, two different epoxy systems for water ballast tank were applied on the surfaces with sound PCP condition, full blasted condition, and sweep blasted condition. Coating performances such as durability, anti-corrosion, cathodic disbondment resistance were evaluated. The test results clearly indicated that the sound film of PCP needed not to be removed or roughened as the paint having good compatibility with PCP based on inorganic zinc silicate.