• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.327-332
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• 2004

Leak noise is a good source to identify the exact location of a leak point of underground water pipelines. Water leak generates broadband noise from a leak location and can be propagated to both directions of water pipes. This sound propagation due to leak in water pipelines is not a non-dispersive wave any more because of the surrounding pipes and soil. However, the necessity of long-range detection of this leak location makes to identify low-frequency acoustic waves rather than high frequency ones. Acoustic wave propagation coupled with surrounding boundaries including cast iron pipes is theoretically analyzed and the wave velocity was confirmed with experiment. The leak locations were identified both by the acoustic emission (AE) method and the cross-correlation method. In a short-range distance, both the AE method and cross-correlation method are effective to detect leak position. However, the detection for a long-range distance required a lower frequency range accelerometers only because higher frequency waves were attenuated very quickly with the increase of propagation paths. Two algorithms for the cross-correlation function were suggested, and a long-range detection has been achieved at real underground water pipelines longer than loom.

• Journal of Environmental Science International
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• v.18 no.4
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• pp.389-400
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• 2009

In this research, we measured the number of lanes, distance, disposition of apartment that are affecting the road traffic noise to evaluate the current condition of G city's road traffic noise. We decide on a basis regarding an apartment price formation factor, and the apartment current price and the results that compared. To have a point scale, we set the maximum road traffic noise at a 8 lane road for 5 points, give 4 points for a 6 lane road, which has a $2.1{\sim}2.5\;dB(A)$ difference compared to a 8 lane road, give 3 points for a 4 lane road, which has a $5.2{\sim}5.5\;dB(A)$ difference compared to a 8 lane road, and set 2 points for a 2 lane road and lower. If we set the standard floor plan as horizontal and a living room facing the roadside, the horizontal and living room facing the opposite side of the road is 1 point because it differs by 14.1 dB(A), and the vertical is 3 points since the difference is 5.3 dB(A). If we make grades by the distance, making standard the fifth floor with little soundproof effect from apartment to road, we observe a measurement below 2.9 dB(A) at a distance of less than 10 m and 5 dB(A), decreased at a distance of 20 m. Therefore, 4 points were given for less than 10m, 3 points for $10{\sim}20\;m$, 2 points for more than 20 m as we can apply the effect of a decay distance of line sound source and the decrease in noise effects of more than 6 dB(A), 1 point for more than 40m, and 0 points for more that 80 m since it is negligible. 28 apartments got 0 points because there is no effect of road traffic noise from other apartments, and 50 apartments where only the road at one side effect them got $5{\sim}10$ points. 4 apartments (17-2, 6-3, 10-4, 3-3) received over 20 points. 15 cases showed a difference between developer price and resale price, and 11 cases (73%) among them showed the same trend (price increases with a low road traffic noise restriction factor point) with the point of road traffic noise restriction factor. 4 cases demonstrated the opposite trend, showing price increases with a high restriction factor point. Among the 4 cases, case numbers 2,6 and 9 appear to be more affected by the location factor (business district) than the road traffic noise restriction factor, and case number 1 appears to be affected by the building factor (openness and direction).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8933-8939
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• 2015

In this paper, we designed a multi humanoid robot control method for performing an exhibition that will maximize the efficiency and user convenience and implementation. In recent years, an increasing number of case and to take advantage of the robots in the field performances and exhibitions, plays, musicals, orchestra performances are also various genres. In concert with the existing small humanoid exhibition to source from outside by using a computer and MP3 player and play, while pressing the start button of communication equipment for the show to start the robot began performing with the zoom. Thus, due to the dual source and robot operation and synchronization does not work well is the synchronization of the start of the concert sound starting point of the robot and robot motion and sound are reproduced separately were frequently occurs when you need to restart the show. In addition, when the center of gravity or lose the robots who were present during the performance problems such as performance or intervene to restart the show. In order to overcome this, in this paper, Multi-small humanoid robot was designed to control the efficiency and the user of the GUI-based human interface S/W to maximize convenience, Zigbee communication to transmit a plurality of data in al small humanoid It was used. In addition, targeting a number of the small humanoid robot demonstrated the effectiveness and validity of the user's convenience by gender actual implementation.

• The Journal of the Acoustical Society of Korea
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• v.10 no.2
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• pp.52-60
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• 1991

Sound propagation in a sloping sea bed ocean environment demonstrates ray curvature in a direction parallel to the shoreline. The theoretical analysis of this shows that an ensonified region and a shadow region are formed, and their spatial extents depend on the spatial coordinates of source and receiver, a sloping angle and sourece frequency. The purpose of this experimental study using a sloping sea bed model is to check the theoretical prediction as a part of an ongoing investigation in the ocean environment. The sloping sea bed model used in this experiment had an ideal pressure-release boundaries and a sloping angle of $220.5{\circ}$ A single frequency signal and an impulsive signal were used as omnidirectional point sources. The spatial acoustic field characteristics in the across slope direction were measured using the former and the frequency dependent field characteristics in a specific point were obtained using the latter. It has been found that the analysis for the spatial extent of shadow zone and the frequency dependent field characteristics in the across slope direction, has a good agreement with the theoretical solution.

• Journal of Information Technology Applications and Management
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• v.26 no.5
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• pp.41-56
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• 2019

Recently great loss of life and property is occurring because of fire, natural disaster, earth quake, tsunami and so on. People spend 80~90% of their time indoor environment like office, supermarket, campus. Therefore Indoor navigation and guidelines system became so essential for most of all. Incase of emergency we must be careful earlier, in such a cases 5G kind of new technology may also cannot work. So immediate action and quick routing notification for guidelines and protection is the most. Considering this issue We proposed indoor evacuating guidance system based on microcontroller Wi-Fi board for Indoor APP using mobile. Focusing various kind of technology like, ok google, voice search APP we purposed node architecture based system. When we listen fire alarm while living inside the room. Then to be safe we connect with server and start Arduino UNO+IoT ESP8266 Wi-Fi shield version1-IoT module to store data in MySQL DB server. We make application to escape out from the building up-to the three exits giving information from source point to destination. Our program can send information to the users emergency location and situations. For this when the user get sound or vibration in their mobile device it indicate fire out near by. At that time we update message from Arduino to DB server for the fixed current position inside the building which give routing signal for that fire out location by changing values from 0 to 1. We have user in point 10 where user is near by. Later we detect Wi-Fi signal form Nodemcu as room of each floor and try to connect with user. Main purpose of this paper is to save life of people in short time and find out the shortest path up to nearest exits in the time of emergencies and rescue them.

• Fire Science and Engineering
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• v.32 no.4
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• pp.60-68
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• 2018

Due to the complicated plan structure of the apartment units and the improved room-to-room sound insulation performance, it is difficult to communicate and recognize the fire situation by emergency broadcast equipment. In this study, speech intelligibility was measured and analyzed for three types of apartment unit by emergency broadcast equipment on various measurement points. Simulations were also conducted to improve the speech intelligibility. As a result of field measurements 72, 84, and 101 Type were not satisfied with NFSC standard of 90 dBA at the point of 1 m distance from source. In addition, it was evaluated that 75 dBA and CIS 0.7 of NFPA standard was not satisfied at all measurement points except for the 72 Type at living room point with door opened condition. Based on the door opened condition of the bedroom, it satisfied the NFPA of 75 dBA and CIS 0.7 in each bedroom when more than 90 dBA was satisfied at the 1 m separation point provided in NFSC standard.

• International Journal of Highway Engineering
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• v.13 no.3
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• pp.111-119
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• 2011

The noise prediction model, KRON-2006, in South Korea has been developed for obtaining the average noise level. The model is based on an outdoor sound propagation method based on ISO9613 and ASJ Model-1998 and supports the analysis of the linear noise source, such as highway, for obtaining Leq. Because of that, the model can't obtain Lmax, Lmin from the time series noise profile based on traffic at every moment. In order to address this problem, the real time noise prediction model based on traffic simulation using GIS model and algorithm is proposed. It can predict the vehicle point noise level based on vehicle type, speed generated from traffic simulation by using headway and obtain Lmax, Lmin as integrating the noise profile generated from it at every moment. An evalution of the noise prediciton model using field measurements finds good agreement between predicted and measured noise levels at 1m, 8m, 15m from curb of the near side lane.

• Korean Journal of Agricultural Science
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• v.37 no.3
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• pp.435-449
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• 2010

Soils in the sloping uplands in Korea are subject to intensive land use with high input of agrochemicals and are vulnerable to soil erosion. Development of the environmentally sound land management strategy is essential for a sustainable production system in the sloping upland. This report addresses the status of upland agriculture and the best management practices for the uplands toward the sustainable agriculture. More than 60% of Korean lands are forest and only 21% are cultivating paddy and upland. Uplands are about 7% of the total lands and about 62% of the uplands are in the slopes higher than 7%. Due to the site-specificity of the upland, many managerial and environmental problems are occurring, such as severe erosion, shallow surface soils with rocky fragments, and loadings of non-point source (NPS) contaminants into the watershed. Based on the field trials, most of the sloping uplands were classified as Suitability Class III-V and the major limiting factor was slope and rock fragments. Due to this, soils were over-applied with N fertilizer, even though N rate was the recommendation. This resulted in decreases in yield, degradation of soil quality and increases in N loading to the leachate. Various case studies drew management practices toward sustainable production systems. The suggested BMP on the managerial, vegetative, and structural options were to practice buffer strips along the edges of fields and streams, winter cover crop, contour and mulching farming, detention weir, diversion drains, grassed waterway, and slope arrangement. With these options, conservation effects such as reductions in raindrop impact, flow velocity, runoff and sediment loss, and rill and gully erosion were observed. The proper management practice is a key element of the conservation of the soil and water in the sloping upland.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.2 no.1
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• pp.15-19
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• 1986

Our report refers to occidental vocal techniques from Greece until today. It is remarkable that even with poor anatomy knowledge, there were advices on styles given from very early periods, for both church and secular singing. During the 18th century, the names of "vox pectoris", "vox guturris" and "vox capitis" appear, nominations that somehow remain nowadays with great confusion about source of sound production and results of resonance. Vocal occidental styles developed different kinds of requirements from the singers, that had to adapt their vocal Possibilities to them. The same happened with "pop" song. Nowadays, all kinds of singers must have a conscious knowledge of its voice management to prevent vocal disturbances. We consider that the technique is the same, even when the singer has to sing Wagner, Debussy, Sconberg, Piazzola or Gershwin. The big changes occured at resonance levels, and because these different use of the vocal resonators the effects are quite different. In summary, the big differences on classical the effects are quite different. In summary, the big differences on classical and pop song are done on the different use of the resonators and its effects on the vocal tract. "Pop" singers, men and women, should be taught to use both registers, "modal" and "falsetto" to be able to reach the complete range of their songs without any harm to their larynxes. In our opinion, a good singing technique means that it could be adapted to every stylistic need. The same technique is adapted to the popular singer as well. The main difference lays on the use of resonators, pretty strong in the classic singer, weaken in the popular singer, on the volume and on the total extension of the voice. Breathing control, effortless emission and the use of "passage" at the right point should be taught to all singers, regardless of their style. (omitted)

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.3
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• pp.193-210
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• 1991

For the deckhouse or superstructure, attention is directed to the reduction of vibration from a human susceptibility point of view. The two basic requirements for obtaining a low vibration level in the accommodation are to ensure that excitation forces from propeller and/or main engine are small and to avoid resonance excitation of the hull and superstructure. In recent years increased attention has been directed towards the problems of vibration and noise in deckhouse, which have caused major problems with regard to the environmental quality in the living quarters for crews. Accordingly, in this paper, the characteristic of the vibration of deckhouse of fishing boat, of which the length/height ratio is also relatively high, are studied systematically with regard to the shape and modelling of deckhouse based on finite element method of 1-dimensional, 2-dimensional and 3-dimensional model. This study is divided into 4-part. 1st part is the global deckhouse vibration, 2nd part is the local deckhouse vibration, 3rd part consists of the estimation for stiffness of foundational support and 4th part is the application to TUNA LONG LINER of 416 ton class. For the global vibration analysis, the severity of the vibration depends on the longitudinal shear and bending stiffness of the deckhouse, on the vertical deckhouse support(fore, aft and sides). However, even if the design is technically sound, vibration problems may arise due to vertical or longitudinal hull girder or afterbody resonances. Author applied the method of this study to the analysis of, deep-sea fishing vessel of G.T. 416 ton class with relatively low height and long deckhouse, and investigated the vibrational characteristic of the fishing vessel with earlier structural feature. According to this investigation, the vibration, response of above vessel was confirmed of which main hull and deckhouse behave as one body. It is at the bottom of vibrational trouble which a accommodation part of the fishing vessel is raised, that is the local vibration for side wall, fore-aft wall and deck plate of deckhouse rather than thief fect of fore-aft vibration of deckhouse for above fishing vessel. and the resonance of main hull, deckhouse and driving system such as the main engine, propeller in exciting source is mainly brought up as the trouble.