![]() ![]() ![]() Besides, NORD2000 makes possible to package the external built-in software, such as Virtual Lab and 3D CAD program, by which real-like circumstance can be prepared. In this study we have chosen NORD2000, since it offers abundant directivity index and frequency data hence, adding various technical attributes which we face in various road conditions. Among these four models, HARMONOISE and NORD2000 have the directivity which defines the directional head of sound source. On their study, they considered newly developed models, such as HARMONOISE, Son Road model, NMPD-Routes-2008 and NORD2000. ![]() followed former comparison works to come up with an update. FHWA Traffic Noise Prediction Model, FHWA Traffic Noise Model, CoRTN, RLS90, MITHRA, STL-86 and ASJ-1993 were well compared in algorithm and propagation characteristics. In 2001, Steele presented a critical review of the traffic noise prediction models on electric computing. On the rapid development of information technique, many models based on computing process about noise prospect have emerged. Because these noise barriers can optimize their unique transparency as much as possible to secure enjoying the scenery, the demand for their installation is particularly increasing. A representative example of reflective noise barriers would be a transparent noise barrier, which are mostly used in places that require view, right of light and lighting. Combined noise barriers do merge sound-absorbing and reflective noise barriers to simultaneously decrease the noise absorption and insulation, and are usually installed in vicinities that require partial visibility. The visual obstruction, however, exerts a negative image as materials such as aluminum and galvanized sheet iron are mainly used. In case of sound-absorbing noise barriers, the soundproof effect is extraordinary since sound-absorbing materials are used and these are usually installed in residential areas and highways in the downtown region. There are sound-absorbing noise, reflective noise and combined noise barrier types. This facility has been installed by predicting the propagation characteristics of traffic noise generated from the road. Noise barrier, on the other hand as an effective method to control the traffic noise, has been used for decades to reduce noise from highway which affected nearby residents. Keywords: Curved-Type, Noise Barrier, Panel shape, Reflection noise, Sound Insulation Performance, Swelling-type The swelling-type showed a decrease of 0.7~1.2 dB, performing the best diminution effect among the tested noise barriers. ![]() The emitting noise was generated by 6-lane road and the patterned noise barriers had shown the reduction effects, especially in swelling and swelling with curved type for middle height dwellers, and the V-shaped screen type for higher elevation dweller. The reduction effects of reflected sounds were evaluated for swelling, swelling with curved, rectangular and V-shaped screen type barriers, compared to the planar panel. To achieve this, we have conducted simulation by which the effects of patterned screens of noise barrier on high-ways were investigated. To reduce reflection noise by transparent type barrier, modification can be made to the shapes on the front side and hence get effects by distortion of sound transmission. However, reflection from this type of barrier could annoy dwellers on the sides of the road. Transparent type noise barrier is a desirable facility since it provides a secure view to drivers and passengers. ![]()
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