• 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.

• Asian Spine Journal
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• v.12 no.6
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• pp.998-1009
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• 2018

Study Design: Olfactory ensheathing cells (OECs) from rat olfactory mucosa were cultured, characterized, and transplanted into a rat model of spinal cord injury (SCI). Purpose: To evaluate different doses of OECs in a rat model of SCI. Overview of Literature: SCI causes permanent functional deficit because the central nervous system lacks the ability to perform spontaneous repair. Cell therapy strategies are being explored globally. The clinical use of human embryonic stem cell is hampered by ethical controversies. Alternatively, OECs are a promising cell source for neurotransplantation. This study aimed to evaluate the efficacy of different doses of allogenic OEC transplantation in a rat model of SCI. Methods: OECs were cultured from the olfactory mucosa of Albino Wistar rats; these cells were characterized using immunohistochemistry and flow cytometry. Rats were divided into five groups (n=6 rats each). In each group, different dosage ($2{\times}10^5$, $5{\times}10^5$, $10{\times}10^5$, and >$10{\times}10^5$) of cultured cells were transplanted into experimentally injured spinal cords of rat models. However, in the SCI group, only DMEM (Dulbecco's modified Eagle's medium) was injected. Rats were followed up upto 8 weeks post-transplantation. The outcome of transplantation was assessed using the Basso, Beattie, Bresnahan (BBB) scale; motor-evoked potential studies; and histological examination. Results: Cultured cells expressed 41% of p75NTR, a marker for OEC, and 35% of anti-fibronectin, a marker for olfactory nerve fibroblast. These cells also expressed $S100{\beta}$ and glial fibrillary acid protein of approximately 75% and 83%, respectively. All the transplanted groups showed promising BBB scores for hind-limb motor recovery compared with the SCI group (p<0.05). A motor-evoked potential study showed increased amplitude in all the treated groups compared with the SCI. Green fluorescent protein-labeled cells survived in the injured cord, suggesting their role in the transplantation-mediated repair. Transplantation of $5{\times}10^5$ cells showed the best motor outcomes among all the doses. Conclusions: OECs demonstrated a therapeutic effect in rat models with the potential for future clinical applications.

• Journal of Environmental Science International
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• v.16 no.7
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• pp.823-830
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• 2007

Traffic noise is a kind of noise caused by cars, trains and aircraft. Among them, noise produced by cars is the most important factor in cities. According to the National Institute of Environmental Research(NIER)'s survey, Road traffic noise levels in Susan are the highest of all the cities in Korea. So, appropriate measures for road traffic noise reduction is required. For this purpose, the construction of a noise map in Susan will playa vital role. However, road traffic noise formulas are constructed considering regional characteristics such as each country road's environment and vehicle quality. Therefore, prior to constructing a noise map in Susan, examination processes about each formula constituent status and estimation process are required preferentially. In this research, the basic first stage is to estimate Susan's road traffic noise. First, investigate characteristics of each road traffic noise estimate and using this, a noise map is constructed for road traffic noise in Susan. Then the adaptation of a road traffic noise formula is evaluated.

• Asian Spine Journal
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• v.12 no.6
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• pp.1092-1099
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• 2018

Study Design: In-vitro biomechanical investigation. Purpose: To evaluate the biomechanical effects of the degeneration of the biodegradable cervical plates developed for anterior cervical discectomy and fusion (ACDF) on fusion and adjacent levels. Overview of Literature: Biodegradable implants have been recently introduced for cervical spine surgery. However, their effectiveness and safety remains unclear. Methods: A linear three-dimensional finite element (FE) model of the lower cervical spine, comprising the C4-C6 vertebrae was developed using computed tomography images of a 46-year-old woman. The model was validated by comparison with previous reports. Four models of ACDF were analyzed and compared: (1) a titanium plate and bone block (Tita), (2) strong biodegradable plate and bone block (PLA-4G) that represents the early state of the biodegradable plate with full strength, (3) weak biodegradable plate and bone block (PLA-1G) that represents the late state of the biodegradable plate with decreased strength, and (4) stand-alone bone block (Bloc). FE analysis was performed to investigate the relative motion and intervertebral disc stress at the surgical (C5-C6 segment) and adjacent (C4-C5 segment) levels. Results: The Tita and PLA-4G models were superior to the other models in terms of higher segment stiffness, smaller relative motion, and lower bone stress at the surgical level. However, the maximal von Mises stress at the intervertebral disc at the adjacent level was significantly higher in the Tita and PLA-4G models than in the other models. The relative motion at the adjacent level was significantly lower in the PLA-1G and Bloc models than in the other models. Conclusions: The use of biodegradable plates will enhance spinal fusion in the initial stronger period and prevent adjacent segment degeneration in the later, weaker period.

• Asian Spine Journal
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• v.12 no.6
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• pp.967-972
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• 2018

Study Design: Biomechanical study. Purpose: To investigate the relative stiffness of a new posterior pelvic fixation for unstable vertical fractures of the sacrum. Overview of Literature: The reported operative fixation techniques for vertical sacral fractures include iliosacral screw, sacral bar fixations, transiliac plating, and local plate osteosynthesis. Clinical as well as biomechanical studies have demonstrated that these conventional techniques are insufficient to stabilize the vertically unstable sacral fractures. Methods: To simulate a vertically unstable fractured sacrum, 12 synthetic pelvic models were prepared. In each model, a 5-mm gap was created through the left transforaminal zone (Denis zone II). The pubic symphysis was completely separated and then stabilized using a 3.5-mm reconstruction plate. Four each of the unstable pelvic models were then fixed with two iliosacral screws, a tension band plate, or a transiliac fixation plus one iliosacral screw. The left hemipelvis of these specimens was docked to a rigid base plate and loaded on an S1 endplate by using the Zwick Roell z010 material testing machine. Then, the vertical displacement and coronal tilt of the right hemipelves and the applied force were measured. Results: The transiliac fixation plus one iliosacral screw constructions could withstand a force at 5 mm of vertical displacement greater than the two iliosacral screw constructions (p=0.012) and the tension band plate constructions (p=0.003). The tension band plate constructions could withstand a force at $5^{\circ}$ of coronal tilt less than the two iliosacral screw constructions (p=0.027) and the transiliac fixation plus one iliosacral screw constructions (p=0.049). Conclusions: This study proposes the use of transiliac fixation in addition to an iliosacral screw to stabilize vertically unstable sacral fractures. Our biomechanical data demonstrated the superiority of adding transiliac fixation to withstand vertical displacement forces.