• International Journal of Highway Engineering
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• v.14 no.1
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• pp.25-34
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• 2012

The rapid economic development induced the massive road constructions, becoming bigger and high-speed of the vehicles. However, it brings lots of social problems, such as air pollutions, traffic noise and vibration. Special concrete block for the base course of asphalt pavement is needed to decrease traffic noise such as tire's explosive and vehicles sound, applying Helmholtz Resonators theory to asphalt pavement. If it is applied to the area where it happens considerable noise such as a junction, the street of a housing complex and a residential street, it is one of alternative methods to solve the social requirements of noise problems. This research examines couple of laboratory tests for the sound absorption effect of the concrete block and the base concrete block for quiet pavement. The specimens, which is fixed hall-size, space, depth as the condition of this research, are analysed of noise reduction effect using different noise levels of vehicles. Judging from the analysis of test results with vehicle noise volume, measurement distance, a form and size of the hall using the base concrete block, the use of special concrete base and quiet asphalt surface showed a good alternative solution for decreasing traffic noise level, from 4dB to 9dB.

• Journal of Korean Society of Transportation
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• v.24 no.2 s.88
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• pp.139-145
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• 2006

This paper develops pedestrian fatality models capable of producing the probability of pedestrian fatality in collision between vehicles and pedestrians. Probabilistic neural network (PNN) and binary logistic regression (BLR) ave employed in modeling pedestrian fatality pedestrian age, vehicle type, and collision speed obtained from reconstructing collected accidents are used as independent variables in fatality models. One of the nice features of this study is that an iterative sampling technique is used to construct various training and test datasets for the purpose of better performance comparison Statistical comparison considering the variation of model Performances is conducted. The results show that the PNN-based fatality model outperforms the BLR-based model. The models developed in this study that allow us to predict the pedestrian fatality would be useful tools for supporting the derivation of various safety Policies and technologies to enhance Pedestrian safety.

• Toxicological Research
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• v.17 no.3
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• pp.225-234
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• 2001

The present study was conducted to investigate the effects of Korean red ginseng water extract (KRGWE) on developmental toxicity caused by the environmental estrogen bisphenol A (BPA) in Sprague-Dawley rats. fifty males successfully mated were randomly assigned to five experimental groups, 1.e., group I (vehicle control), group II (BPA 1000mg/kg), group III (KRGWE 400mg/kg), group IV (BPA 1000mg/kg & KRGWE 200mg/kg), and group V (BPA 1000mg/kg & KRGWE 400mg/kg). The test articles were administered by gavage to mated females from gestational days (GD) 1 through 20 (sperm vaginal lavage=day O). All females were subjected to caesarean section on GD 21 and their fetuses were examined for external, visceral, and skeletal abnormalities. In the group II, significant maternal toxic effects including suppressed body weight, decreased body weight gain during pregnancy, and reduced food consumption were observed in pregnant rats. The minimal developmental toxicity including fetal ossification delay was also found in fetuses. In addition, a tendency for increased pregnancy failure, increased pre-and postimplantation loss, and decreased fetal body weight was observed. However, no fetal morpho-logical abnormalities were seen in surviving fetuses at a dose level of 1000mg BPA/kg. On the other hand, the maternal toxicity and developmental toxicity found in the groups IV and V were comparable to those of the group II. There were no adverse signs of either maternal toxicity or developmental toxicity in the group III. These results showed that administration of BPA at a dose level of 1000mg/kg to pregnant rats resulted in significant maternal toxicity and minimal developmental toxicity, and that no protective effects on BPA-induced maternal toxicity and developmental toxicity were found by concomitant gavage dosing of KRGWE.

• Journal of Welding and Joining
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• v.28 no.4
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• pp.26-32
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• 2010

The purpose of this study is to evaluate the residual stresses at the multi-pass FCA weldment using the finite element analysis (FEA). In order to do it, an H-type specimen was selected as a test specimen. The variable used was in-plane restraint intensity. The temperature distribution at the multi-pass FCA butt weldment was evaluated in accordance with the relevant guidance recommended by the KWJS. The effective conductivity for the weld metal corresponding to each welding pass was introduced to control the maximum temperature below the vaporization temperature of weld metal. The heat flux caused by welding arc was assumed to be applied to the weld metal corresponding to welding pass. With heat transfer analysis results, the distribution of transverse residual stresses was evaluated using the thermo-mechanical analysis and compared with the measured results by XRD and uniaxial strain gage. In thermo-mechanical analysis, the plastic strain resetting at the temperature above melting temperature of $1450^{\circ}C$ was considered and the weld metal and base metal was assumed to be bilinear kinematics hardening continuum. According to the comparison between FEA and experiment, transverse residual stresses at the multi-pass FCA butt weldment obtained by FEA had a good agreement with the measured results, regardless of in-plane rigidity. Based on the results, it was concluded that thermo-mechanical FE analysis based on temperature distribution calculated in accordance with the KWJS’s guidance could be used as a tool to predict the distribution of residual stress of the multi-pass FCA butt weldment.

• Korean Journal of Veterinary Research
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• v.52 no.2
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• pp.89-97
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• 2012

Mycobacterial cell-wall skeleton (CWS) is an immunoactive and biodegradable particulate adjuvant and has been tried to use for immunotherapy. The CWS of Mycobacterium bovis bacillus Calmette-Guerin (BCG-CWS) was studied as an universal vaccine vehicle for antigen conjugation, to develop potentially effective and safe vaccine. Although a variety of biological activities of BCG-CWS have been studied, the effects of BCG-CWS on spleen cells are not fully elucidated. Using MTT assay and trypan blue exclusion test, we found that BCG-CWS significantly enhanced the viability and proliferation of cells. Multiple clusters, indicating proliferation, were observed in BCG-CWS-treated spleen cells and surface marker staining assay revealed that BCG-CWS promoted the proliferation of $CD19^+$ B lymphocyte rather than $CD4^+$ or $CD8^+$ T lymphocyte. In addition, BCG-CWS up-regulated the expression of anti-apoptotic molecules such as bcl-2, bcl-xL. BCG-CWS increased the surface expression of CD25 and CD69 as well as IL-2 production of spleen cells, suggesting increased activation. Furthermore, BCG-CWS enhanced the antigen-specific cell proliferation and interferon-gamma production of spleen cells. Taken together, these results demonstrate the immunostimulatory effects of BCG-CWS on spleen cells via multiple mechanisms, providing valuable information to broaden the use of BCG-CWS in clinical and research settings.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.11
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• pp.1071-1077
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• 2012

Low frequency noises(up to about 200 Hz) such as booming are mainly caused by particular modes, and in general the solutions may be found based on mode controls where conventional methods such as FEM can be used. However, at higher frequencies between 0.3~1 kHz, as the number of modes rapidly increases, radiation characteristics from structures, performances of damping sheets and sound packages may be more crucial rather than particular modes, and consequently the conventional FEM may be less practical in dealing with this kinds of structure-borne problems. In this context, so-called 'mid-frequency simulation model' based on FE-SEA hybrid method is studied and validated to reduce noise in this frequency region. Energy transmission loss(i.e. air borne noise) is also studied. A dash panel component is chosen for this study, which is an important path that transmits both structure-borne and air borne energies into the cavity. Design modifications including structural modifications, attachment of damping sheets and application of different sound packages are taken into account and the corresponding noise characteristics are experimentally identified. It is found that the dash member behaves as a noise path. The damping sheet and sound packages have similar influences on both sound radiation and transmission loss. The comparison between experiments and simulations shows that this model could be used to predict the tendency of noise improvement.

• Journal of Applied Biological Chemistry
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• v.62 no.4
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• pp.355-359
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• 2019

In vivo micronucleus tests were performed to investigate the mutagenic potential of 4-butylaniline and N-butylaniline, which are used in dye intermediates and organic intermediates respectively. Groups of 5 male ICR mice were treated with vehicle or 4-butylaniline for 2 consecutive days by oral gavage at concentrations of 0 (control), 64, 160, 400, and 1000 mg/kg. Statistically significant and dose-dependent increases were found for micronuclei frequencies in male mice (p <0.05). These results suggest that 4-butylaniline can induce genetic effects in the micronuclei of male mouse bone marrow cells. Based on the positive results obtained in cytogenetic analyses of somatic cells in vivo, Globally Harmonized System of Classification and Labelling of Chemicals Category 2 was assigned. N-butylaniline was administered for 2 consecutive days by oral gavage to male ICR mice at dose of 0 (control), 64, 160, 400, and 800 mg/kg. N-butylaniline tested negative for micronuclei induction in mice, although N-butylaniline was associated with micronucleus induction at the highest dose. Based on the negative results obtained for cytogenetic analyses of somatic cells in vivo, "Not Classified" was assigned.

• International Journal of Automotive Technology
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• v.5 no.1
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• pp.33-46
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• 2004

A finite element model development of a 50th percentile male cervical spine is presented in this paper. The model consists of rigid, geometrically accurate vertebrae held together with deformable intervertibral disks, facet joints, and ligaments modeled as a series of nonlinear springs. These deformable structures were rigorously tuned, through failure, to mimic existing experimental data; first as functional unit characterizations at three cervical levels and then as a fully assembled c-spine using the experimental data from Duke University and other data in the NHTSA database. After obtaining satisfactory validation of the performance of the assembled ligamentous cervical spine against available experimental data, 22 cervical muscle pairs, representing the majority of the neck's musculature, were added to the model. Hill's muscle model was utilized to generate muscle forces within the assembled cervical model. The muscle activation level was assumed to be the same for all modeled muscles and the degree of activation was set to correctly predict available human volunteer experimental data from NBDL. The validated model is intended for use as a post processor of dummy measurement within the simulated injury monitor (SIMon) concept being developed by NHTSA where measured kinematics and kinetic data obtained from a dummy during a crash test will serve as the boundary conditions to "drive" the finite element model of the neck. The post-processor will then interrogate the model to determine whether any ligament have exceeded its known failure limit. The model will allow a direct assessment of potential injury, its degree and location thus eliminating the need for global correlates such as Nij.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.2
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• pp.161-168
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• 2015

Recently, due to various environmental problems such as global warming, increases of international oil prices, exhaustion of resource, a paradigm of world automobile market is rapidly changing from conventional vehicles using internal combustion engine to eco-friendly vehicles using electric power such as EV, HEV, PHEV and FCEV. Generally, in order to measure fuel consumption and pollutant emissions of cars, chassis dynamometer tests are performed on various driving cycles before actual driving test. There are many driving cycles for performance evaluation of conventional vehicles. However, there is a lack of researches on driving cycle for EV. In this study, the urban driving cycle for performance evaluation of electric vehicles was developed. This study is composed of two parts. In the part 1, the urban driving cycle 'GUDC-EV(Gwacheon-city Urban Driving Cycle for Electric Vehicles)' was developed by using driving data, which were obtained through actual driving experiment, and statistic analysis with chronological table. In this paper part 2, in order to verify the developed driving cycle GUDC-EV, virtual EV platforms were configured and simulations were performed with actual driving data using In addition, simulation results were compared with existing driving cycles such as FTP-72, NEDC and Japan 10-15.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.1
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• pp.110-115
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• 2006

STSAT-2 is the first satellite which will be launched by the first Korean Space Launch Vehicle(KSLV). Ground station Baseband Control system(GBC) is now developed for STSAT-2. GBC has two functions. One is control data path between satellite control computers and ground station antennas(1.5M, 3.7M, 13M) automatically. The other is sending and receiving data between ground station and satellite. GBC is implemented by FPGA(Field-Programmable Gate Array) which includes almost all logic(for MODEM, PROTOCOL and GBC system control). MODEM in GBC has two uplink FSK modulators(1.2[kbps], 9.6[kbps]) and six downlink FSK demodulators(9.6[kbps], 38.4[kbps]). In hardware, STSAT-2 GBC is smaller than STSAT-1 GBC. In function, STSAT-2 GBC has more features than STSAT-1 GBC. This paper is about GBC structure, functions and test results.