• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.719-723
• /
• 2002

The purpose of this study is to suggest the correlation of single-number ratings for sound insulation by floor impact. As a assessment method of impact sound insulation. we selected the IIC contour of ISO, A weighted sound level. Inverse A-weighting curve and L-Index of japanese industrial standard. And we estimated the single-number ratings by application the measured data of impact sound level to each method. The results showed that the coefficients of determination between each two single-number ratings were very high (more than 0.9169). And In the condition of same assessment method, the coefficient of determination for light-weight impact sound was higher than that for heavy-weight impact sound.

• International Journal of Aeronautical and Space Sciences
• /
• v.7 no.1
• /
• pp.129-136
• /
• 2006

A new guidance synthesis for anti-ship missiles to control impact angle and impact time is proposed in this paper. The flight vehicle is assumed as a 1st order lag system to consider more practical system. The proposed guidance synthesis enhances the survivability of anti-ship missiles because multiple anti-ship missiles with the proposed synthesis can hit the target simultaneously. The control input to satisfy constraints of zero miss distance and impact angle, and the feedforward bias control input to control impact time constitute the guidance law. The former is from trajectory shaping guidance, the latter is from neural network. And particle swarm optimization method is introduced to furnish reference input and output for learning in neural network. The performance of the proposed synthesis in the accuracy of impact time and angle is validated by numerical examples.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.6 no.2
• /
• pp.217-224
• /
• 2002

This paper is proposed a reasonable method for determining the dynamic properties, the impact factors caused by traffic loads on highway bridges. In addition, the impact factors obtained in previous inspection reports were classified by the span length of the bridge, kind of bridge and type of bridge and the result of the impact factor was adjusted by a statistical method and presented problems. Also, the method for determining the impact factor using traffic load is proposed and the proposed method is compared with the specification code. The method estimating the impact factors due to the traffic loads can efficiently recognize the response of the structure by providing the impact factors and help to save the investigation cost, and also it can be used for the maintenance of structures using the usual test of bridges.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.14 no.9 s.90
• /
• pp.811-818
• /
• 2004

Impact sounds, such as those created by footsteps, the dropping of an object or the moving of furniture, can be a source of great annoyance in residential buildings. The character and level of impact noise generated depends on the object striking the floor, on the basic structure of the floor, and on the floor covering. This study base on the evaluate of isolation performance of impact sound according to the impact noise reduction methods. Reduction methods consist of four ways. First way is increase thickness of bare floor and other ways are using the soft coverings on the floor and ceiling assembles. Last way is make floating floor with shock absorbing materials.

• Elastomers and Composites
• /
• v.28 no.4
• /
• pp.283-292
• /
• 1993

The morphology and impact strength of alloys of high density polyethylene(HDPE) and nylon-6(PA) with modified $ethylene-{\alpha}-olefin$ copolymer(OCP) as compatibilizer and impact modifier were measured by the scanning electron microscope(SEM) and the notched Izod impact test(and the high rate impact test), respectively. HDPE is incompatible with PA and specimens obtained from simple mechanical mixing show the inferior properties. However, it was indicated that OCP played roles of not only impact modifier but also compatibilizer. High rate impact test results were different from those of the notched Izod impact test, but in both tests OCP was effective for HDPE/PA blends. From SEM observation, the size of the dispersed phase in alloys prepared with OCP is much smaller than that of alloys without OCP and the interfacial adhesion of alloys prepared with OCP is also better. Toughening mechanism of polymer blends was discussed by combining the morphology analysis with mechanical and thermal properties.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.162-167
• /
• 2004

The low velocity impact characteristics of composite laminate curved beams are investigated to increase damage tolerance and reduce the deflection. Drop weight impact tests of the composite curved beam were performed with respect to pre-load, then the damage after impact was measured by macrography. Also, finite element analyses were performed using ABAQUS to investigate the stress state of composite curved beam with respect to pre-load and impact. From the investigation, it was found that pre-load of the composite curved beams had much influence on impact damage of the curved beam, which showed good agreement with the experiment results.

• Industrial Engineering and Management Systems
• /
• v.15 no.1
• /
• pp.99-109
• /
• 2016

During the last two decades, impact factor has been widely used as a journal evaluation metric that differentiates the influence of a specific journal compared with other journals. However, impact factor does not provide a reliable metric between journals in different subject categories. For example, higher impact factors are given to biology and general sciences than those assigned to other traditional engineering and social sciences. This study initially analyzes the trend of the time series of the impact factors of the journals listed in Journal Citation Reports during the last decade. This study then proposes new journal evaluation metrics that adjust the impact factors across different subject categories. The proposed metrics possibly provides a consistent measure to mitigate the differences in impact factors among subject categories. On the basis of experimental results, we recommend the most reliable and appropriate metric to evaluate journals that are less dependent on the characteristics of subject categories.

• Journal of Environmental Impact Assessment
• /
• v.9 no.1
• /
• pp.47-59
• /
• 2000

The Environmental Impact Assessment(EIA) System has grown up as an adult today in Korea(ROK). It seems that we have only focused on the specific and technical aspects of the assessment without looking at the whole concept during the past 20 years. Thus we have accomplished quantitative growth but not qualitative development at all. This is the right time we should reconstruct the concept and move into the step for qualitative development. It is expected that the corpulence of the EIA system would be enlarged due to the introduction of integrated impact assessment system. It is necessary to introduce a newly designed method into the EIA methodology and improve the Environmental Impact Assessment based on in order to accomplish and manage more effective EIA system. To the conclusion, it is highly necessary to formulate a wholly new system which can be useful to improve the existing various systems and to follow the fundamental concept of EIA.

• Journal of the Korean Society of Mechanical Technology
• /
• v.13 no.1
• /
• pp.49-56
• /
• 2011

The neck injury occupies the most of injury that happened by the rear impact car accident. This study was analyzed about influence of the neck injury in low speed rear impact and car crash accident investigation. There is no neck injury in low speed side rear impact. On the other hand, there is initial neck injury symptom of 10 % but no long-term neck injury symptom in low speed offset rear impact. It appeared that the possibility of neck injury in low speed rear impact is low. For the more study about the neck injury, it should be evaluate the effects of the car body structure, frame structure and rear crash pattern.

• Smart Structures and Systems
• /
• v.23 no.2
• /
• pp.123-139
• /
• 2019

Impact forces induced by external object collisions can cause serious damages to civil engineering structures. While accurate and prompt identification of such impact forces is a critical task in structural health monitoring, it is not readily feasible for civil structures because the force measurement is extremely challenging and the force location is unpredictable for full-scale field structures. This study proposes a novel approach for identification of impact force including its location and time history using a small number of multi-metric observations. The method combines an augmented Kalman filter (AKF) and Genetic algorithm for accurate identification of impact force. The location of impact force is statistically determined in the way to minimize the AKF response estimate error at measured locations and then time history of the impact force is accurately constructed by optimizing the error co-variances of AKF using Genetic algorithm. The efficacy of proposed approach is numerically demonstrated using a truss and a plate model considering the presence of modelling error and measurement noises.