• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.6
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• pp.175-180
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• 2001

Dynamic response localization of simple mistuned periodic structures is presented in this paper Mistuning in periodic structures can cause forced responses that are much larger than those of perfectly tuned structures. So mistuning results in the critical impact on high cycle fatigue of structures. Thus, it is of great importance to predict the mistuned forced response in an efficient way. In this paper, forced responses of coupled pendulum systems are investigated to identify the localization effect of periodic structures. The effects of mistuning and damping on the maximum forced response are examined. It is found that certain conditions of mistuning and coupling can cause strong localization and the localization becomes significant under weak damping. It is also found that the maximum forced response increases as the number of Periodic structures increases.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.469-475
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• 2004

The transient analysis of delaminated smart composite laminates is studied using an improved layerwise laminate theory. The theory is capable of capturing interlaminar shear stresses that are critical to delamination. The presence of discrete delamination is modeled through the use of Heaviside unit step functions. Stress free boundary conditions are enforced at all fee surfaces. Continuity in displacement field and transverse shear stresses are enforced at each ply level. In modeling piezoelectric composite plates, a coupled piezoelectric-mechanical formulation is used in the development of the constitutive equations. Numerical analysis is conducted to investigate the effect of nonlinearity in the transient vibration of bimodular behavior caused by the contact impact of delaminated interfaces. Composite plates with delamination, subject to external loads and voltage history from surface bonded sensors, are investigated and the results are compared with corresponding experimental results and plates without delamination.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1275-1280
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• 2016

This research is for the visualization of wooden cracking phenomena in the virtual world. Timber supplies has been traditionally used for buildings in the all over the world. Wood has a characteristic that is more prone to be influenced and distorted under the external environments compared with other materials like as stone and concrete. Many related researches say that moisture content change is a largest impact factor for the distortion and crack of timber supplies. This is the reason why we focus on the relationship between the moisture variations and the wood distortion, especially crack. In this research, it is mathematically explained that the diminutions of tensile strength caused by repeated contraction and expansion according to the moisture variations under the changes of weather. Finally, we suggest a way to visualize it for pine timbers.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.283-287
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• 2008

The heat released during the external frictional motion is a factor responsible for initiating energetic materials under all types of mechanical stimuli including impact, drop, or penetration. We model the friction-induced ignition of HMX, RDX and AP/HTPB propellant using the BAM friction apparatus and one-dimensional time-to-explosion apparatus whose results are used to validate the friction ignition mechanism and the deflagration kinetics of energetic materials, respectively. The ignition times for each energetic sample due to friction are presented.

• Journal of the Korea Safety Management & Science
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• v.17 no.3
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• pp.149-162
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• 2015

This study was conducted on young children safety helmet to prevent risk of head injuries from external shock. Young children helmet shall be easy to wear and use comfortably. But the young children helmet market in domestic has imported dependently and widely variations in quality because the euro product of high priced and the east asia product of low priced are selling at the same time. Therefore, this study surveyed children under 13 years of age and Married people and studies their actual state of wearing. Furthermore, this study is going to propese the improving wearing of helmet and the major points of quality of helmet and the problem by comparing and reviewing regulations of domestic and foreign.

• Journal of Information Processing Systems
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• v.17 no.2
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• pp.399-410
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• 2021

Aiming at the problem that complex external variables in natural scenes have a greater impact on facial expression recognition results, a facial expression recognition method based on two-stream convolutional neural network is proposed. The model introduces exponentially enhanced shared input weights before each level of convolution input, and uses soft attention mechanism modules on the space-time features of the combination of static and dynamic streams. This enables the network to autonomously find areas that are more relevant to the expression category and pay more attention to these areas. Through these means, the information of irrelevant interference areas is suppressed. In order to solve the problem of poor local robustness caused by lighting and expression changes, this paper also performs lighting preprocessing with the lighting preprocessing chain algorithm to eliminate most of the lighting effects. Experimental results on AFEW6.0 and Multi-PIE datasets show that the recognition rates of this method are 95.05% and 61.40%, respectively, which are better than other comparison methods.

• Textile Coloration and Finishing
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• v.31 no.2
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• pp.107-117
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• 2019

In case of pure rubber materials, the initial quality of the rubber materials would be excellent, however, the durability against external impact might be poor. In order to overcome the relatively low durability, textile cord could be employed with silicone rubber. We have studied the improvement of heat-resistant adhesion properties of silicone adhesives between silicone rubber and PET fibers by applying various conditions including dip solution recipe. The silicone rubber used was a platinum catalyst curing type and platinum catalyst type silicone adhesive was used as an adhesive to obtain an optimum adhesive force. Furthermore, the bonding mechanism between silicone and PET fiber was established.

• Journal of the Semiconductor & Display Technology
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• v.19 no.4
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• pp.34-38
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• 2020

In this paper, we implement a Dashcam system capable of shooting 360 degrees using a Raspberry Pi, shock sensors, distance sensors, and rotating camera with a servo motor. If there is an object approaching the vehicle by the distance sensor, the camera rotates to take a video. In the event of an external shock, videos and images are stored in the server to analyze the cause of the vehicle's accident and prevent the user from forging or tampering with videos or images. We also implement functions that transmit the message with the location and the intensity of the impact when the accident occurs and send the vehicle information to an insurance authority with by linking the system with a smart device. It is advantage that the authority analyzes the transmitted message and provides the accident handling information giving the user's safety and convenience.

• Food Science and Industry
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• v.50 no.4
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• pp.2-11
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• 2017

The external factors of global flavor market include the world economy, population growth, urbanization, consumer spending, raw material availability, pricing, and regulatory issues. And the internal factors as product pricing and technology development may lie the flavor house's competitiveness and cost considerations. In developing countries, rising preference for packaged food and beverages and increasing personal expenditures will drive demand for flavor market. Increasing consumer demand for natural products, driven in part by health concerns and a desire for transparency in labeling will impact the demand. The increasing demand for salt and sugar reduction will boost demand for flavors to maintain the overall taste. The use of quality and innovative flavors in the beverages and the multifunctional flavors has a positive influence on the global market. The global flavor industry has the presence of several drivers and positive trends, with its future expected to be promising.

• Journal of Ginseng Research
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• v.45 no.3
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• pp.363-370
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• 2021

As the largest organ in our body, the skin acts as a barrier against external stress and damages. There are various cell types of skin, such as keratinocytes, melanocytes, fibroblasts, and skin stem cells. Korean ginseng, which is one of the biggest distributions of ginseng worldwide, is processed into different products, such as functional food, cosmetics, and medical supplies. This review aims to introduce the functional role of Korean ginseng on different dermal cell types, including the impact of Korean ginseng in anti-photodamaging, anti-inflammatory, anti-oxidative, anti-melanogenic, and wound healing activities, etc. We propose that this information could form the basis of future research of ginseng-derived components in skin health.