• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.3
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• pp.28-33
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• 2018

The automotive front bumper guard is the most important part of the vehicle for protecting the life of driver when a traffic accident happens. In order to ensure safe driving, this part must possess sufficient strength and durability. This study was carried out with structural and fatigue analyses by designing front bumper guard models. After the lowest value for maximum total deformation and equivalent stress was found through structural analysis and the highest value for fatigue life was found for all three models, it was shown that the type C front bumper guard model was the most suitable for application to a real car. The strength property and durability of the optimum design were determined through this study's results.

• Structural Engineering and Mechanics
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• v.49 no.4
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• pp.509-521
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• 2014

In this paper two protocols of Wireless Sensor Networks (WSN) are examined through both a simulation and a case study. The simulation was performed with the optimized network (OPNET) simulator while comparing the performance of the Ad-Hoc on demand Distance Vector (AODV) and the Dynamic Source Routing (DSR) protocols. This is compared and shown with real-world measurement of deflection from eight wireless sensor nodes. The wireless sensor response results were compared with accelerometer sensors for validation purposes. It was found that although the computer simulation suggests the AODV protocol is more accurate, in the case study no distinct difference was found. However, it was shown that AODV is still more beneficial in the field as it has a longer battery life enabling longer surveying times. This is a significant finding as a large factor in determining the use of wireless network sensors as a method of assessing structural response has been their short battery life. Thus if protocols which enhance battery life, such as the AODV protocol, are employed it may be possible in the future to couple wireless networks with solar power extending their monitoring periods.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6441-6446
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• 2013

The smart phone is a representative personal device that can provide information onan individual's behavior related to real-life places, where the mobile phone users frequently stay and go, and the people who call or meet with the user. This paper proposes moving modeling that is based on the individual life logs using mobile phone data for identifying individuals. This method can be used to recommend the most suitable phone-service.

• Korean Parent-Child Health Journal
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• v.13 no.1
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• pp.8-16
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• 2010

Purpose: This study aimed to explore university students' views on a childbirth to gaining a deeper understanding of their individual thinking and the meaning that it hold for them. Methods: A Phenomenological approach was used. Subjects were 10 university students who go to university in D city. The method proposed by Colaizzi (1978) was used to guide the process of data analysis. Results: The formulated meaning were classified into nine themes. And then the nine themes were finally grouped into five theme clusters as follow: 'a smooth life', 'the law of nature', 'living a real life', 'fear and burden'. Conclusion: University students' views on a childbirth reflect with the run of the lower birth rate and the aging population in Korean society. Therefore, nursing interventions should be directed toward supporting their positive thinking and changing their negative thinking on childbirth.

• International Journal of Reliability and Applications
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• v.4 no.3
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• pp.113-129
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• 2003

Based on moments inequalities new testing procedures are derived for testing exponentiality against new renewal better than used (NRBU) and renewal new better than used (RNBU). These classes play an important role in formulating repair or replacement policies. The asymptotic Pitman efficiency of (NRBU) and (RNBU) testes are studied. Selected critical values are tabulated for sample sizes n=5(1) 50. The power estimates for some commonly used life distributions in reliability are also calculated. Some set of real data is used as an example to elucidate the use of the proposed test statistic for practical reliability analysis. The problem in case of right-censored data is also handled.

• Proceedings of the KIEE Conference
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• summer
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• pp.464-466
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• 2004

This paper proposes a method to consider an aging failure probability and survival probability of power system components unlike uses only aging failure probability in existing mean life calculation. The estimates of the mean and its standard deviation is calculated by using Weibull distribution and each estimated parameters is obtained from Data Analytic Method (Type II Censoring). The parameter estimation using Data Analytic Method is simpler and faster than a traditional calculation method. This paper shows how to calculate the mean life and its standard deviation by the proposed method and illustrates a exactness using real historical records of generator utilities in korea.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.2
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• pp.180-188
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• 1999

The objective of this paper is, based upon the principles of artificial life, to induce emergent behaviors of multiple autonomous mobile robots which complex global intelligence form from simple local interactions. Here, we propose an architecture of neural network learning with reinforcement signals which perceives the neighborhood information and decides the direction and the velocity of movement as mobile robots navigate in a group. As the results of the simulations, the optimum weight is obtained in real time, which not only prevent the collisions between agents and obstacles in the dynamic environment, but also have the mobile robots move and keep in various patterns.

• Journal of the Korean Society for Precision Engineering
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• v.2 no.3
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• pp.77-83
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• 1985

Adaptive control technique for a milling process is developed and implemented in an NC milling machine retrofitted to enable the micro-computer control. The control algorithm has the objects to guarantee the optimal tool life which can give the predetemined allowable lower limit of surface roughness. The experimental results show 1) that the extended tool life equation has good reliability in normal tool wear conditions. 2) and that the proposed adaptive control technique, which determine the optimal cutting condition by basing on the tool life equation modified continually according to the tool wear measured in real time, performs well.

• Journal of the Korean Wood Science and Technology
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• v.42 no.5
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• pp.563-570
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• 2014

Two transversely isotropic plasticity-based models for wood, derived from the standard compression properties and the embedment properties were investigated for suitability of application for bolted connections. It was found that the conventional connection models involving the compression properties were incapable of simulating the real behaviour of the connections because the compression properties provided too stiff foundation to represent embedding behaviour of wood under the bolt. However, wood foundation-based connection model that was newly developed using the bolt embedment properties showed good agreement with the actual behaviour of bolted connections.

• Journal of the Korean housing association
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• v.1 no.1
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• pp.37-48
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• 1990

The objective of this study is to suggest a housing life cycle of Korean families which adds to the establishment of reasonable housing standards and to the prediction of fufure-oriented family housing behavior by reviewing published papers. Following model is suggested as a housing life cycle suitable to assess the family housing behavior in Korea. 1st stage : period of house searching 2nd stage : period of house changing 3rd stage : period of house stabilizing \circled1 size enlargement phase \circled2 quality improvement phase \circled3 stable settlement phase 4th siage : period of house contracting 5th stage : period of house depending Since the proposed model is hypothetical, it must be tested and modified by the extensive social survey research on the real housing event history.