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Kwon K.,National University of Management | Cho J.,Dongyang Technical College | Park Y.,National University of Management
Expert Systems with Applications | Year: 2010

During the past few decades, the importance of personalization has been emphasized frequently in the field of e-services. Since there are various dimensions in the implementation of personalization, a variety of personalization strategies have been developed and embodied. Yet, little is known about the impact of different personalization dimensions on customer retention, which is the fundamental objective of personalization. This results in a lack of consensus about how best to characterize the personalization construct. In order to solve this problem, this study empirically investigates the effect of each classified personalization strategy and proposes the most highly recommended combination of personalization dimensions. © 2009 Elsevier Ltd. All rights reserved.

Cho S.,Dongyang Technical College | Chang T.-E.,Samsung | Lee J.Y.,Samsung | Park H.-P.,Korea Institute of Industrial Technology | And 2 more authors.
Microelectronics Reliability | Year: 2010

Printed Circuit Board (PCB) warpage increases as thickness decreases and ultimately is attributed to CTE mismatch and thickness geometry of the components. Recently, a thin Ball Grid Array (BGA) PCB has been developed due to the advantages like high electrical translation speed with low signal noise. Large warpage severely limited by BGA PCB performance leads to reliability issues modes such as crack and delamination between interconnection components. This is why a dummy design on a BGA PCB and metal stiffener on a Flip Chip (FC) BGA PCB warpage are analyzed experimentally. At the first step, new dummy design in BGA PCB (BoC type) is proposed to reduce warpage. The new dummy design is shaped as a bar. Results of the statistical experimental analysis show PCB warpage using the new dummy design is significantly reduced compared to the use of a PCB with a conventional dummy design. Furthermore, the new dummy design decreases PCB warpage by about 67%. These results signify that the stiffness of the BoC PCB is improved by the new dummy design because the bar-shaped Cu pattern in the dummy acts as a rigid bar stiffener. At the second step, metal stiffener effect is studied to reduce coreless FCBGA PCB warpage. Coreless FCBGA PCB, coreless FCBGA package, and specimens with non-symmetric structure are considered to determine metal stiffener effect on warpage. The experimental results show that metal stiffener has high stiffness, and it seems very effective on reducing average and standard deviation of coreless PCB warpage. © 2009 Elsevier Ltd. All rights reserved.

Kim B.-K.,Korea University | Hong S.-H.,Dongyang Technical College | Hur K.,Gyeongin National University of Education | Eom D.-S.,Korea University
IEEE Transactions on Consumer Electronics | Year: 2010

To synchronize clocks of nodes with low energy use and in short time in WSNs, this paper focuses on the reduction of the number of transmissions and on the message forwarding amongst sensor nodes. And we present a method, which is called EETS (Energy-Efficient Time Synchronization). The EETS method decreases the number of messages for the time synchronization and the messages could be rapidly passed through the network. Additionally, the WSNs are finally able to save energy. Through the performance comparisons of existing algorithms and the EETS with a network simulator and analysis, we show the performance evaluations of the EETS and the improved energy efficiency of the proposed algorithm for the Time Synchronization in the WSNs. © 2006 IEEE.

Chun I.,Electronics and Telecommunications Research Institute | Park J.,Dongyang Technical College | Kim W.,Electronics and Telecommunications Research Institute | Kang W.,Electronics and Telecommunications Research Institute | And 2 more authors.
International Conference on Advanced Communication Technology, ICACT | Year: 2010

Cyber-physical systems (CPS) are characterized by extremely tight integration of and coordination between computational and physical resources. Embedded computers and networks in the cyber world monitor and control the physical world. But it is impossible to make systems suitable to all situations because the physical world has much uncertainty and uncontrollable condition. The interactive mechanism between the cyber world and the physical world is a key domain for innovation and a major challenge to building Cyber-Physical systems. As the most application fields of CPS are the national infrastructure such as Smart Rescue System, Intelligent Building System, Smart Grid, Smart Highway and etc., all cyber-physical systems "must be dependable, secure, safe, efficient and operate in real-time. They must also be scalable, cost-effective and adaptive." [1) In this paper, we focus on the dependability of CPS to make high reliable systems.

Hong S.-H.,Dongyang Technical College | Kim B.-K.,Korea University
IEEE Transactions on Consumer Electronics | Year: 2010

In the future ubiquitous home network, sensors will collect various home environment data in the home. Since the sensor nodes are equipped with small, often irreplaceable, batteries with limited power capacity, it is essential that the network be energy-efficient in order to maximize its lifetime. Our study, described in this paper, was divided into two classes: The primary class was to set a gateway-selection level and the secondary class was to propose an offer of a home automation using a routing technique centered on a sensor network to set a flooding level. The proposed scheme is to increase the life time of the sensor network with the integrated gateway node. The IGN increases the life time of the network to integrate the multiple gateway nodes © 2006 IEEE.

PubMed | University of Wisconsin - Milwaukee and Dongyang Technical College
Type: Journal Article | Journal: Journal of sports science & medicine | Year: 2014

The use of wrist guards has limited efficacy in preventing wrist injuries during falling in many sports activities. The objectives of this study were to measure the ground reaction force of the hand under simulated impact of the forearm and hand complex with different padding conditions of wrist guards and to analyze their impact force attenuation and maximum energy absorption for improved functional efficiency. A total of 15 subjects, wearing a commercial wrist guard, participated in a cable-released hand impact experiment to test four different conditions on the volar aspect of the hand, which include a wrist guard without a volar splint (bare hand), with a volar splint (normal use), with a volar splint and additional viscoelastic polymeric padding, and a volar splint and additional air cell padding. The ground reaction force and acceleration of the hand were measured using a force platform mounted on an anti-vibration table and a miniature accelerometer, respectively. Additional padding on the bare hand could substantially improve the maximum energy absorption by more than 39%, with no differences with each other. However, only the air cell padding could simultaneously improve the impact force attenuation by 32% compared with the bare hand impact without compromising the maximum energy absorption. It is recommended that common wrist guard design should provide more compliant padding in the volar aspect to improve the impact force attenuation through optimal material selection and design. Key PointsTHE CONTROVERSIAL EFFICACY OF WRIST GUARDS IN PREVENTING WRIST INJURIES DURING FALLING WAS TESTED THROUGH INVESTIGATION OF THEIR IMPACT FORCE ATTENUATION AND MAXIMUM ENERGY ABSORPTION FROM THE MEASURED GROUND REACTION FORCE OF THE HAND UNDER SIMULATED IMPACT OF THE FOREARM AND HAND COMPLEX WITH FOUR DIFFERENT PADDING CONDITIONS OF WRIST GUARDS: a wrist guard without a volar splint (bare hand), with a volar splint (normal use), with a volar splint and additional viscoelastic polymeric padding, and a volar splint and additional air cell padding.In general, padding on the bare hand could improve the maximum energy absorption by more than 39%, while only the air cell padding could simultaneously attenuate the peak impact force by 32% without compromising the maximum energy absorption.Common wrist guard design requires more compliant padding in the volar aspect to improve the impact force attenuation, which should be done through optimal material selection and design.

Go S.-C.,Hanyang University | Kang D.-W.,Hanyang University | Im J.-B.,Hanyang University | Lee J.,Hanyang University | And 2 more authors.
Journal of Magnetics | Year: 2010

A 3-D.O.F. spherical PM motor has 3 degrees of freedom in its motion by tilting and rotating of a shaft, which can be applied in a range of fields. The back-EMF is proportional to the field flux and angular velocity. The back-EMF constant in conventional rotating machine has a uniform value. However, in a spherical PM motor, the back-EMF constant of the coils varies according to the tilting conditions regardless of whether the angular speed is constant. Consideration of the back-EMF constant is useful for designing 3-D.O.F. spherical PM motors. In this study, the back-EMF constant of the spherical PM motor was considered carefully. © 2010 Journal of Magnetics.

Ko Y.-B.,Korea Institute of Industrial Technology | Park H.-P.,Korea Institute of Industrial Technology | Kwon C.O.,Dong A Precision Co. | Cho S.-H.,DongYang Technical College
Annual Technical Conference - ANTEC, Conference Proceedings | Year: 2010

Forming of PET bottle was performed by injection- stretch blow molding. Blow molding is the process of blowing pressured air into heated preform to make contact with mold cavity. In this paper, the aim was to improve reliability of technical stabilization for the PET bottle that is last productive product and process technology which was able to do maximization by a preform performance enhancement of the uniform thickness that took temperature and a characteristic of materials. Preform design and molds manufacture were conducted using injection blow molding analysis results. Therefore thickness error of 5% for PET bottle can be obtained in this paper.

Park H.,Korea Institute of Industrial Technology | Cha B.,Korea Institute of Industrial Technology | Cho S.,Dongyang Technical College | Kim D.,Ajou University | And 3 more authors.
International Journal of Advanced Manufacturing Technology | Year: 2015

Insert parts in insert injection molding used to be deformed by pressure developed during the molding process. The plastic deformation of insert parts caused by injection pressure during insert injection molding for electric power plugs cannot be predicted by conventional injection molding analysis methods. In this study, the injection-structural coupled analysis was carried out to predict the plastic deformation of insert parts. Injection pressure developed during the molding process was calculated by the injection molding analysis software and was mapped onto the grid surface of the inner tube model for structural analysis as boundary conditions. The effect of process parameters such as injection time, melt temperature, and holding pressure on the injection pressure and the deformation of the inner tubes was examined to find the proper molding condition. The result from the analysis was compared to the insert injection molding experiment. Furthermore, the diameters of sub-runners in the multi-cavity mold of the power plugs were optimized to prevent the deformation of the inner tubes by the unbalanced filling of the melt into the linear arranged cavities using the injection-structural coupled analysis. © 2015 Springer-Verlag London

Song J.-D.,Dongyang Technical College
Telecommunications Policy | Year: 2010

In this paper, various equilibria are analyzed according to the leaderfollower relationship between vertically integrated incumbents when downstream entries are present. This analysis broadens our understanding of the incentives involved in deciding the wholesale price, which can be applied to explain the different situations of diffusion of mobile virtual network operators in the telecommunications market. Several implications are derived to facilitate effective policy formulation and management. © 2010 Elsevier Ltd. All rights reserved.

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