• Journal of Korea Society of Digital Industry and Information Management
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• 제13권3호
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• pp.65-73
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• 2017

The fifth generation(5G) of wireless networks will connect not only smart phone but also unimaginable things. Therefore, 5G cellular network is facing the soaring traffic demand of numerous user devices. To solve this problem, a huge amount of 5G base stations will need to be installed. The base station positioning problem is an NP-hard problem that does not know how long it will take to solve the problem. Because, it can not find an answer other than to check the number of all cases. In this paper, to solve the NP hard problem, we compare the tabu search and the genetic algorithm using real maps for optimal cell planning. We also perform Monte Carlo simulations to study the performance of the Tabu search and Genetic algorithm for 5G cell planning. As a results, Tabu search required 2.95 times less computation time than Genetic algorithm and showed accuracy difference of 2dBm.

• Transactions of Materials Processing
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• 제18권7호
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• pp.531-537
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• 2009

The effect of blank holding force on thickness variation in simultaneous sheet forming with rectangular shape and circular has been demonstrated. Because has investigated an effect on formability of magnesium sheet, in this paper, the effect of punch radius on formability have been thinning, various crack phenomena and forming velocity. By simultaneously forming process with circular and rectangular shape, the data of simultaneously forming process with circular and rectangular shape will used to a part development such as notebook computer case, cell phone and bipolar plate of fuel cell.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.229-230
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• 2008

Recently, our lives have become more convenient and our work more efficient as a result of these cell phones. On the other hand, they have also caused diverse side-effects, including threats of blackmail with invasion of privacy, disclosure of personal information, as well as security breaches, and an overall increase in distrust between people. Recognizing the need to quickly collect digital evidence with an increase in cell phone crimes, this paper proposes to develop such standard module.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1082-1085
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• 2002

By improving Ec/Io of pilot channel in CDMA mobile communication, the transmitting quality of mobile phone may be improved, channel capacity may be increased, and further investment and operation cost may be reduced to build a network. In this paper suggested new cell pattern decision method for base station as one of ways to improve Ec/Io of pilot channel and verified its utility through simulation and field application data.

• Proceedings of the KIPE Conference
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.193-196
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• 2003

For a power source of usual electronic devices such as PDA, smart phone, UPS and electric vehicle, the battery made of serially connected multiple cells is generally used. In this case, if there are some unbalanced among cell voltages, the total lifetime and the total capacity of the battery are limited to a lower value. To maintain a balanced condition in cells, an effective method of regulating the cell voltage in indispensable. In this paper introduced a method for battery balancing system using dissipation in the resistance.

• Journal of KIISE:Computing Practices and Letters
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• 제14권1호
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• pp.63-70
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• 2008

As the number of cell phone users become growing, some researchers have presented that the imprudent use of mobile phones exerts harmful influence on electronic devices such as medical appliances, takeoff and landing system of aircraft. In this paper, we propose a usage model based on context-awareness which can be applied to mobile devices. The model controls the usage of both mobile devices themselves and mobile contents according to some context information like location, time, the circumference noise, etc. The proposed usage control model includes a dynamic role-based access control approach. To show the effectiveness of the proposed model, we have implemented a prototype system on an embedded board and PC server, and evaluated the performance of the system.

• Journal of the Institute of Electronics and Information Engineers
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• 제51권1호
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• pp.126-136
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• 2014

In the Advanced Driver Assistance Systems (ADAS) of smart vehicle and Intelligent Transportation System (ITS) for to detect the boundary of lane is being studied a lot of Hough Transform. This method detects correctly recognition the lane. But recognition rate can fall due to detecting straight lines outside of the lane. In order to solve this problems, this paper proposed an algorithm to recognize the lane boundaries and the accumulator cells in Hough space. Based on proposed algorithm, we develop application for Android was developed by H/W verification. Users of smart phone devices could use lane detection and lane departure warning systems for driver's safety whenever and wherever. Software verification using the OpenCV showed efficiency recognition correct rate of 93.8% and hardware real-time verification for an application development in the Android phone showed recognition correct rate of 70%.

• Journal of the Korea Convergence Society
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• 제9권4호
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• pp.271-283
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• 2018

This study aimed to investigate the effect of adolescent development environment including parenting attitude, peer relationship, and school environment on delinquent behavior, and between these relationships, the mediate effect of media environment such as computer and mobile devices. The $6^{th}$ year data from Korean Children & Youth Panel Survey (KCYPS) was used and the subjects were limited to 518 students of $7^{th}$ grade who are in their early adolescence. The result shows that adolescents under more affectionate, over involvement, and abusive parenting attitude will commit delinquent behaviors more frequently, and so does alienated youth from their friends. Parenting inconsistency and communication with friends make them use computer and cell phone more often, and excessive media usage increases adolescent's delinquent behavior. In conclusion, family environment and peer relation have influence on adolescents' delinquent behavior. Therefore, there is necessity to build development environment that prevent adolescents' delinquencies like parent education program or peer communication program for example. Also, proper education program for using computer or cell phone usage can reduce adolescents' delinquent behaviors, especially when its addictive aspect was recently issued.

• Wind and Structures
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• 제31권1호
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• pp.21-29
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• 2020

The wind field measurement of severe winds such as hurricanes (or typhoons), thunderstorm downbursts and other gales is important issue in wind engineering community, both for the construction and health monitoring of the wind-sensitive structures. Although several wireless data transmission systems have been available for the wind field measurement, most of them are not specially designed for the wind data measurement in structural wind engineering. Therefore, the field collection is still dominant in the field of structural wind engineering at present, especially for the measurement of the long-term and high-frequency wind speed data. In this study, for remote wind field measurement, a novel wireless long-term and high-frequency wind data acquisition system with the functions such as remote control and data compression is developed. The system structure and the collector are firstly presented. Subsequently, main functions of the collector are introduced. Also novel functions of the system and the comparison with existing systems are presented. Furthermore, the performance of this system is evaluated. In addition to as the wireless transmission for wind data and hardware integration for the collector, the developed system possesses a few novel features, such as the modification of wind data collection parameters by the remote control, the remarkable data compression before the data wireless transmission and monitoring the data collection by the cell phone application. It can be expected that this system would have wide applications in wind, meteorological and other communities.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제10권4호
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• pp.824-829
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• 2009

SMS service is widely used for providing the approval information of a credit card when the payment is made by a credit card. But the message contained in the SMS is very simple and includes one time approval information. Although detailed approval informations could be retrieved by means of wire-network or mobile network services, the wire-network service could not be used on moving and the mobile network service requires high cost. In this paper, a WIPI application program managing the approval informations of a credit card based on the accumulated SMS messages in the cell phone has been developed. A cell phone user can conveniently can get the useful information such as the approval list on last month, the approval list on this month, the total amount on this month and the information about payment by installment from the developed program without any cost.