• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.3
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• pp.317-329
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• 1998

In this paper, we have analyzed the packet error probability of DS/CDMA-Trellis Coded QPSK modulation signal with MRC(Maximum Ratio Combining) diversity reception in Rician fading, multi-user interferences and multipath channel. And then we have evaluated the performance and capacity of DS/CDMA-Trellis Coded QPSK system using the MRC diversity reception as a function of direct power to indirect power ratio ($K_R$), the number of diversity branch(M), the number of multi-user(U), PN chip rate(PN), the number of multipath channel($L_P$), and packet length(PL). From the results, we know that the coding gain of DS/CDMA-Trellis Coded QPSK system with 2 branch MRC diversity is about 6 dB against uncoded DS/CDMA BPSK system with 2 branch MRC diversity in Rician fading ($K_R=6dB), 5 multi-user interferences, and 3 multipath channel. And, we know that coded QPSK signal designed for the AWGN channel also perform well on a Rician fading channel with MRC diversity reception. Consequently, we expected that proposed system structure is reliable to the wireless data communication system in Rician fading, multi-user interferences, and multipath channel.

• Journal of Families and Better Life
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• v.35 no.2
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• pp.93-112
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• 2017

The adolescent birth rate has doubled in the recent decade. As a result, the Korean government has implemented support for adolescent single-parent families by expanding the scope of coverage of the Single-parent Family Support Act in 2010. In order to understand whether experiences of facility entry programs and the Single-parent Family Support Act for adolescent single-parents were helpful or not, this study verified the relationship to mental health. This study utilized a part of the National Youth Policy Institute's 'Research on the Actual Condition of the Adolescent Pregnancy, Birth and Rearing Children.' Participants of the study were 218 adolescent single-parents at the age of 24 and younger. This study used the research methods of descriptive statistical analysis, ${\chi}^2$test, t-test, and one-way analysis of variance. The findings and discussion of this study are as below: Firstly, the depression level of adolescent single-parents who had been raised by grandparents was higher than other family types to a meaningful standard and adolescent single-parent's cognition of the original family's economic level was related to self-esteem and parenting efficacy. Secondly, the practical single-parent family support policy for adolescent single-parent's pregnancy, birth and rearing children has shown a higher reception rate, and medical service of facility entry programs has a higher satisfaction level. However, some of the facility entry programs and the Single-parent Family Support Act have a low reception rate and it should be considered whether to maintain them or not.Lastly, parts of facility entry programs and the Single-parent Family Support Act for adolescent single-parents have increased self-esteem and parenting efficacy and reduced parenting stress and depression's levels.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.7
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• pp.629-634
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• 2016

This paper describes the implementation of a ZigBee sensor node that can be utilized as a multiband and machine to machine (M2M) communication gateway. The IEEE 802.15.4-2003 standard was used as the wireless network frequency band. Ember's Type EM357 SoC was used as the transmission and reception device to perform the communication function, and it was also used for both the main M2M gateway and the sensor node. For the implementation of the operating protocol, EmberZNet Stack 4.5.4 from the Ember Corporation was used. The measurement of the reception sensitivity in the receiving module and the actual output signal from the reference were obtained from the transmission of a packet, and the packet included the M2M gateway within the attached ZigBee sensor. The packet error rate was measured as 0% with a -98 dBm reception sensitivity at the ZigBee frequency. In addition, excellent current characteristics of the ZigBee modules were shown by the implementation of the low-power circuit.

• The Journal of the Korea Contents Association
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• v.15 no.12
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• pp.35-49
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• 2015

Recently, with the development of wireless communication technologies and mobile equipments, various studies on mobile P2P networks have been conducted. In this paper, we propose an advertisement dissemination method considering peer's mobilities and preferences in mobile P2P networks. The proposed scheme generates a peer's preference through the analysis of users' activities to disseminate advertisements with user preferences. To reduce duplicated advertising messages and improve reception ratio, the priority of advertisement re-dissemination is determined according to peer's preferences, mobilities, and advertisement reception ratio. We improve the participation rate of the advertisement dissemination of mobile peers using the incentive mechanism in mobile P2P networks. To show the superiority of the proposed scheme, we compare it with the existing scheme in terms of the number of messages and accuracy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.6
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• pp.446-453
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• 2013

Clustering schemes have been adopted as an efficient solution to prolong network lifetime and improve network scalability. In such clustering schemes cluster ratio is represented by the rate of the number of cluster heads and the number of total nodes, and affects the performance of clustering schemes. In this paper, we mathematically analyze an optimal clustering ratio in wireless sensor networks. We consider a multi-hop to one-hop transmission case and aim to provide the optimal cluster ratio to minimize the system hop-count and maximize packet reception ratio between nodes. We examine its performance through a set of simulations. The simulation results show that the proposed optimal cluster ratio effectively reduce transmission count and enhance energy efficiency in wireless sensor networks.

• Journal of Families and Better Life
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• v.29 no.4
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• pp.61-74
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• 2011

The purpose of this study was to target digital generation consumers and determine potential effects of their demographic characteristics and variables concerning digital consumer information upon their characteristics in purchasing clothing. This study has its implications in the sense that it determines digital generation's awareness and reception of digital consumer information and their utilization of digital consumer information source, so that it can help understand digital generation consumers' behaviors of information search and the phenomena of digital market in this age of knowledge and information, and can ultimately provide reference data useful for guidance in favorable consumer life as well as consumer education based on digital devices. The results of this study can be summed up as follows: It is found that digital generation consumers reached higher level in the awareness of digital consumer information. The reception of digital consumer information and the utilization of digital consumer information source are found as middle level. Based on these results, this study can give the following suggestions for consumer education: Lately, digital devices have been widely popularized into larger number of users, so that we have more chances to buy desired products on the web or mobile device. In particular, the rate of clothing purchase on the web tends to increase year by year. However, our digital consumers still lack in their ability to utilize digital consumer information in terms of quantitatively increasing purchase of products on the basis of digital consumer information. Thus, it is necessary to provide consumers with a formulated education in their information search and shopping using digital devices, so that they will have better ability to use digital consumer information in the future.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.3
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• pp.58-67
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• 2019

The low-voltage connection box used as a low-voltage transmission line of KEPCO is intended to branch or connect to an underground line. In comparison with the utility considering the aesthetics of the distance, and safety measures are needed. In this paper, temperature and humidity, $CO_2$, water level, acceleration, and vibration sensor are installed inside the underground low voltage handhole, and the sensor data is transmitted to the ground using the Zigbee module. Antenna (Bolted Antenna) for communication with the ground was proposed and the data reception through it was confirmed. In the LF mode and the HEX mode, the transmitted data was confirmed to be a perfect reception success rate. In the case of the bolted antenna, the difference between the ground state and the underwater state was observed as a result of the experiment in the environmental environment. However, It was judged that reception sensitivity was sufficient for communication. The received data could be confirmed through PC based GUI.

• ETRI Journal
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• v.30 no.1
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• pp.164-166
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• 2008

This paper proposes a priority-based duplicate burst transmission mechanism in an optical burst switching network to enhance the probability of successful reception of bursts. The performance of the proposed mechanism is evaluated by NS2 simulations. Our results show that the burst loss rate is improved especially under light traffic loads.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.639-641
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• 2002

In this paper, we proposed the multiple access control of RS232C Serial Communications protocol using collision sense method. The communications wires of data transmission and reception are tied together through the buffer each to connect to the multiple communication channels. The hardware interface and control program are designed to build the prototype system and the experimental multiple access communications network is built by multiple PC systems and the transfer completion rate results are shown.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.2
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• pp.1-8
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• 1994

In this paper, a model of trellis-coded M-ary PSK (TCM/M-PSK) for digital land mobile communication is realized. Bit error rate(BER) of TCM/M-PSK is calculated theoretically in time selective fading environment due to Doppler spread in the presence of AWGN. cochannel interference. These analyses are employed the receiver with post detection diversity and the direct sequence to improve the BER performance of TCM-MPSK system. It is shown that the CNR required by the diversity reception and the direct sequece(process gain=20dB) TCM-4PSK system is reduced to about 25 dB.