• Journal of the Korea Society of Computer and Information
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• v.6 no.3
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• pp.78-83
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• 2001

In this paper, we are considered Nakagami-m fading, which can model variable multipath mobile radio communication channel, in DS-CDMA system. System modeling using nakagami -m fading is suited for urban mobile communication channel with multipath. We used adaptive serial search PN code acquisition scheme and derived the detection probability($P_D$) and false alarm probability($P_FA$) which have influence on code acquisition time, over Nakagami-m fading. Detection probability($P_D$) and false alarm probability($P_FA$) are detection variable to decide PN code acquisition time and should use to calculate mean and variance. of acquisition time. From computer simulation, we analyzed mean and variance about PN code acquisition of fading channel. Then we can apply it to the H/W design of mobile communication.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.6
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• pp.732-741
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• 2018

In order to maximize the usable capacity of a BMS (battery management system) that uses several battery cells connected in series, a cell balancing technique that equips each cell with the same voltage is needed. In the active cell balancing circuit using a multi-winding transformer, a balancing circuit that transfers energy directly to the cell (cell-to-cell) is composed of a PMOS switch and a gate driving chip for driving the NMOS switch. The TLP2748 photocoupler and the TLP2745 photocoupler are required, resulting in increased cost and reduced integration. In this paper, instead of driving PMOS and NMOS switching devices by using photocoupler, we proposed 70V BCD process based PMOS gate driving circuit, NMOS gate driving circuit, PMOS gate driving circuit and NMOS gate driving circuit with improved switching time. ${\Delta}t$ of the PMOS gate drive switch with improved switching time was 8.9 ns and ${\Delta}t$ of the NMOS gate drive switch was 9.9 ns.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.139-148
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• 2022

The research focuses on the interactional justice of organizational members and supervisors within Chinese organizations. In terms of organizational performance, the focus is on creativity by members, based on the need for innovation today. Furthermore, it verifies the influence of moral leadership on members' innovative behavior and the various effects of trust on members' superiors. This study empirically examined 330 Chinese small practitioners and identified the role of interactional justice in increasing the creative influence of organizational members to date in Chinese small. This study will propose ways to increase the level of creative and reduce the level of procedural justice, and discuss future research directions related to this.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.8
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• pp.753-760
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• 2009

In this paper, a novel planar spiral antenna of multi-tabs is proposed for wireless power transmission system based on low frequency magnetic inductive coupling. The proposed antenna has higher transmission efficiency than conventional antennas such a rectangular spiral antenna and a spiral antenna. Also, it has a useful property of uniform power transmission in the region of the antenna aperture. For verification, a transmitting antenna and a receiving one for a wireless power transmission system using magnetic inductive coupling of 132 kHz low frequency are designed and tested. The transmitting antenna has three-tabs spiral of unequal-space for higher uniform magnetic coupling in the antenna aperture. For reducing the receiving antenna size, two receiving antennas of unequal space two-tabs on one-side and series double sides as well are designed, respectively. From measurement, transmission efficiency of the proposed antennas is improved up to $3{\sim}10$ dB compared to conventional antennas.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.5
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• pp.17-32
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• 2023

The entrepreneurial activities of college students play a significant role in modern economic and social development, particularly as a solution to the changing economic landscape and youth unemployment issues. Introducing innovative ideas and technologies into the market through entrepreneurship can contribute to sustainable economic growth and social value. Additionally, the entrepreneurial intentions of college students are shaped by various factors, making it crucial to deeply understand and appropriately support these elements. To this end, this study systematically explores the importance and impact of role models through a multiple serial mediation analysis. Through a survey of 300 college students, the study analyzed how two psychological variables, growth mindset and entrepreneurial self-efficacy, mediate the influence of role models on entrepreneurial intentions. The presence and success stories of role models were found to enhance the growth mindset of college students, which in turn boosts their entrepreneurial self-efficacy and ultimately strengthens their entrepreneurial intentions. The analysis revealed that exposure to role models significantly influences the formation of a growth mindset among college students. This mindset fosters a positive attitude towards viewing challenges and failures in entrepreneurship as learning opportunities. Such a mindset further enhances entrepreneurial self-efficacy, thereby strengthening the intention to engage in entrepreneurial activities. This research offers insights by integrating various theories, such as mindset theory and social learning theory, to deeply understand the complex process of forming entrepreneurial intentions. Practically, this study provides important guidelines for the design and implementation of college entrepreneurship education. Utilizing role models can significantly enhance students' entrepreneurial intentions, and educational programs can strengthen students' growth mindset and entrepreneurial self-efficacy by sharing entrepreneurial experiences and knowledge through role models. In conclusion, this study provides a systematic and empirical analysis of the various factors and their complex interactions that impact the entrepreneurial intentions of college students. It confirms that psychological factors like growth mindset and entrepreneurial self-efficacy play a significant role in shaping entrepreneurial intentions, beyond mere information or technical education. This research emphasizes that these psychological factors should be comprehensively considered when developing and implementing policies and programs related to college entrepreneurship education.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.9C
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• pp.895-904
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• 2007

This paper proposes a robust sub-optimal smart antenna in Code Division Multiple Access (CDMA) basestation. It makes use of the property of the Least Mean Square (LMS) algorithm and the Conjugate Gradient Method (CGM) algorithm for beamforming processes. The weight update takes place at symbol level which follows the PN correlators of receiver module under the assumption that the post correlation desired signal power is far larger than the power of each of the interfering signals. The proposed algorithm is simple and has as low computational load as five times of the number of antenna elements(O(5N)) as a whole per each snapshot. The output Signal to Interference plus Noise Ratio (SINR) of the proposed smart antenna system when the weight vector reaches the steady state has been examined. It has been observed in computer simulations that proposed beamforming algorithm improves the SINR significantly compared to the single antenna case. The convergence property of the weight vector has also been investigated to show that the proposed hybrid algorithm performs better than CGM and LMS during the initial stage of the weight update iteration. The Bit Error Rate (BER) characteristics of the proposed array has also been shown as the processor input Signal to Noise Ratio (SNR) varies.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.4
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• pp.175-192
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• 2020

This study analyzed the effects of corporate dynamic capabilities on enterprise performance by using ambidextrous innovation activities as mediators, focusing on SME employees. The sub-variables of dynamic capabilities were divided into opportunity exploration capability, resource acquisition capability, and resource reconstruction capability. 282 questionnaires collected from small and medium-sized enterprises residing in the metropolitan area were used for empirical analysis. SPSS v22.0 and Process macro v3.4 were used to analyze the parallel multiple mediation model. First, the results of the analysis showed that opportunity exploration capability, resource acquisition capability had a positive (+) effect on the ambidextrous innovation activities, and the effect of resource reconstruction capability on ambidextrous innovation activities was not significant. Second, the ambidextrous innovation activities had a significant effect on the enterprise performance. Third, it was found that opportunity exploration capability and resource acquisition capability had a positive (+) effect on enterprise performance, and the effect of resource reconstruction capability on enterprise performance was not significant. Fourth, the ambidextrous innovation activity mediated the relationship between opportunity exploration capability and enterprise performance. Fifth, the ambidextrous innovation activity mediated the relationship between resource acquisition capability and enterprise performance. Sixth, the ambidextrous innovation activity did not mediate the resource reconstruction capability and the enterprise performance. As a follow-up study, it is necessary to find third mediators besides the mediators used in this study, analyze the serial mediation model through these, and study for the moderated mediation analysis through the conditional process model in which the moderator is introduced.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.263-268
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• 2000

In this paper, a new indirect feedback active noise control (ANC) scheme based on the fundamental frequency estimation is proposed for systems with a harmonic noise. When reference signals necessary for feedforward ANC configuration is difficult to obtain, the conventional ANC algorithms for multi-tonal noise do not measure the reference signals but generate them with the estimated frequencies. However, the beating phenomena, in which certain frequency components of the noise vanish intermittently, may make the adaptive frequency estimation difficult. The confusion in the estimated frequencies due to the beating phenomena makes the generated reference signals worthless. The proposed algorithm consists of two parts. The first part is a reference generator using the fundamental frequency estimation and the second one is the conventional feedforward control. We propose the fundamental frequency estimation algorithm using decision rules, which is insensitive to the beating phenomena. In addition, the proposed fundamental frequency estimation algorithm has good tracking capability and lower variance of frequency estimation error than that of the conventional cascade ANF method. We are also able to control all interested modes of the noise, even which cannot be estimated by the conventional frequency estimation method because of the poor SIN ratio. We verify the performance of the proposed ANC method through simulations for the measured cabin noise of a passenger ship and the measured time-varying engine booming noise of a passenger vehicle.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.3
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• pp.19-32
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• 2020

This study analyzed the effects of ICT technical characteristics of agricultural industry on smart farm entrepreneurial intention by using smart farm effort expectation and smart farm acceptance intention as mediators for smart farm pre-founders. Sub-variables of the technical characteristics of agricultural industry ICT were classified into availability, economics, data convergence and scalability. 349 questionnaires collected from pre-founders living in the country were used for empirical analysis. SPSS v22.0 and Process macro v3.4 were used to analyze the data based on serial multiple mediation model. First, economics and scalability had a positive (+) effect on start-up intention. Second, availability, economics and scalability had a significant effect on effort expectation. Third, effort expectation had a significant positive effect on acceptance intention. Fourth, acceptance intention had a significant positive effect on start-up intention. Fifth, the indirect effects of economics on start-up intention were all significant through effort expectation, through acceptance intention and through both effort expectation and acceptance intention. Sixth, the indirect effect of data convergence on start-up intention was significant through acceptance intention. Seventh, the indirect effect of scalability on start-up intention was significant through effort expectation and through both effort expectation and acceptance intention. As a follow-up study, it is necessary to study for the mediating variables other than mediators introduced in the study or the moderated mediation analysis through the conditional process model in which the moderating variable is introduced.

• Journal of KSNVE
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• v.10 no.6
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• pp.1059-1066
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• 2000

In this paper. a new indirect feedback active noise control (ANC) scheme barred on the fundamental frequency estimation is proposed for systems with a harmonic noise. When reference signals necessary for feedforward ANC configuration are difficult to obtain, the conventional ANC algorithms for multi-tonal noise do not measure the reference signals but generate them with the estimated frequencies.$^{(4)}$ However, the beating phenomena, in which certain frequency components of the noise vanish intermittently, may make the adaptive frequency estimation difficult. The confusion in the estimated frequencies due to the beating phenomena makes the generated reference signals worthless. The proposed algorithm consists of two parts. The first part is a reference generator using the fundamental frequency estimation and the second one is the conventional feedforward control. We propose the fundamental frequency estimation algorithm using decision rules. which is insensitive to the beating phenomena. In addition, the proposed fundamental frequency estimation algorithm has good tracking capability and lower variance of frequency estimation error than that of the conventional cascade ANF method.$^{(4)}$ We are also able to control all interested modes of the noise, even which cannot be estimated by the conventional frequency estimation method because of the poor S/N ratio. We verify the performance of the proposed ANC method through simulations for the measured cabin noise of a passenger ship and the measured time-varying engine booming noise of a passenger vehicle.