• Journal of Industrial Convergence
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• v.20 no.12
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• pp.11-25
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• 2022

In this study, we want to verify the factors that affect the intention to switch to a supply chain management information system applied with blockchain. To this end, variable selection and research model were constructed through the review of previous studies, and empirical analysis was conducted using the TOE framework and PPM model. The effects of Push and Pull factors on the intention to switch to the block chain system and the moderating effect through the switching cost which is a Mooring factor, were verified. The hypothesis was verified using a structural equation model using a sample of 320 response data by conducting a questionnaire survey on small and medium-sized enterprises located in Korea. As a result of the study, social influence, which is a push factor, and management's will to innovate, which is a Pull factor, had a significant effect on switching intention. And the moderating effect between the groups with high and low switching cost recognition was confirmed. This study is significant in that it presents the concept and research direction of SCBM (supply chain & blockchain management) that can enhance the competitiveness of a company through the implementation of a blockchain-based supply chain management information system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3114-3120
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• 2014

Wireless emergency call switch used in industry, the most important thing is the sustainable power supply. This paper describes the development and performance test results of a compact electromagnetic energy harvesting mechanism for batteryless wireless switch. This paper summarizes proposed structure design and magnetic field analysis results of the mechanism to generate an induced electromotive force using 2mm stroke of a single push action. This analysis results show the power output of the proposed mechanism up to VDC $4.5V{\pm}25%$ and it can hold up to 65ms of the power generation with greater than 2.5V.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.4
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• pp.65-72
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• 2000

This paper proposes a Push type High Frequency DC-DC Converter using Zero Voltage Switching to reduce turn on and off loss at the switching instants. This paper has a advantage which is able to operating safely in load short, because DC reactor is connected with resonance reactor in order to supply a fixed safely in load short, because DC reactor is connected with resonance reactor in order to supply a fixed current with low ripple from DC power supply. The capacitor $(C_1, C_2)$ connected in switch are a common using as resonance capacitor and ZVS capacitor. The analysis of the proposed high frequency resonance DC-DC converter is generally described by using normallized parameter, and we has evaluated characteristic values which is needed to design a circuit. We conform a rightfulness of theoritical analysis by comparing a theoretical values and experimental values obtained from experiment using MOSFET as switching devices.

• Journal of Power Electronics
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• v.14 no.3
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• pp.444-457
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• 2014

This paper presents the design and realization of a digital PV simulator with a Push-Pull Forward (PPF) circuit based on the principle of modular hardware and configurable software. A PPF circuit is chosen as the main circuit to restrain the magnetic biasing of the core for a DC-DC converter and to reduce the spike of the turn-off voltage across every switch. Control and I/O interface based on a personal computer (PC) and multifunction data acquisition card, can conveniently achieve the data acquisition and configuration of the control algorithm and interface due to the abundant software resources of computers. In addition, the control program developed in Matlab/Simulink can conveniently construct and adjust both the models and parameters. It can also run in real-time under the external mode of Simulink by loading the modules of the Real-Time Windows Target. The mathematic models of the Push-Pull Forward circuit and the digital PV simulator are established in this paper by the state-space averaging method. The pole-zero cancellation technique is employed and then its controller parameters are systematically designed based on the performance analysis of the root loci of the closed current loop with $k_i$ and $R_L$ as variables. A fuzzy PI controller based on the Takagi-Sugeno fuzzy model is applied to regulate the controller parameters self-adaptively according to the change of $R_L$ and the operating point of the PV simulator to match the controller parameters with $R_L$. The stationary and dynamic performances of the PV simulator are tested by experiments, and the experimental results show that the PV simulator has the merits of a wide effective working range, high steady-state accuracy and good dynamic performances.

• Information Systems Review
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• v.16 no.3
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• pp.135-160
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• 2014

Most Social Network Service (SNS) provide online chat, video and file sharing, blogging and others. Because of this advantage, people depend on SNS to communicate with others. However, recently SNS encourage people to reveal too much information broadly so SNS users are concerned about privacy invasion and data spill. They also feel fatigue in process of touching people they don't know while using SNSs. That is the reason why they attempt to switch from opened SNS to Closed SNS. Therefore, the purpose of this study is to empirically investigate and analyze the effect of the factors on the SNS users' switching behavior when using SNS. To accomplish this purpose, this research adopted "Push-Pull-Mooring (PPM)" framework. The PPM is proposed by population geologist, who used it to explain the incentives of demographic migration. Following PPM model, this research empirically examines the three categories of antecedents for SNS switching intention toward closed SNS: push (i.e., weak connection, privacy concern, relative complexity), pull (i.e., enjoyment, belongingness, peer influence), mooring (i.e., SNS fatigue, user resistance) factors. The survey was conducted for 285 users on SNS communities in Korea. The results of this study are as follows; First, wear connection and privacy concern are significantly related to SNS switching intention. Second, enjoyment and belongingness are significantly related to SNS switching intention. Finally, the results show that SNS fatigue has a moderating effect on the links between push factors and SNS switching Intention. Also, user resistance has a moderating effect on the links between pull factors and SNS switching Intention. These findings contribute to the SNS literature both theoretically and practically.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.218-226
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• 2017

In this paper, optical transport network in real time monitoring system using smart phone. The existing housing using monitoring was a smart phone of optical transport network access switch about an event with new installation of cognitive system in real time. This paper can this problem to be solved of the invention in real time maintenance using smart phone application and optical cable closure switch. If you want to find optical cable closure fault location, this smart phone web is very useful. Cable tie is isolation of fiber spare board from fiber switch tie occur push message. Housing and access, and an external failures otdr the measurement of the global positioning to be able to easily using the This paper can find event of optical cable closure unauthorized work and fault using smart phone OTDR function. the optical cable fault time reduction and network transport quality by managing real time optical cable section by using the smart phone can be maintained efficiently.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.708-712
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• 2001

A new phase-shifted parallel-input/series-output (PI SO) dual inductor-fed push-pull converter for high-power step­up applications is proposed. This converter is operated at a constant duty cycle and employs an auxiliary circuit to control the output voltage with a phase-shift between the two modules. It features a voltage conversion characteristic which is linear to changes in the control input, and high step-up ratio with a greatly reduced switch turn-off stress resulting in a significant increase in the converter efficiency. It also shows a low ripple content and low root-mean-square (RMS) current in the output capacitor. The operational principle is analyzed and a comparative analysis with the conventional pulse-width-modulated (PWM) PISO dual inductor-fed push-pull converter is presented. A 50kHz, 800W, 350Vdc prototype with an input of 20-32Vdc has also been constructed to validate the proposed converter. The proposed converter compares favorably with the conventional counterpart and is considered well suited to high-power step-up applications.

• Journal of Power Electronics
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• v.1 no.2
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• pp.78-87
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• 2001

A new high-power step-up based on the two-module parallel-input (PISO) modular dual inductor-fed push-pull converter is proposed. The proposed converter is operated at a constant duty cycle and employs and auxiliary circuit to control the output voltage with a phase-shift between two modules. It shows a high efficiency due to the greatly reduced switch turn-off stress. It also shows a high and linear voltage conversion ratio, low current stress in the output capacitor, and fast control-to-output dynamics. The operation principles and the mathematical models of the proposed converter are presented. Features of the proposed converter are discussed in comparison with the two-module PISO modular dual inductor-fed push-pull converter. Also, experimental results from a 50kHz, 800W, 350 Vdc prototype with an input voltage range of 20-32 Vdc are provided to confirm the validity of the proposed converter. The new converter compares favorably with the conventional counterpart, and is considered well siuted to high-power step-up applications.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.5
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• pp.384-390
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• 2022

In this study, a single-stage, four-phase, interleaved, totem-pole AC-DC converter is proposed for a super-fast charger station that requires high power, a wide voltage range, and bidirectional operation capabilities and adopts various types of electric transport vehicles. The proposed topology is based on current-fed push-pull dual active bridge converter combined with the totem-pole operation. Owing to the four-phase interleaving effect, the bridge on the grid side can switch at 0.25, 0.5, and 0.75 to achieve a ripple-free grid current. The input filter can be removed theoretically. Switching methods for the duty of the secondary-side duty cycle are proposed, and they correspond to the primary duty cycle for reducing the circulating power and handling the total harmonic distortion. Therefore, the converter can operate under a wide voltage range. Experimental results from a 7.5 kW prototype are used to validate the proposed concept.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.3
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• pp.149-155
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• 2006

This paper presents a torsional micromirror detached from PZT actuators (TMD), whose rotational motion is achieved by push bars in the PZT actuators detached from the micromirror. The push bar mechanism is intended to reduce the bending, tensile and torsional constraints generated by the conventional bending bar mechanism, where the torsional micromirror is attached to the PZT actuators (TMA). We have designed, fabricated and tested prototypes of TMDs for single-axis and dual-axis rotation, respectively. The single-axis TMD generates the static rotational angle of $6.1^{\circ}$ at 16 VDC, which is 6 times larger than that of single-axis TMA, $0.9^{\circ}$. However, the rotational response curve of TMD shows hysteresis due to the static friction between the cover and the push bar in the PZT actuator. We have shown that 63.2% of the hysteresis is due to the static friction caused by the initial contact force of the PZT actuaor. Without the initial contact force, the rotational response curve of TMD shows linear voltage-angle characteristics. The dual-axis TMD generates the static rotational angles of $5.5^{\circ}$ and $4.7^{\circ}$ in x-axis and y-axis, respectively at 16 VDC. The measured resonant frequencies of dual-axis TMD are $2.1\pm0.1$ kHz in x-axis and $1.7\pm0.1$ kHz in y-axis. The dual-axis TMD shows stable operation without severe wear for 21.6 million cycles driven by 16 Vp-p sinusoidal wave signal at room temperature.