• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.7
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• pp.1347-1353
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• 2015

We implemented a 10 Gb/s 4-channel vertical cavity surface emission lasers (VCSEL) driver array in a $0.13{\mu}m$ CMOS process technology. To enhance high current resolution, power dissipation, and chip space area, digital APC/AMC with time division sensing technology is primarily adopted. The measured -3 dB frequency bandwidth is 9.2 GHz; the small signal gain is 10.5 dB; the current resolution is 0.01 mA/step, suitable for the wavelength operation up to 10 Gb/s over a wide temperature range. The proposed APC and AMC demonstrate 5 to 20 mA of bias current control and 5 to 20 mA of modulation current control. The whole chip consumes 371 mW of low power under the maximum modulation and bias currents. The active chip size is $3.71{\times}1.3mm^2$.

• Journal of Auto-vehicle Safety Association
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• v.7 no.1
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• pp.7-12
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• 2015

NCAP(New Car Assessment Program) makes vehicle manufacturer improve safety performance through free competition and customers guarantee vehicle selection by providing information of vehicle safety. That's why it is important not only to meet the regulation, but also to cope with NCAP. EuroNCAP(European New Car Assessment Program) side tests have conducted by using Progressive MDB and Euro SID II in order to reproduce crash test between two vehicles over 10 years. However various researches report that Progressive MDB and Euro SID II do not reflect evolving vehicle design, impact performance and biofidelity of human. Therefore EuroNCAP has the plan to conduct AE-MDB side crash test using WorldSID which is more evolved from 2015 by replacing Progressive MDB and EuroSID II. Automobile manufacturers need to develop safety performance for new test closely. This paper is to find test set-up parameters which affect into dummy injury instead of restraint system and to research on its tendency. It is processed with mini and small car to know influence as changing vehicle size and also analyzed by DFSS(Design for six sigma) which is one of optimization tools. DFSS is vaildated by simulating CAE with L18 orthogonal array of 6 control factors adjustable as EuroNCAP requirement.

• Journal of Power Electronics
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• v.16 no.1
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• pp.362-373
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• 2016

The on-line measurement of high-power IGBT collector current is important for the hierarchical control and short-circuit and overcurrent protection of its driver and the sensorless control of the converter. The conventional on-line measurement methods for IGBT collector current are not suitable for engineering measurement due to their large-size, high-cost, low-efficiency sensors, current transformers or dividers, etc. Based on the gate driver, this paper has proposed a current measuring circuit for IGBT collector current. The circuit is used to conduct non-intervention on-line measurement of IGBT collector current by detecting the voltage drop of the IGBT power emitter and the auxiliary emitter terminals. A theoretical analysis verifies the feasibility of this circuit. The circuit adopts an operational amplifier for impedance isolation to prevent the measuring circuit from affecting the dynamic performance of the IGBT. Due to using the scheme for integration first and amplification afterwards, the difficult problem of achieving high accuracy in the transient-state and on-state measurement of the voltage between the terminals of IGBT power emitter and the auxiliary emitter (u_Ee) has been solved. This is impossible for a conventional detector. On this basis, the adoption of a two-stage operational amplifier can better meet the requirements of high bandwidth measurement under the conditions of a small signal with a large gain. Finally, various experiments have been carried out under the conditions of several typical loads (resistance-inductance load, resistance load and inductance load), different IGBT junction temperatures, soft short-circuits and hard short-circuits for the on-line measurement of IGBT collector current. This is aided by the capacitor voltage which is the integration result of the voltage uEe. The results show that the proposed method of measuring IGBT collector current is feasible and effective.

• International Journal of Computer Science & Network Security
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• v.21 no.6
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• pp.23-28
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• 2021

The article discusses the features of adaptation of the parameters of the physical layer of data transmission in self-organizing networks based on unmanned aerial vehicles operating in the conditions of "smart cities". The concept of cities of this type is defined, the historical path of formation, the current state and prospects for further development in the aspect of transition to "smart cities" of the third generation are shown. Cities of this type are aimed at providing more comfortable and safe living conditions for citizens and autonomous automated work of all components of the urban economy. The perspective of the development of urban mobile automated technical means of infocommunications is shown, one of the leading directions of which is the creation and active use of wireless self-organizing networks based on unmanned aerial vehicles. The advantages of using small-sized unmanned aerial vehicles for organizing networks of this type are considered, as well as the range of tasks to be solved in the conditions of modern "smart cities". It is shown that for the transition to self-organizing networks in the conditions of "smart cities" of the third generation, it is necessary to ensure the adaptation of various levels of OSI network models to dynamically changing operating conditions, which is especially important for the physical layer. To maintain an acceptable level of the value of the bit error probability when transmitting command and telemetry data, it is proposed to adaptively change the coding rate depending on the signal-to-noise ratio at the receiver input (or on the number of channel decoder errors), and when transmitting payload data, it is also proposed to adaptively change the coding rate together with the choice of modulation methods that differ in energy and spectral efficiency. As options for the practical implementation of these solutions, it is proposed to use an approach based on the principles of neuro-fuzzy control, for which examples of determining the boundaries of theoretically achievable efficiency are given.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3614-3619
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• 2022

To operate the ion cyclotron resonance heating (ICRH) antennas in a better heating state and produce relatively low impurities, it is necessary to control the antenna spectrum by changing the antenna phasing. As the electrical length of the antenna feeding transmission lines is changing as a matter of the standing wave pattern at the ceramic supports, 90° elbows, T-connectors and antenna loops, we chose to measure the current at the grounding points of the antenna loops by antenna strap probe. The voltage drops along a small, several millimeter-long paths at the end of the antenna loops give a signal that is proportional to the current in the antenna loop. Through the simulation of the antenna strap probe and the actual measurement of the antenna phasing under vacuum conditions, the reliability of the antenna strap probe based diagnostic system have been successfully proved. Moreover, this system was successfully applied to the ICRH daily experiments in the spring of 2021. In the near future, the active real-time feedback control of the antenna phasing system will be developed based on this diagnostic system in the EAST tokamak.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.239-241
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• 2011

Recently, studies on the indoor positioning system in application of wireless AP have been actively going on. The indoor wireless positioning system can be classified into several types according to the positioning techniques. Among them, the fingerprint technique is a technique that establishes the radio map by collecting MAC information of AP and RSSI (Received Signal Strength Indication) before executing positioning and then determines the position in comparison with the information of AP collected during the course of positioning. In the traditional fingerprint techniques, they control and manage by installing APs that are utilized for positioning. However, in case of specific indoors, the management can be done by installing a small number of APs but, in case of wide outdoors, it's practically impossible to install and manage equipments for positioning. In order to solve such problem, there is an improved fingerprint technique that utilizes the APs that are already scattered around. This technique will allow positioning without additional cost, but even the improved fingerprint positioning technique may incur dropped accuracy as well due to wide fluctuation of the AP information. In this paper, the traditional fingerprint technique and the improved fingerprint technique are explained in comparison, and we will compares difference in performance with the proposed WPS_WS (Wi-Fi Positioning System_Weak Signal) technique.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.3
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• pp.517-531
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• 1999

This paper presents the development of the 2-mode variable gain high power amplifier for a transmitter of INMARSAT-M operating at L-band(1626.5-1646.5 MHz). This SSPA(Solid State Power Amplifier) is amplified 42 dBm in high power mode and 36 dBm in low power mode for INMARSAT-M. The allowable error sets +1 dBm of an upper limit and -2 dBm of a lower limit, respectively. To simplify the fabrication process, the whole system is designed by two parts composed of a driving amplifier and a high power amplifier, The HP's MGA-64135 and Motorola's MRF-6401 are used for driving amplifier, and the ERICSSON's PTE-10114 and PTF-10021 are used the high power amplifier. The SSPA was fabricated by the circuits of RF, temperature compensation and 2-mode gain control circuit in aluminum housing. The gain control method was proposed by controlling the voltage for the 2-mode. In addition, It has been experimentally verified that the gain is controlled for single tone signal as well as two tone signals. The realized SSPA has 42 dB and 36 dB for small signal gain within 20 MHz bandwidth, and the VSWR of input and output port is less than 1.5:1 The minimum value of the 1 dB compression point gets 5 dBm for 2-mode variable gain high power amplifier. A typical two tone intermodulation point has 32.5 dBc maximum which is single carrier backed off 3 dB from 1 dB compression point. The maximum output power of 43 dBm was achieved at the 1636.5 MHz. These results reveal a high power of 20 Watt, which was the design target.the design target.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.4
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• pp.1711-1714
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• 2014

Objective: To explore the effect of Withaferin A on A549 cellular proliferation and apoptosis in non-small cell lung cancer (NSCLC). Materials and Methods: NSCLC cell line A549 was selected to explore the effect of Withaferin A on A549 cellular proliferation, apoptosis and the PI3K/Akt signal pathway capable of regulating tumor biological behavior by assessment of cellular proliferation, cellular apoptotic rates and cellular cycling as well as by immuno-blotting. Results: Withaferin A could inhibit A549 cellular proliferation and the control rate was dosage-dependent (P<0.05), which also increased time-dependently with the same dosage of Withaferin A (P<0.05). The apoptotic indexes in A549 cells treated with 0, 2.5, 5.0, 10.0 and 20.0 ${\mu}mol{\cdot}L^{-1}$ Withaferin A for 48 h were significantly different (P<0.05). In addition, the apoptotic rates of each group in both early and advanced stages were higher than those in 0 ${\mu}mol{\cdot}L^{-1}$ (P<0.05), which were evidently higher after 48 h than those after 24 h (P<0.05). A549 cells treated by Withaferin A for 48 h were markedly lower in Bcl-2 level and obviously higher in Bax and cleaved caspase-3 levels than those treated by 0 ${\mu}mol{\cdot}L^{-1}$ Withaferin A (P<0.05), and there were significant differences among 5, 10 and 20 ${\mu}mol{\cdot}L^{-1}$ Withaferin A (P<0.05). The ratios of A549 cells treated by Withaferin A for 48 h in G0/G1 stage were higher than those in 0 ${\mu}mol{\cdot}L^{-1}$, while those in S and G2/M stages were obviously lower than those in G2/M stage, and there were significant differences in 5.0, 10.0 and 20.0 ${\mu}mol{\cdot}L^{-1}$ Withaferin A (P<0.05). Additionally, p-Akt/Akt values were in reverse association with dosage, and the differences were significant (P<0.05). Conclusion: Withaferin A can inhibit the proliferation and apoptosis of A549 cells by suppressing activation of the PI3K/Akt pathways.

• Journal of Biosystems Engineering
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• v.31 no.2 s.115
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• pp.108-114
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• 2006

This study was conducted to design and fabricate a controller for variable-rate application of granular fertilizer based on physical and chemical information, to analyze the performance of the controller and characteristics of a discharger. The result of the study are summarized as follows: 1. The charge ratios of discharger by accumulation heights of fertilizer in hopper were examined, and the variations in charge ratio were $72.58{\sim}93.33%$ and $63.14{\sim}94.42%$ for the fertilizers Super 21 and Sinsedae, respectively. The charge ratio also decreased as the rotational speed of discharger increased. 2. The coefficient of variation of discharge amount by rotational speed and discharge time of discharger were in the range of $2.94{\sim}11.23%$ and $2.82{\sim}10.80%$ for the fertilizer of Super 21 and Sinsedae. Except the rotational speed of 12 rpm, the coefficient of variation for discharge amount were relatively small with 4% more or less 3. In order to evaluate the rotational speed of discharger, the control signal in the range of $0{\sim}5V$ was subdivided into the 50 steps by 0.1V. The regression equation for the rotational speed of discharger was Y=55.984X-79.174(X: input voltage, V, Y: discharger speed, RPM) and the $R^2$ was 0.99. 4. In order to evaluate the performance of the controller for variable-rate application of granular fertilizer, settling time to unit step input was examined. The settling time varied from 0.8sec to 1.4 sec.

• Journal of Biosystems Engineering
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• v.32 no.5
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• pp.339-347
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• 2007

A hexapod walking robot had been developed for gathering information in the field. The developed robot was $260{\times}260{\times}130$ ($W{\times}L{\times}H$, mm) in size and 14.7 N in weight. The legs had nineteen degrees of freedom. A leg has three rotational joints actuated by small servomotors. Two servomotors placed at ankle and knee played the roles of vertical joint for up and down motions of the leg and the other one placed at coxa played the role of horizontal joint for forward and backward motions. In addition, a servomotor placed at thorax between the front legs and the middle legs played the role of vertical joint for pumping the two front legs to climb stair or inclination. Walking motion of the robot was executed by tripod gait. The robot was controlled by manual remote-controller communicated by an infrared ray. Two controllers were equipped to control the walking of the robot. The sub-controller using PIC microcomputer (Microchips, PIC16F84A) received the 16 bit command signal from the manual remote controller, decoded it to 8bit and transmitted it to the main microcomputer (RENESAS, SH2/7045), which controlled the 19 servomotors using the PWM command signals. Walking speeds were controlled by adjusting the period of command cycle and the stride. Forward walking speed were within 100 cm/min to 300 cm/min. However, experimental walking speed had the error of 4-40 cm/min to compare with the theoretical one, because of slippage of the leg and the circular arc motion of servomotor of coxa.