• Journal of the Ergonomics Society of Korea
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• v.36 no.1
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• pp.9-21
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• 2017

Objective: The objective of this study is to understand the effect of angle and curvature of push-return switches, which are external factors in the operation environment inside the cars, on the feel of operation and to propose optimum alternatives. Background: Customers' needs for products are changing from functional and performance aspects to customer-led type where customers can reflect on their needs on the products. The operation inside cars is executed by HMI. The push-return switch is utilized as the most intuitive mode of HMI; therefore, this push-return switch, which is widely used, has to be developed by assessing the preference and satisfaction of the customer. Method: The angle and curvatures, which are external factors that affect the feel of operation, are drawn through surveying the preceding research literatures. The stages to construct alternatives in experiments are as follows: (1) the tactile switch is replaced after dismantling the switch assembly to evaluate the internal characteristics proposed by preceding researches, (2) a drawing is prepared by using a design software, is printed using 3D printer, and then it is attached on the switch assembly, and (3) evaluation for satisfaction of operation is carried out by using a driving simulator. Results: Both the angle and curvature that are external factors of switch significantly affect the feel of operation. However, interaction between the two factors is found insignificant. Therefore, an optimum alternative is proposed considering the experimental outcomes. Conclusion: This study evaluates the satisfaction in operation that affects the feel of operation environment inside the cars. Based on the study results, a guideline for switch design in the center fascia is proposed. Application: This study is expected to be used as basic data for designing automotive switches, as well as switches in the industries similar with the operation environments of cars.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1511_1512
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• 2009

This paper presents a polarization switching antenna integrated with silicon RF MEMS SPDT switches in the form of a package. A low-loss quartz substrate made of SoQ (silicon-on-quartz) bonding is used as a dielectric material of the patch antenna, as well as a packaging lid substrate of RF MEMS switches. The packaging/antenna substrate is bonded with the bottom substrate including feeding lines and RF MEMS switches by BCB adhesive bonding, and RF energy is transmitted from signal lines to antenna by slot coupling. Through this approach, fabrication complexity and degradation of RF performances of the antenna due to the parasitic effects, which are all caused from the packaging methods, can be reduced. This structure is expected to be used as a platform for reconfigurable antennas with RF MEMS tunable components. A linear polarization switching antenna operating at 19 GHz is manufactured based on the proposed method, and the fabrication process is carefully described. The s-parameters of the fabricated antenna at each state are measured to evaluate the antenna performance.

• The Journal of the Korea Contents Association
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• v.5 no.3
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• pp.217-225
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• 2005

Currently the research on input-queued ATM switches is one of the most active research fields. Many achievements have been made in the research on scheduling algorithms for input-queued ATM switches and also applied in commerce. The scheduling algorithms have the characteristics of improving throughput, satisfying QoS requirements and providing service fairly. In this paper, we studied on an implementation of scheduler which arbitrates the input-queued ATM switches efficiently and swiftly. The proposed scheduler approximately provides $100\%$ throughput for scheduling. The proposed algorithm completes the arbitration for N-port VOQ switch with 4-iterative matching. Also the proposed algorithm has a merit for implementing the scheduling algorithm with 1/2 area compared to that of iSLIP scheduling algorithm which is widely used. The performance of the proposed scheduling algorithm is superior to that of iSLIP in 4-iterative matching.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.12
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• pp.624-630
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• 2001

The trend of the regulations on environmental issues are getting tight. Responding to this trend new technologies such as moving electrodes, wide pitch and pulsed power supply are also introduced in the electrostatic precipitator(EP) systems. The introduction of wide pitch and moving electrodes enhances the system performance of the EPs by improving air-flow and by improving the ash reentrainment on rapping. The power supplies for the EPs developed up to date include thyristor-based dc or intermittent type, SMPS(switching mode power supply) type and the pulsed-power supply type. The use of the pulsed ones is known to improve dust-collecting efficiency of high resistivity ash and reduces back corona occurrence in the collecting plate. There are two kinds of pulsed-power supplies; one with pulsed transformers and the other with direct dc switching devices. The latter uses rotary spark gap switches or semiconductor switches. Both have the merits and demerits: the spark gap switches are simple and robust but has short life time, hence, high maintenance cost, whereas the semiconductor switches have long life time but are costly. In this study, A high voltage power supply with superimposing voltage pulse on dc source was developed for EPs. This study describes circuit topology, operating principle of the scheme, and analysis of experimental results on Dong-Hae Power Plant. The pulsed power supply consists of a variable dc power supply with ratings of 60kV, 800mA and pulse generator which is made of high voltage thyristor-diode switch strings, an LC resonant tank and a blocking inductor. The pulse generator generates variable pulse-voltage up to 70kV using a high frequency resonant inverter with a variable dc source. Two prototypes were built and tested on 250MW DongHae power plant to verify the possibility of the commercial use and the normal operation in the transient states.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1B
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• pp.80-86
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• 2003

High speed networking applications like video-on-demand require the support of switches that can handle very high multicast loads. Switches studied in the past can support multicast loads of 25${\sim}$30% To overcome this limitation, Tandem Expanded Delta Network(TEDN) multicast switch was proposed to support more higher multicast load by 85${\sim}$90% without degradation in the performance But there is tremendous routing capacity that is not used in the series of routing network blocks. This paper presents modified TEDN multicast switches to save the excessive routing capacity. by recirculating packets in last routing network, we can achieve the acceptable packet loss ratio with the smaller number of routing network blocks. Extensive simulations show that our proposed switches have the acceptable packet loss ratio with reduced hardware cost.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.3
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• pp.283-292
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• 2011

This paper proposed a new multi-level inverter topology based on a H-bridge with two switches and two diodes connected to the DC-link. The output voltage of the proposed topology is quite closer to a sinusoidal waveform compared with a typical single phase inverter. The proposed multi-level inverter is applicable to a power conditioning system for renewable energy sources, and it can be also used as a building block of a cascaded multi-level inverter for a high voltage application. In case of conventional H-bridge type or NPC type multi-level inverter, 8 controllable switches are used to obtain a 5 level output voltage, but the proposed multi-level inverter requires only 6 controllable switches. Thus the circuit configuration is quite simple, reliable and cost-effective implementation is possible. The efficiency can be improved owing to the reduction of the switching loss. A new PWM method based on POD modulation is suggested which requires only one carrier signal. The switching sequence to make the capacitor voltage balanced is also considered. The feasibility is studied through simulation and experiment.

• Journal of KIISE:Information Networking
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• v.30 no.4
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• pp.520-534
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• 2003

In this paper, a performance evaluation model of the Fat-tree Network with the multiple-buffered crossbar switches is proposed and examined. Buffered switch technique is well known to solve the data collision problem of the switch network. The proposed evaluation model is developed by investigating the transfer patterns of data packets in a switch with output-buffers. Two important parameters of the network performance, throughput and delay, are then evaluated. The proposed model takes simple and primitive switch networks, i.e., no flow control and drop packet, to demonstrate analysis procedures clearly. It, however, can not only be applied to any other complicate modern switch networks that have intelligent flow control but also estimate the performance of any size networks with multiple-buffered switches. To validate the proposed analysis model, the simulation is carried out on the various sizes of Fat-tree networks that uses the multiple buffered crossbar switches. Less than 2% differences between analysis and simulation results are observed.

• Journal of Power Electronics
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• v.4 no.1
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• pp.39-45
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• 2004

A novel current-fed energy-recovery sustaining driver (CFERSD) for a PDP is proposed in this paper. Its main idea is to recover the energy stored in the PDP or to inject the input source energy to the PDP by using the current source built-up in the energy recovery inductor. This method provides zero-voltage-switching (ZVS) of all main power switches, the reduction of EMI, and more improved operational voltage margins with the aid of the discharge current compensation. In addition, since the current flowing through the energy recovery inductor can compensate the plasma discharge current flowing through the conducting power switches, the current stress through all main power switches can be considerably reduced. Furthermore, it features a low conduction loss and fast transient time. Operations, features and design considerations are presented and verified experimentally on a 1020${\times}$l06mm sized PDP, 50kHz-switching frequency, and sustaining voltage 140V based prototype.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.467-473
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• 2013

The addition of disconnect switches to a distribution feeder or the replacement of the manual switches with the automatic switches do, in general, increase reliability by decreasing the duration of the outage of many to the customers on the feeder and reducing the outage section. However, the improvement of reliability in power distribution system causes an increase of the investment cost, for example, replacement costs, labor costs, and so on. For this reason - the balance between investment and reliability improvement - many studies about the appropriate level of investment have been conducted. In this paper, we suggest the algorithm for determining the reasonable switch automation rate in the power distribution system. We evaluate the customer interruption cost and reliability for several cases - these cases relate with the switch automation rate - in the domestic metropolitan power distribution system, estimate the effectiveness of changing the manual switch to automatic switch quantitatively. These results can help the determining on the disconnect switch's automation rate.

• Journal of Power Electronics
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• v.15 no.3
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• pp.652-659
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• 2015

This paper presents a new hybrid soft switching dc-dc converter with a low circulating current and high circuit efficiency. The proposed hybrid converter includes two sub-converters sharing two power switches. One is a three-level PWM converter and the other is a LLC converter. The LLC converter and the three-level converter share the lagging-leg switches and extend the zero-voltage switching (ZVS) range of the lagging-leg switches from nearly zero to full load since the LLC converter can be operated at f_sw (switching frequency) $\approx$ f_r (series resonant frequency). A passive snubber is used on the secondary side of the three-level converter to decrease the circulating current on the primary side, especially at high input voltage and full load conditions. Thus, the conduction losses due to the circulating current are reduced. The output sides of the two converters are connected in series. Energy can be transferred from the input voltage to the output load within the whole switching period. Finally, the effectiveness of the proposed converter is verified by experiments with a 1.44kW prototype circuit.