• The Journal of Industrial Distribution & Business
• /
• v.9 no.9
• /
• pp.25-33
• /
• 2018

Purpose - In this study, we consider and examine relationships between reasons for business switch or liquidation (BSL), and the demographics of small and medium enterprises (SMEs) in South Korea. The related five variables are occupations, administrative districts, age of employer, firm age and foundation motivation. In addition, eleven levels in association with reasons for BSL visualize the corresponding demographics by measuring their similarity on the dimensional planes assuming that the association exists between variables under consideration. Research design, data, and methodology - This study is done by the Ministry of SMEs and Startups in 2016 and examines 20,307 small and medium enterprises. For examining the distinct relationships among variables under consideration, both chi-squared test and correspondence analysis as main statistical tools are used. Results - The results show that among levels of reasons for BSL the three levels -weakening profitability, poor sales and economic depression- are main ones for the five demographics variables mentioned above, and we can obtain the detailed associations between attributes of corresponding variables by inspecting the two dimensional plane. Conclusions - This study suggests reasons for BSL are closely associated with the five different demographics variables - Administrative districts, Firm age, Occupations, Age of employer and Foundation motivation-by looking over results.

• Proceedings of the KIPE Conference
• /
• 2004.07b
• /
• pp.723-727
• /
• 2004

A new high-performance and low cost single switch energy recovery display driver for an AC plasma display panel (PDP) is proposed. Since it is composed of only one auxiliary power switch, two small inductors, and eight diodes compared with the conventional circuit consisting of four auxiliary power switches, two small inductors, eight power diodes, and two external capacitors, it features a much simpler structure and lower cost. Nevertheless, since the rootmean-square (RMS) value of the inductor current is very small, it also has very desirable advantages such as n low conduction loss and high efficiency. Furthermore, there are no serious voltage-drops caused by the large gas-discharge current with the aid of the discharge current compensation, which can also greatly reduce the current flowing through power switches and maintain the panel to light at n lower sustaining voltage. In addition, all main power switches are turned on under the zero-voltage switching (ZVS) and thus, the proposed circuit has a improved EMI, increased reliability, and high efficiency. Therefore, the proposed circuit will be well suited to the wall hanging PDP TV. To confirm the validity of the proposed circuit, circuit operations, features,and design considerations are presented and verified experimentally on a 6-inch PDP, 50kHz-switching frequency, and sustaining voltage 141V based prototype.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.41 no.7
• /
• pp.71-79
• /
• 2004

Packet-type data transmission is characterized by the continuous transmission of massive data with relatively constant rate. In such transmission, the dynamic power consumed on buses is influenced by the sequence of transmitted data. A new coding scheme called Sequence-Switch Coding (SSC) is proposed in this paper. SSC reduces the number of bus transitions in the transmission of packet-type data by changing the sending order of the data. Some simple algorithms are presented, In. The simulation results show that SSC outperforms the well-known Bus-Invert Coding with these algorithms. SSC is not a specific algerian but a method to reduce the number of bus-transitions. There could be lots of algorithms for realizing SSC. The variety of SSC algorithms provides circuit designers a wide range of trade-off between performance and circuit complexity.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.3 no.4
• /
• pp.167-174
• /
• 2003

This paper proposes a network processor especially optimized for content switching. With 2Gbps port capability, it integrates packet processor cluster, content-based classification engine and traffic manager on a single chip. A switch fabric architecture is also designed for scale-up of the network processor's capability over hundreds gigabit bandwidth. Applied in real network systems, the network processor shows wire-speed network address translator (NAT) and content-based switching performance.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.3
• /
• pp.1015-1024
• /
• 2015

This paper introduces a low cost, high efficiency, high performance three-phase unified power quality conditioner (UPQC) by using four-switch three-phase inverters (FSTPIs) and an extra capacitor in the shunt active power filter (APF) side of the UPQC. In the proposed UPQC, both shunt and series APFs are developed by using FSTPIs so that the number of switching devices is reduced from twelve to eight devices. In addition, by inserting an additional capacitor in series with the shunt APF, the DC-link voltage in the proposed UPQC can also be greatly reduced. As a result, the system cost and power loss of the proposed UPQC is significantly minimized thanks to the use of a smaller number of power switches with a lower rating voltage without degrading the compensation performance of the UPQC. Design of passive components for the proposed UPQC to achieve a good performance is presented in detail. In addition, comparisons on power loss, overall system efficiency, compensation performance between the proposed UPQC and the traditional one are also determined in this paper. Simulation and experimental studies are performed to verify the validity of the proposed topology.

• Progress in Superconductivity and Cryogenics
• /
• v.14 no.3
• /
• pp.53-59
• /
• 2012

Adiabatic demagnetization refrigerator (ADR) for hydrogen re-liquefaction operating between 24 K and 20 K has been designed. $Dy_{0.9}Gd_{0.1}Ni_2$, whose Curie temperature is 24 K, is selected as a magnetic refrigerant. The magnetic refrigerant powder is sintered with oxygen-free high purity copper (OFHC) powder to enhance its effective thermal conductivity as well as to achieve relatively high frequency. A perforated plate heat exchanger (PPHE) operated with forced convection is utilized as a heat switch. The forced convection heat switch is expected to have fast response relative to a conventional gas-gap heat switch. A conduction-cooled high Tc superconducting (HTS) magnet is employed to apply external magnetic field variation on a magnetic refrigerant. $2^{nd}$ generation GdBCO coated conductor HTS tape with Kapton$^{(R)}$ insulation (SUNAM Inc.) will be utilized for the HTS magnet. The magnetization and demagnetization processes are to be achieved by the AC operation of the HTS magnet. The designed magnetic field and target ramp rate of the HTS magnet are over 4 T with 180 A and 0.4 T/s, respectively. AC loss distribution on HTS magnet is theoretically estimated.

• ETRI Journal
• /
• v.36 no.6
• /
• pp.881-888
• /
• 2014

This paper studies the magnetic coupling between two adjacent loop antennas that are parallel to each other in a plane and presents a new practical method to avoid the resulting magnetic coupling interference. The study focuses on the high frequency radio-frequency identification (RFID) system for casino applications, where several loop antennas are closely built into a game table to monitor gaming chips. In this case, neighboring loop antennas may severely interfere with each other by magnetic coupling, which leads to the malfunction of the RFID system. In this paper, we present a practical loop antenna with a new loop switch circuit for avoiding magnetic coupling. The loop switch circuit is integrated with a matching circuit and automatically operated by using an interrogating signal from a reader. We verified the validity of the proposed design by showing that an RFID reader with the proposed antenna can exactly and separately read the gaming chips placed on the different betting zones of a game table.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.15 no.4
• /
• pp.341-352
• /
• 1990

In this paper, we introduce tree types of switching networks, I, e., a fully segregated type, a partially integrated type, and a fully integrated type switch, to accommodate nx 64Kb/s multi-slot connection traffic and analyze their blocking probabilites for the different traffic mixes by utilizing a computational algorithm of blocking probability, and finally determine the traffic handling capacity which satisfies the given grade of service. The fully integrated type switch can accommodate the ISDN traffic with relatively low wideband traffic. However, either the partially integrated type or the fully segregated type switch is needed to accommodate the ISDN traffic as the wideband traffic increases. This result can be usilized in the design of ISDN switching networks accommodating multi-slot connection traffic.

• Journal of Power Electronics
• /
• v.6 no.2
• /
• pp.131-138
• /
• 2006

An active clamp ZVS PWM forward converter using a secondary synchronous switch control is proposed in this paper. The proposed converter is suitable for low-voltage and high-current applications. The structure of the proposed converter is the same as a conventional active clamp forward converter. However, since it controls the secondary synchronous switch to build up the primary current during a very short period of time, the ZVS operation is easily achieved without any additional conduction losses of magnetizing current in the transformer and clamp circuit. Furthermore, there are no additional circuits required for the ZVS operation of power switches. Therefore, the proposed converter can achieve high efficiency with low EMI noise, resulting from soft switching without any additional conduction losses, and shows high power dens~ty, a result of high efficiency, and requires no additional components. The operational principle and design example are presented. Experimental results demonstrate that the proposed converter can achieve an excellent ZVS performance throughout all load conditions and demonstrates significant improvement in efficiency for the 100W (5V, 20A) prototype converter.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.5
• /
• pp.1076-1081
• /
• 2007

In this paper, we propose a new switch structure for time division duplex(TDD) system. The existing TDD structure utilizes a circulator fur isolation characteristic between ports. However, the circulator produces intermodulation distortion signals which are undesired signal because of its nonlinear properties. The proposed circuit is composed of a modified branch-line hybrid coupler which controls the signal flow while the isolated port is open-/short- terminated. In order to prove the validity of the presented structure, the switch circuit is fabricated and measured at 2.3GHz, the center frequency of Wibro service system.