• Journal of Information Technology Services
• /
• v.14 no.4
• /
• pp.31-44
• /
• 2015

Local governments in Korea are involved in three types of online shopping sites : 'direct operation', 'outsourced operation', and 'sales agency.' They are different in terms of the site operator and the charging mechanism among a local government, the site operator, and local producers. This study analyzes their differences in site traffic, local producers' participation, promotion, and partnership. The results from the investigation of 72 shopping sites are the following. First, shopping sites of the 'direct operation' type and the 'outsourced operation' type show significantly higher participation of local producers. Second, the 'marketing agency' type has significantly higher number of promotional activities than the 'oursourced type' which has significantly higher number than the 'direct operation' type. Third, the number of partnerships in the 'marketing agency' type is the highest. The 'direct operation' type is the second and significantly higher than the 'outsourced type.' On the basis of the analysis results, this paper suggests an incubation ecosystem model as a better way of involvement by local governments in online shopping sites.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.5
• /
• pp.121-128
• /
• 2002

In this paper, the fuel economy of plug-in type hybrid electric vehicle is investigated through simulation. For the simulation study, 2 shaft type parallel hybrid powertrain is chosen and its operation modes are described. The operation algorithm which yields operation points of minimal fuel cost is suggested. Dynamic model fur operation of HEV and simulation procedure is described. Simulation results of fuel economy is compared to non plug-in type HEV as well as conventional vehicle. With total driving distance of 37km and full usage of 2kwh of electric energy stored in battery pack, plug-in type HEV shows 28-30% improved fuel economy compared to non plug-in type HEV and 86-93% improved fuel economy compared to conventional vehicle.

• Journal of Chest Surgery
• /
• v.23 no.5
• /
• pp.936-943
• /
• 1990

The Fontan operation for tricuspid atresia was first performed in 1968[Fontan and Baudet 1971] and several technical modifications of procedure were developed. We have experienced a case of modified Fontan operation for tricuspid atresia type Ic who was 5 years old female. She had previous palliative procedure \ulcornerpulmonary artery banding due to excessively increased pulmonary blood flow. The modified Fontan operation was right atrium to right ventricle connection with valve-bearing conduit. The result was good and the patient was discharged 20 days after operation.

• KEPCO Journal on Electric Power and Energy
• /
• v.2 no.3
• /
• pp.403-407
• /
• 2016

In general, drum-type boilers are designed for base load duty and applied under constant pressure operation mode. Recently, however conditions often occur that even drum-type boilers have to operate at partial load conditions. A feasibility study on adopting the sliding pressure operation for drum-type boiler was conducted, and corresponding performance changes and effects on the equipment were analyzed by utilizing a process simulation model. As a result, the conclusion was reached that drum type boilers are able to adopt the sliding pressure operation and can improve of net efficiency at part load operation in spite of the Rankine cycle efficiency reduction due to the decreases in main steam pressure. Because of thank to improvement of high pressure turbine stage-1 internal efficiency and power savings of boiler feed water pump. The sliding pressure operation is advantageous in terms of stress level relief for boiler tube as well as maintaining the rating steam temperature at part load condition. However, cautions are required because the drum boilers have poor dynamic response characteristics which may get worse during the sliding pressure operation.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.2
• /
• pp.586-594
• /
• 2015

This paper proposes a maximum efficiency operation strategy for three-level T-type inverter in entire operation areas. The three-level T-type inverter has higher and lower efficiency areas compared with two-level inverter. The proposed strategy aims to operate in the maximum efficiency point for the low-voltage and low-power home appliances. The three-level T-type inverter is analyzed in detail, and the two operation mode selection strategy is developed. The proposed algorithm is verified by theoretical analysis and experimental results.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.53 no.11
• /
• pp.619-623
• /
• 2004

We proposed the bridge type superconducting fault current limiter(SFCL) using switching operation of high-Tc superconducting(HTSC) thin film. The proposed bridge type SFCL consists of HTSC thin film, a diode bridge and a dc reactor. The controller for the operation of an interrupter is required in the conventional bridge type SFCL to prevent the continuous increase of fault current after a fault happens. On the other hand, the proposed bridge type SFCL can limit the fault current without the interrupter and the controller for its operation by the resistance generated when the gradually increased fault current exceeds HTSC thin film's critical current. We calculated the time when the gradually increased fault current started to be limited by the resistance generated in HTSC thin film after a fault happened and confirmed that it could be dependent on the amplitude of source voltage. The experimental results well agreed with the calculated ones from simulation.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.57 no.4
• /
• pp.388-394
• /
• 2008

The purpose of this paper is concerned with a battery type powered handpiece drive system for surgical operation. Battery type powered surgical handpiece is suitable for delicate surgical operating. The conventional air-type handpiece has a mechanical noise, a strong oscillation and a danger of infection. And the conventional contact switching type handpiece has problems that is restricted by surroundings. By reason of this kind, we studied noncontact switching type surgical handpiece to change conventional air type surgical handpiece and contact switching type. Also in this paper we develop the battery type power handpiece drive system for surgical operation using controller IC UC3625 of UNITRODE CO. Finally some experimental and simulation results are provided to demonstrate the validity of the proposed battery type power handpiece drive system.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.31A no.1
• /
• pp.84-92
• /
• 1994

In this paper, we present a novel scheduling algorithm using the weighted interval graph. An interval graph is constructed, where an interval is a time frame of each operation. And for each operation type, we look for the maximum clique of the interval graph: the number of nodes of the maximum clique represents the number of operation that are executed concurrently. In order to minimize resource cost. we select the operation type to reduce the number of nodes of a maximum clique. For the selected operation type, an operation selected by selection rule is moved to decrease the number of nodes of a maximum clique. A selected operation among unscheduled operations is moved repeatly and assigned to a control step consequently. The proposed algorithm is applied to the pipeline and the nonpipeline data path synthesis. The experiment for examples shows the efficiency of the proposed scheduling algorithm.

• Journal of Sensor Science and Technology
• /
• v.30 no.5
• /
• pp.295-299
• /
• 2021

In this study, we present a complementary metal-oxide-semiconductor (CMOS) binary image sensor. It can shoot an object rotating at a high-speed by using a gate/body-tied (GBT) p-channel metal-oxide-semiconductor field-effect transistor (PMOSFET)-type photodetector. The GBT PMOSFET-type photodetector amplifies the photocurrent generated by light. Therefore, it is more sensitive than a standard N+/P-substrate photodetector. A binary operation is installed in a GBT PMOSFET-type photodetector with high-sensitivity characteristics, and the high-speed operation is verified by the output image. The binary operations circuit comprise a comparator and memory of 1- bit. Thus, the binary CMOS image sensor does not require an additional analog-to-digital converter. The binary CMOS image sensor is manufactured using a standard CMOS process, and its high- speed operation is verified experimentally.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.59 no.4
• /
• pp.477-480
• /
• 2010

Fault current in power system is expected to increase by demand of power capacity. Therefore, when the fault occurred, fault current was increased in the power system. Many studies have been progressed to limit the fault current. Superconducting fault current limiter (SFCL) is one of them which has been studied in worldwide. In this paper, we will analyze characteristics of a transformer-type SFCL by reclosing operation when the voltage increases. Twice opening times in the reclosing of circuit breaker were set as the 0.5 and 15 seconds, respectively. Turn's number of primary and secondary coils set 4:2 and we increased voltages from 120V to 280V for each experiment. By the current waveform, maximum fault current in second and third cycles was lowered when the voltage was increased. In the recovery waveform, recovery time was increased as the voltage was increased. The reason was that power burden of the SFCL increased when consumption power was increased, so the time to get back to SFCL took longer. We compared the characteristics of a resistive-type and transformer-type SFCL. As a result, we found that the fault current of a transformer-type was lower than resistive-type and recovery time of the SFCL was shorter. Consequently, transformer-type SFCL was more profitable for limitation of fault current and recovery time under the same condition for reclosing operation.