• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.31 no.6 s.261
• /
• pp.718-724
• /
• 2007

Some of gas turbine model of 7F-Class has constructed and is operating with units domestically. Non-destructive testing (NDT) is one of the methods being used to inspect damage $1^{st}$ stage bucket and review damage trends. We also analyze damage configuration and microstructure according to material and compare with pape of electric power research institute (EPRI). The damaged mode could be determined by leveraging failure analysis. Especially, configuration uprate of bucket is not only to prevent damage during operation but also avoid domestic manufacturing by the competitors. Modifications were mainly concentrated on surfaces such as cooling hole and bucket tips. Analyzing of bucket damage, the earlier model of 7F-Class used with one cycle with equivalent operation hour (EOH), has various cracking of the bucket surface. Bucket damage of new model is centered on tip area (54%) as analyzed by EPRI research. We conclude that improving bucket configuration would increase repair rate on the bucket tip.

• ETRI Journal
• /
• v.26 no.1
• /
• pp.7-13
• /
• 2004

To improve the characteristics of breakdown voltage and specific on-resistance, we propose a new structure for a LDMOSFET for a PDP scan driver IC based on silicon-on-insulator with a trench under the gate in the drift region. The trench reduces the electric field at the silicon surface under the gate edge in the drift region when the concentration of the drift region is high, and thereby increases the breakdown voltage and reduces the specific on-resistance. The breakdown voltage and the specific on-resistance of the fabricated device is 352 V and $18.8 m{\Omega}{\cdot}cm^2$ with a threshold voltage of 1.0 V. The breakdown voltage of the device in the on-state is over 200 V and the saturation current at $V_{gs}=5V$ and $V_{ds}$=20V is 16 mA with a gate width of $150{\mu}m$.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.42 no.12
• /
• pp.141-148
• /
• 2005

This paper addresses the design of srTCM (single rate Three Color Marker) described in RFC2697. It has proposed for srTCM to be used at the ingress of Differentiated Service network that provides AF PHB (Assured Forwarding Per Hop Behavior). srTCM is the marker with the metering function, and consists of the token updating function and the marking function. The token updating function uses the dual token bucket. The marking function compares the token values with the length of input packet, and then marks the result into IP QoS field (ToS field). This paper designs srTCM function and then implements it in one chip using VHDL and FPGA technology.

• Journal of Families and Better Life
• /
• v.17 no.3
• /
• pp.1-16
• /
• 1999

This study focuses on the beginning of transition to parenthood expectation and applies the exchange theory in order to examine reward and cost of transition to parenthood expectation and picks up the main cause effecting it. This study conducted structured questionnaires to total 330 first pregnant women and examined descriptive statistics and t-test F-test analysis by using collected data. And here are the result of research. First the transition to parenthood expectation expected rewards much more than costs and had much importance on individual aspects in parenthood. The more were they aged hardly educated and housewives the higher did they showed expectation of reward. The less did they have high education the more did they expect costs of the transition to parenthood expectation. Second to examined the reward/cost of transition to parenthood expectation according to martial satisfaction the more did they have martial satisfaction the more did they expectation of the rewa ds on transition to parenthood expectation. On the contrary the more did they respect from husbands the less did they cost of transition to parenthood expectation. This study would be helpful to lead family life having childbirth to the positive way be examining the process from childbirth plan to delivery. Also it will be applicable to seek for the methods to help would-be parents as basic data on material on education about transition to parenthood.

• Journal of Communications and Networks
• /
• v.6 no.1
• /
• pp.26-34
• /
• 2004

A blind interference canceller in the presence of subchipspaced multipath channels for direct-sequence code division multiple access (DS-CDMA) down-link system is considered. This technique is based on combining the existing blind interference canceller with a technique that involves assigning subchip-tap spacing to the Rake receiver. The proposed receiver minimizes the receiver’s output energy subject to a constraint in order to mitigate the multiple access interference (MAI) along each multipath component, and then suboptimally combining all the multipath components. Moreover, it is able to mitigate the mismatch problem when subchip-spaced multipath components arrive at the blind interference canceller. It is known that optimal combining techniques perform a decorrelation operation before combining, which requires both knowledge and computational complexity. In the following, we have adopted a simpler but suboptimum approach in the combining of the suppressed signals at the output of our proposed receiver. Computer simulation results verify the effectiveness of the proposed receiver to handle subchip-spaced multipath components and still suppresses MAI significantly.

• Journal of Communications and Networks
• /
• v.15 no.2
• /
• pp.173-178
• /
• 2013

It is a concern that eco-driving vehicles, because their driving behavior differs from other vehicles due to e.g. e-start, may inhibit smooth traffic flow. Therefore, it is necessary to study the cooperative eco-driving done by a vehicle group, putting "vehicle-to-vehicle communication" and "road-to-vehicle communication" into perspective. Based on these factors, this study aimed to: 1) Analyze fuel consumption rates and driving behaviors of more than one vehicle following an Eco-Driving vehicle. 2) Examine the effect of information on the fuel consumption rate of the preceding vehicles on the following vehicles. As a result, the following findings were obtained: 1) By providing information to multiple following vehicles, the fuel consumption rate of the second vehicle was not lowered, while that of the third one was. 2) It is possible that, when information on fuel consumption of a preceding vehicle is provided to the following one, an inter-vehicular distance is shortened during deceleration to contribute to smooth traffic flow. From the above results, it is suggested that, when targeting a vehicle group, sharing the information on preceding vehicles is effective.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.49 no.8
• /
• pp.557-564
• /
• 2000

A very simple control approach using neural network for the robust position control of a Permanent Magnet Synchronous Motor(PMSM) is presented. The linear quadratic controller plus feedforward neural network is employed to obtain the robust PMSM system approximately linearized using field-orientation method for an AC servo. The neural network is trained in on-line phases and this neural network is composed by a feedforward recall and error back-propagation training. Since the total number of nodes are only eight, this system can be easily realized by the general microprocessor. During the normal operation, the input-output response is sampled and the weighting value is trained multi-times by error back-propagation method at each sample period to accommodate the possible variations in the parameters or load torque. In addition, the robustness is also obtained without affecting overall system response. This method is realized by a floating-point Digital Signal Processor DS1102 Board (TMS320C31).

• Transactions on Electrical and Electronic Materials
• /
• v.1 no.2
• /
• pp.7-11
• /
• 2000

a-Si:H and poly-Si TFT(thin film transistor) characteristics were investigated using an inverted staggered type TFT. The TFT an as-grown a-Si:H exhibited a low field effect mobility, transconductance, and high gate threshold voltage. The poly-Si films were achieved by using an isothermal and RTA treatment for glow discharge deposited a-Si:H films. The a-Si:H films were cystallized at the various temperature from 600$^{\circ}C$ to 1000$^{\circ}C$. As anneal temperature was elevated, the TFT exhibited increased g$\sub$m/ and reduced V$\sub$ds/. V$\sub$T/. The poly-Si grain boundary passivation with grain boundary trap types and activation energies as a function of anneal temperature. The poly-si TFT showed an improved I$\sub$nm//I$\sub$off/ ratio of 10$\^$6/, reduced gate threshold voltage, and increased field effect mobility by three orders.

• Journal of the Korean Home Economics Association
• /
• v.29 no.4
• /
• pp.65-80
• /
• 1991

The present study was designed to find out demanding characteristics about a desk in the teenager's housing lifestyles. Documentry research and questionnaire survey methods were used in this study. Questionnaire were administered to 233 teenagers in seoul. Data were analyzed with the use SPSS PC+ package. The statistics were frequency, percentage, factor analysis, chi-squre, and cluster analysis. The major findings were followings: the teenager's housing lifestyles were categorized into the five patterns: the creative and impulsive type, the personal and private type, the economic and traditional type, the Western lifestyle-type, functional and achievement-orienented type. Teenagers in the low class of the functional and achievemental type demanded for the desk of the strong structure and materials, under 200,000 wons, and D furniture. Teenagers in the middle-high class of the personal and private type demanded for the desk of colorful and good design, 200,000-400,000 wons, and DS furniture. Teenagers in the high-low class of the Western lifestyle-type demanded for the desk of the famous trademark, 400,000-600,000 wons and S furniture. Teenagers in the middle-low class of the economic and tradition-oriented type demanded for the desk of the convinient and functional design, under 200,000 wons, and L furniture.

• Journal of Electrical Engineering and Technology
• /
• v.7 no.6
• /
• pp.932-939
• /
• 2012

This paper presents an equivalent circuit model of a LIPB (Li-Ion Polymer battery) for Hybrid Electric Vehicles (HEVs). The proposed equivalent circuit can be used to predict the charging/discharging characteristics in time domain as well as the impedance characteristic analysis in frequency domain. Based on these features, a one-cell model is established as a function of Depth of Discharge (DoD), and a 48-cell model for a battery pack was also established. It was confirmed by experiment that the proposed model predict the discharging and impedance (AC) characteristics quite accurately at different constant current levels. To check the usefulness of the proposed circuit, the model was used to simulate a motor driving circuit with an Insulated Gate Bipolar Transistor (IGBT) inverter and Brushless DC (BLDC) motor, and it is confirmed that the model can calculate the battery voltage fluctuation in time domain at different DoDs.