• Journal of Korean Society for Quality Management
• /
• v.26 no.4
• /
• pp.51-64
• /
• 1998

Mean shifts may be found in tool wear in machining, drawing, stamping and moulding operations, which make the process quality level deteriorate over time. In such situations, it is necessary to reset or readjust the manufacturing process at regular time basis or by inspection to prevent defective items produced. Although the deterioration rate may be assumed to be linear in a production cycle, there are many cases where the rate varies after resetting due to the variation of tool characteristics or by using the resharpened tools. In such cases, the deterioration rate should not be assumed to be a deterministic constant but a random variable. This paper is to find an optimal resetting period and quality level for such production processes.

• Communications for Statistical Applications and Methods
• /
• v.7 no.2
• /
• pp.435-446
• /
• 2000

Statistical process control(SPC) and engineering process control(EPC) are two strategies for quality improvement that have been developed independently. EPC seeks to minimize variability by adjusting compensatory variables in order to make the process level close to the target, while SPC seeks to reduce variability by monitoring and eliminating causes of variation. One purpose of this paper is to propose the IMA(0,1,1) model as the in-control process model. For the out-of-control process model we consider two cases; one is the case with a step shift in the level, and the other is the case with a change in the nonstationarity. Another purpose is to suggest the use of an integrated process control procedure with adjustment and monitoring, which can consider the proposed process model effectively. An integrated control procedure will improve the process control activity significantly for cases of the proposed model, when compared to the procedure of using either EPC or SPC, since EPC will keep the process close to the target and SPC will eliminate special causes.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08b
• /
• pp.1172-1175
• /
• 2007

We have investigated the threshold voltage shifts(${\Delta}Vth$) and drain current level shift (${\Delta}Ids$) in subthreshold region of a-Si:H TFTs induced by DC Bias (Vgs and Vds) - Temperature stress (BTS) condition. We plotted the transfer curves and the ${\Delta}Vth$ contour maps as Vds-Vds stress bias and Temperature to examine the severe damage cases on TFTs. Also, by drawing out the time-dependent transfer curve (Ids-Vgs) in the region of $10^{-8}\;{\sim}\;10^{-13}$ (A) current level, we can estimate the failure time of TFTs in a operating condition.

• Journal of the Microelectronics and Packaging Society
• /
• v.22 no.1
• /
• pp.27-34
• /
• 2015

The correlation between crack propagation and localized recrystallization are compared in a series of cross section analyses on thermal cycled edgebond and underfilm material applied wafer level chip scale package (WLCSP) components with a baseline of no-material applied WLCSP components. The results show that the crack propagation distribution and recrystallization region correlation can explain potential degradation mechanisms and support the damage accumulation history in a more efficient way. Edgebond material applied components show a shift of damage accumulation to a more localized region, thus potentially accelerated the degradation during thermal cycling. Underfilm material applied components triggered more solder joints for a more wider distribution of damage accumulation resulting in a slightly improved thermal cycling performance compared to no-material applied components. Using an analysis on localized distribution of recrystallized areas inside the solder joint showed potential value as a new analytical approach.

• Journal of Power Electronics
• /
• v.13 no.5
• /
• pp.779-786
• /
• 2013

A highly efficient sustaining driver is proposed for plasma display panels (PDPs). When the PDP is charged and discharged, the proposed sustaining driver employs an address voltage source used in an addressing period. A voltage source is used for fully charging the panel to the sustaining voltage, and an initial inductor current helps the panel discharge to 0 V. The resonance between the panel and an inductor is made by shifting the voltage and current bias level when charging and discharging the panel. As a result, the proposed circuit can reduce power consumption, switching loss, heat dissipation, and production cost. Experimental results of a 42-inch PDP are provided to verify the operation and features of the proposed circuit.

• Journal of Korean Public Health Nursing
• /
• v.27 no.1
• /
• pp.129-141
• /
• 2013

Purpose: This study examine the relationships retirement plans, perception of successful aging and attitude toward retirement nurses. Methods: The subjects of this study 200 nurses at two hospitals in C City. The data collection period from Nov. 1 to Dec. 31, 2011. Results: The degree of retirement significant according to age, marital status, education level, dependent, duration of employment, shift, department, annual salary. he degree of economic retirement plan showed significant differences according to age, marital status, education level, dependent home, duration of employment, department, annual salary. he degree of physical retirement plan showed statistically significant differences according to age, marital status, dependent, department. The degree of emotional retirement plan showed significant differences according to age, department. Conclusion: mprove the retirement of clinical nurse, we need a systematic based on physical and mental health.

• Journal of the Ergonomics Society of Korea
• /
• v.29 no.4
• /
• pp.553-561
• /
• 2010

This paper discusses the next direction for user experience design to keep pace with an ongoing IT paradigm shift, particularly focused on UX standardization activity contributing to reinforcement of brand power and customer loyalty. The paper introduces a model that identifies four levels of UX standardization and a key concept called "sustainable UX ecosystem" as its top level. It argues that in the new IT paradigm the fourth level of UX standardization, the sustainable UX ecosystem, is the next direction user experience must head towards.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.916-917
• /
• 2008

In this paper, Switching damage of switches that is used to proposed power conversion system is reduced by soft switching way. dissipation by part resonance and my resonance stress for resonance of resonance circuit are decreased. Is acted by conversion system high effectiveness. Have following characteristic. Design snubber circuit that is used by switch protection in existent hard work rate Topology by resonant circuit for sogt switching, circuit structure was simple and control system is easy. Also, Can generate free output voltage by multi level Tuesday of output that use individuation Power Cell's Phase Shift PWM, and Low-end switching frequency the harmonic is few.

• Journal of Trauma and Injury
• /
• v.25 no.4
• /
• pp.275-277
• /
• 2012

An eipdural hematoma in an infant is a very rare entity. We report a case of an acute traumatic intracranial epidural hematoma that developed with a lucid interval in a 4-month-old infant after a fall down from a bed. The infant was admitted at the emergency room. The child had initially cried and may have had a decreased level of consciouseness due to brain injury, but then returned to normal level of consciousness for several hours prior to admission. However, the infant had vomited twice after taking milk and then was lethargic. The brain CT revealed a lentiform-shaped huge hematoma on the right parietal area with a midline shift of 8 mm. An osteoplastic craniotomy was performed, and the intracranial epidural hematoma was totally removed. Postoperatively, the infant recovered well and was dischaged.

• Journal of the Semiconductor & Display Technology
• /
• v.5 no.3 s.16
• /
• pp.11-16
• /
• 2006

A low cost PDP sustain power supply is proposed based on flyback topology. By using Boundary Conduction Method(BCM) to control input current regulation, DCM condition can be met under all load conditions. Another feature of the proposed method is that a excessive voltage stress due to the link voltage increase can be suppressed by removing link capacitor and suggest new 'Level-shifting switch driver'. this new gate driver is improved 66% of efficiency than switching loss of a existed push-pull amplifier. The proposed converter is tested with a 400W(200V-2A output) prototype circuit.