• Aerospace Engineering and Technology
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• v.3 no.2
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• pp.20-24
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• 2004

In this paper, a pattern/position tolerance analysis is visited on the insert to mount spacecraft electronic equipment. SQP(Sequential Quadratic Programming) is used to obtain the position tolerance. For examples, the cases of RDU(Remote Drive Unit) and OBC(On Board Computer) in the KOMPSAT-2 STM(Structure and Thermal Model) are analyzed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.78-81
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• 2002

Printed Circuit Boards for satellite are composed of multi-layered copper plate and glass epoxy. Each copper layer have the complicated and different pattern to operate correctly for its mission. Especially. copper layer give effect on the PCB stiffness seriously. But It can make more complicate to predict the exact stiffness of PCB. In KOMPSAT-2 program, too many type of PCB are used for each electronic unit, and they have different type of pattern of copper layer. Solar array regulator has two type of PCB and it will be considered for this study. In this study. we calculate the PCB board stiffness of KOMPSAT-2 SAR unit considering the concept of simplified representative volume element. It will be correlated with the test results under KOMPSAT-2 vibration environmental condition to increase the reliability of this study.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.2
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• pp.137-143
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• 2008

High voltage MLCCs with C0G temperature coefficient characteristics could apply DC-DC invertor were investigated for its dielectric properties. Also we manufactured MLCC through various process and studied the characteristics of dielectric break down voltage [BDV] and dielectric property as the variation of thickness in the green sheet and how to pattern the internal electrode. As the thickness of green sheet is increase, the dielectric BDV per unit thickness is decreased. But as the pattern of internal electrodes were floated we could manufacture the high voltage MLCC maintained its dielectric BDV a unit.

• Journal of the Korean Society of Safety
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• v.27 no.6
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• pp.31-42
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• 2012

Urban transit vehicle that uses electrical energy, is faster, safer and energy-efficient public transit than other means. As a Research method, the Matlab/Simulink are used to modeling a regenerative brake-capable train, and actual parameters such as powering and braking characteristics, all kinds of resistance, passenger load, velocity, gradient, radius of curve etc and powering and breaking commands per time or distance are inputted to train's dynamic equation, then a simulation program is made and used to yield train driving pattern and driving time and the amount of driving energy used thereby at auto and manual operation and at all sector.

• Journal of information and communication convergence engineering
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• v.3 no.1
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• pp.28-32
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• 2005

In this paper, we propose a novel test method to effectively detect hard and soft faults in CMOS 2-stage op-amps. The proposed method uses a very high frequency sinusoidal signal that exceeds unit gain bandwidth to maximize the fault effects. Since the proposed test method doesn't require any complex algorithms to generate the test pattern and uses only a single test pattern to detect all target faults, therefore test costs can be much reduced. The area overhead is also very small because the CUT is converted to a unit gain amplifier. Using HSPICE simulation, the results indicated a high degree of fault coverage for hard and soft faults in CMOS 2-stage op-amps. To verify this proposed method, we fabricated a CMOS op-amp that contained various short and open faults through the Hyundai 0.65-um 2-poly 2-metal CMOS process. Experimental results for the fabricated chip have shown that the proposed test method can effectively detect hard and soft faults in CMOS op-amps.

• Proceedings of the Korean Reliability Society Conference
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• 2005.06a
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• pp.121-129
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• 2005

In this paper, we consider a periodic preventive maintenance(PM) policy in which each PM reduces the hazard rate of amount proportional to the failure intensity, which increases since the last PM and slows down the wear-out speed to that of new one. And the proportion of reduction in hazard rate decreases with the number of PMs. Our model is similar to $ARI_1$ proposed by Doyen and Gaudoin(2004) in the sense of reduction of hazard rate. Our model has totally different wear-out pattern of hazard rate after PM's, however, and the proportion of reduction depends on the number of PM's. Assuming that the system undergoes only minimal repairs at failures between PM's, the expected cost rate per unit time is obtained. The optimal number N of PM and the optimal period x, which minimize the expected cost rate per unit time are discussed. Explicit solutions for the optimal periodic PM are given for the Weibull distribution case.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.1337-1340
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• 2016

Background: There is a noticeable change in the approach with which women nowadays seek help for diseases like breast cancer, primarily due to awareness campaigns, but what happens after surgical procedures is of great significance too. This study focused on the several psychological connotations attached to mastectomy and how the patients cope. Objective: To understand the pattern of anxiety and level of depression among Pakistani patients undergoing mastectomy. Materials and Methods: The sample size consisted of 88 patients who had undergone mastectomy at the different surgical units of the Civil Hospital, Karachi, from January 2012-December 2014; The questionnaire was administered before they were discharged i.e. within 3 days of surgical procedures. The patients were asked if they were willing to participate in this study, those who agreed signed the consent form and then we preceded by asking questions with a standardized tool. A self made questionnaire was constructed keeping in mind the nature and specification of the disease, which consisted of 20 questions related to anxiety and depression, focusing on a mixture of psychological and physiological symptoms. Results: There were a total of 88 patients out of which 36 (41%) were aged 51 to 60 years, 24 (27.2%) of the patients were in the age category of 41 to 50 years, 17 aged 61 and above (19.3%) and only 11 (12.5%) 30-40 years of age, the youngest of all the age categories. The pattern of depression and anxiety was found to be similar among all age categories, severe depression and anxiety predominating over moderate level of such symptoms, with only relatively few patients sufering mild or no depression symptoms. Conclusions: It was concluded that going through mastectomy leads to moderate to severe levels of depression and anxiety, primarily because the females feel incomplete and insecure after losing a part of themselves.

• Journal of Korean Society of Rural Planning
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• v.24 no.1
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• pp.1-10
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• 2018

This study is to evaluate the per capita accessibility to child care facilities using road map in rural village unit considering the supply and demand of child care facilities in municipal (Si-Gun) units. Using these estimated accessibility, the most accessible regions to child care facilities was identifies using Moran's index. Assuming establish a new child care facility in the most accessible region, the sensitivity of child care environment was analyzed. The number of regions are 71 si-gun-gu where supply of child care facilities is insufficient. The average accessibility per capita is 1.09 km to child care facilities and the average accessibility in Myeon unit is approximately 2.2 times higher than accessibility in Eup unit (Eup unit 0.54 km, Myeon unit 1.21 km). Approach tendency from village to child care facilities has positive relationship as 0.451 global Moran's index. The high-high (H-H) accessibility regions are wide as Gangwon-do, Gyeongsangbuk-do, Gyeongsangnam-do, Jeollanam-do and Chungcheongbuk-do. Assumed to be established the new child care facilities in Yangyang-gun (Ganwon-do), accessibility changes of child care environment are up to 2.7 times greater and the recipient population is 77% of Yangyang-gun.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.647-653
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• 2022

Data mining is a technique that explores knowledge such as relationships and patterns between data by exploring and analyzing data. Data that occurs in the real world includes a temporal attribute. Temporal data mining research to find useful knowledge from data with temporal properties can be effectively utilized for predictive judgment that can predict the future. In this paper, we propose an algorithm using time-unit grouping to classify the database into regular time period units and discover frequent pattern itemsets in time units. The proposed algorithm organizes the transaction and items included in the time unit into a matrix, and discovers frequent items in the time unit through grouping. In the experimental results for the performance evaluation, it was found that the execution time was 1.2 times that of the existing algorithm, but more than twice the frequent pattern itemsets were discovered.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.1
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• pp.100-105
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• 2003

In this paper, we propose the novel test method effectively to detect short and open faults in CMOS op-amp. The proposed method uses a sinusoidal signal with higher frequency than unit gain bandwidth. Since the proposed test method doesn't need complex algorithm to generate test pattern, the time of test pattern generation is short, and test cost is reduced because a single test pattern is able to detect all target faults. To verify the proposed method, CMOS two-stage operational amplifier with short and open faults is designed and the simulation results of HSPICE for the circuit have shown that the proposed test method can detect short and open faults in CMOS op-amp.