• Advances in concrete construction
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• v.14 no.1
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• pp.57-70
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• 2022

The spiral case concrete (SCC) used in the underground powerhouse of large hydropower stations is complex, difficult to pour, and has high requirements for temperature control and crack prevention. In this study, based on the closed-loop control theory of "multi-source sensing, real analysis, and intelligent control", a new intelligent cooling control system (ICCS) suitable for the SCC is developed and is further applied to the Wudongde large-scale underground powerhouse. By employing the site monitoring data, numerical simulation, and field investigation, the temperature control quality of the SCC is evaluated. The results show that the target temperature control curve can be accurately tracked, and the temperature control indicators such as the maximum temperature can meet the design requirements by adopting the ICCS. Moreover, the numerical results and site investigation indicate that a safety factor of the spiral case structure was sure, and no cracking was found in the concrete blocks, by which the effectiveness of the system for improving the quality of temperature control of the SCC is verified. Finally, an intelligent cooling control procedure suitable for the SCC is proposed, which can provide a reference for improving the design and construction level for similar projects.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10c
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• pp.75-77
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• 1998

Perhaps one of the most versatile approaches to learning in practical domains lies in case based reasoning. To date, however, most case based reasoning systems have tended to focus on relatively simple domains. The current study involves the development of a decision support system for a complex production process with a limited database. This paper presents a set of critical issues underlying CBR, then explores their consequences for a complex domain. Finally, the performance of the system is examined for resolving various types of quality control problems.

• Genomics & Informatics
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• v.10 no.2
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• pp.117-122
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• 2012

A sample size with sufficient statistical power is critical to the success of genetic association studies to detect causal genes of human complex diseases. Genome-wide association studies require much larger sample sizes to achieve an adequate statistical power. We estimated the statistical power with increasing numbers of markers analyzed and compared the sample sizes that were required in case-control studies and case-parent studies. We computed the effective sample size and statistical power using Genetic Power Calculator. An analysis using a larger number of markers requires a larger sample size. Testing a single-nucleotide polymorphism (SNP) marker requires 248 cases, while testing 500,000 SNPs and 1 million markers requires 1,206 cases and 1,255 cases, respectively, under the assumption of an odds ratio of 2, 5% disease prevalence, 5% minor allele frequency, complete linkage disequilibrium (LD), 1:1 case/control ratio, and a 5% error rate in an allelic test. Under a dominant model, a smaller sample size is required to achieve 80% power than other genetic models. We found that a much lower sample size was required with a strong effect size, common SNP, and increased LD. In addition, studying a common disease in a case-control study of a 1:4 case-control ratio is one way to achieve higher statistical power. We also found that case-parent studies require more samples than case-control studies. Although we have not covered all plausible cases in study design, the estimates of sample size and statistical power computed under various assumptions in this study may be useful to determine the sample size in designing a population-based genetic association study.

• Smart Structures and Systems
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• v.10 no.1
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• pp.33-46
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• 2012

To reduce the vibration of cable-stayed bridges, conventional magnetorheological (MR) damper control system (CMRDS), with separate power supply, sensors and controllers, is widely investigated. In this paper, to improve the reliability and performance of the control system, one adaptive MR damper control system (AMRDS) consisting of MR damper and piezoelectric energy harvester (PEH) is proposed. According to piezoelectric effect, PEH can produce energy for powering MR damper. The energy is proportional to the product of the cable displacement and velocity. Due to the damping force changing with the energy, the new system can be adjustable to reduce the cable vibration. Compared with CMRDS, the new system is structurally simplified, replacing external sensor, power supply and controller with PEH. In the paper, taking the N26 cable of Shandong Binzhou Yellow River Bridge as example, the design method for the whole AMRDS is given, and simple formulas for PEH are derived. To verify the effectiveness of the proposed adaptive control system, the performance is compared with active control case and simple Bang-Bang semi-active control case. It is shown that AMRDS is better than simple Bang-Bang semi-active control case, and still needed to be improved in comparison with active control case.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.273-276
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• 1987

This paper presents a case-building algorithm which can control the design variables of which some variables are designated as the input (known) variables and the remainders are defined as the output (unknown) variables. The case-building algorithm can enhance the design ability by categorizing design case automatically. Common CAD programs for analysis and design of machine elements use a case-selection technique where a programmer set initially a few of design cases and users can only choose one of given cases. This paper also demonstrates the case-building algorithm by applying into CAD programs for power-screw design.

• Proceedings of the IEEK Conference
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• 2001.06e
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• pp.29-32
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• 2001

This paper presents matrix inequality conditions for H$_2$optimal control of linear time-invariant descriptor systems in continuous and discrete time cases, respectively. First, the necessary and sufficient condition for H$_2$control and H$_2$controller design method are expressed in terms of LMls(linear matrix inequalities) with no equality constraints in continuous time case. Next, the sufficient condition for H$_2$control and H$_2$controller design method are proposed by matrix inequality approach in discrete time case. A numerical example is given in each case.

• Korean Journal of Health Education and Promotion
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• v.27 no.1
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• pp.49-60
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• 2010

Objectives: The purpose was to evaluate the effectiveness of participatory road safety education program for the lower grade in elementary schools. This program was developed based on the Activated Health Education model. Methods: Study design was compromise experimental group pre-post design. 456 students in 8 schools were nonrandomly assigned to study group(n=224) or control(n=232). The students finished self-administered questionnaire before and after education. Collected data was analyzed by using the SPSS. Results: 1. The common relevant factors in road safety knowledge and attitude were 'residential state' and 'experience of traffic accident'. 2. The knowledge showed that the case and control scored at 6.48 and 6.41 points before. After this intervention, the case and control scored at 8.38 and 6.51. The difference of the case was significant(p<0.001). 3. The attitude showed that the case and control scored at 19.67 and 19.63 before. After this, the case and control scored at 19.86 and 19.63. The difference of the case was significant(p<0.05). Conclusion: In order to implement the road safety education, children's socio-demographic characteristics were considered. Because this education was effective in both improving knowledge and attitude and bringing interest, various participatory program will be applied in road safety education for children.

• Journal of Pharmacopuncture
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• v.24 no.2
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• pp.54-58
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• 2021

Objectives: The purpose of this study is to investigate the effects of aerobic exercise and acupuncture treatment in obese patients. Methods: The effects of exercise in obese patients receiving acupuncture therapy were investigated in this retrospective, case-controlled study in which subjects complying with exercise were enrolled in the case and non-compliers were enrolled in the control group. Results: There was a statically significant weight loss in both the study case group (94.39 ± 20.36; 88.91 ± 19.00; n = 22; p = 0.001) and the control group (103.18 ± 21.92; 99.56 ± 21.92; n = 34; p = 0.001) after 3 months. Weight loss occurred in all 22 patients in the case group. In the control group, while weight loss occurred in 27 of the 34 patients, weight gain occurred in three patients. Conclusion: In conclusion, the addition of modalities such as acupuncture, exercise and diet may provide effective improvement in weight control.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.3
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• pp.165-168
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• 2000

Improvement on the switching characteristic of IGBT by means of the uniform and local lifetime control is studied numerically using two-dimensional simulator, MEDICI. In the case of uniform lifetime control, the on-state and switching characteristics are simulated as a function of lifetime, and compared with the experimental results reported, which allows a relationship between dose of electron irradiation and controlled lifetime. In the case of local lifetime control, simulations are carried out by varying the position, width, and lifetime of the locally controlled region, and the results are compared with the characteristics for the case of the uniform lifetime control. The turn-off time of the device with an optimized locally controlled region is found to decrease from about $4.5\mus$ to 0.11$mutextrm{s}$ while the forward voltage drop increases from 1.37V to 2.61V in comparison with that for the uniform lifetime control.

• Journal of Microbiology
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• v.44 no.4
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• pp.457-460
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• 2006

A suspicious meningococcal meningitis death case was reported to the Beijing CDC. The blood specimen was analyzed via multi-PCR and MLST. 6 isolates from close contacts were analyzed via PFGE and MLST. According to the results of the above analyses, the cause of this case was identified as a serogroup A Neisseria meningitidis, which, in terms of sequence typing, belonged the ST7 group.