• Journal of the Earthquake Engineering Society of Korea
• /
• v.14 no.2
• /
• pp.1-13
• /
• 2010

This paper proposes an optimal design method for the nonlinear seismic isolated bridge. The probabilities of failure at the pier and the seismic isolator are considered as objective functions for optimal design, and a multi-objective optimization technique is employed to efficiently explore a set of multiple solutions optimizing mutually-conflicting objective functions at the same time. In addition, a stochastic linearization method is incorporated into the multi-objective optimization framework in order to effectively estimate the stochastic responses of the bridge without performing numerous nonlinear time history analyses during the optimization process. As a numerical example to demonstrate the efficiency of the proposed method, the Nam-Han river bridge is taken into account, and the proposed method and the existing life-cycle-cost based design method are both applied for the purpose of comparing their seismic performances. The comparative results demonstrate that the proposed method not only shows better seismic performance but also is more economical than the existing cost-based design method. The proposed method is also proven to guarantee improved performance under variations in seismic intensity, in bandwidth and in the predominant frequency of the seismic event.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.9
• /
• pp.57-66
• /
• 2014

This paper presents a low-complexity barrel distortion correction processor for wide-angle cameras. The proposed processor performs the barrel distortion correction jointly with the color demosaicking, so that the hardware complexity can be reduced significantly. In addition, to reduce the required memory bandwidth, an efficient memory interface is proposed by utilizing the spatial locality of the memory access in the correction process. The proposed processor is implemented with 35K logic gates in a $0.11-{\mu}m$ CMOS process and its correction speed is 150 Mpixels/s at the operating frequency of 606MHz, where the supported frame size is $2048{\times}2048$ and the required memory bandwidth is 1 read/cycle.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.30 no.3
• /
• pp.215-222
• /
• 2017

In order to evaluate a stress state of concrete according to the change of tensile force of prestressed beam, improved nonlinear resonant ultrasonic spectroscopy(NRUS) method is proposed. This technique is advantageous to evaluate the stress state in initial state because the method shows much higher sensitivity than existing linear ultrasonic methods. The NRUS technique measure a nonlinearity parameter, which is calculated from the resonant frequency shift of ultrasonic wave related to the medium state, and the result is also closely related to the stress state of concrete. In this study, the nonlinearity parameter was measured with the change of tensile force to verify the close relationship between the two factors, and the effect of repetitive load cycle on the change of nonlinearity parameter was analyzed. In addition, sensitivity comparison with the linear ultrasonic pulse velocity method was performed. Through the experimental results, the possibility of NRUS technique for the evaluation of stress state in prestressed beam was confirmed.

• Journal of Korean Society of Forest Science
• /
• v.76 no.3
• /
• pp.193-199
• /
• 1987

Simple estimating method of rock drilling and blasting work size is necessary to apply as a guidance of general road plan and a cost analysis of mountain forest road construction. For this work study, 11 cycles were divided in 5km route at Hyeonnammeon Yangyang-gun and the mountain slope at every 20m interval was measured. During working days all kind of works concerned on drilling and blasting was investigated in every cycle. Depending on the simple work study results it's work size can bef estimated with high correlation between drilling length in meter and frequency percentage of mountain slope more than 70%. With total drilling length known the machinery hours, drillers and explosive quantify can be estimated by the regression with high correlation. Estimation of drilling and blasting work by mountain slope gradient in road route is proposed like table 5 with estimating value of machinery hour, drillers and explosive in granite gneiss region.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.14 no.6
• /
• pp.457-465
• /
• 2009

Lithium batteries are widely used in mobile electronic devices due to their higher voltage and energy density, lighter weight and longer life cycle compared to other secondary batteries. In particular, high demand for lithium batteries is expected for electric cars. In case of lithium batteries used in electric cars, driving distance must be calculated accurately and discharging should not be done below the level of making it impossible to crank. Therefore, accurate information about state of charge (SOC) becomes an essential element for reliable driving. In this paper, a new method of estimating the SOC of lithium polymer batteries by using AC impedance is proposed. In the proposed method, parameters are extracted by fitting a curve of impedance measured at each frequency on the equivalent impedance model and extracted parameters are used to estimate SOC. Experiments were conducted on lithium polymer batteries with similar capacities made by different manufacturers to prove the validity of the proposed method.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.31 no.1 s.256
• /
• pp.26-35
• /
• 2007

The vehicle of urban transit is a complex system that consists of various electric, electronic, and mechanical equipments, and the maintenance cost of this complex and large-scale system generally occupies sixty percent of the LCC (Life Cycle Cost). For reasonable establishing of maintenance strategies, safety security and cost limitation must be considered at the same time. The concept of system reliability has been introduced and optimized as the key of reasonable maintenance strategies. For optimization, three preceding studies were accomplished; standardizing a maintenance classification, constructing RBD (Reliability Block Diagram) of VVVF (Variable Voltage Variable Frequency) urban transit, and developing a web based reliability evaluation system. Historical maintenance data in terms of reliability index can be derived from the web based reliability evaluation system. In this paper, we propose applying inverse problem analysis method and hybrid neuro-genetic algorithm to system reliability optimization for using historical maintenance data in database of web based system. Feed-forward multi-layer neural networks trained by back propagation are used to find out the relationship between several component reliability (input) and system reliability (output) of structural system. The inverse problem can be formulated by using neural network. One of the neural network training algorithms, the back propagation algorithm, can attain stable and quick convergence during training process. Genetic algorithm is used to find the minimum square error.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.15
• /
• pp.6215-6223
• /
• 2015

Tyrosine phosphorylation plays an important role in regulating human physiological and pathological processes. Functional stabilization of tyrosine phosphorylation largely contributes to the balanced, coordinated regulation of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). Research has revealed PTPs play an important suppressive role in carcinogenesis and progression by reversing oncoprotein functions. Receptor-type protein tyrosine phosphatase O (PTPRO) as one member of the PTPs family has also been identified to have some roles in tumor development. Some reports have shown PTPRO over-expression in tumors can not only inhibit the frequency of tumor cell division and induce tumor cell death, but also suppress migration. However, the tumor-suppression mechanisms are very complex and understanding is incomplete, which in some degree blocks the further development of PTPRO. Hence, in order to resolve this problem, we here have summarized research findings to draw meaningful conclusions. We found tumor-suppression mechanisms of PTPRO to be diverse, such as controlling G0/G1 of the tumor cell proliferation cycle, inhibiting substrate phosphorylation, down-regulating transcription activators and other activities. In clinical anticancer efforts, expression level of PTPRO in tumors can not only serve as a biomarker to monitor the prognosis of patients, but act as an epigenetic biomarker for noninvasive diagnosis. In addition, the re-activation of PTPRO in tumor tissues, not only can induce tumor volume reduction, but also enhance the susceptibility to chemotherapy drugs. So, we can propose that these research findings of PTPRO will not only support new study ideas and directions for other tumor-suppressors, importantly, but also supply a theoretical basis for researching new molecular targeting agents in the future.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.4
• /
• pp.1209-1215
• /
• 2012

Background and Aim: Oxaliplatin hypersensitivity is a well-known adverse reaction but the prevalence varies and data for frequency and clinical features have not been reported for Korea. Here we evaluates the prevalence and risk factors for hypersensitivity reactions to oxaliplatin after chemotherapy. Methods: Clinical information on all patients treated with oxaliplatin was retrospectively reviewed in electronic medical records between August 2009 and July 2010 in Seoul National University Bundang Hospital. Patients who experienced hypersensitivity reactions to oxaliplatin were compared with those who did not. Results: A total of 393 patients received oxaliplatin, with 42 (10.7%) experiencing hypersensitivity reactions including three cases of anaphylaxis. Median cycle of the first hypersensitivity reaction was 8. Reactions correlated with lower dexamethasone doses. Other variables were not significant. Conclusions: The prevalence of hypersensitivity reactions was 10.7%, symptoms being mostly mild and cutaneous. Lower dexamethasone doses could be a predictor for hypersensitivity reactions to oxaliplatin.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.17
• /
• pp.7181-7185
• /
• 2014

Cyclin D1 is an important positive regulator of the G1/S phase of the cell cycle. We investigated the association between the CCND1 G870A polymorphism and susceptibility to papillary thyroid cancer in Turkish people. This study covered 102 patients with papillary thyroid cancer and 174 healthy controls. CCND1 genotyping was determined by the PCR-RFLP method. We found that the A allele frequency was higher in the cases than in the controls (p=0.042). On stratification analysis, papillary thyroid cancer risk was significantly elevated in individuals older than 45 years with the A allele (OR=1.91, 95% CI, 1.09-3.35, p=0.024) and in females with the A allele (OR=1.73, 95% CI, 1.06-2.84, p=0.029), compared to the G allele. According to the subject age, there was an increased papillary thyroid cancer risk for the individuals older than 45 years with the AA genotype (OR=2.28, 95% CI, 1.02-5.13, p=0.046) compared to the AG+GG combined genotypes. In conclusion, it is suggested that the CCND1 G870A polymorphism may contribute to the susceptibility to papillary thyroid cancer, especially in those who were older subjects ($45{\leq}$ years old) and female, in the Turkish population.

• Journal of the Microelectronics and Packaging Society
• /
• v.15 no.1
• /
• pp.7-18
• /
• 2008

This paper reviews the current development of an ultra-slim SiP for Radio Frequency (RF) application, in which three flip chips, additional passive components and Surface Acoustic Wave (SAW) filters are integrated side-by-side. A systematic investigation is carried out for the design optimization, process and reliability improvement of the package, which comprises several aspects: a design study based on the 3D thermo-mechanical finite element analysis of the packaging, the determination of stress, warpage distribution, critical failure zones, and the figuration of the effects of material properties, process conditions on the reliability of package. The optimized material sets for manufacturing process were determined which can reduce the number of testing samples from 75 to 2. In addition the molded underfilling (MUF) process is proposed which not only saves one manufacturing process, but also improves the thermo-mechanical performance of the package compared with conventional epoxy underfilling process. In the end, JEDEC's moisture sensitivity test, thermal cycle test and pressure cooker tests have also been carried out for reliability evaluation. The test results show that the optimized ultra-slim SiP has a good reliability performance.