• Smart Structures and Systems
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• 제29권4호
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• pp.549-560
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• 2022

The optimum damping and tuning frequency ratio of the tuned mass damper-inerter (TMDI) for the base-isolated structure is obtained using the numerical searching technique under stationary white-noise and filtered white-noise earthquake excitation. The minimization of the isolated structure's mean-square relative displacement and absolute acceleration, as well as the maximization of the energy dissipation index, were chosen as the criteria for optimality. Using a curve-fitting technique, explicit formulae for TMDI damping and tuning frequency for white-noise excitation are then derived. The proposed empirical expressions for TMDI parameters are found to have a negligible error, making them useful for the effective design of base-isolated structures. The effectiveness of TMDI and its optimum parameters are influenced by the soil condition and isolation frequency, according to the comparison made of the optimized parameters and response with different soil profiles. The effectiveness of an optimally designed TMDI in controlling the displacement and acceleration response of the flexible isolated structure under real and pulse-type earthquakes is also observed and found to be increased as the inertance mass ratio increases.

• Structural Engineering and Mechanics
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• 제83권3호
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• pp.327-340
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• 2022

The Collapse Margin Ratio (CMR) is a notable index used for seismic assessment of the structures. As proposed by FEMA P695, a set of analyses including the Nonlinear Static Analysis (NSA), Incremental Dynamic Analysis (IDA), together with Fragility Analysis, which are typically time-taking and computationally unaffordable, need to be conducted, so that the CMR could be obtained. To address this issue and to achieve a quick and efficient method to estimate the CMR, the Artificial Neural Network (ANN), Response Surface Method (RSM), and Adaptive Neuro-Fuzzy Inference System (ANFIS) will be introduced in the current research. Accordingly, using the NSA results, an attempt was made to find a fast and efficient approach to derive the CMR. To this end, 5016 IDA analyses based on FEMA P695 methodology on 114 various Reinforced Concrete (RC) frames with 1 to 12 stories have been carried out. In this respect, five parameters have been used as the independent and desired inputs of the systems. On the other hand, the CMR is regarded as the output of the systems. Accordingly, a double hidden layer neural network with Levenberg-Marquardt training and learning algorithm was taken into account. Moreover, in the RSM approach, the quadratic system incorporating 20 parameters was implemented. Correspondingly, the Analysis of Variance (ANOVA) has been employed to discuss the results taken from the developed model. Additionally, the essential parameters and interactions are extracted, and input parameters are sorted according to their importance. Moreover, the ANFIS using Takagi-Sugeno fuzzy system was employed. Finally, all methods were compared, and the effective parameters and associated relationships were extracted. In contrast to the other approaches, the ANFIS provided the best efficiency and high accuracy with the minimum desired errors. Comparatively, it was obtained that the ANN method is more effective than the RSM and has a higher regression coefficient and lower statistical errors.

• Clinical and Experimental Reproductive Medicine
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• 제49권1호
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• pp.49-56
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• 2022

Objective: Oxidative stress and sperm DNA fragmentation (SDF) have been linked to idiopathic male infertility (IMI). Various antioxidants have been tried to improve semen parameters and fertility potential in IMI patients, but with inconsistent results. The study aimed to compare the effects of coenzyme Q10 (CoQ10) and Centrum multivitamins on semen parameters, seminal antioxidant capacity, and SDF in infertile men with idiopathic oligoasthenospermia (OA). Methods: This prospective controlled clinical study involved 130 patients with idiopathic OA and 58 fertile controls. The patients were divided randomly into two groups: the first group received CoQ10 (200 mg/day orally) and the second group received Centrum multivitamins (1 tablet/day) for 3 months. Semen parameters, CoQ10 levels, reactive oxygen species (ROS), total antioxidant capacity (TAC), catalase, SDF, and serum hormone levels (follicle-stimulating hormone, luteinizing hormone, testosterone, and prolactin) were compared at baseline and after 3 months. Results: Both CoQ10 and Centrum improved sperm concentration and motility, but the improvement was greater with Centrum therapy (p<0.05). Similarly, both therapies improved antioxidant capacity, but TAC and catalase improvement was greater (p<0.01 and p<0.001 respectively) with CoQ10, whereas ROS (p<0.01) and SDF (p<0.001) improvements were greater with Centrum administration. Centrum therapy was associated with reduced serum testosterone (p<0.05). Conclusion: In conclusion, both CoQ10 and Centrum were effective in improving semen parameters, antioxidant capacity, and SDF, but the improvement was greater with Centrum than with CoQ10. Therefore, Centrum-as a source of combined antioxidants-may provide more effective results than individual antioxidants such as CoQ10 in the treatment of infertile men with idiopathic OA.

• 임상간호연구
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• 제15권3호
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• pp.5-16
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• 2009

Purpose: This study was done to provide effective nursing interventions using an individualized educational program designed to contribute to the knowledge, compliance and physiologic parameters (serum potassium, phosphorus and interdialytic weight gain) of non-compliant hemodialysis patients. Methods: There were 22 participants in the experimental group and 19 in the control group. Nurses with rapport with patients provided education to non-compliant hemodialysis patients for 20 minutes three times a week for six weeks. This education program consisted of individual consulting, telephones conversations regarding hemodialysis, and requests for patient support from patients' families and colleagues. Results: Hypothesis 1; "Knowledge about hemodialysis in the experimental group will be higher than the control. group" was not supported. Hypothesis 2; "Compliance will be higher in the experimental group than in the control group", and Hypothesis 3; "Physiologic parameters of experimental group will improve" were supported as serum potassium and interdialytic weight gain decreased, but results were not consistent for phosphorous. Conclusion: This program for non-compliant patients increased compliance and improved physiologic parameters. Therefore, this educational program should be effective as a nursing intervention.

• 대한기관식도과학회지
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• 제7권2호
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• pp.161-167
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• 2001

Background and Objectives： Total laryngectomy is often required for advanced cases. But this operation induced the many inconvenience of basic daily life. Early diagnosis of laryngeal cancer is very important to prevent from this disastrous condition. In this point of view, mass screening test for early detection of laryngeal cancer is necessary. Screening test using voice has many advantages such as simple, less interventional. Voice collection by Automatic Response System(ARS) is comfortable and easy to got acoustic sample. Thus author tried to got the acoustic parameters which can differentiate normal, benign. and malignant laryngeal diseases and also checked the availability of parameters on neural network system. Materials and Methods: Author has evaluated the voice from 17 laryngeal cancer patients and 45 benign laryngeal disease patients who visited at Department of Otolaryngology, Pusan National University Hospital from May 1998 to April 2001, and 15 normal control. Author chose the sir Parameters (Jitt. vFo, Shim, vAm, NHR, SPI) that was thought to be related with voice collected by ARS among thirty-three parameters analysed by a Multi-Dimensional Voice Program (MDVP). Two-step neural network was used for the availability of six parameters. Results: The detection rate of normal voice by ARS voice analysis is 78.5% and detection rate of abnormal voice was 97.1 o/o. Among abnormal voice, the detection rate of benign laryngeal diseases and laryngeal cancers were 82.4 o/o, 70.6% respectively. Conclusion: Author concluded that six parameters and Matlab based neural network software may be effective in development of acoustic screening system for laryngeal cancer and further study should be necessary for development of new acoustic parameters.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.44-48
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• 2000

Several parameters to represent the characteristics of the observed at the domestic networks from several earthquakes occurred in the Korean Peninsula. Parameters to fit most the multiple Fourier amplitude spectra of the observed accelerations are estimated. This study adopts the stochastic ground motion model referred to the BLWN mode in which the energy is distributed randomly over the duration of the source and which has proven to be very effective in modeling a wide range of ground motion observations. The stochastic ground motion model employed here uses an omega-squared ({{{{ omega ^2 }}) Brune source model with a single corner frequency and a constant stress drop,. The {{{{ omega ^2 }} source model has become a seismological standard because of its simplicity an ability to predict spectral amplitudes and shapes over an extremely broad ranges of magnitudes distances and from the inversion show very unstable based on the fact of high values of mean/median. These results may imply that more observed data and more precise site classification including accurate preparation analysis of data such as more accurate scaling from counts to kine are needed for more stable are effective inversion of Fourier amplitude spectrum of the observed ground motions.

• International Journal of Concrete Structures and Materials
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• 제6권3호
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• pp.177-186
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• 2012

The temperature distributions of concrete structures strongly depend on the value of thermal conductivity of concrete. However, the thermal conductivity of concrete varies according to the composition of the constituents and the temperature and moisture conditions of concrete, which cause difficulty in accurately predicting the thermal conductivity value in concrete. For this reason, in this study, back-propagation neural network models on the basis of experimental values carried out by previous researchers have been utilized to effectively account for the influence of these variables. The neural networks were trained by 124 data sets with eleven parameters: nine concrete composition parameters (the ratio of water-cement, the percentage of fine and coarse aggregate, and the unit weight of water, cement, fine aggregate, coarse aggregate, fly ash and silica fume) and two concrete state parameters (the temperature and water content of concrete). Finally, the trained neural network models were evaluated by applying to other 28 measured values not included in the training of the neural networks. The result indicated that the proposed method using a back-propagation neural algorithm was effective at predicting the thermal conductivity of concrete.

• 한국전자통신학회논문지
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• 제9권8호
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• pp.921-926
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• 2014

본 논문에서는 CSLR(Complementary Single Loop Resonator)을 이용한 인셋 급전 마이크로스트립 안테나의 특성에 대해 연구하였다. SLR(Single Loop Resonator) 단일 구조에서 시뮬레이션 셋업 과정을 통해 산란계수로부터 실효투자율을 계산하였으며, 실효투자율이 음의 값을 갖는 주파수에서 SLR 구조의 치수를 선택하였다. 그리고 인셋 급전된 마이크로스트립 안테나의 접지면에 SLR 구조의 쌍대 구조인 CSLR을 $3{\times}3$으로 배열하여 최적 안테나를 설계하였다. 설계한 안테나의 반사손실과 복사패턴을 구하였으며, 공진주파수 2.82 GHz에서 기존의 인셋 급전 안테나와 크기를 비교하면 면적 대비 약 56.8%가 감소하는 결과를 얻었다. 사용된 툴은 3차원 FEM 툴인 Ansoft사의 HFSS를 사용하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.910-915
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• 2004

The objective of this study is to investigate the influence of process parameters, such as power of laser, travel speed of laser and material thickness, on the practical cutting region and the kerfwidth for the case of cutting of CSP 1N sheet using high power Nd:YAG laser with continuous wave(CW). In order to find the practical cutting region and the relationship between process parameters on the kerfwidth, several laser cutting experiments are carried out. The effective heat input is introduced to consider the influence of power and travel speed of laser on the kerfwidth together. From the results of experiments, the allowable cutting region and the relationship between the effective heat input and kerfwidth for the case of cutting of CSP 1N sheet using high power CW Nd:YAG laser have been obtained to improve the dimensional accuracy of the cut area.

• Geomechanics and Engineering
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• 제15권6호
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• pp.1143-1151
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• 2018

Loess often causes problems when used as a filling material in the construction of foundations. Therefore, the compaction technique, shear behavior, and bearing capacity of a filled foundation should be carefully considered. A series of tests was performed in this study to obtain effective compaction techniques and construction parameters. The results indicated that loess is strongly sensitive to water. Thus, the soil moisture content should be kept within 12%-14% when it is used as a filling material. The vibrating-dynamic combination compaction technique is effective and has fewer limitations than other methods. In addition, the shear strength of the compacted loess was found to increase linearly with the degree of compaction, and the soil's compressibility decreased rapidly with an increase in the degree of compaction when the degree of compaction was less than 95%. Finally, the characteristic value of the bearing capacity increased with an increase in the degree of compaction in a ladder-type way when the degree of compaction was within 92%-95%. Based on the test data, this paper could be used as a reference in the selection of construction designs in similar engineering projects.