• Advances in concrete construction
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• v.6 no.3
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• pp.269-283
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• 2018

This study presents the effects of geometrical dimensions of concrete gravity dams on the seismic response considering different base width/dam height (L/H) ratios. In the study, a concrete gravity dam with the height of 200 m is selected and finite element models of the dam are constituted including five different L/H ratios such as 0.25, 0.5, 0.75, 1.00, 1.25. All dams are modeled in ANSYS software considering dam-reservoir-foundation interaction. 1989 Loma Prieta earthquake records are applied to models in upstream-downstream direction and linear time history analyses are performed. Dynamic equilibrium equations of motions obtained from the finite element models of the coupled systems are solved by using Newmark time integration algorithm. The seismic response of the models is evaluated from analyses presenting natural frequencies, mode shapes, displacements and principal stresses. The results show that the L/H ratios considerably affect the seismic response of gravity dams. Also, the model where L/H ratio is 1.00 has more desirable results and most appropriate representation of the seismic response of gravity dams.

• Earthquakes and Structures
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• v.13 no.2
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• pp.103-118
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• 2017

In vertical seismic isolation (VSI), a building is partitioned intentionally by vertical layers into two dynamically different substructures for seismic response reduction. Initially, a 1-story frame was partitioned into two substructures, interconnected by viscous and visco-elastic links, and seismic responses of the original and the vertically isolated structures (VIS) were obtained, considering a large number of stiffness and mass ratios of substructures with respect to the original structure. Color contour graphs were defined for presentation and investigation of large amounts of output results. Dynamic characteristics of the isolated structures were studied by considering the non-classical damping of the system, and then the effects of viscous and visco-elastic link parameters on the modal damping ratios were discussed. On this basis, three states of mass isolation, interactional state, and control mass were differentiated. Response history analyses were performed by Runge-Kutta numerical method. In these analyses, interaction of isolation ratios and link parameters, on response control of VIS was studied and the appropriate ranges for link parameters as well as the optimal ranges for isolation ratios were suggested. Results show that by using the VSI technique, seismic response reduction up to 50% in flexible substructure and even more in stiff substructure is achievable.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.6
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• pp.3881-3885
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• 2013

Objective: The objective of this study was to identify clinical predictive factors for tumor response after neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal cancer (LARC). Methods: All factors were evaluated in 88 patients with LARC treated with nCRT. After a long period of 4-8 weeks of chemoradiotherapy, 3 patients achieved clinical complete response (cCR) and thus aggressive surgery was avoided, and the remaining 85 patients underwent a curative-intent operation. The response to nCRT was evaluated by tumor regression grade (TRG) system. Results: There were 32 patients (36.4%) with good tumor regression (TRG 3-4) and 56 (63.6%) with poor tumor regression (TRG 0-2). Lymphocyte counts and ratios were higher in good response cases (P=0.01, 0.03, respectively) while neutrophil ratios and N/L ratios were higher in poor response cases (P=0.04, 0.02, respectively). High lymphocyte ratios before nCRT and good tumor regression (TRG3-4) were significantly associated with improved 5-year disease-free survival (P<0.05). Pretreatment nodal status was also significantly associated with 5-year disease-free survival and 5-year overall survival (P<0.05). Multivariate analysis confirmed that the pretreatment lymphocyte ratio and lymph nodal status were independent prognostic factors. Conclusion: Our study suggested that LARC patients with high lymphocyte ratios before nCRT would have good tumor response and high 5-year DFS and OS.

• Journal of the Korean Applied Science and Technology
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• v.21 no.2
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• pp.148-155
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• 2004

Response surface analysis was used to study dietary ratios of n-3/n-6 fatty acid and P/S to minimize plasma triglycerides, total cholesterol and LDL ${\cdot}$ VLDL-C levels and maximize plasma HDL ${\cdot}$ C levels of rats. Because the dietary components were not statistically independent, they were studied in combinations of two variables. The two-variable combinations were the most useful in locating the desired maximum or minimum plasma triglycerides, total cholesterol and LDL ${\cdot}$ VLDL-C response in terms of the proportions of the dietary components. Response surface contours and three dimensional plots were developed for each plasma lipid response. The contours and three dimensional plots were used to help determine those combinations of the dietary fatty acid ratios that would produce the desired minimum or maximum lpid responses. The statistical analyses indicated that the minimized plasma cholesterol response levels could be attained with a diet consisting of 2.26 n-3/n-6 fatty acid and 2.15 P/S ratios.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.109-114
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• 2002

The purpose of this study is to propose the general method for evaluating the equivalent damping ratios of a structure with supplemental response control dampers. We define Lyapunov function of which derivative can be expressed in autoregressive form and evaluate the equivalent damping ratios by using Lyapunov function and its derivative. This Lyapunov function may be called as generalized structural energy. In this study, it is assumed that the response of a structure is stationary random process and control dampers do not affect the modal shapes of a structure, and the structure has proportional damping. Proposed method can be used to get the equivalent damping ratios of a structure with non-linear control dampers such as friction dampers as well as linear control dampers. To show the effectiveness of the proposed method. we evaluate the equivalent damping ratios of a structure with viscous dampers. AMDs. and friction dampers. The equivalent damping ratios from proposed method are compared to those from eigenvalue analysis for linear control dampers. and those from time history analysis for non-linear control dampers. respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.6
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• pp.951-955
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• 1999

The effects of restricting feed [60% of ad libitum (AL) intake] (FR) or water provided from 0900 h to 1600 h, daily) (WR) or both (FWR) from 14 to 42 days of age on heterophil/lymphocyte (H/L) response and performance in broiler chickens under the hot humid tropical conditions were determined. Feed and/or water limitation retarded growth, but had no adverse effect on overall feed conversion ratio and survivability. The trend for total feed and water consumption was similar to body weight pattern with AL>WR>FR>FWR. The nutritional regimens had significant effect on overall water:feed ratios with FR>(AL=WR)>FWR. Restriction of feed and/or water resulted in marked elevation of H/L ratios. As measured by H/L ratios, the effect of adapting to FR dissipated between 16 to 21 days after the onset of feed restriction. The H/L ratios of WR and FWR birds remained elevated throughout the duration of the experiment.

• Nuclear Engineering and Technology
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• v.46 no.5
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• pp.605-618
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• 2014

The effects of variability of the mechanical properties of lead rubber bearings on the response of a seismic isolation system are investigated. Material variability in manufacturing, aging, and operation temperature is assumed, and two variation models of an isolation system are considered. To evaluate the effect of ground motion characteristics on the response, 27 earthquake record sets with different peak A/V ratios were selected, and three components of ground motions were used for a seismic response analysis. The response in an isolation system and a superstructure increases significantly for ground motions with low A/V ratios. The variation in the mechanical properties of isolators results in a significant influence on the shear strains of the isolators and the acceleration response of the superstructure. The variation provisions in the ASCE-4 are reasonable, but more strict variation limits should be given to isolation systems subjected to ground motions having low A/V ratios. For application of seismic isolation systems to safety-related nuclear structures, the variation in the material and mechanical properties of the isolation system should be properly controlled during the manufacturing and aging processes. In addition, special consideration should be given to minimize the accidental torsion caused by the dissimilarity in the stiffness variations of the isolators.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.10
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• pp.870-879
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• 2005

This paper presents that a transient response can be characterized by certain parameters which are correlated to characteristic polynomial coefficients. These are characteristic ratios and characteristic pulsatances by P. Naslin [4]. We have developed an approach to control directly the transient response. Firstly, speed of the response can be controlled by reconstruction form via multipliable characteristic pulsatances. Secondly, overshoot is controlled by reconstruction form via multipliable characteristic ratios. These formulas can be independently characterized by the system overshoot and the response time to a step input.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.238-246
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• 2003

By using simulated ground motions, which is sum of earthquake signals and noise, we measured the distortion of response spectra due to noise. We found that the distortion is more closely related to the signal-to-noise (S/N) ratio of root-mean-square (RMS) measurement than that of conventional peak measurement. Given a S/M ratio, the distortion of absolute acceleration response spectra is independent on the earthquake magnitude, while that of relative displacement response spectra has a strong dependence on the earthquake magnitude. This means that, when we calculate response spectra from time histories, we can efficiently predict the distortion of acceleration response spectra simply by measuring the RMS SJN ratios, or the distortion of displacement response spectra by combining the RMS S/N ratios and the earthquake magnitudes.

• Earthquakes and Structures
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• v.7 no.4
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• pp.415-448
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• 2014

A method is presented in this paper to analyze the dynamic response behavior of suspended building structures. The effect of semi-rigid connections that link suspended floors with their supporting structure on structural performance is investigated. The connections, like the restrains in non-structural suspended components, are designed as semi-rigid to avoid pounding and as energy dissipation components to reduce structural response. Parametric study is conducted to assess the dynamic characteristics of suspended building structures with varying connection stiffness and suspended mass ratios. Modal analysis is applied to identify the two distinct sets of vibration modes, pendulum and bearing, of a suspended building structure. The cumulative modal mass is discussed to ensure the accuracy in applying the method of response spectrum analysis by SRSS or CQC modal combination. Case studies indicate that a suspended building having semi-rigid connections and proper suspended mass ratios can avoid local pounding failure and reduce seismic response.