• 한국콘텐츠학회논문지
• /
• 제18권10호
• /
• pp.361-367
• /
• 2018

이 연구의 목적은 불화 수소산 에칭 처리가 안정화된 정방 정계 지르코니아 다결정 (Y-TZP)의 결합 강도에 미치는 영향을 평가하는 것이었다. 4 그룹의 지르코니아 - 수지 시멘트 시편을 준비 하였다. 1) ZGS 그룹 (zirconia, no treatment) 2) ZGSH 그룹 (zirconia, hydrofluoric acid etching treatment) 3) H-ZGS 그룹 (Hybrid zirconia, no treatment) 4) H-ZGSH 그룹 (Hybrid zirconia, hydrofluoric acid etching treatment). 지르코니아와 도재 사이의 전단 결합 강도는 Instron Universal Testing Machine (ModelBBP-500, Instron Corporation, Kyunggi, Korea)을 사용하여 측정 하였다. 독립표본 t-test와 two-way ANOVA (${\alpha}=0.05$)를 사용하여 데이터를 통계적으로 분석했다. 세라믹 - 수지 시멘트 결합강도는 불화 수소산 에칭 처리에 영향을 받았다 (p <0.05). 파단 표면의 디지털 현미경 검사는 불화 수소산 에칭 처리한 표면처리 된 지르코니아 및 하이브리드 지르코니아 그룹에서 접착성 및 응집성 파절이 동시에 발생하는 결함을 보였다.

• Smart Structures and Systems
• /
• 제25권6호
• /
• pp.765-778
• /
• 2020

The present study intends to find a proper solution for the estimation of the physical behaviors of enlarged piles through a combination of small-scale laboratory tests and a hybrid computational predictive intelligence process. In the first step, experimental program is completed considering various critical influential factors. The results of the best multilayer perceptron (MLP)-based predictive network was implemented through three mathematical-based solutions of dragonfly algorithm (DA), whale optimization algorithm (WOA), and ant lion optimization (ALO). Three proposed models, after convergence analysis, suggested excellent performance. These analyses varied based on neurons number (e.g., in the basis MLP hidden layer) and of course, the level of its complexity. The training R² results of the best hybrid structure of DA-MLP, WOA-MLP, and ALO-MLP were 0.996, 0.996, and 0.998 where the testing R² was 0.995, 0.985, and 0.998, respectively. Similarly, the training RMSE of 0.046, 0.051, and 0.034 were obtained for the training and testing datasets of DA-MLP, WOA-MLP, and ALO-MLP techniques, while the testing RMSE of 0.088, 0.053, and 0.053, respectively. This obtained result demonstrates the excellent prediction from the optimized structure of the proposed models if only population sensitivity analysis performs. Indeed, the ALO-MLP was slightly better than WOA-MLP and DA-MLP methods.

• Structural Engineering and Mechanics
• /
• 제5권4호
• /
• pp.339-353
• /
• 1997

Fiber reinforced plastic (FRP) rods provide certain benefits over steel as concrete reinforcement, such as corrosion resistance, magnetic and electrical insulation, light weight, and high strength. FRP composites can be combined with a steel core to form hybrid reinforcing rods that take advantage of properties of both materials. The objective of this study was to characterize the bond behavior of hybrid FRP rods made with braided epoxy-impregnated aramid or poly-vinyl alcohol FRP skins. Eleven rod types were tested using two concrete strengths. Specific topics examined were bond strength, slip, and type of failure in concentric pull-out tests from concrete cubes. From analysis of identical pull-out tests on both hybrid and steel rods, information on relative bond strength and behavior were obtained. It is concluded that strength is similar but slip in hybrid rods is much higher. Hybrid rods failed either by pull-out or splitting the concrete block (with or without yielding of the steel core). Experimental data showed consistency with similar test results presented in the literature.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제14권2호
• /
• pp.93-97
• /
• 2007

A Silkworm breeding programme was designed to develop a robust but productive bivoltine silkworm hybrid of Bombyx mori L. suitable for rearing throughout the year in tropical climate by utilizing indigenous polyvoltine and productive bivoltine breeds. The breeding was carried out under high temperature ($36^{\circ}C{\pm}1^{\circ}C$) and low humidity ($50{\pm}5%$) conditions in the environmental chamber. By $F_{12}$, three oval and three dumbbell breeds were isolated with higher survival and productive merits. These breeds were utilized in the hybrid evaluation along with other popular breeds. Based on combining ability test results, the hybrid $SR_2{\times}SR_5$ was selected for large scale testing and evaluated in different seasons. The evaluation studies indicated that the hybrid has higher viability and productive merits and it is suitable to rear throughout the year. The hybrid $SR_2{\times}SR_5$ recorded a survival of 92.0%, cocoon shell weight of 0.417 g, cocoon shell percentage of 23.0 and a filament length of 1042 meters under hot and dry conditions of environmental chamber compared to the control thermo-tolerant hybrid $CSR18{\times}CSR19$.

• Earthquakes and Structures
• /
• 제8권6호
• /
• pp.1325-1348
• /
• 2015

Real-time hybrid testing (RTHT) involves virtual splitting of the structure into two parts: physical substructure that contains the key region of interest which is tested in a laboratory and numerical substructure that contains the remaining part of the structure in the form of a numerical model. This paper numerically assesses four step-by-step integration methods (Central difference method (CDM), Operator splitting method (OSM), Rosenbrock based method (RBM) and CR-integration method (CR)) which are widely used in RTHT. The methods have been assessed in terms of stability and accuracy for various realistic damping ratios of the physical substructure. The stability is assessed in terms of the spectral radii of the amplification matrix while the accuracy in terms of numerical damping and period distortion. In order to evaluate the performance of the methods, five carefully chosen examples have been studied - undamped SDOF, damped SDOF, instantaneous softening, instantaneous hardening and hysteretic system. The performance of the methods is measured in terms of a non-dimensional error index for displacement and velocity. Based on the error indices, it is observed that OSM and RBM are robust and performs fairly well in all the cases. CDM performed well for undamped SDOF system. CR method can be used for the system showing softening behaviour. The error indices indicate that accuracy of OSM is more than other method in case of hysteretic system. The accuracy of the results obtained through time integration methods for different damping ratios of the physical substructure is addressed in the present study. In the presence of a number of integration methods, it is preferable to have criteria for the selection of the time integration scheme. As such criteria are not available presently, this paper attempts to fill this gap by numerically assessing the four commonly used step-by-step methods.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
• /
• pp.201-204
• /
• 2005

The bond characteristics of two types hybrid FRP (fiber reinforced polymer) reinforcing bars with different rib geometry were analyzed experimentally. Two types of hybrid FRP. reinforcing bars such as spiral and cross type with different relative rib area were considered in this test. All testing procedures including specimens preparation, set-up of test equipments and measuring devices were made according to the recommendations of CSA Standard S806-02. From the test results, it was found' that cross type hybrid FRP reinforcing bars showed the higher bond strength than that of spiral type's due to the higher relative rib area.

• Journal of the Korean Data and Information Science Society
• /
• 제25권2호
• /
• pp.431-438
• /
• 2014

Type I hybrid censoring scheme is the combination of the Type I and Type II censoring scheme introduced by Epstein (1954). Epstein considered a hybrid censoring sampling scheme in which the life testing experiment is terminated at a random time $T^*$ which is the time that happens rst among the following two; time of the kth unit is observed or time of the experiment length set in advance. The likelihood function of this scheme from the Rayleigh distribution cannot be solved in a explicit solution and thus we approximate the function by the Taylor series expansion. In this process, we propose four dierent methods of expansion skill.

• 전기학회논문지P
• /
• 제63권4호
• /
• pp.277-282
• /
• 2014

Hybrid transformer means the distribution transformer, one of multi-function transformer equipped with the enhancement function of harmonics and unbalance. In other words, since existing transformer are equipped simply with transformation function only, a separated electric facility should be additionally installed in order to reduce the mutual harmonics and unbalance. Meanwhile, since hybrid transformer can perform the reduction of harmonics and unbalance as well as transformation function simultaneously through zigzag winding, it doesn't need any additional electric facility. This study addressed the issue of developing and testing the performance of a generator that would reduce the harmonics supplied to the grid when grid-connected with the output of a photovoltaic inverter for photovoltaic generation system.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
• /
• pp.629-632
• /
• 2006

The various rib geometry of hybrid fiber reinforced polymer (FRP) reinforcing bars were analyzed by finite element method. From the analysis result, two types of hybrid FRP reinforcing bars such as spiral and cross type with the same dimension of rib geometry were fabricated in this study. To evaluate the bond properties of them, direct pull-out test was performed. All testing procedures including specimens preparation, set-up of test equipments and measuring devices were made in accordance with the recommendations of CSA Standard S806-02. From the test results, it was found that cross type hybrid FRP reinforcing bars showed the highest bond strength than that of the others due to the higher relative rib area.

• International Journal of Computer Science & Network Security
• /
• 제23권3호
• /
• pp.161-168
• /
• 2023

It is a common practice to use a password in order to restrict access to information, or in a general sense, to assets. Right selection of the password is necessary for protecting the assets more effectively. Password finding/cracking try outs are performed for deciding which level of protection do used or prospective passwords offer, and password cracking algorithms are generated. These algorithms are becoming more intelligent and succeed in finding more number of passwords in less tries and in a shorter duration. In this study, the performances of possible password finding algorithms are measured, and a hybrid algorithm based on the performances of different password cracking algorithms is generated, and it is demonstrated that the performance of the hybrid algorithm is superior to the base algorithms.