• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.909-912
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• 2006

This paper examined the applicability of convex hull, which is defined as the minimal convex polygon including all points, to assessment model for effective region. In order to validate the applicability of the convex hull to assessment model for effective region, a genetic algorithm was adopted as a optimum technique, and an artificial neural network was adopted as a prediction model for material properties. The mix-proportion obtained from the proposed technique is more reasonable than that obtained from previous work.

• IE interfaces
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• v.14 no.1
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• pp.106-110
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• 2001

The importance of development of occupational safety index is truly great. It will contribute to the wise direction of safety program. In present, frequency and severity ratios were the standard measure. These terms express the incidence of major injuries and severity of the major injuries experience, each with relation to the employee-hours of work exposure during the period that is measured. But these measure don't expressed the dangerous feeling degree of worker. In this study, Effective Industrial Safety Index(EISI) was developed using dangerous feeling degree of worker, frequency of injuries, and severity of injury. EISI can be used as an aid for effective safety management in workplace.

• International Journal of Computer Science & Network Security
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• v.21 no.8
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• pp.212-218
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• 2021

The Proportional Integral Derivative (PID) controller is the most popular industrial controller and more than 90% process industries use this controller. During the past 50 years, numerous good tuning methods have been proposed for Single Input Single Output Systems. However, design of PI/PID controllers for multivariable processes is a challenge for the researchers. A comparative study of three PID controllers design methods has been carried-out. These methods include the DS (Direct Synthesis) method, IMC (Internal model Control) method and ETF (Effective Transfer Function) method. MIMO PID controllers are designed for a number of 2×2, 3×3 and 4×4 process models with multiple delays. The performance of the three methods has been evaluated through simulation studies in Matlab/Simulink environment. After extensive simulation studies, it is found that the Effective Transfer Function (ETF) Method produces better output responses among two methods. In this work, only decentralized methods of PID controllers have been studied and investigated.

• Smart Structures and Systems
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• v.24 no.2
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• pp.193-207
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• 2019

This study concerns with morphing structures, e.g. as applied in the aerospace industry. A morphing aerofoil structure capable of variable geometry was developed, which was shown to be able to cater for the different aerodynamic requirements at different stages of flight. In this work, the useful and relatively simple method has been applied, which provides a direct method for calculating required morphing shape displacements via finding the most effective bar through calculating bar sensitivity to displacement and calculating set of length actuations for bar assembly to control/adjust shape imperfection of prestressable structural assemblies including complex elements ("macro-elements", e.g., the pantographic element), involving Matrix Condensation. The technique has been verified by experiments on the physical model of an aerofoil shaped morphing pantographic structure. Overall, experimental results agree well with theoretical prediction. Furthermore, the technique of multi-iteration adjustment was presented that effective in eliminating errors that occur in the practical adjustment process itself. It has been demonstrated by the experiments on the physical model of pantographic morphing structure. Finally, the study discusses identification of the most effective bars with the objective of minimal number of actuators or minimum actuation.

• International Journal of Computer Science & Network Security
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• v.21 no.9
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• pp.11-18
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• 2021

The Proportional Integral Derivative (PID) controller is the most popular industrial controller and more than 90% process industries use this controller. During the past 50 years, numerous good tuning methods have been proposed for Single Input Single Output Systems. However, design of PI/PID controllers for multivariable processes is a challenge for the researchers. A comparative study of three PID controllers design methods has been carried-out. These methods include the DS (Direct Synthesis) method, IMC (Internal model Control) method and ETF (Effective Transfer Function) method. MIMO PID controllers are designed for a number of 2×2, 3×3 and 4×4 process models with multiple delays. The performance of the three methods has been evaluated through simulation studies in Matlab/Simulink environment. After extensive simulation studies, it is found that the Effective Transfer Function (ETF) Method produces better output responses among two methods. In this work, only decentralized methods of PID controllers have been studied and investigated.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.811-816
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• 2022

This work presents the methodology used to expand the capabilities of the Monte Carlo code OpenMC for the calculation of reactor kinetic parameters: effective delayed neutron fraction β_eff and neutron generation time L. The modified code, OpenMC(Time-Dependent) or OpenMC(TD), was then used to calculate the effective delayed neutron fraction by using the prompt method, while the neutron generation time was estimated using the pulsed method, fitting Λ to the decay of the neutron population. OpenMC(TD) is intended to serve as an alternative for the estimation of kinetic parameters when licensed codes are not available. The results obtained are compared to experimental data and MCNP calculated values for 18 benchmark configurations.

• Geomechanics and Engineering
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• v.29 no.5
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• pp.583-598
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• 2022

The Compaction effect is important for evaluating the subgrade construction. However, there is little research exploring the compaction quality of deep soil using hydraulic compaction. According to reinforcement effect analysis, dimensional analysis is adopted in this work to analyze subgrade compactness within the effective reinforcement depth, and a prediction model is obtained. A hydraulic compactor is then employed to carry out an in-situ reinforcement test on gravel soil subgrade, and the subgrade parameters before and after reinforcement are analyzed. Results show that a reinforcement difference exists inside the subgrade, and the effective reinforcement depth is defined as increasing compactness to 90% in the depth direction. Layered compactness within the effective reinforcement depth is expressed by parameters including the drop distance of the rammer, peak acceleration, tamping times, subgrade settlement, and properties of rammer and filler. Finally, a field test is conducted to verify the results.

• Journal of the Korean Chemical Society
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• v.60 no.5
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• pp.327-341
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• 2016

This study explores the effective visual resources in the “regularity in chemical reactions” unit of ninth grade science textbooks (2009 revised version). The frequency and role of visual resources were initially examined, and the students’ perceptions of visual resources were investigated. The results of the analysis represented the learning material presentation (68%), motivational categories (14%), guide to inquiry procedures (9%), and inquiry results and summaries (8%). According to the investigation of the students’ perceptions of visual resources, the most effective visual resource for motivation is a photograph depicting physical and chemical changes, such as in bread baking and the most effective for learning material presentations in mass conservation, definite proportion, and stoichiometric concept units were a cartoon, graph, and formula representing stoichiometric phenomena, respectively. The most effective resource for guide to inquiry (experimental) procedures were photographs of both instruments and sequential experiment processes; and in the inquiry results and summary category, incomplete tables and graphs for students to work on themselves. The aims of this research are to increase the usefulness of visual resources in the teaching-learning activity and provide informative supplements for the development and improvement of visual resources, according to the students’ perceptions.

• Nuclear Engineering and Technology
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• v.49 no.7
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• pp.1571-1574
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• 2017

In the present work, the gamma ray backscattering technique was used to determine the effective atomic numbers for certain binary alloys. With the help of a muffle furnace, the binary alloys were synthesized using the melt quenching technique with different compositions of $_{82}Pb$, $_{50}Sn$, and $_{30}Zn$. The intensity distribution of backscattered photons from radioactive isotope $^{22}Na$ (511 keV) was recorded with the help of GAMMARAD5 [$76mm{\times}76mm$ NaI(Tl) scintillator detector] and analyzed as a function of both atomic number and thickness of the target material. The effective atomic numbers for the same binary alloys were also computed theoretically using the atomic to electronic cross-section method with the help of the mass attenuation coefficient database of WinXCom (2001). Good agreement was observed between theoretical and experimental results for the effective atomic numbers of all the selected alloys.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.2
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• pp.25-31
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• 2004

Machinability in metal cutting processes depends on cutting input conditions such as cutting velocity, feed rate, depth of cut, types of work material and tool shape factors. In this study, to assess chip breaking characteristics of a turning process, an equivalent oblique cutting system to this has been established. And the equivalent effective rake angle was determined using side rake angle, back rake angle and side cutting edge angle of the tool. A non-dimensional parameter, Chip breaking index(CB), was used to assess Chip breaking characteristics of chip in conjunction with the equivalent effective rake angle. In case of positive rake angles of the equivalent effective rake, the back rake angle has little effect on the chip breaking characteristics however, in case of negative ones, the side rake angle has some effect on Chip breaking characteristics.