• Structural Engineering and Mechanics
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• v.40 no.4
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• pp.541-562
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• 2011

In the design of earthquake resistant reinforced concrete (RC) structures, both flexural strength and deformability need to be considered. However, in almost all existing RC design codes, the design of flexural strength and deformability of RC beams are separated and independent on each other. Therefore, the pros and cons of using high-performance materials on the flexural performance of RC beams are not revealed. From the theoretical results obtained in a previous study on flexural deformability of RC beams, it is seen that the critical design factors such as degree of reinforcement, concrete/steel yield strength and confining pressure would simultaneously affect the flexural strength and deformability. To study the effects of these factors, the previous theoretical results are presented in various charts plotting flexural strength against deformability. Using these charts, a "concurrent flexural strength and deformability design" that would allow structural engineers to consider simultaneously both strength and deformability requirements is developed. For application in real construction practice where concrete strength is usually prescribed, a simpler method of determining the maximum and minimum limits of degree of reinforcement for a particular pair of strength and deformability demand is proposed. Numerical examples are presented to illustrate the application of both design methods.

• Geotechnical Engineering
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• v.14 no.5
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• pp.173-180
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• 1998

This paper presents the design chart to evaluate the two-demensional stability of geoteztilereinforcement embankments on soft foundations. The potential failure surface in this study is assumed as the logarithmic spiral curves refracted at the boundary of layers. To facilitate the iterative calculations, a program that determines the geoteztile tensile force for geotextilereinforcement embankments was developed. This program can be used for situations with a variety of soil layers and soil types. And it can be also used for a static or seismic condition. A series of calculations has been made for a schematised situation. The results of these computation are shown in design charts. Considering static or seismic load strate, these charts in the preliminary stage of the design provide a reasonable estimate of geoteztile tensile force for geotextile-reinforcement embankments on softs foundations. In the final swage a more detailed calculation can be made by developed programs.

• Journal of Korean Society for Quality Management
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• v.37 no.2
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• pp.46-57
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• 2009

The traditional approach to economic design of control charts is based on the assumption that a process is monitored using a performance variable. However, various types of automatic test equipments recently introduced as a part of factory automation usually measure surrogate variables instead of performance variables that are costly to measure. In this article we propose a model for economic design of a control chart which uses a surrogate variable that is highly correlated with the performance variable. The optimum values of the design parameters are determined by maximizing the total average income per cycle time. Numerical studies are performed to compare the proposed $\bar{X}$ control charts with the traditional model using the examples in Panagos et al. (1985).

• Journal of Korean Institute of Industrial Engineers
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• v.6 no.2
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• pp.31-36
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• 1980

This paper proposes a very simple algorithm for determining the parameters in the economic design of s-charts. These parameters are the sample size, the factor determining the spread of the control limit and the sampling interval. Several examples show that the parameters determined by this algorithm are very close to the exact optimal values.

• The Korean Journal of Applied Statistics
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• v.22 no.6
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• pp.1131-1142
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• 2009

We suggest a fast and accurate algorithm to compute ARLs of CUSUM chart for controling process variance. The algorithm solves the characteristic integral equations of CUSUM chart (for controling variance). The algorithm is directly applicable for the cases of odd sample sizes. When the sample size is even, by using well-known approximation algorithm combinedly with the new algorithm for neighboring odd sample sizes, we can also evaluate the ARLs of CUSUM charts efficiently and accurately. Based on the new algorithm we consider the optimal design of upward and downward CUSUM charts for controling process variance.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.2
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• pp.195-203
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• 2008

This study collected the latest 30-year (1976~2005) continuous rainfall data hourly recorded at 61 meterological observatories in Korea. The continuous rainfall data was divided into individual rainfall events. In addition, distribution charts of average intervent times between adjacent rainfall events were created to facilitate the application to the overflow risk-based design of storm-water infiltration basin. This study shows that the one-parameter exponential distribution is suitable for the frequency distribution of the average intervent times for the domestic rainfall data. Distribution charts of the average intervent times were created for 4 hour and 6 hour of storm separation time, respectively. The inland Gyeongsangbuk-do and Western coastal area had relatively longer average intervent times, whereas Southern coastal area and Jeju-do had relatively shorter average intervent times.

• Journal of Ocean Engineering and Technology
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• v.21 no.5
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• pp.9-17
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• 2007

This paper deals with the design and analysis of a 250kW class impulse turbine for wave energy conversion. Numerical analysis was performed using FLUENT. The size and the performance of a turbine required to provide a certain power can be estimated using a series of performance charts built through the present study. Temporal and spatial variations of flaw fields were also considered and compared with those of uniform inflow. It was concluded that a simple steady-flow analysis using performance charts still provided a practical and useful way to predict the design and performance of turbines.

• International Journal of Quality Innovation
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• v.1 no.1
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• pp.16-23
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• 2000

• Journal of the Korean Society of Safety
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• v.13 no.4
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• pp.142-154
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• 1998

A stirling engine is a mechanism used to convert heat to power and operates on a closed regenerative thermodynamic cycle with compression and expansion of the working fluid at different temperature. The performance of a stilting cycle machine is a function of six independent parameters, namely; (1) speed N(r.p.m), (2) pressure of the working fluid p(Pa), (3) ratio of the temperature in the compression and expansion space ${\tau}(=T_C/T_E)$ , (4) ratio of the swept volumes in these two spaces K, (5) phase angle $\alpha$ and (6) dead volume ratio X. This paper describes the procedure and presents the results of computations carried out to establish the optimum combinations of these six parameters for maximum engine output for the machine acting as a prime mover, over a combined temperature range from $300^{\circ}K$ to $1000^{\circ}K$ and dead volume ratio X ranging from 0.1 to 2.0. The output of a stilting cycle machine can be expressed in terms of nondimensional power in several different ways. Four methods were studied in detail, the parameters optimized and design charts and engine power charts prepared. The results of this paper may be useful as a guide to the likely effects on the performance of some of the important design parameters and regenerator design.

• Computers and Concrete
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• v.22 no.6
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• pp.573-592
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• 2018

An analytical methodology for the calculation of the flexural and the shear capacity of concrete members with Fibre-Reinforced-Polymer (FRP) bars as tensional reinforcement is proposed. The flexural analysis is initially based on the design provisions of ACI 440.1R-15 which have properly been modified to develop general charts that simplify computations and provide hand calculations. The specially developed charts include non-dimensional variables and can easily be applied in sections with various geometrical properties, concrete grade and FRP properties. The proposed shear model combines three theoretical considerations to facilitate calculations. A unified flexural/shear approach is developed in flow chart which can be used to estimate the ultimate strength and the expected failure mode of a concrete beam reinforced with longitudinal FRP bars, with or without transverse reinforcement. The proposed methodology is verified using existing experimental data of 138 beams from the literature, and it predicts the load-bearing capacity and the failure mode with satisfactory accuracy.