• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.1
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• pp.148-155
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• 2001

A disassembility assessment has mostly depend on the subjective decision making from the qualitative element. The work of disassembly is already classified with given disassemble points from the symbolic chart method. It is not useful in the practical assessment because it is not specified. The new method of design for disassembility assessment(DFDA) is practical to introduce the fuzzy number as the conversion of quantitative element from qualitative. It is appled to air-cleaner of passenger-vehicle for the usefulness.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.39-42
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• 2012

Pusher-Loaded Scrapers are important construction equipment for large earthmoving operations. Production rates of a Pusher-Loaded Scraper vary greatly in accordance with the temperature or elevation, the equipment performance, haul speed, haul-road conditions, the method of loading, and Number of scrapers per one pusher. Determining of most economical scrapers fleet regarding the size of equipment, model name, and number of scrapers demands time-consuming calculation because it needs to reference of varied performance charts or tables and repeat complicated calculation. In this study, decision-making support system for the Optimal Pusher-loaded Scrapers Fleet is suggested for the purpose of calculating easily and handling effectively variables which are changed depend of the work conditions. The prototype of this program is developed using MATLAB. And the Database of Pusher-loaded Scraper embodies Performance chart & Retarder chart, soil properties, and calculation-support table.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.428-433
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• 2000

A disassembility assessment has mostly depend on the subjective decision making from the qualitative element. The work of disassembly is already classified with given disassemble points from the symbolic chart method. It is not useful in the practical assessment because it is not specified. The new method of design for disassembility assessment(DFDA) is practical to introduce the fuzzy number as the conversion of quantitative element from qualitative. It is appled to compare the usefulness of air-cleaner in Korea-Japan passenger-vehicle.

• Journal of the Korean Society of Visualization
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• v.4 no.2
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• pp.76-80
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• 2006

The data for friction factor of the pipe correlated by Reynolds number and relative roughness have been reported well as a Moody chart. However, the results for corrugated shapes have been not investigated sufficiently. In this research, therefore, the pressure drop and friction factor are obtained. Flexible metal tubes with corrugations for the measurement are made of stainless steel plates. The kinds of tubes for the measurement are 5 annular types and helical types. The pressure drop & the velocity of the flow are obtained by micromanometer & digital pressure sensor, supplying dry air at several steps. Then the pressure drop is calculated for each tube, using the obtained data. The result shows that the pressure drop is strongly influenced by the viscous dissipation of kinetic energy due to the circulation of flows, rather than a viscous friction loss. The pressure drop increased consistently as the Reynolds number increases.

• Journal of Korean Institute of Industrial Engineers
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• v.25 no.4
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• pp.448-458
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• 1999

This paper proposes sequential control charts with an upper bound on sample size. Existing sequential control charts have no restriction on the number of observations at a sampling point. For situations where sampling and testing an item is time-consuming or expensive, sequential control charts may not be directly applied. When the number of observations in a sampling point reaches the upper bound and there is no out-of-control signal, the proposed cumulative sequential control chart defers the decision to the next sampling point of which starting value is the value of the current statistic. Two Markov chains, inner and outer chains, are used to derive the formulas for evaluating the performance of the proposed chart. It is compared with $\bar{X}$ and cumulative sum control charts with fixed and variable sample sizes. The fast initial response (FIR) feature is studied. Guidelines for the design of the proposed charts are also given.

• Journal of the Korean GEO-environmental Society
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• v.18 no.3
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• pp.31-38
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• 2017

The purpose of this study is to propose a chart that can easily estimate the seismic failure probability of small and medium sized earthfill dams with little geotechnical information. By considering the existing method and procedure for estimating the seismic failure probability of a dam, the zero seismic failure probability curve, on which the seismic probability is zero regardless of the geotechnical properties of the dam, was determined in the form of hyperbola in the dam height and freeboard ratio plane. It was confirmed that the dam height-freeboard ratio distribution pattern of the Korean small and medium sized dams was shaped like a hyperbola like the zero seismic failure probability curve. Therefore, a estimation chart was constructed in which a number of seismic failure probability contours are represented by a number of hyperbolas at regular intervals in the dam height-freeboard ratio plane. The proposed chart was applied to the calculation of the seismic failure probability of two small and midium sized dams with relatively well-managed geotechnical properties and the validity of the chart was confirmed by comparison with the results obtained by the existing procedures and methods. In the future, the proposed chart is expected to be useful in considering investment priorities for maintenance and reinforcement of small and medium sized dams in preparation for earthquakes.

• Journal of the Korean Society of Safety
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• v.31 no.4
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• pp.35-41
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• 2016

In order to guarantee the process safety and prevent accidents, the deviations from normal operating conditions should be monitored and their root causes have to be identified as soon as possible. The statistical theories-based method among various fault diagnosis methods has been gaining popularity, due to simplicity and quickness. However, according to fault magnitudes, the scalar value generated by statistical methods can be changed and this point can lead to produce wrong information. To solve this difficulty, this work employs PCA (Principal Component Analysis) based method with qualitative information. In the case study of our previous study, the number of assumed faults is much smaller than that of process variables. In the case study of this study, the number of predefined faults is 19, while that of process variables is 6. It means that a fault diagnosis becomes more difficult and it is really hard to isolate a single fault with a small number of variables. The PCA model is constructed under normal operation data in order to get a loading vector and the data set of assumed faulty conditions is applied with PCA model. The significant changes on PC (Principal Components) axes are monitored with CUSUM (Cumulative Sum Control Chart) and recorded to make the information, which can be used to identify the types of fault.

• The Korean Journal of Applied Statistics
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• v.37 no.1
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• pp.73-86
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• 2024

A radial chart of Excel is very useful graphical method in delivering information for numerical data. However, it is not easy to discriminate or classify many individuals. In this case, after shaping each individual of a radial chart, we need to apply shape analysis. For a radial chart, since landmarks for shaping are formed as many as the number of variables representing the characteristics of the object, we consider a shape that connects them to a line. If the shape becomes complicated due to the large number of variables, it is difficult to easily grasp even if visualized using a radial chart. Principal component analysis (PCA) is performed on variables to create a visually effective shape. The classification table and classification rate are checked by applying the techniques of traditional discriminant analysis, support vector machine (SVM), and artificial neural network (ANN), before and after principal component analysis. In addition, the difference in discrimination between the two coordinates of generalized procrustes analysis (GPA) coordinates and Bookstein coordinates is compared. Bookstein coordinates are obtained by converting the position, rotation, and scale of the shape around the base landmarks, and show higher rate than GPA coordinates for the classification rate.

• Industrial Engineering and Management Systems
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• v.6 no.1
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• pp.11-21
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• 2007

The PDCA (Plan, Do, Check and Act) cycle is often used in the field of quality management. Recently, business environments have become more competitive, and the due time of products has shortened. In a short production run process, to increase efficiency of management, the necessity for distinguishing the PDCA design that starts with PLAN and the CAPD design that starts with CHECK has been clarified. Starting from Duncan (1956), there have been a number of papers dealing with the economic design of control charts from the viewpoint of production run. Some authors (Gibra, 1971; Ladany and Bedi, 1976; etc.) have studied the economic design for finite-length runs; other authors (Crowder, 1992; Del Castillo and Montgomery, 1996; etc.) have studied the economic design for short runs. However, neither the PDCA nor the CAPD design of control charts has been considered. In this paper, both the PDCA and CAPD designs of the $\bar{\x}$ chart are defined based on Del Castillo and Montgomery's design (1996), and their mathematical formulations are shown. Then from an economic viewpoint, the optimal values of the sample size per each sampling, control limits width, and the sampling interval of the two designs are studied. Finally, by numerically analyzing the relations between the key parameters and the total expected cost per unit time, the comparisons between the two designs are considered in detail.

• Journal of Korean Library and Information Science Society
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• v.15
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• pp.207-243
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• 1988

This study is an attempt to furnish some helpful data for the maximum use of online information retrieval systems based on the comparative analysis of commands and operating terms employed by DIALOG, ORBIT and BRS which are three largest information retrieval systems in the world. To begin with, the historical development, service contents and retrieval functions of three systems were overviewed in the second chapter, on the basis of which the concrete functions and contents of the commands and the operating terms of the three systems were compared and analyzed one another. Commands were explained divided into basic and special ones. The basic commands subdivided into 44 items were put into the form of a diagram(Table 1). The special commands were first subdivided into search commnad, output-related commands and su n.0, pplementary commands, and then 14 items of which were comparatively analyzed and were represented as a chart(Table 2). In addition, any stand-alone commands employed by each system were also analyzed as a chart(Table 3). The Operating terms other than commands were subdivided into 16 items and were represented as a chart(Table 4). Password, inverted file, search step number in search session, etc were explained to the very detailed extent. A self-evident, single word is that the through understanding of commands is essential to the maximm use of all the functions of each of three systems.