• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.16 no.1
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• pp.117-124
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• 2020

3D printing is a technology that has significantly grown in recent years, particularly in the aerospace, defense, and medical sectors where it offers significant potential cost savings and reduction of the supply chain by allowing parts to be manufactured on-site rather than at a distance supplier. In nuclear industry, 3D printing technology should be applied according to the manufacturing trend change. For the application of 3D printing technology to the nuclear power plant, several problems, including the absence of code & standards of materials, processes and testing & inspection methods etc, should be solved. Preemptively, the improvement of reliability of 3D printing technology, including mechanical properties, structural performance, service performance and aging degradation of 3D printed parts should be supported. These results can be achieved by collaboration of many organizations such as institute, 3D printer manufacturer, metal powder supplier, nuclear part manufacturer, standard developing organization, and nuclear utility.

• Journal of the Korean Operations Research and Management Science Society
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• v.12 no.2
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• pp.21-35
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• 1987

This paper presents a method for propagating fuzzy concepts through fuzzy IF-THEN-ELSE rules. A fuzzy IF-THEN-ELSE rule consists of a set of fuzzy condition and conclusion pairs. These pairs assumed to contain informations about a fuzzy mapping from fuzzy concepts of condition parts to the fuzzy concepts of conclusion parts. Conventionally, vectors are used to define fuzzy concepts and matrices are used to define a fuzzy mapping between fuzzy conditions and conclusions. This approach, however, does not satisfy the existing condition property, i.e., when a fuzzy input data exactly matches to a fuzzy condition, fuzzy output data should be mapped to a corresponding fuzzy conclusion. Alternatively, we propose a parameterized approach in which every fuzzy concept is described by a parameterized standard function, including fuzzy conditions and fuzzy conclusions. A fuzzy IF-THEN-ELSE rule takes the parameterized fuzzy concept as an input, and produces a standard function with new parameters as an output. New parameters are determined by a parameterwise interpolation. That is, each output parameters are determined by interpolating parameters of the same class contained in fuzzy conclusions. Obviously, the proposed scheme always satisfies the existing condition property.

• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.94-98
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• 2012

In order to serve the exact torque clamping force, the torque measurement system use the curve fitting algorithm by the least square. The corrected least square curve fitting algorithm which suggested in this paper can surpport more exact clamping force for fastner in variable industry field using the torque. At first, This paper introduces mathematical modeling for curve fitting algorithm, and simulate it. As a result, the corrected least square algorithm have shown lower standard error value than that of the used algoritm with torque, and so this corrected least square algorithm prove high accuracy than nomal least square algorithm. The suggested algorithm will contribute to improvement of cost and safety on industry field with bolt clamping force for precision industry parts, electronics parts, aircraft, aerospace, etc.

• Steel and Composite Structures
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• v.20 no.2
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• pp.251-266
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• 2016

The paper combines two distinct parts. First the behavior of welded headed studs with small diameters of 10 and 13 mm acting as shear connectors (which are not embraced in current standards) is studied. Based on standard push tests the load-slip relationships and strengths are evaluated. While the current standard (Eurocode 4 and AISC) formulas used for such studs give reasonable but too conservative strengths, less conservative and full load-slip rigidities are evaluated and recommended for a subsequent investigation or design. In the second part of the paper the partially encased beams under bending are analyzed. Following former experiments showing rather indistinct role of studs used for shear connection in such beams their role is studied. Numerical model employing ANSYS software is presented and validated using former experimental data. Subsequent parametric studies investigate the longitudinal shear between steel and concrete parts of the beams with respect to friction at the steel and concrete interface and contribution of studs with small diameters required predominantly for assembly stages (concreting). Substantial influence of the friction and effect of concrete confinement was observed with rather less noticeable contribution of the studs. Distribution of the longitudinal shear and its sharing between friction and studs is presented with concluding remarks.

• Design & Manufacturing
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• v.15 no.4
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• pp.1-7
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• 2021

A study on in-mold punching technology for hole piercing during molding of hollow plastic parts was conducted. Considering the non-linearity of the HDPE plastic material, mechanical properties were obtained according to the change in temperature and load speed. A standard specimen for the in-mold punching test was designed to implement the in-mold punching process, and the specimen was obtained through injection molding. In order to analyze the influence of process variables during in-mold punching, an in-mold punching mold capable of controlling variables such as temperature and support pressure of the specimen was designed and manufactured. Mold heating characteristics were confirmed through finite element analysis, and punching simulations for changes in process conditions were performed to analyze punching characteristics and reflected in the experiment. Through simulations and experiments, it was found that the heating temperature, punch shape, punching speed, and pressure of the back side of the specimen were very important during in-mold punching of HDPE materials, and optimal conditions were acquired within a given range.

• Journal of the Korean Society of Costume
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• v.19
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• pp.105-125
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• 1992

The research, aiming an automatic pattern design of Korean Costume by utilizing CAD system, tried Grading, Seaming and Marking with a theme of girl's color-strip blouse & skirt. The content & conclusion of the research can be outlined as follows; 1) As we reviewed the current situation of Korean costume which becomes more likely celebrational or festival costume, while the demand of it is getting increase, it's being dealt mostly as ready-made dresses with different qualities & designs. Especially childrens ready-made ones were highly demanded to be picked up as the theme. 2) For the original drawing of children's color-strip blouse & skirt, Kyung-Ja Park's drawing method was used here, and for the substitute of particular body parts absolute size, Joo-Won Lee's standard size chart from a size-study by ages. 3) To work with CAD system we had input master pattern, drawn for age 5 as basic size, then graded six step-sizes for 1-11 years old. For add-subtract of particular body parts size, we graded through computing the standard variation among items to get the pattern developed into ready-made standard size, we can make precise plotting by grading wanted size very rapidly if we correct the rule of changed items different from standard size to make utilization possible enough with easy order method of ready-made Korean Dress. 4) We produced Marker after attaching a margin to seam accordingly by parts for each pattern using P/D/S to mark, In mass gament-cutting, the loss of time and material can minimized. In this research the apparel CAD system which has been utilized and only be western fashion industry was introduced for the design of ready-made Korean costume and utilized it in Grading, Marking which are critical steps to improve productivity and have reported the result in the research. Thus we expect that less cost, improved productivity and better quality with minimized loss of material from marking as well as from prompt and precise size-drawing. Furthermore the utilization of CAD system is considered as an effective one in terms of the research & the development to remove effective one in terms of the research & the development to remove irrational elements in the design and production process of Korean costume as well as in terms of the study of Korean Costume development through creative works of Korean Costume.

• International Journal of Precision Engineering and Manufacturing
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• v.2 no.3
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• pp.69-78
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• 2001

This paper presents a process and operation planning system and an NC code post-processor for effective machining of press dies for production of cars. Based on the machining feature, major parts of press dies are categorized into 15 groups and a standard process plan is defined for each group. The standard process plan consists of a series of processes where a process is defined as a group of operations that can be done with one setup. Details such as cutting tools, cutting conditions, and tool paths are decided at the operation planning stage. At the final stage of process and operation planning, the NC code post-processor adjusts feedrates along the tool path to reduce machining time while maintaining the quality. The adjustment rule is selected based on the machining load estimated by virtual machining.

• Journal of Power System Engineering
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• v.15 no.4
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• pp.54-59
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• 2011

Currently, plastic gear is widely used as parts of office equipment and industrial machines, because plastic substance has an advantage of light weight and possible to operate in oil-fewer conditions. However, under cyclic loadings, their occurred repetitive deformation due to weak tensile strength and bending stress rather than metal gear. Furthermore, they have a problem of attrition and breakage owing to frictional heat. For solving these problems, when plastic gear's opponents are metal gear, we should design that plastic gear's tooth be thick and metal gear's tooth be thin. In this research, we developed the program which developing tooth profile of non-standard gears automatically and calculating over-pin diameter for inspection after making gear.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.10
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• pp.80-88
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• 1997

This paper describes a design of a Wavelet Adaptive Filter(WAF) for the removal of the baseline wandering and the minimization of the signal distortion using by wavelet transform and adaptive filter in the ECG signal. WAF consists of two parts. The first part is wavelet transform that decomposes the ECG signal into seven frequency bands using Vaidyanathan and Hoang wavelet. The second part is adaptive filter that uses the signal of seventh low frequency band among the wavelet transformed signals as primary input and a unit impulse sequence as reference input. For the evaluation of the performance of WAF, we used several baseline wandering elimination filters such as commerical standard filter with cutoff frequency of 0.5Hz and general adaptive filter. We made use of MIT/BIH database and real patient data for the evaluation. In conclusion, WAF showed a lower ST segement distortion than standard filter and adaptive filter and has a higher eliminated noise power than standard filter and adaptive filter.

• Journal of Auto-vehicle Safety Association
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• v.12 no.3
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• pp.27-33
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• 2020

In this paper, the process of predicting efficient durability performance for vibration durability test of automobile parts using vibration test load on automobile fuel tank is presented. First of all, the common standard load that can be applied to the initial development process of the automobile was used for the fuel tank and the vulnerability of the fuel tank to the vibration fatigue load was identified through frequency response analysis. In addition, the vulnerability of the fuel tank was re-enacted through vibration durability test results, and the scale factor was applied to the standard load. In order to predict the vibration durability performance required for detailed design, vibration fatigue analysis was performed on the developed vehicle with the frequency of vibration severity equivalent to the durability test, and the vulnerability and life span of the fuel tank were identified through the process of applying weights to these selected standard loads, thereby reducing the test time of the development vehicle.