• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.16-21
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• 2002

The high speed machining center(HMC) has been widely applied to manufacture a die and trial product in many machine industry. Because the evaluation fer the HMC is not sufficiently performed and the efficient cutting conditions aren't selected, a great loss has been caused in the cost aspect. In this study, the need of preliminary running time and unstable spindle speed is presented from the analysis of acceleration in idling. The Machinability fur the TiAlN coated flat end mill and STD11( $H_{R}$C60) is evaluated from the trends of tool wear and cutting force according to cutting conditions and slenderness ratio and a low response of tool dynamometer in high speed is proved. The resonance spindle speed is identified through the tool wear and natural frequency test.t.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.894-899
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• 1998

To absorb the deformation of live load, thermal gradient, shrinkage and creep in bridge structures and general structures, expansion joint has to be established. Especially expansion joint for high-speed railway bridge has to accomodate the static and dynamic forces and it not only has the durability of itself but also maintain the durability of structure by preventing the leakage of water. The actual used product of expansion joint for high-speed railway bridge is only ones made in France, Germany and Japan. In this study, the development process and test results of developed expansion joint are introduced which has the functional operation and durability enough to apply to high-speed railway bridges, roadway bridges and general structures. The tests consist of fatigue-durability test of 3 million times by high-speed rail load, leakage test and jack-up test for verifying the possibility of exchanging it. The performance of developed expansion joint satisfy the specification of Korea High Speed Rail Construction authority.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.147-150
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• 1995

High speed machining one of the most effectiv to improve machining accuracy and product in dies and mould. But a study on this is limited to Alumium, light metal etc. This paper presents machining characteristic of gray cast iron in high speed machining with tungsten carbide endmill. It is suggested to measure sutting force, tool wear, surface roughness, surface shape and select of cptimal cutting condition in the high speed machining of gray cast iron. Performance of high speed machine tool was estimated and the relationship between cutting phenomenon and machinabillity was described.

• Design & Manufacturing
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• v.17 no.4
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• pp.14-23
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• 2023

The electric vehicle market is developing rapidly around the world. Also, parts of electric vehicles require precision.In order to produce high-precision motor cores,Press equipment must also have good precision. Drive motor cores are an important technology for electric vehicles. It uses a large high-speed press to mass-produce drive motor cores. Because it's a large high-speed press, there are many reasons why the precision is not good. One of the causes is vibration and noise. Recently, as environmental demands have become stricter, regulations on noise and vibration have been strengthened. It is important for press machines to reduce vibration first for sound insulation and dust proofing. This is because the "breakthrough" phenomenon occurs in the press. Dynamic precision is the precision under the load of the press, Design considering strain and stiffness shall be made. Vibration and noise may occur due to SPM of high-speed press,And vibration and noise can cause structural deformation of the press. Structural deformation of the press can affect the precision of the product.Noise and vibration also cause problems for workers and work environments. Problems with vibration and noise occur during press processing, and vibration and noise lead to damage to the mold or defects in the product. Reliability in high-quality technology must be secured with low noise and low vibration during press processing. Modular shape and deformation energy effects were analyzed through finite element analysis. In this study, a study on vibration and noise countermeasures was conducted through finite element analysis of a large high-speed press.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1710-1714
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• 2005

Micro Cellular Plastics create a sensation at polymer industrial for lowering product cost & overcoming a lowering of mechanical intensity. This research is surface quality research of MCPs product Through surface rough measurement. This experiment is carried out according to injection speed control with the surface rough & Product surface quality are searched

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.313-314
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• 2006

Indicating product quantity by real time can be benefit both worker and management. Worker can compare real product quantity with its target and can adjust working speed to match with goal. Therefore, so called JPH equipment developed to indicate target quantity of product. As a main processor PIC16F877 was used and FND display were used to indicate current time, elapsed time, JPH value and target amount of product. Values like JPH and starting time, etc. are can easily be set by $4{\times}4$ numeric keypad and display datum likes target amount of product, current time and elapsed time, etc are displayed on FND by RS232 serial transmit. The operation of JPH equipment are tested and verified through long term test and are proved acting properly on working conditions.

• International journal of advanced smart convergence
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• v.13 no.1
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• pp.185-193
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• 2024

This study aimed to investigate the immediate physiological responses, including heart rate, blood pressure, and rate pressure product (RPP), following squat exercises performed at three water depths (ground, knee depth, waist depth) and two speed conditions (60bpm speed, Max speed). The participants consisted of 10 men in their 20s with over 6 months of resistance exercise experience. For the 60bpm speed squats, participants performed 30 repetitions in 1 minute at a rate of 2 seconds per repetition, while for Max speed squats, they performed at Max speed without a set limit on the number of repetitions for 1 minute. All experiments were conducted with a random assignment. The study results showed that immediately after the aquatic squat exercise, the average heart rate, blood pressure, and cardiac load were higher in the order of knee depth, ground level, and waist depth at both 60bpm speed and Max Speed. At 60bpm speed, the heart rate was higher in the order of ground level, knee depth, and waist depth. Overall, exercise in an aquatic environment was considered to impose relatively lower physical burden compared to land-based exercise. Therefore, it is suggested that depending on individual fitness levels and exercise goals, appropriately combining aquatic exercise, which imposes lower immediate physiological burden, and land-based exercise may lead to safer and more effective exercise methods.

• The Research Journal of the Costume Culture
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• v.21 no.1
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• pp.117-128
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• 2013

Studies show that time pressure affects the purchase decision-making process of consumers. However, in the case of apparel shopping, few studies have looked into the influence of time pressure on the purchase decision-making process. This study aims to determine how perceived time pressure in apparel shopping, time pressure situations, and product type and the interactions between these variables influence the clothing purchase process. An empirical study was conducted among males and females in their 20s and 30s. Perceived time pressure in apparel shopping was measured using four items. Time pressure situations and product types were given in the form of scenarios. A $2{\times}2{\times}2$ experimental design was used, and perceived time pressure in apparel shopping, time pressure situations, and product type were used to create eight different situations. The dependent variables included decision-making speed, anticipated regret, and anticipated purchase satisfaction. Data from 512 subjects were collected through an online data collection. Results showed that the high perceived time pressure group and the shopping situation with time pressure involved a significantly high level of decision-making time, anticipated regret, and anticipated purchase satisfaction. Marketers must understand the real-time pressure situations of consumers.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1799-1802
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• 2003

The commercial success of a new product is influenced by the time to market. Shorter product leadtimes are of importance in a competitive market. This can be achieved only if the product development process can be realized in a relatively small time period. New cutting inserts are developed by a time consuming trial and error process guided by empirical knowledge of the mechanical cutting process. The effect of previous cutting on chip formation and the surface residual stresses has been studied. The chip formation is not affected much. There is only a minor influence from the residual stress on the surface from tile first cutting on the second pass chip formation. Thus, it is deemed to be sufficient to simulate only the first pass. The influence of the cutting speed and feed on the residual stresses has been computed and verified by the experiments. It is shown that the state of residual stresses in the workpiece increases with the cutting speed. This paper presents experimental results which can be used for evaluating computational models to assure robust solutions. The general finite element code ABAQUS/Standard has been used in the simulations. A quasi-static simulation with adiabatic heating was performed. The path for separating the chip from the workpiece is predetermined. The agreement between measurements and calculation is good considering the simplifications introduced.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1033-1039
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• 2013

Recently, as the product life cycle becomes shorter and customer needs becomes various, it has a great difficulty in managing the product information without the information technology. In this paper, we discuss how to classify numerous BOMs types and propose three categories-Structure-BOM, Display-BOM and Function-BOM for BOMs classification. Based on this result, we design the integrated BOMs management system with ERD(Entity-Relaion-Daiagram) model. This paper presented the methodology for management speed-up and communication innovation in the automotive industry, which incorporated the enterprise-wide product information. The proposed enterprise-BOM design methods also systemized the data related to automotive's principal attributes such as types of levels, options, colors, and consumers' orders. Efficient and flexible development of products can be achieved in the frequently varying environment of products.