• Transactions of Materials Processing
• /
• v.12 no.5
• /
• pp.473-478
• /
• 2003

This study presents the enhancement of forgeability of SNCM522H materials. Target parts are output shaft(OP shaft) used as components of power train for automobiles. To carry out cold forging process of OP shaft by 1 pass instead of existing 2 pass process, studies in terms of process design and heat treatment were performed. To introduce the new process, the finite element method was accomplished, and to assess the validity of proposed heat treatment cycle, several experiments(hardness test, observation of optical microstructures, tensile test) were carried out. The 2Pass forging process could be reduced as lPass process through improvement of process and heat treatment technology and that would give cost reduction.

• 한국신재생에너지학회:학술대회논문집
• /
• 2006.06a
• /
• pp.225-227
• /
• 2006

The demand for developing the compact and cost effective commercial version of the photovoltaic power conditioning system(PCS) is now increasing and several commercial products are on the markets. In this paper, several design results of 10kW rated grid-tied photovoltaic PCS system are introduced, and several test results for the system evaluation are also described. The test results verified the validity of the proposed photovoltaic PCS system.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.20 no.7
• /
• pp.644-650
• /
• 2010

Among various elements to affect customer's evaluation of vehicle quality, BSR(Buzz, Squeak, Rattle) are considered to be a mostly contributing factor. In this paper, we provide the test method which can be used to reduce the BSR noise of instrument panel in a vehicle. First, potential source regions of the instrument panel for BSR are localized by using the vibration-excitor and near-acoustic field visualization system. Then, subjective evaluation of BSR noise from the detected potential noise source regions is made with the Zwicker's loudness and time-varying loudness methods. This illustrative analysis reveals that current experimental methods can be used as a test procedure to systematically tackle BSR issues in early stage of the vehicle development cycle, which can result in the reduction of the production cost.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 1997.11a
• /
• pp.219-226
• /
• 1997

This paper investigates and analyzes the installation and failure status of mold transformer being used in domestic subways and describes the extinguishing process by time through the combustion test of winding part of mold transformer. Condition of installed mold transformers and classes of fire were surveyed and the mold transformer was burned in a horizontal heating furnace. It was confirmed that the mold transformer is self extinguishing and nonflammability. According to this results, the suitable standard of fire protection for the mold transformer was demanded after review of domestic and abroad law. It is expected that the cost of fire protection equipment can be reduced by using the status and combustion test result of mold transformer.

• Transactions of The Korea Fluid Power Systems Society
• /
• v.5 no.3
• /
• pp.15-22
• /
• 2008

The road simulators have become common tools within the automotive industry for evaluation of vehicle and vehicle system durability performance. These simulators need appropriate input signal generation algorithms to realize the actual driving conditions due to non-linear vehicle and test rig behaviour. Although somewhat unconventional from a control standpoint, the iteration approach has proven to be a very effective method for control of complex, multiple degree-of-freedom systems where the tracking parameter is known a priori. In this paper, the road profile replication algorithm is verified by applying Belgian road to the developed road simulator. The simulation and experimental results are included to evaluate the performance of this simulator. This road simulator provides considerable savings in cost, development time, and testing risk during developing automotive components.

• Journal of Aerospace System Engineering
• /
• v.9 no.3
• /
• pp.8-11
• /
• 2015

Since the late 1990's, FAA, NASA and the aerospace industry have worked together to develop the sharing system of the composite material qualification databases which were obtained through the standardized fabrication and testing procedures. The result was what is now known as the AGATE(Advanced General Aviation Transport Experiments) or NCAMP(National Center for Advanced Materials Performance) methodology, a more cost-effective concept that shifts the major responsibility for qualification and testing from the aircraft manufacturer to the material supplier. The properties of composite materials are largely dependent on the testing as well as the raw material properties and the manufacturing process including the process control parameters. Thus it is important in the composite material qualification to comply with the standardized testing procedures. In this paper, I will describe the standardized witness methodologies of certification engineers to reduce the effect of testing variability within the qualification data.

• Proceedings of the SAREK Conference
• /
• 2006.06a
• /
• pp.1186-1190
• /
• 2006

Rising in important of alternative energy due to the recenfly high oil price and environment problem. Application of alternative energy has become higher than before. In this study, facility test of Geothermal energy to bankfiltration was examined appliying changwon pumping well. Initial installation cost was efficiently saved by connecting a heat pump system to pumping well in changwon bankfiltration site. A falling-off in efficiency of heat pump was free due to the bankfiltration that is rare for the temperature fluctuation. Therefore, Heat soure as bankfiltration system solve the existing facilities problems of geothermal heat pump system.

• Journal of Information Processing Systems
• /
• v.15 no.4
• /
• pp.920-930
• /
• 2019

To figure out the impact of debt financing on the profits of industrial enterprises, it starts with calculating the first differences against the logarithms of the cost profit ratios and the debt asset ratios of Chinese industrial enterprises during 179 months from 2002 to 2016; next, it runs the cointegration test and afterwards the regression test to analyze the obtained first differences, and still next uses the Simulink software to get the regularity of those changes. It finds out that there is not only a long-term stable relationship between the enterprises' profits and debts, but also a steady time series trend within a short term. The profit rate positively correlates to the debt asset ratio, and profit for the current term positively correlates to the profit for the previous term. It indicates that properly raised debts can help increase the profit rate of the industrial enterprises, and a higher previous profit level can help improve the current profit level.

• Smart Structures and Systems
• /
• v.30 no.2
• /
• pp.209-219
• /
• 2022

The determination for bearing capacity of precast nodular piles is conventionally time-consuming and high-cost by using numerous experiments and empirical methods. This study proposes an intelligent method to evaluate the bearing capacity and shaft resistance of the nodular piles with high efficiency based on long short-term memory (LSTM) approach. A series of field tests are first designed to measure the axial force, shaft resistance and displacement of the combined nodular piles under different loadings, in comparison with the single pre-stressed high-strength concrete piles. The test results confirm that the combined nodular piles could provide larger ultimate bearing capacity (more than 100%) than the single pre-stressed high-strength concrete piles. Both the LSTM-based method and empirical methods are used to calculate the shift resistance of the combined nodular piles. The results show that the LSTM-based method has a high-precision estimation on shaft resistance, not only for the ultimate load but also for the working load.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.17 no.1
• /
• pp.16-30
• /
• 2023

The elderly population is increasing owing to a low fertility rate and an aging population. In addition, life expectancy is increasing, and the advancement of medicine has increased the importance of health to most people. Therefore, government and companies are developing and supporting smart healthcare, which is a health-related product or industry, and providing related services. Moreover, with the development of the Internet, many people are managing their health through online searches. The most convenient way to achieve such management is by consuming nutritional supplements or seasonal foods to prevent a nutrient deficiency. However, before implementing such methods, knowing the nutrient status of the individual is difficult, and even if a test method is developed, the cost of the test will be a burden. To solve this problem, we developed a questionnaire related to nutrient classification twice, based upon which an adaptive algorithm was designed. This algorithm was designed as a machine learning based algorithm for nutrient classification and its accuracy was much better than the other machine learning algorithm.