• Journal of the Korean Society of Safety
• /
• v.13 no.3
• /
• pp.11-23
• /
• 1998

In this study, collapse test of thin-walled structure is performed under axially quasi-static and impact load in collapse characteristic to develop the optimum structural member for a light-oriented automobile. Furthermore, the energy-absorbing capacity is observed according to the variety of configuration(circular, square), aspect ratio in aluminum specimen to obtain basic data for the improved member of vehicle. In both quasi-static and impact collapse test, Al circular specimens collapse, in general, with axisymmetric mode in case of thin thickness while collapse with non-axisynmetric mode according to the thickness increase. For Al rectangular specimens, they collapse with axisymmetric mode in case of thin thickness, with mixed collapse mode according to the increase of thickness. In terms of initial max. load, Al square specimen turns out the best member among specimens, and then Al square, circular and circular with large scaling ratio, respectively. In case of quasi-static compression test, the absorbed energy per unit volume and mass shows higher in Al circular specimen, and then Al square, circular with large scaling ratio, respectively, according to shape ratio the absorbed energy per unit volume and mass in case of max. impact compression load is higher than that of static load. But the absorbed energy per unit volume and mass shows that Al circular specimen is the best member. Especially, unlike max. compression loan, the absorbed energy per unit volume and mass in impact test turns out the low value.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.1
• /
• pp.81-91
• /
• 2021

This paper investigates the long run hedging ability of precious metals against the risks associated with adverse conditions of economic and financial variables for Pakistan, the USA, China, and India. Monthly data of gold, silver, platinum, stock returns, exchange rate, industrial production, and inflation was collected for the selected economies. Saikkonen and Lutkepohl (2002) unit root test was employed to access the unit root properties of the data series and identify the break dates. Furthermore, this study used the Johansen cointegration test with and without structural breaks to identify the long-run relationship between metals prices and different financial and economic variables. The findings suggest that the time series under study have unit root problem at level with and without structural breaks. Without considering structural breaks, the Johansen trace test indicates that in Pakistan and China, gold, silver, and platinum hold a cointegrating relationship with macroeconomic and financial variables. For the US, gold indicates cointegration which supports the hedging ability of gold against inflation, stock, and industrial production in the long run. The results of the cointegration test after incorporating the structural breaks provide even stronger evidence of the long-run relationship of precious metals and consumer prices, exchange rate, and stock prices.

• Journal of Korean Society on Water Environment
• /
• v.31 no.3
• /
• pp.235-240
• /
• 2015

To evaluate the unit load generation and discharge, pig cage test was conducted. Feed intake, drink amount, and urine generation increased growth stage (heavy weight) of the pig more great. However, the sum of the urine and manure did not show a significant difference in the growth stages of pigs. Because of the limit of the experiment, e.g., research period, high pigpen temperature, breed-related stress and etc., it could not be derived the results of the four seasons. Therefore, in order to generalize the results, the feed intakes were calibrated using a NRC (National Research and nutritional requirements of pigs from the Commission) standards. The finalized unit load generation and generation amounts of manure and urine were estimated at BOD 104.1 g/head/d, T-N 21.2 g/head/d, T-P 4.9 g/head/d, manure 0.96 L/d, urine 1.66 L/d with consideration of revised feed intake. Compare to the former research results of MOE (Ministry of Environment, 1999) and NIAS (National Institute of Animal Science, 2008), the generation amounts of manure and urine were similar to the NIAS's values. In case of unit load generation, BOD and T-N were almost similar in all of them. However, the T-P unit load generation of MOE was more difference, e.g., 2.5 times high, compare to this study.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.20 no.12
• /
• pp.1210-1215
• /
• 2010

Unit cabin means room, which is installed in the high value-added vessel such as drill ship, offshore platform and FPSO, after pre-assembled. In order to develop the noise control design for a unit cabin, a variety of acoustic tests such as sound absorption, transmission and radiation measurements were carried out by using the deckhouse mock-up. From the tests, it was found out that the sound transmission loss between cabin and corridor was 13 dB below than FPSO standard and the combined noise level of the unit cabin was dominated by the radiated noise from wall panel in low frequency range. Based on the test results, design guidelines for the noise control of the unit cabin were fully established, such as the improvement of sound transmission loss between the cabin and corridor, and radiated cabin noise reduction.

• Aerospace Engineering and Technology
• /
• v.7 no.2
• /
• pp.176-186
• /
• 2008

As determined single coaxial cable for the interface between satellite and ground station in COMS RF compatibility test, RF supporting unit was required to allow signals in different frequency-band to be exchanged in the single coaxial cable. In addition, the path loss between satellite and ground station in normal operation should be simulated through two RF supporting units connected to the ends of single coaxial cable. As an effort to design RF supporting unit, level diagram was firstly conducted on the basis of measured data for each element. From the level diagram, it was found that single coaxial cable connected with two RF supporting units properly represented the path loss between satellite and ground station After RF supporting unit was integrated on aluminum plate, it was tested that input signal level at each test cap linked with MODCS and TC&R was tunable within the required dynamic range. RF supporting unit, now completely integrated, will be applied in the upcoming COMS RF compatibility test.

• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.1309-1313
• /
• 2008

This paper suggests an example of modification of the durability test specifications of electronic control unit for an automotive system in phase of design validation. The basic concept to redefine the specifications of durability test is based on the Arrhenius relationship for accelerated temperature test and the modified Coffin-Manson model for temperature cycle test. The ambient temperature of the powered-event durability test is increased to reduce the required test time of the current specification. Furthermore, the holding time between the events to cool down the temperature of the components is shortened and the resultant temperature rise affects the durability of the components. Thus, the acceleration factor due to the increased temperature range of temperature cycle is also estimated by the modified Coffin-Manson model.

• Proceedings of the KIPE Conference
• /
• 1999.07a
• /
• pp.118-121
• /
• 1999

In this pager, we studies IGBT VVVF inverter for 1C4M propulsion system of railway traction. This inverter is consisted in inverter stack, DB unit, and control unit. To prove performance of inverter carry out combine test. This test verifies that performance of inverter is excellent.

• Communications for Statistical Applications and Methods
• /
• v.3 no.1
• /
• pp.257-265
• /
• 1996

We consider nonstationary autoregressive autoregressive process with infinite variance of error. In the case of infinite cariance, the limiting distribution of the estimated coefficient is different from that under the finite cariance assumption. In this paper we show that the bootstrap method can be used to approximate the distribution of ordinary least squares estimator of the coefficient in the first order random walk process with infinite variance through some empirical studies and we suggest a test procedure based on bootstrap method for the unit root test.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.1163-1168
• /
• 2008

Automatic Train Protection(ATP) System is developed by ETCS(European Train Control System) CONSORTIUM for unify Europe railway system. ATP system is composed of Eurobalise and EuroATC. Nowadays, Korea construct ATP system in conventional line and new electrical locomotives also install ATP system. It is important to verify quality which form checklist during Factory Acceptance Test at beyond the seas. In this paper, review the process, test item, norm and checklist for the Balise Transmission Module, Compact Antenna Unit, Vehicle Control Unit and Communication Controller at the Plymouth Bombardier and Vasteras enics factory.

• International Area Studies Review
• /
• v.14 no.3
• /
• pp.363-387
• /
• 2010

This papers studies the causalities and effects on the relationship between inbound tourism(TOU) and the production amount of service industry in China, using the unit root test, the Granger causality test, the cointegration test, and VECM. we take their natural logarithm and define them as TOU and SGDP: these represent the distributed variable based the lagged values of the number of international tourists by continent and real production amount in service industry of China, respectively. The results of empirical study of this papers are as follows: Firstly, in the unit root test, we found that each time series was unstable one that has unit root. This result made me use 1st differenced data for this empirical study. Secondly, in the Granger casuality test, the study results show that there is unilateral casuality relation between DLSGDP-$DLTOU_i$ except DLSGDP-DLTOUL model for the same time, while no casuality relation between DLTOU-DLSGDP for all models of China. Thirdly, there is cointegration relation between all models for the period of 1980-2008.