• Explosives and Blasting
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• v.37 no.1
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• pp.14-23
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• 2019

It has been an always issue for the blasting or the impact analysis to consider the strength characteristics of the rock materials associate with loading rate dependency. Due to the nature of transient loading, the dynamic rock test requires a careful technique to achieve the stress equilibrium state of the specimen. In this study, to investigate the relationship between the rock dynamic strength and the stress equilibrium state, a series of dynamic uniaxial compression tests for Pocheon granite were performed. As a result, the unbalanced stress state on the specimen can lead to the premature failure on the specimen and the less estimation of dynamic strength characteristic as well as the overestimation of strain rate. Consequently, a careful consideration of rock fracture process to achieve the dynamic force balance on the specimen should be required to make an reasonable evaluation of rock dynamic strength.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.320-320
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• 2016

Nanocrystalline Carbon thin films have numerous applications in different areas such as mechanical, biotechnology and optoelectronic devices due to attractive properties like high excellent hardness, low friction coefficient, good chemical inertness, low surface roughness, non-toxic and biocompatibility. In this work, we studied the comparison of pure DC power and pulsed DC power in plasma sputtering process of carbon thin films synthesis. Using a close field unbalanced magnetron sputtering system, films were deposited on glass and Si wafer substrates by varying the power density and pulsed DC frequency variations. The plasma characteristics has been studied using the I-V discharge characteristics and optical emission spectroscopy. The films properties were studied using Raman spectroscopy, Hall effect measurement, contact angle measurement. Through the Raman results, ID/IG ratio was found to be increased by increasing either of DC power density and pulsed DC frequency. Film deposition rate, measured by Alpha step measurement, increased with increasing DC power density and decreased with pulsed DC frequency. The electrical resistivity results show that the resistivity increased with increasing DC power density and pulsed DC frequency. The film surface energy was estimated using the calculated values of contact angle of DI water and di-iodo-methane. Our results exhibit a tailoring of surface energies from 52.69 to $55.42mJ/m^2$ by controlling the plasma parameters.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.86-91
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• 2016

To solve the problem of the excessive error caused by using a single value for the shielding effect of the neutral line of an electric power distribution line in the calculation of the voltage it induces in a telecommunication line, the general expression that was previously developed to reflect the mechanism of voltage induction by a distribution line with multiple grounds is employed in this paper to represent the relationship between the leakage current rates at each ground pole. In this way, the formula for calculating the shielding effect of the neutral line can be factorized against the unbalanced current flowing in the neutral line, which is the root current of induction. This shielding coefficient of the neutral line is not constant, but can vary when a range of induced voltages is generated in the whole power distribution line. The calculation method developed herein reduces the error rate to one tenth of that of the existing calculation result in the case of overestimation and increases it by 14% in the case of underestimation.

• Journal of the Korea Society of Computer and Information
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• v.17 no.1
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• pp.211-218
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• 2012

Fossil fuel is used all over the world and it produces greenhouse gases due to fossil fuel use. Therefore, it cause global warming and is serious environmental pollution. In order to decrease the environmental pollution, we should use renewable energy which is clean energy. Among several renewable energy, wind energy is the most promising one. Wind power generation is does not produce environmental pollution and could not be exhausted. However, due to wind power generation has irregular power output, it is important to predict generated electrical energy accurately for smoothing wind energy supply. There, we consider use ramp characteristic to forecast accurate wind power output. The ramp increase and decrease rapidly wind power generation during in a short time. Therefore, it can cause problem of unbalanced power supply and demand and get damaged wind turbine. In this paper, we make prediction models using power ramp rate as well as wind speed and wind direction to increase prediction accuracy. Prediction model construction algorithm used multilayer neural network. We built four prediction models with PRR, wind speed, and wind direction and then evaluated performance of prediction models. The predicted values, which is prediction model with all of attribute, is nearly to the observed values. Therefore, if we use PRR attribute, we can increase prediction accuracy of wind power generation.

• Journal of the Korea Society of Computer and Information
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• v.18 no.6
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• pp.29-36
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• 2013

In wireless sensor networks, energy is the most important consideration because the lifetime of the sensor node is limited by battery. Most of the existing energy efficient routing protocols use the minimum energy path to minimize energy consumption, which causes an unbalanced distribution of residual energy among nodes. As a result, the power of nodes on energy efficient paths is quickly depletes resulting in inactive. To solve these problems, a method to equalize the energy consumption of the nodes has been proposed, but do not consider the link error rate in the wireless environment. In this paper, we propose a uniform energy consumption of cluster-based multi-hop routing mechanism considering the residual energy and the link error rate. This mechanism reduces energy consumption caused by unnecessary retransmissions and distributes traffic evenly over the network because considering the link error rate. The simulation results compared to other mechanisms, the proposed mechanism is energy-efficient by reducing the number of retransmissions and activation time of all nodes involved in the network has been extended by using the energy balanced path.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.186-186
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• 2000

After LeComber et al. reported the first amorphous hydrogenated silicon (a-Si: H) TFT, many laboratories started the development of an active matrix LCDs using a-Si:H TFTs formed on glass substrate. With increasing the display area and pixel density of TFT-LCD, however, high mobility TFTs are required for pixel driver of TF-LCD in order to shorten the charging time of the pixel electrodes. The most important of these drawbacks is a-Si's electron mobiliy, which is the speed at which electrons can move through each transistor. The problem of low carier mobility for the a-Si:H TFTs can be overcome by introducing polycrystalline silicon (poly-Si) thin film instead of a-Si:H as a semiconductor layer of TFTs. Therefore, poly-Si has gained increasing interest and has been investigated by many researchers. Recnetly, fabrication of such poly-Si TFT-LCD panels with VGA pixel size and monolithic drivers has been reported, . Especially, fabricating poly-Si TFTs at a temperature mach lower than the strain point of glass is needed in order to have high mobility TFTs on large-size glass substrate, and the monolithic drivers will reduce the cost of TFT-LCDs. The conventional methods to fabricate poly-Si films are low pressure chemical vapor deposition (LPCVD0 as well as solid phase crystallization (SPC), pulsed rapid thermal annealing(PRTA), and eximer laser annealing (ELA). However, these methods have some disadvantages such as high deposition temperature over $600^{\circ}C$, small grain size (<50nm), poor crystallinity, and high grain boundary states. Therefore the low temperature and large area processes using a cheap glass substrate are impossible because of high temperature process. In this study, therefore, we have deposited poly-Si thin films on si(100) and glass substrates at growth temperature of below 40$0^{\circ}C$ using newly developed high rate magnetron sputtering method. To improve the sputtering yield and the growth rate, a high power (10~30 W/cm2) sputtering source with unbalanced magnetron and Si ion extraction grid was designed and constructed based on the results of computer simulation. The maximum deposition rate could be reached to be 0.35$\mu$m/min due to a high ion bombardment. This is 5 times higher than that of conventional sputtering method, and the sputtering yield was also increased up to 80%. The best film was obtained on Si(100) using Si ion extraction grid under 9.0$\times$10-3Torr of working pressure and 11 W/cm2 of the target power density. The electron mobility of the poly-si film grown on Si(100) at 40$0^{\circ}C$ with ion extraction grid shows 96 cm2/V sec. During sputtering, moreover, the characteristics of si source were also analyzed with in situ Langmuir probe method and optical emission spectroscopy.

• Journal of Korean Society of Transportation
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• v.22 no.6
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• pp.35-47
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• 2004

Using data envelopment analysis, this paper annually estimates Malmquist total factor productivity indices and decomposes them into productive efficiency change, technical change, and scale change components for three publicly-owned rail transit properties: the Seoul Subway Corporation(SSC), the Seoul Metropolitan Electrified Railways Sector of Korea National Railroad (SMESRS) and the Busan Urban Transit Authority (BUTA). The paper then conceptualizes that the property produces a single output(car-kilometers) using four inputs(labor, electricity, car and maintenance, and track) and uses unbalanced panel data consisted of annual observations on SSC, SMESRS and BUTA. The results show that the average annual growth rate of productivity of the three properties is 6.6 percent, which is 0.5 percent less than the average annual increasing rate of their labor price. They also show that the greatest part of the growth in productivity is explained by technical change and to a lesser degree by scale change and changes in productive efficiency though each of the three components contributes more than 20 percent to the growth in productivity, These results suggest that the three properties should base the increasing rate of their wages on the growth rate of their productivity and utilize existing technologies more efficiently prior to introducing new ones to raise their productivity, and that all the three components should be considered to evaluate their productivity more correctly.

• Journal of Arbitration Studies
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• v.20 no.3
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• pp.93-120
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• 2010

In 1978, Chinese reform and opening caused a big changes in Chinese labor relationship. Through reforming and opening, China gave up part of state ownership system and group ownership system, permitted private ownership system, and also opened the way for capitalists to ride again. Since China was established, the labor relationship ceased for 30 years has been appeared. However because the top priority aim of China's reform was economic growth, the protection of the rights and interests of labor was pushed back on the policy priority list. China takes foreign capitals based on cheap labor force quickly and China come up the worldwide plants. Since reformed, China keeps an economic growth rate of 9.7% annually for 30years. This economic growth is based on labor's sacrifice. However, Chinese fast economic growth causes side effects such as increasement of the gap between the wealthy and the poor, increasement of unbalanced development between regions, and the increasement of conflict between labor and management. Especially, according to changes in labors' level of consciousness, the labors recognized that their rights and interests are exploited by employers. Therefore, the labor dispute is continuously increasing. Chinese government changes their policy from the policy focusing on enterprise development to the policy protecting labor's rights and interests. In order to protect labor's rights and interests, China conducts labor contract law and labor dispute conciliation arbitration law in 2008. This kind of changes in Chinese labor environment affect a lot to Korean companies which already entered into China or are willing to enter. According to studying on present situation and resolution system in Chinese labor dispute, this paper suggests the proper countermeasure related to labor dispute of Korean companies which entered in China. First, the success rate of labor dispute conciliation by enterprise labor dispute conciliation committee is around 20% during recent several years and the success rate by year is in decline. Therefore, when labor dispute is occurred, our companies which entered into China better use other labor dispute methods such as negotiation and arbitration than conciliation in order to settle a conflict. Second, from the Korean enterprises entered in China point of view, there exists a problem not to sue except special cases which provided in the law even though they are dissatisfied with arbitrate judgment. Thus, when labor dispute occurred, Korean enterprises try to do best to settle the dispute through negotiation. However, in case of that the dispute cannot be settled by negotiation, they have to attend in the arbitration as if it is a last chance. Third, Korean enterprises keep in mind that dispute handling procedures between labor union and users or between labor group and users are different, and then deal with separately. Thus, dispute between labor and users have to follow arbitrate procedures as a necessary procedure, but in case of dispute related to group contract, namely dispute against labor union, labor dispute can be settled by arbitrate or suit, so after figuring out the situation exactly, it is necessary to select more advantageous way in order to settle the dispute. Moreover, in case of the dispute between labor union, they have to keep in mind that conciliation procedures cannot be used.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.3
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• pp.159-171
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• 2016

Purpose: This study investigated medical accessibility on optical stores and ophthalmic clinics of Seoul Special City and six other metropolitan cities. Methods: By using a number of households, population, optician stores, ophthalmic hospitals, and real estate (apartments) standard market price of Seoul Special City and six other metropolitan cities provided by the Commercial District Information System (2016.6) of Small Enterprise & Market Authority, we analyzed the level of healthcare accessibility and business area zones, Statistical analyses were performed with SPSS 18.0. Results: Inchon (household 2,227/population 5,723) had the highest household and population rate per optical store, and Gwangju (1,146/2,979) had the lowest. Gwangju (24,612/63,987) had the highest household and population rate per optical store, and Seoul (10,021/24,432) had the lowest. From the consumer and patient's point of view, lower household rate per optical store is a city with good accessibility to healthcare, but from an optical store and ophthalmic clinic's view, it will have great difficulty due to issues of competition. Conclusions: Consumers and patients should be the center of healthcare. A healthcare system that can provide smooth service anywhere anytime should be constructed. However, most metropolitan cities, including Seoul, have optical stores and ophthalmic clinics densely populated where profitability and liquidity are ensured and causing unbalanced distribution of healthcare. To solve such problems, we need proper distribution of optician stores according to the population proportion and industrial-educational research to find balance point of local healthcare.

• Environmental and Resource Economics Review
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• v.19 no.2
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• pp.413-440
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• 2010

Since 2000, as importance of sourcing energy emphasized caused by instability of international oil price, interests toward Caspian countries as an alternative markets has increased. Especially, Azerbaijan, as middle Asian emerging exporting country, has performed drastic economic boom because of massive amount of foreign capital flowed in and construction of BTC pipeline. However, despite this economic surge, there are unbalanced economy which is merely focusing on energy industry and pressure from increase in real exchange rate and inflation. In order to analyze the sustainability of Azerbaijan economy, the total sample time period of this paper is from January 2001 to December 2007 and the term is divided into before and after BTC line construction. Vector Error-Correction Model has been applied to analysis confirming short-term and long-term effect. As a result, Azerbaijan now face the symptoms of the recession during the time period and this is due to high oil price and increase in export influenced by BTC oil pipeline resulting in decrease in real interest rate. This conclusion is to affect competitiveness of manufacturing industry, base industry for economic proliferation, in a negative way.