• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.1
• /
• pp.43-50
• /
• 2016

NAND flash based storage devices adopts multi-channel and multi-way architecture to improve performance using parallel operation of multiple NAND devices. However, multiple NAND devices consume higher current and peak power overlap problem influences on the system stability and data reliability. In this paper, current waveform is measured for erase, program and read operations, peak current and model is defined by profiling method, and estimated probability of peak current overlap among NAND devices. Also, system level TLM simulator is developed to analyze peak overlap phenomenon depending on various simulation scenario. In order to remove peak overlapping, token-ring based simple power management method is applied in the simulation experiments. The optimal peak overlap ratio is proposed to minimize performance degradation based on relationship between peak current overlapping and system performance.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.16 no.4
• /
• pp.361-372
• /
• 2014

A measurement of tunnel displacement plays an important role for stability analysis and prediction of possible fault zone ahead of tunnel face. In this study, we evaluated characteristics of tunnel behaviour due to the existence and orientation of fault zone based on 3-dimensional finite element numerical analysis. The crown settlement representing tunnel behaviour is acquired at 5 m away from tunnel face in combination with x-Rs control chart analysis based on statistics for trend line and L/C (longitudinal/crown displacement) ratio in order to propose risk management method for fault zone. As a result, x-Rs control chart analysis can enable to predict fault zone in terms of existence and orientation in tunnelling.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.10
• /
• pp.109-117
• /
• 2021

This study investigates the effects of FDI and other macroeconomic variables on Total Factor Productivity (TFP) in selected ASEAN+3 countries from 1981 till 2016. Total Factor Productivity (TFP) for each ASEAN+3 country was constructed using the Malmquist productivity index method. Then, a panel ARDL framework (dynamic heterogeneous panel), namely Pooled Mean Group (PMG), Mean Group (MG), and Dynamic Fixed Effect (DFE) are employed in examining the effects of FDI and other controlling variables on TFP. The new findings show that FDI has a significant and positive impact on TFP in the long run and the short run in ASEAN+3 countries. Besides, the results also reveal that in the long run, other variables such as the average number of years of schooling and the ratio of high-skilled to low-skilled labor also have a significant and positive effect on TFP. However, economic openness, government expenditure on R&D, and interaction between countries and FDI have a negative and significant impact on TFP. These findings implied that the recipient countries must ensure their political stability and offer various incentives to attract more investors. Furthermore, the influx of foreign investors, especially large ones and lower costs, should be encouraged by each country as FDI inflows can boost their TFP growth.

• Journal of the Korean GEO-environmental Society
• /
• v.24 no.11
• /
• pp.19-24
• /
• 2023

Ground anchor has been widely used specially for maintaining stability on reinforced cut slope in expressway. While the durability of the ground anchors should be ensured over the service life. However, the long-term loss of tensile force has occurred in most of field-installed anchors. Main causes are not clearly identified and very few studies have been made for analyzing long-term behavior of ground anchor in slopes. In this study, full-scale model tests and long-term measurements were made to obtain the load-displacement data and identified the causes of the long-term behaviors of ground anchor. As a result, the bond strength decreases exponentially with increasing water-binder ratio. Especially, groundwater is the most influencing factor to the bond strength. In the long-term behavior, the load decreases sharply until the initial settlement stabilized, and thereafter the tension force decreases constantly.

• Journal of the Microelectronics and Packaging Society
• /
• v.29 no.4
• /
• pp.41-47
• /
• 2022

Ag sintering technologies have received great attention as it was applied to the inverter of Tesla's electric vehicle Model III. Ag sinter bonding technology has advantages in heat dissipation design as well as high-temperature stability due to the intrinsic properties of the material, so it is useful for practical use of SiC and GaN devices. This study was carried out to understand the sinter joining temperature effect on the robust Ag sintered joints in air without pressure within 10 min. Electroplated Ag finished Cu dies (3 mm × 3 mm × 2 mm) and substrates (10 mm × 10 mm × 2 mm) were introduced, respectively, and nano Ag paste was applied as a bonding material. The sinter joining process was performed without pressure in air with the bonding temperature as a variable of 175 ℃, 200 ℃, 225 ℃, and 250 ℃. As results, the bonding temperature of 175 ℃ caused 13.21 MPa of die shear strength, and when the bonding temperature was raised to 200 ℃, the bonding strength increased by 157% to 33.99 MPa. When the bonding temperature was increased to 225 ℃, the bonding strength of 46.54 MPa increased by about 37% compared to that of 200 ℃, and even at a bonding temperature of 250 ℃, the bonding strength exceeded 50 MPa. The bonding strength of Ag sinter joints was directly influenced by changes in the necking thickness and interfacial connection ratio. In addition, developments in the morphologies of the joint interface and porous structure have a significant effect on displacement. This study is systematically discussed on the relationship between processing temperatures and bonding strength of Ag sinter joints.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.43 no.1
• /
• pp.49-61
• /
• 2007

Otter boards in the trawl are the one of essential equipments for the net mouth to be spread to the horizontal direction. Its performance should be considered in the light of the spreading force to the drag and the stability of towing in the water. Up to the present, studies of the otter boards have focused mainly on the drag and lift force, but not on the stability of otter boards movement in 3 dimensional space. In this study, the otter board is regarded as a rigid body, which has six degrees of freedom motion in three dimensional coordinate system. The forces acting on the otter boards are the underwater weight, the resistance of drag and spread forces and the tension on the warps and otter pendants. The equations of forces were derived and substituted into the governing equations of 6 degrees of freedom motion, then the second order of differential equations to the otter boards were established. For the stable numerical integration of this system, Backward Euler one of implicit methods was used. From the results of the numerical calculation, graphic simulation was carried out. The simulations were conducted for 3 types of otter boards having same area with different aspect ratio(${\lambda}=0.5,\;1.0,\;1.5$). The tested gear was mid-water trawl and the towing speed was 4k't. The length of warp was 350m and all conditions were same to each otter board. The results of this study are like this; First, the otter boards of ${\lambda}=1.0$ showed the longest spread distance, and the ${\lambda}=0.5$ showed the shorted spread distance. Second, the otter boards of ${\lambda}=1.0$ and 1.5 showed the upright at the towing speed of 4k't, but the one of ${\lambda}=0.5$ heeled outside. Third, the yawing angles of three otter boards were similar after 100 seconds with the small oscillation. Fourth, it was revealed that the net height and width are affected by the characteristics of otter boards such as the lift coefficient.

• The Korean Journal of Community Living Science
• /
• v.17 no.4
• /
• pp.81-95
• /
• 2006

This study was made to find out how stress affect on nutrition status of the college freshmen who were experiencing physical growth and development as well as drastic emotional change. 400 male and female freshmen in 4 year colleges were surveyed respectively through the health check-up procedure for college entrance in February, In order to find out the stress in each group frustration, deprivation, lack of self efficacy, type A behavior and anxiety response were surveyed through 10 questions with total 40 points by assigning 4 points for each question. Diet Status was expressed by DDS (Dietary Diversity Score by 5 food groups) and DVS(Dietary Variety Score). 24-hrs recall method was used to find out the quantity of daily nutrient of EAR(estimated adquacy ratio) by KDRIs(Korean Dietary Recommended Intakes). Nutrition level was analyzed by Can-Pro for professionals (Korea Nutrition Association). And for the quality intake, percentage was calculated and MAR(Mean Adequacy Ratio) were produced. Highest point was obtained in the stress of anxiety with the total 40 score of 30.20, and the scores were 29.79, 28.67, and 28.39 for deprivation, type A behavior and frustration respectively. There was no difference of blood components in accordance with stress type. Stress type was divided into less sensitive group and highly sensitive one and the relationship with the blood nutrient status was observed. The difference of blood component and blood pressure in sensitive and highly sensitive groups was observed in deprivation and anxiety. The index of blood pressure(p<0.05), hemoglobin(p<0.01), HDL-cholesterol(p<0.05), and Fe(p<0.05) was high in the deprivation of sensitive group. Blood pressure and hemoglobin was high in type A of sensitive group(p<0.05). And the contents of blood triglyceride was high in the anxiety of sensitive group(p<0.001) The result of nutrition intake analysis according to stress type showed that there was low intake for energy, riboflavin, and niacin. When the degree of deprivation was high there was a lack of riboflavin intake and there was no significant difference of nutrition intake in lack of self efficacy, type A behavior and anxiety response. Thus, it is necessary for colleges to educate the students to maintain mental stability through various programs and activities after catching a kind and extent of the stress college students we meeting with like the confusion of value system, open heterosexual relationship, and the employment difficulties linked with political uncertainty and economic recession.

• Journal of Digital Convergence
• /
• v.19 no.2
• /
• pp.61-69
• /
• 2021

The military pension deficit is increasing due to an increase in the average life expectancy and pension option rate, and a significant reason for this is estimated to be a continued increase in the number of military pension recipients. In terms of the soundness of military pension finances, this paper uses the Markov chain model to validate the stability of the military group, suggesting the direction of future military pension system in terms of the ratio of pension receipts to employees, and verifying the feasibility of the method applied through verification. Through this paper, we have confirmed that the initial 45,270 military personnel converge to 43,141 after a certain period of time and reach a stable state, which is expected to help us to estimate the long term size of military pension recipients to confirm the direction of national financial support. Military man who are eligible for pensions for more than 20 years have a relatively low rate of turnover or retirement compared to ordinary private groups, making it easier to define their status and simplify state transition probabilities. Therefore, it is expected that the sustainability of the military pension will be confirmed from a long term perspective by viewing the military group as a system and applying it to the Markov chain model by checking the probability of transfer of status such as promotion, maintaining the current grade, and retirement during the period.

• Journal of the Korean Society for information Management
• /
• v.35 no.1
• /
• pp.33-59
• /
• 2018

This study draws on the current momentum to diversify open government data research through multidimensional scaling and model development. It formulates a quality assessment model applicable to library open data, taking into consideration the paucity of such research in the field. The model was developed using the Delphi method and verified for validity and reliability on the basis of a survey administered to library open data users. The results of the fourth round exhibited an average of 4.00 for all measured elements and a minimum validity of .75, rendering the model appropriate for use in quality assessments of library open data. The convergence and stability results provided by the expert panel fell below .50, confirming that there was no need to conduct further surveys in order to establish the validity of the Delphi method. The model's reliability likewise garnered results of .60 and above in all three dimensions. This Model completed with the input of the Delphi panel was put through a verification process in which library open data users such as domestic and international librarians, developers, and open data activists reviewed the model for validity and reliability. The model scored low on validity on account of its failure to load all measure factors and elements pertaining to the three dimensions. Reliability results, on the other hand, were at 0.6 and above for all dimensions and measured elements.

• Journal of Digital Convergence
• /
• v.18 no.10
• /
• pp.147-162
• /
• 2020

The purpose of this study is to present practical improvement plans for policy fund support in national policy banks through an analysis of the efficiency of policy fund support. It targets small and medium-sized enterprises(SMEs) that received policy funding from national policy banks in '17 and '18 consecutively. As for the analysis method, characteristic analysis and corresponding sample T-test was performed. The analysis results are as follows. First, as a result of analyzing the characteristics of small and medium-sized enterprises, most of the financial funds were concentrated on the manufacturing industry. By region, the western region of Gyeonggi Province, by credit rating, was A grade, technology grade was T5, and the use of funds was mostly concentrated on facility funds. Second, as a result of efficiency analysis, profitability had a positive effect on total capital return, stability had a positive effect on interest compensation ratio, and activity had a positive effect on total capital turnover. In conclusion, it is expected to provide practical improvement plans to support policy funds to influence the growth and distribution of funds appropriate to the needs of SMEs.