• Korean Journal of Social Welfare Studies
• /
• v.44 no.2
• /
• pp.359-385
• /
• 2013

The study looked into the effect of internet utilization (utilization frequency and utilization ability in internet) on the life satisfaction level for the elderly in depth. In order to verify the correlation of two variables, a mediating model structured by ego integrity was used which gave out the Seoul welfare panel data created by Seoul welfare foundation in 2010. The total sample size was a group of 1862 elders aged over 60. When it came to our research methods, structured equation analysis was applied to verify the mediating effect and theoretical background. The findings are as follows: First, elderly's utilization frequency in internet is not an influencing factor to life satisfaction and elderly's utilization ability in internet is an influencing factor to life satisfaction. Second, the level of social activity did function as partial mediator on relationship between elderly's utilization ability in internet and life satisfaction. This study indicates theoretical and practical interventions to promote elderly's utilization in internet.

• International Journal of Air-Conditioning and Refrigeration
• /
• v.12 no.1
• /
• pp.1-9
• /
• 2004

The purpose of the present study is to examine the heat transport limitations in a screen mesh heat pipe for electronic cooling by theoretical analysis. Diameter of pipe was 6mm, and mesh numbers were 50, 100, 150, 200 and 250, and water was investigated as working fluid. According to the change of mesh number, wick layer, inclination and saturation temperature, the maximum heat transport limitations by capillary, entraintment, sonic and boiling were analyzed by a theoretical design method of heat pipe, including capillary pressure, pumping pressure, liquid friction coefficient in wick, vapor friction coefficient, etc. Based on the results, the capillary limitation in a small diameter of heat pipe is largely affected by mesh number and wick layer. Mesh number of 250 is desirable not to be used in pipe diameter of 6 mm, because capillary heat transport limitation decreases by the abrupt increase of liquid friction pressure due to the small liquid flow area. For the heat transport of 15 watt in 6mm diameter pipe, mesh number of 100 and one layer is an optimum wick condition, which thermal resistance is the smallest.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.32 no.3
• /
• pp.149-156
• /
• 2018

Traditional medicines (TM) in Korea, China, and Japan share most of the theories and therapeutic tools, but there are also differences due to their unique histories and cultures. Here, we aim to identify the differences in the utilization of TM theory between three countries by analyzing herb usage data in terms of the related traditional theories. Herb usage data of each country was collected from "Investigation of Korean medicine use and herbal medicine consumption survey" (Korea), "Analytical report on circulation of key Chinese medicinal materials" (China), and "Survey report on raw material crude drug usage" (Japan). Fifty five herbs with sixty features belonging to five theoretical categories (four properties, five tastes, targeting meridians, treatment strategies, and herbal parts) were selected and analyzed. Weight Sum Model (WSM) and Network-Based Group Features (NBGF) were used to compare the theoretical characteristics of TM between three countries. For the statistical evaluation, we developed and applied Herb Set Enrichment Analysis (HSEA) for WSM and NBGF results. HSEA for WSM results revealed the kidney meridian were targeted more in Korea than Japan, while the spleen meridian were targeted more in Japan than Korea. Herbs with sour taste were used more in Japan than China. HSEA for NBGF results found that NBGF including warm, neutral, sweet, and tonifying features were more dominant in Korea and than Japan, while NBGF including cold, bitter, heat-clearing features were more dominant in Japan than the others. These results suggest that TM in Korea, China, and Japan have unique aspects of practice patterns and theoretical utilization.

• Journal of Information Technology Applications and Management
• /
• v.15 no.3
• /
• pp.127-152
• /
• 2008

This study sought to explore how SMEs are utilizing EC. Drawing on existing research on IT and EC related field, this study presented the framework of EC utilization level and analyzed its affecting factors in the point of organizational perspectives; strategy and competency. The impact of EC utilization on firm performance was also examined by employing BSC. Structural equation model was applied to test the relationships among the theoretical constructs with data from 171 SMEs. The results showed that the rate of EC utilization in SMEs is growing quite rapidly. However, manufacturing related firms still remain at a lower level compared to service related firms. As for the two affecting factors of EC utilization level, it was found that the level of EC utilization appeared to be driven not by strategy but by competency. This result implicates that EC utilization in SMEs doesn't reach to strategic purpose yet, while it is dependent on firm's competency. As far as the impact of EC utilization on firm performance, the study showed that the level of EC utilization has significant relationship with all perspectives performance indicators of BSC. This study can provide the managers with current EC utilization pattern and the guidelines as to where to put the efforts in the EC utilization and how to get an effective EC utilization strategy in the future.

• Journal of Power Electronics
• /
• v.14 no.5
• /
• pp.815-826
• /
• 2014

An improved bridgeless interleaved boost power factor correction (PFC) rectifier to improve power efficiency and component utilization is proposed in this study. With combined conventional bridgeless PFC circuit and interleaved technology, the proposed rectifier consists of two interleaved and magnetic inter-coupling boost bridgeless converter cells. Each cell operates alternatively in the critical conduction mode, which can achieve the soft-switching characteristics of the switches and increase power capacity. Auxiliary blocking diodes are employed to eliminate undesired circulating loops and reduce current-sensing noise, which are among the serious drawbacks of a dual-boost PFC rectifier. Magnetic component utilization is improved by symmetrically coupling two inductors on a unique core, which can achieve independence from each other based on the auxiliary diodes. Through the interleaved approach, each switch can operate in the whole line cycle. A simple control scheme is employed in the circuit by using a conventional interleaved controller. The operation principle and theoretical analysis of the converter are presented. A 600 W experimental prototype is built to verify the theoretical analysis and feasibility of the proposed rectifier. System efficiency reaches 97.3% with low total harmonic distortion at full load.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.6 no.4
• /
• pp.989-1005
• /
• 2012

In this paper, throughput of IEEE 802.11 carrier-sense multiple access (CSMA) with collision-avoidance (CA) protocols in non-saturated traffic conditions is presented taking into account the impact of imperfect channel sensing. The imperfect channel sensing includes both missed-detection and false alarm and their impact on the utilization of IEEE 802.11 analyzed and expressed as a closed form. To include the imperfect channel sensing at the physical layer, we modified the state transition probabilities of well-known two state Markov process model. Simulation results closely match the theoretical expressions confirming the effectiveness of the proposed model. Based on both theoretical and simulated results, the choice of the best probability detection while maintaining probability of false alarm is less than 0.5 is a key factor for maximizing utilization of IEEE 802.11.

• The Mathematical Education
• /
• v.59 no.4
• /
• pp.405-420
• /
• 2020

There have been mixed reports about the idea of utilization of resources developed from one discipline across disciplinary areas. Grounded with the argument that critical thinking is not domain-specific (Mulnix, 2012; Vaughn, 2005), we developed a theoretical model of intellectual resources (IR) that students develop and use when learning and doing mathematics and science. The theoretical model shows that there are two parallel epistemic practices students engage in science and mathematics - searching for reasons and giving reasons (Bailin, 2002; 2007; Mulnix, 2012). Applying Confirmatory Factor Analysis and Structural Equation Model to the data of 9,300 fourth grade students' responses to standardized science and mathematics assessments, we verified the theoretical model empirically. Empirically, the theoretical model is verified in that fourth graders do use the two epistemic practices, and the development of parallel practices in science impacts the development of the two practices in mathematics: A fourth grader's ability to search for reasons in science affects his or her ability to search for reasons in mathematics, and the ability to give reasons in science affects the same ability use in mathematics. The findings indicate that educators need to open ideas of sharing development of epistemic practices across disciplines because students who developed intellectual resources can utilize these in other settings.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.8 no.3
• /
• pp.749-761
• /
• 2014

Improving spectrum utilization efficiency is a fundamental goal of dynamic spectrum access technology. The definition of spectrum holes determines how to detect and exploit them. Current definitions of spectrum holes are ineffective in exploiting spatial-temporal spectrum holes. In this paper, a novel definition of spectrum holes is proposed, in which throughput loss indicates the impact of secondary users on primary users. The definition specifies spectrum holes, unifies the impact of secondary users on primary users and is effective exploiting spatial-temporal spectrum holes. Theoretical analysis and numerical simulations show that the new definition proposed in this paper significantly improves the spectrum utilization efficiency.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.5
• /
• pp.1005-1010
• /
• 2011

The accidents caused by dielectric instability have been increasing in power grid. It is important to enhance the dielectric reliability of a high voltage apparatus to reduce the damage from electrical hazards. To develop an electrically reliable high voltage apparatus, the experimental study on the electrical breakdown field strength is indispensable, as well as theoretical approach. In this paper, the lightning impulse breakdown characteristics considering utilization factors are studied for the establishment of insulation design criteria of an high voltage apparatus. The utilization factors are represented as the ratio of mean electric field to maximum electric field. Dielectric experiments are performed by using several kinds of sphere-plane electrode systems made of stainless steel. As a result, it is found that dielectric characteristics are affected by not only maximum electric field intensity but also utilization factors of electrode systems. The results are expected to be applicable to designing the air-insulated high voltage apparatuses.

• Health Policy and Management
• /
• v.29 no.3
• /
• pp.288-302
• /
• 2019

Background: The one-person households (OPH) are rapidly increasing and vulnerable to socioeconomic and health problems. Because it is predicted to be inequitable to health care utilization, we would like to find out about the equity of health care utilization of the OPH by comparison with the multi-person households (MPH). Methods: This study followed the theoretical framework of Wagstaff and van Doorslaer (2000), O'Donnell and his colleagues (2008), where the horizontal inequity index is the difference between the concentration indices of actual health care utilization and health care needs. This study employed the 9th Korea Health Panel survey, and a total of 10,807 cases were analyzed. Health care needs were measured by age, sex, subjective health status, chronic disease count, Charlson's Comorbidity Index, limitation of activities, and disability. Results: Compared with the MPH, there were pro-poor inequities in hospitalization, emergency utilization, hospitalization out-of-pocket payments, and pro-rich inequities in outpatient out-of-pocket payments for the OPH. The decomposition of the concentration index revealed that chronic disease count made the largest contribution to socioeconomic inequality in outpatient utilization. Age, health insurance, economic activities, and subjective health status also proved more important contributors to inequality. The variables contributing to the hospitalization and emergency utilization inequity were age, education, Charlson's Comorbidity Index, marital status, and income. Conclusion: Because the OPH was more vulnerable to health problems than the MPH and there were pro-poor inequities in medical utilization, hospitalization, and emergency costs, it is necessary to develop a policy that can correct and improve the portion of high contribution to medical utilization of the OPH.