• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.3
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• pp.383-392
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• 2015

In subsea tunnelling, prediction of the fractured zone (or water bearing zone) ahead of tunnel face saturated by seawater with high water pressure has been a key factor for safe construction. This study verified the feasibility of utilizing induced polarization (IP) survey at tunnel face for predicting the ground condition ahead of the subsea tunnel face. A pore model was proposed to compute chargeability in granular material, and the relationship correlating chargeability with the variables affecting the chargeability was derived from the model. Parametric study has been performed on the variables to figure out the most influential factors affecting the chargeability. The results of the parametric study show that the size of narrow pores ($r_1$) and the salinity of pore water are the most influential factors on chargeability. Laboratory tests were conducted on various types of ground condition by changing the salinity of pore water, the thickness of the fracture zone and the existence of gouge (weathered granite) within the joints of the fractured zone to figure out the effect of the ground characteristics on the IP phenomenon. Test results show that the chargeability of the fractured zone saturated by seawater increases if the joints in the fractured zone are filled with gouge since the infilled gouge will decrease the size of narrow pores ($r_1$).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.303-311
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• 2020

This study examines the effects of children's play activities through forest experience on their parents' expectation and multiple intelligence improvement. To achieve this, an empirical survey was conducted by applying a structural equation model to 152 parents with children. As a result, first, physical and cognitive factors were adopted, and social factors were rejected in the factors that influence the physical, social, and cognitive factors of children's forest experience play activities on parents' expectation of children's safety activities and concern about fine dust. Second, their physical, social and cognitive factors affected their sociality among sub-factors of multiple intelligence improvement. Their social and cognitive spontaneities significantly affected their sensitivity and creativity improvements. Third, parents' expectation did not appear to play a significant mediating role in the effect of play activity through forest experience on multiple intelligence improvement. This study has confirmed that their physical and cognitive factors of play activities through forest experience are directly affected by their parents' concern about fine dust and expectation of their safe activities, and has suggested that their sociality can be thoroughly learned through various educational programs in daycare centers, which is somewhat far from their parents' expectation of their play activities through forest experience.

• Journal of Korea Technology Innovation Society
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• v.18 no.3
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• pp.416-443
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• 2015

The resource-based view (RBV) explains that the competitive advantage is mainly based on the resources which have strategic characteristics. Therefore, finding, developing and maintaining strategically valuable resources has been one of main research topics and a starting point in the corporate strategy structure in RBV. In this regards, attempts to recognize strategically valuable resources have been one of crucial issues in RBV researches. Especially, Barney's VRIO has been widely used as a practical tool for finding strategically valuable resources. However, empirical studies on VRIO framework's effectiveness have not been sufficiently implemented, and there has been no proven relation among the components of the VRIO so far. This is mainly because the concepts or definitions on core components of the VRIO - Value, Rareness, Inimitability, and Organization - are too comprehensively explained and measurements of each component cannot be easily quantified. Considering these, this paper presents empirical results of the relation between VRIO components and competitive advantage, and tests effectiveness of VRIO Framework with utilizing sufficient technology evaluation cases and financial statements of 2,252 technology based SMEs in Korea. As a result, the components of the VRIO have a positive influence on competitive advantage. The attributes of strategic resources - Value, Rareness, and Inimitability - have a statistically meaningful positive effect on organization, while organization has a positive effect on the competitive advantage serving as a parameter between the attributes of strategic resources and competitive advantage.

• The Korean Journal of Pharmacology
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• v.29 no.2
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• pp.253-261
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• 1993

Possible changes in the role of insulin-sensitive cyclic nucleotide phosphodiesterase(PDE) in mediating the antilipolytic action of insulin were investigated in adipocytes from streptozotocin-induced diabetic rats. Isolated adipocytes prepared from epididymal adipose tissue were incubated, with or without insulin, at $37^{\circ}C$ for 15 min following pretreatment with various drugs or toxins, and three (plasma membranes, microsomal membranes, and cytosol) fractions prepared by differential centrifugation were then assayed for cAMP phosphodiesterase activity. The PDE activities only in the crude microsomal (P2) fractions were activated by insulin both in diabetic and control rats. The basal PDE activities in P2 fractions of adipocytes from diabetic rats were higher than those from control rats, although the maximal effects observed at 2 nM of insulin, $100\;{\mu}M$ of isoproterenol or the combination of both were not significantly different from each other. The insulin-stimulated PDE activities in P2 fractions of adipocytes from diabetic rats were not changed by PIA, a $A_{1}$ adenosine receptor agonist, whereas they were decreased to the basal PDE activities in those from control rats. In addition, the adipocytes from diabetic rats showed an increased sensitivity to pertussis toxin compared to those from controls. There were no differences between diabetic and control rats in the sensitivity of adipocytes to cholera toxin. These data indicate that the impaired signalling through inhibitory receptors such as adenosine receptors in adipocytes from streptozotocin-induced diabetes relates to the loss or the decreased function of $G_i$ proteins, and leads to the increased activity of the insulin-dependent PDE at the basal states.

• Tunnel and Underground Space
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• v.24 no.2
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• pp.155-165
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• 2014

Multiple thermal energy storage (TES) caverns can be used for storing thermal energy on a large scale and for a high-aspect-ratio heat storage design to provide good thermal performance. It may also be necessary to consider the use of multiple caverns with a reduced length when a single, long tunnel-shaped cavern is not suitable for connection to aboveground heat production and injection equipments. When using multiple TES caverns, the separation distance between the caverns is one of the significant factors that should be considered in the design of storage space, and the optimal separation distance should be determined based on a quantitative stability criterion. In this paper, we described a numerical approach for determining the optimal separation distance between multiple caverns for large-scale TES utilization. For reliable stability evaluation of multiple caverns, we employed a probabilistic method which can quantitatively take into account the uncertainty of input parameters by probability distributions, unlike conventional deterministic approaches. The present approach was applied to the design of a conceptual TES model to store hot water for district heating. The probabilistic stability results of this application demonstrated that the approach in our work can be effectively used as a decision-making tool to determine the optimal separation distance between multiple caverns. In addition, the probabilistic results were compared to those obtained through a deterministic analysis, and the comparison results suggested that care should taken in selecting the acceptable level of stability when using deterministic approaches.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.3
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• pp.48-62
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• 2018

In this study, landslide of debris flow occurred at 51 sites around Daeryounsan located in between Chuncheon-si and Hongcheon-gun during July in 2013 were investigated in field and behavior characteristics of debris flow were analyzed on the basis of records of rainfall and site investigation. According to debris flow types of channelized and hill slope, location and slope angle of initiation and deposit zone, and width and depth of erosion were investigated along entire runout of debris flow. DEM(Digital Elevation Model) of Daeryounsan was constructed with digital map of 1:5,000 scale. Land slide hazard was estimated using SINMAP(Stability INdex MAPping) and the predicted results were compared with field sites where debris flow occurred. As analyzed results, for hill slope type of debris flow, predicted sites were quite comparable to actual sites. On the other hand, for channelized type of debris flow, debris flow occurrence sites were predicted by using stability index associated with topographic wetness index. As analyzed results of 4 different conditions with the parameter T/R, Hydraulic transmissivity/Effective recharge rate, proposed by NRCS (Natual Resources Conservation Service), predicted results showed more or less different actual sites and the degree of hazard tended to increase with decrease of T/R value.

• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.5
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• pp.35-44
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• 2011

PGA (Peak Ground Acceleration) is the parameter which indicates the peak value for strong ground motion and is mainly due to the intensity of the seismic wave. Usually, seismic waves can consist of different characteristics and can have different effects on structures. Therefore, it may be undesirable that the effects of a seismic wave are evaluated only based on the PGA. In this study, time history analysis was executed with a single degree of freedom model for inelastic seismic analysis. The numerical model was assumed to be a perfect elasto-plastic model. Input accelerations were made with El Centro NS (1940), other earthquake records and artificial earthquakes. The displacement ductility demand and cumulative dissipated energy, which were calculated from other artificial earthquakes, were compared. As a result, different responses from other seismic waves which have the same PGA were identified. Therefore, an index which could reflect both seismic and structural characteristics is needed. The SI (Spectrum Intensity) scale which could be obtained from integration by parts of the velocity response spectrum could be an index reflecting the inelastic seismic response of structures. It can be possible to identify from correlation analysis among the SI scale, displacement ductility demand and cumulative dissipated energy that the SI scale is sufficient to be an index for the inelastic response of structures under seismic conditions.

• Journal of The Korean Association For Science Education
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• v.37 no.3
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• pp.417-427
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• 2017

Media is the medium that impart information beyond time and space. They refer to characters or images that serve as means to convey information. From old media such as newspapers and television to new media such as the internet and smart phones, media has developed cumulatively with the development of technology. The goal of media education is to develop the understanding of the properties of media, the ability of critical interpretation of media and selective acceptance. Furthermore it is to cultivate the ability to express meaning creatively and communicate through media. I carried out 'the research of Korean classroom instruction models based on media' with Korean language and social studies education researchers from July 2016 to December 2016. This study is a fundamental study of the project. Based on 58 research papers published between 2006 and 2016, research trends and factors were extracted through literature studies related to media-based science learning. The Result has shown that the studies related to media-based science learning is on the rise, and more than half of all researchers studied about elementary school students. The studies were divided into research on students, research on teachers and pre-service teachers, research on smart devices or media contents, and research on the development of digital textbooks. Among the four variables, there were many researches related to students' cognitive and affective development, and the development and application of media contents.

• International Commerce and Information Review
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• v.16 no.5
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• pp.343-359
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• 2014

This study investigates how cultural differences between countries affect bilateral trade volumes, using Hofstede's cultural index that reflects nations' cultural characteristics. Empirical analyses of the impacts of Hofstede's five cultural characteristics on bilateral trade volumes are conducted either in each separate equation or simultaneously. Bilateral trade data of OECD countries plus China as of year 2010 is used for regression analysis on gravity model. Regression results from individual equation for each cultural index variable show tthe smaller the index gaps of power distances and uncertainty avoidance among countries, the larger bilateral trade volumes. On the contrary, the larger the index gaps of long-term orientation among countries, the larger bilateral trade volumes. If five Hofstede cultural indexes are regressed in a single equation, however, only variables of power distance and long-term orientation are significant. The analysis largely confirms that bilateral trade among countries with similar culture have much potrential to grow. It implies that policy actions for cultural proximity are very important for furthering bilateral trade.

• Korean journal of communication and information
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• v.51
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• pp.5-25
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• 2010

The purpose of this research examined the relationship between the level of news usage on Influenza A(H1N1) and media users' behavioral intention toward health protection. Specifically, the study investigated causal relationships among exposure of media information on Influenza A(H1N1) as an independent variable, psychological protection motivation factors such as perceived severity, vulnerability, response efficacy, & self-efficacy as mediated variables and behavioral intention on personal and public health protection as dependent variables using structure equation model analysis. Self-reported questionnaires were administrated to 460 college students. The result indicated the followings. First, the level of news usage on Influenza A(H1N1) was not statistically significant on influencing behavioral intention toward personal and public health protection. Second, perceived severity, vulnerability, and self-efficacy were significant variables on behavioral intention toward personal health protection whereas perceived vulnerability and response efficacy were significant on public health protection. The function among factors in protection motivation theory is dependent upon whom protected from illness.