• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.11
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• pp.5400-5418
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• 2016

Femtocells are envisioned as a key solution to embrace the ever-increasing high data rate and thus are extensively deployed. However, the dense and random deployments of femtocell access points (FAPs) induce severe intercell inference that in turn may degrade the performance of spectral efficiency. Hence, unrestrained proliferation of FAPs may not acquire a net throughput gain. Besides, given that numerous FAPs deployed in ultra-dense networks (UDNs) lead to significant energy consumption, the amount of FAPs deployed is worthy of more considerations. Nevertheless, little existing works present an analytical result regarding the optimal FAP density for a given User Equipment (UE) density. This paper explores the realistic scenario of randomly distributed FAPs in UDN and derives the coverage probability via Stochastic Geometry. From the analytical results, coverage probability is strictly increasing as the FAP-to-UE ratio increases, yet the growing rate of coverage probability decreases as the ratio grows. Therefore, we can consider a specific FAP-to-UE ratio as the point where further increasing the ratio is not cost-effective with regards to the requirements of communication systems. To reach the optimal FAP density, we can deploy FAPs in line with peak traffic and randomly switch off FAPs to keep the optimal ratio during off-peak hours. Furthermore, considering the unbalanced nature of traffic demands in the temporal and spatial domain, dynamically and carefully choosing the locations of active FAPs would provide advantages over randomization. Besides, with a huge FAP density in UDN, we have more potential choices for the locations of active FAPs and this adds to the demand for a strategic sleeping policy.

• Korean Journal of Construction Engineering and Management
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• v.8 no.5
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• pp.119-131
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• 2007

Design build (DB) is a construction project delivery system which has become one of the favored ones and the growth of DB by the public agencies has been steadily increasing. DB can be viewed as an evolutionary project delivery system, since DB project team members collaborate on work with each other, keep seeking cost effective and innovative alternatives that meet the construction needs of the project. Thus DB outperformed others in delivery speed, cost saving, and turnover quality. In Korea, DB projects likewise have steadily increased that it is needed to analyze characteristics of DB delivery system in Korea. For that purpose, this research would offer an analysis of characteristics of DB delivery system in Korea using system dynamics model with investigating the public market trend, comparing DB performance to DBB, and analyzing questionnaire survey.

• Microbiology and Biotechnology Letters
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• v.38 no.1
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• pp.7-12
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• 2010

The biochemical study of sugar uptake in yeasts started five decades ago and led to the early production of abundant kinetic and mechanistic data. However, the first accurate overview of the underlying sugar transporter genes was obtained relatively late, due mainly to the genetic complexity of hexose uptake in the model yeast, Saccharomyces cerevisiae. The genomic era generated in turn a massive amount of information, allowing the identification of a multitude of putative sugar transporter and sensor-encoding genes in yeast genomes, many of which are phylogenetically related. This review aims to briefly summarize our current knowledges on the biochemical and molecular features of the transporters of pentoses in yeasts, when possible establishing links between previous kinetic studies and genomic data currently available. Emphasis is given to recent developments concerning the identification of D-xylose transporter genes, which are thought to be key players in the optimization of S. cerevisiae for bioethanol production from lignocellulose hydrolysates.

• Journal of Digital Convergence
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• v.15 no.1
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• pp.117-127
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• 2017

Even well trained personnel may fall victim to panic, and a wrong assessment of the situation can turn a small accident into a huge disaster. At the disaster site, the event is commonly broadcasted in real time and is unfiltered. Thus, the commander of the site must be able to accurately assess the scene while not missing out on key considerations. Despite the necessity of good situational assessment, there is barely any research on this topic. This study utilizes METT-TC(Mission, Enemy, Troops, Terrain and weather, Time available, and Civil considerations) which is used by militaries to assess combat situations, and proposes MORT-TAC(Mission, Object, Resources available, Terrain and weather, Time available, Ability, and Civil considerations) as factors to consider in effectively controlling the disaster site. The standard model is used for assessing disaster scenes by applying the Delphi analytical method on each sub-factor of MORT-TAC.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.255-263
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• 2017

Recently, cause marketing is more focused as one of key brand positioning strategies, which in turn leads that more companies are interested in cause marketing. In this study, we focused on two different types of cause marketing, named as public-volunteered cause marketing and corporate-driven cause marketing. A field study using an actual brand explored the effect of cause marketing type and brand authenticity on purchase intention toward the target brand. Moreover, we examined the moderation and moderated mediation of brand awareness. As our results showed, the corporate-driven cause marketing had a positive impact both on brand authenticity and purchase intention in the low (vs. high) brand awareness condition. However, the effect of public-volunteered marketing on purchase intention and brand authenticity did not vary depending on brand awareness. To increase the effectiveness of the cause marketing, the results suggest that the public-volunteered cause marketing would be more effective than the corporate-driven cause marketing.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.05a
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• pp.25-35
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• 2002

Transcription factor Nrf2 is essential for the antioxidant responsive element (ARE)-mediated induction of phase II detoxifying and oxidative stress enzyme genes. Detailed analysis of differential Nrf2 activity displayed in transfected cell lines ultimately led to the identification of a new protein, which we named Keap1, that suppresses Nrf2 transcriptional activity by specific binding to its evolutionarily conserved amino-terminal regulatory domain. The closest homolog of Keap1 is a Drosophila actin-binding protein called Kelch, implying that Keap1 might be a Nrf2 cytoplasmic effector. We then showed that electrophilic agents antagonize Keap1 inhibition of Nrf2 activity in vivo, allowing Nrf2 to traverse from the cytoplasm to the nucleus and potentiate the ARE response. We postulate that Keap1 and Nrf2 constitute a crucial cellular sensor for oxidative stress, and together mediate a key step in the signaling pathway that leads to transcriptional activation by this novel Nrf2 nuclear shuttling mechanism. The activation of Nrf2 leads in turn to the induction of phase II enzyme and antioxidative stress genes in response to electrophiles and reactive oxygen species.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.108-113
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• 2004

Marinas are often located in prime port side locations. hi Korea these locations are already developed and reclamation of the existing properties poses many difficulties and financial overhead. Also, to develop a standard marina in Korea with tide ranges up to 6 meters would require considerable dredging and reclamation works needing long lead times and large SOC costs. The Ocean Space's floating marina system is an independent offshore floating static level system that does not require fixed location breakwaters. The entire marina floats with the tide giving a calm consistent berthing condition for vessels irrespective of the surrounding tide and weather conditions. The floating marina system provides also for all of functions needed to marina comprising a breakwater to protect the vessels, the pontoon system to house the vessels, a dub house and retail tourism precinct, fuel reservoir and associated support facilities in a turn key self contained unit. The modular nature of the system will mean that initial demand can be met with simple units and then further modules can be added quite easily without the related expansion difficulties or infrastructure. This paper contains the main characteristics of the floating marina system and tire design process of the structure. The mooring, motion & stability analysis, the overall & local structural design and the mooring & anchor system design are introduced in this paper.

• Korean Journal of Construction Engineering and Management
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• v.13 no.5
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• pp.12-24
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• 2012

The Risks in undertaking a construction project comes from many sources and often involves many participants in the project. This study has identified various kinds of risks, assessed the risk factors quantitatively and suggested risk management method for response pertinent in Design Build(Turn Key)type of projects in Korean context. A questionnaire was designed comprising of 145 possible risks in all types of construction projects. The population from owner, consultant and contractor groups was asked to indicate the risks applicable in DB projects. 25 numbers of critical risks in DB projects were identified and further analyzed for reveling inherent relationship between them through factor analysis. Factor analysis revealed 8 risk factors in DB projects. Construction site related, contract related and design related risk factor consisted about 72% of total risk weight. It has been found out about 6%, while considering the mutual dependency, it is about 10% of total cost of DB project. Therefore, It is suggested that 6% to 10% of construction amount as contingency has to be made provision for risk responses in the DB projects.

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.1951-1957
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• 2007

A new synthetic strategy based on the acid-base catalyzed sol-gel method was developed for the preparation of a series of mesoporous TiO2 nanoparticles. A key feature of the method involves a gradual change in pH (0.8- 9) during the sol-gel transition, which guarantees easy introduction of mesoporosity without relying on the well-established sonochemical or template approach. In addition, this method leads to the exclusive formation of the anatase phase stable enough to the calcination temperature up to 600 oC. The physicochemical properties of the particles in the series were characterized by various spectroscopic and analytical techniques such as wide-angle XRD, SAXRD, BET surface area, FE-SEM, TEM, FT-IR, TGA, and XPS. The photocatalytic efficiency of these materials was investigated for the oxidation of toluene under UV-irradiation. All but T-ad in the series exhibited high photocatalytic activity pushing the reaction into completion within 3 h. The reaction followed the first order kinetics, and the rate reaches as high as 3.9 × 10?2/min which exceeds the one with the commercially available Degussa P-25 by a factor of 3.2. When comparison is made among the catalysts, the reactivity increases with increase in the calcination temperature which in turn increases the crystallinity of the anatase phase, thus revealing the following rate orders: T-3 < T-4 < T-5 < T-6.

• Journal of Korea Society of Industrial Information Systems
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• v.9 no.1
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• pp.69-76
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• 2004

Recently, smart cards with multi-applications loaded are becoming popular owing to many advantages. As many casual users would like to reduce the number of plastic cards, and card issuers want to upgrade the existing applications or add the new applications, and developers wish to reduce the development turn-around time, multi-applications smart cards are becoming important. In addition, many advantages exist between the business partners as smart card applications can share critical information. New operating systems such as JavaCard and MULTOS are suggested for the multi-applications smart card service recently. In this paper, after we review the principles of operations of smart card, we propose the various security mechanisms for the multi-application JavaCard service environment, which is becoming de facto standard in the industry.