• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.10
• /
• pp.1881-1887
• /
• 2011

In this work the recyclable new polyethylene(PE) and polypropylene(PP), which are thermoplastic, have been investigated as the eco-friendly insulating candidates to replace the cross-linked polyethylene (XLPE). The temperature dependence of conductivities of these materials has been measured and its effects on electric field and space charge distribution in polymeric insulated power cable under temperature gradient have been calculated. It is shown that the sensitivity of conductivity to temperature change has more critical influence to determine the electric field distribution in the power cable than the absolute value of conductivity does and it can be said that the temperature dependence is one of most important factors for the power cable design.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2011.11a
• /
• pp.151-152
• /
• 2011

As recent construction projects aim to build higher and bigger buildings, lifting operation is getting increasingly important in construction sites. Accordingly, as tower cranes get higher and higher, disasters involving tower cranes are also on the rise. According to occupational incident statistics of the Korea Occupational Health & Safety Agency (KOHSA), most of such incidents occur in installation, dismantling and climbing phases of tower crane. Therefore, it is essential to develop preventative measures to secure safety of tower crane operations, with critical focus on installation, dismantling and climbing of tower crane. Hence, this research attempts to measure criticality of key risk factors in installation, dismantling and climbing phases of tower crane on construction site and propose necessary safety measures. As a result, conclusions herein will contribute to minimize disasters and incidents involving tower cranes in high-rise building construction sites.

• Carbon letters
• /
• v.2 no.1
• /
• pp.37-43
• /
• 2001

Mercury has been identified as a potential health and environmental hazardous material. Activated carbon adsorption offers promising potential for the control of mercury emissions, and sulfur impregnated (sulfurized) activated carbons has been shown to be an effective sorbent for the removal of vapor phase $Hg{\circ}$ from sources. In this work, vapor phase mercury adsorption by sulfur impregnated activated carbons were investigated. Sulfur impregnated activated carbons were made by variation of impregnation temperature, and the comparison of adsorption characteristics with commercial virgin and sulfurized carbons were made. Factors affecting the adsorption capacity of virgin and sulfurized activated carbons such as pore characteristics, functional groups and sulfur impregnation conditions were discussed. It was found that the sulfur allotropes plays a critical role in adsorption of mercury vapor by sulfurized activated carbons.

• Proceedings of the KSME Conference
• /
• 2001.11a
• /
• pp.533-538
• /
• 2001

This paper describes a combinational method to compute the global and local solutions of optimization problems. The present hybrid algorithm uses both a genetic algorithm and a local concentrate search algorithm (e. g simplex method). The hybrid algorithm is not only faster than the standard genetic algorithm but also supplies a more accurate solution. In addition, this algorithm can find the global and local optimum solutions. The present algorithm can be supplied to minimize the resonance response (Q factor) and to yield the critical speeds as far from the operating speed as possible. These factors play very important roles in designing a rotor-bearing system under the dynamic behavior constraint. In the present work, the shaft diameter, the bearing length, and clearance are used as the design variables.

• Journal of Contemporary Eastern Asia
• /
• v.15 no.1
• /
• pp.98-110
• /
• 2016

Building resilient community is often a complicated process to be gained by interorganizational collaboration. Since patterns of interorganizational relations among governments and sectors are constantly changing due to internal and external factors in the field of emergency management, understanding the dynamic nature of interorganizational collaboration is a critical step for improving a community’s ability to bounce back from a catastrophic event. From two theoretical perspectives, this research aims to examine the essential role of working across levels of governments and sectors in building resilient community by focusing on sources of community resiliency and a strong commitment. The empirical evidence highlights the importance of studying resilience as a way to understand the motivation and incentive for organizations to work jointly during emergency response. The study of organizational resilience also draws attention for the importance of various forms of interorganizational collaboration such as formal and informal relations. It also highlights how local organizations can utilize their relations to seek resources without necessarily jeopardizing their ability to perform their core organizational functions.

• Knowledge Management Research
• /
• v.9 no.1
• /
• pp.147-161
• /
• 2008

In the previous KM (Knowledge Management) studies, it has been repeatedly pointed that CoP (Community of Practice) should be used as a platform for boosting up corporate innovative activities. Despite this, it is very rare to find relevant literature in which real-world cases are introduced showing critical success factors, implemented strategies, and objective analysis of results. In this sense, main objective of this paper is very timely- to introduce a real-world CoP case in which POSCO, world-leading steel company, sorted out creative CoP strategies to nurture knowledge-sharing activities to solve various kinds of problems at hand, and maintain appropriate level of knowledge circulation throughout all the working units of company. In a nutshell, POSCO has been successful in any measure in utilizing the creative CoP activities as strategic means to change the paradigm of innovation and extract fruitful outcomes from integrating three important individual activities such as work, learning, and innovation.

• Mycobiology
• /
• v.39 no.3
• /
• pp.143-150
• /
• 2011

The basidiomycete fungus Cryptococcus neoformans is an important pathogen of immunocompromised people. The ability of the fungus to sense its environment is critical for proliferation and the generation of infectious propagules, as well as for adaptation to the mammalian host during infection. The conserved cAMP/protein kinase A pathway makes an important contribution to sensing, as demonstrated by the phenotypes of mutants with pathway defects. These phenotypes include loss of the ability to mate and to elaborate the key virulence factors capsule and melanin. This review summarizes recent work that reveals new targets of the pathway, new phenotypic consequences of signaling defects, and a more detailed understanding of connections with other aspects of cryptococcal biology including iron regulation, pH sensing, and stress.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.10b
• /
• pp.922-927
• /
• 1998

Pipe cooling has been popularly used in the mass concreting work to reduce temperature of the structure since it is known to be the easiest way to apply and has been the customary usage. But wrong application of the system results in the harmful effect on the structure by crack formation due to thermal shocks and improper cooling schemes. Thus, this study aims at the suppling of effective cooling methods through parametric study. For this, circulating method, velocity of water supply and circulating duration were selected as critical factors affecting the effectiveness of cooling system. As a results of thermal analysis, it was found that too much thermal gradient in the vicinity of the pipe creates localized radial or circumferential cracks. The duration of circulating cooling may be recommended to be as short as several days which may safely reduce the concrete temperature to below a final stable value. It was also found that pipe cooling is more effective to decrease the degree external restraints than internal one.

• Proceedings of the Safety Management and Science Conference
• /
• 2007.04a
• /
• pp.73-80
• /
• 2007

Recently, the strategy of the age of limitless competition for existence of manufacturing company appears for the enhancement of productivity through the automatic system, the reduction for the cost for standardization and the decision making process for the information system. Especially the critical success factors in manufacturing company can be summarized for the establishment of production visibility through the production management, material & work-in-process management, the establish of the flexible manufacturing system for the changed order priority and the establish of the quality system for improvement of product and process quality. The existing production management systems supply only simple information about production results on real time, can delay quick decision making. And it can prevent acquiring the information about various customer needs and the communication problems with other systems. In this paper, it will show MES system, a solution for the problems of existing production management systems. And through a case study of D company, it will reveal improvement effect on shipment error using MES system and economic analysis for MES itself.

• Journal of Agricultural Extension & Community Development
• /
• v.1 no.1
• /
• pp.57-65
• /
• 1994

This study undertakes a critical survey of literatures on the nest development in agricultural extension system; T&V(Traininig and Visit Extension), FSR&E(Fanning Systems Research and Extension), and FF(Farmer First). The study compares the three extension systems in their establishment, objectives, charactersistics, and methods. to find the minor factors for the betterment of agricultural extension system. Those are; 1) client-oriented program, 2) educational service, 3) comprehensive goal and work, 4) benefit to wide range of customers, 5) democratic program, 6) participatory approach, 7) four based experiment, 8) linkages among participants, 9) specialization of extensionists, 10) autonomy of extension offices, 11) humanstic program.