• Asian Journal of Turfgrass Science
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• v.24 no.2
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• pp.182-190
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• 2010

This study was conducted to know the insect fauna on the 5 green Parks areas of Daegu Metropolitan city. Materials were collected by net sweeping and pitfall trap of cup. As the result, 100 species of 93 genera belonging to 61 families in 9 orders were surveyed, among them, Yeonam Park showed highest insect occurrence as 61 species belonging to 35 families of 8 orders. The other side, lowest site was Gukchae-Bosang memorial Park as 2 species from 2 orders. There was more species in broad-leaf tree area than mixture area of broadleaf and needle-leaf trees. Turf grass areas in the Parks showed low insect diversities.

• Journal of the Korean Society of Combustion
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• v.14 no.1
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• pp.31-38
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• 2009

The effects of acoustic excitation of coaxial air on mixing enhancement and reduction of nitrogen oxides (NOx) emission were investigated. A compression driver was attached to the coaxial air supply tube to impose excitation. Measurements of NOx emission with frequency sweeping were performed to observe the trend of NOx emission according to the fuel and air flow conditions and to inquire about the effective excitation frequency for reducing NOx. Then, Schlieren photographs were taken to visualize the flow field and to study the effect of excitation. In addition, phase-locked particle image velocimetry (PIV) was performed to acquire velocity field for each case and to investigate the effect of vortices more clearly. Direct photographs and OH chemiluminescence photographs were taken to study the variation of flame length and reaction zone. It was found that acoustic forcing frequencies close to the resonance frequencies of coaxial air supply tube could reduce NOx emission. This NOx reduction was influenced by mixing enhancement due to large-scale vortices formed by fluctuation of coaxial air jet velocity.

• Korean Journal of Occupational Health Nursing
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• v.20 no.2
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• pp.172-184
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• 2011

Purpose: The aim of this study is to identify the characteristics of occupational accidents by work type among municipal sanitation workers. Methods: The original data of occupational accidents in 2009 by Korea Occupational Safety & Health Agency were analyzed by frequency and percentage using the SAS Version 9.1. Results: The types of occupational accident were as follows: slips and trips, falls, musculoskeletal disorders, traffic accident, collision, amputation, cut & puncture, crush injuries, strenuous movement and drop/fly. Slips and trips occurred most frequently in domestic waste collection and street sweeping. The traffic accident showed the highest incidence in food waste collection. Falls occurred most frequently in recycling waste collection. Musculoskeletal disorders showed the highest incidence in large waste collection. Conclusion: Depending on the work type, types of occupational accident were different. The results of this study can provide the information for the development of the occupational accident prevention programs of municipal sanitation workers.

• International Commerce and Information Review
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• v.4 no.2
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• pp.131-153
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• 2002

An information technology revolution is sweeping the world driven by digitalization and tremendous popularity of the Internet. Electronic commerce and trade is the mainstream of this trend, and realization of a cyberspace without physical, spatial, and time restraints has led radical structural changes in international trade. Northeast Asia including Korea, China and Japan is becoming more important as a core economic region in terms of economic growth, intra-regional trade in particular. The introduction to electronic trade system and networks would playa vital role in speeding up trade of commodities, service and information etc. Therefore the study aims to examine a scheme to facilitate international trade in Northeast Asia by establishing information infrastructures. The study begins with reviewing current situation in information infrastructure such as the number of PC, utilization ratio of internet, information network, volume of electronic commerce. It is analyzed that what kinds of obstacles to facilitating electronic trade in Northeast Asian countries in terms of physical infrastructure, institutions, regulations, technologies regarding information exchange among countries. Finally this study presents some suggestions in order to remove the problems currently existed in vitalizing electronic trade.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.5
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• pp.845-853
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• 2009

This study recognize the problems about the High-speed IT building certification system and the technical standards of telecommunication facility, broadcasting public receiving facility including Home-network facility which are installed at apartments for the successful building of the Ubiquitous city that the government is driving and suggested a sweeping change of the housing law interrelated for making up a housing efficiency grade-display system and systematizing the maintenance by solutions. Also, presented the integrate-construction model designs separately of the residential IT line about the buildings applied to technical standards, the building acquired second grade below of High-speed IT building and the building when the above solutions get to he systematized.

• Journal of Information Technology Applications and Management
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• v.17 no.4
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• pp.57-82
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• 2010

Many companies today use information systems to maintain competitive advantage and to give immediate responses to customer requests. Over time, however, many of these companies failed to make the most of such information systems because the users stopped utilizing the system. While many reasons offer explanations to the phenomenon, this study analyzes how usage intention of information system can be enhanced by changing the environment and usefulness of the system from the user's perspective. Active and wide-ranging researches using the Technology Acceptance Model (TAM) have been carried out on an individual's tendency to using new technology. But, many of the studies remain focused on improving user intention by enhancing the ease of use and usefulness of the system under PC applications or Enterprise applications. The personalized intranet system is not only bringing about sweeping changes to a company's information systems environment but also providing users with freedom to design their own working environment, personalization, to Corporate Information Systems (CIS). Results from empirical tests on intranet systems verify that through personalization, a more voluntary information system environment can be created and that by increasing the ease of use and usefulness of the system, users can become more favorable to accepting new technologies and ultimately result in improved usage intention. This study suggests personalization variables and model for implementing a voluntary CIS for information system developers.

• Journal of Ecology and Environment
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• v.29 no.2
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• pp.125-141
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• 2006

Insect fauna in adjacent areas of Demilitarized Zone (DMZ) in Korea was surveyed seasonally in $2001{\sim}2003$. The survey area was divided into 3 regions (eastern mountain, middle inland, and western coastal regions) in accordance with administrative districts and topography. Sampling methods such as sweeping, sieving, beating, brushing and suction were used depending on the environmental and military conditions. Total 361 genera and 437 species of 116 families belonging to 14 orders were identified. Among these, 46 species were new to insect fauna of DMZ areas. Species richness was the highest in the eastern mountain region. Numbers of habitat-common and -specific species were 96 (22%) and 195 (47.2%), respectively. The insect species community similarity was highest (0.64) between eastern mountain region and western coastal region. Insect orders showing high species richness were Coleoptera (38.9%), Lepidoptera (19.2%), Orthoptera (9.4%), and Hemiptera (9.2%). These results will be useful information for study of history on the change of insect fauna and future conservation in DMZ areas.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.1 s.244
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• pp.74-81
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• 2006

Experiments to measure the pool boiling heat transfer on the micro-fin surfaces were performed with PF5060. The effects of various orientation and subcooling of heat surface on pool boiling performance were investigated under various heat-flux conditions for plain and micro-fin surfaces. The comparison between the results of this study and those of previous work shows a similar trend at the same conditions. From the results, it is proved that nucleate boiling performance is strongly dependent on the orientation, the micro-fin structure and the subcooling of heat surface. The heat flux on the surface with orientation angles of $45^{\circ}$ and $90^{\circ}$ was larger than that on horizontal surface(${\theta}=0^{\circ}$) at same wall superheat because of the effect of bubble sweeping. The nucleate boiling performance of micro-fin surfaces is enhanced by decreasing the fin size(WxL) and the pitch, respectively. The subcooling makes nucleate boiling performance lower for both micro-fin and plain surfaces.

• ALGAE
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• v.22 no.2
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• pp.141-146
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• 2007

Seagrass bed is an important component in coastal and estuarine ecosystems, providing food and habitats to a wide variety of marine organisms. Recently, seagrass coverage has declined significantly due to anthropogenic impacts such as cultural eutrophication and reclamation, and thus efforts are under way to prevent further losses and restore disturbed seagrass habitats worldwide. Seagrass transplantation techniques for habitat restoration include vegetative and seed-based methods. Seagrass seeds can be collected easily, and sowing seeds is an economically effective method for large-scale restoration. However, large numbers of seed can be lost by seed predation and physical disturbance in the planting areas. In the present study, Zostera marina seeds were coated with loess to reduce seed loss by predation and sweeping away by the water currents, and germination rates of coated seeds and seedling growth were examined to assess the feasibility of the seed-coating method for large-scale restoration. Germination rate of the coated seeds with loess was significantly higher than that of the uncoated seeds. Additionally, seedling growths were not significantly different between the coated and the uncoated seeds. These results suggest that coating of eelgrass seeds with loess enhances success of seed germintion with no harmful effects on seedling growth. Therefore, the seed coating method using loess may be an effective and applicable seedbased transplanting technique for large-scale restoration.

• Smart Structures and Systems
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• v.25 no.5
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• pp.543-557
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• 2020

This paper presents a series of experimental and numerical investigations on a vertical isolation system with quasi-zero stiffness (QZS) property. The isolation system comprises a linear helical spring and disk spring. The disk spring is designed to provide variable stiffness to the system. Orthogonal static tests with different design parameters are conducted to verify the mathematical and mechanical models of the isolation system. The deviations between theoretical and test results influenced by the design parameters are summarized. Then, the dynamic tests for the systems with different under-load degrees are performed, including the fast sweeping tests, harmonic excitation tests, and half-sine impact tests. The displacement transmissibility, vibration reduction rate, and free vibration response are calculated. Based on the test results, the variation of the transmission rule is evaluated and the damping magnitudes and types are identified. In addition, the relevant numerical time history responses are calculated considering the nonlinear behavior of the system. The results indicate that the QZS isolation system has a satisfactory isolation effect, while a higher damping level can potentially promote the isolation performance in the low-frequency range. It is also proved that the numerical calculation method accurately predicts the transmission character of the isolation system.