• Journal of the Korean Professional Engineers Association
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• v.44 no.2
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• pp.46-50
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• 2011

Wind energy, as an alternative to fossil fuels, is plentiful, renewable, widely distributed, clean, and produces no greenhouse gas emissions during operation. However, the construction of wind farms is not universally welcomed because of their visual impact, competing land use, comprising human health impacts, building and crop damage, loss of amenities and ecological impact, impact on wildlife, danger to birds, safety hazard, aesthetics and noise. Offshore wind power, in particular, offers a huge potential to generate clean energy. However, the envisaged massive expansion of wind farms in oceans is already causing severe environmental conflicts. Wind farms cause further harm to already threatened oceans. Wind power has negligible fuel costs, but a high capital cost. The expansion of climate-friendly wind energy use both onshore and offshore can only be successful it the legal and organizational conditions undergo some clear improvements.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.3
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• pp.51-58
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• 2008

Ninety five percent of the agricultural reservoirs were constructed by earth or rock. There are 18,000 agricultural dams and reservoirs in Korea. Therefore, it is easy to evaluate or identify their problems. Reservoirs should be repaired before too late. It is required to guarantee the proper functions of the existing agricultural dams and reservoirs in time to minimize the damage. In this study, in order to evaluate degradation of agricultural reservoir, grasps the safety of reservoir choosing for agriculture of 25 reservoirs which are distributed in Chungbuk region rural and analyzed using possibility as reservoir of agricultural usage. The degradation was evaluated by a compilation of the result where embankment and structure were separately handled, measured and then multiplied scores for each categories. By activating this research, current status of agricultural reservoir and degradation status will be easily measured. In addition, the research could be also used as a tool for an effective control or maintenance.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.10a
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• pp.249-257
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• 1996

Dynamic Analysis of Precast Concrete Large Panel Structures with Horizontal Joints The damage in precast large panel structures subjected to destructive earthquakes is generally localized in the joints. Particularly, the horizontal joints influence on the stability and integrity of the overall structure. In this research a dynamic analysis was carried out by the macro model that idealized the horizontal joints as inelastic-nonlinear spring systems. It is capable of simulating the behavior of precast concrete structures using the mathematical model. As a result of the dynamic parametric study for the case of 0.12g peak base accelerations, it is found that all joints behave elastically for sliding and opening and that all forces are well distributed without excessive local concentration on my horizontal joints.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.456-461
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• 2003

A fuel cell is an electrochemical device in which the energy of a chemical reaction is converted directly into electricity. By combining hydrogen fuel with oxygen from air, electricity is formed, without combustion of any form. Water and heat are the only by-products when hydrogen is used as the fuel source. Fuel cell stack consists of multi-layered unit cells. A unit cell consists of MEA and bipolar plates. The end plate of fuel cell stack should give a uniform distributed pressure to multi unit cell layers so as to reduce the contact resistance and to prevent the leakage of reactant gases and the damage of multi layer components. The current end plate is redundantly large and heavy. It makes the power per unit volume reduced. Topology optimization of end plate is conducted for mass reduction and enhancement of bending rigidity. The evaluation of the current design and the recommendation for the future design is remarked.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7505-7513
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• 2014

Several toxic substances have been detected in plants which are responsible for animal and human diseases. Bracken fern (Pteridium aquilinum) is one example, widely distributed in many parts of the world. It is known to cause cancer in humans and other animals. In fact, man can be directly or indirectly exposed to the danger by consuming fern, contaminated water, milk, meat, and spore inhalation. Experimental studies have shown an association between bracken exposure and gastric cancer, and research has shown genotoxic and cytotoxic effects in vitro. This paper describes and reviews toxic, carcinogenic, genotoxic/cytotoxic, and immunomodulatory effects of bracken and included possible toxic agents. The chemistry of Ptaquiloside (PT) reactions is emphasized, along with bracken problems in livestock, possible pathways of exposure in man, and control for human health.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.21-28
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• 2006

Structural health monitoring (SHM) is a new technology that will be increasingly applied at the industrial field as a potential approach to improve cost and convenience of structural inspection. Recently, the development of smart sensor is very active for real application. This study has focused on preparation and application study of SAL sensor. In order to detect elastic wave, smart piezoelectric sensor, SAL, is fabricated by using a piezoelectric element, shielding layer and protection layer. This protection layer plays an important role in a patched network of distributed piezoelectric sensor and shielding treatment. Four types of SAL sensor are designed/prepared/tested, and these details will be discussed in the paper. In this study, SAL sensor can be feasibly applied to perform structural health monitoring and to detect damage sources which result in elastic waves.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.271-276
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• 1996

Coolant flow distribution to the assemblies and core coolant/component temperatures should be determined in LMR core steady state thermal-hydraulic performance analysis. Sodium flow is distributed to core assemblies with the overall goal of equalizing the peak cladding midwall temperatures for the peak temperature pin of each pin bundle, thus pin cladding damage accrual and pin reliability. The flow orificing analysis for conceptual design will be performed with Excel spreadsheet program ORFCE which was set up and tested, using the calibration factors based on available analyses data. For the verification of this program, flow orificing calculation for the MDP 840MWth core was performed. The calculational results are satisfactory compared to those of CRIEPI calculation.

• Smart Structures and Systems
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• v.5 no.2
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• pp.139-152
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• 2009

Globally, civil infrastructures are deteriorating at an alarming rate caused by overuse, overloading, aging, damage or failure due to natural or man-made hazards. With such a vast network of deteriorating infrastructure, there is a growing interest in continuous monitoring technologies. In order to provide a true distributed sensor and control system for civil structures, we are developing a Structural Nervous System that mimics key attributes of a human nervous system. This nervous system is made up of building blocks that are designed based on mechanoreceptors as a fundamentally new approach for the development of a structural health monitoring and diagnostic system that utilizes the recently developed piezo-fibers capable of sensing and actuation. In particular, our research has been focused on producing a sensory nervous system for civil structures by using piezo-fibers as sensory receptors, nerve fibers, neuronal pools, and spinocervical tract to the nodal and central processing units. This paper presents up to date results of our research, including the design and analysis of the structural nervous system.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.584-590
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• 2009

One of the critical design problems involved in deep tunnelling in brittle rock, is the creation of surface spalling damage and breakouts. If weak fault zone is developed in deep tunnel, squeezing problem is added to the problems. According to the results of ground investigation in the study area, hard granitic rockmass and distinguished high angle fault zone are distributed on the tunnel level over 400m depth. To analyse the probability of brittle failure and squeezing, ground characterization with special lab. and field test were carried out. By the results, probability of brittle failures like spalling and rock burst is very low. But squeezing may be probable, if weak fault zone observed surface and drill core is extended to designed tunnel level.

• Korean journal of applied entomology
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• v.35 no.2
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• pp.137-139
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• 1996

The sycamore lace bug, Corythucha ciliata (Say), attacking a sycamore tree, Platatanus orientalis L., was first found in Korea, and was widely distributed in the central part of the country. The adult was milky white in color and 3.0-3.2 mm long, and the matured nymph was black. Heavily infested trees appear yellowish white as a result of feeding by the nymphs on the under surface of leaves.