• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.5
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• pp.14-20
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• 2006

In recent year, as the robot technology is developed, the researches on the artificial muscle actuator that enables robot to move dexterously like biological organ become active. Actuators are key technologies underpinning robotics. Breakthroughs in actuator technology, particular in terms of power-to-weight ratio, or energy-density, will have significant impacts upon the design and control of robotic system. In this paper, a new approach to design and control of shape memory alloy(SMA) actuator is presented to drive the robot hand. SMA wire is divided into many segments and their thermal states of the SMA are controlled individually in a binary manner. This control manner will reduce the hysteresis that the SMA material has and it becomes the fundamental technology to develop the anthropomorphic robot hand. In this paper, the mechanism In the digital step motor of the shape memory alloy that is driven by the segmented binary control, which is a new control technique, is studied. This SMA digital step actuator applies for the robot hand and the driving mechanism of the robot hand is investigated.

• Journal of Biomedical Engineering Research
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• v.28 no.4
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• pp.577-584
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• 2007

Uroflowmetry is non-invasive and easily performed to diagnose benign prostatic hypertrophy(BPH) frequent in aged men. Weight change during urination is usually measured to estimate the urinary flow rate by a load cell, but sensitive to any impacts against the bottom of the container, leading to unnecessary noise generation. Moreover, load cells are relatively expensive raising the production cost. The present study proposed a new technique, measuring hydraulic pressure on the bottom of the urine container to evaluate the urinary volume. Low cost pressure transducer enabled almost perfectly linear relationship between the urine volume and the hydraulic pressure. During both the simulated and human urination experiments, variance of the pressure signal was more than 50% smaller than the weight signal acquired by a load cell, which demonstrated that the impact noise was decreased to a great degree by pressure compared to weight measurement.

• Water Engineering Research
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• v.5 no.3
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• pp.147-156
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• 2004

Recently, the population growth, industrial and agricultural development are rapidly undergoing in the Lower Rio Grande Valley (LRGV) in Texas. The Lower Rio Grande Valley (LRGV) composed of the 4 counties and three of them are interesting for Non-point and point source pollutant modeling: Starr, Cameron, and Hidalgo. Especially, the LRGV is an intensively irrigation region, and Texas A&M University Agriculture Program and the New Mexico State University College of Agriculture applied irrigation district program (Guy Fipps and Craig Pope, 1998), projects in GIS and Hydrology based agricultural water management systems and assessment of prioritized protecting stream network, water quality and rehabilitation based on water saving potential in Rio Grande River. In the LRGV region, where point and non-point sources of pollution may be a big concern, because increasing fertilizers and pesticides use and population cause. This project objective seeks to determine the accumulation of non-point and point source and discuss the main impacts of agriculture and environmental concern with water quality related to pesticides, fertilizer, and nutrients within LRGV region. The GIS technique is widely used and developed for the assessment of non-point source pollution in LRGV region. This project shows the losses in kg/$km^2$/year of BOD (Biological Oxygen Demand), TN (total Nitrogen) and TP (total phosphorus) in the runoff from the surface of LRGV.

• Journal of Ecology and Environment
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• v.31 no.4
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• pp.277-290
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• 2008

In the past two decades Mikania micrantha Kunth, a climbing plant species originating from tropical America, has spread across Taiwan. It can now be found frequently in the lowlands and lower mountain areas up to 1,000 m a.s.l. in the centre and south of the island. Mikania micrantha is considered a problematic invasive alien plant species which is said to cause economical as well as environmental damage. This study investigated the ecological site characteristics of M. micrantha in Taiwan. 112 vegetation surveys were carried out in habitats where the alien plant was present. A comparison between sites with a high and a low abundance was carried out in order to assess which factors especially influence the extensive spread of the plant. Furthermore, the influence of disturbances was examined. Results showed that Mikania micrantha grows very dense in habitats which are characterized by good light conditions combined with vertical structures, such as trees. Results revealed that this invader occurs most frequently in agricultural fallows and wastelands, but it could hardly be found in the intensively managed plantations in the investigation area. Results provide great evidence that the plant is strongly influenced by disturbances, but only if impacts occur rarely.

• Journal of Ecology and Environment
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• v.35 no.2
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• pp.61-71
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• 2012

Recent conditions in North Sulawesi Province (NSP) have become favorable for the development of tourism. In this paper, we present the recent status of biodiversity and tourism in NSP as a basic consideration towards integrative biodiversity conservation strategy. Overall, biological accounts suggest that NSP is important for the world biodiversity conservation program. NSP's biodiversity makes the area a major nature-based tourism (ecotourism) site in the world. Development of diverse tourism programs in NSP has provided new opportunities for balancing development and conservation of regional ecosystems. However, the excessive tourism growth in some particular areas in NSP has been identified as the primary factor of environmental degradation. Nowadays, biodiversity of North Sulawesi regions are suffering from the number of tourist impacts and facilities. Based on those conditions, tourism planning and development in NSP is needed to formulate a proper strategy to protect the ecosystem and biodiversity from degradation and extinction. This will be a new challenge of sustainable island tourism development and biodiversity conservation in NSP.

• Journal of Plant Biotechnology
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• v.42 no.3
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• pp.265-270
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• 2015

The roots of Codonopsis lanceolata (Campanulaceae) contain several kinds of triterpenoid saponin with high medicinal values, which have been used in traditional medicines. This study investigates the impacts of methyl jasmonate (MeJA) - adding time on the saponin synthesis and the hairy root growth of C. lanceolata. A significant decrease in major saponin (lancemaside of three kinds) content of hairy roots was observed with MeJA treatments. Contents of lancemaside A, B and E decreased about 15% more than non-treated hairy roots. In contrast, minor saponin (foetidissimoside A and aster saponin Hb) accumulation was about 15% higher than the non-treated hairy roots. These results suggest that MeJA treatment could be used in the production of teriterpene saponins.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.1
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• pp.97-109
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• 2004

The disposal of stormwater is one of the major problems in urban water management. One method of reducing peak runoff rates and other detrimental impacts of stormwater is detention storage. Detention ponds as a water quality control alternatives have been investigated by a number of researchers. Recognizing multiple roles such as flood peak attenuation, pollution removal and aesthetic enhancement, the design and management of detentions ponds deserve more research. The purpose of this research is to establish design criteria wet detention ponds to improve water quality. Water quality in detention pond discharge might be improve with physical, chemical and biological alterations. Physical alteration was focused in this study. There are several methods for estimating the suspended solid control capability of wet detention ponds. Existing models of suspended solids removal are based on sedimentation and gravity settling theory. The pollutant trap efficiency of pond is a function of several interrelating factors. Detention time is the most important factor, because it determine gravity settling quantities of pollutants. Desirable modification of physical factors for improvement of water quality in wet detention ponds are volume ratio, area ratio, length to width ratio, depth, out let location, bottom soil type. In order to apply design procedure in actual site, Namak new town development area was selected.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.3
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• pp.13-24
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• 2013

Agriculture is affected directly by climate conditions and changes, and it is necessary to understand the impact of climate change on agricultural reservoirs which are the main water resources for paddy fields in Korea. This study aimed to evaluate the impact of climate change on the anti-drought capacity including water supply capability (WSC) and drought response ability (DRA) of agricultural reservoirs based on RCP (Representative Concentration Pathway) 4.5 and 8.5 scenarios of CanESM2 (The Second Generation Earth System Model) provided by CCCma (Canadian Center for Climate Modeling and Analysis). The WSC and DRA were estimated using frequency analysis and runs theory. The six reservoirs (Yooshin, Nogok, Kumsung, Songgok, Gapyung, Seoma) were selected considering geographical characteristics and design criteria of reservoir capacity. In case of Seoma reservoir, more than 10 year drought return period (DRP), the variation of the WSC was estimated larger than the others. In case of Yooshin reservior (2~5 DRP) DRC was decreased in 2025s under RCP8.5. These results could be utilized for agricultural reservoirs management and future design criteria considering climate change impacts on paddy irrigation.

• Korean Journal of Ecology and Environment
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• v.43 no.4
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• pp.453-458
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• 2010

DOC (Dissolved Organic Carbon) is an operational terminology for organic carbon molecules dissolved in natural waters. DOC has been studied by ecologists extensively, because it plays a key role in various ecological functions such as substrates for secondary production and the carbon cycle. DOC also represents a substrate for microbial growth within potable water distribution systems, and can react with disinfectants (e.g., chloride) to form harmful disinfection by-products. In addition, residual DOC may carry with it organically bound toxic heavy metals. DOC in aquatic ecosystems may ultimately be transported to the oceans, or released back to the atmosphere by heterotrophic respiration, which can accelerate global climate change. There is evidence that DOC concentrations in aquatic ecosystems are increasing in many regions of the world including Europe, North America, and even in Korea. Land use changes, elevated temperature, elevated $CO_2$, recovery from acidification, and nitrogen deposition have been proposed as mechanisms for the trend. However, the key driving mechanism is yet to be conclusively determined. We propose that more extensive and longer-term observations, research of chemical properties of DOC, impacts of elevated DOC on environmental issues and interdisciplinary approaches are warranted as future studies to fill the gaps in our knowledge about DOC dynamics.

• Journal of Marine Bioscience and Biotechnology
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• v.6 no.1
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• pp.17-25
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• 2014

Periodically, harmful algal blooms (HABs) have occurred, with impacts on various areas including public health, tourism, and aquatic ecosystems, especially aquacultured and caged fisheries. To prevent or manage invasions of HABs into fish farms on an emergency basis, many methods have been proposed. Frequently over the past 30 years in coastal countries, treatments of clay and clay mixed with polyaluminum chloride (PAC) and chitosan have been tested for HAB-removal effectiveness in both the laboratory and the field. In Korea, yellow loess clay (hwangto) has been dispersed using electrolytic clay dispensers, both to decrease the amount of yellow loess clay's usage in containers and enhance HAB-removal efficiency. However, this emergency method has limitations, among which is the requirement for more effective controlling agents for field applications. Thus, in this paper, we review technologies for clay-based red tides prevention and control and their limitations, and, further, introduce next-generation algicidal technologies for the emergency protection of fish farms.