• Economic and Environmental Geology
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• v.19 no.spc
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• pp.73-94
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• 1986

In order to make preparation of the Metallogenic Map of Korea, the writer have to collect and review the data of general geology and ore deposits of Korea which have been published up to date. The geology of Korea has been briefly simplified and grouped into the 15 formations so as to provide the base geologic map for making the Metallogenic Map of Korea. Geologic provinces of south Korea are divided into four, that is, Gyeonggi·Ryeongnam province, Ogcheon geosynclinal province, Gyeongsang basin province and Tertiary province. In the view of tectonics and related granites, the major orogenies in south Korea are as follows; Ryeongnam orogeny, Taebaeg disturbance, post-Sangweon disturbance, post-Joseon disturbance, Bulgugsa disturbance and Yeonil disturbance. Metallogenic epochs might coincide with the period of syntectonic or subsequent igneous rock intrusions accompanied with the above listed orogenies and disturbances. Thus, metallogenic epochs that are certain in Korea so far are; Precambrian periods, Paleozoic periods, Jurassic to early Cretaceous periods, late Cretaceous to early Tertiary periods, Quaternary periods and age-unknown periods. The Metallogenic Map of Korea shows 444 ore deposits and/or mines by symbols on a background adopted from the existing geologic and tectonic map. The 444 metallic and non-metallic deposits are categorized by the commodities they contain, size, geologic environment, mineralized age and mineralogic nature.

• Journal of Ecology and Environment
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• v.31 no.3
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• pp.213-223
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• 2008

The increasing area of abandoned rice fields could provide new opportunities for wetland restoration in Asia. However, it is unknown how quickly or completely abandoned rice fields will recover from agricultural disturbances. We assessed water quality and plant community succession in abandoned rice fields with different hydrology in a mountain valley to understand the effects of hydrological regime on recovery. Water level, soil redox potential, water quality, plant composition, and primary production were measured. The sites, coded as D6, N13, and N16, had been recovering for 6, 13, and 16 years by 2006. N13 and N16 have been recovering naturally whereas D6 has been drained with a nearby dike and was tilled in 2001. The typical hydroperiods of D6, N13, and N16 were no surface water, permanently flooded, and seasonally flooded, respectively. The major change in vegetation structure of both D6 and N13 was the replacement of herbaceous species by woody species. Drawdown accelerated this change because Salix koreensis grew better in damp conditions than in flooded conditions. Phragmites japonica reduced plot-level plant species richness. The removal efficiency of $NH_4-N$, $NO_3-N$, and $PO_4-P$ from water varied seasonally, ranging between -78.8 to 44.3%, 0 to 97.5%, and -26.0 to 44.4%, respectively. In summary, abandoned rice fields quickly became suitable habitat for native wetland plant species and improved regional water quality. Variation among our sites indicates that it is likely possible to manage abandoned rice fields, mostly through controlling hydrology, to achieve site-specific restoration goals.

• Journal of Power Electronics
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• v.13 no.1
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• pp.139-160
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• 2013

In this paper, an intelligent robust control system (IRCS) for precision tracking control of permanent-magnet synchronous motor (PMSM) servo drives is proposed. The IRCS comprises a recurrent wavelet-based interval type-2 fuzzy-neural-network controller (RWIT2FNNC), an RWIT2FNN estimator (RWIT2FNNE) and a compensated controller. The RWIT2FNNC combines the merits of a self-constructing interval type-2 fuzzy logic system, a recurrent neural network and a wavelet neural network. Moreover, it performs the structure and parameter-learning concurrently. The RWIT2FNNC is used as the main tracking controller to mimic the ideal control law (ICL) while the RWIT2FNNE is developed to approximate an unknown dynamic function including the lumped parameter uncertainty. Furthermore, the compensated controller is designed to achieve $L_2$ tracking performance with a desired attenuation level and to deal with uncertainties including approximation errors, optimal parameter vectors and higher order terms in the Taylor series. Moreover, the adaptive learning algorithms for the compensated controller and the RWIT2FNNE are derived by using the Lyapunov stability theorem to train the parameters of the RWIT2FNNE online. A computer simulation and an experimental system are developed to validate the effectiveness of the proposed IRCS. All of the control algorithms are implemented on a TMS320C31 DSP-based control computer. The simulation and experimental results confirm that the IRCS grants robust performance and precise response regardless of load disturbances and PMSM parameters uncertainties.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.1020-1026
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• 2014

A problem of sliding mode control is chattering because of controle input signal included unknown disturbance and nonlinear input parameters. This paper presents a sliding mode controller design to inverted pendulum system. In this paper, a sliding mode control algorithm to reduce a chattering is proposed. The reduction of chattering is accomplished by smoothing function for nonlinear control input. In this method, the dynamic equations of the inverted pendulum is decoupled by considering nonlinear parameters and external disturbances. Therefore, this study is applied to obtain switching control inputs for sliding mode controller. The proposed technique is tested to the control of inverted pendulum through computer simulations. The result shown reduced chattering in control input.

• Journal of Ecology and Environment
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• v.46 no.2
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• pp.111-125
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• 2022

Background: Zanthoxylum armatum is one of the 30 prioritized medicinal plants for economic development of Nepal with a high trade value. Understanding the ecology of individual species is important for conservation and cultivation purposes. However, relation of ecological factors on the distribution and populations of Z. armatum in Nepal remain unknown. To address this knowledge gap, an attempt has been made to study the population structure, distribution, and regeneration potentiality of Z. armatum. Vegetation sampling was conducted at six different localities of Salyan district along the elevation range of 1,000 m to 2,000 m. Results: Altogether 50 plant species belonging to 44 genera under 34 families were found to be associated with Z. armatum. Significantly higher species richness was found at Rim (1,400-1,700 m) and Chhatreshwori (1,800-2,000 m) and lower at Kupinde (1,600-1,800 m). The highest population density of Z. armatum was at Kupinde (1,600-1,800 m) with a total of 1,100 individuals/ha. and the lowest at Chhatreshwori (1,800-2,000 m) with 740 individuals/ha. Based on the A/F value (Whitford index), it can be said that Z. armatum has random distribution in the study area. The plants were categorized into seedlings, saplings and adults based on plant height and the status of natural regeneration category determined. The regeneration potentiality of Z. armatum in the study area was fair with the average seedlings and saplings densities of 150 and 100 individuals/ha. Respectively. A Shannon-Weinner index mean value of 2.8 was obtained suggesting high species diversity in the study area. Conclusions: The natural distribution and regeneration of Z. armatum is being affected in the recent years due to anthropogenic disturbances. Increasing market demand and unsustainable harvesting procedures are posing serious threat to Z. armatum. Thus, effective conservation and management initiatives are most important for conserving the natural population of Z. armatum in the study area.

• Journal of the Korean Orthopaedic Association
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• v.54 no.4
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• pp.361-365
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• 2019

Spinal adhesive arachnoiditis is an inflammation and fibrosis of the subarachnoid space and pia mater caused by infection, trauma, spinal vascular anomalies, and iatrogenic (surgery and/or puncture). Adhesive arachnoiditis develops various symptoms and signs (gait disturbances, radiating pain, paralysis, and incontinence). On the other hand, adhesive arachnoiditis associated with cauda equina syndrome has not been reported in Korea until now. The authors experienced cauda equina syndrome caused by adhesive arachnoiditis of the lumbar spine with satisfactory results following decompression. We report this case with a review of the relevant literature.