• Journal of the Society of Naval Architects of Korea
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• v.56 no.6
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• pp.550-558
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• 2019

The roll motion of a general vessel, which is more influenced by resonance as compared to other motions, adversely affects the passenger and hull. Therefore, reducing the roll motion through an anti-rolling system is critical, and most ships use various devices such as anti-rolling tanks, bilge keels, and fin stabilizers to accomplish this. In this study, a simplified model is developed for the application of an anti-rolling device for unmanned semi-submersible vessels. The applied anti-rolling device is installed on the stern and stem of a ship using a pair of servo motors with added weight, and the motor is controlled through the Arduino. The moment of the motor is designed and implemented based on a mathematical model such that it is calculated through the restoring force according to the heel angle of the ship. The performance of the proposed system was verified by utilizing the roll damping coefficient calculated by the free-roll decay test and logarithmic decrement method and was validated by a towing tank test. The system is expected to be used for unmanned vessels to perform sustainable missions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.7
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• pp.572-580
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• 2013

IEEE 802.15.4e is a prospective standard for low latency control application in industries. This paper proposes a framework to evaluate the closed loop IEEE 802.15.4e based WNCS performance. The framework consists of two models: closed loop control system model and network model. The network model focuses on the PHY parameters of wireless link and takes the channel parameters into consideration. The PHY model combining with MAC model gives the control system model the probability of packet loss in a super-frame. In addition, redundancy mechanism is considered in IEEE 802.15.4e to reduce to data frame loss probability. The simulation is implemented in Matlab, PHY model takes the channel parameters from empirical results. Hence our evaluation gives insight into behavior of WNCS in different environments and it provides us a tool to design wireless network to achieve a good performance for control system.

• Journal of Biomedical Engineering Research
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• v.21 no.3 s.61
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• pp.303-309
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• 2000

An accurate quantitative biomechanical evaluation for the spasticity caused by the disorder of central nervous system was made in this study. A sudden leg dropper was designed to generate objective testing environment at every trial. 3-dimensional motion analysis system(Elite. B.T.S. Italy) was used to measure kinematic data which were angle. and angular velocity of a lower limb. A program was developed to analyze the kinematic data of lower limb motion. and dynamic EMG data at the same time. To evaluate spasticity quantitatively. total 26 parameters including 14 parameters newly driven were analyzed, and statistical analysis were made for bilateral correlations. Results showed possibility to make accurate quantitative and objective evaluation for spasticity with various new parameters using new devices and program.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.1
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• pp.35-51
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• 2012

The vascular plants in Bukhansan Dulegil, Jingwan-dong Wetland and Bukhan-dong Cheolgeoji were listed 432 taxa (8.9% of all 4,881 taxa of vascular plants); 95 families, 274 genera, 345 species, 2 subspecies, 69 varieties and 16 forms. Divided into woody plants were 145 taxa (33.6%) and herbaceous plants were 287 taxa (66.4%). The Bukhansan Dulegil were listed (Myeongsang-gil 159 taxa, Huingureum-gil 227 taxa, Wooyiryeong-gil 216 taxa, Banghakdong-gil 139 taxa, Boru-gil 199 taxa), Jingwan-dong Wetland were listed 147 taxa and Bukhan-dong Cheolgeoji were listed 129 taxa. Based on the list of rare plants by Korea Forest Service and Korea National Arboretum were Viola albida Palibin (Violaceae), Iris minutiaurea Makino (Iridaceae) and Korea National Arboretum were endemic plants, Philadelphus schrenkii Rupr. var. schrenkii (Saxifragaceae), Weigela subsessilis L.H. Bailey (Caprifoliaceae). Based on the list of floristic regional indicator plants by Korean Ministry of Environment were total 22 taxa; Wisteria floribunda DC. for. floribunda in class IV, 3 taxa (Betula davurica Pall., Mukdenia rossii Koidz., Glechoma grandis Kuprian., etc.) in class III, 5 taxa (Acer triflorum Kom., Viola orientalis W. Becker, Heloniopsis koreana Fuse & Al., etc.) in class II and 13 taxa (Camptosorus sibiricus Rupr., Clematis patens C. Morren & Decne., Cirsium pendulum Fisch. ex DC., etc.) in class I. Based on the list of naturalized plants, 16 families, 35 genera, 37 species, 3 varieties, 1 form, total 41 taxa (Rumex crispus L., Abutilon theophrasti Medicus, Panicum dichotomiflorum Michx. etc.), naturalization rate was 9.5% of all 432 taxa of vascular plants and urbanization index was 13.3% of all 309 taxa of naturalized plants. Ecosystem disturbing wild plants were 5 taxa; Rumex acetocella L., Ambrosia artemisiifolia L., Ambrosia trifida L. var. trifida, Eupatorium rugosum Houtt., Aster pilosus Willd.

• Applied Biological Chemistry
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• v.39 no.5
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• pp.409-413
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• 1996

To search for bioactive compounds from plant resources, 80% methanol extracts of 46 species of weeds were screened for their activities of antimicrobial, antioxidative, antiblebing, antitumor and herbicidal. Among extracts tested, some showed activities at the concentration of $50\;to\;100\;{\mu}g/ml$. Phryma leptostachya var. asiatica, Aster ageratoides, Centipeda minima, Cirsium pendulum, Lythrum anceps showed antibacterial activity. Penthorum chinense, Lindernia procumbens, Aster ageratoides, Dianthus superbus var. longicalycinus showed antiblebing activity. Phyma leptostachya var. asiatica, Juncus effusus var. decipiens, Lindernia procumbens, Aster ageratoides, Dianthus superbus var. longicalycinus, Viscum album var. coloratum showed antitumor activity. Juncus effusus var. decipiens, Hypericum ascyron, Juncus papillosus, Inula britannicar var. chinensis, Scirpus wichurae, Hypericum laxum showed antioxidant activity.

• Polymer(Korea)
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• v.28 no.3
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• pp.273-280
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• 2004

Acrylic resins (ethyl methacrylate-2-hydroxypropyl methacrylate-n-butyl acrylate-acrylic acid EHBCs) containing 80％ of solid were synthesized. Then, high-solid coatings (ethyl methacrylate-2-hydroxypropyl methacrylate-n-butyl acrylate-acrylic acid/hexamethylene diisocyanate-biuret : EHBCNs) were prepared by curing of the acrylic resin with curing agent hexamethylene diisocyanate-biuret at room temperature. The cure time of prepared coatings EHBCN-4 (EHBC-4 : $T_{g}$ = $0^{\circ}C$) and EHBCN-7 (EHBC-7 : $T_{g}$ = 3$0^{\circ}C$), measured by rigid-body pendulum method, was recorded 6.2 hours and 4.5 hours, respectively. Dynamic viscoelastic experiment revealed the glass transition temperature of EHBCN-4 and EHBCN-7 to be $14^{\circ}C$ and $39^{\circ}C$, respectively. It was found that the adhesion and flexural properties among various properties of coatings were enhanced by the incorporation of caprolactone acrylate monomer into the acrylic resins.

• The Journal of Korean Obstetrics and Gynecology
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• v.18 no.1
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• pp.64-80
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• 2005

The pharmacological effects of medicinal remedies traditionally used in Asian countries for improving the blood circulation were examined on isolated rat thoracic aorta strips in organ baths. Each experimental medicine was consecutively extracted under reflux with water. Of 17 plants, Curcuma longa (CL) having the strongest acute relaxant activity in endothelium-intact arteries, Mucunae caulis (MC), Cirsium pendulum (CP), Rumex longiflius (RL), Paeonia suffruticosa (PS), Curcuma zedoaria (CZ), Scirpus maritimus (SM), Siphonostegia chinensis (SC), Leonurs sibiricus (LS) and Typha orientalis (TO) were showing dose-dependent relaxant activity. Long-term relaxant effects were showed in Curcuma aromatia (CA), MC, CP, RL, PS, Potulacae grandiflorae (PG), CZ, Panax notoginseng (PN), Achyranthes japonica (AJ), CL, SC, Lycoppus lucidus (LL) and Corydalis turtschaninovii (CT). In endothelium-injury test using carbachol, CL, SC, MC, RL and PS which are having the acute vasorelaxing activity and CA and CT which are not showing vasorelaxaing activity were damaged to endothelium. As a result of this study, the possibility that a part of medicinal remedy may contribute to the beneficial effects in blood circulation was proposed, but inter-individual variation has been observed. Also, further studies on the vasorelaxant effects of these remedies are still required.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.25-25
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• 2019

Chromosome numbers and karyotypes in flowering plants have been considered to be prominent features in taxonomic and evolutionary context. Despite the increasing numbers of cytological studies in Asteraceae, karyotype analysis of Cirsium Mill. and Carddus L. in Korean population have not been performed carefully. In this study, the chromosome numbers and karyotype analysis of all eight species of the genus Cirsium Mill. and one species of Carddus L. were analyzed. While the chromosome number in Carduus crispus L. was diploid (2n = 2x = 18 or 18+2Bs) with x = 9 as the base chromosome number, all seven species of Cirsium were diploid with x = 17 except for Cirsium lineare (Thunb.) Sch. Bip. (x = 14). The chromosome number in C. pendulum Fisch. ex DC. presented 2n = 2x = 34 from two populations and C. lineare exhibited 2n = 2x = 28 from one population. Aneuploidy was occasionally found in C. japonicum Fisch. ex DC. var. spinossinum Kitam. (2n = 2x = 34, 35, 36), C. rhinoceros (H. $L{\acute{e}}v.$ & Vaniot) Nakai (2n = 2x = 32, 34), C. setidens (Dunn) Nakai (2n = 2x = 30, 31, 32) and C. vlassovianum Fisch. ex DC. (2n = 2x = 31, 32). While Cirsium japonicum Fisch. ex DC. var. japonicum possessed several B-chromosomes (2n = 2x = 34, 35, 36), polyploidy was only encountered in Cirsium nipponicum (Maxim.) Makino. (2n = 4x = 68) from two populations in Ulleung Island. The present cytological data might be contributed to the taxonomic and evolutionary studies in the genus Cirsium.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.10
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• pp.705-711
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• 2019

Dynamic behaviors of the deployable composite reflector antenna are numerically and experimentally investigated. Equations of the motion are formalized using Kane's equation by considering multibody systems with two degrees of freedom such as folding and twisting angles. To interpret structural deformations of the reflector antenna, the composite reflector is modeled using a beam model with the FSDT(First-order Shear Deformation Theory). To determine design parameters such as a torsional spring stiffness and a damping coefficient depending on deployment duration, an inverted pendulum model is simply applied. Based on the determined parameters, dynamic characteristics of the deployable reflector are investigated. In addition, its results are verified and compared through deployment tests using a gravity compensation device.

• Structural Engineering and Mechanics
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• v.19 no.4
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• pp.381-399
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• 2005

Base isolation technologies have been proven to be very efficient in protecting structures from seismic hazards during experimental and theoretical studies. In recent years, there have been more and more engineering applications using base isolators to upgrade the seismic resistibility of structures. Optimum design of the base isolator can lessen the undesirable seismic hazard with the most efficiency. Hence, tracing the nonlinear behavior of the base isolator with good accuracy is important in the engineering profession. In order to predict the nonlinear behavior of base isolated structures precisely, hundreds even thousands of degrees-of-freedom and iterative algorithm are required for nonlinear time history analysis. In view of this, a simple and feasible exact formulation without any iteration has been proposed in this study to calculate the seismic responses of structures with base isolators. Comparison between the experimental results from shaking table tests conducted at National Center for Research on Earthquake Engineering in Taiwan and the analytical results show that the proposed method can accurately simulate the seismic behavior of base isolated structures with elastomeric bearings. Furthermore, it is also shown that the proposed method can predict the nonlinear behavior of the VCFPS isolated structure with accuracy as compared to that from the nonlinear finite element program. Therefore, the proposed concept can be used as a simple and practical tool for engineering professions for designing the elastomeric bearing as well as sliding bearing.