• Journal of Ocean Engineering and Technology
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• v.23 no.6
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• pp.146-155
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• 2009

This paper considers the path tracking problem in a horizontal plane for underactuated (or non-holonomic) autonomous underwater vehicles (AUVs). Underwater mapping has been an important mission for AUVs. Recently, underwater docking has also become a main research field of AUVs. These kinds of missions basically require accurate attitude and trajectory control performance. However, the non-holonomic problem should be solved to achieve accurate path tracking for the torpedo-type of AUVs. In this paper, resolved motion and acceleration control (RMAC) is considered as a path tracking controller for an underactuated torpedo-shaped AUV, ISiMi. A set of numerical simulations is carried out to illustrate the effectiveness of the proposed RMAC scheme, and experimental data with ISiMi100 and discussions are presented.

• International Journal of Ocean System Engineering
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• v.3 no.1
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• pp.16-21
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• 2013

This paper presents a design of fuzzy PD depth controller for the autonomous underwater vehicle entitled KAUV-1. The vehicle is shaped like a torpedo with light weight and small size and used for marine exploration and monitoring. The KAUV-1 has a unique ducted propeller located at aft end with yawing actuation acting as a rudder. For depth control, the KAUV-1 uses a mass shifter mechanism to change its center of gravity, consequently, can control pitch angle and depth of the vehicle. A design of classical PD depth controller for the KAUV-1 was presented and analyzed. However, it has inherent drawback of gains, which is their values are fixed. Meanwhile, in different operation modes, vehicle dynamics might have different effects on the behavior of the vehicle. In this reason, control gains need to be appropriately changed according to vehicle operating states for better performance. This paper presents a self-tuning gain for depth controller using the fuzzy logic method which is based on the classical PD controller. The self-tuning gains are outputs of fuzzy logic blocks. The performance of the self-tuning gain controller is simulated using Matlab/Simulink and is compared with that of the classical PD controller.

• Journal of Crop Science and Biotechnology
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• v.11 no.2
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• pp.107-110
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• 2008

A high-efficiency, reproducible somatic embryogenesis system for strawberry cultivar Chandler was developed. Thirty-one somatic embryos per explant(max no.) were recorded in leaf discs which were cultured on medium containing MS salts+$B_5$ vitamins+2% glucose+4.0 mg $1^{-1}$TDZ(Thidiazuron) and incubated at $10{\pm}1^{\circ}C$ under darkness for one week followed by three weeks under 16-h photoperiod. The scanning electron microscopic(SEM) ontogeny revealed the normal development of somatic embryos from globular to heart-shaped and dissection microscopy from torpedo-shaped to cotyledonary-stage embryos. The maximum germination percentage of 48% could be obtained on MS medium containing kinetin(1.0 mg $1^{-1}$) and the maximum survival percentage(79%) of plantlets after four weeks was found to be in the mixture of vermiculite, peatmoss, and soilrite(1:1:1).

• Plant Biotechnology Reports
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• v.3 no.3
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• pp.205-211
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• 2009

An efficient in vitro regeneration protocol for moth bean [Vigna aconitifolia (Jacq.) Marechal] via somatic embryogenesis has been developed. Embryogenic callus cultures were established from the cotyledonary node as explant on semi-solid Murashige and Skoog (MS) medium supplemented with $0.75mg\;1^{-1}$ 2,4-dichlorophenoxyacetic acid (2,4-D) and $1.5mg\;1^{-1}$ 6-benzylaminopurine (BA) and with various additives ($50mg\;1^{-1}$ ascorbic acid and $25mg\;1^{-1}$ each of adenine sulphate, citric acid and $_L-arginine$). Numerous somatic embryos differentiated on MS basal nutrient medium supplemented with $0.25mg\;1^{-1}$ 2,4-D and $0.5mg\;1^{-1}$ of kinetin (Kin). Sustained cell division resulted in the formation of cell aggregates, which progressed to the globular- and heart-shaped somatic embryos and then, if they differentiated properly, to the torpedo shape and cotyledonary stages. The transfer of embryos onto fresh MS basal medium containing $0.2mg\;1^{-1}$ BA and $2.0mg\;1^{-1}$ gibberellic acid enabled the embryos to achieve complete maturation and germination. More than 80% of somatic embryos were converted into true-to-type fertile plants. In vitro-regenerated plantlets with well-developed roots were successfully hardened in a greenhouse and established in soil.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.2
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• pp.865-874
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• 2019

A controller for an underwater glider is presented. Considered underwater glider is a torpedo-shaped autonomous underwater vehicle installing adjustable buoyancy bag and movable battery in it. The controller is composed of an LQR controller to maintain zigzag vertical movement for gliding and two PD controllers to control elevator/rudder angles. The LQR controller controls the pumping speed into the buoyancy bag and the moving speed to locate the battery. One of the PD controller controls the elevator angle to assist the LQR controller, and the other controls the rudder angle to adjust the direction of the underwater glider. A reduced order Luenberger observer is adopted to estimates the center of gravity of the glider and the buoyancy mass that are essential but cannot be measured. Mathematical simulation using Matlab proved the validity of the proposed controller to obtain better performance than conventional LQR only controller under the influence of sea current.

• Journal of Plant Biotechnology
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• v.31 no.3
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• pp.219-223
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• 2004

Embryogenic calli were induced from petioles of Aralia elata on MS solid medium supplemented with 1.0 mg/L 2,4-D. When embryogenic calli were transferred to MS liquid medium supplemented with 1.0 mg/L 2,4-D, embryogenic cells and embryogenic cell clusters were developed after 2 weeks of culture. Embryogenic cells were filtered through a 250 ${\mu}{\textrm}{m}$ sieve and the passed cells were proliferated and maintained in MS liquid medium supplemented with 1.0 mg/L 2,4-D. Embryogenic cell clusters entrapped on the sieve were transferred to 1/2 MS liquid medium without plant growth regulators, globular-shaped embryos were developed from embryogenic cell clusters after 2 weeks of culture. Numerous early stage somatic embryos could be developed to heart-shaped, torpedo-shaped, cotyledonary embryos and plantlets in 5 L bioreactor. Above results suggest that effective somatic embryo proliferation can be achieved via bioreactor culture systems in Aralia elata.

• Korean Journal of Plant Tissue Culture
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• v.28 no.1
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• pp.21-24
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• 2001

Peucedanum japonicum $T_{HUNB}$ used as a edible and medicinal plants was investigated for in uitro regeneration. Callus formation occurred on leaf and stem explant cultures and showed spontaneous embryogenic and organogenic capability on MS basal medium supplemented with 0.1~5 mg/L NAA and 0~10 mg/L BA in dark. The regeneration was highest on the condition supplemented with 2.5 mg/L NAA and 10 mg/L BA. Development of the somatic embryo progressed through the globular, heart-shaped, torpedo-shaped and cotyledonary stage, typical of zygotic embryos. When the first somatic embryos was cultured on the medium supplemented with 0.2 mg/L NAA, secondary somatic embryo were induced with higher frequency on the hypocotyl then on the cotyledon and root.t.

• Journal of Korean Society of Forest Science
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• v.98 no.6
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• pp.719-725
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• 2009

This study was conducted to establish the optimal condition for acclimatization from somatic embryos of Eleutherococcus seoulensis. Torpedo-shaped embryos of Eleutherococcus seoulensis were cultured on 1/3 MS and WPM media supplemented with $GA_3$ (3.0, 5.0 mg/L) for 4 weeks. Plentlets were transferred to 1/2 SH solid medium with 1.0 mg/L $GA_3$ and 0.2% activated charcoal for shoot and root elongation and them elongated plantlets further developed on 1/2 SH medium for 4 weeks. Developed plantlets further elongated into well-shaped leaf and root system on 1/3 SH medium under ventilation condition for 4 weeks. Plantlets grew normally on 1/3 SH basal medium, were acclimated on various soil. Survival frequency of plantlets was influenced by soil type(peatmoss+perlite, perlite, soil on Nam mountain). The highest survival rate to soil was more than 70% when plantlets were 1/3 SH medium under ventilation condition in Nam mountain soil. These results indicate that the systematic procedure of plant production in Eleutherococcus seoulensis could be practically applicable for mass propagation.

• Korean Journal of Plant Resources
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• v.28 no.3
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• pp.350-356
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• 2015

Abeliophyllum distichum is a monotypic taxon of Oleaceae and endemic to Korea. A comprehensive study on embryogeny and fruit and seed coat ontogeny in Abeliophyllum was carried out via microtome and light microscopy. The fertilization occurs during mid– to late April and embryo matures by early July. The embryo development follows the general fashion from globular embryo – transition embryo – heart shaped embryo – torpedo embryo – walking-stick embryo to mature embryo. The pericarp clearly differentiates into three histological zones: exocarp, mesocarp, and endocarp. The young seed comprises 10-12 cells thick seed coat and the mature seed coat comprises an exotesta, 6-8 mesotesta and an endotesta. Any crystals, phenolic-like compounds, idioblasts, and the sclereids are not found in pericarp as well as seed coat. An overall development confirms Solanade type of embryogenesis in Abeliophyllum. The endocarp becomes more prominent in mature fruit and all the layers of endocarp are highly lignified. On the basis of mechanical layer the seed coat is of exotestal type.

• Journal of Plant Biology
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• v.39 no.2
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• pp.127-135
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• 1996

An efficient system of somatic embryogenesis was established for the red pepper plant (Capsicum annuum L. cv. Nokkwang) usign immature zygotic embryos. The size of the immature zygotic embryos and the concentrations of 2, 4-D and sucrose were found to be critical. Somatic embryos were induced via callus or directly from explants and regenerated into plantlets successfully. When zygotic embryos 1~2 mm long were cultured on the modified Murashige-Skoong (MS) medium supplemented with 2 mg/L 2, 4-D for 3 weeks in the dark, somatic embryos were induced directly from the apical region of zygotic embryos with the highest frequency being approximately 90%. To mature the somatic embryos, ABA and an ethylene inhibitor AgNO3 were used. The highest frequency of shoot regeneration (25% in each) resulted at 2$\mu$M ABA or 20$\mu$M AgNO3 treatment at rates 3.7 and 1.6 times control, respectively. Shoots developed mainly from the cotyledonary node on CoCl2-containing medium, and from the upper side of cotyledon on medium containing AgNO3 while the embryos on the control medium produced shoots from both the cotyledonary node and the upper region of cotyledons both at frequencies of 50%. Indirect somatic embryogenesis via callus was induced at an efficiency of approximately 10% with zygotic embryos 3~4 mm long cultured on MS medium containing 5~10 mg/L, 2, 4-D for 5~7 weeks under a continuous light condition. The plants regenerated from the somatic embryos were morphologically normal. Using scanning electron microscopy, the direct and indirect somatic embryogeneses were observed to follow the globular, heart and torpedo stages, similar to zygotic embryogenesis. Also, suspensors appeared in the early globular and ovoid-shaped late globular embryos during indirect somatic embryogenesis.