• Korean Journal of Medicinal Crop Science
• /
• v.2 no.2
• /
• pp.154-161
• /
• 1994

This experiment was carried out to establish micropropagation system in Fritillaria thunbergii Miq. Through the culture of bulblet scales, stems, node-buds and shoot tips with special reference to the effect of physiological age of explant and plant growth regulators on bulblet formation. Number of formed bulblets was significantly increased in node-bud or stem tissue compared to scals segments and on the medium supplemented with kinetin than BA containing medium. Optimum levels of kinetin for bulblet formation from node-bud taken from above 3 cm shoot length and stem segments excised from below 3 cm shoot length were 5.0 mg /L and $1.0{\sim}3.0\;mg$ /L kinetin, respectively. Interesting phenomenon was observed, the direct formation of bulblets from the axilliary bud of cultured explants. Bulblet forming capacity in stem tissue was depended on stem age, young stem had high regeneration ability compared to old stem taken from above 10 cm shoot length. 1.0 mg /L kinetin was optimum concentration for the formation of bulblets from old stem segments. Stem tissue taken from underground growing plant was promoted coampare to shoot tips or bulb scale segments. Optimum concentration of sucrose was $5{\sim}7%$. Summariged above results revealed that effective explant for micropropagation was stem and /or node-bud tissue excised from less than 3 cm plant height compared to those of bulb scale segments which showed high contamination after culture. Maximum multiplication rate of young stem and /or node-bud segment was about 20 times. Kinetin requirement for stimulation of bulblet formation from cultured explant depended on source of explants but favorable levels of kinetin for organogenesis ranged from 1.0 mg /L to 5.0 mg /L.

• Korean Journal of Plant Resources
• /
• v.32 no.3
• /
• pp.237-243
• /
• 2019

Soybean is the one of recalcitrant legume species for shoot induction. Shoot regeneration via direct organogenesis was investigated in five soybean cultivars, 'Dawon', 'Pungsan', 'Daewon', 'Taekwang' and 'Chongdoo 1' by using cotyledonary node explants. Out of 5 soybean cultivars, an efficient shoot regeneration condition was developed in the two soybean cultivars, 'Dawon' and 'Pungsan'. When various kinds of plant growth regulators with different concentration were estimated, the optimum medium condition for shoot induction in both soybean cultivars was MS + B5 vitamin supplemented with BA at concentration 2 mg/L. In addition, shoot formation efficiency was increased with 97.09% and 93.88% by the pretreatment of BA onto the explants before in vitro culture in both cultivars. Shoot induction in 'Dawon' cultivar was originated from epidermal tissue and sub-epidermal layers when histological changes were investigated under shoot regeneration after culturing cotyledonary node segments on shoot induction medium for 0 to 21 days. Especially, cell dedifferentiation was observed from parenchyma cells to meristematic cell in 3-day cultured segments.

• Journal of Plant Biotechnology
• /
• v.8 no.1
• /
• pp.37-41
• /
• 2006

In vitro mass multiplication of Vanilla planifolia was investigated using node as explant. Multiple shoots were developed in MS medium supplemented with $2.0mgl^{-1}$ 6-benzylaminopurine and $1.0mgl^{-1}$ $\alpha$-naphthalene acetic acid. Multiple shoots were maintained for 6-T weeks with regular subculturing at the end of $3^{rd}$ week onto fresh medium. The maximum number of shoots at the rate of 12.8 per node segment was achieved over a period of four weeks. The elongated shoots were separated from the shoot clusters and were transferred onto half strength MS medium supplemented with indole-3-acetic acid ($1.0mgl^{-1}$) over a period of 28 days for induction of roots. The development of roots was observed on $7^{th}$ day of incubation. The in vitro raised plantlets were transferred to poly-cups, covered with polyethylene sheets and maintained under shade net for 25 days for hardening. Finally these plants were transferred to field and recorded that 85 % of tissue cultured plants were survived. From the present study, a simple and efficient micropropagation protocol was developed for Vanilla planifolia using single node segments as explants.

• Journal of Digital Convergence
• /
• v.17 no.9
• /
• pp.153-161
• /
• 2019

Discrimination of media object segments in wireless home proxies has a significant impact on caching delay, and caching delay degrades the performance of the proxy. In this paper, we propose a Single Fetching Smart Caching (SFSC) strategy and a Multi-Fetching Smart Caching (MFSC) strategy to improve the proxy performance of the home network and improve the caching performance for media object segments. The SFSC strategy is a technique that performs caching by sequential fetching of object segments requested by the home node one at a time, which guarantees a faster cache hit rate, and the MFSC strategy is a technique that caches the media object segments by blocking object segments requested by the home node one at a time, which improves the throughput of cache. Simulation results show that the cache hit rate and the caching delay are more efficient than the MFSC technique, and the throughput of the object segment is more efficient than that of the SFSC technique.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.4
• /
• pp.618-636
• /
• 1997

DQDB(Distributed Queue Dual Bus) protocol, the IEEE 802.6 standard protocol for metropolitan area networks, does not fully take advantage of the capabilities of dual bus architecture. Although fairness in bandwidth distribution among nodes is improved when using so called the bandwidth balancing mechanism, the protocol requires a considerable amount of time to adjust to changes in the network load. Additionally, the bandwidth balancing mechanism leaves a portion of the available bandwidth unused. In a high-speed backbone network, each node may act as a bridge/ router which connects several LANs as well as hosts. However, Because the existence of high speed LANs becomes commonplace, the congestionmay occur on a node because of the limitation on access rate to the backbone network and on available buffer spaces. to release the congestion, it is desirable to install some congestion control algorithm in the node. In this paper, we propose an efficient congestion control mechanism and fair and waster-free MAC protocol for dual bus network. In this protocol, all the buffers in the network can be shared in such a way that the transmission rate of each node can be set proportional to its load. In other words, a heavily loaded node obtains a larger bandwidth to send the sements so tht the congestion can be avoided while the uncongested nodes slow down their transmission rate and store the incoming segments into thier buffers. this implies that the buffers on the network can be shared dynamically. Simulation results show that the proposed probotol significantly reduces the segment queueing delay of a heavily loaded node and segment loss rate when compared with original DQDB. And it enables an attractive high throughput in the backbone network. Because in the proposed protocol, each node does not send a requet by the segment but send a request one time in the meaning of having segments, the frequency of sending requests is very low in the proposed protocol. so the proposed protocol signigificantly reduces the segment queuing dely. and In the proposed protocol, each node uses bandwidth in proportion to its load. so In case of limitation of available buffer spaces, the proposed protocol reduces segment loss rate of a heavily loaded node. Bandwidth balancing DQDB requires the wastage of bandwidth to be fair bandwidth allocation. But the proposed DQDB MAC protocol enables fair bandwidth without wasting bandwidth by using bandwidth one after another among active nodes.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.12B
• /
• pp.1435-1443
• /
• 2009

In this paper, an energy harvesting sensor network system is modeled and simulated by using the DEVS (Discrete Event System Specification) formalism. The system is composed of a sink (master) node, which is battery or mains powered, and a set of sensor (slave) nodes, each of which harvests ambient energy and converts it into electrical energy. For simulation, (i) the behavior of energy harvesting and storing circuits of the slave node is partitioned into a set of piecewise continuous segments and then each segment is represented as a discrete state; (ii) the interaction among the master node and components of the slave node is investigated preciously; and (iii) the investigated result is modeled and simulated by using the DEVS formalism.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2019.10a
• /
• pp.16-16
• /
• 2019

The Cassava (Manihot esculenta Crantz) is a perennial woody shrub cultivated mainly in the tropics for its starchy tuberous roots. It belongs to the family Euphorbiaceae which also includes rubber (Hevea brasiliensis) and castor bean (Ricinus communis). Among tropical crops, rice, sugarcane, maize and cassava are the most important sources of calories for human consumption. Problems in the propagation of cassava are virus diseases and low rates of seed germination. Thus, a study was undertaken to develop an efficient in vitro mass propagation protocol of Manihot esculenta Crantz. Young and actively growing stem segments were excised from adult plants of cassava. Samples were cut into a 3~4 cm nodal segments with single node after sterilization, and cultivated in the different medium supplemented with various plant growth regulators for 4 weeks. For shoot multiplication, single-node stem segments, approximately 1 cm in length, were taken from in vitro derived shoots and subcultured. After 4~6 weeks, the shoot generation rate was 55.6%, the shoot number and its length were 1.0/explant and 2.3 cm in the most favorable medium composition. Our experiments confirmed that in vitro growth and multiplication of plantlets could depend on its reaction to the different medium composition, and this micropropagation techniques could be a useful system for healthy and vigorous plant production.

• Journal of Korea Water Resources Association
• /
• v.55 no.spc1
• /
• pp.1187-1195
• /
• 2022

To run the algorithm for identifying the segments of a pipe network, the relative positional relation between nodes, pipes, and valves should be prepared as input information of a segment search algorithm. In order to more accurately identify the segments of real pipe network, pipe network GIS/CAD database that contains all isolation valves is more suitable than modeled pipe network information used for a hydraulic analysis program. In this study, we developed an algorithm that can establish the relative positional relations among node-pipe-valve suitable for pipe network segment search algorithms using GIS/CAD data of a real water supply network, and developed a MATLAB program that can implement it. The effectiveness of the developed MATLAB program was confirmed by applying it to a portion of a real municipal pipe network.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1999.03b
• /
• pp.22-25
• /
• 1999

A dynamic explicit finite element code for simulating sheet forming processes has been developed The code utilises the discrete Kirchhoff shell element and contact force is treated by a conventional penalty method. In order to reduce the computational cost a new and robust contact searching algorithm has been developed and implemented into the code. in the method a hierarchical structure of tool segments called a tree structure is built for each tool at the initial stage of the analysis Tree is built in a way to divide a trunk to 8 sub-trunk 2 in each direction until the lowest level of the tree(leaf) contains exactly one segment of the tool. In order to have a well-balanced tree each box on each sub level contains one eighth of the segments. Then at each time step contact line from a node comes out of the surface of the tool. Simulation of various sheet forming processes were performed to verify the validity of the developed code with main focus on he usefulness of the developed contact searching algorithm.

• Electronics and Telecommunications Trends
• /
• v.38 no.2
• /
• pp.36-45
• /
• 2023

Segment routing (SR) is a source-based routing architecture in which a node steers packets adhering to service and topological requirements. Using programmable segments, SR enables end-to-end service connectivity to satisfy the network constraints of various services. SR can be implemented with both MPLS and IPv6 dataplanes. This survey presents the overview of SR for IPv6 dataplane (SRv6), network programming technologies based on SRv6, and the SR deployment status.