• Journal of Bio-Environment Control
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• v.11 no.4
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• pp.157-162
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• 2002

The efficient timer-controlled irrigation and the favorable fruiting position were investigated far highly quality melon fruits from Feb.18 to July Si 1999. The nutrient solution was supplied either at every hour from 6：00 to 18：00 (T-1) or at 6：00, 8：00, 10：00, 11：00, 12：00, 12：30, 13：00, 13：30, 14：00, 14：30, IS：00,16：00, and 17：00 (T-2). A fruit was set at the first node of the fruit bearing branch from the 10, 12, or 13th node of the main stem. Pot weight was maintained at almost n constant level, regardless of the daily integrated solar radiation in T-2. Soluble solids content (SSC) and fresh weight of fruit were not significantly different among the irrigation treatments at each harvesting time. At the first harvest, SSC and fresh weight of fruit were not significantly different between the fruiting positions within the irrigation treatment. At the second harvest, SSC was higher in T-2 than T-1. The SSC was low in the fruit of the loth node in T-1, while it was not significantly different between fruiting positions in T-2. Fruit fresh weight was the highest at the 12 and 13th nodes in T-1, and the 13th node in T-2. Fresh and dry weights of leaf except petiole, regardless of harvesting time, increased as the node position was higher, The higher the fruiting position was, the lower the leaf weight was. Therefore, it is recommended to irrigate more frequently during the mid-noon. Fruits can be harvested earlier at the lower nodes in the spring crop production.

• Current Research on Agriculture and Life Sciences
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• v.14
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• pp.61-65
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• 1996

This study was carried out to determine the effect of fruit-set position and number of fruit set per plant on yield and quality including netting in "Super VIP" melon cultivated in spring season. 1) In training system of one fruit per plant, index of netting was acceptable, regardless of the node position of fruit-set. The higher node order of fruit set was, the heavier, longer, bigger in diameter the fruit set was, and the thicker the flesh was. However, soluble suger content and storability was decreased with increased node order. 2) In training system of two fruit per plant, the higher the fruit-set position in node order was, the better the netting index, fruit quality including fruit weight, length, diameter, and thickness of flesh were, but there was no difference in storability. 3) Fruits produced by one-fruit-per-plant training were superior to those produced by two-fruit-per-plant training in maker quality including netting, sugar content, stcrability. The fruit set on 12th node in one-fruit-per-plant training were the best in market quality. 4) Yield was increased by two-fruit-per-plant training.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.2099-2106
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• 2006

In this paper, we addressed the node positioning method for minimizing the sensing energy consumption in wireless sensor networks with adjustable sensing ranges. It is necessary for minimizing the sensing energy consumption to minimize the overlapped sensing area by neighboring nodes. To find a optimal node position, we derived a optimal equations by using the overlapped areas, each node's radiuses and expended angles of opposite neighboring nodes. Based on it, we devised a new node positioning method, called as ASRC(Adjustable Sensing Ranges Control). Unlike existing condition based model, our proposed method was derived from mathematical formula, and we confirmed its validity of sensing energy consumption through simulations.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.8
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• pp.191-200
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• 2019

In an Ad-hoc network, a method of time synchronizing all the nodes in a network centering on one reference node can be used. A representative algorithm based on a reference node is Flooding Time Synchronization Protocol (FTSP). In the process of sending and receiving messages, predictable and unpredictable delays occur, which should be removed because it hinders accurate time synchronization. In multi-hop communications, hop delays occur when a packet traverses a number of hops. These hop delays significantly degrade the synchronization performance among nodes. Therefore, we need to find a method to reduce these hop delays and increase synchronization performance. In the FTSP scheme, hop delays can be greatly increased depending on the position of a reference node. In addition, in FTSP, a node with the smallest node ID is elected as a reference node, hence, the position of a reference node is actually arbitrarily determined. In this paper, we propose an optimal reference node election algorithm to reduce hop delays, and compare the performance of the proposed scheme with FTSP using the network simulator OPNET. In addition, we verify that the proposed scheme has an improved synchronization performance, which is robust to topology changes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.108-110
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• 2015

In this paper, we proposed the relay node selection scheme using property of node such as velocity, direction in Delay Tolerant Networks. the existing selection scheme is caused the problem increasing the transmission delay and packet loss, if select the relay node for different mobile with destination. To overcome this problem, we proposed the relay node selection scheme using the property of mobile node. the proposed scheme represents and shares the property of mobile node. The proposed algorithm assumed the sketchy position of node from mobile node delivering property of destination. In addition, the propose algorithm recognizes and analyzes the context of mobile node to provide the relay node transferring the data efficiently. The simulation result provides the better result in terms of transmission delay and packet delivery ratio by selecting transmission by relay node according property of node.

• Asian Journal of Turfgrass Science
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• v.11 no.2
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• pp.117-124
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• 1997

This study was carried out to investigate the growth and branching pattern of stolons at Korean lawn(Zoysia japonica Steud.) in the field condition. The results were summarized as follows ; 1.About 80% of observed lawns had one primary stolon. Among the lawns with several primary stolons, 30% of them had two primary stolons, 63% had three, and 7% had four. 2.The angles between the primary stolon and the shoot were increased from 0˚ to 52˚ according to the node order from the terminal shoot apex, and reached maximum angle at the 7th node. 3.The internode length was the longest in the middle position of stolon, and its growing rate which depends on months was increased from May to September. 4.The branching angles between primary and secondary stolon were from 44˚ to 53˚ in each node. The average left branching angle was about 48.20, right branching angle 47.8˚, and the total average branching angle was 48.00. 5.The rate of initial brabch was the highest at the 10th node in May, the 7th node in July and the 5th node in September. But, the initial branching rate at the 7th node in July was higher than any other that at the 10th node in May and the 5th node in September. 6.The distribution rate of secondary stolon in each node of primary stolon was the highest at the 7th node. 7.when the terminal shoot apex of primary stolon was damaged mechanically, the branching rate at the first node after the damaged region was highly increased to 62%. The results of this study may be suggested that the secondary stolon begins to branch with the angle of 480 from the 7th node of the normal primary stolon, and those may be used as a basic data for the branching simulation in lawn.

• KIISE Transactions on Computing Practices
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• v.24 no.1
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• pp.1-9
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• 2018

Low-power long-range networks (LoRa) has a comprehensive coverage of up to 30 km, so that long-range positioning is possible. However, the position error in the current LoRa environment is over 500 m. This makes it difficult to use practical location services in the LoRa environment. In this paper, we propose a method to improve the position accuracy by correcting an inaccurate visual error when sending a signal from a mobile node to a gateway through the reference node of each zone in the LoRa environment. Experiments were carried out using MATLAB, and a radio propagation algorithm, the Hata model, was used to cancel out the stationary noise and to evaluate the environmental noise. Experimental results showed that the error range decreased as the number of reference nodes increased and a mobile node approach the reference node.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.857-860
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• 2008

In this paper, we proposed cooperative based localization algorithm for wireless sensor networks, which can estimate to unknown node position using received signal strength table set. The unknown nodes are monitor to RSS from neighbor nodes and exclude existence possibility area of sensor node in sensor field. Finally, we can calculate the centroid position for each unknown node with cooperative localization algorithm. Furthermore, these processes are applied iteratively about all nodes which is recorded to RSS table and can estimate for unknown nodes.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.11
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• pp.1031-1040
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• 2014

In this paper, a new condition diagnosis algorithm for the lens injection molding process using various features extracted from cavity pressure, nozzle pressure and screw position signals is developed with the aid of probability neural network (PNN) method. A new feature extraction method is developed for identifying five (5), seven (7) and two (2) critical features from cavity pressure, nozzle pressure and screw position signals, respectively. The node energies extracted from cavity and nozzle pressure signals are also considered based on wavelet packet decomposition (WPD). The PNN method is introduced to build the condition diagnosis model by considering the extracted features and node energies. A series of the lens injection molding experiments are conducted to validate the model, and it is demonstrated that the proposed condition diagnosis model is useful with high diagnosis accuracy.

• Journal of Sensor Science and Technology
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• v.26 no.3
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• pp.199-203
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• 2017

In this paper, we developed an underwater localization system for underwater robot docking using the electromagnetic wave attenuation model. Electromagnetic waves are generally known to be impossible to use in water environment. However, according to the conclusions of the previous studies on the attenuation characteristics in underwater, the attenuation pattern is uniform and its model was accurately proposed and verified in 3-dimensional space via the omnidirectional antenna. In this paper, a docking structure and localization sensor system are developed for a widely used cone type docking mechanism. First, we fabricated electromagnetic wave range sensor transmit modules. And a mobile sensor node is equipped with unmanned underwater vehicle(UUV)s. The mobile node senses the four different signal strength (RSS: Received Signal Strength) from fixed nodes, and the obtained RSS data are transformed to each distance information using the 3-Dimensional EM wave attenuation model. Then, the relative localization between the docking area and underwater robot can be achieved according to optimization algorithm. Finally, experimental results show the feasibility of the proposed localization system for the docking induction by comparing the errors in the actual position of the mobile node and the theoretical position through the model.