• Korean Journal of Soil Science and Fertilizer
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• v.21 no.4
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• pp.434-442
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• 1988

This study has been made to investigate the influences of organic matter on the soil composition, nitrogen fixing organism, soil enzyme activity and nitrogen fixing activity in the paddy rice rhizosphere when rice and barley straw were applied. The results are summarized as follows: 1. The pH in the submerged soil was increased from ear formation stage to harvesting. 2. In the rhizosphere, $Fe^{{+}{+}}$ content was decreased according to the growing stage, while increased in the nonrhizosphere. 3. In the initial stage, rhizosphere was higher than nonrhizosphere but in the late stage nonrhizosphere was higher than rhizosphere on the $NH_4-N$ content. 4. In the submerged soil, rhizosphere was higher than nonrhizosphere, on the concentration of glucose and pentose. 5. Changes of the number of nitrogen fixing organism in whole soil was not high. 6. Generally, rhizosphere was higher than nonrhizosphere on the soil enzyme activity such as phosphatase, ${\beta}$-glucosidase, and protease. 7. Acetylene-reducing activity was the highest in the tillering stage, and rhizosphere, Samgang (high-yielding variety) were higher than nonrhizosphere. Dongjin (general variety) respectively. 8. In the submerged soil applied barley straw, acetylene-reducing activity was slightly higher than rice straw in the initial stage.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.5
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• pp.44-49
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• 2014

As expansion and contraction of bike disk brake are happened continuously by temperature at repeated urgent braking. In this study, 3 kinds of model are designed according to configurations of holes and thermal durabilities on bike disk brake are investigated by comparing 3 models through temperature and thermal analyses. Maximum thermal stress happened at the disk contacted with pad and the connection part fixing disk rotor. Instead of initial state, the temperature is uniformly distributed at transient state. As the area of hole at disk rotor face becomes wider, thermal stress becomes lower at the initial state. On the other hand, in case the number of holes increases, thermal stress becomes lower at the elapsed time of 100 seconds. The thermal durability of bike disk brake can be improved by applying this study result with configurations of holes.

• Journal of Microbiology and Biotechnology
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• v.16 no.11
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• pp.1661-1677
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• 2006

Rhizobium and related genera are soil bacteria with great metabolic plasticity. These microorganisms survive in many different environments and are capable of eliciting the formation of nitrogen-fixing nodules on legumes. The successful establishment of symbiosis is precisely regulated and requires a series of signal exchanges between the two partners. Quorum sensing (QS) is a prevalent form of population density-dependent gene regulation. Recently, increasing evidence indicates that rhizobial quorum sensing provides a pervasive regulatory network, which plays a more generalized role in the physiological activity of free-living rhizobia, as well as during symbiosis. Several rhizobia utilize multiple, overlapping quorum sensing systems to regulate diverse properties, including conjugal transfer and copy number control of plasmids, exopolysaccharide biosynthesis, rhizosphere-related functions, and cell growth. Genomic and proteomic analyses have begun to reveal the wide range of functions under quorum-sensing control.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.65-71
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• 2004

The Development of GPS practical using and systematic fixing for GPS Quality Control System on On-Line. Developed the program that can prove GPS quality about GPS permanent observation stations or user GPS data in server client system environment of Web-Based objectively Developed Save-module of graph display of analysis result data and reporter form. Developed the program for making an estimate of GPS satellite information in server client system environment of Web-Based. Designed that the Display can be possible and store estimate result can expresses the form such as Sky Plot, DOPs, Satellite Elevation, satellite number cf predict-time and then the result can be preserved for report form.

• Molecules and Cells
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• v.27 no.2
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• pp.129-134
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• 2009

Legume plants develop root nodules to recruit nitrogen-fixing bacteria called rhizobia. This symbiotic relationship allows the host plants to grow even under nitrogen limiting environment. Since nodule development is an energetically expensive process, the number of nodules should be tightly controlled by the host plants. For this purpose, legume plants utilize a long-distance signaling known as autoregulation of nodulation (AON). AON signaling in legumes has been extensively studied over decades but the underlying molecular mechanism had been largely unclear until recently. With the advent of the model legumes, L. japonicus and M. truncatula, we have been seeing a great progress including isolation of the AON-associated receptor kinase. Here, we summarize recent studies on AON and discuss an updated view of the long-distance control of nodulation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.2
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• pp.428-439
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• 2011

The main challenge in building efficient broadcast systems is to encrypt messages with short ciphertexts. In this paper, we present a new construction based on the identity. Our construction contains the desirable features, such as constant size ciphertexts and private keys, short public keys and not fixing the total number of possible users in the setup. In addition, the proposed scheme achieves the full security which is stronger than the selective-identity security. Furthermore we show that the proof of security does not rely on the random oracles. To the best our knowledge, it is the first efficient scheme that is full security and achieves constant size ciphertexts and private keys which solve the trade-off between the ciphertext size and the private key size.

• Coupled systems mechanics
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• v.10 no.2
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• pp.185-198
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• 2021

An analytical model is consider to scrutinize axisymmetric wave propagation in multiferroic hollow cylinder with rotating and initial stressed forces, where a piezomagnetic (PM) material layer is bonded to a piezoelectric (PE) cylinder together by Linear elastic materials with voids. Both distinct material combos are taken into account. Three displacement potential functions are introduced to uncouple the equations of motion, electric and magnetic induction. The numerical calculations are carried out for the non-dimensional frequency by fixing wave number and thickness. The arrived outputs are plotted as the dispersion curves for different layers. The results obtained in this paper can offer significance to the application of PE/PM composite hollow cylinder via LEMV and CFRP layers for the acoustic wave and microwave technologies.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.2
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• pp.50-58
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• 1998

Genetic Algorithm (GA) consists of selection, reproduction, crossover and mutation processes and many parameters including population size, generation number, the probability of crossover (Pc) and the probability of mutation (Pm). Determining values of the parameters is found critical in the whole optimization process and a sensitivity analysis with them seems mandatory. This paper tries to demonstrate such importance of sensitivity analysis of GA using an example water supply tunnel network of the New York City. For optimization of the network with GA, Pc and Pm vary from 0.5 to 0.9 by an increment of 0.1 and from 0.01 to 0.05 by an increment of 0.01, respectively, while fixing both the population size and the generation number to 100. This sensitivity analysis results in an optimum design of 22.3879 million dollars at the values of 0.8 and 0.01 for Pc and Pm, respectively. In addition, the probability of recombination (Pr) is introduced to check its applicability in the GA optimization of water distribution network. When Pr is 0.05 with the same values of Pc and Pm as above, the optimum design costs 20.9077 million dollars. This is lower than the cost of 22.3879 million dollars for the case of not using Pr by 6.6%. These results indicate that conducting a sensitivity analysis with parameter values and using Pr are useful in the optimization of WDN.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.8
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• pp.719-726
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• 2000

A real-time precise positioning is possible with GPS carrier phase measurements with efficient integer ambiguity resolution techniques. It is known that more reliable and fast integer ambiguity resolution is possi-ble as the number of measurements increases. Most precise positioning systems use dual frequency measurements and the wide-lnae technique to resolve integer ambiguity. The wide-lane technique magnifies the measurement noise while it reduces the number of candidates to be examined. In this paper a new integer ambiguity resolution method using dual frequency is proposed The proposed method utilizes the relationship between the wide-lane single frequency and the narrow-lane ambiguities to resolve narrow-lane integer ambiguity after fixing the wide-lane integer ambiguity. Experiments with real data show that the proposed method gives fast and reliable results.

• Journal of Positioning, Navigation, and Timing
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• v.9 no.3
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• pp.237-248
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• 2020

GNSS has been evolving dramatically in recent years. There are currently 6 GNSS (4 GNSS, AND 2 RNSS) constellations, which are GPS (USA), GLONASS (Russia), BeiDou (China), Galileo (EU), QZSS (Japan), and IRNSS (India). The Number of navigation satellites is expected to be over 150 by 2020. As the number of both constellations and satellites used for the improvement of positioning performance, high accuracy, and robustness of precise positioning is more promising. However, a large amount of the correction messages is required to support the augmentation system for the available satellites of all the constellations. Since bandwidth for the correction messages is generally limited, sending or scheduling the correction messages might be a critical issue in the near future. In this study, we analyze the relationship between the size of the bandwidth and Real-Time Kinematics (RTK) performance. Multiple Signal Messages (MSM), the only Radio Technical Commission for Maritimes (RTCM) message that supports multi-constellation GNSS, has been used for this assessment. Instead of the conventional method that broadcasts all the messages at the same time, we assign the MSM broadcasting interval for each constellation in 5 seconds. An open sky static and dynamic test for this study was conducted on the roof of Sejong University. Our results show that the RTK fixed position accuracy is not affected by the 5-second interval corrections, but the ambiguity fixing rate is degraded for poor DOP cases when RTK correction are transmitted intermittently.