• Journal of Institute of Control, Robotics and Systems
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• v.19 no.4
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• pp.349-356
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• 2013

This paper presents formation control based on potential functions for unicycle robots. The unicycle robots move to formation position which is made from a reference point and neighboring robots. In the framework, a local minimum case occurred by combination of potential repulsed from neighboring robots and potential attracted from a formation line is presented, in which the robot escapes from a local minimum using a virtual escape point after recognizing trapped situation. As well, in the paper, potential functions are designed to keep the same distance between neighboring robots on a formation line, i.e. the relative distance between neighboring robots on a formation line is controlled by a potential function parameter. The simulation results show that the proposed approach can effectively construct straight line, V, and polygon formation for multiple robots.

• Journal of Environmental Science International
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• v.21 no.8
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• pp.1015-1021
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• 2012

Formation of disinfection by-products (DBPs) including trihalomethans (THMs), haloacetic acid (HAAs), haloacetonitriles (HANs) and others from chlorination of algogenic organic matter (AOM) of Microcystis sp., a blue-green algae. AOM of Microcystis sp. exhibited a high potential for DBPs formation. HAAs formation potential was higher than THMs and HANs formation potential. The percentages of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) formation potential were 43.4% and 51.4% in the total HAAs formation potential. In the case of HANs formation potential, percentage of dichloroacetonitrile (DCAN) formation potential was 97.7%. Other DBPs were aldehydes and nitriles such as acetaldehyde, methylene chloride, isobutyronitrile, cyclobutanecarbonitrile, pentanenitrile, benzaldehyde, propanal, 2-methyl, benzyl chloride, (2-chloroethyl)-benzene, benzyl nitrile, 2-probenenitrile and hexanal.

• International Journal of Aeronautical and Space Sciences
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• v.6 no.2
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• pp.56-63
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• 2005

Some methods have been presented to avoid collisions among satellites for satellite formation flying mission. The potential function method based on Lyapunov's theory is known as a powerful tool for collision avoidance in the robotic system because of its robustness and flexibility. During the last decade, a potential function has also been applied to UAV's and spacecraft operations, which consists of repulsive and attractive potential. In this study, the controller is designed using a potential function via sliding mode technique for the configuration of satellite formation flying. The strategy is based on enforcing the satellite to move along the gradient of a given potential function. The new scalar velocity function is introduced such that all satellites reach the goal points simultaneously. Simulation results show that the controller drives the satellite toward the desired point along the gradient of the potential function and is robust against external disturbances.

• Journal of the Korean Ceramic Society
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• v.47 no.1
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• pp.8-18
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• 2010

When metal oxides are exposed to chemical potential gradients, ions are driven to diffusive mass transport. During this transport process, the divergence of ionic fluxes offers the formation/annihilation of oxides. Therefore, the divergence of ionic flux may play an important role in the void formation in oxides. Kinetic equations were derived for describing chemical potential distribution, ionic fluxes and their divergence in oxides. The divergence was found to be the measure of void formation. Defect chemistry in scales is directly related to the sign of divergence and gives an indication of the void formation behavior. The quantitative estimation on the void formation was successfully applied to a growing magnetite scale in high temperature oxidation of iron at 823 K.

• Journal of the Society of Naval Architects of Korea
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• v.61 no.3
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• pp.170-184
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• 2024

With the advancement of autonomous navigation technology in maritime domain, there is an active research on swarming Unmanned Surface Vehicles (USVs) that can fulfill missions with low cost and high efficiency. In this study, we propose a formation control algorithm that maintains a certain shape when multiple unmanned surface vehicles operate in a swarm. In the case of swarming, individual USVs need to be able to accurately follow the target state and avoid collisions with obstacles or other vessels in the swarm. In order to generate guidance commands for swarm formation control, the potential field method has been a major focus of swarm control research, but the method using the potential field only uses the position information of obstacles or other ships, so it cannot effectively respond to moving targets and obstacles. In situations such as the formation change of a swarm of ships, the formation control is performed in a dense environment, so the position and velocity information of the target and nearby obstacles must be considered to effectively change the formation. In order to overcome these limitations, this paper applies a method that considers relative velocity to the potential field-based guidance law to improve target following and collision avoidance performance. Considering the relative velocity of the moving target, the potential field for nearby obstacles is newly defined by utilizing the concept of Velocity Obstacle (VO), and the effectiveness and efficiency of the proposed method is verified through swarm control simulation, and swarm control experiments using a small scaled unmanned surface vehicle platform.

• The Korean Journal of Mycology
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• v.11 no.3
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• pp.105-108
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• 1983

The mycelial growth of Pythium graminicola, P. ultimum, P. rostratum was best at -3 osmotic potential. P. monospermum was best grown at -8 bars osmotic potential. Mycelial growth by Pythium spp. was prevented at -42 bars for P. graminicola, P. ultimum and P. monospermum. Sporangial formation by P. graminicola and P. ultimum was influenced by water potential in much the same way as mycelial growth: -3 bars was maximum and -42 bars or below was minimal. Pythium spp. tested was grown faster on PDA than other media including oat meal agar. P. ultimum was best grown on any media among Pythium spp. tested.

• International Journal of Computer Science & Network Security
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• v.22 no.2
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• pp.348-356
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• 2022

The article is devoted to substantiation of theoretical and methodical bases of formation of the organizational-economic mechanism of maintenance of stability of development of region on the bases of influence of potential-forming space in the conditions of formation of creative economy. It was found that the organizational-economic mechanism due to its multifaceted nature does not have a single generally accepted definition, and its acceptable scale and complexity is reflected in the structure, which is very dependent on the scope and conditions of its application, can be very different and contain different elements. In view of this, in order to highlight the characteristics that are inherent in the organizational-economic mechanism of sustainable development of the region on the basis of potential-forming space in the formation of creative economy, the article examines the properties and characteristics of direct organizational and economic mechanism. The necessity of basing the process of formation of any organizational-economic mechanism, including the organizational-economic mechanism of ensuring the sustainability of the region on the basis of the potential-forming space in the conditions of creative economy on the system of principles. In this context, the author's vision is proposed and a set of principles for the formation of organizational-economic mechanism for sustainable development of the region on the basis of the potential of the potential-forming space in the creative economy, as well as revealed the essence of each. According to the structural aspect, the organizational-economic mechanism of ensuring the sustainability of the region's development on the basis of the potential-forming space is proposed to be presented as a set of seven stages, which are implemented in a certain sequence. Within the limits of this research the sequence of realization of the stages making process of formation of the organizational-economic mechanism of maintenance of stability of development of region on the basis of influence of potential-forming space in the conditions of formation of creative economy is defined and their maintenance and essence is presented.

• Proceedings of the Korean Society for Language and Information Conference
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• 2007.11a
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• pp.340-348
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• 2007

This paper deals with the complex verb formation of passive and potential predicates and syntactic structures projected by these verbs. Though both predicates are formed with the suffix -rare which has been assumed to originate from the same stem, they show significantly different syntactic behaviors. We propose two kinds of concatenation of base verbs and auxiliaries; passive verbs are lexically formed with the most restrictive mode of combination, while potential verbs are formed syntactically via more flexible combinatory operations of function composition. The difference in the mode of complex verb formation has significant consequences for their syntactic structures and semantic interpretations, including different combination with the honorific morphemes and subjectivization of arguments/adjuncts of base verbs. We also consider the case alternation phenomena and their implications for scope construals found in potential sentences, which can be accounted for in a unified manner in terms of the optional application of function composition.

• Korean Chemical Engineering Research
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• v.59 no.2
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• pp.247-253
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• 2021

Electrocoalescence is an active technique in petroleum industry, formation of raindrop in cloud, and digital microfluidics. In the present work, electrocoalescence of two droplets under the constant electric potential in air was studied. Through this experiment, we found that the electrocoalescence process could be divided three phases; deformation, formation of liquid bridge, and merging. And the condition for formation of liquid bridge between two droplets was obtained. For the connection of experimental result in constant potential condition with general case in constant charge condition, relationship of charge and potential difference was deduced by numerical computation. In high electric potential case, flat interfaces after recoiling were observed. It was interpreted through a numerical simulation of electric field.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.4
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• pp.220-228
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• 2017

Since the fine particulate matters occurred from mainly combustion in industry and road transport effect to human respiratory health, the interest and importance are getting increased. In 2013, the World Health Organization (WHO) concluded that outdoor air pollution is carcinogenic to humans, with the particulate matter component ($PM_{10}$ and $PM_{2.5}$) of air pollution most closely associated with increased cancer incidence, especially cancer of the lung. Therefore, many researches have been studied in the quantification and data development of fine particulate matters. Currently, the Ministry of Environment and cities/regions are developing the fine particulate matter data and air emission information. Particularly just $PM_{10}$ and $PM_{2.5}$ data is used in the fine particulate matters warning and alert. The data of NOx, SOx, $NH_3$, which have the particulate matter formation potential are not well considered. Also, the researches related with particulate matter formation potential and respiratory effects by industrial sectors and cities/regions are not conducted well. Therefore, the purpose of this study is to evaluate and calculate particulate matter formation potential and respiratory effects in 11 industrial sectors and cities using NOx, SOx, $PM_{10}$, $NH_3$ data (developed by Ministry of Environment and National Institute of Environmental Research) in 2001 and 2013. The results of this study will be provided the particulate matter formation potential and respiratory effects and will be used for future the fine particulate matter researches.