• Bulletin of the Korean Chemical Society
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• v.22 no.2
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• pp.210-212
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• 2001

The predissociating resonances are treated for the SH molecule by quantal method. The isolated resonances (N'=0, v' = 0-6) are predicted to be highly Lorentzian. The widths and positions of the isolated resonances are computed as functions of v'. The magnitudes and signs of the widths and the shifts as functions of v' are discussed in terms of the distance of the resonance from the crossing points between the bound state (A 2Σ+ ) and the repulsive states ( 4Σ- , 2Σ- and 4Π).

• Composites Research
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• v.18 no.4
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• pp.14-20
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• 2005

To determine the effect of chemical structure of aromatic amino curing agents on thermal and mechanical properties, standard epoxy resin DGEBF (diglycidylether of bisphenol F) was cured with diaminodiphenyl methane (DDM) and diaminodiphenyl sulphone (DDS) in a stoichiometrically equivalent ratio. From this work the effect of aromatic amino curing agents on the thermal and mechanical properties is significantly influenced by the chemical structure of curing agents. In contrast, the results show that the DGEBF/DDS system having the sulfone structure between the benzene rings had higher values in the thermal stability, density, shrinkage ($\%$), thermal expansion coefficient, tensile modulus and strength, flexural modulus and strength than the DGEBF/DDM system having methylene structure between the benzene rings, whereas the DGEBF/DDS system presented low values in maximum exothermic temperature, conversion of epoxide, and grass transition temperature. These results are caused by the relative effects of sulfone group having strong electronegativity and methylene group having (+) repulsive property. The result of fractography shows that the grain distribution of DGEBF/DDS system is more irregular than that of the DGEBF/DDM system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.7
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• pp.679-688
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• 2010

The major objective of the present study is to extend the applications of inverse analysis to more realistic engineering fields with a complex combustion process rather than the traditional simple heat-transfer problems. In order to do this, the unknown initial mass fractions of $CH_4/O_2$ are estimated from the temperature measurement data by inverse analysis in the practical diffusion-controlled turbulent combustion problem. In order to ensure efficient inverse analysis, the repulsive particle swarm optimization (RPSO) method, which belongs to the class of stochastic evolutionary global optimization methods, is implemented as an inverse solver. Based on this study, it is expected that useful information can be obtained when inverse analysis is used in the diagnosis, design, or optimization of real combustion systems involving unknown parameters.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.2
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• pp.159-164
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• 1996

Food intake of birds can be affected by particle size as well as diet composition, In order to investigate whether food intake of diets including excessive amount of phenyalanine(Phe) was influenced by diet types. a series of experiments were conducted in growing chicks and laying hens. Growing chicks significantly decreased food intake in a semipurified excessive Phe diet compared with a semipurified control diet, while laying hens fed a practical diet including excess Phe did not significantly reduce their food intake over a corn starch-substituted control diet. In an attempt to find out whether diet type affects food intake in layers, the semipurified type diet with excess Phe greatly reduced food ingestion, but the effect was delayed in the practical type diet. Moreover, under choice feeding regimes between the Phe and either starch, tyrosine(Tyr) or fiber diets in order to investigate whether the decreased food intake in the presence of an excess of dieary Phe in laying hens is involved in the palatability for the diet, there was no significant difference between Phe and starch diet while a preference for the Phe diet tended to be increased when birds were offered Tyr. Laying hens ingested significantly more the Phe diet than the fiber diet within 1 h after feeding. For supporting the idea that preference for the Phe diet may be affected by manipulating taste sense, an anaesthetic or saline was intramuscularly administered under the tongue just before a choice feeding. Preference for the Phe diet was not significantly different from that for the fiber reference diet within 1 h in the anaesthetized birds while the birds preferred the Phe diet in the saline treated group. It is suggested that because birds are able to select a diet, the decreased food intake induced by dietary excess Phe may be due to the repulsive effect of Phe after ingestion but not the taste of Phe.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.1
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• pp.45-52
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• 2016

One commercial package for magnetic analysis was used to apply repulsive forces of permanent magnetics to bicycle cushion system. Reliabilities of finite element analysis were acquired by comparing with those of experimental measurements. Equivalent spring stiffnesses corresponding to various sizes of magnetics were implemented into the bicycle dynamic model with three degree of freedom. Input force caused at front and rear wheels due to road unevenness was considered in the dynamic model. Dynamic behaviors were observed in terms of vertical displacements of the rider and the front reach as well as pitching displacement of the mass center when the bicycle ran over half-triangular bump. The methodology suggested in this paper by the finite element analysis and numerical model will be an useful tool for more accurate prediction of cushion design for any vehicle system if magnetic forces are utilized.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.1
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• pp.19-24
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• 2011

This paper presents a method about amorphous obstacles avoidance for local path planning in the two-dimensional sensor environment. In particular, the proposed method is extended from some of the recent studies about a point obstacle avoidance. In the paper, repulsive forces of two types are proposed in order that the robot avoids from the amorphous obstacle with various size and form. A judgment of curvatures in the proposed method simplifies the recognition of obstacles to make the path-planning efficient. In addition, the line of sight(LOS) and the range of recognition are considered in the environment. By simulation results, the proposed method for amorphous obstacle avoidance shows better performance than the related existing method and we confirmed advantages of proposed method.

• Polymer(Korea)
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• v.35 no.4
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• pp.325-331
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• 2011

Molecular simulations via the molecular dynamics method have been carried out to an equation of state of penetrable-sphere model fluids over a wide range of packing fraction ${\phi}$ and finite repulsive energy ${\varepsilon}^*$. The resulting simulation data are compared to theoretical predictions from the two limiting cases of high- and low-penetrability approximations available in the literature. A good agreement between theoretical and simulation results is observed ill the case of ${\varepsilon}^*$ <3.0. However, for the highly repulsive energy systems of ${\varepsilon}^*{\geqq}3.0$, where the potential energy barrier is more than two times higher than the particle kinetic energy, a poor agreement is found due to the clustering formation and the non-continuum size effects in the dense systems of ${\phi}{\geqq}0.7$ and ${\varepsilon}^*$=6.0.

• Journal of Ocean Engineering and Technology
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• v.38 no.4
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• pp.187-198
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• 2024

Autonomous underwater vehicles (AUVs) have a limited bandwidth for real-time communication, limiting rapid responses to unexpected obstacles. This study addressed how AUVs can navigate to a target without a pre-existing obstacle map by generating one in real-time and avoiding obstacles. This paper proposes using forward-looking sonar with an occupancy grid map (OGM) for real-time obstacle mapping and a potential field algorithm for avoiding obstacles. The OGM segments the map into grids, updating the obstacle probability of each cell for precise, quick mapping. The potential field algorithm attracts the AUV towards the target and uses repulsive forces from obstacles for path planning, enhancing computational efficiency in a dynamic environment. Experiments were conducted in coastal waters with obstacles to verify the real-time obstacle mapping and avoidance algorithm. Despite the high noise in sonar data, the experimental results confirmed effective obstacle mapping and avoidance. The OGM-based potential field algorithm was computationally efficient, suitable for single-board computers, and demonstrated proper parameter adjustments through two distinct scenarios. The experiments also identified some of challenges, such as dynamic changes in detection rates, propulsion bubbles, and changes in repulsive forces caused by sudden obstacles. An enhanced algorithm to address these issues is currently under development.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.5_6
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• pp.202-213
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• 2007

A network is an important model widely used in natural and social science as well as engineering. To analyze these networks easily it is necessary that we should layout the features of networks visually. These Graph-Layout researches have been performed recently according to the development of the computer technology. Among them, the Scale-free Network that stands out in these days is widely used in analyzing and understanding the complicated situations in various fields. The Scale-free Network is featured in two points. The first, the number of link(Degree) shows the Power-function distribution. The second, the network has the hub that has multiple links. Consequently, it is important for us to represent the hub visually in Scale-free Network but the existing Graph-layout algorithms only represent clusters for the present. Therefor in this thesis we suggest Graph-layout algorithm that effectively presents the Scale-free network. The Hubity(hub+ity) repulsive force between hubs in suggested algorithm in this thesis is in inverse proportion to the distance, and if the degree of hubs increases in a times the Hubity repulsive force between hubs is ${\alpha}^{\gamma}$ times (${\gamma}$??is a connection line index). Also, if the algorithm has the counter that controls the force in proportion to the total node number and the total link number, The Hubity repulsive force is independent of the scale of a network. The proposed algorithm is compared with Graph-layout algorithm through an experiment. The experimental process is as follows: First of all, make out the hub that exists in the network or not. Check out the connection line index to recognize the existence of hub, and then if the value of connection line index is between 2 and 3, then conclude the Scale-free network that has a hub. And then use the suggested algorithm. In result, We validated that the proposed Graph-layout algorithm showed the Scale-free network more effectively than the existing cluster-centered algorithms[Noack, etc.].

• International Journal of Control, Automation, and Systems
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• v.1 no.3
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• pp.301-307
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• 2003

A control system design based on coupled nonlinear oscillators (CNOs) for a self- organized swarm system is presented. In this scheme, agents self-organize to flock and arrange group formations through attractive and repulsive forces among themselves using CNOs. Virtual agents are also used to create richer group formation patterns. The objective of the swarm control in this paper is to follow a moving target with a final group formation in the shortest possible time despite some obstacles. The simulation results have shown that the proposed scheme can effectively construct a self-organized multi-agent swarm system capable of group formation and group immigration despite the emergence of obstacles.