• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.9
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• pp.2202-2217
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• 2012

The transmission opportunities between nodes in Delay Tolerant Network (DTNs) are uncertain, and routing algorithms in DTNs often need nodes serving as relays for others to carry and forward messages. Due to selfishness, nodes may ask the source to pay a certain reward, and the reward may be varying with time. Moreover, the reward that the source obtains from the destination may also be varying with time. For example, the sooner the destination gets the message, the more rewards the source may obtain. The goal of this paper is to explore efficient ways for the source to maximize its total reward in such complex applications when it uses the probabilistic two-hop routing policy. We first propose a theoretical framework, which can be used to evaluate the total reward that the source can obtain. Then based on the model, we prove that the optimal forwarding policy confirms to the threshold form by the Pontryagin's Maximum Principle. Simulations based on both synthetic and real motion traces show the accuracy of our theoretical framework. Furthermore, we demonstrate that the performance of the optimal forwarding policy with threshold form is better through extensive numerical results, which conforms to the result obtained by the Maximum Principle.

• Journal of Magnetics
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• v.14 no.2
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• pp.66-70
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• 2009

The dynamic magneto-mechanical behaviors in a type of iron-nickel-based ferromagnetic alloy with constant elasticity were investigated as a function of both the DC bias magnetic field ($H_{dc}$) and the frequency. The rectangular plate-like samples were excited to vibrate at a half-wavelength, longitudinal resonance by an AC magnetic field superimposed with various $H_{dc}$. The experimental results found that the strain coefficient at resonance reached 819.34 nm/A and the effective mechanical quality factor ($Q_m$) was greater than 2000. The ratio of the maximum variation of the Young's modulus over $H_{dc}$ to the value of the Young's modulus at a zero bias field was only ${\sim}0.83%o$ because of the so-called constant elasticity. The resonant strain coefficients and $Q_m$ are strongly dependent on $H_{dc}$, which indicates a promising potential for use in DC and quasistatic magnetic field sensing.

• Structural Engineering and Mechanics
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• v.85 no.6
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• pp.781-791
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• 2023

Lateral pressure plays a significant role in the stress-strain relationship of compressed concrete. Concrete's internal cracking resistance, ultimate strain, and axial strength are improved by confinement. This phenomenon influences the nonlinear behavior of reinforced concrete columns. Utilizing behavior factors to predict the nonlinear seismic responses of structures is prevalent in seismic codes, and this factor plays a vital role in the seismic responses of structures. This study aims to evaluate the confining action on the behavior factor of reinforced concrete moment resisting frames (RCMRFs) with shear walls (SWRCMRFs). To this end, a diverse range of mid-rise SW-RCMRFs was initially designed based on the Iranian national building code criteria. Second, the stress-strain curve of each element was modeled twice, both with and without the confinement phenomenon. Each frame was then subjected to pushover analysis. Finally, the analytical behavior factors of these frames were computed and compared to the Iranian seismic code behavior factor. The results demonstrate that confining action increased the behavior factors of SW-RCMRFs by 7-12%.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.10
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• pp.837-842
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• 2005

The computational modeling and simulation of complex biological systems are indispensable for new knowledge extraction from huge experimental data and ever growing vast amount of information in systems biology. Moreover, gathering and sharing of the existing information and newly-generated knowledge can speed up this research process. In this regard, several modeling projects have been undertaken for quantitatively analyzing the biological systems via the internet. They include Virtual Cell, JWS and OBIYagns. We also develop an integrated web-based environment, which facilitate investigation of dynamic behavior of cellular systems.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.312.1-312.1
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• 2008

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.2
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• pp.91-93
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• 2000

Insects have many excellent features and functions in their small bodies, such as hexapod walking, flapping flight, vision systems, sensory hairs, etc, and those characteristics can be thought as good models for many types of robots. Insects also will be good models far micro-machines because of its size. Insect behavior consists of simple reflex acts and programmed behavior, Some robots were made in order to clarify the emergent mechanism of insect behavior, Through some experiments it would be found that even if insect behavior consists of some simple action patterns, it looks intelligent through interactions its sensors and actuators with its complex environment. In the near futures small robots inspired by insects will be used in many fields of our life. I hope that insect-model based robots will play an active part in many fields and that they will make us happy.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.101-106
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• 2005

In this paper, we propose a behavior decision model for a robot, which is based on artificial emotion, various motivations and dynamic personality. Our goal is making a robot which can express its emotion human-like way. To achieve this goal, we applied several emotion and personality theories in psychology. Especially, we introduced the concept of dynamic personality model for a robot. Drawing on this concept, we could make a behavior decision model so that the emotion expression of the robot has adaptability to various environments through interactions between human and the robot.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.134-141
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• 2023

As robotic technology expands into various fields, robots need to execute some complicated tasks in diverse environments. However, the previous robotic software solutions were limited to independent systems. We can not adapt to diverse functionalities and environments. This makes it hard to provide rapid and effective services and leads to costs and losses in the development process. To overcome these problems, we propose a robot software framework with behavior trees based on ROS2. This framework simplifies complex robot behaviors through behavior trees and makes it easy to modify, extend, and reuse robot behaviors. Furthermore, ROS2 standardizes connections between software modules, enhances the robot's flexibility, and enables independent development and testing of software. Our framework aims to provide a foundation for high-quality robot service provision by supporting the modularity, reusability, independent development, and testing required by intelligent robots that need to provide services in various environments.

• 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.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.8
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• pp.96-103
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• 2008

In this study, we performed the biomechanical analysis of cervical plate systems by using a computer simulation based on finite element method to derive reliable model by analysis of design variables and fatigue behavior. To simulate the cervical spine movement in-vivo state by surgery, we modeled the cervical plate system which consisted of screws, rings, rivets, and plate and Ultra High Molecular Weight Polyethylene (UHMWPE) Block. The experiment of cervical plate system followed the ASTM F1717 standards that covered the materials and methods for the static and fatigue testing. The result of computer simulation is compared with experimented test. We expected this study is to derive reliable results by analysis of design variables and fatigue behavior for developing a new model.