• Structural Engineering and Mechanics
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• v.76 no.3
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• pp.325-336
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• 2020

In this study, the continuous and discontinuous contact problems of functionally graded (FG) layer resting on a rigid foundation were considered. The top of the FG layer was loaded by a distributed load. It was assumed that the shear modulus and the density of the layer varied according to exponential functions along the depth whereas the the Poisson ratio remained constant. The problem first was solved analytically and the results were verified with the ones obtained from finite element (FE) solution. In analytical solution, the stress and displacement components for FG layer were obtained by the help of Fourier integral transform. Critical load expression and integral equation for continuous and discontinuous contact, respectively, using corresponding boundary conditions in each case. The finite element solution of the problem was carried out using ANSYS software program. In continuous contact case, initial separation distance and contact stresses along the contact surface between the FG layer and the rigid foundation were examined. Separation distances and contact stresses were obtained in case of discontinuous contact. The effect of material properties and loading were investigated using both analytical and FE solutions. It was shown that obtained results were compatible with each other.

• Advances in Computational Design
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• v.2 no.2
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• pp.133-146
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• 2017

This study aimed to investigate the effect of initial member length an imperfection in the load carrying capacity of double-layer domes space structures. First, for the member length imperfection of each member, a random number is generated from a normal distribution. Thereupon, the amount of the imperfection randomly varies from one member to another. Afterwards, based on the Push Down analysis, the collapse behavior and the ultimate capacity of the considered structure is determined using nonlinear analysis performed by the OpenSees software and this procedure is repeated numerous times by Monte Carlo simulation method. Finally, the reliability of structures is determined. The results show that the collapse behavior of double-layer domes space structures is highly sensitive to the random distribution of initial imperfections.

• Journal of the Semiconductor & Display Technology
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• v.19 no.1
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• pp.93-96
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• 2020

Polyimide thin film was prepared by annealing the polyamic acid that was synthesized through co-deposition of diamine and dianhydride. The polyamic acid and polyimide thin film were characterized with FT-IR and HR FE-SEM. The average roughness of the film surface, evaluated with AFM, were 0.385 nm and 0.299 nm after co-deposition, and annealing at 120 ℃ respectively. OLED was passivated with the polyimide layer of 200 nm thickness. While the inorganic passivation layer enhances the WVTR of OLED, the organic passivation layer gives flexibility to the OLED. The in-situ passivation of OLED with organic thin film layer provides the leading technique to develop flexible OLED Display.

• Transactions on Electrical and Electronic Materials
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• v.18 no.3
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• pp.144-147
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• 2017

In this study, two- and three-layer ceramic piezoelectric actuators were designed and simulated according to SUS316 thickness, actuator width, and mass using ATILA software in order to develop a piezoelectric actuator for haptic application. Numerical modelling based on the finite element method was performed to find the resonance frequencies and modal shapes of the actuator. The resonance frequency was affected by the thickness of the SUS316 plate and mass. On the other hand, the width of the actuator did not have a significant impact. Maximum displacements were generated at the center of a haptic three-layer ceramic piezoelectric actuator. The two-layer ceramic piezoelectric actuator with a mass of 2.6 g was suitable as $16.28{\mu}m$ at 265 Hz for haptic sensation application.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.474-479
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• 2005

Experimental and theoretical studies of internal cavity pressure during injection molding of a spiral tube cavity were carried out. The frozen layer thickness and the evolution of internal cavity pressure were calculated using a commercial software (C-MOLD). The evolution of the internal cavity pressure was recorded during injection molding of polystyrene into a spiral tube mold. To explain the differences observed between the calculated and measured internal cavity pressure, a pressure correction factor (PCF) was introduced based on the plane stress theory. This factor was determined by analyzing the stress state in the melt and calculating the frozen layer thickness near the mold wall. The corrected and experimental pressures have been compared to validate the applicability of the pressure correction factor.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.3
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• pp.51-61
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• 2010

Nowadays, there are various networked systems with many computers. In most networked systems, a crucial objective is to keep transmitting and/or receiving data continuously even though failures exist. How can one make a computer continue transmitting and/or receiving data even when there are some errors on a link? Fault-Tolerant Ethernet (FTE) can be a solution to this question. In this paper, we propose a Localized Software-based Fault-Tolerant Ethernet (LSFTE). Our new approach fulfills the general FTE requirements. It takes advantage of redundant cable lines to maintain communication in a faulty environment. A software layer, which uses a simple and effective algorithm, is added above the LAN card driver software to detect and overcome faults. For our approach, there is no need to change the existing hardware or the end-use interfaces. Furthermore, the fault-detection time is reduced significantly compared to the conventional software-based approach.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.17-22
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• 2010

As deployments of Flash memory are spreading out rapidly from tiny USB storages to large DB servers, interoperability become an indispensable requirement for Flash memory software architecture. For the purpose, many systems make use of the conventional FAT file system and FTL (Flash Translation Layer) software as a de facto standard. However, the tactless combination of the FAT file system and FTL does not satisfy diverse other requirements of a variety of systems. In this paper, we propose a novel reconfigurable integrated Flash memory software architecture, named INFLAWARE (INtegrated FLAsh softWARE) that supports not only interoperability but also reconfigurability and performance enhancement. Real implementation based experimental results have shown that INFLAWARE can achieve improvements of memory footprint up to 27% with an average of 19%, compared with the conventional FAT and FTL combination. Also, by using map_destroy technique, it can reduce response times of various applications up to 21% with an average of 10%.

• Journal of Advanced Navigation Technology
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• v.14 no.3
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• pp.321-327
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• 2010

This paper deals with the design and development of the motorized valve control system using CANopen protocol. The CAN network protocol is used in the physical layer(layer 1) and data link layer(layer 2), and other upper network layer above that layer 1 and 2 utilize the CANopen protocol in this paper. The motorized valve controller is implemented by a PIC microprocessor, and the server application software for the control system user is written in C# language. In particular the CANopen protocol is widely used int the area such as ship automation systems and marine transportation systems. The experimental result of the proposed control system implemented in this paper is evaluated via real-time experiments, which works well as designed.

• Journal of the Korea Computer Industry Society
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• v.2 no.4
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• pp.481-490
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• 2001

In this paper, we propose the industrial controller with multi-function/multi-purpose in order to cope with a small-amount and large-items environments. The controller designed consists of Main Unit including all of information and Display Unit. The software in the Main Unit is composed of tasks and device drivers and each task is being processed in parallel by operating system supporting multitasking. The controller is structured in three levels to promptly address the control algorithm’s modification, MMI’s change, and so on. We can produce a controller without changing the first layer(hardware) and the second layer(firmware). We only modify the third layer(control algorithm) depending on control targets.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.2
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• pp.154-160
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• 2006

Instantaneous reaction and intelligence are required for autonomous mobile robots to achieve multiple goals in the unpredictable and dynamic environments. Design of the appropriate control architecture and clear definitions of systems are needed to construct and control these robots. This research proposes the hybrid deliberative/reactive control architecture which consists of three layers and uses the method of software structure design. The highest layer, Deliberative Layer makes the overall run-time schedule for navigation and/or manipulation, and the middle layer, Task Execution Layer carries out various missions. The lowest layer, Reactive Layer enables a robot to react rapidly in the dynamic environment and controls the mechanical devices concurrently. This paper proposes independent system supervisors called Manager to reuse the modules so that the Manager supports common use of the system and multi-processing tasks. It is shown that the mobile robot based on the proposed control scheme can perform the basic navigation and cope with the dynamic obstacles reasonably well.