• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.2
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• pp.200-207
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• 2009

Complex systems are made of many subsystems, those are developed and manufactured by many part companies. Even though the information for a part is necessary to analyze the performance of the other part, it is not so easy to get the information for that part from other companies due to many reasons like security or compatibilities. If the modal parameters of a system between the connecting points are available, we can reconstruct a reduced model for that system in a physical coordinate not in a generalized coordinate. The assemble of the equations of motion for the main system and the reduced equations of motion for the connected system can give a response of the main system considering the effects of connected systems. The results show that the proposed method can give the response of a system accurately. The rule for the selection of modes is to use the fundamental modes whose natural frequencies are low.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.7
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• pp.1604-1618
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• 1995

In the process of mechanical assembly design, assembly modeling systems have been used mainly for the design verification before manufacturing by enabling to check the interference and/ or the dynamic and kinematic performance. However, the conventional assembly modeling systems have a shortcoming that they can not be used in the initial design stage but can be used only after the design is fully completed. In other words conventional assembly modeling systems provide bottom-up modeling which means that the detailed modeling of components must precede the definition of relationships between them. To resolve this problem, an assembly modeling system is proposed to provide a top-down modeling environment in which components and assembly can be modeled simultaneously. To this end, an assembly data structure suitable for top-down assembly modeling has been established. Feature positioning Module(FPM) using geometric constraints has been also developed. The Sekective Solving Method proposed for FPM is based on the priority between the constraint equations and enables the designer's intent expressed by geometric constraints to be maintained throughout the whole modeling process. Finally, the feature based modeling technique using two-level features has been developed. Two-level features include an abstract model and a detailed model in a merged form in non-manifold data frame.

• Computers and Concrete
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• v.13 no.5
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• pp.587-601
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• 2014

A sophisticated finite element modeling approach is proposed to simulate unbonded post-tensioned concrete slabs. Particularly, finite element contact formulation was employed to simulate the sliding behavior of unbonded tendons. The contact formulation along with other discretizing schemes was selected to assemble the post-tensioned concrete system. Three previously tested unbonded post-tensioned two-way and one-way slabs with different reinforcement configurations and boundary conditions were modeled. Numerical results were compared against experimental data in terms of global pressure-deflection relationship, stiffness degradation, cracking pattern, and stress variation in unbonded tendons. All comparisons indicate a very good agreement between the simulations and experiments. The exercise of model validation showcased the robustness and reliability of the proposed modeling approach applied to numerical simulation of post-tensioned concrete slabs.

• Journal of the Semiconductor & Display Technology
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• v.16 no.3
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• pp.59-64
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• 2017

As the demand on displays increases, new thin-film transistors such as metal oxide transistor are continuously being invented. When designing a circuit consisting of such new transistors, a new transistor model based on proper charge transport mechanisms is needed for each of them. In this paper, a modeling framework which enables to choose charge transport mechanisms that are limited to certain operation regions and assemble them into a transistor model instead of making an integrated transistor model dedicated to each transistor. The framework consists of a graphic user interface to choose charge transport models and a current calculation part, which is also implemented in AIM-SPICE for circuit simulation.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.4
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• pp.458-463
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• 2011

A CHS(Container Handling System) is a system to load and to unload ISO 2000 or ISO 4000 standard containers which is widely used for various industrial transport purpose. A new light type of CHS is introduced in this paper, in order to reduce weight of cargos and to give the convenience in cargo loading and unloading without additional lifting equipments. The structural models of this system are created to assemble the smooth integration of system and to interface the each composing units with the specification of truck chassis to be mounted. These models are applied to find the suitable design parameters under the condition of force restrictions of each units. Finally, the stability of this system are investigated by analyzing the dynamic simulation using Visual NASTRAN 4D, and it could be recommend the good design parameters for the manufacturing purpose.

• Journal of information and communication convergence engineering
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• v.12 no.1
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• pp.46-52
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• 2014

This article presents key research needs in three-dimensional integrated circuit (3D IC) architectural floorplanning. Architectural floorplaning is done at a very early stage of 3D IC design process, where the goal is to quickly evaluate architectural designs described in register-transfer level (RTL) in terms of power, performance, and reliability. This evaluation is then fed back to architects for further improvement and/or modifications needed to meet the target constraints. We discuss the details of the following research needs in this article: block-level modeling, through-silicon-via (TSV) insertion and management, and chip/package co-evaluation. The goal of block-level modeling is to obtain physical, power, performance, and reliability information of architectural blocks. We then assemble the blocks into multiple tiers while connecting them using TSVs that are placed in between hard IPs and inside soft IPs. Once a full-stack 3D floorplanning is obtained, we evaluate it so that the feedback is provided back to architects.

• Journal of Mechanical Science and Technology
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• v.17 no.9
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• pp.1268-1275
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• 2003

In this paper, a compact 3-DOF mobile microrobot with sub-micron resolution is presented. It has many outstanding features : it is as small as a coin ; its precision is of sub-micrometer resolution on the plane ; it has an unlimited travel range ; and it has simple and compact mechanisms and structures which can be realized at low cost. With the impact actuating mechanism, this system enable both fast coarse motion and highly precise fine motion with a pulse wave input voltage controlled. The 1 -DOF impact actuating mechanism is modeled by taking into consideration the friction between the piezoelectric actuator and base. This modeling technique is extended to simulate the motion of the 3-DOF mobile robot. In addition, experiments are conducted to verify that the simulations accurately represent the real system. The modeling and simulation results will be used to design the model-based controller for the target system. The developed system can be used as a robotic positioning device in the micromanipulation system that determines the position of micro-sized components or particles in a small space, or assemble them in the meso-scale structure.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.467-475
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• 2015

In this paper, the FREECAD 0.14 was used for modeling conventional Selfie-stick and the newly proposed Selfie-stick design. The purpose of this paper is to demonstrate the utility of FREECAD 0.14, which is open-source and still in development for further use. After modeling the conventional Selfie-stick, CatiyaV5 was used to assemble FREECAD 0.14 drawn elements. Main advance in newly designed Selfie-stick is the portability. To improve portability of the Selfie-stick, folding mechanism was adopted from folding LED stands. Several mechanisms were adopted to improve user convenience as well. Ansys 14.0 was used for structural analyses of conventional Selfie-stick model and the newly designed model as well. Several simplifications for the models were needed to process the analyses. When analyzing the newly designed model various materials were used one by one to find compatible composition. Using Aluminum alloys for the stick and the hand grip was found to be compatible. FREECAD was useful for suggestion of the newly designed model but not so much useful to design an actual product. Various efforts would make FREECAD the best choice for industrial use for free as it is named.

• CDE review
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• v.21 no.2
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• pp.61-64
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• 2015

In this paper, the FREECAD 0.14 was used for modeling conventional Selfie-stick and the newly proposed Selfie-stick design. The purpose of this paper is to demonstrate the utility of FREECAD 0.14, which is open-source and still in development for further use. After modeling the conventional Selfie-stick, CatiyaV5 was used to assemble FREECAD 0.14 drawn elements. Main issue in newly designed Selfie-stick is the portability. To improve portability of the Selfie-stick, folding mechanism was adopted from folding LED stands. Several mechanisms were adopted to improve user convenience as well. Ansys 14.0 was used for structural analyses of conventional Selfie-stick model and the newly designed model as well. Several simplifications for the models were needed to process the analyses. When analyzing the newly designed model various materials were used one by one to find compatible composition. Using Magnesium Alloy for the stick and the hand grip was found to be compatible. FREECAD was useful for suggestion of the newly designed model but not so much useful to design an actual product. Various efforts would make FreeCAD the best choice for industrial use for free as it is named.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.1
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• pp.11-23
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• 2015

In this study, the new segment assembling method using cable tensible force was developed to improve the problem of bolt assembling method of shield tunnel. In the field test construction, cable assembling method reduced the assembling time of segment in comparison with bolt assembling method because of guide role of segment shear-key. In the result of measuring the necessary time for segment assembling process, it took 420sec to assemble one segment in bolt method and 400sec to assemble one segment in cable method, but in case of using the cable automatic feeder, it could reduce the necessary time as 60sec in comparison with bolt assembling method. The cable automatic system modeling using BIM, that connected shield TBM also will be utilized in the area of design TBM, excavation plan, method process understanding, construction management and so on.