• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1998.03a
• /
• pp.155-159
• /
• 1998

This paper describes a research work of developing a computer-aided design and manufacturing (CAD-CAM) of irregular shaped sheet metal product for blanking or piercing and bending operation. An approach to the system is based on the knowledge-based rules. Knowledge for the system is formulated form plasticity theories, experimental results and the empirical knowledge of field experts. This system has been written in AutoLIST on the AutoCAD and in customer tool kit on the SmartCAM with a personal computer and is composed of nine modules. the system is designed by considering several factors, such as material and thickness of product, complexities of blank geometry and punch profile, diameter and material of a wire, and availability of press. This system is capable of unfolding a formed sheet metal to give flat pattern and automatically account for the adjustment of bending allowances to match tooling requirements by checking dimensions and generating NC data automatically according to drawings of die-layout module. Results carried out in each module will provide efficiencies to the designer and the manufacture of blanking or piercing and bending die in this field.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.160.2-160.2
• /
• 2014

Recently silicon has attracted intense interest as a promising anode material of lithium-ion batteries due to its extremely high capacity of 4200 mA/g (for Li4.2Si) that is much higher than 372 mAh/g (for LiC6) of graphite. However, it seriously suffers from large volume change (even up to 300%) of the electrode upon lithiation, leading to its pulverization or mechanical failure during lithiation/delithiation processes and the rapid capacity fading. To overcome this problem, Si nanowires have been considered. Use of such Si nanowires provides their facile relaxation during lithiation/delithiation without mechanical breaking. To design better Si electrodes, a study to unveil atomic-scale mechanisms involving the volume expansion and the phase transformation upon lithiation is critical. In order to investigate the lithiation mechanism in Si nanowires, we have developed a reactive force field (ReaxFF) for Si-Li systems based on density functional theory calculations. The ReaxFF method provides a highly transferable simulation method for atomistic scale simulation on chemical reactions at the nanosecond and nanometer scale. Molecular dynamics (MD) simulations with the ReaxFF reproduces well experimental anisotropic volume expansion of Si nanowires during lithiation and diffusion behaviors of lithium atoms, indicating that it would be definitely helpful to investigate lithiation mechanism of Si electrodes and then design new Si electrodes.

• Transactions of Materials Processing
• /
• v.7 no.6
• /
• pp.554-561
• /
• 1998

This paper describes a research work of developing a computer-aided design of lead frame semicon-ductor with piercing operation which is very precise for progressive working. An approach to the sys-tem is based on to knowledge-based rules. Knowledge for the system is formulated from plasticity theories experimental results and the empirical knowledge of field experts. This system has been writ-ten using AutoLISP to AutoCAD on a personal computer and is composed of three main modules which are input and shape treatment production feasibility check and strip-layout module. Based on the knowledge-based rules the system is designed by considering several factors such as material and thickness of product complexities of blank geometry and punch profile, and availability of press. Also strip-layout drawing generated by piercing operation according to punch profiles considered V-notch dimple. pad chamfer spank cavity punch camber and cross bow of lead frame is displayed in graphic forms. This system can be used by a novice who may not have any knowledge of tool design and will invrease efficiencies to the designer in this field.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.26 no.2
• /
• pp.177-183
• /
• 2002

The field tests on the waterhammer were carried out in the pump pipeline system with an air chamber. The effects of the input variables and the design parameters for the air chamber were investigated by both the numerical calculations and the experiments. Because the waterhammer problems as a result of the pump power failure were the most important, these situations were carefully studied. Among the input variables used in the waterhammer analysis, the polytropic exponent, the discharge coefficient and the wavespeed had influence on the simulated results in that order, and were calibrated in comparison with the experimental results. As the initial air volume in a vessel increased, the period of waterhammer increased and the pressure variation decreased, resulting from the reduction of the rate of pressure change in the air chamber. Using smaller orifice in the bypass pipe, the pressure rise was suppressed in some degree and the pressure surge was dissipated more rapidly as time passed. The simulations were in fairly good agreement with the measured values until 1∼2 periods of waterhammer. Not only the maximum and minimum pressures in the pipe1ine but also those occurring times were reasonably predicted. The computer program developed in this study will be useful in designing the optimum parameters of an air chamber for the real pump pipeline system.

• Korean Institute of Interior Design Journal
• /
• v.22 no.3
• /
• pp.100-107
• /
• 2013

In smart era, concept of User experience has been an important issue both in academic and practical areas in recent years. Interactive space became one of the major design paradigms. For elevating the interactive effect, we need user?centered design methodology which uses the influential factors on the interactivity. As, well developed information technology made a lot of changes to various fields of our society, interactive space with the concept of HCI became a big issue in environmental design field. In this interactive space, various types of informative factors of the given space are sent using sensor and computer networking technology to the main system. So, a user's movement in the space in more than just a movement itself-user's movement now forms a important spatial structure that leads the narrative of the space. in this research, I will come up with the problems that the interactive space has right now, and analyze what the public space must have, and combine them with interactive space by HCI theory. architecture space is not the old space adapting digital technology. In order to take the role as new space paradigm. environment and technology, it has to develop technology continuously and experimental space at the same time. It must have co-evolution of architecture space field and others through organic network. by that, the evolution of space will be in the way that combines space which is responded to human emotion and user centric human friendly.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.46 no.4
• /
• pp.102-110
• /
• 2009

In this paper, we propose an object detection method for real-time in infrared (IR) images and PowerPC (PPC) and H/W design based on field programmable gate array (FPGA). An open H/W architecture has the advantages, such as easy transplantation of HW and S/W, support of compatibility and scalability for specification of current and previous versions, common module design using standardized design, and convenience of management and maintenance. Proposed background modeling for an open H/W architecture design decreases size of search area to construct a sparse block template of search area in IR images. We also apply to compensate for motion compensation when image moves in previous and current frames of IR sensor. Separation method of background and objects apply to adaptive values through time analysis of pixel intensity. Method of clutter reduction to appear near separated objects applies to median filter. Methods of background modeling, object detection, median filter, labeling, merge in the design embedded system execute in PFC processor. Based on experimental results, proposed method showed real-time object detection through global motion compensation and background modeling in the proposed embedded system.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.774-777
• /
• 2001

This paper describes a research work of developing a computer-aided design system of cold forging products. An approach to the system is based on the knowledge-based rules. Knowledge for the system is formulated from plastic theories, experimental results and the empirical knowledge of field experts. The system has been written in AutoCAD with a personal computer and is composed of six modules, which are selection of billet material, input of final product, process planning design, preform modification, insert design, shrink rings design module. Based on knowledge-based rules, the system is designed by considering several factors such as volume constancy, limite of formability by material, preform shape and so on.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.2
• /
• pp.117-123
• /
• 2005

The cutoff frequency of a LC output filter for Dynamic Voltage Restorers (DVR) limits the control bandwidth of a DVR system while it attenuates the inverter switching ripples. For a selected cutoff frequency of a LC output filter, infinite number of L-C combinations is possible. Although different L-C combination has different filter characteristics, the filter design on L-C combination has been depended on field experiences without clear analysis. This paper proposes a design criterion and design examples for the L-C filter combination considering the control characteristics and the size of DVRs. An experimental DVR system based on the proposed LC output filter design methodology is built and tested.

• Journal of Engineering Education Research
• /
• v.21 no.4
• /
• pp.10-19
• /
• 2018

This study introduces an engineering design class which is experimental in a sense that it is planned and implemented with three key concepts such as learner-centered education, living lab and community based learning. With the class run in being connected with one regional community in Seoul, it focuses on its educational effects acquired through the living lab-based approach. And this research investigates the student's experiences of when, what and how they learn in a learner-centered class. It shows that, rather than taking professor's one dimensional lectures in classroom, the students learn actively when they face with the problem in the field. Students have come to carry out engineering design from the perspective of stakeholders, not from the supplier or producer's perspective in the process of meeting with the problem in reality. Team based collaborative activities are crucial in the entire design process. More importantly, students' design products have been transformed into more useful and meaningful ones as stakeholders of the local community have participated into the students' works. However, we need to recognize that there are some important issues that need to be solved institutionally and systematically in order for such educations to spread. This study suggests several educational arrangements for those issues.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.37 no.1
• /
• pp.1-8
• /
• 2001

This study deals with the experimental and numerical investigations to design the high performance otter board. Experiment was carried out to determine the most effective slot size of single-slot cambered otter board in the circulation water channel of BAEK KYUNG IND. Co. LTD. Numerical analysis was done by the commercial CFD code, FLUENT, to provide some valuable physical interpretations and finally to design the otter board section by numerical method. The major results are as follows ; 1. In experiment, the maximum lift and drag coefficients of simple cambered type otterboard were 1.41, 0.55, respectively, at the angle of attack $28^\circ$, while those of slot one with slot size 0.02C (C denotes the chord length) were 1.72, 0.42 at the angle of attack $24^\circ$. 2. The hydrodynamic characteristics depending upon slot size shows the greatest at 0.02C of the slot size. 3. Numerical results well visualized the streamlines, pressure fields, and speed vectors of a simple cambered and slot cambered otter board with slot size 0.02C. The slot cambered one with slot size 0.02C was shown that pressure field was distributed moderately on front and back side of otter board. And, the delay and decrease of separation were favorably achieved by flow through slot. 4. Computed result on the pattern of hydrodynamic field and the values of $C_L$ and $C_D$ by the commercial CFD code, FLUENT, show almost the same as those of the experimental result.