• Proceedings of the KWS Conference
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• 2002.10a
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• pp.314-319
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• 2002

The Automation and Control Group at the University of Brasilia is developing an automatic welding station based on an industrial robot and a controllable welding machine. Several techniques were applied in order to improve the quality of the welding joints. This paper deals with the implementation of a laser-based computer vision system to guide the robotic manipulator during the welding process. Currently the robot is taught to follow a prescribed trajectory which is recorded a repeated over and over relying on the repeatability specification from the robot manufacturer. The objective of the computer vision system is monitoring the actual trajectory followed by the welding torch and to evaluate deviations from the desired trajectory. The position errors then being transfer to a control algorithm in order to actuate the robotic manipulator and cancel the trajectory errors. The computer vision systems consists of a CCD camera attached to the welding torch, a laser emitting diode circuit, a PC computer-based frame grabber card, and a computer vision algorithm. The laser circuit establishes a sharp luminous reference line which images are captured through the video camera. The raw image data is then digitized and stored in the frame grabber card for further processing using specifically written algorithms. These image-processing algorithms give the actual welding path, the relative position between the pieces and the required corrections. Two case studies are considered: the first is the joining of two flat metal pieces; and the second is concerned with joining a cylindrical-shape piece to a flat surface. An implementation of this computer vision system using parallel computer processing is being studied.

• International conference on construction engineering and project management
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• 2017.10a
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• pp.301-312
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• 2017

Quality evaluation and control represent increasingly important concerns for construction quality management. There is an evident need for a standard data model to be used as the basis for computer-aided quality management. This study focuses on how to realize evaluation of construction quality based on BIM and database technology. In this paper, the reinforced concrete main structure is taken as an example, and the BP neural network evaluation model is established by inquiring current construction quality acceptance specification and evaluation standard. Furthermore, IFC standard is extended to integrate quality evaluation information and realize the mapping of evaluation information in BIM model, contributing to the visualization and transfer sharing of evaluation information. Furthermore, the conceptual entity model is designed to build quality evaluation database, and this paper select MySQL workbench system to achieve the establishment of the database. This study is organized to realize the requirement of visualization and data integration on construction quality evaluation which makes it more effective, convenient, intuitive, easy to find quality problems and provide more comprehensive and reliable data for the quality management of construction enterprises and official construction administratiors.

• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.15-22
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• 2003

In the conventional load transfer analysis for a steel pipe drilled shaft, it was assumed that the concrete's strain is the same as the measured steel's strain and the elastic modulus of the steel and the concrete calculated by the formular as prescribed by specification is used in the calculation of pile axial load. But, the pile axial load calculation by conventional method differed to some extent from the actual pile load. So, the behavior of a steel pipe drilled shaft could not be analyzed exactly. Thus, the necessity to measure the strain for each pile component was proposed. In this study, a new approach for load transfer measurement of large diameter drilled shafts was suggested ; the strain of each pile component(i. e., steel and concrete) was measured by DRS(Deformable Rod Sensor), the elastic modulus was determined by the uniaxial compression test for concrete specimens made at test site and a value of elastic modulus was evaluated as average tangential modulus corresponding to the stress level of the (0.2-0.6)$f_{ck}$. Field application was confirmed by the results of load transfer measurement tests for 3 drilled shafts. The errors for calculated pile head load were -11 ∼16% and 3.4% separately.

• Journal of the Korea Society for Simulation
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• v.17 no.2
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• pp.21-29
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• 2008

The High Level Architecture(HLA) specifies a framework for interoperation between heterogeneous simulators, and Run-Time Infrastructure(RTI) is a implementation of the HLA Interface Specification. The Data Distribution Management(DDM) services, one category of IEEE 1516 HLA/RTI management services, control filters for data transmission and reception of data volume among simulators. In this paper, we propose design concept of DDM and show its implementation for light-weighted RTI. The design concept of DDM is to minimize total amount of message that each federate and a federation process generate using the rate of RTI service execution. The design of our proposed DDM follows that a data transfer mechanism is differently applied as the rate of RTI service execution. A federate usually publishes or subscribes data when it starts. The federate constantly updates the data and modifies associated regions while it continues to advance its simulation time. Therefore, the proposed DDM design provides fast update or region modification in exchange of complex publish and subscribe services. We describe how to process the proposed DDM in IEEE 1516 HLA/RTI and experiment variable scenarios while modifying region, changing overlap ratio, and increasing data volume.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.300-305
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• 2007

In this study, we have studied the fabrication and the performance evaluation of digital radiation detector of the based on selenium (a-Se) prototype which is widely researched about recently. The detector was fabricated using amorphous selenium in the specification of active area size $7{\times}8.5"$, pixel pitch $139{\mu}m$, and 12 bit ADC. In order for the performance evaluation of the fabricated detector, we used radiation quality RQA 5 that is suggested by the International Electrotechnical Commission (IEC), and evaluated modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE). Concerning MTF measurement, we used slit camera (Nuclear Associates, Model : 07-624-2222), and evaluated in the slit method. Also so as to compare the performance evaluation on the detector fabricated in this study, we used Hologic Direct-Ray (DR-1000) and GE Revolution XQ/I system, and evaluated and compared in the same method MTF, NPS, and DQE which are image quality factors. And as a result, the MTF of each detector In Nyquist frequency were evaluated to be 58% (at 3.5 lp/mm) in the case of DR-1000 and 65% (at 2.5 lp/mm) in the case of XQ/I, and that for the detector fabricated in this study was evaluated to be 36% (at 3.51 lp/mm). Also in the case of DQE(0), the detector fabricated in this study, DR-1000 of Hologic company, and XQ/I system of GE company respectively were evaluated as 36%, 32%, and 50%.

• Journal of Korea Multimedia Society
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• v.2 no.4
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• pp.476-489
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• 1999

HW/SW codesign is integrated design of systems implemented using both hardware and software components. Many design tools has been developed to support this new paradigm, so far. Current codesign tools are not widely used as been expected because of variety problems - rapidly evolving technology, platform dependency, absence of standard specification method, inconsistent user interface, varying target system, different functionality In this paper, we propose a web-based distributed HW/SW codesign environment to remedy this kinds of problem. Our codesign environment has object-based 3 tier client/server architecture. It supports collaborative workspace through session service. Fully object-oriented design of user interface(OOUI) enables easy extension without change of user Interface. Furthermore it contains transaction server and security server for efficient and safe transfer of design data. To show a validity of our design, we developed prototype of web-based HW/SW codesign environment called WebCEDA. Our model of HW/SW codesign can be used for web-based generic CAD tools.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.5
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• pp.545-552
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• 2015

The heat generation in PEMFC is proportional to the electrical power output. Therefore, when the fuel cell produced the maximum output, the maximum heat was generated. In order to maintain the performance of the fuel cell, thermal management is as important as pressure and humidity conditions of the reactive gas. In this study, considering the thermal management for the maximum output operation, the optimal cooling channel design specifications of bipolar plate are found for the highest cooling performance. In the current bipolar plate research, many studies focused on analyzing various factors individually but there is no more study on the interaction between design factors. In this study, the heat transfer was simulated by COMSOL Multiphysics with the main design factors which are designated shape, width and rib length. One of the experimental design methods, general full factorial design method, was used to analyze the main factor and interaction on average temperature and maximum temperature for the design specification of fuel cell bipolar plate. When analysis result shows that all of these three factors are highly important, it can confirm that the interaction occurs between the factors.

• Journal of the Korean Geotechnical Society
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• v.19 no.5
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• pp.35-47
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• 2003

In the conventional axial load transfer analysis for composite piles (i.e., steel pipe pile filled with concrete), it was assumed that the concrete's strain is same as the measured steel's strain and the elastic modulus of the steel and the concrete calculated by formular as prescribed by specification is used in calculation of pile axial load. But, the pile axial load calculated by conventional method had some difference with the actual pile load. So, the behavior of a composite pile could not be analyzed exactly. Thus, the necessity to measure the strain for each pile components was proposed. In this study, the verification test for DRS (Deformable Rod Sensor) developed to measure the strain of each pile component (i.e., the steel and the concrete) was performed. In the calculation of pile axial load using the DRS, elastic modulus of concrete could be determined by the uniaxial compression test for the concrete cylinder samples made in the test site and an average tangential modulus in the stress range of (0.2∼0.6)f$_ck$ was taken.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.3
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• pp.545-550
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• 2016

The main purpose of this study is to analyze and evaluate the feasibility of ligthweight pavement system with pile foundation on soft soil by laboratory small chamber test. In order to verify the stability of lightweight pavement system, the 1/30 scaled downed model system was tested at lab. The soft soil condition was simulated and group piles for skin friction resistance were used. Within the limited lab test, the settlements of pavement system were 0.86 mm for Case A, 0.70 mm for Case B, and 0.50 mm for Case C. The converted maximum settlement differential settlement were 25.8 mm and 10.8 mm. These values meet the inside of specification of Bridge Design Guide in Korea. The use of lightweight pavement systems on soft soils could be an alternative construction method on soft soils to reduce the challenges of conventional design and constructions.

• Journal of Korean Society for Geospatial Information Science
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• v.6 no.2 s.12
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• pp.81-90
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• 1998

With the high demand for Geographic Information System and the diversification of Spatial Information, it has been required a rapid and accurate input system, updating system and an efficient field survey system to organize database for thematic mapping. Following the purpose, several indispensable modules have to be Invented to build a GPS Lap-top Computer System using low cost GPS receivers. These modules include such as an interface module between GPS receivers and lap-top computers, a data processing module for standalone GPS or Real-time Differential GPS, a module to input or amend digital map and to transfer three-dimensional coordinates in real-time, and finially a module to enter attribute value and feature code based on standard specification of digital maps for controlling position and attribute data. In this paper, it Is presented the efficiency of method to acquire and to input or to amend spatial information using a GPS Lap-top Computer System.