• International Journal of Precision Engineering and Manufacturing
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• v.6 no.3
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• pp.8-12
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• 2005

The positioning system for an ultra precision machine tool must be accurate to the order of a nanometer. Various feed drive devices have been proposed to achieve this resolution; currently, most attention is directed towards hydrostatic lead screws and friction drives. It has been reported that a positioning resolution accurate to an angstrom can be achieved using a twist-roller friction drive. Therefore, we manufactured an ultra precision positioning system driven by a twist-roller friction drive and assessed its performance when defining problems and finding solutions. Our study showed that the twist-roller friction drive is mechanically suitable for ultra precision positioning, but some considerations are required to obtain a higher resolution.

• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.3
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• pp.22-35
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• 2003

This paper describes system technical requirement development process from operational concept using computer-aided Systems Engineering tool(CASysE Tool-CORE). The army tactical missile system-ATACMS's technical requirements are developed by the process as a case-study The scope of the work is context analysis and requirement definition process. The proposed process is as follows. At first, an integrated architecture could be developed from the operational concept. From the integrated architecture a capability needs, which includes KPPs, are generated. And the capability needs expanded according to the Mil-Std-961D format. Lastly, a system technical requirement could be generated automatically from the CASysE Tool-CORE.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.11
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• pp.50-57
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• 1997

In order to make unmanned machining systems with satisfactory performances, it is necessary to incorporate appropriate condition monitoring systems in the machining workstations to provide the required intelligence of the expert. This paper deals with condition monitoring for chatter, tool wear and breakage during turning operation. To develop economic sensing and identiffication methods for turning processes, sound pressure measurement and digital signal processing technique were proposed. We suppressed chatter by stability control methodology, which was studied through manipulation of spindle speeds regarding to chatter frequencies. It was shown that tool wear and fracture were identified and to be estimated by using the wear indices. The validity of the proposed system was confirmed through the large number of cutting tests.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.8
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• pp.48-53
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• 2010

5-axis CNC machining now is getting popular because it can deal with complex shapes such as impeller, turbine blade and propeller without additional equipment or process, proving a set of various tool orientations. CAM software related to 5-axis machining is being developed quickly so that users can take advantage of potential capacities of 5-axis machine tools. However, only a few researches can be found in the area of control strategy development for 5-axis machining. This paper proposes a 5-axis cross-coupling control system based on a novel tool orientation error model. The proposed tool orientation error model provides accurate information on the tool orientation error in real time, which in turn enables directly controlling the tool orientation accuracy. The proposed control system also employs a contour error model to calculate the contour error and reflect it in the control as well. The accuracy of the proposed tool orientation error model is verified and the performance of the 5-axis cross-coupling control system in terms of both contouring and tool orientation accuracy is evaluated through computer simulations compared with existing 5-axis control systems.

• Smart Structures and Systems
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• v.13 no.3
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• pp.407-418
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• 2014

The purpose of this paper is to present an Integrated Life Cycle Bridge Information Modeling that can be used throughout different phases of the bridge life cycle including: design, construction, and operation and maintenance phases. Bridge Information Modeling (BrIM) has become an effective tool in bridge engineering and construction. It has been used in obtaining accurate shop drawings, cost estimation, and visualization. In this paper, BrIM is used as an integrated tool for bridges life cycle information modeling. In the design phase, BrIM model can be used in obtaining optimum construction methods and performing structural advanced analysis. During construction phase, the model selects the appropriate locations for mobile cranes, monitors the status of precast components, and controls documents. Whereas, it acts as a tool for bridge management system in operation and maintenance phase. The paper provides a detailed description for each use of BrIM model in design, construction, and operation and maintenance phases of bridges. It is proven that BrIM is an effective tool for bridge management systems throughout their life phases.

• Journal of Electrical Engineering and Technology
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• v.1 no.4
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• pp.513-519
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• 2006

As a very important part in development of the protocol, verifications for developed protocol specification are complementary techniques that are used to increase the level of confidence in the system functions by their specifications. Using the informal method for specifying the protocol, some ambiguity may be contained therein. This indwelling ambiguity in control systems can cause the occurrence of accidents, especially in the case of safety-critical systems. To clear the vagueness contained in the designed protocol, we use the LTS (Labeled Transition System) model to design the protocol for railway signaling. And then, we verify the safety and the liveness properties formally through the model checking method. The modal ${\mu}$-calculus, which is an expressive method of temporal logic, has been applied to the model checking method. We verify the safety and liveness properties of Korean standard protocol for railway signaling systems. To perform automatic verification of the safety and liveness properties of the designed protocol, a communication verification tool is implemented. The developed tools are implemented by C++ language under Windows XP. It is expected to increase the safety and reliability of communication protocol for signaling systems by using the developed communication verification tool.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.569-574
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• 2002

As consumer's desire becomes various, agility of mold manufacturing is most important factor for competence of manufacturer. In common works to use commercial CAM system to generate tool path, some decision making process is required to produce optimal result of CAM systems, The paper proposes a methodology for computer-assisted tool selection procedures for various cutting type, such as rough, semi-rough and finish cuts. The system provides assist-tool-items for machining of design model part of injection meld die by analyzing sliced CAD model of die cavity and core. Also, the generating NC-code of the tool size is used to calculate machining time. The system is developed with commercial CAM using API. This module will be used for optimization of tool selection and planning process.

• Nuclear Engineering and Technology
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• v.38 no.3
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• pp.259-276
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• 2006

As the use of digital systems becomes more prevalent, adequate techniques for software specification and analysis have become increasingly important in nuclear power plant (NPP) safety-critical systems. Additionally, the importance of software verification and validation (V&V) based on adequate specification has received greater emphasis in view of improving software quality. For thorough V&V of safety-critical systems, V&V should be performed throughout the software lifecycle. However, systematic V&V is difficult as it involves many manual-oriented tasks. Tool support is needed in order to more conveniently perform software V&V. In response, we developed four kinds of computer aided software engineering (CASE) tools to support system specification for a formal-based analysis according to the software lifecycle. In this work, we achieved optimized integration of each tool. The toolset, NuSEE, is an integrated environment for software specification and V&V for PLC based safety-critical systems. In accordance with the software lifecycle, NuSEE consists of NuSISRT for the concept phase, NuSRS for the requirements phase, NuSDS for the design phase and NuSCM for configuration management. It is believed that after further development our integrated environment will be a unique and promising software specification and analysis toolset that will support the entire software lifecycle for the development of PLC based NPP safety-critical systems.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.3
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• pp.117-124
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• 2021

The development of IOT technology and artificial intelligence technology is promoting the smartization of manufacturing system. In this study, data extracted from acceleration sensor and current sensor were obtained through experiments in the cutting process of SKD11, which is widely used as a material for special mold steel, and the amount of tool wear and product surface roughness were measured. SVR (Support Vector Regression) is applied to predict the roughness of the product surface in real time using the obtained data. SVR, a machine learning technique, is widely used for linear and non-linear prediction using the concept of kernel. In particular, by applying GSVQR (Generalized Support Vector Quantile Regression), overestimation, underestimation, and neutral estimation of product surface roughness are performed and compared. Furthermore, surface roughness is predicted using the linear kernel and the RBF kernel. In terms of accuracy, the results of the RBF kernel are better than those of the linear kernel. Since it is difficult to predict the amount of tool wear in real time, the product surface roughness is predicted with acceleration and current data excluding the amount of tool wear. In terms of accuracy, the results of excluding the amount of tool wear were not significantly different from those including the amount of tool wear.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.435-435
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• 2000

Light Rail Transit (LRT) system is a complex and large system in which there are many subsystems, interfaces, functions and demanding performance requirements. Because many contractors participate in the development, it is necessary to apply methods of sharing common objectives and communicating effectively among all of the stakeholders. This paper shows not only the methodology and the results of computer-aided systems engineering including requirement management, functional analysis and architecting LRT system, but also propose a tool to help manage a project by linking WBS (Work Breakdown Structure), work organization and PBS (Product Breakdown Structure). The application of computer-aided tool RDD-100 provides the capability to model product design knowledge and decisions about important issues such as architecting the top-level system. The product design knowledge will be essential in integrating the following life-cycle phase activities over the life of the LRT system. Additionally, when a new generation train system is required, the reuse of the database can increase the system design productivity and effectiveness significantly.