• Journal of the Korean institute of surface engineering
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• v.46 no.6
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• pp.264-270
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• 2013

Effects of preoxidation on high temperature wear of piercing plug tool steel sliding against SA210C steel used for production of seamless tube have been studied using a pin-on-disc CETR tribometer, under applied normal load of 20 N at $900^{\circ}C$ in air. It was found in the preoxidized pin specimens of piercing plug tool steel that the coefficient of friction decreased to about 0.4 at an initial stage followed by showing nearly constant value of about 0.4 during high temperature wear testing. On the other hand, it was also found in the pin specimens without preoxidation that the coefficient of friction increased and fluctuated, ranging from about 0.3 to 0.6 during the tests until the running period of about 800 sec. The compact and continuous Fe-oxide layer was formed on the contact surface of the preoxidized pin specimens after high temperature wear testing followed by penetrating along the grain boundaries of coarse ferrite in the decarburized region beneath the oxide layer due to the lower hardness of the region.

• Journal of Korean Academy of Nursing
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• v.44 no.3
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• pp.339-349
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• 2014

Purpose: This study was done to develop a measurement for stress experienced by patients with schizophrenia during hospitalization. Methods: The preliminary tool was developed through in-depth interviews and a validity verification test of content. For data collection, 15 inpatients with schizophrenia were selected as participants for in-depth interviews and 195 patients admitted to one of eight psychiatric hospitals in four provinces were recruited as participants to test reliability and validity of the preliminary tool. Results: The questionnaire was developed as a four-point Likert-type scale in a self-report form with 28 items. Factor analysis showed 28 items in six factors. Factors were named 'Unjust human rights infringement', 'Futureless life', 'Alienation from other family members', 'Infringement of basic needs', 'Infringement of personal preference' and 'Inconvenience of shared living'. The six factors explained 63.5% of the total variance. Cronbach's alpha for the total items was .93 and for the factors ranged from .65 to .87. Conclusion: A tool to measure stress in patients hospitalized with schizophrenic was developed based on identified hospitalization stress experiences. Study results indicate that this tool can be used to evaluate hospitalization stress in these patients and will contribute to establishing nursing interventions for relief of hospitalization stress.

• Journal of Digital Convergence
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• v.10 no.9
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• pp.383-390
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• 2012

In this paper, we suggest an information retrieval visualization tool using the knowledge representation method. Information retrieval visualization tool suggested in this paper is designed to automatically extract retrieval intention using user's search history data and visualize extracted retrieval intention in the knowledge representation method structure. A psychological knowledge representation methodology was adopted for schema for retrieval intention representation and its effectiveness has been proved through the behavioral experiments. Result of experiment revealed that information retrieval visualization tool has been improved approximately 39% in user satisfaction compared to existing retrieval method, suggesting a measure to solve re-retrieval problem in the process of information retrieval.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.10
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• pp.1541-1548
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• 2004

A nano-stage simulation tool is developed for an advanced E-beam lithography system. Even if piezo-actuators are believed to be compatible fer the E-beam lithograpy system it is difficult to predict their characteristics due to their nonlinearities such as hysteresis and creep. In this paper, the nonlinear properties are modeled for a piezo-actuator by considering the voltage range and speed variations. The hysteresis is described as the first order differential equation with 24 sets of parameters and the creep is modeled as a time-dependent logarithmic function with 2 sets of a parameter. A two-axis nano stage with piezo-actuators are investigated for realizing nano scale motions. The characteristics of flexure guide mechanisms are analyzed based on the finite element method using the ANSYS software. The simulation tool for the nano stage is constructed by using the RecurDyn software. The dynamic response of the nano stage is obtained in simulations and compared with the experimental data.

• Journal of Korean Academy of Nursing
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• v.27 no.4
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• pp.753-764
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• 1997

This study was conducted to develop a sexual satisfaction tool for married women in Korea. The data was collected from July 19 to Aug 18, 1997 by means of questionnaires developed by researchers. The subject were 417 married women living in Seoul and Pusan. The process of this study was as follows : 1) The concept of sexual satisfaction was defined. 2) A conceptual framework was identified based on the extensive review of relevant literature and interviews with married women. 3) The preliminary question items containing the attributes and elements of the concept of sexual satisfaction were listed. 4) The preliminary items were revised after a pilot study. 5) The Index of Content Validity(CVI) was calculated from the content specialists' rating. 6) The reliability and validity of the sexual satisfaction measurement tool were tested. As a result of the item and factor analysis, 17 out of 30 items were found to be valid, consequently could be used to measure sexual satisfaction for married women. These final 17 items were divided into two factors. These factors were labeled as "situation factor" (10 items) and "response factor"(7 items) according to the attributes of the clustered items. The reliability of the final 17 items was .9118. Further research is needed to confirm the reliability and validity of the tool by applying it to a group of healthy married women and to a group of married women having health-related problem.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.1 no.1
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• pp.38-47
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• 2002

Machining quality has been improved with the development of cutting tools. However, it is difficult to obtain a high degree of quality in machining a deep pocket with a long end mill, since machining accuracy is mainly dependent on the stiffness of the cutting tool and tool holder. To improve machining quality in machining a deep pocket using an end mill, the performance by cutting condition compare with others. Owing to this problem, it is necessary to select suitable tool and holder in the deep pocket machining. In this study, the hydraulic holder for the high speed machining is introduced and the performance of that is compared with others according to cutting conditions. The cutting parameters involved were; slenderness ratio in the range of 3 to 6 (L/D), radial depth of cut from 0.01 to 0.05 mm. Cutting force and surface roughness, precision of form were observed during the experiment to investigate cutting state.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.530-537
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• 2004

Development of a versatile nanomanipulation tool is an overarching theme in nanotechnology. Such a tool will likely revolutionize the field given that it will enable fabrication and operation of a wealth of interesting nanodevices. This study seeks funding to create a novel nanomanipulation system with the ultimate goal of using this system for nanomanufacturing at the molecular level. The proposed design differs from existing approaches. It is based on a nanoscale ion trap integrated to a scanning prove microscope (SPM) tip. In this design, molecules to be assembled will be ionized and collected in the nanoscale ion trap all in an ultra high vacuum (UHV) environment. Once filled with the molecular ions, the nanoscale ion trap-SPM tip will be moved on a substrate surface using scanning probe microscopy techniques. The molecular ions will be placed at their precise locations on the surface. By virtue of the SPM, the devices that are being nanomanufactured will be imaged in real time as the molecular assembly process is carried out. In the later stages, automation of arrays of these nanomanipulators will be developed.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.5
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• pp.507-512
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• 2013

This paper proposes a new model to compensate for errors of a five-axis machine tool. A matrix with error components, that is, an error matrix, is separated from the error synthesis model of a five-axis machine tool. Based on the kinematics and inversion of the error matrix which can be obtained not by using a numerical method, an error compensation model is established and used to calculate compensation values of joint variables. The proposed compensation model does not need numerical methods to find the compensation values from the error compensation model, which includes nonlinear equations. An experiment using a double ball-bar is implemented to verify the proposed model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1887-1892
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• 2005

In the future, a machine-tool will be more improved in the form of a knowledge evolution based device. In order to develop the knowledge evolution based machine-tool, this paper proposes the structure of standard M2M(Machine To Machine) and the scheme of agent communication in environment. The communication agent such as dialogue agent has a role of interfacing with another machine for cooperation. To design of the communication agent module in M2M environment, FIPA(Foundation of Intelligent Physical Agent) and ping agent based on JADE(Java Agent Development Framework) or FIPA-OS(Open Source) are analyzed in this study. Through this, it is expected that the agent communication can be more efficiently designed and the knowledge evolution based machine-tool can be hereafter more easily implemented.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.2
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• pp.71-76
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• 2003

A virtual machine tool (VMT) is presented in this two-part paper. In Part 1, the analytical foundation for a virtual machining system is developed, which is envisioned as the foundation for a comprehensive simulation environment capable of predicting the outcome of cutting processes. The VHT system undergoes "pseudo-real machining", before actual cutting with a CNC machine tool takes place, to provide the proper cutting conditions for process planners and to compensate or control the machining process in terms of the productivity and attributes of the products. The attributes can be characterized by the machined surface error, dimensional accuracy, roughness, integrity, and so forth. The main components of the VMT are the cutting process, application, thermal behavior, and feed drive modules. In Part 1, the cutting process module is presented. When verified experimentally, the proposed models gave significantly better prediction results than any other methods. In Part 2 of this paper, the thermal behavior and feed drive modules are developed, and the models are integrated into a comprehensive software environment.vironment.