• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.9
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• pp.22-32
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• 1997

This paper proposes an imprecise compuitation model for DCT considering QOS of images and a two dimensional DCT architecture for imprecise computations. In case that many processes are scheduling in a hard real time system, the system resources are shared among them. Thus all processes can not be allocated enough system resources (such as processing power and communication bandwidth). The imprecise computtion model can be used to provide scheduling flexibility and various QOS(quality of service)levels, to enhance fault tolerance, and to ensure service continuity in rela time systems. The DCT(discrete cosine transform) is known as one of popular image data compression techniques and adopted in JPEG and MPEG algorithms since the DCT can remove the spatial redundancy of 2-D image data efficiently. Even though many commercial data compression VLSI chips include the DCST hardware, the DCT computation is still a very time-consuming process and a lot of hardware resources are required for the DCT implementation. In this paper the DCT procedure is re-analyzed to fit to imprecise computation model. The test image is simulated on teh base of this model, and the computation time and the quality of restored image are studied. The row-column algorithm is used ot fit the proposed imprecise computation DCT which supports pipeline operatiions by pixel unit, various QOS levels and low speed stroage devices. The architecture has reduced I/O bandwidth which could make its implementation feasible in VLSI. The architecture is proved using a VHDL simulator in architecture level.

• Journal of Radiation Protection and Research
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• v.20 no.1
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• pp.37-44
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• 1995

Since provisions on the technical criteria for personnel dosimetry was amended three years ago, several improvements in the technique of monitoring personnel doses by TLD have taken place, but for the photograpfic film as a personnel monitor, additional investigations should be carried out for its accuracy of dose estimates because of its wide use in the radiation involved industries. So, this paper describes the methods to develope dose evaluation algorithm for photographic film using ISO reference radiations by i) empirical formula, ii) degree-of-fit method, and iii) matrix approximation. These methods show a good agreement between irradiated and calculated dose within tolerance level represented in ANSI N13. 11, and can be used for the dose evaluation of X, ${\gamma}$ and/or radiation fields.

• Journal of Mechanical Science and Technology
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• v.15 no.3
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• pp.309-319
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• 2001

This paper demonstrates the development of optical temperature sensor based on the etched silica-based planar waveguide Bragg grating. Topics include design and fabrication of the etched planar waveguide Bragg grating optical temperature sensor. The typical bandwidth and reflectivity of the surface etched grating has been ∼0.2nm and ∼9%, respectively, at a wavelength of ∼1552nm. The temperature-induced wavelength change is found to be slightly non-linear over ∼200$^{\circ}C$ temperature range. Typically, the temperature-induced fractional Bragg wavelength shift measured in this experiment is 0.0132nm/$^{\circ}C$ with linear curve fit. Theoretical models with nonlinear temperature effect for the grating response based on waveguide and plate deformation theories agree with experiments to within acceptable tolerance.

• Journal of Korean Institute of Industrial Engineers
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• v.17 no.2
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• pp.75-86
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• 1991

This paper presents a methodology to enable the tolerances on mating parts of an assembly to be specified and be compatible to the precision of an assembly robot so as to achieve maximum system performance. The measure of performance is defined as the Probability of Successful Assembly (PSA). A typical loose fastener assembly, usually called peg-in-a-hole is investigated. The Geometric Tolerancing System is adopted to represent position tolerances of mating parts. Two models are presented by considering modifiers on a position tolerance, Regardless of Feature Size (RFS) and Maximum Material Condition (MMC). Using these models, it is analyzed how the Standard Limits and Fits recommended by ANSI influence the performance of an assembly robot. For this analysis, the Standard Limits and Fits are transformed to the representation scheme of the Geometric Tolerancing System. Due to low PSAs when the Standard Limits and Fits are taken into account, the effect of chamfers around a hole is also analyzed.

• Journal of Engineering Education Research
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• v.23 no.5
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• pp.61-67
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• 2020

In the associate degree curriculum of the department of mechanical engineering, the results of the study are presented on the structure and content of a subject based on the case-based learning method. As an case, equipment called a laminator that is actually used in the manufacturing site was selected. Class deals with specific engineering issues at each stage of laminator manufacturing (design-machining-assembly-measurement-maintenance) in connection with general engineering topics in prerequisites in the curriculum. Topics include tolerance fit, length measurement, assembly practice, measurement design and statistics of machine maintenance, etc. Courses that apply the case-based learning method may be included in the curriculum as complementary roles to those that apply other student-centered learning method.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1371-1373
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• 2005

Nowadays, Intelligent Electronic Devices(IED) are widely used in power system. In order to improve the selectivity, sensitivity, and reliability of the power system composed by IEDs, A new fault tolerant IED system based on agent technique is presented in this paper. in the presented system, different with existing IED systems, the redundancies are drawn out from IED devices, and compose a standby backup system. And those redundancies are not specified to a particular type of IEDs. By using the agent technique, redundancies can download agents to modify their functions to fit different types of IEDs. As a conclusion, the reliability of the presented system is estimated in this paper.

• Mass Spectrometry Letters
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• v.14 no.4
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• pp.173-177
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• 2023

Kendrick plots offer an alternative visualization of mass spectral data which reveals ion series and patterning by turning a mass spectrum into a map, plotting the fractional mass (wrongly called mass defect) as a function of mass-to-charge ratios and ion abundances. Although routinely used for polymer mass spectrometry, two unreported applications of these Kendrick plots are proposed using the program "kendo2": the graphical recalibration of a mass spectrum via the simulation of a theoretical fractional mass and a multi-segment fit; and the rapid evaluation of scan-to-scan variation of accurate mass measurements used as tolerances for the blank subtraction of UPLC-MS data files. Both applications are compatible with any type of high-resolution MS data including LC/GC-MS(/MS).

• The Korean Journal of Applied Statistics
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• v.20 no.1
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• pp.1-9
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• 2007

This investigation on the change of the daily maxima temperature in Seoul, Daegu, Chunchen, Youngchen was triggered by news items such as the earth is getting warmer and a recent news item that said that Korea is getting warmer due to this climatic change. A statistical analysis on the daily maxima for June over this period in Seoul revealed a positive trend of 1.1190 centigrade over the 45 years, a change of 0.0249 degrees annually. Due to the large variation on these maximum temperatures, one can raise the question on the significance of this increase. To check the goodness of fit of the proposed extreme value model, we shown a Q-Q plot of the observed quantiles against the simulated quantiles and a probability plot. And we calculated statistics each month and a tolerance limit. This is tested through simulating a large number of similar datasets from an Extreme Value distribution which described the observed data very well. Only 0.02% of the simulated datasets showed an increase of this degrees or larger, meaning that the probability is very low for such an event to occur.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1749-1752
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• 2005

High speed machining has become the main issue of metal cutting. Due to increase of the rotational speed of the spindle, problems, such as the run-out errors, reduced stiffness, must be overcome to improve the machining accuracy. In order to solve the problems, it is important to determine the appropriate clamping unit and tooling system. This paper presents an investigation into an evaluation of contact interval which is the interface between spindle taper hole and tool holder shank of the spindle. Finite element analysis is performed by using a commercial code ANSYS according to variation of clamping forces and rotational speeds. This paper proposed fit tolerance in order to evaluate the effects of clamping force and rotational speed on the contact interval in the spindle interface. From the finite element results, it has been shown that the rotational speed rather than clamping force mostly influence on the variation of the contact interval.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.3 s.180
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• pp.147-155
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• 2006

High speed machining has become the main issue of metal rutting. Due to increase of the rotational speed of the spindle, problems, such as the run-out errors, reduced stiffness, must be overcome to improve the machining accuracy. In order to solve the problems, it is important to determine the appropriate clamping unit and tooling system. This paper presents an investigation into an evolution of contact interval which is the interface between spindle taper hole and tool holder shank of the spindle. Finite element analysis is performed by using a commercial code ANSYS according to variation of clamping forces and rotational speeds. This paper proposed fit tolerance in order to evaluate the effects of clamping force and rotational speed on the contact interval in the spindle interface. From the finite element results, it has been shown that the rotational speed rather than clamping force mostly influence on the variation of the contact interval.