• Proceedings of the Korea Society for Simulation Conference
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• 1998.10a
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• pp.204-208
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• 1998

The fundamental issues to evaluate machine tool's performance through simulation pertain to the physical models of the machine tool itself and of process while the practical problems are related to the development of the modular software structure. It allows the composition of arbitrary machine/process models along with the development of programs to evaluate each state of machining process. Surface roughness is one of the fundamental factors to evaluate machining process and performance of machine tool, but it is not easy to evaluate surface roughness due to its tribological complexity. This paper presents an algorithm to calculate surface roughness considering cutting geometry, cutting parameters, and contact dynamics of cutting between tool and workpiece as well as tool wear in turning process. The designed virtual machining system can be used to evaluate the surface integrity of a turned surface during the design and process planning phase for the design for manufacturability analysis of the concurrent engineering.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.6
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• pp.457-464
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• 2016

This study proposes a bi-directional buck-boost converter controller design method for ESS using the MATLAB SISO tool. The conventional two-loop controller design is based on a continuous S-domain model that designs each controller independently. The demerit of the conventional method is that optimal performance is not easily achieved and extensive trials and errors are required because two-loop systems interact with one another. Using the MATLAB SISO tool based on the design method proposed in this work overcomes the disadvantages of the conventional method. In the proposed method, the SISO tool can select the location of the poles and zeroes of the open loop system, thereby facilitating the effective design of a high-performance controller. The design sequence is detailed systematically, and the performance of the method is verified with a computer simulation and 10 kW experimental system.

• ETRI Journal
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• v.35 no.2
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• pp.259-269
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• 2013

Android has become the most popular platform for mobile devices. However, Android still has critical performance issues, such as "application not responding" errors and hiccups resulting from garbage collection. Many phone vendors have tried to resolve the problems by characterizing and improving the performance. However, there are few insightful performance analysis tools for the Android-based systems. This paper presents AndroScope, which is a performance analysis tool for both the Android platform (Dalvik virtual machine, core libraries, Android libraries, and even Linux kernels) and its applications. To the best of our knowledge, this is the first tool to collect and analyze performance data from all the software layers of the Android-based systems. AndroScope offers a trace mechanism to collect such deep and wide performance data as hardware performance counters, time, and memory usage. In addition, the tool includes TraceBridge, which is a middleware for the fast handling of mass logs. Moreover, AndroScope offers an integrated graphical user interface with the Android software development kit to display a great volume of the detailed performance data.

• Korean Institute of Interior Design Journal
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• no.37
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• pp.110-118
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• 2003

Computer simulation is one of the most useful techniques to predict daylighting performance and present visual image. In architectural and interior design practice, the Lightscape is commonly used often to produce persuasive images rather than physically accurate results. Therefore, this study is to validity the Lightscape as daylighting evaluation tool, in particularly performance and realistically visualization. For the purpose, an evaluation test model (12.0m$\times$7.2m$\times$3.0m) of side lighting window with lightshelf was selected. A 1:6 scale plywood physical model was made. Under clear sky condition, illuminance of 84 Interior point were measured. Lightscape was run on a 750 MHz Pentium PC running Windows 2000 under the same sky condition. And a photography image was compared to rendering image. The physical results of interior illuminance were within 8% between the scale model and Lightscape simulation. There were no differences between the photograph image and rendering image by Lightscape in the sight. Lightscape as visualization tool for daylighting performance was validated.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.5
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• pp.93-99
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• 2002

In general, manufacturing error is originated from bad material, machine tool defection and tool breakage. When the manufacturing process is stable, the most of error come from the tool wear. In common on-machine measurement teaching probe and touch sensor are widely used however in this paper the electric touch point type automatic tool compensation system is developed the performance of it is validated and effective operating is proposed.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.141-146
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• 2000

A flexible tool is developed for automatic finishing of curved surfaces without any complicated control technique on three-axes machining center. The tool is made of thermosetting polyurethane elastomer on the surface of which aluminum oxide abrasives are mounted. Performance and durability of the tool are examined by finishing ball-end milled surfaces of high-alloyed tool steel. It is demonstrated that the tool removes cusp successfully without changing overall surface shape in relatively short time.

• Journal of Korean Clinical Nursing Research
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• v.14 no.1
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• pp.71-84
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• 2008

Purpose: The purpose of this study was to develop a performance tool to evaluate operating room nurses. Method: In the first stage, 59 preliminary items were selected after two focus group meetings were carried out using as background a reference review. At this stage 59 items were developed. Next, the selected preliminary items were modified by an expert group of nurses with over 10 years experience, nurses holding doctoral degrees and professors in nursing. In the third and fourth stage, these items were analyzed by the expert group to determine validity and tested by hospital nurses with over 10 years experience to determine reliability Results: For the final tool, the 59 items, 47 items for the performance evaluation dimension and 12 items for the competence evaluation dimension were found to be valid and reliable. Cronbach's $\alpha$ was .9622, a promising alpha value for the total instrument. Conclusion: This tool is an efficient performance evaluation instrument providing meaningful feedback for operating room nurses.

• Steel and Composite Structures
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• v.21 no.3
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• pp.573-588
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• 2016

Carbon Fiber Reinforced Plastic (CFRP) and Titanium Alloy (Ti6Al4V) stack, extensively used in aerospace structural components are assembled by fasteners and the holes are made using drilling process. Drilling of stack in one shot is a complicated process due to dissimilarity in the material properties. It is vital to have optimal machining condition and tool geometry for better hole quality and tool life. In this study the tool wear and hole quality were analysed by experimental analysis using three modified twist drills and online tool condition monitoring using Acoustics Emission (AE) sensor. Helix angle and point angle influence tool performance and cutting force. It was found that a tool geometry (TG1) with high helix angle of $35^{\circ}$ with low point angle $130^{\circ}$ results in reduction in thrust force of 150-500 N range but the TG2 also perform almost similar to TG1, but when compared with the AErms voltage generated during drilling it was found that progressive rise in voltage in TG1 is less with respect to TG2 which can be attributed to tool life. In process wear monitoring was done using crest factor as monitoring index. AErms voltage were measured and correlated with the performance of the drills.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.6
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• pp.1397-1404
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• 2017

When a digital forensic investigation is conducted on a damaged storage medium, recovery is performed using a recovery tool. But the result of each recovery tool is different depending on the tools. Therefore, it is necessary to identify and use the performance and limitations of the tool for accurate investigation. In this paper, we propose a scenario considering the disk recognition type such as MBR, GPT and the structural characteristics of FAT32 and NTFS filesystem to verify the performance of the partition recovery tool. And then We validate the existing tools with the data set built on the scenarios.

• Journal of Information Technology Services
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• v.6 no.2
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• pp.161-175
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• 2007

Face recognition technology has lately attracted considerable attention because of its non-intrusiveness, usability and applicability. Related companies insist that their commercial products show the recognition rates more than 95% according to their self-testing. But, the rates cannot be admitted as official recognition rates. So, performance evaluation methods and tools are necessary to objectively measure the accuracy and performance of face recognition systems. In this paper, I propose a reference model for biometrics recognition evaluation tools, and implement an evaluation tool for the face recognition system based on the proposed reference model.