• 한국공작기계학회논문집
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• 제17권4호
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• pp.133-139
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• 2008

With the increasing demand for higher production quality and growing competition in the global market, coordinate measuring machine(CMM) has been widely used in industry to improve the efficiency and effectiveness of measurement. In this paper the performance evaluation of coordinate measuring machine is proposed using design of experiments. A factorial design is applied to carry out the performance test proposed by ISO 10360 with a length bar and to investigate CMM measurement errors associated to orientation and length in the work volume. The determination of the significance of effects in an experiment is made through the analysis of variance(ANOVA). The results show that the proposed method is suitable to analyze the factors which affect the CMM measurement performance.

• 한국정밀공학회지
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• 제26권4호
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• pp.91-99
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• 2009

Because of both precise measurement and efficient quality control, coordinate measuring machines(CMMs) have been widely used in the industry. The purpose of this paper is to present a method to estimate the CMM measurement uncertainty using design of experiments. A factorial design is applied to carry out the performance test proposed by ISO 10360 and to investigate CMM measurement errors associated to orientation and length of the length bar. In order to assess the measurement uncertainty for the performance test, an analysis of the uncertainty components that make up the uncertainty budget has been carried out. The procedure for evaluating the uncertainty of it follows GUM ("Guide to the expression of uncertainty in measurement"). The results show that the proposed method is suitable to investigate CMM performance and determine the contribution of machine variables to measurement uncertainty.

• Journal of Biosystems Engineering
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• 제31권4호
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• pp.349-354
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• 2006

This study was performed to evaluate the performances for a concurrent flow rice dryer of pilot scale with devices for circulating rice. The pilot scale dryer with the capacity of 700 kg was developed to obtain design informations for the development of actual scale dryer of holding capacity of 10 tons. Three drying tests were conducted at two temperature levels of $100^{\circ}C\;and\;120^{\circ}C$, and two air flow rates levels of $28.5cmm/m^2\;and\;57.1cmm/m^2$. Drying conditions for Test-1, Test-2 and Test-3 were $100^{\circ}C\;-28.5cmm/m^2,\;120^{\circ}C-28.5cmm/m^2\;and\;120^{\circ}-57.1cmm/m^2}$ respectively. Drying rates were 0.73%(w.b./h) for Test-1, 0.90%(w.b./h) for Test-2 and 1.46%(w.b./h) for Test-3. The crack ratios of brown rice after drying ranged from 2.4% to 8.4%, and increased with the increase of drying rate and airflow rate. The energy consumptions were from 6,225 kJ/kg to 6,993 kJ/kg which was higher than that of conventional cross-flow rice circulating type dryer used in Korea. This results were due to the lower ambient air temperatures of $4.5^{\circ}C\;to\;13.4^{\circ}C$ during drying tests.

• Journal of Biosystems Engineering
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• 제34권5호
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• pp.358-362
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• 2009

This study was conducted to evaluate the performance of a 12 tons capacity circulating concurrent flow rice dryer. An actual scale dryer with the capacity of 12 tons was developed to obtain a faster drying rate of 0.8~1.2%(w.b.)/h, while maintaining a lower drying energy consumption of 5,000 kJ/kg-water and achieving a drying quality that was comparable to a conventional cross-flow rice dryer. The Test-1 was conducted at $110^{\circ}C\;-\;20\;cmm/m^2$ and the Test-2 was conducted at $120-110-100-90^{\circ}C\;-\;20\;cmm/m^2$ under the same conditions as Test-1. In Test-1, the drying rate, drying energy consumption and crack ratio were 0.98 %(w.b.)/h, 4,573 kJ/kg-water and 3.2%, respectively. In Test-2, the drying rate, drying energy consumption and crack ratio were 0.74 %(w.b.)/h, 4,790 kJ/kg-water and 4.0%, respectively. The results of these tests demonstrated that this concurrent-flow dryer reached the desired drying rate, drying energy consumption and crack ratio.

• 한국태양에너지학회 논문집
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• 제25권3호
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• pp.37-45
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• 2005

Higher requirement of advanced building design code and the development of construction technique have resulted in more thermal and air tight buildings. This has caused the sick building syndrome in a indoor air quality has been relatively getting worse. A new concept with a solar fresh air heating and electrostatic precipitator or called as STCC(Solar Transpired Collector and Cyclone) has been proposed to solve this IAQ issue. This paper describes the assessment study of STCC system under different outdoor airflow rates. The experiment was carried out under real condition with 30CMM STCC system test facility. Incense smoke was used to study the particle concentration decay trends under outdoor airflow rates 0CMM, 10CMM, 20CMM, 30CMM, with applied voltages of 5kV and 15kV for collecting and discharging electrodes of an Electrostatic Precipitator. Result shows that the particle decay increases by increasing the outdoor airflow rates. The collection efficiency, dust cleaning effectiveness(P) and application area calculation result comparisons have also been studied. This factors could be used to estimate how a dust of indoor air quality(IAQ) and removed for a building space with a STCC system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.268-271
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• 2003

The Volumetric Interferometer using two spherical wavefronts emitted from the ends of two single mode fibers has been suggested to measure 3-dimensional absolute coordinates. In this paper, we try to improve the performance of the volumetric interferometer using multi-CCDs. We get coordinates matching matrixes between CCDs and can obtain more information in the space with multi-CCDs. Also we find out the best arrangement of multi-CCDs by computer simulations. In the simulation we can know that it will be better to increase the distance between CCDs to improve performance. For the performance test, we do a repeatability test, a comparison test with 2-D stage and the self-calibration using artifact.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.219-223
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• 2006

This paper presents a gantry type 3-axes positioning system, which is useful to test control algorithms for coordinate measuring machines and industrial cranes. The dynamic characteristics of the system have been investigated through a series of finite element analysis and experiments. In order to minimize the residual vibration during movement, this paper implements input shaping algorithms for the system with the information from the dynamic analysis. The results show that the dynamic performance of the system can be significantly improved by the dynamic analysis and implementation of input shaping

• 산업공학
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• 제16권3호
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• pp.362-374
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• 2003

The major objective of this paper is to empirically examine the effect of process maturity on the performance of industrial R&D projects. Process maturity, a fundamental concept of the Capability Maturity Model developed by Software Engineering Institute, represents the essential of Total Quality Management (TQM). Based on literature, our research model constructs process maturity in terms of structured process, goal setting and controlling, metrics, and process learning; and links it to the R&D performance that consists of technical, commercial and managerial successes. The model also includes firm size as a moderator of different effects that process maturity may have across firms. Measures for process maturity are based on the best practices identified in literature. Data are obtained from 77 successful R&D projects carried out by Korean manufacturing firms. Multiple regression and t-test are used to test proposed hypotheses. Findings are as follows. (1) In the R&D process, process maturity partially contributes to the performance of R&D projects. More specifically, goal setting and controlling-related practices drive both technical and commercial successes, while process learning-related practices drive commercial success. In contrast, traditionally emphasized elements such as structured process or metrics are found not to be significant. (2) The degree of process maturity is significantly higher in large firms. (3) Process maturity impacts on commercial success in the case of large firms, whereas it does on technical success in the case of small firms. The results imply that the TQM principles are partially associated with R&D performance, and the nature of benefit from high maturity could vary according to firm size.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.532-537
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• 2000

The purpose of this study is to determine the performance of a commercial air cleaner in removing tobacco smoke indoors. Following injection of tobacco smoke in a room, decay rates for particle concentrations were obtained far mass concentration at each point. The size distribution of the tobacco smoke particles was approximately $1.266{\mu}m$ in mass median diameter with a geometric standard deviation of 1.313. The air cleaner consisted of an electrostatic filtration unit and a fan operated at a flow rate of 5.98 CMM. The collection efficiency for $>1\;{\mu}m$ was more than 99%. Without air cleaner operation, tobacco smoke concentration ratio in room decreased to 30% of initial values within 30 minutes and with air cleaner operation, decreased to 90% of initial values in the test chamber, volume $51.27\;m^3$. Without air cleaner operation, tobacco smoke concentration ratio in room decreased to 10% of initial values within 30 minutes and with air cleaner operation, decreased to 30-70% of initial values in the test chamber, volume $149.2\;m^3$.