• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.327-332
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• 2000

This study was carried out to investigate the water requirement of green peppers which are cultivated in a greenhouse under the different soil water conditions. The meteorological conditions during the experiment period was not predominantly different from the conditions in a normal year. The highest leaf area per plant, plant height, and yield were 6,143$\textrm{cm}^2$/plant, 107cm, and 751g/plant, respectively. And daily variation of water requirements of green peppers ranged from 30 to 1,250g/d/plant which was fluctuated with significant difference. Total water requirements per plant which cultivated under the soil water conditions with different saturation ratios were 23,619g for P100, 43,044 for P80, and 2915g for P60, respectively. There were close correlation between plant height and water requirements. Low correlations were found between greenhouse ambient temperature and water requirement, while significant linear regression was shown between both of humidity and solar radiation and water requirement.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.5
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• pp.529-535
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• 2009

One of the most important things in shipbuilding is to select light and high tensile strength materials. Therefore, the use of Al alloy in shipbuilding become an increase. In cutting the aluminum plate, the quality of the cut surface is strongly influenced by the cutting conditions such as cutting speed, kerf width, plate thickness, cutting materials, and applied gas pressure. The cutting experiment of Al alloy plate(5083) were carried out using LASER cutting machine. The upper and lower of kerf width, the surface roughness(Ra, Rmax) of cut surface were measured under various cutting conditions. The morphologies of cutting surface were also monitored at various cutting conditions. The optimum cutting conditions of Al alloy among tested were indicated.

• Design & Manufacturing
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• v.18 no.2
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• pp.41-50
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• 2024

In this study, experimental design methods were used to derive optimal process conditions for improving the thickness uniformity of a 0.40 mm, 3.5 inch light guide panel. Process mapping and expert group analysis were used to identify factors that influence the thickness of injection molded products. The key factors identified were mold temperature, mold temperature, injection speed, packing pressure, packing time, clamp force, and flash time. Considering the resin manufacturer's recommended process conditions and the process conditions for similar light guide plates, a three-level range was selected for the identified influencing factors. L27 orthogonal array process conditions were generated using the Taguchi method. Injection molding was performed using these L27 orthogonal array to mold the 3.5 inch light guide plates. Thickness measurements were then taken, and the results were analyzed using the signal-to-noise ratio to maximize the CpK value, leading to the determination of the optimal process conditions. The thickness uniformity of the product was analyzed by applying the derived optimum process conditions. The results showed a 97.5% improvement in the Cpk value of 3.22 compared to the process conditions used for similar light guide plates.

• Design & Manufacturing
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• v.18 no.2
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• pp.64-73
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• 2024

The purpose of this paper is to introduce a fusion method that combines the design of experiments (DOE) and machine learning to optimize the bias of plastic products. The study focuses on the plastic motor housing used in automobiles, which is manufactured through plastic injection molding. Achieving optimal molding for the motor housing involves the optimization of various molding conditions, including injection pressure, injection time, holding pressure, mold temperature, and cooling time. Failure to optimize these conditions can lead to increased product deformation. To minimize the deformation of the motor housing, the widely used Taguchi method, which is one of the design of experiment techniques, was employed to identify the injection molding conditions that affect deformation. Machine learning was then applied to various models based on the identified molding conditions. Among the models, the Random Forest model emerged as the most effective in predicting deformation amounts. The validity of the Random Forest model was also confirmed through verification. The verification results demonstrated the excellent prediction accuracy of the trained Random Forest model. By utilizing the validated model, molding conditions that minimize deformation were determined. Implementation of these optimal molding conditions led to a reduction of approximately 5.3% in deformation compared to the conditions before optimization. It is noteworthy that all injection molding outcomes presented in this paper were obtained through robust injection molding simulations, ensuring both research objectivity and speed.

• Science of Emotion and Sensibility
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• v.13 no.1
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• pp.69-78
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• 2010

LED technology offers versatile lighting control while having a very low environmental impact. Consequently, increasing attention is being paid to the emotional impact of LED lighting. This study investigated whether the chromacity of LED lighting influences people's time perception. To this end, two empirical studies were conducted: First, in experiment I(N=28), the subjects compared their perception of the time duration, which was varied from 3s to 20s, for 6 chromatically nuanced lighting conditions, respectively, with that under a daylight condition. The results showed that, in warm-color nuanced lighting conditions, the subjects perceived time to pass more slowly than in the daylight condition. On the contrary, in cool-color nuanced lighting conditions, the subjects perceived time to pass more rapidly than in the daylight condition. Then, in experiment II(N=39), the subjects were asked to count for 90 seconds while simultaneously performing some cognitive tasks. Confirming the results found in experiment I, the subjects perceived time to pass more rapidly in cool-color nuanced lighting conditions than in warm-color nuanced lighting conditions, although the difference was not statistically significant(p>0.05). In addition, the subjects tended to perceive the time to be shorter when the nuanced color of the light was closer to their preferred color.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.4
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• pp.372-377
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• 2015

In this paper, the consideration factors that affect the actual driving of a rover wheel was examined based on the wheel-terrain model. For the evaluation of driving performance in a real environment, the test bed of the rover wheel consists of the driving part of the wheel and sensing part of the various parameters was designed and assembled. Using the test bed, the preliminary driving experiment concerning the slip ratio, sinkage, and friction force according to the rotational velocity and the shape of the wheel were carried out and evaluated. The wheel test bed and the experiment results are expected to contribute to finding the optimal result in the designing of the wheel shape and the planning of the driving conditions through further study.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.7
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• pp.58-64
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• 2009

In this paper, an inspection mechanism based on laser scattering has been developed for the surface evaluation of infrared cut-off filters, and optimum conditions of laser scattering are determined using the design of experiment. First of all, attributes and influence factors of laser scattering are investigated and then a laser scattering inspection mechanism is newly designed based on analyses of laser scattering parameters. Also, Taguchi method, one of experimental designs, is used for the optimum condition selection of laser scattering parameters and the optimum condition is determined in order to maximize the detection capability of surface defects. Experiments show that the proposed method is useful in a consistent and effective defect detection and can be applied to surface evaluation processes in manufacturing.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1511-1516
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• 2007

Because Seaming process of MPJ (Mechanical Press Joining) has various design factors such as thickness, bending radius, seaming width, caulking press width and the dynamic factor such as multistage plastic working, elastic recovery, residual stress, the optimum conditions can't be easily determined. Using a design of experiment based on the FEM, which has several advantages such as less computing, high accuracy performance and usefulness, this study was performed investigating the interaction effect between the various design factor as well as the main effect of the each design factor during drum MPJ and proposed optimum condition using center composition method among response surface derived from regression equation of simulation-based DOE.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.4
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• pp.15-21
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• 2007

The effect of manufacturing parameters on friction characteristics of motorcycle break system was studied using a disk-on-pad type friction tester. Such parameters conditions have an effect on the frictional factor such as number of ventilated disk hole, applied load, sliding speed, and sliding distance. However, it is difficult to know the mutual relation of these factors. In this study, the friction characteristics using design of experiment containing 4 elements were investigated for an optimal condition for the best motorcycle break system employing regression analysis method. From this study, the result was shown that the applied load in frictional factors was the most important, next to sliding speed, number of ventilated disk hole.

• Proceedings of the KSPS conference
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• 2007.05a
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• pp.173-175
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• 2007

The lexical decision task (LDT) commonly postulates the activation of semantic level. However, there are few studies for the feedback effect from semantic level. The purpose of the present study is to investigate whether the feedback effect from semantic level is facilitatory or inhibitory in Korean LDT. In Experiment 1, we manipulated the number of phonological syllable neighbors (PSN) and the number of semantic neighbors (SEN) orthogonally while orthographic syllable neighbor (OSN) is dense. In the results, the significant facilitatory effect was shown in words with many SEN. In Experiment 2, we examined same conditions as Experiment 1 but OSN was sparse. Although the similar lexical decision latency pattern was shown, there was no statistical significance. These results can be explained by the feedback activation from semantic level. If a target has many SENs and many PSNs, it receives more feedback activation from semantic level than a target with few SENs and PSNs.