• Proceedings of the KOSOMBE Conference
• /
• v.1996 no.11
• /
• pp.95-98
• /
• 1996

In this paper, The vehicle's path construction method for motorized wheelchair's autonomous navigation in a building through analysis of a corridor image using vision system has been proposed and We detected lines of vertical axis through camera distortion parameter, which was measured by camera calibration in a corridor image. Then we got the feature points in the lines. We analyzed the distance of feature points and what is feature points. we reconstructed corridor image to vehicle's path.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.11 no.1
• /
• pp.27-38
• /
• 2009

The multi-level profile system is designed to measure the vertical profile of $H_2O$ and $CO_2$ concentrations in the surface layer to estimate the storage effects within the plant canopy. It is suitable for long-term experiments and can be used also in advection studies for estimating the spatial variability and vertical gradients in concentration. It enables the user to calculate vertical fluxes of water vapor, $CO_2$ and other trace gases using the surface layer similarity theory and to infer their sources or sinks. The profile system described in this report includes the following components: sampling system, calibration and flow control system, closed path infrared gas analyzer(IRGA), vacuum pump and a datalogger. The sampling system draws air from 8 inlets into the IRGA in a sequence, so that for 80 seconds air from all levels is measured. The calibration system, controlled by the datalogger, compensates for any deviations in the calibration of the IRGA by using gas sources with known concentrations. The datalogger switches the corresponding valves, measures the linearized voltages from the IRGA, calculates the concentrations for each monitoring level, performs statistical analysis and stores the final data. All critical components are mounted in an environmental enclosure and can operate with little maintenance over long periods of time. This report, as a practical manual, is designed to provide helpful information for those who are interested in using profile system to measure evapotranspiration and net ecosystem exchanges in complex terrain.

• Journal of Drive and Control
• /
• v.20 no.4
• /
• pp.115-122
• /
• 2023

This study utilized a discrete element method (DEM) simulation, as one of the virtual field trials, to predict the impact of tillage depth on the rotary blade shaft during rotavator tilling. The virtual field for the simulation was generated according to soil properties observed in an actual field. Following the generation of particles for the virtual field, a sequence of calibration steps followed to align the mechanical properties more closely with those of real soil. Calibration was conducted with a focus on bulk density and shear torque, resulting in calibration errors of just 0.02% for bulk density and 0.52% for shear torque. The prediction of the load on a rotary tiller's blade shaft involved a three-pronged approach, considering shaft torque, draft force, and vertical force. In terms of shaft torque, the values exhibited significant increases of 42.34% and 36.91% for every 5-centimeter increment in tillage depth. Similarly, the vertical force saw substantial growth by 40.41% and 36.08% for every 5-centimeter increment. In contrast, the variation in draft force based on tillage depth was comparatively lower at 18.49% and 0.96%, indicating that the effect of tillage depth on draft force was less pronounced than its impact on shaft torque and vertical force. From a perspective of agricultural machinery research, this study provides valuable insights into the DEM soil modeling process, accounting for changes in soil properties with varying tillage depths. These findings are expected to be instrumental in future agricultural machinery design studies.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.9
• /
• pp.34-40
• /
• 2002

Machining accuracy is affected by quasi-static errors of machining center. Since machine errors have a direct influence upon both the surface finish and geometric shape of the finished workpiece, it is very important to measure the machine errors and to compensate these errors. The laser measurement method for identifying geometric errors of machine tool has the disadvantages such as high cost, long calibration time and usage of volumetric error synthesis model. Accordingly, this paper deals with analysis of the geometric errors of a machine tool using ball bar test without using complicated error synthesis model. Statistical analysis method was adopted in this paper for deriving geometric errors using hemispherical helix ball bar test. As a result of experiment, geometric errors of the vertical machining center are compensated by 88%.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.27 no.11
• /
• pp.1572-1578
• /
• 2003

Particle Image Thermometry(PIT) with liquid crystal tracers is used for visualizing and analysis of the bubbly flow in a vertical temperature gradient. Quantitative data of the temperature were obtained by applying the color-image processing to a visualized image, and neural-network was applied to the color-to-temperature calibration. This paper describes the method, and presents the transient mixing temperature patterns of the bubbly flow.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1998.10a
• /
• pp.159-166
• /
• 1998

• Journal of Korea Multimedia Society
• /
• v.13 no.3
• /
• pp.410-416
• /
• 2010

This paper presents the auto-extraction method that searches for the Mapping points in the calibration algorithm of the image acquired by the wide angle CCD camera. In this algorithm, we remove the noise from the distorted image and then obtain the edge image. Proposed method extracts the distortion point, comparing the threshold value of the histogram of the horizontal and vertical pixel lines in edge image. This processing step can be directly applied to the original image of the wide angle CCD camera output. Proposed method results are compared with hand-worked result image using the two wide angle CCD cameras having different angles with the difference value of the result images respectively. Experimental results show that proposed method can allocate the distortion-calibration constant of the wide angle CCD camera regardless of lens type, distortion shape and image type.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.16 no.3
• /
• pp.274-286
• /
• 2016

This paper presents a 4-channel multi-rate vertical-cavity surface-emitting laser (VCSEL) driver. In order to keep the output power constant with respect to the process, voltage, temperature (PVT) variations, this research proposes automatic power and magnitude. For the fast settling time, the high-speed 10-bit time-interleaved Flash-successive approximation analog to digital converter (Flash-SAR ADC) is proposed and shared for automatic power and magnitude calibration to reduce the die area and power consumption. This chip is fabricated using $0.13-{\mu}m$ CMOS technology and the die area is $4.2mm^2$. The power consumption is 117.84 mW per channel from a 3.3 V supply voltage at 10 Gbps. The measured resolution of bias /modulation current for APC/AMC is 0.015 mA.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.15 no.1
• /
• pp.33-38
• /
• 2003

Turbidity meter calibrations were conducted using bottom sediment and suspended material collected with a vertical array of sediment traps at the coastal water off Gaduk Island. Compared to the bottom sediment comprising sand fraction of approximately 6％, trapped suspended material was composed entirely of silt and clay fractions and showed a tendency to get finer as elevation from the sea-bed increases. Slope parameter of linear regression due to bottom sediment was of minimum value and values of those due to suspended material increased gradually as the height of sediment trap increases (i.e., sediment size decreases). This result shows that turbidity meter calibration using bottom sediment can cause an overestimation error in the calculation of suspended sediment concentration and that the error can reach up to 25% in case of this study. Therefore, it is suggested that the use of a corrected calibration curve based on grain size distribution of suspended material instead of bottom sediment may reduce the measurement error of suspended sediment concentration.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.03a
• /
• pp.628-635
• /
• 2008

A series of cone penetration tests in large calibration chamber were performed to investigate the effect of cementation level, relative density and vertical confining stress on cone resistance. From the experimental results, it was observed that the cone resistance is increased with increasing gypsum content, relative density, and confining stress. The increasing ratio on cone resistance of cemented sand compared with that of uncemented sand, that is IR($q_c$), was increased with increasing gypsum content and relative density, whereas it was decreased as the vertical confining stress increases. It was also observed that the cementation of granular soil influences the behavior of ground at low level of confining stress and its effect is diminished with depth.