• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.16 no.2
• /
• pp.195-202
• /
• 1998

In this study, we utilized various type of GPS observation measurements to get a camera projection center of the aerial triangulation and consequently to determine which type is acceptable. For the accuracy and the error analysis, comparison between a projection center from the conventional model adjustment and the result determined by the kinematic DGPS positioning which is fitted to the conventional model adjustment using 3D conformal transformation method has been made. The camera projection center is located within a $\pm{2m}$ for C/A code range measurements, $\pm{14cm}$ for L1 phase measurements and $\pm{10cm}$ for L1/L2 phase measurements with $1\sigma$. In this way, the accuracy of the camera projection center by the bundle block adjustment can be predicted.

• ETRI Journal
• /
• v.33 no.4
• /
• pp.506-516
• /
• 2011

In this paper, we develop a registration method to eliminate the geometric inconsistency between the stereo-images and light detection and ranging (LIDAR) data obtained by an airborne multisensor system. This method consists of three steps: registration primitive extraction, correspondence establishment, and exterior orientation parameter (EOP) adjustment. As the primitives, we employ object points and linked edges from the stereo-images and planar patches and intersection edges from the LIDAR data. After extracting these primitives, we establish the correspondence between them, being classified into vertical and horizontal groups. These corresponding pairs are simultaneously incorporated as stochastic constraints into aerial triangulation based on the bundle block adjustment. Finally, the EOPs of the images are adjusted to minimize the inconsistency. The results from the application of our method to real data demonstrate that the inconsistency between both data sets is significantly reduced from the range of 0.5 m to 2 m to less than 0.05 m. Hence, the results show that the proposed method is useful for the data fusion of aerial images and LIDAR data.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.5 no.2
• /
• pp.109-120
• /
• 1985

This thesis is a study on multiple close range photogrammetry, and the purpose of this study is to develop the most accurate adjustment method of three dimensional object coordinates. This was achieved by comparing the standard errors of actual data to the computed values from 2 photos and multiple photos. The conventional methods for multiple photos have been analyzed by using geometric model formation. But in this study, the equation of collinearity condition which has been applied to aerial photogrammetry was derived to be a basic principle of close range photogrammetry, and the algorithm for analyzing multiple photos was developed using simultaneous bundle adjustment. The method used in this study, showed more homogeneous accuracy in coordinate and more consistent variance of error than those of conventional methods. It was found that the cases using 3, 4, and 5 photos were more accurate than using 2 photos; the accuracies were improved to 15%, 35%, and 50%, for each case. Thus this study is expected to be useful in measuring the geometry of historic monuments and other structures requiring high accuracy. Also the combined case of multiple photos is considered to be effective for the precise analysis of the objects which are difficult to measure for obstacles.

• Journal of Korean Society for Geospatial Information Science
• /
• v.23 no.2
• /
• pp.27-38
• /
• 2015

In this study, the 3D position coordinates were calculated for the targets using DLT and self-calibration bundle adjustment with additional parameters in close-range photogrammetry. And then, the accuracy of the results were analysed. For this purpose, the results of camera calibration and orientation parameters were calculated for each images by performing reference surveying using total station though the composition of experimental conditions attached numerous targets. To analyze the accuracy, 3D position coordinates were calculated for targets that has been identically selected and compared with the reference coordinates obtained from a total station. For the image coordinate measurement of the stereo images, we performed the ellipse fitting procedure for measuring the center point of the circular target. And then, the results were utilized for the image coordinate for targets. As a results from experiments, position coordinates calculated by the stereo images-based photogrammetry have resulted out the deviation of less than an average 4mm within the maximum error range of less than about 1cm. From this result, it is expected that the stereo images-based photogrammetry would be used to field of various close-range photogrammetry required for precise accuracy.

• Journal of Korean Academy of Nursing
• /
• v.26 no.4
• /
• pp.917-929
• /
• 1996

The purpose of this study is to explore types of postpartum depression and to understand the nature and structure of the postpartum depression by using Q-methodological approach. As a way of research, 55 statements concerning postpartum depression were selected through individual interviews with postpartum mothers and literature review. 30 women were chosen as a subject group for the study, with opinions shown in 55 statements divided into 9 scales by forced distribution. PC QUANL Program was used for analysis and Q-factors were analyzed by using principal component analysis. As a result, postpartum depression experience was classified into 5 types. There are "Role-Strain Type", "Unattributional Depression Type", "Psychosomatic Symptoms Type", "Self-Compassion Type", and "Role-Crisis Type". Type I was named "Role-Strain Type", referring to the strain generally experienced by mothers with regard to the new role as a mother and as a social member. Type II was named "Unattributional Depression Type", referring to the symptom experienced by people who were in a state of vanity and a sense of loss. They often break into tears for no specific reasons. In case of Type III, people in a state of "Psychosomatic Symptoms Type" develop physical symptoms after suffering from inherent emotional conflict. Type IV was named "Self-Compassion Type" refers to the symptom shown by those who feel pity for their children and for themselves. And they show inability to cope with the reality properly. Type V was named "Role -Crisis Type", which is experienced by people who have a burden and a severe fear of their own job and their children in their mind, also showing serious conflict with maternal role. Futhermore, it was carried out to examine structure of postpartum depression in terms of degree of depression and adjustment ability. Type I showed mild degree of depression and relatively good adjustment ability. Type II showed broad range of degree in depression and moderate adjustment ability. Type III showed moderate depression and relatively low adjustment ability. Type IV revealed relatively serious degree of depression and the lowest adjustment ability. Type V revealed very serious degree of depression and the lowest adjustment ability. As a result, considering the structure of postpartum depression. Type I is considered to be a normal depression sympton which most mothers generally experience, followed by Type II, Type III, Type IV and Type V, each of which show increasingly worse degree of depression and lower adjustment ability. In conclusion, it seems to be it is necessary to understand distinct symptoms of postpartum depression and to examine the characteristics and structure of those types, so that it could lead to more individual nursing approach.cteristics and structure of those types, so that it could lead to more individual nursing approach.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.10b
• /
• pp.275-276
• /
• 2002

Active-head sliders with a unimorph piezoelectric actuator for flying height control were experimentally evaluated. It was found that the normalized stroke of the actuator is 5.2 to 6 nm/V/mm without flying over the disk. However, the normalized adjustment range of flying height is about 1.6 nm/V/mm when the active-head slider is flying over the disk. This value is smaller than the measured value when the slider is not flying, because of the air pressure generated at the active pad when the pad approaches the disk surface.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.1
• /
• pp.100-109
• /
• 2017

This paper proposes performance improvement schemes for sensorless PMSM control drive using a four-switch three-phase inverter (so-called B4 inverter). In the proposed scheme, the back-EMF estimation-based sensorless control algorithm is used to control the brushless PMSM without position sensors. In order to have stable operation, this paper presents a gain adjustment scheme that compensates the reduction of stable sensorless operation range as long as the rotor speed increases. In B4 topology, the center point of dc-link capacitors is connected to 3-phase load, and it is prone to have the load current distortion. Hence, to mitigate this problem, a distortion compensation scheme by modifying voltage commands using measured dc-link potentials is proposed in this paper. The validity of the proposed method is evaluated by simulations and experiments.

• International Journal of Fluid Machinery and Systems
• /
• v.5 no.1
• /
• pp.30-37
• /
• 2012

A two dimensional Darrieus-type turbine has been proposed for the hydropower utilization of extra-low head less than 2m. In a practical use of Darrieus-type hydro-turbine, head and flow rate may be varied temporally and seasonally. Considering that the cost advantage is required for the low head hydro turbine system, the Darrieus turbine should be operated with high efficiency in the wider range of flow rate possibly by using an additional device with simpler mechanism. In the present paper, an adjustment of inlet nozzle section by lowering the inlet nozzle height is proposed to obtain the preferable inlet velocity in low flow rate conditions. Effects of resulting spanwise partial inlet flow are investigated. Finally, an effective modification of inlet nozzle height over flow rate variation is shown.

• IE interfaces
• /
• v.22 no.3
• /
• pp.263-277
• /
• 2009

This research deals with a task assignment problem to worker group which consists of one master and one assistant. Each task must be assigned to only one worker group and it is possible to make a pair of each master and each assistant to organize a worker group. A worker group may have more than one task assigned to it, but the workloads of each worker group must be balanced within the allowable range. This problem can be formulated mathematically using the Mixed Integer Programming(MIP), where the objective function is to minimize the total assignment cost. A two phase heuristic algorithm is suggested in order to find approximate solutions. The first phase is to obtain an initial solution, where the initial assignment is performed to follow the workload adjustment. In the second phase, the solution is improved through the repeated process of the exchange and the assignment adjustment. Numerical experiments have been performed to evaluate the performance of the heuristic algorithm.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.24 no.63
• /
• pp.1-12
• /
• 2001

When designing the parameter on the multiple quality characteristics, there has been a study for optimization of problems, but there has been few former study on the possible conflicting phenomena in consideration of the correlations among the characteristics. To solve the issue on the optimal design for multiple quality characteristics, this study propose the expected loss function with cross-product terms among the characteristics and derived range of the coefficients of the terms. The model will be used to determine the global optimal design parameters where there exists the conflict among the characteristics, which shows difference in optimal design parameters for the individual characteristics. Also, when an adjustment factor exists for each m performance characteristics, this research propose a method by minimizing the expected loss after adjustment.