• Journal of radiological science and technology
• /
• v.44 no.1
• /
• pp.1-8
• /
• 2021

The purpose of this study was to analyze the effect of automatic exposure control (AEC) control factors in digital radiography systems based on the fine contrast images using coin phantoms. The AEC control factors were targeted at the range of dominent zone, sensitivity, and density. The dominent zone was divided into cases where a single coin was used to cover the field configuration, and cases where seven coins were used to cover the field configuration. The sensitivity was classified into three stages (200, 400, 800) and the density was classified into three stages (2.5, 0, 2.5). Image quality was evaluated by signal to noise ratio (SNR) and contrast to noise ratio (CNR). Then, the automatically exposed tube current was measured. As a result, the X-ray image of seven coins obtained a result value of about 1.2 times higher for SNR and 1.9 times higher for CNR than the X-ray image for one coin. The tube current was also about 1.6 times higher. In conclusion, In AEC, the higher the field configuration and dominent zone are matched and the higher the density, the lower the sensitivity, which increases the tube current and CNR, which increases the image quality. Therefore, it is judged that the appropriate setting of the range of dominent zone, sensitivity, and density of the control, which is the AEC control factor, could improve the fine contrast of images.

• Journal of the Semiconductor & Display Technology
• /
• v.23 no.2
• /
• pp.1-5
• /
• 2024

In the electronics industry, a lot of research and development is being conducted on electronic component supply, component alignment and insertion, and automation of soldering on the back side of the PCB for automatic PCB assembly. Additionally, as the use of electronic components increases in the automotive component field, there is a growing need to automate the alignment and insertion of components with leads such as transistors, coils, and fuses on PCB. In response to these demands, the types of PCB and parts used have been more various, and as this industrial trend, the quantity and placement of automation equipment that supplies, aligns, inserts, and solders components has become important in PCB manufacturing plants. It is also necessary to reduce the pre-setting time before using each automation equipment. In this study, we propose a method in which a vision system recognizes the type of component and simultaneously corrects alignment errors during the process of aligning and inserting various types of electronic components. The proposed method is effective in manufacturing various types of PCBs by minimizing the amount of automatic equipment inserted after alignment with the component supply device and omitting the preset process depending on the type of component supplied. Also the advantage of the proposed method is that the structure of the existing automatic insertion machine can be easily modified and utilized without major changes.

• Korean Journal of Clinical Laboratory Science
• /
• v.36 no.2
• /
• pp.239-244
• /
• 2004

Recently automatic equipment has been well popularized for the erythrocyte sedimentation rate, a widely used test, but no standard quality control has been established yet. Thus, we are going to report a case that established and applied a quality control method using the TEST 1 automatic analyzer. For internal quality control, we adopted the repeatability test through comparison with daily mean check, with a manual method using patients' specimens and with the results of a test on the previous day. In order to set the tolerance standard for each quality control method, we compared the results of 50 specimens that showed a wide range of ESR results and examined correlation and differences according to result. After setting the tolerance standard, we applied the standard at tertiary university hospitals for 120 days and investigated positive rates and re-examination rates. If the tolerance standard was exceeded, the cause was also identified. We selected a specimen of below 25 mm/hr (T1), one between 26-50 mm/hr (T2) and one of over 51 mm/hr (T3) at random. The correlation between the manual method and the automatic method was quite high (r=0.98), and it is found appropriate to set based on differences in result values below 25 mm/hr, the upper limit of the reference value, and based on differences in the percentage of result values above 25 mm/hr. Accordingly, we set the criteria for rejection above 10 mm/hr and above 20%. When the criteria were applied in the laboratory, 1.7% of specimens in the range of T1, 8.3% of those in the range of T2 and 7.5% of those in the range of T3 were rejected. Because all the rejected ones fell within the tolerance limit in re-examination calibration verification was not carried out. With the wide popularization of erythrocyte sedimentation rate analyzers that can carry out a lot of tests quickly using automatic methods, it is necessary to improve the reliability of test results by establishing internal quality control policies. We expect that an agreed standard quality control method may be established based on the method proposed in this study.

• Journal of Institute of Control, Robotics and Systems
• /
• v.18 no.7
• /
• pp.673-679
• /
• 2012

This paper introduces robust tracking algorithm for fast and erratic moving object. CAMSHIFT algorithm has less computation and efficient performance for object tracking. However, the method fails to track a object if it moves out of search window by fast velocity and/or large movement. The size of the search window in CAMSHIFT algorithm should be selected manually also. To solve these problems, we propose an efficient prediction technique for fast movement of object using Kalman Filter with automatic initial setting and variable configuration technique for search window. The proposed method is compared to the traditional CAMSHIFT algorithm for searching and tracking performance of objects on test image frames.

• Journal of Korean Society for Quality Management
• /
• v.29 no.3
• /
• pp.66-78
• /
• 2001

This paper deals with problem of determining process target value under automated visual inspection(AVI) system. Three independent error sources - digitizing error, illumination error, and positional error - which have a close relationship with the performance of the AVI system, are considered. Assuming that digitizing error is uniformly or normally distributed and illumination and positional errors are normally distributed, respectively, the distribution function for the error of measured lengths is derived when the length of a product is measured by the AVI system. Then, Optimal target values under two error models of AVI system are obtained by minimizing the total expected cost function which consists of give away, rework and penalty cost. To validate two process setting models, AVI system for drinks filling process is made up and test results are discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1993.10a
• /
• pp.375-380
• /
• 1993

We developed a part of stroke sensing cylinder and its measurement system for system for automatic excavator. In this paper, for development of stroke sensing sylinder, we consist of 2-axis control instrument system with magnetic sensor. A Performence of cylinder rod with magnetic scales is evaluated by its system. Furthmore, the position control for good performance of instrument system is achieved by a sliding mode control which is a new method diminishing the chattering in that control by setting 2-dead band along the swtching line. The unknown parameters for sliding mode control are estimated by the signal compression method.

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.1410-1415
• /
• 2007

Recently introduced WBK(Wire-wounded Bulk Kagome) shows relatively superior mechanical properties compared to other types of PCM. WBK is fabricated by assembling helical wires in 6 directions. Wire being a helix, the wire's geometric properties like pitch and helical radius shows certain geometric characteristics which can play some critical role in setting up an automatic fabrication process. In this study, geometry of WBK is modeled by various transformations of a piece of helical wire and the characteristics of the geometry of an element of WBK truss are discussed. In addition, the roles of pitch and helical radius of wire in optimizing the assembling process are described and the derivation of criteria is attempted to decide proper helical radius which would maintain minimal interference between wires at the crossings.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2007.11a
• /
• pp.174-177
• /
• 2007

In this work, we researched static and dynamic characteristics concern to hydraulic regulator control process and parameter setting, which is used on liquid rocket engine regulation. The hydraulic regulator of 8K14 "SCUD" 9D21 engine is analyzed and on the basis of the developed mathematical modeling the analysis of response time and certification on automatic control accuracy is carried out. In this process, we find out specific design configuration of needle valve flow section that effects on pressure regulation performance.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.30A no.9
• /
• pp.71-79
• /
• 1993

This paper proposes a new test pattern generation methodology for combinational logic circuits using neural networks based on a modular structure. The CUT (Circuit Under Test) is described in our gate level hardware description language. By conferring neural database, the CUT is compiled to an ATPG (Automatic Test Pattern Generation) neural network. Each logic gate in CUT is represented as a discrete Hopfield network. Such a neual network is called a gate module in this paper. All the gate modules for a CUT form an ATPG neural network by connecting each module through message passing paths by which the states of modules are transferred to their adjacent modules. A fault is injected by setting the activation values of some neurons at given values and by invalidating connections between some gate modules. A test pattern for an injected fault is obtained when all gate modules in the ATPG neural network are stabilized through evolution and mutual interactions. The proposed methodology is efficient for test generation, known to be NP-complete, through its massive paralelism. Some results on combinational logic circuits confirm the feasibility of the proposed methodology.

• Journal of Industrial Technology
• /
• v.19
• /
• pp.179-187
• /
• 1999

The computer pattern sewing machine is an automatic sewing machine that is controlled by an input pattern. Even a novice can run this machine for various tasks fast and reliably such as sewing a button, a belt ring and an airbag, etc. The pattern processing software, which is the main software of this machine, is for editing and modifying pattern data by online teaching or off-line editing, setting up parameters, and calculate a moving distance of working area on the x-y axes. In this paper we propose an algorithm to generate pattern data for sewing by simplifying image data. The pattern data are composed of outline data like dot, line, circle, arc, curve, etc. We need converting this data into sewing data which involve sewing parameter, moving distance of working are an the x-y axes, thread, spindle speed.