• Journal of Power System Engineering
• /
• v.15 no.3
• /
• pp.65-69
• /
• 2011

This paper introduces the multi-coil eddy current sensor and its characteristic in magnetic material gas turbine rotor. In the past, magnetic particle inspection method was used for qualitative defect evaluation in magnetic material gas turbine rotor. And the ultrasonic inspection method was used for quantitative defect evaluation. Nowadays, eddy current method is used in magnetic gas turbine rotor inspection due to advanced sensor design technology. We developed multi-coil eddy current sensor for the rotor dovetail inspection. At first, rotor stress is analyzed for the determination of sensor position and number. The sensor coils are designed to cover the stress concentration area of rotor dovetail. We select optimum frequency according to material standard penetration data and experiment results. The rotor mock-up and artificial defects were made for the signal detection and resolution analysis of multi-coil eddy current sensor. The results show that signal detection and resolution capabilities are enhanced in comparison to the commercialized sensor enough for the gas turbine rotor inspection. So, this developed multi-coil eddy current sensor substituted for commercialized one and it applied in real gas turbine rotor inspection.

• Journal of Korean Society for Quality Management
• /
• v.20 no.2
• /
• pp.109-117
• /
• 1992

An inspection task largely can be seen as a job divided up into a series of visual search and classification subtasks. In these subtasks, an Inspector must performs to compare the standard references proposed in visual environments and recalled in his memory with the visual stimuli to be inspected. It means that the judgement of similarity should be demanded on inspection tasks. Therefore, the inspector's ability for the judgement of similarity and the difference similarity between inspection materials are important factors to effect on performances in inspection tasks. In this paper, to analysis the effect of these factors on inspection time, an inspection task is designed and suggested by means of computer simulator. Especially, the skin conductance responses(SCR) of subjects are measured to evaluate the complexity of tasks due to the difference of similarity between materials. In the results of experiment, the more similar or different the difference of similarity between materials is, the shorter the inspection time is because of the reduction of task complexity. And, When the inspector's cognition for similarity between materials is consistanct, the inpsection time is improved. Concludingly, the consistency of reponses for similarity judgement becomes a measurement to present the performance levels. And the information of inspection time that due to the difference of similarity between materials must be considered in planning and scheduling inspection tasks.

• Journal of the Institute of Convergence Signal Processing
• /
• v.22 no.4
• /
• pp.185-192
• /
• 2021

Various methods have been proposed to determine the defect detection of welding bead, and recently sensor data and image data inspection have been steadily announced. There are advantages that sensor data inspection is highly accurate, and two-dimensional-based image data inspection is able to determine the position of the welding bead. However, when analyzing only with sensor data, it is difficult to determine whether the welding has been performed at the correct position. On the other hand, the image data inspection does not have high accuracy due to noise and measurement errors. In this paper, we propose a method that can complement the shortcomings of each inspection method and increase its advantages to improve accuracy and speed up inspection by fusing sensor data inspection which are average current, average volt, and mixed gas data, and image data inspection methods and is implemented as software. In addition, it is intended to allow users to conveniently and intuitively analyze and grasp the results by performing analysis using a graphical user interface(GUI) and checking the data and inspection results used for the inspection. Sensor inspection is performed using the characteristics of each sensor data, and image data is inspected by applying a morphology geodesic active contour algorithm. The experimental results showed 98% accuracy, and when performing the inspection on the four image data, and sensor data the inspection time was about 1.9 seconds, indicating the performance of software that can be used as a real-time inspector in the welding process.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.6
• /
• pp.2452-2457
• /
• 2012

When a quality inspection process rejects a product unit, consecutive repeated inspections are sometimes conducted for the rejected unit to reduce a false reject possibility. This paper analyzes a special inspection process that allows up to two times of consecutive testing for each product to decrease type I inspection errors. This study uses a Markov chain to model the steps of the inspection process and a product unit's quality states during inspection. Historical inspection results from a company are used as the data for the Markov chain model. Using the Markov chain model and data, this study analyzes the effect of this special inspection rule on the proportion of the final quality levels and scrap rate. The results demonstrate that this inspection process of possible double testing could help reduce unnecessary rejects and consequently decrease material and production costs.

• Journal of Institute of Control, Robotics and Systems
• /
• v.21 no.8
• /
• pp.788-793
• /
• 2015

This paper proposes a path planning algorithm to reduce the inspection time of AOI (Automatic Optical Inspection) machines for SMT (Surface Mount Technology) in-line system. Since the field-of-view of the camera attached at the machine is much less than the entire inspection region of board, the inspection region should be clustered to many groups. The image acquisition time depends on the number of groups, and camera moving time depends on the sequence of visiting the groups. The acquired image is processed while the camera moves to the next position, but it may be delayed if the group includes many components to be inspected. The inspection delay has influence on the overall job time of the machine. In this paper, we newly considers the inspection delay time for path planning of the inspection machine. The unified approach using genetic algorithm is applied to generates the groups and visiting sequence simultaneously. The chromosome, crossover operator, and mutation operator is proposed to develop the genetic algorithm. The experimental results are presented to verify the usefulness of the proposed method.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.22 no.1
• /
• pp.150-155
• /
• 2013

This work present a new method of sealing inspection system for vehicle in which foam rubber materials are used for sealing the vehicle parts. This system is composed from a devices comprising non-contact and real-time scanning on visual inspection in machine parts. We have been investigated qualitative factors that influenced on sealing system of vehicle structure which flexibly attenuated vibration and plenty of foam rubber materials having elastic property. However, there are different factors which still depended on outdated technique (personnel subjective judgment) in the performance inspection of rubber parts, specially for cross section inspection. Through a newly developed inspection system which recently applied for the production line, we successfully achieved more effective results of matching rate by about 80 % in the sealing performance inspection with 0.7% to 1.4% in the repeated errors. These are resulted from non-contacted response by CCD camera and vision program using geometry matching method. We expect that this system may be widely applied in the strict inspection parts of more diverse cross-section in future.

• Corrosion Science and Technology
• /
• v.7 no.4
• /
• pp.208-211
• /
• 2008

Safety operation of main pipelines is primarily provided by anticorrosive monitoring. Anticorrosive monitoring of oil pipeline transportation objects is based on results of complex corrosion inspections, analysis of basic data including design data, definition of a corrosion residual rate and diagnostic of general equipment's technical condition. All the abovementioned arrangements are regulated by normative documents. For diagnostics of corrosion-technical condition of oil pipeline transportation objects one presently uses different methods such as in-line inspection using devices with ultrasonic, magnetic or another detector, acoustic-emission diagnostics, electrometric survey, general external corrosion diagnostics and cameral processing of obtained data. Results of a complex of diagnostics give a possibility: $\cdot$ to arrange a pipeline's sectors according to a degree of corrosion danger; $\cdot$ to check up true condition of pipeline's metal; $\cdot$ to estimate technical condition and working ability of a system of anticorrosive protection. However such a control of corrosion technical condition of a main pipeline creates the appearance of estimation of a true degree of protection of an object if values of protective potential with resistive component are taken into consideration only. So in addition to corrosive technical diagnostics one must define a true residual corrosion rate taking into account protective action of electrochemical protection and true protection of a pipeline one must at times. Realized anticorrosive monitoring enables to take a reasonable decision about further operation of objects according to objects' residual life, variation of operation parameters, repair and dismantlement of objects.

• The Korean Nurse
• /
• v.32 no.5
• /
• pp.78-92
• /
• 1994

The purposes of this study were to evaluate the results of the hospital self inspection with the medical insurance and to offer basic materials to the medical insurance inspection and the education of medical insurance. The study was undertaken with 4,730 cases among the total 13,810 medical insurance in patients from Jan. 1990 to Dec. 1990 at one university hospital in Pusan. The major contents of the inspection were the omission of diagnosis and medical fee, curtailment, application mistake, the rates of inclusion, subtraction and total accumulation. The data were collected using patients charts and bills. The results of the paper analysis were as follows. 1. From the pre-discharge hospital self inspection, major omission were treatment and material fee but medication fee were moderately high and high curtailment was operation fee. 2. Decreasing order of operation fee adjustment were digestive(22.4%) muscular(22%) and neuro system operation(21.4%). Majority of the medication fee adjustments were injection form of medication(95.7%). 50% of the treatment fee adjustments were composed of injection fee(27.9%) and dressing or post-operative dressing fee(22.3%). 74.7% of material costs were composed of oxygen(30.6%), blood and the blood composed materials(44.1%). 3. Pre-discharge inspection showed 6% adjustment rate, 4.3% addition and 2.1% curtailment rate. Most of the adjustment were omission(66.1%). 4. Omission were divided by event omission(92.6%)and application mistake(7.4%). The decreasing order of omission fee were operation(21.84%), treatment(18.71 %) diagnosis(18.68%), medication (14.53%) and material costs(10.84%). So operation and treatment part were the major part of the total omission fee(40.55%). 5. The average omission of diagnosis were 1,800 per month.

• Journal of Korean Society for Quality Management
• /
• v.29 no.4
• /
• pp.18-37
• /
• 2001

On this research, recognizing that ship inspection and audit services are closely related in Improving ship safety, the importance of active quality managements of ship inspection and audit services have been notified. For this research, based on previous research results, Quality managements of ship inspection and audit services were divided into the following aspects; the source of quality managements, execution of quality managements and outcome of quality managements. The results of this study is as follows. Overall, it is clearly shown that the elements of quality managements execution such as management responsibilities, resource management., product realization, measurement and analyzation, and improvement had also acted as a mediator between the relation of quality managements source and outcome.

• Journal of the Society of Naval Architects of Korea
• /
• v.57 no.1
• /
• pp.1-7
• /
• 2020

In general, an inspection schedule is established based on the long-term fatigue life during the design stage. However, in the design stage, it is difficult to clearly identify the uncertainty factors affecting long-term fatigue life. In this study, the probabilistic fatigue life assessment was conducted in accordance with the methodology of DNV-GL. Firstly, The initial crack distribution estimated through the initial crack propagation analysis was updated by reflecting the results of crack inspection. Secondly, the updated crack distribution was compared with the initial crack distribution, and the probability of failure was updated with the effect of crack inspection.