• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.257-263
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• 2012

Biodiesel is a renewable energy which is nontoxic and acting as a replacement for conventional diesel which derived from fossil fuel. Classified biodiesel producing way such as acid, base, supercritical and enzyme methods, this study focused on eco-friendly production of biodiesel using supercritical and immobilized enzyme process. Assuming a plant with a production rate of 10,000 tons a year, a PRO II simulator program was used to simulate the product conversion rate and total energy consumption. The product conversion in supercritical process and immobilized enzyme was found to be 91.17% (including 0.9% glycerol) and 93.18% (including 1.0% glycerol) respectively. The result shows that the efficiency of immobilized enzyme process is higher compared to supercritical process but having lower end product purity. From the energy consumption point of view, supercritical process consume about 8.9 MW while immobilized enzyme process consume much lower energy which is 3.9 MW. Consequently, this study certifies that energy consumption of supercritical process is 2.3 times higher than immobilized enzyme process.

• Analytical Science and Technology
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• v.22 no.1
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• pp.35-43
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• 2009

The goal of PAT (Process Analytical Technology) is to build quality into products through better understanding and control of manufacturing processes, rather than merely testing the quality of the end product. Pharmaceutical manufacturers are trying to develop and implement new technologies in pharmaceutical production and quality control for real-time measurements of critical product and process parameters. Characterization of manufacturing process through experimental design, for evaluation of the effect of product and process variables, represents an integral part of the PAT framework. However, the publications regarding real PAT application to pharmaceutical process are very limited and the technologies are confidential as well. In this review, the case studies related to PAT are shown with real applications from a pharmaceutical company. Additionally, various applications of PAT on the developing stage are introduced with high analytical technologies for the improvement of quality control on manufacturing process.

• Design & Manufacturing
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• v.17 no.4
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• pp.72-78
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• 2023

Injection molding is a process widely used in various industries because of its high production speed and ease of mass production during the plastic manufacturing process, and the product is molded by injecting molten plastic into the mold at high speed and pressure. Since process conditions such as resin and mold temperature mutually affect the process and the quality of the molded product, it is difficult to accurately predict quality through mathematical or statistical methods. Recently, studies to predict the quality of injection molded products by applying artificial neural networks, which are known to be very useful for analyzing nonlinear types of problems, are actively underway. In this study, structural optimization of neural networks was conducted by applying multi-task learning techniques according to the characteristics of the input and output parameters of the artificial neural network. A structure reflecting the characteristics of each process step was applied to the input parameters, and a structure reflecting the quality characteristics of the injection molded part was applied to the output parameters using multi-tasking learning. Building an artificial neural network to predict the three qualities (mass, diameter, height) of injection-molded product under six process conditions (melt temperature, mold temperature, injection speed, packing pressure, pacing time, cooling time) and comparing its performance with the existing neural network, we observed enhancements in prediction accuracy for mass, diameter, and height by approximately 69.38%, 24.87%, and 39.87%, respectively.

• Journal of Korean Society for Quality Management
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• v.52 no.2
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• pp.185-199
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• 2024

Purpose: The improvement of yield and quality in product manufacturing is crucial from the perspective of process management. Controlling key variables within the process is essential for enhancing the quality of the produced items. In this study, we aim to identify key variables influencing product defects and facilitate quality enhancement in CNC machining process using SHAP(SHapley Additive exPlanations) Methods: Firstly, we conduct model training using boosting algorithm-based models such as AdaBoost, GBM, XGBoost, LightGBM, and CatBoost. The CNC machining process data is divided into training data and test data at a ratio 9:1 for model training and test experiments. Subsequently, we select a model with excellent Accuracy and F1-score performance and apply SHAP to extract variables influencing defects in the CNC machining process. Results: By comparing the performances of different models, the selected CatBoost model demonstrated an Accuracy of 97% and an F1-score of 95%. Using Shapley Value, we extract key variables that positively of negatively impact the dependent variable(good/defective product). We identify variables with relatively low importance, suggesting variables that should be prioritized for management. Conclusion: The extraction of key variables using SHAP provides explanatory power distinct from traditional machine learning techniques. This study holds significance in identifying key variables that should be prioritized for management in CNC machining process. It is expected to contribute to enhancing the production quality of the CNC machining process.

• Journal of the Ergonomics Society of Korea
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• v.31 no.1
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• pp.7-13
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• 2012

Objective: This paper discussed the characteristics of service design process by comparing with product design process. Background: Service design has different design outcomes, project participants, and design constraints than product design. Method: The comparison took two perspectives: one was shorter-term, design process of a service, and the other was longer-term, process of service development. Results: It was discussed that service design process is similar in overall, but has four differences. First, the role of design is required earlier and longer in the process, which means service designers need to participate from the begging of the project to service operation. Thus service designers are required to have holistic viewpoint of the project. Second, service design requires many design expertise thus collaboration needs to be well defined and managed throughout the process. Third, since service provider has limited resources, regulations, and market competition, some service features cannot be provided. Service designers are required to know both customers' needs and functional constraints. Last, service design is highly coupled with service operation. Designing and providing service happens at the same time and evolves over time. Conclusion: Consequently it was asserted that the role of designers in service design is essential for success. In specific, the role of service design architect, who manages design process and design outcomes, is a new and important role in service design project.

• Journal of the Korea Society for Simulation
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• v.16 no.4
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• pp.67-75
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• 2007

Radio Frequency IDentification(RFID) is in the limelight of fields of military, delivery and library management as an alternative or barcode system. However, it is restricted within product manufacturing, sales and delivery. In this paper, we apply RFID technology into process, especially packing process management to gauge RFID applicability. To verify beneficial features of RFID, we simulate RFID-adopted packing process. As a result, we demonstrate the effectiveness of a RFID-based Process Improvement In manufacturing process. The results of performance evaluations demonstrate that the proposed RFID-based Process Improvement reduces the labour time, labour cost and material cost. Furthermore, we analyze the validity of RFID-based Process Improvement by RFID cost.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.2
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• pp.125-133
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• 2004

In order to test reflecting the features of a development methodology and domain, it is required to tailor process standards and perform testing according to the tailored process. However, since commercial testing tools support only a part of the tailored process, it is essential to either acquire or develop testing tools appropriate for a development environment. This paper proposes a method to develop a test process execution tool which has common features of standards, and variousness in methodologies and domains. ‘Test Process Execution Tool: Test PET’ which is a test process execution tool developed adapting the concept of product line. Our Test PET generates the test process suitable for the development methodology and domain and then executes the produced test process.

• International Journal of Quality Innovation
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• v.8 no.1
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• pp.137-153
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• 2007

Failure mode and effects analysis (FMEA) is a preventive technique in reliability management field. The successful implementation of FMEA technique can avoid or reduce the probability of system failure and achieve good product quality. The FMEA technique had applied in vest scopes which include aerospace, automatic, electronic, mechanic and service industry. The marking process is one of the back ends testing process that is the final process in semiconductor process. The marking process failure can cause bad final product quality and return although is not a primary process. So, how to improve the quality of marking process is one of important production job for semiconductor testing factory. This research firstly implements FMEA technique in laser marking process improvement on semiconductor testing factory and finds out which subsystem has priority failure risk. Secondly, a CCD position solution for priority failure risk subsystem is provided and evaluated. According analysis result, FMEA and CCD position implementation solution for laser marking process improvement can increase yield rate and reduce production cost. Implementation method of this research can provide semiconductor testing factory for reference in laser marking process improvement.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.2
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• pp.87-92
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• 2015

The injection molding process is widely used in the production of most plastic products. In order to make metal-colored plastic products like those found in modern luxury home alliances, metallic pigments are mixed with a basic resin material for injection molding. However, process control for metal-colored plastic products is extremely difficult due to the non-uniform melt flow of the metallic resin pigments. In this study, the effect of process parameters on the quality of a metal-colored plastic product is evaluated. A rapid mold cooling method using a compressed cryogenic fluid is also proposed to decrease the content of undesired compounds within the plastic product.

• Korean Journal of Computational Design and Engineering
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• v.17 no.2
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• pp.111-122
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• 2012

Capacity planning plays an important role not only for master production plan but also for facility or layout design in shipbuilding. Product work breakdown structure, attributes of production resources, and production method or process data are associated in order to make the discrete event simulation model of shipyard layout plan. The production amount of each process and the process time is assumed to be stochastic. Based on the stochastic discrete event simulation model, the production capacity of each facility in shipyard is estimated. The stochastic model of product arrival time, process time and transferring time is introduced for each process. Also, the production capacity is estimated for the assumed master production schedule.