• 항공우주시스템공학회지
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• 제8권4호
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• pp.39-43
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• 2014

This paper examines the statistical process that should be performed with caution in the composite material qualification and equivalency process, and describes statistically significant considerations on outlier finding and handling process, data pooling through normalization process, review for data distributions and design allowables determination process for structural analysis. Based on these considerations, the need for guidance on statistical process for aircraft manufacturers who use the composite material properties database are proposed.

• Design & Manufacturing
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• 제14권2호
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• pp.7-13
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• 2020

For one decades, mobile devices components were made with plastic material, but environmental problems have recently replaced them with metal materials such as aluminum. Generally, aluminum components are mostly produced through cutting, but this process has limitations such as productivity and chip recycling. For this reason, many researches are conducted to improve productivity by replacing with the forging press process for manufacturing mobile device components. After forging process, the flash is remained and it is necessary to eliminate the flash from the final shape of components. In this paper, one-sided clearance for blanking aluminum material wes selected for parameter affected to the dimensional precision. Because the clearance is the most important parameter in blanking process. Deriving the clearance of blanking process for high dimensional precision, five level of one-sided clearance is selected and CAE is used to analyze the dimensional precision for each case.

• 정보화연구
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• 제10권3호
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• pp.295-303
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• 2013

This paper presents a new approach to managing dynamic business process changes based on business process change patterns. We identify and categorize business process change patterns that occur recurrently in a dynamic business environment. Several issues regarding management of process versions are discussed, and a pattern-based version management method for handling process changes more flexibly is explained in detail. We propose a mechanism for abstract process execution with runtime encapsulation of a business process, which can maximize the flexibility of process execution using multiple process versions. In addition, we propose a concept of process promotion and demotion that can dynamically choose an actual version of the process at run-time. With our pattern-based process change management and versioning approach, it is expected that the flexibility and efficiency of BPM systems can be enhanced significantly.

• 한국산학기술학회논문지
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• 제14권12호
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• pp.6590-6596
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• 2013

Dimethyl Ether(DME) 제조공정에서 DME의 생산성을 높이기 위해서 이산화탄소를 반드시 제거해야 한다. 본 연구에서는 물리적 흡수제를 사용해서 이산화탄소를 제거할 수 있는 용매 흡수법과 막 분리법을 이용하여 이산화탄소를 제거하는 공정에 대해서 전산모사를 수행한 후, 공정 사이의 에너지 소모량을 비교하였다. 물리적 흡수제로는 메탄올을 사용한 Rectisol 공정, dimethyl ethers of polyethylene glycol를 사용한 Selexol 공정 및 N-methyl pyrrolidone를 사용한 Purisol 공정을 적용하였다. 전산모사를 수행하여 각 공정에서 소모된 에너지를 비교해 본 결과 Purisol 공정에서의 소요 동력이 Membrane 공정에 비해 97.55%, Rectisol 공정에 비해 91.71%, Selexol 공정에 비해 58.25% 감소하는 것을 알 수 있었다. 그러므로 DME 제조공정에 가장 적합한 이산화탄소 제거공정은 Purisol 공정이라 판단된다.

• 한국물환경학회지
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• 제37권6호
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• pp.433-441
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• 2021

The aim of this study was to optimize the ozonation and ceramic membrane integrated process for greywater reclamation. The integrated process is a repeated sequential process of filtration and backwash with the same ceramic membrane. Also, this study used ozone and oxygen gas for the backwashing process to compare backwashing efficiency. The study results revealed that the optimum filtration and backwash time for the process was 10 minutes each when comparing the filtrate flow and membrane recovery rate. The integrated process was operated at three different operating conditions with i) 10 minutes for filtration and 10 minutes for ozonation, ii) 10 minutes for filtration and 10 minute for oxygen aeration, and iii) continuous filtration without any aeration for synthetic greywater. The integrated process with ozone backwashing could produce 0.55 L/min of filtrate with an average of 18.42% permeability recovery, while the oxygen backwashing produced 0.47 L/min and 6.26%, respectively. And without any backwashing, the integrated process could produce 0.29 L/min. This shows that the ozone backwash process is capable of periodically recovering from membrane fouling. The resistance of the fouled membrane was approximately 34.4% for the process with ozone backwashing, whereas the resistance was restored by 10.8% for the process with oxygen backwashing. Despite the periodical ozone backwashing and chemical cleaning, irreversible fouling gradually increased approximately 3 to 4%. Approximately 97.6% and 15% turbidity and TOC were removed by ceramic membrane filtration, respectively. Therefore, the integrated process with ozonation and ceramic membrane filtration is a potential greywater treatment process.

• Journal of Pharmaceutical Investigation
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• 제37권6호
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• pp.329-338
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• 2007

The quality assurance issue of drug products is more important than the general product because it is highly related to the human health and life. In this reason, the regulatory guide lines have continuously been intensified all around the world. In order to achieve effective quality assurance and real-time product release (RTPR) of drug products, process analytical technology (PAT), which can analyze and control a manufacturing process, has been proposed from the United States. With the PAT process, we can obtain significant process features of materials, quality characteristics and product capabilities from a raw material to the final product in the real-time procedure. PAT can also be utilized to process validation using information system that can analyze the risk of drug products through out an entire product life-cycle. In this paper, we first offered a new concept for the off-line process design methods to prepare the improved quality assurance restrictions and a real-time control method by establishing an information system. We also introduced an automatic inspection system by obtaining surrogate variables based on drug product formulations. Finally, we proposed an advanced PAT concept using validation and feedback principles through out the entire life-cycle of drug product manufacturing processes.

• 대한지구과학교육학회지
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• 제4권2호
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• pp.89-101
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• 2011

Science, Mathematics, Engineering, and Technology (STEM) integrated education has been spotlighted as a new approach for promoting students' conceptual understanding and supporting their future career in STEM field. There is increasing evidence of the positive impact of using a whole design process that can be an example of STEM integrated activities to improve students' conceptual understanding and problem solving skills. However, there is a lack of information on how teachers should accomplish science and engineering integration activities in their classroom and what process they should pay attention. To answer this question, we research the relationship between an design process and students' conceptual understanding using an engineering design activity, called 'Save the Penguins', and study on how each step in an engineering design process in this activity enhance students' conceptual knowledge in science. We found that testing their prototypes and discussing with their peers were the most important process for students to understand and apply science concept for their design, even though the whole engineering design process (demonstration about radiation, discussion about examples in our lives, and testing and reviewing their prototypes, and making final design) helps the students understand the scientific concepts.

• Nuclear Engineering and Technology
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• 제41권1호
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• pp.91-98
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• 2009

The "3+3 Process" for safety critical software for nuclear power plants' I&C (Instrumentation and Control system) has been developed in this work. The main idea of the "3+3 Process" is both to simplify the software development and safety analysis in three steps to fulfill the requirements of a software safety plan [1]. The "3-Step" software development process consists of formal modeling and simulation, automated code generation and coverage analysis between the model and the generated source codes. The "3-Step" safety analysis consists of HAZOP (hazard and operability analysis), FTA (fault tree analysis), and DV (design validation). Put together, these steps are called the "3+3 Process". This scheme of development and safety analysis minimizes the V&V work while increasing the safety and reliability of the software product. For assessment of this process, validation has been done through prototyping of the SDS (safety shut-down system) #1 for PHWR (Pressurized Heavy Water Reactor).

• 시스템엔지니어링학술지
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• 제2권2호
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• pp.27-32
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• 2006

The emerging standards since 1990's can be classified as 'system standards' (process-oriented standards) and they specify the process of an enterprise and also apply to almost all industries regardless of size, type and products. Notice that the conventional specification-oriented standards present relatively clear criteria even though the structure, performance, and terminology are defined in text-based form. However, the system standards dealing with the processes do not present a coherent guide. Therefore, it is difficult to analyze them with the same viewpoint, thereby resulting in differences in the level of understanding. This study is aimed at graphically modeling the system standards originally described in text-based form. The study has been carried out in the framework of the PMTE (Process, Methods, Tools, and Environment) paradigm. The system standard targeted here is ISO/IEC 15288. Firstly, review of the literature on the systems engineering (SE) standard/process and on the graphic model IDEF0 was done, respectively, for the parts of 'E' and 'M'. Then the SE process of the MIL-STD 499B was applied to ISO/IEC 15288 as 'P'. Finally, the graphical model was generated by AI0Wins as 'T'. As a result, the graphical model-based approach can complement the drawbacks of the text-based form.

• Korean Journal of Chemical Engineering
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• 제35권12호
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• pp.2327-2335
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• 2018

Fluid catalytic cracking (FCC) is an important chemical process that is widely used to produce valuable petrochemical products by cracking heavier components. However, many difficulties exist in modeling the FCC process due to its complexity. In this study, a dynamic process model of a FCC process is suggested and its structural observability is analyzed. In the process modeling, yield function for the kinetic model of the riser reactor was applied to explain the product distribution. Hydrodynamics, mass balance and energy balance equations of the riser reactor and the regenerator were used to complete the modeling. The process model was tested in steady-state simulation and dynamic simulation, which gives dynamic responses to the change of process variables. The result was compared with the measured data from operating plaint. In the structural analysis, the system was analyzed using the process model and the process design to identify the structural observability of the system. The reactor and regenerator unit in the system were divided into six nodes based on their functions and modeling relationship equations were built based on nodes and edges of the directed graph of the system. Output-set assignment algorithm was demonstrated on the occurrence matrix to find observable nodes and variables. Optimal locations for minimal addition of measurements could be found by completing the whole output-set assignment algorithm of the system. The result of this study can help predict the state more accurately and improve observability of a complex chemical process with minimal cost.