• 품질경영학회지
• /
• 제41권4호
• /
• pp.725-735
• /
• 2013

Purpose: The purpose of this study is to propose an Integrated Safety Evaluation Process (ISEP) that can enhances the safety aspect of the safety-critical system. This process utilizes the advantages of the iterative Systems Engineering process combined with the safety assessment process that is commonly and well defined in many standards and/or guidelines for railway, aerospace, and other safety-critical systems. Methods: The proposed process model is based on the predefined system lifecycle, in each phase of which the appropriate safety assessment activities and the safety data are identified. The interfaces between Systems Engineering process and the safety assessment process are identified before the two processes are integrated. For the integration, the elements at lower level of Systems Engineering process are combined with the relevant elements of safety assessment process. This combined process model is represented as Enhanced Functional Flow Block Diagram (EFFBD) by using CORE(R) that is commercial modelling tool. Results: The proposed model is applied to the lifecycle and management process of the United States aircraft system. The US aircraft systems engineering process are composed of twelve key elements, among which the requirements management, functional analysis, and Synthesis processes are considered for examplenary application of the proposed process. To synchronize the Systems Engineering process and the safety assessment process, the Systems Engineering milestones are utilized, where the US aircraft system has thirteen milestones. Taking into account of the nine steps in the maturity level, the integrated process models are proposed in some phases of lifecycle. The flows of processes are simulated using CORE(R), confirming the flows are timelined without any conflict between the Systems Engineering process and the safety assessment process. Conclusion: ISEP allows the timeline analysis for identifying activity and data flows. Also, the use of CORE(R) is shown to be effective in the management and change of process data, which helps for the ISEP to apply for the development of safety critical system. In this study, only the first few phases of lifecyle are considered, however, the implementation through operation phases can be revised by combining the elements of safety activities regarding those phases.

• 대한환경공학회지
• /
• 제30권12호
• /
• pp.1273-1280
• /
• 2008

본 연구에서는 섬유가공공정 중 머서화공정으로부터 가성소다액를 회수하기 위한 최적의 운전조건을 확립하고자 하였다. 주요 인자들로는 NF/RO막의 적용을 위해 세라믹 막을 이용하여 파울링 지수를 평가, 고분자 막의 적용을 위해 가성소다액의 회수율을 측정, 막의 재생율 향상, 화학세정 조건, 유기물부하, 탁도 및 색도의 최적 제거조건, 그리고 세라믹 막과 고분자막의 복합공정에서의 투과플럭스를 조사하였다. 결과에 따르면, 1단계 공정의 세라믹 한외여과막과 2단계 공정의 나노여과막은 총부유고형물, 잔류유기물, 색도를 포함한 탁도의 제거 그리고 가성소다 용액의 회수에 적합한 공정구성임을 확인하였다. 한외여과막만을 단독으로 사용했을 경우, 총 부유물질과 탁도를 99.0%이상 제거하였고, 색도와 TOC는 각각 74.7%와 49.2%의 제거효율을 얻을 수 있었다. 반면에 세라믹 UF+NF 복합막 공정에서는 총 부유물질과 탁도를 99.9%이상 제거할 수 있었고, 색도는 87.7%, TOC는 78.2%의 제거효율을 얻을 수 있었다. 특히, 복합막 공정에서는 83.7%의 부피회수율일 때 91.3% 가성소다를 성공적으로 회수 할 수 있었다. 이러한 측면에서 복합공정을 통해 가성소다 폐수로부터 순도 높은 가성소다액을 회수할 수 있었으며, 회수된 가성소다액은 공정 내에 재사용이 가능하여 경제적인 이득을 기대할 수 있다.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2009년도 하계학술발표대회 논문집
• /
• pp.183-188
• /
• 2009

RFID method is a non-contact automatic identification technology, which attaches microchips and antennas to an object in a tag form, to send and process information sent to the network using wireless frequency. Drying and curing process is extremely important which minimizes the resistivity of RFID antennas. This research is about the drying characteristic of conductivity ink, and analyzes and compares the hot-air drying process and infrared drying process. Also, the research was done for the improvement in drying performance by using combined process of hot-air and infrared mechanism. The experiment result shows that the hot-air or infrared drying system used alone cannot meet the required performance in drying printing method using conductivity ink. The combined drying system of hot-air and infrared ray showed resistance low enough in short drying and curing time, and this mechanism makes drying and curing process for mass and continuous production possible on-line.

• 한국정밀공학회지
• /
• 제19권9호
• /
• pp.118-124
• /
• 2002

The use of ceramic inserts in hot extrusion dies offers significant technical and economic advantages over other forms of manufacture. In this paper, process simulation and stress analysis are thus combined during the design, and a data exchange program has been developed that enables optimal design of the dies taking into account the elastic deflections generated in shrink fitting the die inserts and that caused by the stresses generated in the process. The shrink fit analysis has been performed that enables optimal design of the dies taking into account the elastic deflections which generated in shrink fitting the die inserts and that caused by the stresses generated in the process and by using DEFORM software for process analysis. This data can be processed as load input data for a finite element die-stress analysis. Process simulation and stress analysis are thus combined during the die design. The stress analysis of the dies is used to determine the stress conditions on the ceramic insert by considering contact and interference effects under both mechanical and thermal loads. The results are compared with the experimental ones for verification.

• 경영과학
• /
• 제28권3호
• /
• pp.73-82
• /
• 2011

Basel II advanced measurement approaches for operational risk need to estimate the frequency and severity distribution of operational losses. Due to lack of internal loss data, the estimation is impossible in many cases and so external loss data might be used by scaling on asset or gross income. To get around lack of loss data, scenario analysis combined with loss distribution approach can be useful in calculating the capital charge of operational risk. However, scenario based loss distribution approach requires much time and effort. Instead we may apply the analytic hierarchy process to measure operational risk of financial institutions. The analytic hierarchy process combined with loss distribution approach is to estimate the capital charge of operational risk in other areas based on the operational VaR in an area with sufficient loss data. AHP provides a tool for timely measurement of operational risk in this rapidly changing global environment.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
• /
• pp.106.2-106.2
• /
• 2010

IGCC (Integrated Gasification Combined Cycle) plants are among the most advanced and effective systems for electric energy generation. From a control perspective, IGCC plants represent a significant challenge: complex reactions, highly integrated control to simultaneously satisfy production, controllability, operability and environmental objectives. While all these requirements seem clearly to demand a multivatiable, model predictive approach, not many applications can be easily found in the literature. This paper describes the IGCC dynamic simulation that is capable of simulating plant startup, shutdown, normal, and abnormal operation and engineering studies. This high fidelity dynamic models contain the detailed process design data to produce realistic responses to process operation and upset. And the simulation is used by engineers to evaluate the transient performance and produce graphical information indicating the response of the process under study conditions.

• 한국펄프종이공학회:학술대회논문집
• /
• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.1
• /
• pp.37-42
• /
• 2006

The paper discusses the combined use of softwood and eucalyptus kraft pulps in the production of printing and writing papers. Looking for process and paper quality optimization, refining pilot plant trails were carried to identify the effects of refining type (mixed or separate) and intensities (specific edge load), and also furnish composition (amount of each pulp in mixture) on final paper quality and process costs. The basic effects on pulp fibers were evaluated against paper quality properties, such as physical strengths, bulk, vessel picking, opacity and porosity, as well as the interactions with papermaking process, such as estimates of paper machine runnability, paper breaks and industrial refining control. The results show that the furnish composition and the type of refining has a significant effect on properties related with both final paper quality and total costs. The best alternative for printing and writing papers was identified for mixed refining, under the lowest refining intensity, and with the highest dosage of eucalyptus pulp.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1997년도 추계학술대회논문집
• /
• pp.164-167
• /
• 1997

The die wear is one of the main factors affecting die accuracy and tool lifetime. It is desired to reduce die wear by developing simulation method to predict wear based on process parameters, and then optimize the process. Therefore, this paper describes disign methodology of preform for minimizing wear of finisher die in multi-stage cold forging processes. The finite element method is combined with the routine of wear prediction and the cold forging processes. The finite element method is combined with the routine of wear prediction and the cold forging process is analyzed. In order to obtain preform to minimize die wear, the FPS algorithm is applied and the optimal preform shape is found from iterative deformation analysis and wear calculation.

• 한국환경과학회지
• /
• 제20권2호
• /
• pp.231-239
• /
• 2011

Diethyl phthalate (DEP) and nonylphenol (NP) are widely spread in the natural environment as an endocrine disruption chemicals (EDs). Therefore, in this study, ultrasound (US) and ultraviolet (UVC), including $TiO_2$, as advanced oxidation processes (AOPs) were applied to a DEP and NP contaminated solution. When only the application of US, the optimum frequency for significant DEP degradation and a high rate of hydrogen peroxide ($H_2O_2$) formation was 283 kHz. We know that the main mechanism of DEP degradation is radical reaction and, NP can be affected by both of radical reaction and pyrolysis through only US (sonolysis) process and combined US+UVC (sonophotolysis) process. At combined AOPs (sonophotolysis/sonophotocatalysis) such as US+UVC and US+UVC+$TiO_2$, significant degradation of DEP and NP were observed. Enhancement effect of sonophotolysis and sonophotocatalysis system of DEP and NP were 1.68/1.38 and 0.99/1.17, respectively. From these results, combined sonophotocatalytic process could be more efficient system to obtain a significant DEP and NP degradation.

• 청정기술
• /
• 제12권3호
• /
• pp.151-156
• /
• 2006

염색폐수 처리를 위해 세라믹 정밀여과막 (MF)과 고분자 한외여과막 (UF)의 복합공정을 적용, 색도 및 유기물 (TOC) 제거율을 통해 공정을 최적화하고, 염색폐수의 분리효율을 조사하였다. 막 회복을 통한 운전 효율향상을 위해 역세척과 화학세정을 수행한 결과, 역세척에 의한 정밀여과막은 2분 주기로 1초 동안 역세척하였을때 투과수량이 10.3% 증가하였고, 한외여과막은 0.1% 수산화나트륨 용액으로 화학세정하였을 때 97%의 회복률을 나타내었다. 이때, 유기물, 색도, 부유물질(SS)의 제거율은 각각 84.6%, 97.4% 및 100%를 나타내었다. 분 복합공정의 적용은 염색폐수의 색도와 유기물 제거에 효과적임을 확인할 수 있었다.