• Journal of Power Electronics
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• v.18 no.2
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• pp.482-491
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• 2018

The practical design methodology of a three-phase dual active bridge (3ph-DAB) converter applied to low voltage direct current (LVDC) applications is proposed by using a mathematical model based on the steady-state operation. An analysis of the small-signal model (SSM) is important for the design of a proper controller to improve the stability and dynamics of the converter. The proposed lead-lag controller for the 3ph-DAB converter is designed with a simplified SSM analysis including an equivalent series resistor (ESR) for the output capacitor. The proposed controller can compensate the effects of the ESR zero of the output capacitor in the control-to-output voltage transfer function that can cause high-frequency noises. In addition, the performance of the power converter can be improved by using a controller designed by a SSM analysis without additional cost. The accuracy of the simplified SSM including the ESR zero of the output capacitor is verified by simulation software (PSIM). The design methodology of the 3ph-DAB converter and the performance of the proposed controller are verified by experimental results obtained with a 5-kW prototype 3ph-DAB converter.

• Korean Journal of Construction Engineering and Management
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• v.12 no.4
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• pp.50-58
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• 2011

Lean concept is management philosophy that defines a customer's value and eliminates wasteful and impeditive factors. Management philosophy of Lean in the construction industry is referred to as "Lean Construction". Now this concept has expanded to achieve effective productivity during the design phase. Currently the norm of the domestic design process has been Point-based Design(PBD). It involves selecting a single structurally-feasible design option early and then refining that single design as more information becomes available throughout the design process. This single design is then re-worked until a solution is found that is feasible for all parties. On the contrary, Set-based Design(SBD) is based on lean processes to eliminate waste and improve project productivity. It focuses on keeping the design space as open as long as possible, to allow "subdesign" to advance and not labeling them as secondary in importance. Preserving the maximum number of feasible designs as long as possible reduces the likelihood that rework will be necessary and allows all project participants to utilize their unique expertise to make the project successful. This study proposes that the design methodology of minimizing waste and increasing productivity through SBD of AHP, one of the decision making process so as to compare PBD with SBD and tries to find decision making process and then suggest that application methodology through performs case study of SBD process.

• Journal of Environmental Science International
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• v.23 no.3
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• pp.359-368
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• 2014

The aim of our research was to apply experimental design methodology in the optimization of N, N-Dimethyl-4-nitrosoaniline (RNO, which is indictor of OH radical formation) degradation using gas mixing-circulation plasma process. The reaction was mathematically described as a function of four independent variables [voltage ($X_1$), gas flow rate ($X_2$), liquid flow rate ($X_3$) and time ($X_4$)] being modeled by the use of the central composite design (CCD). RNO removal efficiency was evaluated using a second-order polynomial multiple regression model. Analysis of variance (ANOVA) showed a high coefficient of determination ($R^2$) value of 0.9111, thus ensuring a satisfactory adjustment of the second-order polynomial multiple regression model with the experimental data. The application of response surface methodology (RSM) yielded the following regression equation, which is an empirical relationship between the RNO removal efficiency and independent variables in a coded unit: RNO removal efficiency (%) = $77.71+10.04X_1+10.72X_2+1.78X_3+17.66X_4+5.91X_1X_2+3.64X_2X_3-8.72X_2X_4-7.80X{_1}^2-6.49X{_2}^2-5.67X{_4}^2$. Maximum RNO removal efficiency was predicted and experimentally validated. The optimum voltage, air flow rate, liquid flow rate and time were obtained for the highest desirability at 117.99 V, 4.88 L/min, 6.27 L/min and 24.65 min, respectively. Under optimal value of process parameters, high removal(> 97 %) was obtained for RNO.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.337-338
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• 2006

The requirement to reuse a design knowledge have been enlarged with the automation of a design system. A design knowledge gives logical and technical meanings to design data of a problem area. The representation of the knowledge is distributed and developed independently. For this reason, we need a general methodology with a semantic interoperability of design knowledge. In this paper, we accept previous requirements by using semantic query system with ontology repository.

• Journal of Appropriate Technology
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• v.5 no.2
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• pp.82-90
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• 2019

The Box-Benhken Design (BBD) model of response surface methodology (RSM) was used to optimize fluoride adsorption conditions in water using a 350℃ thermally treated cow bone. Water temperature, pH, contact time, and initial fluoride concentration were selected as variables to be optimized. A second order reaction equation was obtained from a Box-Behnken Design DoE experimental matrix of 29 runs. R² and p-value of the model were 0.9242 and <0.0001, respectively, indicating that the selected variables had a very substantial effect on the adsorption results. The optimized adsorption capacity of the thermally synthesized bone char was estimated to be 6.46 mgF/g at the water temperature of 39.68℃, pH 6.25, contact time of 88.81 minutes and an initial fluorine concentration of 14.64 mgF/L.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.742-747
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• 2005

A model, which can analyze the hydrological performance for small hydropower(SHP) plants having no flow duration characteristics has been studied and developed. System performance of existing SHP plant under operating was analyzed by using the developed model. The annual operational rate of SHP plant showed that the data were in good agreement with predicted results from the model. Based on these results, several SHP sites to be exploited were selected and the performance characteristics were analyzed by using the developed model. Also, primary design values such as design flow rate, plant capacity, and operational rate were suggested. As a result, it was found that the methodology used in this study is useful tool to predict the hydrological system performances of SHP sites.

• Journal of Korean Society for Quality Management
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• v.4 no.1
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• pp.13-19
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• 1976

In the quality planning phase, the techniques for measuring cost-quality trade-offs are used for the selection of the optimal design specifications when design flexibility permits significant trade-offs to be made. But the product quality is not only depends on the developing cost, but also the time for developing that product. Therefor it is important to seek a methodology for estimating time-cost-quality trade-offs associated with the quality planning projects. This paper is aimed to find a methodology of time-cost-quality trade-offs and to develop a proper algorithm.

• Journal of the Korea Safety Management & Science
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• v.6 no.4
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• pp.99-106
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• 2004

In developing criteria for establishing workstation reach limits, it is essential to select the appropriate anthropometric stereotype for solving a specific design problem. The most important factor for comfortable workstation is to eliminate trunk flexion from the neutral (upright) posture. A solution to this design can be developed using population stature and link length data. This paper provides a methodology for design of comfortable workstation using anthropometric stereotype. Application of this methodology can be utilized in various designs for work space including standing and sitting workplace. For the purpose of this study, the data are measured by some parts on body such as stature, arm length, wrist height, elbow height, and shoulder hight. The samples for this study are randomly chosen from university students in Seoul and Kangnung during sixteen months (2003.3-2004.6).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1C
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• pp.46-54
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• 2006

The design method of synthetic aperture radar processor (SARP) in the critical design stage is to describe the processing algorithm, to estimate the fractional errors, and to set out the software (SW) and hardware (HW) mapping. The previous design methods for SARP are complex and depend on HW. Therefore, this paper proposes a critical design method that is of more general and independent of HW. This methodology can be applied for developing the space-based SARP using range-Doppler algorithm (RDA).

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2007.11a
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• pp.358-373
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• 2007

In this paper, we proposed the next generation mobile convergence service business model creation methodology. In order to establish such a business model creation methodology framework, we first introduce the service model based on our previous research results on next generation mobile convergence services. The service model contains several components such as infrastructures, operations, and provision of services that are indispensible for providing the next generation mobile services. Finally, by adding service and value flows to the developed service model, we propose the next generation mobile services business model creation methodology. To achieve this objective, we first derive necessary components of business model including actors, their relationships, and roles. In addition, we propose service composition methodology for creating new mobile services and its corresponding business models.