• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.4
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• pp.40-46
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• 2006

It is required to develop a highly reliable attitude & orbit control system of satellite that is less expensive as the technology of satellite design & integration is recently matured dramatically. To accomodate this kind of needs, the two axis attitude control method for wheel-based momentum-biased satellite system whose momentum bias vector points to a certain direction(sun direction), is developed using simple but reliable sensors and actuator: three axis magnetometer and coarse sun sensor are used as sensors, and magnetic torque bars are used as actuator. Classical PD type controller design methodologies are applied on a satellite system for the two axis control with the proper assumptions. Nonlinear simulation results are included to demonstrate the long term stability and the performance of closed-loop system design results.

• The Korean Journal of Applied Statistics
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• v.18 no.1
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• pp.159-171
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• 2005

The US Food and Drug Administration(FDA) recommends that population bioequivalence and individual bioequivalence would be assessed to address the prescribability and switchability between a brand-name drug and its new formulation or generic copy in its 2001 guidance document. The test for population bioequivalence in the latest FDA guidance is recommended in 2 x 4 crossover design, but it turns out to be very conservative. Recently Lee, Shao & Chow(2002), Chow, Shao & Wang(2003) and McNally, Iyer & Mathew(2002) proposed new statistical methods for assessing population bioequivalence between drugs to correct the biasness of current FDA method. Since 2 x 2 crossover experiment is most welcomed design in bioequivalence testing, we adopt their methods to 2 x 2 crossover designs and compare their methodologies with FDA one through the simulation study.

• Journal of Korean Society on Water Environment
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• v.23 no.1
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• pp.111-121
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• 2007

The experimental design and response surface methodologies haven been applied to the investigation of the chemical coagulation of livestock wastewater. The chemical coagulation reactions were mathematically described as a function of parameters raping mixing (rpm) of chemical coagulation ($X_1$), slow mixing (rpm) of chemical coagulation ($X_2$), $FeCl_3 $ concentration (mg/L) ($X_3$) and pH ($X_4$) being modeled by use of the central composite design. Empirical models were developed to describe relationship between the experimental variables and response. Statistical analysis indicates that three factors ($X_1$: raping mixing (rpm), $X_2$: slow mixing (rpm), $X_3$: $FeCl_3 $ concentration (mg/L) on the linear term (main effect), slow mixing (rpm) (${X_2}^2$) on the non-linear term (quadratic), and two factors ($X_1-X_3$, $X_2-X_3$) on the non-linear term (cross-product) had significant effects, respectively. The estimated ridge of maximum responses and optimal conditions for CODcr using canonical analysis was 87.44% ($X_1$: 229 rpm, $X_2$: 51 rpm, $X_3$: 877 mg/L, $X_4$: 4.3). To confirm this optimum condition, three additional experiments were performed and the mean CODcr removal (%) and concentration (mg/L) with a standard deviation of $87{\pm}1.2%$ ($576{\pm}34ppm$) were obtained.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.10
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• pp.175-185
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• 1998

In this paper, we studied some design methodologies of typical FIR filters based on the peak-error constrained least square criterion which was first introducedd by Adams in 1991. This method is a mixed type of the classical least squared error method(LSM) and the so-called min-max error method (MMM). And by considering both the least squared error as well as the maximum error, the solution, i.e. the impulse response of the filter, can be found only when the restrictions on maximum gain, transition bandwidth, and the squared error are satisfied simultaneously under some trade-off conditions. We used the multiple exchange algorithms for optimization procedure and applied the design methodology to the cases of the multiband filter, the differentiator, and the Hilbert transformer by taking the balance of two design criteria into account. The results show that the peak-error constrained least weighted square error design method(PLEM) is superior in performance to the existing LSM and MMM from both the squared error and the maximum error standpoints. And it is verified that PLEM can be applied to not only the case of simple low pass filter, but also to various types of FIR filters.

• Journal of Hydrogen and New Energy
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• v.24 no.1
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• pp.50-60
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• 2013

High temperature proton exchange membrane fuel cells (PEMFCs) using phosphoric acid (PA) doped polybenzimidazole (PBI) membranes have been concentrated as one of solutions to the limits with traditional low temperature PEMFCs. However, the amount of reported experimental data is not enough to catch the operational characteristics correlated with cell performance and durability. In this study, design of experiments (DOE) based operational optimization method for high temperature PEMFCs has been proposed. Response surface method (RSM) is very useful to effectively analyze target system's characteristics and to optimize operating conditions for a short time. Thus RSM using central composite design (CCD) as one of methodologies for design of experiments (DOE) was adopted. For this work, the statistic models which predict the performance and degradation rate with respect to the operating conditions have been developed. The developed performance and degradation models exhibit a good agreement with experimental data. Compared to the existing arbitrary operation, the expected cell lifetime and average cell performance during whole operation could be improved by optimizing operating conditions. Furthermore, the proposed optimization method could find different new optimal solutions for operating conditions if the target lifetime of the fuel cell system is changed. It is expected that the proposed method is very useful to find optimal operating conditions and enhance performance and durability for many other types of fuel cell systems.

• Korean Institute of Interior Design Journal
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• v.21 no.5
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• pp.280-288
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• 2012

The objective of this study was to analyze the characteristics of traditionality expressions at modernized Chinese restaurant in Hong Kong. As a case study, the study examined 12 modernized Chinese restaurants in Hong Kong. The gathered data were categorized and examined according to the ways of traditionality expressions, which included reproduction, transformation, and reinterpretation of traditional components. Each of the components was measured for the amount of traditional or modernity expression on a five-point scale. The five-point scoring system put an emphasis on tradition; 1 point was given to principal modernity(modernity: 90-100% + tradition: 0-10%), 2 points were given to principal modernity + auxiliary tradition(modernity: 70-90% + tradition: 10-30%), 3 points were given to the same ratio between tradition and modernity(modernity: 40-60% + tradition: 40-60%), 4 points were given to principal tradition + auxiliary modernity(modernity: 10-30% + tradition: 70-90%), and 5 points were given to principal tradition(modernity: 0-10% + tradition: 90-100%). The analysis performed according to those criteria and methodologies led to the following findings and conclusions: TM style, in which modernity was principal, usually did transformation and reinterpretation of traditionality. As for the design attributes of the styles, the TM style, they processed a majority of the spatial components as modern or reinterpretation of traditionality, which would be easily considered to be modern without careful observation, and applied a small amount of direct reproduction or transformation, which gives out a direct hint at traditionality, to attract more attention. Many of the spatial components did not express traditionality directly, expressing it indirectly or metaphorically. Traditionality was expressed in a small number of the spatial components, thus serving as a focus or impact point in the given space.

• Design Convergence Study
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• v.14 no.2
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• pp.17-32
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• 2015

The perspectives of customers and providers as for the services have the same objective; however, perspectives and objective are distinctly different. But the existing methodologies have mostly pondered only based on the customer-centric perspective or separately from the perspective of providers. It would be necessary to take these two perspectives as a whole by combining them into one perspective since they not only have differences but also common points. Therefore, in this study suggested the System Journey Map in terms of internal staff based on the customer's task in service. System Journey Map is consists of four parts : a customer journey map, thus the performance of internal staff, internal staff satisfaction evaluation, and finally the performance of internal staff assessment of the senior staff. After releasing a service, with customers and internal staff made a point of contact to identify specific behavioral patterns and whether any part of the problem so that this toolkit gives us an expectation to be a useful map, which is the intangible being placed in service, not just visualize and understand for identifying problems.

• Land and Housing Review
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• v.15 no.1
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• pp.157-165
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• 2024

As major public owner agencies in Korea have improved the application level of BIM, many design and construction companies are paying more attention to ways to improve actual work productivity in the BIM execution process. In this study, we introduce a method to automate the placement of BIM libraries, a recurring task in the BIM-based design process that serves as a prime example of BIM design automation methodologies. In particular, we classify the target surfaces for placement of BIM libraries into straight lines, curves, vertical planes, and surfaces. For each target surface, we implement a BIM library automatic placement model in Dynamo, considering the spacing and alignment according to the distance between the centers of two objects and the linear length. The results of case studies confirm that the proposed method can be employed according to various placement environments and conditions with the working time shortened. The study proposes that various objects and structures that need to be placed according to the terrain characteristics can be placed accurately, and work productivity can be significantly improved through the automation of placement.

• Journal of the Korean Society for information Management
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• v.41 no.3
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• pp.109-144
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• 2024

International research has actively explored and analyzed the implementation of e-learning platforms by libraries in response to the advancement of online learning models. In contrast, within Korea, while the significance and necessity of online library services and education are acknowledged, there remains a paucity of studies providing detailed methodologies for their implementation. This study aims to propose a practical e-learning platform for public libraries, detailing design guidelines and developing a prototype. Utilizing the Rapid Prototyping methodology, this study reviewed theoretical backgrounds and prior research, selecting Moodle LMS for initial design guidelines. The validity and reliability of the evaluation were assessed by experts and users. Based on the evaluation results, the final design guidelines and prototype of the e-learning platform for libraries were established. The final guidelines consist of four main functions, nine detailed functions, and forty specific instructions.

• Korean Journal of Construction Engineering and Management
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• v.8 no.4
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• pp.110-118
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• 2007

For deciding the owner's budget of the building construction in the predesign stage, the probabilistic methodologies for estimating the cost are often studied, however these parameter-based conceptual estimating methodology has limitation of applying it to the practical business because it hardly can link the design decision-making and the cost estimating and control. Besides if the result of detail estimating after detail design is over the budget, locally and arbitrarily control the level of interior design and fix the design. This research proposed the prototype-based cost estimating model for building interior construction which leads to estimate the interior cost easily linking with design decision-making and supports to evaluate the design alternatives in the schematic design and the design development stage for office buildings. The model divides the building on the design process by Element Breakdown Structure and presents the design alternative by selecting the elements of each room from the database accumulated the historical office buildings' prototypes and estimates the cost. The 2 case studies presented to validate the effectiveness of as the linking tool integrating the design and construction data and applicability to the practical design on the presented prototype-based model.