• Journal of Environmental Science International
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• v.31 no.8
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• pp.691-706
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• 2022

Magnetic activated carbon was prepared by adding a magnetic material to activated carbon that had been prepared from waste citrus peel in Jeju. The adsorption characteristics of an aqueous solution of the antibiotic trimethoprim (TMP) were investigated using the magnetic activated carbon, as an adsorbent, and response surface methodology (RSM). Batch experiments were carried out according to a four-factor Box-Behnken experimental design affecting TMP adsorption with their input parameters (TMP concentration: 50~150 mg/L; pH: 4~10; temperature: 293~323 K; adsorbent dose: 0.05~0.15 g). The significance of the independent variables and their interaction was assessed by ANOVA and t-test statistical techniques. Statistical results showed that TMP concentration was the most effective parameter, compared with others. The adsorption process can be well described by the pseudo-second-order kinetic model. The experimental isotherm data followed the Langmuir isotherm model. The maximum adsorption capacities of TMP, estimated with the Langmuir isotherm model were 115.9-130.5 mg/g at 293-323 K. Also, both the thermodynamic parameters, ΔH and ΔG, have both positive values, indicating that the adsorption of TMP by the magnetic activated carbon is an endothermic reaction and proceeds via an involuntary process.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1797-1802
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• 2010

This paper proposes a new fuzzy speed controller based on the Takagi-Sugeno fuzzy method to achieve a robust speed control of a permanent magnet synchronous motor(PMSM). The proposed controller requires the information of the load torque, so the second-order load torque observer is used to estimate it. The LMI condition is derived for the existence of the proposed fuzzy speed controller, and the LMI parameterization to calculate the gain matrices of the controller is provided. It is proven that the augmented control system including the fuzzy speed controller and the load torque observer is exponentially stable. To evaluate the performance of the proposed fuzzy speed controller, the simulation and experimental results are presented under motor parameter and load torque variations. Finally, it is clearly verified that the proposed control method can be used to accurately control the speed of a permanent magnet synchronous motor.

• Transactions of Materials Processing
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• v.26 no.2
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• pp.79-86
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• 2017

In this study, the sheet metal forming process of the brake chamber head, which had a complex shape compared to the conventional head part, was investigated using finite element (FE) analysis. In order to prevent the forming failures such as necking and fracture, the multi-stage forming process was introduced. The forming process consisted of three steps: (1) first drawing, (2) second drawing, (3) final forming. Experimental and FE simulated results of the brake chamber head were compared, and the results showed that the required characteristics of the straightness and the wall thickness at each location were satisfied.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.5
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• pp.338-344
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• 2004

This paper presents a sensorless speed control of a DC servo motor using a fuzzy-sliding observer in the presences of load disturbances. A fuzzy-sliding observer is proposed in order to estimate the speed of a motor rotor. First, a sliding observer is used to estimate the derivative of the armature current directly using the armature current mesured in the DC servo motor. Second, the optimal gain of the Luenberger observer is set up using the fuzzy control. Experimental results show the good performance in the DC servo motor system with the proposed fuzzy-sliding observer.

• Journal of Korean Society for Quality Management
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• v.7 no.1
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• pp.3-14
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• 1979

The primary objective of this paper is to aid the scientists and engineers in applying response surface procedures to obtain optimum operating conditions for many technical fields, particularly, for industrial manufacturing process. When a set of data is available from an experimental design, it is often of interest to fit a second order polynomial regression model in k independent variables, and find the condition of the independent variables (e. g., temperature, pressure, etc.) that optimize the response variable (e. g., yield, strength, etc.). This paper proposes a method how to obtain the optimum operating condition, and how 10 find the condition by using the computer. A computer program written in FORTRAN language is attached for the readers who may want to use the computer program.

• 한국전산유체공학회:학술대회논문집
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• 2001.05a
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• pp.60-65
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• 2001

The projectile afterbodies for zero-lift drag reduction has been analyzed using the Navier-Stokes equations with the $\kappa-\epsilon$ turbulence model. The numerical method of a second order upwind scheme has been used on unstructured adaptive meshes. Base drag reduction methods that have been found effective on axisymmetric bodies include boattailing, base bleed, base comustion, locked vortex afterbodies and multistep afterbodies. In this paper, the charateristics of turbulence flow have been studied for geomeries of multistep afterbodies. The important geometrical and flow parameters relevant to the design of such afterbodies have been identified by number, length and height of step. The flow over multistep afterbodies has been analyzed including expansion waves, recompression waves, recirculating flow, shear flow and wake flow. The numerical results have been compared and analyzed with the experimental datum.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.102-107
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• 2004

New designed floating breakwater made of Polyethelener with considering the introduction of new material for being harmony with environment and stability of the floater is developed for a marine ranching. Model experiment in order to test its capability is performed for the regular and irregular waves in ocean engineering basin. Good capability to break the incident wave within the 6 second of period and 1 m of height is shown. Breaking efficiency for long period wave is not so good in regular and irregular wave. The results of this study will contribute to the design and construction of the floating breakwater.

• Korean Institute of Interior Design Journal
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• v.19 no.5
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• pp.226-233
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• 2010

This study is to analyze and determine the emotional design on domestic rec-education space, in order to propose a way to design children rec-education space. A study is on reviewing needs and verify categories of emotional design through interior design of rec-education space, A study procedure will begin with theoretical proofing of children rec-education and move on to needs of emotional design in interior design and types of analysis for it. With this procedure, we will project adequate way for emotional characteristics in rec-education space and will analyze types of it from interior design of rec-education space in nine different domestic brands. With this background, we like to present methods and reveal characteristics of it. The conclusion on this study is described as followed. First, children rec-education space has positively carried types of emotional characteristics: experimental, continuity, and symbolism. Second, Some precondition; application through types of pattern, experimentation on light in space, continuity on linear interior space composition, symbolism in abstract implementation, and physical control over designed subject, has low effectiveness on creating emotional space by applying such scale matters. Third, the actual interior design subject matters and supporting facilities' textural accommodation is inadequately built for their majority, children, whether it is direct or indirect for contact. Forth, Even though to carry emotional space needs some kinds of story telling and prerequisite sequential space composition, there are lack of applicable space compositions. For this reason, it needs on going study in emotional space for children rec-education space. Last, there are needs for researching a depth understanding and presenting different characteristics of emotional interior design by brands.

• The Research Journal of the Costume Culture
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• v.14 no.5
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• pp.813-827
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• 2006

In this investigation, the following study was carried out for an experimental proposal of the knit item lists which were not actualized due to lack of studies. First of all, we have put the knit item titles that have been used through the document investigation, into the lists in order to clarify the original item list. Furthermore, we have pointed out the problems and the areas to be developed in the original item lists, and proposed twenty new knit item lists. By defining the design traits of each item, we have established item list which could be classified more systematically. As a result, the knit item titles of twenty newly proposed item titles are knit pull over, knit pull over top, knit top, knit t shirt, knit shirt, knit polo shirt, knit blouse, knit vest, knit hood, knit jumper, knit jacket, knit coat, knit cardigan, knit ensemble, knit cape, knit shawl, knit bikini, knit one-piece, knit pants, and knit skirt. Secondly, in order to investigate the possibility of practical use of twenty knit item lists proposed by this study, we have applied anova with repeated measurement for foreign fashion collection knit item trends of the past 10 years based on the proposed item lists. As a result, four items classified as top, shirt, cardigan, and pants had similar changes in the trend for last 10 years in S/S season while eleven items classified as pull over, pull over top, blouse, vest, jacket, coat, cardigan, ensemble, cape, shawl, and one-piece had similar trend changes for F/W season. The first significance of this study is on the experimental proposal of knit item list which could be used in the actual clothing industry and academic field. Furthermore, by defining the design traits of each knit item, it sublated the confusions brought by vocabularies in design of knit products and distribution in the industry perspective, and it made it possible to categorize the knit items correctly in knit design analysis and knit design education in academic field. The second significance shows that this study brought about positive results in the possibility of industrial academic practical use of proposed list by indicating that most of the knit designs appeared in the foreign collections in the past ten years could be correctly classified through investigational analysis.

• Korean Institute of Interior Design Journal
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• v.21 no.3
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• pp.144-153
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• 2012

This study analyzed and investigated problems of local safety experience halls' spatial structure and media status. Improvements would be suggested after comprehending the need to execute safety education based on citizen's satisfaction and requests. Contents of safety experience space concept, display characteristics and types applied to local institution were analyzed. Safety experience centers with systemized protocols that opened after 2003 and were bigger than $5,000m^2$ were selected. We had three candidates and they were Seoul Gwangnaru Safety Experience Center, Boramea Safety Experience Center and Daegu Safety Theme Park. Going through checklists and interviewing official institutions that were in charge of safety hall educations helped comprehension of sample space status and detailed experimental presentation media. A survey was created based on this study and was distributed to users and non-users of safety experience halls. The survey consisted of general questions covering situations, awareness, level of interests, frequency and satisfaction level. The results were extracted with SPSS 18.0 through frequency analysis and cross tabulations. This research improvements through synthesized contemplation. For the resuits First, various experimental programs need to be supplemented in order to prevent accidents. Second, vivid experimental spaces need to be planned for active participation and users should be fully aware of safety hazard through education. Third, there weren't enough institutions compared to the education needs. Promoting and building more safety experience halls are dire. Finally, these suggestions of the results will be distributed in the planning of the exhibit hall.