• International Journal of Air-Conditioning and Refrigeration
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• v.17 no.2
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• pp.68-73
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• 2009

In this paper, a numerical study has been carried out to investigate the influence of volute geometries on the performance of a sirocco fan. In order to achieve an optimum volute design and explain the interactions between the different geometric configurations in the volute system, three-dimensional computational fluid dynamics and the 'design of experiment' method have been applied. Several geometric parameters, such as the volute expansion angle, the cut-off position and the bell mouth shape, are employed to improve efficiency and performance. $2^k$ factorial designs were performed to screen the most influential parameters and interactions, and showed that the cut-off position and the bell mouth shape are the most significant parameters. The optimum design was selected as a result of the response surface methodology, and effects of these parameters and their interactions were presented. From the results of computational analyses and experimental data, the performance and efficiency of the sirocco fan were successfully improved. Also, detailed effects of geometric variables of the volute system on the fan performance were discussed.

• International Journal of Fluid Machinery and Systems
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• v.4 no.1
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• pp.14-24
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• 2011

In this paper, design optimization for mixed-flow pump impellers and diffusers has been studied using a commercial computational fluid dynamics (CFD) code and DOE (design of experiments). We also discussed how to improve the performance of the mixed-flow pump by designing the impeller and diffuser. Geometric design variables were defined by the vane plane development, which indicates the blade-angle distributions and length of the impeller and diffusers. The vane plane development was controlled using the blade-angle in a fixed meridional shape. First, the design optimization of the defined impeller geometric variables was achieved, and then the flow characteristics were analyzed in the point of incidence angle at the diffuser leading edge for the optimized impeller. Next, design optimizations of the defined diffuser shape variables were performed. The importance of the geometric design variables was analyzed using $2^k$ factorial designs, and the design optimization of the geometric variables was determined using the response surface method (RSM). The objective functions were defined as the total head and the total efficiency at the design flow rate. Based on the comparison of CFD results between the optimized pump and base design models, the reason for the performance improvement was discussed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.3
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• pp.197-206
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• 2011

This study was conducted to optimize processing of functional seasoning sauce for instant noodles (SSIN) using response surface methodology (RSM), and to compare the functional properties of commercial SSIN. Central composite designs were adopted in the SSIN processing for ingredient formula optimization. Concentrations of sea tangle ($X_1$), traditional soy sauce ($X_2$), yeast extract ($X_3$) and Ecklonia cava extract (ECE) ($X_4$) were chosen as independent variables. The dependent variables were glutamic acid content ($Y_1$), score of sensory evaluation ($Y_2$), and antioxidative activity ($Y_3$). We found the optimal conditions to be $X_1$=3.91%, $X_2$=20.57%, $X_3$=3.04% and $X_4$=3.78%. The predicted values of the multiple response optimal conditions were $Y_1$=124.0 mg/100 g, $Y_2$=7.6 and $Y_3$=1.95. The antioxidative activity (PF, PF=oil induction period with sauce/oil induction period with distilled water) and ACE inhibitory activity of ECE-added SSIN were 1.98 and 29.0%, respectively, which were significantly higher than those of commercial SSIN (1.09 and 4.4%, respectively).

• Journal of Biosystems Engineering
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• v.41 no.4
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• pp.373-388
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• 2016

Background: Recent inquiries into high-quality foods have discussed the importance of the functional aspects of foods, in addition to traditional quality indicators such as color, firmness, weight, trimming loss, respiration rate, texture, and soluble solid content. Recently, functional Chinese cabbage, which makes up a large portion of the vegetables consumed in Korea, has been identified as an anticancer treatment. However, the investigation of practical issues, such as the effects of storage conditions on quality indicators (including functional compounds), is still limited. Purpose: We reviewed various studies on variations in the quality indicators and functional compounds of Chinese cabbage in response to different storage environments, focusing on storage temperature and storage period. In particular, we emphasized the effect of storage temperature and storage period on glucosinolate (GSL) levels, in order to provide guidelines for optimizing storage environments to maximize GSLs. Additionally, we used response surface methodology to propose experimental designs for future studies exploring the optimal storage conditions for enhancing GSL contents. Review: Large variations in quality indicators were observed depending on the cultivar, the type of storage, the storage conditions, and the harvest time. In particular, GSL content varied with storage conditions, indicating that either low temperatures or adequate air composition by controlled atmospheric storage may preserve GSL levels, as well as prolonging shelf life. Even though genetic and biochemical approaches are preferred for developing functional Chinese cabbage, it is important to establish a practical method for preserving quality for marketability; a prospective study into optimal storage conditions for preserving functional compounds (which can be applied in farms), is required. This may be achievable with the comprehensive meta-analysis of currently published data introduced in this review, or by conducting newly designed experiments investigating the relationship between storage conditions and the levels of functional compounds.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.4
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• pp.302-309
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• 2002

In order to improve the success rate of implants, various implant designs have been developed. Although there have been enough efforts to handle the surface of the implant with careful choice of material and mechanics so that the bone and the implant can be tightly joined together, they have still failed to play the role of periodontal ligaments of the natural teeth in the past. The role of periodontal ligaments is very important since it can improve the initial stability of implant by absorbing the impacts. The purpose of this study is, thus, to test the possibility of alleviating the impact when the surface of the implant was coated with chitosan, a natural polymer, and making sure that the coated material stayed on. Then, the condition of newly developed bone formation and the degree of inflammation in response was closely observed in the surface level. In the main experiment, Chitosan coated implant ($3.3mm{\times}7mm$) was implanted on both the right and the left side of rabbit's femur. The animals were each sacrificed on the $1^{st}$, $2^{nd}$, $3^{rd}$, $7^{th}$, $14^{th}$, $21^{st}$ and 28th day. The process was observed under an light microscope after the Toluidin Blue staining. From the experiment, it was found that the chitosan was evenly distributed on the surface of the screws, and the implant was adjoined with adjacent bone. There was a sign of inflammation on the $3^{rd}$ day, but on the $14^{th}$ day, the formation of woven bone and newly formed bones were noticed. Also, chitosan filled the gap was formed between the implant and the newly formed bone. The implant, the chitosan and the newly formed bone were forming one unit as a result. Therefore, it was found that chitosan coated implant could absorbe the impact in the initial stage of implant.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.4697-4706
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• 2010

This paper suggested the optimal operating design method using simulation and ANP(Analytic Network Process) for mass-customization in the automotive component manufacturing industry. For this, first of all, we built the simulation model including various and complex factors in the field, and estimated the meta-model by RSM(Response Surface Method). Secondly using ANP, we calculated the weight of relative importance of evaluation factors gathered from decision makers. And then, we proposed the optimal operation designs by MOGA(Multi-Objective Genetic Algorithm), analyzed results of them. Moreover, by comparing the results with the consequences using AHP(Analytic Hierarchy Process), we showed its superiority of suggested method to the manner using AHP, because it reflects inner, outer dependency, and inter-relation among judgement factors. In conclusion, through this process, we can present the better way to serve mover effective, precise, and accurate information to decision makers when they build operation design for mass-customization system as automotive parts production system.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.696-700
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• 2009

In this paper, we present a framework which enables users to interact naturally with hand gestures on a digital table. In general tabletop applications, one gesture is mapped to one function or command. Therefore, users should know these relations, and make predefined gestures as input. In contrast, users can make input gesture without cognitive load in our system. Instead of burdening users, the system possesses knowledge about gesture interaction, and infers proactively users' gestures and intentions. When users make a gesture on the digital surface, the system begins to analyze the gestures and designs the response according to users' intention.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.822-829
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• 2016

Our aim was to optimize the production of cellulase-free thermoactive xylanase by Aureobasidium pullulans CBS 135684 with statistical methodology based on experimental designs. Among eleven variables, the nutrient sources that had significant effect on xylanase production were corncob, $(NH_4)_2SO_4$, xylose, $KH_2PO_4$ and tween 80, identified by the initial screening method of Plackett-Burman. The optimum concentrations of these five components were subsequently investigated using response surface methodology. The optimal concentrations ($g{\cdot}l^{-1}$) for maximum production of xylanase were corncob, 39.0; $(NH_4)_2SO_4$, 3.0; xylose, 1.8; $KH_2PO_4$ 1.4; and tween 80, 1.4, respectively. An improved xylanase yield of $8.74{\pm}0.84U{\cdot}ml^{-1}$ was obtained with optimized medium which is 2.1-fold higher production than previously obtained results ($4.10{\pm}0.10U{\cdot}ml^{-1}$) after 48 h of cultivation. In addition, the xylanase production under optimal condition reached $10.09{\pm}0.27U{\cdot}ml^{-1}$ after 72 h of cultivation.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.6
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• pp.602-609
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• 2008

STATEMENT OF PROBLEM: Loss of the marginal bone to the first thread have been accepted but continuous effort have been made to reduce this bone loss by varying implant design and surface texture. PURPOSE: This animal study has examined the histomorphometric variations between implants with micro-thread, micro-grooved and turned surfaced neck designs. MATERIAL AND METHODS: Four mongrel dogs have been used the premolars removed and left to heal for three months. One of each implant systems with turned neck, micro-thread and micro-grooved were placed according to the manufacturers’protocol and left submerged for 8 and 12 weeks. These were then harvested for histological examination. RESULTS: The histologically all samples were successfully ossointegrated and active bone remodelling adjacent to implants. With the micro-grooved implants 0.40 mm and 0.26 mm of the marginal bone level changes were observed at 8 and 12 weeks respectively. The micro-threaded implants had changes of 0.79 mm and 0.56 mm at 8 and 12 weeks respectably. The turned neck designed implants had marginal bone level changes of 1.61 mm and 1.63 mm in 8 and 12 weeks specimens. A complex soft tissue arrangement could be observed against micro-threaded and micro-grooved implant surfaces. CONCLUSION: Within the limitations of this study, it could be concluded that implants with micro-grooved had the least and the turned neck designed implants had the most changes in the marginal bone level. The textured implant surfaces affect soft tissue responses.

• Restorative Dentistry and Endodontics
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• v.36 no.1
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• pp.1-11
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• 2011

Introduction: The aim of this paper is to discuss the mechanical and geometric features of Nickel-titanium (NiTi) rotary files and its clinical effects. NiTi rotary files have been introduced to the markets with their own geometries and claims that they have better ability for the root canal shaping than their competitors. The contents of this paper include the (possible) interrelationship between the geometries of NiTi file (eg. tip, taper, helical angle, etc) and clinical performance of the files as follows; - Fracture modes of NiTi rotary files - Non-cutting guiding tip and glide path - Taper and clinical effects - Cross-sectional area and clinical effects - Heat treatments and surface characteristics - Screw-in effect and preservation of root dentin integrity - Designs for reducing screw-in effect Conclusions: Based on the reviewed contents, clinicians may have an advice to use various brands of NiTi rotary instruments regarding their advantages which would fit for clinical situation.