• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.496-499
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• 2015

The objective of the study is to develop selfie sticks to enhance portability and prevent error of pushing mobile phone button. The main target of selfie sticks is women and the size of selfie sticks is too big to put it in their bag. Also when people put mobile phone in a selfie stick, people push its button easily. Sometimes mobile phone is turned off or the volume is controlled because of pushing its button. The researcher focused on designing a solution that enhances portability and preventing error of pushing the button. The researcher understood structure of selfie stick. It consists of a mobile phone supporter and a length adjuster. The researcher designed the mobile phone supporter for enhancing portability and the length adjuster for preventing to push the mobile phone. The researcher designed a part which connects a mobile phone supporter with a length adjuster and made selfie stick fold. Also, sponges are partly put on the mobile supporter. It can reduce situation of pushing the mobile phone button. The selfie stick design from the study has an opportunity to distinguish using the product and carrying it and have people use the selfie stick conveniently.

• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.541-542
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• 2015

Recently, a popularity of the smartphone is on the rise. And also related services are being created. The growth of the smart technology makes advanced equipment for smartphone accessories. Selfie-rod is one of them. Selfie-rod satisfies people who want to take their own picture at long distance. However, the weight of recent selfie-rods is too heavy that has nice functions. So, we have re-designed new selfie-rod that has light-weight body. First, we observed a selfie-rod and check the reason of the selfie-rod's high weight. The new selfie-rod has a shell and inside, there is a space that it can be light-weight. The shell and space make the selfie-rod lighter. In FreeCAD, we designed shell with a rotation function. Finally, we designed light-weight body selfie-rod with FreeCAD. FreeCAD can be used easily for beginners of CAD. FreeCAD is suitable 3D-design tool for era of 3D-printing.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제38권2호
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• pp.110-115
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• 2012

Ankylosed tooth is defined as 'the discontinuance of normal passive tooth eruption without any mechanical barrier'. Ankylosed tooth treatment is a challenge to dental clinicians. In treatment of maxillary molar ankylosis cases there are risks of oro-antral fistula, displacement of root fragments into the maxillary sinus, as well as the necessity for providing additional sinus bone augmentation for future implant placement. In this study, we suggested a new technique using a piezoelectric device and a lateral side approach to the maxillary sinus leading to the simultaneous removal of the ankylosed maxillary molar and sinus grafting for the purpose of implant site development.

• Wind and Structures
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• 제14권1호
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• pp.35-53
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• 2011

Spherical object in wind is a common scenario in daily life and engineering practice. The main challenge in understanding the aerodynamics in turbulent wind lies in the multi-aspect of turbulence. This paper presents a wind tunnel study, which focuses on the role of turbulence integral length scale ${\Lambda}$ on the drag of a sphere. Particular turbulent flow conditions were achieved via the proper combination of wind speed, orifice perforated plate, sphere diameter (D) and distance downstream from the plate. The drag was measured in turbulent flow with $2.2{\times}10^4{\leq}Re{\leq}8{\times}10^4$, $0.043{\leq}{\Lambda}/D{\leq}3.24$, and turbulence intensity Tu up to 6.3%. Our results confirmed the general trends of decreasing drag coefficient and critical Reynolds number with increasing turbulence intensity. More interestingly, the unique role of the relative integral length scale has been revealed. Over the range of conditions studied, an integral length of approximately 65% the sphere diameter is most effective in reducing the drag.

• 대한산업공학회지
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• 제42권4호
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• pp.263-269
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• 2016

The purpose of this study is to challenge a computational regression-type problem, that is handling large-size data, in which conventional metamodeling techniques often fail in a practical sense. To solve such problems, regression-type boosting, one of ensemble model techniques, together with bootstrapping-based re-sampling is a reasonable choice. This study suggests weight updates by the amount of the residual itself and a new error decision criterion which constructs an ensemble model of models selectively chosen by rejection limits. Through these ideas, we propose AdaBoost.RMU.R as a metamodeling technique suitable for handling large-size data. To assess the performance of the proposed method in comparison to some existing methods, we used 6 mathematical problems. For each problem, we computed the average and the standard deviation of residuals between real response values and predicted response values. Results revealed that the average and the standard deviation of AdaBoost.RMU.R were improved than those of other algorithms.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권6호
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• pp.376-385
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• 2001

Considerable attention has been focused in recent years upon the field of biosorption for the removal of metal ions from aqeous effluents. Compared to other technologies, the advan-tages of biosortption are the high purity of the treated waste water and the cheap raw material. Really, the first major challenge for the biosorption field is to select the most promising types of biomass. Abundant biomass types either generated as a waste by-product of large-scale industrial fermentations particularly fungi or certain metal-binding seaweeds have gained importance in re-cent years due to their natural occurrence, low cost and, of course good performance in metal biosorption. Industrial solutions commonly contain multimetal systems or several organic and in organic substances that form complexes with metals at relatively high stability forming a very complex environment. When several components are present, interference and competition phe-nomena for sorption sites occur and lead to a more complex mathematical formulation of the process. The most optimal configuration for continuous flow-biosorption seems to the packed-bed column which gets gradually from the feed to the solution exit end. Owing to the com-petitive ion exchange taking place in the column, one or more of the metals present even at trace levels may overshot the acceptable limit in the column effluent before the breakthrough point of the trargeted metal. Occurrence of 'overshoot's and impact on havey metal removal has not been analyzed enough. New trends in biosorption are discussed in this review.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2018년도 학술발표회
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• pp.153-153
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• 2018

Water-Energy-Food (WEF) nexus is a new holistic resources management concept that considers the interconnections among resources for sustainable resources planning and management. The current challenge is to fulfill the required demand in the lack of available resources. A traditional way to provide more available resource is by increase in production, but it caused increment of indirect demand of other interlinked resources. Importing resources from other area (where local supply is redundant) is another option to secure local resources with additional economic expenditure. The WEF nexus-trading model adapts the previously developed nationwide nexus simulation model with additional input parameters and functions to simulate trading scenarios. In general, the analysis starts with the quantification of local resources deficit (potential importing amount) and redundancy (potential exporting amount) of each area. Then, a trade module is initiated by determining possible donor area and importation amount. Finally, the nexus simulation for all area is re-run to determine final resources supply-demand results including the trading amount. The trade option provides an opportunity to meet local demands without draining local resources. However, the production capability of donor area may limit the importation amount. The newly developed trade option allows more alternatives for stakeholders to determine resources management plans.

• 대한상부위장관⦁헬리코박터학회지
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• 제18권4호
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• pp.231-234
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• 2018

Peptic ulcer bleeding (PUB) is the most common cause of non-variceal upper gastrointestinal bleeding, and its frequency has been declining over the past decades. However, mortality from PUB persists, and it is still a serious challenge in clinical practice. Although endoscopic intervention is the basic treatment modality for PUB, pharmacological therapy is an important adjunct. The emergence of proton pump inhibitors (PPIs) enables maintenance of intragastric pH >6, which greatly helps in the treatment of PUB. Continuous intravenous infusion of high-dose PPI reduces the re-bleeding rate, thereby helping avoid additional surgery in patients with high-risk stigmata. Moreover, administration of PPIs prior to endoscopy may reduce the need for additional endoscopic intervention. Recently introduced gastric acid suppressants, such as potassium-competitive acid blockers, have shown promising results in further treatment of PUB.

• 멤브레인
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• 제29권4호
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• pp.191-201
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• 2019

산업 응용에 적용할 수 있는 중합체 막의 상용화 전에, 고성능 중합체가 실질적인 도전, 즉 연장된 서비스 시간에 대한 장기 안정성을 극복해야하는 과제가 남아있다. 매우 높은 분수 자유 부피(fractional free volume) 및 높은 투과성을 나타내는 고유한 미세 다공성 중합체(polymers of intrinsic microporosity)는 비효율적 무작위 패킹에 의해 생성된 여분의 부피가 물질의 부피적 평형에서 멀어짐과 동시에, 다시 부피적 평형 상태로 복귀하려는 특성, 즉 자유 부피를 줄여가는 특정으로 인해 투과성을 감소시키는 물리적 노화에 영향을 받기 쉽다. 본 논문에서 우리는 미세 다공성 고분자의 물리적 노화를 재검토하고 PIM에서 물리적 노화를 완화하려는 가장 두드러진 시도 중 일부를 논의할 것이다.

• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3567-3579
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• 2022

This paper provides an assessment of fluid transport and mixing processes inside the primary circuit of the test facility ROCOM through the numerical simulation of Test 2.1 with the system code ATHLET. The experiment represents an asymmetric injection of cold and non-borated water into the reactor coolant system (RCS) of a pressurized water reactor (PWR) to restore core cooling, an emergency procedure which may subsequently trigger a core re-criticality. The injection takes place at low velocity under single-phase subcooled conditions and presents a major challenge for the simulation in lumped parameter codes, due to multidimensional effects in horizontal piping and vessel arising from density gradients and gravity forces. Aiming at further validating ATHLET 3-D capabilities against horizontal geometries, the experiment conditions are applied to a ROCOM model, which includes a newly developed horizontal pipe object to enhance code prediction inside coolant loops. The obtained results show code strong simulation capabilities to represent multidimensional flows. Enhanced prediction is observed at the vessel inlet compared to traditional 1-D approach, whereas mixing overprediction from the descending denser plume is observed at the upper-half downcomer region, which leads to eventual deviations at the core inlet.