• Journal of Integrative Natural Science
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• v.10 no.2
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• pp.65-73
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• 2017

In this review paper, we will discuss about the methods of synthesizing Si nanowires by Top-down and Bottom-up. Silicon nanowires have a lot of application on various fields such as Li ion batteries, solar cells, chemical and biological sensors. We will address some of the applications of silicon Nanowires.

• Carbon letters
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• v.25
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• pp.89-94
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• 2018

In this study, we tried to prepare an isotropic spinnable pitch which can be useful to prepare the general purpose carbon fiber through the co-carbonization of biomass tar with ethylene bottom oil under two different preparation methods (atmospheric distillation, pressurized distillation). The results showed that the ethylene bottom oil added co-carbonization was very effective to decrease of the oxygen contents for obtaining a stable spinnable pitch. The pressurized distillation was more effective to reduce the oxygen functional groups of pitches than atmospheric distillation. The obtained spinnable pitch by the pressurized distillation showed higher pitch yield of 42% and lower oxygen content of 9.12% than the spinnable pitch by the atmospheric distillation. The carbon fiber derived from the pressurized distillation spinnable pitch by carbonization at $800^{\circ}C$ for 5 min showed that the higher tensile strength of carbon fiber was increased up to 800 MPa.

• 한국사회정책
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• v.20 no.3
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• pp.9-46
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• 2013

The degree of delegation related to the social security acts is involved in the candidate selection methods and the standing committee system. The social security acts with a small amount of delegation have an affinity with the bottom-up selection methods and the standing committee to guarantee long term in office. In Germany, the bottom-up selection method which guarantees the right of party members to nominate candidates and the standing committee to guarantee long term in office have an affinity with the Social Acts with less delegation. But the social security acts with a large number of delegation have an affinity with the top-down selection methods and the standing committee not to guarantee long term in office. In Korea, the top-down selection method in which the central headquarter of the party dominates the selection process, and the standing committee whose members are to be selected every two years have an affinity with the Social Security Acts with the excessive delegation.

• Journal of Broadcast Engineering
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• v.25 no.5
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• pp.750-757
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• 2020

One of the basic tasks for robots to interact with humans is to quickly and accurately grasp human behavior. Therefore, it is necessary to increase the accuracy of human pose recognition when the robot is estimating the human pose and to recognize it as quickly as possible. However, when the human pose is estimated using deep learning, which is a representative method of artificial intelligence technology, recognition accuracy and speed are not satisfied at the same time. Therefore, it is common to select one of a top-down method that has high inference accuracy or a bottom-up method that has high processing speed. In this paper, we propose two methods that complement the disadvantages while including both the advantages of the two methods mentioned above. The first is to perform parallel inference on the server using multi GPU, and the second is to mix bottom-up and One-class Classification. As a result of the experiment, both of the methods presented in this paper showed improvement in speed. If these two methods are applied to the entertainment robot, it is expected that a highly reliable interaction with the audience can be performed.

• Archives of Craniofacial Surgery
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• v.23 no.6
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• pp.256-261
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• 2022

Background: Treating panfacial fractures (PFFs) can be extremely difficult even for experienced surgeons. Although several authors have attempted to systemize the surgical approach, performing surgery by applying a unidirectional sequence is much more difficult in practice. The purpose of this study was to review the literature on PFF surgery sequence and to understand how different surgical specialists-plastic reconstructive surgery (PRS) and oral maxillofacial surgery (OMS)-chose sequence and review PFFs fixation sequence in clinical cases. Methods: The PubMed and Google Scholar databases were scoured for publications published up until May 2020. Data extracted from the studies using standard templates included fracture part, fixation sequence, originating specialist, and the countries. Bibliographic details like author and year of publication were also extracted. Also, we reviewed the data for PFFs patients in the Trauma Registry System of Dankook University Hospital from 2011 to 2021. Results: In total, 240 articles were identified. This study comprised 22 studies after screening and full-text analysis. Sixteen studies (12 OMS specialists and 4 PRS specialists) used a "bottom-top" approach, whereas three studies (1 OMS specialist and 2 PRS specialists) used a "top-bottom" method. However, three studies (only OMS specialists) reported on both sequences. In our hospital, there were a total of 124 patients with PFF who were treated during 2011 to 2021; 64 (51.6%) were in upper-middle parts, 52 (41.9%) were in mid-lower parts, and eight (6.5%) were in three parts. Conclusion: Bottom-top sequencing was mainly used in OMS specialists, and top-bottom sequencing was used at a similar rate by two specialists in literature review. In our experience, however, it was hard to consistently implement unidirectional sequence suggested by a literature review. We realigned the reliable and stable buttresses first with tailoring individually for each patient, rather than proceeding in the unidirectional sequence like bottom-top or top-bottom.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.175-177
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• 2020

In multi-channel wireless sensor networks, optimizing data aggregation delay without any channels and timeslots conflicts has been concerned these days. The aggregation delay can be reduced by using different aggregation tree construction methods or scheduling in different methods in bottom-up or top-down manners. In this paper, we propose a new way of constructing aggregation tree purposing to decrease the total aggregation delay. The result shows that our proposed scheme can improve up to 64% comparing with state-of-the-art schemes.

• Journal of Powder Materials
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• v.14 no.1 s.60
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• pp.26-31
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• 2007

Manufacturing bulk nanostructured materials with least grain growth from initial powders is challenging because of the bottle neck of bottom-up methods using the conventional powder metallurgy of compaction and sintering. In this study, bottom-up type powder metallurgy processing and top-down type SPD (Severe Plastic Deformation) approaches were combined in order to achieve both real density and grain refinement of metallic powders. ECAP (Equal Channel Angular Pressing), one of the most promising processes in SPD, was used for the powder consolidation method. For understanding the ECAP process, investigating the powder density as well as internal stress, strain distribution is crucial. We investigated the consolidation and plastic deformation of the metallic powders during ECAP using the finite element simulations. Almost independent behavior of powder densification in the entry channel and shear deformation in the main deformation zone was found by the finite element method. Effects of processing parameters on densification and density distributions were investigated.

• Journal of Biosystems Engineering
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• v.37 no.6
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• pp.359-364
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• 2012

Purpose: This study was conducted to analyze the vibration absorption effect for the agricultural product transportation-trailer equipped with vibration absorbable connecting hitch, leaf spring suspension, and shock absorber simultaneously (HLS), comparing with the trailer equipped with vibration absorbable connecting hitch only(H), trailer equipped with connecting hitch and leaf spring suspension (HL), and existing trailer with no vibration absorption device (E). Methods: Vertical accelerations were measured at driver seat and front, middle, rear parts of trailer bottom with no load for 4 types of transportation-trailer, and analyzed using FFT analyzer. Results: The magnitude of average vibration accelerations occurred up to 20 Hz, at this low frequencies the severe damage for agricultural products could be represented, was lower (maximum 6 times) for HLS trailer compared with H trailer. And vibration absorption effect for HLS trailer was also higher up to 40-80 Hz and 80-100 Hz, but the difference was less. At driver seat, the vibration absorption effect was high severely for HL and HLS trailer, and the magnitude of vibration acceleration was showed less difference in comparing at trailer bottom. Conclusions: From the test results, it could be recommended that the agricultural products transportation trailer should be equipped with vibration absorption device of HLS.

• Journal of KIISE:Databases
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• v.28 no.4
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• pp.606-619
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• 2001

This paper presents an efficient algorithm to compute difference between old and new versions of an SGML/XML document. The difference between the two versions can be considered to be an edit script that transforms some document tree into another The proposed algorithm is based on hybridization of bottom-up and top-down methods: matching relationships between nodes in the two versions are producted in a bottom-up manner and top-down breadth -first search computes an edit script. Because the algorithm does not need to investigate possible existence of matchings for all nodes, faster matching can be achieved . Furthermore, it can detect more structurally meaningful changes such as subtree move and copy as well as simple changes to the node itself like insert, delete, and update.

• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.793-803
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• 2021

The small PWR has been paid more and more attention due to its diversity of application and flexibility in the site selection. However, the large core power density, the small containment space and the rapid accident progress characteristics make it difficult to control the containment pressure like the traditional PWR during the LOCA. The pressure suppression system has been used by the BWR since the early design, which is a suitable technique that can be applied to the small PWR. Since the configuration and operating conditions are different from the BWR, the pressure suppression system should be redesigned for the small PWR. Conducting the experiments on the scale down test facility is a good choice to reproduce the prototypical phenomena in the test facility, which is both economical and reasonable. A systematic scaling method referring to the H2TS method was proposed to determine the geometrical and thermohydraulic parameters of the pressure suppression containment response test facility for the small PWR conceptual design. The containment and the pressure suppression system related thermohydraulic phenomena were analyzed with top-down and bottom-up scaling methods. A set of the scaling criteria were obtained, through which the main parameters of the test facility can be determined.