• Title/Summary/Keyword: Capture Mechanism

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Design and test of cable based airborne capture mechanism for drone (케이블을 사용한 드론용 공중 포획 메커니즘의 설계 및 테스트)

  • Jung, Sanghoon;Nguyen, Van Sy;Kim, Byungkyu;An, Taeyoung
    • Journal of Aerospace System Engineering
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    • v.14 no.3
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    • pp.10-16
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    • 2020
  • We propose a capture mechanism based on the principles of fishing nets that can be mounted on the drone using cable. The gripper mechanism, mainly proposed for the drone is heavy, and is limited to catch standardized objects. In contrast, the proposed capture device in this paper is light, flexible, and can capture various types of objects from a long distance. The theoretical relationships between cables and mechanisms were analyzed. Finally, the capture device was designed and manufactured to be installed in the drone (DJI S900) to conduct capturing experiments for various objects and verify the validity.

Does the Pricing Mechanism Affect the IPO Flipping Activity in Pakistan?

  • ANWAR, Ayesha;MOHD-RASHID, Rasidah
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.1
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    • pp.237-246
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    • 2021
  • This paper explores the relationship between price mechanism and flipping activity of initial public offerings (IPOs) in Pakistan's emerging economy. This study uses a cross-sectional data set of 95 firms listed on Pakistan Stock Exchange from 2000 to 2019. This study employs the ordinary least square and quantile regression techniques to capture the relationship between price mechanism and flipping activity. The results show that book-built IPOs flip substantially less than fixed-price IPOs. This is consistent with the signaling theory assertion that roadshows are arranged by underwriters to capture investors' demand and set the offer prices of IPOs. If investors learn the fair values of quality IPOs, then the offer prices will be close to the intrinsic values, thus reducing flipping. The findings also provide conclusive evidence for understanding the usefulness of and the more relevant information regarding the pricing mechanism. In particular, it provides a better understanding of how companies actually use the pricing mechanism information in the flipping of IPO shares. The results of this study are also valuable to underwriters, and regulators, for instance, provides underwriters with the discretion to allocate the IPO shares and the SECP, in revising regulation on the disclosure of IPO pricing methods.

Investigation of Moving Angle of Power Take off Mechanism on the Efficiency of Wave Energy Converter (파력발전기의 동력인출장치의 회전각도가 효율에 미치는 영향 분석)

  • Do, H.T.;Nguyen, M.T.;Phan, C.B.;Lee, S.Y.;Park, H.G.;Ahn, K.K.
    • Journal of Drive and Control
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    • v.12 no.3
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    • pp.25-35
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    • 2015
  • The hydraulic power-take-off mechanism (HPTO) is one of the most popular methods in wave energy converters (WECs). However, the conventional HPTO with only one direction motion has a number of drawbacks that limit its power capture capability. This paper proposes an adjustable moving angle wave energy converter (AMAWEC) and investigates the effect of the moving angle on the performance of the wave energy converter to find the optimal moving angle in order to increase the power capture capability as well as energy efficiency. A mathematical model of components from a floating buoy to a hydraulic motor was modeled. A small scale WEC test rig was fabricated to verify the power capture capability and efficiency of the proposed system through experiments.

Absorption of SO2 at High Temperatures by Ionic Liquids and the Absorption Mechanism

  • Tian, Shidong;Hou, Yucui;Wu, Weize;Ren, Shuhang;Qian, Jianguo
    • Bulletin of the Korean Chemical Society
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    • v.35 no.9
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    • pp.2791-2796
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    • 2014
  • The capture of $SO_2$ at or close to the temperatures of real flue gas is much more attractive in application. In this work, two kinds of ionic liquids (ILs) based on lactate anion were used to absorb $SO_2$ at high temperatures from 100 to $120^{\circ}C$. The ILs show high absorption capacities of over one mol $SO_2$ per mol IL at $110^{\circ}C$. The absorption of $SO_2$ by the ILs based on lactate anion is reversible and the ILs can be reused for the capture of $SO_2$ at high temperatures with high absorption capacity and thermal stability. Furthermore, the absorption mechanism of $SO_2$ by the ILs was studied by FT-IR, $^1H$ NMR and $^{13}C$ NMR spectra. It has been found that there are strong chemical interactions between the ILs and $SO_2$. Also the absorption mechanism is different when there is water present in ILs compared to when there is not.

Ergonomics-based Design of 7 Degrees of Freedom Motion Capture Device (인간공학기반 7자유도 모션캡쳐 장치 설계)

  • Loh, Byoung Gook;Choi, Gi Heung
    • Journal of the Korean Society of Safety
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    • v.29 no.1
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    • pp.41-46
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    • 2014
  • The design of a 7 degree of freedom motion capture device(MCD) has been presented. The newly designed MCD overcomes the shortcomings of the existing CADEN-7 exoskeleton robot by implementing various ergonomic design. To improve ease of operation, light-weight high-strength materials such as carbon pipes and engineering plastics were used to reduce weight of the MCD and arm-length adjustment mechanism was also added. The MCD showed consistent measurement results in designed experiments involving change of arm posture from nominal configuration to either elbow-side or arm-front configurations. Furthermore, captured motion in more natural tennis swing appeared to agree well with visual observations made.

Implementation of Human Motion Following Robot through Wireless Communication Interface

  • Choi, Hyoukryeol;Jung, Kwangmok;Ryew, SungMoo;Kim, Hunmo;Jeon, Jaewook;Nam, Jaedo
    • 제어로봇시스템학회:학술대회논문집
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    • 2002.10a
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    • pp.36.3-36
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    • 2002
  • $\textbullet$ Motion capture system $\textbullet$ Exoskeleton mechanism $\textbullet$ Kinematics analysis $\textbullet$ Man-machine Interface $\textbullet$ Wireless communication $\textbullet$ Control algorithm

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Thermal Degradation of Aqueous MEA Solution for CO2 Absorption by Nuclear Magnetics Resonance (핵자기공명분석법을 이용한 수용성 아민 CO2 흡수제인 MEA의 열적변성 분석)

  • CHOI, JEONGHO;YOON, YEOIL;PARK, SUNGYOUL;BAEK, ILHYUN;KIM, YOUNGEUN;NAM, SUNGCHAN
    • Journal of Hydrogen and New Energy
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    • v.27 no.5
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    • pp.562-570
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    • 2016
  • At the carbon dioxide capture process using the aqueous amine solution, degradation of absorbents is main factor to reducing the process performance. Also, degradation mechanism of absorbent is important for understanding the environmental risk, route of degradation products, health risk etc. In this study, the degradation products of MEA were studied to clarify mechanism in thermal degradation process. The degradation products were analyzed using a $^1H$ NMR (nuclear magnetic resonance) and $^{13}C$ NMR. The analysis methods used in this study provide guidelines that could be used to develop a degradation inhibitor of absorbent and a corrosion inhibitor.

MSFM: Multi-view Semantic Feature Fusion Model for Chinese Named Entity Recognition

  • Liu, Jingxin;Cheng, Jieren;Peng, Xin;Zhao, Zeli;Tang, Xiangyan;Sheng, Victor S.
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.6
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    • pp.1833-1848
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    • 2022
  • Named entity recognition (NER) is an important basic task in the field of Natural Language Processing (NLP). Recently deep learning approaches by extracting word segmentation or character features have been proved to be effective for Chinese Named Entity Recognition (CNER). However, since this method of extracting features only focuses on extracting some of the features, it lacks textual information mining from multiple perspectives and dimensions, resulting in the model not being able to fully capture semantic features. To tackle this problem, we propose a novel Multi-view Semantic Feature Fusion Model (MSFM). The proposed model mainly consists of two core components, that is, Multi-view Semantic Feature Fusion Embedding Module (MFEM) and Multi-head Self-Attention Mechanism Module (MSAM). Specifically, the MFEM extracts character features, word boundary features, radical features, and pinyin features of Chinese characters. The acquired font shape, font sound, and font meaning features are fused to enhance the semantic information of Chinese characters with different granularities. Moreover, the MSAM is used to capture the dependencies between characters in a multi-dimensional subspace to better understand the semantic features of the context. Extensive experimental results on four benchmark datasets show that our method improves the overall performance of the CNER model.

A Linkage Based Space Debris Capture Device Utilizing Kevlar Wires (Kevlar wire를 이용한 링크 구동형 우주잔해 포획장치)

  • Jung, Jinwon;Hwang, Bohyun;Kim, Heekyung;Lee, Gunhee;Seo, Minseok;Lee, Dongyun;Kim, Byungkyu
    • Journal of Aerospace System Engineering
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    • v.11 no.5
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    • pp.36-41
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    • 2017
  • As the space debris in the satellite orbit increases, the risk of collision between the currently operating satellites and the space debris is continuously increasing. Therefore, in this study, we designed one-degree-of-freedom capture device using simple deployment mechanism. The capture device consists of four link groups connected with net. To increase the reliability, each link group is connected to one driving part so that the total degree of freedom is 1. In addition, the links were stowed on each side of the satellites so that they would not affect the janitor satellite mission. Finally, to confirm the possibility of deployment in the space environment, we carried out deployment experiments in water similar to the microgravity environment, and confirmed the deployment of capture device and the possibility of capturing target satellite.