• Title/Summary/Keyword: M2M platform

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A Study on the Slowly Varying Wave Drift Force Acting on a Semi-Submersible Platform in Waves (반잠수식 시추선에 작용하는 장주기 표류력에 관한 연구)

  • S.Y.,Hong;P.M.,Lee;D.C.,Hong
    • Bulletin of the Society of Naval Architects of Korea
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    • v.26 no.2
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    • pp.49-63
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    • 1989
  • Wave drift forces which are small in magnitudes compared to the first order wave exciting forces can cause very large motion of a vessel in waves. In this paper a theoretical and experimental analysis is made of the mean and slowly varying wave dirft forces on the semi-submersible platform. Theoretical calculations are performed by using near field method with three dimensional diffraction theory and model tests are carried out in regular and irregular waves with a 1/60 semi model. Test results are compared with theoretical calculations and the mooring spring effects in the test are discussed.

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단일 나노선의 열전물성 측정용 열전 MEMS 플랫폼 개발

  • Sin, Ho-Seon;Jeon, Seong-Gi;Lee, U;Yu, Jin;Song, Jae-Yong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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    • pp.589-589
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    • 2013
  • 열전재료는 제백효과(Seebeck effect)에 의해 폐열을 전기에너지로 변환시킬 수 있는 소재로서, 기존의 열전재료가 나노수준으로 크기가 줄어들 경우 양자제한효과에 의한 제백계수의 증가와 표면산란에 의한 열전도도 감소로 인해 벌크재료에 비해 높은 에너지변환효율을 가질 수 있을 것으로 기대되고 있다. 에너지 변환효율은 열전성능계수인 ZT=S2σT/k로 정의되며 따라서 우수한 열전재료는 높은 제백계수 S와, 높은 전기전도도 σ 및 낮은 열전도도 k를 갖는 재료여야 한다. 그러나 나노소재는 낮은 측정 신호와 측정소자준비가 어려워 기존 측정시스템으로는 원활한 측정이 어렵다. 특히 열전도도의 경우 나노소재 자체의 열전도 보다 나노소재 주변 구조에 의한 열전도가 큰 경우 정확한 열전도도 평가가 어렵다. 본 연구에서는 나노선의 열전물성을 평가하기 위해 MEMS기반 기술을 이용하여 열전물성 측정플랫폼(MEMS-based thermoelectric measurement platform, MTMP)을 개발하였다. 개발 된 MTMP는 얇은 Si nitride 브릿지들이 허공에 떠 있는 두 개의 아일랜드 형태의 멤브레인 구조를 지지하는 형태로 제작되었으며, 한 쪽 아일랜드구조 위에는 나노히터가 있어 두 아일랜드 구조 사이에 온도구배를 만들 수 있도록 제작되었다. 제작된 멤브레인을 이용하여 전기화학적인 방법으로 합성한 Bi-Te계 나노선의 S, σ 그리고 k를 측정하였다. 측정결과 화학양론적 미세구조를 갖는 단결정 Bi2Te3 나노선은 300 K의 측정온도에서 $S=-57{\mu}V/K$, σ=3.9×105S/m, k=2.0 W/m-K의 측정 값으로 ZT=0.19였다. 본 연구에서 개발한 MTMP는 나노선 뿐만 아니라 나노플레이트의 열전 측정에도 활용할 수 있는 구조로서 나노열전소재 측정에 널리 활용될 수 있다.

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Elucidation of the Inhibitory Mechanisms of Nipponoparmelia laevior Lichen Extract against Influenza A (H1N1) Virus through Proteomic Analyses

  • Cuong, Tran Van;Cho, Se-Young;Kwon, Joseph;Kim, Duwoon
    • Journal of Microbiology and Biotechnology
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    • v.29 no.7
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    • pp.1155-1164
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    • 2019
  • Lichens contain diverse bioactive secondary metabolites with various chemical and biological properties, which have been widely studied. However, details of the inhibitory mechanisms of their secondary metabolites against influenza A virus (IAV) have not been documented. Here, we investigated the antiviral effect of lichen extracts, obtained from South Korea, against IAV in MDCK cells. Of the lichens tested, Nipponoparmelia laevior (LC24) exhibited the most potent inhibitory effect against IAV infection. LC24 extract significantly increased cell viability, and reduced apoptosis in IAV-infected cells. The LC24 extract also markedly reduced (~ 3.2 log-fold) IAV mRNA expression after 48 h of infection. To understand the antiviral mechanism of LC24 against IAV, proteomic (UPLC-HDMSE) analysis was performed to compare proteome modulation in IAV-infected (V) vs. mock (M) and LC24+IAV (LCV) vs. V cells. Based on Ingenuity Pathway Analysis (IPA), LC24 inhibited IAV infection by modulating several antiviral-related genes and proteins (HSPA4, HSPA5, HSPA8, ANXA1, ANXA2, HIF1α, AKT1, MX1, HNRNPH1, HNRNPDL, PDIA3, and VCP) via different signaling pathways, including HIF1α signaling, unfolded protein response, and interferon signaling. These molecules were identified as the specific biomarkers for controlling IAV in vitro and further confirmation of their potential against IAV in vivo is required. Our findings provide a platform for further studies on the application of lichen extracts against IAV.

One-pot synthesis of highly fluorescent amino-functionalized graphene quantum dots for effective detection of copper ions

  • Tam, Tran Van;Choi, Won Mook
    • Current Applied Physics
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    • v.18 no.11
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    • pp.1255-1260
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    • 2018
  • In this work, a green and simple one-pot route was developed for the synthesis of highly fluorescent aminofunctionalized graphene quantum dots (a-GQDs) via hydrothermal process without any further modification or surface passivation. We synthesized the a-GQDs using glucose as the carbon source and ammonium as a functionalizing agent without the use of a strong acid, oxidant, or other toxic chemical reagent. The as-obtained aGQDs have a uniform size of 3-4 nm, high contents of amino groups, and show a bright green emission with high quantum yield of 32.8%. Furthermore, the a-GQDs show effective fluorescence quenching for Cu2+ ions which can serve as effective fluorescent probe for the detection of Cu2+. The fluorescent probe using the obtained aGQDs exhibits high sensitivity and selectivity toward Cu2+ with the limit of detection as low as 5.6 nM. The mechanism of the Cu2+ induced fluorescence quenching of a-GQDs can be attributed to the electron transfer by the formation of metal complex between Cu2+ and the amino groups on the surface of a-GQDs. These results suggest great potential for the simple and green synthesis of functionalized GQDs and a practical sensing platform for Cu2+ detection in environmental and biological applications.

New Trends and Challenges of Internet Marketing

  • Nosshi, Anthony;Saad, Aziza;Senousy, M. Badr
    • Asia pacific journal of information systems
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    • v.25 no.2
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    • pp.337-355
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    • 2015
  • The Internet has become one of the most important channels for people to communicate and for companies to implement their sales promotion activities, such as advertising. Marketing and advertising attempt to influence customers' attitude to persuade them to choose to buy the advertisers' products instead of the competitors'. With the different forms of online marketing, such as search engine marketing, email marketing, and mobile marketing, advertisers can find more effective strategies to attract the attention of more targeted audiences. With the emergence of the social web (web 2.0), a new platform was introduced called social networks. This paper presents the current work in internet marketing activities until web 2.0, and conducts a social network analysis to aid in data extraction. Marketing and advertising companies have understood the power of information for a very long time. The more knowledge these companies have on the demographics, consumer habits, and preferences of particular customer types, the more they can tailor their product offerings, and the more sales they can make. This paper aims to understand the internet marketing concepts as well as present challenges and work directions in internet marketing.

Differential Effects of Acute and Chronic Exercise on Autophagy-related Gene Expression in Drosophila melanogaster (일회성 및 만성적 유산소운동이 초파리의 자가포식 관련 유전자 발현에 미치는 영향)

  • Kim, Hee Yeon;Kim, Hye Jin;Hwang, Ji Sun;Lee, Won Jun
    • Journal of Life Science
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    • v.24 no.11
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    • pp.1180-1186
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    • 2014
  • Autophagy, the lysosomal degradation pathway, is an intracellular recycling system that is necessary for the metabolic benefits of exercise and for producing lasting beneficial effects of exercise in various diseases. However, the most recent studies have only examined the effect of a single bout of exercise or resistance exercise on autophagic responses. To determine the differential effects of acute and chronic exercise on the expression of autophagy-related genes in D. melanogaster, white-eyed mutant D. melanogaster were assigned randomly to four groups: control, acute exercise, 2 hr chronic exercise, and 3 hr chronic exercise. The flies were exercised using a mechanized platform known as the Power Tower. Our results revealed that a single bout of exercise resulted in increased mRNA levels of the Atg8a gene (~20%, p<0.05). However, Atg1 and Atg6 mRNA expression were not induced by acute exercise. Transcript levels of Atg6 (~29%, p<0.05) related to the nucleation of autophagosomes were significantly induced by 2 hr of chronic exercise. However, this chronic exercise was not enough to increase Atg1 and Atg8a mRNA expression. On the other hand, 3 hr of exercise for 7 days significantly increased Atg1, Atg6, and Atg8a gene expression-about 57%, 37%, and 71%, respectively (p<0.05). These results suggest that a single bout of exercise is not enough to induce full activation of selected autophagy-related genes in D. melanogaster. Our results demonstrated that chronic regular exercise induced autophagy-related gene expression, suggesting that chronic regular exercise training might be required to activate autophagic responses important for producing beneficial effects of exercise in various diseases.

Preliminary Evaluation of Handling Qualities of a SAR(Search & Rescue) Helicopter Simulator Based on ADS-33 Requirements (ADS-33 평가기준에 따른 소방헬기 비행시뮬레이터의 비행조종성 예비평가)

  • Yoon, Sugjoon;Kim, Donghyun;Seong, Eunhye;Park, Taejun;Hwang, Hoyon;Ahn, Jon;Lee, Junghoon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.44 no.9
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    • pp.796-805
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    • 2016
  • As a part of the first stage in the helicopter flight simulator development, this study numerically evaluates handling qualities of the dynamics model. The flight dynamics model was generated using public information for AS365 N2, the target aircraft of the simulator. The flight simulator is under development as a pilot training and research tool for firefighting missions. The assessment of the model intends to validate general characteristics and suitability before the model is enhanced with flight test data. The evaluation is based on the ADS-33E-PRF(Aeroautical Design Standard Performance Specification Handling Qualities Requirement) criteria, with consideration of category of the aircraft, missions, and environment. The numerical operations follow required or recommended procedures of flight test for compliance demonstration. Evaluation results are evaluated according to the rating specified in maneuverability ADS-33E-PRF. Results have identified to provide a satisfactory platform for flight dynamic model in the general helicopter simulator generated based on the RotorLibFDM, and can be used as a base for basic training and research.

Preparation of Electrochemically Stable and SERS Active Silica@Gold Microshell (전기화학 반응용 표면증강라만산란 활성 실리카@금 마이크로쉘의 제작)

  • Piao, Lilin;Lee, Jihye;Chung, Taek Dong
    • Journal of the Korean Electrochemical Society
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    • v.16 no.1
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    • pp.46-51
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    • 2013
  • In order to monitor in situ electrochemical reaction we prepared the gold microshells on silica microspheres of 2μm in diameter which were able to not only work as electrodes but also surface enhanced Raman scattering (SERS) active substrates. Previously reported gold microshell using polystyrene as core material have a few serious problems, mostly coming from solubility in organic solvent, nonuniform distribution in size and toxicity of the polystyrene. Here we prepared silica core-gold microshell to obtain a strong SERS active platform benefitting from the physicochemical stability, uniformity and non-toxicity of silica. Varying the concentration of 3-aminopropyl triethoxysilane (APTES), the surfaces of silica beads were modified and the optimal condition was determined to be 1% APTES that made the SERS activity of gold microshell strongest. The gold microshells as made were characterized by homemade Micro-Raman system spectrometer, Field-Emission Scanning Electron Microscope.

Analysis of Dynamic Positioning System Based on Self-Tuning Control (자기동조 제어기를 이용한 위치확보 시스템에 관한 연구)

  • Sang-M.,Lee;Pan-M.,Lee;Sa-Y.,Hong
    • Bulletin of the Society of Naval Architects of Korea
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    • v.26 no.2
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    • pp.32-40
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    • 1989
  • Dynamic ship positioning(DP) system is used to keep the position and heading of a ship, or a floating platform, above a pre-selected site on the seabed by using thrusters. This paper presents a control system based on filtering technique and optimal control theory. The planar motions of a vessel are assumed to consist of low frequency(LF) component and high frequency(HF) one. The former is mainly due to thrusters, current, wind and second order wave forces, while the latter is mainly due to first order oscillatory component of the wave force. Furthermore position measurement signals include the noise. By means of self-tuning filter and Kalman filter techniques, LF motion estimates and HF ones are seperately achieved from the position measurements of the vessel. The estimated LF motions are used as input to the feedback loops. The total thruster power is minimized using the Linear Quadratic Gaussian control theory. The performance of the vessel with the DP system is investigated by computer simulation.

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Proteomic Changes in Chick Brain Proteome Post Treatment with Lathyrus Sativus Neurotoxin, β-N-Oxalyl-L-α,β-Diaminopropionic Acid (L-ODAP): A Better Insight to Transient Neurolathyrism

  • Anil Kumar, D;Natarajan, Sumathi;Omar, Nabil A M Bin;Singh, Preeti;Bhimani, Rohan;Singh, Surya Satyanarayana
    • Toxicological Research
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    • v.34 no.3
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    • pp.267-279
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    • 2018
  • Neurolathyrism is a neurodegenerative disorder characterized by spastic paraplegia resulting from the excessive consumption of Lathyrus sativus (Grass pea). β-N-Oxalyl-L-α,β-diaminopropionic acid (L-ODAP) is the primary neurotoxic component in this pea. The present study attempted to evaluate the proteome-wide alterations in chick brain 2 hr and 4 hr post L-ODAP treatment. Proteomic analysis of chick brain homogenates revealed several proteins involved in cytoskeletal structure, signaling, cellular metabolism, free radical scavenging, oxidative stress and neurodegenerative disorders were initially up-regulated at 2 hr and later recovered to normal levels by 4 hr. Since L-ODAP mediated neurotoxicity is mainly by excitotoxicity and oxidative stress related dysfunctions, this study further evaluated the role of L-ODAP in apoptosis in vitro using human neuroblastoma cell line, IMR-32. The in vitro studies carried out at 200μM L-ODAP for 4 hr indicate minimal intracellular ROS generation and alteration of mitochondrial membrane potential though not leading to apoptotic cell death. L-ODAP at low concentrations can be explored as a stimulator of various reactive oxygen species (ROS) mediated cell signaling pathways not detrimental to cells. Insights from our study may provide a platform to explore the beneficial side of L-ODAP at lower concentrations. This study is of significance especially in view of the Government of India lifting the ban on cultivation of low toxin Lathyrus varieties and consumption of this lentil.