• Title/Summary/Keyword: μ-approach

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Robust Velocity Control for Inverter-Driven Hydraulic Elevators Using DGKF/μ Approach (DGKF/μ 기법을 이용한 인버터구동 유압 엘리베이터의 강인한 속도 제어)

  • 강기호;김경서
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.2
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    • pp.271-271
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    • 2000
  • Although inverter-driven hydraulic elevators(HEL's) have advantages over traditional valve-controlled HEL's energy efficiency and performance they need robustness in performance and stability to accomodate nonlinearities big parametric variations and resonances in mechanical-hydraulic inner system. In this paper a robust controller based on DGKF/μ mixed approach is applied to a HEL system with carring capacity of 24 persons for Incheon International Airport. The results of a test tower(T/T) has shown good ro-bustness in performance and stability of the proposed controller thereby proving a feasibility of this robust controller-based approach for other HEL problems.

Discovery of Epinastine-NSAID Hybrids as Potential Anti-inflammatory Agents: Synthesis and In Vitro Nitric Oxide Production Inhibitory Activity Study

  • Woo, Hyeong Ryeol;Damodar, Kongara;Lee, Yeontaek;Lim, Soon-sung;Jeon, Sung Ho;Lee, Jeong Tae
    • Journal of the Korean Chemical Society
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    • v.64 no.2
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    • pp.79-83
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    • 2020
  • A novel pharmacophore with epinastine (1) and NSAID moieties (2-5) was designed by molecular hybridization approach. The hybrid compounds 6-9 were synthesized by EDCI/HOBt or HATU-mediated coupling of 1 with salicylic acid (2), mefenamic acid (3), indomethacin (4) and naproxen (5), respectively, and were assessed for their inhibitory effect against NO production in LPS-induced RAW-264.7 macrophages in vitro. The Hybrids were found to exhibit significant NO production inhibitory effects with half-maximal inhibitory concentration (IC50) values ranging in between 15.96 ± 1.32 and 36.68 ± 2.53 μM and were non-cytotoxic to macrophages. Comparing the inhibition concentration (IC50), cytotoxicity concentration (CC50) and in vitro efficacy index (iEI), 6 (IC50 = 17.97 ± 1.92 μM; iEI = 11.13) and 9 (IC50 = 15.96 ± 1.32 μM; iEI = 12.53) were better suited than other hybrids as well as their parent compound. Our findings signify that hybrids 6 and 9 may serve as platforms for continued investigations for the development of more efficient anti-inflammatory agents.

Re-conceptualization of Business Model for Marketing Nowadays: Theory and Implications

  • FIRMAN, Ahmad;PUTRA, Aditya Halim Perdana Kusuma;MUSTAPA, Zainuddin;ILYAS, Gunawan Bata;KARIM, Kasnaeny
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.7
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    • pp.279-291
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    • 2020
  • This study aims to develop the concept of innovation models with the marketing channel construct approach, marketing innovation, product segmentation, and customer insight; as well as improvements to the theory of resource-based combined with the method of service-dominant logic. This study approach is based on quantitative descriptive conducted with three stages of testing scenarios. The first test is the mapping of the innovation model construct through testing the validity and reliability with the moderation of customer orientation variables. The second scenario examines the relationship of influence between the independent variables on the dependent variable of 29 hypothetical analysis equation modeling. The unit of analysis was conducted on 497 SMEs involved in the food and beverage sectors, with the criteria being SMEs must have a rating of 4-5 points on the Go-Food applications software. The results shown that: 1) the construct used to develop an innovative model both directly and via moderation is positive and significant; 2) Through a complicated relationship that involves all components of the variable, it outlines a positive and significant effect except for the path of analysis (μ5). The theoretical and managerial implications state that the service-dominant logic approach and resource-based view theory have extreme reliability and interrelations.

A linear program approach for a global optimization problem of optimizing a linear function over an efficient set (글로벌최적화 문제인 유효해집합 위에서의 최적화 문제에 대한 선형계획적 접근방법)

  • 송정환
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2000.04a
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    • pp.53-56
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    • 2000
  • The problem ( Ρ ) of optimizing a linear function d$\^$T/x over the set of efficient set for a multiple objective linear program ( Μ ) is difficult because the efficient set is nonconvex. There some interesting properties between the objective linear vector d and the matrix of multiple objectives C and those properties lead us to establish criteria to solve ( Ρ ) with a linear program. In this paper we investigate a system of the linear equations C$\^$T/${\alpha}$=d and construct two linearly independent positive vectors ${\mu}$, ν such that ${\alpha}$=${\mu}$-ν. From those vectors ${\mu}$, ν, solving an weighted sum linear program for finding an efficient extreme point for the ( Μ ) is a way to get an optimal solution ( Ρ ). Therefore our theory gives an easy way of solving nonconvex program ( Ρ ) with a weighted sum linear program.

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Diamond-like Carbon Tribological Endurance using an Energetic Approach

  • Alkelae, Fathia;Jun, Tea-Sung
    • Tribology and Lubricants
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    • v.37 no.5
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    • pp.179-188
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    • 2021
  • Reputed for their low friction coefficient and wear protection effect, diamond-like carbon (DLC) materials are considered amongst the most important lubricant coatings for tribological applications. In this framework, this investigation aims to elucidate the effect of a few operating parameters, such as applied stress and sliding amplitude on the friction lifetime of DLC coatings. Fretting wear tests are conducted using a 12.7 mm radius counterpart of 52100 steel balls slid against a substrate of the same material coated with a 2 ㎛ thickness DLC. Approximately, 5 to 57 N force is applied, generating a maximum Hertzian contact pressure of 430 to 662 MPa, corresponding to the applied force. The coefficient of friction (CoF) generates three regimes, first a running-in period regime, followed by a steady-state evolution regime, and finally a progressive increase of the CoF reaching the steel CoF value, as an indicator of reaching the substrate. To track the wear scenario, interrupted tests are performed with analysis combining scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), 3D profilometer and micro-Raman spectroscopy. The results show two endurance values: one characterizing the coating failure (Nc1), and the other (Nc2) indicating the friction failure which is situated where the CoF reaches a threshold value of μth = 0.3 in the third regime. The Archard energy density factor is used to determine the two endurance values (Nc1, Nc2). Based on this approach, a master curve is established delimitating both the coating and the friction endurances.

Wide Bandwidth GaAs FET Distributed Amplifier in Microwave Frequencies (GaAs FET 마이크로파 증폭기 (분배증폭기에서 대역폭을 증가시키는 방법을 중심으로))

  • 장익수
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.21 no.1
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    • pp.51-56
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    • 1984
  • This paper describes the analysis and design of a GaAs FET distributed amplifier connecting a series capacitor to get a super wide bandwidth by reducing the gate line attenuation constant. In this approach a design example with a 300$\mu$ gate length FET devices is presented, and the abtained results are; that without series capacitors the bandwidth is 2-12 GHz, but with capacitors 2-20 GHz in flat gain.

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Microfluidic Image Cytometry (μFIC) Assessments of Silver Nanoparticle Cytotoxicity

  • Park, Jonghoon;Yoon, Tae Hyun
    • Bulletin of the Korean Chemical Society
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    • v.33 no.12
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    • pp.4023-4027
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    • 2012
  • Cytotoxicity assessment of silver nanoparticles (AgNPs) was performed using MTT-based microfluidic image cytometry (${\mu}FIC$). The $LC_{50}$ value of HeLa cells exposed to AgNPs in the microfluidic device was estimated as 46.7 mg/L, which is similar to that estimated by MTT-based IC for cells cultured in a 96 well plate (49.9 mg/L). These results confirm that the ${\mu}FIC$ approach can produce cytotoxicity data that is reasonably well-matched with that of the conventional 96 well plate system with much higher efficiency. This ${\mu}FIC$ method provides many benefits including ease of use and low cost, and is a more rapid in vitro cell based assay for AgNPs. This may aid in speeding up data acquisition in the field of nanosafety and make a significant contribution to the quantitative understanding of nanoproperty-toxicity relationships.

Quantitative Polymerase Chain Reaction for Microbial Growth Kinetics of Mixed Culture System

  • Cotto, Ada;Looper, Jessica K.;Mota, Linda C.;Son, Ahjeong
    • Journal of Microbiology and Biotechnology
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    • v.25 no.11
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    • pp.1928-1935
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    • 2015
  • Microbial growth kinetics is often used to optimize environmental processes owing to its relation to the breakdown of substrate (contaminants). However, the quantification of bacterial populations in the environment is difficult owing to the challenges of monitoring a specific bacterial population within a diverse microbial community. Conventional methods are unable to detect and quantify the growth of individual strains separately in the mixed culture reactor. This work describes a novel quantitative PCR (qPCR)-based genomic approach to quantify each species in mixed culture and interpret its growth kinetics in the mixed system. Batch experiments were performed for both single and dual cultures of Pseudomonas putida and Escherichia coli K12 to obtain Monod kinetic parameters (μmax and Ks). The growth curves and kinetics obtained by conventional methods (i.e., dry weight measurement and absorbance reading) were compared with that obtained by qPCR assay. We anticipate that the adoption of this qPCR-based genomic assay can contribute significantly to traditional microbial kinetics, modeling practice, and the operation of bioreactors, where handling of complex mixed cultures is required.

The Effect of Microcurrent Stimulation on Pain and Quality of Life in Women with Primary Dysmenorrhea

  • Minkyoung Kwon;Wonjae Choi
    • Physical Therapy Rehabilitation Science
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    • v.12 no.3
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    • pp.293-299
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    • 2023
  • Objective: This study aimed to investigate the potential benefits of microcurrent stimulation as a non-invasive therapeutic approach for managing pain and improving the quality of life in women suffering from primary dysmenorrhea. Design: A case study. Methods: This study was conducted, involving a cohort of 6 women diagnosed with primary dysmenorrhea, aged between 20 to 30 years. Participants were received microcurrent stimulation using low-intensity microcurrents for 30 minutes every day for 4 weeks. The intensity of microcurrent stimulation was 25 μA and the frequency was 8 Hz. The intervention was administered between the menstruations, with pain intensity and quality of life being assessed at baseline, and then at the end of menstrual cycle. Pain intensity was evaluated using a visual analog scale (VAS) and menstrual symptom questionnaire (MSQ), while the quality of life was assessed through the stress response inventory (SRI), state trait anxiety inventory (STAI), center for epidemiologic studies depression (CES-D), and menstrual distress questionnaire (MEDI-Q). Results: After the intervention, participants demonstrated a statistically significant reduction in pain intensity, as evidenced by improved VAS scores (p<0.05). However, the changes in MSQ scores did not reach statistical significance. Regarding quality of life measures, no statistically significant differences were found in the SRI, STAI, CES-D, and MEDI-Q scores after the intervention (p>0.05). Conclusions: This study suggest that microcurrent stimulation holds promise as a potential treatment option for alleviating pain associated with primary dysmenorrhea.

FMN-Based Fluorescent Proteins as Heavy Metal Sensors Against Mercury Ions

  • Ravikumar, Yuvaraj;Nadarajan, Saravanan Prabhu;Lee, Chong-Soon;Jung, Seunho;Bae, Dong-Ho;Yun, Hyungdon
    • Journal of Microbiology and Biotechnology
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    • v.26 no.3
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    • pp.530-539
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    • 2016
  • Bacterial light-oxygen-voltage-sensing photoreceptor-derived flavin mononucleotide (FMN)-based fluorescent proteins act as a promising distinct class of fluorescent proteins utilized for various biomedical and biotechnological applications. The key property of its independency towards oxygen for its chromophore maturation has greatly helped this protein to outperform the other fluorescent proteins such as GFP and DsRed for anaerobic applications. Here, we describe the feasibility of FMN-containing fluorescent protein FbFP as a metal-sensing probe by measuring the fluorescence emission changes of a protein with respect to the concentration of metal ions. In the present study, we demonstrated the mercury-sensing ability of FbFP protein and the possible amino acids responsible for metal binding. A ratiometric approach was employed here in order to exploit the fluorescence changes observed at two different emission maxima with respect to Hg2+ at micromolar concentration. The engineered variant FbFPC56I showed high sensitivity towards Hg2+ and followed a good linear relationship from 0.1 to 3 μM of Hg2+. Thus, further engineering with a rational approach would enable the FbFP to be developed as a novel and highly selective and sensitive biosensor for other toxic heavy metal ions as well.