• Title/Summary/Keyword: Current derivative

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The Supply and Demand Projection of Nurses in Korea (간호사인력의 수요와 공급 추계)

  • 김진수;최은영;박현애;이우백
    • Health Policy and Management
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    • v.9 no.3
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    • pp.33-52
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    • 1999
  • The purpose of this study is to project the supply and demand for nurses till the year 2012 and to make recommendations for establishment of proper policies regarding them. To predict the supply of nurses. a baseline projection and demographic methods were employed. The derivative demand was used to forecast the demand of nurses. The results of this study provide us with valuable information on nursing manpower planning for the 21th century. Specifically. results indicate that there will be an oversupply of nurses in the near future based on the current productivity. Based on the medical law. there will be an undersupply of nurses till 2002 but an oversupply after that. Thus. the active supply of nurses must be decreased. One way to achieve this would be decreasing the size of training and education. Thus. we recommend that the number of entrances to 4 year programs will be reduced 20% in 2004. and a reduction of 20% by 2005 in 3 year programs. The results of this study suggest the following: First. a manpower bank for nurses who are trying to reenter the market must be established. Second, improvement of education and retraining is needed for the quality control of nurses. Further studies should take into consideration the above factors.

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Robust Fuzzy Logic Current and Speed Controllers for Field-Oriented Induction Motor Drive

  • El-Sousy, Fayez F.M.;Nashed, Maged N.F.
    • Journal of Power Electronics
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    • v.3 no.2
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    • pp.115-123
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    • 2003
  • This paper presents analysis, design and simulation for the indirect field orientation control (IFOC) of induction machine drive system. The dynamic performance of the IFOC under nominal and detuned parameters of the induction machine is established. A conventional proportional plus integral-derivative (PI-D) two-degree-of-freedom controller (2DOFC) is designed and analysed for an ideal IFOC induction machine drive at nominal parameters with the desired dynamic response. Varying the induction machine parameters causes a degredation in the dynamic response for disturbance rejection and tracking performance with PI-D 2DOF speed controller. Therefore, conventional controllers can nut meet a wide range of speed tracking performance under parameter variations. To achieve high- dynamic performance, a proposed robust fuzzy logic controllers (RFLC) for d-axis rotor flux, d-q axis stator currents and rotor speed have been designed and analysed. These controllers provide robust tracking and disturbance rejection performance when detuning occurres and improve the dynamic behavior. The proposed REL controllers provide a fast and accurate dynamic response in tracking and disturbance rejection characteristics under parameter variations. Computer simulation results demonstrate the effectiveness of the proposed REL controllers and a robust performance is obtained fur IFOC induction machine drive system.

Analysis of Radiation Characteristics of the Shaped Cassegrainian Antenna (수정곡면 카세그레인 안테나의 복사특성 해석)

  • Ryu, Hwang;Joo, Gi-Ho
    • The Journal of Engineering Research
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    • v.3 no.1
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    • pp.159-169
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    • 1998
  • The purpose of this study is to analyze the radiation characteristics of the shaped Cassegrainian antenna. Radiation pattern of the sub-reflector is calculated by GTD (Geometrical Theory of Diffraction) The complete radiation patterns are obtained by summing the reflect field from the surface and the diffracted fields from the edge. The first and the second derivative on the sub-reflector are calculated by the local interpolation technique. The Radiation characteristics of the main-reflector are obtained by integrating the surface current density, which is derived from PO approximation. The radiation integral is expanded by the Jacobi-Bessel series for the purpose of reducing the computation time.

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Ferutinin, an Apoptosis Inducing Terpenoid from Ferula ovina

  • Matin, Maryam Moghaddam;Nakhaeizadeh, Hossein;Bahrami, Ahamd Reza;Iranshahi, Mehrdad;Arghiani, Nahid;Rassouli, Fatemeh Behnam
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.5
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    • pp.2123-2128
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    • 2014
  • A current hurdle in cancer management is the intrinsic or acquired resistance of cancer cells to chemical agents that restricts the efficacy of therapeutic strategies. Accordingly, there is an increasing desire to discover new natural compounds with selective toxicity to combat malignancies. In present study, the cytotoxic and apoptosis-inducing activities of ferutinin, a terpenoid derivative from Ferula ovina, were investigated on human breast (MCF7) and bladder (TCC) cancer cells as well as normal fibroblasts (HFF3).The toxicity and DNA damage inducing effects of ferutinin were studied by MTT and comet assays, DAPI and PI staining and DNA laddering. The $IC_{50}$ values of ferutinin were identified and compared with routine prescribed drugs, doxorubicin and vincristine, by MTT test. Alkaline comet assay and DAPI staining revealed DNA damage due to ferutinin, which was significantly (p<0.001) higher in MCF7 and TCC than HFF3 cells. Apoptosis induction was evidenced by PI staining and DNA laddering. Our results suggest that ferutinin could be considered as an effective anticancer agent for future in vivo and clinical experiments.

OPTIMAL SHAPE DESIGN OF A S-SHAPED SUBSONIC INTAKE USING NURBS (NURBS를 이용한 S형 천음속 흡입관 최적 설계)

  • Lee B.J.;Kim C.
    • Journal of computational fluids engineering
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    • v.11 no.1 s.32
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    • pp.57-66
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    • 2006
  • An optimal shape design approach is presented for a subsonic S-shaped intake using aerodynamic sensitivity analysis. Two-equation turbulence model is employed to capture strong counter vortices in the S-shaped duct more precisely. Sensitivity analysis is performed for the three-dimensional Navier-Stokes equations coupled with two-equation turbulence models using a discrete adjoint method For code validation, the result of the flow solver is compared with experiment data and other computational results of bench marking test. To study the influence oj turbulence models and grid refinement on the duct flow analysis, the results from several turbulence models are compared with one another and the minimum number of grid points, which can yield an accurate solution is investigated The adjoint variable code is validated by comparing the complex step derivative results. To realize a sufficient and flexible design space, NURBS equations are introduced as a geometric representation and a new grid modification technique, Least Square NURBS Grid Approximation is applied With the verified flow solver, the sensitivity analysis code and the geometric modification technique, the optimization of S-shaped intake is carried out and the enhancement of overall intake performance is achieved The designed S-shaped duct is tested in several off-design conditions to confirm the robustness of the current design approach. As a result, the capability and the efficiency of the present design tools are successfully demonstrated in three-dimensional highly turbulent internal flow design and off-design conditions.

Characterization of Quorum-Sensing Signaling Molecules Produced by Burkholderia cepacia G4

  • Park, Jun-Ho;Hwang, In-Gyu;Kim, Jin-Wan;Lee, Soo-O;Conway, B.;Peter Greenberg, E.;Lee, Kyoung
    • Journal of Microbiology and Biotechnology
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    • v.11 no.5
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    • pp.804-811
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    • 2001
  • In many Gram-negative bacteria, autoinducers, such as N-acyl-L-homoserine lactone(acyl-HSL) and its derivative molecules, mediate the cell-density-dependnet expression of certain operons. The current study identified the autoinducers produced by Burkholderia cepacia G4, a trichloroethylene-degrading lagoon isolate, using TLC bioassays with Agrobacterium tumefaciens NT1(pDCI141E33) and Chromobacterium violaceum CVO26, and a GC-MS analysis. The ${R_f}\;and\;{R_t}$ values and mass spectra were compared with those of synthetic compounds. Based on the analyses, it was confirmed that G4 produces N-hexanoyl (C6)-, N-octanoyl (C8)-, N-decanoyl (C10)-, N-dodecanoyl (C12)-HSL, and an unknown active species. The integration of the GC peak areas exhibited a ratio of C8-HSL:C10-HSL:C12-HSL at 3:17:1 with C6-HSL and C10-HSL production at trace and micromolar levels, respectively, in the culture supernatants. Nutants partially defective in producing acyl-HSLs were also partially defective in the biosynthesis of an antibiotic substance. These results indicate that the autoinducer-dependent gene regulation in G4 is dissimilar to the clinical B. cepacia strains isolated from patients with cystic fibrosis.

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A Study on the Combustion Characteristics of Food Waste Using the Experimental Apparatus for Combustibility (소형 연소장치를 이용한 음식폐기물 연소 특성 연구)

  • Chae, JongSeong;Yang, SeungJae;Kim, SeokWan;Lee, JaeHee;Ohm, TaeIn
    • New & Renewable Energy
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    • v.16 no.2
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    • pp.47-53
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    • 2020
  • The amount of food waste and its water content depends on both the season and region. In particular, the water content typically varies between 73.8 wt.% and 83.3 wt.%, depending on the proportion of vegetables. Current food waste drying technologies are capable of reducing the water content to less than 10 wt.%, while increasing the heating value. Ongoing studies aim to utilize dried food waste as fuel. Food waste can be used to produce solid refuse fuel (SRF) by mixing it with various solid fuels or other types of waste. The analysis of specimens is very important when considering the direct combustion of food waste or its co-firing with solid fuels. In this study, the weight reduction of specimens after burning them in a small combustor, and compared with the results of thermogravimetric analysis (TGA). The concentration of various chemicals was also measured to define the characteristics of waste generation. Performed proximate analysis, elemental analysis, TGA, combustion experiment, the heating value, and derivative thermogravimetry (DTG).

Current Status and Prospects of Quality Evaluation in Sesame (참깨의 품질평가 현황과 전망)

  • 류수노;김관수;이은정
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.47
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    • pp.140-149
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    • 2002
  • Sesame (Sesamum indicum L.) is probably the most ancient oilseed crop known in the world. Sesame seed is known for its high nutritional value and for having oil (51%) and protein (20%) content. The fatty acid composition of sesame oil is palmitic acid (7.8%), stearic acid (3.6%), oleic acid (45.3%), and linoleic acid (37.7%). Sesame oil is characterized by a very high oxidative stability compared with other vegetable oils. Two lignan-type compounds, sesamin and sesamolin, are the major constituents of sesame oil unsaponifiables. Sesamol (a sesamolin derivative) can be present in sesame seeds and oils in very small amount. Other lignans and sesamol are also present in sesame seeds and oils in very small amount as aglycones. Lipid oxidation activity was significantly lower in the sesamolin-fed rats, which suggests that sesamolin and its metabolites contribute to the antioxidative properties of sesame seeds and oil and support that sesame lignans reduce susceptibility to oxidative stress. Sesaminols strongly inhibit lipid peroxidation related to their ability to scavenge free radical. The sesame seed lignan act synergistically with vitamin I in rats fed a low $\alpha$-tocopherol diet and cause a marked increase in a u-tocopherol concentration in the blood and tissue of rats fed an $\alpha$-tocopherol containing diet with sesame seed or its lignan. The authors are reviewed and discussed for present status and prospects of quality evaluation and researched in sesame seeds to provide and refers the condensed informations on their quality.

Molecular Dynamics Free Energy Simulation Study to Rationalize the Relative Activities of PPAR δ Agonists

  • Lee, Woo-Jin;Park, Hwang-Seo;Lee, Sangyoub
    • Bulletin of the Korean Chemical Society
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    • v.29 no.2
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    • pp.363-371
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    • 2008
  • As a computational method for the discovery of the effective agonists for PPARd, we address the usefulness of molecular dynamics free energy (MDFE) simulation with explicit solvent in terms of the accuracy and the computing cost. For this purpose, we establish an efficient computational protocol of thermodynamic integration (TI) that is superior to free energy perturbation (FEP) method in parallel computing environment. Using this protocol, the relative binding affinities of GW501516 and its derivatives for PPARd are calculated. The accuracy of our protocol was evaluated in two steps. First, we devise a thermodynamic cycle to calculate the absolute and relative hydration free energies of test molecules. This allows a self-consistent check for the accuracy of the calculation protocol. Second, the calculated relative binding affinities of the selected ligands are compared with experimental IC50 values. The average deviation of the calculated binding free energies from the experimental results amounts at the most to 1 kcal/mol. The computational efficiency of current protocol is also assessed by comparing its execution times with those of the sequential version of the TI protocol. The results show that the calculation can be accelerated by 4 times when compared to the sequential run. Based on the calculations with the parallel computational protocol, a new potential agonist of GW501516 derivative is proposed.

TD-CFIE Formulation for Transient Electromagnetic Scattering from 3-D Dielectric Objects

  • Lee, Young-Hwan;Jung, Baek-Ho;Sarkar, Tapan K.;Yuan, Mengtao;Ji, Zhong;Park, Seong-Ook
    • ETRI Journal
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    • v.29 no.1
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    • pp.8-17
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    • 2007
  • In this paper, we present a time domain combined field integral equation formulation (TD-CFIE) to analyze the transient electromagnetic response from dielectric objects. The solution method is based on the method of moments which involves separate spatial and temporal testing procedures. A set of the RWG functions is used for spatial expansion of the equivalent electric and magnetic current densities, and a combination of RWG and its orthogonal component is used for spatial testing. The time domain unknowns are approximated by a set of orthonormal basis functions derived from the Laguerre polynomials. These basis functions are also used for temporal testing. Use of this temporal expansion function characterizing the time variable makes it possible to handle the time derivative terms in the integral equation and decouples the space-time continuum in an analytic fashion. Numerical results computed by the proposed formulation are compared with the solutions of the frequency domain combined field integral equation.

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