• Title, Summary, Keyword: formulation

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Study of the semi-segregation algorithms of the incompressible Navier-Stokes equations using P2P1 finite element formulation (P2P1 유한요소 공식을 이용한 비압축성 Navier-Stokes 방정식의 반-분리 해법에 관한 연구)

  • Cho, Myung-H.;Choi, Hyoung-G.;Yoo, Jung-Y.;Park, Jae-I.
    • 유체기계공업학회:학술대회논문집
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    • pp.349-352
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    • 2006
  • The conventional segregated finite element formulation produces a small and simple matrix at each step than in an integrated formulation. And the memory and cost requirements of computations are significantly reduced because the pressure equation for the mass conservation of the Navier-Stokes equations is constructed only once if the mesh is fixed. However, segregated finite element formulation solves Poisson equation of elliptic type so that it always needs a pressure boundary condition along a boundary even when physical information on pressure is not provided. On the other hand, the conventional integrated finite element formulation in which the governing equations are simultaneously treated has an advantage over a segregated formulation in the sense that it can give a more robust convergence behavior because all variables are implicitly combined. Further it needs a very small number of iterations to achieve convergence. However, the saddle-paint-type matrix (SPTM) in the integrated formulation is assembled and preconditioned every time step, so that it needs a large memory and computing time. Therefore, we newly proposed the P2PI semi-segregation formulation. In order to utilize the fact that the pressure equation is assembled and preconditioned only once in the segregated finite element formulation, a fixed symmetric SPTM has been obtained for the continuity constraint of the present semi-segregation finite element formulation. The momentum equation in the semi-segregation finite element formulation will be separated from the continuity equation so that the saddle-point-type matrix is assembled and preconditioned only once during the whole computation as long as the mesh does not change. For a comparison of the CPU time, accuracy and condition number between the two methods, they have been applied to the well-known benchmark problem. It is shown that the newly proposed semi-segregation finite element formulation performs better than the conventional integrated finite element formulation in terms of the computation time.

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Development of the stable liquid formulation of Burkholderia cepacia YC5025, a biocontrol agent for cucumber anthracnose

  • Chung, Eu-Jeen;Chung, Young-Ryun
    • Proceedings of the Korean Society of Plant Pathology Conference
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    • pp.97.2-98
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    • 2003
  • A new and effective formulation using antagonistic bacteria, Burkholderia cepacia YC5025 in vegetable oil was developed for the biocontrol of anthracnose. The bacterial population in the formulation was maintained to 5x10/sup7/ cfu/ml upto 60 days at room temperature. Control efficacy of the formulation for anthracnose was over 80% by spraying of diluted suspension(x1,000) in growth chamber tests. On the contrary, the bacterial suspension in distilled water or bacterial culture broth containing same number of spores as the formulation had low control efficacy around 40% even 2-weeks storage after preparation. The shelf-life of the formulation was longer than that of bacterial preparation using clay minerals such as talc or bentonite. The mechanisms of newly developed bacterial formulation are possibly the formation of water film on the surface of cucumber leaves and inactivation of the bacteria in the vegetable oils during storage. Further field tests and improvements with new liquid bacteiral formulation need to be done for practical application.

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Query Formulation for Heuristic Retrieval in Obfuscated and Translated Partially Derived Text

  • Kumar, Aarti;Das, Sujoy
    • Journal of Information Science Theory and Practice
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    • v.3 no.1
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    • pp.24-39
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    • 2015
  • Pre-retrieval query formulation is an important step for identifying local text reuse. Local reuse with high obfuscation, paraphrasing, and translation poses a challenge of finding the reused text in a document. In this paper, three pre-retrieval query formulation strategies for heuristic retrieval in case of low obfuscated, high obfuscated, and translated text are studied. The strategies used are (a) Query formulation using proper nouns; (b) Query formulation using unique words (Hapax); and (c) Query formulation using most frequent words. Whereas in case of low and high obfuscation and simulated paraphrasing, keywords with Hapax proved to be slightly more efficient, initial results indicate that the simple strategy of query formulation using proper nouns gives promising results and may prove better in reducing the size of the corpus for post processing, for identifying local text reuse in case of obfuscated and translated text reuse.

Development of Sustainable Releasing Micro Formulation System using γ-Irradiation Technique to Control Phytophthora Blight Disease

  • Park, Hae-Jun;Kim, Hwa-Jung;Kim, Dong Ho
    • Journal of Radiation Industry
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    • v.5 no.4
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    • pp.305-311
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    • 2011
  • We introduced a novel sustainable slow-releasing agrochemical formulation, a biopolymer bound to silica, for controlling plant diseases. The formulation was obtained through the following process. Curdlan, sodium silicate ($Na_2SiO_3$) and isopropyl alcohol were dissolved in DDW (Deionized-distilled water). The resultant solution was then irradiated using a $^{60}Co$ ${\gamma}$-irradiator (150 TBq of capacity; ACEL, Canada) at KAERI. The resultant solution was treated with phosphorous acid ($H_3PO_3$). Finally, we obtained a novel biopolymer-silica microsized formulation containing phosphorous acid ($H_3PO_3$) from the solution. The morphology of the complex was characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM and TEM images revealed that the curdlan-silica formulation has a particle size ranging from 1 to $3{\mu}m$ with high stability. We also detected that $H_3PO_3$ was distributed within the formulation through energy dispersive X-ray spectroscopy (EDX) analysis. $H_3PO_3$ was sustain-released from the formulation in water. Based on our results, it seems effectively that one or two applications of the formulation during a cropping season will assist in controlling various plant diseases.

Mathematical Programming Approaches to GT Cell Formation: A Comparative Study

  • 원유경
    • Korean Management Science Review
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    • v.16 no.2
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    • pp.137-147
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    • 1999
  • This paper compares and evaluates the performances of the two types of mathematical programming models for solving the machine-part cell formation problem in group technology manufacturing : indirect formulation relying on surrogate measure such as similarity coefficient and direct formulation seeking to minimize the number of exceptional elements. New indirect formulation, called the generalized {{{{ { p}_{ } }}-median model. is proposed. Unlike existing {{{{ { p}_{ } }}-median formulations, proposed formulation includes the classical cell formation problem in which only one process plan exsits for each part as a special case. The proposed new formulation can also deal with the cell formation problem in which alternative process plans exist for a part. The indirect formulation is compared with a new direct formulation which needs much fewer extra variables and constraints than existing direct formulations. Some significant findings from comparative experiment are discussed.

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Preconditioning Method of a Finite Element Combined Formulation for Fluid-Structure Interaction (유체-구조물 상호작용을 위한 유한요소 결합공식화의 예조건화에 대한 연구)

  • Choi, Hyoung-Gwon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.4
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    • pp.242-247
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    • 2009
  • AILU type preconditioners for a two-dimensional combined P2P1 finite element formulation of the interaction of rigid cylinder with incompressible fluid flow have been devised and tested by solving fluid-structure interaction (FSI) problems. The FSI code simulating the interaction of a rigid cylinder with an unsteady flow is based on P2P1 mixed finite element formulation coupled with combined formulation. Four different preconditioners were devised for the two-dimensional combined P2P1 finite element formulation extending the idea of Nam et al., which was proposed for the preconditioning of a P2P1 mixed finite element formulation of the incompressible Navier-Stokes equations. It was found that PC-III or PC-IV among them perform well with respect to computational memory and convergence rate for some bench-mark problems.

General Asymptotic Formulation for the Bifurcation Problem of Thin Walled Structures in Contact with Rigid Surfaces

  • Kwon, Young-Joo;Triantafyllidis, N.
    • Journal of Mechanical Science and Technology
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    • v.14 no.1
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    • pp.48-56
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    • 2000
  • The bifurcation problem of thin walled structures in contact with rigid surfaces is formulated by adopting the multiple scales asymptotic technique. The general theory developed in this paper is very useful for the bifurcation analysis of waviness instabilities in the sheet metal forming. The formulation is presented in a full Lagrangian formulation. Through this general formulation, the bifurcation functional is derived within an error of O($(E^4)$) (E: shell's thickness parameter). This functional can be used in numerical solutions to sheet metal forming instability problem.

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A Mixed Formulation of Lactic Acid Bacteria Inhibits Trinitrobenzene-Sulfonic-Acid-Induced Inflammatory Changes of the Colon Tissue in Mice

  • Cha, Yeon Suk;Seo, Jae-Gu;Chung, Myung-Jun;Cho, Chung Won;Youn, Hyun Joo
    • Journal of Microbiology and Biotechnology
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    • v.24 no.10
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    • pp.1438-1444
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    • 2014
  • Lactic acid bacteria (LAB) are probiotics that provide numerous beneficial effects on the host body, especially on the intestine. Combining several strains of LAB, we prepared a formulation containing four different LAB and studied its anti-inflammatory activity both in vitro and in vivo. The formulation significantly reduced NO production from RAW 264.7 cells treated with bacterial lipopolysaccharide, indicating that the formulation might include anti-inflammatory activity. The formulation also suppressed inflammatory change induced by trinitrobenzene sulfonic acid (TNBS) in mice, where oral or rectal administration of the formulation protected the colon tissue from the damage by TNBS. Expressions of the IL-6 and FasL genes appeared to be down-regulated by the formulation in TNBS-treated colon tissues, suggesting that the suppression of those genes may be involved in the anti-inflammatory activity of the formulation.

Partitioning method using kinematic uncoupling in train dynamics (열차 동역학에서 기구학적 비연성을 이용한 분할 해석 방법)

  • 박정훈;유흥희;황요하;김창호
    • Proceedings of the KSR Conference
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    • pp.437-444
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    • 1998
  • In this paper, an efficient and accurate formulation for the transient analysis of constrained multibody systems is presented. The formulation employs Kane's method along with the null space method. Kane's method reduces the dimension of equations of motion by using partial velocity matrix: it can improve the efficiency of the formulation. Furthermore, the formulation partitions the coefficient matrix of linear and nonlinear equations into several sub-matrices using kinematic uncoupling. This can solve the equations more efficiently. The proposed formulation can be used to perform dynamic analysis of systems which can he partitioned into several sub-systems such as train systems. One numerical example is given to demonstrate the efficiency and accuracy of the formulation, and another numerical example is given to show its application to the train systems.

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